US2440227A - Sewing machine safety device - Google Patents

Description

' April 20, 1948. A. R. WOOD SEWING MACHINE SAFETY DEVICE 5 Sheets-Sheet 1 Filed Aug. 21, 1945 April 20, 1948. A. R. WOOD 2,440,227 SEWING MACHINE SAFETY DEVICE Filed Aug. 21, 1945 5 Sheets-Sheet 2 A. R. WOOD SEWING MACHINE SAFETY DEVICE April 20, 1948.

Filed Aug. 21, 1945 5 Sheets-Sheet 3 Elma/who's cflZ/i'ed $220000; 0313' A. R. WOOD April 20, 1948.

SEWING MACHINE SAFETY DEVICE 5 Sheets-Sheet 4 Filed Aug. 21, 1945 II E W M Hunfl m i m 0 a E 3 Mf o4 aav mm QM mm m m RN W J a mm a J NW MS H. 2

April 20, 1948. WQOD 2,440,227

SEWING MACHINE SAFETY DEVICE Filed Aug. 21, 1945 5 Sheets-Sheet 5 Patented Apr. 20, 1948 2,440,227 SEWING MACHINE SAFETY DEVICE Alfred R. Wood, Bridgeport, Conn, assignor to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application August 21, 1945, Serial No. 611,721

12 Claims.

' 1 This invention relates more particularly to a cyclically operable sewing machine having a clamp for holding the Work and which machine performs a sequence of operations and then comes to rest with its parts in predetermined positions.

Machines of this type are usually placed on a table and are driven from any suitable source of power through a start and stop motion mechanism which starts the machine at the beginning of the cycle and arrests its action at the completion of the cycle. These machines each comprise stitch-forming mechanism and a workholding clamp movable relative to each other to cause a group of stitches to be formed. Thread cutters are provided for trimming the upper and lower threads and a work-clamp lifting means is associated with the machine for the purpose of raising the clamp for insertion and removal of the work. The start and stop motion mechanism and the clamp lifting means are usually controlled by the operators feet and, if the operator depresses the clamp-lifting treadle before the machine has come to rest, the thread cutters will move across the needle-path and break or prematurely depress the work-clamp opening treadle which raises the work-clamp just prior to the time the start and stop motion brings the machine to rest and this causes the thread cutters to move laterally against the needle which has not yet been raised clear of the work. Sometimes the operator will depress the starting treadle before the work-clamp is in proper position. When this occurs the work is spoiled and the machine damaged.

The principal object of the present invention is to overcome the above described difficulties and to provide an improved safety device for sewing machines of the cyclically operable type which will prevent damaging the machine and the work and which will positively prevent the operator from lifting the work-clamp until the stop motion mechanism has brought the machine to rest. This invention also contemplates an improved interlocking mechanism which will prevent the starting of the machine until the work-clamp to sewing machines and and thread cutters have been released and have assumed their normal positions.

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 embodiment 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 right side elevational view of a straight buttonhole sewing machine equipped with the present invention. V

Fig. 2 is a rear elevational view of the machine, showing in addition the two foot-operated treadles, one for raising and lowering the work-clamp and the other for starting the machine.

Fig. 3 is a top plan view, partly in section, of the machine-bed, illustrating the work-clamp and its actuating mechanism and the needle-thread trimmer and its operating connections.

Fig. 4 is a fragmentary right side elevational view of the machine, showing the operating positions of the interlock elements when the workclamp is in lowered or work-clamping position and the tilting stop-motion lever is in machinerunning position.

Fig. 5 is a view similar to Fig. 4, but with the Work-clamp raised and the tilting stop-motion lever in machine-stop position, illustrating the manner in which the interlock lever functions to prevent the stop-motion lever from being manually swung into machine-running position.

Fig. 6 is a fragmentary right side elevational view, illustrating the stop-motion lever just after it has swung into machine-stop position and the way in which this action of the stop-motion lever turns the interlock-latch-pawl outwardly in preparation for its subsequent connection with the spring-[biased stop-motion plunger.

