| 摘要 |
PROBLEM TO BE SOLVED: To provide a climbing crane or a jib crane eliminating a derricking wire and a derricking winch by eliminating faults in a conventional climbing crane or jib crane whose jib has several derricking wires stretched among a plurality of sheaves to support the weight and lifting load of the jib, which increases a burden imposed on the derricking wires, a brake and the sheaves. SOLUTION: In this jib crane put in derricking motion by a hydraulic cylinder, a gantry provided with a plurality of sheaves at the apex is supported to a bottom boom put in derricking motion by the hydraulic cylinder supported to a revolving superstructure of a crane whose jib is put in derricking motion, and a gantry and the tip of the jib are connected by a pendant rope. A support frame provided with a plurality of sheaves at the apex is supported to the rear part of the revolving superstructure, and one end of a hoisting wire is wound into a winding drum, and the other end passed through a hook is passed through the plurality of sheaves and the plurality of sheaves. Using the tension of the hoisting wire applied to the hook when lifting load, the gantry is pulled to assist the hydraulic cylinder for putting the bottom boom in derricking motion. COPYRIGHT: (C)2005,JPO&NCIPI
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