GB803909A - Improvements relating to shell moulds for casting metals - Google Patents

Abstract

803,909. Molding-processes. GENERAL MOTORS CORPORATION. April 1, 1957 [April 20, 1956], No. 10534/57. Class 83 (1). A reinforced shell mould section comprises a mould half, to the back of which is detachably secured a flask having a wall separated from the back of the mould half by a space packed with a refractory comminuted material such as sand. The shell half 14, Fig. 1, is made by blowing mix on to a heated pattern plate 10 carried on a vertically movable table 12. The shell may then be compressed by an electrically-heated press head 64, Fig. 3. The pattern and shell assembly, which includes a frame member 18, is then positioned beneath a flask 68, Fig. 4, spring-loaded clamps 90 thereon engaging the frame 18, and green sand is blown into the cavity 80 beneath the flask and the shell from a magazine 70. The shell and flask assembly is then stripped from the pattern by pins 50. An automatic or semi-automatic apparatus, Fig. 6, comprises a runway on which are movable a sand-resin blowhead and magazine assembly 114, an electrically-heated pressure head 116, and a green-sand blowhead and magazine assembly 118, which are located in turn over the pattern table 121. Hoppers 130, 132 containing green sand, and sand-resin mix respectively, are located at opposite ends of the runway. The green-sand blowhead 118 comprises arms 148 which hold the reinforced mould-section after stripping from the pattern, and deposit it on a conveyer 142. After casting, the flasks may be returned on the conveyer and removed therefrom, in the arms 148, to the moulding- machine.