US2979001A - Lockstitch shoe sewing machines - Google Patents

Description

April 11, 1961 c. F. FITZGERALD ETAL 2,979,001

LOCKSTITCI-I SHOE SEWING MACHINES Filed Feb. 8, 1957 5 Sheets-Sheet 1 '/Z F g.1

Jnvenfors:

A Char/e5 f fi/zgem/d flrf/vur J Mum/y April 11, 1961 c. F. FITZGERALD ET AL 2,979,001

LOCKSTITCH SHOE SEWING MACHINES Filed Feb. 8, 1957 5 Sheets-Sheet 2 Char/es f Fi/Zyem/d Inventors:

April 11, 1961 c. F. FITZGERALD ETAL 2,979,001

LOCKSTITCH SHOE SEWING MACHINES 5 Sheets-Sheet I5 Filed Feb. 8, 1957 flwentors Charles F Fitzgerald Arthur J Murphy a April 1961 c. F..FITZGERALD JET'AL 2,979,001

LOCKSTITCH SHOE SEWING MACHINES Filed Feb. 8, 1957 5 Sheets-Sheet 4 {is /64 13/52 W April 11, 1961 c. F. FITZGERALD ET AL 2,979,001

LOCKSTITCH SHOE SEWING MACHINES 5 Sheets-Sheet 5 Filed Feb. 8, 1957 Inventors.- C/lar/es F Fi'fzgera/a flr'fhur ll Nurp/vy LOCKSTITCH snon SEWING MACHINES Filed Feb. 8, 1957, Ser. No. 638,986

7 Claims. (Cl. 112-36) The invention relates to improvements in lockstitch shoe sewing machines having rotatably mounted shoe entering horns similar to that disclosed in United States Letters Patent No. 1,885,927, granted Novemember 1, 1932, upon application of B. T. Leveque, and No. 1,914,- 936, granted June 20, 1933, upon application of F. Ashworth. In certain of its features, however, the invention is applicable with advantage to shoe sewing machines having rotatable shoe entering horns but not being constructed to insert lockstitch seams.

The machine of the prior patents, besides being equipped with a rotatably mounted shoe entering and supporting horn, is provided with a reciprocating straight hook needle, a loop spreader, a shuttle containing a locking thread case, a take-up, a thread lock, a needle threading whirl at the tip of the horn, and other stitch-forming and stitch-setting devices. The operation of the machine is initiated and terminated by treadle controlled driving and stopping mechanisms, the stopping mechanism of which when set in operation stops the needle at the upper end of its reciprocating stroke and the other stitch-forming devices are brought to rest out of timed relationship to the needle. In that machine the loop spreader and the shuttle also are stopped with the needle, so that at the end of a seam when all of the stitch-forming devices come to rest a spread loop of thread extends from the work to the needle after the needle is stopped in its uppermost position. This loop of thread ordinarily is severed at a position close to the upper surface of the work but must be unhooked from the needle and loop spreader, so that the length of thread extending from the tip of the horn will be sufficient when drawn back into the horn to insure proper starting of a new seam. Special precautions also must be taken and skill exercised in severing the thread and unhooking it from the needle at the end of a seam. Often, damage to the thread results, so that in starting a new scam the thread end is drawn back through the whirl at the tip of the horn with the result that th machine must be rethreaded.

The objects of the present invention are to produce a lockstitch shoe sewing machine of the McKay type, which may be operated reliably and uniformly at speeds at least as high as those reached by the prior patented machine, and in which the attention paid and skill exercised by the machine operator in severing the thread are far less than required in the prior machine, and wherein all danger of damage to the thread remaining in the machine and necessity for frequent rethreading are avoided.

In the attainment of the objects above noted, a lockstitch shoe sewing machine of the type disclosed in the prior patents is provided with a shuttle, which is not stopped at the same time as the needle but which continues in operation until the other stitch-forming devices are brought to rest, the needle and loop spreader still being stopped at the upper extremity of their strokes, as in the prior machine. In so doing the shuttle is enabled to enter the final loop of thread carried through the work by the needle at the end of a seam and to complete the Patented Apr. 11, 196i formation of the last stitch during continued rotation of the shuttle after the needle is stopped. It is, therefore, unnecessary to take special precautions in severing the thread and unhooking it from the needle at the end of a seam, the thread being severed close to the surface of the work in-a manner corresponding to that employed in any other conventional form of hook needle lockstitch sewing machine. Such an arrangement has special advantages in a machine provided with a take-up for bringing each loop of needle thread down from the shuttle to the surface of the work after which the shuttle in forming the succeeding stitch acts to set the previously formed one. With such machine the point of interlocking engagement between the threads in'the last stitch of a seam is drawn closely to the upper surface of the work by the take-up, although a final stitch setting tension may or may not be applied according to adjustments. Under these circumstances a small loop of needle thread surrounding the locking thread may project above the upper surface of the work at a convenient location for engagement by a thread severing knife, so that a single slash of a knife will sever both the needle and the locking threads without wastage or thread damage.

