| 摘要 |
It is an object of the invention to provide an electric screwdriver that can efficiently transmit torque for tightening a screw and stop the torque transmission. A representative screwdriver may include a motor, first and second rotating members, a tool, a torque transmission spring and a torque transmission releasing device. The torque transmission spring transmits the rotating torque of the motor from the first rotating member to the second rotating member in order to drive the tool by closely winding around the first rotating member and the second rotating member when the motor drivingly rotates the first rotating member in a predetermined rotating direction. Further, the torque transmission releasing device moves in the axial direction of the first rotating member or the second rotating member in response to the screw-tightening torque. By such movement, the torque transmission releasing device releases the close winding of the torque transmission spring around at least one of the first rotating member and the second rotating member and releases the transmission of the rotating torque of the motor to the tool.
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