US2210884A - Method of making elastic yarn - Google Patents

Description

Aug 13g 1940 F. DfcHrrTENDEN r-:r A1. 2,210,884

METHOD OF MAKING ELASTIC YARN BY l A'rroRNEYs Aug.13,194o. FgD. CHITTENDEN UAL 2,210,884 Y METHOD oF MAKING ELAsTIc YARN Filed Fei. 11, 1959 2 sheets-sheet 2 VIV/A Patented Aug. 13, 1946 UNITED vSTATES PATENT OFFICEy Rupprecht,

Barrington,

R.. I., assignors to United States Rubber Company, New York, N. Y., a corporation of New Jersey Application February 11, 1939, Serial No. 255,912

8 Claims.

This invention relates to improvements in the method of and apparatus for making a balanced .elastic yarn consisting of a twisted rubber core having a single cover of textile fibers spun about the core in a direction to cause the helical windings of the cover to balance the twists of the rubber core,

In making such an elastic yarn it is necessary first to twist the bare rubber core, after which the cover is spun thereupon in the opposite direction. Approximately fty per cent of the twist imparted to the bare rubber core is or may be removed as the cover and core are spun together to wind the cover about the core. Therefore it is necessary to impart a relatively high number of twists per inch to the rubber core preparatory to spinning the cover thereupon, and the cost of pretwisting this rubber core unless performed at high speed and under the most favorable conditions may constitute a substantial part of the cost of producing such elastic yarn.

The elastic yarn above described and one method of making the same is fully disclosed and claimed in the Boutwell H. Foster Patent No. 2,024,156 granted December 17, 1935. But in this, Foster patent the bare rubber core is described as having been previously twisted and wound onto' a spool from which it is supplied to the mechanism for spinning a cover thereupon.

One important feature of the present invention resides in the method of an apparatus for -pre twisting the bare rubber core and then spinning the cover thereupon vall in a continuous operation.

In order that the nished elastic yarn herein contemplated may be well balanced and uniform in construction and stretch characteristics it is important to avoid the occurrence of variations in the stretch of the rubber core at certain stages during the formation of the elastic yarn. This is particularly true with respect to the operation of pretwisting the rubber core, because variations in the stretch of the rubber core at this time will change greatly the number of twists per inch imparted thereto.

Another important feature of the invention therefore resides in feed means for drawing the rubber thread endwise from the rotating let-off package at a definite speed to thereby impart tol this thread a predetermined number of twists per inch for a given percentage of stretch, and a further feature resides'in the construction whereby the operation of this feed means at a definite speed ratio to the nip rolls of the spinning mechanisms to which the rubber thread is delivered serves accurately to control the tension of this thread at the instant it is being delivered to the thread, which is rotated as the thread is drawnv endwise therefrom to twist the thread, may be supported in various positions as the thread is drawn therefrom. For example it is contemf plated that the thread may be drawn downwardfrom the package in the direction of gravity, or:

upwardly therefrom against the force of gravity, or at angles to these positions.

One of the more speciiic features of the invention therefore resides in the arrangement whereby the rubber thread travels in a general downward direction from the time it leaves-the rotating supply package until the cover is spun thereupon and the yarn is wound on the take-up package. 4 l

Other features of the invention and novel combination of parts in addition to the above will be hereinafter described in connection with the accompanying drawings which illustrate good practical forms of the invention.

In the drawings:

Fig. 1 is a conventional diagrammatic view with parts in section of one form of mechanism for carrying out the invention;

Fig. 2 is an enlarged side view of an elastic yarn formed upon the apparatus of Fig. 1 and comprising an elastic core and a cover wound helically thereupon;

Fig. 3 is a top view of the motor brake mechanism of Fig. 1;

