Patent attributes
The present invention is directed to controlling an operation oil supplied to an option apparatus without changing a design of a control valve assembly which controls an operation oil supplied to a traveling motor, etc. when additionally engaging an option apparatus to a small size excavator. In a hydraulic system for a heavy equipment which includes a plurality of hydraulic pumps, a main control valve which is switched by a pilot signal pressure and controls an operation oil supplied to a left and right side traveling motor and a work apparatus, and a pilot pump which supplies a pilot signal pressure to the main control valve, there is provided a hydraulic system for a heavy equipment option apparatus which includes a straight traveling control valve which combines an operation from a plurality of the hydraulic pumps and supplies to the left and right side traveling motors and disconnects an operation supplied to the traveling motor when the same is switched by a pilot signal pressure, and an option apparatus control valve which is switched concurrently with the straight traveling control valve by a pilot signal pressure and controls an operation oil supplied from one side hydraulic pump to an additional option apparatus.
