Patent Application
20070084390
The present invention relates generally to seams for garments and their manufacture. More particularly, the seams of the present provide greater comfort to the wearer and are less bulky than conventional seams, which are formed from multiple plys (e.g., layers) of material. The seams of the present invention find particular advantage in foundation garments (i.e. garments worn under other garments) especially those over which shear or clingy outer garments are worn and through which bulky seams are clearly (and undesirably) visible.
In a typical garment, a sewn seam is formed between two fabric panels. Seams are sewn or otherwise formed in a variety of different ways, depending upon the material, the feature of the garment formed by the seam and numerous other factors. In a typical sewn seam, the panels of fabric to be joined by the seams are superposed at their edges and stitched through at a short distance from the edges to form two overlapping facing strips at the edge of the seam. The facing strips are then “plowed” or folded on their respective panels, and each is stitched flat against the panel. This seam is formed on the inside of the garment so that the stitched facing strips are not visible on the outside. In many garments where the thick seam can lead to chafing or other discomfort, the plowed strips are then covered with a tape which is sewn to the panel through the plowed strips. Typically, the edges of the tape are folded under in order to avoid fraying, before the tape is sewn to the panels. However, the seam is several plies thick (even without the tape) and defines a noticeable ridge in the fabric. This ridge is generally visible and even accentuated when in foundation garments over which other garments (e.g., shear or close fitting outer garments) are worn. Also, in foundation garments that provide shaping and/or support the ridge can cause discomfort, chafing etc., especially where support and/or shaping are provided.
However, sewn seams, despite these disadvantages, are advantageous and desirable in many classes of garments that provide support or shape to the wearer. Sewn seams enable the manufacturer to tailor the garment to provide support or shape in a particular area (i.e. the area of the seam). Also, the sewn seam enables the manufacturer to join two types of materials together, or to configure the fabric panels joined together by the seam to provide particular support or shape to the wearer.
One class of garments where the sewn seam finds particular advantage is brassieres (more commonly referred to as bras). The bra is a complicated garment from a manufacturing perspective because it is a garment with cups that define a vaulted three dimensional shape. Often, these cups are formed from flat panels that are sewn together. The cup portion is formed with a sewn, curved seam in the front between two panels. The seam provides an advantageous element of support for the wearer at this location. This support is especially advantageous for ample breasted women. Sewn seams are also advantageous because they allow two different types of material to be joined together by the seam. Thus, the manufacturer can join together two materials, each with distinct characteristics and functions in the garment. For example, again in the context of a bra cup, a sturdier material that provides support can be joined with a stretchier material that provides comfort. The sewn seam provides advantages in other support garments as well. Sewn seams can be placed in foundation garments at the precise location where support or particular shape is desired. Thus, from a support/shape perspective, the sewn seam is very advantageous when used in foundation garments and active wear.
However, the sewn seam has fallen from favor from use in foundation garments and shape wear for purely aesthetic reasons. Specifically, the visibly detectable seam ridge is extremely undesirable from a fashion point of view. Consequently, seamless constructions have been sought for foundation garments and active wear. While these solutions do address the problem of a highly visible seam, they are deficient from a support/shaping perspective. For example, bras have been made with seamless cup portions comprising a single piece of fabric. This single panel construction offers virtually no support and cannot be used by a large segment of the female population (typically those women who require a large cup bra also require a bra that provides at least some degree of support).
Bras with molded cups have been offered as an alternative to bras with cups having seams. However, manufacture of the molded cup is labor intensive, since it requires molding the cup to a particular configuration. This requires the use of many different molds to approximate the breast size of the wearer. Also, the process of molding the fabric (typically a heat treatment that removes the stretch from an elastic material such as spandex) is time consuming. The molded cup also makes very inefficient use of fabric, since rather large areas of fabric for the cup and the strap/stay portion of garment must be reserved for clamping the cups to the strap/stay portion. These clamped portions are subsequently removed and discarded, which wastes fabric.
Consequently, fashionable and manufacturable alternatives to conventional multi-ply seams that will provide adequate support and shape for foundations and active wear continue to be sought.
