US2520211A - Shoe sewing machine - Google Patents

Description

Aug. 29, 1950 L. T. JAMES SHOE SEWING MACHINE Filed May 20, 1948 28 m ,1- IM MMH I Patented Aug. 29, 1950 UNITED STATES PATENT OFFICE 2.5mm snot SEWING MACHINE (Lawrence T. James, Cape Girardeau, Mo,v as signor to United Shoe Machine y Corporation, Flemington, N. J a corporation of New Jersey Application May 20, 1948, Serial No. 28,181

ZClaims. l

The present invention relates to improvements in back rests for inseam sewing machines such as are used for sewing uppers to the soles of turn shoes or the welts and uppers to the insoles of welt shoes and is hereinafter illustrated as being an improvement in the back rest construction disclosed in United States Letters Patent No. 2,383,530, granted August 28, 1945, upon application or L. L. Barner.

The machine of the patent is provided with a backrest comprising a button rotatable on a back rest slide about a fixed axis substantially parallel to a line tangent to that portion of the curved hook needle which engages the work. In order to prevent varying shapes and curvatures of the shoe surface from engaging the edge of the rotatable button of the patented machine, the work engaging face of the button is formed as a. convex segment of a sphere. The extent of the spherical face on the button is made sufficient to e prevent contact between the edges of the button and the shoe, thus reducing the tendency to mark or otherwise injure the surface of the shoe upper. While the patented construction is effective for steadying the shoe and reducing the frictional rubbing action of the shoe along the back rest the tendency to mark the upper of a delicately finished shoe is not entirely eliminated with the patented machine by reason of the restricted area of contact between the button and the abruptly curved surfaces on the shoe.

The object of the present invention, accordingly, is to improve the operation of the back rest in the patented construction to reduce still further the tendency to mark or otherwise damage the surface of a shoe upper being sewn by increasing the area of contact between the button and the shoe while retaining the advantage of the patented construction in eliminating contact with the edges of the shoe on the back rest. For this purpose the back rest slide of the machine herein disclosed is provided with a flattened button which is mounted for free swiveling movement on a spherically headed stud carried by the back rest slide about a center in close proximity to its work engaging face to enable it to orient itself automatically as the sewing operation progresses with its face always disposed tangentially to the surface of the shoe being operated upon, thus insuring the largest practicable area of contact between the button and the shoe surface. Preferably, the spherically headed stud is mounted in a horizontal position on the back rest slide.

These and other features of the invention con- 2 sist of certain constructions, combinations and arrangements of parts hereinafter claimed, the advantages of which will readily be understood from the following description taken in connection with the accompanying drawings, in which:

Fig. l is a view in right side elevation of a portion of a shoe sewing machine embodying the present invention;

Fig. 2 is a detail View on an enlarged scale of some of the parts of the machine illustrated in Fig. 1 together with a shoe shown in section taken at the sewing point while sewing along the shank of the shoe;

Fig. 3 is a similar view illustrating the positions of the parts while the toe of the shoe is being sewn; and

Fig. 4 is a detail plan view illustrating the position of the back rest button in the machine with relation to a shoe while sewing along the ball portion of the shoe.

The machine illustrated in the drawings is arranged for sewing a welt 2 to a Goodyear type of shoe 4 and is provided with the usual stitch forming devices including a curved hook needle 6, a looper 8, a thread finger H3, a welt guide [2 and a back rest or bunter slide [4 pressed yieldingly within a horizontal guideway l6 toward the front of the machine. During sewing operations the slide I4 is moved as the position of the shoe is changed and is intermittently locked and released by mechanism IB similar to that disclosed in United States Letters Patent No. 1,142,157, granted June 8, 1915, in the name of Andrew Eppler and in the Barner patent above identified. Other operating parts of the machine are similar to those disclosed in these patents except for the work engaging end of the back rest slide.

