Torque measuring device having dual range load cells

摘要

A torque measuring device having dual range load cells is provided featuring high accuracy over a large range of torque measurements. A pair of load cell assemblies act on the torque arm of a dynamometer torque balance. A compliant element is employed to connect the torque arm to a low range load cell assembly and lost motion means are provided by the high level load cell assembly. Low torques imposed on the torque balance cause only the low range load cell to be loaded. The low range load cell assembly is selected to provide high accuracy over the low torque range levels. Once a predetermined threshold torque is applied, the deflection of the compliant element permits the torque arm to engage the high level load cell assembly. Torques beyond the threshold level are determined by summing the measured torques of both load cell assemblies. Several embodiments are described which disclose various means for providing a compliant linkage for the low range load cell assembly and for providing a lost motion coupling for the high range load cell assembly.