| 摘要 |
PROBLEM TO BE SOLVED: To provide a work range limiting device for a construction machine for limiting a movable range of a jib by a work range limiting parameter inputted by an operator, and capable of gently stopping the jib when the jib approaches the vicinity of a movable range limiting position. SOLUTION: An inputted work range limiting value is converted into an angle by a parameter setting/various arithmetic operation part. A stopping angle of one jib and a speed reduction starting angle are always arithmetically operated together with information on the jib length assuming that the other jib is fixed. A control pressure value of a C/V is calculated on the basis of the arithmetically operated stopping angle, the speed reduction starting angle, and an angle detected from a jib angle detector, and a jib derricking limiting current value is arithmetically operated from a control characteristic of a jib derricking proportional valve, and is outputted to respective proportional valves. The limiting current value outputted to the respective proportional valves limits command pressure supplied by operation of a jib operation lever. The C/V sends driving pressure oil of a flow rate according to the command pressure limited by the parameter setting/various arithmetic operation part 5 to a motor. The motor derricks the jib by rotating a jib derricking drum. COPYRIGHT: (C)2003,JPO
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