SAFETY DEVICE OF WORKING MACHINE

PROBLEM TO BE SOLVED: To provide a safety device for surely operating a luffing cylinder even at a stroke end, in the safety device of a working machine for detecting a load acting on a boom by holding the pressure of the luffing cylinder 4. SOLUTION: This safety device has a load moment regulating control means 12 regulating the operation of a telescopic boom when an actual load detected by a load detecting means reaches a limit load determined by a telescopic boom state by receiving a detection signal from the telescopic boom state 10 and the load detecting means 11, and a work range regulating control means 14 regulating the operation of the telescopic boom when the telescopic boom state reaches a limit work range determined by the telescopic boom state by receiving a detection signal from a telescopic boom state detecting means, and switches so as to output a control signal from the load moment regulating control means to a telescopic boom operation control means when a control signal from the work range regulating control means is not detected when a stroke end detecting means detects the stroke end state of the raising cylinder by a switching means 15. COPYRIGHT: (C)2009,JPO&INPIT