System and method for air embossing fabrics utilizing improved air lances

Information

  • Patent Grant
  • 6770240
  • Patent Number
    6,770,240
  • Date Filed
    Friday, March 8, 2002
    22 years ago
  • Date Issued
    Tuesday, August 3, 2004
    19 years ago
Abstract
Air embossing systems, air lances and methods of air embossing fabrics produce fine detail, crisp transition between unembossed and embossed regions, and a high degree of uniformity across the width of an embossed fabric. The air embossing systems utilize air lances (210) for directing a stream of air onto the embossable surface (113) of a fabric (111) that have at least one nozzle (216) having an orifice dimension substantially less than that of conventional nozzles. The air embossing systems can also include air lance nozzles positioned in proximity to the embossable surface, nozzles with an orifice dimension that is substantially less than the nozzle length, nozzles in the shape of an elongated slit oriental across essentially the entire width of the fabric, air lances including a nozzle-forming component (214) separable from the main body (212) of the air lance to enable the nozzle to be positioned within close proximity to the fabric and to redirect air to be emitted such that a substantial fracti n of the air stream is directed perpendicular to the fabric surface, and air lances including baffles r air redirecting elements (340) which deflect air to pass through the nozzle and nt the fabric surface at an increased angle, relative to the air lance longitudinal axis.
Description




FIELD OF THE INVENTION




The present invention relates to systems and methods for embossing a surface of an embossable fabric with a stream of air, and embossed flocked fabrics made thereby.




BACKGROUND OF THE INVENTION




In manufacturing flocked fabric it is conventional to deposit a layer of flock on an adhesive coated substrate and to emboss the surface of the flocked fabric during this process with selected designs. Conventionally, the embossing process may be achieved by one of several processes using specialized equipment for such purposes. Among these embossing processes is air embossing. In the air embossing process a substrate is coated with an adhesive. While the adhesive is still wet it is covered with a layer of flock fibers forming the flocked layer. The adhesive coated substrate with the flocked fibers is then carried beneath a stencil while the adhesive is not yet set. The stencil under which the assembly moves typically comprises an elongated cylinder having perforations arranged in a desired pattern to be formed in the flocked surface. This embossing stencil typically is rotated at the same speed as the flocked layer moves beneath it. Air introduced within this cylindrical stencil is directed downwardly through the perforations forming the pattern onto the upper surface of the flocked layer. By choosing a particular arrangement of perforations in the screen, and by the selective application of air flow through the perforations, air jets are projected downwardly from the stencil onto the surface of the flocked fabric. Since the flocked fabric has not yet set in the adhesive, the stream of air changes the angle of or substantially flattens the flock fibers forming the flock in selected areas, thus forming a pattern as the stencil rotates and the flocked fabric moves.




A variety of prior art systems are available for performing air embossing of flocked fabrics. Many such systems are generally satisfactory for embossing designs onto an embossable surface of the fabric that do not require a significant level of fine detail. However, typical prior art systems suffer from a variety of shortcoming which limit their utility for producing finely detailed patterns, and which result in embossed pile fabrics that include embossed regions having undesirable artifacts and visually unappealing surface features. For example, air embossed pile fabrics produced with conventional air embossing equipment are typically not able to produce embossed features having a characteristic size that is very small, thus such equipment is not able to give the embossed fabric an appearance with a fine, detailed surface structure. In addition, typical prior art air embossing systems are not able to direct air towards the embossable surface of the fabric at a controlled, desirable angle (e.g. essentially perpendicular to the fabric surface), and, thus, they tend to produce embossed features having a blurred or imprecise transition region between the embossed features and the unembossed regions of the surface, which results in an associated lack of crispness and definition to the overall appearance of the embossed fabric.




In addition, typical prior art air embossing systems also tend to produce embossed fabrics having embossed features distributed across the width of the fabric that are not uniform in appearance across the width of the fabric. Also, typical prior art air embossing systems have a tendency to direct air towards the surface of the fabric in a direction diagonal to the fabric surface resulting in an embossed surface wherein the pile fibers have an overall directional lay with respect to the substrate, thus creating a distorted, unattractive appearance in the embossed surface, which appearance does not accurately reflect the pattern provided in the stencil used for embossing.




The present invention is directed to improved air embossing systems and methods and improved embossed fabrics produced using the systems and methods. The invention provides a variety of air embossing systems utilizing improved air lances for directing air onto and through a patterned stencil of the system. The improved air lances and embossing systems provided by the invention are able, in many embodiments, to solve many of the above-mentioned short comings of prior art air embossing systems and to produce embossed fabrics having an unprecedented level of fine detail, crisp transition between unembossed and embossed regions, and uniformity across the width of the embossed fabric.




SUMMARY OF THE INVENTION




The present invention provides, in some embodiments, improved air embossing systems, improved air lances, and improved methods of air embossing fabrics, which are able to produce an unprecedented level of fine detail, crisp transition between unembossed and embossed regions, and a high degree of uniformity across the width of an embossed fabric, when compared to the performance of typical, conventional air embossing systems, air lances, and embossing methods. The air embossing systems provided by the invention, in some embodiments, utilize air lances for directing a stream of air onto the embossable surface of a fabric that have at least one nozzle having a characteristic orifice dimension substantially less than that of conventional air lance nozzles. The disclosed air embossing systems can also include air lances having nozzles positioned in close proximity to the embossable surface of a fabric being embossed, substantially closer than is typical for air lances employed in conventional air embossing systems. Air lances provided according to the invention can also include one or more nozzles having a characteristic orifice dimension that is substantially less than a characteristic length of the nozzles. Certain air lances provided according to the invention can also include one or more nozzles in the shape of an elongated slit oriented, with respect to the air lance, so as to be positioned across essentially the entire width of a fabric being embossed with the air lance. The invention also provides air lances for use in embossing fabrics that can include a nozzle-forming component that is separable from the main body of the air lance and that enables the nozzle(s) of the air lance to be positioned within close proximity to the fabric, when the air lance is in operation, and that also can act to redirect air flowing within the air lance such that it is emitted from the nozzle(s) so that a substantial fraction of the air stream is directed essentially perpendicular to the surface of the fabric being embossed. Yet other air lances disclosed include therein one or more baffles or air redirecting elements, which serve to deflect air flowing within the air lance so that it passes through the nozzle(s) and is directed onto the embossable surface of the fabric at an angle that is substantially greater, with respect to the longitudinal axis of the air lance, than the angle of an air stream emitted from a nozzle of an essentially equivalent air lance, except excluding the air redirecting element or baffle. Some of the air lances described according to the invention can include a combination of several or all of the above described features.




In one embodiment, a system for air embossing a surface of an embossable fabric is disclosed. The system comprises a stencil having a first surface and a second, fabric-facing surface that is positionable adjacent and in spaced proximity to the embossable surface of the fabric during air embossing. The system further comprises an air lance comprising a main body portion and including at least one nozzle. The nozzle is constructed and positioned to direct a stream of air through at least one opening in the stencil and onto the embossable surface. The air lance is secured within the system to maintain the nozzle in a fixed, predetermined position relative to the first surface of the stencil during operation. The air lance is positioned such that the nozzle is positioned so that at least a portion thereof, which is closest to the stencil, is separated from the first surface of the stencil by a first distance, when the system is in operation. The air lance is also positioned such that the smallest distance separating the main body portion of the air lance from the first surface of the stencil exceeds the first distance.




In another embodiment, a system for air embossing a surface of an embossable fabric is disclosed. The system comprises a stencil and an air lance including at least one nozzle thereon. The nozzle is constructed and positioned to direct a flow of air through the stencil and onto the embossable surface of the fabric, when the system is in operation. The system further comprises a substantially smooth support surface comprising a cylindrical roller constructed and arranged to support the underside of the fabric during air embossing of the embossable surface of the fabric with the system. The cylindrical roller is positioned directly beneath and spaced apart from the nozzle such that a stream of air exiting the nozzle is directed to impinge upon the fabric at a location where the fabric is adjacent to and in contact with the cylindrical roller, when the system is in operation.




In another aspect, an air lance for directing air through a stencil and onto a surface of an embossable fabric for air embossing the fabric is disclosed. The air lance comprises a conduit having at least one opening therein and at least one orifice forming at least one nozzle. The nozzle is constructed and positioned to direct a stream of air through the stencil and onto the embossable surface of the fabric when the air lance is in operation. The nozzle has a characteristic orifice dimension not exceeding about 0.05 inch.




In another embodiment, an air lance for directing air through a stencil and onto a surface of an embossable fabric for air embossing the fabric is disclosed. The air lance comprises a conduit having at least one inlet opening therein and at least one orifice forming at least one nozzle. The nozzle is constructed and positioned to direct a stream of air through the stencil and onto the embossable surface of the fabric when the air lance is in operation. The nozzle has a characteristic orifice dimension not exceeding a maximum characteristic length of the nozzle.




In yet another embodiment, an air lance for directing air through a stencil and onto a surface of an embossable fabric for air embossing the fabric is disclosed. The air lance comprises a conduit having an elongated main body portion with at least one inlet opening and at least one outlet opening therein. The air lance further includes a nozzle-forming component connected to the main body portion and extending along a substantial fraction of the length of the main body portion. The nozzle-forming component includes at least one orifice therein forming a nozzle. The nozzle is in fluid communication with the outlet opening of the main body portion and is constructed and positioned to direct a stream of air through at least one opening in the stencil and onto the embossable surface of the fabric when the air lance is in operation. The nozzle-forming component is shaped and positioned so that the nozzle in the nozzle-forming component is separated from a first surface of the stencil onto which air is impinged by a distance that is substantially less than a distance separating the first surface of the stencil and the outlet opening in the main body portion of the conduit.




In yet another embodiment, an air lance for directing air through a stencil and onto a surface of an embossable fabric for air embossing the fabric is disclosed. The air lance comprises an elongated tubular conduit having at least one inlet opening therein and at least one internal support strut attached therein. The support strut is constructed and positioned within the conduit to resist expansion of the conduit when the air lance is in operation. The air lance includes at least one orifice in the shape of an elongated slit forming at least one nozzle. The nozzle is constructed and positioned to direct a stream of air through at least one opening in the stencil and onto the embossable surface of the fabric, when the air lance is in operation.




In another embodiment, an air lance for directing air through a stencil onto a surface of an embossable fabric for air embossing the fabric is disclosed. The air lance comprises a conduit having at least one opening therein and at least one orifice forming at least one nozzle. The nozzle is constructed and positioned to direct a stream of air through at least one opening in the stencil and onto the embossable surface of the fabric when the air lance is in operation. The air lance further comprises at least one air redirecting element constructed and positioned with respect to the nozzle so that the fractional amount of the stream of air directed through the opening in the stencil essentially perpendicular to the embossable surface of the fabric is increased with respect to a fractional amount of a stream of air directed through the opening in the stencil essentially perpendicular to the embossable surface of the fabric by an essentially equivalent air lance, except not including the air redirecting element.




In another aspect, a method for air embossing a surface of an embossable fabric is disclosed. The method comprises supplying a flow of air to an air lance and flowing a stream of air through at least one nozzle of the air lance so that essentially the entire stream of air is directed towards a surface of a stencil facing and adjacent the nozzle at an angle of at least about 45 degrees with respect to a longitudinal axis of the air lance. The method further comprises passing the stream of air through at least one opening in the stencil and impinging the stream of air onto the embossable surface of the fabric, thereby embossing the embossable surface of the fabric.




In another embodiment, a method for air embossing a surface of an embossable fabric is disclosed. The method comprises supplying a flow of air to an elongated air lance including one or more nozzles positioned along a substantial fraction of the length of the air lance. The method further comprises flowing a stream of air through the one or more nozzles such that the air velocity through the one or more nozzles is essentially constant along the substantial fraction of the length of the air lance. The method further includes passing the stream of air through at least one opening in the stencil and impinging the stream of air onto the embossable surface of the fabric, thereby embossing the embossable surface of the fabric.




In yet another embodiment, a method for embossing a surface of an embossable fabric is disclosed. The method comprises supplying a flow of air to an air lance, flowing a stream of air through at least one nozzle of the air lance so that the velocity of the air exiting the nozzle is at least about 12,000 ft/min, passing the stream of air through at least one opening in the stencil, impinging the stream of air onto the embossable surface of the fabric, and embossing the embossable surface of the fabric with a predetermined pattern of embossed features.




In another embodiment, a method for air embossing a surface of an embossable fabric is disclosed. The method comprises supplying a flow of air to an air lance, flowing a stream of air through at least one nozzle of the air lance, rotating a cylindrical stencil disposed around at least a portion of the air lance at a first speed, passing the stream of air through at least one opening in the rotating stencil, moving the fabric adjacent to an outer surface of the stencil at a second speed that is different from the first speed of the rotating stencil, impinging the stream of air onto the embossable surface of the fabric, and embossing the embossable surface of the fabric with a predetermined pattern of embossed features.




In another embodiment, a method for air embossing a surface of an embossable fabric is disclosed. The method comprises positioning at least a portion of at least one nozzle of an air lance within a first separation distance from a first surface of a stencil, positioning a main body portion of the air lance so that the smallest distance separating the main body portion from the first surface of the stencil exceeds any distance separating the nozzle from the first surface of the stencil, forming a stream of air with the air lance by passing air through the nozzle of the air lance, and directing the stream of air through at least one opening in the stencil and onto the embossable surface of the fabric to form a predetermined pattern of embossed features.




In yet another embodiment, a method for air embossing a surface of an embossable fabric is disclosed. The method comprises positioning a substantially smooth support surface comprising a cylindrical roller directly beneath and spaced apart from the nozzle of the air lance. The method further comprises supporting the underside of the embossable fabric with the cylindrical roller and directing a stream of air with the nozzle through a stencil and onto the embossable surface of the fabric such that the stream of air impinges upon the fabric at a location where the fabric is adjacent to and in contact with the cylindrical roller.




In yet another embodiment, a method for air embossing a surface of an embossable fabric is disclosed. The method comprises directing a stream of air though a stencil and onto the embossable surface of the fabric with an air lance including a conduit, having at least one inlet opening therein, and at least one orifice forming at least one nozzle having a characteristic orifice dimension not exceeding about 0.05 inch.




In another embodiment, a method for air embossing a surface of an embossable fabric is disclosed. The method comprises directing a stream of air through a stencil and onto the embossable surface of the fabric with an air lance including a conduit, having at least one inlet opening therein, and at least one orifice forming at least one nozzle having a characteristic orifice dimension not exceeding a maximum characteristic length of the nozzle.




In yet another embodiment, a method for air embossing a surface of an embossable fabric is disclosed. The method comprises directing a stream of air through a stencil an onto the embossable surface of the fabric with an air lance including a conduit, and a nozzle forming component including at least one orifice therein forming a nozzle that is in fluid communication with the outlet opening in the main body portion. The nozzle forming component is shaped and positioned to extend along a substantial fraction of the length of the main body portion and so that the nozzle in the nozzle forming component is separated from a first surface of the stencil, onto which the stream of air is impinged, by a distance that is substantially less than a distance separating the first surface of the stencil and the outlet opening in the main body portion of the conduit.