The present invention is applicable to seams for many types of garments. However, it is particularly advantageous in the manufacture of foundation garments, active wear, shape wear and the like type of garments (i.e. garments that are configured for fit, support and/or control). The seams of the present invention present a smooth surface, compared to prior art multi-ply seams. The smooth seams are not visually detectable when in a foundation garment over which close fitting or shear garments are worn. However, unlike prior art alternatives to multi-ply seams, the seams of the present invention permit the manufacturer to tailor the garment to provide support, comfort or shape in addition to providing the highly desirable smooth appearance. In the context of bras, the present invention provides particular advantage over the molded bra cup solution, since the present invention allows for tailoring the bra cup for fit, comfort and support whereas a molded bra cup cannot be so tailored. Also, again compared with multi-ply seams, the seams of the present invention are less likely to irritate or chafe skin in contact with the seam.
In accordance with one embodiment of the present invention, seams are formed of two fabric panels (i.e. a first panel and a second panel), each panel having a first edge. The first edge of the first panel abuts, but does not substantially overlap, the first edge of the second panel. The first and second panels are joined together by an adhesive. In preferred embodiments, the edges are connected by a material strip carrying the adhesive. The adhesive is applied to the material strip in an uncured state. Preferably, the material strip is placed in contact with the fabric panels to form the seam while the adhesive is still substantially uncured. In another preferred embodiment of the present invention, a seam is formed by applying a first material strip carrying adhesive on a first major surface at the interface of the two abutting fabric panels, followed by cure, and then applying a second material strip carrying adhesive on a second, opposing major surface at the interface of the two fabric panels (again followed by cure).
Although any conventional fabric is contemplated as suitable for the fabric panels, it is advantageous if the fabric panels are synthetic materials. Examples of suitable fabrics include synthetic materials such as polyester, rayon, polyurethane foam, spandex (e.g., Lycra® a registered trademark of Invista Technologies S.A.R.L.), nylon and the like materials and natural fiber materials such as cotton and wool. As one skilled in the art is aware, fabric materials typically carry a finish material which gives a material a particular sheen and/or feel. One skilled in the art is aware that there are a vast number of finish compositions for fabrics. In the present invention, a fabric finish is selected that will not substantially degrade the adhesion between the adhesive and the fabric panels. One skilled in the art will be able to select an appropriate finish based upon the particular adhesive used. For example, if a water-based (i.e. hydrophilic) adhesive is used, hydrophobic (e.g., non polar) finishes should be avoided. Silicone-based finishes are examples of those finishes that should be avoided when a water-based adhesive is used. With certain adhesives, it may be advantageous to use unfinished fabrics if possible from an appearance/texture perspective.
Suitable adhesives are those that wet both the fabric and the material strip used to join the fabric panels (it is advantageous, but not required, that the fabric and material strip be the same material). The adhesive is applied onto the material strip and placed into contact with the fabric in an uncured state, and subsequently cured when in contact with the material strip and fabric panels. It is also advantageous, but not required, for the adhesive to stretch in its cured state. It is advantageous if the adhesive will elongate at least one hundred percent (i.e. can stretch to twice its length in its relaxed state). It is contemplated that the fabric panels will stretch more than the adhesive in at least some embodiments.
Many different adhesives are contemplated as suitable for forming the seam of the present invention. In one embodiment of the present invention, thermosetting adhesives are used. As used herein, thermosetting adhesives are adhesives that cure when subjected to a thermal cycle of heating followed by cooling. Another characteristic of thermosetting adhesives is that, once cured, they cannot be remelted when heated.
In another embodiment of the present invention, thermoplastic adhesives are used. Thermoplastic adhesives, much like thermosetting adhesives, cure when subjected to a thermal cycle of heating and cooling. However, unlike thermosetting adhesives, thermoplastic adhesives can be remelted after cure.
Other adhesives that cure using mechanisms other than a thermal cure (e.g., ultraviolet radiation cure) are also contemplated as suitable for use in the present invention. Again, the requirements are suitable adhesion to fabric and maintaining adhesion and flexibility over time when subjected to repeated wear and washing.
In some applications where the fabric panels are relatively thick (e.g., 5 mils or thicker and, more typically about 20 mils or more), such as when the fabric is a fiberfill or urethane material, adhesive may be applied directly to the abutted edges. A strip of material is also used to carry additional adhesive to form the completed seam in these embodiments. Forming a seam from relatively thick materials in this manner ensures that gaps in the finished seam will not form.