Fig. '7 is a fragmentary view of certain of the parts in Fig. 6, showing how the interlock-latchpawl swings inwardly into a position overlying the stop-motion plunger cross-bar when the stopmotion plunger is depressed by the stop-cam, so that whenthe stop-motion plunger snaps into the stop-notch provided in the stop-cam, the interlock latch will be retracted from beneath the work-clamp lifting stud.

Referring to the drawings, the machine chosen for the purposes of the present disclosure is a socalled straight buttonhole machine and has a frame. including a bed Ill from which rises a belt adapted to nun upon a nest of pulleys .20

carried, on a countershaft 2| journaled on the bracket-arm l2 and connectedtothemain-shaft [4 by gearing 22 in a manner fully disclosed in my U. S. Patent No. 2,338,611, issued January 4, 1944.

The work to be buttonholed is adapted to be held in a work-clamp comprising the usual lower work-plate 2,3 and an upper clamp-foot 24. The upper clamp-foot '24 is carried 'by the two-resilient arms 25 which are secured at their inner ends on a yoke 25 pivoted at 21 to .a lug 28 upstanding from the usual longitudinal slide-plate 29. The upper clamp-foot 24'is yieldingly urged downwardly into contact with the lower workplate 23 by a coil-spring 3t. To'provide'for separating the upper clamp-foot24 from the lower work-plate 23 for the insertion and removal of work, the yoke 26 is formed with a rearwardly extending tail-lever 3| adapted to underlie a roller 32 clamped for limited vertical adjustment intermediate the ends of a manually actuated clamp-lifting lever 33 fulcrumed at one end on a stud 34 threaded into the supporting bracket 35. At its other end, the lever 33' is fitted with a horizontally disposed stud 36-to the free end of which is attached a suitable connection-element 31 having fastened to its lower end a chain 38 connected to a foot-operated 'treadle '39 (Fig. 2). Depression of the treadle 39 will cause the'lever 33 to swing on the stud 34, against the-action of a spring til, thus causing the roller 32 to :engage the tail-1ever'3l and swing. the 'yoke 26 about its fulcrum ZL'thereby raising the arms25 and the upper clamp-foot 2.4.

To e'iiect shifting of the-work'relative to the endwise reciprocatory and laterally vibratory needle it, the work-clamp is slowly moved in step-by-step fashion, first awayfrom'the standard H 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 workclamp derives its step-by-step movements from the usual feed-cam 41 (Fig. 1) .carried at :the lower end of a vertically disposed feed-shaft 42 journaled'in the bed and the bracket-arm of the machine. The connections between the workclamp and the feed-cam are'identical with those disclosed in my United States Patent No. 2,411,493, issued November 19, 1946, as are also the means employed for intermittently rotating thefeed-shaft 42 and the feed-cam 41.. Therefore, a description herein of those mechanisms of the present machine is not deemed necessary.

As is customary in group-stitch sewing machines of-the type disclosed, there is provided a needle-thread cutter and a bobbin-thread cutter. The needle-thread cutter, which is best illustrated in Fig. 3, and'which forms the subject of my U. s. Patent No. 2,426,543, dated August 26, 1947, comprises a compound thread-cutting and -nipping blade 43 mounted upon the lower endof a vertical shaft "44 journaled in the upper clamp-foot 2-4. Secured to the upperend of the shaft 44 is a crank-arm 45 connected with one end of a push-rod 46 disposed in the direction of longitudinal movement of the work-clamp and endwise slidably supported in an ear 4'! bent upwardly from the yoke 26. The ear 4! also serves in conjunction with a fixed collar 48 upon the push-rod 46 as a stop to limit the endwise motion of the rod under the'action of a spring 13 connected at one end with'the ear "41 and at the other end with a second collar 50 fixed on the push-rod 4B. The previously mentioned feedshaft 42 isemade use of to control the necessary endwise movements of the push-rod 46, first, to

