Valve patch applicable to hollow rubber articles - comprising a main body, a protectively coated seat, and a screw threaded tube

摘要

A valve patch that may be applied to a hollow rubber article comprises a main body made of rubber; a flat patch plate fitted to the base of the main body and having a protective coating; and a screw-threaded tube which is partly surrounded by a rubber shaft and connected with the surface of the patch plate. Mfr. comprises introducing a suitably coated patch plate into a recess of a mould, together with the screw-threaded tube and a vulcanisable rubber mixt. for the shaft; vulcanising under pressure and with heating and thereby bonding the several components together. the patch plate is specif. completely shaped before placed into the mould, and also coated with an additional adhesive coating for the shaft. The introduction of the vulcanisable mixture for the shaft, into the mould, is effected by injection or transfer-moulding onto the adhesive coating of the patch plate and around the screw-threaded tube. Substantial speed-up of prodn. rate is obtd. with accurately shaped mouldings, even when the patch plate has a relatively complex configuration e.g. with tooth-edged main body.