US1338374A - Thread-trimmer for sewing-machines - Google Patents

Description

l. KIEWICZ.

THREAD TRIMMER FOR SEWING MACHINES. APPLlcATloN mep ^Pn.1o, |913. nzngwen Dsc. 15, 1919.

3 SHEETS-SHEET 1.

Patented Apr. 27, 1920.

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AHys.

1. mfwlcz. THREAD TRIMMEFI FOR SEWING MACHINES.

APPLICATION FILED APR.' I0, |918. RENEWD DEC. I5, I9l9.

Patented Apr. 27, 1920.

3 SHEETS-SHEET 2.

FigA.

InvenIor. John Kiewicg I-w 76W@ Mam a Aw l. KIEWICZ.

THREAD TRIMMER FOR SEWING MACHINES.

APPLICATION FILED APR. 10. 1918. RENEwED Dic. 15,1919.

v 1,3 Patented Apr. 27, 1920.

3 SHEETS-SHEET 3.

UNITED STATES PATENT OFFICE.

JOI-IN KIEWICZ, OF BOSTON, MASSACHUSETTS, ASS'IGNOR TO THE REECE BUTTON HOLE MACHINE COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

THREAD-TRIMMER FOR SEW'INGr-MACHINES.

Application filed April 10, 1918, Serial No. 227,622.

To all whom t may concern:

Be it known that I, JOHN Kmwioz, a citi- Zen of the United States, residing at Boston, county of Suffolk, State of Massachusetts, have invented an Improvement in Thread- Trimmers for Sewing-Machines, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the drawing representing like parts. f

This invention relates to sewing machines and particularly to buttonholesewing machines, and the object of the invention is to provide a novel device for severing the n needle 8.

under thread and stay-cord close to the work at the end of the stitching operation on each buttonhole. The device herein shown is in some respects similar to that illustrated in my co-pending application Se. No. 203,889, filed November 26, 1917, and is in the nature of an improvement on said device.

The device illustrated in said application comprises two jaw members carried by the clamp plate which is removable from the frame, means to move the jaw members into position to grip the under-thread and staycord beneath the work at the end of the stitching operation and then to retract said closed jaw members so as to draw out a length of both the stay-cord and the underthread, and a knife which is operative after the jaw members have thus been retracted to cut the under-thread and stay-cord close to the work. n

In my present invention I retain the two jaw members,but construct them so thatthey operate vnot only to draw out the underthread and stay-cord, but also'to cut the latter, and I have also simplified the ymechanism :for operating the jaws. y p v In order to give an understanding ofmy invention, I have illustrated in the drawings a selected embodiment thereof which will now be described, after which the novel features will be pointed out in the appended* claims. v

In the drawings, Figure 1 is a side view of a portion of the sewing machine having my improvements applied thereto;

Figs. 2, 3, 4f and 5 are plan views of the clamp plate with the thread-cutting` mechanism thereon, said views showing the mechanism in different relative positions;

Fig. 6 is an underside view of the front Specification of Letters Patent.

Patented Apr. 27, 1920.

Renewed December 15, 1919. Serial No. 345,124.

end of the bed-plate showing the ends of the actuating levers;

F ig. 7 is an enlarged section on the line nur, rig. e;

the manner ,in which the block 11 of the work-holding means vretains the jaw members in their retracted position.

1 indicates the ybed-plate of the sewing machine from which rises the head or overhanging arm- 2 in which reciprocates the usual needle-bar l which carries the upper Situated beneath the bed-plate 1 .is an under-thread-handling mechanism of any usual type `which is indicated generally by 5 and which is provided with the throatplate 12 having the aperture 18 through which the under-thread 6 and stay-cord 7 are delivered.

