Patent ID: 6230090
Filing Date: 2001-05-08
Classification: E02F

Abstract:
An interference prevention system for a 2-piece boom type hydraulic excavator, said interference prevention system being installed in a 2-piece boom type hydraulic excavator comprising an excavator body, a work front mounted on said excavator body and having a plurality of front members including first and second booms and an arm which are vertically rotatable, a first boom cylinder for driving said boom, a second boom cylinder for driving said second boom, an arm cylinder for driving said arm, a first-boom flow control valve for controlling a flow rate of a hydraulic fluid supplied to said first boom cylinder in accordance with an operation signal from first-boom operating means, a second-boom flow control valve for controlling a flow rate of a hydraulic fluid supplied to said second boom cylinder in accordance with an operation signal from second-boom operating means, and an arm flow control valve for controlling a flow rate of a hydraulic fluid supplied to said arm cylinder in accordance with an operation signal from arm operating means, said interference prevention system serving to restrict movement of said work front when a predetermined position of said work front comes close to said excavator body, wherein said interference prevention system comprises:attitude detecting means for detecting an attitude of said work front, andcontrol means for receiving detection signals from said attitude detecting means and, when the predetermined position of said work front comes close to said excavator body, outputting a command signal to said second-boom flow control valve so that said second boom is moved in a dumping direction.