US2426543A - Thread-cutting mechanism for sewing machines - Google Patents

Description

A- R. WOOD .Aug. 26, 1947 THREAD CfiITING MECHANISMS EOR SEWING MACHINES Filed Aug. 21, 1945 3 Sheets-Sheet l 1% m 3. cj zfrd 71/0060 Guam;

A. R. WOOD 2,426,543 THREAD CUTTING MECHANISMS FOR SEWING MACHINES Filed Aug. 21,1945 3 Shgets-She'et '2 Aug. 26, 1947. R. WOOD ,42

I THREAD CUTTING MECHANISMS FOR SEWING MACHINES K Filed Aug. 21, 1945 3 Sheets-Sheet 3 Patented Aug. 26, 1947 THREAD-CUTTING MECHANISM FOR SEWING MACHINES Alfred E. Wood, Bridgeport, Cnn., assignor to The Singer Manufacturing Company, Elizabeth, N. J a corporation of New Jersey Application August 21, 1945, Serial No. 611,723

This invention relates to group-stitching sewing machines, such for example as buttonhole machines or tacking machines, and more particularly to the thread-cutting mechanism of the machine, which mechanism is designed not only to cut the needle-thread close to the work at the end of a sewing operation and hold the beginning end of the needle-thread for the beginning of the next sewing operation, but also to retrim the beginning end of the needle-thread close to the work, so that both ends of the needle-thread will be uniformly trimmed.

In sewing machines of the type to which the present invention pertains, it is customary to provide the upper member of the work-clamp with a combination thread-cutting and -nipping blade which is actuated at the end of the sewing operation to cut and nip the needle-thread. This thread-cutting and -nipping blade holds the beginning end of the needle-thread during the sewing of slightly more than half of the stitching cycle. As the sewing proceed to complete the operation and nears the starting point, this blade is retracted to get it in readiness t0 cut the needle-thread after the stitching cycle is completed. When the blade is retracted, however, it releases the beginning end of the needlethread which, in view of its length, is in a position to be sewed-in or bound down by the final stitches of the buttonhole or tack. In view of this condition, there is a certain lack of uniformity in the product of such a machine result ing from the fact that the beginning end is not disposed of and may at times protrude to an unsightly extent necessitating hand retrimming.

To eliminate the necessity of this hand retrimming, the combination thread-trimming and -nipping blade is operated twice for each complete stitching cycle, once before the sewing is completed, preferably after slightly more than one-half of the stitching cycle is completed, when it is safe to release the beginning end of the needle-thread, and a second time after the sewin is completed. The first operation of the blade retrims the beginning end of the needle-thread and the second operation trims the finishing end of the needle-thread; both ends being thus uniformly trimmed close to the work.

In prior machines, the resetting of the trimmer-blade preparatory to the final threadcuttin and -nipping operation is efiected by utilizing solely the longitudinal shifting of the workclamp relative to the bed of the machine to bring the usual trimmer-blade retracting pushrod carried by the work-clamp into contact with 14 Claims. (Cl. 112252) a fixed abutment member. Inasmuch as the longitudinal shifting of the work-clamp is effected in a step-by-step manner, the resulting relatively slow retraction of the trimmer-blade in a plane perpendicular to the path of needlereciprocation requires that the trimmer-blade be swung beyond the range of the needle before the work-clamp is shifted to a point such that collision can occur between the needle and trimmer-blade. This condition limited the capacity of the machine, since it prevented the machine from producing buttonholes or tacks smaller than a certain size. In an effort to increase the capacity of the machine, the length of the needlethread trimmer-blade was reduced, but this introduced the possibility of the trimmer-blade missing the needle-thread when it was swung to trim the finishing end of the needle-thread.

It is the primary object of the present invention to provide means effecting a rapid retraction of the combination needle-thread-trimming and -nippin blade for the purpose of resetting the blade for its final thread-cutting and -nipping operation.

