US1822639A - Thread-cutter operating mechanism for sewing machines - Google Patents

Description

Sept. 8, 1931. E. B. ALLEN 1,822,639

THREAD CUTTER OPERATING MECHANISM FOR SEWING MACHINES Filed June 27, 1950 5 Sheets-Sheet 1 il.. Sq

Sept. 8, 1931. E. B. ALLEN 1,822,639

THREAD CUTTER OPERATING MECHANISM FOR SEWING MACHINES Filed June 27, 1930 5 Sheets-Sheet 2 gmmtoz Edlund Alle/z Muna.'

Sept. 8, 1931. E. B. ALLEN 1,822,539

THREAD CUTTER OPERATING MECHANISM FOR SEWING MACHINES Filed June 27, 1930 5 Sheets-Sheet 5 gwoentoz Sept. 8, 1931. E. B. ALLEN 1,822,639

THREAD CUTTER OPERATING MEGHANISM FOR SEWING MACHINES Filed June 2'7, 1930 5 Sheets-Sheet 4 Edward Alle I WE@ E. B. ALLEN Sept. 8, 1931.

THREAD CUTTER OPERATING MECHANISM FOR SEWING MACHINES 5 sheets-sheet 5 Filed Jupe 27, y1930 Edd/afa ZZeM Patented Sept. 8, 1931 UNITED STATES PATENT OFFICE EDWARD B. ALLEN, OF NEWTOVVN, CONNECTICUT, SSIGNOR TO THEV SINGER MANU- FACTURING COMPANY, OF ELIZABETH,

JERSEY' NEW JERSEY, A CORPORATION OF NEW THREAD-CUTTER OPERATING MECHANISM FOB SEWING MACHINES Application filed June 27,

This invention relates to sewing machines and more particul arly to sewing machines of the straight buttonholc type having a stopmotion device for controlling the period of operation ot the stitch-forming mechanism nd also having an upperthread nipper and cutter mounted on the work-clamping foot, as represented in the Allen Patent No. 885,- 310.

V-Vith a machine of this character, the stopmotion device must stop the machine with the upper-thread take-up at its highest point, so that, when the machine is again started, the upperor needle-thread will not be broken or pulled out of the nipper and so that the first stitch will be properly and 'fully tightcned. When the take-up is at its highest point, however, the needle has executed the first part of its down-stroke and, while it has not reached the path of the upper-thread-cutter, there is danger that, as it dips further during` the overthrow motion or motion of compression of the usual stop-motion butterspring, its point may reach the path of the thread-cutter and be blunted by interference with this cutter which is customarily tripped into action by the rip-motion of the stopplunger into the notch ot the stop-cam immediately preceding the overthrow motion or motion of compression of the usual bufferspring. In other words, in the machine referred to, the needle-thread cutter is exe` cut-ing its closing or thread-cutting and -nipping movement simultaneously with the down movement ot' the needle permitted by the overthrow or butler-compressing movement of the machine incident to the operation of the stop-motion device. Hence the danger of interference by the needle in dipping into tl e path ot the thread-cutter.

The present invention has for an object to eliminate the danger of blunting the needle by interference with the upper-thread cutter.

`With the above and other objects in view, as will hereinafter appear, the invention consists in the devices, combinations and arrangements of parts herein after set forth and illustrated in the accompanying drawings of a preferred form of the invention, from which the several features of the invention and the 1930. Serial No. 464,177.

advantages attained thereby will be readily understood by those skilled in the art.

In the accompanying drawings, Fig. l is a side elevation of a buttonhole sewing machine embodying the invention. Fig.. 2 is a horizontal secion through the bracket arm standard .of the machine, showing the ma chine-bed in plan. Fig. 3 is a bottom plan view of a portion of the machine-bed. Fig. 4 is a transverse vertical section through the machine bed on the line 4 4, Fig. 2. Fig. is a rear end elevation of the machine. Fig 6 is a detail view of an element of Fig. 5. Fig. 7 is a disassembled perspective view of the stop-cam and buffer spring mechanism of the stop-motion device. Fig. 8 is a view illustrating the upper thread-cutter tripping mechanism with the parts in their respective positions occupied as the stop-motion plunger enters the notch in the stop-cam and before there is any overthrow or buiier-compressing motion of the machine parts. Fig. 9 is a similar view showing the part-s in full lines at the end of the overthrow motion of the machine parts and, in dotted lines, the movement imparted to the needle thread-cutter release mechanism by the recovery or return motion of the buffer mechanism, following the overthrow or buffer-compressing action of the stop-motion mechanism. Fig. l() is a face view of the needle-bar reciprocating and take-up actuating mechanism, and Fig. 1l, is a fragmentary top-plan view of the tension-release mechanism.

