| 摘要 |
<p>The crane has an extending vertical mast carrying a pivoted overhanging arm. The load of the front part of the overhanging arm is supported by a load support system attached. A rope of constant length has its front end anchored on the front part of the overhanging carrier member. The rear part is held on the rear part of a beam which projects at the rear side of the crane mast. The rope passes over a pulley above the base of the overhanging beam carrier. The rope length, position of the pulley and of the anchoring point is selected so that the rope is tensioned when the front part of the overhanging carrier is extended.</p> |