Another object of the invention is to provide a needle-thread-trimming and -nipping blade retracting mechanism designed to operate with such rapidity that the blade may be swung into its reset position after the blade has been shifted Within the range of the needle.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations, and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodimom; of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings,

Fig 1 is a fragmentary right side elevational view of a straight buttonhole sewing machine equipped with the present invention.

Fig. 2 is a top plan view, partly in section, of the bed of the machine shown in Fig. 1, illustrating the location of the thread-trimming device and the operating mechanism therefor when the machine is performing the first portion of the stitching cycle. I

Fig. 3 represents an enlarged vertical sectional view taken substantially along the line 3-3, Fig. 2, showing the way in which the needle-thread beginning end isheld nipped.

Fig. 4 represents a top plan View, partly in section, of the needle-thread trimmer, illustrating the trimmer-blade in set position preparatory to the retrimming of the beginning end of the needle-thread.

Fig. 5 represents a vertical sectional view similar to Fig. 3, but showing the relatively long released beginning end of the needle-thread.

Fig. 6 is a view similar to Fig. 5, but showing the needle-thread beginning end retrimmed to its final short length.

Fig. '7 is a view similar to Fig. 4, but showing the trimming-blade in its reset position preparatory to its final thread-cutting and -nipping operation.

Fig. 8 represents an enlarged perspective view of the cam-element employed for actuating the trimmer operating mechanism so as to swing the trimmer-blade into its set and reset positions.

Fig. 9 represents an enlarged perspective view of the cam-locking disk which is employed for securing the actuating cam-element in any one of a plurality of selected positions determined by the. length of the buttonhole or tack to be produced.

Fig. 10 represents an enlarged vertical, sectional View taken substantially'along the line l@--lil, Fig. 1.

Fig. 11 represents an enlarged left side elevational view of the trimmer-blade retracting pushrod and its latching expedient.

In the preferred embodiment of the invention, the buttonhole sewing machine illustrated in the drawings comprises a frame including a bed i supporting a standard 2 of an overhanging bracket-arm terminating in a head 3. Mounted in the head 3 is a vibratory gate 4 carrying an endwise reciprocatory needle-bar 5 fitted at its lower end with an eye-pointed thread-carrying needle 9. The needle-bar 5 derives its reciprocation from the usual actuating connections within the head 3, which connections are operated from the mainor arm-shaft (not shown) of the machine. The arm-shaft is connected by a vertical shaft l and gearing 8 to a loop-taker shaft 9 adapted to carry at its outer end a rotary loop-taker (not shown) for cooperation with the needle 9 in the formation of stitches.

The work W to be buttonholed is adapted to be held in a work-clamp comprising the usual lower work-plate ill and an upper clamp-foot I I. The upper clamp-foot H is carried by the two resilient arms i2 and i3 which are secured at their inner ends on a yoke M pivoted at I5 to a lug It upstanding from the longitudinal slideplate ll. The upper clamp-foot H is yieldingly urged downwardly into contact with the lower work-plate Ill by a coil-spring l8. To provide for separating the upper clamp-foot ll from the lower work-plate IQ for the insertion and removal of work, the yoke I4 is formed with a rearwardly extending tail-lever l9 adapted to underlie a roller (Fig. 2) carried intermediate the ends of a manually actuated lever 2i fulcrumed at one end on a stud 22 threaded into the supporting bracket 23. At its other" end, the lever 2| is fitted with a horizontally disposed stud 24 to the free end of which is attached a suitable treadlechain connection-element 25. Depression of a suitable foot-treadle will cause the lever 2! to swing on the stud 22, against the action of a spring 26, thus causing the roller 29 to engage the tail-lever l9 and swing the yoke l4 about its fulcrum l5, thereby raising the arms [2 and i3 and the upper clamp-foot II.

