| 摘要 |
PROBLEM TO BE SOLVED: To provide a broken type boom device capable of effectively utilizing the capability of driving means for boom hoisting. SOLUTION: This device includes a broken type boom 43 of which the base end portion is pivoted to a front end lower part of a girder 41 by a connecting axis 42; a front end boom 45 pivoted to the end face part to the end of lower part of the broken type boom 43 by a connecting shaft 44; a rod 48 of which one end part is pivoted to a front end upper part of the girder 41 by a pin 46, and of which the other end part is pivoted to the front end upper part of the front end boom 45 by a pin 47. An interval between the connecting shafts 42 and 44, the interval between the pins 46 and 47, physical relationship between the connecting shaft 42 and the pin 46, and the physical relationship between the connection shaft 44 and the pin 47 are defined, so as not to greatly vary the amount of variation in the front end boom 45 in the vertical direction of a center of gravity position G0 to G8, against an increase in the inclination of the broken type boom 43. COPYRIGHT: (C)2004,JPO
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