PROBLEM TO BE SOLVED: To provide a shift operation mechanism capable of mechanically changing the speed of a transmission device corresponding to a manual operation while attaining the simplified structure of a steering part and preventing the intrusion of impurities including dust inside the steering part.SOLUTION: The shift operation mechanism includes: a shift operation shaft supported on the steering part rotatably around axis astride the inside and outside of the steering part a shift operation member operably connected to the shift operation shaft inside the steering part so that the shift operation shaft is rotated around the axis corresponding to a manual operation and a link mechanism, which operably connects the shift operation shaft to the transmission device outside the steering part so that the transmission device is operated according to the rotation around the axis of the shift operation shaft.COPYRIGHT: (C)2011,JPO&INPIT【課題】操縦部の構造簡略化及び外部から操縦部内への塵等の不純物の侵入防止を図りつつ、人為操作に応じて変速装置を機械的に変速させ得る変速操作機構を提供する。【解決手段】操縦部の内外に跨った状態で軸線回り回転可能に前記操縦部に支持された変速操作軸と、人為操作に応じて前記変速操作軸を軸線回りに回転させるように前記操縦部内において前記変速操作軸に作動連結された変速操作部材と、前記変速操作軸の軸線回りの回転に応じて前記変速装置を作動させるように前記操縦部の外方において前記変速操作軸を前記変速装置に作動連結するリンク機構と備える。【選択図】図8
