US2680365A - Fabric take-up device and method of maintaining tension on fabric - Google Patents

Description

June 8, 1954 51', PlERRE 2,680,365

FABRIC TAKE-UP DEVICE AND METHOD OF MAINTAINING TENSION ON FABRIC Filed Aug. 28, 1952 I 4 I I EUGENE STE/E225;

Patented June 8, 1954 FABRIC TAKE-UP DEVICE AND METHOD OF MAINTAINING TENSION ON FABRIC Eugene St. Pierre, Pawtucket, R. I., assignor to Hemphill Company, Pawtucket, R. I., a corporation of Massachusetts Application August 28, 1952, Serial No. 306,882

7 Claims.

This invention relates to a new and useful improvement in fabric take-ups for circular independent needle knitting machines.

It is well known that, for most types of knitting performed on a machine of this type, it is desirable to apply a certain amount of tension to the knitted fabric to assist in the positive casting off of the loops from the needles and in the correct formation of the loops themselves. The commonest and most usual type is a weight applied to the knitted fabric by hand and removed and re-applied whenever necessary. Other and more nearly automatic types, which are also in more or less common use, are called fabric take-ups. These consist of two or more resiliently engaging rolls between which the fabric can pass, the rolls being turned intermittently by one or more pawls and ratchets.

Neither of these types is satisfactory for the knitting of extra length hosiery such as ladies hosiery, or for such hosiery when the highest possible quality is the objective. The length of ladies hosiery is so great that the welt will reach the floor before the toe is finished. Consequently, if a weight is used as a tensioning device, the tension on the fabric will be lost unless it is repositioned during the knitting of the stocking, which involves the stoppage of the machine. This, alone, is likely to cause one or more courses which differ in loop structure from the others, and fastening the weight to intermediate parts of the stocking is also likely to damage the fabric. Nevertheless, the only tensioning device known to be in use at present is the welt weight. To compensate for the length of ladies stockings and to avoid repositioning the weight, machines are supported upon platforms of sufficient height above the fioor to cause the stocking with weight attached to clear the floor. Such platforms are inconvenient and dangerous.

The ratchet type take-up is also unsatisfactory for sheer hosiery of high quality because of the intermittent character of its motion. This produces a variation in tension between some courses and others which is also detectable in the fabric as rings of different loop formation.

The take-up of this invention utilizes the steady unvarying tension of a weight and maintains it above the floor, thus making possible the use of the most desirable type of tension without its previous limitations.

One form of the device is shown in the drawing, of which:

Figure 1 is a side elevation illustrating one characteristic operating position; and

Figure 2 is a similar side elevation in less detail, illustrating another characteristic operating position.

As shown in Fig. 1, the device consists of a roll I freely turnable upon its shaft la. The shaft at each end is flattened and the flattened ends are mounted in a slide 2 formed by plates 3 and 4 and corresponding plates at the other end of the roll.

There is also a take-up roll 5 and another roll 5 mounted on an arm which is pivoted so that roll 8 will be maintained in engagement with roll 5 through the pull of spring I. Roll 5 is ratcheted around in an intermittent manner by means of a ratchet 8 attached to the roll, and pawl 9, the pawl being mounted on a rockable holder 59 in such a manner that, when holder I0 is rocked, the pawl will turn the ratchet. To eifect this rocking, a rod II is attached to the projecting ear I2 of pawl holder It). The lower end of this rod. engages an eye l3 attached to rocker it which is pivoted at I5. One end of rocker I 4 is provided with roller I6 engageable with a fixed circular cam H by means of which rocker It can be rocked in a vertical plane. The rocking of rocker I4 will cause rod I I to reciprocate and this, in turn, will rock pawl holder I0 and cause pawl 53 to operate ratchet 8 and turn roll 5.

This mechanism is mounted below the lower end of the cylinder of the knitting machine and is rotatable therewith,.if the machine is of the usual rotatable cylinder type.

The fabric I8 is led from the cylinder (not shown), down and around roll I and up and between rolls 5 and 6. Therefore, when rolls 5 and 6 are being turned through the agency of cam H, as described above, the fabric will be taken up. The relation between cam I1 and the operating mechanism of rolls 5 and 6 is such that the rate of take-up will be somewhat greater than the rate of feed of the fabric from the cylinder. Therefore, as rolls 5 or 6 turn, the shortening of the fabric loop will gradually raise roll I from its lowermost position, shown in Fig.

1, to the higher position, shown in Fig. 2. Roll I is freely rotatable and freely suspended in both of these positions so that the tension placed by it upon the loop of fabric which surrounds it is uniform at all times.

When roll i has reached its lowermost operating position, assumed to be that of Fig. 1, the time has come for reducing the length of the loop of fabric by which it is suspended. This i accomplished by the operation of take-up rolls 5 and 6,

as explained above. Although these rolls work in the intermittent manner characteristic of all pawl and ratchet devices, this intermittent movement is not transmitted to the fabric under tension of roll I.

