US3323302A

US3323302A - Method for producing yarn

Info

Publication number: US3323302A
Application number: US344711A
Authority: US
Inventors: Emerson B Blackstock
Original assignee: Bear Brand Hosiery Co
Current assignee: Bear Brand Hosiery Co; Paramount Textile Machinery Co
Priority date: 1964-02-13
Filing date: 1964-02-13
Publication date: 1967-06-06
Anticipated expiration: 1984-06-06
Also published as: CH445348A; SE309001B; NL6404830A; BE659749A; GB1068388A; ES299296A1; ES302682A1

Description

June 6, 1967 Filed Feb. 13, 1964 E. B. BLACKSTOCK 3,323,302

METHOD FOR PRODUCING YARN 2 Sheets-Sheet l INVENTOR.

: BY Emerson B. B/acksmck W/M% *W Afiys.

E. B. BLACKSTOCK METHQD FOR PRODUCING YARN Jung: 6, 1967 2 Sheets-Sheet 2 Filed Feb. 15, 1964 INVENTOR. Emerson B. Blacksfock Y MM 7/ Afiys.

IIAIIIIL VII/III United States Patent 3,323,302 METHOD FOR PRODUCING YARN Emerson B. Blackstoclr, Kankakee, llL, assignor to Bear Brand Hosiery (30., Chicago, Ill., a corporation of Illinois Filed Feb. 13, 1964, Ser. No. 344,711 13 Claims. (Cl. 57163) The present invention relates to improvements in methods of producing elastic or stretch-type core spun yarns, and the invention, in all of its aspects, is particularly well-adapted for use in producing composite stretch yarns wherein a sheath or covering of staple fibers is spun about a strand or core of elastic spandex or its equivalent.

Others have heretofore noted the desirability of providing elastic yarn having a sheath of staple fibers spun about a spandex or segmented elastomeric core, for it has been appreciated that such elastic yarns could be produced in deniers well below those which have been commercially feasible with the use of rubber cores, and it has also been appreciated that such yarns would be well suited for use in knitted and woven fabrics of various kinds wherein the elastic or stretch characteristic of the fabric would have many useful applications. However, the production of acceptably uniform spandex core spun yarn in commercial quantities has heretofore been very diificult and expensive to achieve because of unsolved problems in handling the spandex yarns during the spinning process.

Inasmuch as spandex core spun elastic yarn must have the sheath of staple fibers spun about the spandex while the spandex yarn is in a stretched or elastically-elongated condition, the spandex yarn must be presented to the spinning position in its stretched condition. The nature of spandex yarn has heretofore caused this operation to be too difiicult to perform uniformly or satisfactorily. Spandex yarn is supplied to the industry on pirns, wherein the spandex yarn is wrapped in multiple layers about a core. As the spandex yarn is unwound or withdrawn from the pirn, the convolutions of the spandex yarn, because of the nature of the yarn, tend to catch on each other, with the result that the yarn leaves the pirn erratically and without uniformity of tension. When the spandex yarn is pulled from the pirn, the catching and irregular release of the yarn from the pirn causes momentary increases in the yarn tension and consequent momentary and heretofore uncontrollable elastic elongations of the yarn. The result has heretofore been that the spinner has found the spandex yarn excessively stretched at one moment and almost immediately thereafter, when a convolution has broken away from the pirn, he has found the spandex yarn substantially completely untensioned. The producers of spandex yarns have sought to treat their products with lubricants and the like to avoid this problem, but their efforts, for the most part, have not been successful. The erratic and irregular behavior of spandex yarn has continued to present difiiculties for which spinners have previously had no practical or satisfactory solution. Because of the nature of spandex, tensioning devices of the type which exert friction on the yarn cannot be used, and, because of the quickly changing erratic behavior of the spandex yarn, those tensioning schemes responsive to the tension in the yarn itself also are of little or no use. The result has been that the spandex yarn has reached the spinning site in varying states of tension or elongation, and the finished yarn has accordingly been nonuniform. The nonuniform yarn has had lengths thereof wherein the spandex yarn core has been under-tensioned, and other lengths thereof wherein the spandex core yarn has been over-tensioned. Fabrics made of such yarns consequently have appeared to be "ice of a nonuniform texture and have not been commercially acceptable for many uses.

One of the principal objects of the present invention is to provide a relatively inexpensive method for spinning elastic core spun yarn wherein the aforementioned difiiculties are avoided and overcome, thereby producing a finished core spun elastic yarn that is substantially uniform throughout its length and is useful in the production of knitted and woven fabrics of all kinds, including fabrics for clothing and the like.

Another object of the present invention is to provide a method for spinning elastic core yarn on a spinning frame having drawing rolls including front rolls, and a spindle having a bobbin thereon, wherein staple fibers of any suitable kind, including cotton, wool, or synthetic staple fibers, are passed through the drawing rolls to the bobbin, and an elastomeric yarn of spandex or the equivalent is fed from a supply thereof to the bite of the front rolls and to the ribbon of staple fibers passing therethrough, the elastomeric yarn being subjected, without substantial sliding friction thereon, to a substantially constant braking force, at a position located between the supply and the front rolls, independently of the tension or speed of travel of the elastomeric yarn, the elastomeric yarn being thereby substantially uniformly elastically elongated and tensioned and being maintained in that state as it passes through the front rolls, and from the front rolls to the bobbin, during the latter of which passage the staple fibers are spun about the elastically and substantially uniformly elongated elastomeric yarn.

