US2436445A - Shoe sewing machine - Google Patents

Description

L. G. MILLER Feb. 24, 1948.

SHOE SEWING MACHINE Filed Feb. 2, 1944 5 Sheets-Sheet 1 Feb. 24, 1948. 1 s. MILLER SHOE SEWING MACHINE Filed Feb. 2, 1944 5 Sheets-Sheet 2 Feb. 24, 1948. G. MILLER 2,436,445

SHOE SEWING MACHINE Feb. 24, 1948- L. G. MILLER 2,436,445

SHOE SEWING MACHINE Filed Feb. 2, 1944 5 Sheets-Sheet 4 Feb. 24, 1948. L. e. MILLER SHOE SEWING MACHINE Filed Feb. 2, 1944 5 Sheets-Sheet 5 [nuenlor Lloyd G/IzZ/er B h After/26y mes-s Patented Feb. 24, 1948 SHOE SEWING MACHINE Lloyd G. Miller, Beverly, Mass.,

assignor to United Shoe Machinery Corporation, Flemington, N. J a corporation of New Jersey Application February 2, 1944, Serial No. 520,767

13 Claims. (01. 112-219) This invention relates to shoe sewing machines and is herein illustrated and described as embodied in a machine of the type disclosed in United States Letters Patent No. 1,864,510 granted June 21, 1932, on the application of Bernard T. Leveque. The machine disclosed in said Letters Patent has stitch forming devices that include a high speed reciprocating needle driven through a treadle-controlled mechanism. This mechanism is provided with an element which is movable to disconnect the needle from its actuating mechanism to insure stoppin of the needle at the upper end of its stroke regardless of the sewing speed of the machine or of the exact instant at which the treadle is operated with relation to the operating parts. It is desirable in such machines to provide for automatically stopping the needle drive mechanism upon breakage of the thread. However, any control mechanism responsive to the tension on the thread for disconnecting the stitch forming devices upon failure of such tension must have provision for accurate timing of the parts and positive disconnection at high speeds. Also, such a tension control will operate to prevent starting of the machine again unless further provision is made. Furthermore, a mere thread-tension-responsive member would not in itself be suflicient to insure the stopping of the needle in its uppermost position unless timed and connected in the proper manner.

It is an object of the present invention to provide an improved shoe sewing machine having a drive mechanism of the type which is provided with a movable element for disconnecting the actuated device, which is adapted to stop automatically upon breakage of the thread, and which, moreover, is free from the disadvantages above referred to. In accordance with this object, a feature of the machine illustrated herein consists in the provision, in a sewing machine having a Leveque type driving and stopping mechanism, of a means responsive to the loss of tension in the thread for causing the driving and stopping mechanism of the machine to stop the reciprocation of the sewing needle when the thread breaks or becomes slack for any reason. The illustrated machine is further provided with means for rendering the thread-tension-responsive member temporarily inoperative at the beginning of each sewing operation to enable the machine to run until the normal tension in the thread is developed. The illustrated machine is further provided with a means for again rendering the tension-responsive means operative after the normal tension is developed.

These and other features of the machine will appear more fully from the following detailed description when read in connection with the accompanying drawings and will be pointed out in the appended claims.

Referring now to the accompanying drawings:

Fig, 1 is a side elevation of a shoe sewing machine embodying the present invention;

Fig. 2 is an elevation as seen from the opposite side and on a larger scale showing the positions of the various members before the beginning of the sewing operation;

Fig. 3 is a view similar to Fig. 2 showing a portion of the needle driving mechanism during the normal operation of the machine;

Fig. 4 is a view similar to Fig. 3 showing the position of the various members just after the thread has broken but before the drive of the needle has actually been stopped;

Fig. 5 is a sectional view taken on the line V-V of Fig. 2;

Fig. 6 is a plan view in section of a portion of the mechanism shown in Fig. 5;

Fig. 7 is an exploded view of a part of the mechanism shown in Fig. 6; and

Fig. 8 is a sectional view taken on the line VIII-VIII of Fig. 2.

The supporting structure of the illustrated machine consists of a hollow frame or housing ill. The operating lnstrumentalities, as shown in Fig. l, consist of a needle ill (see also Fig. 2), a rotary loop-taker l3, and a pair of upper and lower feed rolls l4 and I6, respectively, which grip between their peripheral surfaces the marginal portions of the upper and sole of a stitchdown shoe. The needle I! is supplied with thread T which comes from a reel (not shown) and which passes over an adjustable tensioning device i8, over a pull-off 20, through a thread lock 22 for preventing reverse movement of the thread, over a lubrieating roll 24, and past a. take-up 26 on its way to the needle. The needle is actuated through a train of mechanism comprisin an element relatively movable to disconnect the needle from the driven parts of the mechanism. As disclosed in the patent to Leveque No. 1,864,510, above mentioned, the take-up and the feed rolls are also driven through said disconnectible element.

