| 摘要 |
An outer-boom crane comprising a first boom section (1) and an outer boom (2) which is pivotable relative to the first boom section by means of a hydraulic cylinder (12) whose one end is connected to the first boom section by a first articulation (13) and whose opposite end is connected to the outer boom (2) by a second articulation (14). Between the two booms (1, 2), there is provided at least one link device (15) which is connected to the first boom section by a third articulation (16) and to the outer boom (2) by a fourth articulation (17) which is spaced from the second articulation (14) and from the third articulation (16), more specifically with the third articulation (16) located at a greater distance from the fourth articulation (17) than the second articulation (14). By means of the link device (15), the outer boom (2) can switch articulation points so as to pivot, within its working range, about a fourth articulation (17) which is situated at a great distance from the main articulation (3) of the first boom section while, when pivoting towards and away from its parking position on the upper side of the first boom section, it is pivoted about the third articulation (16) which is situated considerably closer to the main articulation (3). |
