US2811013A - Yarn twisting machine - Google Patents

Description

Oct. 29, 1957 IN 2,811,013

YARN TWISTING MACHINE Filed Sept. 1, 1951 4 Sheets-Sheet 1 INVENTOR. NORMAN E. KLEIN Oct. 29, 1957 N. E. KLEIN YARN TWiSTING MACHINE INVENTOR. NORMAN E. KLEIN wwffiw 4 Sheets-Sheet 2' Filed Sept. 1, 1951 177 TOR/V67 Oct. 29, 1957 N. E. KLEIN 2,811,013

YARN TWISTING MACHINE Filed Sept. 1, 1951 4 Sheets-Sheet 5 INVEN TOR.

NORMAN E.KLE|N BY 4/% 5M Oct. 29, 1957 N. E. KLEIN 2,811,013

YARN TWISTING MACHINE Filed Sept. 1, 1951 4 Sheets-Sheet 4 BYWJAKM/ United tates Patent i YARN TWISTIN G MACHINE Norman E. Klein, Pendleton, S. C., assignor to Deering Milliken Research Corporation, near Pcnzlleton, S. (3., a corporation of Delaware Application September 1, 1951, Serial No. 244,812

14 Claims. (Cl. 57--58.86)

This invention relates to yarn twisting devices for use in the textile industry and, in particular, to twisting machines of the type which impart two twists in the yarn for each revolution of the twister spindle.

Heretofore, many attempts have been made to employ the two-for-one twisting principle as a means of increasing the rate of yarn production. In some instances, the gain in twisting rate was substantially offset by the required reduction in spindle speed in order to maintain the resulting balloon diameter within reasonable confines, as dictated by the gauge of existing standardcommercial upright'twisting frames. I have discovered, as set forth in my copending application, Serial Number 133,047, filed December 15, 1949, now Patent No. 2,731,786, that the two-for-one principle can be employed to provide a twisting spindle that is compact in size and which will operate on standard commercial upright frames at substantially higher speeds than heretofore practiced with conventional one-for-one spindles, thereby increasing the rate of yarn production from two to four times that of the conventional spindles. While the twister described in my aforesaid application is a marked improvement over prior art devices, I have discovered that simplification of structure together with other improvements have made it possible to materially extend the usefulness of the device to a wider variety and weights of yarn.

It is, therefore, an object of my invention to provide a yarn twisting spindle of the two-for-one type that is operative on standard commercial upright twisting frames and capable of imparting a high twist at higher spindle speeds to a wider variety andweights of yarns than has heretofore been achieved.

A further object of my invention is to provide such improvements in the over-all yarn tension control in twisters of the aforesaid type, that a more uniform high twist can be imparted to a wider variety and weights of yarns than has been produced on devices of the prior art. Briefly, the device of my invention whereby the above objects are achieved consists of an arrangement for supporting a yarn supply package in concentric relationship with a rotatable spindle that carries a conventional whorl beneath the supply package, but is provided with an improved flyer and yarn storage device. Yarn to be twisted is drawn upwardly off the package, fed downwardly through a primary tension control array supported above the package, then radially out through the spindle in contact with the yarn storage device and flyer and finally upwardly to a suitable windup reel or bobbin.

In the past, considerable difficulty has been experienced in twisting zero twist and low pre-twist yarn of the synthetic continuous filament types due to the formation of snarls in the yarn as it is withdrawn from the supply package.

between the yarn package and the primary yarn tension ing array. Just enough tension is provided to prevent the free unwinding of yarn. The pretensioning-device I have overcome this difliculty by the pro-. vision of a simple yarn pretensioning device positioned- 2,811,013 Patented Oct. 29, 1957 also prevents relative creep of individual fibers of the twist yarn.

. A further feature of my invention resides in improvements in the primary tension array which is so constructed to automatically respond to variations in input tension as may arise from variations in yarn diameter, non-uniform sizing treatment or drag in withdrawal from thesupply package, so as to maintain the output tension more nearly constant. The improved primary tension array also makes provision for easy and rapid adjustment of tension'and, above all, is so constructed to accommodate substantially all continuous filament synthetic yarns known in the textile industry at the present time. The

improved tension array is also effective to properly regulate tension of yarns of a wide range of denier or weight.

