Internally-grooved rim moulded on a thermoplastic pipe - using a mould core that shapes part of the rim, as well as the groove

摘要

A socket is moulded on to the end of a softened thermoplastic pipe by dilating it over a profiled arbor under pressure, additional material being moulded on at the same time. The mould shapes the extreme end of the added material into a thickened rim with an internal groove. The groove is shaped by retractable segments mounted on the arbor, and the finished pipe has its greatest dia. at the rim, opposite the groove. To allow the mould to be opened conveniently, the invention provides that the end of the pipe rim, beyond the largest dia., is to be shaped by a profiled collar, mounted on the arbor, and moving with it.