GB484930A - Improvements in and connected with the casting of piston and like metal packing rings - Google Patents

Abstract

484,930. Casting piston &c. metal packing rings. OUBRIDGE, W. A. Nov. 19, 1936, No. 31669. [Classes 83 (i) and 83 (ii)] Moulds.-In the manufacture of piston &c. packing rings, dry sand moulds are used which are dried previous to the casting operation, and which are each formed with a ring 10, Fig. 4, a central hole 9 and a plurality of radial runners 11 communicating between the hole and ring groove at a number of points around the inner circumference of the latter. The pattern plate used for forming the dry sand mould is provided with an upstanding ring portion which may be truely circular or may be a split ring with a wedge inserted to give an involute of a cycloid shape to the ring ; thin webs connect the ring to a central hub portion on the pattern and a shroud ring surrounds the whole to facilitate ramming in the sand. The mould, Fig. 4, may be baked while on the pattern ring or after removal of the latter. A number of moulds 8, Fig. 5, are arranged vertically in a frame 12-14 their hollow centre portions 9 forming a common downsprue into which casting metal is poured the web recesses 11 giving communication to, the ring grooves 10. The multiple casting thus formed is separated at 17, Fig. 8, to give the individual ring elements, and the webs 18 and bosses are cut away prior to the final machining and grinding operations.