GB778466A - Method of, and apparatus for, producing hollow metal parts by extrusion - Google Patents

Abstract

778,466. Extruding. BIGINELLI, O. F. A. Nov. 1, 1955 [Nov. 24, 1954], No. 31183/55. Class 83 (4). In the production by extrusion of a hollow metal body, such as a case, a metal billet 32 is placed on an extrusion plunger 11 having means for locating the billet thereon, and the plunger is then raised to force the billet into a container 1, having a closed upper end, and backwardly extrude the billet over the plunger to form the container 35, Fig. 4 (not shown). The plunger 11 has a central protuberance 31 which engages in a central depression on the billet; the plunger is secured by an annular member 20 to a lower movable element 15 of the extrusion press. A coolant is circulated through a passage 26a and through a tube 27 within the plunger 11 and is returned along the outside of the tube to a discharge passage 30. The head 12 of the plunger is of larger diameter than the shank 11 and the bore 5, 7 on the container 1 is stepped whereby a clearance is provided between the wall of the extruded case and the plunger and container, Fig. 3 (not shown), thus reducing the required extrusion pressure. The container 1 is secured to an upper movable element 3 of the press and contains an ejector 10 for removing the finished case. Both the plunger 11 and the container 1 move towards each other during the extrusion stroke and a peripheral surface 4 on the container engages an inner surface 23<SP>1</SP> on the annular member 20 for positively locating the container and plunger relatively to each other. The annular member 20 is non-rotatably secured to a support 14 by a nut 26 with an interposed packing 21.