Abstract: The invention relates to a hydraulic device for the back and forth movement and locking of a machine part, in particular for the opening, closing and locking of an injection molding tool. The hydraulic device comprises a cylinder (1), in which a first pressure space (6) is provided, a primary piston (2) with one or several piston rods (11) which may float in a pressure medium within the first pressure space (6) and furthermore an secondary piston (7) which may be axially displaced within the cylinder (1). The invention is characterized in that the auxiliary piston (7) comprises recesses (12), into which the piston rods (11) of the primary piston (2) can be moved and the opposing sides of the primary piston (2) and secondary piston (7) have surfaces (40, 41) which may be brought into contact. In a first movement phase (opening and closing) only the primary piston (2) is moved.

Abstract: The invention relates to a hydraulic device for the back and forth movement and locking of a machine part, in particular for the opening, closing and locking of an injection molding tool. The hydraulic device comprises a cylinder (1), in which a first pressure space (6) is provided, a primary piston (2) with one or several piston rods (11) which may float in a pressure medium within the first pressure space (6) and furthermore an secondary piston (7) which may be axially displaced within the cylinder (1). The invention is characterized in that the auxiliary piston (7) comprises recesses (12), into which the piston rods (11) of the primary piston (2) can be moved and the opposing sides of the primary piston (2) and secondary piston (7) have surfaces (40, 41) which may be brought into contact. In a first movement phase (opening and closing) only the primary piston (2) is moved.

Abstract: This clamping device (5) is of the type comprising a peg (6) which projects from the half-mold (2) and which is received in a recess (17) in the platen, and a clamping mechanism (5) including a transverse cylinder (9) and a wedge (8) deigned to interact with the peg in order to ensure the removable clamping of the half-mold. The clamping mechanism (5) comprises a bearing block (7) designed to be fixed at the entrance of the recess (17) and including, on the one hand, a passage (25) for the peg (6), and, on the other hand, an incline (24) for the bearing of the wedge (8), this incline being provided on that face of the block which points towards the recess in the platen. The peg (6) is axisymmetric with a widened head (14). The clamping device finds applicability in the injection-molding of plastics.