In another aspect, in a system for air embossing an embossable fabric, means are disclosed for directing a stream of air onto the embossable surface of the fabric from a distance of no more than about 0.75 inch, with at least one cross-sectional dimension of the air stream being no more than about 0.2 inch at its source.




In yet another aspect, an air embossing system for embossing a surface of an embossable fabric is disclosed. The air embossing system comprises an elongated conduit extending across and substantially parallel to the embossable fabric and further includes means for redirecting air flowing along the length of the conduit so that essentially all of the air flow exits from at least one outlet opening in the conduit towards the fabric in a direction making an angle of at least about 45 degrees with respect to the longitudinal axis of the elongated conduit, with the means comprising a series of baffles shaped and positioned to intercept and deflect the air flow.




In another embodiment, a method for embossing a surface of an embossable fabric is disclosed. The method comprises directing a stream of air through a stencil and onto the embossable surface of the fabric with an air lance including an elongated tubular conduit. The conduit has at least one inlet opening therein, at least one internal support strut attached therein, which support strut is constructed and positioned within the conduit to resist expansion of the conduit when the air lance is in operation, and at least one orifice in the shape of an elongated slit forming at least one nozzle.




In yet another embodiment, a method for air embossing a surface of an embossable fabric is disclosed. The method comprises directing a stream of air through a stencil and onto the embossable surface of the fabric with an air lance including a conduit, the air lance having at least one inlet opening therein, at least one orifice forming at least one nozzle, and at least one air redirecting element constructed and positioned with respect to the nozzle so that the fractional amount of the stream of air directed through the stencil essentially perpendicular to the embossable surface of the fabric is increased with respect to a fractional amount of a stream of air directed through the stencil essentially perpendicular to the embossable surface of the fabric by an essentially equivalent air lance, except not including the air redirecting element.




Other advantages, novel features, and objects of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings, which are schematic and which are not intended to be drawn to scale. In figures, each identical, nearly identical, or closely similar component that is illustrated in various figures is represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the invention shown where illustration is not necessary to allow those of ordinary skill in the art to understand the invention.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1



a


is a schematic perspective view of an unembossed pile fabric;





FIG. 1



b


is a cross-sectional schematic illustration of the pile fabric shown in

FIG. 1



a;







FIG. 2



a


is a schematic perspective view of an embossed pile fabric produced in accordance with the present invention;





FIG. 2



b


is a cross-sectional schematic illustration of the embossed pile fabric of

FIG. 2



a;







FIG. 2



c


is a cross-sectional schematic illustration of an embossed pile fabric similar to that shown in

FIG. 2



b


, except produced using prior art air embossing technology;





FIG. 3

is a schematic diagram of a process for embossing a pile fabric according to one embodiment of the invention;





FIG. 4



a


is a schematic perspective view of an air embossing system for producing an embossed pattern on a pile fabric, as viewed from the right, according to one embodiment of the invention;





FIG. 4



b


is a schematic perspective view of an air embossing system for producing an embossed pattern on a pile fabric, as viewed from the left, according to one embodiment of the invention;





FIG. 4



c


is a schematic perspective view of an air embossing system for producing an embossed pattern on a pile fabric, as viewed from underneath the fabric, according to one embodiment of the invention;





FIG. 4



d


is a schematic illustration of an embossing cylinder for producing an embossed pattern on a pile fabric according to one embodiment of the invention;





FIG. 5

is a cross-sectional schematic illustration of certain components of the air embossing system of

FIGS. 4



a


-


4




c


, including an air lance mounted therein;





FIG. 6



a


is a schematic illustration of an air distribution lance for use in an air embossing process according to one embodiment of the invention, as viewed from the bottom;





FIG. 6



b


is a schematic illustration of the air distribution lance of

FIG. 6



a


, as viewed from the side;





FIG. 6



c


is a cross-sectional view of the air distribution lance of

FIG. 6



a;







FIG. 6



d


is a cross-sectional view of a first alternative embodiment of the air distribution lance of

FIG. 6



a;







FIG. 6



e


is a cross-sectional view of a first alternative embodiment of the air distribution lance of

FIG. 6



a;







FIG. 6



f


is a cross-sectional view of a second alternative embodiment of the air distribution lance of

FIG. 6



a;







FIG. 6



g


is a cross-sectional view of a second alternative embodiment of the air distribution lance of

FIG. 6



a;







FIG. 7



a


is a schematic illustration of an air distribution lance for use in an air embossing process according to another embodiment of the invention, as viewed from the bottom;





FIG. 7



b


is a schematic illustration of the air distribution lance of

FIG. 7



a


, as viewed from the side;





FIG. 7



c


is a cross-sectional view of the air distribution lance of

FIG. 7



a;







FIG. 7



d


is a cross-sectional view of the air distribution lance of

FIG. 7



a;







FIG. 8



a


is a schematic illustration of an air distribution lance for use in an air embossing process according to yet another embodiment of the invention, as viewed from the, bottom;





FIG. 8



b


is a schematic illustration of the air distribution lance of

FIG. 8



a


, as viewed from the side;





FIG. 8



c


is a cross-sectional view of the air distribution lance of

FIG. 8



a;







FIG. 8



d


is a cross-sectional view of the nozzle-forming component of the air distribution lance of

FIG. 8



a;







FIG. 8



e


is a cross-sectional view of an alternative embodiment of the air distribution lance of

FIG. 8



a;







FIG. 8



f


is a cross-sectional view of the nozzle-forming component of the air distribution lance of

FIG. 8



e;







FIG. 9



a


is a schematic illustration of the air redirecting element of the air lance of

FIG. 8



a; and







FIG. 9



b


is a cross-sectional view of the air redirecting element of

FIG. 9



a.













DETAILED DESCRIPTION




The present invention provides a variety of improved air embossing systems and methods of operation of air embossing systems that are able to improve the performance of such systems and result in the production of embossed fabrics which have an unprecedented level of fine detail and uniformity to the embossed pattern. As will become more apparent from the detailed description below, an important factor in the performance of air embossing systems is the design and positioning of the air lance, which distributes air through a patterned stencil and onto the surface of the fabric, within the system. The present invention provides, in some embodiments, a variety of improved air lance designs and improved systems for positioning the air lance with respect to the stencil and fabric.




The present invention is directed to methods and systems for air embossing an embossable fabric. It should be understood that while the invention is described in the embodiments below in the context of embossable fabrics comprising flocked, pile fabrics, that the invention is not so limited and that an embossable fabric as used herein encompasses any fabric having at least one embossable surface. An “embossable surface” refers to a surface that can be permanently or temporarily visibly altered by an air stream impinging thereon. In addition, while the present invention is described as utilizing air for embossing an embossable surface of a fabric, it should be understood that other gases may be substituted for air, as would be apparent to those of ordinary skill in the art.




While in some embodiments the air embossing systems of the present invention may include an air lance directing a stream of air directly onto the embossable surface of an embossable fabric to form a pattern thereon, in preferred embodiments, the air stream from the air lance is directed through a stencil before impinging upon the surface of the fabric. A “stencil” as used herein defines a gas impermeable surface having a plurality of apertures therein oriented in a pattern on the surface. The air directed from the air lance onto the surface of the stencil, in such systems, is interrupted by the solid gas-impermeable stencil but passes freely through the openings or apertures within the stencil, thus forming an embossed pattern on the surface of the fabric dictated by the pattern of apertures within the stencil. Stencils for use according to the invention can comprise flat or cylindrical surfaces, and the surfaces may be stationary or movable with respect to the embossable surface of the fabric during operation of the air embossing system.




An “air lance” as used herein refers broadly to a conduit, manifold, or other object able to direct a stream of air onto the surface of a stencil and/or embossable fabric. In preferred embodiments, described in detail below, the air lance comprises an elongated conduit, extending across essentially the entire width of the fabric that is embossed by the system, which includes at least one nozzle for directing the stream of air. A “nozzle,” as used herein, refers to the smallest orifice within the air lance through which an air stream passes. As shown in more detail below, some of the air lances provided according to the invention include a plurality of discrete nozzles therein, for example, a plurality of nozzles comprising individual holes within the air lance, each of which direct a stream of air toward the surface of an embossable fabric. In such embodiments, each of such holes comprises a “nozzle.” For embodiments where the nozzles are not all of the same size, or where the air lance includes a nozzle having a characteristic dimension that is non-uniform along the length of the air lance, the “smallest orifice in the air lance through which an air stream passes,” which defines a “nozzle”, refers to the smallest orifice in the lance through which any portion or component of the air stream passes. In other words, for embodiments including a nozzle or nozzles that are non-uniform in size, as described above, the smallest orifice through which any given molecule or atom of the air stream passes before exiting the air lance comprises a “nozzle”.




In preferred embodiments of the invention, the nozzle or nozzles within the air lance are constructed and positioned to direct a stream of air through at least one opening in a stencil and onto an embossable surface of the fabric. The term “constructed and positioned to direct a stream of air through at least one opening in a stencil and onto an embossable surface” of a fabric as used herein refers to the nozzle(s) being sized and positioned within the air embossing system such that at least a portion of an air stream emitted from the nozzle(s) is directed through an opening of the stencil and onto the embossable surface of the fabric.




Conventional prior art air lances utilized for air embossing fabrics typically comprise a long tubular conduit having a single row of holes extending lengthwise along the tube so that they traverse the width of the fabric when the air lance is positioned for use. The holes, comprising nozzles of the air lance, in prior art configurations, are typically relatively large in diameter (e.g., greater than about 0.25 inch in diameter). The open area in the air lance formed by the nozzles also, in conventional designs, is at least about 40% of the internal cross sectional area of the main body of the air lance. Also, in conventional air embossing systems, the nozzles are positioned spaced apart from the stencil through which the air is directed by a relatively large distance of at least about 1 inch.




The above-described conventional air lance designs are not well suited for producing finely detailed embossed patterns in fabrics, which patterns have a uniform visual appearance across the width of the embossed fabric. Such finely detailed embossed patterns in fabrics are highly desirable in the marketplace and are enabled and provided by the improved systems and methods according to the invention. The air lances and air embossing systems utilizing the air lances provided according to the invention include a variety of improvements over the above-described prior art system, which improvements, alone or in combination, can solve many of the above-mentioned problems inherent in the prior art systems.




For example, some embodiments of air embossing systems provided according to the invention include air lances that are designed so that the distance separating the nozzle(s) from the stencil is significantly less than for prior art systems. In combination with the above, or in other embodiments, the invention also provides air embossing systems with air lances having a nozzle(s) with a characteristic dimension smaller than typical prior art nozzle sizes. In combination with the above, or in other embodiments, air lances provided according to the invention can include a nozzle(s) having a total open area that is significantly smaller with respect to a cross-sectional area of a conduit comprising the main body of the air lance than for typical prior art air lances. In combination with the above, or in other embodiments, the invention also involves emitting an air stream from the nozzle(s) of the air lance at a velocity that is significantly higher than that created by conventional air embossing systems. In combination with the above, or in other embodiments, the air lances provided according to the invention also can include nozzle(s) formed in the shape of a continuous slit, as opposed to the discrete holes comprising nozzles typically included in conventional air lances. In combination with the above, or in other embodiments, the invention also provides air lances that can include air redirecting elements or baffles therein, and/or nozzles that are shaped to create more focused and collimated air flow therethrough when compared to conventional air lance nozzles.




Certain of the above-mentioned inventive features, when utilized alone or in combination with other of the above-mentioned features, or in combination with other inventive features of the air embossing systems described in more detail below, can solve many of the problems associated with typical prior art air embossing systems. For example, air embossing systems and air lances provided according to the invention can create, in some embodiments, a fabric embossing air steam having a high degree of collimation, a low degree of turbulence, and a high flow velocity, yielding better definition and more fine detail in fabric surfaces embossed with the inventive systems. The inventive systems, in some embodiments, also provide air lances which can emit an air stream having a more even and uniform air flow velocity distribution across the entire width of the air lance nozzle region than is achievable in typical prior art air lances. The inventive air embossing systems, in some embodiments, also can eliminate visible embossing artifacts present in an embossed fabric and created by the shape and configuration of typical air lance nozzle designs that are utilized in conventional air lances. In addition, some embodiments of air embossing systems according to the invention can eliminate or reduce visible embossing artifacts present in an embossed fabric surface and created by air impinging upon the surface of the fabric diagonally thereto, which creates an overall visual directionality of the surface and a resulting distortion of the embossed pattern, which is undesirable.




Those skilled in the art would readily appreciate that all parameters listed herein are meant to be exemplary and that the actual parameters for a given system or method will depend upon the specific application for which the methods and apparatuses of the present invention are used. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described.




A conventional flocked fabric


10


, which is unembossed, is shown in

FIG. 1



a


, and in cross-section in

FIG. 1



b


. The fabric is comprised of a substrate layer


12


which is coated by an adhesive layer


14


, which is, in turn, coated by a pile layer


16


that is comprised of a plurality of short lengths of pile fiber


18


that adhere to adhesive layer


14


. As shown in

FIG. 1



b


, for an unembossed pile fabric, the individual pile fibers


18


are typically oriented essentially parallel to each other and essentially perpendicular to the surface of the adhesive layer


14


in which they are embedded.




Substrate


12


, as shown, is comprised of a woven fabric formed by warp yarns


21


and fill yarns


23


. Substrate


12


can be formed from a variety of woven materials incorporating natural and/or synthetic fibers, or combinations thereof. In one particular embodiment, the substrate can comprise a poly-cotton blend of 65%/35% having a weight in the order of 3.0 to 3.5 oz/sq. yd. While in the illustrated embodiment, a woven fabric is shown as a substrate, it should be understood that in other embodiments, substrate


12


may be any type of material suitable for flocking with a pile layer, such as a variety of woven fabrics, nonwoven fabrics, knitted fabrics, porous or non-porous plastic and paper sheets, and the like, as apparent to those of ordinary skill in the art.




Adhesive layer


14


can be any conventional adhesive known in the art for use in fabricating flocked pile fabrics. Such adhesives include a wide variety of water based and/or solvent based adhesives. Also, as apparent to those of ordinary skill in the art, the adhesives may further include such components as viscosity modifiers, plasticizers, thermosetting resins, curing catalysts, stabilizers, and other additives well known in the art. The viscosity and composition of the adhesive chosen can be selected according to criteria readily apparent to those of ordinary skill in the art, including, but not limited to, the porosity and composition of substrate


12


, the desired cure time and technique employed, the particular method of depositing pile fibers


18


onto the adhesive, the final weight and hand of the pile fabric desired, etc. In one particular embodiment, adhesive layer


14


comprises an acrylic polymer adhesive, which is applied on substrate


12


to have an essentially uniform thickness and a coating density of about 2.0 to 3.0 oz/sq. yd. of pile fabric. For a more detailed discussion of adhesives and various additives which can be used for forming adhesive layer


14


, the reader is referred to U.S. Pat. No. 3,916,823 to Halloran, incorporated herein by reference.




