US2194897A

US2194897A - Shoe sewing machine

Info

Publication number: US2194897A
Application number: US200413A
Authority: US
Inventors: Otto R Haas
Original assignee: United Shoe Machinery Corp
Current assignee: United Shoe Machinery Corp
Priority date: 1936-04-29
Filing date: 1938-04-06
Publication date: 1940-03-26
Anticipated expiration: 1957-03-26
Also published as: GB493628A; US2148197A; US2188683A; US2239603A; US2175056A; DE659372C; US2205383A; US2257950A; US2173299A; FR821227A; US2226401A; US2201969A

Description

O. R. HAAS SHOE SEWING MACHINE Original Filed April 29, 1936 2 Sheets-Sheet l (Ittornegs March 26,1940.

0. R. HAAS ,8 7

. SHOE SEWING MACHINE Original Filed April 29, 1936 2 Sheet s-Sheet 2 (Ittornegs Patented Mar. 26, 1940 UNITED STATES snon SEWING MACHINE Otto R. Haas, North Beverly, Mass., assignor to United Shoe Machinery Corporation, Borough of Flemington, N. J., a corporation of New J ersey Original application April 29, 1936,'S erial No. 76,924. Divided and this application April 6,

1938, Serial No. 200,413

4 Claims.

The present invention relates to sewing machines, and more particularly to improvements in thread tensioning mechanism therefor. The illustrative embodiment of the invention is similar 5 to that disclosed in inventors pending application Serial No. 76,924, the present application being a divisionof said case.

There is frequently employed in sewing machines, particularly those of the lockstitch type, auxiliary thread tensioning mechanism adapted to act upon the thread between the take-up and the looper to aid in the performance of the looping operation. I devices are, however, subject to the disadvantage that the operation of re-threading the machine is rendered more difiic'ult and the time required for such operation thereforeincreased.

As a general rule, the thread handling mechanisms of sewing machines are enclosed, not only to protect the o-peratorfrom injury but also, in the case of wax thread sewing machines, to provide a heat-retainingenclosure for the'thread in its passage from the wax pot through the take-up and auxiliary tensioning devices to the looper.

In order to provide access to the enclosed devices to permit re-threading of a new thread supply, and for purposes of repair or adjustment of the parts, removable covers are employed. It has been found that the operator, upon completion of the threading operation or the like, is apt to fail to close or replace the cover, with the result that the machine isthen operated with the thread under improper temperature conditions and with increased risk of injury to the operator from the unprotected parts.

.With the above consideration in mind it is, therefore, an object of the present invention to providenovel and improved thread tensioning mechanism for sewing machines, said mechanism being so constructed and arranged as to simplify substantially the operation of re-threading the machine.

Another object of the invention is the provision in a sewing machine of thread handling mechanism of such construction and arrangement that the operator will ofnecessity keep the cover for the thread handling devices closed while the machine is running.

With these objects in view, a feature of the present invention consists in the provision in a sewing machine having stitch forming and thread handling devices and a pivotally mounted cover for certain of said devices, of thread tensioning mechanism accessible for insertion of the thread therein when the cover is opened, .and operative Such supplementary tensioningto tension the thread only when the cover. is

closed. 1

More specifically, a feature of the invention consists in the provisionin a sewingmachine, having stitch forming and thread handling devices including a thread take-up, of a cover for enclosing certain of the devices, said cover being pivotally mounted to permit access to the same, and a frictional tension device acting with a yielding pressure on the thread between the take-up and the sewing point and comprising members having thread engaging surfaces, one of the members being carried by the cover,,whereby the device may be readily threaded when the, cover is open and the device rendered operative to tension the thread only upon closingthe cover.

In the drawings illustrating the preferred'embodiment of the invention, Figure 1 is a view' in front elevation of the head portion of a shoe sewing machine embodying the invention, showing the cover for the take-up mechanism in closed position, which mechanism is indicated in dotted line; Figure 2 is a view in side elevation, partly in section, of the machine adjacent the sewing point and showing a portion of the auxiliary thread tensioning mechanism, the covers for the tension wheel and take-up mechanism being largely broken away; and Figure 3 is a detail plan view, partly in section, of the auxiliary thread tension device.

The machine illustrated in the drawings is an outsole lockstitch shoe sewing machine more fully illustrated and described in .inventors application Ser. No. 76,924 above referred to, only so much of the machine being illustrated in the drawings as is necessary to a full understanding of the invention. The work support of the machine is indicated at 4, and the presser foot at'6, while the stitch forming and thread handling devices adjacent the sewing point include a curved hook needle 8, a curved awl II], a needle threading looper i2 and thread finger M. A rotary loop taker is mounted above the sewing point in a circular guideway IS in the machine frame I8, and the locking thread casein turn is "45 supported in a guideway in the loop taker. The various devices are actuated by connections from a sewing cam shaft 20 in the head of the machine.

