A stepping motor comprising a rotor having magnetic poles on the peripheral surface thereof at a predetermined pitch, first and second stator yoke units each having pole teeth at the predetermined pitch and disposed with deviation of 1/4 pitch therebetween relative to the rotor, and a coil for exciting...http://www.google.ca/patents/US4972109?utm_source=gb-gplus-sharePatent US4972109 - Stepping motor
