Hydrostatic engine control

Claim 1

In a multipiston hydrostatic engine of the radial cylinder type the combination of a crank case, a crank shaft rotatably mounted in said crank case and having a pair of axially spaced radial flanges therein and a crankpin extending axially between said flanges, said crank pin having a pair of plane side surfaces at opposite sides of and in parallel relation to a radial plan through the journal axis of said crankshaft, and diametrically opposite arcuately convex surfaces extending axially between said flanges and transversely between said plane side surfaces; an annular slide block surrounding said crank pin in radially back and forth shiftable relation thereto, said slide block having a pair of parallel diametrically opposite plane internal surfaces in contacting relation with said plane parallel side surfaces of said crank pin, axially opposite radial end faces in contacting relation, respectively, with adjacent radial surfaces of said flanges and radially opposite arcuately concave internal surfaces extending axially between said end faces and circumferentially between said parallel internal surfaces whereby a pair of radially expandable and contractable fluid chambers are provided at diametrically opposite sides of said crank pin between the latter and said slide block; annular sealing means operatively interposed between each of said axially opposite radial end faces of said slide block and the adjacent radial surfaces of said flanges; and linear sealing means extending axially of said crank pin and operatively interposed between each of said side surfaces of the latter and the adjacent plane internal surface of said slide block, said crankshaft being provided with internal fluid passages communicating, respectively, with said fluid chambers; and thrust transmitting means operatively interposed between radially reciprocable engine pistons and said slide block.