US3003342A

US3003342A - Fabric tensioning devices for knitting machines

Info

Publication number: US3003342A
Application number: US606024A
Authority: US
Inventors: Kent Alfred Woodward; Bentley Percival Arthur
Original assignee: Bentley Engineering Co Ltd
Current assignee: Bentley Engineering Co Ltd
Priority date: 1956-08-24
Filing date: 1956-08-24
Publication date: 1961-10-10
Anticipated expiration: 1978-10-10

Description

Oct. 10, 1961 A. w. KENT ETAL FABRIC FENSIONING DEVICES FOR KNITTING MACHINES 5 Sheets-Sheet 1 Filed Aug. 24, 1956 I l N I venloU K.\f

/ ttorney Oct. 10, 1961 A. w. KENT ETAL 3,003,342

FABRIC TENSIONING DEVICES FOR KNITTING MACHINES 5 Sheets-Sheet 2 Filed Aug. 24, 1956 Oct. 10, 1961 A. w. KENT ETAL 3,003,342

FABRIC TENSIONING DEVICES FOR KNITTING MACHINES Filed Aug. 24, 1956 v 5 Sheets-Sheet 5 Oct. 10, 1961 A. w. KENT EIAL 3,003,342

FABRIC TENSIONING DEVICES FOR KNITTING MACHINES Filed Aug. 24, 1956 5 Sheets-Sheet 4 y al 5% Aiicrney Oct. 10, 1961 A. w. KENT EI'AL 3,003,342

FABRIC mzsxonmc DEVICES FOR KNITTING MACHINES 5 Sheets-Sheet 5 Filed Aug. 24, 1956 1M m w I. mk A 1. 27

Patented Oct. 10, 1961 3,003,342 FABRIC TENSIONING DEVICES FOR KNITTING MACHINES Alfred Woodward Kent and Percival Arthur Bentley,

Leicester, England, assignors to The Bentley Engineering Company Limited, Leicester, England Filed Aug. 24, 1956, Ser. No. 606,024 12 Claims. (Cl. 66-150) This invention is for improvements in or relating to fabric tensioning devices for knitting machines and while particularly applicable to circular knitting machines is not necessarily restricted to use therewith as it may be adapted to use with straight bar knitting machines.

In the knitting of ladies hose, and particularly in cases in which fabric of sheer appearance is required, it is found desirable that the knitted fabric shall be subjected to a certain amount of tension on withdrawal from the needles, which tension is found beneficial in producing the best and most uniform fabric having a regular loop formation. In cases in which articles are knitted separately from one another on knitting machines requiring a fresh setting up course as each article is commenced the application of tension to the fabric as it passes from the needles introduces a difiicult problem as the normal tension or take-up mechanism is placed at such a distance from the needles as to be incapable of engaging the fabric until a substantial length thereof has been formed. The problem arises particularly in the case of circular machines for knitting ladies hose with inturned welts as during the formation of the welt the fabric extends from welt hooks to the needles in double formation and tends to bunch up and become difiicult to control.

The invention has for one of its objects to provide a fabric tension device by which take-up tensions can be applied readily to a short portion of knitted fabric on leaving the needles.

In accordance with the invention there is provided a tensioning device comprising a plurality of fabric engaging members disposed in proximity to the needle circle or line in position to engage with fabric on its way from the needles and means for oscillating said members to cause them to engage the fabric and apply withdrawal tension thereto. The tension members are preferably spaced uniformly apart along the needle circle or line and may be caused to oscillate in unison or in two or more groups at different times.

Preferably the members are arranged in pairs, those in each pair being alongside one another and being oscillated in succession.

In a preferred construction the fabric engaging members are arrangedfor oscillation each around a closed path so as to urge it towards the fabric, then away from the needles, then away from the fabric and back toward the needles.

An important provision of the invention is a fabric tension device for use with a circular knitting machine having a plurality of movable members for engaging the fabric arranged immediately within the nwdle circle and spaced apart uniformly therearound, and cam means for oscillating said members to cause them to engage and apply tension to the fabric immediately the latter leaves the needles.

In circular machines for knitting inturned welts in which pressing off occurs after each hose, control of the welt during its formation or'the first part of its formation may be obtained by means of a welt presser which engages the fabric between the welt hooks and the needles. The tension mechanism in accordance with the invention may with advantage be employed in such a machine with the tension members serving to engage the fabric and apply tension thereto while it is being engaged by the welt presser as well as when more fabric has been made than the welt presser can control.

In a preferred arrangement the invention contemplates an assembly for insertion in a needle cylinder in the throat end thereof comprising a mounting for a plurality of fabric engaging tension members and cam means associated with the latter to cause the tension members to be moved in guides in said mounting, first inwardly, then downwardly and afterwards outwardly and upwardly.

