US2731930A - Galkin - Google Patents

Description

J. GALKIN Jan. 24, 1956 PORTABLE THREAD SEVERING ATTACHMENT F'OR SEWING MACHINES 4 Sheets-Sheet 1 Filed March 29, 1954 llllll.

llllilllllullm ATTORNEY J. GALKIN Jan. 24, 1956 PORTABLE THREAD SEVERING ATTACHMENT FOR SEWING MACHINES 4 Sheets-Sheet 2 Filed March 29, 1954 INVENTOR BW MM JOSEPH GALKIN NGI ATTORNEY Jan. 24, 1956 J. GALKIN 2,731,930

PORTABLE THREAD sEvERTNG ATTACHMENT FOR SEWING MACHINES Filed March 29, 1954 4 Sheets-Sheet 3 FIGA Y. E :r

JOSEPH GALKIN INVENTOR ATTORNEY Jan. 24, 1956 J. GALKIN 2,731'930 PORTABLE THREAD SEVERING ATTACHMENT FOR SEWING MACHINES Filed March 29, 1954- 4 Sheets-Sheet 4 JOSEPH GALKIN FIG. 5 B

ATTORNEY United States Patent O PORTABLE THREAD SEVERING ATTACHMENT FORv SEWING MACHINES Joseph Galkin, New York, N. Y.

Application March 29, 1954, Serial' No. 419,491

4 Claims. (Ci. 112--252) This invention relates to a portable attachment for sewing machines, for use in severing the chain of stitching between two successively stitched fabric sections and without requiring that the operator handle a pair of scissors.

In my patent for thread severing mechanism for sewing machines, Patent No. 2,424,391 dated July 22, 1947, I have disclosed an attachment specially designed for severing the chaining thread. between successively stitched articles, on an overseaming sewing machine. The said attachment is positioned rearward of the feed-dog and comprises. a groove positioned rearward of the line ofA seam f ormatiom and a pair of coacting cutting blades, the movable blade being positioned to` swing across the line of Seam formation into cutting engagement with the fixed blade.

In my improved chain severing disclosure herewith I provide a portable attachment which may be installedr on the base of any kind of sewing machine having an overhanging head and without drilling any holes in the sewing machine body or in the head cover plate and which may be quickly removed from the sewing machine when desired.

Thel chain-severing mechanism herewith, comprises a movable blade and a stationary blade. The invention consists in the mechanism whereby the movable blade of the severing device is connected to. and operated from a horizontal shaft supported at the rear of the head of the sewing machine and driven by the main shaft of the sewing machine.

This invention embodies certain features of construction, whereby the chain to be severed is. guided into the path of the movable blade. The movable blade is held under tension by a spring mounted on a pivot4 screw which holds the movable blade against the face of the stationary blade, so that the proper shear cut will be made to sever the chain of stitching.

An important object of this invention resides in the structure whereby the bracket base is provided with a plurality of apertures which are drilled before to align and coact with the threaded apertures provided in the work-supporting base of the sewing machine.

Another object of this invention is to provide a mounting permitting coacting relation therewith of a feed-roller, and a resilient platform pressing against the feed-roller, and means for driving the feed-roller from the main shaft of the sewing machine.

With the above and other objects in view, the invention will be hereinafter more particularly described, and the combination and arrangement of parts will be shown in the accompanying drawings and pointed out in the claims which form part of this specification.

Reference will now be had to the drawings, wherein like.y numerals of reference designate corresponding parts throughout the several views, in which:

Figure 1 is a front view of a self-contained threadi severing attachment mounted rearward of a sewing machine, the sewing machine being shown in dot-and-dash lines.

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Figure 2 is a top plan view of the thread severing attachment shown in Figure l.

Figure 3 is an end elevation of the thread severing attachrnent shown in Figures l and 2, the base being broken away to show the mounting of a pivot pin.

Figure 4 is a rear view of a fragmentary portion of the attachment.

Figure 5k is an end elevation of the thread severing attachment mounted on a sewing machine, the feed-roller and platform being shown in dot-and-dash lines.

Figure 6.is a perspective View of a bifurcated leaf spring which,4 presses the platform against the feed-roller.

