| 摘要 |
A rolling cone cutter earth boring bit is provided with a load carrying bearing surface that can be renewed during the earth boring operation. A canister bearing element is positioned between the bearing pin and the rolling cone cutter. The rolling cone cutter rotates about the canister bearing element in a first direction during normal drilling operations. The canister bearing element has directional stops on its inside surface. These directional stops engage directional stops on the bearing pin and prevent rotation of the canister bearing element during normal drilling operations. The bearing surface can be renewed by reversing the direction of cutter rotation thereby disengaging the canister bearing element from the directional stops and allowing it to rotate in the opposite direction until a new bearing surface is in the load area. The new surface is locked in place by the directional stops or independent means and the rolling cone cutter again is rotated in the first direction for normal drilling operation.
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