Link Motions

Combinations of rods and levers by which the rotary motion of cranks and eccentrics, or the reciprocating motion of the piston, is transmitted to the steam valves of an engine. The design of these mechanisms is to enable the engine to be easily and rapidly reversed, and to admit of adjustable cut-off of steam admi ion on either forward or back IMG:content-1111.jpg:[graphic][merged small] Fink's Link Motion. ward gear. The most usual of these is the STEPHEN SON LINK MOTION (q.v.), used on locomotives; the Gooch. which reverses the curvature of the Stephen son link, and raises and lowers the valve stem; the Allan, which shifts the link and the valve stem equally in opposite directions and uses a straight link; the Fink, which uses one eccentric only, with which the link is solid; and the Walschaert gear. See JOY VALVE GEAR.