The work in which the buttonhole is being formed is indicated at lw and is held during the sewing operation by work-holding means of any usual type which is given its feeding movement during the stitching on a buttonhole by the usual feed cam 42. The work-holding means is herein illustrated as comprising a clamp-plate 8 on which the work rests and work-clamps 9 that clamp the work to the plate, said work clamps being ,carried by arms 10 supported by a block 11 that is pivotally connected to the clamp-plate 8 so as to allow the work clamps to close onto the work or to be opened to release the work, all as usual in buttonhole-sewing machines.

Since the present invention relates solely to the device for cutting and trimming the under-thread and stay-cord close to therwork at the end of the stitching operation. on each buttonhole, I have not thought it necessary either to illustrate or describe further the buttonhole sewing machine.

My improved under-thread and stay-cordtrimming mechanism comprises two jaw members 14 and 15 which are situated directly above the clamp-plate 8 and between the latter and the work w and which are Y pivotally connected together by the pivotal stud 16, said stud extending through and beneath the jaw members and the lower end thereof operating Vin a guiding slot 17 Y formed in the clamp-plate 8. The jaw members thus are capable of having a bodily movement toward and from the throat-plate 12 and also an opening and 'closing movement about the pivot 16.

The jaws 14 and 15 are each provided with a thread-receiving notch 26 and with a beak 27, the beaks being so arranged that when the jaws are closed they will overlap each other.

During the sewing operation on the buttonhole the jaws 14 and 15'y are in their retracted open position shown in Fig. 2, in which position they are situated between the throat-plate 12 of the under-thread mechanism andJ the front of the machine. At the' end of the stitching on a buttonhole the two jaws 14 and 15 ai'e moved bodily toward the throat-plate while in their open relation so as to carry them into the position shown in Fig. 3. During this movement the beaks 27 pass either side of' the under-thread 6 and sta-y cord 7 that extend from the work through the throat-plate, so that said under thread and .stay-cord are situated opposite the notches 26. The jaws are then closed suiliciently to cause the beaks 27 to overlap slightly so that the notches 26 form a closed aperture in which the under-thread and stay-cord are received. After the jaws have been thus closed they are moved backwardly bodily into the position shown in Fig. 4 thereby drawing out from the source of supply a length of under-thread and stay-cord, after 'which the under-thread and stay-cord are cut close to the work. This is accomplished by providing the notches 26 with cutting edges 28 and by providing means forgiving the jaws a further closing movement, as shown in Fig. 5, so that the cutting edges 28 will act on the stay-cord and underthread with a shearing cut thereby to sever them.

I will now describe the mechanism T prefer to employ for giving the aws 14 and 15 the above-described sequence of movements.

The means T employ 'for holding the jaws in their retracted position during the stitch.- ing of the buttonhole is controlled by the work clamp, so that when the work-.cl amps 9 are raised to unclamp the work the uws' will be moved 'forwardly fromthe position shown in Fig. 2 to that shown in Fig. The upper end of the stud 16 is received in a slot 30 formed in the end of a.l lever 31 which is pivoted to the clamp plate 3 at 32. Said lever has a strut 33 connected thereto, the end of which engages the block 11 oi3 the work clamp when said work clamp is in operative clamping position. The lever 31. has an. arm 34 extending therefrom to which is connected a pulling spring V35 that tends to swing the lever 31 to the right. So long as the worlrclamp 9 is lowered, the strut 33 will engage. the block 11 and hold the jaws- 14 and 15 in their retracted position againstv the action of the spring 35. Vhen the workelamps 9 are raised to unclamp the work, then the lower edge of the block 11 is carried above the end of the strut member 33 thereby releasing the latter and allowing the spring 35 to move` the jaws forwardly into the position shown in Fig. 3.