Another feature of my invention which has materially aided in making the two-for-one twister a universal machine with respect to its yarn handling ability resides in an improved yarn storage arrangement associated with the flyer. I have discovered that the control of the balloon diameter in upright twisters of the type here under consideration is dependent upon the selection of the proper ratio of flyer to yarn storage device diameter and this'ratio, in general, must increase with an increase in yarn denier or weight. In order to provide a proper regulation of tension to maintain a constant balloon diam eter for different weight yarns as well as yarns differing in basic constituency, the wrap around surface of the yarn storage device is given a spiral configuration in part only. Such surface provides, with the required limits, anincreasing moment arm for feeding energy into the balloon with increases in wrap around thereby causing the yarn storage device to properly stabilize the yarn balloon for different yarns. Y

My invention also contemplatesthe provision of a simplified arrangement for magnetically stabilizing the yarn supply support platform. This arrangement also automatically functions to apply a braking force to stop rotation of the platform in the event of inadvertent rotation thereof.-

Other objects and advantages of the invention, as well as details of construction of the preferred embodiment thereof, will become apparent from the following description when 'read in connection with the accompanying drawings in which:

Figure 1 is a vertical sectional view partly in elevation of a two-for-one twister embodying the invention;

'Figure 2 is a plan view of the pretensioning device forming part of the twister of the instant invention;

Figure 3 is an enlarged vertical sectional view of the primary tensioning array of the twister shown in Figure 1;

Figure 4 is an elevation view partially in section of the tension array viewed at right angles from that shown in Figure 3;

Figure 5 is a schematic view of the primary tensioning device of Figures 3 and 4, illustrating the principle of operation; 7

Figure 6 is an enlarged cross-sectional view taken along the line VI-VI of Figure 1, showing further details of the twister flyer and yarn storage device;

Figure 7 is a fragmentary top plane view of the twister, principally showing the combined magnetic stabilizer and brake; and

Figure 8 is a sectional view of the magnetic stabilizer and brake assembly, as viewed along line VIIIVIII of Figure 7.

In Figure 1 of the drawings, the reference numeral 10 designates a portion of a conventional twister frame havgate 14, of conventional design. The swing gate 14 supports a bolster 16 resiliently clamped to an extension 21 of the swing gate by a nut. 18 bearing against a spring 20 disposed about the bolster. Further resilience is maintained by the use of a felt washer 22 and a felt sleeve 24 disposed as shown.

The bolster 16 carries an upstanding rod 26' about;

which a whorl 28 is journaled and adapted for rotation on antifriction bearings, such as ball. beatings; 30.. The

upper end of the whorl 28 has an upstanding: tubularextension 32 which terminates in a tapered portion to receive a ball bearing 34. The ball bearing. 34 is arranged to support a cup-shaped yarn supply package. support 36. The yarn. supply package; support 36. has a; COIlCEHr; tric upstanding tubular central-portion 38- terminating in.

. ed portion at the upper end of the sleeve 42.v It will thus be seen that as the. pedestal 44 is. screwed downwardl'y the ball bearing 34 will be firmly clamped be tween the annular ledge. 40 and the lower end of the pedestal; Rubber rings 46 are disposed on either side of the ball, bearing 34 so as. to. provide absorption of vibrations as may be caused by high speed. rotation of the whorl 28 and the parts carried thereby.

The-yarn supply 48 is held within the cup-shaped package support 36 and preferably is wound on a bobbin 49 having an upper flange 51 and a circular handle 53 of the. form shown in my copending application, Serial Number 249,547 filed October 3,. 1951, now Patent No. 2,756,006.

The bobbin 4'9 with yarn supply 48 and the pedestal 44' are enclosed by a plastic, transparent cover member 50 which is. provided with a tapered circumferential flange at its lower end to frictionally engage a complementary flange on the upper end of the package support 36.

Disposed within the cover member 50 is a yarn pretensioning device consisting of a ring 52 provided with a plurality of inwardly extending bristles 54. The ring 52 is preferably positioned at a level intermediate the flange 51 of the bobbin 49 and the rim of the circular handle 53-. The individual bristles may be. formed of nylon or other suitable plastic material and are preferably cemented to the ring 52 and disposed at anangle of approximately 45 with reference to their respective tangent to the ring, as more clearly shown in Figure 2. The purpose and operation of the ring and bristles will be more fullydescribed hereinafter.

The ring 52 may be secured to the inner wall of the. cover member 50 in any suitable manner, such as the means. 56, including a plurality of at least three detents formed integrally with the. cover member. The ring 52 is placed in position by forcing it beyond the detents and, thereafter, is frictionally held in the desired position.

