Steam enters at the top from the boiler and is admitted into the piston chamber A through steam ports by the action of the slide valve, B. The steam alternately strikes against the sides of the oscillating piston and passes through the exhaust port into the atmosphere. The crank C is attached to the piston shaft at bottom and is connected by a pitman rod D to the fly wheel. The crank pin operating in slot of valve rod E strikes the end of slot alternately and moves the upright valve arm F causing slide valve B to open and close steam ports.
[Virginia Downward & William M. Clark, 1930]

[Editor’s Note: This is a very unusual engine geometry. Instead of the classic sliding piston or slider crank mechanism, this engine uses a four-link mechanism similar to the Cornell Reuleaux Model C-1. FCM]

Francis Moon 2005-00-00