US1447941A - Sewing machine - Google Patents

Description

Mar. :6, 1923. 1,447,941

A. F. FlFlELD SEWING MACHINE Filed May 1, 1919 5 sheets-sheet 1 INVENTOR BW A TORNEY Mar. 6, 1923. v 1,447,941

A. F. FIFIELD SEWING MACHINE Filed May l, 1919 5 sheets-sheet 8 v mil P15 I INVENTOR A TORNEY "Mar; 6, 1923. 1,447,941

' A. F. FIFIELD SEWING MACHINE,

Filed May 1, 19-19 v 5 sheets-sheet 5 INVENTOR BY A TORNEY Mar. 6, 1923. 1,447,941

A. F. FIFIELD SEWING MACHINE Filed May 1, 1919 5 sheens-sheet 4 INVENTOR Mar. 6, 1923. 1,447,941 A. F. FIFIELD SEWING MACHINE Filed May 1, 1919 5 sheets-sheet 5 I INVENTOR mag w A TORNEY Patented Mar. 6, 1923.

l i r i" ALBERT F. FIFIELD, OF NEWARK, JERSEY, ASSIGNOR TO THE SINGER MANU- FACTURING COMPANY, A CORPORATION OF NEW JERSEY.-

1 SEWING moraine. 2

Application filed May 1,

. cation, reference being had therein to the accompanying drawings.

This invention relates to an improvement in machines for sewing on buttons, but it is equally. well adapted for barring, tacking and similar operations.

Machines of this type have previously been operated at the relatively lowspeed of 1,000 or 1,200 stitches per minute.

Various difficulties have also been encountered in cutting the threads at the close of a stitching operation, and previous cutters have been more or less unsatisfactory and complicated. WVhen the last needle-loopis detained for cutting at the close of the operation, it is desirable that the work limb or limb of the loop leading to the last stitch be cut and that the out be made as close to the work as possible, as a neat finish. is thereby imparted to the work, thread waste is obviated, and the limb of the loop leading to the needle is left long enough to be readily gripped and held during the start of the next stitching operation In prior machines, however, the needle-loop .is in such a position that when the last one is held for cutting, its limb leading to the needle is adjacent the bobbin thread, and the limb leading to the work, which it is desired to cut, is relatively remote from the bobbin-thread. Hence ithas been. necessary to either provide additional devices, for properly deflecting or. positioning the work limb of the needle-loop that it may be cut by the same severing means as used for the bobbin-thread, as shown for example in patent to Mills. No. 1,016,226, January30, 1912, or else the needle and bobbin-threads are cut by different severing means, as shown in patent to, Thomson, No.,702,832, June 17, 1,902. In the latter event, in some cases independently operated cutters are used, in others two independent cutters operating in unison, and in still others a single device having separate cutting edges for the threads is used. All of these enpedients are objectionable as. adding .to the oomph sedan and for otherreasons.

Serial No. 294,034.

Among the objects ofthe present invention are to provide a machine of the type stated capable of operating at high speed, and to provide a thread cutter therefor of the greatest simplicity and efficiency while at the same time having all the features above enumerated as desirable. Other objects are to provide an'improved automatic ear OFFICE- I brake for the stop-motion which will lessen the shock of stopping at the high speed employed and quickly reduce the speed so that the thread-cutter mechanism, which is actuated by the. stop-motion, will not actuponthe thread with too greatv abruptness, to

provide means for regulating theaction of the brake tosuit different speeds,'.and to provide a combined manual'and automatic tension release for the needle-thread.