effectthe release ofthe nipped beginning end of the ineedle thread, second, to set the compound cutter and nipper blade 43 preparatory to the :retrimming' of .the beginning thread-end and,

third, .to reset the blade 43 preparatory to the trimming of the finishing end of the needlethread and nipping the beginning end of the needle-thread for the-beginning of the nextz-sewing operation. The feed-sl'iaft 42 Fig.i3);has

adjustably fastened'thereon a cam '5! .which is adapted to rotate with the feed-shaft :into engagement with a follower-nose 152 formed con .a lever 53, which lever 53 is-connectedLbyaJink-M to a second lever -55 of which the free erld is adapted to swing intoengagementwithta block 56 clamped on the push-rod 46. The cam '5l, through the :linkage just described, actuatesthe push-rod 45 in a .manner such that the above mentioned first and "second operations are .per-

formed. The thirdoperation is effected "through a second cam 51whichdspreferably integralwith,

but spaced vertically above, the cam 5!. The second cam 51 actuates 'the linkage including a two-arm lever 58 and a bell-crank lever .59 of which one of its limbsis disposed to swing .into engagement withthe blocktfi on-the push-rod-AS. The secondcam -51 and its linkage are proportioned sothat thepu-sh-rod 46 isshiftedendwise against the .action'of the spring 49 sufficiently far to permit -a spring-influenced latch-lever 0 to drop into a stop-notch 6| formed .in thecollar '43. The latch-leverGfi thus maintains the.com-

pound cutter and nipper blade 43 -.in reset position preparatory to .the trimming of the .finishing end ofthe needle-thread and nipping the beginning end .of the needle-thread .for the'beginning of the .next sewing operation.

The latch-lever 60 is actuated to release the .push-rod 46 and .permit .the cutter and .riipper .blade 43. to perform its final .thread-cuttingand nipping operation .by a tripping element 52 se- .curedto alink-B3 adapted to'be actuated by the work-clamp raising. mechanism. It will be observedin Fig. 1 thatthe'link 63 is connected, as

at 5.4, to a verticallydisposed rock-'lever'65 pivoted at 65 to the bed I0. Formed adjacent the upper end of the rock lever 65 is a eam-slot '61 having an actuating. portion 68 and .a dwell-producing portion .69, which cam-slot is entered by the stud 36 to which is connectedthe work-clamp raising foot-treadle 39. The cam-slottl ispreferably formed with an actuating portionand a dwell-producing portion so that the link 6 3 is actuated only during the initialdepression of the work-clampraising foot-' treadle "and during the time that the stud'36 is'tracking'the actuating 'to release the work.

The 1ink'63, in addition to releasing the latch fill'toenable the needle-thread-eutter to perform its final thread-cutting and nipping operation,

also is connected to actuate the bobbin-thread cutter, whereby the two sewing threads are cut simultaneously. As will be seen in Fig. 3, the link 63 at its forward end is connected to the shorter limb of a bell-crank lever 10, the longer limb of which is operatively connected to a cross-slide H formed with a rack 12. The rack 12 meshes with teeth 13 segmentally formed in a portion of the periphery of a carrier 14 to which is detachably secured a bobbin-thread pull-01f finger 15 and a thread-cutting blade 1 6. The constructive features of the disclosed bobbin-thread pull-off and cutting mechanism are fully shown in my copending application Serial No. 611,725 filed August 21, 1945 and, therefore, no further description in this case of the details of this mechanism is deemed necessary. Sufiice it to say that the initial actuation of the work-clamp raising foottreadle 39, through the stud 36, swings the lever 65 forwardly, thus endwise moving the link 63 so that the tripping element 62 engages the latch 60, thereby releasing the needle-thread cutter for its final thread-cutting and nipping action, and simultaneously pivots the bell-crank lever which actuates the cross-slide 1| to oscillate the carrier 14 supporting the bobbin-thread pull-oil? finger and cutting blade, thereby to pull-off a measured length of bobbin-thread from the supply to be used in the next buttonhole and sever the bobbin-thread leading to the last stitch in the buttonhole.

