| 摘要 |
PROBLEM TO BE SOLVED: To provide a screw member fastening tool having temporary screw fastening function.SOLUTION: An electric driver 1 comprises a bit holder 18 for fixing and holding a driver bit 16, a drive motor 32 for rotationally driving the bit holder, and a control unit 30 for controlling drive of the drive motor. In the electric driver 1, the control unit 30 controls the drive motor 32 so as to normally rotate the bit holder 18 by only a first rotation amount, and thereafter, to automatically reverse-rotate the bit holder by a second rotation amount smaller than the first rotation amount. The control unit 30 controls a drive time for the drive motor 32 thereby controlling the rotation amount of the bit holder 32. If a normal rotation drive time (first time) is so set that the first rotation amount of normal rotation drive becomes the amount such that a screw does not seat on a fastened member, the screw can be temporarily fastened even if a rosette or the like which cannot be easily loosened upon fastening of the screw is used.SELECTED DRAWING: Figure 4 |
