| 摘要 |
A multi-sectioned, telescopically extending column (20). This invention includes an extension mechanism (21) to extend the column and support the column sections (12, 14, 16) during extension, and a locking mechanism to lock each column section to the next when the column reaches its extended position. The column is particularly well suited for use as a crane boom, where individual boom sections are nearly fully extended each from within the other to minimize overlap between adjacent sections and reduce dead weight resulting from such overlap. The locking mechanism comprises a base collar (2a) on one column section which interlocks with a tip collar (51) on the adjacent section. The tip collar has a toothed inner contour (72, 73). The base collar has a rotatable locking ring (45) with a corresponding toothed outer contour. |
