| 摘要 |
<p>Apparatus is disclosed for use in a drill string during rotary well drilling, especially of shallow holes such as blast holes, to absorb the shock loads imposed upon the drill bit and drill. A floating solid piston in an outer tubular body separates a gas chamber from a liquid chamber and equalizes the pressure between the two. A mandrel with large diameter bearing surfaces is carried reciprocally within the body, and has annular lubricating cavities separated from the liquid chamber. Lubricating passages include one in which a pressurized gas in a cavity supplies lubricant under pressure to the various bearing and sealing surfaces. Cylindrical pins inserted between the mandrel and the outer tubular body transmit torque between the body and mandrel.</p> |
