A lever located on a fulcrum or shaft, one end on the valve stem and the other either on the push rod or directly on the camshaft lobes As the camshaft rotates, the arms rock on their fulcrums causing the valves to open and close
A curved lever that pivots in the middle One end is attached to the top of the valve stem In overhead-valve engines the other end is attached to the push rod In some overhead-cam engines the other end is attached directly to the camshaft lobe As the camshaft rotates, the rocker arms pivot causing the valves to open and close Also see ball joint rocker arm and high lift rocker arms
These are pivoting levers that transfer the movement caused from the rotating lobes of the camshaft to the opening and closing intake and exhaust valves