US3469421A - Yarn take-up mechanism for straight bar knitting machines - Google Patents

Description

P 0, 1969 o. A. COZENS 3,469,421

YARN TAKE-UP MECHANISM FOR STRAIGHT BAR KNITTING MACHINES Filed March 27, 1967 5 Sheets-Sheet l Sept. 30, 1969 D, A, cozENs 3,469,421

YARN TAKE-UP MECHANISM FOR STRAIGHT BAR KNITTING MACHINES Filed March 27. 1967 5 Sheets-Sheet 2 p 30, 1969 D. A. COZENS 3,469,421

YARN TAKE-UP MECHANISM FOR STRAIGHT BAR KNITTING MACHINES Filed March 27. 1967 5 Sheets-Sheet 3 Sept. 30, 1969 D. A. COZENS YARN TAKE-UP MECHANISM FOR STRAIGHT BAR KNITTING MACHINES Filed March 27. 1967 5 Sheets-Sheet 4- P 0, 1969 o. A. COZENS 3,469,421

YARN TAKE-UP MECHANISM FOR STRAIGHT BAR KNITTING MACHINES Filed March 27. 19s? s Sheets-Sheet 5 United States Patent YARN TAKE-UP MECHANISM FOR STRAIGHT BAR KNITTING MACHINES Dennis Alan Cozens, Loughborough, England, assignor to William Cotton Limited Filed Mar. 27, 1967, Ser. No. 626,142

Claims priority, application Great Britain, Apr. 16, 1966,

16,767/ 66 Int. Cl. D04b 15/52 U.S. Cl. 66-129 4 Claims ABSTRACT OF THE DISCLOSURE Yarn take up mechanism for a straight bar knitting machine in which a pair of horizontal yarn gripper plates, between which yarn extends horizontally, are mounted on a first cam operated slide to have varied horizontal movements, and for the opening and closing of the gripper plates having a second cam operated slide arranged for horizontal movements and having inclined slot and pin connections with a stationary member to provide raising and lowering movements which are imparted to the upper gripper plate relative to the lower gripper plate.

This invention is for improvements in or relating to straight bar knitting machines and concerns yarn take-up mechanism.

The conventional yarn take-up mechanism known as snapping tackle comprises a rigid arm on a cam-rotatable rod and a spring arm superimposed on the rigid arm and secured at one end to the root end of the rigid arm and at its other free end overlying a fixed rod with the yarn extending between the two arms. During the draw, the rotatable rod holds the rigid arm in a down position so that the spring arm is held by the fixed rod deflected upwardly from the rigid rod and the yarn is thereby allowed to run freely through the device. During the knitting cycle, the rotatable rod is in an up position in which it lifts the spring arm clear of the fixed rod so that the yarn is gripped between the two arms and the rotatable rod has a motion to raise and lower the two arms together thereby to raise and lower the yarn to follow the knitting motions of the needles; this maintains constant tension in the yarn i.e. without undue tightness or slackness. The passage of the yarn to the snapper is in substantially horizontal direction and its passage from the snapper is downwardly. At the end of the knitting cycle and before starting of the next draw the rotatable rod lowers the arms to separate them for free running of the yarn during the draw. The fact that this free running of the yarn is downwards from the snapper leads to a slackening of the yarn. It is further to be noted that the earlier raising of the two arms in closed position has to be to a comparatively considerable extent to follow the needle raising movements so that the amount of slack formed by the arms subsequently lowering is also comparatively considerable. In general this is not a serious matter since this slack is taken up by the thread carrier during an early part of the next draw. When knitting intarsia fabric a number of thread carriers operate over a limited number of needles and this leads at least at certain times to such a short traverse of thread carriers that at least some of the slack is not taken up. This again is not necessarily a disadvantage in instances where the joints between the different fabric areas are formed by overlap of complete inter-knitted loops. However when special sinkers with undercut front edges are employed for deflecting yarn at the fabric joints downwardly, so that the joints are not formed by overlap of complete inter-knitted loops but are merely formed by overlapping "ice parts of loops, the fact of the yarn being slack, and particularly being slack to considerable extent, leads to the yarn riding over the sinkers instead of being deflected downwardly by the front edges of the sinkers and faulty joints occur.

It might be thought that the slack could be avoided by providing some means to hold the spring up at an elevated level so that the yarn would be free while the rigid arm descends, but it is found that by virtue of the bend in the yarn it becomes slack when the rigid arm lowers whether or not the spring arm traps or frees the yarn.

