US2233413A - Sewing machine - Google Patents

Description

March 1941- N. F. HOPKINS EIAL 2,233,413

SEWING MACHINE Filed Jan. 27, 1938 M, zizbw%4 7 7 Patented Mar. 4, 1941 UNITED STATES PATENT OFFICE 2,233,413 SEWING MACHINE Application January 27, 1938, Serial No. 187,198

5 Claims.

The present invention relates to Wax thread shoe sewing machines.

It is common practice in manufacturing cemented shoes to cut the outsole to size with little 5 or no trimming margin, and to attach to such an outsole, before assembling with the insole and upper, a welt having the grain surface exposed on the projecting margin of the outsole around the forepart with a line of stitches on such surface to give the appearance of a Goodyear welt outseam.

When such an outsole is first mounted on the lasted shoe, the outsole is in temper to render it pliable and easily molded under pressure to conform to the curved bottom of the last. As a result of this molding operation, the marginal portions, which are originally flat and in the same plane with the bodyof the outsole with their edge surfaces at right angles thereto and parallel to one another, are bent into close fitting relation with the curved bottom of the last so that the edge surfaces of the outsole are no longer at right angles to such a plane and parallel toeach other, but are substantially inclined inwardly towards the center of the shoe. As a result, they are plainly visible when viewed from above and detract from the appearance of the finished shoe.

In order'to avoid this defect, the edge surfaces of the outsole are trimmed to restore their parallel relation, but since the bending of the marginal portions of the outsole in the molding operation imparts an inward inclination to the stitches similar or corresponding to that imparted to the edges of the sole, care must be exercised by the operator that in the trimming operation those portions of the stitches adjacent the tread surface of the outsole are not cut or damaged.

It is an object of the present invention to avoid the difiiculty above described and to provide a novel and improved sewing machine for sewing a welt with its edge in uniformly accurate registration with the edge of an outsole before the outsole is attached to the upper of a shoe, the seam being formed at a substantial inclination from a line normal to the sole and outwardly from the shoe on the welt side of the sole and close to the edges of the outsole, so that when the sole with its attached welt is molded to the curved bottom of the shoe, the inclined seam will be brought approximately parallel on the opposite sides of the shoe, and the edges of the sole may be trimmed to proper shape and close to the stitches without danger of cutting into them at the tread face.

'With this object in view, a featureof the present invention contemplates the provision in a hook needle lockstitch outsole sewing machine having an awl and a welt guide of a work supporting means for supporting the welt and outsole and presenting them to the sewing instrumentalities at 5 such an angle with respect to the paths of the needle and awl that the completed stitches passing from the welt to the tread surface of the outsole are substantiallyinclined inwardly towards the middle part of the tread surface. The sup- .10 porting means, preferably in the form of a fiat plate, are of sufiicient size to underlie not only the welt but a substantial portion of the outsole and to hold it from being twisted or bent by the operator in maintaining the outsole in proper position against the thrust of the awl during the sewing operations. Preferably a curved needle and a curved awl are employed and the inclination of the work supporting means is such that the work engaging surfaces thereof lie in parallel planes intersecting the needle and awl paths, and passing at the same side of and below the axis of the needle and awl carrying stud.

These and other features of the invention will be clearly understood from an inspection of the accompanying drawing in which Fig.1 is a View in side elevation of a portion of a sewing machine embodying the present invention, showing the work positioned for the welt attaching operation with the outsole tread surface up; Fig. 2 is a top plan view of the work supporting plate detached with the position of the outsole indicated in' broken outline; Fig. 3 is a perspective View of a portion of a shoe outsole with the thread surface down, showing the welt both before and after the sewing operation; and Fig. 4 is a sectional view of a shoe in which the outsole with attached welt has been incorporated and the edges of the outsole have been trimmed in accordance with the usual practice, the portions of the outsole and welt which have been removed by the trimming operation being shown in broken outline.

Referring to Fig. 3, the outsole, indicated at It], is cut accurately to size with edge surfaces II at opposite sides parallel and square with the thread. The outsole has on its flesh side a smooth, reduced outer marginal band l2 and an inner roughened band 14, the grain surface 16 of the treadface remaining without modification. The outer band I2 is reduced to a suitable angle with relation to the grain surface and has attached to it a welt strip [8 formed with a narrow finished grain strip 2i] and a flesh surface skived at an angle to (30- operate with the angle of the band I2. The relation of the welt with the marginal portions of the outsole is such that the grain strip 20 of the Welt will be approximately parallel to the grain surface I6 of the outsole, while the roughened band M will be exposed inwardly beyond the welt in order to adhere more readily and firmly with the cement by means of which the sole is attached to the insole and upper.

