HOT SPRUE SLEEVE VALVE ASSEMBLY FOR AN INJECTION MOLDING MACHINE

摘要

A device for injection moulding centrally apertured recording discs includes a hot sprue assembly which has a heated bushing (54). The apparatus has a central flow passage leading to a radial flow passage defined between its lower end and a dispersion(66) carried thereby. A valve sleeve located about the bushing is normally biased to a position where its lower edge engages the surface of the dispersion head to block the radial flow passage. The injection pressure is such that the sleeve is faced upwardly against its bias to open the flow passage for injection.