Patent ID: 7493669

Claim:
A power toothbrush, comprising: a toothbrush housing; a driving assembly which includes a motor having an armature which rotates back and forth through a distance; an output assembly which includes a brushhead; a coupling assembly which connects the armature to the output assembly, wherein the coupling assembly includes a torsion member having a node point therealong, the torsion member having first and second opposing ends and a longitudinal axis, the motor armature in operation rotating the first end of the torsion member in one rotational direction about its longitudinal axis, and wherein the second end of the torsion member rotates the output assembly in the opposing rotational direction, and wherein the torsion member is substantially stiff in all directions except for a torsional direction; and support elements connected between the driving assembly and the housing and between the output assembly and the housing, wherein the driving assembly operates in such a mode that the brushhead moves in the opposite rotational direction from the driving assembly and wherein the moments of inertia of the output assembly and the driving assembly, respectively, oppose each other, thereby substantially preventing coupling of vibrations to the housing.