Corrugated expander for piston ring assembly

摘要

The annular expander of a piston ring assembly with vertically extending notches each of which is formed on either side of a plurality of circumferentially spaced upstanding tabs projecting from the top and bottom edges of the expander. The tabs, which form the abutments for the inner peripheral edges of upper and lower annular side rails, the outer peripheral edges of which are in sliding contact with a cylinder wall, undergo elastic deformation made possible by the notches when the corresponding side rails are subjected to a strong force received from the cylinder wall owing to piston wobble during reciprocation. The elastic deformation of the tabs assures that the side rails will remain in contact with the cylinder wall at all times during the reciprocation of the piston.