The wrench functions in the same general way as an ordinary beam torque wrench. The front cover is bolted by using torque wrench. The most basic form of torque wrench consists of two beams. One benefit of the electric torque wrench is that it plugs into any wall outlet. Applying the torque to fasteners is commonly achieved using a torque wrench. Another Dr. Merritt design was the 'Slimline' torque wrench mechanism. When installing lug nuts, it is recommended to tighten them with a calibrated torque wrench. It is possible to calibrate a torque wrench in the home shop or garage. A torque wrench uses torque as a proxy for bolt tension. Ideally, the nuts (or bolts) should be tightened with a torque wrench. A slipper type torque wrench consists of a roller and cam (or similar) mechanism. The Hydraulic Torque wrench was invented in 1968 by George A. Sturdevant. A torque wrench is used where the tightness of screws and bolts is crucial. The pneumatic torque wrench was first invented in Germany in the early 1980s. In 1935, Conrad Bahr and George Pfefferle patented an adjustable ratcheting torque wrench.