US Patent 7721826 Downhole jack assembly sensor

In one aspect of the invention, a drill string comprises a drill bit with a body intermediate a shank and a working face, and the working face comprises at least one cutting element. A jack assembly is disposed within the drill bit body and comprises a jack element disposed on a distal end of the assembly. The jack element substantially protrudes from the working face and is adapted to move with respect to the bit body. At least one position feedback sensor is disposed proximate the jack assembly and is adapted to detect a position and/or orientation of the jack element.