Textiles: weaving – Fabrics – Drier felts
Patent
1994-11-09
1995-10-17
Falik, Andy
Textiles: weaving
Fabrics
Drier felts
D03D 304
Patent
active
054581613
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to an improved, high strength, high loop density, woven back pin seam for use in joining the ends of papermakers' and like fabrics.
(b) Description of the Prior Art
Woven fabrics, intended for use in either the forming, pressing or drying sections of paper making machines, are usually rendered endless by one of three methods:
1) endless weaving, such as is described in U.S. Pat. No. 2,903,021;
2) joining the opposing ends of a flat woven fabric with a permanent seam, such as is described in U.S. Pat. No. 3,366,355; U.S. Pat. No. 3,596,858 or U.S. Pat. No. 3,700,194; or
3) joining the opposing ends of a flat woven fabric by forming small loops in the opposing fabric ends and then interdigitating these loop ends during installation of the fabric on the papermaking machine to form a passageway through which a pintle is inserted to form a hinge-type joint. Such seams are described, for example, in U.S. Pat. No. 4,182,381, U.S. Pat. No. 4,469,142 and U.S. Pat. No. 5,092,373.
The present invention is concerned with the last of these methods. Although several types of these seams are presently in use on papermaking fabrics, the most desirable type of seam, which produces the least mark in the paper web in contact with it, is a woven back pin seam, wherein the warps of the fabric are used to form the loops which receive the joining pintle. The loops are formed by weaving back the ends of some of the warps into a nearby warp path in the fabric, in registration with the fabric weave. Such seams are well known in the prior art, and are referred to in the trade, and henceforth in this disclosure, as pin seams.
Because of their length, dryer fabrics are almost always joined on the paper machine with an on-machine seam, and therefore this invention applies particularly to dryer fabrics. However, press fabrics are also often joined by pin seams, as are some coarse forming fabrics, and the invention applies equally well to these types of fabrics.
It is well known that most prior art pin seams are formed in fabrics woven in 4-shed or 8-shed weave patterns. Such designs are particularly well suited to pin seaming due to their even number of sheds. The pin seam is typically made by removing a predetermined number of weft strands from each end of the fabric and when reweaving the crimped warp strands, which now project from both fabric ends, through a plurality of added weft, in a manner that is well known. The weft strands are generally chosen from a group consisting of thermoplastic polymer monofilaments, spun yarns, multifilament yarns, plied monofilaments, or combinations thereof. A warp strand is typically folded back and interwoven partway into a nearby warp path until it reaches the warp strand normally residing in that path, which is also rewoven into the added weft strands. Both strands are clipped off closely to the surface of the fabric to provide termination points at various distances from the last original undisturbed weft strand in the fabric end. One-half of these folded back warp strands are bent around a loop-forming rod placed adjacent the last added weft strand to form pintle loops. The remaining folded back warp strands are bent around the last added weft to form non-load bearing loops. The same method is employed at the opposing fabric end so as to produce seaming loops which are identical to those made at the first fabric end. The seam is then closed by interdigitating the two sets of pintle loops, and inserting the pintle. It will thus be seen that only 50% of the available warp strands from each opposing fabric end are used to form the load bearing pintle loops in these prior art pin seams.
Prior art pin seams suffer from several disadvantages, including, but not limited to the following:
1) the difficulty with which the fabric ends are interdigitated and the pintle inserted during installation on the paper machine,
2) fabric failures due to insufficient strength in the region of the seam, and
3) marking of the moist
REFERENCES:
patent: 803659 (1905-11-01), Allen
patent: 2255452 (1941-09-01), Pink
patent: 2903021 (1959-09-01), Holden et al.
patent: 3366355 (1968-01-01), Haller
patent: 3596858 (1971-08-01), Curtis
patent: 3700194 (1972-10-01), MacBean
patent: 4026331 (1977-05-01), Lees et al.
patent: 4035872 (1977-07-01), MacBean
patent: 4182381 (1980-01-01), Gisbourne
patent: 4286631 (1981-09-01), Strandly
patent: 4346138 (1982-08-01), Lefferts
patent: 4438789 (1984-03-01), MacBean
patent: 4469142 (1984-09-01), Harwood
patent: 4535824 (1985-08-01), Kerber et al.
patent: 4945612 (1990-08-01), Talonen
patent: 4991630 (1991-02-01), Penven
patent: 5062216 (1991-11-01), Hannigan
patent: 5089324 (1992-02-01), Jackson
patent: 5092373 (1992-03-01), Lee
patent: 5188884 (1993-02-01), Smith
Falik Andy
JWI Ltd.
Wilkes Robert A.
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