Still another object of the present invention is to provide a method of the character just stated, wherein the elastomeric yarn is tensioned and controlled by passing the same across a wheel located adjacent the path of travel of the elastomeric yarn to the front rolls, the wheel being driven by the elastomeric yarn and a substantially constant magnetic drag or braking force is applied to the wheel entirely independently of the degree of tension that may exist in the elastomeric yarn and substantially independently of the speed of the yarn, thereby substantially uniformly elastically elongating the elastomeric yarn before it reaches the site where the staple fibers are spun thereabout. Yet another object of the invention is to provide a method and apparatus of the character described above, wherein the elastomeric yarn is fed along a path of substantial length from the supply to the front rolls and wherein any momentary elastic elongations of the elastomeric yarn produced by irregular or erratic release of the elastomeric yarn from the supply, are caused to be distributed substantially throughout the length of the elastomeric yarn in the path, thereby minimizing and rendering substantially inconsequential the degree of momentary elongation in each longitudinal segment of the elastomeric yarn in the path and as the elastomeric yarn reaches the front rolls. Additional objects of the invention include providing a method and apparatus having the aforesaid characteristics, wherein the elastomeric yarn is withdrawn from its supply in a manner tending to minimize momentary catching of the yarn; the feeding of the elastomeric yarn and the spinning of the staple fibers thereabout are carried out so as to minimize the twist produced in the elastomeric core yarn; the spinning is carried out in a manner to avoid overheating and adversely affecting the resiliency of the elastomeric yarn as it passes through a spinning traveler; and the spun yarn is treated to reduce its liveliness without adversely affecting the resiliency or stretched condition of the elastomeric core yarn.

Other objects of the invention relate to various features of the novel method for producing elastic or stretch yarn, all of which will appear more fully hereinafter.

The nature of the invention will be understood from e following specification, taken with the accompanying "awings wherein one form of the novel apparatus, with :rtain variations, is illustrated, and upon which appaltHS the novel method may be practiced. In the drawings:

FIGURE 1 is a vertical section taken through a spin- .ng frame, illustrating in side elevation one form of the pparatus of the present invention and upon which the le method may be practiced;

FIG. 2 is a greatly enlarged fragmentary elevational iew, partially in section, showing a short length of elastic ore spun yarn of the kind which may be produced with 1e use of the present apparatus and method, the short :ngth of yarn being illustrated in its elongated or ten- .oned condition;

FIG. 3 is an enlarged cross-sectional view of the draw- 1g roll section of the apparatus shown in FIG. 1;

FIG. 4 is an enlarged schematic fragmentary top plan iew of that portion of the apparatus shown in FIG. 3, 11th most of the upper portions thereof removed to perait illustration of the passage of rovings of staple fibers herethrough when two rovings are used, the view also llustrating the position where the elastomeric core yarn s deposited with respect to the two rovings as the rovngs and the elastomeric yarn reach and pass through the ront rolls of the apparatus; and

FIG. 5 is an enlarged vertical cross-sectional view taken ubstantially along the line 55 in FIG. 1, illustrating in :ross-section a hysteresis brake assembly employed in he apparatus, a supporting bracket for the assembly being .hown by broken lines.

The apparatus shown in FIGS. 1 and 3 is a ring-type :pinning unit largely of standard and well-known con- ;truction, but modified to incorporate the novel features 3f the present invention. Only one unit of the spinning frame is shown, it being understood that a plurality of .ike units are arranged in side-by-side relationship in a :omplete spinning frame. In the single unit shown, a spandex yarn 11 or, its equivalent is withdrawn from a pirn or spool 12 thereof which is comprised, in the normal case, of a hollow tube-like core (not shown) about which the spandex or segmented elastomer has been wrapped in layers of convolutions. The pirn 12 is mounted in fixed position upon a forwardly-projecting shelf 15 that is mounted, as by a bracket 16, upon the upper end of an upstanding rod 17, the lower end of which is fixedly secured in any suitable manner upon a second shelf 18 that is fixed to a frame member 19 of the spinning frame.

Spandex, as that term is presently used in the industry, refers to a manufactured elastomeric fiber in which the fiber-forming substance is a long chain synthetic elastomer comprised of a segmented polyurethane or its equivalent. Spandex, of which there are several compositions available, is ideally suited for use in stretch-type knitted or woven goods and fabrics of various kinds, because of its ability to be stretched several times its normal length and thereafter to return substantially to that normal length. Spandex is supplied by its manufacturers in wound pirns or spools similar to the pirn 12 shown in FIG. 1, but one of the disadvantages in the use of Spandex, as previously explained, is that the strands thereof tend to cling to each other, with the result that it is difficult to withdraw the spandex from the pirn or spool at an entirely uniform rate. The highly elastic nature of spandex, together with its tendency for the fibers and convolutions to cling together, causes the spandex to tend to catch other fibers and be momentarily and irregularly stretched as it is withdrawn from the pirn. Manufacturers of spandex have experimented with the use of various coatings for their product to make it possible to withdraw the spandex from the pirn at a more uniform rate, but these efforts have not been entirely satisfactory. The spandex now available on the market continues to be difficult and troublesome to withdraw from the pirns. During the withdrawal, the fibers will periodically interfere with each other, with the result that the withdrawn fiber will be very substantially stretched at one moment, after which the fibers will suddenly become disassociated, whereupon the spandex withdrawn immediately thereafter will be substantially unstretched. One of the important advantages of the present invention, as indicated earlier hereinabove, is that this difiiculty is avoided or overcome with the use of the present invention.

It has been found that it is advantageous to withdraw spandex from its pirn from one end thereof and generally in the axial direction, rather than by unrolling the pirn by rotation about its axis. It has also been discovered that the withdrawal of spandex in a uniform manner from the pirn is facilitated if the pirn is securely fixed so as to minimize any vibrations to which the pirn may be subjected. Accordingly, in the practice of the present invention the core of the pirn 12 is preferably securely fixed to the shelf 15. For this purpose a bolt 14, having its lower end fixed in the shelf 15, may extend upwardly through the hollow core of the pirn, with the pirn held in fixed position by means of a nut 13 threaded upon the bolt 14 and with the use of a suitable washer 13a bearing upon the upper end of the core of the pirn. Care must, of course, be taken to see that the washer 13a is not of a diameter so large as to overlie the convolutions of spandex on the pirn. If desired, the lower end of the core of the pirn may rest upon a suitable pedestal (not shown) secured to the shelf 15, so as to keep the lower convolutions of the spandex on the pirn out of contact with the shelf.

