| 摘要 |
<p>The gantry is adjusted for working height by using its own lifting gear (11b) to manipulate additional sections utilised for raising the height of the columns (8). Each of these has integral hydraulic rams (21), attached to the fixed portion (4) of each column. When these are extended the boom (1) is raised, leaving a gap for an additional section. Each section (20a) is anchored to a monorail (26) under the boom, near the column. Immediately sufficient space is provided by the hydraulic rams, each section is slid (42) into place and bolted to the column. The hydraulic ram cage (18) has three sides only to permit this operation.</p> |