In the accompanying drawings, Fig. 1 is a front side view of a machine embodying my invention. Fig.12 is a 'rear side view of the same. Fig. 3 is an end view from the right in Fig. 1. Fig. 4 is an end view from the left in Fig.1, but with the face plate removed. Fig. 5'is a bottom .plan

view. Fig. 6 is a detail horizontal section above the worlr-plate-at the right-hand end of Fig. 1. Fig. '7 is a'bottom plan view of the throat-plate detached, showing the cutter i i mechanism. Fig. '8 is .a section on the: line 8-8, ofFig. 7, showing diagrammatically the positions for the needle and bobbin threads at the instant the cutter acts. Fig 9 is a perspective of the movable cutterblade. Fig. 10 is a perspective of the ledger v blade. Fig. 11 is a detail ofthe 'tension re lease mechanism. Figs. 6 to 11 are on an enlarged scale. Fig. 12 is'a diagrammatic view illustrating the relative positions of thetwo limbs of a needle-loop before the loop has been cast around the bobbin-thread,

and Fig. 18 diagrammatically representsthe relative positions of the twolimbs after-the loop has been cast around the bobbin-thread.

Referring to the 'dra-wings, the numeral 1 designates the base or' work plate of the: ma-

chine from' which rises. tlie stan'dard 2 carrying the overhanging arm and head- 4e 3 and at its rear outer end carries a loose pulley 6 and a fastpulley 7. At; its: other end (Fig. the shaft has a; crank 8-with crank-pin 9"on which is pivoted a take-up 10, and' a is pivotally connected to the takeupat main-shaft 5 is mounted within. the arm link 11 pivoted. to the. frame, at 12 This take-up construction is similar to that shown in patent to Diehl, No. 462,398, of November 3, 1891. A link 13 is pivotally mounted at one end on an offset extension 14 of the crank-pin 9 and at its other end is pivotally secured to a collar 15 on the needlebar 16, which latter carries at its lower end a needle 17. lVit-hin the standard 2 the shaft has abevel gear connection with a vertical shaft 18, and the latter in turn has a bevel gear connection with the rotary looptaker shaft 19. The shaft carries at its other end the loop-taker in. the form of a rotary hook with bobbin 21. (Figs. 4 and 5). In the present instance the gearing is such that the loop-taker makes two revolutions to each needle reciprocation. The hook is of well knownv form and operates in the ordinary manner to give a halt twist to the needle-loop as it is cast around the bobbinthread. The main-shaft. 5 also carries a worm 22 meshing with a worm-wheel 23 on a transverse shaft 24, on which shaft is mounted a controller cam-wheel 25 (Figs. 1 and 2 A jogging work-clamp or well. known form is provided, the same comprising a flat work-support 26 and a button-clamp 27. The button-clamp is supported by a pivotally mounted arched arm 28 and the latter is spring-pressed dmvnwardly by the flat spring 29. The work-su )port 26 and arched arm 28 are both carried by and moved with the clamp-lever 30. and movements transversely toand longitudinall oi? the work-plate are transmitted to the clamplever by the controller cam-wheel as to]- lows-6n its outer face the cam-whe l has a cam-groove 31, and a lever pivoted on the bracket 33 at .33 has a cam-follower 34 disposed in said groove. The lower end of the lever extends below the work-plate and has a ball connection with an adjustabe link adjustably connected with the slotted arm 36 of a 'pivotally mounted bellcrank-lever (Fig. 5). The other arm 37 ot the bellcrank-lever is connected by a link 38 with the clamp-lever and imparts movements thereto transversely of the work platev @n the other side of the cam-wheel is a cam-groove 39 (Fig. oted o the bracket has a eanrtollower 41' at upper end located in the groove The lower end of the lever 4. is grooved to embrace the upright rod 42 carried by the clamp-lever 30. Adjustably secured to the rod 42 is afcoiitaet block 43 through which. the oscillatory movements of the lower end of lever are transmitted to the clamplever to reciprocate the latter longitudinally of the work-platej The means above described for actuating the work-clamp are substantially those shown in patents to Sullivan, No. 777,564, of December 13, 1904 and Barron No. 1.093 241, of April 14, 1914.

