US3283543A - Thread feeding and tensioning apparatus for knitting machine - Google Patents

Description

Nov. 8, 1966 L. KING 3,283,543

THREAD FEEDING AND TENSIONING APPARATUS FOR KNITTING MACHINE Filed April 16, 1964 2 Sheefs-Sheet 1 J L, W TTF I 36 "[W H M'\" w 1 i l ;ii|| I I i /4 l6 Par-M PM kw-l m 00-0 000000000 2 OOOOOOHOI O 0% 2 t 44 42 0 l8 1 80 1 60 Lawrence King 82 68 INVENTOR BY 40 54 WWO ATTORNEY Nov. 8, 1966 1.. KING 3,283,543

THREAD FEEDING AND TENSIONING APPARATUS FOR KNITTING MACHINE Filed April 16, 1964 2 Sheets-Sheet 2 FIG 5 Lawrence King INVENTOR United States Patent 3 233,543 THREAD FEEDING A ND TENSIONIN G APPARA- TUS FOR KNITTING MACHINE Lawrence King, New York, N.Y., assignor to Rosfor Mills Corporation, New York, N.Y., a corporation of New York Filed Apr. 16, 1964, Ser. No. 360,211 3 Claims. (Cl. 66-432) This invention relates to circular knitting machines and more particularly it relates to apparatus for feeding thread to such machines under uniform tension. It has particular reference to elastic or stretchable threads which are knitted into tubular items such as garments.

It is obvious that in order to knit a garment which is commercially acceptable, the finished garment must be free from imperfections or irregularities. When the garment is to be knit of elastic thread, the problem becomes more acute since minor variations in tension will tend to variably elongate or stretch the thread, thus creating a finished garment with some of its threads stretched more than others. This not only tends to create unsightly wrinkles and gathers, but also produces a garment which does not fit properly. Neither of these conditions is acceptable in a quality garment and it hence becomes necessary to provide a means for applying a uni-form tension to all elastic threads being fed to the knitting machine.

Another, though no less serious, problem occurs when the elastic thread feeding means is intermittently started and stopped. If the thread feeds freely off a supply roll, a sudden stopping of the knitting machine may cause a slack to occur in the thread at some point between the supply roll and the machine knitting needles. If the thread is at all twisted, such a slack may allow the thread to kink or knot. However, even if the thread is not twisted, the slack may vary between different adjacent threads. Then, when the knitting machine is started again, the slack must be taken up, but since the slack in each thread might be different, the result might again be a garment having an uneven appearance due to variable tension on each of the threads which are knitted to form the garment. Also, if knots or kinks occur when the thread is slack, they may remain in the thread and become knitted into the finished garment, thus ruining its appearance.

In the conventional form of circular knitting machine, the thread is supplied from a plurality of juxtaposed thread supply rolls and is fed downwardly to a series of circularly arranged knitting needles. Recognizing that a free feed of the thread will not produce a uniformly knitted garment, various attempts have been made to interpose a tensioning means between the thread supply rolls and the knitting needles, but such past attempts have not been altogether satisfactory. One prior art approach was to feed the thread between an intermeshing pair of gears or toothed rollers which were to provide a tensional force on the thread. However, the interaction of the mating gear teeth caused the thread to become mangled or crimped and thus unsuitable for the knitting of smooth garments. Another approach taken in the prior art was to utilize adjustable tapered rollers, but these tapered rollers were difficult to set and adjust and failed to provide a positive, non-slipping thread feeding and tensioning means. Other prior art approaches failed to properly synchronize the tensioning means with the knitting machine itself with the result that intermittent starting and stopping of the machine would not necessarily start or stop the tensioning means, and thus the thread fed to the machine was not uniformly ten-sioned.

It is, therefore, an object of the present invention to overcome the difficulties and deficiencies associated with the prior art and to provide an improved thread feeding and tensioning apparatus for supplying elastic thread to a circular knitting machine.

Another object of the present invention is to provide apparatus for feeding elastic thread under uniform tension to the needles of a circular knitting machine.

Another object of the present invention is to provide an elastic thread tensioning means which operates in synchronism with a machine for knitting the thread and which thus provides a positive feed for the thread.

