Effect of handle design for cylinder trolleys.

An experiment was carried out to investigate the effects of handle design on the biomechanical stresses imposed in the use of a cylinder trolley. Nine combinations of handle orientations (35 degrees, 50 degrees, 70 degrees)and handle length (1.0, 1.1, 1.2 m) were tested for the initial starting off phase and the steady moving phase. Two weights of cylinder (19 and 37 kg) were used. Measurements were made of wrist angle, elbow flexion, force at the feet and subjective ratings of effort, discomfort and stability as well as the angle at which the trolley was tilted. The biomechanical loads on the spine and joints of the arm were also calculated. High stresses at the elbow and considerable wrist deviations were found to occur during the starting phase. The elbow stresses were significantly affected by the design of the trolley handle, as was the degree to which the trolley was tilted while moving forward with load. For starting, the best configuration proved to be a 35 degrees handle angle and a 1.0 m handle length. The results were, however, less clear in determining the best configuration for pushing the trolley forwards.