US 3207659 A
Description (OCR text may contain errors)
Sept. 21, 1965 J. R. WAGNER 3 ,6
- METHOD OF MAKING PAPERMAKER'S FABRIC AND THE FINISHED FABRIC Filed Jan. 22, 19.63
fizz/17m JOJZP/y $0554 7 11/ 6 95 W, M 7M Y a 207 659 METHOD or MAKING RAPERMAKERS FABRIC AND THE FINISHED FABRIC Joseph Robert Wagner, Knoxville, Tenn., assignor to Huyck Corporation, Stamford, Conn., a corporation of New York 7 Filed Jan. 22, 1963, Ser. No. 253,129 4 Claims. (Cl. 162348) The present invention relates to papermakers fabric and in particular to 'Fourdrinier fabric and its method of 'manufacture in which the fabric contracts in the cross dire'ction upon being stretched in the machine direction.
The fabric may be woven substantially as shown and described in Holden and Schilf Patent No. 2,903,021 issued September 8, 1959 for Fourdrinier Cloth. The fabric may comprise warp yarns and weft yarns woven into any desired or suitable pattern in which the warps and wefts are both preferably made of resilient synthetic fibers and may be made of polyamide fibers such as nylon, polyester fibers such as Dacron, acrylic fibers such as Orlon, Dynel and Acrilan, or copolymer fibers such as Saran. The Fourdrinier cloths made by the processes of the Holden et al., patent had relatively straight wefts and curved warps. This is the normal result of weaving in a conventional loom.
It has now been discovered that under certain circumstances it is preferable to have the warp yarns straighter and the weft yarns crimped in order to provide a forming fabric that will contract substantially in the 'cross direction upon being stretched in the machine direction. This property is' desirable for certain applications,
vsuch as for making stretchable paper in accordance with the teachings of the copending application of Gordon J. Chalmers, Charles Allen Lee and Joseph Robert Wagner Serial No. 253,112 filed January 22, 1963, for Papermaking Method and Apparatus. Incompressible material, such as rubber, contracts in one direction when stretched in the other direction in order-to remain at a constant volume. .This is evident in the stretching of a rubber band, which becomes thinner when stretched lengthwise. Although the stretching of the individual weft yarns may cause these yarns to become thinner, this'in itself does not contract the fabric. The straightening of the weft yarns, however, forces the warp yarns to take a more tortuous path across the fabric so that they do not extend so far in the cross direction. In accordance with the present invention the fabric is made with the Warp yarns relatively straightand the weft yarns crimped to some degree, with the weft yarns extending in the machine direction, that is, in the direction of the endless belt formed by the fabric. Thus, when the belt is in its relaxed condition, the warp yarns extend to their full dimension in the cross direction. Stretching of the weft yarns then straightens them and forces the warp yarns to take a more tortuous path, thus contracting the fabric in the cross direction. In fabrics made pursuant to the method of Holden et al., the weft yarns were substantially straight and stretching produced but relatively small contraction of the fabric in the cross direction.
To make the desired fabric, the wefts and warps may be wovenin a conventional manner. The fabric is then placed in substantial tension in the warp direction while exerting relatively little tension in the Weft direction. This straightens the warp yarns and crimps the Weft yarns. While in such condition, the weft yarns are bonded to the warp yarns, as by the thermal or chemical treatment disclosed by Holden et al.
It is therefore. a primary object of the present invention to provide an endless Fourdrinier fabric of synthetic material that contracts in the cross direction when stretched in the machine direction. It is a further object of the 3,207,659 Patented Sept. 21 1 965 present invention to provide a method of making such fabric. These and further objects of the present invention will become apparent from the following description when read in connection with the accompanying drawings in which:
FIGURE 1 is aperspective view of a Fourdrinier fabric embodying the present invention; I
.wefts 10 thus transversely severing the warps 12.
