US1200555A - Wax-thread sewing-machine. - Google Patents

Description

P. J. WENTWORTH.

WAX THREAD SEWING MACHINE.

APPLICATION FILED DEC. 5, 1912.

2 SHEETS-SHEET l.

P. J. WENTWORTH.

WAX THREAD SEWING MACHINE.

APPLICATION FILED DEC. 5, 1912. 1 1,200,555. Patented 10110,1916.

2 SHEETS-SHEET 2- m: nouns PETERS ca. FHOTOJJIWQ. WASNING row. a. c.

srnrns PATENT anion.

PEARL J. WENTWOBTH, OF MATTAPAN, MASSACHUSETTS, ASSIGNOR T0 UNITED SHOE MACHINERY COMPANY, OF PATERSON, NEW JERSEY, A CORPORATION OF NEW JERSEY.

WAX-THREAD SEWING-MACHINE.

Specification of Letters Patent.

Patented Oct. 1o. 191a.

To all whom it may concern:

Be it known that I, PEARL J. VVENTWORTH, a citizen of the United States, residing at Mattapan, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Wax- Thread Sewinglfachines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to sewing machines and more particularly to machines for sewing a seam with wax thread.

In the process of sewing a shoe or other piece of work on a wax thread machine, the operator in removing the work from the machine usually draws 05 more or less thread from the supply and cuts off the thread close to the work. This provides a length of thread extending from the thread handling devices in excess of the amount required to reach to the work and to form the first stitch of the next seam. This excess of thread is essential in order to enable the first stitch to be formed and tightened in a certain and reliable manner. In a lock stitch machine the needle thread and in a chain stitch ma chine the single thread must be grasped by the operator or held in some other manner during the formation of the first stitch of the seam. In a lock stitch machine the free end of the shuttle thread must be long enough to insure the catching of the shuttle thread my the needle thread when the loop of needle thread is drawn down into the work. In any case the first stitch is formed at some distance from the end of the thread and the free end of thread is left projecting from the work at the beginning of the seam. This free end of thread is usually cut off by the operator by means of a hand knife when the seam is finished and this operation necessarily consumes considerable time. When light colored stock is being sewn the free end of the thread, if it is not cut ofi until the completion of the seam, is liable to soil the workby contact therewith during the sewing operation.

The primary objects of the present lnvention are to provide a wax thread sewing machine with means whereby the free end of the thread at the beginning of the seam is severed close to the work in a certain and reliable manner without waste of time and with very little care, skill or effort on the part of the operator.

WVith these objects in view the invention comprises various novel and advantageous features clearly set forth in the following description and pointed out in the claims appended thereto.

In the accompanying drawings illustrating the invention in its preferred form, Fig ure 1 is a front elevation of a portion of a sewing machine embodying the invention; Fig. 2 is a plan view of a portion of the mechanism illustrated in Fig. 1, showing particularly the presser foot, the work sup port, and the parts adjacent thereto; Fig. 3 is a plan view of the work support detached from the machine; and Fig. el is a similar view of the presser foot.

The sewing machine illustrated in the drawings is a lock stitch, wax thread machine for sewing the outsoles to the uppers of boots and shoes, and in general the parts of the machine are the same in construction arrangement and mode of operation as the corresponding parts in the machine illustrated in the patent to French and Meyer, No. 173,870, dated April 26, 1892. The stitch forming devices of the machine comprise a curved hook needle indicated at 1, a looper 2 for laying the lower thread indicated at f about the needle, a thread finger 5, and a rotary shuttle 6 containing the upper or look ing thread indicated at 7. The work is supported by a work support 8 and a presser foot 9 cooperates with the work support to holdthe work in position during the formation of the stitches. The work is fed by the lateral movement of a curved awl 10 while the awl is in engagement with the work. The awl is secured to an awl segment 11 which is mounted to oscillate upon the upper end of an upright 12 secured to the feed slide 13. The feed slide is reciprocated to feed the work by means of an oscillatory lever 14, the forwardly extending arm of which is provided with an arc shaped groove to receive a roll 15 mounted on the feed changing lever 16 pivoted to the feed slide. The lever 1a is provided with a roll 17 which engages a cam groove 18 in a cam disk 19 secured to the cam shaft of the machine, not shown.

When the seam about the sole of the shoe has been completed, the operator lifts the presser foot from the machine and removes the work from between the presser foot and the work support. As the operator removes the work from the machine he draws off more or less of both the upper and lower threads from the respective sources of thread supply, and cuts both threads close to the work. This provides lengths of both upper and lower threads in excess of the amount required to reach to the work and to form the first stitch. The excess in the length of the upper thread insures the catching of the upper thread in the loop of the lower thread as the lower thread after passing about the shuttle is pulled down into the work by the takeup. The excess in the length of the lower thread enables the end of the lower thread to be held during the formation of the first stitch. The first stitch is formed at. some distance from the free ends of the threads and in the present invention, provision is made for cutting off the projecting free ends of both the upper and lower threads close to the work. To this end cutting devices are provided for cutting both the upper and lower threads, and in the illustrated embodiment of the invention these cutting devices are arranged so that the threads when held at a point relatively remote from the sewing point in a manner hereinafter explained are carried against the cutting edges of the cutting devices to sever the thread by the feed move ment of the shoe during the sewing opera tion. The cutting device for the upper thread consists of a knife indicated at 20 secured to or formed integral with the presser foot. The knife 20 is made in the form of a hook which extends in advance of the sewing point and across the line of the seam, as shown in Fig. 2. The cutting device for the lower thread consists of a hook shaped knife 21 mounted upon the work support in advance of the sewing point. The work support is cut away in front to provide a recess in advance of the knife to receive the thread as shown in Fig. 3. In order to enable the knife to yield rearwardly when its hooked end comes in contact with the edge of the toe cap or any other abrupt surface on'the shoe, so that it will not injure the shoe, the knife is formed on a dovetail slide 22 which is mounted in a dove-tail groove in the work support. The knife slide is yieldingly pressed forward by means of a spring 24 which engages its rear edge. The undercut portion ofthe right-hand side of the groove in the work support (Fig. 3) is terminated short of the forward portion of the foot so as to form a stop 23 to engage the knife slide and limit the forward movement thereof.

