US2066373A - Lockstitch sewing machine - Google Patents

Description

Jan. 5, 1937.

L. E. TOPHAM LOCKSTITCH SEWING MACHINE Original Fi led March 23, 1952 6 Sheets-Sheet l I I I nitor n e Wz'inem Jan. 5, 1937. TOPHAM I 2,066,373

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LOCKSTITCH SEWING MACHINE Original Filed March 23, 1932 6 Sheets-Sheet 6 ZZZ-glass FLJQYJZ Patented Jan. 5, 1937 UNITED STATES PATENT OFFICE LOCKSTITCH SEWING MACHINE Original application March 23, 1932, Serial No.

600,654. Divided and this 1934, Serial No. 729,617.

application June 8, Renewed March 10,

15 Claims. (01. 112-57) The present invention relates to shoe sewing machines which employ a hook needle to draw loops of needle thread through the work, and is herein illustrated as embodied in a machine of the McKay type such as that disclosed in the patent to Ashworth No. 1,914,936 granted June 20, 1933.

The object of the invention is to improve the operation of shoe sewing machines, and more particularly to provide improved devices for insuring proper formation and setting of each stitch at a uniform distance within the work during sewing and, when employed in a lockstitch machine, for causing the final stitch to remain 15 above the surface of the work where the threads may be severed simultaneously.

In the machine herein illustrated the stitch is drawn down and set by the needle thread takeup and a feature of the invention is embodied in 20 a construction utilizing a thread lock for gripping the thread between the take-up and the thread supply, as the takeup completes its thread drawing stroke, and after a supply of thread has been drawn through the tension for 25 the next stitch.

In lockstitch shoe sewing machines of ordinary construction, it has been found desirable to permit the last formed needle loop at the end of the seam to remain above the surface of the work as the machine is stopped, where the needle loop, together with the locking thread, may readily be severed by a single cutting stroke. In order to insure that a definite amount of thread will remain above the surface of the work, according to another feature of the present invention, a second thread lock is arranged between the takeup and the work for gripping the thread and. positively preventing the take-up from setting the final stitch.

Other features of the invention includes the devices, combinations and arrangements of parts hereinafter described and claimed, certain of which, while adapted for use in sole sewing machines of the McKay type, are also capable of use with other types of sewing machines.

The several features of the present invention and the advantages obtained thereby will be readily understood by those skilled in the art from the following description taken in connection with the accompanying drawings which illustrate an embodiment of the invention.

In the drawings, Fig. 1 is a View in side elevation of the complete machine; Fig. 2 is a view in front elevation, partly in section, showing the take-up mechanism and thread clamps for the needle thread of the machine shown in Fig. 1; Fig. 3 is a view in side elevation of the take-up mechanism and thread clamps shown in Fig. 2, a part of the casing and the wax pot being shown in section; Fig. 4 is a sectional plan View on an enlarged scale, of the thread locks and a portion of the mechanism for operating them in positions assumed on stopping the machine; Fig; 5 is a detail view of a part of the mechanism shown in Fig. 4, looking from the left; Fig. 6 is a detail view of a part of the mechanism shown in Fig. 4 looking from the right; Figs. 7 and 8 are fragmentary views of portions of the thread lock operating mechanisms taken along the line 'l'l of Fig. 4, and illustrating successive stages of operation; Fig. 9 is a sectional view taken on the line 99 of Fig. 1, looking from the front of the machine; Fig. 10 is a diagrammatic view showing the relative relations of the take-up and the thread locks during the sewing operation while the needle loop is passing over the shuttle; Fig. 11 is a similar view showing the parts as the stitch is being set; and Fig. 12 is a view showing the same parts just before the machine stops with thread of the final stitch not drawn into the work.

The lockstitch shoe sewing machine herein illustrated is similar to that disclosed in the application of the present inventor, Serial No. 600,654, filed March 23, 1932 of which the present application is a division. A great many of the parts common to the two machines are illustrated in the accompanying drawings, but inasmuch as they are fully illustrated and described in the above application, they will be only briefly referred to in the following description.

The illustrated machine is driven from an electric motor I2 through a clutch mechanism indicated in Fig. 1 in dotted lines. This clutch mechanism is controlled from a foot treadle M which is normally held in raised position by means of a spring IS. The clutch mechanism acts to connect and disconnect the motor with a shaft l8 and a sleeve 20 in the base of the machine, from which motion is transmitted to a vertical shaft 22 extending up to the sewing head of the machine. Rotation of the shaft 22 imparts a corresponding movement to a sewing shaft 24 for operating the needle, shuttle and other related parts.

