GB1259794A - Improvements in or relating to extrusion presses - Google Patents

Abstract

1,259,794. Extruding. ALCAN RESEARCH & DEVELOPMENT Ltd. 1 May, 1969 [3 June, 1968], No. 22377/69. Heading B3P. An extrusion press includes a die 12 composed of a major die 30 with a die aperture 31 and a recess 34 on its outlet side for a minor die 35 and an adjustable bolster 24, Fig. 8, with gates 70, 71 to back the die 12 and releasably hold the minor die to allow it to move with the extruded product after the first portion of the billet has been extruded so that the extruded product has a first portion extruded through the minor die and a second portion extruded through the major die. The gates 70, 71, Fig. 4, are guided for movement between plates 56, 57 screwed to an apertured disc 50. Each gate has a threaded sleeve 74-77 at its vertical edges engaged by threaded rods 78, 82. The threads are such that rotation of the rods either moves both gates away or towards the press axis. The upper end of one rod 82 is rotated by a driven shaft (96), Fig. 7 (not shown), when it is desired to release the minor die. The other rod 78 is driven by chain 89 and sprocket 88 from the rod 82. The bolster and the die 12 are held in a tool container and backed up by sub-bolsters 25. The tool container (11), Fig. 1 (not shown), is held against the billet container 10 by a gate lock (29) which permits insertion and removal of the tool container through the platen (14). The press ram (19) is operated mechanically or hydraulically. In operation the tool container (11) is loaded with the die 12, the adjustable bolster 24 and the sub-bolsters 25 outside the press and inserted axially through the platen (14). An aluminium billet (17) is pressurized in the container 10 to extrude it through the minor die 35, Fig. 8. When the required length (45), Fig. 3 (not shown), has been extruded the pressure is relieved, the ram retracted slightly and the billet container 10 moved slightly away from the die. The gates 70, 71 are opened sufficiently to allow the minor die 35 to pass between them and the extrusion pressure applied. The billet is extruded through the major die and the extruded product carries the segments 38 of the minor die, Fig. 9. The butt end of the billet is sheared-off after extrusion. In an alternative embodiment, Figs. 10, 11 (not shown), the die and the adjustable bolster are arranged on the die slide of a die slide press.