DRIVING CIRCUIT FOR ONE-CHANNEL TYPE HYDRAULIC CYLINDER, AND EXPANSION HEAD USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a driving circuit for a hydraulic cylinder that allows execution of sure telescopic drive by supplying pressure oil as if from two channels in a hydraulic cylinder having a one-channel hydraulic conduit for supplying pressure oil from the outside. SOLUTION: In a working machine driven by a hydraulic cylinder, a driving circuit for a one-channel type hydraulic cylinder is configured as follows. A one-channel hydraulic conduit is extended to the hydraulic-cylinder side so as to supply pressure oil from the outside. It is configured to branch the conduit connected to the rod-side space and the piston-side space of the hydraulic cylinder respectively from the extended end via a channel switching valve. The channel switching valve is switched by a pressure change of the pressure oil supplied from the outside to the one channel. Thereby, the pressure oil can be selectively supplied to one of the rod-side space and the piston-side space of the hydraulic cylinder. COPYRIGHT: (C)2011,JPO&INPIT