US3424117A - Thread severing device for severing the looper and needle threads on double chain stitch sewing machines - Google Patents

Description

3, 69 D. SCHOPF 3,424,117 THREAD SEVERING DEVICE FOR SEVERING THE LOOPER AND NEEDLE THREADS ON DOUBLE CHAIN STITCH SEWING MACHINES Filed May 6, 1966 Sheet 0f 5 I 6 F164 V f INVENTOR DIETER SCHOPFY Wm ATTORNEY5 22% BY 6%, WW R Jan. 28, 1969 SCHOPF 7 3,424,] l 7 THREAD SEVERING DE E FOR SEVERING THE'LOOPER AND NEEDLE T ADS 0N DOUBLE CHAIN STITCH SEWING MACHINES Filed May 6, 1966 Z of 5 Sheet INVENTOR DIETER SCHOPF BY "W W AE 3,424,111 HE LOOPER AIN D DEVICE AND OFF

5 RING T BLE HIN Jan. 28, 1969 S THREAD SEVERING F NEE E EADS ON SEWING MAC I Sheet Filed May 6. 1966 IFIG.5b

INVENTOR DIETER SCHOPF 4942,, PM; W X

Jan. 28, 1969 D. SCHOPF 3,424,117

- THREAD SEVERING DEVICE FOR SEVERING THE LOOPER AND NEEDLE THREADS 0N DOUBLE CHAIN STITCH SEWING MACHINES Filed May 6, 1966 Sheet 4 of 5 IFIIG.6

INVENTOR 0| ETER SCHOPF 4W2, @012, mm @mm/ ATTORNEYS Jan. 28, 1969 D. SCHOPF' THREAD SEVERING DEVICE FOR SEVERING THE LOOPER AND NEEDLE THREADS ON DOUBLE. CHAIN STITCH SEWING MACHINES Sheet 2 of 5 Filed May 6, 1966 INVENTOR .DIETER SCHOPF United States Patent U.S. Cl. 112252 23 Claims Int. Cl. D05b 65/02 ABSTRACT OF THE DISCLOSURE A thread severing device for double chain stitch sewing machines is disclosed herein. The severing device includes a thread catcher movable between the thread carrying looper blade and the stitching plate for catching the thread and drawing the thread into clamping engagement with clamping means and into cutting engagement with cutting means whereby the looper thread is cut and clamped at a predetermined point and whereby the needle thread may be cut and released at said point. The cutting and clamping means may be movable to and retractible from the predetermined point and control provisions are disclosed for controlling the operation of the severing device and for drawing off a predetermined amount of looper and needle thread upon actuation of the severing device such that a new sewing operation may be begun.

The invention concerns a thread severing device embodied in double chain stitch sewing machines, wherein the needle thread loop lies around the blade of the thread carrying looper when the needle is in high position.

In such double chain stitch sewing machines heretofore various thread cutting devices have become known by use of which the thread chain can be separated at the end of one sewing element. However, such devices as will permit the separation of the threads whenever the seam ends inside the material have not been known.

Heretofore, in known practices, when the seam ends in the sewing material, it has been customary for the seamstress to turn the hand wheel opposite to the normal running direction in order to throw off the loop of the needle thread from the looper blade, whereupon the seamstress would pull away the sewing material from below the pressure foot which had been lifted and would separate the threads with a pair of scissors or a cutting knife.

In order to simplify the turning of the hand wheel in the opposite direction, disclosure has also been made of a motor which carries out this turning backward after the stopping of the sewing machine.

In either case, however, the severing of the threads in the case of double chain stitch sewing machines is awkward and time consuming, whenever the seam ends within the material, and a relatively large loss of thread will occur. It is true, that it has been known in the case of buttonhole machines, which use a double chain stitch, to separate the threads below the stitching plate. However, in the case of these sewing machines, the development of the stitch takes place in a different manner than it does in the case of normal double chain stitch sewing machines, where the loop of the needle thread in the case of the high position of the needle lies around the blade of the thread carrying looper. Besides, in the case of these buttonhole sewing machines, the separation of the thread has been controlled automatically with the sewing process, whereas in the case of a normal sewing machine the course of the work process is controlled at will. For these 3,424,117 Patented Jan. 28, 1969 reasons, it is not possible to transfer the thread severing equipment of buttonhole sewing machines to normal double chain stitch sewing machines.

