US2777276A - Method and apparatus for false twisting yarn - Google Patents

Description

Jan. 15, 1957 N. E. KLEZN METHOD AND APPARATUS FOR FALSE TWISTING YARN Filed May 11, 1953 1 ball- INVENTOR flrmzvZf/fl9akg 1/45; @4, yaw ww ATTORNEYS United States Patent Ofitice 2,777,276 Patented Jan. .15, 1957 Norman E. Klein, Pendleton, S. C., assignor to Deering Milliken Research Corporation, Pendleton, S. C., a corporation of Delaware Application May 11, 1953, Serial No. 353,950

6 Claims. (Cl. 57-773) This invention relates to the processing of filamentary textile materials and is more particularly directed to an improved method and apparatus for false twisting strands of textile material, having particular utility in the production of crimped effects therein.

It has been known for a considerable period of time in the textile art that crimped effects could be imparted to textile strands by twisting such strands to a high degree of twist, setting the twist therein, and thereafter untwisting the strand. It has been also suggested byprior patents that the steps of twisting and untwisting in the above process could be practiced simultaneously by means of a false twister. At the time it was made, this latter suggestion was viewed with considerable interest by the workers in this art since it apparently presented va means by which the separate and costly steps of supertwisting and untwisting could be dispensed with. However, in so far as I am aware, the possibilities which the improved method possessed, at least from a theoretical aspect, have not been realized when the method was adapted for commercial production. Apparently, this has been due to the fact that in the false twisters heretofore known in the, art, the means by which the yarn was frictionally engaged in order to obtain the purchase or grip thereon necessary for rotating it about its axis were so constructed that the yarn just approaching the frictional engaging means laterally abutted or contacted the yarn just leaving such means with the result that portions of the yarn rubbed against each other, causing broken filaments, stripped-back filaments, and other similar defects, none of which can be tolerated in any number in a piece of finished fabric. The arrangement which was adopted almost without exception by the prior art to obtain the necessary purchase on the yarn consisted essentially of a cylindrical pin or a grooved pulley mounted for rotation about a transverse axis, one convolution of the yarn being wrapped around the pin or pulley. Thus, the laterally adjacent portions of the convolution rubbed against each other as the yarn was drawn around the pin or pulley, damaging the yarn in the manner just described.

The primary object of the present invention is therefore to provide a method and means for false twisting yarn in which the portions of the yarn passing through the twister are maintained in non-contacting relationship.

A further object of this invention is to provide an improved method and means of falsetwisting yarn in which the yarn engaging means is so disposed that the portion of the yarn just approaching said means does not contact the portion of the yarn just leaving said means.

Other and further objects and advantages will be ap' parent from the following detailed description when read Figure 3 is a fragmentary elevation of a modified form of the improved twister and Figure 4 is a view essentially diagrammatic, for the preferred arrangement for practicing the method of the present invention.

The apparatus which itself forms a part of the present invention and with'which the method of the present invention is practiced is illustrated in Figures 1 and 2. In these figures the'numeral ll designates a tubular stator member having a threaded lower portion 13. At the end of the stator member 11 remote from the threaded portion 13 is a section of enlarged diameter or crosssection 15 in which there is formed a socket or recess 17. Press fitted into the recess 17 is the outer race 19 of an oil-sealed anti-friction bearing, generally designated 21 of the type capable of withstanding high speed rotation of the order of 20,000 to 40,000 R. P. M. Supported by the inner race 23 of the anti-friction bearing 21 is a tubular rotor member 25 having at its lower end a portion of reduced cross section 27 which is press fitted into inner race 23. The tubular rotor member 25 is preferably mounted in co-axial relationship with the tubular stator member 11 with the bores extending through the respective lengths of the tube member being in substantial registration.

There is formed in the distal or upper end of the rotor member 25 a pair of diametrically opposite slots 29 and 29', extending from the upper face of the rotor member 25 into the body of the same for a portion of its length. Supported by the portion of the walls of the rotor 25 on either side of the pair of slots 29 and 29' is a cylindrical cross-member or pin 31, the ends of which fit into suitable apertures provided in the rotor walls, being secured therein in any desired manner. As can be seen from Figures 1 and 2, the cross member 31 extends substantially diametrically across the rotor member 25, traversing the bore thereof, being preferably at right angles to the plane of the slots 29 and 29' with its longitudinal axis slightly inclined or obliquely disposed with respect to the longitudinal axis, i. e., the axis of rotation, of the rotor member 25. Preferably, the portions of the cross-member 31 on either side of the rotor axis are tapered in the direction of such axis so as to provide a central necked down portion 33 on the cross-member 31 which is adapted to have a single convolution of yarn wrapped therearound. The function of the necked down portion 33 is to center the yarn on cross-member 31 and in connection with the accompanying drawings in which 1 reduce the ballooning action of the yarn while it is being rotated at high speed.

