| 摘要 |
A directional drill bit utilizing pressurized fluid as a means for eroding earth in a forward path of the bit and being used to drill at least a portion of an arcuate path, comprises an elongate hollow body having two sections joined one to the other by a flexible joint, a box end connection, a jet nozzle, an articulation device comprising a spring and a stop, the articulation device being responsive to changes in fluid pressure by permitting a forward portion of the bit bearing the nozzle structure to change angular position with respect to an aft portion of the bit, by the forward portion moving from a first position relative to the aft portion to a second position relative to the aft portion. The spring is positioned in a manner which defines an initial, pre-selected degree of axial alignment describing a first angle formed by the relative position of the longitudinal axis of the first section with the longitudinal axis of the second section when the elongate hollow body is in its "at rest" position, that is, when no fluid is flowing through the drill bit. The stop is positioned in a manner which defines a final, pre-selected degree of axial alignment describing a second angle formed by the relative position of the longitudinal axis of the first section with the longitudinal axis of the second section when the elongate hollow body is in its maximum degree of angular displacement relative to the initial, pre-selected degree of axial alignment.
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