FIGURE 2 is a somewhat diagrammatic representation of a loom arranged for weaving of a Fourdrinier fabric in accordance with this invention;
FIGURE 3 is a section along the line 3-3 in FIG- URE l; and
"FIGURE 4 is a section along the line 4-4 in FIG- URE 1.
Referring now to the drawings, there is illustrated in FIGURE 1 an endless Fourdrinier fabric made up of interwoven yarns 10 and 12 extending respectively lengthwise and transversely of the width of theendless belt.
Referring now to FIGURE 2, the material from which theendless belt shown in FIGURE 1 is made is shown emerging frOm'a loom 14. In said FIGURE 2 it will be observed that yarns 10 extend transversely of the loom and thus have been woven into the while the yarns 12 extend lengthwise of the loom and thus have been woven as warps. The length of cloth emerging from the loom 14 is tubular and any well known arrangement for the weaving of tubular fabrics may 'be employed. For example, the warps 12 may be arranged in harnesses to form two sheds for the upper and lower portions 16 and 18, respectively, and in special harnesses or guides to form the continuous end zones 20. The wefts 10 may be supplied by one or more shuttles. In the event that a single shuttle is used, the weft 10 is projected through one of the sheds and is returned, without cutting, through the other shed in the next beat of the loom, thus forming a continuous helix of the weft yarn. If a plurality of shuttles are used they will follow one another in sequence with out cutting at either end of the loom whereby the wefts 10 are formed into a plurality of con 'tinuous parallel helices. In either event each yarn which is woven as a weft forms a helix which is continuous for a large number of beats of the loom, limited only by the capacity of the bobbins used in the shuttles. When a bobbin is exhausted and must be replaced, the ends of the old and new weft yarns for that particular shuttle will be overlapped as is customary in the weaving of endless tubular fabrics. In FIGURE 2 a single shuttle 11 is shown resting in the shuttle box 13 at the drive end of the loom.
The endless belt shown in FIGURE 1 is cut to suitable width by cutting the fabric in a direction parallel with the As shown in FIGURE 1, the warps 12 extend transversely of the width of the belt and the weft or wefts 10 extend in substantially continuous form throughout the length of the belt. It will be apparent that each continuous helical weft 10 will be severed at one place along each of the edges of the belt and that the severed ends of the warps 12 will form raw cut edges 22 and 24. It will be understood that such edges may be reinforced or bound in any suitable fashion. For example, they may be stitched or immersed in a settable adhesive or binding material such as a plastic or rubber or synthetic rubber or fused by heat from a fiame or heated surface to insure stability along the edges 22 and 24.
It is a normal incident of weaving in a conventional loom that the warps assume a generally curved shape whereas the wefts remain substantially straight. Inasmuch as the warps are not in the machine direction or direction of the belt, this is the reverse of the desired condition. The fabric after weaving is therefore stretched in the cross direction so as to straighten the warps, as shown cloth as wefts or fillers,
3 in FIGURE 3. Relatively little tension is exerted in the machine direction whereupon the wefts take a relatively curved shape, as shown in FIGURE 4. The stretch may be achieved by placing the fabric on tenter pins. While in such condition, the fabric is treated to form permanent bonds at each intersection of the warps and wefts. This may be achieved as described in the Holden et al. patent by treatment of the fabric with a suitable bonding or adhesive material such as settable resin. The fabrics may be immersed, either before or after cutting to a suitable width, in settable resinous material which is thereafter set to form bonds at each crossing. The bonds thus formed not onlystabiliz'e the body of the fabric but also serve to reduce likelihood of ra'velling of the edges. The bonding at the crossings may also be achieved by utilizing the thermoplastic properties of the synthetic fibers of which the fabric is made. That is, the fabric may be heated to suitable temperature at which the fibers become sufiiciently tacky to form the desired bonds at the crossings, when cooled.
