GB769529A - Improvements in and relating to the manufacture of pistons - Google Patents

Abstract

769,529. Making pistons; casting composite articles. DAUB, R. April 25, 1952 [May 10, 1951], No. 2848/56. Divided out of 769,528, [Group XXVI]. Classes 83 (1) and 83 (2). A method of making a composite piston comprises providing a metal ring 41, Figs. 1, 3, formed on its upper and lower edges with integral circumferentially-spaced lugs 40 which project inwardly, casting light metal on to the ring to form the body of the piston with the lugs 40 embedded therein but leaving the ring 41 exposed externally of the piston, and thereafter machining said piston to remove said exposed metal ring, Fig. 4, and form a pistonring-groove having upper and lower walls 46, 47 formed by the lugs and intervening areas of light metal. The ring 41 is formed by stamping, rolling and bending from metal strip. In one embodiment, Fig. 5, the ring 49 with inwardly projecting lugs 40<SP>1</SP>, has three oft he lugs formed with extensions 51 which rest on the bottom of the mould. The piston body is then cast in the mould with the crown at the bottom. This crown may be subsequently drilled to a slight depth at each extension 51 and plugged and smoothed. In another embodiment, Fig. 7 (not shown), the ring is formed in halves. In another embodiment, Fig. 8 (not shown), a number of superposed rings are provided and connected together by integral lugs. The embedded lugs are of harder metal than the piston body.