US2248347A - Locking thread case for sewing machines - Google Patents

Description

July 8, 194% I o, s I 2248,34?

LOCKING THREAD CASE FOR SEWING MACHINES Filed May 20', 1-939 121 entow W W www 8 WitneSs-MJM 4 20 2 Patented July 8, 1941 LOCKING THREAD CASE FOR SEWING MACHINES Otto R. Haas, North Beverly, Mass., assignor to United Shoe Machinery Corporation, Borough of Flemington, N. J., a corporation of New Jersey Application May 20, 1939, Serial No. 274,674

14 Claims. (Cl. 112-38) The present invention relates to improvements in a locking thread supply case for a wax thread sewing machine, employing a shuttle of the rotary or oscillatory type for passing loops'of needle thread about the thread case, an example of which is disclosed in U. S. Letters Patent to Gouldbourn et al. No. 1,991,456 dated February 19, 1935.

The locking thread case in the machine of the patent is removed from the shuttle when renewing the thread supply and is of generally hollow cylindrical shape, the inner end being open and the front outer end closed. When introducing a fresh thread supply, the end of thread is inserted through small guide eyes, one at-either side of a tension device in the circular side wall of the thread case for directing the thread from within the thread case through the circular side wall to the tension, and from the tension axially of the thread case along the circular wall-to the outer surface of the front end Wall before reaching the work, in order to prevent thread leading from the thread case to the work from being caught by the beak of the shuttle which surrounds the circular wall of the thread case. The thread case in this type ofv machine ismaintained by heating devices at a wax melting temperature which renders it uncomfortable to handle when removed from the machine so that it is the practice to wrap the thread case in a cloth or wad of, waste while threading. As a result, the guide eyes may be blocked by the cloth surrounding the thread case. In continued. use of the machine the problem of replenishing the supply of locking thread, therefore, is a matter of irritation and difficulty on the part of the operator.

The objects of the present invention are to simplify and improve theconstruction of a looking thread supply case for a machine of the type referred to in order to facilitate the operation of rethreading the thread case when inserting a fresh supply of thread.

With these and other objects in view, the present invention contemplates the provision in a cylindrical locking thread case having one end open to receive a supply of locking threadand a yielding thread tension in a circular side wall thereof, of an arrangement including quick threading guide eyes at opposite sides of the tension device to direct the thread respectively through the circular wall of the thread case'to the tension and from the tension towards the.-

work. In the present embodiment ofthisfeature of the invention the quick threading guide eye "the thread case and the thread guide eye.

for directing the thread through the circular wall of the thread case comprises a slot entering the open end of the thread case, and the quick threading eye at the other side of the tension directs the thread through a perforated lug extending radially beyond the circular wall at the closed end of the thread case beyond the path of the loop taker beak.

The tension of the thread case in the patented machine is effected by a wire spring bent to follow the curvature of the circular thread case wall. To enable the spring to act properly in the prior machine, the spring is located on the circular thread case wallbetween the open end of According to a further feature of the present invention, the tension spring is arranged at a location which will permit access to the thread guide throughthe open end of the thread case without shortening the spring or rendering it less efiective to regulate the tension.

The front closed Wall of the thread case in the machine of the above mentioned patent has formed in it a groove engaged loosely by a thread case rotation limiting and retaining member, and

the thread case, it passes between the retaining,

member and the'front thread case wall, the retaining member forcing, the thread in the needle loop towards. the bottom of the groove. In the 1 construction hereinafter illustrated, the thread entering slot which permits. quickthreading of the thread in the lug is formed along the bottom of the groove which receives the retaining member so that there isno danger from engagement of the needle loop with the threading slot.

These and other objects of the invention including certain details of construction and combinations of parts will be further explained in the following description, taken in connection with the accompanying drawing and pointed out in the appended claims. In the drawing Figure 1 is a view in right hand side elevation of the front portion of a machine embodying the features of the present invention; Figure 2213 a perspective View showing the closed front end wall and a portion of the side wall of the thread case employed in the machine; Figure 3 is a'perspective view of the thread case showing the open inner end; Figures 4 and 5 are views in elevation partly in' section lookingat the closed end wall of the thread case and indicating successive steps of the threading operation; Figure 6 is a sectional detail view, taken along the line 6-6 of Figure and Figure '7 is a developed view of the circular side wall of the thread case.

