Patent ID: 8072107

Claim:
A permanent magnet, brushless motor comprising: a housing having a proximal end, a distal end, and a longitudinal axis extending between the proximal and distal ends; a fixed motor winding located inside the housing and coaxially aligned with the longitudinal axis of the housing; first and second rotors located inside the housing and coaxially aligned with the longitudinal axis and being rotationally moveable relative to the housing, to the motor winding, and to each other, the first rotor and second rotor each having spaced magnets mounted on surfaces thereof; a coupling device located between the first rotor and the second rotor that operably couple the first rotor and the second rotor in a first position; wherein upon encountering a load, the first rotor is mechanically rotated relative to the second rotor from a first position to a second position whereby higher torque is generated; wherein in the first position, the polarity of the magnets provided on the first rotor are aligned with the magnets of opposite polarity provided on the second rotor; and wherein in the second position, the polarity of the magnets provided on the first rotor are aligned with the magnets of similar polarity provided on the second rotor.