Patent ID: 6053080
Filing Date: 2000-04-25
Classification: B25B

Abstract:
A device for tightening a bolt or a nut comprising a socket for tightening up the bolt or the nut, a socket drive motor for rotating the socket, and a controller for deenergizing the socket drive motor when tightening torque not smaller than a predetermined value acts on the socket, the bolt or nut tightening device being characterized in that the device comprises:power transmission means for coupling the socket drive motor to the socket for power transmission,a clutch incorporated in the power transmission means for selectively effecting or interrupting power transmission from the socket drive motor to the socket by a sliding movement, andclutch control means for selectively moving the clutch to an engaged position or a disengaged position,the clutch being movable to the disengaged position by the clutch control means after the socket drive motor is deenergized, whereby residual torque delivered by the motor to the bolt or the nut is removed to preclude biting engagement of the socket with the bolt or nut.