Patent ID: 7584611

Claim:
A control system for a hydraulic construction machine comprising: a prime mover; at least one variable displacement hydraulic pump driven by said prime mover; at least one hydraulic actuator driven by a hydraulic fluid from said hydraulic pump; and revolution speed control means for controlling a revolution speed of said prime mover, wherein said control system further comprises mode selection means for selecting a control mode related to said prime mover; load pressure detection means for detecting load pressure of said hydraulic pump; and target revolution speed setting means which stores a prime mover revolution speed (ΔN 0 ) preset therein to reduce the revolution speed of said prime mover with a rise of the load pressure of said hydraulic pump, and which, when a particular mode is selected by said mode selection means, determines a corresponding prime mover revolution speed (ΔN 0 ) by referring to the preset prime mover revolution speed (ΔN 0 ) based on the load pressure of the hydraulic pump detected by said load pressure detection means and sets a target revolution speed (NR 1 ) for said revolution speed control means based on the determined prime mover revolution speed.