Abstract: A pneumatic power tool having a torque sensing control system is disclosed which is capable of consistently applying a precise torque to a fastener so that uniform tightening of any number of fasteners can be obtained. A torsional strain responsive transducer is mounted internally in the tool body and includes a strain gauge network mounted on a torsionally resilient portion of one of the gear cases of the drive train of the tool, the gear case being subject to a reaction component of the torque being transmitted through the drive train. The strain gauge network provides a control signal which effects energization of a solenoid-actuated air shut-off valve in the handle of the tool to automatically terminate the operation of the tool when a predetermined torque is obtained at the output spindle. The control system permits adjustment of the torque output of the tool and provides a visual readout of such output.

Abstract: A method of vacuum brazing large assemblies in an enclosed evacuated furnace with brazing material containing a gettering agent in the area of the joints to be formed, including sensing the temperature of the assembly to be brazed adjacent the joints on the exterior surface of the assembly, and shifting an additional quantity of gettering agent from a cool zone into a hot zone in the furnace as the surface temperature of the assembly approaches the brazing temperature. A furnace adapted to carry out this method is also disclosed.