There are other instances in connection with straight bar knitting machines generally, such as at selvedges and in fashioning courses, where it is desired to provide more accurate control of the yarn than is possible by the conventional snapper mechanism because of its characteristic construction.

An object of the invention is to provide yarn take-up mechanism which is of such improved construction that it can be operated to provide, for example, for the avoidance of the slack above referred to when making the special fabric joints for intarsia fabric.

The invention provides straight bar knitting machine yarn take-up mechanism comprising, a pair of superimposed yarn engageable members to, from and be tween which the passage of yarn from a supply to a thread carrier can be in a straight path, means coupling the members together for joint displacements in directions longitudinally of the yarn, means mounting the members for relative displacements therebetween in directions transversely of the yarn for gripping or releasing the yarn, and means for effecting the displacements in such corelated manner as to provide for running of the yarn either freely, or controlled to any suitable extent, at any suitable times.

By this means, yarn can be caused at any time to have any required degree of tightness and slackness, and to be free running or otherwise at will, so that for example when making fabric joints for intarsia fabric, by the special method hereinbefore referred to, the aforesaid slack in the yarn can be avoided. It is also apparent that in many other instances the yarn can be caused to be in required conditions more accuartely than heretofore.

Conveniently a first of the yarn engageable members is mounted on a first slide member adapted for displacements longitudinally of the yarn, a second of the yarn engageable members is adapted for like movements with the first yarn engageable member by being mounted on a rod projecting transversely from the first slide member, and the second yarn engageable member is adapted for displacements transversely of the yarn by being spring biased against a second slide member which is adapted for displacements longitudinally of the yarn and is. also connected by a pin and inclined slot connection to a. stationary member so that the longitudinal movements are converted to transverse movements. Conveniently the spring is also arranged to bias the second yarn engageable member in a direction towards the first yarn engaging member. Conveniently also the first yarn engageable member is disposed at the underside of a horizontally extending part of the yarn with the second yarn engageable member at the upper side of the yarn. Conveniently also the transverse rod extends from the first slide member through holes in both yorn engageable members, and a transverse hole is provided in the transverse rod for passage of the yarn therethrough. The second slide member is conveniently composed of opposite side parts, and the spring biased second yarn engageable member is of upturned channel form with its underside edges riding on the sides of said slide. The first and second slide members are connected by link and lever mechanism to separate cam followers engaging separate cams.

The invention also provides straight bar knitting machine take-up mechanism wherein upper and lower yarn gripper plates are spring biased together and are applied to a horizontally running part of the yarn, the lower plate member is secured on a cam operated horizontally displaceable upper slide member for joint displacements of the plate members horizontally and longitudinally of the yarn, and the upper plate member has depending side walls riding on side parts of a cam operated horizontally displaceable lower slide member which has pin and inclined slot connection with a stationary member to convert the latters horizontal motion to a vertical motion of the upper plate member, so that the plate members alternatively grip or release the yarn at any required stage in relation to the horizontal displacements, whereby accurate control of the yarn is readily obtainable when required in substantially unlimited manner.

The above and other features of the invention set out in the appended claims are incorporated in the construction which will now be described, as a specific embodiment, with reference to the accompanying drawings, in which:

FIGURE 1 is a general cross sectional view of part of a straight bar knitting machine embodying yarn takeup mechanism according to the invention.

FIGURE 2 is a side view of the yarn take-up mechanism.

FIGURE 3 is a perspective view of the yarn take-up mechanism.

FIGURE 4 is a longitudinal sectional view of the mechanism.

FIGURES 5 is a cross sectional view of the mechanism.

FIGURE 6 is an enlarged face view of part of intarsia fabric made with special sinkers.

FIGURE 7 is a perspective view of part of the sinker bar showing the special sinkers.

FIGURE 8 is an enlarged side view showing one of the special sinkers.

FIGURE 9 is a front view of needles, sinkers, thread carrier and yarn at one stage in the production of the intarsia fabric.

FIGURE 10 is an enlarged view of part of FIGURE 1.

Referring to FIGURE 1 a straight bar knitting machine is represented by bearded needles 1 operated by usual cam operated mechanism 2, usual sinkers or dividers 3 mounted in the usual sinker bed 4 on a machine rail 5 and usual thread carrier bars 6 mounting thread carriers such as the thread carrier indicated at 7. On a second machine rail 8 is mounted a support frame 9 for a yarn package 10, and for eyelet yarn guides 11 to 11d by which the yarn Y is guided from the yarn package 10 to the thread carrier 7 including in a horizontal path indicated at Y1. At the trailing end of the yarn along the path Y1, there is a cymbal yarn tensioner 12.