The present invention serves the purpose of cutting off the threads on double chain stitch sewing machines wherein the loop of the needle thread in the high position of the needle lies around the blade of the thread carrying looper, whenever the seam ends in the material being sewn, and is based on the problem of creating a thread severing device by which the threads can be cut off closely below the material and be held in a manner, which assures that a faultless formation of the stitch will be guaranteed upon restarting of the sewing machine.

This problem essentially is solved by providing a thread seizing device or thread catcher which moves between the looper blade and the stitching plate, and will cooperate with a cutting blade and a fiat Elamping spring or spring clip, and whose seizing beak or catcher hook moves on a course in relation to the looper being in its foremost end position, said course extending within the area of the looper point, across the looper blade and from there through the path of the needle up to a point on that side of the path of the needle which faces away from the looper. At the same time, the thread catcher moves preferably between the cutting blade and the clamping spring or clip and has a cutting edge which corresponds to the edge of the cutting blade. The clamping spring or clip presses the catcher hook against the cutting blade and serves, at the same time, for clamping the threads against the thread catcher, whereby at least the severed looper thread extending to the eye of the looper is retained by the clip spring in the end position of the catcher hook. Through this design and arrangement of the cooperating elements it becomes possible to arrange a thread severing device or thread catcher in the limited space between the looper blade and the stitching plate which catches the looper and the needle threads, cuts them off and retains them in such a position that a faultless stitch formation is insured when the sewing machine starts up again.

In order to avoid an automatic unraveling of the double chain stitch seam from the direction of the end of the seam, for practical purposes the cutting blade and the spring clip are movable in relation to the thread catcher, in such a manner that the shearing effect of the cutting edges takes place a predetermined distance from the path of the needle and the end position of the cutting edges with the cutting edges spaced from the upper edge of the stitch hole at a distance approximately twice the length of the stitch.

Another embodiment of the thread severing device or thread catcher consists in providing one catcher hook or seizing beak each for the needle thread and the looper thread, preferably on one common thread catcher. Through this arrangement it becomes possible to draw out the threads individually, to cut them off and to clamp them.

In the case of the arrangement'of both seizing beaks or catcher hooks on one thread catcher, the catcher hook for the needle thread has been displaced in the direction of movement of the hooks, in such a manner in relation to the catcher hook for the looper thread that in its pushed out or projected position it will extend between the looper thread and the needle thread. The novel arrangement is such that only the catcher hook or seizing beak for the looper thread cooperates with the clamping spring or clip, in order to clamp the looper thread in the rest position of the catcher hook.

Thus, a clamping of the needle thread will be avoided without impairing the safe clamping of the looper thread. This is particularly important when sewing thin materials,

since a clamped needle thread at the beginning of a seam leads to puckering.

A preferred embodiment of the cutting-off device is characterized by the fact that the spring clip is equipped with a notch, the edge of which is spaced from the free end of the spring clip at a distance that is smaller than the clamping surfaces of the catcher hooks.

Other embodiments consist in this, that the catcher hooks are displaced laterally in relation to one another in their direction of movement and in that the spring clip covers only the course of movement of the catcher hook for the looper thread, or else in that that surface of the catcher hook which faces-the spring clip and which is intended for the needle thread recedes in relation to the remaining surface of the catcher hook, or in that the catcher hook for the needle thread has an edge to break the needle thread.

Finally, it is also possible to displace the spring clip with and relatively to the thread catcher and merely to provide on the spring clip a blind catcher hook for the needle thread.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a front elevation, parts being broken away, showing a double chain stitch sewing machine embodying the invention.

FIGURE 2 shows a part of the opened machine bed viewed from above.

FIGURE 3 is a perspective view schematically illustrating one form of thread cutting device embodying the invention, the same being shown in the swung-in or projected condition.

FIGURE 4 shows the thread cutting device in the retracted position.

FIGURE 5 is an enlarged sectional view showing the end of the seam with threads cut off and protruding a considerable distance from the fabric.

FIGURE 5 is a view similar to FIGURE 5 with the dangling needle thread pulled in toward the preceding needle thread loop.

FIGURE 6 is a circuit diagram.

FIGURES 7 and 8 are views similar to FIGURES 3 and 4 and showing similar positions of a modified form of the invention.

