A Novel Dynamometer for Describing Forces and Vectors in the Long Fingers during Grip

Abstract

A new dynamometer has been designed that enables the capture of multiple grip force vectors in a single squeeze. The thumb is completely isolated in the measurement ensuring these vectors are a result of only forces produced only by the long fingers. The measured force vectors can be resolved to find the overall grip force magnitude and direction if a simple measure of grip force is desired. Alternatively, due to the ability of the dynamometer to easily measure multiple vector magnitudes and angles, the instrument lends itself well to the collection of grip data to be used as input into a hand biomechanical model. An experiment was conducted to measure the maximum grip exertions of sixteen subjects on a series of cylindrical handles and this data was used for the model. The results demonstrated that the model can be implemented and that tendon tension, when normalized by grip force, continues to increase as handle size increases even though grip force magnitudes decrease.