Comparison of required operating forces between floor-based and overhead-mounted patient lifting devices

This study investigated the differences in required push, pull and rotating forces for moving fully loaded, floor-based and overhead-mounted full body patient lifting devices with simulated patients of varying weight on a floor of optimal design (i.e. level vinyl tile over concrete). A single person operated the lifting devices for all of the tests. Eighteen male and female volunteer participants, ranging in weight from 51 to 146 kg, acted as patients during the lifting tests. For each test, the simulated patients were pushed and pulled for 3.7 linear metres and were rotated while sitting in the lift slings. Force measurements were acquired using two single axis dynamometers affixed to the lifting devices. Results revealed that, in general, operator input force and torque increased with patient weight category and floor-based lifts required greater force and torque compared to the overhead-mounted lift. Comparison of the required forces with published force limits reveals that the required push and pull force from the various patient lift systems, across all weight categories, were generally acceptable to 90% of the female population. The required forces for these patient transfer tasks, however, could exceed maximum acceptable force limits if the floor surfaces were less than ideal, such as floors composed of carpet, wood, or inclined surfaces. Additional research is needed to assess these conditions.