US2502058A - Shoe sewing machine - Google Patents

Description

A. R. MoRR|LL. sHoE SEWING 'MACHINE March 2s, 195o 3 Sheets-Sheet 2 Filed May 29, 1948 Manchr 28, 1950 4 A. R. MORRILI.4 v 2,502,058

-sHoE SEWING MACHINE Filed nay 29, 1948 a' sheets-sheets @aim/70 Patented Mar. 28, 1950 SHOE SEWING MACHINE Alfred R. Morrill, deceased, late of Woodstock, vt., by Ruth W. Morrill, administratrix, Woodstock, Vt., assigner to United Shoe Machinery Corporation, Flemington, N.

Jersey J., a corporation of New Application May 29, 194s, serial No. 30,109

`The present invention relates to improvements in shoe sewing machines, and more particularly to animproved thread tension control mechanism which is particularly adapted for use in shoe sewing machines for releasing and holding the thread tension in the released `condition for the sewing of a plurality of stitches upon the starting of the machine.

The invention is shown in a preferred form as embodied in an automatic shoe sewing machine ofthe general type illustrated in the patent to Morrill No. 2,359,662, having a chainstitch sewing mechanism adapted for sewing a chainstitch seem in which the chain is laid on the outer or welt side of the seam, and an automatic shoe support including a jack and supporting and actuating mechanism for positioning a jacked shoe with relation to thesewing mechanism and for transferring the operation about the sole marn gin of the shoe. In the illustrated machine, provision is made for the automatic severing and clamping of the thread and for the release of the thread tension when the machine is stopped, and for re-establishing the thread tension in active operation only after the rststitch of the new seam has been sewn when the machine is Iagain started. Reference maybe had also to the disclosure of Morrill Patent No. 2,359,663, in which .lprovision is made for re-establishing the thread i;A tension in active operation only after a plurality vof" initial stitches of the new seam have been sewn when the machine is started. vThe thread tensioning device of the illustrated construction is of the general type which com- "prises a tension wheel about which the thread passeaa tension control element in the form of Ta, friction brake lever movable between tension engaging and tension release positions, and spring means tending to bias the tension control element to its tension engaging position.

y Itis the object of the present invention to provide/,fia vnovel and improved mechanism to release and to hold the thread tensioning device in released position during the sewing of at least the rsttwo stitches of a new seam, and thereafter to ite-establish the tensioning device in operation. `In accordance with the invention, a novel construction and arrangement of the mechanism for releasing and for re-establishing the thread tension is provided, which consists of two independently'operated latching devices which operate consecutively to hold thetension control element of the tensioning device in its inoperative position during the sewing of the first two stitches of a seam,l one of said latching devices being arranged to: be automatically releasedby the oscillatory a claims. (ol. 11a- 59)l movement of the bell-crank clutch shifting lever during the formation of the first stitch of the new seam, and the other of said latching devices being arranged to be automatically released by the 0scillatory downward movement of the take-,up lever upon completion of the second stitch to permit the engagement of the thread tension.

` With the above noted and other objects in View as may hereinafter appear, the several features of the invention consist also in the devices, combinations and arrangement of parts hereinafter described and claimed, which together with the advantages to be obtained thereby will be readily understood by one skilled in the art from vthe following description taken in connection with the accompanying drawings, in which Fig. 1 is a View in left side elevation of an automatic inseam s hoe sewing machine, illustrating particularly the sewing head and portions of the motor drive with the parts in stop position, only so much of the machine being shown as is believed necessaryvto illustrated the connection of the present inven-f tion therewith; Fig. 2 is a plan view of substantially the parts shown in Fig. 1, but with portions broken away and sectioned to illustrate particularly the construction and operation of the sewing cam stop motion mechanism; and Figs. 3, 4 and 5V are somewhat fragmentary views of the thread tension release mechanism illustrating successive positions of these parts taken during the sewing of the rst two stitches of the seam; Fig. 3 illustrating a position in which the machine stop arm has moved out of its slot and the thread tension brake lever is supported by the release latch controlled by the oscillatory movement of l the bell-crank clutch shifting lever; Fig. 4 illus--A prises generally a sewing head having a curved lar to the machine illustrated in the patent-to.'