The invention is illustrated as applied to a locking thread supply case similar to that disclosed in the patent to Gouldbourn et a1. above identified. That machine is a waxed thread outso-le shoe sewing machine, and is provided with stitch-forming devices including a curved hook needle Ill, a continuously rotating discoidal shuttle l2, and a cylindrical thread case M removably and rotatably supported within the shuttle. Within the thread case i is mounted a supply of locking thread Iii in the form of a bobbin or thread cop and from the supply the thread passes through the circular wall of the thread case past the .tension device and axially of the thread case through a guide eye formed in 2. lug, as indicated at it, extending radially beyond the circular side wall of the thread case from the closed front end wall.

The tension device of the illustrated machine comprises a block shaped member 29 slidable axially of the thread case in a suitably formed guideway on the circular side wall, and at one side the block is. notched to receive the free end of a circumferential bar spring 22 surrounding more than 180 degrees of the outer surface along the circular thread case wall. To prevent escape of the spring 22 axially, the circular wall of the thread lease is grooved so that the wall thickness is reduced about its central portion to provide shoulders 24 and 26. The shoulder 24. supports the spring 22 and is formed with a recess 28 to receive a fulcrum lug 38 extending from the spring 22 between its ends. At one end of the spring 22 there is a second fulcrum lug 32 engaging the shoulder 24. To maintain the fulcrum lugs of the tension spring in contact with the shoulder 24, a circumferential adjusting wedge 34 is provided having an inclined toothed portion cooperating with an abutment lug 36 on the tension spring 22 formed between the fulcrum lugs 38, 32. The adjusting wedge is retained within the groove in the side circular wall of the thread case by reason of its engagement with more than 180 degrees of arc along the circular side wall surface, and to maintain the Wedge member accurately in place, it is grooved along its inner surface to fit a rib- 38 along the circular thread case wall. When the lug 36 is separated from the wedge 34 by temporarily bending the tension spring, the wedge may be moved circumferentially along the.

thread case wall. As the adjusting wedge 3a is moved circumferentially along the thread case wall, greater or less pressure is exerted by the tension spring 22 to force the block 29 towards the shoulder 26 along which the thread passes.

According to a feature of the present invention there are provided quick threading guideeyes arranged at opposite sides of the tension block 28 to receive the thread by lateral movement thereof rather than by inserting the end of the thread through the eyes, one guide eye being located in the circular thread case wall and one in thelug I8 which directs the thread beyond the path of the shuttle beak. In the thread case of the Gouldbourn et al. patent, the tension spring is so arranged that it passes between the guide eye in the circular thread case wall and the open end of the thread case. To permit the use of a quick threading slot entering the open end of the present :thread case, the tension spring 22, as illustrated in Fig. '7, is arranged with respect to the block 26 at a location where it will not bar access to the guide eye and an angular threading slot 48 is formed between the ends of the spring 22, terminating with the thread guide eye as at 42. To strengthen the thread case around the slot All the circular wall is thickened substantially. The slot 60 is cut into the thickened portion of the thread case wall with its apex pointed away from the thread tension block 23 and with that portion of the slot which enters the open end of the thread case forming an acute angle with the thread case end wall and also inclined from the inside of the thread case outwardly in a direction extending away from the thread tension so as to bar passage of the thread except when the thread is inclined at a corresponding angle. By so arranging the threading slot 4'3, rotation of the thread supply bobbin or cop within the thread case to such an extent as to provide slack thread will not cause the thread to become displaced from the guide eye.

To secure the thread case in place within the shuttle 12 of the present machine as well as in the machine of the patent, there is provided a swinging retainer arm 44 having a projection 36 at its lower end arranged to engage a groove 53 in the front thread case enclosing wall. The groove 38 extends radially along the front wall of the thread case and into the lug i8 through which the locking thread is guided. From the tension block 20 the locking thread passes at an angle somewhat axially of the thread case towards the front surface of the closed end wall and along the front surface of the end wall towards the work from the guide eye in the lug I8.