To provide means for stopping the machine at a predetermined final position, there is provided a common form of start and stop motion mechanism, the constructive features of which are fully illustrated and described in my previously mentioned U. S. Patent No. 2,338,611. Referring to Figs. 1 and 2, it will be seen that the standard I I has fastened to it a bracket 11 having upwardly projecting spaced arms for the trunnion-screws 18 which support a tilting stop-motion lever 19. Mounted to slide vertically in the stop-motion lever 19 is the usual stop-plunger 80 which is pressed upwardly by a spring 8| for cooperation with a double notched stop-cam 82 mounted on the countershaft 2| and having eccentric stopplunger depressing portions 83 followed by stopand rebound-preventing notches 84. When the stop-motion lever 19 is in running position (see Fig. 4), the upper end of the plunger 80 is disposed forwardly of the stop-cam 82 and is out of range of the latter. When the stop-motion lever I9 assumes its stopping position (see Figs. 1 and 2) the plunger 80 is moved to a position under or within range of the cam 82, whereupon the eccentric portion 83 of such cam first depresses the stop-plunger 80 against the force of the spring 8| and then releases the plunger as the latter rides off the end of the eccentric portion 42 and is projected upwardly into the stop-notch 84. The stop-motion lever 19 is held in its running position by means of a spring-biased latch-lever 85 which enters a notch 86 in the 'side of a rod 81 controlled by a foot-treadle 88; the rod 81 being connected at its upper end to the free end of an actuating arm 89 rigid with the stop-motion lever 79. The latch-lever 85 is adapted to be acted upon by a suitable tripping element 90 carried by the feed-cam 4|; releasing of the latch-lever 85 permitting a coil-spring 9| surrounding the treadle-controlled rod 81 to swing the stop-motion lever 19 with its plunger 89 toward and into the range of the stop-cam 82.

Considering now the improved safety devices of the present machine which form the subject of this case, it will be understood from the above description, taken in connection with the accompanying drawings, that whenever the foottreadle 39 is manually depressed the clamp-lifting lever 33, through the rock-lever 65 and link 63, actuates the needle-thread trimmer and the bobbin-thread trimmer. It will be further understood that if the opening of the work-clamp is effected prematurely, the needle Iii may be in the work in which case the thread-cutting blades 43 and 16 will strike the needle as they swing to sever the sewing threads. To eliminate this condition, means is provided to prevent the opening of the work-clamp until the end of the stiching cycle. This means comprises a safety lever 92 of the first order, which lever is fulcrumed intermediate its ends on a bracket 93 secured on the bed I 0. The forward end 94 of the lever 92 is disposed to underlie the work-clamp lifting lever 33, while its other end is notched to provide a cam-wall 95 adapted to be engaged by a roller 96 freely journa-led on astop-motion lever extension 91. It will be seen in Fig. 1 that when the machine is not running, in which case the stop-motion lever 19 is in its normal vertical stopping position, the roller 96 is disposed so that the safety lever 92 assumes a position in which its forward end 94 is spaced from the work-clamp lifting lever 33. When the safety lever 92 is so spaced, the treadle 39 can be depressed to open the workclamp without any resistance from the lever 92. Fig. 5 illustrates the position of the parts when the work-clamp is opened. However, when the stop-motion lever '79 is tilted into its running position as shown in Fig. 4, the roller 96 engages the cam-wall 95 of the lever 92 and swings it about its fulcrum in a manner to bring its rearward end into a position underlying the roller 96 and to bring its forward end 94 up into substantial engagement with the bottom of the workclamp lifting lever 33. When the safety lever 92 is in the position shown in Fig. 4, the work-clamp cannotbe opened, inasmuch as the forward end 94 of the lever 92 functions as an abutment and precludes the lowering of the work-clamp lifting lever 33. The lever 92 is effective to prevent the premature opening of the work-clamp as long as the stop-motion lever 19 is in its running position, as shown in Fig. 4. Also, as clearly shown in Fig. 5, the lever 92 is effective to lock the stopmotion lever 19 in its stopping position "during the time that the work-clamp is opened.

