GB840270A - Improvements in extrusion presses - Google Patents

Abstract

840,270. Extruding. SCHLOEMANN A.G. Nov. 12, 1957 [Nov. 28, 1956], No. 35190/57. Class 83 (4). An extrusion press for forming hollow products has a piercing mandrel 40, a press ram 37 carried by a cross-head 20, a longitudinally displaceable billet container 4 connected rigidly with a sliding cross-bar 21 arranged behind the crosshead, and an alignment surface 21a on, or secured to, the cross-bar 21 adapted to be pressed against an alignment surface 20a on the cross-head for aligning the container with the press ram. The container 4 is mounted in a holder 14 connected by rods 17, 19 with the cross-bar 21 which is moved forwardly by plungers 24 in hydraulic cylinders 26 and is retracted by plungers 30 in hydraulic cylinders 31 which plungers act on cross-heads 29 connected by rods 27 with the cross-bar 21. Ram 37 is secured to the main press plunger 32 located in the cross-head 20 and working in a main cylinder 8. The ram is retracted by plungers 35 working in cylinders 36. Piercing mandrel 40 may be rigid with the ram or may be driven relatively thereto by a separate hydraulic motor. Before extrusion begins pressure is admitted to cylinders 36 to slightly retract the cross-head 20 and then to cylinders 26 to advance the cross-bar 21 whereby the alignment surfaces 20a, 21a are pressed together and, due to the larger area of pistons 24, both the cross-bar and cross-head are moved to the left to press the container 4 against the bolster 1 and extrusion die 3. In another embodiment, Figs. 6-12 (not shown), the cross-bar is located behind the main cylinder and is connected with the container holder by rods having shoulders forming an alignment surface which contacts the alignment surface of the cross-head. The press may be horizontal or vertical.