Patent Application
20230249433
The present disclosure relates generally to core tubes and, more particularly, to protective features for embossments in outer surfaces of core tubes.
Cylindrical tubes or cores (collectively referred to herein as “tubes”) are configured for use as a support structure about which a long continuous web of fabric can be wound into a roll. An ordinary paperboard tube has an outer surface that is relatively smooth. For many fabrics, friction between the outer surface and the wound fabric is sufficient to prevent slippage of the fabric along the tube. A challenge can exist in winding such a fabric, such as a nonwoven fabric or the like, about a tube where there is insufficient friction as the fabric is starting to wind about the tube, and the fabric tends to slip relative to the tube as the tube is rotated by the winding equipment. Slippage can also occur during unwinding of the fabric from the tube. Accordingly, tubes may be provided with additional gripping features that increase the adherence of the fabric to the tube outer surface.
Some winding tubes for nonwoven fabrics have embossments on the tube outer surface to grip the fabric. The outer surface layer of these tubes may be formed from an embossed paperboard strip that is helically wound around the exterior of the tube. The embossments are designed to help prevent the fabric from slipping relative to the tube in the longitudinal and circumferential directions. Another type of tube used for nonwoven fabrics has an outer surface layer formed from a helically wound paperboard strip that has a multitude of perforations formed in such a manner that each perforation is surrounded by a small generally conical or “volcano-shaped” region of the outer surface layer that projects radially outwardly such that the outer surface layer defines a prickly surface designed to grab the web of fabric.
Once the paperboard strip is wound around the tube to form the outer surface layer, the embossing or perforation height above the tube outer surface can be diminished as the outer surface layer of the tube comes into contact with supports or rollers that are downstream in the fabrication process from the application of the paper strip. For example, the tube may rest on a V-trough as it moves through the process or be engaged when sections are cut to length from the tube. The diminished height of the embossed or perforated pattern smooths the outer surface layer of the tube and can reduce the effectiveness of the embossments and perforations in engaging the fabric and preventing slippage as the web of fabric is being wound around the tube.
In one aspect of the present disclosure, a tube for winding a web of fabric or similar material thereon is disclosed. The tube may include an inner tube comprising a plurality of inner layers that are wound one upon another about a longitudinal axis of the inner tube and adhered together, the inner tube having a cylindrical inner tube outer surface, an outermost layer formed by a strip of material that is helically wound around the inner tube outer surface, wherein the outermost layer has a tube outer surface and a plurality of raised gripping portions extending radially outward from the tube outer surface by a raised gripping portion distance, and a raised protective strip formed at the outermost layer and wrapping around the outermost layer such that at least a portion of the plurality of raised gripping portions are uncovered and exposed to an exterior of the tube. The raised protective strip may extend radially outward from the tube outer surface by a protective strip distance.
In another aspect of the present disclosure, a tube for winding a web of fabric or other material thereon is disclosed. The tube may include an inner tube comprising a plurality of inner layers that are wound one upon another about a longitudinal axis of the inner tube and adhered together, the inner tube having a cylindrical inner tube outer surface, and an outermost layer formed by a strip of material that is helically wound around the inner tube outer surface. The outermost layer may have a tube outer surface and a plurality of raised gripping portions extending radially outward from the tube outer surface by a raised gripping portion distance, and an overlap seam may be formed by one of the plurality of inner layers or the outermost layer with a first edge of the one of the plurality of inner layers or the outermost layer being applied to an underlying layer and a second edge of the one of the plurality of inner layers or the outermost layer being applied to the one of the plurality of inner layers or the outermost layer over the first edge and overlapping the first edge. The tube may further include a raised protective strip formed in a portion of the outermost layer that overlies the overlap seam. The raised protective strip may extend radially outward from the tube outer surface by a protective strip distance.