As previously explained the stop-motion lever 19 is spring returned from its running position, shown in Fig. 4, to its stopping position, shown in Fig. 6, when the latch-lever 85 is released by the tripping element on the feed-cam 4!. Following the release of the stop-motion lever 19, the machine continues to operate for substantially half a revolution of the countershaft 2|, during which time the needle is on its last upstroke. During the half revolution of the countershaft 2|, the stop-plunger is depressed by the eccentric cam 83 and the stop-notch 84 is brought into register with the stop-plunger which thereupon is projected into said stop-notch to lock the machine. During this half revolution of the countershaft, the safety lever 92 is positioned as shown in Fig. 6, in which position the work-clamp can be opened. If, however, the Work-clamp is opened during this period, the thread-cutting blades 43 and 16' would strike the needle. In order to defer the opening of the work-clamp until the needle has been withdrawn a safe distance from thework, I have provided 1; asafetyJatch-member: 98:pivoted; as at .99itozthe verticallyedi'sposed' rock -lever 65;? The latch member 98:.is' f ormed with an :abutmenteledgsaI which, as shownrinuFi'g; 6, is adaptedito runderlie the studr 3l5l and'preventithe lowering ,of-thezworb clamp lifting lever? 33'Ewhen. the lever 02::issin" the position illustrated. In ordertoswin'githezlatcm member 08 from its 1 effectiveepositions. shown: in Fig; 6;.toits inefiective or. inoperativexposition, shown in Fig. 1, 11 have connectedttothesupper endsof the latch-memberra" link I 0%I whichzissattached to the depending :and'ioffset LIimhI-I 0210f .a bell-cranktlever l 03: pivotedvon a supportingsstud IML threadedi'iintothe: standard. I;I.. The. bellcranksilever, I ll3iis adapted:totbeturnediaboutlthe supporting istud' 1M bya pawl'.I.05upivotedxto the bell-crank: lever and: disposed tocooperate. with a cross-bar I06 adjustably clamped; to the stop"- plun-ger 80; Fig. 3,? by. theLSBt-i-SCIBW I003 The safety latch-:member 9.8'-1lS:= controlled .in the:following. manner. Beginningrwith the-parts in the position as-illustrated in Fig-i16;.infwhich position the latch-member; flaris effective' to. prevent the. opening; of thework-.cl-znnp, the stopmoti-onleverhas. just; been released and. has sprung into. its stopping. position, wherein: the stopeplungera 00: is abouti to be en'g'agedi byi'the eccentric. portion .03. of :the istop-camnfl: As the stop-. cam "82 icontinues to rotate, theestop-plunger is depressed; causingthe cross=barz I06. secured thereon ;to..be IOWeredIbeneath-the shoulder 108:01 the. pawl I05.'.. In response toaicoilespring I09; the pawl I snapsiinto 6a: position determi-neclzby a stop-screw -'l I 0', seei'Fig. 3.',a in;whic1'i- .posi-tionithe pawl I:05iis disposedito be .enga'ged'rbyrthe crossbar Ill-3': as the latter springs: upwardly-with the stopeplunger when the latter; projects .intotthe stop-enotchad of'thestop cam 82'... The v npwa'rd movement of the stop-plunger: 80'.rinto.:the'. stopnotch 84, through' the pan/110.5, .turnsathe latch; member '98; against" the action=o a. coilrsprin'g III; about its pivot 99 fromits-effictive position shown in Fig. .6f toiitss inefiectivenposition shown in Fig. .1: Inasmuch zaszthe latch-memberziiairee mainsinits efiective positionsuntil;the:-'stopplunger enters thestop-notcht I inithe stop-cam 32, .the- Work-clamp cannot. be: openedc after the stitching has been completed andruntil' themeedle on its lastupstroke has been withdrawnzfromtthe work;