Pile fibers


18


comprising pile layer


16


may similarly be comprised of a wide variety of natural and/or synthetic fibers according to the particular desired characteristics of pile fabric


10


. In a preferred embodiment, pile layer


16


is comprised of pile fibers


18


formed from a synthetic polymer material. In even more preferred embodiments, pile fibers


18


comprise nylon fibers. Fibers


18


for flocking may be natural in color or dyed, depending on the particular application, and pile layer


16


may be formed of pile fibers


18


which are all of the same color, thus forming a pile face


16


having a solid color, or from a plurality of pile fibers


18


having different colors, thus forming a pile face


16


that is multicolored. For use in the present invention, where a printed pattern is transferred to the pile fabric, it is preferred to use pile fibers of the same color or undyed pile fibers.




The length of pile fibers


18


, their denier, and the number density of the pile fibers on adhesive layer


14


can be varied over a relatively wide range and selected to yield a pile fabric having desirable characteristics for a particular application, as would be apparent to those of ordinary skill in the art. In one typical embodiment, pile fibers


18


can have an overall length between about 0.025 in and about 0.08 in (more preferably between about 0.04 in and about 0.065 in), a denier between about 0.45 and about 3.5, and an overall pile density of between about 1.0 to about 3.5 oz/sq. yd. of fabric. Pile layer


16


can be deposited on the adhesive coated substrate, as discussed in more detail below, by a variety of methods conventional in the art, including the use of flocked depositing equipment of the beater bar type, or electrostatic flocking equipment, such as described in more detailed in commonly-owned U.S. Pat. No. 5,108,777 to Laird incorporated herein by reference. A printed pattern may also be transferred to the flocked fabric by a variety of conventional techniques, including, but not limited to, screen printing, transfer paper printing, painting, air brush, etc., as apparent to those of ordinary skill in the art.





FIG. 2

illustrates a flocked fabric


20


that is typical of the fabric that has been air embossed utilizing air embossing systems and methods provided according to the invention. Pile layer


16


, comprising the embossable surface of fabric


20


, includes therein a plurality of air embossed features


22


. Air embossed features


22


are characterized by flattened or otherwise reoriented pile fibers. Adjacent to and separating embossed features


22


are unembossed portions


24


of the fabric surface, which are characterized by pile fibers


18


that extend essentially perpendicularly from adhesive layer


14


.




The orientation of pile fibers in the air embossed and unembossed portions of the fabric is seen more clearly in the cross-sectional view of

FIG. 2



b


.

FIG. 2



c


illustrates a similar embossed pile fabric


30


typical of that produced according to conventional prior art air embossing systems and methods. A comparison of the inventive air embossed fabric


20


and the conventionally air embossed fabric


30


illustrates several important distinctions. First, the inventive air embossed fabrics have embossed features wherein the smallest, most finely detailed embossed features have a characteristic dimension significantly less than that achievable with conventional systems and methods. For example, embossed fabric


20


, provided according to the invention, includes a smallest embossed feature


26


having a small characteristic dimension


28


. By contrast, the corresponding embossed feature


36


produced by a conventional system has a characteristic dimension


38


which is typically much greater. A “characteristic dimension” of an embossed feature, as used herein, refers to the smallest cross-sectional dimension of the feature, as measured from a first edge


27


of an unembossed portion of pile layer


16


across the feature to a second edge


29


of another unembossed region on the opposite side of the feature.




It can also be seen by comparing the larger embossed features of

FIGS. 2



b


and


2




c


that fabric


20


, provided according to the invention, has a significantly greater level of visual contrast between fibers in reoriented region


25


and the adjacent unembossed regions


24


of pile layer


16


, when compared to fabric


30


produced according to conventional air embossing technology. Specifically, the reoriented fibers in reoriented portion


25


are significantly more flattened onto the substrate in the inventive fabric


20


. In addition, distance


31


separating the flattened fibers of reoriented portion


25


and the essentially perpendicular fibers of an adjacent unembossed portion


24


can be very small and significantly less than the equivalent distance


37


of fabric


30


typically achievable using conventional air embossing technology. Thus, air embossed fabrics produced by air embossing systems and methods according to the invention can have an unprecedented level of fine detail and an unprecedented level of sharpness and visual contrast between embossed and unembossed portions of the pile fabric, yielding embossed patterns and visual effects previously unachievable by air embossing systems and producible only via utilization of more expensive roll embossing techniques.





FIG. 3

illustrates a preferred method according to the invention for forming and embossing a flocked pile fabric according to the invention. Embossed fabric production system


100


shown in

FIG. 3

, with the exception of the inventive modifications to air embossing system


109


described in detail below, can be essentially conventional in design and can be operated by methods well known to those of ordinary skill in the art. Such methods and systems for air embossing have been utilized extensively in the prior art and are described in more detail, for example, in U.S. Pat. No. 3,916,823 to Halloran. The process for producing an embossed pile fabric, for example similar to fabric


20


shown previously in

FIG. 2



a


, can proceed as described below. Roll


102


of a substrate


12


can be conveyed, in the direction indicated by arrow


105


, under tension from substrate roll


102


to take up roll


120


via conventional motor drive mechanisms for controllably driving one roll (i.e. take up roll


120


) or both rolls. The fabric can be guided and supported along the path of the process via a series of support rollers


104


. In other embodiments, instead of, or in addition to, conveying the fabric via motor-driven rotation of the take up roll/substrate roll, the fabric may be moved through the system via a conventional conveying system, such as a belt or apron conveyor. An adhesive layer is then applied to substrate


12


by a conventional adhesive applicator


106


, for example a roll coater, curtain coater, doctor blade, printing method etc. Typically, the adhesive is applied to the substrate by a doctor blade, although other methods such as printing, paint spraying and silk-screening may be used. In a preferred embodiment, an adhesive layer is applied to the entire upper surface of substrate


12


.




Substrate


12


, now coated with an adhesive layer, is then passed to flocking chamber


108


, which includes a pile applicator


110


. In flocking chamber


108


, as is conventional for producing flocked fabric, a layer of flocking formed by a multiplicity of fibers


18


is applied to the adhesive. Conventionally, and as hereinafter described, this deposition may be achieved by conventional beater bar or electrostatic techniques in which the ends of the pile fibers


18


adhere substantially to the adhesive layer. Pile fibers


18


, in preferred embodiments, are oriented essentially perpendicular to the adhesive layer. In some preferred embodiments, flocking chamber


108


may comprise an alternating current electrostatic flocking device having a variable frequency alternating electrostatic field that optimizes flocked fiber characteristics and processing efficiency, such as that described in co-owned U.S. Pat. No. 5,108,777 to Laird and incorporated herein by reference.




After application of a pile layer, the flocked substrate


111


is passed under air embossing cylinder


112


, which includes an air lance therein (shown and described in detail below) that is in fluid communication with pressurized air supply line


114


. As described in more detail below, air embossing cylinder


112


typically comprises a cylindrical screen or stencil having perforations and solid areas therein. Also as described in more detail below, pressurized air from air supply line


114


is directed by the air lance through the apertures or perforations in the cylindrical screen or stencil of embossing cylinder


112


, in order to form the embossed features within the pile layer of the fabric. An embossed pattern is formed by deflection of pile fibers


18


in the pile layer by air flowing through the apertures within the cylindrical screen or stencil of embossing cylinder


112


. Upon flowing through the apertures in the stencil of embossing cylinder


112


the air impinges upon pile fibers


18


and orients them in a direction that is dictated in part by the air velocity, direction of air flow, and size of the aperture in the stencil through which the air passes. In other words, those portions of the pile layer passing underneath apertures within the cylindrical stencil will become oriented to form the depressions in the embossed pattern, whereas those portions passing under solid areas of the stencil will not be subject to substantial air flow or reorientation of pile fibers


18


in the pile layer. As will be apparent to those of ordinary skill in the art, it is preferred that the adhesive layer be in a wet, uncured state during the air embossing procedure, such that the pile fibers


18


are not rigidly held by the adhesive and are able to have their position and orientation changed by an impinging air flow. The velocity of the air flow impinging upon the pile layer should be sufficient to exert a force on pile fibers


18


in order to create a desired degree of reorientation of the fibers.




After being embossed by embossing cylinder


112


, the pile fabric is passed through a curing chamber


116


in order to cure the adhesive layer so that the embossed pattern becomes permanently set. Curing chamber


116


may be comprised of any conventional curing equipment that exposes the embossed, but uncured, pile fabric to radiation to effect curing of the adhesive layer. Typical curing chambers operate by exposing the flocked fabric to a source of radiation, such as infrared radiation or heat, or ultraviolet radiation. In some preferred embodiments, curing chamber


116


comprises a gas-fired air dryer, as is well known in the art, that exposes the flocked fabric to a flow of heated air to enable convective drying and curing of the adhesive. After being cured, the embossed flocked fabric


118


exits the curing chamber and is wound onto take-up roll


120


. The speed at which the fabric is conveyed through air embossing system


100


can vary depending on a number of operating factors, as apparent to those of ordinary skill in the art. For some typical embodiments, the speed would be in the range of about, for example, 25 to 150 ft/min





FIGS. 4



a


-


4




c


show air embossing system


109


in greater detail. Air embossing system


109


comprises a modified version of a commercially available air embossing system (Aigle Equipment Model No. AP-1, Burgano Toninese, Italy). In alternative embodiments, the inventive features described herein may be utilized with other commercial available air embossing systems or may be integrated into a custom built and designed air embossing system, as would be apparent to those of ordinary skill in the art. Furthermore, it should be emphasized that any particular dimensions, sizes, materials, etc. described below for the illustrated embodiments of the invention are purely exemplary and are based upon the physical and operational constraints of the particular illustrated embodiment of air embossing system


109


. Other embodiments of the invention, employing alternative air embossing systems, may utilize equipment having different sizes and dimensions and employing different materials than specifically described herein. Accordingly, the particular sizes, dimensions, materials etc. described below are given purely for illustrative purposes and may be scaled, modified, or changed for application of the inventive features to alternative air embossing systems, as would be apparent to those of ordinary skill in the art.




Referring to

FIG. 4



a


, flocked, unembossed fabric


111


, is conveyed, as previously described, toward embossing cylinder


112


in the direction shown by arrow


122


. Embossing cylinder


112


includes a cylindrical central region, disposed above embossable surface


113


of unembossed fabric


111


, comprising a cylindrical stencil


128


, described in more detail below. Embossing cylinder


112


includes at each end thereof a reduced diameter stencil flange


130


(seen more clearly in

FIG. 5

) whereby it is attached to rotating bearings


132


of motorized drive unit


134


. Stencil flanges


130


are attached to rotating bearings


132


utilizing stencil mounting clamps


136


, which may be of any conventional design known to those of ordinary skill in the art. Motorized stencil drive unit


134


includes support structures


138


and


140


disposed on opposite sides of the width of fabric


111


. At least one of support structures


138


and


140


includes therein a variable speed motor (not shown) which powers a conventional drive mechanism to rotate stencil


128


with respect to fabric


111


. The drive mechanism for rotating the cylinder can be any suitable drive mechanism known in the art, including, but not limited to, belt-drive, gear-drive, friction and wheel-drive, inductive-drive, etc. mechanisms as apparent to those of ordinary skill in the arts. The drive mechanism of the illustrated embodiment comprises a gear-drive mechanism in which a variable speed motor (not shown) within support structure


140


rotates a gear (not shown) which, in turn, is engaged with a circumferential gear (not shown) comprising an outer surface of rotating bearing


132


within support structure


138


.




In the illustrated embodiment, the variable speed embossing cylinder drive motor can be operated to rotate cylinder


112


in the direction of arrow


143


(i.e., in a direction opposite that of the motion


122


of fabric


111


) or, more preferably, in the direction of arrow


142


(i.e., in the same direction as the direction


122


of fabric


111


).




In conventional prior art systems, embossing cylinder


112


is rotated in the direction of arrow


142


such that the speed of the surface of stencil


128


is essentially the same as the speed of fabric


111


passing under stencil


128


. In such conventional embodiments, the rotational speed of apertures


144


, within stencil


128


of embossing cylinder


112


, is matched to the speed of fabric


111


passing underneath, resulting in embossed features


22


in the air embossed fabric


118


having an overall length, as measured in the direction of motion


122


which is essentially the same as the overall length of the aperture


144


in stencil


128


, as measured along the direction of rotation


142


, which forms the embossed feature. By utilizing the variable speed motor drive provided according to the invention, stencil


128


can be rotated, in some embodiments, at speeds that are different than the speed of the fabric passing under the stencil, in order to create a variety of embossed patterns on the fabric, which each have a different visual appearance, with a single, given stencil.




For example, by rotating the stencil in direction


142


at a speed which is greater than that of the speed of the fabric passing under the stencil, the embossed features produced by: air passing through apertures


144


are shortened as measured along a direction parallel to the direction of motion


122


of the fabric when compared to an equivalent embossed pattern produced by a stencil rotating at the same speed as the fabric. In contrast, by rotating stencil


128


in a direction of arrow


142


at a speed which is less than the speed of the fabric passing under the stencil, embossed features


122


can be relatively lengthened and the level of detail visually evident in the embossed feature can be increased when compared to features produced with a stencil rotated at the same speed as the speed of the fabric. Thus, by changing the relative speed of the stencil with respect to the fabric, a variety of different patterns can be produced utilizing a single stencil. In some embodiments provided according to the invention, the speed of the fabric differs from the speed of the rotating stencil by at least a factor of about 2, and in other embodiments differs from the speed of the fabric by at least a factor of about 4.




One embodiment for embossing cylinder


112


is shown in greater detail in

FIG. 4



d


. Embossing cylinder


112


comprises a hollow cylinder having a centrally disposed stencil


128


defining an embossing region


146


, which extends across the width of the fabric to be embossed. In the illustrated embodiment, the embossing region is between about 54 inches and about 64 inches in length The embossing cylinder


112


, as illustrated, has a stencil region


128


having an outer circumference of about 25 inches. The inner diameter of stencil region


128


, in the illustrated embodiment, is about 7.95 inches, while the inner diameter of stencil flange


130


is about 5.5 inches.