Many different types of synthetic yarns can be used. As mentioned above, these may be polyamide fibers such asnylon, polyester fibers such as Dacron, acrylic fibers such as Orlon, Dynel or Acrilan, or copolymers such 'as Saran. These yarns may be monofilament yarns, multifilament yarns or staple yarns, depending upon particular desired properties or uses for the fabric. The word yarns is used herein to include all of these constructions.
As an example, forming fabric was woven with three ply nylon warp yarns composed of 10 filaments totaling 140 denier in each ply. The weft was three ply Dacron yarn having 34 filaments totaling 70 denier in each ply. The fabric was bonded while stretched about 7 percent in the cross section direction but while under relatively low tension in the machine direction. Thereafter, at a tension of pounds per lineal inch in the machine direction, the finished fabric contracted 7 /2% in the cross direction.
This is by way of example only, particular yarns being selected in accordance with the particular type of paper or similar product which is to be formed as well as the particular machine upon which it is to be used and its'speed of operation. The important features of the resulting fabrics are that they have warp yarns that are relatively straight as compared to the warp yarns of Holden et al., and have weft yarns that are crimped about the warp yarns rather than being straight as shown by Holden et a1. It is not necessary that the warp yarns be made completely straight or even as straight as the weft yarns. It should be noted that the word straighten" as used herein does not means to make absolutely straight but includes making more nearly straight than before. The invention is,
therefore, limited only as set forth in the following claims.
What is claimed is: I
1. A method of making fabrics for papermaking machines comprising weaving warp and weft yarns of resilient synthetic fiber into an endless fabric in which the weft yarns extend endlessly in the machine direction of the fabric and the warp yarns extend transversely thereto in the cross direction, placing the fabric in suflicient tension in the cross direction to straighten the warp yarns while placing the fabric in relatively low tension in the machine direction whereby the straightening of the warp yarns causes the weft yarns to become crimped, and bonding the weft yarns to the warp yarns while under such tension.
2. A method of manufacturing fabrics for papermaking and similar machines comprising weaving a fabric as a continuous tube having warp and weft yarns of synthetic material and with each weft yarn forming a substantially continuous helix extending circumferentially of said tube, selecting the synthetic material for said yarns from the group consisting of monofilaments, multifilaments and staple fibers of polyamide, polyester, acrylic and copoly mer fiber forming materials, cutting said fabric tube along lines substantially parallel with said wefts to form endless fabric belts in which said wefts extend lengthwise of said belts in the machine direction, placing said belts in substantial tension in the cross direction while placing said belts in relatively low tension in the machine direction whereby said warp yarns are straightened and said weft yarns are crimped, and bonding said warp and weft yarns together at their crossings while under such tension.
3. A fabric for papermaking machines comprising an endless belt formed of interwoven warp and weft yarns in which the warp yarns extend in the cross direction across the width of the belt and the weft yarns are crimped around said warp yarns and extend in the machine direction of the belt as a substantially continuous helix progressing from one edge of the belt to the other, said warp yarns being bonded to said weft yarns at their crossings, whereby said fabric contracts substantially in the cross direction when placed in tension in the machine direction.
4. A fabric for papermaking machines comprising an endless belt formed of interwoven warp and weft yarns in which the warp yarns extend relatively straight in the cross direction across the width of the belt and the weft yarns are crimped around said warp yarns and extend in the machine direction of the belt as a substantially continuous helix progressing from one edge of the belt to the other, all of said interwoven yarns consisting substantially entirely of at least one synthetic material selected from the group consisting of monofilaments, multifilaments and staple fibers of polyamide, polyester, acrylic and copolymer fiber forming materials, and said warp yarns being bonded to said weft yarns at their crossings, whereby said fabric contracts substantially in the cross direction when placed in tension in the machine direction.
References Cited by the Examiner UNITED STATES PATENTS 2,903,021 9/59 Holden et a] 139383 3,030,690 4/62 Mizell 139383 FOREIGN PATENTS 643,915 7/62 Canada.
DONALD W. PARKER, Primary Examiner. RUSSELL C. MADER, Examiner.