US2529181A - Sinker cam mechanism for circular knitting machines and method of operating a circular knitting machine - Google Patents

Description

Nov. 7, 1950 529,181

F. R. PAGE 2, SINKER CAM MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHOD OF OPERATING A CIRCULAR KNITTING MACHINE Filed April 25, 1947 5 Sheets-Sheet 1 Nov. 7, 1950 F. R. PAGE 2,529,181

. SINKER CAM MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHOD OF OPERATING A CIRCULAR KNITTING MACHINE Filed April 25, 1947 3 Sheets-Sheet 2 T F- C 306 fnven'z'ar FRANK R. PAGE 2 his ai-Z-arne yi Nov. 7, 1950 F. R. PAGE 2,529,181

SINKER CAM MECHANISM FOR CIRCULAR KNITTING MACHINES AND METHOD OF OPERATING A CIRCULAR KNITTING MACHINE Filed April 25, 1947 3 Sheets-Sheet 3 In-ueniar FRANK R. PAGE Q hzLs'aZZ-arnqya MMJM Patented Nov. 7, 1950 SINKER CAM MECHANISM FOR CIRCULAR KNITTING' MACHINES AND METHOD OF OPERATING A CIRCULAR KNITTING MA- CHINE Frank R. Page, Laconia, N. H., assignor to Scott- & Williams, Incorporated, Laconia, N. IL, a corporation of Massachusetts Application April 25, 1947, Serial No. 743,870

9 Claims. (61.66-108) This invention relates to sinker cam mechanism for circular knitting machines and more particularly to machines adapted to make finegauge hosiery. In modern hosiery for ladies it is necessary to make time stitches, and yet at certain parts of the stocking such as the makeup and picot it is necessary to have stitches which are considerably slacker than the tight stitches. It is known to box in the sinkers at the knocking-over point on circular knitting machines in order to produce small stitches, but no satisfactory way has heretofore been evolved for making uniform stitches and at the same time obtaining accurate casting off of slack stitches. I have discovered how this can be accomplished, and it is characteristic of my invention that the sinkers are boxed in at the castoff point and that when making slack stitches the sinkers are holding the fabric down at an auxiliary point by resilient pressure. This is accomplished by the use of two cast-off cams, the first being a fixed one with the sinkers controlled by an adjustable boxing-in or landing cam, and the second .or auxiliary cast-off cam located at a point shortly after the regular castoff point being pressed radially inward by spring pressure. It is also characteristic of my invention when used for certain purposes that the spring pressure is varied at different parts of the knitting of a stocking.

In the drawings:

Figure l is a perspective view of the essential parts of the mechanism for exerting spring pressure on the auxiliary cast-off cam;

Figure 2 is a plan-view of the outer sinker cap of a machine made in accordance with my invention, showing the cams which operate on the sinkers as they near the knocking-over point;

Figure 3 is a side elevation of a needle and sinker in the machine of Figs. 1 and 2, showing the sinker, needle and stitch relation at the regular sinker cast-off point when the sinker is controlled by a combination of the regular cast-off cam and boxing-in cams, in accordance with my invention;

Figure 4 is a view similar to Fig. 3 showing the relation of the needle and sinker of Fig. 3 with the yarn omitted;

Figure 5 is a View similar'to Fig; 3 but showing the sinker inserted to full depth by the auxiliary sinker cam to cast off a loose stitch;

Figure 6 is a view similar to Fig. 3 showinga loose stitch when there is no auxiliary cast-off cam;

sinkers of Fig. 7 with the cam surfaces in dotted lines; while M Figure 9 is a diagrammatic view in elevation of the knitting cams at the knocking-over point of the embodiment of Figs. 1 to 8.

The ordinary modern circular hosiery machine with independent needles N and sinkers 292 for making hosiery contains a circle of sinkers acting as webholders which" are actuated by cams in the usual outside sinker cap 300. The sinkers face inwardly and have nebs 290 above knocking-over ledges 29L These sinkers are adapted to assist in holding down newly-drawn stitches while the needles N are rising after passing under the point of the stitch cam 360 (Fig. 9). Ordinarily the insertion of the sinkers at the knocking-over point comes to its maximum at the line marked A in Fig. 9, the position of this maximum insertion also being indicated with relation to the sinker wave in Fig. 8. This insertion is ordinarily caused by what is known as the cast-01f cam, which I will hereinafter designate as the regular cast-off cam 308. The sinkers are driven in by it until they exert pressure on the newly-formed loops. However, I have found that it is impossible to control all sizes and types of stitches properly by this one cam 308 when knitting a complete fine-gauge stocking. When the regular cast-off cam is used alone the sinkers are free to continue their inward movement until they hit the fabric. When the sinkers are operated in this manner they fire inward and help to cast off the loose stitches. On the other hand, their action may be irregular and, furthermore, is much affected by the speed of the machine. Thus at high speed a slacker fabric is knit than at a low speed. This is particularly noticeable when the machine slows down just before changing into the heel. At this point one or more very tight courses occur and there may even be cutting of the yarn due to the tightness of the stitches. To get uniform stitches regardless of the speed of the machine, I box the sinkers in at the regular sinker cast-off point A. The end or tip 3l0 of the regular center sinker cam 3|2 therefore is made pivoted and is held in adjusted position by a screw 3 to box in the sinker butts so they cannot drive in. It acts as a landing cam. On the other hand, it is extremely difficult with the sinkers boxed in to hold the stitches down for casting off during the make-up courses and the 492 onthe latch ring post (not shown) I have also found it possible by using spring pressure at the auxiliary sinker cast-off point C, in distinction to the boxed-in arrangement at the regular sinker cast-off point A, to vary the pressure at point C in accordance with the needs of the various parts of the stocking. Thus, .for example, too great a pressure on the auxiliary sinker cast-off cam will cause cutting of the yarns in the make-up, but considerable pressure is necessary on the auxiliary cam when casting'off tuck stitches used in making a picot. Some pressure is also'desirable in the rest of the welt. I

