| 摘要 |
A housing including longitudinally extending tubular members interconnected to allow controlled relative bending thereof, during a drilling operation, a rotary drive transmitting torsion bar extending generally longitudinally within the housing to controllably bend in response to relative bending of said members, a rotary drill bit operatively connected to said torsion bar to be rotated as the bar rotates, a rotary drive operatively connected to the torsion bar to rotate the bar, means for controlling relative bending of the said members during torsion bar rotation and as a function of such rotation.
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