To eifect shifting of the work relative to the endwise reciprocatory and laterally vibratory needle 5, the work-clamp is'slowly moved in stepby-step fashion, first away from the standard 2 and then towards the standard to cause the first and second rows of side zigzag stitches to be laid side by side in the work. The work-clamp derives its step-by-step movements from the usual feed-cam 2'! carried on a Vertically disposed feedshaft'28 journaled in the bed and the bracketarm of the machine. The connections between the work-clamp and the feed-cam are identical with those disclosed in my co-pending applicationSerial No. 545,035, filed July 15, 194A. 'The feed-cam 21 and the feed-shaft 28 are intermittently rotated by means of a one-way-acting clutch 29, of the well-known Horton type, which clutch is driven during the operation of the machine by means of an actuating lever 36 connected by a link 3! to a rock-lever 32 carried by the lower end of a vertically disposed rock-shaft 33 (Fig. 1) journaled in a bearing bushing 34 pressed into the machine-bed I. At its upper end, the rock-shaft 33 has secured to it a second rock-lever 35 connected to a pitman 39 which embraces an eccentric 31 fast on the vertical shaft 1. As the shaft 1 is rotated, the eccentric 31 imparts to the rock-shaft 33 oscillatory movements which, through the rock-lever 32, link 3i and actuating lever 36, operate the clutch 29. The

clutch drives the feed-cam 21 and the feed-shaft 28 intermittently in one direction.

The needle-thread trimming and nipping mechanism now to be described comprises a trimming-blade 38 and a nipping-blade 39 (Figs. 3 and 6), the shanks of which are secured by a screw 49 in a cross-slot ll provided in a head 42 formed at the lower end of the usual vertical rock-shaft 43 journaled in the upper clamp-plate II. This construction is substantially the same as that disclosed in the U. S. patent of E. E. Allen, No. 885,310, dated April 21, 1908. The needle-thread trimming and nipping- blades 38 and 39 are adapted to operate in a slot 44 defined by the under surface 45 of the upper clamp-plate H and the surface 46 of a hardened detachable section 41 secured to'the clamp-plate H. The nipping-blade 39 cooperates with the surface 15, as shown in Fig. 3, to hold the beginning end of the needle-thread during the sewing of the first portion of the buttonhole. The trimmer-blade 38 has a sharpened edge which cooperates with an edge of the surface 45 of the detachable section 41 in severing the needle-thread.

The trimmer-blade carrying rock-shaft 43 has fixed on its upper end a rock-arm 49 connected to the outer end of a trimmer-blade actuating member or retracting push-rod 49 disposed in the direction of the longitudinal travel of the workclamp and endwise slidably supported adjacent its inner end in an upstanding ear 55 integral with a plate 51 secured by screws 52 on the yoke M. The ear 5!], in addition to serving as a support for the push-rod 49, also functions in conjunction'with a fixed collar 53 and resilient pad 54 on the push-rod 49 as a stop to limit the endwise movement of the push-rod under the action of a coil-spring 55 acting between the ear 50 and another fixed collar 56 on the push-rod 49. The coil-spring 55 normally functions to maintain the parts in the position shown in Figs. 2 and 3, in which position the beginning end of the needlethread is nipped and the resilient pad 54 of the collar 53 is against the ear 50.