In the machine of the prior patents a seam is normally completed with the next to the last stitch properly formed but not set in the work and with the last stitch partially formed only, the final needle loop not being interlocked with the locking thread. A further object of the present invention is to improve the operation of the prior machine, so that the next to last stitch will be set securely within the work and the needle and locking threads in the last stitch will be interlocked and drawn down to the surface of the work, so that they may be severed with a single slash of a knife. as above outlined. To these ends the machine is provided with a member actuated by a treadle for preventing the thread lock from closing only after the final needle loop of the last stitch of a seam is completed, so that as the take-up draws the final loop from the shuttle at the end of a seam thread mav be drawn from the supply of needle thread.

These and other features of the invention, as hereinafter described and claimed, including a new and improved form of thread end trimming knife on the horn and a new and improved form of shuttle driver, which enables the shuttle to be driven continuously a plurality of revolutions for each reciprocating stroke of the needle, will be apparent from the following detailed specification taken in connection with the accompanying drawings, in which Fig. 1 is a view in left side elevation of a lockstitch McKay shoe sewing machine embodying features of the present invention, parts having been broken away to show the underlying structure; a

Fig. 2 is a view in front elevation and on an enlarged scale of the head of the machine shown in Fig. 1, together with a portion of a shoe entering horn and with a section of work being operated upon as itappears at the end of a seam;

Fig. 3 is a detail view of the needle, shuttle, and horn, and a section of work being operated upon as it appears in the machine of the prior patents at the end of a seam;

Fig. 4 is a detail view in rear elevation of the upper portion of the machine showing a hand wheel and a brake member for assisting in bringing the machine to rest;

Fig. 5 is a sectional detail view in left side elevation of the driving connections for the shuttle in the machine;

Fig. 6 is a sectional detail view on an enlarged scale as seen from the line VI-VI of Fig. 5;

Fig. 7 is a detail view in front elevation showing take/up and thread lock of the machine; v

the

1 12g; 8 is a view in left side elevation of the thread Fig. 9 is a planview of athread lock disabling pawl in the machine;

Fig. 10 isa detail'planviewon an enlarged scale of the tip of a shoe supporting horn in the machine;

Fig. 11 is a perspective view of an improved thread trimming knife employed on the horn; I

Fig. 12 is a detail-view in front elevation and partly in section, illustrating the manner of operation of the thread trimming knife; and

Fig. 13 is a detail view on an enlarged scale showing the improved shuttle driver in the machine.

Except as hereinafter described, the machine illustrated in the drawings is the same asthat disclosed in the prior patents above referred to. g The principal characteristic of such machines is in the work support, which has the form of an angular and rotatably mounted shoe entering horn 2, best shown in Fig. 1. By reason of its shape and the limited dimensions at its tip, the horn is equipped with a needle threading looper or whirl 4 (Fig. 10), no thread finger being provided for supplying one side of each loop of needle threaded between a previously formed stitch in the work and the whirl as a straight hook needle 6 Withdraws its threaded hook from the work. For this reason, these machines have been constructed to operate with an overlapping stitch-forming cycle, in which thread is supplied for one side of each needle loop from g the previously formed stitch in the work, the previously formed stitch having been left loose with a surplus in an amount greater than that required as the threaded needle is withdrawn from the work. In other words, more than one rotation of the sewing shaft is required to form and set each stitch. To apply a stitch-setting tension to each previously formed stitch, the stitch-forming devices are timed to take up all of-the surplus as the loop in the succeeding stitch is being formed and is being carried about a discoidal shuttle 7 (Fig. 2) at the same side of the work as the needle.

As a convenient means of stopping the sewing operations, the machine of the prior patent is provided with driving and stopping mechanisms for driving a composite main sewing cam shaft, including a shaft indicated at 8 in the present drawings, and actuating connections between the sewing shaft and the needle and shuttle are arranged to be disconnected while the needle is at a position at. the upper end of its, stroke with a loop of needle thread held in its hook, as shown in Fig. 3 of the present drawings, the remaining stitch-forming and setting devices continuing their operations while connected to the sewing shaft until it comes to rest in an indeterminate position under the force of momentum in the parts. As a result, the second to .thelast stitch of a seam inserted by such machine is not set securely in the work and the last stitch is incompletely formed. Furthermore, it is necessary in the prior machine to unhook the last loop,

indicated at 10, of thread drawn through the work by the needle, carefully to avoid the possibility of damage to the thread and to insure that proper operationof the machine will be accomplished in starting a new seam. If the needle loop 10 is not first nnhooked from the needle both of its sides may be severed close to the surface of the work and the thread end remaining in the machine is withdrawn by the operator from the horn in an amount sufiicient to enable it to be laid in the needle hook with certainty in starting a new seam. Most operators, however, prefer the practice of severing one side only of the last-formed needle loop 10 close to the upper surface of the work and then unhooking that loop from the needle. Then, to avoidthe possibility that a stranded or damaged thread may be used in starting a new scam, the operator grasps the thread end remaining in the machine after stopping and withdraws a substantial lengths from the whirl 4. Such; withdrawal, besides Wasting thread, results'in the insertion ofthe first, stitch ina new seam with a substantial length dangling uselessly from the workg d which in the case of a shoe is concealed inside at a position where it is diflicult to trim.