Fig, 4 is a view similar to Fig. 1 showing a modific-ation thereof; and

Fig. 5 is a similar view showing a further modiiication of Fig. 1. The present invention was developed primarily for the manufacture of fine elastic yarns having a core as fine as 75s or finer, although the invention may be employed to manufacture elastic` yarns having a larger core. A large number of twists per inch must therefore be imparted to this ne rubber thread before the cover is spun thereupon, and the number of twists may be as high as 200 per inch or higher. It is therefore important that the mechanism provided to impart this twist to the ne vrubber thread shall operate at high speed in order to give a reasonably high production of elastic yarn per covering unit 'I'he bare elastic thread l0 forming the core of the elastic yarn may be formed of rubber or-other rubberlike material having the desired stretch characteristics. This thread which is to be twisted, or what'may be called pre-twisted, is preferably wound on a relatively small spool II so that the packages thus formed my be rotated at a speed of say 10,000 R. P. M. or higher. The rubber thread I0 is wound upon this spool in an untwisted condition and under sufficient tension to prevent the entire mass of rubber on the spool from ballooning or bulging outwardly under the high centrifugal force caused by the rapid rotation of the spool. The bare rubber thread I0 is twisted in accordance with the present invention by rotating the spool or package I I about its longitudinal axis and by drawing the thread endwise therefrom over one head.

In Fig. 1 the rubber thread I0 is shown as drawn downwardly from the supply spool I I in an axial direction. In the modification of Fig. 4 it is shown as drawn upwardly from the spool I I in an axial direction, and in the modification of Fig. 5 the thread I0 is shown as drawn horizontally from the spool II in an axial direction.

Referring first to the embodiment of the invention shown in Fig. 1, it will be vnoted that the arrangement is such that the package II extends downwardly from its rotating means so that the thread may be drawn downwardly therefrom. By employing this arrangement the force of gravity is utilized to help advance the thread in a general downward direction from the spool to the spinning mechanism to be described.

The spool II is shown as mounted upon the spindle I2 and the spool may be frictlonally secured to this spindle or may be held in place thereupon by the cap I3. The spindle I2 may, if desired, be driven by a belt but is shown as driven by a small high speed electric motor I4 which motor may be secured to any suitable supporting means such as the supporting rail I5.

It is important, as above stated, to draw the thread I0 from the spool at a'uniform speed so that the twist per inch imparted to this thread will be as near uniform as possible. Therefore in the embodiment of the invention shown in Fig. 1, feed means is provided below the rotating spindle I2 for pulling this thread downwardly at a definite predetermined speed. This means comprises a feed roll I6 which may be driven at any desired speed by the gear I1, vand the rubber thread I0 is held in feeding engagement with this roll by the idler roll I8 which is rotatably supported between the spaced arms I3 of a swinging bracket that is pivotally mounted at I9' upon a support 20. 'I'he arrangement is such that the idler I8 rests by gravity upon the feed roll I6 and this idler may be swung upwardly away from the roll I6 to facilitate threading up of the device.

As the thread I Il unwinds from the rapidly rotating spool I I it will tend to balloon or swing outwardly as shown in Fig. 1. 'I'his is desirable if not excessive, since it helps to get the thread away from the head of the spool, it also helps to take up slight variations in the tension of the thread as it unwinds from the spool. 'I'he size and shape of this balloon may be controlled largely by the position at which the thread guide orpigtail 2I is located below the spindle I2 in axial alignment therewith. This pigtail is preferably pivotally secured to a thread board 22 in a well known manner so that the pigtail may be swung upwardly out :of the way to permit the.

spool I I to be doffed. If desired the thread board 22 may be mounted for vertical adjustment upon its support 20 to thereby move the pigtail 2l toward or from the spool II, to control the ballooning of the thread I0.

The twisted, or pre-twisted thread I0 upon leaving the feed roll I6 may have a textile cover spun thereupon substantially as disclosed in the Foster patent above cited, and the spinning mechanism employed to spin the twisted rubber thread and textile cover together to form the elastic yarn may be of the usual or well known construction. It is shown as provided with roving drafting means and a ring and traveler although a flier type of spinning means may be used.

