GB931174A - Method for centrifugal casting and apparatuses for practising it - Google Patents

Abstract

931,174. Centrifugal casting-machines. F. TRINDLER. May 10, 1961 [May 11, 1960], No. 16977/61. Class 83 (1). In a method of centrifugal casting, the cast article after it has set sufficiently to allow the mould to be opened, is carried away in one mould part, and an identical mould part is assembled with the rest of the mould to form a complete mould ready for casting another article. A desired number of lower mould parts 40, 40<SP>1</SP>, Figs. 3, 4, are supported in rotatable carriers 28, 28 on a turntable 21 by means of which the parts may be brought in turn into engagement with a fixed upper mould part 47 mounted in a rotatable carrier 44. The turntable 21 is rotated by a motor 24 and is vertically movable, to close or open the mould parts, by jacks 26. The mould carriers are belt driven and braked. Each lower mould part is elastically centred in the carrier by springs 28a. The melt is poured from a ladle 59 through a rotatable supply tube 48 which is belt driven and braked. To the supply tube is attached a tube 65 through which predetermined quantities of mould coating substances may be supplied by a piston-actuated slide 68c and compressed air. -Evacuation may be effected, or a protective gas applied through a passage 62 in the mould cover 60. Cooland such as pressure air is directed to the mould joint from openings in a circular conduit 94, the mould parts being bevelled, 97, for better cooling. In addition, after the casting has solidified sufficiently the mould parts are separated slightly to allow the coolant to reach the casting. As soon as possible the mould is opened by lowering the turntable 21, which is then rotated to carry away the casting in the lower mould part, while another lower mould part is brought into position beneath the upper mould part 44. An extracting device for removing a casting R from the still-rotating lower mould part 40 and carrying it away comprises a slide 70 movable by a cylinder 72 and on which is mounted a turntable 74. Gripping jaws 84 are fitted to pull rods 83 whose inner ends carry rollers 87 inserted in grooves in a conical clamping head 89<SP>1</SP>. With the turntable 21 in its upper position closing the mould, the head is movable vertically upwardly by a piston in cylinder 90 to move the jaws inwardly to grip the casting R, which after lowering of the turntable 21 and hence the mould part 40, may be deposited on a conveyer outside the chamber 20 by movement of the slide 70. In a modification, Fig. 6, the annular mould cavity is interrupted by inner projections 143a, 143b so that two arcuate castings are made. The pouring tube has two diametrically opposed outlets, and is located and rotated with the upper mould part carrier by a pawl which engages one of a pair of notches 142a, 142b so that pouring of the melt starts or finishes at the projections. The pouring tube is also rotatable by means of a belt drive and after the desired speed of the closed mould and coupled pouring tube is reached, the pouring tube is given a slightly higher speed than the mould by means of the belt drive at the moment the melt flows into the mould, so that the pouring outlets move relatively to the mould and between the two projections. Alternatively, the outlets may be disposed at different levels so as to cast two rings in two annular mould cavities, one above the other. In a further modification, the mould incorporates a vertically movable core.