On the flattened end I9 of the shaft la is mounted a vertically extending rod 20, the upper end 2| of which overlies end 22 of bellcrank 23. Below the other end 24 of bellcrank 23, a pivoted latch 25 is connected to end 24 of bellcrank 23 by a spring 28 in such a manner as to swing to the right or left of dead center as end 2A of bellcrank 23 is similarly swung. Rod 29 is also provided with a pin '27 engageable with'the underside of end 22 of bellcrank 23. As the length of the fabric loop around roll I is reduced, roll I will move upward until pin 2! engages end 22 of bellcrank 23. Further upward movement causes pin 2? to swing end 22 upward and end 25 to the left. This will move spring 25 off dead center and cause latch 25 to engage adjustable shoulder 22 of rocker id, as shown in Fig. 2. This engagement occurs when roll I6 is at, or approximately at, the high point of cam ll so that, as long as latch 25 remains in engagement with shoulder 23, rocker I4 can not move sufficiently to operate rolls and 8. Therefore, the taking up of fabric by these rolls ceases.

The continued production of knitted fabric will gradually lengthen the fabric loop around roll l. Therefore, roll I will gradually move down. This movement continues until end 2! of rod 29 engages end 22 of bellcranl: 223 and thereafter swings it downwardly with the result that end 25 of bellcrank 23 is swung to the right. This moves spring 2601f dead center in the other direction and latch 25will be disengaged from shoulder 28, leaving rocker I4 free to operate rolls 5 and 5 again to reduce the length of the fabric loop.

In this way, a steady unvarying weight is applied to the knitted fabric as it is produced but, unlike present practice, the movement of the weight is confined within narrow limits well above the floor. volved, thebad effect on fabric of this type of motion. is eliminated because it hasno effect upon the application of tension to the fabric. The device is compact and, with the exception of cam H, is self-contained so that it is applicable to almost any standard type of circular knitting machine.

The gauge of the fabric being knitted and other factors may alter the amount. of tension which should be applied to the fabric on roll I. This may be provided for by substituting rolls of different weights or by so constructing roll I that its interior is hollow and accessible so that weights may be inserted into, or removed from, its hollow interior to obtain the desired overall weight. If desired, these weights may be in the form of washers suspendable from the shaft of the roll. Rolls 1, 5 and 5 are, of course, of sufiicient length to receive the knitted fabric in the proper way.

I claim:

1. A method of maintaining uniform tension on fabric drawn from a source into a take-up which comprises providing a loop in said fabric between said source and said take-up, inserting a tensioning member in said loop, commencin the operation of said take-up when said loop exceeds a predetermined maximum length, and ceasing the operation of said take-up when said loop reaches a pits-determined minimum length.

2. A method, of maintainingconstant tension upon; fabric being -knit ona circular :knittin rma- Although a pawland ratchet is in-.

chine which comprises forming in said fabric a loop and feeding said fabric to a fabric take-up, inserting a weighted member into said loop, operatin said fabric take-up after the length of said p reaches a given maximum amount to take up the fabric at a rate faster than said fabric is knit so that the length of said loop is reduced, and ceasin the operation of said take-up when the length of said loop reaches a given minimum amount so that a constant tension is maintained by said weighted member upon said fabric as it is knit.

3. For a circular knitting machine having a cylinder adevice for maintaining constant during knitting the amount of tension upon the fabric being knit which comprises a fabric take-up, a weighted memberv adapted to ride in a loop of said fabric between said cylinder and said takeup and means controlled by said member for startin the operation of said take-up to take up said fabric when said loop-is longer than a" given lengthand for stopping the operation ofsaid take-up when the length of said loop has been lessened to the desired amount.

4. A fabric take-up device for a circular, independent needle, knitting machine which comprises a pair of rollers adapted to draw knitted fabric therebetween, means for turning said rollers so as to draw said fabric, a tensioning member adapted to maintain tension on said fabric being drawn by said rollers, and means operated by said member for starting and stopping operation of said means for turning said rollers.

5. A fabric take-up device for a circular, independent needle, knitting machine having a cylinder which comprises a pair of rollers adapted to draw knitted fabric therebetween, a ratchet adapted to turn said rollers, cam actuated means adapted to drive said ratchet, a member adapted to respond to the length of fabric between said cylinder and said rollers, and means controlled by the response of said member to said length of fabric whereby the operation of said cam actu- 7 ated means is controlled.

6. A fabric take-up device for a circular knitting machine which comprises a pair of fabric drawing rollers, ratchet means for drivin said rollers, cam actuated means for driving said ratchet means, a latch for controlling the operation of said cam actuated means, a freely turnable roller movable with relation to said fabric drawing rollers, and means operated by said roller for operating said latch.

7. A fabric take-up device for a circular, independent needle, knitting machine which comprises a pair of rollers adapted to be turned with relation to each other so as to draw fabric between them, a free running roller situated below and movable in relation to said rollers, means for turnin said pair of rollers, and means controlled by said movable roller for controlling the operation of said means for turning.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 557,845 Manderfield et al. Apr. 7, 1896 623,539 Gulich Apr. 25, 1899 668,568 Wilcomb Feb. 19, 1901 1,506,153 Berdon Aug. 26, 1924 1,755,809 Buraux et al Apr.22, 1930 2,586,470 Lawson Feb. 19, 2,645,106 Lambach July 14, 1953

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