Abstract: A screwing spindle (1) is mounted on a frame so as to be capable of rotating about its own axis, and also to be capable of up and down movement along its axis. The spindle is rotated by a drive gear (26) via an intermediate gear (24) which is mounted on a shaft (31) which is in turn mounted on a moving support (33) which is resiliently urged towards a rest position by return means (39). The wrench device also includes detector means (45) for detecting movement of said moving support (33). When a desired torque has been reached, the moving support (33) is driven away from its rest position by said drive gear (26), and said movement is detected by said detector means (45), which are arranged to then release the jaws of the spindle.