The machine of the present invention avoids the difliculties above enumerated by inserting a seam, which is terminated with the second to the last stitch set securely within the work and with the last stitch completely formed and drawn down, a least to the surface of the work, and optionally also set securely within the work.

A comparison of Figs. 2 and 3 will disclose the advantages obtained by the use of the present machineover that of the prior machine. In Fig. 2 the last formed stitch in a seam sewn by the present machine is shown at 12, the needle loop for which is drawn with an interlocked section of locking thread 14 down to the upper surface of a piece of Work 16. From the loop 12 the needle thread, indicated at 18 runs from the last formed stitch 12 through two reversed right-angle bends into the tip of the horn 2. In order to release the work 16 from the machine, a workclarnping presser foot 20 which engages the upper surface is raised and the cutting edge of a hand held knifetnot shown) is moved along the upper surface of the work, severing both the needle and locking threads flush with that surface of the work, there remaining a short length of needle thread 18 projecting from the tip of the horn. In applying a new Work piece to the horn the thread is clamped between the work supporting surface of the horn tip and the undersurface of the work, the presser foot 20 applying sufficient pressure to the work to prevent escape of the needle thread end as the machine is started on a new seam.

Fig. 3 shows the positions in the prior machine of the locking thread and the ioop 16' of the needle thread supported by the needle hook and the loop spreader at the end of a seam. The locking thread runs from the shuttle to the second to last completely formed stitch 2 2 in the work. This stitch has not been set within the substance of the Work and the next to last loop of needle thread is, therefore, exposed above the upper surface of the work where it is drawn down with its interlocked section of locking thread nearly to the surface of the work. In removing the work from the machine, therefore, it is necessary to raise the presser foot, indicated at 24, to the position shown in Fig. 3 and then to sever the locking thread close to the work, preferably that side only of the needle loop 22 nearest the locking thread being severed. In removing the Work from the machine the remaining length of needle thread left in the loop 10 is released from the book of the needle which supports it and is withdrawn from the work. In releasing the needle thread from the needle hook it may become stranded on the hook so that suflicient attention must be given to avoid such damage. Even if the thread is undamaged a surplus length may be left extending from the tip of the horn, and when a new workpiece is applied to the horn an excessively long length will remain extending from the lower side of the work.

To eliminate an excessively long length of needle thread extending from a seam sewn in the prior machine a second trimming operation is required, which may not be convenient, especially if the work piece comprises the sole of a shoe with the long thread end extending inside the shoe where the space is relatively limited for proper manipulation of a trimming knife or for easy visibility.

The dilference in operation of the present and prior machines results primarily from a change in the driving and stopping mechanisms for the machine, wherein treadle controlled means is provided for disconnecting and for rendering only the needle inoperative after a loop of thread has been drawn through the work by the needle and before the needle starts its succeeding work penetrating stroke, rather than rendering both the needle and shuttle inoperative as in the prior machine. In the present machine the shuttle continues to rotate with the sewing shaft, the shuttle entering the final loop of thread retracted from the work by the needle and, thereafter drawing needle-thread from. the supply. through a; thread. lock 26 (see Fig. 8) for the completion of the last formed stitch 12. The sewing shaft also continues to rotate under the force of momentum while the shuttle enters the last formed needle loop. In entering the last formed needle loop the shuttle distends that loop and applies a stitch setting tension to the second to the last formed stitch in the work for this purpose.

The present shuttle 7 is similar to that employed in the prior machine and is of discoidal shape, the rear end of which is closed and the forward end of which is open to receive a cylindrical locking thread case 28 (Fig. 2) about which each loop of thread retracted from the work by the needle is carried by the shuttle. The front end of the locking thread case faces the needle toward which the locking thread is led as it is drawn into the work by an interlocked loop of needle thread. As in the machine of the prior patent, the present shuttle 7 has a loop entering beak 29, the path of movement of which is circular and defines a plane inclined to the needle to bring the beak, while in the lower portion of its path, closer to the needle than while in the upper portion of its path. The shuttle is formed within its beak with a throat recess 30 into which a driver 31 fits loosely to impart rotary movement to the shuttle while permitting each loop of needle thread to pass readily between the shuttle within its throat and the driver. The shuttle and looking thread case are to this extent the same as in the prior machine, except that the shuttle and thread case are of greater axial depth so that a substantially greater supply of locking thread may be contained in the thread case and a novel form of shuttle driver is employed.

In the prior patented machine the shuttle is actuated with an oscillating movement in each sewing cycle, first in one direction to enter each needle loop and then in the opposite direction to return it to its original position. The oscillating movement is imparted to the shuttle through connections with the mechanism for actuating the needle, so that when the needle of the prior machine is brought to rest in a position at the limit of its movement out of engagement wit-h the work, the shuttle also sops. A connection with the needle actuating mechanism also actuates the loop spreader and engages one side of each needle loop and holds it in an open position for entry of the shuttle. Thus, at the end of each seam, according to previous practice, the shuttle, loop spreader and needle hold the last loop of needle thread in the position of Fig. 3. This mechanism and its connections are driven from the main sewing shaft in a manner more fully disclosed in the prior patents above referred to.