Another object of the present invention is to provide thread tensioning apparatus for a circular knitting ma- Other objects, advantages and salient features of the 7 present invention will become apparent from the follow- 'ing detailed description, which, taken in connection with the annexed drawings, discloses a preferred embodiment thereof.

Referring to the drawings:

FIGURE 1 is a side elevational view of a portion of i a circular knitting machine having a thread feeding and tensioning apparatus, in accordance within the principles of the present invention, affixed thereto;

FIGURE 2 is a fragmentary bottom view taken substantially along line 22 of FIGURE 1;

FIGURE 3 is a fragmentary developed side elevational view taken substantially along line 3-3 of FIG- URE 2;

FIGURE 4 is a transverse sectional view taken sub- 5 stantially along line 44 of FIGURE 3;

FIGURE 5 is a fragmentary end elevational view taken substantially along line 55 of FIGURE 4; and

FIGURE 6 is a fragmentary sectional view taken substantially along line 66 of FIGURE 5.

In accordance with the principles of the present inventron and as can be seen from the various figures therei of, there is provided a circular knitting machine generally designated 10, a support means secured to the knitting machine and generally designated 12, a mounting member generally designated 14 aifixed to the support means, a tensioning means generally designated 16 secured to the mounting member, a drive means generally designated 18 also secured to the mounting member and operable to drive the tensioning means, and a knitting machine drive mechanism generally designated 20 which operates the knitting machine 10.

Referring now to FIGURE 1, the upper portion of a circular knitting machine 19 is shown as having a cam plate 22 and a needle mounting plate 24 juxtaposed beneath the cam plate and rotatable relative thereto. A plurality of conventional needles, not shown, are pivotally aflixed to the needle mounting plate 24 and a plurality of feed-in heads 26 are equally spaced about the periphery of the cam plate 22. As the feed-in heads 26 supply thread to the needles, the needles and their mounting plate 24 are rotated relative to the cam plate 22, and

this relative rotation effects a knitting operation to produce a tubular knitted article 28 in a manner which is well known to those skilled in the art.

A support means 12 extends above the knitting machine 16 to support the thread, the thread guide means, and the tensioning means. The support means 12 is formed by a stationary elongated central shaft 30 having a thread support plate or ring 32 suitably attached to the shaft 30,

such as by a plurality of spaced spokes or ribs, not shown. 7

The plate or ring 32 has a flat upper surface 34 from which a plurality of spaced pins 36 project upwardly. The

Patented Nov. s, was

3 pins 36 serve as a mounting means for supply rolls or coils 38 of thread 40 which are placed over the pins 36 to rest upon the flat surface 34. Although only one such coil or supply roll 38 is shown in FIGURE 1, it should be understood that this is only for ease of illustration and that, in actual operation, a plurality of such rolls 38 are used with one being placed over each pin 36 to supply a plurality of threads 40 to the knitting machine 10.

While the thread 49 can be of any suitable material to be utilized in knitting the article 28, the presesent invention is particularly directed toward elastic or stretchable threads such as those formed of spandex fibers. Such threads are sol-d commercially under the trademark Lycra manufactured by E. I. du Pont de Nemours and Co. of Wilmington, Delaware.

A pair of guide roller mounting members 42 are suitably afiixed to the support means 12, with one of such members 42 being located at the upper end of the shaft 30 and the other of such members being located near the lower end of the shaft 30 adjacent the knitting machine It). A plurality of rotatable guide rollers 44 are spaced from the peripheries of these members 42 by suitable means such as outwardly extending legs 44 integral with the members 42. Between the upper member 42 and the support ring 32, an eyelet mounting ring 46 is suitably afiixed to the shaft 36 by means of spokes or ribs. A plurality of equally spaced spokes 48 extend away from the periphery of the ring 46 and are provided at their outer ends with eyelets 56 through which the thread 46 passes.

As can be seen from FIGURE 1, a coil or supply roll 38 is placed over a pin 36 to rest upon the flat upper surface 34 of the thread support ring 32. Thread 40 from the coil 38 feeds upward through an eyelet 50 and over an upper guide roller 44, and then traverses downward inside the rings 46 and 32 and finally feeds into the tensioning means 16. This tensioning means applies a constant and uniform tension to each thread and after a thread 40 exits from the tensioning means, it feeds downward and over a lower guide roller 44 and into a feed-in head 26 which supplies the thread 40 to the needles. It can be seen that for each supported supply coil 38, there is an associated eyelet 50, upper and lower guide roller 44, feed-in head 26 and special portion of the tensioning means 16, so that each individual thread 40 is fed from its supply roll to the needles under exactly the proper conditions of speed and tension. When all of the threads 40 are considered together, the means for feeding and tensioning them comprises the apparatus which is the subject matter of the present invention.