The machine is driven through a belt 28 from any suitable source 01 power. The belt 28 drives a pulley 30 which, through a clutch 32, may be coupled at will to a shaft 34 which is the main sewing shaft. The clutch 32 is actuated through 3 a yoke 36 and treadle rod 38 by a treadle 40 which is normally held up by a spring 42. Depression of the treadle 40 effects a coupling movement of the clutch members and starts the drive of the shaft 34.

The needle I2 is carried by a needle bar 44 which reciprocates in a vertical guideway formed in the frame I'll. Ciainped on the needle bar 44 is a collar 45 having 'a lug B to which is pivotally connected the upper end of a link 50. The lower end of the link 50 is pivotally connected to a forwardly extending arm 52 of a driving bell crank 54 having a downwardly extending arm 56. The bell crank 54 is fulcrumed upon a horizontal stud 58 having a. reduced threaded end 60, best shown in Figs. and 8. A nut 52 threaded upon the end Gil clamps a shoulder of the stud 58 against a boss 54 extending inwardly from the wall of the frame ID. .A driven bell crank 65 also fulcrumed upon the stud 58 has a rearwardly extending arm GB and a, downwardly extending arm ll). A collar 69 (Figs. 5 and 8), secured by a setscrew H to the free end of the stud it, retains the two bell cranks upon the stud. When the machine is to be driven, the depending arms 56 and III of the two bell cranks are latched together by a mechanism later to be described, causing the two bell cranks to function as a single lever. Pivotally connected to the rearwardly extending arm 68 by a ball joint 72 is a connecting rod 14, the lower end of which carries a bearing T5 which is mounted upon a crank 18 on the main shaft 34. Rotation of the shaft 34 operates through the crank and connecting rod above mentioned to rock the arms 68 and 52 (provided the two bell cranks are coupled) and thereby to reciprocate the needle bar.

The mechanism for ouplin and uncoupling the bell cranks 54 and it to connect or disconnect the needle from its actuating mechanism will now he described. Rotatable in a sleeve 19 (Fig. 8) carried by the depending arm 56 is a pivot pin 8|) upon one end of which is mounted a hook-shaped disconnecting latch 82 which is engageable with a. pin Bl extending from the depending arm TI). The sleeve 19, which is not shown in Figs. 2, 3 and 4, is of the same diameter and is directly in back of the hub of the latch 82, shown in those figures. When the latch 82 engages the pin 84, as shown in Fig. 1, the two bell cranks are coupled together to move as a unit, a pair of co-enaaging lugs 86 and 88 on the respective hell cranks being brought into contact at the same time. Secured upon the other end of the pin 80 is a hub 88 (-Fig. 8) having an arm 8| to which is attached one end of a tension spring 90, tending to urge the latch 82 into engagement with the pin 84. In order to provide for unhookirig the latch 82 and uncoupling the ball cranks, the latch H is provided with a tall 94 which may be engaged by a pin 96 carried by an arm 98 to rock the latch into uncoupling position, as shown in Fig. 2. The machine as so far described is similar in all respects to that disclosed in the above-mentioned patent to Leveque.

In the machine of the Leveque patent, the arm corresponding to the arm 98 is made fast to a rockshaft extending through a. bearing in the side of the machine frame and having rigidly secured to it a needle-controlled arm. The arm corresponding to the arm '98. therefore, is actuated positively by troodlo oontrolled connections to unhook the latch or to cause the latch to connect the bell cranks 54 and 65.

In the machine embodying the present invention, the treadle 40 is connected through a releasable joint with the latch 82 in such a. way that upon the occurrence of slack or broken thread, even though the treadle is held in depressed position. the driven Raid driven bell cranks BB and 5! may be uncoupled. For this purpose a sewing-thread-tension-responsive member is provided for rendering the treadle ineiiective to cause the latch to be held in latching relation with the pin 84. The connections and the releasable joint are constructed in a novel and efi'ective manner to prevent the machine from being restarted until the treadle is I eieased and again depressed and suitable additional mechanism also is provided for rendering the thread-tension-responsive member temporarily inoperative at the beginning of a new seam so that proper sewing operations may be performed in spite of the existence of slack thread.