Briefly, the mechanism for actuating the present needle 6 includes a vertically reciprocating bar 32 to the lower end of which the needle 6 is secured, a block 33 (see Fig. 2) rigidly clamped to the needle bar 32, and a link 34 pivotally connected at its ends to the block 33 and to a needle lever 36 secured to the forward end of a rock shaft 38 rotatable in the machine frame. Loosely sleeved on the rock shaft 38 beside the needle lever 36 is an actuating lever 40 continuously oscillated by the shaft 8 and arranged to be connected to or disconnected from the needle lever 36. The actuating lever 40 has a cam groove 42 engaged with a crank pin 44 offset from the forward end of the shaft 8.

For actuating the needle lever 36 from the lever 40 a disconnectible connection is provided in the needle actuating mechanism between these two levers comprising a latch 46 pivotally mounted on a pin 48 at the left end of the needle lever 36. At the lower end of the latch 46 is a hooked portion for engagement with a pin 50 secured to an adjacent end of the actuating lever 40. When the latch 46 engages the pin 50 the two levers 36 and 40 move together as a unit. When disconnected, as illustrated in Fig. 2 of the present drawings, the needle lever 36 is locked out of operation at the upper end .of the reciprocating stroke for the needle. For this purpose the pin 48 engages a slot 52 in a locking lever '54,

the slot 52 in the locking lever is offset to the right, so-

that for the ucpermost position of the needle lever it will be held out of operation. At the upper end of the locking lever is an abutment 58 acting on an upwardly extending arm of the latch 46 to disconnect the latch from the pin 50 when the horizontal portion of the slot 52 engages the pin 48. For actuating the locking lever 54 the shaft 56 to which it is secured is provided at its rearward end with an integral lever arm 60. The lever arm 60 is connected by a short link 62 with one end of a control lever 64 (see also Fig. 1) loosely mounted on a pivot shaft 66 rotatable in the frame of the machine.

To urge the latch 46 (Fig. 2) into engagement with the pin 50, the pin 48 on which the latch is mounted has coiled about it a spring 68 (see Fig. l) acting on the latch. To shift the latch 46 against the force of its spring 68 away from the pin 50 and the actuating lever 40, the pivot shaft 66 has at one end a spring 69 (Fig. 4) engaging at one end a lug on the machine frame and connected at the other end with the shaft. At the other end of the shaft 66 is a second spring 70 secured at one end to the shaft and at the other end to the arm 64, the force of the spring 70 being greater than that of the latch spring 68.

The treadle controlled means for the driving and stopping meohanisms includes an arm 72 projecting from and secured to the pivot shaft 66 and having a lug located beneath a rearward extension of the control lever 64. The arm 72 is pivotally connected to the upper end of a rod 74 extending downwardly to a driving and stopping treadle '76 mounted in the base of the machine frame. Also, within the base is a driving motor 78 connected through a friction clutch 80 controlled by the treadle 76 with a countershaft 82 carrying a bevel gear 84 meshing with a similar gear 86 on the lower end of a vertical driving shaft 88 comprising a second part of the composite sewing shaft, the upper end of which shaft 88 is similarly connected through bevel gears 90 and 92 with the shaft 8. By reason of the clutch 80 the driving motor 78 is disconnected from the vertical shaft 88v and the shaft 8, when the treadle 76 is permitted to rise under the force of the spring 69 and a spring 94 stretched between the arm 72 and a pin 95 in the sewing head frame, the springs 69 and 94 being of suflicient strength to overcome the coil spring 70. When the treadle 76 is depressed by the operator the lug on the treadle connected arm 72 moves the control lever 64 so that the control lever rotates in a counterclockwise direction, as shown in Fig. 1. Such counterclockwise rotation of the control lever 64 causes the locking lever to unlock the needle lever 36 and to move the latch 46 into engagement with the pin 50 on the actuating lever 40. Continued depression of the treadle 76 engages the clutch 80 and drives the shaft 8. When the treadle is released the control lever 64 is first operated, the shuttle, take-up and stitch-forming devices other than the needle continuing to operate under the influence of momentum.

In place of the oscillating shuttle of the prior patent the present shuttle 7 is driven by its driver 31 continuously in the same direction through bevel gears 96 and 98 on the vertical shaft 88 and an inclined shaft 106. The gear 98 has an elongated hollow hub rotating in a split bearing 102 on the machine frame and a radially grooved enlargement at its forward. end engaging with a co-operating rib on the collar 104 keyed but free to slide on an inclined second shaft 106, the shaft 106 being loose within the hub of the gear 98. The forward end of the inclined shaft 106 is connected to a universal joint 108, in turn connected to an alined shaft to the forward end of which the shuttle driver 31 is secured. The ribbed 'collar 104 and the grooves of the enlargement 100 form a slip connection between the inclined shaft 106 and the gear 98 which drives it. The universal joint 108 assists in reducing vibration in the shuttle driving connections and contributes to a smooth running machine.