The machine is provided with a take-up 22 by which the loop of the needle thread, after being carried over the locking thread case by the loop taker, is drawn into the work to set the stitch. The take-up 22 is secured to one end of a shaft 24 rotatably mounted in the front portion of the machine frame below the sewing point. 55

The shaft is rocked by connections from the cam shaft 28 to oscillate the take-up arm close to a stationary side flange portion 26 extending forwardly from the machine frame and provided at its forward edge with a sidewardly directed rim portion 2'5.

Each stitch is set against a uniform tension in the needle thread, this tension being provided by a tension wheel 28 rotatable in the main frame of the machine. The tension wheel is nor mally entirely enclosed by a hinged cover 38, and is provided with a brake 32, the adjustment of which is effected by a thumb nut 34. From the tension wheel the needle thread passes over an idler pulley 36 and about an auxiliary take-up 38, thence over idler pulleys 39 and to the pulley 62 on the main take-up lever 22. The thread, prior to passing over the tension wheel 28, is drawn through the usual wax pot, not shown.

To retain the thread in properly heated condition in its passage over the auxiliary and main take-

ups

38 and 22 respectively, and to shield the operator from the rapidly oscillating take-up lever, there is provided a cover 44 having a for wardly offset portion generally parallel to and adapted to cooperate with the rim portion 27 of the projecting flange 25 to form an enclosure for the take-up mechanism. The cover is mounted on the machine frame by means of a horizontal hinge 4-6 at its lower edge to permit the cover to be swung outwardly and downwardly away from the take-up 22 to render the needle handling devices accessible for re-threading and for repair and adjustment. A handle 68 on the cover enables the same to be opened and closed conveniently.

To assist in carrying out the looping operation by insuring that the needle thread will be stretched between the looper l4 and the thread finger It so as to engage and be retained in the needle hook, there is provided an auxiliary frictional tension device acting upon the needle thread between the take-up 22 and the looper Hi. In order that the re-threading operation may not be rendered more difficult by the addition of the said auxiliary tensioning device the mechanism thereof is mounted partly on the take-up cover M and partly on the flange portion 26 of the casing so that the device is opened automatically when the take-up cover is opened.

The thread tensioning mechanism comprises a plate 552 slidably mounted in the upper part of the flange 26 of the take-up casing, the plate being so positioned relative to the lead of the thread between the pulley 42 on the take-up lever 22 and the looper !2 that the thread is drawn to the sewing point across the face of the plate, as shown in Figure 2. A headed pin 52 (see Figure 3), secured at one end to the plate 50 and passing loosely through the side of the flange serves to hold the plate in position while permitting movement of the plate laterally. The plate is urged away from the flange and toward the portion if: of the cover M by small springs E l received in recesses in the flange 26.

The forwardly offset portion of the take-up cover M is formed along its upper edge with a suitable surface 56 substantially parallel to and arranged to cooperate with the plate 57.! of the tension device. When the cover 44 is swung open to expose the take-up mechanism, the surface 56 is moved forwardly out of alignment with the plate and the thread between the take-up lever 22 and the looper !2 passes loosely across the surface of the plate 50, as in Figure 2. When the cover is swung into the closed position shown in Figure 3, a bevelled surface 58 on the cover forces the thread to the right, the plate 50 yielding to permit the thread to enter between the parallel friction surfaces of the cover and plate.

By this arrangement of take-up cover and thread tensioning mechanism, not only is the operation of re-threading the machine substantially simplified, but also it is insured that the operator will close the cover before starting the machine, since the thread tens-ion necessary to the proper operation of the machine is obtained only with the cover in closed position.

While the invention has been illustrated and described as embodied in a lockstitch shoe sewing machine of particular construction and arrangement, the invention is not limited thereto in its application, and may be. embodied in sewing machines of other types. limited to the particular form and arrangement shown and described, but embraces other constructions and arrangements within the scope of the appended claims.

Having thus described the invention, what is n claimed is:

1. A sewing machine having, in combination, stitch forming and thread handling devices, a cover for enclosing certain of said devices, the

cover being movable away from closed position to permit access to the devices, and frictional thread tension mechanism comprising members having thread engaging surfaces arranged to act with yielding pressure on the thread between certain of the thread handling devices when the cover is in closed position, movement of the cover away from closed position causing the thread engaging surfaces to separate to permit insertion of the thread therebetween.

2. A sewing machine having, in combination, stitch forming devices comprising a hook needle and a take-up, a pivotally mounted cover to enclose or permit easy access to certain of the stitch forming devices, and a frictional tension device acting with a yielding pressiu'e on the thread bethe point of operation of the needle, and comprising members having parallel thread engaging surfaces disposed at right angles to the take-up shaft, one of said surfaces being carried by said cover.

4. A sewing machine having, in combination, stitch forming devices comprising a hook needle and a take-up, a shaft on which the take-up is mounted, a stationary guard at one side of the path of movement of the take-up, a removable cover arranged when in position to surround the other side of the take-up path, and a frictional tension device acting with a yielding pressure on the thread between the take-up and the point of operation of the needle and comprising n1c1nbers having thread engaging surfaces, carried by said guard and said cover, respectively.

OTTO R. 'rIAAS.

Nor is the invention