| 摘要 |
Provided is a mobile crane (1) capable of adjusting a counterweight (50) height with no use of a costly hydraulic cylinder. The mobile crane comprises a lower propelling body (10), an upper slewing body (20), a boom (25) pivotably attached to the upper slewing body, a mast (30) which is at the rear of the boom (25) and adapted to be raised and lowered so as to raise and lower the boom (25), a counterweight (50) which is at the rear of the upper slewing body (20) and hung from the mast (30) through a guy line (54), and a counterweight-lifting cylinder (60) attached to the counterweight (50) so as to be extended to vertically push up the counterweight (50) with respect to a ground surface. The counterweight-lifting cylinder (60) has a cylinder body, a piston (64) partitioning an internal space of the cylinder body (62) into an upper head-side cylinder chamber (63h) and a lower rod-side cylinder chamber (63r), and a rod (66) extending from the piston (64) downwardly beyond a lower end of the cylinder body (62), the counterweight-lifting cylinder (60) is extended by supply of a hydraulic pressure into the head-side cylinder chamber (63h) and retracted by supply of a hydraulic pressure into the rod-side cylinder chamber (63r) . |
