Hot runner manifold bushing

Abstract

The present invention relates to an apparatus for injecting molten plastic material. The apparatus includes a novel bushing arrangement have a threaded portion which forms part of a mechanical connection between the bushing and an air piston housing so as to reduce the possibility of plastic material leaking between the bushing and the air piston housing. The bushing has a melt channel for mating with a melt channel in a manifold in which the bushing is housed and with an axial channel in a nozzle body. The bushing is sized to fit within a bore in the manifold so as to reduce the possibility of leakage between the bushing and the manifold. The bushing also serves to close off or plug holes or channels drilled into the manifold. In one embodiment of the present invention, the bushing has a passageway through which a valve stem for closing off a gate in the nozzle body passes.

Dependencies are inferred from the claim text.