GB753506A - An improved combined billet-piercing and extrusion press - Google Patents

Abstract

753,506. Extruding j billet - piercing. SCHLOEMANN AKT.-GES. Sept. 25, 1953 [Oct. 14, 1952], No. 26432/53. Class 83 (4). An extrusion press, particularly for making hollow bodies 16 open at one end, has a piston 8 operating the extrusion ram 3, a piston 6 operating a billetpiercing mandrel 2 and an auxiliary piston 11 which assists the piston 6 during the piercing operation, the three pistons being disposed co-axially. The piston 11 carries a cross-head 12 which transmits pressure to a cross-head 5, carried by the piston 6, through rods 13. An adjustable stop 14 limits the forward movement of the auxiliary piston. The supply of pressure fluid to the pistons 6 and 11 may be controlled by a single lever and the supply to the auxiliary piston 11 may be shut off automatically when the crosshead 12 strikes the stop 14. After piercing the billet, the mandrel is moved forwardly during the extrusion by the piston 6 only. A U-shaped stripper 16 operated by a piston in a cylinder 17 severs the workpiece 15 from the discard remaining in the extrusion die 1, and holds back the workpiece during the withdrawal of the mandrel. The stripper may be controlled automatically by a switch actuated by the cross-head 5. Withdrawing cylinders are provided for the ram and mandrel. The end of the return movement of the ram and mandrel may be cushioned by a buffer or by throttling the escape of pressure-fluid from the cylinders of the pistons 6, 8, 11 or by admitting pressure fluid to the opposite ends of these cylinders. In an alternative embodiment two of the pistons may be disposed coaxially one within the other.