In certain preferred embodiments, the seam is formed by applying to the material strip a heated, thermosetting adhesive in fluid form. One example of such an adhesive is a polyurethane adhesive (PUR adhesive) manufactured by the National Starch Co. It is advantageous if the adhesive contains additives that allow the seam to stretch along with the fabric panels joined by the seam. A seam manufactured in accordance with the present invention is virtually undetectable through clothing, and, when a strip of material is used, as in a brassiere cup, it provides an element of support which is adequate for most of the female population.
Although the adhesive, when introduced into contact with the material strip, wets the surface of the strip, the amount of adhesive, the thickness of the adhesive and its viscosity are selected to ensure that the adhesive does not permeate through the entire thickness of the material strip. The reason for this is twofold. If the seam is in contact with the wearer, it is preferred that the wearer not be in contact with the adhesive used to form the seam. If the seam is on the exterior of the garment, it is not desirable for the adhesive to be visible on the surface of the material strip. The adhesive, if visible through the seam, might give the garment a stained, soiled or otherwise undesirable appearance.
An apparatus for forming an adhesive seam is also contemplated. The apparatus has a conveyor that grips and draws two fabric panels into abutting contact. In one embodiment the conveyor is a dual belt feeder that cooperates with a knurled roller to draw fabric panels into the nip between the belts and the roller. Both the belt feeder and roller are provided with driver assemblies that impart the desired circular motion to the belts and cause the belt and rollers to draw the fabric panels into the nip thereof. The apparatus is also equipped with a feeding mechanism that feeds the strip of material from a roll or other mechanism that is suitable to support and dispense such material. As the strip of material is fed from the dispensing mechanism, adhesive is applied to the strip of material. The adhesive is applied using mechanisms such as a spray nozzle, a slot nozzle or a roller coater. The adhesive is applied to the material in a substantially uncured form.
In another embodiment, at least one of the rollers forming the nip into which the fabric is fed and drawn is knurled. At least one of the rollers is driven and it is advantageous if both rollers are both driven and knurled. It is advantageous if the rollers have the same size and move at the same speed, as such an arrangement provides an even seam.
The roller surfaces can be either flat, concave or convex. It is advantageous if at least one of the roller surfaces is convex, as this surface configuration draws the fabric into and through the nip efficiently.
The apparatus feeds the strip of material carrying the adhesive into contact with the fabric panels in abutting contact such that the strip of material is placed in contact with both panels and bridges the region where the two panels are brought together along substantially the entire length of that region. Bringing the strip of material into contact with the fabric panels in this manner, the apparatus forms a seam joining the first panel and the second panel.
In an advantageous embodiment, the strip of material is backed with paper, such that the paper backing is interposed between the strip of material and the roller. Among other advantages, the paper prevents adhesive, placed on the strip of material to promote adhesion between it and the fabric, from coming into contact with the rollers. After the strip of material is placed into contact with the fabric panels and begins to cure, the paper backing is removed from the strip of material.
After the seam is formed, the adhesive is at least partially cured so that the seam will hold the panels together when the assembled panels are removed from the apparatus for subsequent processing. The apparatus has a curing station that facilitates at least partial cure of the adhesive. The curing conditions depend upon the adhesive that is used. For example, thermosetting resins are heated to render them sufficiently viscous for application onto the material strip. Generally, the adhesive is more viscous (i.e. has a greater resistance to flow) at lower temperatures. At lower temperatures, the adhesive is applied onto the strip of material with a greater bead thickness. Generally, a temperature is selected that will ensure a certain minimum degree of tackiness between the panels themselves or between the panels and the strip of material used to join the panels together.