The shoe to be operated upon is supported on an angular horn 26 having an inclined upper portion enclosing needle threading devices. Motion is imparted to the needle threading devices through a hollow vertical shaft 28 connected through suitable gears to a horizontal shaft 30 and the vertical shaft 22 driven from the motor I2.

, The sewing head of the machine is provided with a straight hook needle 32, a presser foot 34, a loop taker in the form of a, shuttle 36, to carry the needle loop over the bobbin or locking thread, a feed point 38, a take-up 40, a needle looper 42 and 'a thread finger 44, the latter of which is mounted in the horn. The upper end of the horn is constructed with the usual needle opening to permit the needle to enter the horn in receiving the thread from the looper.

The horn 26 is mounted on the machine to rotate a complete turn of 360 degrees, and is provided with a downwardly extending hollow spindle having bearings between the upper and lower ends of the spindle and the frame of the machine. The shaft 28 is journalled within the spindle of the horn to rotate about an axis concentric with the axis of rotation of the horn, which coincides with the longitudinal axis of the needle.

A feature of the present invention relates to a thread lock for gripping the thread to set the stitch uniformly through the action of the takeup 40. The thread lock and take-up are illustrated in Figures 2 and 3 in which the thread lock, hereinafter referred to as the sewing thread lock, is indicated at 46. The needle thread 41 passes from a source of supply 48, and. through a tension device 50 of ordinary construction provided with an adjustable tension nut 52 for varying the amount of tension, thence around a shaft 54 carrying the thread lock 46 loosely journalled in a bracket 56 attached to the machine, downwardly through a wax pct 58 of ordinary construction, upwardly over a pulley 60 carried by the bracket 56, downwardly around a pulley 62 at the end of the take-up lever 40 through a pulley 64 on the bracket 56, and upwardly into the horn. In order to prevent entanglement of the thread about the end of the take-up lever, the pivot about which the pulley 62 at the end of the take-up rotates is provided with an elongated spindle 66 (see Fig. 3) extending from the axis of the pulley at right angles to the line of movement of the take-up. The take-up 40 is operated from a cam 68 carried by the horizontal shaft 30 which forms a part of the operating connections to the needle threading devices in the horn. The take-up is fulcrumed on a shaft I0 provided with a headed portion and secured on a bracket 12 attached to the machine frame. Thread drawing and surrendering movements are imparted to the take-up through connections between the take-up and a cam slot 14 formed in the cam 68, which connections include a bell-crank "I5 formed with a sleeve portion 18 fulcrumed on a shaft 00 secured to the frame of the machine, and a link 82 connected between the take-up lever and one end of the bell crank. The other end of the bell-crank carries a cam roll 84 engaging the cam slot 14. One end of the link 82 is directly pivoted to the take-up lever 40, and the other end is loosely pivoted on a stud 86 clamped within an adjusting slot in the bell-crank. The sleeve I8 of the bell-crank is loosely mounted on the shaft 80, and is prevented from displacement by a collar 88 clamped at the end of the shaft.

The thread lock 46 is actuated to grip the thread between the take-up and the supply during each thread drawing stroke of the take-up as it reaches the lower portion of its stroke. The thread tension 50 offers sufficient resistance to cause the take-umin moving from the position indicated in Figs. 2 and 10, to draw loop of needle thread from the shuttle toward the work. As the needle loop approaches the work, it engages the locking thread, indicated at 90, and draws it against the work. Thereafter, the resistance offered by contact of the thread with the work exceeds the resistance offered by the thread tension, so that a supply of thread is drawn through the tension before the take-up reaches the end of its thread drawing stroke. Just before the end of the take-up stroke is reached, the thread lock 46 is applied, and further movement of the take-up draws the needle loop a uniform distance into the work against the thread lock 46, as shown in Fig. 11. Thus, the three operations of drawing the needle loop against the work, measuring thread from the supply, and setting the stitch, are accomplished during a single stroke of the take-up.