Figure 7 is a top plan view of an electric motor and universal joint which connects the motor to. the bracket shaft.

In the illustrated embodiment of the invention, the numeral 10. indicates a sewing machine comprising a at bed or work-supporting base 11 having an upright tubular standard 12 extending therefrom and having an upper overhanging horizontal arm 13 terminating in a hollow upright head 14. The head 14 terminates in. an upright end, face 1610 which is attached a cover or head plate` 17'. In the head 14 is journalled a needle-bar 1S carrying a needle 19. The material worked upon is held down by a presser-.bar 20.

The presser-bar 2l) rests on a cloth plate 22 secured to and above the work supporting base 11. A drive shaft 23 is suitably journaled in the base portion of the machine and from which the stitch forming and feeding elements are driven, as is, well known in the art. The material is moved, across the work support by a feed-dog 24, which is moved back and forth and up and down in the usual manner.

Thel main object of this invention is to provide a portableattachment which may be detachably mounted on a sewing machine base rearward of the head of the machine for severing the chain of stitching between twoA successively stitched fabric sections.

The thread severing attachment is identified by the numeral 25 and` comprises a base-plate 26 having apertures 2]. Flat head screws 28 passing through the, said apertures are` threaded in suitable threaded apertures 29 in the work-supporting base 11 of the sewing machine 10, and secure the base plate 26 to the base 11.

A bracket 30 having a base plate 31 is suitably fastened to the base-plate 26 by bolts 32. The bracket has an overhanging head 33 which terminates at its free end in anv upright end face 3.4. A plate 35 is attached to. the heady 33 by screws 36. The plate 35 has. a forwardly extending arm 37 t0 which is attached a generally rectangular housing 38 by screws 39. The housing 38 has a vertical. front face toy which is attached a stationary blade 40 by screws 41.

As shown in Figure 1, the lower end portion of the stationary blade 40 has an upright opening or guideway 45 between twoy legs 46 which define the lower portion of, said blade. The guideway 45 terminates in an angular opening 47 having its apex at its upper end portion.

One of the angular sides 48 of the opening 47 is undercut at its rear face to provide a cutting edge. The stationary blade 40 has a pivot screw 49 on which is mounted a movable blade 50 having an angular cutting edge 5,1 at its front face and in co-acting cutting relation with theA angular side 4S of the opening 47. The movable blade 50 has a substantially horizontally positioned extension 52 at,v the free end portion of which is a threaded pin S3. It is to be noted that a hollow spring 42 is mounted on the pivot screw 49 and pressed against the movable blade 50 by a threaded nut 43. This causes the blades to be in resilient engagement.

Rotatably mounted in bearings 55, 5S on the bracket 25 is a shaft 56 which terminatesat one end adjacent the 3 threaded pin 53 on the movable cutting blade 50. A11 eccentric pin mounting 57, having a pin 57 is secured to the shaft 56 in alignment with the threaded pin 53 and carries a link 58.

Suitably secured to the housing 38 is an angular member 59 having a rectangular upright guideway 60 in which a slide bar 61 is mounted in upright position. The upper end portion of the slide bar is secured to the link 58 by a pin 62. The lower end portion of the slide bar 61 has a horizontal slot 63 in which the pin 53 on the movable blade 50 is slidably mounted. At the other end of the shaft 56 is a pulley 64 connected by a belt 65 to a pulley 66 on the drive shaft 23 of the sewing machine 10.

In operation, the operator may, after the stitching of a fabric section is finished, pick up the said section to permit the cutting blades to sever the chaining thread which normally connects two consecutively stitched fabric sections. It will be seen that with the mechanism heretofore described, the operator can sever the chaining thread without the necessity of picking up a pair of scissors for every section stitched.

An embodiment of the severing mechanism which severs` the thread completely automatically, involves the addition of a feed-roller crosswise of the line of stitching and of a pivoted platform which is resiliently pressed against the roller.

The platform 70 is a sheet metal frame of generally rectangular cross-section. One end is rolled and embraces a pin 71 mounted in a cavity 72 in the base plate 26 of the attachment. The opposite end 73 of the platform 70 is slidably mounted vertically in a slot 74 in the base 26.