The connections between the latch actuating arm 98 and treadle are best illustrated in Figs. 5, "6 and 7 and include a hub 99 from which the arm 9! a horizontal rockshaft I00 on which the hub b! is mounted for free rotation, a split collar 104 secured upon the inner end or the rocksha'ft FEB by a clamping screw "3 for maintaining the hub 39 in position upon the shaft, a hub I06 secured upon the shaft lllil by a clamping screw t, and other connections to be described hereinafter. The rockshaft Hill is Journaled in a bearing iii! which is integral with the side wall or the housing It,

Formed in one of "the end races of the hub W5 is a notch on into which extends a tongue llll from the hub 39. The width of the tongue Illl circumferentially with respect to the axis of the shaft Hill is less than the width of the notch "ll to afford the arm 33 a limited amount of lost motion with respect to the hub I06 and therefore with respect to the shaft ND. A torsion spring H2 wrapped around the hub "B has one end hooked about a pin ll! secured in the hub N15 and its opposite end bearing against the arm 98 to urge the arm 9! downwardly as far as permitted by the tongue 1 "I.

The releasable joint in the treadle connections is mounted on the right end of the shaft [00. which extends outside of the housing Ill. The Joint comprises a wedge-shaped cam I20 and a spring-pressed plunger I78. The cam 'I'Z'fl is carried by a collar If! secured to the shaft Hill by a setscrew Hi. The plunger 128 is slidab'ly mounted in a treadle contidlled arm in. This plunger consists of a shank if-l (Figs 4 and 5) and a wedge-shaped outwardly extending end which yieldirrgly engages the cam fill under the influerice or a compression spring I30. The shank I21 is grooved toengaeea pin to prevent turning of the shank. reely rotatable upon the shaft i'llll between the bearing f0! and the collar 1 [I is a hub 122 01 the arm m. the rear end or'which is pivotaliy connected to asieeve iziithr'eaded for purposes or adiustment upon the upper end of the treadle rod 38. It is evident that depression of the trcadle will lower the arm F24, rocking it in a counterclockwise direction, as seen in Fig. 2. and thereby, through the engagement oi the eotent I28 with the com I, will rock the ahaft WI to raise the arm l8 and permit the latch 82, under the influenced the spring M, to engage the pin 84 and thereby eta-rt reciprocation of the needle [2. Likewise, when the operator allows the treadle 40 to rise, the arm 90 will descend and the pin 96 will engage the tail of the latch 82 to uncouple the latch. However, as is shown in Figs. 3 and 4, the arm 96 has formed in it a notch I32 which receives the sleeve I9 and, until this sleeve is moved into a position wherein it can enter the notch I32, the arm 90 will be held up by the engagement of its lower edge with the sleeve. The purpose of the torsion spring H2 and the provision of lost motion between the recess I00 and the tongue H0 is to enable the arm 90 thus to be yieldingly held up until the needle reaches the highest point of its travel, at which time the sleeve 19 will be directly below the notch I32 and the arm 98 will thereupon drop into position for disengaging the drive of the needle,

The mechanism for rendering the releasable Joint ineffective and for stopping reciprocation of the needle in case the thread breaks will now be described. It comprises a thread engaging tension-responsive roll I36 freely rotatable up n a shaft I38 carried by the upper end portion of a rod I40 which extends downwardly througha bearing I42 formed in the top wall of the housing I0. The roll I36 is urged upwardly by a compression spring I44 surrounding the rod I40 interposed between the bearin I42 and collar I46 secured on the rod I40. The lower end of the rod I40 is pivotally connected to an arm I48 of a bell crank I50 having a hub which is free to rock upon a stationary pin I4I secured in the housing I0. A downwardly extending arm I52 of the bell crank I50 is pivotally connected to one end oi a link I54. housing I0, engages the arm I52 to limit upward movement of the rod I40 under the influence. of the spring I44. The opposite end of the link I54 is pivotally connected to a push rod I56 which is supported on a pin I58 secured in an arm I60 extending from the hub I06. To actuate the push rod upon loss of thread tension, the bell crank 54 has a pin I62 which, in the course of its downward oscillating movement, may or may not engage the free end of the rod I56, according to the positions of the tension-responsive roll I36 and the rod I55. During the normal running of the machine the tension oi the thread T holds the roll I36 down low enough (as shown in Fig. 3) to keep the rod I56 out of the path of the pin I62. However. if the thread should break, the spring I44 will raise the arm I40 and rock the bell crank I50 in a clockwise direction and there.- by, through the link I54, will swing the rod I56 upwardly a short distance in a counterclockwise direction. Then the pin I62, upon its next downward movement, will strike the end of the rod I56 and will operate, through the rod I56, to rock the arm I60 and thereby the hub I06 in a clockwise direction to cause the arm 96 to drop into uncouplin position as soon as the needle reaches the top of its stroke. While the shaft I00 will turn with the hub I06, the detent I26 will yield to avoid transmitting any shock to the operator through the treadle, Fig. 4 shows the position of the parts after the thread has broken or become slack. The rod I56 has just received a downward thrust from the pin I62. This downward thrust has caused the shaft I00 to turn in a clockwise direction, raising the cam I up past the yieldin detent I26. The arm 98 will now drop as soon as the bell-crank arm 56 completes its stroke to the right,