rThe machine illustrated comprises a bed 1, standard 2, overhanging bracket-arm 3 and head 4 in which is journaled the reciprocating and laterally vibrating needle-bar 5 carrying the needle 6. The needle-bar 5 is operated by the usual connections with the main-shaft 7. Cooperating with the needle 6 below the bed l is the usual oscillatory shuttle S, and the needle-thread loops are drawn up and tightened by means of the usual link take-up 9. As shown in Fig. l0., a take-up of this character comprises a bell-crank lever 9 which at its lower end embraces a crank-pin l() on the main-shaft 7 and is pivotally connected at 11 to an anchor-link 12. The take-up actuating crank-pin 10 commonly is angularly offset from and lags behind the needle-ber-operating` crank-pin 13, so that when the take-up thread-eye 14E is at its highest point, Figs. 1 und 10, the needle-bar 5 has executed the lirst part of its down-motion.

The machine comprises the usual Workclamp including the cross slide-plate 15 in which is mounted the longitudinal slide-plate 1G carrying; the tulcruni-support 17 for the upper clamp-lever 18 which at its foriva rd end carries thc clump-toot 19. During` the sewine' operation the Work-clamp is moved over the bed ll to place the stitches in the desired order or arrangement around the luittonliole by the usual connections (not shown) with the feed-caln- grooves 20 and 20, Fig. 1, in th e feed-wheel 2O which is 1steered to the inainshatt 'l' and inakes one complete revolution per buttonhole-producing cycle.

llflounted in the upper clamp-toot 19 on the short vertical shaft 21 are the usual needlethreud cutter and nipr r blades 22 which are arranged to sweep horizontally across the needle-path or lead oi: the needle-thread at the close oit a sewing period to cut an d hold the needle-thread in the manner disclosed in said lrllen Patent No. 885,810. The shaft 21 carries a crank-erin 23 to which pvotally connected ay ber 24 slidably supported neer its reni' end in the bracket 25 and cneroized by the spring; 25. Fig. 2, to close 1the tln'ead-cutter and -nipper blades. llfhen sewing); down the return side oit' the buttonhole. the rod 24 which is moving' endvvise of itselic in rearward direction encounters the usual latch-arm 27 and has its inotion arrested While the continued rearward inotion ol the vvork-clan'ip opens the thread-cutter. lVhen the serving; is conuileted, the parts are in the po` ons shown in Fie'. 2 and the thread-cutter 22 is held open bv the latch-arno 27 which is tit-ted to the horizontally disposed rockshett 28 mounted at one side of the standard 2 and conunon to machines ot this type. Actnation ot the rock-shaft 28 Will therefore serve to reise the laten-erin 2T to dotted line position, Fig. fl, and release the needle-thread cutter 22.

The rock-shaft 28 also has tired thereto the bent erin Figs. 1 and 4i, the forked front end which embraces the rearward end of the erin il() lived to the tension-release rockshalt 81 cerryino; the Wedge-pointed arin Fier. 1l., Vtor relcusinfthe dra@ of the tension-device 88 upon the needle-thread. The Wedge-pointed arm 82 is arrene'ed close to the limoen-disks 88 so thet. when the rocksbalzi: is operated, the tension-device Will be opened before the thread-cutter sind -ni nner 22 is releesed, whereby slack needlethread is provided to be drown bv the movable cutter and nipper bled-es into Dipped position hetvreen such movable blades end the usuel stationary upper nipper member not shovni)` common to a thread-cutter and -uippcr ci this type, as shown in said Allen utent No. 885,810.

lrlounted loosely on the rock-shaft 28 a bell-crank lever 84., 35, the arni of which entends dovmwardly through an aperture 36 in the bed 1 sind is connected as usual to actuate the wider-thread cutter and pull-ott' operating); lever 3T, substantially as shown in said Patent No. 885,810. The arn'i 85 of the bell-crank lever has an aperture at its free end tor connection with the usual pedal-operated clamp-lifting chain (not shown). There is also connected at 88 to the bell-crank lever arm 3 a vertical rod 39 which is guided at its lower end in the bracket Ll() and carries the Work-clamp lifting" roller 1-1 disposed ahovc and adapted to depress the tail 18 of the upper Work-clamp lever 18 to raise the clamp-'toot 19 for release of the Work. The vertical rod 89 has a notch ,l2 in one side :ulaixited to he entered by one end of the lockine' lever t8 the other end of which is formed with an upf-tending lip lt in the path ol movement et the louer end ot a curved arm fixed to the rock-shaft 28. Then the niachine is sewing', the lever -18 is in the notch l2 ot the rod 80 und the bell- crank lever 34, 35 is locked aeainst movement. by the operator. lt ie ruilocked by the saine rocking` inoveinent ot the shaft 28 which releases the needlethread-cutter und opens the tension-device.