Morrill No; 2,359,662 above referred to, and comhook' needle `arranged to enter the work from the welt side, and associated thread handling and" lilorkguidingdeviccs for sewing the insole of a welted shoe, a shoe supporting jack and pattern control mechanism for imparting turning, tip-1 ping and feeding movements to the jack and shoe supported thereon to transfer the point of operation about the margin of the shoe sole, and driving and stopping mechanism arranged to operate automatically at the completion of a sewing operation to release and t move the jacked shoe away from the sewing mechanism, and to return the several operating mechanisms of the machine to a convenient starting position.

Only so much of the machine has been illustrated and will be hereinafter described, as is believed necessary to illustrate the connection ofthe present invention thereto.

In the drawings, the sewing head 22 of the machine is illustrated in Fig. 1 together with a portion of the motor housing 24 mounted thereon, and a small portion of the column 28;on which the sewing head is carried. The drive for the machine is taken from a motor 5:2 in the housing 24 directly downwardly to the sewing head 22 to the stop motion of the machine and to the Asewing cam shaft 54, and thence downwardly to the pattern mechanism ofthe machine (not here shown). As generally indicated in the drawings (Figs. l and 2), the armature shaft 58 of the motor is connected through reduction gears 58, 68 to drive a vertically arranged driving shaft 62'which'is in turn connected by means of gears 54, 88 to drive an externally coned clutch member (iB/forming the driving element of the main driving clutch. The clutch member 68 is supported against movement axially and is sleeved to a vertically arranged mainv drive shaft 18 to turn loosely thereon. These parts are driven continuously. The cooperating driven element of themain'driving and stopping clutch comprises 'an internally coned clutch member 12 keyed to turn with and to slide on the drive shaft 18. A compression spring (not shown) coiled about the drive shaft 18 tends normally to hold the driven clutch member 12 in a raised disengaged position with'relation to the driving clutch mem'- ber 68. The driven member 12 of the main starting and stopping clutch is arranged through its splined connection with the vertical drive shaft 18 to drive the pattern mechanism of the machine including the pattern cam shaft. The driven clutch member is also connected to drive the 'sewingv cam shaft 54 through the meshingl engagement of a spiral gear 14 formed on the outer periphery of the driven clutch member 12 with aspiral gear 16 secured to the sewing cam shaft lill.`r Disengagement of the main Ydriving clutch will operate to disconnect the drive to each of the sewing head and the pattern mechanism of the machine. y

In stopping the machine, the sewing camshaft is vfirst brought to a gradual stop, and is then driven to a predetermined position in a reverse direction by means of slow speed reverse driving connections and a friction clutch mechanism on the sewing cam shaft. The sewing cam shaft stopping and reversing clutch mechanism is arranged to be thrown into operation as the main clutch 12 is disengaged in stopping the machine. As shown in Figs. 1 and 2, the reverse driving connections comprise a forwardly extending reverse drive shaft 18 which is continuously driven from the gear 84 through the engagement therewithof a worm gear 88 on the shaft 18. An extension 19' coupled to the forward end ofthe reverse drive shaft 18, carries a worm 82 which. meshes with a worm gear 84 loosely sleeved on the sewing cam shaft 54. The gear 84 has formed integrally therewith, an internalcone-shaped internal clutching surface 88; and forms the driving 4 element of the sewing cam shaft reverse and stopping clutch. The cooperating driven member of this clutch consists of a clutch element 88 which is provided with a cooperating external coned clutch surface, and is keyed to turn with and to slide axially on the sewing cam shaft 54. A compression spring 98 coiled about the sewing cam shaft 54 and arranged to bear at one end against the sleeve hub of the driven clutch member 88 and at its other end against a disk 92 secured to the camshaft tends normally to maintain theV clutch in open position. The sewing cam shaft reversing and stopping clutch is actuated by means of a bell-crank clutch shifting lever 94 which carries on one arm thereof a roller 96 engaging in a cam track 98 in the sleeve hub of the shiftable clutch member 88. During normal operation in which the clutch is disengaged, the bell-crank ,clutch shifting lever 94 has an idling motion determined by the contours of the cam track 98.v At the same time that the main clutch 12 is disengaged in stopping the machine, a vertically arrangedjlock bolt |88 carried in the rearwardly extending end of a lock bolt carrier or slide |02 is permitted to engage within a socket formed in the free end of the' bell-crank 94; The slide |82 is supported in a casing |84, and is acted upon by va compression spring |86 coiled about a reduced portion of the slide which tends to maintainjthe same in a fully extended rearward position. During this operation of stopping and reversingthe sewing cam shaft, the bell-crank clutch shifting lever 94 and slider |82 will bel moved forwardly against the pressure of the spring |88, and then rearwardly to the final stop position of the machine'illustrated in Fig. 1. v

