CA1237103A - Device for feeding yarn into a circular knitting machine - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Yarn feeding device for feeding thread F to needles A of a machine for knitting stockings and similar products operating with a needle cylinder 51 in a continuous one-way motion and with an additional thread guide 98 which cyclically moves beyond the needles in an arc of needles intended to form, without applying tensions to the yarn, chains of loops in the heel of the stocking by placing the thread in front of the needles when they are lifted. Several additional sinkers 59 are positioned above the traditional sinkers 55, and a cam 61 operates the additional sink-ers 59. The cam 61 is in turn operated by two sector gears 63-65, with an interposed idle pinion 67 and with the intervention of rods 73-77 which, by interfering with corresponding pegs 71-75 in sector gears 63-65, stop either one of them to stop cam 61 or to move beyond it. In this manner, the yarn F supplied by the thread guide 98 to the needles A to form the heel is of greater length than that of the arc of the corresponding needles and equal to the length of the loops that the needles must form in each chain.

Description

~237~3 The invention concerns a device Eor feeding yarn in circular stocking knitting and other macl~ines for the formation of a heel pouch with continuous motion. There i5 a known circular machine in which the needle cylinder has a one-way continuous rotary motion and an additional thread guide cyclically moves beyond the needles in an arc of needles intended to form the heel by placing the thread in front of the lifted needles.
In this known circular stocking knitting machine, a heel is formed with a continuous motion of the needle cylinder by means of an additional thread guide moving coaxially with the cylinder;
this thread guide follows the needle cylinder, stops before a loop-forming position to feed thread to the needles in an arc of needles which pass in front of it, then, at an angular velocity gr~ater than that of the cylinder, moves beyond the needles in an arc of lifted needles to place in front of them the thread, which is formed into loops with a further lowering at a further loop-forming position, and finally, starts again to follow the cylin-der.
This machine has some drawbacks arising from the fact that the thread fed by the thread guide is not of a leng-th matching the development of the loops to be formed, so that the latter, once formed, are held very tight because the thread is under excessive tension.
An object of the present invention is to eliminate this drawback. The present invention, solves the problem of feeding yarn to stocking knitting and similar machines opera-ting with a ~.

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continuous rotation of the needle cylinder, without tension on -the thread during the formation of a pouch of loops by proceeding to accumulate a length of thread exceeding the length of the arc of needles that is fed.
More particularly according to the present invention there is provided a device ~or feeding yarn in stocking knitting and similar machines for the formation of a heel pouch with con-tinuous motion in the same direction of the needle cylinder and having an additional hollow thread guide which cyclically moves beyond the needles in an arc of needles to form heel o~ the stock-ings and places the thread in front o~ the lifted needles, which form with it chains of loops in the heel, said device comprising several additional sinkers, arranged in an arc concentric with said needle cylinder, a cam structure to operate said sinkers with the centripetal forward motion and subsequent withdrawal, and an additional thread guide placed under a small platelike member.
In a preferred embodiment, the present invention comp-rises an arc o~ additional sinkers and a cam structure to operate these sinkers which is movable in order to cause a centripetal advance of the sinkers and their subsequent withdrawal. The addi-tional sinkers are advantageously placed above the ring of tradi-tional sinkers, which are then arranged with the control heels projecting downwardly. I'he cam structure is operated, relative to the ring o~ the sinker cylinder, with the aid of two coaxial sec-tor gears and transmission pinion (idle) and with the intervention of rods which stop both sector gears, to cause the cam to stop and to move beyond.

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~;~3~ 3 Some of the advantayes obtained by means of the present invention are that the thread used in Eorming the loops which form each chain in a heel pouch is free of tension; and the operation of the circular machine with continuous cylinder ro-tation is more regular even with long working periods; and the device is also applicable to existing machines.
The advantages and other features of the present inven-tion will be more fully described with reference to the accompany-ing drawings, in which:
Figure 1 shows a plan view of the means to operate -the additional thread guide;
Figure 2 shows an overall vertical section of a device according to the invention, Figure 3 shows a plan view of a detail of the device;
Figure 4 shows one operating method, Figure 5 shows an alternate operating method; and Figure 6 shows the operation of the additlonal thread guide.
In Figures 1 through 3, 51 shows the needle cylinder, 53 ~ 20 the ring engaged with the needle cylinder 51 around its upper edge, to ~orm radial housings for the traditional sinkers 5. In Figure 2, the ring of sinkers 53 is deployed to form radial chan-nels ~or the sinkers in the bottom part, the sinkers 55 having a heel 55A projecting downwardly to cooperate with a ring structure 57 below corresponding to the so-called traditional sinker hous-ing. The arrangement is necessary because, above the ring 53, ~.