The closing movemento'f the jaws is controlled by a lever 21 pivoted to the frame at 22. This lever is provided with a pin 20 which operates in a slot 19 formed in the rear end 18 of the jaw 15 and also operates in an opening 24 formed in the rear end 23 of the jaw 14. The opening 24 is provided with the inclined edge 25. The lever 21 is acted upon by a spring 36 which tends to swing it inwardly toward the right and thereby maintain the pin 20 at the inner end of the slot 19 and opening 24. When the pin 2() is in this position the jaws are inopen relation, as shown in Figs. 2 and 3. After the jaws have been moved forwardly into the position shown in Fig. 3 the lever 21 is swung backwardly, during which movement the pin 2() acts against the inclined wall 25 ot the opening 24 and against the wall of the slot 19 thereby swinging the jaws into the partially-closed position shown in Fig. 4. This is done while the aws remain in their forward position shown in Fig. 3 so that the beaks 27 will pass behind the underthread and stay-cord, thus locking them in the opening formed by the notches The length of the slot 19 is such that when the swinging movement of the lever 21 has brought the pin 20 to the rear end of the slot, the jaws will be in their partiallyclosed position shown in Fig. 4. The lever 21 has a range of movement greater than necessary to bring the pin 20 to the rear end of the slot 19, so that during the further swinging movement of said lever, the in 20 will act against the end oil the slot 19 and will thereby move the jaws bodily to the left into the position shown in Fig. 4, this movement being accomplished while the jaws are retained in their partially-closed position. This bodily backward movement of the jaws results in pulling out a length of under-thread and. 'stay-cord, as shown in Fig. 4, and during such movement the stud 16 travels backwardly in the slot 17.

The meansjfor giving the lever 21 its backward swinging movement is similar to the corresponding means shown in my abovementionefl fio-pending application, and -it comprises an elbow-lever 37 pivoted to the iinderside'oi1 the bed plate at 52 and which is acted upon by a spring 53 that normally holds itin the position shown in Fig. 5. One arm 54 of thiselbow-lever is engaged andV actuated hya lever 39 pivoted toturn about a stud 40.V and the other arm 55 lof said elbow-lever adapted to contact with a .pin or projection 38 depending from the lever 21. The swinging movement of the lever 39 will, therefore, operate through the elbowlever 37 to give the lever 21 the necessary rearward swinging movement. The lever 39 is actuated by a cam 41 which is rigid with the usual main cam 42 of the buttonhole sewing machine by which the work-holding means is given its feeding movement. This cam 41 is similar to the corresponding cam illustrated in my co-pending application and is constructed so that at the proper time in the cycle of operations it will actuate the lever 39 thereby to cause the rearward movement ofthe lever 21.

For cutting the stay-cord after the jaws have been pulled backwardly into the position shown in Fig. 4, I employ a lever 43`also pivoted at 40 and acted upon by the cam 41, the end 44 of said lever being adapted to engage a depending finger 45 extending from the end 23 of the jaw 14. The shape of the cam 41 is such that after the lever 39 has been actuated thereby to cause the jaws 14 and 15 to be retracted into the position shown in Fig. 4, the lever 43 will be actuated to bring the end 44 thereof against the finger 45 thereby giving a swinging movement to the jaw 14 into the position shown in Fig. 5 which will cause the shearing edges 28 to cooperate to cut the underthread and stay-cord. The aperture 24 is made large enough so as to permit this cutting movement of the jaw 14.

The jaw 14 is shown as having a wedgeshaped projection 46 which is adapted to enter under a hold-down member 47 carried by the jaw 15, the purpose of this being to insure that the cutting edges 28 will be held in shearing relation during the cutting operation.

The jaws 14 and 15 are normally held open by means of a spring 4S and an additional spring 49 is provided which only becomes compressed after the jaws are closed. The spring 49 is relatively stifl'I and the purpose of it is to give the jaws an initial opening movement after the lever 43 has been operated to effect the severing of the underthread and stay-cord.