Before the work is inserted in the machine the end of the lower thread which extends up through the slot in the work support is grasped by the operator and drawn along the front of the work support until it drops into the recess'in front of the knife 21. At the beginning of the sewing of a scam the shoe is presented to the machine with the sole and welt between the presser foot and work support, and the operator grasps the end of the thread 7 in his left hand while still holding the shoe, and holds this thread fairly taut in advance of and slightly back of the sewing point. The lower thread, after having been inserted in front of the thread cutting knife 21, as stated above, may be held in the left hand of the operator, or the end of this thread may be held in any suitable gripping device attached to the machine. In the illustrated embodiment of the invention the end of the thread is held by a gripping device consisting of a spring plate 26 secured to the shank of the work support, the thread being gripped between the spring plate and the adjacent face of the work support shank. The lower thread may be inserted beneath the spring plate 26 at the time when it is drawn in front of the cutting knife 21. Upon starting the machine the needle advances through the work, receives the lower thread from the looper, draws the loop of lower thread through the work, which loop is then caught by the hook of and passed about the shuttle, after which the takeup acts'to tighten the stitch, drawing the lock between the upper and lower threads down into the work. During this operation the upper thread is drawn down in front of the upper thread cutting hook or knife 20, as shown in Figs. 1 and 2. After the first stitch is formed, both the upper and lower threads lie in front of the hook shaped cutting knives 20 and 21 respectively, and when the work is fed both threads are drawn toward the cutting edges of the knives. The upper thread 7 being held in the hand of the operator is held taut and carried along with the shoe as the shoe is fed. The lower thread, whether held in the hand of the operator or beneath the spring plate 26, is kept taut by the action of the takeup. hen the work has been fed a suflicient amount, the pull of the upper and lower threads against the edges of the cutting knives will cause the severing of the threads close to the work. In a machine constructed as illustrated in the draw ings, the threads will be severed during the feed movement of the work subsequent to the formation of the second stitch of the seam.

By means of the above described cutting devices the projecting free ends of the threads are cut close to the work at the beginning of the seam in a reliable and eflicient manner without loss of time, and with very little skill or effort on the part of the operator. Since the free end of the thread is severed at the beginning of the sewing operation the soiling of the work by the contact of the free end of the thread therewith during the sewing operation is obviated.

Having explained the nature and object of the invention, and having described a ma-' chine in which the invention may be embodied, what is claimed is 1. A sewing machine, having in combination, stitch forming devices, constructed and arranged to form a linearly extending series of stitches, work feeding means, and a thread cutting device arranged to sever close to the work during the first part of the seam formation and after one or more stitches have been set in the work, the free end of the thread projecting from the work at the beginning of the seam.

2. A sewing machine, having in combination, stitch forming devices constructed and arranged to form a two thread seam and thread cutting devices arranged to sever close to the work during the first part of the seam formation the free ends of both the upper and under threads projecting from the work at the beginning of the seam.

3. A sewing machine, having in combination, stitch forming devices constructed and arranged to form a linearly extending series of stitches, work feeding means, a thread gripping device for gripping and holding the free end of the thread during the first part of the seam formation and a thread severing device constructed and arranged to sever between the gripping device and the work during the first part of the seam formation and after one or more stitches have been set in the work, the free end of the thread projecting from the work at the beginning of the seam.

4. A sewing machine, having in combination, stitch forming devices, Work feeding means, and a thread cutting knife mounted on the thread supply side of the work and close to the sewing point in position for the free end of the thread projecting from the work at the beginning of the seam to be drawn against the knife by the feed movement of the work during the first part of the seam formation for severing close to the work the free end of the thread.

5. A sewing machine, having, in combination, stitch forming devices, feeding means, means for supporting the work and a thread cutting knife mounted on the work supporting means for yielding movement in a direction away from the work when engaged by the work.

6. A sewing machine, having in combination, stitch forming devices constructed and arranged to form a two thread seam, work feeding means, a work support, a presser foot and two thread cutting knives mounted respectively on the work support and presser foot and arranged to sever close to the work during the first part of the seam formation, the free ends of the upper and under threads projecting from the work at the beginning of the seam.

7 A sewing machine, having in combination, stitch forming devices constructed and arranged to form a two thread seam, work feeding means, a work support, a presser foot, two thread cutting knives mounted respectively on the work support and presser foot and arranged to sever close to the work during the first part of the seam formation the free ends of both the upper and under threads pro ecting from the work at the beginning of the seam and a thread gripping device for gripping one of the threads while the thread is severed between the gripping device and the work by one of the knives.

PEARL J. WENTWORTH.

Witnesses:

OHA NOEY M. SINGERBEAUX, BURTON W. CARY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. O.

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