US3166884A - Non-elastic extensible yarn - Google Patents

Description

Jan. 26, 1965 M. STElNE R ETAL V 3,156,884

NON-ELASTIC EXTENSIBLE YARN Filed Aug. 5, 1960 I;VI/ENTOR. i MAX STE/IVER & y CARL l-T JACKSON Arrwmsys United States Patent Oil ice 3,166,834 NON-ELASTIC EXTENSEBLE YARN Max Steiner, Lincoln, and (Jarl F. Eackson, Cumberland,

RL, assignors to fiwens-flormng Fiherglas Corporation, a corporation of Delaware Filed Aug. 5, 196 3, Ser. No. 47,810 4 Qlairns. (til. 57-149) This invention relates to extensible fabrics, and to methods, looms, and yarn for weaving such fabrics. The woven products of this invention are preferably composed of fibrous glass yarns and are particularly intended for reinforcement of molded plastic articles. However, various features of the invention are of value in connection with stretchable fabrics built with yarns of other compositions and for purposes other than the reinforcement of plastics.

The fibrous glass extensible fabric and the roving yarn disclosed in the US. application, Serial No. 754,203, filed August 11, 1958, now US. Patent No. 2,975,503, by Bacon and Nemeyer are of the types with which the subject invention is especially concerned.

The roving-like yarn described in the Bacon and Nemeyer application is formed by looping a strand back and forth in multiple courses which are superimposed but in progressively advancing relationship with a slight integrating entanglement therebetween. Preferably, each course of strand is not more than several inches long and there is a uniform quantity, desirably between forty and eighty, of adjacent courses along the length of the yarn, with each course terminating in open loops.

The yield of the fabric constructed from such easily drafted yarn enables the fabric to conform under manual or mechanical pressure to the shape of a plastic mold, and the open loops in the yarn are adapted to receive increments of plastic to finally fix the fabric in nonstretchable condition and with excellent tensile strength.

However, the weaving of this fabric, because of the inherent elongating tendency of the special yarn, and the variantly extending strand loops, has posed serious problems. When used as warp, the yarn stretches too readily under weaving tensions and the loops promote inter-yarn entanglements which disrupt the weaving operation. As a consequence, this type of extensible yarn has been restricted generally to employment as fill yarn; and the fabric production is, even then, slower than commercially desirable.

It is then a prime object of this invention to provide means for avoiding these difiiculties in the fabrication of fabric with such extensible yarns.

More specifically, an object of this invention is the provision of a loom and weaving method for efficiently handling extensible yarns.

A further object of the invention is the provision of a yarn adapted to permit trouble-free weaving while capable of producing a fabric having stretchable properties.

Another important object is to provide an improved extensible fabric.

As will be described more completely hereafter, with reference to the accompanying drawings, these and other objects are attained at least in part through a loom with means for separating the warp yarns as they approach the heddles through means for avoiding engagement by the fill needle with loops in the warp yarn; and through extensible yarns having elements contributing temporary tensile strength thereto.

In the drawings,

FIGURE 1 is a diagrammatic plan view of a needleloom embodying features of this invention;

BJfififiM Patented Jan. 26, 1965 FIGURE 2 is a side elevation of the loom of FIG- URE 1;

FIGURE 3 is an enlarged side view of the forward end of the fill needle of the loom of FIGURES 1 and 2;

FIGURE 4 is a top view of the portion of the fill needle shown in FIGURE 3; and

FIGURE 5 is a perspective view on an enlarged scale, of a short piece of yarn constructed according to the invention.

Referring to the drawings in more detail, the loom ll) of FIGURES l and 2 includes a rack or creel 11 for holding supply packages 12 of warp yarn 13. The strands of yarn 13 are alignedfand properly spaced by being passed through the comb or raddle 15. The array of yarn 13 then passes over guide roll 1'7, under the yarn tensioning roll 19 and over the whip roll 20.

As the strands of yarn move forwardly from the whip roll 20 they are individually isolated to prevent entangling contact between adjoining strands by the separator plates 22, which are vertically suspended from the two support bars 23. The plates 22 are preferably of tough cardboard but may be composed of thin, smoothfinished plastic or metal stock.

