GB550864A - Improvements in or relating to cold chamber die-casting machines for aluminium, brass and the like - Google Patents

Abstract

550,864. Hydraulic presses. DANIELS, Ltd., T. H. & J., and DANIELS, J. L. June 23, 1941, No. 7891. [Class 69 (ii)] [Also in Group XXII] In a die-casting machine of the kind having a cold chamber to receive a charge of molten metal for the die 11, 13 this is opened and closed by a plunger 19 which is connected to the die part 13 by a head 15a, rods 15, and head 14, operates in a fixed cylinder 20 and has a longitudinal bore 22, Fig. 4, in which fits a fixed ram 23 having a longitudinal passage 30 for motive fluid. When pressure fluid is admitted through the passage 30 as it passes through a small passage 38 in a spring-pressed valve 34 into the space 122 thus moving the plunger 19, die part 13, and valve slowly to the left. When the valve 34 uncovers the ports 37 the plunger moves rapidly to close the die, prefiller fluid from a tank 23a passing, through a non-return valve into the space 222 behind the plunger 19. When the die is closed pressure fluid is applied to the space 222 and the molten metal is forced into the die. After casting, pressure fluid is admitted to the space 120 to move the plunger 19 to the right, some of the fluid passing through a gate 19a to open the non- return valve and allow the fluid behind the plunger to return to the tank 23a. When the die is almost fully open the valve 34 is moved to the right to slow down the die-opening movement.