Abstract

A torsion wrench includes a tubular casing, a drive unit pivoted to the casing and adapted to engage a workpiece, a knocker for generating an alarm sound when torsion force that is applied by the drive unit on the workpiece reaches a predetermined torsion force limit, a biasing unit for biasing the knocker toward the drive unit, and an adjusting unit for adjusting initial biasing force of the biasing unit. The biasing unit includes a push piece and a spring disposed between the push piece and the knocker. The adjusting unit includes a tubular handle member which has a connecting end sleeved rotatably on one end of the casing, and a push rod unit having a first end portion extending into the handle member and a second end portion extending into the casing and connected to the push piece. Rotation of the handle member results in axial movement of the push rod unit in the casing. A torsion force detecting unit includes a sensor unit for generating an electrical signal corresponding to position of the push piece in the casing, a converter circuit for converting the electrical signal into a digital reading of the predetermined torsion force limit, and a display unit for displaying the digital reading thereon.