Cylindrical stencil


128


can be conventionally formed from, for example, a cylindrical screen which has a series of solid, air impermeable regions


141


therein and a series of apertures


144


therein, which apertures permit air flow therethrough. Cylindrical stencil


128


can be formed in any manner conventionally used for forming such stencils. For example, in one embodiment, cylindrical stencil


128


can be formed using a well known lacquered screen process, where a cylindrical screen, typically constructed from a metal such as nickel, is coated with a lacquer. In forming the stencil, for such embodiments, the screen is first coated with an essentially uniform layer of lacquer, covered with a pattern template having regions that can block ultraviolet radiation, and exposed to ultraviolet radiation which tends to cure the lacquer. The regions of the screen beneath the pattern template regions that can block ultraviolet radiation will remain uncured after exposure and can be subsequently removed from the screen, thus leaving behind on the screen a lacquer coating, forming the stencil, having apertures therein with a pattern that is complementary to that of the pattern template. In another embodiment, the stencil can be formed by coating a metal screen with a patterned metallic layer using a Galvano process well known in the art. In yet other embodiments, cylindrical stencil


128


can be formed by directly covering a cylindrical screen with an air impermeable layer, such as a paper, plastic, or other air impervious layer, and then cutting out selected portions from the air impervious layer to form apertures


144


. It is to be understood, of course, that regions corresponding to apertures


144


may be cut out of the air impervious layer prior to utilizing the layer to form cylindrical stencil


128


. In other embodiments, cylindrical stencil


128


may be formed from a stencil typically employed for use in rotary screen printing operations or by any other methods apparent to those of ordinary skill in the art for forming air embossing stencils. Apertures


144


in cylindrical stencil


128


result in the formation of embossed depressions


22


in embossed fabric


118


as air passes through the apertures and impinges upon fabric


111


as it passes under embossing cylinder


112


. As is apparent in

FIG. 2



a


, the embossed depressions


22


formed by apertures


144


can typically have a similar overall shape and orientation as the apertures in cylindrical stencil


128


.




Referring again to

FIG. 4



a


, support structures


138


and


140


also include mechanisms thereon for holding and positioning an air lance (shown and described in detail below), which air lance is configured and positioned to direct a stream of air through apertures


144


in stencil


128


and onto fabric


111


to produce embossed features


22


in embossed fabric


118


. In

FIGS. 4



a


and


4




b


, in order to more clearly illustrate the air lance support and positioning mechanism, the air lance has been removed from the system and is not illustrated. When assembled for operation, the elongated air lance is inserted into aperture


148


in rotating bearing


132


such that it is disposed within embossing cylinder


112


, extends across the width of embossing cylinder


112


, and is supported by air lance inlet cradle


150


and air lance outlet cradle


152


(shown more clearly in

FIG. 4



b


) of system


109


. Aperture


148


, from which the inlet region of the air lance extends when installed in its operable configuration, has an internal diameter which is essentially equal to the internal diameter of stencil flange region


130


(i.e., about 5.5 inches as illustrated) of embossing cylinder


112


.




When configured for operation, the inlet region of the air lance is cradled and supported by air lance inlet cradle region


154


of air lance inlet support arm


150


. Preferably, air lance inlet cradle region


154


is sized and shaped such that it is complementary to the size and shape of the inlet region of the air lance so that the inlet region of the air lance rests snuggly and securely within the air lance cradle region, when the system is in operation.




Air lance inlet support arm


150


is pivotally attached to support structure


138


via spacer


156


and pivot bearing


158


so that the support arm can be pivoted up and down in the direction of arrows


160


in order to adjust the height of the air lance with respect to embossing cylinder


112


and in order to adjust the distance between the nozzle(s) in the air lance and the inside surface of stencil


128


, as described in more detail below.




Height adjustment of the air lance, supported by air lance inlet support arm


150


, is effected by air lance inlet height adjuster


162


. Height adjuster


162


comprises a main body


164


attached to the face of support structure


138


via mounting bracket


166


. Height adjuster


162


further includes a reciprocating piston


168


connected to the air lance inlet support arm


150


via a nut


170


on a threaded end thereof. In preferred embodiments, air lance inlet height adjuster


162


has a range of motion such that in a lower most position a nozzle of an air lance inserted into embossing cylinder


112


can contact the lowermost internal surface of the embossing cylinder, and an uppermost position providing a separation distance between the nozzle of the air lance and an internal surface of embossing cylinder


112


that is at least as great as the maximum separation distance desired during operation the system. In the illustrated embodiment, air lance inlet height adjuster


162


is pneumatically actuated via air line


172


to effect coarse up and down adjustment, and also includes a manually actuated fine height adjustment knob


174


, which is utilized by an operator to make fine height adjustments. The height adjuster also, if desired, can include a scale


176


, which can assist an operator to accurately and reproducibly position the inlet of the air lance.




Details of the mechanism provided on support structure


140


for positioning and supporting a mounting shaft of an air lance, which mounting shaft being positioned at the opposite end from the inlet of the air lance (shown more clearly in FIGS.


6


-


8


), is illustrated in

FIG. 4



b


. Air lance mounting shaft support arm


152


is similar in configuration to air lance inlet support arm


150


and is pivotally movable in order to adjust the height and position of the downstream end of the air lance via air lance downstream end height adjuster


178


which is essentially identical in design to inlet height adjuster


162


. Height adjuster


162


and height adjuster


178


, in preferred embodiments, are adjusted to create an essentially uniform distance between the nozzle(s) of the air lance and an adjacent internal surface of embossing cylinder


112


that is essentially uniform across essentially the entire width of stencil region


128


of embossing cylinder


112


. In other embodiments, however, the height adjusters may be differentially adjusted such that some nozzles of the air lance are closer to the stencil than others, or some portions of a given nozzle provided by the air lance are closer to the internal surface of the stencil than other portions.




As illustrated below in

FIGS. 6-8

, which show a variety of air lances provided according to the invention, the downstream ends of the illustrated air lances include mounting shafts having outer diameters which are typically less than the outer diameters of the main body portions and inlet regions of the air lances. The mounting shaft of the air lance is supported and positioned by air lance mounting shaft support clamp


180


which is mounted to support arm


152


via bolt and nut fasteners


182


. In the illustrated embodiment, mounting shaft support clamp


180


is mounted within a slot


184


on a platform region


186


of support arm


152


. This configuration allows mounting shaft support clamp


180


to be slidably movable in the direction of arrows


188


, in order to adjust the lateral position of the downstream end of the air lance within embossing cylinder


112


. In preferred embodiments, the lateral position of the mounting shaft support clamp is adjusted so that the nozzle(s) of the air lance is positioned such that it is bisected by center line


190


of embossing cylinder


112


.




Mounting shaft support clamp


180


also includes an angular adjustment set screw and knob


192


which can be utilized to adjust the angular orientation of the air lance within embossing cylinder


112


. Support clamp


180


also includes perpendicular alignment set screw


194


, which is mateable with an alignment hole (see

FIGS. 6-8

) within the mounting shaft of the air lance. When alignment set screw


194


is inserted into the alignment hole, it serves to fix the angular adjustment of the air lance so that the nozzle(s) is positioned to direct a stream of air essentially perpendicularly to the lowermost region of the internal surface of stencil


128


of embossing cylinder


112


(shown more clearly in

FIG. 5

below). In certain embodiments, set screw


194


may be turned out so that it does not project into aperture


196


of mounting shaft support clamp


180


, and the air lance may be positioned and secured utilizing angular adjustment set screw in knob


192


so as to position and secure the mounting shaft within aperture


196


at an orientation such that the nozzle(s) is not perpendicular and/or is not configured to direct an air stream essentially perpendicular to the lowermost internal surface of stencil


128


of embossing cylinder


112


. In certain such embodiments, the air lance may be positioned such that the air stream forms an angle of, for example, about 5 degrees to about 10 degrees with respect to center line


190


.





FIG. 4



c


illustrates a view of air embossing system


109


as seen by an observer positioned underneath fabric


111


. In preferred embodiments, system


109


includes a support surface


236


positioned directly beneath stencil


128


that is configured to support the underside of fabric


111


at a location where the adjacent embossable surface of the fabric is being impinged upon by an air stream emitted by the nozzle(s) of the air lance, when installed in the system during operation While in alternative embodiments to that illustrate in

FIG. 4



c


, the support surface may comprise a platform or other planar surface, it is preferred, as illustrated, that the support surface comprise a cylindrical, fabric support roller


104


.




In the illustrated embodiment, fabric support roller


104


is mounted on roller mounting arms


198


, which are supported by a roller support beam


200


. In some embodiments, roller mounting arms


198


may be configured so that the vertical position of fabric support roller


104


may be adjusted with respect to roller support beam


200


, fabric


111


and stencil


128


in the direction of arrows


199


. Fabric support roller


104


, in preferred embodiments, is configured to be rotated, most preferably in a direction of motion


201


co-directional to fabric


111


.




In the illustrated embodiment, fabric support roller


104


is driveably rotated via electric motor


202


and drive belt


204


located on motor support platform


203


. In alternative embodiments, as would be apparent to those of ordinary skill in the art, fabric support roller


104


may be rotated by a wide variety of alternative mechanical means. In the preferred embodiment illustrated, a surface cleaning element


206


is provided in contact with an external surface


236


of fabric support roller


104


. Surface cleaning element


206


serves to scrape off and remove any adhesive, pile fibers, or other debris which may collect on the surface


236


of fabric support roller


104


, thus eliminating or reducing any buildup of debris under the surface of fabric


111


during operation, which buildup in prior art systems typically limits the length of time the system can be operated without shutdown and cleaning of the support surface. In the illustrated embodiment, surface cleaning element


206


comprises a scraping blade positioned in contact with the outer cylindrical surface


236


of fabric support roller


104


along essentially the entire width of the fabric support roller positioned directly beneath stencil region


128


of embossing cylinder


112


. In the most preferred embodiments, the surface cleaning element is positioned to contact the support roller along substantially the entire length of the roller that is in contact with the underside of fabric


111


. Those of ordinary skill in the art will readily envision many other surface cleaning elements which may be utilized instead of scraping plate


206


, for example, brushes, air jets, water jets, etc., which are all deemed to be within the scope of the present invention.





FIG. 5

is a cross-sectional view of air embossing system


109


. For the purposes of illustration of the relative position of certain of the different elements of system


109


,

FIG. 5

illustrates a cross-sectional view of air embossing system


109


with one embodiment of an air lance provided by the invention installed within the system and with certain details of the surrounding support structures not illustrated for clarity.




Air lance


210


is similar in design to air lance


700


illustrated and discussed in greater detail in the context of

FIGS. 8



a


-


8




f


below. As discussed above, air lance


210


, when installed in operable engagement with air embossing system


109


, has an inlet region supported and positioned by air lance inlet support arm


150


and air lance inlet height adjuster


162


, and has a mounting shaft at its downstream end that is supported and positioned by air lance mounting shaft support arm


152


and air lance mounting shaft height adjuster


178


.




Air lance


210


illustrates one embodiment for an air lance which enables the nozzle(s) of the air lance to be positioned in close proximity to an internal surface of the stencil. Air lance


210


is shaped in the form of a tubular conduit and includes a main body portion


212


to which is attached a nozzle forming component


214


. Nozzle forming component


214


includes at its end a nozzle


216


and is shaped and positioned to enable the nozzle to be placed in very close proximity to surface


218


of the internal surface of stencil


128


, which surface


218


faces and is adjacent to the nozzle and is directly adjacent to fabric


111


.




As discussed in more detail below, in order to minimize pressure drop along the length of the air lance and in order to provide a desirable distribution of air flow within the air lance, main body portion


212


preferably is essentially uniform in diameter along the entire length of the air lance through which air flows, when the air lance is in operation. Accordingly, because of the physical constraints imposed by the air embossing system, conventional prior art air lances having nozzles formed directly in the side wall of the main body portion of the air lance and not including a nozzle forming component, such as nozzle forming component


214


, which projects and extends away from the side wall of the main body portion, cannot be positioned within the embossing cylinder so that the nozzle is in close proximity to the inner surface of the stencil.




The physical constraint of the air embossing system which prevents a nozzle formed directly in the side wall of a conventional air lance from being positioned in close proximity to the inside of the stencil is due to the difference in internal diameter of stencil


128


and the smallest internal diameter


219


of stencil flange


130


and aperture


148


of the air embossing system. As discussed previously, for a typical setup utilizing a stencil having a 25 inch outer circumference with a 7.95 inch internal diameter and having a flange having an internal diameter of about 5½ inches, a distance


220


of about 1.2 inches exists between the inner surface


222


of aperture


148


and stencil flange


130


and the inner surface


223


of stencil


128


. For conventional air lances without a nozzle forming component and having an inlet region having a diameter equal to or similar to the diameter of the main body portion, a nozzle formed in the side wall of the main body portion will be constrained by contact of the inlet portion of the air lance with surface


222


, which contact will prevent the nozzle from being able to be positioned from the internal surface


218


of stencil


128


by a distance that is significantly less than distance


220


.




Nozzle forming component


214


, which extends along a substantial fraction of the length of main body portion


212


but does not extend into the inlet portion of the main body, is able to bridge distance


220


to enable the nozzle


216


to be positioned as close to surface


218


of stencil


128


as desired. Nozzle forming component


214


, as described in more detail below in the context of

FIGS. 8



a


-


8




f


, preferably extends along the length of main body portion


212


across essentially the entire width of stencil


128


and fabric


111


, but does not extend into regions of the main body portion adjacent to internal surface


222


.




It is generally desirable to maximize the internal diameter of main body portion


212


in order to minimize any pressure drop along the length of air lance


210


, when the system is in operation. It is also required to size nozzle forming component


214


so that it extends from the external surface of main body portion


212


by a distance that enables nozzle


216


in the nozzle forming component to be positioned at a desirable distance from surface


218


of stencil


128


. Thus, nozzle forming component


214


is shaped and positioned to enable nozzle


216


to be separated from surface


218


by a distance that is substantially less than the distance separating outlet opening


224


in main body portion


212


, which outlet opening is in fluid communication with nozzle


216


, and surface


218


. “Substantially less than” when referring to the above discussed distance between nozzle


216


and surface


218


in comparison to the distance separating outlet opening


224


and surface


218


indicates that the distance separating nozzle


216


and surface


218


is no more than about 60% of the distance separating outlet opening


224


and surface


218


, and may, in some preferred embodiments, be less than 1% of the distance separating the outlet opening in the main body of the air lance and surface


218


of the stencil.




In the illustrated embodiment, main body portion


212


of air lance


210


comprises an aluminum conduit having a wall thickness of about ⅛ inch and an outer diameter of about 4 inches. In other embodiments, air lance


210


may be constructed of a variety of other materials, for example, other metals, plastics, etc. and may have a wall thickness different than that above, which is selected to provide sufficient resistance to operating pressure for the chosen material, as would be apparent to those of ordinary skill in the art. As discussed above, the main body portion


212


includes an outlet opening


224


therein, which is in fluid communication with nozzle forming component


214


. Outlet opening


224


may comprise a plurality of holes in the side wall of main body portion


212


; however, in more preferred embodiments such as that illustrated, outlet opening


224


comprises an elongated slot extending along a substantial portion of the length of the main body portion, as illustrated more clearly in

FIGS. 8



a


-


8




f


Main body portion


212


may also be stabilized against internal pressure by including one or more internal support struts


226


along its length, which can be welded or otherwise attached to main body portion


212


and can extend across outlet slot


224


in order to resist expansion of main body portion


212


when the air lance is in operation.