A leaf spring 75 has its lower end suitably secured to the base 26. The upper end of the spring 75 is in slidable contacting relation with the lower surface 76 of a horizontal portion 77 of the platform 70.

The bracket shaft 56 carries a sprocket wheel 80 and a sprocket chain 81. The chain extends downwardly into engagement with a sprocket wheel 82 carried by a shaft 83. The shaft 83 is rotatably mounted in a stationary bearing 84 integral with the plate 35. Mounted on the shaft 83 is a feed-roller 85 having a knurled outer periphery and which is of a diameter large enough to contact the platform 70 under pressure exerted by the platform spring 75. The stitched fabric passes over the platform and is gripped by the feed-roller 85 and pulled at a slightly higher speed than the feed-dog 24 of the sewing machine.

It is to be noted that the threaded apertures 29 in the work-supporting base 11 of the sewing machine 10 are those provided in all sewing machines of the above type and that the apertures 27 in the bracket 30 are drilled beforehand to align and coact with the apertures 29. Accordingly, the thread severing attachment 25 can be readily attached to a sewing machine of the above type in a few minutes without the necessity of drilling holes in or defacing any portion of the sewing machine.

Figure shows a sewing machine having my invention applied thereto and shows in dot-and-dash lines the addtion of a feed-roller 85 and a resiliently mounted platform 70 pressing against the feed roller and which converts the attachment herewith to a fully automatic thread severing mechanism.

Figure 6 is a perspective view of the leaf spring 75 showing a bifurcated upper portion 86. This spring presses the platform 70 upwardly against the feed-roller 85 at two points 87, 87 to permit the platform to tilt slightly when passing over seams of irregular thickness. The spring 75 has apertures 88 for screws 89 threaded in the base-plate 26. To permit this tilting motion of the platform, the pivot pin 71 is mounted with a slight clearance in the cavity 72.

It is also to be noted that when a feed-roller is used, the speed of the feed-roller must be slightly faster than the feed of the feed-dog 24 to exert a slight tension on the chaining thread. For this purpose the pulley 88 on the main shaft 23 is much smaller in diameter than the di- 4 ameter of the pulley 64 on the bracket shaft 56. This reduces the speed of the bracket shaft to considerably less than the speed of the main shaft pulley to prevent excessive high speed operation of the feed-roller but somewhat faster than the feed-dog.

It is also to be noted that I may attach a low speed electric motor 96 and a universal joint 91 to the free end portion of the bracket shaft 56 for rotating said shaft so as to feed the fabric and so that the attachment 25 is completely independent of operation by the sewing machine. This makes possible the mounting of the complete attachment on a sewing machine without drilling or cutting or in any way affecting the sewing machine and the attaching is accomplished in only a few minutes.

In accordance with the patent statutes I have described and illustrated the preferred embodiment of my invention, but it will be understood that various changes and modiiications can be made therein without departing from the spirit of the invention as defined by the appended claims.

I claim:

l. In a sewing machine comprising a work-supporting base, a main shaft, a needle, and a feed-dog; a portable thread severing attachment having a base fixed to said work-supporting base rearward of the line of stitching for severing the chaining thread between successively stitched articles, including a bracket having a head and a lateral extension having an upright guideway, a stationary cutting blade fixed to said head extension and having a pivot screw and a guideway in alinement with the line of stitching, a. shaft rotatably mounted on said bracket and having an eccentric pin at one end, a link mounted on said eccentric pin, a movable blade pivotally mounted on the pivot screw of said stationary blade and having a substantially horizontal extension and a pin at its free end, spring means mounted on said pivot screw, pressing against said movable blade and biasing said movable blade against said stationary blade, a slide bar mounted in said upright guideway and having a slot at its lower end for receiving the pin on said movable blade and being thereby operatively connected to said movable blade, said slide bar being pivotally connected at its upper end to said link, whereby rotation of said bracket shaft will actuate said movable blade into cutting relation with said stationary blade, and means at the free end of said attachment shaft for rotating said shaft from the main shaft of said sewing machine, the lower portion of said stationary blade having forwardly extending arms designed to cover the major portion of said pivotally mounted cutting blade and protect the articles being stitched from contact with or damage by said movable cutting blade.