The tubular pedestal 44 has a conical yarn guide cap 58 provided with a. centrally disposed yarn passage 60. Immediately below the cap 58 and arranged within the pedestal 44 is a primary yarn tensioning array generally designated at 62. The primary tensioning array comend to a relatively small radius andarranged to bear prises coacting stationary and movable elements between i which the yarn is adapted to be drawn and because of the particular arrangement of these elements, as will be presently described, the tension array may be said to be of the gate type. The stationary elements in this; in-

stance may be in, the form of a plurality of rods or pins constructed of. case-hardened steel or ceramic material and set transversely across the bore of the tubular pedestal 44 slightly disposed to one side of the diametrical center; The rods 64 are preferably evenly spaced in the axial direction of the pedestal 44 and held in po sition by frictional engagement with suitable openings extending through the walls of the pedestal. The movable elements of the tensioning array comprise a plurality of spaced transversely extending bars 66 of generally rectangular cross section. The bars 66 may be formed of case-hardened steel or of a ceramic material. In either instance, the edges of the bars 66 facing the pins 64 are given an arcuate configuration slightly con cave so as to assist in centering the yarn as it is drawn between the stationary and movable elements. The movable elements 66 are arranged in spaced relationship adjacent one end of a movable arm 68. The spacing of the bars 66 is such that they will freely interleave or interdigitate with the rods 64 but without producing physical contact therewith. Any suitable means may be employed to secure the bars 66 to the arm 68 such as by welding or clamping in the event that steel is employed or as by cement in the event that the bars 66 are constructed of a ceramic material.v While the stationary and movable elements 64 and 66 have been illustrated respectively as pins and. bars, it. is, obvious that a large variety of equivalent structures. could be substituted provided such structures present a plurality of smooth hard yarn. engaging surfaces about which yarn may be caused to: wrap when the respective elements are brought into operative relation.

The lowerend of arm; 68. has. a bifurcated construc tion, each leg of which terminates in a knife edge 70, as. more clearly shown'in: Figures 3, and 4.: A circular plug 72 makes a sliding fit with the lower end of the pedestal 44: and is provided with two rather shallow V'- shaped grooves disposed in diametric alignment across the upper face of the. plug, one on each side of a central opening 76 provided for the downward passage of yarn. It will. thus be seen that. arm 68'- carrying the tensioning bars, 66 may be. rocked about the knife edges to a limited amount sons to move the bars 66 toward and away from the, stationary rods. 64. Proper alignment of the. bars 66. with respect toth'erods 64 is. obtained by adjusting the position of plug 72 within the. tubular pedestel 44.. .When the proper alignment has} been made, the

plug 72 may be fixed in position by means of set screws 78 screw-threaded through the side wall of the pedestal.

The arm. 63 has. an aperture St) provided therethrough intermediate its ends for thereception of the tongued nd. 82 of a leaf spring 8.4 bowed, as, shown, so as. to be. capable. of exerting aforcein a direction generally longitudinall'y thereof whenstressed. The upper end, of the spring 84 has. an offset: portion 86 rounded at: its, free on the surface of, aninternal annular re-entrantgroove provided at 38 in. ailtnurledrcollar 90. The collar 90 is screw-threaded, as shown, about the pedestal 44 to provide an adjustment. of the. tension of the spring. An opening 92 extending longitudinally of the pedestal 44 accommodates the spring 84 inthe position shown-and also'provides. access to the movable elements of the tension array. A. handle 94 extending, from the upper end of the arm68 projects outwardly and may be grasped by the. operatorso as to rock the arm 6.8 outwardly to an open position when it is desired to thread the device prior to starting a twisting operation.

*The upper end of arm 68 is also provided with a curved, portion extending. substantially at right angles to the main portion of the arm and to which is secured a. tension plate-96. Coacting with the tension plate 96 is 21 Similar plate 98 resiliently and slidably mounted for movement in a horizontal direction. This particular mounting is ac complished by the provision of two cars 100. formed, intea v w th the pla e e ch having. n ap rt re ther a through for the passage of support. rods. 102.. The. sup port rods 102 have horizontal portions. along which the plate QS may slide and are provided with. an upturned portion anchored in; the cap 58. The movable. plate 9.8

is'resiliently biased lightly toward the plate 96 by means of a leaf spring 104, the lower end of which is secured.

to the inner wall of the pedestal 44 by a screw 106.

The plug 72 also supports a thread guide 108 which extends upwardly therefrom in alignment with the central opening 76. A complete description of the operation of the yarn tensioning device 62 will be given later in connection with the over-all operation of the twister.

The upper end of the whorl 28 has a sleeve extension 110 to which is secured a flanged flyer hub 112. Secured to the flange of the flyer hub 112, as by riveting, is a flyer 114 having a shallow, generally cup-like shape and constructed of metal, plastic or other suitable material. The lower portion of the flyer hub 112 is provided with a continuous groove portion 116 spiral-like in part which serves as a yarn storage device, the operation of which will be more fully described hereinafter.