In the embodiment of the invention herein disclosed the sewing machine has a customary housing 1, in which a needle bar 2 carrying a needle 3 is guided. The needle bar and needle are driven in the known manner and the needle operates together with a thread carrying double chain stitch looper 4. The drive of the machine takes place via a belt pulley 5, which is connected with a known type of transmitter, not shown, which puts the needle into high position in the stopping position. The needle thread 6 and the looper thread 7 are moved via tension discs 8, 9 and the customary thread guiding parts to the needle 3 and the looper 4. A spreader 10 cooperates in the well known manner with the needle 3 and looper 4 in the formation of stitches, the spreader serving to widen out the thread triangles during sewing, opposite to the normal sewing direction.

Additionally, according to the present invention, thread draw-off parts 11, 12 have been provided which, preferably, have been adjustably secured to a shiftable plate 13. These thread drawing-off parts, furthermore, carry disc spacers 14, 15, which are engageable between the tension discs 8 and 9 for deactivating the same. An actuating electromagnet 16 is provided for bringing about desired shifting of the plate 13 which magnet operates a bar 17 via a lever 18 engaging in a slot 19 of the plate 13, as shown in FIGURE 1.

The actuating magnet 16 also serves in the operation of the device for severing the threads via moving means including a draw bar 21. The draw bar 21 is connected with a lever 22 which can be swung about an axis 23 and which carries a thread catcher 24. The thread catcher 24 operates together with a cutting blade 26 and aclamiping spring or clip 27 and is guided between these parts. Preferably, the cutting blade 26 and the spring clip 27 are movable relative to the thread severing device or thread catcher 24 and, for this purpose, they have been secured to a carrier 25 that can be swung about the swinging axis 23. The carrier 25 is connected with an anchored tension spring 28 and has a stop 29 which is engageable with a stop portion of the support means 31 for the cutting device.

In the illustration in FIGURE 4, the thread cutting device is in the starting position. The thread seizing beak or thread catcher 24 lies against the carrier 25 of the cutting blade 26 and against the clamping spring or clip 27, and has swung back the carrier 25 from the position shown in FIGURE 2 and against the pull of the spring 28. If the magnet is now switched on, the thread severing device will swing to position shown in FIGURE 3. The thread catcher 24 will be disposed with its seizing beak or catcher hook 32 above the looper blade approximately within the area of the looper point when the magnet 16 has been energized. The carrier 25 will have followed the thread catcher 24 under the influence of the spring 28, until the stop 29 abuts against the support 31. At this time the cutting edge 33 of the cutting blade 26 will be spaced from the upper edge of the stitch hole the stitch plate at a distance of about a double stitch length. Spring 28 and stop 29 cooperate to maintain the cutting blade 26 and clamping spring 27 a predetermined distance from the needle path.

Simultaneously, the thread draw-off parts 11, 12 will have seized the needle thread 6 and the looper thread 7 and drawn them off by a predetermined length. Preferably, the tension disk spacers 14, 15 will have moved in simultaneously between the tension discs and have released the thread tension, in order to facilitate the drawing off of the threads.

If the magnet is now switched off, then the thread catcher 24 swings back through the path of the needle up to a point which lies on that side of the path of the needle which faces away from the looper (FIGURE 4). At the same time, the seizing beak or catcher hook 32 of the thread catcher will seize the strand 35 of the looper thread 7 guided from the looper eye 34 to the last stitch, as well as that strand 36 of the needle thread 6 extending from the looper blade to the last stitch. When the catcher hook reaches the clamping spring or clip 27 it claimps both strands thereagainst and then cuts them off immediately afterwards against the cutting edge 33 of the cutting blade. After the catcher hook 32 has been retracted into position between the cutting blade 26 and the clamping spring or clip 27, the thread catcher 24 again engages against the carrier 25, and on its path into its end position, it will move said carrier with it against the retractile force of the spring 28.

The thread draw-oft parts 11, 12 likewise move back into position for releasing the necessary quantity of thread which is required to draw out the threads during swinging back of the thread severing device into its end position. Simultaneously, the disc spacers 14, 15 retract from between the tension discs 8, 9, whereupon said discs will again act on the threads 6, 7 and clamp the same. Preferably, enough needle thread is drawn oif so that the latter will be released by the clamping spring or clip 27 just prior to the thread severing device reaching its end position. Also, enough looper thread will be drawn off so that it will remain held by the clamping spring or clip 27 in its end position. Thus, the looper thread will be held tensed in its position on that side of the path of the needle which faces away from the looper. As a result, the needle will enter between the looper blade and the clamped in strand of the looper thread when the machine starts Operating again, so that the looper thread upon the return of the looper places itself around the needle. Thus a faultless stitch formation will be insured. At least until after the formation of the first stitch, the looper thread will remain clamped in and will finally be drawn off from the spring clip 27 by the advance of the material through the machine.

