Patent GB-500693-A (GB)
Title: Hydraulic controlling device in machines for die casting metal under pressure
IPC: B22D17/32
Filed: 1938-05-26
Abstract: 500,693. Casting-machines. INJECTA AKT.-GES. May 26, 1938, No. 15721. Convention date, May 29, 1937. [Class 83 (i)] Clamping moulds: castings, extracting.- A hydraulic control device for pressure casting - machines having an oscillating cam shaft 19, for operating in proper sequence the valves controlling the closing and opening of the mould, the extraction of cores and the ejection of the casting, is provided with an automatic reversing gear for operating said shaft. Pressure fluid is supplied from a pipe 2 constantly to pistons 16 for pushing off the mould half 14 from the metal injecting jet, and to the smaller sides of differential pistons 9, 112, and 43, used respectively for knocking. off the casting, for forcing the molten metal, and for rotating the shaft 19. Hand-operated valves 20, 21 admit this fluid also to a pressure conduit 27 and to a valve 26<1> which, when opened by a cam 82<1>, admits it to the larger side of the piston 43 which can however be opened to exhaust by the valve 26<11> or by a hand-operated valve 23<1> when the valves 20, 21 are closed. A pinion 42, mounted on the shaft 19, is engaged by a rack 41 connected to the piston 43. Cams 59 on the shaft operate valves 28, 30<1>, 32<1>, 331 to connect the conduit 27 when required to buffer pistons 62, pressuremultiplying piston 31, the larger side of the knock off piston 9, mould-closing piston 5<1>, and metal-forcing piston 112. A cam 59<1> operates valves 6, 7 to connect the smaller side of the piston 5<1> and, if a valve 79 is open, a fluid link 77 to pressure through pipe 4 and hand valve 3 or to the exhaust conduit 34 ; When the valves 26<1>, 30<1>, 32<1> and 33<1> are closed valves 26<11>, 30<11>, 32<111> and 33<111> are opened and connect the parts, previously supplied, to the exhaust conduit 34. A non- return valve 32<11> prevents the high pressure fluid from piston 31 from flowing to conduit 27 instead of to the piston 5<1>. The double cam 82<1>, which determines the direction of rotation of the shaft 19, is loose thereon but has lateral pins 88<1>, 88<2>, Fig. 6, which project into circular slots, in cams 81, 81<2> keyed on the shaft 19, containing stops 86, Fig. 2, pressed apart by springs 87<1>, 87<2>. When fluid pressure is admitted to the system, by operating the valve mechanism 22, Fig. 1, it passes valve 26<1> to the top of piston 43 which rotates the shaft in a counterclockwise direction. The cam 82<1> with its pins 88<1>, 88<2>, is prevented fromrofating therewith by a pawl 84, Fig. 2, and the stop 86, when it reaches the pin 88<1>, is arrested and the spring 87<1> is compressed until the cam 81<1> engage a roller 84a and thus lifts the pawl 84<1> and releases the cam 821 which is rapidly rotating by the spring 87<1> into its other position as determined by a spring stop 89, whereby the valves 26<1>, 26<11> and the rotation of the shaft 19 are reversed. A similar action by another pawl, another stop, the pin 88<2>, and spring 87<2>, returns the valves 26<1>, 26<11> to the position shown in Fig. 1, and the shaft 19 and cams 59 &c. are again rotated in the original direction. The speed of rotation of the shaft is controlled by adjustable valves 45, 46.