Hydraulic pressure actuating apparatus for circuit breaker

Abstract

In a hydraulic pressure actuating apparatus for a circuit breaker, contacts of the circuit breaker have a moving contact and a stationary contact for turning on/off current. A shaft, at an end portion of which is attached the moving contact, and at the other end of which is attached a piston, is received within a cylinder. A directional control valve exchanges oil pressure for actuating the piston. For changing over the directional control valve, pilot valves are provided. Each pilot valve has a pair of valve bodies, each opposing to each other, and springs. One of the valve bodies is able to stroke up to contact with the valve body of the other valve body, therefore giving no ill influences upon actuating time, even if drawback occurs in the pilot valves in the hydraulic pressure actuating apparatus for the circuit breaker.

Dependencies are inferred from the claim text.