2. In a sewing machine comprising a work-supporting base, a main shaft, a needle, and a feed-dog; a portable thread severing attachment having a base fixed to said work-supporting base rearward of the line of stitching for severing the chaining thread between successively stitched articles, including a bracket having a head and a lateral extension having an upright guideway, a stationary cutting blade fixed to said head extension and having a pivot screw and a guideway in alinement with the line of stitching, a shaft rotatably mounted on said bracket and having an eccentric pin at one end, a link mounted on said eccentric pin, a movable blade pivotally mounted on the pivot screw of said stationary blade and having a substantially horizontal extension and a pin at its free end, spring means mounted on said pivot screw, pressing against said movable blade and biasing said movable blade against said stationary blade, a slide bar mounted in said upright guideway and having a slot at its lower end for receiving the pin on said movable blade and being thereby operatively connected to said movable blade, l

said slide bar being pivotally connected at its upper end to said link, whereby rotation of said bracket shaft will actuate said movable blade into cutting relation with said stationary blade, and means at the free end of said attachment shaft for rotating said shaft from the main shaft of said sewing machine.

3. In a sewing machine comprising a work-supporting base, a main shaft, a needle, and a feed-dog; a portable thread severing attachment having a base plate attachable to said work-supporting base rearward of the line of stitching for severing the chaining thread between successively stitched articles, including a bracket having an overhanging head and a lateral extension having an upright guideway, a stationary cutting blade fixed to said head extension and having a pivot screw and a guideway at its lower end portion in alinement with the line of stitching, a shaft rotatably mounted on said bracket and having an eccentric pin at one end, a link mounted at its upper end on said eccentric pin, a movable blade pivotally mounted on the pivot screw of said stationary blade and having a substantially horizontal extension and a pin at its free end, spring means mounted on said pivot screw, pressing against said movable blade and biasing said movable blade against said stationary blade, a slide bar mounted in said upright guideway and having a horizontal slot at its lower end for receiving the pin on said movable blade to permit movement of said slide bar in linear direction while said blade pin moves in an arcuate direction, said slide bar being pivotally connected at its upper end to the lower end portion of said link, whereby rotation of said bracket shaft will actuate said movable blade into cutting relation with said stationary blade, and a pulley at the free end of said attachment shaft for rotating said shaft from the main shaft of said sewing machine, the lower portion of said stationary blade having forwardly extending arms designed to cover the major portion of said pivotally mounted cutting blade and protect the articles being stitched from contact with or damage by said movable cutting blade.

4. In a sewing machine comprising a work-supporting base, a main shaft, a needle, and a feed-dog; a portable thread severing attachment having a base plate attachable to said work-supporting base rearward of the line of stitching for severing the chaining thread between successively stitched articles, including a bracket having an overhanging head and a lateral extension having an upright guideway, a stationary cutting blade fixed to said head extension and having a pivot screw and a guideway at its lower end portion in alinement with the line of stitching, a shaft rotatably mounted on said bracket and having an eccentric pin at one end, a link mounted at its upper end on said eccentric pin, a movable blade pivotally mounted on the pivot screw of said stationary blade and having a substantially horizontal extension and a pin at its free end, spring means mounted on said pivot screw, pressing against said movable blade and biasing said movable blade against said stationary blade, a slide bar mounted in said upright guideway and having a horizontal slot at its lower end for receiving the pin on said movable blade to permit movement of said slide bar in linear direction while said blade pin moves in an arcuate direction, said slide bar being pivotally connected at its upper end to the lower end portion of said link, whereby rotation of said bracket shaft Will actuate said movable blade into cutting relation with said stationary blade, and drive means connected with the free end of said attachment shaft for rotating said shaft, the lower portion of said stationary blade having forwardly extending arms designed to cover the major lower portion of said cutting blades and protect the articles being stitched from contact with or damage by said blades.

References Cited in the iile of this patent UNITED STATES PATENTS 1,613,540 Siegel Ian. 4, 1927 1,748,904 Sanderson Feb. 25, 1930 2,151,438 Pierce Mar. 28, 1939 2,376,417 Chudner May 22, 1945 2,426,026 Kehrer Aug. 19, 1947

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