US Patent 7122921 Top loading internal assembly for a power toothbrush

A first aspect of the disclosure concerns a driving assembly for a power toothbrush which includes a drive member, specifically an E-core electromagnet, a driven member which is responsive to the action of the drive member and a workpiece mounted on the distal end of the driven member. The drive assembly includes an interface registration member, to one end surface portion of which is secured the end face of E-core electromagnet, another portion of which is configured to produce a selected registration of the driven member and the driving assembly, and still another portion of which is configured to produce a selected registration of the interface member relative to the handle of the toothbrush.