Typically, when in operation, the inlet of air lance


210


is attached to an air supply


114


, as shown above in

FIG. 3

, which preferably comprises a variable speed blower able to provide a user-adjusted volumetric flow rate of air to air lance


210


. Typical operating pressures within air lance


210


can range from about 1 inch H


2


O to about 100 inches H


2


O.




Nozzle forming component


214


may be formed of any suitable material, as would be apparent to those of ordinary skill in the art, and, in preferred embodiments is formed of a rigid metal. Nozzle forming component


214


spans outlet slot


224


of main body portion


212


and includes an upper curved surface


225


shaped to conform to the contour of the outer surface of main body portion


212


. Nozzle forming component


214


may be attached to main body portion


212


by any variety of means apparent to those of ordinary skill in the art. In the illustrated embodiment, nozzle forming component


214


is removably attached to main body portion


212


via a plurality of bolts


228


positioned along the length of the nozzle forming component on opposite sides of outlet slot


224


.




Nozzle forming component


214


, as illustrated, includes an internal chamber


230


therein which extends along the length of the nozzle forming component coextensive with nozzle


216


. Nozzle


216


can comprise a plurality of individual holes or ports within the lower surface of nozzle forming component


214


; however, in order to avoid artifacts caused by the air impermeable spaces between nozzles comprising individual apertures or orifices, in preferred embodiments, nozzle


216


comprises an elongated rectangular slit extending along a substantial fraction of the length of nozzle forming component


214


and across the width of stencil


128


and the embossable width of fabric


111


, when installed in the system.




In preferred embodiments, nozzle slit


216


extends along the length of nozzle forming component


214


so that it is co-extensive with outlet slot


224


in main body portion


212


and is aligned directly beneath and parallel with the outlet slot. In the illustrated embodiment, nozzle forming component


214


extends away from main body portion


212


so that nozzle


216


is separated from outlet opening


224


by a distance of about 1.25 inches, which is sufficient to span the entirety of distance


220


separating surface


218


and surface


222


, when the air lance is positioned in an operable configuration within the air embossing system. The illustrated combination, for example, of a 4 inch external diameter main body portion


212


and a nozzle forming component


214


that extends away from the main body portion by a distance by about 1.25 inches, results in an overall effective diameter


232


of air lance


210


that is just sufficient to clear smallest diameter


219


of stencil flange


130


and aperture


148


of the air embossing system.




It has been determined, according the invention, that by positioning nozzle


216


very close to surface


218


of stencil


128


, which is directly adjacent to fabric


111


, that the degree of collimation of air stream


231


, emitted from the nozzle, at the point where the stream passes through stencil


128


, is significantly enhanced over that of air streams emitted by conventional air lances at their point of passage through the embossing stencil. By reducing the distance separating nozzle


216


and surface


218


, the length of air stream


231


between its source at nozzle


216


and surface


218


is accordingly reduced, and the amount of dispersion of the air stream is significantly reduced or eliminated, resulting in the ability to achieve much finer levels of detail and an improved appearance of the embossed features of embossed fabric


118


. As described in much more detail below, the close proximity of nozzle


216


to surface


218


of stencil


128


combined with the ability of nozzle forming component


214


to effectively redirect airflow from a direction essentially parallel to longitudinal axis


320


of air lance


210


to a direction substantially perpendicular to the longitudinal axis enables air stream


231


to be directed in a direction that is much more perpendicular to the surface of fabric


111


than is achievable in conventional air lance designs.




As described previously in the context of

FIGS. 4



a


and


4




b


, the position of air lance


210


and the distance separating nozzle


216


from surface


218


of stencil


128


can be adjusted by an operator as desired via manipulation of height adjusters


162


and


178


. In addition, as previously described, the angular orientation of nozzle


216


with respect to center line


190


may be adjusted via angular adjustment set screw and knob


192


and perpendicular alignment set screw


194


(see in

FIG. 4



b


). As illustrated in

FIG. 5

, air lance


210


is positioned such that its alignment slot in its mounting shaft (see e.g.

FIGS. 8



a


-


8




f


) is engaged by alignment set screw


194


so that nozzle


216


is positioned along the center line


190


of stencil


128


so as to direct air stream


231


essentially perpendicular to surface


218


and the embossable surface


113


of fabric


111


. In preferred embodiments, nozzle


216


is positioned such that it is separated from surface


218


of stencil


128


during operation by a distance not exceeding about 0.75 inch, resulting in air stream


231


having a length between the nozzle


216


and surface


218


not exceeding about 0.75 inch. In other preferred embodiments, the distance separating nozzle


216


and surface


218


does not exceed about 0.5 inch, in other embodiments does not exceed about 0.25 inch, in yet other embodiments does not exceed about 0.1 inch, in other embodiments does not exceed about 0.05 inch, in yet other embodiments does not exceed about 0.025 inch, in other embodiments does not exceed about 0.0125 inch, and in yet other embodiments does not exceed about 0.01 inch.




In addition, it is preferred to adjust the vertical position of fabric support roller


104


and fabric


111


such that the upper most surface


113


of pile layer


16


is separated from external surface


233


of stencil


128


, which surface


233


is directly adjacent internal surface


218


and is positioned directly above pile layer


16


, by a distance not exceeding about 0.02 inch. In other embodiments, fabric facing surface


233


of stencil


128


is positioned from the embossable-surface of pile layer


16


by a distance not exceeding about 0.01 inch, in other embodiments by a distance not exceeding 0.005 inch, and yet in other embodiments by a distance not exceeding about 0.001 inch. Thus, it is desirable that the distance between surface


233


and pile layer


16


be very small but without surface


233


actually making physical contact with pile layer


16


, which would tend to distort the pile air and create undesirable visual artifacts.




Also, as illustrated in

FIG. 5

, it is preferred that support surface


236


of fabric support roller


104


be positioned such that its upper most surface


238


is aligned with center line


190


such that surface


238


is positioned directed beneath and space apart from nozzle


216


such that air stream


231


exiting the nozzle is directed to impinge upon fabric


111


at a location


241


where the fabric is adjacent to and in contact with support surface


236


. This configuration prevents the fabric from being pushed away from the embossing surface of stencil


128


by air stream


231


and maintains the desired distance between stencil


128


and pile layer


16


of embossable fabric


111


.




Another way to improve the degree of collimation of air stream


232


and the ability of air lance


210


to produce fine embossed detail and desirable embossing performance is to substantially reduce the characteristic orifice dimension of nozzle


216


in comparison to characteristic orifice dimensions of nozzles in conventional air lances. A “characteristic orifice dimension” of a nozzle, as used herein, refers to the smallest cross-sectional dimension of the nozzle. In the illustrated embodiment, where nozzle


216


comprises an elongated rectangular slit, the characteristic orifice dimension


240


comprises the width of the elongated slit forming nozzle


216


. For embodiments wherein the nozzles comprise circular holes, the characteristic dimension of each nozzle would be the diameter of the circular hole forming the nozzle. Similarly, for other shapes, the characteristic dimension can be determined by measuring the smallest cross-sectional dimension of the particular shape comprising the nozzle (e.g., for a nozzle comprising an ellipse, the characteristic orifice dimension would comprise the length of the minor axis of the ellipse). In preferred embodiments, the characteristic orifice dimension of the nozzles of air lances provided according to the invention is less than about 0.2 inch. In other preferred embodiments, the characteristic orifice dimension of the nozzle does not exceed about 0.1 inch, in other embodiments does not exceed about 0.05 inch, in yet other embodiments does not exceed about 0.01 inch, in other embodiments does not exceed about 0.005 inch, and in yet other embodiments does not exceed about 0.001 inch.




In addition to increasing the degree of collimation of air stream


232


, by reducing the characteristic dimension of the nozzles of the air lances provided by the invention, the total amount of open area of the nozzles, through which the air stream passes, is a much smaller fraction of the cross-sectional internal area of the main body portion of the air lance supplying air to the nozzle. Thus, the inventive air lances, having nozzles with small characteristic orifice dimensions, generally have a much higher fraction of the total resistance to air flow provided by the nozzle(s) than is typical for conventional prior art air lance designs. In preferred embodiments, the total open area provided by the nozzle(s) of the air lances provided by the invention does not exceed about 15% of the internal cross-sectional area of the main body portion of the air lance. In other preferred embodiments the nozzle area does not exceed about 7.5%, in other embodiments does not exceed about 1.5%, and in yet other embodiments does not exceed about 0.1% of the total open cross-sectional area of the main body portion of the air lance.




By designing the inventive air lances so that most of the resistance to air flow is provided by the nozzle(s), the pressure drop along the length of the air lance can be substantially reduced, and the air flow emitted from the nozzle(s) along the length of the air lance can be much more evenly distributed than in conventional air lance designs. In some preferred embodiments, by employing a nozzle(s) with a very small characteristic orifice dimension, the air flow velocity through the nozzle(s) of the air lance can be substantially constant along the portion of the length of the air lance along which the nozzle(s) is positioned. This uniformity of air flow velocity emitted from the air lance along its length can result in a high degree of uniformity in the embossed pattern across essentially the entire width of fabric


111


.




It is also desirable, according to the invention, to supply a sufficient flow of air to the inlet of the air lance to create a stream of air emitted from the nozzle(s) having an air flow velocity of at least about 12,000 feet per minute. In other preferred embodiments, sufficient air flow is supplied so that the velocity of air exiting the nozzle(s) of the air lance is at least about 15,000 feet per minute, in other embodiments at least about 20,000 feet per minute, and in yet other embodiments at least about 25,000 feet per minute. Such air flow velocities are substantially higher than those employed or achievable by conventional prior art air embossing systems and enable the inventive system to produce extremely finely detailed embossed patterns. The air flow velocity through the nozzle(s) of the air lances according to the invention can be easily determined by an operator of the system based upon the total open area of the nozzle(s), a measured inlet pressure of the air supply to the air lance, and performance charts typically supplied by the manufacture of the air blower utilized to supply is air to the air embossing system. Such measurements and determinations are routine for those of ordinary skill in the art.





FIG. 6



a


illustrates an alternative embodiment of an air lance, according to the invention. Air lance


300


, as shown in

FIG. 6



a


, has a nozzle region


302


of main body portion


304


positioned so that it is facing the observer.

FIG. 6



b


shows air lance


300


in a side view. Air lance


300


comprises a conduit having a main body portion


304


and includes an inlet opening


306


and a threaded inlet connector


308


, allowing attachment of the air lance to air supply line


114


of the air embossing system when it is in operation. Main body portion


304


is essentially constant in diameter along its entire length. Main body portion


304


includes an inlet region


310


upstream of nozzle region


302


and may, optionally, include a small end region


312


downstream of nozzle region


302


and upstream of sealed end


314


of the main body portion. In alternative embodiments, air lance


300


, or any other air lance illustrated herein, may, instead of having a single inlet opening for attachment to the air supply, have each of its ends open for fluid communication and attachable to an air supply. Affixed to downstream end


314


of main body portion


304


is mounting shaft


316


including an alignment slot


318


(seen most clearly in

FIG. 6



b


), which mounting shaft typically has a diameter that is smaller than the diameter of main body portion


304


.




When mounted in an operable configuration within air embossing system


109


, inlet region


310


is disposed upon air lance inlet cradle


154


(see

FIG. 4



a


) such that at least inlet connector


308


extends beyond air lance inlet support


150


, so as to be easily connectable to air supply line


114


. Air lance


300


is disposed within embossing cylinder


112


and extends across the entire width of the embossing cylinder so that mounting shaft


316


is disposed within air lance mounting tube support clamp


180


of the air embossing system (see

FIG. 4



b


), when the air lance is configured for operation. Typically, for preferred embodiments where it is desired that nozzle region


302


be positioned so that it is bisected by center line


190


of embossing cylinder


112


, alignment slot


318


is configured to be engageable, when the air lance is in the above-described mounting position, with perpendicular alignment set screw


194


, thus allowing the perpendicularly aligned position of the nozzle to be easily ascertained and securely maintained during operation.




Nozzle region


302


of air lance


300


extends along main body portion


304


in a direction essentially parallel to longitudinal axis


320


of the air lance so that it is located within, and is essentially coextensive with, the width of stencil region


128


of embossing cylinder


112


, when the air lance is installed in an operable configuration. Accordingly, nozzle region


302


is also configured to extend across essentially the entire width of the embossable surface


113


fabric


111


, when in operation.




In the embodiment illustrated, nozzle region


302


is about 54 inches to about 64 inches in length, inlet region


310


is about 24 inches to about 28 inches in length, end region


312


is about 1 inch to about 4 inches in length, and mounting shaft


316


is about 13 inches to about 15 inches in length and is about 2 inches to about 3 inches in outer diameter.




Nozzle region


302


includes therein a plurality of individual nozzles


324


, which, in the illustrated embodiment comprise a plurality of circular holes within main body portion


304


. In the illustrated embodiment, nozzles


324


comprise holes bored directly into the side wall of main body portion


304


; however, in alternative embodiments, nozzles


324


may be formed in a separable plate element, which is attachable by screws or other fasteners to main body portion


304


. Also, in other embodiments, the holes


324


comprising the nozzles may be arranged of positioned differently within nozzle region


302


than that shown. For example, in one alternative embodiment, the nozzles may be arranged in a single row within the nozzle region.




Because nozzle region


302


, in the illustrated embodiment, includes nozzles


324


comprising of a plurality of individual holes separated by regions


325


of main body portion


304


, which regions


325


are impermeable to air flow, it is preferred that nozzle region


302


be separated from inner surface


218


of stencil


128


(see

FIG. 5

) by at least about 0.75 inch. In the illustrated embodiment, since the outer diameter of main body portion


304


is essentially constant (typically about 4 inches to about 5¼ inches), as previously discussed in the context of

FIG. 5

, it is not possible to position nozzles


324


any closer to inner surface


218


of stencil


128


than distance


120


(e.g., about 1.2 in, as illustrated). In order to reduce dispersion when nozzles


324


are separated by such relatively large distances, main body portion


304


preferably includes flaps


326


installed on each side of nozzle region


302


. The flaps are preferably flexible, so that they do not prevent insertion of the air lance through the flanged region


130


of the embossing cylinder


112


, and so that after insertion into the embossing cylinder, they extend downward from main body portion


304


by a distance preferably approximately equal to the distance separating nozzles


324


from the internal surface of the stencil region of the embossing cylinder.




In order to improve the collimation of air flow from nozzles


324


and the distribution of air velocity along the length of nozzle region


302


, it is preferred that nozzles


324


have a characteristic dimension, characterized by the diameter of the holes comprising nozzles


324


, that does not exceed about 0.2 in, as was discussed above in the context of air lance


210


illustrated in FIG.


5


. In other preferred embodiments, the characteristic dimension of nozzles


324


does not exceed about 0.1 in, in other embodiments does not exceed about 0.05 in, in yet other embodiments does not exceed about 0.01 in, in other embodiments does not exceed about 0.005 in, and in yet other preferred embodiments does not exceed about 0.001 in.