The thread lock 46 is actuated to grip the thread just before the needle thread take-up 40 reaches the end of its thread drawing stroke by a cup-shaped-cam 92,. shown in Figs. 2 and 4 adjustably secured in a recess in the cam 60 by a set screw 94', and connections actuated by the cam comprising a lever 96 having a cam roll 98 at one end arranged to engage the cam 92, the shaft 54 which supports the thread lock 46, a spring I00 surrounding the shaft and a block I02 secured to the shaft 54 by a set screw I04 (see Fig. 4). The thread lock 46 is formed as a washer movable toward and from a shoulder I06 formed on a sleeve I08 surrounding the shaft 54 and loosely fitting within an opening in the bracket 56. The shaft 54 is mounted in the bracket 56 to both oscillate and move freely 'in a longitudinal direction. The lever 96 is clamped by means of a bolt IIO to the shaft 54 to oscillate the shaft when the cam roll 98 is engaged by the cam 92. The block I02 is provided with a pair of projections II2 to cooperate with similarly shaped recesses II4 contained in a block II6 mounted on the bracket 56 and is resiliently pressed by the spring I00 compressed between the block I02 on the shaft 54 and a washer II8 thrusting against the bracket 56 to cause the thread lock 46 to grip the thread against the shoulder I06. As the shaft 54 is oscillated by the cam 92, the projections I I2 rise part way out of the recesses II4, moving the shaft 54 longitudinally to release the thread at the proper time to allow the take-up to measure thread during its thread drawing stroke. The cam 92 is so proportioned that the time in which the cam roll is released to move under the action of the spring I00 and the projections 2 enter the recesses II4 occurs just before the take-up has completed its stroke. In order to adjust the timing, the block II6 (see Fig. 5) is adjustably secured to the bracket 56 by a bolt I 20 slidably arranged in a slot I22 in the bracket.

1 In accordance with another feature of the invention, in order to simplify the act of severing the thread at the end of a seam, the loop of needle thread of the final stitch is positively prevented from being drawn into the work and is held in a position shown in Fig. 12, through the action of a second thread lock in the form of a washer I24, hereinafter referred to as the final stitch thread lock. This second thread lock comprises the washer mounted loosely on a shaft I26 to be moved, in gripping the thread, toward and from a shouldered sleeve I28 surrounding the shaft. The sleeve I 28 is loose on the shaft I26 and slides freely in a longitudinal direction in an opening in the bracket 56 but is held against angular rotation by a pin I30 projecting from the bracket 56, and passing through a slotted projection at one side of the sleeve I28.

In order to operate the second thread lock I24 efiectively to grip the thread, it must act during the thread drawing stroke of the take-up 40, and for this purpose the shaft I26 is operated by a cam I32 secured to the end of the shaft 30. The shaft I26 carries an arm I34 fixed to its inner end which is provided with a cam roll I36 in position to be acted upon by the cam I32. The shaft I26 is loosely mounted in the bracket 56, and is moved longitudinally by the action of a spring I38 surrounding the central part of the shaft. The spring is compressed between a block I40 clamped by a set screw I44 to the shaft and a washer I46 thrusting against the bracket 56. The block I40 is provided with a pair of projections I48 cooperating with similarly shaped recesses I50 in a block I52 secured to the bracket 56, to impart a longitudinal movement against the action of the spring I38 as the shaft is oscillated by the cam I32. This longitudinal movement causes the thread lock I24 to move toward and from the sleeve I28 to grip the thread in timed relation with the operation of the take-up. The thread lock thus operates to grip the thread between the take-up and the work as the thread is being drawn toward the work by the take-up, preventing the take-up from drawing the last formed needle thread loop and the locking thread against the work. To adjust the timing of the second thread lock, the block I52 is adjustably secured to the bracket 56 (see Fig. 6) by a bolt I54 passing through a slot in the bracket.

In order to prevent the thread lock I24 from acting to grip the needle thread during each stitch-forming cycle of the machine, the sleeve I28 is provided with a pair of diametrically opposite recesses I56 to cooperate with projections I58 formed on a collar I60. The collar I60 is loosely mounted on the sleeve I28, and is provided with gear teeth I62 (see Fig. 2) meshing with a segmental gear I64 extending from the hub of a lever I66 loosely mounted on the sleeve I08. During normal operation of the machine, the collar I60 assumes a position diiferent from that shown in Fig. 4, and in which the projections I58 coincide with the recesses I56 on the shouldered sleeve I28, so that the space between the thread lock washer I24 and the shoulder of the sleeve is greater than the thickness of the thread. As a result, the thread is free of the lock at all times during the sewing of a seam. As the machine is brought to rest, the projections I58 are moved out of the recesses I56 to the positions shown in Fig. 4, and the thread is gripped by the thread lock, permitting the needle loop to remain above the surface 01' the work, as in Fig. 12.