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~237~3 provision is made for a set of auxiliary sinkers 5g, which are for the recovery of the thread previously arranged in a sector of the circumEerence of the needle cylinder whose needles form the heel 59A. I'hese recovery sinkers 59 have the control heel 59A project-ing upwardly to cooperate with a cam structure 61, which also constitutes a housing for the recovery sinkers 59, deployed along an arc of a circle. This structure 61 is so carried as to clutch by friction and rotate relative to the ring 53 for the sinkers 55, and to move alternately relative to it. The structure 61 is integral with a sector gear 63 with external teeth. A second section gear 65 with internal teeth is provided ~or in a housing for~ed by the ring 53 of the sinkers 55, integral with the cylin-der 51, and also capable of rotating, but clutching by friction relative to the ring 53. On the ring 53 of sinkers 55, there is mounted an idle pinion gear 67, which is capable of rotating spon-taneously, and which simultaneously engages the two sectors 63 and 65. Sector 63 has a contact peg 71, cooperating with a stop rod 73, movable to interfere with the peg 71 or to avoid it.
Similarly, sector 65 has a contact peg 75, capable of cooperating with a stop rod 77, (see Figure 3) movable to interfere with the peg 75 or to avoid it. The stop rods 73 and 77 can be controlled radially and/or angularly to reach the two positions.
As long as neither rod 73 nor rod 77 interferes with its respective peg 71 and 75, as shown in Figure 3, the two sector gears 63 and 65 rotate, carried along by ring 53, with which they are engaged by friction. When rod 77 is caused to project to ;.: ,,,~; .

~Z3~7~3 interfere with peg 75, it stops sector 65; at this time, pinion gear 67, continuing its motion with ring 53, starts rolling along the teeth of sector 65, and thereby causes sector 63 to move for-ward at an angular velocity which is almost twice the angular veloci-ty of the needle cylinder 51; with this, the cam profile of cam structure 61 acts upon the sinkers 59, causing their cen-tri~
petal radial motion. By withdrawing the rod 77, the relative motion is interrupted between ring 53, sector 65 and sector 63 with cam 61, and the sinkers 59 tend to remain in a projecting position. When rod 73 with its centripetal projection acts upon contact 71, sector 63 is stopped and therefore cam 61 is stopped, while the rotation of ring 53 continues; it follows from this that, at this point, the sinkers 59 move beyond cam 61, which is stopped, and return, with a centrifugal motion, toward the out-side; as a result of the reverse rotation of pinion 67, a rapid forward motion of sector 65 is also obtained. At the time the retaining action of rod 73 on peg 71 ceases, sectors 65 and 63 resume their reciprocal positions relative to ring 53, as shown in Figure 3, and parts 53, 65 and 63 start rotating again with the needle cylinder 51. It should be noted that the centripetal for-ward motion of the sinkers 59 takes place gradually as a result of the profile of cam 61, which accelerates relative to the motion of the needle cylinder 51, and the centrifugal motion of the sink-ers 59 also takes place gradually, but in the opposite direction, when the structure 61 is stopped, again as a result of its pro-file, which always and in any case acts upon the heels 59A of the sinkers 59; in the first stage, starting from the rear sinkers, B

