| 摘要 |
A toothbrush has an elongated handle and a brush head supported at one end of the handle for a limited pivotal movement between opposed arms of a yoke structure, i.e., by torsion bar support elements joining the support arms to opposed edges of the brush head. A further resilient element may be employed between the brush head and the proximal end of the handle to provide additional resistance to pivotal movement. Preferably the further resilient element is designed to have an increased spring constant as the brush head is pivoted progressively farther from its normal position in substantially coplanar relation with the handle and thus acts as an effective stop limiting maximum pivotal movement of the head. The base of the brush head which supports the brush bristles, the handle, yoke and resilient support elements may be integrally molded from a single mass of synthetic resin material and at least the resilient elements are preferably formed from polypropylene, or a polymeric material having substantially the same physical characteristics.
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