Referring now to FIGURES 2 through 6, it will be seen that the mounting member generally designated 14 is formed as a fixed ring which is attached to the shaft 30 by means of integral upper spokes 52 and lower spokes 54. As can be seen from FIGURE 4, the ring or mounting member 14 is generally tubular in configuration and rectangular in cross-section, and when the ring is mounted in its norm-a1 position on the shaft 30, a wall 56 forms the upper Wall, a wall 58 forms the lower wall, a wall 649 forms the inner wall which is close to the shaft 30, and a wall 62 forms the outer wall.

The tensioning means 16 is supported by the mounting member 14 and includes a plurality of coacting pairs of rollers 64 and 66. Each of these rollers is generally cylindrical in shape, is provided with a smooth outer surface andis fabricated of a plastic material, preferably nylon. Each pair of rollers 64 and 66 is spaced from the adjacent pairs so that each pair can be individually and positively driven by the drive means 18. One individual thread 40 feeds between each roller 64 and its associated roller 66.

Only the roller 64in each pair of rollers is positively driven by the drive means 18. The roller 66 in each pair is merely freely mounted as an idler and is driven by means of frictional contact from the driven roller 64. Each roller 64 is provided with a stub shaft 68 which extends through apertures in the side walls 60 and 62 of the mounting member 14, and, adjacent the'inner Wall 60, a

spur gear 70 is mounted on the end of the stub shaft 68. Each roller 66 is also provided with a stub shaft 72 which extends through the walls 66 and 62 of the mounting member 14, but the apertures through which these shafts 72 pass are formed as elongated slots 74, as can be seen in FIGURES 3 and 6. Adjacent the inner Wall 69, the ends of the shafts 72 are flared outwardly as shown at '76 to thus permit the shafts to slide within the slots 74 but to prevent them from retracting through the slots.

The purpose of providing the slots 74 for the shafts 72 which mount the rollers 66 is to permit the rollers 66 to be slidable toward and away from their associated rollers 64 to thereby accommodate threads 40 of varying diameters. However, means are provided for spring-biasing each roller 66 toward its associated driven roller 64. This means, as shown in FIGURES 4 through 6, includes a U- shaped bracket having an elongated leg 78 in parallel juxtaposition to the outer wall 62, another elongated leg 80 in parallel juxtaposition to the inner wall 60, and a transverse leg 82 interconnecting the legs 7 8 and 80 at one end thereof. At the end of the bracket opposite the wall 82, a slot 84 is formed in the legs 78 and 80 for reception of the shaft 68, as shown in FIGURE 5. Aligned apertures are formed through the legs 78 and 86 and these apertures are sized to accommodate the shaft 72. It can thus be seen that the shaft 72 and its interconnected roller 66 are mounted within the U-shaped bracket and that the bracket and shaft are slidable toward and away from the roller 64, within the shaft 72 being slidable within the slots 74.

When the driven shaft 68 becomes fully positioned within the bracket slot 84, the slidable motion of the bracket is halted and in this position, the rollers 64 and 66 should be in contact and the shaft 72 should be at the near end of the slot 74. This condition is shown in FIG- URE 5 and should only occur when no thread 40 is present between the rollers 64 and 66. When a thread 40 is introduced between the rollers, the roller 66 must move slightly away from its associated roller 64 to accommodate the thickness of the thread. This slight moving causes the shaft 68 to move slightly out of its slot 84 and causes the shaft 72 to move slightly toward the far end of its slot 74. Each bracket is spring-biased to normally urge the rollers 64 and 66 toward one another and to resist this slight sliding or parting movement of the rollers. To this end, a pin 86 extends inward from the bracket leg 78 and a similar aligned pin 83 extends inward from the outer mounting member wall 62. Between these pins 86 and 88, a coil tension spring 90 is mounted, and this coil spring pulls the bracket toward the pin 88 and thus biases the rollers 64 and 66 toward one another.