The welt is secured to the outsole by means of a lockstitch seam 22, the stitches of which pass from the middle of the grain strip 20 on the welt through the welt and outsole at such an angle or inclination to the grain side It of the outsole that the seam is positioned nearer the middle of the outsole on the grain side than 'on the flesh side. Due to the thickness and density of the work, a hook needle machine is preferably employed, and the work is presented to the machine so that the shuttle thread will be laid along the grain side l6 of the outsole, and the stitches are set with the locks between the threads embedded within the substance of the outsole.

The machine for sewing the seam 22, according to the present invention, is arranged to insert the stitches at an angle of substantially '70 degrees with respect to the tread face of the flat outsole. When such an outsole is applied to the bottom of a lasted shoe, as indicated at 24, in Figure 4, and is pressed into uniform contact with the curved bottom thereof, a corresponding curvature'will be imparted to the sole and, as a result, the edge surfaces at opposite sides of the sole which originally were parallel will be thrown out of parallel relation and will now incline in- .wardly toward the middle of the shoe, as indicated in dot-dash lines 26 in Fig. 4. The stitches of the seam 22, however, which originally were inclined inwardly towards the middle of the tread surface l6, are now brought to or towards a parallel relation, so that, when the opposite edges of the outsole are trimmed to restore their parallel relation, the stitches will be no closer to the trimming cutters of the trimming machine at the tread side of the outsole than at the welt side. This permits the stitches to be inserted in the outsole much closer to the edge than is possible when the stitches are inserted normal to the fiat outsole in the usual way, which is a feature of advantage because when the stitches are inserted close to the edge, there is no substantial waste of leather,-as when a Wide trimming margin must be provided, it being necessary to trim only the corner at the tread of the outsole, as indicated in the dot-dash lines 26 of Figure 4.

The stitch form-ing devices of the machine comprise a curved hook needle 28, a curved awl 30, oscillating about the axis of a needle and awl stud 32, a shuttle 34, and other mechanisms similar to thoseillustrated and described in the patents to French and Meyer No. 473,870 and Gouldbourn et al. No. 2,056,670. It is preferred to employ a curved needle machine for this work because the unsupported length of the awl as it penetrates the work to form a perforation for each stitch is much less than in a straight needle and awl machine. Consequently, the awl is stiffer and is much less likely to be bent or to causethe work to be displaced during the pene trating stroke.

To..support and present the work in the machine at the proper angle during the formation of each stitch, there are provided an inclined work supporting plate 36, a presser-foot 38 also having an inclined work engaging surface, a. back gage 40, and a welt guide 12 in the plate 36 for laying the welt l8 accurately on the reduced margin I2 of the outsole. The presser-foot is pivotally mounted at M in the usual way to clamp and release the work in timed relation to the other stitch forming devices.

The work engaging face of the work support-, ing plate 36 and also of thepresser-foot 38 when the latter is in engagement with the work, are so disposed that they lie in parallel inclined planes which pass rearwardly and downwardly beneath the awl stud 32 and at some distance below the same. Due to the angular relation between these work supporting surfaces and the paths of the needle and awl, there is a tendency for the work to' be moved-outwardly away from engagement with the back gage 40 during the penetrating stroke of the awl. To overcome this tendency, it is necessary to apply a definite inward pressure against the outer edge surface of the outsole as it is being fed throughthe machine. Such a pressure, however, against the outer edge or elsewhere along the outsole, may tend to bend or distort the outsole to such an extent that often after the welt is attached a permanent bulge would be present. When a bulging outsole is applied to the shoe, the angular relation of the stitches will not be the same as when the outsole is applied in a perfectly flattened condition, and

when the outsole is molded, the angle of the stitches will vary so that the seam is not evenly spaced from the edges.

To enable the operator to hold the outsole firmly against the back gage 49 without bending or distorting the outsole in proximity to the stitching point, the work supporting plate 36 extends laterally in the line of the feed in both directions and also transversely thereto from the front of the machine so that a relatively large area of the outsole is engaged and supported.