The manner in which my improved false twister is threaded up for actual operation may be described as follows: One end of a strand of filamentary textile material of relatively great length is attached to the end of a flexible snake in a fashion well known in the art. The snake is then inserted into the lower end of the bore of stator member 11 and drawn vertically up through both of members 11 and 25, the yarn being drawn with it and eventually passing completely through the device, lying on one side or the other of cross-member 31. The snake is then moved over to one side of the twister, so that the yarn lies around the top of cross-member 31, and inserted into one of the slots, say, 29, passed horizontally underneath cross-member 31 and out through the other slot, 29. Following this, the yarn can be removed from the snake and attached to any suitable col lection means. At this point the yarn extends axially through the twister, having one convolution wrapped around the pin 31. The collection means may now be actuated and rotation imparted to the rotor member 25 in any desired manner, and as the yarn is drawn through the device, twist is inserted therein on the input side of 3 cross-member 31 and removed therefrom on the output side of cross-member 31.

In Figure 3 there is shown a modified form of the improved false twister in which a cross-member 31' is formed in the shape of an inverted L, the long leg of the L being inserted in a vertical recess 35 provided in the upper face of a rotor with the short leg extending across the bore of the rotor. slightly inclined from the horizontal similar to member 31 in Figures 1 and 2 and is also necked down, as at 33', the termination thereof being preferably of enlarged bulbous shape to confine the yarn thereon. The modified version operates in substantially the same fashion as does the first described form with the exception that it is easier to thread up since the yarn need not be insorted through the rotor slot but can merely be wrapped around the member 31.

The essence of my improved false twister by which it differs from the false twisters heretofore known in the art resides in the inclination of cross-member 31 with respect to the axis of rotation of stator 25, which is, of course, also the axis of rotation of cross-member 31, since the cross-member forms a part of rotor 25; ticular angle at which the pin is disposed may be varied considerably without departing. from the invention. In general, it is not necessary to resort to the use of excessively large angles and I have had good success using an angle of from about'5 to about 15 degrees, substantially as illustrated in Figure l.

The inclination of the pin accomplishes the rseult of urging the laterally adjacent portions of the yarn convolution apart in the following manner: Since the tension in the input portion of the yarn convolution, that is, the portion just approaching the pin, acts in an essentially downwardly direction, this portion tends to move toward the lower end of the pin and, correspondingly, since the tension in the output portion of the convolution The short leg is, of course The paracts essentially upwardly, this portion tends to move toward the upper end of the pin. Thus, the normally adjacent portions of the convolution tend to be maintained apart and there is little or no opportunity for them to rub against each other. In accordance with this theory, it is highly desirable to so carry out the threading up of the false twister that the input side of the convolution is on the lower side of the pin while the output side of the convolution is on the upper side of the pin.

The method of the present invention, in its broadest aspects, contemplates the feeding of a strand of filamentary textile material to a longitudinal member rotating about a substantially transverse axis which may be either co-axial with or parallel to the path of the yarn, the member having its longitudinal axis inclined or obliquely disposed with respect to such axis of rotation, wrapping at least one convolution of the strand around the longitudinal member and withdrawing the strand from the longitudinal member. However, since this phase of my invention has been found to have particular utility as a part of a method for crimping yarn and since this method is representative of the successful practice thereof, this latter phase will be described and illustrated in connection therewith although, as will be readily appreciated, it is by no means limited thereto inasmuch as it is capable of application to widely varying end uses.

In Figure 4, the numreal 41 designates a yarn supply package, such as a pirn, bobbin, cake or the like, from which a single strand of yarn is unwound and passed through a disc tension device 43 of the type well known in the art. From the tension device 43, the yarn travels upwardly past one side of a polished chromium plated heater element 45 connected by electrical leads 47 and 47' to a suitable source of alternating electric current, thence through the false twister unit 48, the details of which have already been described, and finally to a take-up package, generally designated 49, which may conveniently take the form of a metal-flanged bobbin driven by a rotating cork-covered roll 53. The twister unit 48 may be supported in any desired fashion but I have found it expedient to associate the false twister unit with the conventional spindle bolster of an Atwood M-lOO up-twister. 55 indicates such a bolster, having a vertical aperture therethrough penetrated by the tubular stator member 11 of the false twister unit. The lower face of the enlarged portion 15 rests against the upper face of the bolster and the portion of the body of the stator 11' disposed below the bolster is encircled by a compression spring 57, which beans at its upper end against the lower face of bolster 55 and at its lower end against a nut 59 threaded on the lower portion 13' of stator 11.

The function of heater element 45 is, of course, to soften the yarn so that as it is later twisted by the false wister unit 43 it sets or hardens in its twisted configuration. in broader terms, its purpose is to place the yarn in such a state or condition that it may be later set in a given configuration. While, in most instances, an electric heater strip is the simplest and cheapest means of accomplishing this function, obviously, other means could be employed if desired. For example, a steam chamber could be utilized, the yarn passing through such chamber before its delivery to the false twister unit or,

alternatively, the yarn could be impregnated with one of a number of well known resinous setting agents, such as urea formaldehyde, melamine formaldehyde, or the like. Again, compounds for producing swelling resistance could be applied to the yarn, as is disclosed in Patent 2,463,618. Broadly, therefore, the presentinvention embraces any and all treatments by which yarn may be caused to retain a particular configuration. The particular conditions at which the various treatments should be carried out are well within the skill of the art and willnot be described in detail.