In the present instance, the spandex 11 is withdrawn from the pirn 12 in an upward direction and through the eye of a relatively large pigtail 20, of brass or the like, one end of which is securely fixed in any suitable manner upon the upper end of an upstanding bracket 21 mounted upon the shelf 15 adjacent the pirn 12. The eye 22 of the pigtail is located directly above the pirn and in alignment with the axis thereof. From the eye 22 of the pigtail 20 the spandex fiber 11 extends forwardly and somewhat downwardly to a rotary hysteresis brake assembly designated generally by the numeral 23. This hysteresis brake assembly will be described more fully hereinafter. The brake assembly is mounted upon a forwardly and upwardly extending bracket 24 secured to the shelf 15, the brake assembly including a rotary wheel 25 about which the spandex fiber 11 is entrained in one complete revolution plus an approximate one-quarter revolution. From the wheel 25 the spandex fiber 11 extends downwardly through the loop of a downwardly and forward extending wire finger 26 (FIG. 3) securely mounted on a bar 27, as by a bolt 28 and a nut 29, the bar 27 being carried on a bracket 30 fixed upon a traversing bar 31. The traversing bar 31, as will be later explained, is longitudinally moved slowly back and forth during the spinning operation.

From the loop of the finger 26, the spandex fiber 11 is led into the head portion 32 (FIG. 2) of the spinning frame. This head portion includes a frame 33 (FIG. 3) carried by upstanding pedestals 34 which are fixed to a forwardly-projecting frame element 35 carried by or suitably secured to the frame member 19 of the spinning frame. The head 32 includes the usual

rear drafting rolls

36 and 37 and

intermediate rolls

38 and 39, about the latter of which is entrained a pair of rubber aprons 40 or the like which are driven :by the

rolls

38 and 39 in the direction of the arrow 41. The head 32 also includes the usual front rolls 42 and 43, together with the usual lintremoving rolls 44, 45 and 46.

In conjunction with each unit of the spinning frame one or more spools 47 of staple roving fibers are used, each spool of roving being wound upon a spindle 48 which is rotatably mounted in a vertical axial positon and seated in suitable bearings provided in the shelf 18 and the shelf 15. In FIG. 1, only one such spool of roving 47 is shown, but it will be appreciated that one, or two or more spools of roving may be employed. From the spool or spools 47 the staple roving fibers 49 are drawn forwardly and pass through a trumpet-like guide mounted upon the traversing bar 31. As shown in FIG. 4, when two spools 47 of roving are used, the trumpet-like guide 50 is provided with two bells 51 through which the roving fibers 49 are respectively passed. If only one spool 47 of roving is employed, the trumpet-like guide 50 will, of course, have only one bell 51. Similarly, if three roving spools 47 are used, the trumpet-like guide 50 will have three bells 51. From the trumpet-like guide 50, the roving fibers 49 pass forwardly between the aprons 40 and thence forwardly between the

front rollers

42 and 43.

The various rolls of the head 32, and the aprons 40, are driven in a manner well-known in the art of spinning so as to draw out and lengthen the roving fibers 49 as they pass through the head 32. In the present instance, however, the spandex fiber 11 passes downwardly through the loop of the downwardly and forwardly projecting finger 26, through a guide and into position in the substantially-direct alignment with the longitudinal center line of the roving fibers 49 as they pass into or between the front rolls 42 and 43 of the head 32. When only one spool 47 of roving is used, the spandex fiber 11 is introduced or laid into the single strand of roving 49 substantially directly in alignment with the longitudinal center line of that single strand. When two strands of roving 49 are employed, as illustrated in FIG. 4, the spandex fiber 11 is introduced directly between the two as they enter the front rolls 42 and 43. Similarly, when three rovings 49 are employed, the spandex fiber 11 is introduced substantially in alignment with the center line of the middle strand of roving 49.

The spandex fiber 11 passes through the bite of the front rolls 42 and 43 with the roving fibers, and from the front rolls 42 and 43 the roving 49 and the spandex fiber 11 pass downwardly together in the direction of the arrow 56 (FIG. 1) and extend through a spiral looped eyelet 57 mounted on a bar 58. From the eyelet 57, the spandex fiber, about which is now spun the roving fibers 49, extends downwardly to be Wound upon a bobbin 59. The bobbin 59 is mounted in the usual manner upon a spindle 60 which is journaled in a suitable bearing 61 fixed in a frame member 62. The spindle is provided with a pulley 63 and is driven by a belt 64 extending from a drive motor or other drive mechanism 65.

As the spandex fiber 11 and the rovings 49 pass to the bobbin 50, they extend through a metal clip or traveler 66 which travels around the bobbin on a ring 67 with which it has a sliding interlocking connection. The ring 67 is mounted on a rail, in the usual fashion, which is reciprocated upwardly and downwardly by well-known means to distribute the finished yarn over the bobbin in regular fashion as the spinning and winding proceeds. The bobbin 59 is rotated at high speed while the front rolls 42 and 43 are rotated at a much slower speed. The result is that the winding operation of the bobbin 50, with the trailing action of the traveler 66 causes the rovings 49 to be spun tightly about the spandex fiber 11, with the spandex fiber v11 being disposed substantially at the axial center of the spun yarn, as shown in FIG. "2, the roving fiber 49 forming a spun sheath 70 about the spandex fiber 11.

The pirn 12 is preferably placed on the shelf 15 in a position such that the unwinding of the spandex fiber 11 from the pirn takes place in a counterclockwise direction, as viewed from a position looking downwardly toward the upper end of the pirn. It will thus be appreciated that the spandex strand 11, which is normally initially wound on the pirn 12 in an untwisted condition, has a twist introduced into it as the spandex fiber is withdrawn from the stationary pirn. The preferable direction of rotation of the bobbin 59, however, is such that the spinning of the roving fibers 49 about the spandex fiber 11 is in the direction opposite this twist, so that the initial twist introduced into the spandex as it is removed from the pirn 12 is itself removed during the spinning of the yarn that takes place in the yarn between the exit rolls 42 and 43 and the bobbin 59. Because of the removal of this initial twist, and because the spandex fiber 11 is introduced to the roving fibers at substantially the longitudinal center lines of those fibers as they enter between the exit rolls 42 and 43, the sheath 70 is spun uniformly about the spandex fiber 11, and the spandex fiber 11 in the fully-spun yarn has itself insufficient twist to cause objectionable twist liveliness to the finish yarn.