The threads are cut olf approximately at a length as shown in FIGURE 5 so that the needle thread 6 and the looper thread 7 protrude by about a double stitch length from the bottom side of the material. Thus, an automatic unraveling of the seam has been prevented, since the needle thread will prevent a sliding back of the loop of the looper thread through the preceding loop of the needle thread. Preferably, however, the drawing olf of looper thread 7 will be adjusted in such a manner, that the looper thread 7 will draw the suspended end of the needle thread 6 toward the preceding needle thread loop and will clamp it there, as a result of which an increased security is oifered against unraveling of the seam. See FIGURE 5 Instead of the way shown here, naturally it is also possible that a plurality of needles may cooperate with the thread guiding looper even though several needle thread loops may hang on the looper blade, still they will be grasped by the catcher hook 32 and cut off in the same manner. Besides that, the parts of the cutting-off device may also move in a straight path which runs approximately tangentially to the are described by the thread catcher in the embodiment shown.

The control circuit, seen in FIGURE 6, is provided in order to prevent the magnet 16 from being switched on for the operation of the thread severing device during the sewing, a relay 41 has been provided, which obtains current only when the sewing machine operates and which opens a switch 42 in the circuit leading to the magnet 16. In this manner the circuit to the magnet will be interrupted when the machine is running and it will not be possible to switch in the magnet 16. If the machine stops, the relay 41 will be deactivated and the switch 42 closes the contacts in the circuit of the magnet 16. For energizing the magnet there is provided an additional switch 43 which can be manually operated at will, which preferably is arranged on the treadle controlling the transmitter. The switch 43 will be closed, for example, whenever the treadle is moved opposite to the transmitter engaging position. If a transmitter is used which is adapted for stopping the needle, by choice either in high or low position, then an additional switch 44 will be provided in the circuit to the magnet 16, which, controlled by the transmitter, will open when the needle is at its lower point and will close when the needle is in high position.

In order to deenergize the magnet after switching on, and in order to avoid a repeated switching on, an automatic holding relay 45 has been provided. In the control circuit leading to the automatic holding relay 45, there is a switch 46 which closes the control circuit when the relay 41 is energized. As a result of this, the relay 45 is activated and closes a holding circuit via the holding contacts 47, in which a switch 48 has been arranged. Simultaneously, the automatic holding relay 45 will bridge contacts in the circuit of the magnet 16 with a switch 49.

If the sewing machine stops and the relay 41 is now deactivated, the switch 42 is closed and the switch 46 is opened. The automatic holding relay 45 remains energized via its holding circuit, so that the switch 49 also remains closed. Assuming that the needle is in its high position and the switch 44 is likewise closed, then the only break in the circuit to the magnet 16 will be the switch 43. If this switch 43 is now closed, the magnet will be energized and will initiate the cutting process.

The magnet when energized will open the switch 48 and thus interrupt the holding circuit to the automatic holding relay 45, which is deactivated. As a result of this,

the switch 49 is opened and the circuit of the magnet 16 is interrupted, as a result of which the magnet 16 is deenergized. It will be apparent that with this the switch 48 in the holding circuit of the relay 45 is again closed, since however the switch 47 remains open and the switch 46 does not close, before the sewing machine starts to operate again, the switch 49 also remains open. A renewed closing of the switch 43, therefore, remains without effect. The magnet 16 can be switched on again only through the switch 43, after the machine has again sewn and after the automatic holding relay 45 has been energized via the relay 41. This insurance against repeated cutting is necessary in order to assure that the clamping spring or clip 27 will not release the looper thread before at least one stitch has been sewn.

In the embodiment shown in FIGURES 7 and 8 parts corresponding to parts shown in FIGURES 3 and 4 have like reference characters applied thereon with the addition of an exponent whereas modified parts have distinct reference characters applied thereon.

In this modified showing the thread catcher 24 carries two thread seizing beaks or catcher hooks 52 and 53, both of which coact with the cutting blade 26*. The spring clip 27 has a notch 54 formed therein (FIGURE 8). If the thread catcher 24 is swung in (FIGURE 7), then the catcher hook 52 will move beyond the strand of the looper thread 7 in the direction of the looper point 4*, while the hook 53 is in a swung in position between the loop of the needle thread 6 hanging on the looper and the strand of the looper thread 7 leading to the last stitch. If the thread catcher 24 swings back into its starting position, then the hook 52 will grasp the looper thread, while the hook 53 will seize the strand of the needle thread loop running from the looper blade to the last stitch. Both threads will thus be cut off against the cutting blade 26 but only the looper thread 7 will be clamped in between the catcher hook 52 and the clamping spring or clip 27 The catcher hook 53, in the end or starting position, is in the area of the notch 54 of the spring clip 27 as a result of which the needle thread is released, or in other words, will not be clamped.

