Force distribution at hand/handle coupling. The effect of handle type

Handle location and geometry play an important role in container design and effectiveness. An ideal handle position and angle should minimize stress at L5/S1 and minimize average grip pressure on the two hands with force distributed evenly on both hands. Handles in such a position will be most comfortable for performing a MMH task and reduce the likelihood of compressive injuries on the lumbar spine. Most of the published research on container handles have used the psychophysical, biomechanical, and/or physiological methods to determine handle effectiveness. The force distribution at the exact point of energy transfer, namely the hand/handle interface has rarely been addressed by the scientific community. The intent of this study was to determine the force distribution at the hand/handle interface and use the same to compare the effectiveness of various handle types, positions, and angles. Six factors were tested in this experiment using a fractional factorial design. The pressure at the interface was measured using a number of force sensing resistors' (FSRs) in each hand. The results indicate handle positions 2/2, 8/8, and 3/7 to be far superior to position 6/8. The average pressure at the FSR sites appear to be the least at handle angles of 0 degree. Further, the force distribution for the cut-out handle appears to be more uniform than that for the cylindrical handle (circular cross-section). Based on these findings recommendations are made for container designer.