US2121652A - Take-up mechanism for sewing machines - Google Patents

Description

June 21, 1938. HfE. COOPER 2,

' TAKE-UP MECHANISM FOR sswme MACHINES Filed Jan. 25, 1937 luv 14 J62 6 Patented June 21, 1938 TAKE-UP MECHANISM FOR SEWING MACHINES Harold Edmund Cooper, Kettering, England, as-

signor to United Shoe Machinery Corporation, V a

Paterson, N. J., a corporation of New Jersey Application January 23, 1937, Serial No. 122,003

in Great Britain February 5, 1936 7 claims;

This invention is concerned with improvements in or relating to sewing machines and is particularly, but by no means exclusively, concerned with improvements in or modifications of rotary take-up mechanism of the kind described in U. 5. Letters Patent to Keall et al., No. 1,941,943, dated January 2, 1934, to Gouldbourn et al. No. 2,056,670 dated October 6, 1936, and to Gouldbourn et al. No. 2,049,369 dated July 23, 1935 which includes a thread engaging member moved during the machine cycle, at one time to pull the thread and at another time to give up thread, in a continuous closed path which is not a circle.

In a high speed machine constructed as disclosed in Patent No. 2,056,670 and modified as in Patent No. 2,049,369 and having a rotary takeup of the kind above referred to, the rotary takeup mechanism operates during the machine cycle to give up needle thread while a loop of needle thread is passing over the shuttle and then pulls the loop of needle thread passed over the shuttle down to lay the shuttle thread which it straddles on the Work and thereafter pulls the loop of needle thread into the work to set the stitch. During operation of such a machine there sometimes occurs breakage of the needle thread, particularlywhen a waxed needle thread is being used, near to the upper surface of the work and close to that portion of the loop of needle thread which actually engages the shuttle thread when the needle loop is pulled down, to set the stitch by the rotary take-up.

The more frequent breakage of waxed needle thread at this time in the operation of the machine is due, to some extent, to the fact that when thread has been waxed the thread becomes somewhat brittle and is therefore liable to break under a sudden strain and further, owing to the comparatively high speed at which the machine operates, to the fact that the rotary take-up pulls the loop of needle thread very rapidly down towards the work with the result that the sudden resistance offered by the work to the continued downward movement of the loop, after the shuttle thread has been laid upon the work, causes the needle thread to break.

One of the several objects of the present invention is to prevent, during the operation of a sewing machine having a rotary take-up mechanism of the kind referred to, breakage of needle thread from taking place in the manner aforesaid, as will hereinafter appear from the following description. The above and other objects are sought to be achieved in an illustrative embodiment of the invention by providing in the rotary take-up mechanism a yield which is effective at the time in the operation of the machine when the loop of needle thread is acting to pull the shuttle thread hard against the work just prior to the actual setting of the stitch, which yield then acts to minimize any snatch with which the loop of needle thread may be pulled downwardly by the take-up device due to the sudden resistance ofiered by the work to the continued downward movement of the needle loop. In its broader aspects, the invention is not limited to use with a continuously rotating take-up mechanism in a lockstitch sewing machine of the kind referred to, but is applicable for use with other forms of take-up mechanism and in other types of sewing machines.

In order that the nature of the present inven tion may become more clear, the illustrative embodiment aforementioned will now be described in connection with the accompanying drawing.

In the drawing:

Figure 1 shows in right side elevation a form of take-up embodying the present invention as applied to an outsole stitcher; and Figure 2 is a sectional view on the line 11-11 of Figure l.

