US1542764A - Thread-trimming device for buttonhole-sewing machines - Google Patents

Description

June 16, 1925.

J. W. CONNORS THREAD TRIMMING DEVICE FOR BUTTONHOLB SEWING MACHINES Filed Dec. 26, 1924 4 Sheets-$heet 1 lnvenTor. John W. Connors byimawk June 16, 1925. v 1,542,764 J. w. CONNORS THREAD TRlMMING DEVICE FOR BUTTONHOLE SEWINGMACHINES Filed 1139.9. 26, 1924 4 Sheets-Sheet 2 Uohn Connors b yiuwl Muf AIMS.

June 16 1925.

J. W. CONNORS THREAD TRIMMING DEVICE FOR BUTTONHOLE SEWING MACHINES Filed Dec. 26,

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Patented June 16, 1925.

v UNITED STATES 1 r 1,542,764 TENT OFFICE.

7 JOHN W. CONNOR-S, OF DEDHAM, MASSACHUSETTS, ASSIGNOR I'D THE REECE BUTTON HOLE MACHINE MAINE.

THREAD-TRIMMING DEVICE FOR BUTTOZNHOLE-SEWING MACHINES.

Application filed December 26, 1924. Serial No. 758,105.

To all whom it may con-am:

Be it'known that I, JOHN W. CoNNons, a citizen of the United States, and resident of Dedham, county of Norfolk, State of Massachusetts, have invented an Improvement in Thread-Trimming Devices for Buttonhole-Sewing Machines, of which the following description, in connect-ion'with the rectly from the main cam of the machine,

Other objects of the invention are to improve generally thread cutters all as will be morefully hereinafter set forth.

In the drawings wherein I have illustrated a selected embodiment of the invention,

, Fig. 1 is a side view of a buttonhole sewing Y machine embodying the invention;

Fig. 2 is a plan View of the bed, frame showing the head removed and illustrating the thread cutter and its actuating mechanism. I

Fig. 3 is an under side view of the bed frame.

Fig. 4: is a fragmentary view similar to Fig.2 but showing the-cutter in thread cutting position;

Fig. 5 1s a section on the line.55, Fig. 2; Fig. 6 is a section on the line 6-6, Fig. 2;

Fig. 7 is a fragmentary front view of thev bed plate" showing the cuttenactuating mechanism. a

In the machine herein shown 1 indicates the bed frame of the machine which supports the usual overhanging arm or head 2 in which the needle bar 3 of the upper needle 4 reciprocates.

Situated beneath the bed plate is the under thread handling mechanism which, in the construction herein shown, is mounted on a rotary turret 5.

The work in which the buttonhole is to formed is held in a work holder comprising a clamp plate 6 on whichthe work is sup- [ported and workclamps 7 which clamp the Work aganist the clam'p late 6.. This work holder is movable back and forth on the bed the buttonhble and thenback along the other side of the buttonhole, after which the work holder is given a further movement to return the work to buttonhole-cutting position.

8 indicates the usual buttonhole cutter. 9 indicates the usual main cam which is situated underneath the bed plate and by which the operations of the machine are controlled. The parts thus far described are or may be all as usual in buttonhole sewing machines and form 110 part of the present invention which relates to the thread cutter for trimming the thread beneath the work and'between the latter and the clamp plate 6. This thread cutter is in the form of a swinging member 10 pivoted at 11 to an extension 12of the clampplate 6, said cutter having a reentrant cutting edge 13 which co-operatcs with the shearing edge let of a shearing block 15- securcd to the clamp plate 6.

The cutter is shown in mal' posit-ion which it occupies during the stitching operation and when the thread is to be cut at the end of the stitching operation said cutter which is beneath the work, isswung to the right Fig. 2 into the position shown in Fig. 4. Duringthis movement the under thread which leads from the work and also the loop of upper thread leading from the under side of the work around the looper and back through the work again. are caught by the reentrant cutting edge 13 and are carrled against the shearing edge 14, andare thus cut. In

"practice aguard plate is employed to cover the cutter, said guard plate forming the support on which the work restsand, being provided with an opening through which the threads extend.

16 indicates a yielding hold down which holds the cutter in shearing engagement COMPANY, or BOSTON, MASSACHUSETTS, A CORPORATION or ment by mechanism actuated from the main cam 9. Pivoted to the clamp plate 6 at 17 is an actuating lever 18 which is formed with an extension 19 having a slot 20 there in in which slot is received a pin 21 secured to the cutter. The swinging movement of the member 18 will thus give a swinging movement to the cutter as will be obvious. The actuating member 18 projects beyond the front edge of the bed frame as shown at 22and said projecting portion n2 is adapted to be engaged by a projection 23 rising from a slide 24 which is movable transversely across the bed frame. This slide 24 is mounted for reciprocating movement in a. guide member 25 that is secured tojthedepending flange 26 of the bed frame. The projection 23 may conveniently have an anti-friction roll 27 thereon to reduce the frictional engagement, with the projecting portion 22 of the member 18.

The member 18 is norn'ia-lly held in its retracted position shown in Fig. 2 by means of a spring 28 herein shown as apulling spring connected at one end to the clamp plate 6 as shown at 29 and connected at its other end to the end of an arm 30 which is secured to and extends laterally from the member 18.

