| 摘要 |
A device for improving safety during operations of storing or extending a boom of a crane. A corresponding relationship between a boom hoisting angle ( theta ) and a length of rope (s) is beforehand set when an attitude of a boom (4 ) shifts from a working attitude (A) to a working attitude (B). Means (14) for detecting a boom hoisting angle detects a current boom hoisting angle ( theta ), and means (18) for detecting a current length of rope detects a length of rope (s). On the basis of the current boom hoisting angle detected b y the boom hoisting angle detecting means (14), and the current length of rope (s) detected by the rope length detecting means (18), a boom drive device and a winch drive device are drivingly controlled so that a boom hoisting angle and a length of rope equal the set boom hoisting angle ( theta p) and a length of rope (sp), respectively. |
