US Patent 9410593 Nodal spring assembly for an electronic toothbrush

A nodal-mounted spring arrangement for an electronic toothbrush includes a V-shaped spring member secured at both ends so that it can operate in out-of-phase torsion mode along the axial dimension thereof. In one embodiment, the V-shaped spring member includes two extended end regions, which extend below a longitudinal edge of the middle portion of the V-spring. The free ends of the extended portions are joined by a flat cross-piece. This “closed end” region is present at both ends of the V-spring.