| 摘要 |
A mobile lift crane (10) includes a central crane unit (20), a boom unit (40) and a counterweight unit (60). The central crane unit (20) has a carbody (22), moveable ground engaging members (24) and a rotating bed (23) mounted to the ground engaging members (24) with a rotatable connection such that the rotating bed (23) can swing with respect to the ground engaging members (24). The boom unit (40) has a support member (42), at least one moveable ground engaging member (44), and a boom (46) pivotally mounted on the support member (42). The counterweight unit (60) has counterweight (62, 64) on a support member (66). Rigging (52, 54) connects the boom (46) and counterweight unit (60) such that a load lifted by the boom (46) can be counterbalanced by the counterweight (62, 64). The boom unit (40) and counterweight unit (60) are connected to the central crane unit (20) by structural members (82, 84) that carry compressive loads and maintain the boom unit (40), the rotating bed (23) and the counterweight unit (60) in lateral alignment with each other, but allow relative vertical movement between the boom unit (40), the rotating bed (23) and the counterweight unit (60). A main mast (48) is pivotally mounted on the combination of the central crane unit (20), the boom unit (40) and the structural member (82) between the central crane unit (20) and the boom unit (40). In another embodiment, a counterweight unit (260) with a swing axis and boom unit (240) are connected directly together with a structural member (282). Ground engaging members (244) on the boom unit (240) can be rotated relative to a boom unit support member (242) such that the boom unit (240) i) can travel in an arc around the swing axis of the counterweight unit (260) and ii) travel in direction in line with the structural member (282). |
