| 摘要 |
<p>DRILL BITS WITH CONE RETENTION MEANS A drill bit is shown which is connectable to the lower end of a rotary drill string for use in drilling oil and gas wells as drilling mud is circulated downward through the string, out the bit, and upwardly within the annulus between the string and well bore so as to remove cuttings therefrom. The bit has cones which are mounted for rotation about thrust bearings which extend inwardly from the lower ends of legs which depend from a shank at the upper end of the bit body which is attached to the drill string. The cones are secured on the bearing journals by a system of sealed liquid passages and reservoirs which provide a liquid lock requiring no retaining bearings or washers.</p> |
