Plastics injection blow-moulded pipe coupling - has bushing with groove for ring seal, the groove having angular flanks

摘要

Plastics injection blow-moulding, e.g. a pipe fitting, has coupling sleeve with an annular groove adapted to receive a ring seal. The transitional zone from sleeve to trailing flank of the groove is relatively sharp-edged; or the transitional zones from the sleeve to both leading and trailing flanks of the groove are shaped. In the mfr., a beading protruding inwards is applied at the transitional zone of the moulding, which is drawn into its final position during the blow-moulding oif the groove.