| 摘要 |
A device for controlling downhole tools rotates in predefined increments and comprises three separate parts each with a profiled surface. Relative rotation occurs between interengaging surfaces 28, 30 and is caused by axial sliding of a separate internal sleeve or piston 26 that has its own profiled surface (36, figure 3). In the preferred embodiment, all the profiled surfaces are asymmetric toothed profiles, formed at the end of a cylindrical body. Two of the cylinders have the same external diameter and interengage, but the teeth of one are wider and extend inwardly to engage with the teeth on the internal sleeve. Axial movement of this sleeve disengages and relatively rotates the two principal cylinders, which may be biased towards each other. The device may be used to select and switch control valves downhole. |
