A system for the measurement of grip forces and applied moments during hand tool use

Quantification of the forces applied with or by hand tools can be a difficult but important component of an ergonomic evaluation. This paper describes a device for measuring gripping forces and the moments generated by a hand tool. Laboratory characterization indicated that the device had good linearity (r2 = 0.999) with minimal hysteresis or creep. The working range exceeds 700N for gripping forces, and 28 and 16Nm for the two applied moment axes. The device, configured as a boning knife, was sensitive to differences in grip forces and applied moments in a simulated meat cutting task requiring distinct levels of precision. Significant individual variation in the "efficiency" of grip force was also observed. The system design is flexible, allowing for additional tool configurations.