In a further aspect of the present disclosure, a method for forming a tube for winding a web of fabric or similar material thereon is disclosed. The method may include forming an inner tube having a plurality of inner layers that are wound one upon another about a longitudinal axis of the inner tube and adhered together, the inner tube having a cylindrical inner tube outer surface, forming an outermost layer from a strip of material that is helically wound around the inner tube outer surface, wherein the outermost layer has a tube outer surface and a plurality of raised gripping portions extending radially outward from the tube outer surface by a raised gripping portion distance, and forming a raised protective strip at the outermost layer that helically wraps around the outermost layer such that at least a portion of the plurality of raised gripping portions are uncovered and exposed to an exterior of the tube. The raised protective strip may extend radially outward from the tube outer surface by a protective strip distance.
Additional aspects are defined by the claims of this patent.
The tube 10 as illustrated further includes an outermost layer 24 formed by a strip 26 of paperboard or other appropriate material (
In the embodiment of
The raised gripping portions 28 are provided in the form of embossments 30 in the strip 26. The embossments 30 may extend radially outward from the tube outer surface 14 by a raised gripping portion distance dRG that allows the embossments 30 to grab the web of fabric and substantially prevent longitudinal and circumferential movement of the fabric relative to the tube outer surface 14 as the web of fabric is wound onto and unwound from the tube 10. Voids created between the inner tube outer surface 22 and the outermost layer 24 by the embossments 30 may be partially or fully filled by the adhesive 36, but it may still be possible for the embossments 30 to be flattened when pressure is applied from the exterior of the tube 10.
The protective strip 12, 34 reduces engagement of the embossments 30 by providing a buffer between the embossments 30 and surfaces (not shown) that come in contact with the tube 10 during fabrication and before the web of fabric is wound onto the tube 10. The protective strip 12, 34 has a thickness so that the protective strip 12, 34 extends radially outward from the tube outer surface 14 by a protective strip distance dPS that is greater than the raised gripping portion distance dRG in the illustrated embodiment. When the tube 10 comes into contact with surfaces, the protective strip 12, 34 engages the surface and radially spaces the embossments 30 to prevent engagement and flattening of the embossments 30. The protective strip 12, 34 may have a longitudinal protective strip length lPS that makes the protective strip 12, 34 sufficiently strong to support the tube 10 on the surface, but narrow enough to minimize any reduction in the number of embossments 30 formed on the outermost layer 24 to provide the necessary contact between the embossments 30 and the web of fabric to prevent slippage. In one embodiment, the strip 26 forming the outermost layer 24 may be approx. 5.0 inches (approx. 12.7 cm) wide, and the strip 34 of material forming the protective strip 12 may have a thickness equal to a protective strip distance dPS within a range of approx. 0.012 inches (approx. 0.305 mm) to approx. 0.030 inches (approximately 0.762 mm), and a width equal to a longitudinal protective strip length lPS of approx. 1.625 inches (approx. 4.127 cm). In this embodiment, the raised gripping portion distance dGP may be less than or equal to the protective strip distance dPS to avoid having the embossments 30 contacted and compressed by the surfaces. These values are exemplary, and those skilled in the art will understand that the dimensions used in a particular application will be determined by the requirements for tube 10 for that application.
In this embodiment, the protective strip 12, 34 is helically wound onto the tube outer surface 14 and affixed thereto by adhesive or other attachment means. The protective strip 12, 34 as shown overlays the seam 38 formed by the edges 40, 42. However, the protective strip 12, 34 may be applied to other longitudinal locations along the outermost layer 24 that do not overlay the seam 38. In other implementations, the protective strip 12, 34 may be helically wound around the tube outer surface 14 at different angle than the strip 26 of material forming the outermost layer 24 such that the protective strip 12, 34 traverses the seam 38 at intermittent locations along the tube 10. Application of such an out-of-angle protective strip 12, 34 to the tube outer surface 14 may occur downstream or out of line from the fabrication process of the tube 10 on a mandrel as illustrated and described below.