The yarn in the yarn path Y1 extends through a yarn take-up device indicated generally at 13, FIGURES 1 and 10.

This device comprises a stationary base support 14 on which is mounted a pair of yarn engaging members 15, 16.

More specifically, with particular reference to FIG- URE 4, the yarn engaging member 15 is a strip metal member having a horizontal portion 15a disposed directly at the underside of the yarn Y, and it is bent at its ends to provide portions 15b, 150 which are secured to a slide member 17, and also to provide eyelet yarn guides 18, 18a through which the yarn extends.

The slide member 17 mounts an upstanding peg 19 which extends through a hole in the portion 15a of the yarn engaging member 15 and also through a hole in the yarn engaging member 16. The latter is of upturned channel form comprising a horizontal portion 161:, disposed over the yarn Y, and downwardly depending side walls 16b, 160, see FIGURE 5, on the opposite sides of the yarn Y, the yarn engaging member 15, and the slide member 17. On the peg 19 is a coil spring 20 disposed between the yarn engaging member 16 and a collar 21 on the peg thereby to bias the yarn engaging member 16 downwardly towards the yarn Y and towards the yarn engaging member 15.

The peg 19 has a transverse hole 190, FIGURE 4, for the yarn Y to extend therethrough.

For guiding the slide member 17 screw nuts 22, 22a secured to its underside co-operate with a slot 23 in a bar 24, see FIGURES 4 and 5, which is secured by bolts 26, FIGURE 4, to the stationary member 14.

The side walls 161), of the yarn engaging member 16 have lower out-turned flanges 16d, 16c, FIGURE 5, which ride on upper horizontal edges of opposite side slide parts 27, 27a. These slide parts 27, 27a are connected to the stationary member 14 by pins 28, 28a, FIGURES 1, 10 and 2, secured to the stationary member 14, and cooperating inclined slots 29, 29a formed in the slide parts 27, 27a. The slide member 17 is connected by a link 30 to an arm 31, FIGURE 1, on a rod 31a which also has an arm 31b connected by a link 32 to a cam follower lever 33 having a cam follower 34 engaging a cam 35 on the main cam shaft 36.

The side slide parts 27, 27a are connected by a link 37 to an arm 38 on a rod 38a which also has an arm 38b connected by a link 39 to a cam follower lever 40 having a cam follower 41 engaging a cam 42 on the main cam shaft 36.

The cams 35, 42 have rises and falls to suit requirements of operations of the yarn engaging members 15, 16, it being understood that operation of cam 35 will cause displacements of the slide member 17, and consequently of the yarn engaging members 15, 16 longitudinally of the yarn Y and that operation of the cam 42 will cause longitudinal displacements of the side slide parts 27, 27a which, through the pin and inclined slot connections, will cause the slide parts 27, 27a to be raised or lowered thereby to raise or lower the yarn engaging member 16 towards and away from the yarn Y and from the yarn engaging member 15. The upward movement of the yarn engaging member 16, i.e. away from the yarn and yarn engaging member 15, is positive against the action of the spring 20, and the lowering of the yarn engaging member 16 into engagement with the yarn Y is by the spring 20.

It will be understood that with the yarn engaging member 16 in the lowered position it grips the yarn Y to the yarn engaging member 15 so that upon longitudinal movement of the slide member 17 in either direction, the yarn will be carried with it. On the other hand when the yarn engaging member 16 is in the upper position the yarn Y is free running.

It is also important to note that with the yarn engaging member 16 in the upper position, the yarn engaging members 15, 16 can be carried by the slide member 17 in a direction longitudinally of the yarn without carrying the yarn with it. Consequently it is possible by providing suitable rises and falls on the cams, to provide for any required condition in the yarn, i.e. as regards degree of tightness, slackness, and free running or otherwise to suit any particular requirements at any time.

For example considering the making, by the machine, of intarsia fabric illustrated in FIGURE 6, it will be seen that this fabric is characterized by having, at the joint A between two fabric areas B and C, overlapping open loops L of yarn which are not complete knitted loops.

This construction is formed by the use of special sinkers indicated at 3a, FIGURE 7, which have undercut front edges 3b, and alternate with dividers 3.

