GB773268A - Improvements in or relating to piston ring assemblies - Google Patents

Abstract

773,268. Piston-rings. LIGHT PRODUCTION. Ltd. July 13, 1955, No. 20351/55. Class 122 (1). A piston ring assembly comprises a pair of thin split rings 16 adapted to engage opposite sides of the piston-ring groove and urged radially outwardly by a split expander ring of wavy formation in plan provided on each side of ts radially inner crests with axially extending lugs 11 on which the rings 16 are supported at their inner peripheries. The expander ring is made from spring steel strip having rectangular openings 10, separated by parts 12, and lateral lugs 11 symmetrically disposed with respect to the openings, and bent first into sinuous shape and then into a circle with the radially flanged ends 18 abutting. The inner curved peripheries 15 of the split rings 16 are supported on the faces 13 of the lugs 11 and the inner radial faces of the rings 16 are supported by the narrower portion of the expander ring. The outer peripheries 17 of the rings 16 may also be curved. The width across the lugs 11 is slightly less than that of the piston-ring groove and the complete assembly is a push fit in the groove, the expander ring being axially resilient due to the openings 10 and of such circumference that with its ends 18 abutting it will not bottom in the groove. In a modification, the waves of the expander ring are rectangular and the edges 19, Fig. 6, of the narrower part of the ring converge outwardly, the width of the assembly being slightly greater than that of the piston-ring groove so that when it is sprung in the latter, the splitrings 16 lie substantially flat against the edges 19.