Air lance


300


is shown in cross section in

FIG. 6



c


. Nozzle region


302


is shown magnified in figure insert


328


of

FIG. 6



c


.

FIG. 6



c


illustrates one preferred embodiment for providing nozzles


324


having a characteristic nozzle length


330


which exceeds the characteristic orifice dimension


332


of the nozzle. In the illustrated embodiment, characteristic nozzle length


330


is essentially equal to the wall thickness of main body portion


304


. Thus, in the embodiment illustrated in

FIG. 6



c


, it is preferred that the diameter of nozzles


324


be no greater than, and preferably less than, the wall thickness of main body portion


304


. In general, the “characteristic nozzle length,” as used herein in the context of the air lances provided according to the invention, refers to the maximum dimension of the nozzle as measured in a direction that is essentially parallel to the overall direction of air flow within the nozzle (i.e., in a direction that is typically essentially perpendicular to the longitudinal axis of the air lance). By providing nozzles having a characteristic nozzle length that exceeds the characteristic orifice dimension of the nozzle, the inventive air lances can significantly reduce the proportion of the air stream that is emitted from the nozzle in a diagonal direction with respect to the inner surface of the stencil, the surface of the fabric, and the longitudinal axis of the air lance. For an embodiment where the nozzles are in the form of circular holes having characteristic nozzle lengths approximately equal to the diameter of the holes forming the nozzle, it is apparent that essentially the entire stream of air directed towards the inner surface of the stencil through each nozzle will be directed through the nozzle at an angle of at least about 45 degrees with respect to the longitudinal axis of the air lance, when the system is in operation Any component of the air stream forming an angle less than 45 degrees with respect to the longitudinal axis will impinge upon a sidewall (e.g., walls


333


shown in

FIG. 6



c


) and will be deflected towards the surface of the stencil at an angle with respect to the longitudinal axis of the air lance of at least about 45 degrees. In even more preferred embodiments, the characteristic length


332


of nozzles


324


exceeds the characteristic orifice diameter


332


by at least a factor of about 2, in more preferred embodiments by at least a factor of about 3, and in the most preferred embodiments, by at least a factor of about 4.





FIG. 6



d


and

FIG. 6



e


show cross sectional views of an alternative embodiment of air lance


300


that includes a plurality of air redirecting elements


340


that are shaped and positioned to intercept and deflect the air flow within main body portion


304


so that a greater fraction of the air flow is directed essentially perpendicular to longitudinal axis


320


and to the embossable surface


113


of fabric


111


, when the air embossing system is in operation. As discussed above, in preferred embodiments, air directing elements


340


preferably intercept and direct the air flow so that essentially all of the air flow exits from nozzles


324


toward the fabric in a direction making an angle of at least about 45 degrees with respect to longitudinal axis


320


of the air lance. Air redirecting elements


340


comprise a series of baffles that may be formed of a wide variety of materials and may comprise a variety of structures able to: deflect and redirect air flow. An “air redirecting element”, “air flow redirecting element,” or “baffle” as used herein refers broadly to any element positioned within an air lance, which is shaped, positioned, and configured such that at least a portion of the flow of air supplied to the air lance impinges upon and is redirected by the element from an initial air flow direction forming an angle of less than about 45 degrees with respect to the longitudinal axis of the air lance to a subsequent air flow direction forming an angle greater than about 45 degrees with respect to the longitudinal axis of the air lance.




In the embodiment illustrated in

FIGS. 6



d


and


6




e


, air flow redirecting elements


340


comprise a plurality of tubular inserts positioned within outlet openings


341


of main body portion


304


. Air redirecting elements


340


have an outer diameter that is equal to or slightly less than the diameter of outlet openings


341


, such that they may fit snuggly and securely within outlet openings


341


, when installed as shown in

FIG. 6



d


. Air redirecting elements


340


can, in some embodiments, be press fit into outlet openings


341


or, for improved stability, may be welded to main body portion


304


, once they are inserted into outlet openings


341


. Alternatively, air redirecting elements


340


may be welded, or otherwise attached within main body portion


304


adjacent and in fluid communication with outlet openings


341


, without actually being inserted into the outlet openings.




Nozzles


324


, as illustrated, have a characteristic orifice dimension


342


essentially equal to the internal diameter of air directing elements


340


and have a characteristic nozzle length


344


essentially equal to the length of air directing elements


340


, as measured in a direction perpendicular to longitudinal axis


320


of the air lance. In alternative embodiments, air directing elements


340


, instead of being press fit within outlet openings


341


of main body portion


304


, may have an inner diameter equal to or greater than the diameter of outlet openings


341


and may be attached to an inner surface of main body portion


304


above outlet openings


341


, as described above, such that the characteristic nozzle length comprises the sum of the wall thickness of main body portion


304


plus the length of an air redirecting element


340


, as measured along a direction perpendicular to longitudinal axis


320


. In such alternative embodiments, it is preferred that a substantial fraction of both (i.e., at least 50%) of the characteristic length of the nozzle be comprised of the length of the air redirecting element, as measured in a direction essentially perpendicular to the longitudinal axis of the main body.




Referring again to the embodiment shown in

FIGS. 6



d


and


6




e


, in preferred embodiments, the length


344


of air redirecting elements


340


, as measured in a direction that is essentially perpendicular to longitudinal axis


320


, exceeds characteristic orifice dimension


342


of nozzles


324


by a factor of at least about 2, more preferably a factor of at least about 3, and most preferably by a factor of at least about 4.





FIGS. 6



f


and


6




g


illustrate a cross-sectional view of another alternative embodiment of air lance


300


including a main body portion


304


including therein a single, monolithic air redirecting element


350


. A “monolithic” air redirecting element, as used herein, refers to an air redirecting element having a plurality of surfaces for redirecting or deflecting air, wherein the surfaces are formed within a single, undivided piece of material, or comprise a plurality of physically distinct elements that are interconnected together so as to form a continuous structure. Air redirecting element


350


is preferably positioned within main body portion


304


and attached to an internal surface of the main body portion by welded attachments, or other means of fastening, as would be apparent to those of ordinary skill in the art. Air redirecting element


350


has an overall width and length sufficient to essentially completely cover and be coextensive with nozzle region


302


of air lance


300


. Air redirecting element


350


performs an essentially equivalent function as that previously described for air redirecting elements


340


in the context of

FIGS. 6



d


and


6




e


above. Air redirecting element


350


can comprise a wire or fabric mesh, screen, grate, or any other suitable structure, as would be apparent to those of ordinary skill in the art. Air redirecting element


350


, as illustrated in

FIG. 6



g


, can comprise a grate-like structure having a plurality of cells


352


, which form air flow channels that are oriented essentially perpendicularly to longitudinal axis


320


of the air lance. Cells


352


are separated one from another by a series of walls of structure


350


forming dividers


354


. Distance


356


, is the characteristic dimension of channels


352


. In general, the “characteristic dimension” of a channel in a monolithic air redirecting element, as used herein, is defined as the largest cross-sectional dimension of the channel as measured along a direction essentially parallel to the longitudinal axis of the air lance.




The monolithic baffle


350


illustrated in

FIGS. 6



f


and


6




g


has channels


352


comprising a plurality of square conduits arranged in a grid pattern However, in alternative embodiments, the monolithic air redirecting element may have channels comprising a plurality of cells having cross-sectional shapes other than square. In one preferred embodiment, monolithic air redirecting element


350


comprises a honeycomb-like structure, described in more detail below in the context of

FIG. 9

, having a plurality of hexagonally shaped cells arranged in a honeycomb-like pattern.




In preferred embodiments, the height


358


of air redirecting element


350


, as measured in a direction essentially perpendicular to the longitudinal axis of the air lance, exceeds characteristic dimension


356


by a factor of at least about 2, more preferably by a factor of at least about 3, and most preferably by a factor of at least about 4. Air redirecting element


350


, when it is constructed and positioned as shown in

FIGS. 6



f


and


6




g


functions to increase the fraction of air flow through nozzles


324


that is directed essentially perpendicularly to the longitudinal axis


320


of the air lance and essentially perpendicularly to the surface of the fabric being embossed, when the air embossing system is in operation. In other words, the monolithic air redirecting elements provided in the embodiment illustrated in

FIGS. 6



f


and


6




g


, and in other embodiments of the inventive air lances described below, increase the fractional amount the stream of air directed through apertures or openings in the stencil of the air embossing system that is oriented in a direction essentially perpendicular to the embossable surface of the fabric being embossed, when the air lance is in operation, when compared to the fractional amount of a stream of air directed through the openings in the stencil essentially perpendicular to the embossable surface of the fabric by an essentially equivalent air lance, but without the air redirecting element included therein.




Air lance


500


illustrated in

FIGS. 7



a


-


7




d


represents an alternative, although less preferred, embodiment for providing certain of the benefits of air lance


220


, discussed above in the context of

FIG. 5

, and air lance


700


, discussed below in the context of

FIGS. 8



a


-


8




f


. Specifically, air lance


500


is configured to provide a nozzle that can be positioned in close proximity to the internal surface of an embossing stencil and in close proximity to the surface of an embossable fabric. Air lance


500


, when installed in air embossing system


109


similarly to the installation shown previously for air lance


220


in

FIG. 5

, can be positioned with respect to interior surface


218


of stencil


128


(see

FIG. 5

) so that its nozzle


502


is positioned from surface


218


at a distance that is less than distance


220


defining the overhang distance between the internal surface of the stencil and the internal surface of the embossing cylinder in flange region


130


(or the internal surface of aperture


148


of air embossing system


109


, whichever creates a larger overhang distance


220


). Nozzle


502


may be positioned at distances with respect to surface


218


that are similar to the preferred distances separating surface


218


and nozzle


216


of air lance


210


described above in the context of FIG.


5


.




Air lance


500


comprises a main body portion


504


including, in preferred embodiments, a single, slit-shaped nozzle


502


extending along a substantial fraction of the length of main body portion


504


and defining nozzle region


506


. In alternative, less preferred, embodiments, the air lance may include a plurality of nozzles comprising individual holes instead of a single, slit-shaped nozzle. As discussed above for air lances


210


and


300


, the nozzle region preferably extends across essentially the entire width of embossing cylinder stencil region


128


and embossable surface


113


of fabric


111


, when the air lance is positioned within air embossing system


109


for operation.




Nozzle


502


, in preferred embodiments, has a characteristic orifice dimension, defined by width


508


of the slit, that is less than about 0.2 inch and preferably falls within the preferred range discussed above for nozzle


216


of air lance


210


. In the illustrated embodiment, slit width


508


is essentially constant along the entire length of nozzle region


506


. In alternative embodiments, slit


502


may be tapered so that slit width


508


changes along the length of the nozzle. For example, in some such embodiments, slit


502


may be wider at the end of the nozzle nearest offset inlet tube


510


than at the end nearest offset mounting shaft


512


. Such a configuration, especially for nozzles having relatively large characteristic orifice dimensions, may improve the uniformity of air flow velocity along the length of nozzle region


506


.




Referring now to

FIG. 7



b


, a side view of air lance


500


shows that inlet tube


510


and mounting shaft


512


have centers that are offset with respect to longitudinal axis


320


of the air lance. Inlet tube


510


also has a smaller diameter than main body portion


504


of air lance


500


. Providing a reduced diameter inlet tube, which is offset with respect to longitudinal axis


320


, enables the provision of an overhang region


514


, which enables nozzle


502


to be positioned within embossing cylinder


112


so that it is able to be placed in a desirably close proximity to the internal surface


218


of stencil


128


(see FIG.


5


). For embossing cylinders and embossing systems having the dimensions and configuration described previously in the context of

FIGS. 4 and 5

, air lance


500


can be configured, as in the illustrated embodiment, with a main body portion


504


having an outside diameter of about 5¼ inches, and having an offset inlet tube, as illustrated, having an outside diameter of no more than about 2.8 inches. This configuration provides an overhang distance


514


of at least about 1.2 inches, sufficient to completely traverse distance


220


shown above in FIG.


5


.




It is to be understood that for embodiments of an air embossing system utilizing an air lance similar to air lance


500


, inlet tube


510


will need to be of sufficient length so that upstream surface


518


of main body portion


504


is positioned within embossing cylinder


112


so that it is completely contained within the large internal diameter portion of the embossing cylinder, when configured for operation. Also, air lance inlet support arm


150


of air embossing system


109


(see

FIG. 4



a


) should be configured so that air lance inlet cradle


154


is shaped and sized to conform to the smaller size of inlet tube


510


of air lance


500


.




A cross-sectional view of a preferred embodiment of air lance


500


is shown in

FIGS. 7



c


and


7




d


. Preferably, in order to maintain a constant characteristic orifice dimension upon pressurization of air lance


500


during operation, main body portion


504


is stabilized by one or more support struts


226


, as described above in the context of air lance


210


in FIG.


5


. In addition, preferred embodiments of air lance


500


, the lance also includes a monolithic air redirecting element or baffle


520


that can be essentially similar in configuration and function to air redirecting element


350


described above in the context of

FIGS. 6



f


and


6




g.






For embodiments where nozzle


502


is positioned in close proximity to the internal surface of the embossing stencil (e.g., at distances of less than about 0.75 inch) it is preferred that the thickness of the walls or dividers


522


of structure


520


separating each of the cells or channels


524


be less than the characteristic orifice dimension of nozzle


502


. It has been found, in the context of the present invention, that if wall thickness


522


exceeds the characteristic orifice dimension of nozzle


502


that undesirable, visually apparent artifacts may be created in the embossed pattern of a fabric embossed using the air lance. Accordingly, in preferred embodiments, it is preferred that the thickness of walls


522


of structure


520


be less than, and preferably substantially less than, the characteristic orifice dimension of nozzle


502


. In the most preferred embodiment, the thickness of walls


522


is preferably minimized such that it is as small as possible, while maintaining the structural integrity of baffle


520


in operation. For aluminum honeycomb-like structures, such as baffle


800


shown in

FIG. 9

, it is preferred that the thickness of the walls not exceed about 0.002 inch. In other embodiments, the wall thickness of walls forming a monolithic baffle comprising an aluminum honeycomb-like structure may be as small as about 0.001 inch or less.





FIGS. 8



a


-


8




f


illustrate a preferred embodiment of an air lance


700


essentially similar in configuration to air lance


210


described previously in the context of

FIG. 5

, except including a nozzle forming component


702


configured to contain one or more air redirecting elements or baffles therein. Elements which are essentially identical to those described previously for air lance


210


are labeled in

FIGS. 8



a


-


8




f


using the same figure labels. Similarly, and as with air lance


500


of

FIGS. 7



a


-


7




d


, components essentially equivalent to or similar to those illustrated and discussed in the context of air lance


300


shown in

FIGS. 6



a


-


6




g


are also labeled with the same figure labels as those used in

FIGS. 6



a


-


6




g.






