US Patent 7314029 Variable valve timing device adapted for internal combustion engine

A variable valve timing device, adapted for an internal combustion engine, includes a cam shaft having a first cam surface, a rocker arm rotatably supporting a first roller and enabling a valve to be opened by its swing movement when the first roller is pressed, a drive link rotatably supporting a second roller and moving to drive a connecting pin when the second roller is pressed by the first cam surface, a swing cam having a second cam surface and being swingable at a center of a stationary support shaft, when it is pressed by the drive link through the connecting pin, so that the second cam surface presses the first roller, and an actuator for changing a position of a third cam surface to vary a position of the drive link.