When the machine is; stoppedwithftherparts in the positions shown in Fig. 1; .thastopeplunger 80- is in the stop-notch 80 and the pawl I 05; is bearing against the stop-scre-w l I 0 andzis engaged by the crossbar I05thus maintaining the bell-: crank lever I03,- in' opposition to =the coil-spring III, in a position such that thelatch-.member 9B is-in inefiective -or inoperative-position; When it is desired to start the machine, the stop-motion lever "I 9' is tilted into running. position; as .lShOWII in Fig; 4. The tilting of the stop-motionzlever Wcauses the: cross-bar IW totmoveito thezleft (Fig. 4 from beneath'the shoulder I'08.ot thepawl 505', thus disconnecting the bell-=cranki lever I03 f rem-the stop-plunger 80 and permittingrtheicoih spring I H to swing the bell-crank lever iniatclocka wise-directionto pivot the latch-member :98i'relative to the rock -lever andatherebyxpositiorr its abutment led-ge I00 beneath the. stud' 35.. Therine clinationof the abutment-ledge I00 is suchasdso permit easy=.m0vement oi the latch-memberoQBf-he: neath the stud-30 but approaches theslhorizontal sufiiciently close as to eliminaterthe'eff'ct .ofiany reactionary force which would 'tend'zto :swingith'e' latch-member out of effectiveposition'slionldzthe operator apply excessive: pressure. on. the foot treadle' 39; It .will betunderstood that inztheievent the operator, in: anticipating! thev ending: of: the stitching: c-ycle,-. prematurely appliespressurei on the. workclamp .lifting treadle 39; this' pressure will notprevent the-safety latch mem'b'eri98 from beingawithdrawu frornfbeneath the stud. This advantager is 'attaineclby virtue? of the :fact' that the cross-bar I 05, when the stop-plunger. 802: is fullyrdepr'essed; is spaced: below the. shoulder. I08 on:thetpawl.I05; as shown in'li'ig. 7, thus: enabling thetcrossebarr:I06 to hitlthe shoulderswith asharp blow'when thenstop-plunger is released .to project into thestop-notch 8'4. The blowthus applied'to thezpawl 'I Wis-adequately 'sufi'icient to. retract the latch-lever: 982 at leasti-beyondia pOintLVeIticalIy beneaththe center of thestudxflfi, after .whichthe pressure; on'ithettread'le :39; throughl thexcam'. action zofithe. curved bottom surface of the stud 36 on the. latchem'emb'er 198*,- will expedite the retractionoff the. latch-member into its ineffective position. In". other Words,.the..improved' safety means -.will operate efficiently whether or hot-the operator. prematurely applies'pressure on: the Work+ clamp; lifting :treadle'.

It :wi-llbeiunderstoodfrom the above descrip tionithat thesafety' latchemember 98 and its controlling'mechanism areidesigned so that'the safety' latoh-mrember is effective throughout the entire stitching. cycle up.-to.'and including-thatipart of the last upstroke of the needle in which-the needle is disposed in the work'. In fact, the safety-ilatch'-member90 not= shifted-into its ineffective position until the needle on its last upstroke is-wel'l above the topof' 'the work, thus making it: impossible for the th-read -cutting bladesto strike'the needle. While the safety lever 92 is-effecti-ve to prevent-the opening of' the Work-clamp whenthe stop-motion lever-I9 is in machine-running position, it is also 1 operative when" the" work-clamp 2 is opened to prevent the shifting-of the stop-motionlever 19 from its'stopping position to its-running position; The two safety'elements 92 and- 98 operate-insuch a way as to maintain the Work-clamp and thread-cutting mechanisms locked during" the sewing and are-hot unlocked until-the stop-plunger has been-projected fully'into'thestop-notch 84 and the'machine finall'y'brought to'rest a't'the completion of the last revolution of the main-shaft with the 'needle ou-tof'the work. The machine and its productare thus fully safeguardedagainst damage by a premature operation of the parts adjacent the sewingpoint;

Having thus set forth the-nature: of the invention, what I'ciaim' herein is."