The tubular extension 32 has an arcuate slot 118 cut therein adjacent its lower end so as to provide a passage to a thread guide tube 120 disposed within the extension. The lower end of the thread guide tube 120 has a ceramic bead insert 122 thereon to serve as a wearing surface for the yarn passing therethrough. A diamond-shaped open ing 124 in the sleeve 110, disposed in alignment with the slot 118, provides means for bringing the yarn out of the spindle. The yarn emerging from the opening 124 is directed through a notch 126 provided in the yarn storage device 116. As indicated more clearly in Figure 6, the yarn storage device 116 has a surface at 128 in the form of a groove extending in either direction from the notch 126,'increasing in radius in spiral-like manner through about 120 and then merging with a surface at 130 having a constant radius. The surface 130, however, is disposed at a higher level, as more clearly shown in Figure 1. The stepped surfaces 128 and 130 are slightly tapered inwardly from the bottom to the top to facilitate yarn movement upwardly from the lower to the higher step. It is, thus, seen that the yarn storage arrangement provides a stepped wrap-around surface in the form of a sheave which gradually increases in radius from a lower to a higher step. The yarn end emerging from the yarn storage device is directed upwardly in contact with the flyer 114 through a fixed guide 132 to a suitable take-up package or bobbin.

In the event of yarn breakage outside the spindle, the tail end issuing from the opening 124, unless it is restrained in some manner, will continue to feed outwardly due to the centrifugal force acting thereon occasioned by a high spindle speed. Obviously, the continued feeding of yarn through the spindle when an end is broken will cause lint to become entangled with the spindle or even interfere with the operation of adjacent spindles on the same frame. This problem of yarn feed through is solved by the provision of means for severing the yarn adjacent the spindle opening. Disposed within the sleeve 110 is a split ring 131 of spring sheet steel or the like which may be fastened to the sleeve by'rivets as shown in Figure l. The split in the ring 131 is aligned with the diamond shaped opening 124 so as not to interfere with the normal passage of yarn therethrough but coacts with one or the other of the V-shaped sides of the opening to cause the yarn tail to be severed adjacent the spindle opening. The free end of the yarn within the spindle is also held between the ring 131 and the sleeve 110 so that the yarn will no longer feed through the opening 124. For a further disclosure of this particular feature referencev may be had to my copending application, Serial Number 179,069, filed August 12, 1950, now Patent No. 2,625,786, wherein the feature is specifically described and claimed.

The yarn supply package support 36 is held against rotation during the operation of the twister by means of a adjacent the yarn supply package support 36. A slotted magnet support member 138 is mounted for limited rock-" ing movement on the end of bracket 136 by means of a pin 140, as shown. I

A U-shaped permanent magnet 142, preferably of high permeability, is clamped to the lower end of the support member 138 by means of a clamping plate 144 and screws 146, only one of which is shown. The yarn package support 36 has a cold rolled steel insert148 inserted in the vertical wall thereof in general horizontal alignment with the open ends of the magnet 142 when the magnet support memebr 138 is in the position as shown in Figure 8. In this position, the magnetic attraction of the magnet 142 for the steel insert 148' maintains the yarn supply support 36 in fixed position, thereby overcoming the tendency of the support to rotate. The upper portion of the support member 138 has an arcuate surface 150 which is groovedto-receive a strip: of resilient material, such as rubber tubing,'to serve as a brake surface. The tubing 152 may be retained in position by means of a wire 154 threaded therethrough and passing about .the transverse leg portion of member as shown.

.The combined mass of the magnet support member 138 andthe magnet 142 is so arranged with respect to the axis of rotation about the pin 140 that, when the attraction between the magnet and the steel insert 148 is removed, the member 138 will rotate about. pin 140 in counterclockwise direction, as viewed in Figure 8.

. It will, thus, be seen that in the event that the magnetic attraction between the magnet 142 and the steel insert 1 148 is not sufficient to hold the support 36 against inadvertent rotation the magnet support 138 will rotate in'a counterclockwise direction bringing the brake surface. 152

into contact with the side of the support 36 to arrest rotation thereof.

A chain 156 may be employed to connect the upper end of the magnet support 138 with an appropriate portion 158 of the twister frame by means of suitable fastening means 160 and 162, as indicated. The length of chain 156 is so selected that it will permit suflicient angular movement of the magnet support 138 to engage and stop the yarn supply support 36 in the event of rotation thereof, but becomes taut when the swing gate14is moved from an operative to an inoperative position. The

chain 156 thereby causes the rocking magnet support 138 l to be rotated in a clockwise direction to the upright position, as shown in Figure 8 making it ready automatically to again perform its magnetic stabilizing position. The

yarn supply support 36 may then be rotated until the steel insert 148 is again adjacent to the open end of the magnet 142. The magnetic attraction between the magnet and the steel insert is sufficient to maintain the magnet,

support 138 in the upright position so that the spindle may be returned to the operative position by movement of the swing gate 14 until the whorl 28 is in contact with the conventional driving belt.

