| 摘要 |
Provided is a mobile crane capable of adjusting a counterweight height with no use of a costly hydraulic cylinder. The mobile crane comprises a lower propelling body, a upper slewing body, a boom pivotably attached to the upper slewing body, a mast which is at the rear of the boom and adapted to be raised and lowered so as to raise and lower the boom, a counterweight which is at the rear of the upper slewing body and hung from the mast through a guy line, and a counterweight-lifting cylinder attached to the counterweight so as to be extended to vertically push up the counterweight with respect to a ground surface. The counterweight-lifting cylinder has a cylinder body, a piston partitioning an internal space of the cylinder body into an upper head-side cylinder chamber and a lower rod-side cylinder chamber, and a rod extending from the piston downwardly beyond an lower end of the cylinder body. the counterweight-lifting cylinder is extended by supply of a hydraulic pressure into the head-side cylinder chamber and retracted by supply of a hydraulic pressure into the rod-side cylinder chamber.
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