To produce the necessary endwise movement of the push-rod 49 for actuating the threadtrimming and nipping blades 38 and 39 to effect the release of the nipped beginning end of the needle-thread and to set the trimmer-blade preparatory to the retrimming of the beginning thread-end, there is provided. a cam-actuated linkage. This linkage comprises a lever 51 pivoted at one end on a stud 58 threaded into a lateral extension 59 provided on the supporting bracket 23. The other end of the lever 51 is upturned, as at 99, to engage a block 6| (Fi 4) adjustably secured on the push-rod 49. The lever 51, intermediate its ends, is connected by a link 62 to a second lever 63 pivoted at 34 on the lateral extension 59 and having a cam-follower nose 65 which is maintained by a spring 66 in contact with an actuating cam 6'! integral with an actuating device or cam-element 61 mounted on the feed-shaft 28. The actuating cam 81 is formed with a gradual rise 68' terminating in a sharp drop-01f 69; the timing of the drop-off 69 being regulated through the medium of a timing pin 19 adapted to be yieldingly pressed into a selected one of a number of timing holes H provided in a disk 12 fast on the feed-shaft 28. On the rim of the disk 12, each of the timing holes 7! is identified by a number from one to thirteen, corresponding to a similar number employed on the adjusting device of the mechanism connecting the feed-cam 21 with the work-clamp, which number indicates the length of buttonhole to which the machine is adjusted to produce. For a disclosure of this adjusting device, reference may be had to my above mentioned co-pending application Serial No. 545,035. To efiect an adjustment of the timing of the cam 6'! to con-- form with an adjustment of the work-clamp shifting mechanism, the cam-element 67' is lifted by its knurled hub 13, in opposition to a coil-spring M (Fig. 1), and turned relative to the feed-shaft 28 until the pin 79 is in register with the desired timing hole H, after which the knurled hub 13 is released. The coil-spring M maintains the pin 19 in the selected timing hole H, thus locking the cam-element 61' to turn with the feedshaft 28.

When the machine isstarted, the component parts of thread-trimming mechanism are in the position shown in Fig. 2, with the beginning end of the needle-thread held nipped as shown in Fig. 3. As the sewing progresses down the first side of the ibuttonhole, the feed-shaft 28 is turned slowly, causing the gradual rise 68 of the cam 67 to swing the lever 51, through the lever 53 and link 62, so that its upturned end 99 engages the block 6! on the push-rod 49 and shifts the latter into the position shown in Fig. 4. In this position of the push-rod 49, the trimmer-blade 38 and the nipping-blade 39 have been swung into open position, in which position the beginning thread-end is released as shown in Fig. 5, and the trimmerblade is set for its retrim stroke. As the machine continuesto operate, the cam 61 is turned to the point where its drop-off 69 passes the nose 95 of the lever 63. When this occurs, the coil-spring 55 snaps the push-rod 49 endwise and in a direction to close the trimmer-blade 38 upon and retrim the beginning end of the needlethread to the length clearly shown in Fig. 6.

To provide for reopening or resetting the trimmer-blade 38 preparatory to the trimming of the finishing end of the needle-thread and nipping the beginning end of the needle-thread for the beginning of the next sewing operation, I have provided a second cam-actuated linkage or lever arrangement, the components of which are designed and proportioned to perform its intended function rapidly and efficiently. To this end, the

cam-element 61 is provided with a second actuating cam 15 adapted to engage-a cam-followernose 16 formed on the free end of one of the arms of a two-arm lever 11 fulcrumed at 18 on the machine-standard 2. The other arm of the lever 11 has secured to it a roller 19 arranged to enter an elongated slot 89 formed in the shorter limb of an L-shaped lever 8| fulcrumed at 58 on the lateral extension 59 of the supporting bracket 29. The longer limb of the lever 8| terminates in a downturned end 82 adapted to be moved into engagement with the block BI on the end of the push-rod 49. As will be seen in Fig. 4, the cam '15 is positioned relative to the cam 61 so that shortly following the action of the trimmer-blade 38 in retrimming the beginning end of the needlethread, the cam 15 engages the nose 16 of the two-arm lever 11 and swings said two-arm lever about its pivot 18. The longer arm of the twoarm lever, being operatively connected to the shorter limb of the L-shapedlever 8|, efiects a rapid turning of said L-shaped lever, bringing the downturned end 82 thereof into engagement with the block 6|, thereby shifting the push-rod 49 endwise against the action of the coil-spring 55 and into the position shown in Fig. '7. In this position the trimmer and nipping blades 38 and 39 are open or reset preparatory to the final trimming and nipping of the needle-thread. As shown in Fig. '7, the trimmer and nippingblades 38 and 39 are maintained in reset position by a latch-lever 83 pivoted intermediate its ends at 84 on an upstandin ear 85 formed on a bracket 89 fastened on the yoke [4 (Fig. 10). One end of the latch-lever 83 is biased, by a spring 81, downwardly to cooperate with a stop-notch 88 formed in the collar 53 which is fixed on the push-rod 49.

