Patent GB-1437435-A (GB)
Title: Centrifugal casting machine and method of casting
IPC: B22D13/10
Filed: 1973-07-27
Abstract: 1437435 Centrifugal casting machines GENERAL ELECTRIC CO 27 July 1973 [4 Aug 1972] 35872/73 Heading B3F A machine for centrifugally casting finned cylinders comprises a plurality of mould sections 21a, 21b, 21c and 21d having interlocking longitudinal edges, means connected to each of the sections for moving them into juxtaposition, means for rotating the mould and means for stripping the mould sections from the cast product. In the embodiment shown the mould 21 is secured to a plate 20 rotated by a motor 19 via belts 29, a shaft 37, a coupling unit 33 and a main shaft 31. A coolant is supplied to and removed from the mould via bores 57 and 64 in the shaft 31 and flexible hoses 62, the coolant being supplied from and returned to annular chambers 53 and 65 respectively surrounding the shaft 31. The mould 21 may be formed of four sections a, b, c and d each of which has a longitudinal edge provided with an orthogonal step 93b. Each mould section is secured to a gripping jaw 86 by bolts 95, each jaw being provided with a bracket 101 which can be detachably secured to a bifurcated member 107 on the end of a piston-rod 102 by pins (110) passing through holes in the bracket 101 and member 107. Each jaw 86 is also provided with a protrusion 100 slidably received in a groove in the plate 20, and two tapered faces 85a and 85b. When locking rings 84a and 84b are moved to the left, as shown in Fig. 1, tapered surfaces 83 on the rings engage the faces 85a and 85b and clamp the mould sections firmly in position. The locking rings are moved by means of pistons 78 via an annular plate 79, a bearing 80, a plate 81 and rods 82, the pistons 78 and plate 79 being movable axially but not rotatable whereas the plate 81 and rods 82 rotate with the mould. The machine is also provided with an assembly 13 comprising a ladle 121 similar to that described in Specification 1,412,199, an expandable arbor 15 similar to that described in Specification 1,403,857, and a lubricant spray head 16, the ladle, arbor and spray head protruding from a post 120 mounted on a turntable (146), Figs. 16 to 19 (not shown), on a carriage 17. The carriage 17 is movable along rails 18 by a piston 166 so that the ladle 121, arbor 15 and spray head 16 may be inserted into the mould. The sequential operation of the machine is illustrated in Fig. 21, the mould sections being moved to and from their assembled position by means of the pulling pistons 102. To ensure correct alignment between the mould sections and the pistons 102 after the metal has been poured and the mould has stopped spinning, a small drive motor 50 is energized to rotate the mould slowly until a protrusion 49 on a plate 40 attached to the shaft 31 is registered with a proximity switch 43. The mould is then locked in this position by advancement of a piston of an hydraulic cylinder 22 into a notch in the plate 20. The rate at which metal is poured into the mould from the ladle 121 is maintained substantially constant throughout the pouring cycle by tilting the ladle at a gradually decreasing rate until about one half of the metal has been discharged and then gradually increasing the rate of tilt until pouring is completed, the rates of tilt at the beginning and end of the pour being equal.