| 摘要 |
<p>Rotary drilling equipment mounted on a traveling frame is moved up and down along a guide column by means of a first cylinder which surrounds and travels along the guide column and a second cylinder which surrounds and travels along the first cylinder. The guide column means is interconnected between a head frame and a base frame. The guide column means, the head frame and the base frame all together form a rigid closed box frame structure.</p> |
