US2569725A - Vulcanization last - Google Patents

Description

Oct. 2, 1951 I MASEK 2,569,725

NIZATION LAST Patented Oct. 2, 1951 VULCANTZATION LAST Josef Masek, .Zlin; Czechoslovakia, assignor to Bata, Narodni Podnik, Zlin, Czechoslovakia,

Application January 20, 1948, Serial No. 3,195 In Czechoslovakia January 20, 1947 The present invention relates'to a vulcanization last provided with resilient portions. Inthe manufacture of fabric or leather shoes having a pressed-on sole, vulcanization lasts with a resilient insertion piece have been used to secure exact cutting of the edge of theborder in such a way as to avoid damage of the upper part of the shoe. For this purpose a groove has been milled in the last at the same level with the line along which the edge of the border is to be out off during the pressing operation. The groove has been filled with an unvulcanized rubber mixture which subsequently undergoes vulcanization on the last itself. However, the rubber filling of the groove hardens after a certain time due to the action of heat and so loses its resiliency. It has been necessary. therefore, to replace it by a fresh filling. Since in the majority of cases the groove in the last has been dovetailed, and also due to the vulcanization of the rubber mixture, a relatively strong connection is produced between rubber and metal, so that considerable force has been necessary to remove the old rubber filling from the groove. The insertion of a fresh filling has always required putting the last out of operation. and as a consequence loss of time has resulted.

The present invention permits to eliminate the above disadvantages. In accordance with the invention, the groove which is provided in the last and in the present case has the simplest possible shape, e. g. a rectangular shape, has forced therein a removable resilient filling member, which preferably is made of vulcanized rubber and is provided with retaining elements of steel sheet material, engaging in the sides of the resilient filling member, more particularly in places where the periphery of the last forms an are having its center outside of the last. The retaining elements prevent the resilient member from sliding spontaneously out of the groove, while on the other hand permitting easy removal of the resilient member when the latter has become worn out. The ends of the resilient member are retained, for instance, by means of prongs projecting from the bottom of the groove.

Several embodiments of the invention are shown by way of example in the accompanying drawing, in which Fig. 1 is a partial section through the last along the line A-A of Fig. 2;

Fig. 2 is a view of the underside of the last, partially in section through the groove;

Fig. 3 shows a resilient filling member provided with a single retaining element;

f2 Claims. (01. 1s-'-46) Fig. 4 shows a resilient filling member provided with U-shaped retaining elements;

Fig. 5 shows a resilient filling member provided with angle shaped retaining elements;

Fig. 6 shows a resilient filling member having retaining elements on its sides only; and Fig. '7 shows a resilient filling member with button-like retaining elements.

As shown in Fig. 1, a filling member 2! of vulcanized rubber mixture, e. g. a silicone mixture, is inserted into the groove 5 of the last I. The resilient filling member 2 is secured in the groove by means of retaining elements 3 engaging in the resilient member mainly in portions, such as the bend, where the contour of the last forms an are having its center outside of the last. In this way the resilient filling member is prevented from sliding out of the groove in places where this member has the tendency to straighten its curved part. The ends of the filling member are secured by retaining them on prongs 4 which project from the bottom of the groove in the last.

When the resilient filling member 2 has been inserted into the groove 5 of the last I the retaining element 3 penetrates with its ends in the rubber mass, but at the same time it is spread by the rubber mass against the groove walls. In this way sufficient friction is produced in the areas of contact between the filling member and the walls of the groove 5, the friction thus produced preventing the filling member from sliding out of the groove.

This method of securing a resilient filling member in the groove of a last for pressing may be used in connection with both one-piece lasts and divided lasts.

A resilient filling member which has become deteriorated due to the long lasting action of heat may be replaced by the operator himself without any assistance and without interruptin the working process. The replacement does not take more than about one minute so that practically no delay takes place.

The retaining elements may have various constructions and shapes, e. g. may be shaped as shown in Figs. 3 to '7 of the drawings, depending on the locations where they are to be used, and also depending on the flexible and resilient filling material used in each particular case.

What I claim is:

1. In a vulcanization last adapted for the manufacture of footwear and having an elastic interchangeable cutting strip in the side thereof, said last provided with an endless groove of rectangular cross section in the side thereof, a removable provided elastic cutting strip of rectangular cross section seated in said groove under compression between the side walls thereof, a plurality of channel shaped metallic retainer elements disposed along a portion of the length of and embracing the 5 bottom and sides of said cutting strip between' the ends thereof and seated in said groove with the side walls thereof frictionally engaging the side Walls of said groove and retained in gripping relation with the sides of said cutting strip by 1 thereof, said last provided with an endless groove of rectangular cross section in the side thereof extending around the toe and heel portions and along the intermediate concavely curved portions thereof, a removable elastic cutting strip of rectangular cross section seated in said groove under compression between the side walls thereof and extending throughout the length thereof, a plurality of channel shaped metallic retainer elements disposed along the portions of the length of said cutting strip occupying the portion of the groove along the concavely curved portions of the last and embracing the bottom and sides of said cutting strip and seated in said groove with the side walls thereof frictionally'engaging the side walls of the groove, the longitudinal edges of the side walls of said channel shaped retainer ele- V ments having inturned flanges retained in gripping relation with the sides of said cutting strip by the compression thereof between the sides of said groove. v

MASEK, JOSEF.

. 9 REFERENCES CITED The following references are of record in the file of this patent: V

UNITED STATES PATENTS v Number Name Date 884,218 Schwarz 'Apr., 7, ,1908 1,148,337 Schmidt July 27,1915 1,601,335 Addison Sept. 28, 1926 1,842,719 Dunker -..;J an. 26, 1932 2,103,062

Images