| 摘要 |
The invention comprises an anti-blockage bearing for use in rotary core drilling of rock or other hard earth. Situate between the upper end of a freely suspended core barrel assembly and the core barrel coupling, the invention consists of spherical bearings retained within an upper and a lower annular housing, one or both of which are provided with a thrust race comprising a plurality of indentations and intervening ridges. During normal drilling, the core barrel is freely suspended within the outer tube of the lower end of the drill string. In the event of blockage, the core barrel will automatically be pushed upwards causing the thrust race of the lower housing member to bias the bearings against the thrust race of the upper housing member. As the bearings encounter the ridges and indentations of the thrust races, a jarring vibration action is imparted to the core barrel, dislodging the blockage. The vibrational frequency of the anti-blockage bearing can be modified by varying the number of spherical bearings or the number of ridges in the thrust races. |