Alternate sets of the strands of the yarn 13 are moved upwardly and downwardly between the plates 22 as they follow the vertical reciprocation of the heddle-carrying harnesses Z4 and 25. After being drawn through the eyelets of the heddles, the'latter being preferably of flat, stainless steel, the yarn travels through the dents of the fill beater 27.

The weft or fill yarn 29, in this example, has the same basic looped strand structure of the warp yarn 13. This fill yarn 29 is delivered through a guide ring 36 for repeated transverse feeding movements, with the fill needle 31, through the successive sheds 32 formed between sets of the warp yarn.

. The fill needle 31 projects from a carriage 34, diagrammatically shown as driven on a track of parallel bars 35 by a connecting rod 37 from any suitable drivmg means.

The woven fabric 46, produced by the picks of the fill yarn threaded between alternate strands of the Warp and pushed into place by lateral movement of the reed or heater 27, first travels over the breast beam 42. The fabric then passes down under the cloth beam 45, and over the take-up roll 46 to be wound on the cloth roll 47.

With a fill needle of conventional design it has been found that loops of strands hanging down from the warp yarn 13 were frequently caught by the point of the needle. This creates major flaws in the fabric or requires stopping of the weaving operation to release and realign the warp yarns and to splice broken ends. These troubles occur so repeatedly and are so serious that they make such weaving very unproductive. The needle 31 provided by this invention, as later brought out, is designed to circumvent these and other related difiiculties.

On each projection of the needle through the shed 3.2, a tapered finger from conventional mechanism 49 opens the gap between the needle and the portion of the yarn extending along the bottom of the needle for the passage of the selvage shuttle 59. The indentation 52 on the bottom of the needle provides space for the initial entry of the tapered finger.

By being enlarged to a diameter of one inch or more and by having a rounded point 54 the needle does not engage wayward loops of the warp yarn when passing through the shed 32. Also by having the forward section of the needle in front of the eye 55 lengthened to'approximately two and one half inches the tying in of the fill yarn with the selvage yarn is more positively accomplished. A groove 56 along the top of the needle receives and protects the upper course of the double pick of fill yarn.

With the improved features comprising the warp separators 22 and the novel needle structure, not only is the operation of the loom free of trouble but a very satisfactory weaving speed may be attained.

One form of fabric produced by this loom has four warp ends per inch of eighty end rovings and three double picks per inch of forty end rovings. These rovings are composed of looped strands having a length of 14,000 yards per pound. The strands are gatherings of either four hundred continuous glass filaments of a diameter of approximately thinty-seven one hundred thousandths of an inch or eight hundred filaments of a diameter in the region of twenty-seven one hundred thousandths of an inch.

Strands of these specifications are preferred from a practical standpoint for creating the extensible rovinglike yarns, although somewhat improved fabrics may be produced with strands composed of glass filaments of smaller size.

The fabric so constructed has a weight of twenty six ounces per square yard and has good weave stability with superior resistance to raveling, when cut. It has excellent wetting property when impregnated with plastic and as a plastic reinforcement its strength pattern is desirably more circular in nature than those of other fibrous glass fabrics. The drape and mold drawing characteristics of the fabric are also excellent.

For both facilitating the weaving action and for improving -the glass and plastic cohering association the strands are lightly sized with a very thin coating solution of polyvinyl acetate.

Increased weaving rates (running above sixty picks per iinute), and more tightly woven fabrics may be secured through the utilization of special looped-strand rovings provided by this invention. One form of such a yarn is depicted on a greatly enlarged scale, in FIGURE 5. As there shown the yarn 59 has a main body portion 619 of 14,000 yards-per-pound strand doubled back and forth upon itself inlooped courses averaging eighty in number at any point across the yarn. The straight longitudinally displaceable courses 62 of the strand progressively overlap each other. This is indicated by the progression of loops terminating the courses. For instance, the loops 63a, 63b and 63c may be considered the terminal loops of three closely related but not immediately successive courses, the main portions of which would extend along the yarn toward the left of FIGURE 5. Similarly, the loops 64a, 64b and 640 mark the ends of near-successive, overlapping courses the main portions of which would extend along the yarn toward the right of FIGURE 5.

