GB737143A - Method of and apparatus for the production of shell moulds - Google Patents

Abstract

737,143. Moulding-machines. DEUTSCHE EDELSTAHLWERKE AKT.-GES. June 22, 1953 [June 30, 1952], No. 17300/53. Class 83 (1). In a shell-moulding process, patterns preheated by travelling through an oven are successively brought into operative engagement with at least one pressure head, to which moulding material is delivered by compressed air and discharged to the pattern and the excess material is removed by tipping the pattern relatively to the pressure head. Patterns 4 are moved through an oven 1 by a turnstile 2 to the discharge opening 3 where a parting-medium is applied and an intermediate frame 5 fitted. The frame is connected to the piston-rod of a cylinder 6 operable to position the frame and pattern beneath pressure heads 9, which are then lowered and the sand-resin mix blown onto the pattern by low-pressure compressed air. After blowing, the pressure heads are raised and the pattern rotated through 360 degrees by a turnover mechanism 10, surplus mix falling on to a shoot 11 and returning to a pressure-container 15. The pattern is then moved back through the oven to cure the mould. The pressure heads and conduits conveying the mix are preferably made of an elastic material such as rubber. In a modification, Figs. 3 and 4, a fully automatic machine comprises a circular oven 18 through which are moved patterns on arms 20 and which has a segmental recess 22 in which are three stations. At the first station 23 a pattern plate is rotated through 180 degrees and a previously-formed and cured mould ejected by ejector pins in the pattern actuated by a press 24, the mould falling on to a conveyer 25, preferably of rubber. Still in the inverted position the pattern moves to the second station 26 over a suction device which removes adhering material. The pattern is then coated with a parting medium, and rotated back through 180 degrees as it travels to the third station 29, where pressure heads 30 and a frame 31 are positioned on the pattern. Valves in the pressure containers 33 and the supply from a collecting hopper 34 are thereby actuated and the mix blown. The pressure heads are raised, the pattern rocked to return excess mix to the containers 33, the frame 31 lifted by a linkage 36 and the pattern-plate and adhering mould moved through the oven for curing. The apparatus is controlled by mechanical and electrical devices, or hydraulic or pneumatic devices.