In order to stop the sewing cam shaft 54 in its predetermined stop position, a stop arm |88 is provided which is loosely supported at 'its upper end on a transversely extending pivot shaft H8 located substantially above the sewing cam shaft,y

and at its lower end is providedwith a roller ||2 for engagement with a camdisk H4 on the sewing cam shaft 54. During the normal rotational movement of the sewing cam shaft 'in a counterclockwise direction as viewed' from the left side of the machine, the roller H2 is held out of engagement with the cam disk H4. However, during the reverse'movement of the sewing cam shaftV in stopping the machine', the roller' H2 is arranged to engage with and ride inwardly in a stop cam groove H6, 'so that as the roller H2 reaches the bottom of the groove H6, the cam shaft is brought t0 a positive stop;

rPhe operation of the main starting. and ystopping clutchv 12 of the machine and of the lock rock shaft |28'is rendered operative vbythe down-` ward .movement of the treadle rod .to An iovefthe, main clutch member -12A downwardly into; engaging position. the-lock bolt |88, there is'also secured tothe rock shaft |28,` avdownwardl'y and rearwardly exev tending. lever armv |138 whichfca-.rriesaarollerslSl' For. :controlling the operation Tofadapted for engagement against a cam surface formed on a lever arm |34 secured `to a rock shaft |36 parallel to and beneath the rock shaft |20. A lever arm |38 on the rock shaft |36 is connected by a link |40 with the lower end of the lock bolt |00. A compression spring |42 coiled about a reduced portion of the lock bolt and seated at its lower end in the slide |02 acts to force the lock bolt |00 yieldingly upward. A tension spring |44 connected between the lever arm |30 and a point on the machine frame tends to rock the shaft |36 in a direction to permit the disengagement of the main clutch and the movement of the lock bolt upwardly into engagement with the socket in the clutch shift lever 94.

Downward movement of the treadle rod ||8 in starting the machine, will act as above noted, t0 engage the main clutch 12 and at the same time to effect a withdrawal and disengagement of the lock bolt |00 from the clutch shift lever 94, thus permitting the sewing lcam shaft reverse stop motion clutch member 88 to be moved under the pressure of its spring to an inoperative running position.

The sewing mechanism of the machine, as indicated generally in Fig. 1, consists of a chainstitch sewing mechanism adapted for sewing the upper and welt to the insole of a welt shoe, the parts including a curved hook needle |50, a looper |52, a thread finger |54, a take-up lever |56, a welt guide |58, and a channel guide |60. In the illustrated construction, the thread finger |54 takes the form of an arcuate member slidably supported within a casing |62 and arranged upon stopping the machine, to be moved rearwardly an abnormal amount to cause the thread to be firmly gripped by a normally inoperative cooperating anvil member. The gripped thread is severed from the work by means of a thread severing knife |64. For a full description of this mechanism which forms specifically no part of the present invention, reference may be had to the patent `to Morrill No. 2,359,662, dated October 3, 1944, illustrating a similar construction and arrangement of the sewing instrumentalities.

The take-up lever |50 of the machine, as best shown in Fig. 1, is supported to turn on a pivot |68 and is given a continuous oscillatory movement by means of a cam on the cam shaft 54. The take-up lever is arranged to act against a thread tension provided by a tension wheel |10 (see Figs. 1 and 2) to draw in the previous stitch, and thereafter to draw off additional thread from the supply to the tension wheel. Tension is supplied by means of a brake lever |12 and brake shoe |14 which engages with a friction drum secured to turn with the tension wheel |10 under variable pressure determined by a tension spring |16 connected between the brake lever |12 and take-up lever |56. The brake lever |12 is rigidly secured on the pivot shaft ||0 to turn as a unit therewith. As shown in Fig. 1, the thread drawn from the supply passes around the tension wheel |10, and thence around an idler pulley |18, around a take-up pulley |80 on the take-up lever |55, around an idler |82, and thence to the looper |52.

In accordance with the invention, mechanisms are provided which operate in a novel and improved manner to control the position of the thread tensioning assembly including the brake shoe |14, brakelever |12 and rock shaft ||0 to cause the thread tension to be released when the machine is stopped, and thereafter to be reestablished when the machine is again started only after the rst two stitches have been formed.