One of these special sinkers 3a is indicated enlarged in FIGURE 8 in relation to the normal type sinker or divider 3, needle 1, and thread carriers 7.

FIGURE 9 illustrates a front view of FIGURE 8 showing a plurality of the sinkers and needles with one thread carrier 7.

This thread carrier 7 in FIGURE 9 is shown at a stage where yarn is taken around a needle for the joint A in FIGURE 6.

The arrangement is such that in order to produce the open loop connections L of FIGURE 6 without forming the yarn into complete knitted loops, the yarn must be defiected downwardly by the undercut front edge 3b of the adjacent sinker 3a. However when the conventional snapping tackle is employed, as hereinbefore explained, the yarn Y is caused by necessary operation of the snapping tackle to become slack, and this has led to the yarn riding over the tops of the undercut front edges 3b of the sinkers 3a as indicated by the yarn Y shown in broken lines in FIGURE 9.

On the other hand by use of the yarn take-up mechanism as above particularly described, the necessary movement of the yarn engageable members 15, 16 in a direction from right to left can be effected with the cam 42 operating on the side slide parts 27, 27a to hold the yarn engaging member 16 in its up position clear of the yarn so that the yarn is not carried with the yarn engaging members and consequently no slack is formed. Under these circumstances the yarn is satisfactorily engaged by the undercut front edges 3b of the sinkers 3a and satisfactory joints are made in the intarsia fabric.

During the draw it is required for the yarn to be free running through the take-up mechanism and at this stage the cam 42 would again hold the yarn engaging member 16 clear of the yarn. During the knitting cycle it is necessary for the yarn to he carried towards and away from the thread carrier in order to follow the knitting movements of the needles, and for this purpose the cam 42 would operate to hold the yarn engaging member 16 in its low gripping position for the yarn while the cam 35 is operated to displace the slide member 17 and consequently the yarn engaging members 15 and 16 in opposite directions in synchronism with the movements of the needles.

There are other instances such for example as when making fabric selvedges, and when fashioning, when it is required to have accurate control of the yarn, or free running of the yarn, and it will be understood how by simply providing the necessary rises and falls on the earns 35 and 42, any required condition in the yarn can be obtained to suit the particular requirements at necessary times.

What I claim is:

1. In a straight bar knitting machine having a thread carrier, mounting means for a yarn package, and means guiding yarn in part of its passage from a yarn package to the thread carrier to extend in a straight path, a yarn gripper device mounted in said straight path and comprising a first plate extending over said straight path and a second plate extending under said straight path, mounting means for said first and second plates allowing for opening and closing movements thereof and joint displacements thereof longitudinally of said straight path, a first operating mechanism connected to said first plate for imparting to the latter its opening and closing movement, a second Operating mechanism connected to said second plate for imparting to the latter and said first plate their displacements longitudinally of said straight path, and co-related cams connected to said first and second operating mechanisms respectively for effecting at required different times, required combinations of the yarn gripper device being open, closed, and displaced in yarn feed and reverse directions.

2. Mechanism as claimed in claim 1 wherein said mounting means includes a peg extending freely through said second plate and freely mounting said first plate, with spring means on said peg biasing said first plate towards said second plate.

3. Mechanism as claimed in claim 1 wherein said mounting means includes a support, a first slide on said support and on which said first plate is slidably mounted, spring means by which said first plate is biased against said first slide, a second slide secured to said second plate, peg and inclined slot means attaching said first slide to said support for sliding motion of said first slide in one direction to cause opening of said first plate from said second plate and in the return direction to allow said spring means to close said first plate onto said second plate, and connecting means connecting said first and second cam operated mechanisms to said first and second slides.

4. Mechanism as claimed in claim 1 wherein said mounting means includes a first slide on which said first plate is slidably mounted, and a second slide to which said second plate is secured, said first slide comprising two parts on opposite-sides of said second slide, said first plate being of inverted U form having side walls slidable on said two parts of said first slide, and means connecting said first and second cam operating means to said two parts of said first slide and to said second slide respectively.

References Cited UNITED STATES PATENTS 1,238,716 8/1917 Scott 66-146 2,309,026 1/1943 Thost 66146 2,899,811 8/1959 Start et a1. 66-126 FOREIGN PATENTS 771,757 4/1957 Great Britain.

ROBERT R. MACKEY, Primary Examiner US. Cl. X.R. 66-126, 132, 146

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