| 摘要 |
<p>The invention relates a drilling mast, including: a stationary structure (4); a jar (6) slidably mounted on said structure; a carriage (7) provided with a drilling head (23) and slidably mounted on the jar; two jacks (8) on which the jar rests; two pulleys (21) rigidly connected to the jar, over each of which a cable (22) is strung, a first end of the cable being attached to the structure and the other end thereof being rigidly connected to the carriage, such that, when the jack moves in one direction, the carriage moves in the same direction; and a drawing tool (24) mounted at the bottom of the jar and provided for extracting a drill rod (2). Thus, when the jar (6) moves, the tool (24) is directly engaged with the jacks (8), such that the drawing force of the tool (24) is equal to the sum of the forces generated by all of the jacks, as opposed to the carriage which, due to the strung cables, has a force equal to half of that of the tool. However, the travel of the tool (24) can only be equal to the travel of the jacks (8)</p> |