A stop-lever 44 is pivotally mounted in lever 40 pivthe lug 45 on the frame for movement on an axis transverse ot the work-plate, and carries a belt-shifter 46 secured near its upper end. A spring-pressed plunger 47 at the upper end of the lever is adapted when in proper position to engage a stopping cam 48 on the main-shaft 13 to stop the machine. The stop-lever also has a limited sidewise or overthrow movement after engaging" the stopping cam. The stop lever is held out of engagement with the stopping cam and in the position shown in Fig. 2 by means of a spring-pressed latch 49 which engages the rear side of the lever. At the close of a sewing operation this latch is released by a cam-lug 50 (Figs. 1 and on the inner side of the controller cam-wheel 25. The stopmotion mechanism so far described is old and well known and is fully shown and described in patent to Barron, No. 1,093,241. A. coil spring 51 is secured at one end to the lower end o1 the stop-lever 44 and at its other end to a pin 52 projecting below the base, This spring tends to move the stoplever into stopping position. In starting the stop-lever is moved out of alinement with the stopping cam and into engagement with the latch 49 by means of a plunger-rod 53 (Figs. 2 and 5) located below the base and adapted to contact at one end with the lower end ot the stop-lever. This plungen rod is connected at its other end to the downwardly projecting arm 54 of a bellcrank-lever pivoted to lug on the lower side of the base. The other arm 55 of the bellcrzmk-lever may be connected to a treadle or other means for operating it. A coilspring 56 surrounds the plunger-rod and is confined between a collar 57 and a bearing lug 58 which spring tends to normally hold the plunger-rod out of engagement with the stop-lever.

(living to the high speed employed it has been found desirable to use a brake to assist the stop-motion mechanism in stopping; the machine. This brake con' prises a brakeshoe 59 adapted to bear against the fast pul le -J T and pivotally connected to the upper end of brake-lever (l0 pivote or the tran c at 51. A coil-sprinr' 3 end to the lower one at its oth 1- end to n a short vertical sl e and above the base. Above th lever is conne ted to the i spring 62 tends to throw the brake into action. and by means of the linger-lever (35 and arm the tension of the spring: may: be varied, to thereby vary the action of the brake at diiterent speeds. The brake acts only between the time the stop-lever is first tripped to shiit the belt and the time the overthrow motion of the stop-lever takes place. and the following means are provided to secure the result: small contact-lever in. r

engaged by 66 (Figs 5 and 6') is pivoted. at'fthe rear of the base, i to be actuated by the lower end oi'ithejstop,- lever 44in its sidewise" overthrowfmovemene and the opposite end ofthe contact-lever has a, pivotal connection with a sliding bar 67 having a cam lug 68 engaging a cam-lug 69 on the lower portion of the brake-lever. The bar 67', also has alatching projection70 enga'geable by one end of a latch-lever 71 pivoted at 72 and pressed toward th'egprojection by a coil-spring 73.v The other-end of the latch-lever 71" has a trip 7 eepivotally connected thereto "and yieldingly held in a position at substantially a right angle to the lever by means of a coil-spring 75. A stop (not shown) on the lower side of the latch lever 71 prevents the coil-spring 75 from pulling the trip 7 4: too far over.

"The thread-cutting mechanism comprises a downwardly extending bracket/7,6 (Fig. 7) secured to the lower side of the throat-plate and having pivotally mounted thereon a supportingarm 77 v for the thread-cutter. A needle-loop detaining and bobbimthread pull-off blade 78 is secured to the arm 77 by a. screw 7 9, which screw also secures in bobbin-thread nipper-blade 80 place a'flat v pressing against the part 7 8. Also secured to the arm 77 is a barbedplate 80 which actsto nip th'eneedle-tln'ead at the beginning of a sewing operation in 'a well kno-wn manner. The detz'tiner has an upwardly extending projection 81 forming a thread-cutting blade with 'an inclined beveled cutting edge 82 (Fig. 9).

beveled edge 83 ona ledger-blade 84 carried by a plate 85 secured to the throat-plateby a screw Xdjustment of the ledger-blade is provided for by slightly elongatingthe screw-hole in plate 85 as shown at 86 in Fig. 8. A spring-plate 87 is frictionally engaged by the point of the needle-loop detainer after passing the needle-hole 88 in thethro-at' plate in order to prevent the detained needleloop from slipping off. The throat-plate is provided with a recess 8-9-into which-the movable and ledger cutting blades p-roject (Figs. 7 and 8). A lever 90 pivoted to the base 91 is connected by a curved link. '92 to 4,] 1e arm 7 T At an intermediate point the lever 90 is to a lug 94; projecting from along slidebar 95 extendingtothe rear of the machine.

