Wrench provided with an alternating current drive motor

摘要

PCT No. PCT/DE81/00230 Sec. 371 Date Jul. 23, 1982 Sec. 102(e) Date Jul. 23, 1982 PCT Filed Dec. 18, 1981 PCT Pub. No. WO82/02297 PCT Pub. Date Jul. 8, 1982.The invention relates to a wrench provided with an alternating current drive motor whose peculiarity is a medium frequency asynchronous motor (2) which is used as the drive motor with an associated device (7) for a frequency switching from the medium frequency to a lower line frequency. The mentioned device (7) is connected with a cycle control (8) from which it is switched off as soon as it receives the signal by means of a connected torque sensor (5) about the occurence of the setting moment on the screw joint made with the wrench.