The operator will, of course, when he sees that reciprocation or the needle has stopped, release the treadle and stop the transmission of power A stationary pin- I53, secured in the through the clutch 32. As the treadle rises, the detent I28 will slip up over the cam I20 to its normal position (as shown in Figs. 2 and 3).

However, in order to permit the starting of the machine after the operator has rethreaded the needle, the roll I36 must be lowered from its raised position, otherwise the releasable joint will again be rendered inefiective and needle reciprocation stopped. To this end, there is provided a latch I82 which isfreely pivoted upon a horizontal pin I64 extending inwardly from the arm I24 and passing through an opening I86 (see Fig. 5) formed in the wall of the housing III. A torsion spring I88 urges the latch I82 in a clockwise direction, as seen in Figs. 2, 3 and 4. Formed on the upper portion of the latch I82 is a. hook I89 (Figs. 3 and 4) which, as shown in Fig. 2, engages the free end of the arm I48 so as to be able to draw the arm downwardly when the treadle is later depressed. Such movement of the arm I48 acts through the link I54 to swing the rod I56 out of the path of the pin I62, thus preventin'g'the releasable joint from being dis connected. However, the tension-responsive roll I36, as long as it is held down positively by the latch I82, is unable to perform its function,

In order to restore the thread-tension-responsive roll I36 to operative condition there is provided a rod I90 pivotaliy connected at one end to the bell crank 54 and having its opposite end free. Therod I90 is supported by a guide I92 which, for convenience, is carried by the bell crank I50, the guide I92 having an eye through which the rod I90 is freely slidable. As soon as the operation of the machine begins, the bell crank 54 will be rocked to move the needle down and, in the course of this movement, it will force the rod I90 to the left, as seen in Figs. 2, 3 and 4. The free end of the rod I90 will thereupon strike against a surface I94 on the latch I82 and swing the latch to the left, thereby releasing the arm I48 and permitting the roll I36 to rise to its normal operating position, as shown in Fig. 3.

Certain members of the mechanism for actuating the sewing thread pull-off 20 shown in the drawings (and not yet mentioned) are like corresponding members disclosed in the above-mentioned patent to Leveque. These members are shown herein because they are carried by or connected to portions of the mechanism which embody the presentinvention, and their illustration simplifies and renders obvious the relation of the mechanism of the present invention to the complete machine disclosed in the patent to Leveque. The particular members in question are as follows: an'arm I10 extending rearwardly from the hub I06 and serving, through a link I12, to operate a lever I60 which carries the pull-off 20.

The general operation of the machine will be apparent from the foregoing description and reference to the Leveque patent. The machine is shown in Fig. 2, after stopping by release of the treadle, in a position of rest with the arm I43 in its up position but engaged positively by the latch I82, the-treadle and the latch I62 being also in their up position. The operator depresses the treadle to start the machine and as the treadle is depressed the latch I62 and the roll I36 will be drawn down with it. After the first stitch the latch is'released by the rod I90 and the roll I36 becomes operative, as shown in Fig. 3. If the thread breaks. the release of its tension against the roll I36 causes the spring I44 to raise the rod I40, thereby swinging the arm I56 in a c0unterclockwise direction from the position shown in scend' and release the latch: pim Ni and: stop reciprocation= orthie necdle with themeddie at its highest poihiz. The-operatmr nmyrtiimn rethread the needle:or othenwisa adziizstzdiemas chine and continue in. the mammar- -idc scribed.

