| 摘要 |
The apparatus has a housing arranged to function as a length of drill string, including a fluid tight fluid conducting bore, with means at each end for connecting to a continuing drill string. The housing has two principal portions bearingly connected for rotation and axial constraint. A spring loaded one way clutch connects the two portions such that torque can be conducted therethrough in only one rotational direction. The clutch has one, spring loaded, axially moving element to actuate the clutch unless locked by optional provisions. The axial movement, optionally, actuates a valve in the fluid conducting bore to create a pressure drop in the fluid stream when the clutch is disengaged to provide a pressure signal that can be detected at the surface to indicate that the clutch is disengaged.
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