Patent ID: 9333691
Filing Date: 2016-05-10
CPC Classification: B29C

Claim Text:
1. A clamp assembly for an injection molding machine, comprising: a) a cylinder housing having an inner end and an outer end spaced axially apart from the inner end; b) a piston assembly comprising a piston head affixed to an end portion of a tie bar, the piston assembly slidable within the housing between a meshing position in which interference-free movement of a toothed lock member between locked and unlocked conditions relative to a toothed portion of the tie bar is accommodated, and a clamped position in which a clamp force is exerted by the tie bar across a mold of the injection molding machine, the clamped position spaced axially apart from the meshing position; c) a clamp chamber axially intermediate the piston head and the inner end of the housing for holding pressurized fluid and urging the piston assembly to the clamped position when pressurized; d) a spring return device axially intermediate the piston assembly and the outer end of the housing, the spring return device accommodating movement of the piston assembly from the meshing position to the clamped position when the clamp chamber is pressurized, the spring return device having a return device engagement surface pushing the piston assembly back to the meshing position when pressure in the clamp chamber is relieved; and e) a stop fixed relative to the housing, the spring return device having a catch spaced apart from the stop when the piston assembly is in the clamped position, and when the return device engagement surface has pushed the piston assembly into the meshing position the catch abuts the stop to limit further axial travel of the return device engagement surface.