Patent ID: 7431000

Claim:
A valve-operating system for an internal combustion engine, comprising a rocker arm having a valve abutment at one end thereof abutting against an engine valve and a cam abutment at the other end contacting with a valve-operating cam, and a pair of link arms each of which is supported at one end thereof on an engine body for swinging movement about an axis parallel to a rotational axis for said valve-operating cam and connected at the other end directly to the other end of said rocker arm for relative turning movement about an axis parallel to said rotational axis, said one end of at least any one of said link arms being swingably supported on said engine body for continuous movement within a plane perpendicular to the rotational axis for said valve-operating cam, and wherein said rocker arm is formed to be gradually thicker from the valve abutment at the one end toward the cam abutment at the other end, and wherein the other ends of the pair of link arms connected to the other end of the rocker arm are positioned on a line in an input direction from the valve-operating cam to the rocker arm.