I worth.

To take out the lost motion between the shuttle driv-- ing parts and the universal joint the ribbed collar 104 and the enlargement 100 are pressed axially together by ;a1- single spring 112 of the coil compression type mounted;

onthe shaft 106 and compressed between checknuts 114 thereon and the collar 104. The spring 112 therefore prevents displacement of the rib on the collar 104 from the groove on the enlargement 100, except when the shuttle becomes jammed by thread or other extraneous substance.

The gears 96 and 98 are constructed to rotate the shuttle 7 twice for each complete reciprocation of the needle 6. By reason of the inclined plane of the shuttle the locking thread 14, as it is led from the thread case 28 passes into close proximity to the path of the shuttle beak 29 (see Fig. 13).

To deflect the locking thread leading from the thread case 28 away from the shuttle beak 29, so that the locking thread will not be impaled and stranded by the shuttle beak, the shuttle driver 310f the illustrated machine projects through the throat recess 30 of the shuttle beyond its plane at the side facing the needle. The projecting corners and the edges of the driver are smoothly rounded to prevent thread abrasion. Thus, when the beak of the shuttle passes the locking thread 14 an abrupt bend 116 (Fig. 13) is produced and the locking thread is urged forwardly sufiiciently to prevent stranding by the shuttle beak when in the lower portion of its path. Also, the deflection of the locking thread by the driver 31 serves to withdraw a short length of locking thread from the thread case for the completion of the stitch being formed at that time. In this way, the locking thread may be drawn into the work more readily and each stitch is set more accurately beneath the surface of the work. Withdrawing locking thread in this manner is particularly beneficial when it is desired to terminate each seam with a stitch drawn down and set below the surface of the work.

The stitch-forming devices of the machine include, in addition to those already named, a loop spreader 117 (see Fig. 2), a thread tension 118 (Fig. 1), and a takeup 12G (Fig. 7) constructed and operated in substantially the same manner as in the prior patents above referred to. It may be noted, however, that the thread tension in the present machine is mounted on a bracket 122 secured to a needle thread supply container 124 rather than upon a wax pot supporting bracket as in the prior machine,

the wax pot in the illustrated machine being indicated,

The thread lock 26 against which each stitch is set by the action of the shuttle is generally similar to that disclosed in United States Letters Patent No. 1,983,161, granted December 4, 1934, upon application of Fred Ash- The thread lock 26 is in the form of a shoe pivotally mounted on one arm ofa lever 128 having an integral stud rotatably mounted in a bearing 130 of a bracket 132 secured to a cover 134 for the waxpot 126.

The cover 134 is attached by bolts 136 in a conventional manner to the frame of the machine, as in the prior patent. The thread lock 26 acts to grip the threadagainst a plate 138 secured to the bracket 132 and is actuated by an arm 1% (see Fig. 7) carrying a roll 142 engaging a cam plate 144 adjustably secured to a gear 146 attthe forward end of a horizontal shaft 148 comprising a third part of the composite sewing shaft, said shaft 148 being rotatably mounted in the main frame and connected to the vertical shaft 88 through beveled gears 150 and 152 (Fig. 1) on the shafts 148 and 88, respectively.- The gear 14-6 also carries an eccentric crank pin 154 for actuating V the take-up 120, as in the prior patent..-

To cause the thread lock to grip the thread and lock it against movement from the supply, the horizontal arm of the lever 128 carries an adjusting screw 155 (Fig. 8)

engaging at its lower end with a button 156 forming a.

seat for a compression spring supported by a pin 157 on the wax pot cover 134. During normal sewing operationsthecam plate .144. causes the thread lock to clcse -before;- each needle. loop .is being pulled from the shuttle-by the;take- -up. When;.the needle loop is pulledby the-take-up; to a predetermined position, shown in Fig, 2,- downwardly toward the upper surface of the work, thethread lock is opened and remains open until after the whirl 4 starts to lay a new loop of thread in the hook of the needle 6., The. needle then retracts from the work, drawing with it suflicient thread from the previous loop for one side of the new needle loop and as this latter ioop is spread and passed about the shuttle, the previously formed needle loop is in turn drawn yieldingly down to the surface of the work against the resistance offeredby the thread tension 118, the thread being drawn thereafter by the shuttle from the supply for the formation of the next stitch. While the thread is being drawn from the supplyfor the next stitch, the previously formed loop of needle thread rests on the upper surface of the work and, as the succeeding needle loop on the shuttle its driving means and the needle, at the upper end of its stroke, to be disconnected from its actuating lever 36, rendering the needle inoperative after the final loop of thread carried by its hook has been drawn through the work. As the needle approaches the upper end of its stroke, the final loop of thread carried thereby is opened up by the loop spreader into position where it may be entered by the beak of the shuttle, which is continuing its rotation under the force of momentum exerted by the rotating, driving andsewing shafts. -The shuttle, therefore, disengages the final loop from the needle and loop spreader and sets the previously formed or second to the last stitch at a uniform depth within the work. The take-up also continues in its operation to draw the final needle loop of the last formed stitch 12 down to a position close to the upper surface of the. work, as illustrated in Fig. 2, and eventually the main sewing shaft parts come to rest.