The engagement of tension members as aforesaid with the fabric may be secured by providing the members with bristles of hair, wire, nylon, or other substances or with strips of natural or artificial fur or of rubber or any other substance providing frictional or similar gripping engagement with the fabric. A particularly effective arrangement is one in which bristles are set at an inclination to direct them partly towards the fabric and partly away from the needle line.

A preferred embodiment of the invention from which an understanding of its manner of use may be obtained is illustrated in the accompanying drawings and will now be described by way of example with reference to the drawings in which:

FIGURE 1 shows a section of the knitting head of such a machine with the work tension device in position;

FIGURE 2 shows a plan of the cylinder, sinker cam ring etc. but with the welt dial unit removed;

FIGURE 3 shows a sectional plan at about the line AA of FIG. 1

FIGURES 4 and 5 show a pair of work tension members;

FIGURE 6 shows the cage in which these members are carried;

FIGURE 7 shows a development of the operating cams;

FIGURE 8 shows a plan view of the upper row of cams;

FIGURE 9 shows a plan view of the lower row of cams;

FIGURES l0 and 11 show the action of the welt presser;

FIGURES 12, 13, 14, and 15 show various stages in the operating movement of one of the work tension members, and

FIGURE 16 is a part sectional plan corresponding to FIGURE 3 but illustrating a modification.

As shown in FIG. 1 the cylinder 1, knitting cams indicated generally at 2, inturned welt mechanism and sinker unit are all of substantially normal type, one departure from standard being the provision of a key 3 and keyway 4 in the inner sinker ring 5. Two forms of slender, arcuate,'work tension members, are employed and are shown respectively in FIGS. 4 and 5. One pair consisting of one of each is located in each of a plurality of slots 61: of cage 6, FIG. 6, 7 being the leading one and 8 being the rear one. The cage 6 has an upper ring 60 which fits inside the inner sinker ring 5 and is keyed to it so as to receive with it the keyway 6a engaging the key 3. In circular knitting it revolves in the direction of arrow 9, (FIGURE 6).

The fabric engaging mediums in this example are tufts of bristles 7a and 8a projecting from the top and inner faces of the

members

7 and 8. They project inward from the upper edge and downward from the inner vertical edge of each member. The

members

7 and 8 can slide in the slots 6b in cage 6 and are controlled by earns, the leading members 7 by the upper row of cams shown in FIG. 7, and the rear ones 8 by the lower row of cams. These cams are made from rings of T-section, and each

member

7 and 8 has a T-shaped slot 7b or 8b in which the cams operate. The cams are so shaped as to give both up and down and in and out movements to the

members

7 and 8, and are carried in a cylindrical casing formed by

easing sections

10, 11 and 12, (FIG/8), which in turn are secured to the upper end of a tube 13 (FIGS. 1 and 3). The

casing sections

10, 11 and 12 are formed with an internal circumferential groove 44 presented between internal flanges teenga'ge rotatably with a peripheral rib 45 formed. on the cage '6 so as to support the cams and locate them heightwise.

The "lower end or tube 13 has a bearing in ball race earner just below this a cut of tooth 13A which is engaged by pawl 15 to prevent the cams from rotating aiiticlockwisew'ith the

members

7 and 8. The latter thus move along the cams and take their up and down andin and out movements from them. The pawl 15 is urged into engagement with the tooth 13A of tube 13 by spring 16, and is fulcrumed on pin 17 fixed in segment 18. This is secured to the underside of bed plate 19', by screws passing through slots in segment 18. The slotsenable the tube 13 and the operating cam tobe timed angularly with respect to the knitting cams so as to obtain the best operating position.

The action of the

members

7 and 8 will now be described in more detail. r

The leading members 7 are operated by the upper row of cams shown in plan in FIG. 8 and move through a series of positionsshown in FIGS. 12, 13, 14 and 15. In FIG. 12 one of the members 7 is shown in a low withdrawn position as it could be when engaged by the portion 19a of cam 1). It rises next up the slope 19b to the position in FIG 13 and stays thus along cam 20,

segments

21 and 22 and cam 23. When it reaches cam 24 it advances inward and descends slightly as shown in FIG. 14, the angle of movement conforming generallyto the slope of welt presser 25 and the underneath slope 26 of the inturned'welt dial (see FIGS. and 11).. This movement, due to cam 24, is timed to occur at the point where the sinkers 26 knock over the loops in the knitting operation and a fresh course of fabric is being delivered inward. from the needles, and also occurs below the nose 25A of welt presser 25. The bristles of the upward portion of member 7 engage the fabric and pull it inward as 'Finally the members encounter the outward-leading cam 28 and are withdrawn from the fabric totheir out-ofaction position as shown in FIG. 12, when again they rise up cam 19b to the top position.