The same effect can be achieved if the catcher hooks are displaced laterally in relation to one another in their direction of movement and if the spring clip merely covers the path of movement of the catcher hook 52. As a result of this, the catcher hook 53 would not engage with the clamping spring or clip 27, and thus the needle thread likewise would not be clamped.

Besides, the clamping of the needle thread can be avoided in that the catcher hook 53 is formed with a recess at the bottom side as compared to the catcher hook 52 and thus, in the end or starting position is disposed at a distance from the spring clip 27, or in that the catcher hook 53 is formed with a cutting blade on which the needle thread will be broken, before the catcher hook 53 reaches the spring clip 27.

Finally, it is also possible that the catcher hook 53 may be arranged on the spring clip 27. In this case the clamping spring or clip 27 together with the thread catcher 24 swings into position in which the catcher hook 53 will be between the needle thread loop and the looper thread. On swinging back, the thread catcher 24 of the spring clip 27 will be in advance and clamp the looper thread 7 between the catcher hook 52 and the catcher hook 53, which is located on the spring clip, whereupon both elements will swing back together and both threads 6*, 7 will be cut ofi against the cutting blade 26*". In this case, too, the needle thread 6 is not clamped in.

While preferred embodiments of the invention are disclosed herein, it is to be understood that other specific arrangements of the parts may be provided within the scope of the invention as defined in the appended claims.

I claim:

1. A thread severing device for cutting threads on a double chain stitch sewing machine of the type including a needle plate, a reciprocating needle and a thread carrying looper spaced from said needle plate in the direction of needle reciprocation, said thread severing device comprising cutter means movable to a first point where thread cutting is to be eifected, and thread catching means movable with said cutter means to said first point, said catching means movable to a second point for catching the thread and moving the thread from said second point to said first point for thread cutting cooperation with said cutter means at said first point.

2. A thread severing device according to claim 1 further including movable clamping means and means for moving said cutter means and clamping means to said first point at a predetermined distance from the path of said needle and maintaining said cutter and clamping means at said first point during the timev said thread catching means moves to and from said second point, said means for moving said cutter and clamping means moving said thread catching means into thread cutting cooperation with said cutter means at said first point.

3. A thread severing device according to claim 1 comprising actuating means for actuating said thread catching means, and control means including interruption means for precluding operation of said actuating means while the sewing machine is running and for preventing repeated operation of actuating means once the sewing machine has stopped running.

4. A thread severing device for cutting threads on a double chain stitch sewing machine of the type including a needle plate, a reciprocating needle and a thread carrying looper spaced from said needle plate in the direction of needle reciprocation, said thread severing device comprising cutter means for cutting a thread, clamping means, thread catching means movably mounted between said clamping means and said cutter means and moving means for first moving said thread catching means into thread engaging position and then moving said thread catching means into cooperation with said cutter means and said clamping means to effect thread cutting at one side of said catching means and to effect thread clamping against a further side of said catching means.

5. A thread severing device according to claim 4 wherein said thread catching means comprises a cutting edge and said cutter means comprises a cutter blade, said cutting edge being positioned to move in thread cutting relation with said cutter blade when said catching means is moved into thread cutting cooperation with said cutter means.

6. A thread severing device according to claim 4 wherein said thread catching means comprises a catcher hook and said clamping means comprises a spring clip positioned to press against the underface of said catcher hook when said catching means is moved into thread cutting cooperation with said cutter means.

7. A thread severing device according to claim 4 wherein said clamping means is adapted to clamp a looper carried thread against said catching means on the opposite side of the needle path from said thread carrying looper.

8. A thread severing device for cutting threads on a double chain stitch sewing machine of the type including a needle plate, a reciprocating needle and a thread carrying looper spaced from said needle plate in the direction of needle reciprocation, said thread severing device comprising cutter means for cutting a thread, thread clamping means, thread catching means movably mounted between said clamping means and said cutter means, carrier means for carrying the cutter means and clamping means, said carrier means and thread catcher means mounted for swinging movement about a common axis, and moving means for first moving said thread catching means into thread engaging position and then moving said thread catching means into thread cutting cooperation with said cutter means.