The form of rotary take-up device illustrated in the drawing will be described as applied to a lockstitch outsole stitcher generally similar in operation to the machine described in the patents above referred to. This machine is provided with a curved hook needle 10, a lcoper l2, a thread lifter l4, a shuttle l6, a thread finger It, a Work support 20, and a presser-foot 22. In the illustrative embodiment there is rotary pinion 24 movable bodily in a circular path similar to that indicated at 69 in U. S. Patent No. 1,941,- 943, and a disc 26 similar to that indicated at in the latter patent. The pinion 24 and the disc 26 are, in the present illustrative embodiment not secured together in the manner disclosed in U. 5. Patent No. 1,941,943, but can move relatively about the rotary axis of the pinion 24 by reason of a yielding connection between the pinion and disc. The pinion 24 in the illustrative embodiment is secured on a hollow spindle 28'rotatably mounted in a casing 29, similar to that indicated at 61 in the patent last referred to, in place of the pin indicated at H in said patent. The hollow spindle 28 has formed on its right hand end, viewing the rotary take-up mechanism from the front of the machine, a head or block 39. The head 30 is substantially in the form of a rectangle with rounded ends, the head being about one quarter of an inch thick, about seven eighths of an inch in width, and about one inch and a quarter in length. The opposite sides of the head are bevelled off slightly to form faces as shown at 3|, 3| from the middle of the head towards its opposite ends so that the angle subtended between the opposite end portions of each side is some 175 degrees, the opposite ends of the head being therefore somewhat narrower than the middle portion.

The disc 26 of the present illustrative embodiment, which is the counterpart of that referred to as 15 in the latter patent carriesa thread engaging take-up roll 32 mounted eccentrically to the spindle 28 similar to the roll indicated at ll in said patent and has extending from the centre of one side face of it a pin 34 which enters into a hollow of spindle 28 with 7 freedom for rotary movement therein. Formed in the side of the face of the disc 26 from which the pin projects (1. e., the side nearer the said head) is a recess which receives the aforesaid head 30 on the hollow spindle 28, the width of the recess being equal to that of the widest part of the head on the hollow spindle. recess 36 in the disc is rectangular and the pin 34 which projects from the disc passes through the mid-portion of the recess. As will have been seen in Figure l, the end portions at the opposite sides of the head on the aforesaid hollow spindle 28 are so bevelled off that a small amount, about five degrees, of relative rotary movement may take place about the axis of the hollow spindle 28 between the head 30 on the hollow spindle and the disc 26 in which is the recess and which carries the take-up roll 32, the amount of rotary movement being limited between two positions by contact of the opposite bevelled end portions of the head with the opposite sides of the recess. Due to the eccentricity of the roll 32 to the spindle 28, rotary movement between the spindle and disc causes the roll to move bodily relatively to the rotary axis of pinion 24, the amount of thread taken up by the roll being changed correspondingly. The pin 34 is prevented from endwise movement in the hollow spindle 28 by a pin 38 passing laterally through the hollow spindle and through a recess 40 in the pin 34, which recess allows the relative rotary movement between'the pin and spindle to take place.

To enable the take-up roll 32 to exert a yielding pull on the thread, the head 30 on the hollow spindle has formed in it, at right angles to its length, a closed bore which receives a compression spring 42. The spring 42 presses against one side of the recess 35 in the disc 26 and tends to hold the disc at one end of its rotary movement relatively to the head and therefore to hold the take-up roll in a normally fixed position relatively to the hollow spindle.

The construction of the illustrative embodiment has for convenience been described in connection with a rotary take-up mechanism like that described in U. S. Patent No. 1,941,943, but it will be understood that the illustrative embodiment may equally well be used in the similar rotary take-up mechanism described in Patent No. 2,056,670 and its operation will now be described in relation to a machine and take-up mechanism as described in said. latter patent, in which the thread handling and work feeding instrumentalities (except in so far as the thread handling instrumentalities are modified in the manner disclosed in Patent No. 2,049,369) operate at the approximate times in the machine cycle described with reference to the diagram The shown in Figure 50 of thedrawing of said Patent No. 2,056,670.