At its rear end the hart-)5 carries abl'ock 96 havinga notch 97 entered by the reduced lower end of a lever 98 pivotally mounted at. 99 on a bracket 100 secured to the-frame (Figs. 2;, 8' and 5.); The upper end o'lleve'r 95% carries a cam-follower movable in a cam-- groove 101 in the controller canrwheel 25. The block 96also carries a roller-stud 1.02

the forked arm'lOB of abellcrank-lever fulcruined at 104C,tl 1e other{ arm 105 of the lever-carrying-a plunger-pin 106 one" end of which lever is adapted This cutting edge co'acts with connected by a link 93 atitsend, which pinvis pressed outwardly by a sp-ri ng-1'07a The pin 106 isadapted to enter :a recess-108 in i the lower part of the st0p-lever--*4L45 just before the overthrow movement of the latter-"takes place. The above, described means for actuating the "slide-bar- 9 5 and bellcrank-lever 103, 105, team the "stop -lever and 'controller camwheel' "are substantially "those shown in patent'to Barron No. 1 0983241, above mentionedi*",

" A presserbar -1O9 is'mounted in the ma- I chine'ihead and spring-pressed downwardly by a spring";110'. =A bracket 111 secured to thepressenbar-has an extension '112zwith an opening. 113'- at its upper end into which projects the reduced end of a presser-liftingflever 11d pivoted to the overi'angingarm at 115.1 The lower end of the presser-bar hasa bracket 116 securedthereto which"brack et extends beneath an angled "arm '27" proj acting above th button clamp, whereby theclamp may be lifted by-the Presser-bar; .A rearwardly projecting arm 117: is j secured toflthe pr'esser-bar by asplit collar 1*1-8 (Figs. 45; and 11*); the rear end of thearmhaving aninclined'cam surface 117 engaging a cam one arm of 'a U- hapedlever 120 pivoted in the head at 121. Thfe'other arm ot' the lever enga si on-122; as shown in Fig.4! Twoangularly disposed arms 123'a11d124t, respectively, are

' 'es the tension release-pin of the tens'ecureCltO the free endo't the presser-li'ft ing lev'er 114:; The arm "123 has an eye 125 in its treeend, whereby treadleo'perat'ed :or other releasing means may be connected to 'nianually lift the button-clamp and release the needle-thread tension. The arm 1241: extendsdownwardly adjacent the periphery ffthecOnt-roller cam-wheehand has 'a pro- 128 has a-contactmember 129 on onearm -1;ma1apted-, to -engage the periphery of the controllercam-wheel inf'the path (if-the recesses 127,1and a spring: 1.31 urges said arm against the"periphery of the canbwheel. The other ai'rn- 132 of the angledever has connectedthereto a rod. extending for? wardly i'ntothe-head and-having anlarm 134- extendingtherefrom .a in the head; The arm 1 34;pressesiagainsttherear-end of the lever 1'35]PlVOtQCh130"itllQQIlGQCllB-bfll at 136, the lowed end iofi the. lever being in-v contactwith aispringlvzneedlez thread cl'arnpagt3 7. secured to An angle-le-ver; pivotedon the overhanging arm 'at V stoplever and allows the trip 74 to slip be hind it, and allows the latch 49 to engage lever 44. The brake is in inoperative-post tion and its operating parts are disposed as shown in Fig. 6, that is, the slide-bar67 is latched in its extreme right hand position, its cam-lug 68 has moved out the cam-lug 69 on the brake-lever 60 against the actionof the spring 62, thereby freeing the brake, and the trip 74 is in position to communi cate the initial stopping movement of the stop-lever 44 to the latch-lever 7 1 and free the latter from the projection on the slidebar 67. As the machine starts the contact member 129 has just entered a depression or recess 127 on the controller cam-wheel, thereby allowing the thread-clamp 137 to nip the thread as the needle goes down on its first reciprocation. The tension is open, due to the projection 124 on arm124 being on a projection 126 on .the controller camwheel. The bobbin-thread is held nipped by the nipper 80, and the cam-follower on lever 98 is about to move off the raised portion 141 of the cam-wheel 25. The needle rises and the hook pulls the loose thread end below the throat-plate. As the follower on lever 98 passes from the portion 141 to thedwell 139 the cutting mechanism is moved partially back and the barbed blade pulls the needle-thread end to one side and nips it close to the end against the throat-plate. The projection 124 also rides off the projection 126 on the cam-wheel, allowing the tension to close, and the contact piece 129 rides out of recess 127 on thecam-wheel, allowing the thread-clamp 137 to open. The stitching then proceeds in the manner usual with machines of this type. As the needle rises from its fourth reciprocation, however, the cam-follower .on lever 98 leaves. dwell 139 and passes into dwell 101, thereby completely withdrawing the cutter mechanism and releasing the needle-thread end when the barb 80 passes over recess 140 in the throat-plate, as at this time the needlethread is sufficiently sewed in to hold.