In order to prevent broken ends or lint developed at any one spindle position from interfering with an "ad-.. jacent spindle position on the twister frame, Ih'ave' pro-.1 vided an arcuate-shaped shield 164- which may be 'supported frorn'the edge of the arm 134 and held in'position by a plurality of screws 166. The shield 164 is spaced a sufficient distance from the yarn supply support 36 to prevent contact with the yarn balloon.

The specific function of the several components of th device of my invention during a twisting operation will now be described. In threading up the spindle, the swing gate 14 is swung into the inoperative position so that to replace an empty yarn bobbin with wound on the bobbin 49.

"7 Theyarn end from the package 48 is. twisted about one. end' of a: long semi-flexible threading tool, commonly referred to. as av snake. and rocking the arm 68 in a counterclockwise direction, a sufficient. separation of the tension. plates 96; and 98 and. also the movable. tension bars 66 fromthe fixed pins 64 may be obtained. to. allow passage of the snake there.-

between. The snake is then passed downwardly through.

gate. 1,4 to operative position so that. the whorl 28 is rotated at high, speed as a. result ofiengaging the conventional belt drive. As. the twisting operation begins, th yarn end is: secured to the take-up. bobbin in the usual manner.

The flyer- 114 and: itshnb. 112 rotating with the whorl causes the; yarn to. be drawn into the notch 126 and driven in a spiral path about the support 36 and the plastic cover 50;, the. generatrix of the yarn or balloon taking the general shape of the. support and cover but without engaging the outer surfaces thereof. For each revolu tionof. the flyer 114, two twists are imparted to the Y rn.

The imparting of a high twist at high linear yarn speeds for a variety of kinds and. weights of yarn brings into play the cooperative action of all yarn tensioning devicesherein provided. For example, in the twisting of low initial twist continuous filament acetate yarnof 75 denier, there is a tendency for the yarn to unwind too freely from thepackage 48 and produce snarls as it enters the passage 60 above the primary tensioning array 62'. There is also a tendency for the individual fibers of the. yarn, particularly of a zero twist type of yarn, to creep with respect to each other, thereby causing snarls to form. This snarling is avoided by the use of the pretensioning bristles 54. The bristle support ring 52 is so positioned in the cover 50- that the bristles extend inwardly and circumferentially in the general direction of rotation of the yarn as it is drawn off the supply package. As the. yarn is drawn oh, the bristles 54 cause it to be deflected slightly so that it makes contact with the upper bobbin flange 51 and circular handle 53 thereby increasing the drag. This arrangement provides a measure of tension regulation in that the higher the package pull-oft tension, the higher the bristles will be lifted. As the bristles are lifted the pinch and wrap around actions decrease, to lessen the tension contributed by the bristle array. The approach angle of yarn, with respect to the bristles, is a relatively small acute angle so that very little tension is imparted, being only sufficient to prevent the free unwinding of yarn and the relative creep of the individual fibers. In practice, I have found that nylon bristles having a diameter in the neighborhood of .005 inch, positioned at approximately a 45 angle with respect to the corresponding tangent to the ring, provides the necessary control for yarn deniers in the range of 50 to 150.

.The primary tension array 62 is largely responsible for maintaining a constant tension through the device, in spite of variations in input tension. For example, if the input tension is low, the spring 84, acting on the movable arm 68, causes the movable bars 66 to push bites of yarn between the stationary pins 64, thereby increasing the amount of yarn wraparound about the tensioning elements to equalize the output tension. As the input tension increases, the pull on the yarn passing through the tensioning array 62 increases, tending to straighten By grasping the; handle 94.

. '8 the. yam Pa h y.-moying, the arm .ti reaain t i .tloiorcci f p i Mina. count r lockw se. itec ionasviewed to Figure 3 and, consequently, decreasing thermal-amount ofyarnwrap around to lessenlthe tensions. Inordcri'to p qv at he Pr per regul t o f.. theprimary: tensioncontrol, 'i have. discovered that the applied fomeofithe; spring 84 acting to rotate the arm 68 decrease as; the tensioning. elements 6.6 and 64 areforqediitr thddirection of senar i m The r gement most; successful to accomplish the. desired result embodies the,- toggle. principle, as more clearly illu trated in Figure. 5a.. In the; illustration of Figure. 5. corresponding; parts, as; shown in. Figures 1, 3. and 4-, are, given prime numeral. identificm tion.