1; In asewing'machine. adapted to performa sequence of; operations and come .to restin a predetermined position, in combination; driving mechanisnrfor said machine including a startandstopemotion mechanism, manually controlled means for initiating operation of .the machine, a workeclamp, means for.-raisingand'lowering,said Work-clamp, andmeans under control of. said start.- andistopi-motion.mechanism for. preventing saidwo1 k-clamp:from being-raised while the machinevis in, operation and .for preventing the initiation'of. the beginning of. the sequence of operationswhen the work-clamp is raised, said last=named means --inclucling.-a pivot-:lever of the first order with its ends cooperating with the startand stop-motion mechanism and the-clamp liftingirm'eans; and a :pivoted'latch under control of thestartand: stop-motion mechanism and 9 shiftable into and out of the path of movement of said clamp lifting means.

2. A sewing machine having, in combination, stitch-forming mechanism, a work-clamp, a startand stop-motion device including a tilting stop-motion lever, a manually operable lever for raising and lowering said work-clamp, a safetylever pivoted between its ends and having one end underlying said manually operable lever for direct engagement therewith and its other end formed with a cam-wall adapted for cooperation with said tilting stop-motion lever, whereby when the stop-motion lever is swung to start the machine the manually operable clamp lifting lever is locked against movement and when the manually operable clamp lifting lever is depressed the tilting stop-motion lever is locked against movement.

3. A group-stitch sewing machine having, in combination, stitch-forming mechanism including a needle, a work-clamp, a manually operable lever for raising and lowering said work-clamp, a startand stop-motion mechanism including a movable stop-motion lever for arresting the op eration of the machine at the completion of a predetermined group of stitches, first safetymeans controlled by said stop-motion lever and cooperating with said manually operable lever for preventing the opening of said work-clamp during the entire group-stitching cycle up to and including that portion of the last upstroke of the needle in which the needle is in the work, and an independent second safety means rendered operative when the work-clamp is open for looking said start-and-stop motion in machinearresting position.

4. A group-stitch sewing machine having, in combination, stitch-forming mechanism including a needle, a work-clamp, a manually operable lever for raising and lowering said work-clamp, a startand stop-motion mechanism including a movable stop-motion lever for arresting the operation of the machine at the completion of a predetermined group of stitches, safety-means controlled by said stop-motion lever and cooperating with said manually operable lever for preventing the opening of said work-clamp during the entire group-stitching cycle up to and including that portion of the last upstroke of the needle in which the needle is in the work, and an independent safety-means under control of said work-clamp lifting lever and engageable with said movable stop-motion lever for preventing the starting of the machine while the work-clamp is open.

5. A group-stitch sewing machine having, in combination, stitch-forming mechanism including a needle, a work-clamp, a manually operable lever for raising and lowering said work-clamp, a startand stop-motion mechanism including a movable stop-motion lever for arresting the operation of the machine at the completion of a predetermined group of stitches, a safety latch-member controlled by said stop-motion lever and cooperating with said manually operable lever for preventing the opening of said work-clamp when the stop motion lever is in running position, and an independent safety-means including a pivotally supported lever under control of said work-clamp lifting lever and engageable with said movable stop-motion lever for preventing the movement of said stopmotion lever to running position while the workclamp is open.

6. In a cyclically operable sewing machine, a

startand stop-motion mechanism, a work-clamp, a lever for raising and lowering said clamp, a stud carried by said lever, a, latch-member shiftable into and out of the path of movement of said stud, and means under control of said startand stop-motion mechanism for determining the position of said latch-member.

7. In a cyclically operable sewing machine, a startand stop-motion mechanism, a work-clamp, a lever'for raising and lowering said clamp and r ying a stud, a member formed with a camslot through which said stud extends, a shiitable latch-member for locking said stud at one end of said slot, and means connecting said startand stop-motion mechanism with said latch for controlling the position of said latch-member.