In the construction shown the spinning mechanism is provided with the usual pairs of drafting rolls 23, 24 and 2 5. The covering material which is preferably a roving or rovings may be supplied to the drafting mechanism from the roving supply spindles 26. Two ends of roving 21 are shown as extending to the drafting rolls, as two ends will give a more uniform product than a single end of roving. These rovings 21 pass through the roving guide 28 supported by a bracket 29 which bracket in turn is secured to the traverse bar 30. This bar 30 as is usual is given a short traverse movement to advance the roving lengthwise of the feed rolls and thereby lessen the wear upon these rolls. It is desirable to impart a similar traverse movement to the rubber thread I0 as it passes downwardly to the nip of the drafting rolls 23 so as to 4bring the roving and rubber thread together at the nip of these rolls. This is readily accomplished by providing a thread guide 3| upon the bracket 29 to travel therewith and which is adapted to guide the rubber thread I0 as it passes from the feed roll I6 to the nip of the rolls 23.

The spinning mechanism is shown as having the usual spinning spindle 32 which is journaled in a bearing 33 mounted upon the fixed support 34 and this spindle is shown as having the usual whirl that is driven by a belt 35 from the rotating drum 36. Upon the spindle 32 is mounted a bobbin 31 upon which the finished elastic yarn 38 is wound. The bobbin 31 as is usual rotates within an opening within the ring rail 39 which is traversed up and down in a well known manner to wind the yarn uniformly upon the bobbin 31. 'I'he ring rail 39 is provided with the usual ring 4I and traveler 4I. Above the upper end of the spindle 32 is provided the thread guide or pigtail 42 carried by the thread lboard 43 and secured thereto bythe usual hinge so that it may be thrown upwardly out of the way of the bobbin to facilitate doiiing.

It is found in practice that in order to produce a balanced elastic yarn the number of windings in one direction of the covering material in one inch of the relaxed elastic yarn should be approximately equal to the number of twists of the rubber core in the opposite direction in this inch of elastic yarn. This, however, is only approximate and may vary with the size of rubber core used relative to the covering material used. Therefore when the twists of the core approximately equal the opposite winding of the cover the lower spindle 32 will be operated at about one-half of the speed of the upper spindle I2 but in the reversed direction so as to remove during the spinning operation about one-half of the twist which was previously imparted to the bare rubber core.

The take-up package 3B may 'be rotated in either a clockwisel or contra-clockwise direction provided the let-off package II rotates in one direction and the take-up package 38 rotates in the opposite direction. That is the package 33 should always be rotated in a direction to reduce the twist imparted to the rubber core by the rotation of the spool I I.

Most of the spinning action which results in winding the textile cover about 'the rubber thread as a core takes place adjacent the discharge side of the ni-p rolls 23, and since the rubber core is stiffer and has a greater contractive tendency than the drafted roving the core takes the central position and the drafted fibers are wound thereabout as a cover as clearly shown in Fig. 2.

It will lloe seen from Fig. I that by operating the feed roll I6 and drafting rolls 23 at the proper speed relative to each other and to the let-o and take-up packages, the amount of twist per inch imparted to the bare rubber thread and the tension of the rubber thread between the feed roll I6 and nip of the rolls 23 may be accurately controlled. This serves to provide the proper number of twists and the proper tension of the rubber core to form a balanced elastic yarn.

Since it is contemplated that the let-olf spool I I will be operated at high speed it may be desirable to Aprovide manually controlled brake means to checkv rapidly the rotation of the spindle I2 after its driving power has been cut off. Therefore this spindle is shown as having a brake disc 44 about which is looped a brake band 45. One end of this 4band is anchored to a fixed post 46 and the other 'end is connected by a spring to an, arm 41 that projects laterally from a shaft 48 rotatably mounted in a bearing 49 and adapted to be turned slightly about its longitudinal axis to apply the brake.

While the construction shown in Fig. 1 has the motor I4 for twisting the thread I0 as it is .pulled .off one end ofthe spool II, it may be desirable in some ,cases to operate the various parts of the machine of the presen-t invention from a single motor so as to correlate accurately the operating speed of the spool II, feed roll I6, drafting rolls, and spinning spindle 31. Therefore in the modied constructions of Figs. 4 and 5, the spindle for supporting the let-oil' package II is shown as provided with a driving whirl instead of the driving motor I4 .of Fig. 1.

