A toothbrush having a head which carries a dental cleaning tool, and a grip handle, the head and handle being disposed along a longitudinal head-handle axis, the toothbrush having a resiliently flexible structure which can resiliently bend under the action of toothbrushing pressure and having adjustment means comprising a longitudinally moveable stiffening member which can be moved longitudinally into greater or lesser engagement with the resiliently flexible structure.
1. A toothbrush which has a head which carries a dental cleaning tool, and a grip handle, the head and handle being along a longitudinal head-handle direction, the implement has a resiliently flexible structure, which comprises a region of “U” or “V” shaped folds in the material of the toothbrush, situated in its handle or between its head and its handle, which can resiliently bend under the action of pressure experienced by the head during toothbrushing, wherein the toothbrush has adjustment means by which the user may alter the flexibility of the resiliently flexible structure between less and more flexible, the adjustment means comprising a longitudinally moveable stiffening member which is mounted externally on the flexible structure or on the handle or on the neck of the toothbrush longitudinally adjacent to the resiliently flexible structure and which can be moved longitudinally into greater or lesser engagement with the resiliently flexible structure, the resiliently flexible structure having one or more guides in its external surface and the stiffening member has one or more parts which can engage with the one or more guides and which can ride longitudinally along the one or more guide.
2. A toothbrush according to claim 1 wherein the resiliently flexible structure comprises a composite region of one or more relatively more flexible elastomer parts and one or more relatively less flexible plastic material parts.
3. A toothbrush according to claim 2 wherein the composite flexible structure comprises a region of “U” or “V” shaped folds in the material of the toothbrush, with an elastomer material in the concavity or “bite” between the limbs of the folds.
4. A toothbrush according to claim 1 wherein the stiffening member comprises one or more longitudinally extending arms, extending in the direction toward the head of the toothbrush, which can engage with the flexible structure.
5. A toothbrush according to claim 1 wherein the stiffening member is longitudinally slideable relative to the flexible structure.
6. A toothbrush according to claim 5 wherein a longitudinally slideable stiffening member is on each side of the toothbrush, the members being linked together to enable them to move together slideably along the toothbrush.
7. A toothbrush according to claim 1 wherein the resiliently flexible structure is a region of “U” shaped folds, the fold axes of the folds being aligned perpendicular or at an acute angle to the longitudinal axis and to the bristle direction; there is an elastomer material in the bite between the limbs of the folds; situated on the handle of the toothbrush is a longitudinally moveable slider; the flexible structure has one or more external longitudinal grooves; the stiffening member comprises one or more arms, which extends longitudinally toward the toothbrush head when the slider is on the handle, and the one or more arms engages with the one or more grooves when the slider is moved longitudinally toward the head.
8. A toothbrush according to claim 7 wherein the one or more arm is progressively moveable toward the toothbrush head to thereby cause the one or more arm to cross a progressively greater number of limbs of the “U” or “V” shaped folds, and to bridge a progressively greater number of the “bites” between adjacent limbs.
9. A toothbrush according to claim 1 wherein the stiffening member is moveable internally within the flexible structure.
10. A toothbrush according to claim 9 wherein the stiffening member is longitudinally moveable by a whole or partial screw thread action.