Bird-Johnson Company

Charles A Busche

Joseph L Cavallaro

Arthur J Richards, Jr

An oil distribution box for a marine controllable pitch propeller of the type having a main hydraulic servo within a hub for controlling the pitch of propeller blades rotatably carried by the hub and including a directional valve actuated by a tubular valve rod extending through the propeller shaft from the oil distribution box comprises an outer stationary housing, a shaft received within the housing and coupled to the propeller shaft and an auxiliary servo chamber cylinder coupled to the shaft. A piston received in the servo chamber is coupled to the valve rod. Oil is supplied to the valve rod through an elongated annular supply chamber defined between the shaft and the valve rod by spaced-apart seals, a port in the valve rod opening to the supply chamber, a port in the shaft opening to the supply chamber and a journal clearance seal between the housing and shaft in register with the port in the shaft. Oil is supplied to the servo chamber selectively to the chamber sections on the respective opposite sides of the piston through, for each section of the servo chamber, a supply-return passageway in the cylinder communicating with the servo chamber, a passage in the housing, and a journal clearance seal between the housing and the servo chamber cylinder in register with the passage and the passageway. A normally closed pilot-operated check valve in each passageway isolates the servo chamber from the clearance seals except when oil is supplied to the auxiliary servo to produce a pitch change.

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Hanson, MA, United States of America

Charles A Busche