GB573669A - Hydraulic clutches - Google Patents

Abstract

573,669. Hydraulic clutches. THOMAS, A. N. Sept. 27, 1943, No. 15822. [Class 69 (ii)] A hydraulic clutch comprises driving and driven shafts 28, 32 operatively connected to a pump, and a valve 70 which controls circulation of fluids of different densities, e.g. oil and air, either individually or in mixture through the pump. The latter comprises sun and planet gears 46, 47 carried respectively by the driven and driving shafts and housed in a casing 23 partially filled with liquid. An axially slidable control valve 70 co-operates with pump inlet and exhaust passages 67, 68 and has a central chamber bounded by walls 70c, 70D which extend into close proximity with the shaft. Thus, when the drive shaft rotates and the liquid forms a circumferential ring, air only has access to the chamber. In the position of the valve shown, air only is admitted to the pump inlet passages 67, and shaft 32 remains stationary. Movement of the valve to the left progressively closes the inlet passages to the air port Z and opens them to oil ports 70G. At the same time the exhaust ports are gradually closed. Finally, exhaust and inlet ports are closed and shaft 32 rotates at the same speed as the driving shaft. Relief valves 74 are arranged on the exhaust conduits and further relief valves 84 open under centrifugal force at predetermined speeds to relieve excess air pressure in the casing.