The; force. exerted by spring. 84' may be; considered. as.

being substantially constant for all operative positions. of. the movable tension arm. 6,83. In; the full line. position f h rm h mom nt of. force, tending to cause rotation of the arm, is, represented s: Er. At this'par-.. ticular posit-ion it will be noted that r: is relatively small. Howevenin the broken. line; position of the arm 68" or a positionof gr r tension. requirements, the. moment of. force. tending; t rotate the arm is Fr. In the. latter case, r' is. materially larger than t. Asthe. arm 68 is swung; clock-wise from-the, solid line position, .r' approacheszero. as. the toggle. approaches its dead center position. Thus, it; can'be. seen. that, as a requirement f l c rrective. tension ensues;- the. toggle. arrange-. ment' ofthe spring .84 and arm. 68 provide the correct conditions;

The efficiency of. the primary tension array is materially enhanced by; the; reduction of frictional loss. at all pivot points. Knife-edge bearing surfaces are provided at 7-0 where the, arm 68 pivots in the V-shaped .grooves 74 and" the. lower end of spring 84 presses against a knife-edge.

end. 86 of the swing 84' makes substantially: a point con tactwith the; annular channel 88. Adjustment of the tension or the. primary tension array is also greatlysimplified in that. it is accomplished by rotating the knurled collar 96 in'the required direction to. increase or decrease the; tension of the. spring 84.

The primary tension array 62 is provided with an auxiliary tension device in the form of the plates 96 and 98. Inasmuch as these plates precede the: pins 64 and bars 66 in point of yarn travel, the plates may be properly termed pretension means. Their principal function, however, is to always maintain a certain minimum tension in the twister spindle, even though the tension by wrap around at the pins 64 is substantially reduced. This is accomplished by the follow-up movement given to the plate 98 slidingly suspended from the horizontal rods 102. As plate 96 moves to the left, even to a point where little or no wrap around tension is created at the pins 64 and bars 66, the spring 104 will maintain the plates 96 and 98 in tension with respect to the yarn. It will also be observed that the tension between the plates 96 and 93 decreases as the arm 68 is rotated in a counterclockwise direction as viewed in Figure 3. The decrease, however, is at a much slower rate in that the toggle action of the arm 68 and spring 84 is not directly involved. 7

Further yarntensioning and control is desirable and is provided in the form of the yarn storage device 116 formed on the lower portion, of the fiyer hub 112. The yarn storage device has as its principal function the cooperation with the primary tension array in the control of the size and shape of the yarn balloon. In operation, the yarn end emerging firom the. orifice 124 does not move directly radially outwardly to the periphery of the flyer 114 but makes a bend at the. notch 126 into the yarn storage device 116 and, wraps itself aroundthe yarn storage surface over a predetermined angular distance. For a particular whorl-dyer geometry this angular wrap is dependent upon the'yarn material, density, spindle speed, primary tension control setting and degree of twist being f 9 imparted. The twist shows its effect through density change of the yarn which in turn effects the air drag to centrifugal force ratios establishing the particular balloon shape. The air friction or drag in this instance causes the lagging behind or wrap around effect of the yarn. The angular distance or degree of wrap around determines the relative amount of tension'being provided by the yarn storage device. r i

That the yarn storage device assistsin maintaining the proper balloon geometry will be evident from a consideration of the following operational conditions. Assuming that for a certain settingiof primary tension control the input tension or drag on the ,yarn suddenly increases and is not completely compensated for by the primary tension control, the take-up speed'being constant, there will result anincrease in the overall tension, thus causing the balloon to contract. The contracting balloon ofiers less air friction and causes the yarn in the balloon to speed up thereby decreasing the amount of wrap around on the yarn storage surface. Decreasing the amount of wrap around also decreases the tension, thus allowing the balloon to regain its normal size and configuration.

. If the input tension should decrease without beingproperly regulated by the primary tension control, the yarn balloon will tend to increase in size thereby causing more drag and a resultantincrease in wrap around about the yarn storage device. The increase in wrap around is accompanied by acorresponding increase in tension, which again tends to bring the balloon dimensions down to the required size. .Thus, the'yarn storage device acts as a regulator, feeding the required amount of yarn into the balloon to maintain its geometry substantially constant.

In order to enable the yarn storage device to properly regulate the balloon dimensions for a wide variety of kinds and weights f yarns, approximately the first 120 of wrap around surface of the yarn storage device is disposed in the form of a spiral so that operation may be selected in the range that best fits the control requirements of the particular yarn. This need is evident from the fact that as yarn denier is increased the centrifugal force value increases more rapidly than the air drag factor. A smaller wrap around step, providing less lever arm coupling and drive, coordinates with the relatively smaller power requirement to overcome the relatively smaller air drag.