9. A thread severing device according to claim 8 further including biasing means and stop means, said biasing means biasing said carrier means toward said stop means.

10. A thread severing device according to claim 9 wherein said catching means contacts said carrier means to maintain said thread catching means, cutter means and clamping means in an end position when said moving means is unactuated.

11. A thread severing device for cutting threads on a double chain stitch sewing machine of the type including a needle plate, a reciprocating needle and a thread carrying looper spaced from said needle plate in the direction of needle reciprocation, said thread severing device comprising cutter means for cutting a thread, clamping means, thread catching means movably mounted between said clamping means and said cutter means and comprising first catcher hook means for catching the needle thread and second catcher hook means -for catching the looper thread, and moving means for first moving said thread catching means into thread engaging position and then moving said thread catching means into thread cutting cooperation with said cutter means.

12. A thread severing device according to claim 11 wherein said first catcher hook is spaced from said second catcher hook in the direction of movement of the catching means, whereby said first catcher hook is adapted to extend between the looper thread and the needle thread when said thread catching means is in its thread engaging position.

13. A thread severing device according to claim 11 wherein said second catcher hook is positioned to cooperate with said clamping means for maintaining a looper thread in clamped condition and said first catcher hook is positioned to release a needle thread when said thread catcher means has moved from said thread engaging position.

14. A thread severing device according to claim 11 wherein said clamping means comprises a spring clip having a notch formed therein, said notch being adjacent said first hook when said catcher means has been moved from thread engaging position whereby said notch plrecludes clamping of said needle thread by said spring c 1p.

15. A thread severing device according to claim 11 wherein said first and second hooks are disposed laterally with respect to the direction of movement of said catching means and said clamping means is positioned to cooperate with said second hook only to clamp only the looper carried thread.

16. A thread severing device according to claim 11 wherein the surface of said first hook facing the clamp ing means recedes relative to the corresponding surface on said second hook, said clamping means clamping 51ml the looper thread to the surface of said second 17. A thread severing device according to claim 11 18. A thread severing device for cutting threads on a double chain stitch sewing machine of the type including a needle plate, a reciprocating needle and a thread carrying looper spaced from said needle plate in the direction of needle reciprocation, said thread severing device comprising cutter means for cutting a thread, thread catching means, moving means for first moving said thread catching means into thread engaging position and then moving said thread catching means into thread cutting cooperation with said cutter means, thread draw-otf means, and actuating means including electromagnetic means for simultaneously actuating said thread catching means and said thread draw-off means.

19. A thread severing device according to claim 18 further comprising thread tensioning means, said thread draw-off means comprising means for deactivating said thread tensioning means.

20. A thread severing device for cutting threads on a double chain stitch sewing machine of the type including a needle plate, a reciprocating needle and a thread carrying looper spaced from said needle plate in the direction of needle reciprocation, said thread severing device comprising cutter means for cutting a thread, thread catching means, and moving means for first moving said thread catching means into thread engaging position and then moving said thread catching means into thread cutting cooperation with said cutter means, actuating means including electro-magnetic means for actuating said thread catching means and control means including interruption means for precluding operation of said actuating means while the sewing machine is running and for preventing repeated operation of said actuating means once the sewing machine has stopped running, said interruption means including a first switch in series connection with a second manually operable switch, and an automatic holding relay connected to said first switch for closing of said first switch upon energization of said relay.

21. A thread severing device according to claim 20 for said holding relay including a third switch connected to said electromagnetic means for opening upon energization of said electromagnetic means.

22. A thread severing device according to claim 21 wherein said control means comprises a control circuit for said holding relay including a fourth switch connected to a second relay, said fourth switch being adapted to be closed upon energization of said second relay during operation of the sewing machine.

23. A thread severing device according to claim 22 wherein said control means comprises a fifth switch connected to said second relay, said fifth switch being adapted to be opened upon energization of said second relay during operation of the sewing machine.

References Cited UNITED STATES PATENTS 1,395,274 11/ 1921 Hagelstein 112252 2,335,827 11/1943 Gunther 112252 3,211,117 10/1965 Speichermann et al. 112252 1,234,258 7/1917 Barron 112252 1,883,654 10/1932 Ericsson 112-252 wherein said control means comprises a holding circuit 25 HERBERT F. ROSS, Primary Examiner.

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