1 The rear members 8 have a similar action due to the cams shown in FIG. 9 but they operate at different times relative to the members 7 They rise up cam 29' as the leading members 7 come forward along cam 24, so as toengage the fabric and maintain it in the position at tained by members 7 Then they in turn come inward and descend alightly upon cam 36, stay thus upon cam 31 and descend to their lowermost position upon cam 32, staying thus upon the

segments

33 and 34 and cam 35 garment, the welt presser is withdrawn clear of the needles, as in the position shown in d otted lines in FIG. 2. At the start of a hose, after "the previous one has been pressed ofi, the yarn is re-intr'oduced and after one or two cbursesthe dial jacks are advanced in normal manner to receive loops, which thus extend from them to the needles. The welt presser isthen released by aetu'a tion from the control d'r'u'r'n presses upon these to take the newly inane fabric 40 inward towards the fabric

e aging members

7 and 8 as shown in FIG. 1,

so formin'gtwo layers of fabric, the u per one being attached to the books of the dial iacks the lowerone extending and moving course by course from-the needles. The 'welt presser 25 moves inward till its nose 25A is above the highest art or members 7 nds, that is to the positionsh'own in full lines in FIG. 2, by which time the

members

7 and 8 tan engage with the lower layer of fabric and assist its movement from the needles. I Due to the intervention of the Welt resser nose 2 5A between the two la ers of fabric the bristle'sat the upper ends of and are withdrawn from the fabric by cam 36. Thus there is always one of each pair of

members

7 and 8 with its upper end engaging the fabric while each member assists the passage of the fabric through the constricted diameter of thecage.

The'segments 21 and 22 in the upper row'of cams,

the fabric engaging members act effectively on the lower fabric layer without acting on the upper layer thereby pulling the lower layer gently inward and downward and preventing it from bunching up beneath the dial. This eliminates any tendency to'loop distortion and the making of ""cross feet" irregularities. In FIG. 1 the welt is shown partly made, the lower layer tending to cling to the bristles of the fabric engaging members and to travel down throughthe cage. I e p I When the welt is completedth'e held loops or! the "dial jacks are transferred to the needles and the

fabric engaging members

7 and 8 continue to operate for the leg portion of the hose, helpingthe fabric away from the needles and putting upon it a light tension, sufiicient to ensure clear and uniform loop formation. It is found advantageous to withdraw the welt presser 25 a little way after the Welt has been completed, to the position shown in chain dotted lines in FIG. 2, to facilitate subsequent operations such as round splicing when threads must float across the inside of the hose. The fabric engaging members continue to function on the fabric throughout the circularly knitted portion of the hose,

In the heel and toe the welt presser is withdrawn to the dotted line position, and the cylinder of the machine oscillates. On the backward movement ofthe cylinder the pawl 15 (FIG. 3) will not of course hold the tube 13 stationary and hence the tube moves with the cylinder, there being no relative movement between the

fabric engaging members

7 and 8 and their operating cams so that they do not operate during the backward stroke, but only during the forward stroke of the cylinder. When the heel is completed the welt presser goesback into action, to the chain dotted line position, and the

fabric engaging members

7 and 8 operate throughout the foot of the hose. a

The welt presser 25'can be temporarily withdrawn for any required purpose such as a yarn change, if necessary, without causing any loss of effect of the

fabric engaging members

7 and 8, as once th'esehaveengaged the fabric, and particularly when it is going down through the inside of the cage 6, the fabric remains in'contact with them whether the welt presser is in action or not.

FIGURE l6 'shows an alternative type of pawl to prevent rotation of the tube 13 and cams for operating the fabric engaging members; -In this modification the tube 13. has a slot 131) formed with angular faces 13c and 13d slanted in relation to radii of the tube, and the pawl indicated at 42 has its nose of corresponding form to fit in the slot 13b, being urged into engagement therewith by spring 43. The latter is of such strength as to hold the pawl in the slot 13b against normal running torque but if for any reason the operating mechanism for the

fabric engaging members

7 and 8 should tend to jam the spring will yield and allow an angular face of slot 13b to cam the pawl out of action so that the fabric tensioning device will revolve or oscillate as a whole with the needle cylinder to avoid damage. In normal running this modified pawl arrangement causes the device to operate as previously described for rotational knitting, but when the machine goes into oscillatory knitting in forming heels and toes the fabric engaging members have normal oscillating movement during the forward stroke of the needle cylinder and also operate in the reverse direction to their normal stroke during the backward stroke of the cylinder. Due to the inclination of the bristles 7a and 8a it is found that even when the

members

7 and 8 are operated in a direction opposite to the normal one they still tend to urge the fabric away from the needles.