Referring to

FIG. 8



a


, nozzle forming component


702


includes, machined therein, a nozzle slit


216


, which extends along the majority of its length except for regions


703


and


705


at its upstream and downstream ends respectively. Nozzle forming component


702


preferably is sized so that it projects beyond an outermost surface


707


(see

FIG. 8



b


) of main body portion


212


by a distance


709


that is equal to or greater than distance


220


shown and discussed above in the context of

FIG. 5

, thus, enabling nozzle


216


to be positioned as close to surface


218


of stencil


128


as is desired during operation.




Nozzle slit


216


can be formed in nozzle forming component


702


by a variety of conventional machining methods, as would be apparent to those of ordinary skill in the art, including, but not limited to, cutting with a blade, water jet cutting, laser cutting, etc. For embodiments involving extremely narrow slits, for example nozzles having a characteristic orifice dimension less than about 0.02 inch, nozzle forming component


702


, instead of being formed of a unitary, monolithic structure having slit


216


machined therein, may instead comprise two separable components, each separable component being mounted on opposite sides of outlet opening


224


of main body portion


212


(see

FIG. 8



c


) such that they are positioned adjacent and separated from each other on the main body portion, for example by the use of very thin shim(s) or spacer, so that the distance between the adjacent facing surfaces of the two components defines a slit forming a nozzle having a characteristic nozzle orifice dimension essentially equal to the width of the shim(s) or spacers utilized to separate the two subcomponents of the nozzle forming component during mounting to the main body portion. In addition, as discussed previously for the prior air lances provided according to the invention, air lance


700


includes a nozzle region


704


, having a length defined by the length of nozzle


216


, which nozzle region extends across essentially the entire width of stencil


128


and embossable surface


113


of embossable fabric


111


, when air lance


700


is positioned within air embossing system


109


for operation.





FIG. 8



c


presents a cross-sectional view of air lance


700


illustrating one preferred embodiment for providing an air redirecting element


800


within nozzle forming component


702


. Nozzle forming component


702


includes a hollow chamber


708


therein for containing air directing element


800


and further includes, downstream of hollow chamber


708


, a tapered chamber


710


, which serves to further direct and focus air flow within the nozzle forming component toward slit nozzle


216


. Main body portion


212


includes an outlet opening


224


comprising an elongated slot disposed along the length of the main body portion essentially coextensive with and parallel to slit nozzle


216


. Hollow chamber


708


and tapered chamber


710


extend along the length of nozzle forming component


702


so that they are essentially coextensive with slit nozzle


216


and elongated slot


224


in main body portion


212


.




Air redirecting element


800


, in the illustrated embodiment, comprises a monolithic aluminum honeycomb-like structure, shown in more detail in FIG.


9


and discussed above in the context of

FIGS. 6 and 7

. As shown most clearly in

FIG. 8



d


and

FIGS. 9



a


and


9




b


, air redirecting element


800


comprises a plurality of hexagonally shaped cells


802


with a characteristic dimension


804


and a height


806


. In one embodiment, air redirecting element


800


comprises an aluminum honeycomb structure including a plurality of hexagonally shaped cells


802


each having a characteristic dimension of about ⅛ inch and a height of about ½ inch. Preferably, as discussed previously with respect to monolithic air redirecting elements


520


and


350


, the thickness of the walls


808


of the structure separating cells


802


is less than the characteristic orifice dimension of nozzle


216


. In one illustrative embodiment, the thickness of walls


808


is about 0.002 inch, and in another illustrative embodiment, the thickness is about 0.001 inch




Referring again to

FIG. 8



c


, hollow chamber


708


preferably is sized and shaped to snuggly accommodate monolithic air redirecting element


800


in order to prevent vibration and motion of the air redirecting element during operation of the air lance. For added stability, in some embodiments, air redirecting element


800


may be welded, or otherwise affixed to one or more internal surfaces of hollow chamber


708


in order to further prevent motion of the element during operation. As illustrated in

FIG. 8



c


, hollow chamber


708


is preferably located within nozzle forming component


706


so that air redirecting element


800


is positioned as far upstream of nozzle


216


as possible. Positioning air redirecting element


800


as far upstream as possible from nozzle


216


further acts to reduce potential artifacts within an embossed pattern of a fabric, which artifacts may be due to the presence of walls


808


separating the cells


802


of the air redirecting element.




Air redirecting element


800


is preferably installed in hollow chamber


708


so that channels


802


formed by the cells of the structure of the monolithic air redirecting element are aligned so that they are essentially perpendicular to longitudinal axis


320


of main body portion


212


. In operation, air redirecting element


800


serves to redirect and deflect air flow within main body portion


212


so that a greater fraction of air flow emitted from nozzle


216


is directed essentially perpendicularly to longitudinal axis


320


and embossable surface


113


of fabric


111


, as compared to that emitted from an essentially equivalent air lance but without air redirecting component


800


installed therein. It should be emphasized, that for embodiments involving air lances provided according to the invention utilizing nozzle forming components (e.g., air lance


210


shown in FIG.


5


and air lance


700


shown in

FIG. 8

) utilization of an air redirecting element is optional and may not be required, under some operating conditions, in order to yield desirable embossing performance, especially, for example, when using air lances with nozzles having a very small characteristic orifice dimension, for example, less than about 0.1 inch.




An alternative embodiment of air lance


700


providing a plurality of air redirecting elements is illustrated in the cross sectional views of

FIGS. 8



e


and


8




f


. Nozzle forming component includes a hollow chamber


758


therein that contains a plurality of air redirecting elements


760


comprising a series of baffling vanes disposed along essentially the entire length of chamber


758


and spaced apart from each other at regular intervals defined by distance


762


. Vanes


760


are preferably oriented within chamber


758


so that an air deflecting surface


764


of each vane is essentially perpendicular to longitudinal axis


320


of main body


212


. As shown in

FIG. 8



f


, nozzle forming component


756


preferably includes a plurality of spaced grooves


766


in sidewall


768


of chamber


758


for positioning and securing the edges of vanes


760


therein. Grooves


766


should have a width that is essentially equal to or slightly less than thickness


770


of vanes


760


, such that when inserted into grooves


766


vanes


760


are essentially immobilized during operation of the air lance. In alternative embodiments, nozzle forming component


756


may include a chamber not including vane-mounting grooves therein, and the vanes may instead be secured to the sidewall of the chamber by welding or other affixing means, as would be apparent to those of ordinary skill in the art.




In preferred embodiments, thickness


770


of each of vanes


760


, as measured in a direction essentially parallel to longitudinal axis


320


of main body portion


212


, is less than the characteristic orifice dimension of slit nozzle


216


. In one illustrative embodiment, thickness


770


of vanes


760


is less than about 0.02 inch, and in another illustrative embodiment is less than about 0.01 inch.




It is also preferred that the height


772


of each vane


760


, as measured along a direction that is essentially perpendicular to longitudinal axis


320


of main body portion


212


, exceeds the distance


762


between each of vane


760


by a factor of at least about 2, and, in more preferred embodiments exceeds the distance by a factor of at least about 3, and in the most preferred embodiments exceeds the distance by a factor of at least about 4. While several embodiments of air redirecting elements for redirecting air flowing within a air lance have been illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and structures for providing air redirecting elements to perform the functions described herein, and each of such variations or modifications is deemed to be within the scope of the present invention.




More generally, those skilled in the art would readily appreciate that all parameters and configurations described herein are meant to be exemplary and that actual parameters and configurations will depend upon the specific application for which the systems and methods of the present invention are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, the invention may be practiced otherwise than as specifically described. The present invention is directed to each individual feature, system, or method described herein In addition, any combination of two or more such features, systems, or methods, provided that such features, systems, or methods are not mutually inconsistent, is included within the scope of the present invention.



