GB1388019A - Die-casting machine - Google Patents

Abstract

1388019 Pressure die casting machines IDRA-PRESSEN GmbH 18 April 1972 [29 April 1971] 17990/72 Heading B3F A cold-chamber die casting machine in which metal is forced into the mould in phases comprises a multiplier 1, a pressure reservoir 7 connected to the multiplier via a blocking piston 13, and a 4/2-way valve 6 which controls a shut off valve 5 in a line 10, 9, 8 connecting a space 11 in front of the blocking piston to a space in front of the pressure reservoir 7. During the first phase, fluid pressure from a pump P is supplied to a bore 3 in the multiplier piston 1 and acts on the press piston 4 to cause a relatively slow movement thereof. After a given time or after the piston 4 has reached a given position, the valves 6 and 12 are actuated. Operation of the valve 6 actuates the shut off valve 5 to permit pressure medium from the reservoir 7 to flow to the space 11. The increased pressure now acting on the piston 4 causes the piston 4 to move more rapidly during the second phase of the metal injection process. The speed may be controlled by adjustment of a spindle 34. When the mould has been filled, the pressure in the space 11 rises and causes a valve 15 to change over. This opens the space 16 to atmospheric pressure, this permitting the blocking piston 13 to move to the right and the pressure fluid in the reservoir 7 to act directly on the multiplier piston 1 which begins to move to the left as soon as the counter-pressure in the space 20 has been overcome. In another embodiment the valve 5 is combined with the blocking piston 13 and in a further embodiment the valve 12 is omitted, its function being carried out by the valve 6.