| 摘要 |
An in-hole motor drill assembly has the rotor of the motor which may be connected to the drill bit through a shaft connected to the rotor, and a housing which may be connected to the running string, and a normally disengaged clutch between said housing and said shaft. Means are provided for engaging the clutch by exerting a negative force on said housing, which is applied to the shaft by a pick-up bearing, if the bit is stuck against upward movement. The shaft can be rotated by rotation of the running string. In normal operation, during drilling, the clutch is disengaged to permit the shaft to rotate relative to the housing. The bearing which picks up the shaft and bit, during normal off-bottom circulation or retrieval of the assembly, is constructed to permit longitudinal movement of the housing relative to the shaft, when the bit is stuck, to engage the clutch.
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