The over-all effect of theseveral tensioning control means embodied in my invention has made it possible to regulate the yarn balloon to such a-degree that no external devices, such as wire rings or circular bands, are needed to limit the balloon diameter. I The use of such confining rings orbands is a direct limitation in that certain yarns, such as thermoplastic types, will not withstand the abrading action of contact with the confining means.

The twister embodying the aforedescribed features of my invention is particularly suited for handling yarn composed of synthetic fibers, such as rayon, polyamides, polyesters and polyacrylic yarns, While yarns such as silk and spun glass fiber have not been twisted on the spindle disclosed herein, 'it is believed that such operation would be entirely satisfactory.

--It-has been established that synthetic yarns of weight from lp' denier to 300 denier can be successfully. handled. The number of turns per inch does not appear to be critical, the upper limit being dictated by the strength of the yarn. As a further illustration of typical performance, a particular spindle having a 1 /3 pounds yarn capacity and set on 5 inches gage positions will handle yarns of weight from 50 denier to 150 denier at a spindle speed of about 15,500 R. P. M. Beyond this three-to-one denier range, the speed of the spindle must be varied to some degree inversely in respect to yarn size to maintain optimum balloon shape.

While I have shown and described a specific embodiment of my invention, it is to be understood that the same is for the purpose of illustration and that changes and modifications may be made by those skilled in the art 10 without departing'from the ed claims. a

The followingis claimed:

1. In a two-for-one twister in which yarn travels from a yarn package to ayarn guide at the top of a normally non-rotatable tubular pedestal, then passes through the bore .ofsaid pedestal, in which'regiou a first twist is imparted to the yarn, down to a rotating flyer, thence out through a radial passage in said flyer, up around the flyer and bobbin in substantially balloon-like manner, through a second yarn guide, a second twist being imparted to the yarnbetween said flyer and said second yarn guide, and finally. to yarn'take-up means, theimprovement which comprises flexible pretensioning means located between the top of saidpackage and the first-mentioned yarn guide to prevent kinking of the yarn in that region, primary tensioning means disposed within the pedestal for inducing tension regulation in' the yarn at that region;

and secondary tensioning means associated with said flyer for assisting'in controlling the extent of ballooning of the yarn vas itpasses from the flyer to said second yarn guide.

2. In a two-for-one twister for yarn, having a support member, .a flyer rotatably mounted on said support member, a yarn package support cup supported by said flyer androtatable'relative thereto, a yarn package having a handle portion thereon, a tubular pedestal centrally disposed within said cup and upstanding therefrom, said pedestal fitting within the bore of said yarn package,

means for rotating said flyer and means preventing therotation ofthe said cup and pedestal; the improvement which comprises flexible pretensioning means for biasing theyarn against the handle portion of said yarn package as it passes from said yarn package to the pedestal, primary tensioning means disposed within said pedestal for regulating tension in the yarn as it passes through said pedestal, and secondary tensioning means associated with.

said flyer for regulating tension in the yarn while in engagement with:the flyer, whereby said twister is adapted for use witha wide variety of v types and weights of yarn.

3. In a twister for imparting two turns to a strand of yarn per each revolution of a flyer, including normally non-rotatable yarn package support means; a flyer rotata ble relative to said support means and means for rotating said flyer; the combination with pretensioning means and secondary tensioning means of agate tensioning device comprising a plurality of pins fixed inspaced parallel relationship within said support means, a plurality of correspondingly spaced bars movable into inter-digital rela-' tionship with said fixed pins, the strand passing between said fixed pins and movable bars, and means urging saidmovable bars into interdigital relationship with said fixed pins, said last-mentioned means being so arranged that the urging force varies directly with the extent of the in- 1 terdigitation of said pins. 1i

said bars substantially occupy the space between said pins, and a toggle spring biasing said arm from said first position to said second position, the force of said spring increasing as said arm approaches said second position.

5. The device as in claim 4 wherein said movable arm is provided with a bifurcated portion adjacent the pivot axis, said portion terminating in a knife edge, and an annular member is mounted in said pedestal, said member being provided with a diametric V-shaped groove in which said knife edge rocks.

6. The device as in claim 4 wherein a collar is carried threadwise by said pedestal; a re-entrant groove being provided internally of said collar, one end of said toggle spirit and scope of the append T1 itting engaging: said groove, the; other end! being remov v ably attached to approximately the midpoint of said arm; whereby the projected line of said, springaapproaches the pivota axis of said; arm as said; arm moves. to said first positiomthereby to reduce the. efliective leverage. on said am. and. re edes from, said. axis. as. said arm moves to said second position, thereby increasing the effective everage on saidarm; r

Ehe device.v as. in claim 6 whereintlrefirst-mentioned nd engages said; groove with substantially point contact and said. otherend bears. against a. knife edge provided ntermediate the ends, of said arm, whereby the. friction be w n. the moving parts of said device is reduced to. a minimum.