Such adhesives are cured by subjecting them to cool, moist air. Thus, the curing section for an apparatus in which a thermosetting resin is used to assemble the seam will introduce cool, moist air proximate to the assembled seam in order to at least partially cure the adhesive. It is advantageous if the assembled seam is placed on a surface with a contour that somewhat mimics that of the finished seam. Placing the seam on such a surface will prevent the fabric panels from bunching, pulling, etc., which could place the partially cured seam under undue stress. Such stress could cause undesired imperfections in the fully cured seam (e.g., gaps, irregular appearance, etc.). Curing on an appropriately contoured surface ensures that the seam will not be subjected to undue mechanical stress during cure. Appropriate curing conditions depend upon a number of different factors among them being: 1) the temperature of the adhesive when applied to the seam; 2) the thickness of the bead of adhesive that is deposited to form the seam; 3) the amount of moisture in the air; 4) the temperature of the air; and 5) the volume of air circulating past the seam as it is cured.
The foregoing brief description, as well as further objects, features, and advantages of the present invention will be understood more completely from the following detailed description of presently preferred, but nonetheless illustrative embodiments in accordance with the present invention, with reference being had to the accompanying drawings in which:
FIGS. 9A-B illustrate the top belt assembly illustrated in
Referring to the drawings,
The fabric panels 10, 12 are typically finished fabrics, although the fabric panels can also be unfinished. Finished fabrics are well known to those skilled in the art. There are many fabric finishes, each providing a certain feel and appearance to a fabric. If finished, the fabric finish must be compatible with the adhesive that is used to form the seam. In the context of the present invention, compatible means that the adhesive will adhere to the fabric with the finish thereon. One skilled in the art can readily ascertain how to select a finish that is suitable for use with a particular adhesive, and vice-versa. For example, if a water-based (i.e. hydrophilic/polar) adhesive is used, then the finish should not be hydrophobic or non-polar. Silicone-based finishes are examples of finishes that are not suitable for forming an adhesive seam using a water-based adhesive. If a fabric has a finish to which the adhesive will not suitably adhere, the problem may be addressed by spray washing the fabric to remove or modify the finish. Finish properties can also be modified (e.g., the finish texture can be roughened) by subjecting the fabric to an electric field. One skilled in the art is well versed in the materials and conditions required to remove/modify a fabric finish, and, as such, they will not be discussed in detail herein.
The fabric panels 10, 12 are illustrated as rectangular, but can be cut to any desired shape or size. One skilled in the art is aware of the many different techniques used to cut fabric panels for use in garment manufacture. Such techniques include Gerber cutting, die cutting and laser cutting. It is advantageous if the fabric panels are cut using the more precise techniques of laser cutting, sonic cutting or die cutting. Laser cutting, sonic cutting, hydro cutting and die cutting provide fabric panels with smoother, more uniform edges compared with other conventional techniques for cutting fabric (e.g., Gerber cutting). It is easier to abut fabric panels with smooth, uniform edges, and panels with such edges are less likely to bunch or otherwise deform in a manner that might result in a non-uniform seam. In this regard, seam imperfections (e.g., dents or holes at the seam edge) may not adversely affect the mechanical integrity of the seam. However, such imperfections may not be acceptable from an appearance perspective. In a preferred embodiment of the present invention, the fabric panels are cut from the fabric using laser cutting, hydro cutting or sonic cutting. Although applicants do not wish to be held to a particular theory, it is applicants' belief that laser cutting and sonic cutting are more accurate and therefore provide for a more consistent and uniform cut. This ensures greater conformity of the edges of the two fabric panel that are brought together in abutted alignment. Also, applicants also believe that laser cutting and die cutting fuse, at least somewhat, the fibers at the cut edge of the fabric panels. This also allows the fabric panels to be fitted together more precisely, providing for a smoother seam that is less visible under clothing.
The material and thickness of the fabric panels is largely a matter of design choice. While there is no requirement that the fabric panels be the same material, there are certain constraints when different materials are used. One constraint is the finish on the materials. While there is no requirement that the materials have the same finish, the finishes should permit a comparable degree of adhesion between the panel and the adhesive. In this regard, one panel should not have a hydrophilic finish when the other has a hydrophobic finish, for example. Another constraint is thickness. While there is no requirement that the fabric panels be of identical thickness, it is advantageous if they are of similar thicknesses. A substantial difference in thickness between the two panels (e.g., one panel is more than fifty percent thicker than the other panel) will result in an uneven seam that is more likely to be visible through shear or clingy garments worn over any such seam compared to a seam formed from two panels of substantially equal thickness.