When the composite main sewing shaft 8, 88, and 148 comes to rest at the end of aseam inserted by the machine, the positions of the needle and locking threads Hand 18 remain as in Fig. 2 where both may be severed with a single slash of a hand held knife, so that the work 16 may readily be removedfrom the machine without drawing thread with it. When the work is removed the end of the needle thread 18 is withdrawn from the last formed perforation in the work and lies across the work supporting surface of the horn 2 with a sufficient length to insure proper starting of a new seam.

If the machine is allowed to remain at rest for any substantial length of time after stopping, the end of a waxed needle thread lying across the tip, of the horn has an opportunity to harden. It is, therefore, common for an operator to withdraw manually sufiicient freshly waxed thread from the horn tip before starting a new seam to insure that the wax will be in soft, pliable condition. For this purpose it is necessary for the thread lock 26 to be opened whenever the machine is brought to rest.

To enable thread to be withdrawn freely from the horn at the end of a seam, the thread lock lever 128 has a third horizontal arm having 2. lug 159 arranged to be engaged by a vertical detent 160 secured to a horizontal shaft'162 rotatably mounted in a bearing plate 164 on thewax pot cover 134 and connected for direct actuation to the treadle. The shaft 162also has secured to it a horizontal arm 166 provided with openings to receive a pin 16? (Fig. hanng extending;throughatransverse eye at one of its ends, a rod 168 extending downwardly to a pivotal connection with the treadle 76. Surrounding the upper end of the rod 168 is a coil spring 170 (see Fig. 7), the lower end of which engages a flattened surface on the pin 167. Beneath the pin the rod 168 has clamped to it a collar 172, which when the treadle 76 rises engages the pin 167 and moves the detent 160 beneath the lug 159 on the third arm of the thread lock lever 128. This occurs only after the thread lock has been opened by the cam plate 144. During sewing operations a head on the rod 16% engages the upper end of the spring 179 and holds the detent out of the path of the lug 159 on the thread lock lever 128. As the treadle is released at the end of a scam the needle is first disconnected and then the detent 161) is moved toward the lug 159 on the lock lever 128.

In order to enable the thread lock 26 to be operated in the usual way until after the last stitch 12 of a seam has been drawn down to the upper surface of the work by the take-up, as shown in Fig. 2, means is provided for retarding the upward movement of the treadle and for preventing the engagement of the detent 160 with the lug 159 before the take-up has time to draw the final loop of needle thread from the shuttle against the action of the thread lock. The treadle retarding means consists of a bar 174 pivotally connected at its lower end to the treadle 76 and secured at its upper end to a cylinder 176 of a dash pot. Inside the cylinder 176 is a piston 178 connected to a rod 180, which, in turn, is pivotally connected by a screw 182 to the machine frame. In stopping the machine the dash pot 176, 178, thus, enables the sewing shaft to rotate through several revolutions after the take-up draws the last formed stitch 12 to a position close to the upper surface of the work while the lock closes in the usual way and then after the detent is allowed to move toward the lock lever the lock is opened and retained in open position for convenience in thread withdrawal.

To reduce the time required for stopping the composite main sewing shaft 8, 88 and 148 after the treadle is released and moved upwardly, the gear 90 on the driving shaft 88 has meshing with it a bevel gear 184 secured to a stub shaft 186 passing through bearings in the side walls of the sewing head frame of the machine. At the left outer end of the stub shaft 186 is a hand wheel 188 having an integral flange 190 (see Figs. 2 and 4) with which is engaged a friction brake block 192. The brake block 192 is secured to a downwardly and laterally projecting portion of the arm 72. The brake block 192 is brought into engagement with the flange 190 of the hand wheel when the rearward end of the arm 72 (Fig. 1) is raised fully by the tension spring 94. To facilitate the rising movement of the arm 72, the treadle 76 is acted upon by a spring 196 stretched between the treadle and the machine frame. The arrangement is such that during the delayed rise of the treadle 76 the brake block eventually engages the flange 190, quickly stopping the sewing shaft rotation. This occurs after the needle has been disconnected from the main sewing shaft 8, 88 and 148. The spring 194 also assists in moving the locking lever 54 to lock the needle lever 36 when the treadle is released, the springs 194 and 94 exerting a greater force through the connection than that of the spring 70.

To enable the initial portion of the needle thread withdrawn from the horn 2 by the operator to be trimmed in close proximity to the under surface of the work with a minimum of effort, the horn of the illustrated machine is provided at its tip with a trimming knife which is particularly well adapted for the purpose and is arranged to prevent damage to the work when in the form of a shoe or similar hollow article. The illustrated horn 2 is constructed similarly to that disclosed in United States Letters Patent No. 1,931,917, granted October 24, 1933, upon application of Fred Ashworth. The horn has a removable frame 198, best shown in Figs. and 12.