Mechanism provided for controlling the position of the thread tensioning assembly includes a downwardly extending arm |84 which is secured to the rock shaft 0 and which is actuated by the operation of the lock bolt mechanism in stopping the machine to disengage the thread tension. The arm |84 at its lower end is arranged to be engaged by an abutment |86 on the lock bolt carrier |02 during the initial forward movement of the lock bolt carrier, so that the rock shaft l0 and brake lever |12 are rocked in a counterclockwise direction as viewed in Fig. l, to disengage the friction brake shoe |14. The thread tension brake assembly including the brake lever |12, shoe |14 and rock shaft ||0 are thereafter held positively in the fully disengaged position of Fig. 1, when the machine is stopped by the operation of the stop arm |08 previously described, which is loosely supported on the rock shaft ||0. The reverse movement of the cam shaft 54 during the operation of the machine stop motion causes the stop lever 08 to ride into its slot |6 so that it is rocked in a counterclockwise direction, thus causing the abutment adjacent the base or pivotal support of the lever to engage and to move a stop pin |90 formed on a yoke-like extension |64 rigidly connected with thebrake lever |12 and rock shaft ||0. The brake lever |12 and shoe |14 are forced in a counterclockwise direction to the nal stop position shown in Fig. 1. It will be evident from a consideration of Figs. l and 2, that the yoke-like extension |94 is formed integrally with the brake lever 12, and passes around the tension wheel |10 to provide a rigid support for the pin |90 at the opposite side of the tension wheel from the brake lever |12.

When the machine is started, the forward rotation of the cam shaft 54 in a counterclockwise direction as shown, for example, in Fig. 3, causes the roller ||2 to ride out of its slot I6 to release the pin |90 and brake lever |12 supported thereby. The brake lever 12 and thread tension brake shoe |14 are, however, held in a retracted inoperative position during the formation of the first two stitches by means of the stop arm |08 and two separate release latch mechanisms which are successively released to permit the re-establishing of the thread tension. One of the release latches referred to, is operative when and after the stop arm |03 has moved out of its slot in starting the machine to continue to support the brake lever |12 and supporting rock shaft ||0 in inoperative position while the first stitch of the new seam is formed and is drawn in. The other of the release latches referred to, is operative at the time the rst latch is released, to continue the support of the brake lever |12 and rock shaft ||0 in an inoperative position until finally released after a second stitch of the new seam has been drawn in.

The first of the release latch mechanisms referred to, consists of a release latch A200 supported intermediate its length on a stationary pivot pin 202, and at its forward end provided with a notched surface adapted for engagement with an abutment 204 on the downwardly extending arm |84. A compression spring 206 seated at one end in a recess in the lock. bolt carrier casing |04, and at its other end bearing against the underside of the release latch 200, tends to rock the latch in a counterclockwise direction to the latching position, shown in Fig. 3. At its rear end the release latch 200 carries a roller 208 adapted for engagement with a cam escaut-e surface 2|Ilfor'med in the upper side of the bellcrank lever 94. It will be noted that when the release latch 290 rocked clockwise to inoperative position as shown in Figs. 4 and 5, by movement of the roller 262 onto the high portion of its cam 2ML the forward end of the latch is engaged against a downwardly and forwardly inclined surface 2| 2 formed on the downwardly extending arm |34.

Referring specifically to Figs. l, 2 and 3, it will be seen that as the cam shaft starts its rotary movement in a counterclockwise direction upon starting the machine, and as the stop arm |08 rid-es out of its slot to release the thread tension brake lever i12, the bell-crank lever 94 is rocked in a countercloclrwise direction from the position of Fig. so that the cam surface 2H) is moved forwardly to the right, the roller 268 of release latch rides onto the low portion of its cam EIB, and the release latch 20E] is thus brought into the operative latching position to support the parts of the tension brake mechanism in the inoperative position shown in Fig. 3. At a substantially later point in the sewing cycle, the oscillatory bell-crank 94 is again rocked in a clockwise direction, causing the roller 208 to ride onto the high portion of the cam surface 2li), and thus to release the latch 20? as shown in Fig. fi. As previously noted, the

forward `end of the latch is thus brought into engagement with the inclined cam surface 2li? of the downwardly extending arm |34, so that the latch is held in its inoperative position against the pressure of its spring Zt.

