GB207066A - Improvements in mine signal apparatus - Google Patents

Abstract

207,066. Dale, W. B., Hopkinson, R. A., and Hopkinson & Co., Ltd., J. Dec. 30, 1922. Cam actuated pumps; regulating delivery by throttle valves.-A cancelling device for minesignalling apparatus is actuated by a pump driven by the winding engine, cancellation being effected when the engine starts from rest. The engine shaft D carries cams C, Fig. 3, which depress respective plungers such as B to operate pumps having inlet valves J and outlet valves K, the plungers being restored by spring- controlled arms G. Fluid such as oil is thus pumped from the main chamber A through passage L, Fig. 2, to a cylinder containing the plunger M which is adapted to raise an arm N and so to turn a spring-controlled shaft 0 and lower an arm R which drags with it the cancelling lever T. Excessive pressure is relieved by a safety-valve 25, and further a centrifugal clutch may be arranged to disconnect the pump at high speeds, or, as shown, the arm N at the upper limit of its travel may engage lock-nuts 14 and so lift the stem 13, restricting at 15 the oil supply of the suction manifold 16, Fig. 3, which leads to the suction valves J, and thereby preventing the pump cylinders B from rising through their full stroke. Thus the pressure is maintained at a moderate value after cancellation has been effected. In order that the pressure may be released when the engine stops, a leak is provided at 19, Fig. 2, and is controlled by a friction-held sleeve 20. The arm N on its upward motion opens the leak by engaging nuts 22 and lifting the sleeve; on its downward motion at the stopping of the engine, it engages shoulder 23 and depresses the sleeve and so closes the leak ready for the next operation. Specification 186,373, [Class 118 (ii), Signals], is referred to.