Abstract: A detachable coupling provided between the helix and drive shaft of an injection molding machine is provided by a flattened end of the helix shaft received within a fork-shaped end of the actuation shaft so that respective boreholes are aligned for receiving therethrough a pin. An axially slidable locking sleeve is movable between a position preventing movement of the pin and a position permitting removal of the pin, and a resiliently urged locking detent ball and groove are provided at each of the positions.

Abstract: A fluid pressure actuated drive for providing for the closing unit of an injection moulding machine a to and fro traversing motion of a movable part of the unit with little force and a clamping of the closed unit with a greater force. The device has at least two double acting piston and cylinder devices which act in parallel and the pistons of which each have at each side a piston rod which passes through a seal in the responsive adjacent cylinder end. The piston rod on one side of at least one piston is thicker than that on its other side and the piston rod on one side, which corresponds to the same working side as one side of the one piston, of the or each other piston is thinner than that on its other side. Traverse in one direction is provided by applying fluid pressure to both sides of the one piston, and in the other direction by providing fluid pressure to both sides of the other piston. Clamping pressure is provided by applying fluid pressure to one side only of each of the pistons.