After the release latch 20|) has been moved to 5.

its `released position during the formation of the rst stitch of the new seam as shown in Fig. 4, the thread tension brake lever I 12 and brake shoe |14 continue to be held in a retracted inoperative position through the operation of a second release latch mechanism which is subsequently tripped by the thread take-up lever |55 during its downward or return movement after the second stitch has been drawn in. The later operated release latch mechanism referred to, consists of a depending latch 2i@ supported on a pivot pin ZIB and provided at its lower end with a hook 22|) which is adapted to engage beneath the tip of a forwardly extending arm 222 formed integrally with the tension release brake lever |12. A torsion spring 224 coiled about the pivot pin 2|8 acts to urge the latch 2|S in a clockwise direction against the member 222. A horizontally disposed release latch trip member 226 is pivotally supported from the latch 2&6, and is provided at its forward end with a downwardly extending hook 228 which is arranged for engagement in a notch 23|) Vformed in the hub-of the thread take-up lever |56. A set screw 232 adjust-ably mounted in the trip member 225 is arranged for engagement with a cammed surface 234 on the hub of the take-up lever and acts during the downward movement of take-up lever |56 to effect the disengagement of the latch hook 228 from the notch 230 when the take-up lever I 55 has moved downwardly a sufficient distance to cause the notch 23|] and hook 22S engaged thereby to move the latch 2|6 to its released position. A stop screw 236 carried on a stationary lug 238 is adapted for a rearward position of the latch 2|6 to engage with the tail of the trip member 226, so that for a final running position of the parts shown in Fig. 5, the trip member 226 will be held inthe raised inoperative position.

The operation of the later operated latch mechanism to permit the rea-establishing of the thread tension after the second stitch of the new seam has been pulled in, is briefly as follows: The movement of the Erst-mentioned latch mechanism including latch lever 2Il|lto its released position as shown in Fig. 4, permits the parts of the thread ytension assembly including rock shaft I I0, brake lever i12 and the forward extension 222 thereof to be rocked in a clockwise direction so that the extension 222 is brought into engagement with the hook 22d of the latch 2|6, this being substantially the position shown in Fig. 4. During the subsequent operation of the machine, the take-up lever |58 moves in a counterclockwise direction to draw in and tighten the second stitch of the new seam and to draw oif additional thread from 'the supply. Thereafter, as the take-up lever :|56 starts its downward movement, the hook 228 of trip member 226 now engaged in the notch r23d-in the hub of the take-up lever |56 as shown in Fig. 4, is drawn forwardly so that the latch 2i@ and hook 220 are withdrawn from their position of supporting engagement with the extension 222, and will permit the parts of the thread tensioning assembly including the brake lever |12 and brake shoe |12 to be moved under the influence of tensioning spring |15 to the fully oper- -a-tive tensioning position of Fig. 5. As the take- -up lever I5@ now continues its movement toward the limiting Adown position, the stop screw 232 on the trip `mem-ber 225 contacting with `cam surface 231i moves the hook 228 of the trip member .out of engagement with the notch 230, so that the latch 216 is permitted to swing rearwardly in a clockwise direction into engagement with the cammed upper edge of the extension 222. At the same time the tail of the trip member 226 will 'have engaged the stop screw 236, causing this element to be rocked to an inoperative position out of engagement with the hub portion of takeu-p lever -l5S again as shown in Fig. 5. It will be noted that rthe continued rocking movement of the thread tensioning assembly including rock shaft IIliv and the depending arm |84 in a clockwise direction, will cause the forward end of the latch Edil engaging the cammed surface 2|2 to be further rocked in a clockwise direction against the pressure of its spring 286, so that roller 208 is moved wholly out -of engagement with the cooperating cam surface 2 Ill of the oscillating bellcrank.

'it will be understood that the invention is not limited to the specific embodiment shown, and that various deviations may `be made therefrom without departing from the spirit and scope of the `appended claims.

What is claimed is:

l. In an inseam shoe sewing machine operable in accordance with a lrecurring stitch forming cycle, the combination of a sewing mechanism including a sewing .cam shaft, a curved hook needle, a needle threading device, a thread tensioning device including a .tension control element movable between tension estabiishing and tension release positions. and means `biasing said element toward tension establishing position, and a driving and stopping mechanism for the sewing cam shaft, means operative in stopping the machine to support said element in tension release position, and means operative in starting the machine to re-.establish the thread tension comprising a pair of latches successively operable to support said tension control element in stepped inoperative positions, and llatch release devices `acting in different timed relation to Ithe cyclical operation of the sewing mechanism for moving said latches successively to latch release position, whereby said first latch is released to cause the tension control element to be supported by the second latch during a rst stitch forming cycle, and the second latch to be released to re-establish the thread tension during a second stitch forming c cle.

