Method of joining waterproof sheets, and their joint structure

Abstract

A method of joining narrow waterproof sheets to obtain a waterproof sheet of wide width having a gently curved joint which is free from any acutely stepped portion. It comprises disposing a cure tape between the overlapping edge portions of the sheets to be joined, positioning a piece of cushiony material below or above the overlapping edge portions, and heating the overlapping edge portions and the cure tape under pressure. The cure tape has a width which is substantially equal to that of the overlapping edge portions before pressure is applied thereto. When pressure is applied, the cure tape projects in opposite directions beyond the extremities of the overlapping edge portions. One form of the joint thus formed is flat on one surface and gently curved on the other surface, while another form is gently curved on both surfaces thereof.

Dependencies are inferred from the claim text.