In the constructionA shown in Fig. 4 the spool II of rubber thread to be twisted is mounted upon the 4upper end of the vertical spindle 50. This, spindle is journaled in the supporting bracket 5I and may be driven by the whirl 52. Above the spindle 50 is provided the pigtail guide 53 similar to the guide 2I of Fig. 1. The rapid rotation of the spool II causes the thread I0 to balloon as shown, as it passes upwardly to the pigtail 53. It then passes upwardly from this pigtail to the idler roll 54 and then downwardly between the feed roll 55 and cooperating idle roll 56 which may be similar in construction and operation to the rolls I6 and I8 of Fig. 1. From the roll 55 the twisted thread passes downwardly to the drafting rolls 23 to meet the drafted roving 21 and cause this roving lto be spun about the thread I0 as a cover, 'the same as in Fig. l.

It has been found in practice that while the construction of Fig. 1 has the desirable feature of utilizing gravity to facilitate the travel of the thread from the let-olf spool to the take-up package, it is open to the objection that in some cases the outer coils tend to drop down over theY head of the spool as its rotation is being stopped. I'he u'p twisting construction of Fig. 4 avoids this tendency. l

In Fig. '5 the spool I I of rubber thread is mounted upon a horizontal spindle 51 having the opercolorating whirl 58, and the thread I0 upon leaving this spool passes through the guide 59 and then about anI idler 60. From this idler it is pulled downwardly by the feed roll 6I and idler 62. From this point on the operation is the same as in Fig. 4.

In the construction shown in Figs. 4 and 5 it is contemplated that the let-off and take-up spindles and various feed rolls will all be driven from the same source of power so that the speed ratio between these parts will remain constant.

It will be apparent from the foregoing that as a result of the apparatus and method of the present invention the rubber thread that is to form the core of the elastic yarn is pre-twisted in one direction and is then subjected to a spinning operation which removes part of this twist as the covering material is spun thereuponin the opposite direction, and -that these operations are carried out simultaneously and continuously as the rubber thread travels from the let-off package II to the take-up package 38. l

In order that the elastic yarn herein contemplated may be further understood the following tables are given as illustrating a few of the many constructions that may be made by employing the method and apparatus of the present invention.

Tables of construction 1. Gauge of round rubber core, relaxed-- 125S 2. Elastic yarn, relaxed yards per lb.-- 11,000 3. Elongation or total range of stretch of the elastic yarn per cent-; 125 4. Material of cover-2 ends 10 hank combed Sakellaridis roving 12 draft. 5. Length of bare core in 1 yard of elastic yarn inches-- 26 6. Bare rubber core per cent by weight 45 '1. Cover per cent by weight 55 8. Gauge, elastic yarn, relaxed inches .0105 9. Average strength of elastic yarn at break lbs.-- 0.42

. Gauge of round rubber core, relaxed-- Elastic yarn, relaxed yards per lb. 6500 .y Elongation or total range of stretch of the elastic yarn per cent-- 4. Material of cover-2 ends 5 hank combed-peeler roving 12 draft. 5. Length of bare Acore in 1 yard, elastic yarn inches-- 25.5 6. Bare rubber core per cent by weight-- 42 7. Cover per cent by weight 58 8. Gauge, elastic yarn, relaxed 0.0140 9. Average strength of elastic yarn at break` lbs. 0.55

III

1. Gauge of round rubber core, relaxed-- 75 2. Elastic yarn, relaxed yards per lb.-- 3700 v 3. Elongation or total range of stretch of the elastic yarn per cent-- 120 4. Material of cover- 2 ends 3 hank combed-peeler roving 12 draft. 5. Length of bare core in 1 yard, elastic yarn inches-- 24.5 6. Bare rubber core per cent by weight-- 37 7. Cover per cent by weight-- 63 8. Gauge, elastic yarn, relaxed 0.020 9. Average strength of elastic yarn at break lbs.-- 1.09

While the covering for the elastic yarn shown in Fig. 2 is preferably formed of a drafted roving or rovings, it is contemplated that the method and apparatus of the present invention may be `employed to apply a textile yarn or other form of strand about the rubber thread as a cover. Through the present invention it is possible to produce an elastic yarn which is well balanced and in which the helical windings of the drafted roving blend together to form a soft smooth cover that closely resembles ordinary textile yarn in feel and appearance.

