Method for detecting if a fastener is already tightened

A tightening tool comprising:

• a pulse mechanism;
• a motor;
• a drive member;
• a measurement unit;
• and
• a processing unit connected to the measurement unit,
• wherein the motor is configured to drive the drive member,
• wherein the pulse mechanism is configured to rotate along with the drive member,
• wherein the measurement unit is configured to measure at least one of an angle, an applied torque, pulse, and time, and
• wherein the processing unit is configured to control the tightening tool to perform operations comprising:
• accelerating rotational parts of the tightening tool;
• limiting a rotational speed of the rotational parts to a first rotational threshold value in revolutions per minute during an initial tightening phase, the first rotational threshold value being set to be in a range of 20% to 80% of a second rotational threshold value in revolutions per minute needed in a secondary tightening phase to provide a target fastening value for a fastener;
• detecting whether a pulse occurs during the initial tightening phase, the initial tightening phase being measured from a moment when the rotational parts are accelerated;
• and
• accelerating the rotational parts of the tightening tool up to the second rotational threshold value if no pulse is detected.