In
The piece of material used to join together the two fabric panels is referred to herein as a strip. While the term strip typically connotes a long and narrow configuration, the term strip, as used herein, is meant to include a piece of material of any suitable configuration. The strip of material is also of any suitable thickness. While any thickness is contemplated, it is advantageous if the thickness of the material strip is less than the thickness of the fabric panels. Thicker strips, while contemplated, are contrary to the objectives of the present invention, which is to provide a less noticeable seam. In preferred embodiments, the strip of material is thicker than the adhesive applied thereon. This ensures that the adhesive will not wet through the strip of material. Examples of suitable thicknesses for the material strip are in the range of about 1 mil (a mil is 1/1000 of an inch) to about 7 mils thick.
The weave of the strip is selected to prevent adhesive from penetrating through the thickness of the strip. As previously noted, this prevents the adhesive from being visible on the surface of the material strip, resulting in an undesirable appearance. This also prevents adhesive from penetrating through the material strip on the underside of the seam, which would result in adhesive being adjacent the skin of the wearer. This could result in skin irritation or other discomfort to the wearer. Again, the objective is to prevent the adhesive from penetrating through the thickness of the strip. Again, this is a feature that provides a seam with an advantageous appearance and is not required to ensure the mechanical integrity of the seam.
Various materials and material thicknesses may be selected for the elongated strip of material, depending on the application. Typically the material will be the same as or similar to the panel material, although this is not required. If the material is finished, the finish must not inhibit the adherence of the adhesive, as described above. The thickness of the material strip is largely a matter of design choice, and will be governed largely by the desired appearance of the seam. For example, strips having a thickness that will show through outerwear are less desirable. The one requirement is that the strip of material be at least as thick, and preferably thicker, than the adhesive applied to and carried by the strip of material. In one embodiment, the material is a tricot knit fabric material having a thickness of about 1 mil to about 7 mils and a width in the range of about 3/32″ to about ¼″. However, those skilled in the art will appreciate that strips made of many different materials and with many different sizes may be used.
The width of the strip of fabric material is also a matter of design choice. Typically, the strip of fabric material will have a width of about 0.25 inches to about 0.75 inches. However, widths outside this range are contemplated.
As noted above, it is advantageous if the strip of fabric material does not have an open weave that will allow the adhesive to penetrate through the thickness of the strip of material. However, it is advantageous if the strip of material does stretch at least somewhat in both the length and width directions. This provides the seam with a bit of give, which adds some additional adjustability and thus comfort for the wearer. However, although desirable, the degree of stretch in the width direction should never be such that gaps form in the seam due to the degree of stretch provided by the strip of fabric material.
One skilled in the art is aware that degree to which fabrics stretch is almost unlimited. Some fabrics have a weave and material that provides for very little (i.e. almost zero percent) stretch. In the context of the present invention, the percent to which a fabric stretches is the difference in the dimension of the fabric in the direction of the stretching force compared to that dimension when the fabric is in its relaxed state (i.e. no stretching force applied) as a percent of the dimension of the fabric in its relaxed state. As one skilled in the art is aware, fabrics stretch up to two hundred (200) percent or even higher.
Thus, except for the constraints on open weave stated above, the seam of the present invention can be formed using a material strip and fabric panels with any degree of stretch (including zero degrees). Certain considerations might inform the selection of a particular degree of stretch, chief among them being the need to avoid a seam that will stretch to form gaps between the panels. This consideration creates a greater degree of tolerance for stretch in the length direction than in the width direction. Also, since in certain embodiments, the adhesive also stretches up to one hundred percent, one will typically select fabric panels, material strip and adhesives with a commensurate degree of stretch.