Centered along the longitudinal axis of the yarn 59 are four continuous, unlooped strands 61. These may have the same specifications as the repeatedly folded strand of which the main portion 69 of the yarn is composed. These center strands, individually, have a tensile strength averaging two and six tenths of a pound, and therefore together contribute about ten pounds of added tensile strength to the yarn. This is well above that required to withstand the weaving pulling forces.

With four such yarns to the inch the fabric will resist a stretching force of forty pounds per inch of width before these center strands break. This is more resistance to extension than is desired when manually forcing the fabric into conforming relationship with the contours of a mold, and so when the fabric is intended for such manual positioning center strands of less strength are utilized. These provide sufficient temporary strength during the weaving operation and yet break and permit yielding of the fabric under molding conforming installation.

In matched die molding in which the fabrics serve as reinforcing elements, a minimum molding pressure of one hundred pounds per square inch is normally available and this is well over that required to sever the continuous J center strands and thus to release the fabric and allow it to stretch in accord with the mold shape.

Continuous strands of other composition than glass may of course be employed as a core of the yarns to provide the temporary and preliminary tautness during the Weaving process. Such alternate compositions may include most of the natural and synthetic fibrous materials such as cotton, rayon or nylon. These strands have fracturing points Well below that of comparable fibrous glass strands, so the quantity utilized must be greater to obtain equal resistance. The synthetic strands may have the same resinous base {c.g. acrylic) as the plastic with which the fabric is to be combined and may therefore be dissolved instead of broken.

Thermoplastic center strands, such as those of polyvinyl chlorideacetate and of polyethylenes may be caused to release the yarn through softening by heat applied to the dies. Altcrnately, reinforcing center strands such as cellulose acetate and polyvinyl chloride-acetate may be removed by ketones or other organic solvents.

The feature of the invention involving a temporary tensionresisting element in an otherwise stretchable yarn is also of benefit in facilitating the weaving of elastic fabric. in this adaptation of the invention one or more fracturable, dissolvable or meltable strengthening strands are combined with elastorneric threads to produce a yarn capable of undergoing the weaving stresses. The continuous strands in the resulting fabric are then broken or removed by solvents, or disintegrated by heating to establish the desired elasticity of the fabric.

While this invention is directed principally to the production of fabric with extensible yarns in both the warp and fill, features of the invention are also of value in weaving fabrics with various combinations of extensible and non-extensible yarns. The most common combination would be to use non-extensible yarns in the warp and the extensible form in the fill. For special purposes alternate sets of the two types of yarns may be arranged in either the warp or the fill.

In summary, this invention has provided a weaving method and loom particularly adapted for handling loopy yarns by separating the warp yarns during their vertical reciprocation between the whip roll and the heddles and by employing an oversize needle having an elongated and rounded forward end. The invention has further improved the Weaving of such yarns as well as of other extensible yarns by incorporating elements therein having tensile strength of a transient nature. An end product of the invention is the inherently extensible fabric with non-extensible yarn elements subject to disintegration.

Modifications and substitutions in the particular embodiments of the invention disclosed herein will occur to those skilled in the arts involved, without departing from the spirit of the invention nor the confines of the accompanying claims.

We claim:

1. A non-elastic yarn for producing a fabric for reinforcing molded plastic products and which is manually non-extensible but extensible under the high pressure of a die molding operation, said yarn including generally parallel short courses of forty or more fibrous glass strands in adjacent relation crosswise of the yarn, said short course terminating in loops, and said courses progressively overlapping each other longitudinally of the yarn and being relatively and easily displaceaole under a stretching force longitudinally of the yarn, and non-extensible, non-looped continuous fibrous glass strands extending in close array, unentangled, unvaryingly and uninterruptedly along the axis of the yarn, said continuous strands having individually a tensile strength of at least two pounds and thus providing the yarn and the fabric produced therefrom with resistance to tensile forces to which the yarn and the fabric may be submitted before the fabric is used as a reinforcement for plastic in a die molding operation, but said continuous strands of the fabric being fracturable under the pressure of such molding operation.