To provide a quick threading slot for the guide eye, indicated in the present drawing at 53), the lug i8 comprises a reversely bent finger 52 forming a slot along the bottom of the groove 68, the terminal of the finger extending in a direction opposite to the direction in which the shuttle rotates. At the end of the finger 52 there is an outwardly inclined surface 54 arranged to prevent the thread of the needle loop, indicated in Fig. 2 at 56, from becoming caught on the finger as it is carried about the thread case by the shuttle. The end wall of the thread case also has a projecting portion 58 extending over the end of the finger 52 to assist in directing the needle loop away from the end of the reversed finger. As afurther means for preventing the needle thread'from becoming caught on the finger 52, a cam surface Gil is formed along one edge of the thread case for lifting each needle loop clear of the reversed end of the finger 52.

In threading the illustrated thread case, the supply reel or pop i6 is first inserted in the usual way with a short length unwound at the end. The portion of the thread close to the unwound end is then carried laterally through the threading lot 49, along the circular wall of the thread case beneath the tension block 29 and under the finger 52 into an enlarged sight opening 62 formed near the end of the reversed finger 52, as illustrated in Fig. 4. 'The. sight opening 62 is conveniently located for inspecting the amount of' lockingithread remainingin the supply during operation of the machine, thus rendering the thread supply visible at .all times. After enterin'g'the opening" 62, the unwound end of thread is moved laterally in a reverse direction until it engages the inclined surface 54 at the end of the finger 52. The inclined surface 54 causes the thread to be carried towards the right, as shown in Figure 5, into the slot along the bottom of the groove 48, and thereafter a slight tension on the thread will cause it to assume the proper position in the guide eye 55 Having thus described the invention, what is claimed is:

1. A hollow cylindrical locking thread case for a lock-stitch shoe sewing machine comprising a circular side wall and an end wall, the remaining end of the thread case being open to receive a supply of thread, a yielding thread tension on the circular side wall, and quick threading guide eyes having open-ended thread entering slots at opposite sides of the tension to direct the thread respectively through the circular wall of the thread case to the tension and from the tension towards the work.

2. A hollow cylindrical locking thread case for a lock-stitch shoe sewing machine comprising a circular side wall and an end wall, the remaining end of the thread case being open to receive a supply of thread, a yielding thread tension on the circular side wall, a quick threading guide eye in the circular wall of the thread case having a slot entering the open end of the thread case to direct the thread from Within the thread case to the tension, and a quick threading guide l eye comprising a perforated lug extending radially beyond the circular wall at the closed end of the thread case and having a thread entering slot between the lug and the circular wall of the thread case to direct thread from the tension towards the work.

3. A hollow cylindrical locking thread case for a lock-stitch shoe sewing machine comprising a circular side wall and an end wall, the remaining end of the thread case being open to receive a. supply of thread, a yielding thread tension on the circular side wall, and a quick threading guide eye having an open-ended threading slot entering the open end of the thread case to direct the thread through a circular wall of the thread case to the tension.

4. A hollow cylindrical locking thread case for a lock-stitch shoe sewing machine comprising a circular side wall and an end wall, the remaining end of the thread case being open to receive a supply of thread, a tension member on the circular wall of the thread case, a guide eye in the circular wall of the thread case having a quick threading slot entering the open end of the thread case, and a circumferential spring surrounding more than 180 degrees of the outer surface along the circular wall of the thread case with one end engaging the tension member and the other end at the opposite side of the threading slot from the tension member.

5. A hollow cylindrical locking thread case for a lock-stitch shoe sewing machine comprising a circular side wall and an end wall, the remaining end of the thread case being open to receive a supply of thread, a guideway in the circular side wall of the thread case, a sliding thread tension member in the guideway, a circumferential bar spring surrounding more than 1.30 degrees of the outer surface along the circular wall of the thread case and having one end engaging the tension member, and a thread guide eye in the circular wall of the thread case having a quick threading slot entering the open end of the thread case and passing between the tension member and the other end of the spring.

6. A hollow cylindrical locking threadcase for a lock-stitch shoe sewing machine comprising a circular side wall and an end wall, the remaining end of the thread case being open to receive a supply of thread, a guideway in the circular side wall of the thread case, a sliding thread'tem sion member in the guideway, a circumferential bar spring surrounding more than 180 degrees of the outer surface along the circular wall of the thread case, said spring having one end engaging the tension member and a pair of spaced fulcrum lugs with an abutment lug therebetween, a circumferentially slidable adjusting member cooperating with the abutment lug to tension the spring, and a thread guide eye in the circular wall of the thread case having a quick threading slot entering the open end of the thread case and passing between the ends of the circumferential spring and adjusting member to direct the thread from the inside of the thread case to the tension member.

