Self-sealing coupling with bypass for hydraulic circuit

Abstract

In a self-sealing coupling with a bypass for a hydraulic circuit designed to connect a hydraulic sub-circuit to a midway portion of a main circuit of a hydraulic device, there is provided a coupling body with an input passage, an output passage, an input passage side and an output passage side self-closing valves and a bypass valve. The bypass valve is provided with a cylindrical valve element which is reciprocatively slidable within either one of said input passage and said output passage so as to open and close that one passage relative to a bypass provided therebetween. The cylindrical valve element is adapted to be moved together with the self-closing valve element provided in the one passage, to be shifted to a bypass valve opening position where the bypass is opened by the cylindrical valve element valve closed condition. This causes the one self-closing valve element to be pushed outwardly by a valve closing force exerting means, to close the one self-closing valve port and to be shifted to a bypass valve closing position where the bypass is closed by the cylindrical valve element in a valve opened condition the one self-closing valve element in this condition can be pushed back inwardly by an external force so as to open the one self-closing valve port. The valve opening and closing stroke of the one self-closing valve element and the cylindrical valve element is selected to be larger than the corresponding stroke of the other.