8. In a two-for-one. twister including normally stationary bobbin support means consisting of a cup for the reception of a bobbin having top and bottom flanges, and an upstanding pedestal centrally disposed within said cup and fitting within the bore of said bobbin; improved pretensioning means comprising a multiplicity of flexible membersarrayed intermediate the top flange of said bobbin and, the top of said pedestal to. bias, to a variable extent, depending. upon the. tension in the yarn, the yarn front it normal path of travel between said bobbin and said pedestal to prevent snarling and kinking thereof.

9-,. In a; two-for-one twister including a normally stai nary' bobbin support platform, an. upstanding pedestal carriedby said support platform, said pedestal being adapted t extend through the. bore of a bobbin and to. receive at, its upper extremity a yarn end. from said bob.- bin, and a covercarried by said support platform; improved pretensioning means comprising an annular inwardly extending member positioned within said cover nd carried thereby, said annular inwardly extending member being adapted; to. bias a yarn end from its normal Path oi travel between a bobbin on said support platform and; the upper extremity of said pedestal.

10. An improved pretensioning means as in claim 9 wherein said inwardly extending member comprises a circular array of flexible bristles secured to the said cover,

said bristles, extending inwardly of said cover at an angle; less than the normal thereto on a horizontal plane hrough.- aid cover.

Ina; two-for-one twisting apparatus in which an end; of yarn, travels under tension in balloon fashion from an orifice. ina rotating spindle to an apex guide positioned substantially on the. extended axis ofrotation of S id: Spind e, improved means for controlling the tension in the yarn balloon comprising'in combination a wrap. aronndthread storagev device carried by said spindle to rece v the yarn from said orifice and to. guide the same into. said yarnbal-loon, said yarn storage device having a yarn engaging surface to. frictionally engage said yarn and additionally tension the same a variable amount depending npon'the. degree to. which said yarn wraps around; stora e device,'-various segments of said surballoon; is driven with an efiective lever arm of increasing length as the degree of yarn wraparound on said,

2,81 note threadstorage device increases, and a readily and precisely; adjustable .tensioning means to engage said yarn prior to "its contact with said thread storage device so that. the-tension in the yarn passing to said thread storage devicecan beadjustedto give a mean degree of wraparound on said thread storage device to provide an effective lever arm of substantially the optimum length fordriving a yarn balloon of any desired one of various typesand deniers of yarns.

12. The combination of claim 11 wherein said tensioning means comprises a yarn tension regulator to reduce the magnitude of tension fluctuations in the yarn passing to. said thread storage device.

' 13.. The combination of claim 12 wherein said tension I regulator'- is a gate-type regulator positioned within a stayarnpackage support member carried of said storage device with increasing degrees of yarn wrap-around on said storage device so that said yarn balloon is driven with an effective lever arm of increasing length as the degree of wrap-around on said storage device increases, a continuously variable yarn tensioning means to adjustably tension an end of yarn passing to said thread storage device, and readily accessible manipulative I means for varying the tension imparted to said yarn by said tensioning means, whereby the tension in the yarn passing to said thread storage device can be adjusted to give a mean degree of wraparound on said thread storage device which provides an elfective lever arm of near optimum length for driving a yarn balloon of any desired one of various types and dealers of yarns.

References Cited in the file of this patent UNITED STATES PATENTS 384,890 Chapman June 19, 1888 1,064,292 Crawford June 10, 1913 1,403,454 Skedgell Jan. 10, 1922 1,776,638 Parks Sept. 23, 1930 1,800,784 Durand Apr. 14, 1931 2,222,847 Kent Nov. 26, 1940 2,445,721 Bartholomew July 20, 1948 2,478,926 Kingsbury Aug. 16, 1949 2,478,927 Carter Aug; 16, 1949 2,479,826 Prick et al. Aug. 23, 1949 2,534,496 Agresti Dec. 19, 1950 2,556,290 Nelson June 12, 1951 2,578,513 Cochran Dec. 11, 1951 2,590,372 Bley Mar. 25 1952 2,597,015 May May 20, 1952 2,625,786 Klein Jan. 20, 1953 2,662,364 Kingsbury Dec. 15, 1953 FOREIGN PATENTS 449,879 Ital-y July 4, 1949 571,112 Germany Feb. 23, 193-3

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