At the finish of a sewing operatiomthe needle makes several stitches in the same hole to act as tying stitches; As the needle goes down on its last reciprocation the cam projection 50 engages the latch 49 and releases the stop-lever 44, which latter is at once acted upon by its springand shiftsthe belt to the loose pulley and throws the plunger 47 into the path of the stopping cam 48. The lower end of thestop-lever, pressing on the trip 74, releases thelatch 71. The brake-lever spring 62 immediately throwsthe brake into action and as the lower end offhe brake-lever moves inwardly the cam-lug 69 acts upon the cam-lug 68, forcing the slide-bar 67 to the left and the lever 66 to the right and in contact with the stoplever. The mainshaft continues to turn, due to its momentum, the needle rises, and its loop is cast off and drawn up by the take-up the thread-cutter advances and the loop-detainer 78 pulls off the bobbin-thread and enters the loop. Tn Fig. 12 the relative positions of the work limb a and needle limb b of the needle-loop before the loop is cast around the bobbin-thread are diagrammatically shown, while lli g. 13 shows the manner in which the rotary hook has caused the positions of the limbs to be reversed, whereby the work limb a is so disposed as to be cut by the blade formerly used to cut the bobbin-thread only. The advance of the threadcutter is caused by the passing of the follower on lever 98 up the incline to the projection 141 of the cam-wheel, which moves the slide-bar 95 connected to the cutter mechanism. The bellcrank-lever 103, 105, being also connected to the slide-bar 95, is likewise moved, and its plunger-pin 106 springs into the recess 108 of the stop-lever 44 as it comes into, alinement therewith. As the take-up rises to tighten the loop on the detainer, the projection 124 rides up on the projection 126 of the cam-wheel, thereby releasing the tension as the take-up reaches top position. .The contact piece 129 also enters recess 127 on the periphery of the cam-wheel. causing the thread-clamp 137 to close, and finally the plunger 47 on the stoplever 44 comes into engagement with a. projection (not shown) on the stopping cam 48, causing a sidewise or overthrow movement of the stop-lever. This overthrow movement is transn'iitted by the bellcrank-lever 103, 105, and slide-bar 95 to the thread-cutter togive it its final thread-cutting movement. As the follower of lever 98 is opposite theenlarged recess 138 of theicam-wheel atthis time the lever 98 is free to move with the slide-bar as the cutting action takes place. As before stated, the means by which the overthrow movement is imparted is sub stantially that shown in patent to Barron No. 1,093,241 and forms no part of my invention. By reference to Fig. .8 it will be seen that the rotary hook has given the needle-loop a half twist, thereby disposing the work-limb a, of the'needledoop above the ,detainer 78 and in juxtaposition to the bob bin-thread c, and as the cutting edge 82 of the movable blade 81 meets the cutting edge 83 of the ledger-blade 84 the threads are simultaneouslysevered. The threads are out very close to the work, less than one-quarter of an inch in actual practice, the needlelimb bof the loop and the bobbin-thread c are both left'of su ficient length to readily form the first stitch of the next operation,

