| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a jib crane which is not deformed even by an external force such as storm since the strength and the accuracy of a base frame are high. <P>SOLUTION: In the jib crane, a slewing frame 2 is mounted to an annular base frame 12 in a slewing manner, and crane components are mounted to the slewing frame 2. A center cylinder is arranged at the center position of the base frame 12, and the center cylinder and the base frame 12 are connected to each other via a plurality of spokes 51, 52, 53 arranged in a radial manner. The plurality of spokes 51, 52, 53 secure connection strength and accuracy in the normal direction of the base frame 12. Furthermore, even if an external force such as storm is applied, the external force is transmitted to the opposing side of the base frame 12 by the spokes via the center cylinder, stress is balanced, and the deformation and the damage of the base frame 12 can be prevented. <P>COPYRIGHT: (C)2012,JPO&INPIT |
