Pneumatische Steuervorrichtung für Heißkanalnadelventile für Spritzgießwerkzeuge

摘要

Pneumatic control device for hot runner needle valves for injection moulds, which control device comprises a control piston (1), bearing the valve needle (10), a control cylinder (2) receiving the control piston, and a cylinder-receiving element (3), receiving the control cylinder. The control cylinder (2) is provided with compressed-gas channels (25a, 25b) for feeding and removing compressed gas to and from the cylinder chambers (4a, 4b) separated by the control piston. According to the invention, the control cylinder (2) can be pressed by one of its end faces (21) via seals (26a to 26c) against a contact surface (32) of the cylinder-receiving element (3), the seals (26a to 26c) bounding two mutually separate channel chambers (28a, 28b). The control cylinder (2) is displaceable on the contact surface (32) perpendicularly with respect to the piston longitudinal axis (b). Into each channel chamber (28a, 28b) there opens out a compressed-gas line (33a, 33b), leading through the cylinder-receiving element and for feeding and removal of the compressed gas, and from each channel chamber (28a, 28b) there leads a compressed-gas channel (25a, 25b), running in the axial direction, through the wall of the control cylinder (2) to a cylinder chamber (4a, 4b). The invention makes it possible for constraint-induced transverse forces on the valve needle (10) to be eliminated by the cylinder with the pistons for lateral displacement.