Abstract: An actuator for a press comprises a piston disposed through a small bore diameter high speed actuating cylinder, having a piston head disposed within the actuating cylinder and another piston head disposed within a larger bore diameter hydraulic clamping cylinder to apply the required clamping force to the press.

Abstract: An actuator for a press comprises a piston disposed through a small bore diameter high speed actuating cylinder, having a piston head disposed within the actuating cylinder and another piston head disposed within a larger bore diameter hydraulic clamping cylinder to apply the required clamping force to the press.

Abstract: A tandem press has a moving frame comprising a moving platen moving in a reciprocating motion between stationary outer platens, between a first clamping position in which the moving platen clamps a first mold mounted on one side of the press, and a second clamping position in which the moving platen clamps a second mold on the other side of the press. The tandem press of the invention thus provides two complete clamping cycles within one press cycle. In the preferred embodiment the hydraulic pistons actuating the moving platen also serve as guide bars for maintaining the moving platen in alignment with the stationary platens. In the preferred embodiment the actuating cylinders are small bore diameter high speed cylinders, and the moving platen is provided with larger bore diameter hydraulic clamping cylinders to apply the required clamping force to the mold after the actuating cylinders have moved the moving platen to the clamping position.