y2. In an inseam shoe sewing machine, the combination of a sewing mechanism operable in accordance with a recurring stitch forming cycle including a hook needle, a needle threading device, a thread take-up lever, a sewing machine stop mechanism including a normally oscillatory actuating member, a thread tensioning device including a tension control element movable between tension engaging and tension release positions, and means biasing said element toward tension engaging position, a thread tension control device including means operative in stopping the machine to move said element to tension release position, and means operative in starting the machine to re-establish the thread tension comprising a pair of latches successively operable to support said element in stepped inoperative positions, a connection actuated by said oscillatory actuating member during a rst stitch forming cycle to move one of said latches to latch release position, and a connection controlled by said thread take-up lever to release the second latch and thereby to permit movement of the tension control element to tension engaging position during a second stitch forming cycle of the machine.

3. In a shoe sewing machine operable in accordance with a recurring stitch forming cycle, the combination of a hook needle, a needle threading device, a thread take-up lever, a thread tensioning device including a tension control element movable between tension engaging and tension release positions, and means biasing said element toward tension engaging position, and a sewing machine stop mechanism including a normally oscillatory actuating member, and a thread tension control device including means operative when the machine is stopped to move said control element to inoperative position and to permit the tension on the thread to be re-established when the machine is started only after a plurality of stitches of the new seam have been formed, comprising a latch mechanism iirst operative when the machine is started to support the control element in inoperative position, and arranged to be released by movement of said oscillatory member in the first stitch forming cycle, and a second latch mechanism operative thereafter to support the control element in an inoperative position and arranged to be released by the movement oi the take-up lever in the second stitch forming cycle.

4. In a shoe sewing machine having a hook needle, a needle threading device, a thread takeup, a thread tensioning device including a tension control element movable between tension engaging and tension release positions and means for biasing said element toward tension engaging position, a sewing machine reverse stop mechanism including a stop arm arranged to be rocked between a running and a stop position, and a normally oscillatory stop mechanism actuating member, the combination of a thread tension control device which comprises a connection actuated by said stop arm to move the tension control element to inoperative position when the machine is stopped, a latch mechanism first operative upon return of the stop arm to running position when the machine is started to latch the thread tension control element in inoperative position during formation of the first stitch, and thereafter to be tripped into latch release position, and a second latch mechanism arranged to support the thread tension control element in inoperative position when the lrst latch mechanism is released and to be tripped into latch release position after a second stitch is pulled in and thereby to permit the return of the control element to tension engaging position.

5. In a shoe sewing machine having cyclically operable sewing mechanism including a hook needle, a needle threading device, a thread takeup, a thread tensioning device including a tensioning brake lever, and means for biasing said brake lever to tension the thread, and a sewing machine reverse stop mechanism including a stop arm arranged to be rocked between a running and a stop position, a thread tension control device which comprises a connection rendered operative by movement of the stop arm to stop position to support the brake lever in inoperative position, and a iirst and a second latch mechanism operable independently of one another for supporting the brake lever in inoperative position, and latch release devices acting in diiierent timed relation to the cyclical operation of the sewing mechanism for moving each of said latch mechanisms successively to latch release position, whereby said rst latch mechanism is operative to support the brake lever in inoperative position and is thereafter released upon completion of the iirst stitch of a new seam, and said second latch mechanism is operative to support the brake lever when the iirst latch mechanism is released and is thereafter released to release the brake lever and re-establish the thread tension upon completion of a second stitch.

6. In a shoe sewing machine having a hook needle, a needle threading device, a thread takeup, a thread tensioning device including a tensioning brake lever and means for biasing said brake lever to tension the thread, and a sewing machine reverse stop mechanism including a stop arm arranged to be rocked between a running and a stop position, and a normally oscillatory stop mechanism actuating member, the combination of a thread tension control device which comprises a connection operative upon movement of the stop arm to stop position to support the brake lever in inoperative position, a pair of latches independently operable for supporting the brake lever in inoperative position during the sewing of initial stitches of a new seam, a latch release device acting in timed relation to the cyclical operation of the sewing mechanism for rendering one of said latches inoperative upon completion of a rst stitch, and means for holding said latch in said released position, a second latch release element operative cyclically with the machine timed to move said second latch to its latch position prior to the release of the firstmentioned latch, and thereafter to move said second latch from its latch position to permit the engagement of the brake lever in the second stitch forming cycle, and means active when the brake lever is engaged to render said second latch release element inoperative.

RUTH W. MORRILL, Administratrz' of the Estate of Alfred R. Morrill,

Deceased.

No references cited.

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