When the machine is started, the component parts of the thread-trimming and -nipping mechanism are in the position shown in Figs. 2 and 10. In this position, the latch-lever 83 rests upon the push-rod 49 in advance of the fixed collar 53. A the sewing progresses,.the cam 61 and its associated linkage operate to effect a release of the beginning end of the thread and to retrim the released thread-end to the desired short'length. As shown in Fig. 4, the extent of endwise movement imparted to the push-rod 49 to effect this thread-release and -retrim is just short of bringing the stop-notch 88 on the fixed collar 54 into register with the latch-lever 83. Consequently, the latch-lever does not preclude the proper functioning of the mechanism for this operation. Immediately after the retrim of the released thread-end is accomplished, the cam 15 and its associated linkage operate to reset the trimmer-blade 38 preparatory to its final thread trimming and -nipping operation. As shown in Fig. 7 the extent of endwise movement imparted. to the push-rod 49, in opposition to the coilspring 55, is quite sufficient to move the stopnotch 88 on the collar 53 into register with the latch-lever 8-3, permitting the latch-lever under the action of the spring 8! to drop into the notch 88 and lock the trimmer-blade and nipping-blade in reset position.

Means actuated by the work-clamp lifting mechanism are provided for effecting a release of the trimmer-blade 38 and nipping-blade 39 at the end of the buttonholing cycle. Referring to Figs. 1, 2 and '7, it will be seen that the stud 24 carried by the manually controlled work-clamp elevating lever 2|, and to which the treadle chain is connected, extends through a cam-slot,

lie-formed adjacent the :upper end of an intermediate member or rock-lever 9i] pivoted at 9| on the machine-bed l. The rock-lever 90 has connected to it a link 92 having adjustably secured on it a trip-element 93 adapted to cooperate with the latch-lever 83 to lift the same out of the notch 88 when the foot-treadle is depressed to elevate the work-clamp. As shown in Figs. 1 and 2, the link 92 is also connected to one limb of a bell-crank lever 94 disposed beneath the bed I; the other limb of the bell-crank lever being connected to a cross-slide 95 having a rack 96 in mesh with a segmental gear 91 carrying a bobbin-thread trimmer-blade 98. A copending application Serial No. 611,725 filed herewith discloses and claims the constructive features of the illustrated bobbin-thread trimmer. The connections above described function simultaneously to operate both the needle-thread trimmer and the bobbin-thread trimmer. It will be appreciated that the cam-slot 89, in its preferred form, is provided with an actuating portion 89 and a dwell-producing portion 89" so that the link 92 is actuated only during the initial depression of the Work-clamp elevating foot-treadle and during the time that the stud 24 is tracking the actuating portion 89, to insure that both of the sewingthreads are out before the work-clamp is raised to release the work. The trip 93 is adjustably fastened on the link 92 so that the timing of the release of the latch-lever 83 can be regulated. Also, the link 92 is preferably made adjustable, as shown at 99 in Figs. 1 and 2, in order to provide'means for simultaneously regulating the timing of the actual thread-severing of both of the thread-trimming mechanisms.