therefore not only provide means for putting ,spring pressure on the auxiliary sinker cast-off cam when needed, but also make such pressure variable.

The mechanism for controlling the auxiliary sinker cast-off cam in this manner is controlled from the main pattern drum by means of drum cams SM, 502, 503 which, respectively, are

shown as high, medium and low drum cams (Fig. 1). They are all in the same path on the drum and serve to move a thrust bar 431. v This thrust bar can be used to actuate the latch closing ring (not shown), all as set forth in the patent to Robert W. Scott No. 1,238,052, dated August 21, 1917, for Yarn Feeding Mechanism for Knitting Machines. The upper end of the thrust bar is connected to the lower arm of a bell crank lever 493 which oscillates about a stud The upper arm of the bell crank lever is connected to a wire 618 going to the latch closing ring above mentioned. The control of the auxiliary sinker cast-ofi cam 309 is obtained from the upper arm of the bell crank lever 493 as follows. There is the usual tension spring 414 attached between the upper arm of the bell crank lever 493 and the latch ring 55.0 to press the upper arm against the means operating the auxiliary cast-off cam 309. Mounted on the bedplate B of the machine is a post 324 which supports a vertical rod 325 by means of two lugs 323 forming part of the post.

'On the upper end of the rod is fastened an arm 32'! lying in the path of the upper arm of the bell crank lever 493. The lower the thrust rod, the more the bell crank lever pushes against the arm 32-? and turns the vertical rod 325. The rotation of the vertical rod 325 is transmitted to the auxiliary sinker cast-off cam 309 by means of a sinker slackening lever 328j attached to the rod 325 and a leaf'spring 329 on that lever. As can be seen in Fig. 1, the lever crosses under the upper of the two lugs 32 3, and the leaf spring 329 lies just outside the auxiliary cast-off cam 309. There is a tension spring 330 tending .to turn the lever 328 away from the auxiliary cam 309 against the pressure of tension spring 4'54. The angle of the arm 32% and the spring 329 is such that the spring is out of contact with the auxiliary cast-off cam, except when the thrust rod is on the low drum cam 503 or directly on the 4 the tension spring 330 attached to the vertical rod 325. This operates against the drum cams 502, 503. When it is on a low pattern drum cam 503, it exerts a moderate amount of pressure against the cam, such as is suitable for use during the makeup. When the, thrust rod is lowered to the surface of the pattern drum the rod 325 is turned further by the bell crank lever 493 and the pressure is increased to that necessary for the picot cast-01f. It will be noted that the high drum cam 50| serves to actuate the latch opening ring and that this actuation occurs at a time which does not interfere with the insertions of the auxiliary sinker cast-off cam.

With the arrangement described it will be seen that the sinkers are positioned accurately at the regular cast-off point and that their overthrow is prevented by the boxed-in cams. At the same time the arrangement of the parts is such that the sinkers press inwardly by spring pressure at the auxiliary cast-01f point when stitches are being made which require greater pressurefor casting off than canlbe obtained from the boxedin cams.

In this way the diificulties of both boxed-in cams-and of the spring-pressed regular sinker cam are avoided. The tight line across the in step of the stocking that, tends tov be formed by the lack of overthrow of the sinkers when the machine is slowed down prior to starting the heel or at any other time when: the machine is slowed down or stopped, is eliminated. Also, vertical streaks caused by uneven tightness of the sinkers in their slots are avoided. On the other hand, all the stitches are cast off clean.

The operation of the machine will now be described. Assuming that the machine is about to commence the manufacture of a stocking beginning from the bare needles, the parts will be pattern drum itself. The leaf spring 329 is held away from the auxiliary cast-off cam 309 by in the position of Fig. 1. Then the pattern. drum is racked to bring a low drum cam 503 under the thrust rod 46!. When the thrust rod drops onto this low cam, the bell crank lever 493 pushes the arm 32'! against the tension spring 330 so as to bring the leaf spring.329 against the auxiliary.