As noted above, many different adhesives are contemplated as suitable. The selected adhesive will adequately adhere to the fabric panels forming the seam and the finish on such panels. Furthermore the adhesive, once cured, must remain supple over time even through repeated wearings and washings of the garment. Examples of suitable adhesives include thermosetting adhesives and thermoplastic adhesives. One example of a thermoplastic adhesive is Griltex® copolyester adhesive. Thermoplastic adhesives are contemplated as useful for forming a seam when the fabric panels are knitted or woven fabric. In one embodiment, it is advantageous if the adhesive contains a dye so that is at least somewhat matches the color of the fabric panels and/or the material strip. Dyes or other additives suitable for coloring adhesive are well known in the art and not described in detail herein. The color of the selected dye depends upon, for example, the color of the fabric panels and the material strip and the degree of match between the adhesive and the fabric panel/material strip that is sought. Also, the dye or other color additive must be chemically compatible with the adhesive. For example, if the adhesive is water-based, then the dye would also be water-based. Conversely, if the adhesive is hydrophobic, then the dye would also be hydrophobic.
One example of a thermosetting adhesive is a polyurethane based adhesive such as PUR from National Starch Inc. In order to provide an adhesive with sufficient stretch when cured, additives can be included with the adhesive. One skilled in the art is aware of suitable additives for thermosetting adhesives that increase the stretch in the cured adhesive. In certain preferred embodiments, the adhesive is one that cures when cooled, and the cure is accelerated in a moist air environment.
In the embodiment of the present invention in which a thermosetting adhesive is used, the adhesive is heated in a container under pressure. An inert atmosphere is provided to pressurize the adhesive. In one embodiment, the inert atmosphere is an argon atmosphere. In another embodiment, the inert atmosphere is super-dried air. Nitrogen is yet another example of an inert atmosphere. In the context of dispensing adhesive, an inert atmosphere is one in which the adhesive does not substantially cure. The adhesive is dispensed either by pressure from the inert atmosphere alone or by use of a mechanical pump. The adhesive material is dispensed in liquid form. In the embodiment where pressurized argon is used to dispense the adhesive, approximately five pounds of argon pressure is all that is required to accomplish this objective. The material cures when cooled in ambient air and the cure is accelerated if the air is moist. The greater the amount of moisture in the air, the faster the cure. The preferred adhesive is a thick paste that is heated to be converted to a liquid form. The melting temperature will depend upon the particular adhesive used. Specifically an adhesive with a melting temperature that is less than the temperature that would adversely affect the fabric panels being attached with the seam is preferred. For example, if fabric panels will be adversely affected by temperatures higher than 350° F., adhesives with a melting temperature higher than about 350° F. should be avoided. Similarly, if the fabric can withstand temperatures of about 300° F. or less, then and adhesive with a melting temperature of less than about 300° F. should be used.
Adhesives that require temperatures of greater than 350° F. to be in liquid form are less preferred because the synthetic materials used for the strip of material and fabric panels might be damaged if placed into contact with a substance at such higher temperatures. Also, high temperatures are preferably avoided for operator safety. It is advantageous if the uncured adhesive melts at temperatures in the range of about 220° F. to about 280° F., and more preferably temperatures of about 220° F. to about 260° F. and is sufficiently liquid (i.e. have a viscosity that is sufficiently low) at these temperatures to facilitate application onto the strip of material. In this regard, adhesives with curing temperatures in the lower half of the aforesaid range have a tackiness when the adhesive is applied to the strip that provides for advantageous handling of the seam prior to cure. In any event, overheating is to be avoided as it can cause the adhesive to discolor (e.g., turn yellow). This can cause a less than desirable appearance.
In this regard, it is also advantageous if the fabric itself is heated when the seam is formed. Heated fabric is less prone to wrinkle, and a smooth seam will more likely result with the fabric is heated. Again the upper limit on temperature is the heat tolerance of the fabric itself. There is no need to heat the fabric to a temperature in excess of the melting temperature of the adhesive.
The adhesive is applied using any suitable mechanism. A roller coater provides uniformity and controlled application, but other mechanisms such as a slot nozzle or a spray nozzle are also contemplated as suitable. A slot nozzle provides a bead of adhesive and therefore permits the application of adhesive directly onto the strip at a controlled thickness. A spray nozzle permits a large amount of adhesive to be applied quickly but the amount of “overspray” onto other surfaces is greater with a spray nozzle than with a slot nozzle or roller coater. Those skilled in the art will appreciate that adhesive may be applied by any other conventional method that will allow it to wet the strip of material 14. Application conditions (e.g., adhesive thickness) are controlled to prevent the adhesive from bleeding through the strip of material. For example, if the strip of material is about 7 mils thick, the adhesive is applied using conditions (e.g., thickness, viscosity, etc.) that limit the penetration of the adhesive into the strip of material to about 5 mils or less.
