This a planar model of the valve control linkage of a steam engine. The main piston is represented by the lower slider-crank mechanism and the sliding valve is represented by the upper slider-crank. The two mechanisms are coupled by the gear train on the right. A special feature of this coupled mechanism is the changable crank radius of the upper valve linkage that will control the amount of steam that enters the piston cylinder.

Francis Moon 2005-00-00