cast-off cam 309 with light. pressure. Thislight pressurev by the sinkerslackening cam 328 and the leaf spring 329 is maintained during the make-up courses. It. insures that the sinker nebs 290 get over the stitches and hold them down. At the commencement of. the welt the pattern drum is racked again until the'thrust rod drops down onto the surface of the pattern drum I20 itself; This causes the sinker slack;- ening lever 328 to put heavy pressure on the auxiliary sinker cam during the welt. This insures that there is sufficient pressure to cast off the picot tuck stitches in the welt. The position of a sinker is shown in Fig. 5. This full pressure against the sinkers at the auxiliary cast-off line C is relieved as soon as the welt has been completed and the knitting of the stitches in the leg begins. For this purpose the main pattern drum is racked to bring av medium drum cam 502 under the thrust rod. Thereupon the tension spring 330 swings the leaf spring 329 away from the auxiliary sinker cast-off cam to the position shown-in Fig. 1. In this figure the pattern drum I20 has been turned fromits position during the leg in order to show the drum cams. The thrust rod is at the same elevation as during the leg, although actually during the leg it would be resting on the other drum, cam marked 502. The parts normally stay in thi's position throughout the knitting of the leg, the

drum being racked forward to bring a high drum cam 50l under the thrust rod during the reciprocatory knitting of the heel and toe. However, under certain conditions it has been found advantageous to have the thrust rod 46! rest on a cam of the height equal to drum cam 503 during the making of the leg and foot. This results in the auxiliary cam 309 exerting a light pressure on the stitches after they have been cast off in the leg and gives an evening effect to the stitches. It is during the heel and toe that the gap closing ring is brought into operation. It will be observed that there is no necessity for extra pressure on the sinker at this time in order to obtain proper casting off. It will also beobserved that while the amount of projection of the sinkers at the auxiliary point C is limited by the fabric, the projection at the regular point A is determined by the cams in the raceway.

What I claim is:

1. In a circular knitting machine having independent latch needles and sinkers, control means for the sinkers comprising a cam at the cast-01f point to press the sinkers in and an adjustable cam opposite it boxing the sinkers in at that point to prevent overthrow, in combination with a movable secondary cast-01f cam following and spaced from the cast-off point to push all the sinkers in an extra depth, and resilient means adapted to press the secondary cam inwardly, for the purpose described.

2. In a circular knitting machine having independent latch needles and sinkers, control means for the sinkers comprising a cam at the cast-off point to press the sinkers in and an adjustable cam opposite it boxing the sinkers in at that point to prevent overthrow, and a movable secondary cast-off cam following and spaced from the cast-off point, in combination with a spring adapted to press the secondary cam inwardly and control mechanism for the spring adapted to vary the pressure on the secondary cast-off cam according to the stitch being knit.

3. In a circular knitting machine according to claim 2, a pattern drum and cams of different heights on said drum, in combination with levers from said pattern drum to said spring adapted to vary the pressure of the spring on the secondary cast-0E cam in accordance with the heights of the drum cams.

4. In a circular knitting machine according to claim 3, the adjustment of the levers such that with one height of drum cam, pressure of the spring on the secondary cast-oif cam is entirely relieved.

5. In a circular knitting machine having independent latch needles and a series of sinkers, a stationary center landing cam adjusted to limit sinkers at the cast-off point to give uniform movement, and a cast-off cam pressing the butts of sinkers against that landing cam, in combi- 6 nation with a movable secondary cast-off cam following and spaced from the cast-ofi point adapted to move sinkers further toward the center of the machine than permitted at the cast-- off point, and spring means pressing this secondary cast-off cam inwardly against the sinkers.

6. In a method of operating a circular knitting machine having independent latch needles and sinkers, the steps of guiding the sinkers in a boxed-in path at the sinker cast-01f point so as to prevent overthrow, in combination with the step of pushing the sinkers radially inward under resilient pressure at a point shortly after the castoff point to hold down stitches.

7. In a method according to claim 6 of operating a circular knitting machine having independent latch needles, sinkers, a landing cam and a regular cast-off cam, the step of holding down tight stitches at the cast-off point by means of the landing cam and regular cast-off cam, in combination with the step of exerting spring pressure at a point following the cast-off point to hold down slacker stitches by spring pressure.

8. A method of operating a circular knitting machine to make a stocking containing an inturned welt started with make-up stitches and an ankle containing tight stitches, comprising the step of guiding sinkers in a boxed-in path at the cast-off point to prevent varying pressure against the tight stitches, in combination with the step of pushing the sinkers inward under resilient pressure against the make-up stitches at a point shortly after the cast-off point to hold down said make-up stitches.

9. A method of operating a circular knitting machine to make a stocking containing a picot formed with tuck stitches and an ankle containing tight stitches, comprising the step of guiding the sinkers in a boxed-in path at thecast-off point to prevent varying pressure against the tight stitches, in combination with the step of pushing the sinkers inward under firm spring pressure at a point shortly after the cast-01f point to cast off said tuck stitches.

FRANK R. PAGE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,641,554 Scott Sept. 6, 1927 2,063,026 Bristow Dec. 8, 1936 2,142,693 Lawson et al Jan. 3, 1939 2,200,207 Page et a1. May 7, 1940 2,337,153 Cloutier Dec. 21, 1943 FOREIGN PATENTS Number Country Date 221,686 Great Britain Sept. 18, 1924

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