Patent ID: 6837315

Claim:
A rotary steerable drilling tool, comprising: a tool collar comprising an interior, an upper end and a lower end, a bit shaft comprising an exterior surface, an upper end and a lower ends the bit shaft being supported within the tool collar for pivotal movement about a fixed position along the bit shaft; a variable bit shaft angulating mechanism, located within the interior of the tool collar, comprising a motor, an offset mandrel having an upper end and a lower end and a variable offset coupling, having an upper end and a lower end, the motor attached to the upper end of the offset mandrel and adapted to rotate the offset mandrel, the upper end of variable offset coupling being uncoupleably attached to an offset location of the lower end of the offset mandrel, and the upper end of the bit shaft being rotatably coupled to the variable offset coupling; a torque transmitting coupling adapted to transmit torque from the tool collar to the bit shaft at the fixed position along the bit shaft; and a seal system adapted to seal between the lower end of the collar and the bit shaft.