GB711996A - Improvements in or relating to valves - Google Patents

Abstract

711,996. Fluid-pressure servomotor-control systems; valves. BENDIX AVIATION CORPORATION. April 1, 1952 [April 7, 1951], No. 8293/52. Class 135 A control device for a fluid-pressure actuator comprises a spring-loaded plunger with a passageway therethrough affording communication between the pressure and working ports, a first valve spring-loaded to the position closing off communication between the working and reservoir ports, a tappet between this valve and a ball valve normally closing off the passageway through the plunger, and a condition-responsive device acting on that end of the plunger opposite the valves. In an embodiment, applicable to a system for actuating hinged flaps controlling the flow of cooling air through a radiator in the cooling system of an internal combustion engine, the valves comprise two balls 76, 96, spaced apart by a grooved pin 110, and controlling the flow of a hydraulic medium from an accumulator port 66 to a port 68 connected to a servo-cylinder, or from the port 68 to an exhaust or reservoir port 70. The temperature of the water jacket of the engine is detected by a thermal bulb and the resultant pressure produced in the thermal liquid is applied to the inside of a bellows 112. When pressure increases in the bellows, a rod 62 is moved to the left to abut against ball 76 so that the passage 78 through the rod connecting ports 66, 68 is shut off, and the continued movement of the rod will cause ball 96 to be pushed off its seat in a partition 84 in the casing of the device and allow the liquid in the servo-cylinder to exhaust from port 68 to port 70. The datum temperature is varied by adjusting the relative positions of a screwed sleeve 54 and a bushing 114.