Having described my inventiomtwiiztch' claim: as new and; desire tttsmmraeby-Letiiarse mean the United Statesis:

1 In asewing; machine, iii-recombination stitch forming devices, a; maimsemingsshantzmdi trains oi: driving mechanism for mine the. stitch forming deVicB-l from; thesevdhge sham at. least one of saiditrainsotim mousing: coupling elements relativeiyr maple? to, one of' the actuated: devices: h). amii disconnect: it: from the shaft; and yiei'dingr depbicttmdlni connections acting when: depcesscdi to causmtiie: coupling elements tohe he!!! inlcmmactingrrelinthread for rendering'theatremdie cnnnectihmineffective to cause the; coupling elements to limheik in connecting relation;

2. In a sewing machine; fliecomhinaflmtvidth:

trains of driving mechanism; tin:- actuatingatime stitch forming devices from thmseiidng siiaflumti least one of said trainsxoti mechanism comprising: coupling elements relatively movabie tiruonnocti one of the actuated devices-:toandi disconnoett iz from the shaft, yieldingdepressi'bie treadlkcmrp nections acting when depressed'to'cause themed-- pling elements to be held in connecting; mitttiimi and a sewing-thread-tensl0n'-resp0nsive member: of a releasable joint'l connecting the treadibcorr nections with the coupling elements oi'the driving mechanism constructed and azmngedttnhe released by actuation of the tensitin -responsive member under loss of "threaditension and teamed; ineffective to cause the coupling'eicmenifs:tir has held in connectingrehartinrrvvhilletiic nections are maintainedinadepressedtpesitiom 3. In a sewing machine: fiicx'ccmbinatiomwithr stitch forming devices. a'- main semingsshai't and trains of driving mechanism; for mflhgt-BBP stitch forming devices fiomthe sendhec shaft; least one of said trains ofmechanism comprising coupling elements relativeiy movabie to conneoti one of the actuated devicess tomnd disconneot-itt from the shaft, yielding depressi-ble ticadlt 00!! nections acting when depressed tce cause the coupling elements to be heiti i'n connecting role, tion, a sewing-thread-tensio'n-rcspousivamember. and a releasable jointconncctlng' tiie treadiee connections with the coupling elements of the driving mechanism; of mechanism actuated? by the thread tension responsive-manner to release the joint connecting the treadie -cnnneoticns witii the coupling elements of tiiedtiving mechanism 65* upon loss of thread tension;

4. In a sewing machine, thercomiiitratibmvtitii: stitch forming devices, a mainwsewihgrsiiaft-t and! trains of driving mechanism" fbr' actnating'thw stitch forming devices from the sewing-shaft, at m least one of said trainsof'mechanlsm commisinw driving and driven parts and coupiimp elements: relatively. movable to connect andidisctmnect' said parts. yielding depressihies trenches connections acting when depressed to caarsut-liwcoupiihm-elb- TE 8 mtsztwheehelmimcuzmeetingreiaticnmsewm inrwm-tensioneresponsive'memben and-a roles ahim joint connecting; the treactle" connections leasing said joint to disconnect the driving and: driven. parts; when the; responsive: member in actuatcdi-by loss 'of thread'itensiom B- i aisewing machine, the comliination mm.

driving and driven. parts and a coupling eiemomi relativeiitmovniile to connect and disconnect saini pacts-l. yielding depressible: treadle connections actings'whem depressed tdcause the coupling eiia meat .fimbe held in. connecting relation; a: sewin-- thresdtensioni-responsive. member, a releasable! joinacunnectmgthe treadlesconrrectionswititthm coupling element-o1 the: drivingmechanism, andi normally: inoperative means; actuated by: the? chiivenpact ot'tiic driving mechanism for releas irrgrsaid jointito disconnect the driving and. driven: tion, of means responsive iir-tensicmemthezsewinza pants when the responsive memberi's antuated iiw lbss thread tension; of meansior maintaining said mieasingmeans' inoperative forabrieffperibdfi alter the tread-1e connections have again been a depressed to cnable the driving and. driven parts stitch forming devices;v a mains sewing siiaftamfli offsaald tmin otmechanism towem-ain connected: notwithstanding the initial lack. of tensionih the sewing-thread.