After the yarn has been spun onto the bobbins 59 the yarn is preferably subjected to a controlled moistening operation for the purpose of reducing the liveliness of the yarn caused, not by the spandex fiber 11 itself, but by the spun fibers of the sheath 70 about the spandex. This moistening operation is preferably carried out in a hermeticallysealed cabinet or container. The yarn is removed from the bobbins 59 and Wound on other cores which are placed within the cabinet or chamber, and the interior of the cabinet is subjected to a vacuum-producing apparatus which produces a vacuum within the chamber or cabinet of about 28 inches of mercury. This vacuum condition is maintained in the cabinet for about seconds to remove most of the air from the yarn, whereupon steam is introduced into the interior of the cabinet from a steam line at about 20* ounds gauge pressure, When the sheath 70 of the yarn is cotton, suffi-cient steam is injected into the cabinet to raise the temperature therein to a preferred temperature less than 160 F. and preferably approximately F. This preferred temperature is maintained for a period of about four minutes, whereupon the steam is cut off and a vacuum of about 10 inches of mercury is drawn in the cabinet for approximately 30 seconds. The introduction of the steam into the cabinet introduces that and moisture to the finished yarn, thereby reducing and minimizing the liveliness of the finished yarn caused by the sheath 70 thereof, and the final vacuum applied to the interior of the cabinet serves to remove any excess moisture from the finished yarn. The maintenance of the temperature at 150 F. during this yarn treatment does not adversely affect the spandex fiber 11 in the yarn and does not substantially reduce its resilience. It will, of course, be appreciated that the temperatures referred to above be varied to suit the particular material of materials being employed in the sheath 70. It is important, however, that the temperature, in any event, be less than 212 F., inasmuch as loss of resiliency of the spandex will be experienced if that temperature is reached or exceeded for any appreciable length of time.

The hysteresis brake assembly 23, which is shown in cross-section in FIG. 5 of the drawings, includes a horizontally-disposed through-bolt 75 that is threaded or secured in any suitable fashion to the upstanding bracket 24. A generally-circular backing member 76 provided with a hub 77 is threaded onto the bolt 75 adjacent the Wheel 25, the backing member being provided with an annular lip 78 which slightly overhangs the wheel 25 to provide a recess within which the wheel turns. The wheel 25 is preferably formed of nylon or any other suitable plastic material and is provided about its periphery with diverging

flanges

79 and 80 which form a generally- V-shaped peripheral groove for receiving the strand of spandex fiber 11. If desired, the inner surface of the V- shaped groove may be in the form of alternating interlaced fingers or raised surfaces which serve to prevent the spandex fiber from slipping with respect to the wheel 25. The center portion of the wheel 25 is provided with a ball-bearing assembly 81, the inner race .of which is fixed to the through-bolt 75. The outer race of the bearing assembly is secured within an iron or steel hysteresis ring 82, and the outer periphery of that ring is fixed to the central disk portion 25a of the wheel. It will thus be understood that the Wheel 25 with the hysteresis ring 82 is adapted to turn as a unit about the axis of the throughbolt 75 on the ball-bearing assembly 81.

Opposite the central portion of the Wheel 25 a barrel member 85 of plastic or other nonmagnetic material is axially threaded upon the through-bolt 75. The inner end of the barrel is provided with a recess 86, and the opposite or outer end of the barrel is preferably provided with a recess 87. A pair of substantially-cylindrical Alnico

permanent magnets

88 and 89 are fixedly mounted in the body of the barrel 85 between the

recesses

86 and 87, with the inner ends of the Alnico magnets extending slightly into the recess 86 and to a position directly opposite and adjacent the hysteresis ring 82. The outermost ends of the Alnico magnets may be secured to a brass or other nonmagnetic plate 90 seated within the recess 87, and the plate 90 may be secured to the barrel 85 within the recess by means of a pair of screws 91, the head of only one of the screws being seen in FIG. 5. The central portion of the plate 90 has a plastic stop-nut 92 fixed thereon which is threaded upon the through-bolt 75 and provides the means by which. the barrel 85 is threaded upon the bolt 75. It will thus be appreciated that turning of the barrel 85 will cause the plastic stop-nut 92 to turn on the threads of the shaft 75 and will cause the barrel 85 and the Alnico magnets 89 and 99 therein to be adjustably advanced toward or away from the hysteresis ring 82. Any suitable arrangement may be made to limit the extent of the adjustable threaded movement of the barrel 85 toward and away from the hysteresis ring 82. For example, a cap 95 may be threaded upon the end of the through-bolt 75 within the recess 87 and held in fixed position by means of a cap-nut 96 also threaded upon the through-bolt. Fixed upon the inner surface of the cap 95 may be a stop pin 97 in position to engage a similar stop pin (not shown) fixed upon the plate 89. In this fashion the barrel 85, if desired, may be limited in its adjustable rotary movement to slightly less than one full revolution.

It will readily be appreciated by those acquainted with the hysteresis effect that, when the wheel 25 is turned so as to cause the hysteresis ring 82 to be rotated with respect to the

permanent magnets

89 and 90, magnetic flux will be generated in the ring 82 and a braking effect or magnetic drag will be produced within the ring and thus exerted on the wheel 25. Similarly, it will also be appreciated that by rotatably adjusting the barrel 85 upon the through-shaft 75, the

magnets

89 and 90 may be adjustably positioned with respect to the hysteresis ring 82, thus to adjust the amount of braking force applied to the wheel. a

One of the characteristics inherent in a hysteresis brake of the type shown and described is that the braking torque or braking force applied to the wheel 25 is substantially constant at all speeds of the wheel. As a consequence, in the present installation, and for a particular adjustment of the barrel 85 upon the through-bolt '75, a substantiallyconstant braking or tensioning force is applied by the wheel 25 upon the spandex strand II as that strand passes from the wheel 25 downwardly through the loop of the wire finger 26 and into the front rolls 42 and 43 of the spinning head 32, Without regard to the speed of the strand and independently of the tension in the strand as it reaches the wheel 25.

