| 摘要 |
PURPOSE:To prevent rotating of a sheave and a drum at an excessive number of revolutions at a time when a weight falls, by a method wherein a main rope, by means of which a weight is hung, is loosened to wind an auxiliary rope by means of a drum for auxiliary rope. CONSTITUTION:A weight 20 is hung using a main rope 23, and the main rope 23 is wound by a drum 5 for main rope. The top of the weight 20 is positioned in the proximity of the location under a weight clamp device 10, and with the hydraulic cylinder of the weight clamp device 10 actuated, a clamp claw 13 engages a grasping part 21 of the weight 20 to graps the weight 20. The main rope 23 is then loosened to wind an auxiliary rope 25 by a drum 6, and the main rope 23 is pulled by a neccessary lenght out to the side of the weight clamp device 10 so that the main rope 23 is prevented from stretching when the weight 20 falls and reaches a ground. The weight 20 is then released from the clamp claw 13 to cause it to fall. The weight 20 falls onto a ground without the rotation of a forward end sheave 4 of a boom 2. |