From the above description taken in connection with the accompanying drawings, it will be appreciated that I have invented an improved meansfor effecting a rapid resetting of the needie-thread trimmingand nipping-blade preparatory to its final thread-trimming and -nipping action. The design of the improved means is such that its quick action is inherent. In addition, th cam for actuating the improved means is set" so that it does not function until the stitches forming the return side of the buttonhole are being produced. This is desirable for the reason that'during the formation of the stitches on the return side of the buttonhole,

the work-clamp is moving toward the standard of the'machine, while the free end 82 of the lever 81 is moving away from th standard toward the approaching work-clamp. This simultaneous movement of the Work-clamp and lever toward each other augments the inherent quick action of my improved resetting means, the result of which is an extremely rapid retraction of the trimmer-blade, whereby collision between the trimmer-blade and the needle is avoided when a long trimmer-blade is employed and the machine is set to sew short buttonholes approximatel /4 in length.

Having thus set forth the nature of the invention, what 'I claim herein is:

1'. In a group-stitch sewing machine, in combination, stitch-forming mechanism, a traveling work-clamp, a needle-thread-cutting and -nipping device, actuating means therefor includ ing a reciprocatory element supported by and normally partaking of the movements of the work-clamp, a first means comprising a cam actuated linkage adapted for engagement with said-reoiprocatory element and effective for opening and then closing said' thread-cutting and -nipping device to release and then retrim the beginning end of the needle-thread, a second means comprising another camactuated linkage adapted for engagement with said reciprocating element and effective for reopening said thread-cutting and -nipping device preparatory to its final nipping and cutting action, and means for effecting a final closing of said thread-cutting and -nipping device to nip and sever the needle-thread at the completion of the sewin operation.

2. In a group-stitch sewing machine, in combination, stitch-forming mechanism, a traveling work-clamp, a thread-cutting device, actuating means therefor including a reciprocatory element supported by and normally partaking of the movements of the work-clamp, means adapted for engagement with said reciprocatory element and effective for moving said thread-cutting device into open position, said means including a first pivotally mounted lever having one of its ends disposed to engage and actuate said reciprocatory element, a second pivotally mounted lever operatively connected with said first lever, and means for actuating said levers Whereby the first lever moves simultaneously with and opposite to the travel of said work-clamp in actuating said reciprocatory element, and means for effecting a closing of said thread-cutting device at a predetermined time during the groupstitch cycle.

3. In a group-stitch sewing machine, in combination, a machine-frame, stitch-forming mechanism adapted for interlocking an upper thread and a lower thread, a work-clamp, means including a manually controlled lever for opening said work-clamp for the insertion and removal of work, a thread-cutting device for said upper thread and a thread-cutting device for said lower thread, a member movably mounted on said machine-frame and having a cam-slot, means on said manually controlled lever cooperating with said cam-slot for imparting movement to said member when said lever is actuated, and a connection with said member disposed to effect the operation Of both of said thread-cutting devices during the initial movement of said manually controlled lever and prior to the opening of said work-clamp.

4. In a group-stitch sewing machine, in combination, a machine-frame, stitch-forming mechanism adapted for interlocking an upper thread and a lower thread, a work-clamp, means including a manually controlled lever for opening said work-clamp for the insertion and removal of work, a thread-cutting device for said upper thread and a thread-cutting device for said lower thread, a member movably mounted on said machine-frame and having a cam-slot provided with an actuating portion and a dwell-producing portion, means on said manually controlled lever cooperating with said cam-slot for imparting movement to said member during the traversing of the actuating portion of said cam-slot, and a connection with said member disposed to effect the operation of both of said thread-cutting devices during the actuation of said member.

5. In a group-stitch sewing machine, in combination, a machine-frame, stitch-forming mechanism adapted for interlocking an upper thread and a lower thread, a work-clamp, means including a manually controlled lever for opening said Work-clamp for the insertion and removal of work, a thread-cutting device for said upper thread and a thread-cutting device for said lower 9 thread, a member movably mounted on said machine-frame and having a cam-slot provided with an actuating portion and a dwell-producing portion, means on said manually controlled lever cooperating with said cam-slot for imparting movement to said member during the traversing of the actuating portion of said cam-slot, a connection with said member disposed to effect the operation of both of said thread-cutting devices during the actuation of said member, and means for simultaneously regulating the timing of the thread-severing of both of said thread-cutting elements.

