| 摘要 |
<p>The twoer crane boom is provided with lifting cable supports, to prevent this sagging and fouling the tracks. These supports move in unison with the travelling carriage. Each support (12) runs on wheels (14) and has an endless cable (16) passing over a pulley on each support. The upper part of the loop is fixed (17, 18) to the boom, the lower part to the carriage (4). Another cable (22) is fixed to one support, passing over a pulley (23) at the mast end (1), another at the free end and is fixed to the other support.</p> |