In the practice of the present invention for the production of yarns for use in many fabrics, the barrel 85 is preferably adjusted on the through-bolt 75 so as to cause the hysteresis ring 82 and thus the wheeel 25 to apply to the spandex strand 11 sufficient braking force as to cause the strand, after it passes from the wheel, to be elongated on the order of about 250 to 300 percent of its normal relaxed length. When 70 denier spandex is being used, for example, this braking force is preferably about 10 grams and the barrel 85 is rotatably adjusted to cause the brake assembly to provide approximately that amount of braking force. The braking force, however, may, of course, be adjusted, by adjustment of the barrel 85, to provide such elongation of the spandex fiber 11 as may be desired,

depending upon the denier of the fiber 11 being used and the amount of stretch desired in the finished yarn. The braking force selected causes the spandex fiber 11 to be substantially uniformly tensioned and stretched as it is fed downwardly through the loop of the wire finger 26 and into position between the bite of the front rolls 42 and 43. It is important that substantially this same amount of tension be maintained in the spandex fiber as it passes from the front rolls 42 and 43 to the bobbin 59 and while the roving fibers are being spun about the spandex fiber, and this maintenance of the tension is achieved, by technique well-known in the spinning art, by adjusting the rotative speed of the spindle 60 with respect to the rotative speed of the front rolls 42 and 43 and by utilizing a traveler 66 of the proper weight. In the practice of this art, however, it has been discovered that there are critical limitations in the weights of travelers that may be used, for it has been found that the use of a traveler 66 of excessive weight, while it may permit production of a finished yarn of the proper over-all size and appearance, will, in fact, cause frictional heat which adversely affects the resiliency of the spandex fiber. Indeed, it has been found that, for best results, the frictional heat generated in the spandex fiber 11, as that fiber and the roving fibers pass through the traveler 66, should not exceed about 200 F. Taking these discoveries and factors into account, applicant has found that excellent yarns of the sizes or weights indicated in the table below, may be produced at commercial rates in the manner designated by the table, while maintaining the spandex fiber 11 at its proper tension and without adversely affecting the resiliency and stretch characteristics of the spandex:

In order to produce uniform yarn in the manner described above, and in order that the spandex fiber 11 in the finished yarn will be substantially uniformly tensioned throughout the length of the finished yarn, it has also been discovered that it is very important to give particular attention to the manner in which the spandex fiber 11 is fed from the pirn 12 to the front rolls 42 and 43, and to the characteristics of the path through which the spandex fiber 11 is fed. In addition to the fact that the tensioned spandex fiber must itself not be subjected to sharp curves or to any heavy frictional dragging, and especially so between the hysteresis brake assembly 23 and the front rolls 42 and 43, it has been discovered that with the use of a braking mechanism such as the hysteresis brake assembly 23, which acts independently of the tension of the spandex fiber reaching or leaving the wheel 25, and with the use of a path for the spandex fiber 11 having a substantial over-all length of at least 30 inches from the pirn 12 to the front rolls, any momentary elastic elongations of the spandex fiber 11 produced by irregular or erratic release of the spandex from the pirn 12, are distributed substantially throughout the length of the spandex yarn 11 in that path, thereby minimizing and rendering substantially inconsequential the degree of momentary elongation in each longitudinal segment of the spandex in the path as the spandex fiber reaches and enters the bite between the front rolls 42 and 43. For this purpose, the path length should be at least 30 inches, and the optimum path length, for easy handling and high. degree of control, exclusive of that portion of the spandex fiber wrapped around the wheel 25, has been found to be from 40 to 50 inches. Somewhat longer path lengths may be used, provided the spandex fiber .11 ahead of the brake assembly 23 is properly supported without substantial friction, so as to prevent the weight of the spandex and friction from causing uncontrolled substantial elastic elongation of the fiber. In conjunction with the foregoing, and in order to minimize any momentary catching of the spandex fiber 11 on the convolutions thereof on the pirn 12 as the fiber leaves the pirn, it has also been found that the vertical distance from the top of the pirn 12 to the eye 22 of the pig-tail 20 should be at least two times the outside diameter of the pirn when the latter is full.

The elastic spun yarn produced with the use of the present apparatus and in accordance with the present method may be of any size and weight desired, and the spandex fiber 11 employed therein may likewise be of any weight or size desired and may be either multifilament or monofilament. Similarly, as previously suggested hereinabove, the staple fibers 49 employed in the manufacture of the yarn may be either natural fibers such as cotton or wool or may be any of the great number of suitable synthetic fibers, such as rayon, nylon, polyacrylonitrile staple, or polyethylene terephthalate staple, and the like, or appropriate blends of any of the foregoing. The yarn, within practical limits, may also have any degree of elasticity desired, depending upon the size and nature of the spandex fibers employed and depending upon the amount of elastic elongation of those fibers produced by the selected adjustment of the hysteresis brake as described above. I

Although only one form of the apparatus has been shown and described above, it will be appreciated that various modification of both the apparatus and the method may be made within the scope of the claims appended hereto.

,- I claim:

1. The method of producing an elastic spandex coreyarn on a yarn manufacturing frame having rolls including front rolls, and a spindle having a bobbin thereon, comprising the steps of: passing a ribbon of staple fibers through said front rolls and thence to said bobbin, withdrawing a substantially untensioned spandex elastomeric yarn from a supply thereof and feeding said spandex yarn to said front rolls and to said ribbon of staple fibers .passing through said front rolls, applying a substantially constant braking force to said spandex yarn ahead of said front rolls independently of the tension produced in said spandex yarn and independently of the speed of travel thereof and thereby producing and maintaining a substantially uniform state of elastic elongation in said spandex yarn as said spandex yarn reaches said front rolls, and driving said rolls and said bobbin to draw said staple fibers and to wrap said staple fibers about said spandex yarn as said staple fibers and said spandex yarn pass from said front rolls to said bobbin.