67 In a; sewingmachine; the combinationwitiii fi-stitcii forming devices, a main sewing shaft and trains-of driving mechanism for'actuating the stitch-forming devices" fromthe sewing shaft, at least one of said trains of mechanism comprising drivingand driven parts anda coupling element lib reiatively movable to-connect and disconnect-said parts, yielding depress-ible treatdle connections= acting when depressed to cause the coupli'ngele ment to Belieldin connecting'relation, a: sewing thread tension-responsive member; a releaselal'e- 415 Joint connecting the treadle'connectionswith the coupling element of the driving mechanism; nor ma'ily' inoperative means" actuated by' the diiven' part of the-driving mechanism fbrreliaasingsaid? joint to disconnect the driving and driven parts? 58* when the responsive member is actuatediiy loss of'thread tension; an-dmeans' for preventingsaid tension responsive member from actuating said" releasing means after the treadle connections have againbeen depressed to enaifile the driving" 55? and driven parts of said train of mechanism to ammeans" and" thereby enabling said tensiom responsive means to control the' driveof said drivenpart;

7. Iir a sewingmachine, sewing instrumentalb ties; driving mechanism, a latch through which the drive of'said driving mechanism is: trans= mittedtosaid sewinginstrumentalities, operatm controlledmeans forconnectlngjzmd disconnecting said latch tostart andstop the transmissiurr of drive to the sewing instrumcntalities at Willi means responsive tothe tension of the thread operated upon by'the machine'i'or disconnecting" said latch when the thread breaks, and means for rendering saidtension-responsive'means'tempoi-arily inoperative after said latch has againi been connected by said operator-controlled means, thereby enabling the machine to run until tension develops in the thread.

8. In a sewing machine, sewing instrumentalities, driving mechanism, a latch through which the drive of said driving mechanism is transmitted to said sewing instrumentalities, operatorcontrolled means for connecting and disconnecting said latch to start and stop the transmission of drive to the sewing instrumentalities at will, means responsive to the tension of the thread operated upon by the machine for disconnecting said latch when the thread breaks, means for rendering said tension-responsive means temporarily inoperative after said latch has again been connected by said operator-controlled means, thereby enabling the machine to run until tension develops in the thread, and means operated by said sewing instrumentalities after said latch has been connected for rendering said tension-responsive means operative.

9. In a sewing machine, sewing instrumentalities, driving mechanism, a. latch through which the drive of said driving mechanism is transmitted to said sewing instrumentalities, a device engageable with the thread operated upon by the machine, said thread-engageable device being constructed and arranged to perform yieldingly an operative movement upon relaxation of the tension of the thread by breakage thereof, means operated by said device for disconnecting said latch to stop the drive of the sewing instrumentalitie when the device performs its operative movement, and a latch for holding said device against said operative movement to enable the machine to start running again regardless of the tension of the thread.

10. In a sewing machine, a needle bar for bolding a needle to which a thread is supplied, an oscillatory driving member, connections between said driving member and said needle bar for driving the needle bar in synchronism with the movements of the driving member, a releasable cou pling in said driving connections, and tensionresponsive means controlled by said thread for releasing said coupling and thereby stopping the drive of said needle bar upon breakage of the thread.

11. In a sewing machine, a needle bar for holding a needle to which a thread is supplied, an oscillatory driving member, connections between said driving member and said needle bar for driving the needle bar, a releasable coupling in said driving connections, movable means for releasing said coupling to disconnect the needle bar from the driving member, means for holding said releasing means from operative movement to disconnect the needle bar until the needle bar reaches a predetermined position in its stroke, and tension-responsive means controlled by said thread for yieldably urging said releasing means into operative position to cause the releasing means to disconnect the needle bar from the driving member as soon as the needle bar reaches said predetermined position.

12. In a sewing machine, a needle bar for holding a needle to which a thread is supplied, an oscillatory driving member, connections between said driving member and said needle bar for driving the needle bar, a releasable coupling in said driving connection, tension-responsive means controlled by said thread for releasing said coupling and thereby stopping the drive of said needle bar upon failure of tension resulting from breakage of the thread, and means for preventing operation of said releasing means when the machine is started again until tension has developed in the thread.

13. In a sewing machine, a needle bar for holding a needle to which a thread is supplied, an oscillatory driving member, connections between said driving member and said needle bar for driving the needle bar, a releasable coupling in said driving connections, tension-responsive means controlled by said thread for releasing said coupling and thereby stopping the drive of said needl bar upon failure of tension resulting from breakage of the thread, means for preventing operation of said releasing means when the machine is started, and means operated by said connections on the driven side of said coupling for rendering the preventing means inoperative and thereby rendering the releasing means operative after movement of the needle bar has started again.

LLOYD G. MILLER.

REFERENCE S CITED UNITED STATES PATENTS Name Date Haas July 30, 1940 Number

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