| 摘要 |
PROBLEM TO BE SOLVED: To provide an impact tool for realizing a detecting means of fastening torque without installing a sensor such as a stain gauge in an anvil, by using an impact mechanism of a new mechanism. SOLUTION: This impact tool includes a motor, a decelerating mechanism for decelerating torque of the motor, a hammer connected to an output part of the decelerating mechanism and the anvil rockable at a rotation angle less than 360 degrees relatively with the hammer, and drives the hammer by the motor. The size of fastening torque by the anvil is calculated by the sizes (arrows 90a, 90b, 90c and 90d) of an electric current value flowing to the motor just after impact, by impacting the hammer to the anvil by alternately driving the motor in normal rotation and reverse rotation. A driving current of the normal rotation to the motor is continuously supplied only for time t<SB>a</SB>after performing impact, and the electric current value for calculating the fastening toque is detected until the time t<SB>a</SB>passes after the impact. COPYRIGHT: (C)2011,JPO&INPIT
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