| 摘要 |
<p>RAISE DRILL APPARATUS A drilling apparatus includes a ground engaging base, a torque transmitting apparatus for engaging and transmitting torque to drill pipe, and hydraulic cylinders connected to the base for moving the torque transmitting apparatus back and forth along the drill pipe axis. The hydraulic cylinders are connected to the base and include open ends facing away from the base. A piston rod is movable in and projects outwardly from the open end of each cylinder. A guide tube surrounds and is connected to the outer end of each piston rod. The guide tubes include inner surface portions which overlap and slidingly engage outer surface portions of the cylinders and the torque transmitting apparatus is connected between the guide tubes.</p> |