The stop-motion device Ylor controlling; the period ot operation ot the stitch-l'oriningv mechanism is preferably constructed substantially in accordance With the disclosui'e of' the Allen and Myers application, Serial No. 272,416. liled Apr. 24.1. 1928. The main-shaft i has fixed to it the `egear fl-G which drives the ,Q'ear if? et half speed. The shaft also carries the usual tight and loose belt-pulleys 48. 9..respect-ively. The /17 constitutes a housing; for the buffer- springs 50, 51 disposed between the abutment 52 iXed Within and to the gear L17 and the block 53 disposed within und relative to which the gear l? is .tree to move to a limited extent. The block is connected to the pin 54.- on the stop-cani 55 loose on the bearing stud 55 on which the ,gear l? is journeled.

Cooperating' with the stop-cani 55 is the usuel vertically spring-pressed plunger 56 mounted in the tilting stop-motion lever 57 which includes the usual belt-shipper erin 58. The present stop-cani 55 is of duplex construction, that is, it has tvvo diainctrically opposed stop-notches 59 and tivo plungerdepressing eccentric portions 60. The stopniotion lever 57 is held in its tilted or runnine; position, Fie: 1, by the usual 'feed-canecontrolled latch-lever 51 Which enters a notch 5l in the side of' the vertically spring-pressed latch-rod 62 connected at its upper end to the arm 68 rinid with the stop-motion lever 57. When the tripping1 point (S4 on the toedcani 20 trips the hitch G1, the stop-motion lever 57 will spring to its vertical or dotted line position, Fig. 1, in which positie-n `the-upper end ot' the plunger bar 56 will be engaged by one of the eccentric portions 60 of the stop-cam 55 and depressed, after which the plunger'- bar 56 will be projected upwardly by its spring into the succeeding stop-notch 59 and arrest further movement of the cam 55.

The main-shaft 7 oi the machine and the parts connected thereto and driven thereby have momentum at this time and, to avoid excessive shock, provision is made for an overthrow or momentum absorbing motion of the main-shaft and gear 47 after the stop-cam is locked in stopping position by the stopmotion plunger 56. rhis overthrow motion oithe gear 47 causes the abutment 52 to compress the butler-spring 51 against the then stationary abutment-block Following the overthrow motion of the gear 47 is a recovery motion of said gear in a reverse direction to the final stopping position or position of rest of the main-shaft 7.

According to the present improvement, advantage is taken ot this reverse or recovery motion of the parts following the overthrow or buffer-compressing motion ot' the mainshaft and connected parts to trip the upper or needle-thread cutter, open the tension device, unlock the work-clamp or perform any desired operation auxiliary to the sewing operation, t-he time of which auxiliary operation it may be desirable to delay as late as possible in a buttonhole producing cycle.

To this end a novel mechanism actuated by the recovery motion of the gear 47 is provided or imparting a rocking impulse to the sha tt 28 which heretofore has customarily been rocked by the 11p-motion of the plunger bar 56 into the stop-notch of the usual stopcam. FiXed to the rear end of the rock-shaft 28 is the arm 65 having pivoted thereto at 66 a follower element comprising a lever 67 the upper end ot which is formed with a hoolishoulder 68 disposed in the plane of the actuato-r cam-plate 69 which is fixed by screws 79 passing through arcuate slots 71 in the camplate 69 to the cover-plate 72 for the bufferspring` cavity in the gear' 47; the cover-plate 72 being screwed to the internal hub 73 of the gear 47. The cam-plate 69, which is'thus a iiXed part of the. gear 47, is formed with diametrically opposed shoulders 74 with one or the other oi which the hook-shoulder 68 cooperates on the recovery motion of the gear 47 to rock the shaft 28.

The lever 67 which is normally urge-d toward the cam-plate 69 by the spring 75 is hel d in retracted or inactive position, out of engagement with the cam-plate 69, Figs. 2 and 5, by the side pressure tlhereagainst ot the head 76 of the pin 77 fixed to the tilting stop-motion lever 57. When the stop-motion lever 57 springs to vertical or stopping position, the head 76 of the pin 77 is carried out of engagement with the lever 67 which is tree to be swung by its spring 75 into the -reduced neck 78 of thel pin 77, whereby the upper end of the lever 67 is carried into engagement with the edge of the cam-plate 69, as shown in Fig. 8.

