Abstract: A torque wrench according to the invention has a rigid elongated body having a tool end adapted to be rotationally fixed to a part to which a predetermined desired torque is to be applied and an opposite handle end. Transducers including strain gauges connected between the tool end and the body generate an actual-value output corresponding to the actual torque being applied by the wrench to the part rotationally coupled to the tool end. A display connected to the transducers reads out torque and an input device generates a desired-value output corresponding to the desired torque to be applied by the wrench to the part rotationally coupled to the tool end. A first comparator connected to the transducer and input device compares the actual-value and desired-value signals and generates an alarm signal when the actual torque is substantially the same as the desired torque. In accordance with this invention a second comparator compared the actual torque with a relatively low threshold torque.

Abstract: An electronic torque wrench has a rigid metallic sleeve of generally regular section extending along a tool axis and having a front end and an opposite handle end and a holder integrally formed with a flat rear part, a socket-like front part, and a flat web part interconnecting the rear and front parts. The flat rear part extends generally diametrically of the axis in the front end of the sleeve and has a pair of outer edges radially outwardly engaging the sleeve in surface contact. The front socket part is adapted to receive a wrench fitting engageable with the element to be torqued and is wholly out of contact with the sleeve. The flat intermediate web part interconnecting the front and rear parts extends diametrically of the axis and generally perpendicular to the rear part, has a pair of oppositely directed faces, and is wholly out of contact with the sleeve. This web part is substantially only capable of flexing perpendicular to itself and parallel to the rear part.