| 摘要 |
<p>A telescopic mast comprises a plurality of mast sections (2, 3, 4) which can be displaced axially relative to one another while guided by each other. The sections are arranged to be moved out of one another by means of a continuous line (13), which passes and co-acts with all mast sections, from the outermost to the innermostsection. Each mast section (2, 3, 4) includes at least one lower line-guide pulley (5, 6, 7) and one line-returning means (8, 9, 10) arranged at the upper end of a respective section. That part of the line (18) extending between the pulley (5) and the line-returning means (8) of one section (2) and between said line-returning means (8) and the guide pulley (6) of the nearest inwardly lying section (3) is fully protected in a space located between said sections (2, 3). The sections suitably comprise open-ended, closed-wall cylinders (2, 3, 4) arranged to fit within one another with a small clearance therebetween and which enable the mast to be used in the absence of guys. </p> |
