PROBLEM TO BE SOLVED: To provide a dental handpiece where the reciprocating inversion angle of a cutting tool is enlarged (for instance, to an extent of 100°-135°).SOLUTION: The dental handpiece is structured as follows: a reciprocating inversion mechanism 4 includes an almost spherical inversion axis 40 pivoted between input- and output-side rotary shafts 361, 362 and having input- and output-side guide grooves 401, 402, a spherical concave part 41 set up to the rotary shaft 361 and engaged with one semispherical side of the inversion axis 40, a guide pin 411 engaged with the guide groove 401, a spherical concave part 42 set up to the rotary shaft 362 at the output side and engaged with another semispherical surface side of the inversion axis 40, and a guide pin 421 engaged with a guide groove 402 and is structured inside a grip 3. The respective guide grooves 401, 402 of the inversion axis 40 can be formed so as to have an optional depth using the whole of the spherical body of the inversion axis 40, and the setting area of the angle of the respective guide pins 411, 421 set in accordance with the inversion angle of the cutting tool, is widen.COPYRIGHT: (C)2013,JPO&INPIT【課題】切削工具の往復反転角度を(例えば100°~135°程度まで)大きくする。【解決手段】往復反転機構4は、入力側、出力側の回転軸361、362間に軸支され、入力側、出力側のガイド溝401、402を有する略球体状の反転軸40と、回転軸361に設けられ、反転軸40の一方の半球面側に係合される球面状凹部41及びガイド溝401に係合されるガイドピン411と、出力側の回転軸362に設けられ、反転軸40の他方の半球面側に係合される球面状凹部42及びガイド溝402に係合されるガイドピン421とを備えてグリップ3内部に構成され、反転軸40の各ガイド溝401、402を反転軸40の球体全体を使って任意の深さに形成可能とし、切削工具の反転角度に応じて設定される各ガイドピン411、421の角度の設定領域を拡大した。【選択図】図1