In order to operate the gears 70 and cause their associated pairs of rollers 64 and 66 to tension the thread 40, a drive means 18 is provided. The drive means includes a ring gear 92 having an upper series of teeth 94 and a lower series of teeth E6. The ring gear 92 is slidably mounted within a groove 98 formed in the lower portion of the inner wall 60 on the mounting member 14 as shown in FIGURE 4. Of course, if desired, suitable bearing means may be provided between the ring gear and the mounting member, and although bearing means have not been illustrated in order to simplify the description of the invention, they will be readily apparent to those skilled in the art. The ring gear 92 can also be provided with a series of spaced spokes or ribs 100 which interconnect to a hub 102 surrounding the shaft 30, as shown in FIGURE 6. In operation, the ring gear and its interconnected hub are rotated relative to the mounting member and this ring rotation causes the roller driving gears 70 to rotate, since these driving gears 76 mate with the upper series of ring gear teeth 94, as shown in FIGURE 3.

The drive means 18 also includes a drive gear 104 which mates with the lower series of ring gear teeth 96, as shown in FIGURES 2 and 4, and which eifectuates the rotation of the ring gear 92. The drive gear is suitably mounted within a bearing 106 aflixed to the lower Wall 58 of the mounting member 14, as shown in FIGURES 2 and 4. The drive gear is operatively connected to a variable speed control unit 108 by flexible means in the form of links 110 having universal joints 112 therein. The universal joints permit the links 110 to be interfolded and bent in such a manner that the variable speed control unit 108 can be directly connected to the knitting machine drive mechanism 20 for operation in synchronism therewith.

It can thus be seen and appreciated that the drive means 18 and thus the tensioning means 16 are interconnected with and operable in synchronism with the knitting machine drive mechanism 20 and hence with the knitting machine itself. The variable speed control unit 108 is provided with a manually adjustable means 114, as shown in FIGURE 2, for varying the setting of the unit. By altering the setting of the adjustable means 114, the tension which the roller pairs exert on the thread 40 can be varied accordingly. This can be best understood by first assuming a condition wherein the unit 108 is adjusted to substantially the same speed as the knitting machine drive mechanism so that thread 40 is fed to the needles at just the same speed at which the needles knit it. In such a condition, there would be no tension at all on the thread except that caused by friction. However, if the unit 108 is adjusted to run the rollers at a speed slightly slower than that of the knitting machine, the result is that the roller pairs fail to supply the thread as fast as the needles are knitting it and consequently, between these roller pairs and the needles, the thread is under tension due to the pull of the needles. Naturally, the slower the unit 108 is set, the slower will be the speed of the rollers and hence the greater will be the tension on the thread.

Since a single drive gear 104 drives the ring gear 92 and causes it to rotate, and since this ring gear rotation causes the roller driving gears 70 to rotate, it can thus be considered that the drive gear 104 positively drives the tensioni-ng rollers 64 and 66. Since each pair of rollers is positively driven from the same source, each thread 40 is subjected to the same amount of tension and consequently all of the threads are delivered to the needles with exactly the amount of elongation. A further feature of the present apparatus is that the tensioning means 16 operates responsively to the knitting machine drive means 20. Thus, if the knitting machine 10 is stopped for some reason, the feeding of the threads 40 is also simultaneously stopped and when the knitting machine is started again, the threads will continue feeding at exactly the same speed and tension as was present prior to the knitting machine stoppage. It will thus be appreciated that the knitting machine 10 can be started and stopped several times during the process of producing a single knitted article 28, but all of the thread 40 which is utilized to form the article will be delivered to the needles with exactly the same tension and hence exactly the same degree of elongation.

In operation, the knitting machine operator determines exactly what degree of tension should be applied to the threads 40 and he sets the manually adjustable means 114 accordingly. The knitting machine 10 is then started and the knitting machine drive means 20 puts the plates 22 and 24 into relative rotation. Operation of the drive means 20 produces a responsive but selectively slower operation of the variable speed control unit 108 and when the unit 108 starts to operate, it transmits power through the links 110 and causes the drive gear 104 to rotate. Since the drive gear 104 is fixed in position and in engagement with the lower series of teeth 96 on the ring gear 92, rotation of the drive gear 104 causes the ring gear to move relative to the mounting member 14 and to revolve about the shaft 30. Such ring gear movement causes the many spur gears 70, which are engagement with the upper series of teeth 94 on the ring Meanwhile, each of the various threads 40 has been 1 fed upward off its coil 38, through an eyelet 50, over an upper guide roller 44 and back down to pass between a pair of rollers 64 and 66. Since the rollers in the pair are biased toward one another by means of the tension spring 90, each ro l ler tightly grips against one side of the thread 40 and rotation of the driven roller 64 causes a corresponding opposite rotation of the roller 66 to hence feed the thread 40 downward toward the needles. Since the rollers 64 and 66 are formed with smooth outer surfaces, the threads passing between them will not be mangled or crimped in any way.

