| 摘要 |
The boom is assembled from sections (4) of different lengths. A tie rope (9) runs between the frame and the platform and at the same distance from the two derricking axes, thus determining the platform derricking angle. The rope runs part-way round curved supporting members (14) at each position. Its length can be adjustable to suit the boom length, its surplus length being wound onto a drum behind the frame. ADVANTAGE - Easy erection and dismantling. |
