HYDRAULIC CONTROL DEVICE OF INDUSTRIAL MACHINERY

摘要

A hydraulic control device of industrial machinery such as a reach stacker capable of efficiently controlling a large flow of pressure oil by a simple configuration of hydraulic devices, comprising first and second variable displacement hydraulic pumps (20) and (23) driven by the engine (3) of the reach stacker, main hydraulic circuits (21) and (24) of two systems connecting these hydraulic pumps to a tilt cylinder (8) and a telescopic cylinder (9) corresponding to the hydraulic pumps, and a derricking control valve (22) and a telescopic control valve (25) installed in the main hydraulic circuits of the two systems and controlling the flow and direction of the pressure oil supplied to the tilt cylinder (8) and the telescopic cylinder (9). A merge block (34) forming a merge circuit for merging the pressure oil in the main hydraulic circuits (21) and (24) of two systems according to the operating conditions of the tilt cylinder (8) and the telescopic cylinder (9) is installed in the main hydraulic circuit positioned on the upstream side of the both control valves (22) and (25).