Patent ID: 7422514

Claim:
A dental crown polishing apparatus comprising: a motor; a ball bearing assembly arranged around a motor shaft of the motor and equipped with a plurality of balls which rotate on its axis and circularly move around the motor shaft by receiving torque from the motor shaft; a brush assembly mounted on the outer periphery of the ball bearing assembly, equipped with brushes, that connect the plurality of balls to rotate and that have bristles in the same direction as an axial “direction of the rotation of the brush assembly”; and a tray mounted opposite and open to the brush assembly so as to direct a crown toward the brushes, wherein the motor shaft is fixedly mounted at a position offset from the center of the brush assembly, the brush assembly is able to move in orbital fashion by the rotation of the motor, the tray is able to rotate separately from the brush assembly, the rotation of the tray is not synchronous with the rotation of the brush assembly, and, dental crown polish is achieved by an orbital movement of the brushes; wherein: the brush assembly comprises power transmission means for transmitting torque to the tray; the tray comprises passive means for receiving torque from the power transmission means and rotation permitting means for permitting the tray to rotate, and the tray intermittently receives force in the direction of rotation by receiving an eccentric drive from the brush assembly through the passive means and rotates separately from the brush assembly.