| 摘要 |
A telescopic boom includes three or more sections which may be pivoted if desired. The innermost section is incapable of moving in the longitudinal direction, whereas the other sections are adapted to be concurrently dislocated in the longitudinal direction relative to each other. Only a drive mechanism on the innermost section is adapted to be actuated from an outside source, whereas the other sections are driven by the relative motion of the sections movable in the longitudinal direction. |
