| 摘要 |
PURPOSE: To reduce the wear of a driving member by engaging a radial projection with the corresponding recessed part of a tank-like locking part so as to form an additional driving side surface. CONSTITUTION: A tongue-like radial projection 26 is formed on a locking body 19 in order to enhance the drive, and the radial projection 26 is integrally formed in the axial direction on the inside of the area to be engaged with the respective tank-like locking part 25 of a tool shaft 11. A corresponding recessed part 27 is formed on the bottom of the tank-like locking part 25 so as to have the corresponding form. The axial length of the recessed part 27 is set to a dimension such that the radial projection 26 of the locking body 19 never touches the axial end part of the recessed part 27 when the tool shaft 11 is axially moved within a tool receiving part 16. In this case, the side surface 28 of the radial projection 26 and the recessed part 27, which extends flatly in the radial and axial directions present in the rotating direction, forms an additional drive flank. |