8; In a cyclically operable sewing machine having stitch-forming mechanism including a threadcarrying needle, a startand stop-motion mechanism, a work-clamp, a manually actuated lever for opening said work-clamp and having a stud, thread-severing mechanism, an actuating member connected with said thread-severing mechanism and formed with a cam-slot through which said stud extends, a shiftable safety latch-member for locking said stud at one end of said camslot, and means connecting said startand stopmotion mechanism with said latch-member for moving said latch-member into stud-locking position when said startand stop-motion mechanism is shifted into running position, thereby to prevent premature opening of the work-clamp and operation of the thread-severing mechanism.

9. A group-stitch sewing machine having, in combination, stitch-forming mechanism including a thread-carrying needle, a startand stopmotion mechanism including a notched stop-cam and a movable stop-motion lever having a stopplunger adapted to enter a notch in said cam to stop the machine, a work-clamp, a manually actuated lever for opening said work-clamp and carrying a stud, thread-severing mechanism, means for actuating said thread-severing mechanism including a member formed with a camslot tracked by said stud, a shiftable safety latchmember for locking said stud at one end of said cam-slot, a spring for biasing said latch-member into stud-locking position, and means for moving said latch-member out of stud-locking position at the completion of the stitching operation, said last named means-including a pawl adapted to be releasably connected with said stop-plunger and actuated thereby to move the latch-member out of stud-locking position during the time that the stop-plunger is entering the notch in said stop-cam.

10. A group-stitch sewing machine having, in combination, stitch-forming mechanism including a thread-carrying needle, a startand stopmotion mechanism including a notched stopcam and a movable stop-motion lever having a spring-pressed stop-plunger adapted to enter the notch in said stop-cam to stop the machine, a work-clamp, thread-cutting mechanism, a manually controlled mechanism for opening said work-clamp and actuating said thread-cutting mechanism including a shiftable element, a latch-member for locking said shiftable element against movement, a spring for biasing said latch-member into its element-locking position, and means for moving said latch-member out of its element-locking position, said means including a lever, a pawl for connecting said lever to said stop-plunger whereby said lever is actuated when the stop-plunger enters the notch anmeev in asaid .sstoptcam, and :means r for :disconnecting 'saidzfpawli fromsaid stop-plunger :When the AM- ter I is moved; into rmachine -running lposition.

11.1111 =-:a sewing :machine of :the :buttonhole type having :.a 'mainashaft, .xsewing .-"-and :workclamping :means :driven .iby 'said :maineshaft. work-clamp opening zmeans, and a start- .zan'd stopz-motion device including a :manually shiftable-;startin'gelementzapplied 'to the; machine :to -controlithe period "of operationz'of saidimainshaftr'the: provision of laLsingle lever-member of theifirst order :having oneof its sends disposed toibe iengaged -by one of i thev components of :the work-clamp opening means when said workclamp is opened andits other end notchedto engage sai d manually shiftable startingelement to :preventmovement of saidlstarting element to running position when said work-clamp is open.

1'2. :A-sewing. machine having; in combination, stitch+forming -mech-anism, a work-clamp, a startand stop-motion: device including a tilting stop-motionlever, a manually: operable leverfor raising and lowering -said work-clamp, and a 1-2 safety lever"pivoted-between its ends-and having one of its ends "underlying saidmanually operable lever and disposed-for direct'engagementatherewith and the other of-its ends disposed for direct engagement withsaid tiltin stop-motionlever, said safety-lever being constructed andarranged so that WhBIl'SELid tilting stop-motionlever isswung-to start'the machine thesafety lever is pivoted about its support into position to block movement of said clamp-lifting lever and when the manually operable clamp lifting lever is depressed the safety-lever is oppositely pivoted aboutlits support into engagementwith said tilting stop-motion lever thereby to lock it against movement.

ALFRED R. WOOD.

REFERENCES CITED UNITED STATES LPATENTS Name l 7 Date Althens Oct. "2, 1945 Number

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