Patent ID: 7636976

Claim:
A power toothbrush comprising: a case defining two case halves with a hollow toothbrush shaft and head assembly at a distal end of the toothbrush shaft, and having mounted therein a motor with a pinion gear; a rack that is driven in a unidirectional rotation by the pinion gear and having an eccentric link that converts the unidirectional rotation of the rack into a bi-directional reciprocating linear motion; a drive shaft extending through the toothbrush shaft to the head assembly interconnected to the eccentric link that moves in the bi-directional reciprocating linear motion in response to the rotational movement of the rack; a first disk located at the head assembly, the first disk being interconnected to a distal end of the drive shaft at a point that is offset from an axis of extension of the drive shaft and remote from an axis of rotation of the first disk, the first disk being interconnected to a first brush head for rotation in a plane substantially parallel to the axis of extension of the drive shaft; a second disk located remote from the first disk and interconnected to a second brush head; and a connecting rod pivotally connected to the first disk and the second disk, the connecting rod being disposed, in its entirety, and in plan view, at a distance from the axis of extension of the drive shaft in a direction transverse thereto, so that the rotation of the first disk causes concurrent rotation of the second disk in the plane substantially parallel to the axis of extension of the drive shaft.