ELECTRONIC TORQUE WRENCH AND OVERSHOOT COMPENSATION CIRCUIT THEREFOR

摘要

A torque wrench (10) has a battery-powered sensing circuit which produces a torque signal (55) proportional to the level of the torque applied. A reference signal (56) corresponding to a predetermined torque level is subtracted from the torque signal to produce a difference signal (57) which is, in turn, compared with a compensation signal (58) which is proportional to the rate of change of the torque signal (55) and is produced by differentiating the torque signal. When the value of the difference signal (57) exceeds the value of the compensation signal (58), an indicator is triggered to produce a tactile indication, the indication being produced prior to the time that the torque signal reaches the reference level (56) by a predetermined time period.