crating to give the needle-loop and the bobbin-thread is nipped by the spring-nipper 80. Asthe overthrowmo'vement takes place the lower end of the stoplever also actuates the lever '66, which'latter moves the slide-bar 6'? to the right,and the cam-lug 68 on" said'bar acts on the cam-lug (59 to force the lower end of the brake-lever 60 outwardly and release the brake. At the same time the latching projection 70 on the bar 67 comes into position to be engaged by the latch-lever 71 and thespring73 urges the latch into engagement with theprojection. As the stop-lever 4. 1- has moved'to'the left in its overthrow.movement the trip 17% can move outwardly along the right side of lever 4:4: as the right-hand end of latch-lever 71 swings outwardly. As the stop-lever 44 swings back from' its overthrow movement it moves trip 7 l slightly to. the right. against the tension of spring 7 5, and when thestoplever 'is reset at the beginning. of th next in rear of the lever again, shown in Fig.6.

It will be seen from the above'disclosure that applicant has provided a simple and efficient thread-cutting mechanism which with a'single cutter outs both threads simultaneously and close to the work, and which requires no special deflecting or positioning means for theneedle-thread loop to" enable the desired limb-thereot to becut. The automatic tension release p'rovldes; for the release ot the need-le threadat the proper time at the finish of a sewing operation and for gripping it again at the proper time in. beginning a new sewing operation, while at the same time allowing the tension to be manually released whenever the button-clamp is lifted. v the relatively high speed of l800"stit'ches per minute, and by use of applicants improved brake the machine is stopped without undue wear and tear on the stopmotio'n mechanism.

l Having thus set-. forth the nature of the lnvention, what I claim hereln 1's- 1. In a sewing machine, in combination,

stitch-forming mechanism including a reciprocating needle, a bobbin, a loop-taker operating to give the needle-loop a. half twist in casting it about. the bobbin and juxtapose the bobbin-thread and the work-limb of the needle-loop, an automatic stop mechanism, and means connected to said stop mechanism for severing the juxtaposed threads.

2. In a. sewing machine, in combination,

stitch-forming mechanism including a reciprocating needle, abobbin, a loop-taker opa half twist in casting it about the bobbin and juxtapose the bobbin-thread and the work-limb of the needle-loop, a take-up, an automatic stop mechanism, means for detaining the last nee- The present machine is" capable/of with a reciprocating needle, a bobbin, and

-loop taker 'oper'atingfin. a plane parallel to the needlelto givefthe needle-loop a half twist in casting it ab outc'the bobbin, and juntapose the bobbin-thread and the work-limb fol? theineedle-loop, of aneedle-loop detainiIig implement, and means on said imple-' ment-jt'or severing-the juxtaposed threads. 4:. in a sewing machine the combination with stit'ch form ng mechanism ncluding a needle, a zluijda loop-taker operating to give'the-needle loop a half twist and juxtapose the work-limbof the needle-"loop and "the bobbim'thread, of "a" loop-detaining im- "plement movable into the needle-loop and hav ng a cutting edgefor severing the ux- ,taposed threads "close to the work, thereby leaving the supply lin'ibfof the needle-thread long, enough to startthe next sewing operasewing operation its lower end' inovesoutwardly, allowing spring to pull trip [74:

tion.

to give the needle-loop a half twistfand taining impleinent moirable into the needle-loop and having a bobbinthread pulloff ,portion'and a cutting edge spaced from the portion for severing the juxta posed, thread; lengths; close to the work thereby leavingthesupply limbfof the needlethread longenough to start-thenext sewing operation, v

,6. Ina sewing machine, the combination to givethe needle loop a half twist and juxtapose, the work-limb, of the needlerloop, and fthe bobbin-thread, of athread -cutter includin abladehavingalpoint adapted to enter th'e lastineedle-loop and a pull-01f edge leading 'fromsaid point and adapted to engage thejuxtaposed thread lengths, said blade also having-a cutting edge spaced :iirom 5., Ina sewing machine, the combination f'wlt'h stitoh-forn'nng mechanism including a needle, a bobbin, and a loop-taker op ratmg with stitch-forming. mechanism including a I needle,z a bobbin, and a looprtaker operating said pull-off edgeffor severing the juxtaposed thread lengths close to the work.