After the threads 40 pass from between the rollers 64 and 66, they proceed downward over lower guide rollers 44, through feed-in heads 26 and into the needles mounted on the plate 24. Since the speed ofthe knitting machine 10 is somewhat faster than the speed of the tensioning means 16, the needles tend to utilize the thread faster than it is being supplied to them from the tensioning rollers 64 and 66, and since the needles cannot get the thread 40 fast enough, they pull upon that thread available to them and thereby elongate it, thus applying a tension to the threads. The tension is uniform between each pair of tensioning rollers and each associated needle and the result is that all threads knitted into the article 28 are tensioned or elongated exactly the same amount.

After reading the foregoing detailed description, it will be apparent that the objects set forth at the outset of this specification have been successfully achieved. Accordingly,

What is claimed is:

1. In a knitting machine having a plurality of circularly arranged needles, a plurality of thread supply rolls providing elastic thread for the needles and a knitting machine drive mechanism, the improvement which comprises apparatus for feeding the elastic thread to the needles under a selectively variable, constant and uniform tension,

said apparatus including a mounting member in the form of a fixed ring juxtaposed above the needles in the knitting machine,

said ring including an inner vertically extending wall and a juxtaposed generally parallel, outer wall defining a space therebetween,

a plurality of pairs of thread tensioning rollers carried by said mounting member with said rollers positioned on the outside of said outer wall of said rlng,

each of said pairs of thread tensioning rollers including coacting, smooth surfaced, rollers having cylindrical portions between which the thread passes,

each of said rollers including a stub shaft rotatably supported by said ring,

said stub shaft of one of said rollers of each of said pairs extending through said outer and inner walls of said ring and carrying a roller gear on the inside of said ring,

a common tensioning roller drive means operatively associated with all of said roller gears, resilient means carried within said space and operatively engaging said stub shaft of the other roller of each of said pairs to urge said other roller toward said nected with tlhe knitting machine drive mechanism '1? 5 and being operable independently of the knitting ma- References Cited by the Examiner sai c l n dnge bff i vided with two se arate sets UNITED STATES PATENTS 1 s of 1;; r 1 g .p p 1,097,115 5/1914 Wutsch 66-132 a drive gear operatively interconnected with said var- 5 2,290,628 7/1942 Alderfer 66 132 iable speed control means and interengeuging with 2318998 5/1943 Ingaus 66 132 one of said sets of teeth of said ring gear, I 2,542,816 2/1951 Keflt 66-132 the other of said sets of teeth of said ring gear inter- 8 1/1952 Heller 66 132 engaging with n of Said roller gears, 2,697,337 12/1954 BI'O'WII et :al. 66-56 operation of the knitting machine causing a synchro- 1O 2736178 2/1956 Lawson 66 56 nized and simultaneous driving of said thread ten- 3,010,299 11/1961 Shannon 66'56 sioning rollers to feed thread to the needles, and ad- 3,158,013 11/1964 Mfmday 66 56 justment of said variable speed control means eflect- 3325570 12/1965 Mlslhcon 66 132 ing a simultaneous and uniform modification of the tension on the elastic thread being fed toall of the 15 FOREIGN PATENTS needles of the knitting machine. 1,045,587 12/1958 Germany- 342,297 1/ 1931 Great Britain. 456,919 11/ 1936 Great Britain. 745,909 3/ 1956 Great Britain. 773,090 4/ 1957 Great Britain.

2. The improvement defined in claim 1 wherein said variable speed control means is operatively interconnected with the knitting machine drive mechanism for responsive operation synohronously therewith, and flexible means 20 'operatively interconnecting said variable speed control MERVIN STEIN Primary Examiner means with said drive gear.