6. In a group-stitch sewing machine, in combination, a machine-frame, stitch-forming mechanism adapted for interlocking an upper thread and a lower thread, a Work-clamp, means including a manually controlled lever for opening said work-clamp for the insertion and removal of work, a thread-cutting device for the upper thread and a thread-cutting device for the lower thread, a member movably mounted on said machineframe and having a cam-slot provided with an actuating portion and a dwell-producing portion, means on said manually controlled lever coopcrating with said cam-slot for imparting movement to said member during the traversing of the actuating portion of said cam-slot, a connection with said member disposed to effect the operation of both of said thread-cutting devices during the actuation of said member, and means for regulating the time of thread-severing of one of said thread-cutting devices relative to the time of thread-severing of the other of said thread-cutting devices.

7. In a group-stitch sewing machine, in combination, a machine-frame, stitch-forming mechanism, a work-clamp, means including a manually controlled lever for opening said work-clamp for the insertion and removal of work, a thread-cutting device, means for opening said thread-cutting device, a latch for maintaining said threadcutting device in open position, a member movably mounted on said machine-frame and having a cam-slot provided with an actuating portion and a dwell-producing portion, means associated with said work-clamp opening means and cooperating with said cam-slot for imparting movement to said member during the traversing of the actuating portion of said cam-slot, and a connection with said member disposed to trip said latch during the actuation of said member whereby said thread-cutting device is released to close into effective thread-severing position.

8. In a group-stitch sewing machine, in combination, a machine-frame, stitch-forming mechanism adapted for interlocking an upper thread and a lower thread, a work-clamp, means including a manually controlled lever for opening said work-clamp for the insertion and removal of work, a thread-cutting device for said upper thread and a thread-cutting device for said lower thread, a member movably mounted on said machine-frame and having a cam-slot provided with an actuating portion and a dwell-producing portion, means On said manually controlled lever cooperating with said cam-slot for imparting movement to said member during the traversing of the actuating portion of said cam-slot, said actuating portion of the cam-slot being disposed so that said member is shifted the full extent of.

its movement before said work-clamp is opened sufficiently to free the Work, and a connection With said member disposed to eifect the operation of both of said thread-cutting devices during the actuation of said member. s;

9. In a sewingmachine, in combination, stitch; forming mechanism, a workc1amp,j feeding means for relatively moving the'stitch-forming; mechanism and the work-clamp to sew a group of stitches, said feeding means including an actuating feed-shaft, a needle-thread-cutting and -nip-;- ping device, an actuating member operatively associated with said needle-thread-cutting and- -nipping device, a first means actuatedfrom said feed-shaft for engagement with said actuating member for opening and closing said thread-cutating and -nipping device to release and then-re-- trim the beginning end of the needle-threadja second means also actuated from said feed-shaft for engagement with said actuating member for reopening said thread-cutting and -nipping device preparatory to its final nipping and cutting action, and means permitting a final closing of.

said thread-cutting and -nipping device to nip and sever the needle-thread at the completion of the sewing operation. i

release and then retrim the beginning end o f'the needle-thread, a second means adapted to engage said actuating member for reopening said thread-T; cutting device preparatory to its final nipping, a d cutting action, a single actuating'device secured. on said feed-shaft for operating said firstandf second means in series, and means permittinga, final closing of said thread-cutting and .-'nipping device to nip and'sever the needle-thread at the,

completion of the sewing operation.