'7. A hollow cylindrical'locking thread case for a lock-stitch shoe sewing machine comprising a circular side wall and an end wall, the remaining end of the thread case being open to receive a supply of thread, a guideway in the circular side wall of the thread case, a sliding thread tension member in the guideway, a circumferential bar springsurrounding the outer surface along the circular wall of the thread case and having a fulcrum lug between the ends, another fulcrum lug at one end and an abutment lug between said fulcrum lugs, the opposite end of the spring engaging the tension member to actuate it towards a surface on the thread ease, a circumferentially slidable adjusting member cooperating with the abutment lug to tension the spring, and a quick threading guide eye in a circular side wall of the thread case having a slot passing between the fulcrum lug at the end of the spring and the tension member.

8. A hollow cylindrical locking thread case for a lock-stitch shoe sewing machine comprising a circular side wall having a thickened portion and a front end wall, the remaining end being open to receive a supply of thread, a thread tension on the circular wall of the thread case, a guide eye in said circular" wall having a quick threading slot of angular shape in the thickened portion of said wall entering the open end of the thread case, the apex of said slot being pointed away from the thread tension, and that portion of the slot which enters the open end of thread case being out at an acute angle through the thread case wall from the inside of the thread case away from the thread tension.

9. A lock-stitch shoe sewing machine having, in combination, a hook needle, a rotary loop taker, a hollow cylindrical thread case rotatably supported by the loop taker and formed with a circular side wall and a front end Wall, the remaining end of the thread case being open to receive a supply of thread, a groove on the outer surface of the front wall, a retaining arm on the machine having a projection engaging the groove, a quick threading guide eye in the front wall of the thread case having a thread entering slot along the groove beneath the projection of the retaining arm, and. a cam surface on the front wall of the thread case for lifting each needle loop carried by the loop taker about the thread case clear of the entrance to said slot.

10. A lock-stitch shoe sewing machine having, in combination, a hook needle, a rotary loop taker, a hollow cylindrical locking thread case rotatably supported by the loop taker and formed with a circular wall, and a front end wall having a reversed finger extending in a direction opposite to the direction of loop taker rotation to provide a quick threading guide eye and a cam surface on the end wall of the thread case for lifting each needle loop carried by the loop taker about the thread case clear of the reversed end of the finger 11. A lock-stitch shoe sewing machine having, in combination, a hook needle, a rotary loop taker, a hollow cylindrical locking thread case rotatably supported by the loop taker and formed with a circular wall, a front end wall, and a reversed finger extending in a direction opposite to the direction of loop taker rotation to provide a quick threading guide eye and having a surface at its end inclined outwardly in the direction of loop taker rotation from within the thread case to assist in directing each needle loop carried by the loop taker about the thread case away from the guide eye.

12. A lock-stitch shoe sewing machine having, in combination, a hook needle, a rotary loop taker, a hollow cylindrical locking thread case rotatably supported by the loop taker and formed with a circular wall, a front end wall, a reversed finger extending in a direction opposite to the direction of loop taker rotation to provide a quick threading guide eye and having a, Surface at its end inclined outwardly in the direction of loop taker rotation from within the thread case to assist in directing each needle loop carried by the loop taker about the thread case away from the guide eye, and a projection on the front end wall overlying the end surface of the finger for shielding the end of the finger from contact with each needle loop carried by the loop taker about the thread case.

13. A lock-stitch shoe sewing machine having, in combination, a hook needle, a rotary loop taker, a hollow cylindrical locking thread case rotatably supported by the loop taker and formed with a circular side wall and a front end wall having a reversed finger extending in a direction opposite to the direction of loop taker rotation to form a quick threading slot between the reversed end of the finger and the edge of the circular thread case wall, the end of the finger extending into an opening in the thread case end wall and a cam surface on the end wall of the thread case for lifting each needle loop carried by the loop taker clear of the opening in the front thread case wall.

14. A lock-stitch sewing machine having, in combination, a curved hook needle, a rotary shuttle, a locking thread case Within the shuttle comprising a circular side wall and a front end wall having a radial groove, the other end being open to receive a supply of locking thread, the front end wall having a quick threading guide eye at the bottom of the groove and a thread entering slot which passes along the groove, and a rotation limiting retainer cooperating with the groove to hold the thread case from movement with the shuttle.

OTTO R. HAAS.

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