In actual practice the jaws will be covered by a cover-plate 50, said plate being so shaped that it will cover the jaws when they are in their retracted position, but when the jaws are moved into the position shown in Fig. 3 they' will project slightly beyond the edge 51 of the plate. The location of the edge 51 is indicated by the dotted line 51 in Figs. 2, 3 and 4. The work w rests on the plate 50 and said plate, therefore, protects the work from the thread-trimming mechanism.

While I have herein illustrated a selected embodiment of the invention, I do not wish to be limited to the constructional features shown.

I claim:

1. In a sewing machine, the combination with work-holding means, of stitch-forming mechanism including under-thread-handling mechanism, a pair of pivotally-connected jaw members, each having a threadreceiving notch and a beak, means operative at the end of a stitching operation to move the jaw members into position to engage the thread, means to partially close said jaws thereby to bring the beaks into overlapping relation and to inclose the thread in the notches and then to move the jaws bodily to draw out a length of thread, and means to give the jaws a iinal closing movement thereby to sever the thread.

2. In a sewing machine, the combination Y with work-holding means, of stitch-forming mechanism including under-thread-handling mechanism, a pair of pivotally-connected jaw members situated beneath the work and each provided with a thread-receiving notch and a beak, means operative at the end of a stitching operation to move said jaws into position to engage the underthread beneath the work, means to partially close said aws thereby to bring the beaks into overlapping relation and to inclose the under-thread in the notches of the jaws and then to move the jaws bodily to draw out a length of under-thread, and means to give said jaws a iinal closing movement thereby to sever the thread.

3. In a sewing machine, the combination with work-holding means, of stitchforming mechanism including under-threadhandling mechanism, a pair of pivotallyconnected jaw members carried by the workholding means beneath the work, each jaw member having a thread-receiving notch provided with a cutting edge and a beak, means operative at the end of a stitching operation to move the jaws into position to engage the under-thread, means to partially close said jaws thereby to bring the beaks into overlapping relation and then to move the jaws bodily and draw out a length of under thread, and means to give said jaws a final closing movement thereby to sever said thread.

4. In a sewing machine, the combination with a frame, of work-holding means removable therefrom and comprising a clamp plate, stitch-forming mechanism including an under-thread-handling mechanism provided with a throat-plate, a pair of pivotally-connected jaw members carried by the clamp plate, and each provided with a notch having a cutting edge and a beak beyond the notch, means operative at the end of a stitching operation to move said jaws on the clamp plate into thread-engaging position, means to partially close said jaws thereby to bring the beaks into overlapping relation and then to move the jaws bodily on the clamp plate to draw out a length or thread from the throat-plate, and means to give said jaws a final closing movement thereby to sever the thread.

5. In a sewing machine, the combination with work-holding means, of Stich-forming mechanism including under-thread-handling mechanism, a pair oi' pivotally-connected jaw members carried by the workholding means and each provided with a. notch having a cutting edge and a beak beyond the notch, means operative at the end of the stitching operation to carry the jaw members into thread-engaging position, a lever acting on the jaw members and operating first to partially close said jaws thereby to inclose the thread in the thread-receiving notches and then to move the jaws bodily to draw out a length of under-thread, and means acting on one jaw to complete the closing movement of the jaws thereby to sever said thread.

6. In a sewing machine, the combination with worlvholding means, oi stitch-forming mechanism, a pair of pivotally-con-nected jaw members, each having a thread-receiv ing notch provided with a cutting edge and a beak beyond the notch, one jaw member having at its rear end an inclined slot, and the other an opening provided with an oppositely-inclined edge, a pivoted lever` having a pin extending through said slot and opening, means to swing the lever to carry the pin to the rear end of the slot and cause it to act against the inclined side of said opening whereby the jaws are closed sufi'ciently to cause the beaks to overlap so that the thread is inclosed in thenotches, said means operating to give the lever -a further swinging movement thereby to retract the jaws bodily, and means acting on the jaw having the opening to give it a further closing movement thereby to sever the thread.

In testimony whereof, I have signed my name to this specification.

JOHN KIEVICZ.

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