2. The method of producing an elastic spandex coreyarn on a yarn manufacturing frame having rolls including front rolls, and a spindle having a bobbin thereon, comprising the steps of: passing a ribbon of staple fibers through said front rolls and thence to said bobbin, withdrawing a substantially untensioned spandex elastomeric yarn from a supply thereof and feeding said spandex yarn to said front rolls and to said ribbon of staple fibers passing through said front rolls, providing a wheel and passing said spandex yarn about said wheel to drive the same as said spandex yarn passes from said supply to said front rolls, applying a substantially constant braking force to said wheel independently of the tenison of said spandex yarn and independently of the speed of rotation of said wheel and thereby stretching said spandex yarn and producing and maintaining a substantially uniform state of elastic elongation in said spandex yarn as said elastorneric yarn reaches said front rolls, driving said rolls and said bobbin to draw said staple fibers and to wrap said staple fibers about said spandex yarn as said staple fibers and said spandex yarn pass from said front rolls to said bobbin, and maintaining said state of elastic elongation in said spandex yarn while said staple fibers are being wrapped thereabout.

3. The method of producing an elastic spandex coreyar-n on a yarn manufacturing frame having rolls including front rolls, and a spindle having a bobbin thereon, comprising the steps of: passing a ribbon of staple fibers through said front rolls and thence to said bobbin, withdrawing a substantially untensioned spandex elastomeric yarn from a supply thereof and feeding said spandex yarn to said front rolls and to said ribbon of staple fibers passing through said front rolls, providing a wheel and passing said spandex yarn about said wheel to drive the same as said spandex yarn passes from said supply to said front rolls, applying a substantially constant magnetic drag to said wheel and thereby stretching said spandex yarn and producing and maintaining a substantially uniform state of elastic elongation in said spandex yarn as said spandex yarn reaches said front rolls, driving said rolls and said bobbin to draw said staple fibers and to wrap said staple fibers about said spandex yarn as said staple fibers and said spandex yarn pass from said front roll to said bobbin, and maintaining said state of elastic elongation in said spandex yarn while said staple fibers are being wrapped thereabout.

4. The method of producing an elastic spandex coreyarn on a yarn manufacturing frame having rolls including front rolls, and a spindle having a bobbin thereon, comprising the steps of: passing a ribbon of staple fibers through said front rolls and thence to said bobbin, withdrawing a substantially untensioned spandex elastomeric yarn from a supply thereof and feeding said spandex yarn along a path of substantial length to said front rolls and to said ribbon of staple fibers passing through said front rolls and causing any momentary elastic elongations of said spandex yarn produced by irregular release of said spandex yarn from said supply to be distributed substantially throughout the length of said spandex yarn in said path, thereby to minimize and render substantially inconsequential the degree of any said momentary elongations in each longitudinal segment of said spandex yarn in said path, applying a su-bsantially constant braking force to said spandex yarn at a position in said path ahead of said front rolls and independently of the tension of said spandex yarn and independently of the speed of travel thereof, thereby producing and maintaining a substantially uniform state of elastic elongation of said spandex yarn as said spandex yarn reaches said front rolls, and driving said rolls and said bobbin to draw said staple fibers and to wrap said staple fibers about said spandex yarn as said staple fibers and said spandex yarn pass from said front rolls to said bobbin.

5. The method of producing an elastic spandex core yarn on a yarn manufacturing frame having rolls including front rolls, and a spindle having a bobbin thereon, comprising the steps of: passing a ribbon of staple fibers through said front rolls and thence to said bobbin, withdrawing a substantial-1y untensioned spandex elastomeric yarn from a supply thereof and feeding said spandex yarn along a path of substantial length to said front rolls and to said ribbon of staple fibers passing through said front rolls and causing any momentary elastic elongations of said spandex yarn produced by irregular release of said spandex yarn from said supply to be distributed substantially throughout the length of said spandex yarn in said path, thereby to minimize and render substantially inconsequential the degree of any said momentary elongations in each longitudinal segment of said spandex yarn in said path, providing a wheel adjacent said path and passing said spandex yarn about said Wheel to drive the same as said spandex yarn passes along said path from said supply to said front rolls, applying a substantially constant magnetic drag to said wheel and thereby stretching said spandex yarn and producing and maintaining a substantially uniform state of elastic elongation in said spandex yarn as said spandex yarn reaches said front rolls, driving said rolls and said bobbin to draw said staple fibers and to wrap said staple fibers about said spandex yarn as said staple fibers and said spandex yarn pass from said front rolls to said bobbin, and maintaining said state of elastic elongation in said spandex yarn while said staple fibers are being wrapped thereabout.

6. The method of producing an elastic spandex coreyarn on a yarn manufacturing frame having rolls including front rolls, and a spindle having a bobbin thereon, comprising the steps of: passing a ribbon of staple fibers through said front rolls and thence to said bobbin, withdrawing substantially untensioned spandex elastomeric yarn from a supply thereof and feeding said spandex yarn along a path at least thirty inches in length to said front rolls and to said ribbon of staple fibers passing through said front rolls and causing momentary elastic elongations of said spandex yarn produced by irregular release of said spandex yarn from said supply to be distributed substantially throughout the length of said spandex yarn in said path, thereby to minimize and render substantially inconsequential the degree of any said momentary elongations in each longitudinal segment of said spandex yarn in said path, providing a wheel adjacent said path and passing said spandex yarn about said wheel to drive the same as said spandex yarn passes along said path from said supply to said front rolls, applying a substantially constant magnetic drag to said wheel and thereby stretching said spandex yarn and producing and maintaining a substantially uniform state of elastic elongation in said spandex yarn :as said spandex yarn reaches said front rolls, driving said rolls and said bobbin todraw said staple fibers and to wrap said staple fibers about said spandex yarn as said staple fibers and said spandex yarn paSS from said front rolls to said bobbin, and maintaining said state of elastic elongation in said spandex yarn while said staple fibers are being wrapped thereabout.