With such a support, the outsole is held at the proper inclination and in such a position that it is easily guided by the operator, a downward and inward pressure against the outsole causing the latter to be held fiat on the plate 36 and firmly against the back gage 40, with no liability of bending or distortion.

The process of making shoes herein disclosed forms the subject-matter of the present inventors co-pending application Ser. No. 289,424 of August 10, 1939.

The invention having thus been described, what is claimed is:

1. A lockstitch machine for sewing a welt to the marginal portion of an unattached outsole having, in combination, stitch forming and work supporting devices including a hook needle, a shuttle, a work piercing awl, a welt guide,a back gauge for guiding the edges of the welt and outsole into accurate registration, and means for supporting the outsole and welt with their surfaces in planes inclined to the paths of the needle and awl through the work at an angle in the order of and for holding the Welt and sole against displacement by the operator or by the component lateral thrust of the stitch forming devices along said planes to cause the completed stitches passing from the welt to the tread surface of the sole to be inclined in a uniform manner at a predetermined angle towards the middle part of the tread surface of the sole, said means including a work support inclined to the paths of the needle and awl through the work positioned in proximity to the stitching point and of a substantial length and of a Width relative to the line of feed at least substantially half the width of the sole at its narrowest point to engage and support the welt and a substantial length and width of the sole.

2. A lockstitch machine for sewing a welt to the marginal portion of an unattached outsole having, in combination, a hook needle and a shuttle at one side of the work, a work piercing awl and a welt guide at the other side of the work, a back gauge for guiding the edges of the Welt and outsole into accurate registration, and means for supporting the outsole and welt with their surfaces in planes inclined to the paths of the needle and awl through the work at an angle in the order of 70, and for holding the welt and sole against displacement by the operator or by the outward thrust of the awl to cause the completed stitches passing from the welt to the tread surface of the sole to be inclined in a uniform manner at a predetermined angle towards the middle part of the tread surface of the sole, said means including a work supporting plate inclined to the paths of the needle and awl through the work positioned in proximity to the stitching point and of a length and width relatively to the line of feed to engage and support the welt and a substantial length and width of the sole.

3. A lockstitch machine for sewing a welt to the marginal portion of an unattached outsole having, in combination, a curved hook needle and a shuttle at one side of the work, a work piercing curved awl and a welt guide at the other side of the work, a back gage for guiding the edges of the welt and outsole into accurate registration, and a flat work support positioned at the front of the machine and inclined downwardly and rearwardly thereof for presenting the outsole with tread face up to the sewing instrumentalities and at an angle in the order of 70 to the path of movement of the needle and awl through the work to cause the line of stitches to be inclined toward the middle of the outsole, said work support being of a length and width relatively to the line of feed to engage and support the marginal portion of an unattached outsole having, in combination, a curved hock needle and a shuttle at one side of the work, a work piercing curved awl and a welt guide at the other side of the work, a back gage for guiding the edges of the welt and outsole into accurate registration, and work clamping means for supporting the welt and outsole adjacent the stitching point, said clamping means comprising a work support and a presser-foot, the supporting surfaces of which lie substantially parallel during operation of the machine in planes intersected by the paths of movement of the needle and awl through the work at an angle in the order of 70 and inclined to pass the axis of the needle and awl stud on the awl side thereof said work support being of a substantial length and of a width relative to the line of feed'at least substantially half the width of the sole at its narrowest point to engage and support the welt and a substantial length and width of the sole.

5. A lockstitch machine for sewing a Welt to the marginal portion of an unattached outsole having, in combination, stitch forming and work supporting devices including a hook needle, a shuttle, a work piercing awl, a welt guide, a gauge for guiding the edges of the welt and outsole into accurate registration, and means for supporting the outsole and welt with their surfaces in planes inclined to the paths of the needle and awl through the work at an angle in the order of 70, and for holding the welt and sole against displacement by the operator or by the component lateral thrust of the stitch forming devices along said planes to cause the completed stitches passing from the welt to the tread surface of the sole to be inclined in a uniform manner at a predetermined angle towards the middle part of the tread surface of the sole, said means includin a work supporting plate inclined to the paths of the needle and awl positioned in proximity to the stitching point and. of a length and width relatively to the line of feed to engage and support the welt and a substantial length and width of the sole.

NATHAN F. HOPKINS. WILLIAM A. BERTRAND.

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