Patent GB-888094-A (GB)
IPC: B22D15/02
Abstract: 888,094. Casting-machines. GENERAL MOTORS CORPORATION. April 12, 1960 [April 30, 1959], No. 13010/60. Class 83 (1). A method of casting a hollow member comprises placing an assembled composite core within a composite assembled mould, casting, dismantling the mould after solidification and removing the casting from between the mould members while simultaneously commencing the withdrawal of the core from the casting. Moulds 12 for pistons are mounted in pairs on a turntable 10. Core inserting and extracting devices or stackers 36 are mounted in pairs rotatable about and vertically movable on a support 40, and each comprises a crosshead 86 vertically movable by a driven screw 74 and carrying the collapsible centre section 102 of the composite core 60, and support members 120 for the core side sections 104, 106. The centre section 102, Fig. 5, is made up of a middle part 108 and side portions 110, 112, whose movement downwardly of the inclined surfaces of the part 108 collapses the centre section 102 for withdrawal. The side portions 110, 112, are urged downwardly by spring-loaded pins 115 when the centre section is held in the crosshead 86 by a spring-loaded pawl 170 actuated through a lever 174 by a cam surface on the mould section 14. Each support member 120 carrying a side core section 104, 106, is supported on parallel links 126, 128, the core section being locked thereto by a spring-loaded pawl 194<SP>1</SP>, Figs. 4, 9, actuated by a cam surface on the mould section 16. In operation, a pair of core stackers 36 are positioned over a pair of open moulds 12 and lowered to position cores between the mould halves, which may include gudgeon pin opening cores. Closing of the moulds actuates the pawls 170, 194<SP>1</SP>, to release the cores from the stackers which are then raised and the mould table indexed to bring the assembled moulds, which may be heated and cooled, to the pouring station 28, the table revolution being then completed to bring the solidified casting beneath the core stackers 36, which descend into engagement with the cores. The mould halves then open locking the cores to their respective stackers. The crosshead 86 of each stacker then commences to rise, collapsing the cores as the stacker itself rises. The initial movement of the crosshead collapses the centre core section 102 and withdraws it from the side sections 104, 106. Further movement of the crosshead engages a cam surface 156 thereon with the link 126 of the support 120 for the side section 104, causing this to move laterally inwardly to clear the casting. A pin 162, Fig. 9, on the crosshead then engages a stop 164 in the member 120 to cause it and the core section 104 to travel upwardly with the crosshead. The can surface 156 then engages the link 126<SP>1</SP> of the support 120 for the side section 106 to move it laterally inwardly, the cast piston clinging to it. The core stacker has meanwhile been indexed through 90 degrees, and the abovementioned lateral movement of the side section 106 is made after the core stacker has been lowered to position, each piston beside an abutment 208 which the lateral movement of the section 106 causes it to strike and fall free into a collection channel 210. The core stackers then rise and are indexed a further 90 degrees to bring the second pair into alignment above the moulds into which fresh cores are deposited for another cycle.