| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve a buckling strength by effectively preventing the shaking of a hydraulic cylinder for elongation/contraction in an elongated/contracted boom. SOLUTION: In the opposite rod protruding end portion 7A2 of the cylinder tube 7A of a hydraulic cylinder 7 for elongation/contraction, each shaking stopping mechanism is provided to have an abutting member, where the opposite rod protruding side end portion 7A2 is bought into contact with/separated from the inner surfaces of corresponding booms 3B and 3C or 3C and 3D, and always pressed in a direction for abutment on the inner surface by a proper pressing means. Thus, the abutting member of he shaking stopping mechanism is abutted on the inner surfaces of the booms 3B and 3C or 3C and 3D by the pressing force of the pressing means, and the shaking of the opposite rod protruding side end portion 7A2 is prevented as much as possible.</p> |
