Bolt or nut tightening device having reaction force receiving member

摘要

A bolt or nut tightening device comprising a tightening socket ( 4 ) and a reaction force receiving member ( 5 ), the tightening socket ( 4 ) being rotatingly drivable upon a speed reduction by a motor ( 2 ) and a reduction mechanism ( 3 ) which are incorporated in the device, the motor ( 2 ) being coupled to a controller ( 7 ), the controller ( 7 ) being operable to deenergize the motor ( 2 ) in response to a tightening completion signal of detecting means ( 70 ) for detecting the completion of tightening of a bolt or nut and to reversely rotate the motor ( 2 ) only for a moment upon lapse of a predetermined period of time taken for inertial rotation of the motor ( 2 ) to reduce to an extent neglectable for the reverse rotation of the motor ( 2 ) after the deenergization, whereby the propping action of the reaction force receiving member ( 5 ) is nullified.