As further illustrated in
In this embodiment, the protective strip 12 may allow some level of contact of the raised gripping portions 28 by the surfaces because the raised gripping portion distance dRG is greater than the protective strip distance dPS so that the embossments 30 extend radially outward beyond the protective strip 12. Some compression of the embossments 30 and reduction of the raised gripping portion distance dRG may occur. However, the protective strip 12 and the embossments 30 are dimensioned such that the protective strip 12 limits the compression and the embossments 30 maintain a residual raised gripping portion distance dRG after contact is still sufficient for the embossments 30 to engage the fabric to prevent slippage. For example, in one testing scenario, the embossments 30 had an initial raised gripping portion distance dRG equal to approx. 0.059 inches (1.500 mm), and the protective strip 12 formed by overlapping edges 40, 42 of an outermost layer 24 that was 0.020 inches (0.508 mm) had a protective strip distance dPS equal to approx. 0.020 inches (0.508 mm). After engagement of the tube 10 by test surfaces, the embossments 30 had a residual raised gripping portion distance dRG equal to approx. 0.038 inches (0.965 mm), which may be sufficient to provide the necessary grip to prevent slippage of the fabric. While only being illustrated in the embodiment of
Referring to
An apparatus and process for making the tube 10 of
The strip 26 of material having the raised gripping portions 28 formed thereon is advanced toward the inner tube 16 and the mandrel 70 at a suitable winding angle α that is determined based on the diameter of the inner tube 16 and the width of the strip 26 so that the strip 26 will be wound about the inner tube 16 in a helical fashion to form the outermost layer 24 in such a way that the opposite edges 40, 42 of the successive helical turns of the strip 26 either abut or have a slight gap therebetween at the seam 38. It is usually desired to avoid having the edges 40, 42 overlap because an overlap region creates a bump that can adversely affect the attachment of the thin strip 34 to the tube outer surface 14. Where overlap of the edges 40, 42 may occur, the edges 40, 42 of the strip 26 may be skived to reduce the thickness of the strip 26 so that the thickness of the outermost layer 24 at the seam 38 is approximately the same as the thickness of the remainder of the strip 26 and the overlap does not form a bump. The strip 26 has the adhesive 36 applied to the inner surface 52 that faces the inner tube outer surface 22 by a suitable adhesive applicator (not shown) located between the supply roll (not shown) for the strip 26 and the inner tube 16.
In the illustrated embodiment, raised gripping portions 28 are not formed proximate the edges 40, 42 of the strip 26 so that the tube outer surface 14 proximate the seam 38 is relatively flat and without undulations created by the raised gripping portions 28 in the areas between adjacent turns of the seam 38. In alternate embodiments, however, the raised gripping portions 28 may be formed in the strip 26 out to the edges 40, 42, and the protective strip 12 may be applied over and affixed to areas having raised gripping portions 28. The process shown in
The tubes 10 incorporating protective strips 12 in accordance with the present disclosure better maintain the radial projection of the raised gripping portions 28 and better preserve the ability of the tube outer surface 14 to grab a web of material being wound thereon and prevent longitudinal and circumferential slippage of the material along the tube outer surface 14. The raised area provided by the protective strip 12 allows the tube 10 to rest on supports or other surfaces without applying pressure to the raised gripping portions 28 that tends to flatten the tube outer surface 14. This also minimizes the risk of having the adhesive 36 bleed through the outermost layer 24 and be transferred to the support surfaces. In this way, a small area of the raised gripping portions 28 may be sacrificed to provide better quality of embossments 30, perforations 32 or other raised gripping portions 28 on the remainder of the tube outer surface 14.
While the preceding text sets forth a detailed description of numerous different embodiments, it should be understood that the legal scope of protection is defined by the words of the claims set forth at the end of this patent. The detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims defining the scope of protection.
It should also be understood that, unless a term was expressly defined herein, there is no intent to limit the meaning of that term, either expressly or by implication, beyond its plain or ordinary meaning, and such term should not be interpreted to be limited in scope based on any statement made in any section of this patent (other than the language of the claims). To the extent that any term recited in the claims at the end of this patent is referred to herein in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term be limited, by implication or otherwise, to that single meaning.