Claims
  • 1. An air lance for directing a gas through a stencil and onto a surface of an embossable fabric for embossing the fabric comprising:a conduit having at least one inlet opening therein; and at least one orifice forming at least one nozzle, the nozzle being constructed and positioned to direct a stream of the gas through at least one opening in the stencil and onto the embossable surface of a fabric, when the air lance is in operation; and at least one air redirecting element constructed and positioned with respect to the nozzle so that the fractional amount of the stream of the gas directed through the opening in the stencil essentially perpendicular to the embossable surface of the fabric, when the air lance is in operation, is increased with respect to a fractional amount of a stream of the gas directed through the opening in the stencil essentially perpendicular to the embossable surface of the fabric by an essentially equivalent air lance, except not including the air redirecting element.
  • 2. The air lance of claim 1, wherein the gas comprises air.
  • 3. A system for embossing a surface of an embossable fabric comprising the air lance of claim 2.
  • 4. The system of claim 3, further comprising:a stencil, which has a first surface and a second fabric-facing surface that is positionable adjacent and in spaced proximity to an embossable surface of the fabric during air embossing; wherein the conduit forms a main body portion of the air lance; wherein the air lance is secured within the system to maintain the nozzle in a fixed, predetermined position relative to the first surface of the stencil during operation; and wherein the air lance is positioned within the system such that the nozzle is positioned with respect to the stencil so that at least a portion of the nozzle that is closest to the stencil is separated from the first surface of the stencil by a first distance, when the system is in operation, and so that the smallest distance separating the main body portion of the air lance from the first surface of the stencil exceeds the first distance.
  • 5. The system of claim 4, wherein the first distance does not exceed about 0.5 inch, when the system is in operation.
  • 6. The system of claim 5, wherein the first distance does not exceed about 0.25 inch, when the system is in operation.
  • 7. The system of claim 6, wherein the first distance does not exceed about 0.1 inch, when the system is in operation.
  • 8. The system of claim 7, wherein the first distance does not exceed about 0.05 inch, when the system is in operation.
  • 9. The system of claim 8, wherein the first distance does not exceed about 0.025 inch, when the system is in operation.
  • 10. The system of claim 9, wherein the first distance does not exceed about 0.0125 inch, when the system is in operation.
  • 11. The system of claim 10, wherein the first distance is about 0.01 inch, when the system is in operation.
  • 12. The system of claim 4, wherein the system further comprises adjustable air lance positioning means for enabling an operator of the system to adjust the first distance.
  • 13. The system of claim 4, wherein at least a portion of the second fabric-facing surface of the stencil is positioned from the embossable surface of the fabric at a distance not exceeding about 0.02 inch.
  • 14. The system of claim 13, wherein at least a portion of the second fabric-facing surface of the stencil is positioned from the embossable surface of the fabric at a distance not exceeding about 0.01 inch.
  • 15. The system of claim 14, wherein at least a portion of the second fabric-facing surface of the stencil is positioned from the embossable surface of the fabric at a distance not exceeding about 0.005 inch.
  • 16. The system of claim 15, wherein at least a portion of the second fabric-facing surface of the stencil is positioned from the embossable surface of the fabric at a distance of about 0.001 inch.
  • 17. The system of claim 4, further comprising a support surface constructed and positioned to support the underside of the fabric during air embossing of the embossable surface of the fabric with the system.
  • 18. The system of claim 17, wherein the support surface comprises a cylindrical roller.
  • 19. The system of claim 4, wherein the stencil comprises a hollow rotatable cylinder with the air lance being at least partially disposed within the cylinder.
  • 20. The system of claim 4, further comprisinga first drive system constructed and arranged to rotate the stencil at at least a first speed; and a second drive system constructed and arranged to transport the fabric with respect to the position of the air lance at at least a second speed different from the first speed.
  • 21. The system of claim 3, wherein the at least one nozzle has a characteristic orifice dimension less than about 0.2 inch.
  • 22. The system of claim 21, wherein the at least one nozzle has a characteristic orifice dimension not exceeding a maximum characteristic nozzle length of the at least one nozzle.
  • 23. The system of claim 4, wherein the inlet opening of the conduit is positioned in at least one end thereof and wherein the conduit further comprises at least one outlet opening in a side wall of the main body portion of the air lance comprising the at least one orifice forming the at least one nozzle.
  • 24. The system of claim 4, wherein the inlet opening of the conduit is positioned in at least one end thereof and wherein the conduit further comprises at least one outlet opening in a side wall of the main body portion of the air lance,wherein the air lance includes a nozzle-forming component, which nozzle-forming component includes the at least one orifice therein forming the at least one nozzle, wherein the nozzle in the nozzle-forming component is in fluid communication with the outlet opening in the main body portion of the air lance and is constructed and positioned to direct a stream of air through the stencil and onto the embossable surface of the fabric, when the air lance is in operation, and wherein the nozzle forming component is shaped and positioned so that the nozzle in the nozzle-forming component is separated from the first surface of the stencil by a distance that is substantially less than a distance separating the first surface of the stencil and the outlet opening in the main body portion of the air lance, when the air lance is in operation.
  • 25. The system of claim 21, wherein the at least one orifice forming the at least one nozzle is in the shape of an elongated slit.
  • 26. The system of claim 24, wherein the at least one air redirecting element is positioned within the nozzle forming component and upstream of the at least one nozzle.
  • 27. The system of claim 24, wherein the at least one outlet opening in the side wall of the main body portion of the air lance comprises an elongated slot.
  • 28. The system of claim 27, wherein the at least one orifice in the nozzle-forming component comprises an elongated slit that is essentially parallel to the elongated slot in the main body portion of the air lance.
  • 29. The system of claim 28, wherein the width of slot in the main body portion of the air lance exceeds the width of the slit in the nozzle-forming component.
  • 30. The system of claim 28, wherein the nozzle forming component is elongated and is disposed over the slot in the main body portion of the air lance so that the slit in the nozzle forming component and the slot in the main body portion are essentially coextensive.
  • 31. The system of claim 30, wherein the length of a nozzle region of the nozzle-forming component as measured along a direction parallel to the longitudinal axis of the main body portion of the air lance is at least as great as the width of the fabric being embossed by the air lance, when the system is in operation.
  • 32. The system of claim 29, wherein the nozzle-forming component includes a hollow chamber upstream from and essentially coextensive with the elongated slit.
  • 33. The system of claim 32, wherein the chamber contains at the least one air redirecting element therein.
  • 34. The system of claim 33, wherein the at least one air redirecting element comprises a plurality of baffling vanes disposed along essentially the entire length of the chamber, affixed to the chamber to prevent motion of the vanes, and spaced along the length of the chamber at essentially regularly spaced intervals.
  • 35. The system of claim 34, wherein the vanes are oriented so that an air deflecting surface of each vane is essentially perpendicular to the longitudinal axis of the main body portion of the air lance.
  • 36. The system of claim 35, wherein the thickness of each of the vanes, as measured in a direction essentially parallel to the longitudinal axis of the main body portion of the air lance, is less than the characteristic orifice dimension of the slit in the nozzle-forming component.
  • 37. The system of claim 36, wherein the thickness of each of the vanes, as measured in a direction essentially parallel to the longitudinal axis of the main body portion of the air lance, is less than about 0.002 inch.
  • 38. The system of claim 37, wherein the thickness of each of the vanes, as measured in a direction essentially parallel to the longitudinal axis of the main body portion of the air lance, is less than about 0.001 inch.
  • 39. The system of claim 34, wherein the height of each of the vanes as measured along a direction that is essentially perpendicular to the longitudinal axis of the main body portion of the air lance exceeds a distance between each vane by a factor of at least about 2.
  • 40. The system of claim 39, wherein the height of each of the vanes as measured along a direction that is essentially perpendicular to the longitudinal axis of the main body portion of the air lance exceeds a distance between each vane by a factor of at least about 3.
  • 41. The system of claim 40, wherein the height of each of the vanes as measured along a direction that is essentially perpendicular to the longitudinal axis of the main body portion of the air lance exceeds a distance between each vane by a factor of at least about 4.
  • 42. The system of claim 33, wherein the at least one air redirecting element comprises a monolithic baffling structure having a plurality of channels therein, the monolithic baffling structure being oriented within the chamber so that the channels are oriented with their longitudinal axes essentially perpendicular to the longitudinal axis of the main body portion of the air lance.
  • 43. The system of claim 42, wherein the monolithic baffling structure comprises an insert including a plurality of honeycombed cells comprising the channels.
  • 44. The system of claim 43, wherein the thickness of walls of the structure separating each of the channels is less than the characteristic orifice dimension of the slit in the nozzle-forming component.
  • 45. The system of claim 44, wherein the thickness of walls of the structure separating each of the channels is less than 0.002 inch.
  • 46. The system of claim 45, wherein the thickness of walls of the structure separating each of the channels is less than 0.001 inch.
  • 47. The system of claim 42, wherein the height of each of the channels as measured along a direction that is essentially perpendicular to the longitudinal axis of the main body portion of the air lance exceeds a characteristic dimension of each of the channels by a factor of at least about 2, the characteristic dimension of each of the channels being defined as the largest cross-sectional dimension of each of the channels as measured along a direction essentially parallel to the longitudinal axis of the main body portion of the air lance.
  • 48. The system of claim 47, wherein the height of each of the channels as measured along a direction that is essentially perpendicular to the longitudinal axis of the main body portion of the air lance exceeds a characteristic dimension of each of the channels by a factor of at least about 3, the characteristic dimension of each of the channels being defined as the largest cross-sectional dimension of each of the channels as measured along a direction essentially parallel to the longitudinal axis of the main body portion of the air lance.
  • 49. The system of claim 48, wherein the height of each of the channels as measured along a direction that is essentially perpendicular to the longitudinal axis of the main body portion of the air lance a characteristic dimension of each of the channels by a factor of at least about 4, the characteristic dimension of each of the channels being defined as the largest cross-sectional dimension of each of the channels as measured along a direction essentially parallel to the longitudinal axis of the main body portion of the air lance.
  • 50. The system of claim 4, wherein the first distance does not exceed about 0.75 inch, when the system is in operation.
  • 51. An air lance for directing a gas through a stencil and onto a surface of an embossable fabric for embossing the fabric comprising:a conduit having at least one inlet opening therein; and at least one orifice forming at least one nozzle, the nozzle being constructed and positioned to direct a stream of the gas through the stencil and onto the embossable surface of the fabric, when the air lance is in operation, with the nozzle having a characteristic orifice dimension not exceeding 0.05 inch.
  • 52. The air lance of claim 51, wherein the gas comprises air.
  • 53. The air lance of claim 52, wherein the at least one nozzle has a characteristic orifice dimension not exceeding about 0.01 inch.
  • 54. The air lance of claim 53, wherein the at least one nozzle has a characteristic orifice dimension not exceeding about 0.005 inch.
  • 55. The air lance of claim 54, wherein the at least one nozzle has a characteristic orifice dimension not exceeding about 0.001 inch.
  • 56. The air lance of claim 52, wherein the at least one nozzle has a characteristic orifice dimension not exceeding a maximum characteristic nozzle length of the nozzle.
  • 57. The air lance of claim 52, wherein the conduit includes a main body portion having the at least one inlet opening in at least one end thereof and at least one outlet opening in a side wall of the main body portion,wherein the air lance includes a nozzle-forming component, which nozzle-forming component includes the at least one orifice therein forming the at least one nozzle, wherein the nozzle in the nozzle-forming component is in fluid communication with the outlet opening in the main body portion of the conduit and is constructed and positioned to direct a stream of air through the stencil and onto the embossable surface of the fabric, when the air lance is in operation, and wherein the nozzle forming component is shaped and positioned so that the nozzle in the nozzle-forming component is separated from a first surface of the stencil by a distance that is substantially less than a distance separating the first surface of the stencil and the outlet opening in the main body portion of the conduit, when the air lance is in operation.
  • 58. The air lance of claim 52, wherein the at least one nozzle comprises an orifice in the shape of an elongated slit.
  • 59. The air lance of claim 52, wherein the air lance includes at least one air redirecting element constructed and positioned with respect to the at least one nozzle so that the fractional amount of the stream of air directed through the stencil essentially perpendicular to the embossable surface of the fabric, when the air lance is in operation, is increased with respect to a fractional amount of a stream of air directed through the stencil essentially perpendicular to the embossable surface of the fabric by an essentially equivalent air lance, except not including the air redirecting element.
  • 60. An air lance for directing a gas through a stencil and onto a surface of an embossable fabric for embossing the fabric comprising:a conduit having at least one inlet opening therein; and at least one orifice forming at least one nozzle, the nozzle being constructed and positioned to direct a stream of the gas through the stencil and onto the embossable surface of the fabric, when the air lance is in operation, with the nozzle having a characteristic nozzle length exceeding a maximum characteristic orifice dimension of the nozzle by a factor of at least about 3.
  • 61. The air lance of claim 60, wherein the gas comprises air.
  • 62. The air lance of claim 61, wherein the maximum characteristic nozzle length of the nozzle exceeds the characteristic orifice dimension by a factor of at least about 4.
  • 63. The air lance of claim 61, wherein the conduit includes an elongated main body portion and wherein the at least one orifice forming the at least one nozzle comprises at least one outlet opening in a side wall of the main body portion of the conduit.
  • 64. The air lance of claim 63, wherein the elongated main body portion of the conduit includes a plurality of orifices comprising a plurality of nozzles.
  • 65. The air lance of claim 64, wherein the plurality of orifices are essentially circular in shape.
  • 66. The air lance of claim 63, wherein the elongated main body portion of the conduit includes an elongated slit comprising a slit-shaped nozzle.
  • 67. The air lance of claim 66, wherein the elongated slit has a width that is essentially constant along its length.
  • 68. The air lance of claim 66, wherein the conduit is tubular in shape having a first and a second end and having one inlet opening in the first end thereof with the second end thereof sealed, and wherein the width of the elongated slit varies along a length of the main body portion such that the width is greatest in a region of the slit closest to the first end of the conduit and smallest in a region of the slit closest to the sealed second end of the conduit.
  • 69. The air lance of claim 63, wherein the characteristic nozzle length of the at least one nozzle is essentially equal to the wall thickness of the main body portion in which the at least one outlet opening is formed.
  • 70. The air lance of claim 69, wherein the wall thickness does not exceed about ⅛ inch.
  • 71. The air lance of claim 63, wherein the air lance includes at least one air redirecting element constructed and positioned with respect to the at least one nozzle so that the fractional amount of the stream of air directed through the stencil essentially perpendicular to the embossable surface of the fabric, when the air lance is in operation, is increased with respect to a fractional amount of a stream of air directed through the stencil essentially perpendicular to the embossable surface of the fabric by an essentially equivalent air lance, except not including the air redirecting element.
  • 72. The air lance of claim 71, wherein the at least one air redirecting element is positioned inside the main body portion of the conduit.
  • 73. The air lance of claim 72, wherein a substantial fraction of the characteristic nozzle length of the at least one nozzle comprises a length of the at least one air redirecting element as measured in a direction essentially perpendicular to a longitudinal axis of the main body portion of the conduit.
  • 74. The air lance of claim 61, wherein the conduit includes a main body portion having the at least one inlet opening in at least one end thereof and at least one outlet opening in a side wall of the main body portion,wherein the air lance includes a nozzle-forming component, which nozzle-forming component includes the at least one orifice therein forming the at least one nozzle, wherein the nozzle in the nozzle-forming component is in fluid communication with the outlet opening in the main body portion of the conduit and is constructed and positioned to direct a stream of air through the stencil and onto the embossable surface of the fabric, when the air lance is in operation, and wherein the nozzle forming component is shaped and positioned so that the nozzle in the nozzle-forming component is separated from a first surface of the stencil by a distance that is substantially less than a distance separating the first surface of the stencil and the outlet opening in the main body portion of the conduit, when the air lance is in operation.
  • 75. An air lance for directing a gas through a stencil and onto a surface of an embossable fabric for embossing the fabric comprising:an elongated tubular conduit having at least one inlet opening therein and at least one internal support strut attached therein, which support strut is constructed and positioned within the conduit to resist expansion of the conduit when the air lance is in operation; and at least one orifice in the shape of an elongated slit forming at least one nozzle, the nozzle being constructed and positioned to direct a stream of the gas through at least one opening in the stencil and onto the embossable surface of the fabric, when the air lance is in operation.
  • 76. The air lance of claim 75, wherein the gas comprises air.
  • 77. A method for embossing a surface of an embossable fabric with a gas comprising:supplying a flow of the gas to an air lance; flowing a stream of the gas through at least one nozzle of the air lance so that essentially the entire stream of the gas is directed towards a surface of a stencil facing and adjacent the nozzle at an angle of at least about 63 degrees with respect to a longitudinal axis of the air lance; passing the stream of the gas through at least one opening in the stencil; and impinging the stream of the gas onto the embossable surface of the fabric, thereby embossing the embossable surface of the fabric.
  • 78. The method of claim 77, wherein the gas comprises air.
  • 79. The method of claim 78, wherein during the flowing step the at least one nozzle is positioned so that at least a portion thereof is separated from the surface of the stencil facing and adjacent the nozzle by a distance not exceeding about 0.75 inch, such that the stream of air includes at least a portion thereof with a length between the nozzle and the surface of the stencil not exceeding 0.75 inch.
  • 80. The method of claim 79, wherein during the flowing step the at least one nozzle is positioned so that at least a portion thereof is separated from the surface of the stencil facing and adjacent the nozzle by a distance not exceeding about 0.0125 inch, such that the stream of air includes at least a portion thereof with a length between the nozzle and the surface of the stencil not exceeding 0.0125 inch.
  • 81. The method of claim 80, wherein during the flowing step the velocity of air exiting the at least one nozzle is at least about 12,000 feet per minute.
  • 82. The method of claim 81, wherein during the flowing step the at least one nozzle through which the stream of air flows has a characteristic orifice dimension not exceeding 0.2 inch.
  • 83. The method of claim 82, wherein during the impinging step at least a portion of a fabric-facing surface of the stencil is positioned from the embossable surface of the fabric at a distance not exceeding about 0.02 inch.
  • 84. The method of claim 83, wherein during the flowing step the stream of air flows through a nozzle-forming component removably connected to a main body portion of the air lance, whereinthe nozzle-forming component includes at least one orifice therein forming the at least one nozzle, wherein the nozzle is in fluid communication with at least one outlet opening in the main body portion, and wherein the nozzle forming component is shaped and positioned so that the nozzle in the nozzle-forming component is separated from the surface of the stencil facing and adjacent the nozzle by a distance that is substantially less than a distance separating the surface of the stencil facing and adjacent the nozzle and the outlet opening in the main body portion of the air lance.
  • 85. The method of claim 84, wherein the at least one orifice forming the at lest one nozzle in the nozzle-forming component comprises an elongated slit.
  • 86. The method of claim 85, wherein the nozzle forming component includes at least one air redirecting element therein and wherein prior to the flowing step at least a portion of the flow of air supplied to the air lance impinges upon and is redirected by the air redirecting element.
  • 87. The method of claim 86, wherein during the flowing step the velocity of the air stream flowing through the at least one nozzle is essentially constant along essentially the entire length a region of the air lance along which the nozzle is positioned.
  • 88. A system for embossing a surface of an embossable fabric with a gas comprising:an elongated conduit extending across and substantially parallel to the embossable fabric; means for redirecting gas flow flowing along the length of the conduit so that essentially all of the gas flow exits from at least one outlet opening in the conduit towards the fabric in a direction making an angle of at least about 45 degrees with respect to the longitudinal axis of the elongated conduit, with said means comprising a series of baffles shaped and positioned to intercept and deflect the gas flow.
  • 89. The system of claim 88, wherein the gas comprises air and the gas flow comprises an air flow.
  • 90. A method for embossing a surface of an embossable fabric with a gas comprising:directing a stream of the gas through a stencil and onto the embossable surface of the fabric with an air lance including a conduit, having at least one inlet opening therein, and at least one orifice forming at least one nozzle having a characteristic orifice dimension not exceeding 0.05 inch.
  • 91. The method of claim 90, wherein the gas comprises air.
  • 92. A method for embossing a surface of an embossable fabric with a gas comprising:directing a stream of the gas through a stencil and onto the embossable surface of the fabric with an air lance including a conduit, having at least one inlet opening therein, and at least one orifice forming at least one nozzle having a characteristic nozzle length exceeding a maximum characteristic orifice dimension of the nozzle by a factor of at least about 3.
  • 93. The method of claim 92, wherein the gas comprises air.
  • 94. A method for embossing a surface of an embossable fabric with a gas comprising:directing a stream of the gas through a stencil and onto the embossable surface of the fabric with an air lance including an elongated tubular conduit, having at least one inlet opening therein, at least one internal support strut attached therein, which support strut is constructed and positioned within the conduit to resist expansion of the conduit when the air lance is in operation, and at least one orifice in the shape of an elongated slit forming at least one nozzle.
  • 95. The method of claim 94, wherein the gas comprises air.
  • 96. A method for embossing a surface of an embossable fabric with a gas comprising:directing a stream of the gas through a stencil and onto the embossable surface of the fabric with an air lance including a conduit, having at least one inlet opening therein, at least one orifice forming at least one nozzle, and at least one air redirecting element constructed and positioned with respect to the nozzle so that the fractional amount of the stream of the gas directed through the stencil essentially perpendicular to the embossable surface of the fabric is increased with respect to a fractional amount of a stream of the gas directed through the stencil essentially perpendicular to the embossable surface of the fabric by an essentially equivalent air lance, except not including the air redirecting element.
  • 97. The method of claim 96, wherein the gas comprises air.
RELATED APPLICATIONS

This application is a national stage filing under 35 U.S.C. §371 of PCT International Application No. PCT/US00/13993 filed May 22, 2000, which was published under PCT Article 21(2) in English. PCT International Application No. PCT/US00/13993 claims the benefit under 35 U.S.C. §119(e) of U.S. provisional patent application serial No. 60/135,379 filed May 21, 1999.

PCT Information
Filing Document Filing Date Country Kind
PCT/US00/13993 WO 00
Publishing Document Publishing Date Country Kind
WO00/71802 11/30/2000 WO A
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Provisional Applications (1)
Number Date Country
60/135379 May 1999 US