Power toothbrush

Abstract

A power toothbrush with a drive train that is easy to manufacture, reliable in service and that enables multiple heads or other complex design or functional elements is provided. In an illustrative embodiment, the power toothbrush includes a sealed case that encloses a motor with a pinion gear joined to an eccentric link. This eccentric link can be a circular rack having an eccentric pin that rides in a slot on a drive plate. The drive plate is joined to a push rod, typically constructed of metal that passes up a hollow toothbrush shaft through an elastomeric seal to a head assembly. The head assembly includes one or more moving disks that are each connected to generally circular brush heads, which project outwardly from the head assembly. One disk receives a bent end of the drive shaft in a hole located eccentrically to the axis of rotation. When the circular rack rotates in a single direction, it drives the shaft in a reciprocating motion that, thereby, rotates the disk in a corresponding reciprocating circular motion about its axis. Additional disks can be linked by a short connecting shaft or link to the first disk via eccentric holes—other linkages, such as mating gears between disks can be used to simultaneously drive further disks, thereby providing a multiple moving-head power toothbrush.