The shoulders 74 are so timed on the gear 47 that when one of the stop-notches 59 of the stop-cam is engaged by the stop-motion plunger 56, at which time the overthrow or builer-compressing motion of the partsy begins, one of the stop-shoulders 74 will be near the hook-shoulder 68 on the lever 67, asshown in Fig. 8. At this time, the take-up 9 is at its highest point and the needle 6 has executed the iirst part of its down-stroke and is moving downwardly under the momentum or buffer-compressing or overthrow-motion of the parts. J ust before this overthrow-motion is completed, the shoulder 74 is 'carried past the hook-shoulder 68 which latter moves inwardly or hooks over the shoulder 74, as shown in Fig. 9, which represents the parts at the end of trie overthrow motion or the beginning oi the reverse or recovery motion, during the execution of which reco-very motion the needle of the sewing machine is moving upwardly or away from the path of the needle-thread cutter and the arm 65 is being lifted to dotted line position and imparts the desired rocking impulse to the shaft 28.

lVhen the recovery motion is spent, the main-shaft 7 will have returned to the same position it occupied when the stop-motion plunger 56 first entered one of the stop-cam notches 59. The take-up will be at its highest point. During the last part of the rocking` movement of the shaft 28, the latch 27 is raised out of engagement with the needlethread cutter-control rod 24, thereby releasing said rod at a time when the needle is moving upwardly or away from the needle-thread cutter and when all danger of interference between the needle and thread-cutter is past. The line ,/z, F ig. 8, represents the position of the main-shaft when the take-up 9 is at its highest point and when the plunger 56 engages the stop-notch 59. The line b, Fig. 9 represents the position of the mainshaft at the end of its overthrow motion and the line c represents the position of the mainshaft at the end of its recovery motion; lines c and a. being in the same vertical position.

By virtue of the slots in the plate 69 lirough which the screws pass, said plate may be adjusted circular-ly relative to the gear 47 to insure that one ot the shoulders 74 will be carried past the hook-shoulder 68 at the end of the overthrow motion of such gear.

The tension-release arm 32 is timed to release thetension before the thread-cutter is trilbed,so that free needle-thread will ybe supplied to be carried into the nipper assoliated with the thread-cutter.

lil)

The work-clamp lock-lever 43 will also be moved te unlocking or dotted line position, Fig. 2, by the recovery motion of the mainshatt 7 and gear Ll?, so that the usual manually operated work-clamp-litting and under threznl-cutter-operating lever 35 cannot be actuated while there is danger' oi interference with the moving needle.

Means are preferably provided to insure the closing of the work-clamp prior to startingl the machine. To this en-d there is cennected to a lateral-arm 57 on the stop-motion lever 57'one end of a` link 79 the other end of which is Connected to a lever 8O fulcrumed at 8l on the machine-bed and having an angular arm 82 extending back of the leverarm 84, F10'. 2, which is rigid with the manually operated clamp-lifting arm 35. Vhen the stop-motion lever 57 is tilted to running or full line position, Fig. l, the link 79 pulls on the lever 80 'forcing its arm 82 against the side et the lever-arm ed and forcing the lever upwardly to lower the work-clamp.

The cam-incline 78 between the neck 78 and head 7 6 of the pin 77 serves to retract the lever 67 from the cam-plate 69 when the stop-motion lever 57 is shifted to running position. This motion releases the rock-shaft 28 which thereupon moves to restore the tension on the thread and allow the clamp-locking lever 43 to enter the notch 42 in the vertical rod 39.

lhile the invention is shown as embodied in a machine having the stop-motion mechanism of the Allen and Myers application, referred to, I do not find it necessary to coniine the invention to that exact mechanism. The invention is obviously adaptable to any torni of stop-motion mechanism, the oper tion of which involves a retrograde motion of certain parts immediately preceding the inal stoppage of the machine.

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

l. A sewing machine having stitch-forming n'iechanism, a main-shaft, a stop-motion device including means for imparting aA retrograde motion to the main-shaft betere bringing it to a iinal rest, a thread-cutter, and means actuated by fan-element of the machine in the retrograde motion et the parts or operating said thread-cutter.

2. A sewing machine having stitch-forming mechanism, a main-shaft, a stop-motion device including a resilient buffer for absorbing tle momentum of the machine in bringing it to rest, a needle-thread cutter, and means actuated by an element of the machine in the recovery motion oli' the parts succeeding the butler-compressing motion for operating said thread-cutter.

