US Patent 8418302 Tooth brush motor

A motorized toothbrush includes a shaft, a tooth brush mounted to a distal end of the shaft, a coil mounted to and surrounding the shaft, a first magnet adjacent to a periphery of the coil, and a second magnet adjacent to the periphery of the coil and on an opposite side of the coil with respect to the first magnet. Passing a current through the coil causes the shaft to rotate alternately clockwise and counterclockwise.