The frame 198 has a bearing at its extremity for the whirl 4. Above the whirl is a cap 24111 having a needle receiving aperture 202 secured to the frame 198 by a screw 204. To assist in securing the cap to the frame the shank of the cap is closely confined within a slot 286 in the frame and at one side where it emerges from the slot the cap has an undercut shoulder 2118 engaging a corresponding shoulder on the frame 198.

The thread end trimming knife indicated at 210, is constructed in L-shaped' form having a sharpened edge 212 at its upper extremity and a right-angle tongue 214 on its base for securement between the attaching tongue of the cap 208 and the frame 198 of the horn, the upper extremity fitting within a clearance space within the slot 206 between the cap and the frame. For protecting the cutting edge of the knife from improper or damaging action to the work piece, the edge 2-12 is disposed within a recess 216 in the side of the cap 200 opposite the shoulder 208.

In operation the trimming knife engages the initial end of the needle thread, indicated at 218, withdrawn from the horn in starting a new seam. For this purpose the thread end 218 is held within the grasp of the operators hand, as illustrated in Fig. 12, the horn being oriented about its rotary axis to a position in which the work is fed toward the cutting edge of the knife, so that as the seam inserted by the machine progresses, the thread end 218 will be carried into the recess 2.16 and against the cutting edge 212. Thus, it is evident that after the formation of two or three stitches, illustrated by cross marks 220, the thread will be severed close to the first stitch, as in Fig. 10.

Certain features of the invention herein disclosed form the subject matter of divisional applications as follows: Serial No. 856,955, filed December 3, 1959, relating to thread trimming devices for lock stitch shoe sewing machines, and Serial No. 861,669, filed December 23, 1959, relating to improved shuttle driving mechanisms for such machines.

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

1. A lockstitch shoe sewing machine having a rotatably mounted shoe-entering horn, stitch-forming and setting devices including a hook needle, a take-up for drawing each loop of needle thread partially down to the surface of the work on the horn to leave sufficient thread for one side of the needle loop during the formation of the next succeeding stitch, a shuttle acting to draw. 0E thread from the supply for the next stitch and thereafter to set the previously formed stitch, a thread lock against which the stitch is set, a sewing shaft for actuating the stitch-forming and setting devices and for closing the thread lock at a predetermined point in the movement of the shuttle, and means for driving the sewing shaft, in-

combination with treadle controlled means for disconnecting the sewing shaft from its. driving means and for rendering the needle inoperative after a loop of thread has been drawn through the work by the needle and before the needle starts its succeeding Work penetrating stroke while the shuttle enters the final loop of thread retracted from the work by the needle and draws thread from the supply through the thread lock for the completion of the last formed stitch, the sewing shaft continuing to rotate after being disconnected from its driving means.

2. A lockstitch shoe sewing machine having a rotatably mounted shoe entering horn, stitch-forming and set ting devices, including a hook needle, a looper, a take-up for drawing each loop of needle thread partially down to the surface of the work while leaving sufiicient thread for one side of the needle loop during the formation of the next succeeding stitch, a locking thread case, a shuttle acting to draw'otf thread'from the supply for the next stitch and thereafter to set the previously formed stitch,

1 l a thread lock against which the-stitch is set, a main sewing shaft, suitable connections between the sewing shaft and the stitch-forming devices for actuating them in timed relationship to close the thread lock at a predetermined point in the movement of the shuttle, and means for driving the sewing shaft, in combination with means including treadle controlled driving and stopping mechanisms for disconnecting the sewing shaft from its driving means to enable the stitch-forming devices to be brought to rest while connected to the sewing shaft and for rendering inoperative those actuating connections between the sewing shaft and the needle after the looper has laid a loop of thread in the needle hook and before the needle starts its succeeding Work penetrating stroke to enable the final loop of thread retracted from the work by the needle to be carried about the locking thread case by the shuttle and to be drawn from the shuttle toward the work by the take-up.

3. A lockstitch shoe sewing machine having stitchforming devices including a hook needle, a main sewing shaft, suitable connections between the sewing shaft and the stitch-forming devices for actuating them in timed relationship, including an actuating lever continuously oscillated from the sewing shaft, a needle lever, a latch for connecting said levers, means including a locking lever movable to disengage the latch and lock the needle lever in a position with the needle out of engagement with the work, means including a yieldingly actuated control lever connected to the locking lever for urging it into unlatching position, a pivot for said control lever, and means including an arm rotatably mounted on said pivot and arranged to actuate the control lever against its yielding force, in combination with means including a brake on said arm for stopping the main sewing shaft after the latch disconnects the actuating lever from the needle lever.

