GB428115A - Method of casting metals - Google Patents

Abstract

428,115. Casting metals under pressure. SCHULTZ, J. A., 3416, West Bancroft, and ZAPF, J. A., 1126, Western Avenue, both in Toledo, Ohio, U.S.A. April 20, 1934, No. 11924. [Class 83 (i)] In a method of casting, particularly for non-ferrous metals, the metal is injected into the mould in a plastic state at a temperature slightly above its melting point at a pressure from 1000-2000 lbs. per square inch, the mould being maintained at a temperature which preferably does not exceed 60 per cent of the temperature of the molten metal. In one example a zinc base non-ferrous alloy having a melting point of 735‹ F. is forced into the die at a temperature of from 750 to 800‹ F., employing a charging pressure of 1600 lbs. per square inch, the die being at a temperature of 375-400‹ F. In one machine for carrying out the method a furnace 15, fed by fuel from a pipe 21, carries a melting-pot 20 supported on an upper closing plate 19. Within the pot is secured a delivery chamber fed through an opening 26 and having a delivery spout 28. A bore of this chamber receives a pressure plunger 30 operated by a piston in a cylinder 33 controlled by an admission valve 84. A stationary die-plate 35 is secured to the delivery chamber by bolts 36 and has legs 39 each carrying a wheel engaging a rail 40, the die plate being thus quickly removable for repairs. The movable member B of the sectional dies is mounted on a plate 45 having bosses 46 which are guided along rods 43. An adjustable link 47 is connected by a ball-joint to the plate 45 and its other end is pivoted to a shaft 50 mounted eccentrically between a pair of gear segments 54 journalled in a subframe 55 and coacting with a double vertical rack 59 which is actuated by a hydraulic cylinder 60 fed from a pump 67 driven by a motor 68. The valve 63 controlling this cylinder is actuated from a hand lever. An extension of the rack is interlocked with the control 78 of the valve 84 so that the plunger 30 cannot be actuated to force metal into the dies unless the dies have previously been closed by the action of the cylinder 60. For this purpose the flatted end of control rod 83 engages a slot in the rack extension, this slot terminating in a circular opening which allows rotation of the rod 83 only when the rack is in its raised position and the dies closed. The subframe 55 and all the parts carried thereby may be adjusted by means of a hand lever 99 and set by spacing members 94 to permit dies of different depth to be used. The accurate setting of the dies is effected by adjusting the two-part link 47. The rack 59 is also adjustably connected to the actuating rod. The temperature of the melting-pot is maintained constant by a pyrometer 120 connected with a temperature selector 126 which controls through a relay the motor 128 connected to the fuel supply valve 130 to regulate the flow of fuel. A byepass 132 permits manual adjustment of the fuel supply. The temperature of the contact surfaces of the dies is controlled by cooling medium conveyed through pipes provided with regulating valves. Rods 146, 148 carry an ejecting plate 154 fitted with a number of pins 156 which automatically eject the casting when the movable die plate is withdrawn.