Machine side layer weave design for composite forming fabrics

Abstract

A machine side layer weave design for use in woven composite fabrics, particularly papermakers forming fabrics having differing weave designs on each planar surface is provided. The composite fabric is comprised of two sets of weft yarns interwoven with at least one system of warp yarns. A first set of weft yarns is interwoven with the at least one system of warp yarns to form the paper side layer, while the second set of weft yarns is interwoven with the at least one system of warp yarns to form the machine side layer. In each repeat of the machine side layer weave design, at least 50% of the warp yarns pass under two adjacent weft yarns on the machine side of the fabric to form a double warp knuckle, and each double warp knuckle is bounded on either side by a single warp knuckle formed on each of the first and second weft passed under by the double warp knuckle. Further, in each repeat of the weave, each weft yarn is passed under by two adjacent warp yarns to form two adjacent single warp knuckles. In one embodiment, all of the warp yarns form double warp knuckles; in an alternate embodiment, 50% of the warp yarns form double warp knuckles. The knuckles are evenly distributed across the machine side surface so as to minimize any propensity for guiding. The machine side layer weave design of the invention is suitable for use in any composite fabric and is effective in minimizing or eliminating fabric edge curl, a problem common in fabrics of this type.

1 . A flat woven composite forming fabric for use in a forming section of a papermaking machine, the fabric comprising:
 i. a first set of weft yarns located on a paper receiving side (PS) of the fabric,   ii. a second set of weft yarns located on a machine contacting surface side (MS) of the fabric, and   iii. at least a first system of warp yarns interwoven with the weft yarns of the first and second sets of weft yarns according to an overall weave pattern for the composite fabric which provides for differing weave patterns on each of the PS and MS sides of the fabric, wherein:   
     in each repeat of the weave pattern for the MS of the flat woven composite forming fabric, the warp yarns pass together in adjacent pairs under all of the weft yarns in the second set of weft yarns to form two adjacent single warp knuckles at each MS weft interlace point. 
   
   
       2 . Fabric according to  claim 1 , wherein at least 50% of the warp yarns include double warp knuckles formed by passing under two adjacent ones of the weft yarns. 
   
   
       3 . Fabric according to  claim 1 , wherein 100% of the warp yarns include double warp knuckles formed by passing under two adjacent ones of the weft yarns in the second set of weft yarns. 
   
   
       4 . Fabric according to  claim 3 , wherein one of the single warp knuckles of a next adjacent one of the warp yarns is located on each lateral side of each of the double warp knuckles. 
   
   
       5 . Fabric according to  claim 4 , wherein a first one of the single warp knuckles is formed under a first of the two weft yarns passed under by the warp yarn forming the double warp knuckle, while a second one of the single warp knuckles is formed under a second of the two weft yarns passed under by the warp yarn forming the double warp knuckle. 
   
   
       6 . Fabric according to  claim 1 , wherein a repeating pattern of the two adjacent single warp knuckles is uniformly distributed over the MS surface of the fabric, offset from diagonal twill lines. 
   
   
       7 . Fabric according to  claim 1 , wherein the overall weave pattern is a 24-shed design. 
   
   
       8 . Fabric according to  claim 7 , wherein the MS weave is woven according to a 4 or 6 shed design. 
   
   
       9 . Fabric according to  claim 7 , wherein the MS is woven according to a 12-shed design 
   
   
       10 . Fabric according to  claim 1 , wherein the overall weave pattern is a 20-shed design. 
   
   
       11 . Fabric according to  claim 10 , wherein the MS weave is woven according to a 5-shed design. 
   
   
       12 . Fabric according to  claim 1 , wherein the overall weave pattern is a 16-shed design. 
   
   
       13 . Fabric according to  claim 11 , wherein the MS weave is woven according to a 4-shed design. 
   
   
       14 . Fabric according to  claim 12 , wherein the MS is woven according to a 12-shed design. 
   
   
       15 . Fabric according to  claim 1 , further comprising a second system of warp yarns interwoven with the first set of weft yarns located on the PS of the fabric. 
   
   
       16 . Fabric according to  claim 1 , wherein the warp knuckles on the MS are all arranged in groups of four knuckles in a Z or reverse Z pattern. 
   
   
       17 . Fabric of  claim 1 , wherein the MS weft yarns include MS floats over at least 4 warp yarns. 
   
   
       18 . A flat woven composite forming fabric for use in a forming section of a papermaking machine, the fabric comprising:
 i. a first set of weft yarns located on a paper receiving side (PS) of the fabric,   ii. a second set of weft yarns located on a machine contacting surface side (MS) of the fabric, and   iii. at least a first system of warp yarns interwoven with the weft yarns of the first and second sets of weft yarns according to an overall weave pattern for the composite fabric which provides for differing weave patterns on each of the PS and MS sides of the fabric, wherein:   the warp yarns weave under the weft yarns in the second set of weft yarns to form MS warp knuckles arranged in groups of four adjacent knuckles in a Z or reverse Z pattern, the groups being generally uniformly spaced over the MS of the fabric.   
   
   
       19 . A woven composite fabric for use in a papermaking machine, the fabric comprising:
 i. a first set of cross-direction yarns located on a paper receiving side (PS) of the fabric,   ii. a second set of cross-direction yarns located on a machine contacting surface side (MS) of the fabric, and   iii. at least a first system of machine direction yarns interwoven with the cross-direction yarns of the first and second sets of cross-direction yarns according to an overall weave pattern for the composite fabric which provides for differing weave patterns on each of the PS and MS sides of the fabric, wherein:   in each repeat of the weave pattern for the MS of the composite fabric, the machine direction yarns pass together in adjacent pairs under all of the cross-direction yarns in the second set of cross-direction yarns to form two adjacent single warp knuckles at each MS cross-direction yarn interlace point.