It is necessary during the time in which the final stitch thread lock I24 acts, to prevent the application of the sewing thread lock 46, as otherwise the thread would be broken by the take-up. For this purpose, connections operated during the completion of the final stitch as the machine is brought to rest, operate to release the sewing thread lock 46 from engagement with the shoulder I06, and permit the application of the final stitch thread lock I24, and finally to release the thread lock I24 from the sleeve I28, simultaneously with the release of the needle thread tension, so that the work may be withdrawn a short distance from the machine before severing the thread. These connections for actuating the thread locks in their proper sequence during the completion of the final stitch are operated by a stop mechanism which is of substantially the same construction as that described in Patent No. 1,874,690 granted August 30, 1932 to Ashworth.

The stop mechanism which is rendered operative when it is desired to bring the machine to rest acts to disconnect the needle from its actuating mechanism and lock it out of operation at the top of the retracting stroke and to raise the presser foot from engagement with the work as well as to actuate the thread locks and tension device in the manner just indicated. When the foot treadle I4 is released, a horizontal shaft I68 in the sewing head (see Figs. 1 and 9), is rotated in a clockwise direction. The shaft I68 is journalled in the machine frame and carries at one end an arm I10 loosely mounted thereon. Secured to the said end of the shaft is an arm I12 connected to the treadle I4 by a link I14. This arm. is provided with a projection I16 extending beneath a rearward extension of the arm I10 and engaging said rearward extension upon the release of the treadle. The arm I10 is connected to a shaft I18 by a link I80 con nected to the arm I10 at one end and at the other end to an arm I82 fixed to the shaft I18. Release of the foot treadle also acts to Swing an arm I84 attached at the rearward end of the shaft I18 in a counter-clockwise direction as viewed in Fig. 9. The arm I84 extends downwardly, and loosely supports a pin I85 at its lower end. The pin I85 is connected to the ends of a pair of links I86 and I81 which, in turn, are connected to a lifting member I88 and a retaining member I89, respectively, loosely suspended at their upper ends from the sewing shaft 24. The member I89 is provided with an eccentric strap I90 surrounding an eccentric member I9I on the sewing shaft 24, but the hook member I88 is supported loosely on the shaft itself, so that no movement is imparted to it by rotation of the shaft. When the shaft I 18 is rocked by releasing the foot treadle at the end of a seam, the lifting member I89 is moved toward the right by the arm I84 against one arm of a T-shaped lug I92 projecting laterally from, an arm of a lever I93 loosely mounted on a shaft I94 mounted in the machine frame. The shaft I94, being rotatably mounted, is provided at its rearward end with an arm I95 secured to the shaft and arranged with a portion I96 overlying the lug I92. This movement, of course, occurs only after the motor has been disconnected from the machine, the sewing shaft continuing to rotate under the momentum of the rotating parts. As the shaft continues to turn, the hook I89 is forced beneath the lug I92 by a spring I91 surrounding the link I81. When the lever I93 is actuated, an outwardly extending arm thereon is moved downwardly to operate the thread locks 46 and I24 through a second lever I98 (see Fig. 1) and a link I99 connecting the two levers. The lever I98 is fulcrumed on abolt 200 threaded into the frame of the machine, and is formed with openings I and 202 for engagement with enlargements 203 and 204, respectively (see Fig, 4) formed at the ends of the levers 96 and I66, in the order stated, for operating the thread locks. The lever I98 is maintained in a position in which the sewing thread lock acts to grip the thread by a spring 205 connected to the machine frame, and the lever carries a pair of set screws 206 and 207 entering within the opening 2IlI to adjust the relative movement between the lever I98 and the sewing thread lock lever 96.