Having thus described our invention, what we claim and desire to protect by Letters Patent is:

1. The method of making a balanced elastic yarn having la twisted rubber core and a textile cover spun thereupon, which consists lin rotating a package of bare rubber thread and pulling the thread endwise therefrom to twist it in one direction, and advancing this thread as it is twisted and a textile roving towards spinning means to thereby spin said roving about the core in the opposite direction so as to form a helical cover upon the core adapted to balance the twist of the core and hold it stretched.

2. The method of making an elastic yarn having a twisted rubber core and a cover spun thereupon in the opposite direction, which consists in rotating a package of rubber thread and pulling the thread endwise therefrom to twist it in one direction, and advancing this thread as i't is twisted and a covering strand towards spinning means to thereby spin said strand about the core in the opposite direction so as to wind it about the core as a cover and reduce the twist of said core.

3. The method of making an elasticl yarn having a twisted rubber core and a cover spun thereupon in the opposite direction, which consists in rotating a package of rubber thread andpulling the thread endwise therefrom in a downward direction to twist it in one direction and advance this thread in a downward direction as it is twisted towards spinning means, feeding a covering strand also towards said spinning means to thereby spin this strand about the core in the opposite direction to wind it about the core as a cover.

4. The method of making an elastic yarn having a twisted rubber coreand a cover spun thereupon in the opposite direction, which consists in rotating a package of rubber thread and pulling the thread endwise therefrom to twist it in one direction, advancing the thread as it is twisted towards spinning means and simultaneously stretching it a predetermined amount, feeding a covering strand also towards said spinning means to thereby spin this strand about the core in the opposite direction to wind it about the core as a cover.

5. I'he method of making an elastic yarn having a twisted rubber core and a cover spun thereupon in the opposite direction, which consists in rotating a let-off package of rubber thread and pulling the thread downwardly therefrom to twist the thread and utilize the force Aof gravity in removing the thread from said package, simultaneously rotating the take-up package of spinning means for this thread in a direction to reduce the twist of this thread as it is wound on said take-up package, and delivering a covering strand to said spinning means so as to spin it about said thread as a cover.

6. 'I'he method of making an elastic yarn having a twisted rubber core and a cover spun thereupon in the opposite direction, which consists in rotating a let-off package of rubber thread and pulling the thread downwardly therefrom to twist the thread and utilize the force of gravity in removing the thread from said package, simultaneously rotating the take-up package of spinning means for this thread in a direction to reduce the twist of this thread as it is wound on said take-up package, delivering acovering strand to said spinning means so as to spin it about said thread as a cover and controlling the stretch of said rubber thread as it is delivered to said spinning means.

7. The method of making an elastic yarn'having a twisted and tensioned rubber core and a cover spun thereupon, which consists in rotating a package of rubber thread and pulling the thread endwise therefrom at a uniform rate of speed to twist it in one direction, advancing this thread as it is twisted at another point at a different uniform speed to thereby tension the thread a predetermined amount and feed it towards spinning means, delivering a covering strand also towards said feeding means to thereby spin said strand about the core in the opposite direction so as to wind it about the core as a cover.

8. The method of making an elastic yarn having a twisted rubber core and a cover of textile bers spun thereupon in the opposite direction, which consists in rotating a package of rubber thread and pulling the thread endwise therefrom in a downward direction to twist it, drafting unspun textile fibers and advancing them towards spinning means, and advancing said thread as it is twisted towards said spinning means to thereby spin the textile fibers about the core in an opposite direction to wind it thereupon as a cover.

FAYE'I'IE D. CHI'I'IENDEN. y KENNETH J. RUPPRECHT.

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