Patent ID: 7371064
Filing Date: 2008-05-13
Classification: B29C

Abstract:
1. A hydraulic device for back and forth movement as well as locking of a machine part, in particular for opening, closing and clamping half-molds of an injection molding tool of an injection molding machine, comprising: a cylinder having a first pressure space with a pressure medium: a primary piston which includes one or more piston rods and is constructed to float in the pressure medium in the first pressure space, a one of the one or more piston rods being connected to a platen for a half-mold of an injection molding machine; and a secondary piston axially movable in the cylinder and sized to bound the first pressure space on one side thereof in any axial disposition thereof, said secondary piston having a recess in which one of the one or more piston rods of the primary piston is movable, said primary and secondary pistons having opposing sides to define confronting contact surfaces which contact one another when the half-molds are clamped.