3. The improvement defined in claim 1 wherein said DONALD PARKER Examme cylindrical portions of said rollers are formed of nylon. 25 R. FELDBAUM, Assistant Examiner.

Claims (1)

1. IN A KNITTING MACHINE HAVING A PLURALITY OF CIRCULARLY ARRANGED NEEDLES, A PLURALITY OF THREAD SUPPLY ROLLS PROVIDING ELASTIC THREAD FOR THE NEEDLES AND A KNITTING MACHINE DRIVE MECHANISM, THE IMPROVEMENT WHICH COMPRISES APPARATUS FOR FEEDING THE ELASTIC THREAD TO THE NEEDLES UNDER A SELECTIVELY VARIABLE, CONSTANT AND UNIFORM TENSION, SAID APPARATUS INCLUDING A MOUNTING MEMBER IN THE FORM OF A FIXED RING JUXTAPOSED ABOVE THE NEEDLES IN THE KNITTING MACHINE, SAID RING INCLUDING AN INNER VERTICALLY EXTENDING WALL AND A JUXTAPOSED GENERALLY PARALLEL, OUTER WALL DEFINING A SPACE THEREBETWEEN, A PLURALITY OF PAIRS OF THREAD TENSIONING ROLLERS CARRIED BY SAID MOUNTING MEMBER WITH SAID ROLLERS POSITIONED ON THE OUTSIDE OF SAID OUTER WALL OF SAID RING, EACH OF SAID PAIRS OF THREAD TENSIONING ROLLERS INCLUDING COACTING, SMOOTH SURFACED, ROLLERS HAVING CYLINDRICAL PORTIONS BETWEEN WHICH THE THREAD PASSES, EACH OF SAID ROLLERS INCLUDING A STUB SHAFT ROTATABLY SUPPORTED BY SAID RING, SAID STUB SHAFT OF ONE OF SAID ROLLERS OF EACH OF SAID PAIRS EXTENDING THROUGH SAID OUTER AND INNER WALLS OF SAID RING AND CARRYING A ROLLER GEAR ON THE INSIDE OF SAID RING, A COMMON TENSIONING ROLLER DRIVE MEANS OPERATIVELY ASSOCIATED WITH ALL OF SAID ROLLER GEARS, RESILIENT MEANS CARRIED WITHIN SAID SPACE AND OPERATIVELY ENGAGING SAID STUB SHAFT OF THE OTHER ROLLER OF EACH OF SAID PAIRS TO URGE SAID OTHER ROLLER TOWARD SAID DRIVEN ONE ROLLER OF SAID PAIR TO THEREBY DRIVE SAID OTHER ROLLER BY FRICTIONAL CONTACT, SAID COMMON TENSIONING ROLLER DRIVE MEANS INCLUDING A RING GEAR SLIDINGLY MOUNTED IN A GROOVE IN SAID INNER WALL OF SAID RING AND ROTATABLE RELATIVE TO SAID RING, A VARIABLE SPEED CONTROL MEANS OPERATIVELY INTERCONNECTED WITH THE KNITTING MACHINE DRIVE MECHANISM AND BEING OPERABLE INDEPENDENTLY OF THE KNITTING MACHINE DRIVE MECHANISM, SAID RING GEAR BEING PORVIDED WITH TWO SEPARATE SETS OF TEETH, A DRIVE GEAR OPERATIVELY INTERCONNECTED WITH SAID VARIABLE SPEED CONTROL MEANS AND INTERENGAGING WITH ONE OF SAID SETS OF TEETH OF SAID RING GEAR, THE OTHER OF SAID SETS OF TEETH OF SAID RING GEAR INTERENGAGING WITH ALL OF SAID ROLLER GEARS, OPERATION OF THE KNITTING MACHINE CAUSING A SYNCHRONIZED AND SIMULTANEOUS DRIVING OF SAID THREAD TENSIONING ROLLERS TO FEED THREAD TO THE NEEDLES, AND ADJUSTMENT OF SAID VARIABLE SPEED CONTROL MEANS EFFECTING A SIMULTANEOUS AND UNIFORM MODIFICATION OF THE TENSION ON THE ELASTIC THREAD BEING FED TO ALL OF THE NEEDLES OF THE KNITTING MACHINE.

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