7. In a sewing machine, the combination with stitch-forming mechanism including a reciprocating needle operating to throw out a loop, a bobbin, and a circularly moving loop-taker operating to pass by one side of the needle in a plane substantially parallel to the path of the needle, seize said loop, and

give it a half twist in casting it around the,

reciprocating needle, a bobbin, and a looptaker operating in a plane substantially parallel to the needle to give the needle-loop a half twist in casting it about the bobbin and juxtapose the bobbin-thread and the worklimb of the needle-loop, of a pointed needleloop detaining and severing blade, means for moving said blade into the last needle-loop in a direction substantially parallel to the plane of action of the loop-taker, and means for severing the juxtaposed threads.

9. In a sewing machine, the combination with a throat-plate andstitch-forming mechanism including a reciprocating needle, a bobbin, a loop-taker operating to give the needle-loop a half twist in casting it about the bobbin and juxtapose the bobbin-thread and the work-limb of the needle-loop, and stopping means for the stitch-forming mechanism, of a pointed blade adapted to enter and detain the last needle-loop and to pull off bobbin-thread, means on said blade for severing the juxtaposed threads close to the needle-hole in the throat-plate, and means connected to said stopping means for operating said blade automatically as the machine is brought to rest.

10. In a sewing machine, the combination with stitch-forming mechanism including a reciprocating needle, a bobbin, and a looptaker operating to give the needle-loop a half twist in casting it about the bobbin, of a blade having a pointed extremity for entering and detaining the last needle-loop and positioning the work-limb of the needle-loop in juxtaposition to the bobbin-thread, means on said blade for severing the juxtaposed threads, and automatic means for operating said blade as the machine is brought to rest.

11. In a sewing machine, the combination with stitch-forming mechanism including a reciprocating needle, a bobbin, and a looptaker operating to give the needle-loop a half twist and juxtapose the bobbin-thread and the work-limb of the needle-loop, of a thread-cutter comprising a single pointed blade adapted to enter and detain the last needle-loop, means on said blade for severing the bobbin-thread and work-limb of the needle-loop close to the work, and means on said blade spaced from the severing means for pulling ofi bobbin-thread and holding the needle-loop spread sufliciently to afford a needle-thread end long enough to begin a new sewing operation.

12. In a sewing machine, the combination with stitch-forming mechanism including a reciprocating needle, a'take-up,'a bobbin, and a loop-taker operating to give the needleloop a half twist in casting it about the bobbin and juxtapose the bobbin-thread and the work-limb of the needle-loop, of a threadcutter comprising a loop-detaining blade, means timed to move said blade into the needle-loop prior to the completion of the final take-up action, and means on said blade for severing the juxtaposed threads.

13. In a sewing machine, the combination with a throat-plate having a needle-hole and stitch-forming mechanism including a reciprocating needle, a bobbin, and a loop.- taker operating to give the needle-loop a half twist in casting it about the bobbin and juxtapose the bobbin-thread and the work-limb of the needle-loop, of a needle-loop detaining blade having a cutting edge the path of movement of which passes the needle-hole, and means for causing said blade to sever the juxtaposed threads substantially at the point of closest approach of said cutting edge to the needle-hole.

14. In a sewing machine, upper and lower stitch-forming mechanism including a needle, a bobbin, and a revolving hook whereby the needle-loop is given a half twist, a combined bobbin-thread pull-off and needle-loop detainer having a single cutting edge on its upper side, a coacting ledger cutting edge, and means for actuating said pull-ofi' in two stages at the close of a stitching operation whereby the bobbin-thread is first pulled off and the last needle-loop detained and then the bobbin-thread and worlelimb of the needle-loop are simultaneously severed by the cutting edges.

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