During the time in the cycle of the machine indicated by the dot-and-dash lines A in Figure 1 of the accompanying drawing during which the take-up roll 32 is moving downwardly, as shown in Figure 3 of the drawing of Patent No. 2,056,670 in which figure the take-up rotates in aclockwise direction, and is drawing the loop of needle thread which has been passed over the shuttle down towards the work, preparatory to the setting of the stitch, i.- e., during the movement of the take-up from about 280 degrees to about 350 degrees in the diagram shown in said Figure 50, the take-up roll 32 occupies a position more rearward in the machine than the axis of the disc 26 which carries the roll and while, during this time, the take-up rotates in a clockwise direction, the take-up roll 32 is, besides being carried bodily round by the take-up mechanism, being rotated in a clockwise direction about the axis of the disc, i, e., it is being carried towards the forward side of the axis of the disc. During this part of the movement of the take-up roll the spring 52 in the head 30 on the hollow spindle is inoperative and merely holds the disc carrying the take-up roll at the limit of its counterclockwise movement about the axis of the said spindle, its angular position relatively to the spindle being then determined by contact between one of the bevelled faces 3i on the head 30 of the spindle and one side of they recess 35 in the disc 26 which carries the take-up roll. The arrangement is such that any resistance then ofiered by the thread to the movement of the take-up roll during this part of the movement of the take-up roll tends to move the take-up roll in a counter-clockwise direction about the axis of the disc and to hold the said bevelled face on the head more firmly against the side of the recess with the result that the loop of needle thread is pulled positively down towards the work. p

At the time when the take-up roll has just pulled the loop of needle thread down and laid the shuttle thread on the work which occurs at about 350 degrees of rotation of the main shaft of the machine from its initial position, the takeup roll 32 will havebeen advanced downwardly and forwardly both by bodily movement of the pinion 2% as the take-up mechanism rotates and by movement of the roll 32 about the axis of the disc 26 which carries'the roll into a position in which upward pressure exerted on the roll, due to the resistance ofiered to movement of the roll by the tensioned thread, tends to move the take-.

up roll in a clockwise direction about the axis of the said hollow spindle 28. The resistance of the loop of thread to downward movement of the take-up roll tends, by the consequent upward reaction exerted on the roll, at this time, to cause the disc 25 carrying the roll 32 to move in a clockwise direction about the axis of the hollow spindle 28 against the action of the spring 42 which normally urges the disc in a counterclockwise direction aboutsaid spindle. The extent to which the disc can so move angularly about the axis of the spindle is limited by contact of another of the bevelled'faces 3! on the spindle head 30 with a side of the recess 36 in the disc 26 and, as before indicated, is approximately some five degrees. .During such movement of the disc relatively to the spindle, the take-up roll, which as before stated will then lie at the forward side of the axis of the spindle; will rise slightly (e. g.,

some of an inch) towards the work out of the path, indicated at D, it would otherwise follow and thus relieves to a small, but nevertheless measurable, extent the tension exerted on the thread at this time. Thus during a part of the movement of the take-up roll when the'roll is acting to set the stitch which part extends from between about 350 degrees to 10 degrees in the diagram, providing the machine makes more than a complete cycle, the roll 32 can yield to relieve any sudden tension on the thread against the action of the spring in the head on thehollow spindle. Before the roll reaches the position, indicated by the full lines B in Figure 1, in which it actually completes the setting of the stitch, however, the yield between the disc and spindle will normally have been completely taken up so that in completing the stitch setting the roll pulls positively on the thread. After the stitch has been set and the take-up mechanism continues to rotate, the take-up roll gives up needle thread to the thread handling instrumentalities and during this thread giving-up part of the movement of the take-up roll, indicated by'the dot-and-dash lines C in Figure 1, such strain as was imposed on the thread during the major portion of setting of the stitch is relieved and, if the take-up roll has yielded against the action of the spring 42 in the head on the hollow spindle, the spring once more rotates the disc carrying the roll in a counterclockwise direction about the spindle and returns the roll to its original position relatively tothe spindle.

