Patent ID: 7017470

Claim:
A flow control apparatus for construction heavy equipment, comprising: a control valve having a parallel passage to which hydraulic fluid of a hydraulic pump is supplied, a housing provided with a first load passage discharging the hydraulic fluid of the parallel passage to a first hydraulic cylinder and a second load passage discharging the hydraulic fluid to a second hydraulic cylinder, and a control spool provided to be movable in the housing and selectively communicating any one of the first and second load passages with the parallel passage; a flow control valve having a logic check valve provided to be openable between the first load passage and the parallel passage, and a logic control valve provided between the parallel passage and the logic check valve to control flow rate of hydraulic fluid supplied to a back pressure chamber of the logic check valve; and a load check valve provided between the second load passage and the parallel passage to restrict backflow from the second hydraulic cylinder.