US Patent 7503228 Electronic torque spanner

An electronic torque spanner includes a driving portion having a driving head for engaging a screwing object, and having a connecting segment, and a handle having a connecting space defined by the inner peripheral surface at the opening end of the handle. The connecting segment is engaged with the connecting space. A slot is formed in the connecting segment and a bottom surface defined at the end of the connecting segment. A strain gauge is installed in the bottom surface and crossed over the slot for measuring the torque in the operation of the spanner. A display unit is installed in the handle and electrically connected to the strain gauge for setting, displaying, and warning with signal.