As the stop mechanism begins its operation, lever I93 (see Fig. 9) in the head of the machine begins its movement and the sewing thread lock operating lever 96 is rocked with the shaft 54 to release the sewing thread lock 46. This movement also moves the lever I66, rotating the projections I58 out of the recesses I56, so that as the take-up draws the final needle loop towards the work, the thread lock I24 will be operated to grip the thread, and the thread lock 46 will be held in released position. The position of the lever 99 under these circumstances is shown in Fig. '7, in which the adjusting screw 29'! is shown as rocking the lever 96 to a position in which the sewing thread lock 46 is released.

In order to release the final stitch thread lock I24 as the main sewing shaft 24 continues to rotate, the lever 93 is rocked into the position shown in Fig. 8, and a lug 298 formed on the lever 96 engages a finger 209 on the arm I34, causing the arm I34 to be operated away from a position in which the final stitch thread lock I24 grips the thread. At the same time that the thread locks are released, the tension on the thread is also released by a downwardly extending arm of the lever I98 (see Fig. 1) and a rod ZID pivotally connected to the arm of the lever. The forward end of the rod carries a perforated enlargement 2I2 which bears against the tension 59, and guides the thread between the tension and the supply. At the end of the stop mechanism operation, the lever I 98 is moved and the rod 2 II) releases the thread from the tension, so that the work may be withdrawn from the machine without resistance.

The parts thus operated are retained in position by the action of the retaining member I89 engaging the lug I92 and the spring I91 which surrounds the link I81 acting to prevent release of the retaining member I89 when the sewing shaft is brought to rest and until the treadle I4 is again depressed.

As the machine is started by movement of thetreadle I4, the shaft I68 is rocked in a reverse direction, and the retaining member I89 is released from the lug I92 against the actionof the spring 597, by an arm 2I4 carrying a roll fixed to the shaft IE8 and engaging a cam surface on the retaining member I89. The lifting member I88 is also retracted from engagement with the lug I92 by movement of the arm I82 on the shaft H6 as the treadle is depressed.

The nature and scope of the invention having been indicated, and an embodiment of the invention having been specifically described, what is claimed is: a

1. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a thread tension, a looper, a take-up acting to draw down a loop of needle thread against the tension until the resistance offered by contact of the loop with the work exceeds the amount of tension and thereafter to draw the thread through the tension from the supply for the next stitch, and a thread lock for gripping the thread between the take-up and the supply while the take-up completes its stroke to set the stitch.

2. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a thread tension, a looper, a take-up acting to draw down a loop of needle thread against the "tension until the resistance offered by contact of the loop with the work exceeds the amount of tension and thereafter to draw the thread through the tension from the supply for the next stitch, and a thread lock arranged between the take-up and the thread tension for gripping the thread between the take-up and the supply while the take-up completes its thread drawing stroke and for retaining its grip on the thread as the take-up yields up thread to the other stitchforming devices.

3. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a looper, a loop taker and a take-up, mechanism for stopping the operation of the machine with the needle disengaged from, the work, and a thread lock arranged between the takeup and the work to grip the thread and prevent the take-up from drawing the last formed loop of needle thread together with the locking thread against the work.

4. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a looper, a loop taker and a take-up, mechanism for stopping the operation of the machine with the needle disengaged from the work, a thread lock arranged between the takeup and the work, and normally inactive mechanism rendered active in stopping the machine for actuating the thread'lock to grip the thread and prevent the take-up from drawing the last formed loop of needle thread together with the locking thread against the'work. I

5. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a looper, a loop taker, a take-up, a sewing shaft and suitable connections for actuating the stitch-forming devices, means for driving the sewing shaft, means for disconnecting the sewing shaft from its driving'means and for rendering inoperative the actuating connections between the needle and shaft while the needle is at the limit of a loop drawing stroke, a thread lock arranged between the take-up and the work and normally inactive mechanism rendered active in stopping the machine for actuating the thread lock to grip the thread and prevent the take-up from drawing the last formed loop of needle thread together with the locking thread against the work.

6. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a looper, a loop taker and a take-up, mechanism for stopping the operation of the machine with the needle disengaged from the work, a thread lock arranged between the takeup and the work, normally inactive mechanism rendered active in stopping the machine for actuating the thread lock to grip the thread and prevent the take-up from drawing the last formed loop of needle thread together with the locking thread against the work and thereafter to release the thread from the grip of the thread lock.

7. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a looper, a loop taker and a take-up, mechanism for stopping the operation of the machine with the needle disengaged from the work, a thread lock arranged between the takeup and the work, a cam for actuating the thread lock to grip the thread and prevent the take-up from drawing a loop of needle thread together with the locking thread against the work as the take-up completes its thread drawing stroke, and

normally inactive mechanism for preventing the T5 thread lock from gripping the thread during sewing of a seam, said mechanism being rendered active during stopping of the machine for permitting the thread lock to grip the thread under the action of the cam and thereafter for releasing the thread from the grip of said thread lock.

8. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a looper, a loop taker, a take-up and a thread lock arranged between the take-up and the supply of thread acting intermittently during sewing to grip the thread as each stitch is set, a second thread lock arranged between the take up and the work to grip the thread and prevent the take-up from drawing the last formed loop of needle thread together with the locking thread against the work, and means for releasing the thread from the thread lock on the supply side of the take-up as the second thread lock is actuated to grip the thread on the work side of the take-up.

9. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a looper, a loop taker, a take-up, a thread lock arranged between the take-up and the supply of thread, a sewing shaft and suitable connections for actuating the stitch-forming devices comprising a cam shaft for actuating the thread lock intermittently during sewing to grip the thread as each stitch is set, a second thread lock actuated by the cam shaft to grip the thread between the take-up and the work and prevent the take-up from drawing a loop of needle thread together with the locking thread against the work, and normally inactive mechanism for preventing the second thread lock from gripping the thread during sewing of a seam, said mechanism being rendered active during stopping of the machine for permitting the second thread lock to grip the thread under the action of the cam shaft and thereafter for releasing the thread from the grip of said thread lock.

10. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a looper, a loop taker, a take-up, a thread lock arranged between the take-up and the supply of thread, a sewing shaft and suitable connections for actuating the stitch-forming devices comprising a cam shaft for actuating the thread lock intermittently during sewing to grip the thread as each stitch is set, a second thread lock actuated by the cam shaft to grip the thread between the take-up and the work and prevent the take-up from drawing a loop of needle thread together with the locking thread against the work, normally inactive mechanism for preventing the second thread lock from gripping the thread during sewing of a seam, said mechanism being rendered active during stopping of the machine for permiting the thread lock to grip the thread under the action of the cam shaft, and means for releasing the thread from the thread lock on the supply side of the take-up as the second thread lock is actuated to grip the thread on the work side of the take-up.

11. A sewing machine having, in combination, stitch-forming devices including a hook needle and a pivoted take-up lever for surrendering thread as the needle is retracted from the work and for pulling the thread through the work after the thread is released from the needle, a pulley on the take-up, and an elongated spindle extending from the center of the pulley perpendicular to the line of movement of the take-up for preventing entanglement of the thread about the free end of the take-up.

12. A sewing machine having, in combination, stitch-forming devices including a hook needle and a pivoted take-up lever for surrendering thread as the needle is retracted from the work and for pulling the thread through the work after the thread is released from the needle, a pulley on the take-up, and an elongated spindle extending at right angles to the line of movement from the take-up for preventing entanglement of the thread about the free end of the take-up.

13. A lockstitch shoe sewing machine having, in combination, stitch forming devices including a hook needle, a take-up for yielding up and withdrawing thread from the other stitch forming devices, a thread supply, a thread lock acting between the take-up and the supply to grip the thread as each stitch is being set, and means for actuating the take-up while the thread is released from the lock to cause a length of thread sufficient for the succeeding stitch to be drawn from the supply, and thereafter to set the stitch while the length of thread for the succeeding stitch remains between the thread lock and the work.

14. A lockstitch shoe sewing machine having,

in combination, stitch forming devices including a hook needle, a take-up for drawing the needle loop down to the work and for setting the stitch at the end of its loop drawing stroke, a thread lock against which the stitches are set, and means for actuating the take-up and thread lock to draw thread through the lock between the time when the needle loop is drawn down and the time the stitch is set.

15. A lockstitch sewing machine having, in combination, stitch-forming devices including a hook needle, a thread tension, a looper, a take-up acting to draw down a loop of needle thread against the tension until the resistance offered by contact of the loop with the work exceeds the amount of tension and thereafter to draw the thread through the tension from the supply for the next stitch, a thread lock for gripping the thread between the take-up and the supply while the take-up completes its stroke to set the stitch, and normally inactive mechanism rendered active in stopping the machine for preventing actuation of the thread lock during formation of the last stitch.

LAURENCE E. TOPHAM.

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