Abstract: A fixed platen is supported in the machine frame, and a movable platen is connected to two parallel rods which project rearwardly through the fixed platen. Each rod carries a first piston and each piston is slidably received in a first cylinder. These cylinders are slidably received on the rods and each cylinder has a forward end defining a second larger piston slidably received in a fixed second cylinder. The front and rear faces of the smaller pistons are selectively connected to fluid from a first pump through a synchronizing valve, and a paralleling pump supplements the flow from the first pump during synchronization, that is during the major part of the mold opening and closing movement. Slower movement is provided for just prior to the platen reaching the mold open and closed positions.