Patent attributes
Tightening tools is provided with a pair of clutch members disposed between a motor and a tool bit. The pair of clutch members is provided with a first engaging portion and a second engaging portion. The first engaging portion is constructed so as to disengage the pair of clutch members when the torque applied to the tool bit is equal to or above a first predetermined value. The second engaging portion does not engage the pair of clutch members while the first engaging portion engages the pair of clutch members and the second engaging portion engages the pair of clutch members after the first engaging portion disengages the pair of clutch members. The second engaging portion is constructed so as to disengage the pair of clutch members when the torque applied to the tool bit is equal to or above a second predetermined value. The second predetermined value may be different from the first predetermined value.