| 摘要 |
A drilling rig carried by a vehicle includes a mast having upper and lower sections. The lower section is mounted on a support surface of the vehicle which is maintained parallel to the ground surface during drilling. The upper section is secured to the lower section so that the longitudinal axes of the upper and lower sections are offset at a predetermined acute angle and the top of the upper section is beyond an edge of the surface. A rotary power drill head is translatable along the length of the lower section. A cable pulled by a draw works on the vehicle extends over a pulley at the top of the upper section and thence downwardly. The angle of the surface is controlled so that during vertical hole drilling the surface is horizontal and the power drill head is directly above the hole. During pipe hoisting, the pulley is directly above the hole so the cable extends downwardly in line with the hole, while it is attached to the pipe. During drilling, the cable extends over a sheave, at the intersection of the two sections, and is connected to the drill head, to assist in supporting it. Adjustable length support arms extend from the top of the upper section to bear against the ground, outside opposite sides of the mast. The support arms and a pair of outrigger supports for the surface of the vehicle intersect a common straight line on the ground. A retractable, hydraulically actuated strut connects the upper and lower sections together, to raise and lower the upper section relative to the lower section and fold the upper section on top of the lower section, during transport.
|