2. A non-elastic yarn for producing a reinforcing fabric for molded plastic products, said fabric being nonextensible under weaving and handling stresses but extensible for compliance with the shape of the mold under pressure in a molding operation, said yarn including generally parallel short courses of a high plurality of fibrous glass strands in adjacent relation crosswise of the yarn, said short courses of strands terminating in loops, and said courses progressively overlapping each other longitudinally of the yarn and being relatively and easily displaceable under a stretching force longitudinally of the yarn, and non-extensible, non-looped, continuous fibrous glass in strand form extending unentangled, unvaryingly, and uninterruptedly along the axis of the yarn, said continuous fibrous glass in strand form having tensile strength sufiicient to withstand yarn weaving and handling stresses but being fracturable when fabric incorporating the yarn is submitted to molding pressure.

3. A non-elastic yarn for producing an extensible fabric, said yarn including a body composed of continuous fibrous glass strand material looped back and forth upon itself in overlying but progressively advancing, substantially unentangled, generally parallel courses with each course terminating in open loops, and a core combined with the body and extending uninterruptedly along the body free of entanglement with the looped fibrous glass strand material, said core comprising at least one nonlooped strand of continuous glass fibers and incorporating a sufiicient number of continuous fibers to provide tensile strength in combination with the body sufiicient to hold the yarn against weaving stresses but insufiicient to resist, without breaking, the stresses incurred subsequent to weaving in the normal utilization of the fabric.

4. A non-elastic extensible yarn including a body of continuous fibrous glass strand material looped back and forth upon itself in overlying but progressively advancing, substantially unentangled, generally parallel courses with each course terminating in open loops, and a continuous core lying longitudinally Within the body along an unvarying path, free of entanglement with the looped fibrous glass strand material and comprising at least one non-looped strand of continuous glass fibers, said core having a predetermined tensile strength sufiicient to hold the yarn from extension by normal handling tensile stresses but insufiicient to hold the yarn from extension when subjected to tensile stresses in excess of the normal handling stresses.

References Cited in the file of this patent UNITED STATES PATENTS 784,310 Draper Mar. 7, 1905 1,955,905 Christensen Apr. 24, 1934 2,017,444 Page Oct. 15, 1935 2,052,875 Gammons Sept. 1, 1936 2,387,320 Foster Oct. 23, 1945 2,719,350 Slayter et al Oct. 4, 1955 2,719,352 Slayter et al Oct. 4, 1955 2,849,785 McCullough et a1. Sept, 2, 1958 2,867,889 Thompson Jan. 13, 1959 2,928,427 Flarnand Mar. 15, 1960 2,960,117 Shimwell Nov. 15, 1960

Claims (1)

1. A NON-ELASTIC YARN FOR PRODUCING A FABRIC FOR REINFORCING MOLDED PLASTIC PRODUCTS AND WHICH IS MANUALLY NON-EXTENSIBLE BUT EXTENSIBLE UNDER THE HIGH PRESSURE OF A DIE MOLDING OPERATION, SAID YARN INCLUDING GENERALLY PARALLEL SHORT COURSES OF FORTY OR MOREFIBROUS GLASS STRANDS IN ADJACENT RELATION CROSSWISE OF THE YARN, SAID SHORT COURSES TERMINATING IN LOOPS, AND SAID COURSES PROGRESIVELY OVERLAPPING EACH OTHER LONGITUDINALLY OF THE YARN AND BEING RELATIVELY AND EASILY DISPLACEABLE UNDER A STRETCHING FORCE LONGITUDINALLY OF THE YARN, AND NON-EXTENSIBLE, NON-LOOPED CONTINUOUS FIBROUS GLASS STRANDS EXTENDING IN CLOSE ARRAY, UNENTANGLED, UNVARYINLY AND UNINTERRUPTEDLY ALONG THE AXIS OF THE YARN, SAID CONTINUOUS STRANDS HAVING INDIVIDUALLY A TENSILE STRENGTH OF AT LEAST TWO POUNDS AND THUS PROVIDING THE YARN AND THE FABRIC PRODUCED THEREFROM WITH RESISTANCE TO TENSILE FORCES TO WHICH THE YARN AND THE FABRIC MAY BE SUBMITTED BEFORE THE FABRIC IS USED AS A REINFORCEMENT FOR PLASTIC IN A DIE MOLDING OPERATION, BUT SAID CONTINUOUS STRANDS OF THE FABRIC BEING FRACTURABLE UNDER THE PRESSURE OF SUCH MOLDING OPERATION.

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