Patent ID: 9645026
Date: 2017-05-09
CPC Classifications: B25B,B60B,G01L

Claim:
1. A tightening device comprising: a motor; a motor drive circuit that drives the motor; a drive shaft that is rotated by the motor, has a socket mounted on a tip thereof, and is configured to tighten a fastening member; a torque detector that detects a tightening torque that acts on the socket; and a control unit that controls the motor drive circuit based on a set torque set in advance and a measured torque measured by the torque detector, wherein the control unit includes a motor switching switch that switches between a first tightening process of controlling the motor drive circuit, adjusting an output of the motor after the measured torque that is measured by the torque detector has reached a preset first control start torque, such that the measured torque reaches a preset first set torque in a phased manner through repeated increases and decreases in torque, and blocking power supply to the motor when the measured torque reaches the first set torque, and a second tightening process of controlling the motor drive circuit to drive the motor at an initial output that is less than in the first tightening process, adjusting the output of the motor after the measured torque that is measured by the torque detector has reached a preset second control start torque, such that the measured torque reaches a preset second set torque in a phased manner through repeated increases and decreases in torque, and blocking power supply to the motor when the measured torque reaches the second set torque.