There is thus provided a yielding means in the take-up mechanism which is inoperative during the greater portion of the pulling down of the loop of needle thread after the loop has been passed over the shuttle but may become automatically operative substantially at the time when the loop lays the shuttle thread' firmly against the work and during the setting of the stitch,

which yielding means may then yield and thus tend to prevent undue strain on and consequent breakage of the needle thread and in which, at a time when setting of the stitch is being completed, the yield will normally have been taken up so that the stitch is finally set by a positive pull on the needle loop by the take-up roll.

The nature and scope of the invention having been indicated, and a form of the invention having been described, what is claimed is:

1. A lockstitch shoe sewing machine having, in combination with the other stitch forming devices, a take-up comprising a thread engaging member, and mechanism for actuating the thread engaging member to pull the needle loop from the shuttle into the work and to set the stitch comprising yielding means rendered inoperative while the thread engaging member is pulling the needle loop from the shuttle and rendered operative as each stitch is being set to relieve sudden tension on the thread.

2. A lockstitch shoe sewing machine having, in combination with the other stitch forming devices, a take-up comprising a thread engaging member, and mechanism for actuating the thread engaging member to pull the needle loop into the work and to set the stitch including a spring for causing the thread engaging member to exert a yielding pull on the needle thread, and means for limiting the yielding pull exerted by the spring to insure that the stitch will finally be set with a positive pull.

3. A shoe sewing machine having, in combination with the other stitch forming devices. a take up comprising a rotary member arranged to move bodily in a circular path, a thread engaging member mounted eccentrically to the axis of rotation on the rotating member, and yielding means acting on the thread engaging member to permit a limited bodily movement of the thread engaging member about the axis of rotation of the rotary member under the pull exerted on the thread during the setting of a stitch.

4. A shoe sewing machine having, in combination with the other stitch forming devices, a takeup comprising a rotary member arranged to move bodily in a circular path, a thread engaging member mounted eccentrically on said rotary member, and means for rotating said rotary member comprising a yielding connection permitting a limited rotary movement of said member under the pull exerted on the thread during the setting of a stitch.

5. A shoe sewing machine having, in combination with the other stitch forming devices, a take-up comprising a rotary driving member arranged to move bodily in a circular path, a thread engaging member mounted eccentrically to the axis of rotation on the rotary driving member, and a yielding connection for causing the thread engaging member to exert a positive pull on the needle thread while the resistance ofiered by the thread tends to move the thread engaging member in one direction about the axis of rotation of the rotary member, and to exert a yielding pull on the needle thread while the resistance offered by the thread tends tomove the thread engaging member in the other direction.

6. A shoe sewing machine having, in combination with the other stitch forming devices, a takeup comprising a rotary driving member arranged to move bodily in a circular path, a thread engaging member, a spindle concentric with the rotary member on which the thread engaging member is eccentrically mounted for bodily movement relatively to the rotary member, means for limiting the bodily movement of the thread engaging member between two positions about the spindle relatively to the rotary member, the resistance oifered by the thread tending to hold the thread engaging member in one position while the take-up pulls the needle loop towards the work and in the other position while the takeup sets the stitch, and spring means for holding the thread engaging member in the position assumed while the take-up pulls the needle loop towards the work.

'7. A shoe sewing machine having, in combination with the other stitch forming devices, a take-up, comprising a rotary driving member arranged to move bodily in a circular path, a thread engaging member eccentric to the axis of rotation of the rotary member, a spindle connected to the rotary member, a block on the spindle formed with an end narrower than another portion thereof, a supporting disc for the thread engaging member formed with a recess loosely surrounding the block, the width of said recess being substantially equal to the widest part of the block to permit the disc to pivot about the widest part of the block between positions determined by engagement of the end of the block with the sides of the recess, and spring means acting between the block and the disk to hold the thread engaging member yieldingly in position relatively to the rotary member.

HAROLD EDMUND COOPER.

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