Rŏck'-sháft, n.

noun

n. (Mech.) A shaft that oscillates on its journals, instead of revolving; more strictly, a vibrating shaft for modifying motion in the valve-gear of a steam-engine;—called also rocker and rocking-shaft.

A labeled mechanical diagram of a rocker mechanism and valve. — A, rock-shaft; B, rock- er arm; C, rocker- box; D, gab; E, valve.