Joining unvulcanised rubber strip butt - by first heating ends then pressing together before releasing

摘要

Unvulcanised or partly prevulcanised rubber strips are butt-jointed using two pairs of grippers holding the strip near its ends. The ends are first heated to at least 100 deg.C by placing a heated plate temporarily between them, the plate is then removed, the grippers are temporarily brought together to press the ends together, and then the grippers are simultaneously opened to release the strip. Pref. the pairs of grippers are accurately profiled to the cross-sectional form of the strip. Internal shells in the grippers to suit different types of strip may be interchangeable. Used esp. for vulcanising of a closed ring or similar closed strip or beading, e.g. for framing of an automobile window, where the cross-section is comparatively complicated. Method enables a firm joint to be produced without any cracking and for different types of rubber mixts.