In
As previously noted, it is advantageous if the fabric seam is placed on a surface with a contour that mimics the contour of the fabric article. Such an arrangement avoids mechanical stress on the seam as it cures.
Although the seam depicted in
Adhesive-backed strips have been used in garment manufacture for either garment hems or elastic edges. The adhesive strips used for these purposes are not suited for making seams, especially seams with corners or curves such as the seams found in bra cups. The adhesive-back strips are supplied with the adhesive pre-applied on the strip (i.e. well in advance (e.g., at least hours, more likely days and typically weeks) of using the strip to make the garment) and partially cured. The adhesive is therefore in a solid state and the strips must be reheated when the strip is applied to the seam. Solid adhesive is less preferable to the adhesive applied in liquid form, as described herein. In the present invention, the liquid adhesive is applied to the material strip only moments before the seam is formed. Corner and curved seams are readily formed using the material strip carrying liquid adhesive as described herein.
One advantage of the present invention is that, since the panels 10 and 12 are in abutted alignment for seam formation, the need for a seam allowance is avoided. A sewn seam needs to have a seam allowance (i.e. extra material) where the panel edges are sewn together. Thus a portion of each panel extends beyond the sewn seam. This extended edge portion is plowed open and sewn as discussed above. The extended edge portion serves no purpose in the garment (it is typically in the inside of the garment, hidden from view). In the present invention, there is no need for a seam allowance, since the edges are abutted and the adhesive seam is formed at the abutment of the two edges. The panels do not extend beyond the abutted region. Therefore, the fabric panels can be cut to the exact size that is required for the garment, without the need for a seam allowance. Thus, the present invention provides a significant saving of material by avoiding the need for a seam allowance.
The present invention provides particular advantage in the manufacture of bra cups. In the manufacture of bra cups, a substantial amount of manual labor is required. This is especially true in the case of molded cups that require time and labor to shape into different sizes. In addition, in prior art methods for bra manufacture, the fabric must be cut oversized in order to provide clamping areas, which eventually become waste material. Accordingly, the seams of the present invention will save a substantial amount of material when used to manufacture bras. In addition, those skilled in the art will appreciate that the process for forming the adhesive seams described generally above is capable of being automated. Using an automated process for bra manufacture also provides significant advantages over prior art techniques for making bras which are more highly customized and therefore more labor intensive.
Various modifications to the process described above are contemplated, and those skilled in the art will appreciate that modifications in addition to those describe herein are possible without departing from the scope and spirit of the invention. For example, adhesive might be applied to the fabric panels rather than the strip of material. Alternately, tape (i.e. a strip of material already carrying an adhesive) could be provided, for example, in rolls. The tape is then heated to liquefy the adhesive prior to applying the tape to the seam. In yet another modification, the heat may be applied after the tape is placed into contact with the fabric panels. This allows the seam to be formed in one quick operation. Also, the panels can be lightly stitched together (i.e. basted) either before or after the adhesive seam is formed for additional seam integrity. Since the objective of the present invention is to provide a less visible, more comfortable seam it is preferable that the material strip carrying adhesive be applied over any such stitching.
In yet another embodiment, the strip of material is applied with a paper backing. Once adhesive is applied to the front side of the strip of material, and the strip of material is placed into contact with the fabric panels to form the seam, the paper backing is removed from the strip of material.
Referring to
The apparatus 200 has a top belt assembly 210 and a bottom roller assembly 220. The top belt assembly is configured to feed two fabric panels (not shown) into abutting contact with each other when fed into the nip 201 defined by the top belt assembly 210 and bottom roller assembly 220. Roller 222 is mounted on a slant post 221 which allows the panels of material to naturally curve as they pass through the nip region 201 defined by top belt assembly 210 and roller 220.
An alternate configuration of the assembly 200 illustrated in
Many different types of paper are contemplated as suitable. In one embodiment, standard craft paper (i.e. paper with a thickness of 5/7000″ (7.143×10−4 inches)) is contemplated as suitable. The thickness is selected so that the craft paper can act as an effective barrier between the glue dispensed onto the fabric strip and the rollers, 213 and 222. In this regard, it is advantageous if the width of the paper backing is approximately equal to the width of the rollers.
