Woven papermaking drainage fabric having four shed weave pattern and weft threads of alternating diameter

Claim 2

In a Fourdrinier papermaking drainage fabric of interwoven warp and weft threads, the combination of: a four shed weave pattern with both the warp threads and the weft threads passing around one of the other threads on one side of the fabric and then around three of the other threads on the opposite side of the fabric; the warp threads being of substantially uniform diameter; the weft threads being of an all synthetic material and alternating in diameter with every second thread being of a diameter larger than the alternate threads therebetween, the difference in weft thread diameters being at least 10 percent of the smaller weft thread diameter; and crests of warp knuckles on the wear side of the fabric being receded within weft knuckle crests.

Claim 3

A papermaking fabric As in claim 1, wherein both the warp and weft threads are of a synthetic monofilament material.

Claim 4

A papermaking fabric as in claim 1, wherein the diameter of the warp threads is less than the values of the small and large weft thread diameters.

Claim 5

A papermaking fabric as in claim 1, wherein the average surface level of the smaller weft threads is receded into the fabric a greater degree than the average level of the larger weft threads.

Claim 6

In a Fourdrinier papermaking fabric of interwoven warp and weft threads that produce an open mesh for water drainage, the combination of: the warp and weft threads being woven in a repeated four shed pattern and comprised of synthetic material; adjacent weft threads varying in diameter with every other thread being of larger diameter than the threads therebetween and with the minimum difference in weft thread diameters being at least 10 percent of the smallest weft thread diameter; and the large diameter weft threads forming the outermost surface of the wear side, smaller diameter weft threads being recessed within this outermost surface, and warp knuckles on the wear side also being recessed within such outermost surface of the wear side.

Claim 7

In a Fourdrinier papermaking fabric of interwoven warp and weft threads that produce an open mesh for water drainage, the combination of: the warp and weft threads being woven in a repeated four shed pattern and comprised of synthetic material; adjacent weft threads varying in diameter with every other thread being of larger diameter than the threads therebetween and with the minimum difference in weft thread diameters being at least 10 percent of the smallest weft thread diameter; and the large diameter weft threads forming the outermost surface of the wear side, smaller diameter weft threads being recessed within this outermost surface, and warp knuckles on the wear side also being recessed within such outermost surface of the wear side.

Claim 8

A papermaking fabric as in claim 5, with the warp knuckles on the wear side being recessed further within the fabric than the knuckles of the smaller diameter weft threads.

Claim 9

In a paperforming, drainage fabric of interwoven machine direction threads and threads crosswise thereto, such threads being woven of monofilament, synthetic materials in a four shed weave, the combination of: said crosswise threads being composed of different diameter threads of relatively large diameter threads alternating with relatively small diameter threads; the difference in diameter of the relatively large and relatively small crosswise threads being at least 10 percent of the smaller diameter; said crosswise threads having the long knuckles thereof, that traverse more than one machine direction thread, being exposed on the wear side of the fabric; the average level of the long knuckles of said relatively small diameter crosswise threads being recessed within the relatively large diameter crosswise threads; and the knuckles of the machine direction threads being shallower than for the crosswise direction threads, and on the wear side being recessed within the knuckles of the relatively large diameter crosswise threads.

Claim 10

In a paperforming, drainage fabric of interwoven machine direction threads and threads crosswise thereto, such threads being woven of monofilament, synthetic materials in a four shed weave, the combination of: said crosswise threads being composed of different diameter threads of relatively large diameter threads alternating with relatively small diameter threads; the difference in diameter of the relatively large and relatively small crosswise threads being at least 10 percent of the smaller diameter; said crosswise threads having the long knuckles thereof, that traverse more than one machine direction thread, being exposed on the wear side of the fabric; the average level of the long knuckles of said relatively small diameter crosswise threads being recessed within the relatively large diameter crosswise threads; and the knuckles of the machine direction threads being shallower than for the crosswise direction threads, and on the wear side being recessed within the knuckles of the relatively large diameter crosswise threads.