| 摘要 |
PROBLEM TO BE SOLVED: To eliminate necessity for provision of a guide sheave to be solely devoted for moving an upper spreader while a method to move the upper spreader between the boom base end and the tip using a hook windup rope and a jib derricking rope is adopted. SOLUTION: A hook windup guide sheave 19 as part of a hook windup device is installed in a position serviceable for leading the hook windup rope 17 to the upper spreader 9 at the time of assembling and disassembling a crane. When two winches for jib derricking and hook winding are operated for moving the upper spreader 9 between the boom base end and the tip, the tension of the jib derricking rope 7 is sensed, and the winch operation is controlled so that the rope tension is kept within the proper range. COPYRIGHT: (C)2005,JPO&NCIPI
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