3. A sewing machine having stitch-forming mechanism including a reciprocating needle, a main-shaft, a needle-thread tension device, a needle-thread cutter and nipper, a

stop-motion device including a resilient bufiter for absorbing the momentum of the machine parts and imparting a reverse motion to said parts before bringing the machine to a inal position of rest, and means actuated by an element of the machine in the reverse motion of the parts for lirst releasing the tension-device and then operating the needlethread cutter and nipper.

4. A sewing machine having in combination, stitch-forming mechanism including a reciprocating needle, a work-clamp, a needlethread take-up timed to be at its highest point after the needle has executed the first part of its down-stroke, a needle-thread. cutter mounted on said work-clamp to cross the path of the needle, a main-shaft, a stop-motion device inclnding means for imparting a retrograde motion to the main-shaft before bringing it to a linal rest with the take-up at its highest point, and means actuated by an element et the machine in the retrograde motion of the parts for operating said thread-cutter.

5. A sewing machine having, in combination, stitch-forming mechanism, a main-shaft, a stop-motion device including a stop-cam and gear connected to the main-shaft to run at a reduced speed and a resilient buffer between said stop-cam and gear to absorb the niornentum of the machine parts and impart a reverse motion thereto before bringing the machine to a iinal position of rest, a. needlethread cutter erossing the path of the needle, and means actuated by said buffer-spring in the reverse motion of the parts for operating said thread-cutter.

(3. A sewing machine having a frame including a bed, an upright standard and overhanging bracket-arm, stitch-forming mechanism, a work-clamp, a. main-shaft disposed within said bracket-arm and connected to operate said stitch-forming mechanism and work-clamp, a stop-motion device applied to the rearward end of the main-shaft and including tight and loose pulleys, a belt-shipper, a stop-cam, a stop-plunger and butler means between the stop-cam and the mainsha'i't operating to absorb the momentum of the machine and impart a reverse motion to the parts in bringing the machine to a final position et rest, a rock-shaft mounted externally ot and alongside said standard, means auxiliary to the sewing operation connected to be operated by said rock-shaft, and means controlled by the operation et said stop-motion device for actuating said rockshait by the reverse motion of the parts following the butter-compressing motion.

7. ln a sewing machine, stitch-forming mechanism., a stop-motion device :for controlling its period of operation, said stop-motion device having` a stop-cam, a tilting stop-niotion lever having ruiming and stopping positions, a stop-plunger carried by said lever for cooperation with said stop-cam, a buil'erspring for absorbing the momentum of the machine and imparting a retrograde motion to the parts in bringing the machine to a final position of rest, a shouldered element running with the main-shaft, a roclesliaft, an element connected to said rock-shaft and adapted to be operated by said shouldered element in the retrograde motion of the mainshaft following the buffer-compressing motion, means on the tilting stop-motion lever for holding said last mentioned element out of range of said shouldered element while the stop-motion lever occupies running position, and means auxiliary to the sewing operation connected to be operated by said rock-shaft after the sewing operation is completed.

8. An automatic sewing machine having, in combination, stitch-forming mechanism, a work-clamp, a stop-motion device for bringing the stitch-forming mechanism to rest at a predetermined position in a stitch-forming cycle, said stop-motion device including coacting stop-elements and buffer-means for absorbing the momentum of the machine parts, said buffer means operating to impart a reverse motion to the machine parts following its momentum absorbing action, a fol1ower-element adapted to be actuated by one of said machine parts during the reverse motion, means connected to the stop-motion device for holding said follower-element out of engagement with its actuator during the sewing operation, and means operated by said follower-element for performing a desired operation subsequent to the sewing operation.

9. A sewing machine having stitch-forming mechanism, a main-shaft, a stop-motion device having a tilting stop-motion lever, a stop-cam running with said main-shaft, a stop-plunger carried by said stop-motion lever, a buffer-spring interposed between said stop-cam and main-shaft, whereby the mainshaft has a buffer-compressing motion followed by a reverse motion, a rock-shaft and connections for performing a desired operation subsequent to the sewing operation, a rock-shaft actuator running with the mainshaft, a follower connected to said rockshaft and adapted to engage said actuator, and means mounted on said stop-motion lever and formed with a cam-portion for controlling the motion of said follower into and out of engagement with said actuator, said actuator comprising an element having a shoulder arranged to move said follower only durn ing the reverse motion of the main-shaft following the bu'er-compressing motion.

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

EDWARD B. ALLEN.

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