Method for tightening a bolt to exert a predetermined tension force by monitoring bolt elongation while the bolt is being installed

The method of tightening a bolt by a hand-held power-driven wrench to exert a predetermined tension force comprising the steps of:

• providing a hand-held power-driven wrench having a power-driven rotatable shaft extending out of the front engageable with a drive socket for tightening a bolt,
• providing a passage extending through said wrench including an axial bore passing through said shaft and opening at the front end of said shaft,
• providing an ultrasonic transducer adapted to engage the top end of the bolt,
• positioning said transducer within said drive socket near the open end of said shaft,
• engaging the drive socket with the bolt to be driven,
• urging the transducer against the top of the bolt while continuing to engage the drive socket with the bolt,
• regularly repeatedly generating electrical pulse signals and feeding such generated electrical pulse signals forward through said passage and through said axial bore to the transducer for conversion into ultrasonic energy pulses for transmission into the top end of the bolt to travel through the bolt to the other end to be reflected to travel back to the top end,
• receiving the returning ultrasonic energy pulses with said transducer for conversion into returning electrical pulse signals fed back through said axial bore and back through said passage,
• using the generated electrical pulse signals and the returning electrical pulse signals for monitoring the length of the bolt,
• applying power for turning said shaft and drive socket for tightening the bolt,
• allowing the transducer to rotate with the top end of the bolt against which it is being urged as the bolt is being tightened,
• continuing to feed such generated electrical pulse signals to the rotating transducer,
• continuing using the generated electrical pulse signals and the returning electrical pulse signals for monitoring the increase in length of the bolt, and
• discontinuing the tightening of the bolt when its increase in length has reached an amount corresponding to said predetermined tension force.

The method of tightening a bolt to exert a predetermined tension force comprising the steps of:

• providing a rotatable drive socket capable of being engaged with the head of a bolt for tightening the bolt,
• providing a ultrasonic transducer adapted to engage the top surface of the bolt head,
• positioning the transducer within the drive socket,
• engaging said drive socket with the head of the bolt to be tightened,
• urging the transducer against the top surface of the bolt head while continuing to engage said drive socket with the bolt head,
• feeding electrical pulse signals to the transducer while continuing to urge the transducer against the top surface of the bolt head and while also continuing to engage the drive socket with the bolt head for causing the transducer to transmit ultrasonic energy into the top surface and through the bolt to the other end to be reflected for returning back to the top surface to be received by the transducer for conversion into received electrical signals,
• turning said drive socket for turning the bolt head being engaged thereby for tightening the bolt while feeding electrical pulse signals to the transducer while also continuing to urge the transducer against the top surface of the bolt head,
• using the electrical signals being fed and received for monitoring the length of the bolt, and
• discontinuing the turning of said drive socket when the increase in length of the bolt has reached an amount corresponding to said predetermined tension force.