The top belt assembly 210 is equipped with a front belt lifting unit illustrated in
Referring to
In the embodiment illustrated in
Referring to
As previously noted, the liquid adhesive is dispensed onto the strip of material using a variety of different dispensing mechanisms. A spray nozzle 300 suited for spraying liquid adhesive onto the strip of material is illustrated in
Another embodiment of a liquid adhesive dispensing mechanism is illustrated in
Yet another embodiment of a liquid adhesive dispensing mechanism is illustrated in FIGS. 14A-C
The material guide 521 is adjusted to ensure that the material is guided into place for proper feeding into the nip 514 between top roller 511 and coating roller 510. One feature of material guide 521 is air cylinder 522. Air cylinder 522 is used to lift material guide 521 to remove the material strip (not shown) from contact with the adhesive roller. This is useful when the apparatus is about to be stopped and one does not wish to add adhesive to the remaining material as the final portion of the material strip carrying adhesive is advanced toward the last set of fabric panels before the apparatus is turned off. Other aspects of the material guide 521 are not shown in detail but are readily understood and implemented by one skilled in the art. These features include adjustable sides to guide 521 to accommodate material strips in a variety of widths.
Typically, the rotating speed of the top and bottom rollers is adjusted to control the rate at which the fabric/strip of material/paper is fed into the nip of the apparatus. However, the roller coater is optionally equipped with a stepper motor (not shown). The stepper motor controls the speed at which the strip of material carrying adhesive is dispensed from the roller coater. This speed needs to be compatible with the speed at which the panels are fed into abutting alignment by the apparatus, to ensure that the seam is formed as the panels are fed through the apparatus.
As noted above, one type of adhesive that is contemplated for use in the present invention is a thermoset adhesive that cures permanently when subjected to heat and subsequently cooled. In the context of the present invention, a permanent cure is one where the adhesive, once cured, will not remelt when subjected to elevated temperatures post cure. Typically the cure of such adhesives is accelerated when the adhesive is exposed to moist air. The greater the amount of moisture, the faster the cure. The cure is accelerated if the moist air is cooler (i.e. room temperature or below). While one skilled in the art can design a number of different apparatus that are configured to handle and dispense such adhesives, the following apparatus is one example of such an apparatus. This apparatus is more completely described in U.S. patent application Ser. No. 11/186,061, filed Jul. 22, 2005 and entitled “Method of Garment Manufacturing Method Using Thermosetting Adhesively-Attached Seams” and incorporated by reference herein.
The exemplary apparatus 600 is illustrated in
Referring to
As previously noted, one example of a suitable adhesive is supplied in cans as a thick paste, which must be heated to be converted to the liquid form in which it is used. It takes about 20 to about 30 minutes to heat the adhesive to a temperature sufficient to cause it to melt into a liquid form that is sufficiently fluid to be applied onto the material. As previously noted, the adhesive in liquid form must be kept sealed from the ambient atmosphere to ensure that the adhesive does not begin to cure while in the apparatus. The adhesive can be retained in the apparatus under a blanket of dry, moisture free air or nitrogen and maintained in an uncured state. Since the apparatus has a lower reservoir 621, an empty container 611 can be replaced with a full can and the adhesive in the new can heated and melted before the lower reservoir is empty of adhesive. This ensures continuous operation.
As previously noted, the adhesive cures in the presence of ambient air. In order to affect a more rapid cure, cool, moist air (e.g., room temperature and at least forty percent humidity) is directed onto the newly formed seam. The cool, moist air causes the cure to occur at a faster rate. This allows the seam to set more quickly, making it less likely to come apart when the garment is moved following seam formation.
Referring to
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications, additions and substitutions may be made to the illustrative embodiments without departing from the scope and spirit of the invention, or that other arrangements may be devised without departing from the spirit and scope of the present invention.
This application claims the benefit of the filing date of U.S. Provisional Patent Application No. 60/717,679, filed on Sep. 16, 2005, the disclosure of which is hereby incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60717679 | Sep 2005 | US |
