Tightening torque measuring unit and torque indicating tightening device

A tightening torque measuring unit for measuring the tightening torque of a bolt or nut tightening device,

• the bolt or nut tightening device having a device main body comprising a first output shaft and a second output shaft which are rotatable in directions opposite to each other and coaxially arranged,
• the tightening torque measuring unit having an inner shaft connectable to the first output shaft of the device main body and an outer shaft connectable to the second output shaft, the inner shaft being provided at an outer end thereof with one of a tightening socket and a reaction force receiver, the outer shaft being provided at an outer end thereof with the other of the socket and the receiver, the outer shaft having a strain gauge thereon,
• the tightening torque measuring unit further comprising a circuit board for converting an amount of strain detected by the strain gauge into a corresponding tightening torque value and an indicator for indicating the tightening torque value, and
• the tightening torque measuring unit being removably connectable to the device main body.