In the example shown, two forms of fabric engaging members are used, but if desired only one form may be provided and caused to operate substantially as do the leading members 7 in the example illustrated. Each one in that case may be in a separate slot in a suitable cage. Alternatively more than two forms may be used and caused to operate in sequence. Means other than cams may be used for the operation of the fabric engaging members. The fabric engaging members may have inserted bristles or may be made of mouldings incorporating them. Particularly as only one form of fabric engaging member is needed, means may be provided to hinder the fabric from moving back when the fabric engaging members are released from it, such as a series of inwardly and downwardlyprojecting bristles projecting from the cage itself, and not receiving any movement, such as are shown at 41 in FIG. 6.

Instead of bristles, strips of natural or artificial fur may be attached to the fabric engaging members, in such a way that the hairs of the fur point inward and downward as do the bristles shown in FIGS. 4 and 5. Alternatively natural or artificial strips of rubber may be used as fabric engaging mediums, which may have projections formed upon them to assist in promoting their hold upon the fabric. The fabric engaging members may operate each in turn or in groups or all at once, and may operate one or more than once in each course of knitting. On a multi-feed machine they may be made to operate at each knitting point, between the knitting points or both at and between the knitting points.

In the example shown the fabric engaging members move a fixed distance, it being found that the natural elasticity of the fabric and of the bristles of the fabric engaging members allows for any variations inthe amount of fabric made, as for example when the stitch length is changed. In some cases this may not be sufficient and for this purpose means of adjustment, for example cams having an adjustable throw, may be provided to vary the extent of movement of the fabric engaging members.

The details of construction may be varied Without departing from the scope of the invention.

What we claim is:

l. A fabric tensioning device for use with a knitting machine having a needle cylinder with a plurality of needles arranged to form a needle circle and comprising a plurality of slender arcuate fabric engaging members having fabric contacting elements disposed in proximity to the needle circle in position to engage a short portion of fabric on its way from the needles to apply withdrawal tension thereto, the fabric engaging members being mounted for positioning immediately within the needle circle and spaced apart therearound, a tubular cage adapted to be mounted within the needle cylinder and to be retained against rotation relative to said cylinder, said cage having guide slots to receive said fabric engaging members internally thereof and extending in the general direction of the axis of the cage, and cam means between which and the cage, relative rotation is arranged to occur during operation of the knitting machine, said cam means beingdisposed to act on the fabric engaging members to effect their oscillatory movements.

2. A device according to claim 1 wherein the cam means is arranged externally of the cage and portions of the fabric engaging members extend through the slots in the cage to co-operate with the cam means.

3. A device according to claim 1 for use with a rotary cylinder knitting machine and having the cam means coupled to a sleeve extending below the cylinder and co-operating with a pawl to determine the setting of the cam means circumferentially of the needle cylinder.

4. A device according to claim 3 wherein the said sleeve is held against rotation with the needle cylinder in the normal direction of rotary knitting by means of the said pawl and is permitted to rotate with the cylinder in the opposite direction.

5. A device according to claim 3 wherein the said sleeve is resiliently held by the pawl against rotation with the cage but is permitted to rotate with the cage if excessive stresses occur.

6. A device according to claim 1 wherein the cam means comprises cams of T-shaped cross section to engage in similarly shaped recesses associated with the fabric engaging members, said cams being arranged around the cage in a track having raised and lowered portions and inwardly and outwardly offset portions to provide for the oscillatory movements of the fabric engaging members.

7. A device according to claim 6 wherein each slot in the cage accommodates two fabric engaging members and the cam means comprises two sets of cams at different levels co-operating respectively with the two fabric engaging members in each slot of the cage and arranged to operate in timed sequence so that the fabric engaging members in each slot are operated at different times.

8. A, device according to claim 1 for use with a circular knitting machine having a welt presser and having the fabric engaging members arranged to present their upper portions towards the Welt presser and to engage with fabric extending from the needles against the adjacent face of the presser.

9. A device according to claim 1 wherein the interior of the cage is shaped to the general form of the throat of a needle cylinder and the fabric engaging members have their fabric engaging faces formed with upper substantially horizontal ends curving downwardly and inwardly to a substantially vertically extending lower portion past which the fabric is drawn from the needle cylinder.

10. A device according to claim 9 wherein each of the fabric engaging members is provided with surface irregularities to exert a pull on the fabric when in contact therewith.

11. A device according to claim 10 wherein the fabric engaging members are provided with tufts of bristles for engagement with the fabric.

12. A device according to claim 11 wherein the bristles are inclined to the surface of the fabric engaging members in the direction away from the position of the needle circle of the knitting machine.

References Cited in the file of this patent UNITED STATES PATENTS 408,272 Tifiany Aug. 6, 1889 801,930 Steber Oct. 17, 1905 808,784 Steber Jan. 2, 1906 1,981,919 Montague Nov. 27, 1934 2,017,082 Warren Oct. 15, 1935 2,345,698 Bromley et al. Apr. 4, 1944 FOREIGN PATENTS 223,282 Switzerland Nov. 16, 1942 533,059 Germany Sept. 8, 1931