GB683751A - Improvements in or relating to die or press casting machines - Google Patents

Abstract

683,751. Casting- machines. SAUTER, H., and HAHN, W., (trading as HAHN & KOLB). April 12, 1951 [May 4, 1950], No. 8512/51. Class 83 (i). A die-casting machine comprises a piston serving to force molten metal from an unheated pressure chamber into one or more dies laterally connected therewith and also to eject the residue and a counter-piston serving as the base of the chamber and also as a rotary valve controlling the passage or passages leading to the die or dies. A chamber 10 communicates by a passage 16 with a die comprising a fixed part 40 and a movable part 39 carried at the end of a hydraulic piston 38. The bottom of the container is normally closed by a counterpiston 11 supported in an extension of a hydraulic piston 41 so that it may be rotated by an integral projecting lever 12. When in its upper position the piston 11 closes the passage 16 unless rotated so that a slot 15 in the upper end is in communication with the passage. This rotation may be effected against a spring 13 by an auxiliary piston 9. The piston or plunger 5 may be moved down into the container by pressure from a hydraulic accumulator 1. In operation, pressure fluid from a pipe 17 passes by a control valve 30 to raise the plunger 5 and retract the piston 9 and by another valve 31 to press the die parts together and raise the piston 41 so that the counter-piston 11 closes the passage 16. Molten metal is then poured into the chamber 10 and the valve 30 operated so that pipe 22 is connected to exhaust and the plunger 5 descends under the pressure of the accumulator, connected by a pipe 6 to the piston 9 which is moved outwards to turn the arm 12. By means of a throttle valve 7 it is arranged that the opening of the passage 16 occurs just before the plunger reaches the surface of the metal, which is then forced into the die. After solidification of the metal the valve 31 is operated to exhaust pressure fluid from the spaces 34, 35 and supply it to spaces 44, 45, the surfaces of the pistons 38, 41 exposed to such fluid being such that the piston 41 moves down first, aided by the pressure exerted by the plunger 5 which severs and ejects the residue from the chamber. Piston 38 then moves to open the die. Valves 30, 31 are again operated to return the parts for another casting operation.