POSTURE STABILITY CONTROLLER OF ARM TYPE EXCAVATOR

PURPOSE:To stabilize a posture to prevent inversion by controlling an actuator automatically so that moment of inversion calculated by detecting a boom elevation of an arm type excavator and oil pressure of a cylinder may not exceed a specific value. CONSTITUTION:A threshold value T0 of moment of inversion programmed in a CPU 17 of an attitude stability controller in advance is compared with a value T outputted to the CPU 17 through a control actuator detector 14 by detecting controlling pressure by means of shuttle valves 25 and 27 of a working machine. As a result, the value T reaches the value T0, an automatic manual selector valve 6 is controlled to a position (b) to change over to an automatic control. After that, when a switch of the working machine is set so as to make correcting control, an arm control valve 4 is changed over to a position (a), an arm cylinder 5 is extended to reduce the moment of inversion, and the value T comes within the threshold value T0. According to this constitution, the posture is stabilized, and work efficiency can be promoted without inversion.