4. A lockstltch shoe sewing machine having a rotatably mounted shoe entering horn, stitch-forming and setting devices, including a hook needle, a looper, a take-up for drawing each loop of needle thread partially down to the surface of the work while leaving sufiicient thread for one side of the needle loop during the formation of the next succeeding stitch, a locking thread case, a shuttle acting to draw off thread from the supply for the next stitch and thereafter to set the previously formed stitch, a thread lock against which the stitch is set, a main sewing shaft, suitable connections between the sewing shaft and the stitch-forming devices for actuating them in timed relationship to close the thread lock at a predetermined point in the movement of the shuttle, and means for driving the sewing shaft, in combination with means-including treadle controlled driving and stopping mechanisms for disconnecting the sewing shaft from its driving means to enable the stitch-forming devices to be brought to rest while-connected to the sewing shaft and for rendering inoperative those actuating connections only between the sewing shaft and the needle after the looper has laid a loop of thread in the needle hook and before the needle starts its succeeding work penetrating stroke to enable the final loop of thread retracted from the work by the needle to be carried about the locking thread case by the shuttle and to be drawn from the shuttle toward the work by the takeup, and means connected for direct actuation to the tread-le for preventing the thread lock from closing after the needle is disconnected from the sewing shaft.

5. A lookstitch shoe sewing machine having a rotatably mounted shoe entering horn, stitch-forming and setting devices, including a hook needle, a looper, a take-up for drawing each loop of needle thread partially down to the surface of the work while leaving sufficient thread for one side of the needle loop during the formation of the next succeeding stitch, a locking thread case, a shuttle acting to draw ofif thread from the supply for the next stitch and thereafter to set the previously formed stitch, a thread lockagainstwhich the. stitch is set, a main sewing shaft,

, l2 suitable connections between the sewing shaft and the stitch-forming devices for actuating them in timed relationship to close the thread lock at a predetermined point in the movement of the shuttle, and means for driving the sewing shaft, in combination with means including treadle controlled driving and stopping mechanisms for disconnecting the sewing shaft from its driving means to take-up, means including a treadle controlled member for preventing the thread lock from closing after the needle is disconnected from the sewing shaft, and means for retarding the action of the thread lock closing preventing member before the take-up draws the final loop of needle thread from the shuttle.

6. A lockstitch shoe sewing machine having a rotatably mounted shoe entering horn, stitch-forming and setting devices, including a hook needle, a looper, a take-up for drawing each loop of needle thread partially down to the surface of the work while leaving sufiicient thread for one side of the needle loop during the formation of the next succeeding stitch, a locking thread case, a shuttle acting to draw off thread from the supply for the next stitch and thereafter to set the previously formed stitch, a thread lock against which the stitch is set, a main sewing shaft, suitable connections between the sewing shaft and the stitch-forming devices for actuating them in timed relationship to close the thread lock at a predetermined point in the movement of the shuttle, means for driving the sewing shalt, driving and stopping mechanisms for disconmeeting the sewing shaft from its driving means to enable the stitch-forming devices to be brought to rest while connected to the sewing shaft and for rendering inoperative the actuating connections between the sewing shaft and the needle after the looper has laid a loop of thread in the needle hook, and means including a treadle for controlling the driving and stopping mechanisms, in combination with means including a detent connected for direct actuation to the treadle for preventing the thread lock from closing after the needle is disconnected from the sewing shait.

7. A lockstitch shoe sewing machine having-a rotatably mounted shoe entering horn, stitch-forming and setting devices, including a hook needle, a looper, a take-up for drawing each loop of needle thread partially down to the surface of the work while leaving sufficient thread for one side of the needle loop during the formation of the next succeeding stitch, a locking thread case, a shuttle acting to draw oif thread from the supply for the next stitch and thereafter to set the previously formed stitch, a thread lock against which the stitch is set, a main sewing shaft, suitable connections between the sewing shaft and the stitch-forming devices for actuating them in timed relationshipto close the thread lock at a predetermined point in the movement of the shuttle, means for driving the sewing shaft, driving and stopping mechanisms for disconnecting the sewing shaft from its driving means to enable the stitch-forming devices to be brought to rest while connected to the sewing shaft and for rendering inoperative the actuating connections between the sewing shaft and the needle after the looper has laid a loop of thread in the needle hook, and a treadle forcontrolling the driving and stopping mechanisms, in combination with means including a detent connected to the treadle for preventing the thread lock from closing after the needle is disconnected from the sewing shaft, and dash pot means for retarding the movement of the treadle to delay the action 13 14 of the detent toward thread lock closure preventing po- 1,885,927 Leveque Nov. 1, 1932 sition. 2,158,484 Poole May 16, 1939 2,209,455 Haas July 30, 1940 References Clted 1n the file of thxs patent 2,283,073 Leveque May 12, 1942 UNITED STATES PATENTS 5 2,352,708 Haas July 4, 1944 1,482,619 Reed Feb. 5, 1924 2,376,648 Anderson May 22, 1945 1,519,652 Ashworth Dec. 16, 1924 1,528,719 Windham Mar. 3, 1925 FOREIGN PATENTS 1,547,567 Dye July 28, 1925 535,239 Great Britain Apr. 2, 1941 1,833,366 Leveque Nov. 24, 1931 10

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