| 摘要 |
A crane has a generally vertical, pivoting crane shaft (17) which supports a crane boom (23, 24) which can be raised and lowered by means of a hydraulic cylinder (28). The crane shaft (17) is supported at its lower end by a pivoting arm (20) which is actuated by a power unit (31), the crane shaft (17) being capable of being turned about its own longitudinal axis. Changes in the angle of the boom are reduced by the axis of the crane shaft (17) being tilted at a narrow angle by the supporting arm (20). The rotating movement of the crane shaft (17) is controlled by a link arm (37) which is firmly attached at one end and joined to an arm (36) which protrudes from the side of the crane shaft (17). <IMAGE> |
