Abstract: A process for forming a strong, pressure-tight joint between fabric substrates includes coating each substrate with polyurethane on one side, superimposing the fabric substrates so that the polyurethane layers are together, welding elongated regions of the polyurethane together under heat and pressure and sewing through the weld. The edge is then folded over and bonded to itself and the material is spread out. The resulting material can be bonded to a sole to form a waterproof, lightweight boot.

Abstract: A seam interconnection to relatively thick material parts such as leather parts of shoes comprises parts which have edges which are aligned and have one surface such as the interiors or skin side surface of the leather which is formed with a groove extending along its height which is substantially parallel to and spaced inwardly from its associated edge. The two parts to be joined are aligned back to back with their outer or grain sides engaged and a threaded seam is made to hold the two parts together by placing the seam in the grooves of the respective parts. The parts are then formed to a desired shape, for example, are curved so as to form them into a heel and in so doing, the marginal area adjacent the edge is bent backwardly upon itself so that the overlying part extends into the groove. When a heel portion of a shoe is formed the curved configuration of each part is made so as to complement the configuration of the overlying parts resting in the groove so that an irregular surface is avoided.

Abstract: Cooperating top and bottom die assemblies for use in a press to fold the edges of a non-rigid workpiece. The top die comprises a horizontal support plate having a radiused folding plate affixed to its underside. A spring biased stripper in association with the support plate is shiftable vertically relative thereto between a retracted position and a normal extended position below the radiused folding plate. The top die assembly support plate has a plurality of upstanding support posts on its upper surface together with means to affix the top die assembly to the upper platen of the press with the free ends of the upstanding support posts in abutment thereagainst. The bottom die assembly comprises a horizontal base plate adapted to rest on the bottom platen of the press. The base plate has a first set of downwardly depending hollow posts mounted on its underside to either side of the press bottom platen.

Abstract: An apparatus for folding and sealing the edges of a non-rigid work piece and a method of performing folding and sealing operations therewith. The apparatus comprises a press with a main cylinder, at least one auxiliary cylinder and upper and lower die assemblies for the press. The upper die assembly comprises a folding cavity plate operatively connected to the main cylinder and having a folding cavity with an electrode surrounding a part at least of the cavity. A stripper in association with the upper die assembly is independently shiftable by the at least one auxiliary cylinder between a retracted position above the folding cavity and an extended position therebelow. The bottom die assembly comprises a plate having a female cavity therein of a size and shape equivalent to that of the folded work piece and a male plug receivable within the female cavity with close tolerance.