GB493013A - Apparatus for casting metallic products - Google Patents

Abstract

493,013. Casting. FONDERIE BRUNEAU FRERES. Sept. 16, 1937, No. 25145. Convention date, March 16. [Class 83 (i)] In apparatus for casting metal parts having parallel thin ribs or vanes such as the head H, Fig. 5, of an air-cooled engine, different parts of the mould are made of materials having different heat-conducting characteristics to effect different rates of cooling of different parts, and so prevent cracking &c., the filling of the mould cavity being assisted by external sources of vacuum of different values. To consider the progressive cooling of the cast member, the latter is divided into zones A ... D, Fig. 5. Zone A includes the rocker casings of the valve gear, the metal of these casings being rapidly cooled by forming the corresponding mould parts and core members for the casings of high conductivity material such as bronze. Zone B includes the inlet and exhaust pipes 21 and is cooled more slowly in that the inset parts of pipes 21 are formed by extensions of the main core, Fig. 6, which is of low conductivity such as sand. The zone C, including the cylinder head proper cools still more slowly, being of larger mass and the core also being of sand. The uppermost zone D comprises the heads formed in the pourers and vents and its cooling is reduced as far as possible by sheaths of sand, asbestos or similar material. The cooling thus occurs progressively from zone A to zone D. The ribs of the casting are formed in the inner ends 5, 6 of slidable steel plates 4 which may be heat treated and are guided in grooves in the mould block. These plates are formed with parallel channels 7 open at the outer end and of a depth which may be varied to adjust the suction on the metal forming the ribs. Hoods 11 are secured to each face of the apparatus and are divided into different compartments connected through vacuum ducts 9 to pipes 10 subjected to different degrees of vacuum during the casting. The hoods are fitted with cams 12 which prevent backward movement of the plates 4.