Probably the most popular form of torque wrench is the click type, according to NovaTork, the purpose of a torque wrench is to tighten fasteners (nuts, bolts, studs and screws) to a specific tightness, basically to prevent vibration loosening and component warping due to uneven pressures, to reach a specified torque on a bolt without exceeding it.
A torque wrench is utilized where the tightness of screws and bolts is essential. It permits the operator to set the torque implemented to the fastener so it can be matched to the requirements for a particular application. This allows proper tension and upload all parts. A torque wrench utilizes torque as a proxy for bolt tension. The technique accepts from inaccuracy due to inconsistent or sized friction between the fastener and its mating hole. Measuring bolt tension is really what is desired, but often torque is the only practical measure that can be made.