7. The method of producing an elastic spandex core spun yarn on a spinning frame having drawing rolls including front rolls, a spindle having a bobbin thereon, and a ring and traveler, comprising the steps of: passing a ribbon of staple fibers through said drawing rolls and through said traveler to said bobbin, feeding a spandex yarn from a supply thereof to said front rolls and to said ribbon of staple fibers passing through said front rolls, applying a substantially constant braking force to said spandex yarn ahead of said front rolls independently of the tension of said spandex yarn and independently of the speed of travel thereof and thereby producing and maintaining a substantially uniform state of elastic elongation of said spandex yarn as said spandex yarn reaches said front rolls, driving said rolls and said bobbin to draw said staple fibers and to spin said staple fibers about said spandex as said staple fibers and said spandex yarn pass from said front rolls and through said traveler to said bobbin, and controlling the speed of said front rolls and said bobbin to maintain the heat of friction below 200 F. in said spandex yarn as said spandex yarn and said staple fibers pass through said traveler.

8. The method of producing an elastic spandex core spun yarn on a spinning frame having drawing rolls including front rolls, a spindle having a bobbin thereon, and a ring and traveler, comprising the steps of: passing a ribbon of staple fibers through said drawing rolls and through said traveler to said bobbin, feeding a spandex yarn from a supply thereof to said front rolls and to said ribbon of staple fibers passing through said front rolls, applying a substantially constant braking force to said spandex yarn ahead of said front rolls independently of the tension of said spandex yarn and independently of the speed of travel thereof and thereby producing and maintaining a substantially uniform state of elastic elongation of said spandex yarn as said spandex yarn reaches said front rolls, driving said rolls and said bobbin to draw said staple fibers and to spin said staple fibers about said spandex as said staple fibers and said spandex yarn pass from said front rolls and through said traveler to said bobbin, and controlling the speed of said front rolls and said bobbin to maintain the heat of friction in said spandex yarn below the temperature at which the elasticity of said spandex yarn is decreased as said spandex yarn and said staple fibers pass through said traveler.

9. The method of producing an elastic spandex coreyarn on a spinning frame having drawing rolls including front rolls, and a spindle having a bobbin thereon, comprising the steps of: passing a ribbon of staple fibers through said drawing rolls and thence to said bobbin, withdrawing a spandex elastomeric yarn in a substantially untensioned condition from a stationary spool thereof in a direction generally axially of the spool and thereby twisting said spandex yarn in a first direction, feeding said spandex yarn from said supply thereof to said front rolls and to said ribbon of staple fibers passing through said front rolls, applying a substantially constant braking force to said spandex yarn ahead of said front rolls independently of the tension of said spandex yarn and independently of the speed of travel thereof and thereby producing and maintaining a substantially uniform state of elastic elongation in said spandex yarn as said spandex yarn reaches said front rolls, driving said rolls and said bobbin to spin said staple fibers about said spandex yarn in a direction opposite said first direction as said staple fibers and said spandex yarn pass from said front rolls to said bobbin, and maintaining said state of elastic elongation in said spandex yarn while said staple fibers are being spun thereabout.

10. The method of producing an elastic spandex coreyarn on a spinning frame having drawing rolls including front rolls, a spindle having a bobbin thereon, and a ring and traveler, comprising the steps of: passing a ribbon of staple fibers through said drawing rolls and through said traveler to said bobbin, withdrawing a spandex elastomeric yarn in a substantially untensioned condition from a stationary spool thereof in a direction generally axially of the spool and thereby twisting said spandex yarn in a first direction, feeding said withdrawn spandex yarn from said supply along a path of substantial length to said front rolls and to said ribbon of staple fibers passing therethrough and causing any momentary elastic elongations of said spandex yarn produced by irregular release of said spandex yarn from said supply to be distributed substantially throughout the length of said spandex yarn in said path, thereby to minimize and render substantially inconsequential the degree of any said momentary elongations in each longitudinal segment of said spandex yarn in said path, providing a wheel adjacent said path and passing said spandex yarn about said wheel to drive the same as said spandex yarn passes along said path from said supply to said front rolls, applying a substantially constant magnetic drag to said wheel and thereby stretching said spandex yarn and producing and maintaining a substantially uniform state of elastic elongation in said spandex yarn as said spandex yarn reaches said front rolls, driving said rolls and said bobbin to spin said staple fibers about said spandex yarn in a direction opposite said first direction as said staple fibers and said spandex yarn pass from said front rolls to said bobbin, and maintaining said state of elastic elongation in said spandex yarn while said staple fibers are being spun thereabout.

11. The method of producing an elastic spandex core spun yarn on a spinning frame having drawing rolls including front rolls, a spindle having a bobbin thereon, and a ring and traveler, comprising the steps of: passing a ribbon of staple fibers through said drawing rolls and through said traveler to said bobbin, withdrawing a spandex yarn from a stationary spool thereof in a direction generally axially of the spool and thereby twisting said spandex yarn in a first direction, directing said withdrawn spandex yarn from said supply along a path at least thirty inches in length to said front rolls and causing momentary elastic elongations of said spandex yarn produced by irregular release of said spandex yarn from said spool to be distributed substantially throughout the length of said spandex yarn in said path, thereby to minimize and render substantially inconsequential the degree of and said momentary elongations in each longitudinal segment of said spandex yarn in said path, providing a wheel adjacent said path and passing said spandex yarn around at least a portion of the periphery of said Wheel to drive the same as said spandex yarn passes along said path from said spool to said front rolls, applying a substantially constant magnetic drag to said wheel and thereby stretching said spandex yarn and producing and maintaining a substantially uniform state of elastic elongation in said spandex yarn as said spandex yarn reaches and enters between said front rolls, driving said rolls and said bobbin to spin said staple fibers about said spandex yarn in a direction opposite said first direction as said staple fibers and said spandex yarn pass from said front rolls and through said traveler to said bobbin, maintaining said state of elastic elongation in said spandex yarn while said staple fibers are spun thereabout, maintaining the heat of friction in said spandex yarn below the temperature at which the elasticity of said spandex yarn is adversely affected as said spandex yarn and said staple fibers pass through said traveler, and finally reducing the wildness of the spun yarn by subjecting said spun yarn to moisture and heat at a temperature below the temperature at which the elasticity of said spandex yarn is adversely afi'ected.