~2~37~a3 3 and in the second stage starting from the front sinkers in the sector oE sinkers 59 in the direction of the rotation of the needle cylinder 51. These centripetal movements of the additionaL
sinkers 59 cause more yarn to be pulled out than is due to the motion of the thread guide 98, when the latter is forced to move rapidly beyond the needle cylinder 51; the sinkers 59, moving forward, cause the thread F to follow the pattern shown in Figure 5, pulling out a length of yarn greater than that of the arc of needle cylinder 51, relative to the last needle AX which has taken and knitted the thread.
When the sinkers 59 slide relative to sector 63 in the direction of the rotation of the needle cylinder 51, the sinkers 59 withdraw in a centrifugal direction and thus yield the thread and enable it to form the subsequent loops as the needles are lowered, without applying tension to the yarn.
The device described above is assisted by a transmission system to operate the additional thread guide 98 to enable it to accelerate relative to the needle cylinder to move at the same speed as the needle cylinder and to stop. To obtain this, provi-sion is made for a device, as shown in Figures 1 and 2, in combin-ation with structure 91 which supports the small plate-like member or hub 92 rotating coaxially and above the needle cylinder 51, which hub member 92 is operated by the pair of bevel gears 93.
Inside the shaft of the members 92, is a hollow shaft 97, which rotates and controls the thread guide 98, the latter being capable of moving, under -the hub members 92, from a forward position to feed the needles A to a centripetally withdrawn position to cut ~23~3 them out, in the vicinity of an opening 100 for the retention and pneumatic suc-tion oE the thread F. A common device controls the radial motion of the additiorlal thread guide 98, at the beginniny and at the end of the stocking heel formation. The rota-tion of the shaft 97, in whose axial cavi-ty the yarn F passes, is control-led by the gears 99-101; gear 101 is integral with a small pinion 103, which in turn engages a cogwheel 105.
The latter is operated in one-way motion by a saw-toothed wheel 107 in combination with a pawl 109 (see Figure 1) mounted by means of a pivot 110 on a small lever 112 coaxial with the 105-107 system, which is appropriately braked by a hand brake 114. The small lever 112 is operated by a linkage 116-118 with a contact roller 120 operated by a cam 122, which is better illus-trated in Figure 6. This cam 122 has a rearming sector A, where the thread guide 98 is stationary, a sector B where the thread guide 98 moves at the same speed as the needle cylinder, a sector C where the thread guide 98 is caused to move at a speed approxi-mately three times greater than that of the needle cylinder 51, and a sector D where the thread guide moves at the same speed as the cylinder 51, all these movements, which are obtained by the cam 122 with the roller 120, are multiplied by means of the trans-mission device described above. Figures 4 and 5 show the opera-tion of the device described above. In Figure 4, PA shows the position in which the thread guide 98 remains stationary until all the working needles A have formed the loop in position PB. From point PA, the thread guide 98 moves to point PC while all 'he working needles A are lifted. Froln position PC the thread guide .

3l23~3 98 is caused to advance at a speed three times as high as that of cylinder 51 as far as posi.-tion PE, to move then to position PA at a speed equal to that of c~linder 51 and to stop there. At position PD th0 loop is formed with -the thread F previously placed against the needles A with the rapid motion of the thread guide 98.
A11 these operations -take place at each rotation of the needle cylinder 51. The needles A designed to worX in forming the heel of the stocking can be gradually cut out and included at the ends of the arc of working needles, to obtain the traditional formation of the heel, even with the continuous rotation of the cylinder 51 in the same direction and with alternating rows.
Figure 5 shows the position of the thread guide 98 when the loops must be formed with the thread F placed by the thread guide 98, which has moved beyond the needle cylinder 51 at three times its speed. Figure 5 shows the needles A lifted in the arc intended to form the heel starting with needle Ax; from this needle the thread F is placed in front of the needles A as the thread guide 98 moves beyond; simultaneously, in the manner described above, sector gear 63 starts operating, and therefore cam 61, so that the sinkers 59 are moved centripetally. During the forward motion of the cylin-der 51 after moving beyond cam 61 and when the latter has stopped gradually the sinkers 59 are moved in a centrifugal direction, that is, they are withdrawn to supply thread F sufficient for the ~ formation of the loops in the loop-forming position of the needles. In Figure 5, 59x shows the sinkers still advancing cen-tripetally, 59y the sinkers that are withdrawing, and 59z those that are cen-tri~ugally withdrawn.

Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A device for feeding yarn in stocking knitting and simi-lar machines for the formation of a heel pouch with continuous motion in the same direction of the needle cylinder and having an additional hollow thread guide which cyclically moves beyond the needles in an arc of needles to form heel of the stockings and places the thread in front of the lifted needles, which form with it chains of loops in the heel, said device comprising several additional sinkers, arranged in an arc concentric with said needle cylinder, a cam structure to operate said sinkers with the centri-petal forward motion and subsequent withdrawal, and an additional thread guide placed under a small platelike member.

2. A device according to claim 1, having a ring of tradi-tional sinkers provided with a downwardly projecting heel, and wherein said additional sinkers are positioned above said ring of traditional sinkers.

3. A device according to claim 2, including first and second coaxial sector gears each having a peg; a transmission pinion between and simultaneously engaging said first and second coaxial sector gears positioned on said ring of traditional sinkers; a stop rod for each of said sectors cooperating with said transmission pinion and movable to interfere with said peg on its associated sector for stopping thereof individually and to cause said cam structure to stop and move said sinkers therebeyond.

4. A device according to claim 1, wherein said thread guide is fed with yarn through an axially hollow shaft which operates said thread guide.

5. A device according to claim 2, wherein said thread guide is fed with yarn through an axially hollow shaft which operates said thread guide.

6. A device according to claim 4, including a pair of coax-ial sector gears each provided with pegs for operating said cam structure relative to said ring and said sinkers.

7. A device according to claim 3, wherein said thread guide is fed with yarn through an axially hollow shaft which operates said thread guide.

8. A device for feeding thread to stocking knitting machines and the like which form a heel pouch with continuous motion using a needle cylinder and an additional thread guide moving coaxially with said cylinder, said guide moving beyond the arc of needles of said cylinder to form the heel of said stockings by placing thread in front of the lifted needles in cooperation with a ring of first sinkers, said device comprising:
a plurality of additional sinkers arranged in an arc concen-tric with said needle cylinder and above said ring of first sink-ers;
a cam structure actuating said additional sinkers centri-petally and causing their subsequent withdrawal;
said cam structure constituting a housing for said additional sinkers;
a pair of coaxial sector gears driving said cam structure;
rod means for stopping both said sector gears and causing said cam structure to stop and said additional sinkers to move beyond said cam structure;
said additional sinkers being slidable relative to one of said sector gears in the direction of rotation of said needle cylinder to thereby cause said additional sinkers to withdraw centrifugally to yield thread and enable it to form subsequent loops for said heel pouch as said needles are lowered without applying excessive tension to said thread.

9. A device according to claim 8, further including means for accelerating said additional thread guide relative to said needle cylinder or to move at the same speed or to stop there-with.

10. A device according to claim 8, further including means for the retention and pneumatic suction of said thread.

11. A device according to claim 8, further including trans-mission means for controlling the radial motion of said additional thread guide at the beginning and at the end of the stocking heel formation, comprising:
a hollow shaft rotating and in which passes said thread;

gear means actuating said hollow shaft, a cam for operating said gear means one-way;
said cam including a sector where said guide is to be sta-tionary, a first sector where said guide is to move at substan-tially the same speed as said needle cylinder, a sector where said guide is to move at a speed substantially greater than said needle cylinder and a second sector where said thread guide is to move substantially at the same speed as said needle cylinder.

12. A device according to claim 11, wherein said cam has a sector where said guide is to move at a speed about three times faster than said needle cylinder.

13. A device according to claim 9, further including means for retention and pneumatic suction of said thread.

14. A device according to claim 13, further including trans-mission means for controlling the radial motion of said additional thread guide at the beginning and at the end of the stocking heel formation, comprising:
a hollow shaft rotating and in which passes said thread gear means actuating said hollow shaft;
a cam for operating said gear means one-way;
said cam including a sector where said guide is to be sta-tionary, a first sector where said guide is to move at substan-tially the same speed as said needle cylinder, a sector where said guide is to move at a speed substantially greater than said needle cylinder and a second section where said thread guide is to move substantially at the same speed of said needle cylinder.

15. A device according to claim 14, wherein said cam has a sector where said guide is to move at a speed about three times faster than said needle cylinder.