The slide 24 is shown as having a pin or projection 31 depending therefrom which operates in a slot 32 in one arm 33 of an elbow lever 34, the latter being pivoted at 35 to the under side of the bed frame 1. The arm 36 of the elbow lever has a pin and slot connection with a sliding bar 37 which extends longitudinally of the bed frame and operates in, a slot 38 formed therein. The other end of the bar 37 is pivotally connected to a lever 39 which is pivoted to the bed frame at 40 and which is adapted to be engaged and actuated by a roll 41 carried by the main cam 9.

The lever 39 is located on the upper side of the bed frame 1 and the inner end of said lever has the depending portion 42 which extends through an opening 43 formed in the bed frame, the lower end of said depending portion having the cam face 44 adapted to be engaged by the roll 41 as the cam 9 rotates.

The slide bar 37 is acted upon by a spring 145which tends normally to hold the parts in the position shown in Fig. 3.

The engagement of the roll 41 with the cam face .44 will swing the lever 39 into the dotted line position Fig. 2, and this movement ofthe lever will operate through the slide bar 87 and elbow lever 34 to actuate the slide 24 thereby to carry the roll 27 against the extension 22 of the actuator 18 and swing the latter to the right Fig, 2 which will operate to give the knife its th read -tri i nn1ing 'movement.

As the r911 41 Wipes ofi from the cam 44 the springs 145 and 28 will return the parts to their normal position shown in Fig. 2.

Sewing machines of this type are commonly so constructed that the main cam will make one complete revolution during each sewing cycle, the machine coming to rest automatically at the end of the cycle. The roll 41 is so situated on the cam. 9 that it will engage the cam face 44 after the sewing on the buttonhole has been completed and while the work holder is moving from stitching to buttonhole cutting position. The trimming of the thread will, therefore, be accomplished directly after the completion of the buttonhole.

Another feature of the present invention relates to means for ensuring that the cutter will be returned to its normal position shown in Fig. 2 after the cutting operation. This is accomplished by providing the projecting end 22 of the actuating lever 18 with a depending flange 45 and providing the slide 24 with an extension 46 having an up-turned flange 47. During the time that the work holder is in stitching position it is in the position illustrated in Fig. 2.

The movement of the work holder from stitching to bnttonhole cutting position is a backward movement; (which is an upward movement looking at Fig. 2) and during this movement the depending flange 45 is carried into juxtaposition to the up-turned flange 47 as shown in Fig. 4. At this time the flange 47 is behind the flange 45 and, therefore, during the return movement of the slide due to the action of the spring 1-15 the upstanding flange 47 will engage the depending flange 45 and positively return the member 18 to its normal position in case the spring 28 fails to do so. Since this member 18 is connected to the cutter through the pin 20 and slot 21 the cutter is positively returned to its normal position thus preventing danger of its sticking and remaining in its thread-cutting position.

The swinging movement of the member 18 limited by a stop pin 51 operating in a slot formed in said member,

The lever 39 is shown as adjustably connected to the slide 37. This adjustment is provided for by pivoting the lever to a block 52 as shown at 53 and adjustably connecting the block to the slide by means of the screw 54. The block 52 is shown as having a slot in which the screw 54 opcrates.

Vvhile I have illustrated a selected embodiment of my invention I do not wish to be limited to the constructional features shown.

I claim. i

1. In a sewing machine, the combination with a bed frame, of work-holding means carried thereby, stitch-forming mechanism, a main cam by which the operation of the 2. In a sewing machine, the combination with a bed frame, of work-holding means,.

stitch-forming mechanism, a main cam by which the operation of the machine is controlled, a thread cutter carried by the workholding means, a slide carried by the bed frame and movable transversely thereof and adapted by its movement to actuate the thread cutter, and means to actuate the slide by the rotation of the main cam.

3. In a sewing machine, the combination with a bed frame, of work-holding means movably mounted thereon, stitch-forming mechanism, a main cam for controlling the operation of the machine and giving the work-holding means its movement, a thread cutter carried by and movable with the work-holding means, a slide mounted on the bed frame and adapted by its movement to actuate the thread cutter, and means to actuate the slide from the main cam.

4. In a sewing machine, the combination with a bed frame, of work-holding means movably mounted thereon, stitch-forming mechanism, a main cam for controlling the operation of the machine and giving the work-holding means its movement, a thread cutter carried by and movable with the work-holding means, a slide mounted on the bed frame and movable transversely thereof, said slide by its movement actuating the thread cutter, and means to' actuate the slide from the main cam.

5. In a sewing machine, the combination with a bed frame, of work-holding means movably mounted thereon, stitch forming mechanism, a main cam by which the workholding means are moved on the bed frame,

a pivoted thread cutter carried by the work holding means, a slide on the bed frame movable transversely thereof and adapted by its movement to operate the cutter, a second slide movable longitudinally of the bed frame and connected to the first-named slide, and means to actuate the second slide by the .cam.

6. In a sewing machine, the combination with a bed frame, of work-holding means movably mounted thereon, stitch-forming mechanism, a main cam by which the workholding means are moved on the bed frame, a pivoted thread cutter carried by the workholding means, a slide on the bed frame movable transversely thereof and adapted by its movement to operate the cutter, a second slide movable longitudinally of the bed frame, an. elbow lever connecting the slides, a cam lever pivotally connected to the second slide and having a cam surface, and a roll carried by the maincam toengage said surface.

7, In a sewing machine, the combination with a bed frame, of work-holding means movably mounted thereon, stitch-forming mechanism, a main cam by which the operation of the machine is controlled, a thread cutter movably carried by the workholding means, a slide movably mounted on the bed frame, means to operate the slide in one direction from the main cam, the

.cam operated movement of the slide giving name to this specification.

JOHN XV, CONNORS.

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