12. The method of producing an elastic spandex coreyarn on a yarn manufacturing frame having a pair of rolls, a spindle having a bobbin thereon, and a ring and traveler, comprising the steps of: passing -a ribbon of staple fibers through said rolls and through said traveler to said bobbin, Withdrawing a substantially untensioned spandex yarn from a supply thereof and feeding said spandex yarn to said rolls and to said ribbon of staple fibers passing through said rolls, applying a substantially constant braking force to said spandex yarn ahead of said rolls independently of the tension of said spandex yarn and independently of the speed of travel thereof and thereby producing and maintaining a substantially uniform state of elastic elongation of said spandex yarn as said spandex yarn reaches said rolls, driving said rolls and said bobbin to Wrap said staple fibers about said spandex yarn as said staple fibers and said spandex yarn pass from said rolls and through said traveler to said bobbin, and controlling the speed of said rolls and said bobbin to maintain the heat of friction in said spandex yarn below the temperature at Which the elasticity of said spandex yarn is decreased as said spandex yarn and said staple fibers pass through said traveler.

13. The method of producing an elastic spandex core spun yarn on a yarn manufacturing frame having a pair of driven rolls, a spindle having a bobbin thereon, and a ring and traveler, comprising the steps of: passing a ribbon of staple fibers through said driven rolls and through said traveler to said bobbin, withdrawing a spandex yarn from a stationary spool thereof in a direction generally axially of the spool and thereby twisting said spandex yarn in a first direction, directing said withdrawn spandex yarn from said supply along a path of substantial length to said driven rolls and causing momentary elastic elongations of said spandex yarn produced by irregular release of said spandex yarn from said spool to be distributed substantially throughout the length of said spandex yarn in said path, thereby to minimize and render substantially inconsequential the degree of any said momentary elongations in each longitudinal segment of said spandex yarn in said path, providing a wheel adjacent said path -and passing said spandex yarn around at least a portion of the periphery of said wheel to drive the same as said spandex yarn passes along said path from said spool to said driven rolls, applying a substantially constant magnetic drag to said wheel and thereby stretching said spandex yarn and producing and maintaining a substantially uniform state of elastic elongation in said spandex yarn as said spandex yarn reaches and enters between said driven rolls, driving said rolls and said bobbin to wrap said staple fibers about said spandex yarn in a direction opposite said first direction as said staple fibers and said spandex yarn pass from said rolls and through said traveler to said bobbin, maintaining said state of elastic elongation in said spandex yarn while said staple fibers are wrapped thereabout, and maintaining the heat of friction in said spandex yarn below the temperature at which the elasticity of said spandex yarn is adversely affected as said spandex yarn and said staple fibers pass through said traveler.

References Cited UNITED STATES PATENTS 2,036,778 4/1936 Schenck 5712 2,076,271 4/1937 Harris 5712 X 2,210,884 8/1940 Chittenden et al. 57163 2,293,748 8/ 1942 Johnson 188-104 2,519,882 8/1950 Bullard et al. 2,724,065 11/1955 Saxl 226195 X 2,768,796 10/1956 Levine 242- 2,895,286 7/1959 OConnell 57156 3,022,565 2/1962 Fitzgerald 2872 3,092,953 6/1963 Blackstock 57-12 X 3,115,745 12/1963 Lathem et al. 57163 FOREIGN PATENTS 908,112 10/ 1962 Great Britain.

FRANK I. COHEN, Primary Examiner.

STANLEY H. GILREATH, MERVIN STEIN,

Examiners.

D. E. WATKINS, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,323,302 June 6, 1967 Emerson B. Blackstock It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below Column 13, line 7, for "and" read any Signed and sealed this 2nd day of January 1968.

(SEAL) Attest:

EDWARD J. BRENNER Edward M. Fletcher, Ir.

Commissioner of Patents Attesting Officer

Claims

1. THE METHOD OF PRODUCING AN ELASTIC SPANDEX COREYARN ON A YARN MANUFACTURING FRAME HAVING ROLLS INCLUDING FRONT ROLLS, AND A SPINDLE HAVING A BOBBIN THEREON, COMPRISING THE STEPS OF: PASSING A RIBBON OF STAPLE FIBERS THROUGH SAID FRONT ROLLS AND THENCE TO SAID BOBBIN, WITHDRAWING A SUBSTANTIALLY UNTENSION SPANDEX ELASTOMERIC YARN FROM A SUPPLY THEREOF AND FEEDING SAID SPANDEX YARN TO SAID FRONT ROLLS AND TO SAID RIBBON OF STAPLE FIBERS PASSING THROUGH SAID FRONT ROLLS, APPLYING A SUBSTANTIALLY CONSTANT BRAKING FORCE TO SAID SPANDEX YARN AHEAD OF SAID FRONT ROLLS INDEPENDENTLY OF THE TENSION PRODUCED IN SAID SPANDEX YARN AND INDEPENDENTLY OF THE SPEED OF TRAVEL THEREOF AND THEREBY PRODUCING AND MAINTAINING A SUBSTANTIALLY UNIFORM STATE OF ELASTIC ELONGATION OF SAID SPANDEX YARN AS SAID SPANDEX YARN REACHES SAID FRONT ROLLS, AND DRIVING SAID ROLLS AND SAID BOBBIN TO DRAW SAID STAPLE FIBERS AND TO WRAP SAID STAPLE FIBERS ABOUT SAID SPANDEX YARN AS SAID STAPLE FIBERS AND SAID SPANDEX YARN PASS FROM SAID FRONT ROLLS TO SAID BOBBIN.