Abstract: An electric impact tightening tool in which the rotation of an output section of an electric motor is transmitted to an impact generation section (P) and impact force generated in the impact generation section (P) causes a main shaft (107) to produce strong torque, where the electric motor is an outer rotor electric motor (M). The outer rotor electric motor (M) has low-speed, high-torque characteristics. In the tool, the impact generation section (P) and a rotor flange (61) at the forward end of the motor (M) are adapted to rotate integrally. The electric impact tightening tool is small sized and lightweight, produces low reaction force, and has durability.

Abstract: An impact wrench including a hammer and an anvil to which impacts are imparted by the hammer, the impact wrench comprising a pair of sensors located at a stationary section of the wrench wherein the sensors are electrically arranged so as to have different phases, the sensors being to detect the rebounds occurring on the anvil, a second sensor adapted to detect an angular displacement of the anvil from a time when the rebounds detected by the first sensors exceed a predetermined value, and means for stopping the motor.