Multiple-cylinder extrusion press

An extruding press comprising:

• a housing defining an axis;
• an end frame displaceable axially on the housing;
• a plurality of cylinders on the housing;
• respective pistons having axially oppositely directed front and rear faces and subdividing the cylinders into front and rear compartments;
• respective piston rods extending from the pistons axially forward through the respective rear compartments out of the respective cylinders and connected to the end frame;
• a tool fixed on the housing;
• means for positioning a workpiece between the tool and the end frame;
• means for pressurizing the front compartments and thereby axially rearwardly displacing the end frame and pressing the workpiece rearward against the tool;
• respective fluid-powered actuators braced between the housing and the pistons;
• means for pressurizing the actuators and thereby displacing the end frame forward away from the tool;
• means including passages extending between the compartments and controllable valves in the passages for permitting free fluid flow between the compartments;
• respective filler bodies projecting rearward from the rear faces through the respective front compartments out of the respective cylinders and each reducing an effective surface area of the respective rear face so that it is generally equal to an effective surface area of the front face of the respective piston;
• respective axially movable partitions in the front compartments forming therein a front subcompartment;
• and
• means for pressurizing the front subcompartment with a gas.