11. In a sewing machine, in combination,"

stitch-forming mechanism, a work-clamp, feeding means for relatively moving the stitch-forming mechanism and the work-clamp to sew a group of stitches, said feeding means including a feed-shaft and connections for varying the extent of the relative movement between the stitchforming mechanism and the work-clamp, a needle-thread-cutting and -nipping device, an actuating member operatively associated with said needle-thread-cutting and -nipping device, a first means adapted to engage said actuating member for opening and closing said thread-cutting and -nipping device to release and then retrim the beginning end of the needle-thread, a second means adapted to engage said actuating member for reopening said thread-cutting and -nipping device preparatory to its final nipping and cutting action, an actuating device for operating said first and second means in series, means for regulating the effective position of said actuating device to conform with the selected position of adjustment of the connections for varying the extent of relative movement between the stitchforming mechanism and the Work-clamp, and means for permitting a final closing of said thread-cutting and -nipping device to nip and sever the needle-thread at the completion of the sewing operation.

12. In a sewing machine, in combination, stitchforming mechanism, a work-clamp, feeding means It for relatively moving: me stitch-forming media nism and the work-clamp to sew a group of stitches, said feeding means includingan actuating feed-shaft, a needIe-thread-cutting and -nipping device, anactuating member operatively associated with said needle-thread-cutting and nipping device, afirst' means adapted to engage said actuating member for opening and closing said thread cutting. and -n ippin'g device to release and their retrim the beginning end of the needlethread, a} second means adapted to engage said actuating member for reopening said-thread-cutting device-preparatory to its final nipping and cutting action, anactuating device secured on saidfeed-shaft and having a plurality of cam-- sections disposed tooperate said first and secand means in series, and means permitting a final closing of said thread-"cutting and -nipping device to nip and sever theneedle-thread at the completion of the sewing operation. 7

1-3. In a; sewing machine, stitch-forming mechanisi-n, a work-clamp, feeding means for relatively moving the stitch-forming mechanism and the work-clamp to sew a group of stitches,- said feeding means including a feedsh'af-t and connections for varyingthe extent of the relative movement between the stitch-formmg mechanismand the work-clamp, a needletliread cutting' andf -nipping device, an actuating member operatively associated with said ne'e'd1e opening and closing said thread-cutting and -nipping device to release and then retrim the beginning end of the'needle-thread, a second means adapted to engage said actuating member for reopening said thread-cutting and -nipping device preparatory to its final nipping and cutting action, anactuating device provided with a plurality of cam-sections disposed to operate said first" and second means in series, said actuating device being mounted on said feed-shaft and secured thereto by means permitting regulation of the effective position of said cam-sections to in comblnation,

, thread-cutting and -nipping device, a first means 1 adapted" to engage said actuating member for conform with the selected position of adjustment of the connections for varying the extent of relative movement between the stitch-forming mechanism and the Work-clamp, and means for permitting a final closing of said thread-cutting and -nippingdevice to nip and sever the needlethreadat the completion of the sewing operation.

14. In a group-stitch sewing machine, in combination, stitch-forming mechanism, a traveling Work-clamp, a thread-cutting device, an actuat ing member operatively associated with said thread-cutting device and supported by the normally partaking of the movements of the workclamp, means adapted for engagement with said actuating member and eftective for moving said thread-cutting device into open position, said means including a first pivotally mounted lever having one of its ends disposed to engage and operate said actuating member, a second pivot- -al1y mounted lever connected to said first lever,-

and a cam device engaging said second lever in a manner to move said lever simultaneously with and opposite to the travel of said work-clamp in operating said actuating member, and means for effecting a closing of said thread-cutting device at a predetermined time during the machine cycle.

ALFRED R. WOOD.

REFERENCES orrEn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name 'Date 1,920,944 Wood Aug. 1, 1933 1,955,994 Wood Apr. 24, 1934 1,404,727 Allen Jan. 31, 1922 1,325,707 Wood Deck 23, 1919 1,369,371 Allen Feb. 22, 1921 1,912,056 Almond et al. May 30, 1.933 1,930,637 Allen Oct. 17, 1933 1,016,027 Mills Jan. 30', 1912

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