The forward end of the back rest slide in the machine of the Barner patent is formed with an offset lug corresponding to the lug, indicated at 20, having a vertical slot 22 within which is clamped a horizontal bearing for a rotatable button having a spherical work engaging surface. The button is arranged to engage the upper of a shoe being sewn in different relations as the sewing progresses to steady the shoe and to resist the force applied to the shoe by the stitch forming devices, the locking mechanism I8 acting at the proper times to hold the back rest slide against movement.

As the shoe engages the button of the Barner machine above or below the axis of its rotation,

.rotary movement is imparted to the button in one direction or the other depending upon the position of engagement. In this way the scufiing or frictional action between the shoe upper and the button surface is substantially reduced. However, the nature of the contact between the shoe and abutment as a result of the spherical surface of the button necessarily restricts the area of contact between the two so that if heavy pressure is exerted on the shoe, particularly with a shoe having a light colored upper, there may still be a tendency to mark the upper.

In order to reduce to a minimum the tendency of the back rest in the machine of the present invention to mark or otherwise injure the surface of a shoe upper, the back rest slide I4 has secured within the slot 22 of its forward end a spherically headed stud 24 on the head of which is loosely mounted a flattened button 26. The button 26 is thus mounted for universal swiveling movement about the spherical head of the stud, the button being provided with a socket for the spherical head of the stud in close proximity to its flat work engaging surface. At its circumference the botton is curved away from a flat work engaging surface to avoid the possibility of scuifing or interfering with seams in the shoe upper as they move across its surface.

The stud 24 is clamped within the slot of the lug 20 in the back rest slide in a suitable adjusted position vertically of the slot by a pair of nuts 28 on the threaded portion of the stud. To prevent lateral movement of the stud in the slot and to guide the vertical movement, the forward end of the threaded portion carries a flat-sided washer 3!], the flattened edges of which are slidably mounted within grooves 32 formed above and below the slot in the lug. The rear surface of the lug is engaged also by a washer 34.

The arrangement of the flat-faced button for swiveling movement on the stud 2G is efiective in reducing the tendency to mark the surface of a shoe upper by reason of its relatively large area of engagement with the surface of the upper, the greater the area of engagement the less the pressure per unit area. Thus the pressure per unit area of the upper against the flat surface of the button 26 in the present machine is less than with the spherically faced button of the Barner machine. Furthermore, the button 26 of the present machine is also free to rotate as the surface of a shoe upper is carried past it, thus retaining the advantages of the rotary button of the Barner machine. A further advantage exists in the use of the present back rest button in that it maintains automatically a contact with its flat work engaging surface always in a plane tangent to the curved shoe upper surface, thus equalizing the pressure throughout the area of contact. For instance, in sewing along the inside shank of a shoe as in Fig. 2 the center of the area of contact between the upper and the button is below the axis of the stud 24. In sewing about the toe portion of a shoe as in Fig. 3 the center of the area of contact between the upper is moved above the axis of the stud 24. Between these points as in Fig. 4 the button moves to bring the center of contact area to one side of the axis of the stud. When no shoe is presented to the machine-the button swings about the spherical head of the stud to a downwardly and rearwardly inclined position where it is held by the engagement of its socket portion with the neck between the spherical head and the stud 24 (see Fig. 1).

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

1. An inseam shoe sewing machine having stitch forming devices including a curved hook needle and a back rest slide, in combination with a flattened button and a spherically headed stud carried by said slide on which the button is mounted for universal swiveling and rotational movement about a center in close proximity to the flattened work engaging face of the button.

2. An inseam shoe sewing machine having stitch forming devices including a curved hook needle and a backrest slide, in combination with a flattened button having a socket in close proximity to its work engaging surface and a spherically headed stud carried in a horizontal position by said slide on the head of which the socket on the button is loosely mounted for universal swiveling and rotational movement.

LAWRENCE T. JAMES.

REFERENCES CITED UNITED STATES PATENTS Name Date Barner Aug. 28, 1945 Number

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