By the proper selection of the means for treating the yarn as just described, yarns of widely varying character and composition may be processed in accordance with my invention. Where the yarn is heated prior to its passage through the false twister unit by means of an electric heater or a steam chamber, I have found the best results are obtained with yarns which are thermo plastic it. character, including linear polyamides, derivatives of cellulose, polyesters of ethylene glycol and terephthalic acid, polymers consisting in whole or in part of acrylonitrile, and polyvinyl resins and copolymers of the same. On the other hand, where the use of chemical treatments are contemplated, my method may be applied with equal facility to natural and regenerated cellulosic fibres as well as those based on proteinaceous materials.

In .theusual case I prefer that the yarns which are to be processed in accordance with my improved method should be of the continuous filamentary type, that is, the individual filaments which are grouped together to comprise the yarn are substantially continuous in their length. However, under certain circumstances my invention may be modified or used with staple fibre yarns. This can be accomplished, for example, where two or more staple fibre yarns are processed together, i. e., either in side-by-side relationship or in the form of a plied yarn. The desired result may also be achieved provided the staple fibre yarn is initially twisted to a point where the discrete fibres are substantially cohesive and provided further that the twist inserted by the false twisting unit is in the direction of the twist initially in the yarn so that the yarn never passes through a point of zero twist.

From the above, it will be apparent to those skilled in the art that I have provided an improved method and means by which false twist may be continuously inserted and removed in a moving strand of yarn without rendering the yarn defective by reason of broken filaments, strippedback filaments and the like.

The foregoing description of specific embodiments of the related aspects of my invention is set forth by way of example only, and it is in no way intended that the invention is limited to the specific features thereof but only by the spirit and scope of the claims hereunto appended.

Having thus described my invention, that which is claimed is:

1. A false twister spindle comprising a tubular stator member, a tubular rotor member rotatably carried by said stator member in coaxial relationship therewith, and a pin diametrically mounted in'said rotor member, said pin having its axis inclined with respect to the common axis of said stator and rotor members, and said pin having a center portion of reduced diameter.

2. A false twister spindle comprising a tubular stator member, a socket of enlarged section at one end of said member, an anti-friction bearing having an inner and outer race, the outer race being received by said socket, a tubular rotor member coaxial with said stator member, a portion of reduced cross-section at one end thereof, said portion engaging said inner race, and a cross-member diametrically mounted in said rotor member, having its longitudinal axis obliquely disposed with respect to the axis of said rotor member, the center portion of said cross-member being of reduced cross-section.

3. In a method of false twisting yarn, the improvement which comprises forming and maintaining a single loop in a substantially straight length of a moving strand of said yarn, retaining adjacent sections of yarn in said loop out of contact by positioning said loop in a plane which is at an angle to said straight length such that the tension in the strand entering and departingsaid loop tends to open the same, and rotating said loop about the longitudinal axis of said straight length.

4. A false twist spindle comprising a rotatable cylindrical member having an axial bore adapted to receive a moving strand of filamentary textile material, said cylindrical member having a pair of longitudinally extending diametrically opposed slots, said slots, in each instance, being open ended at one end of said cylindrical member, a cross-member, with a center portion of reduced diameter, extending across said bore, said cross-member having its longitudinal axis inclined with respect to the axis of said bore and said cross-member having opposite ends supported by the opposed sections of said cylindrical member between said slots, whereby a threading tool can be passed through said slots inwardly of said cross-member subsequent to being passed through said axial bore to result in a yarn end being looped around said crossmember.

5. A false twister spindle comprising a rotatable cylindrical member having an axial bore therein adapted to receive a moving strand of filamentary textile material and an elongated yarn engaging element carried by said member, said elongated element having a first section extending longitudinally of said cylindrical member from one end thereof and said elongated element having a second section extending from said first section substantially across the extended axis of rotation of said rotatable member with the longitudinal axis of said second section inclined with respect to the axis of said bore, said second section having an unsupported end and a center portion of reduced diameter, whereby a loop in a strand, passed through the axial bore in said rotatable member, can readily be passed over the free end of said yarn engaging element and is thereafter retained in position by said portion of reduced diameter.

6. A false twister spindle comprising a rotatable member having an axial bore therein to receive a moving strand of filamentary material, a cross-member carried by said rotatable member, said cross-member having its longitudinal axis inclined with respect to the axis of said bore, and loop positioning means to retain a loop, formed in said moving strand of material and placed about said cross-member, in such a position that said loop lies generally in a plane which is at an oblique angle to the axis of rotation of said rotatable member, whereby the tension in the yarn entering and departing said loop retains adjacent portions of the yarn in said loop out of contact with each other.

References Cited in the file of this patent UNITED STATES PATENTS 633,964 McMichael Sept. 26, 1899 1,728,414 Jowett et al. Sept. 17, 1929 1,772,109 Quaas Aug. 5, 1930 1,830,728 Wiese Nov. 3, 1931 1,847,582 Wenzel Mar. 1, 1932

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