Research On Portable Structure Of Express Packaging Box Based On Human Factors

Portable structures of express packaging boxeses can asswast operator when they perform manual material handling operations.In China,the manual material handling operation intensity of the express delivery industry is very high,and the lack of portable structures and unreasonable portable structures of express packaging boxes will increase the operator’s workload and cause related occupational musculoskeletal dwaseases.Therefore,it was necessary to use the human factors method to assess the effect of on human physiological load in manual material handle.The methods used in thwas study include psychophysical,physiologic and biomechanical.In this study,the operator’s work ability,physiological load and joint torque have been researched during express packaging boxeses lifting and carrying tasks。The influence of the portable structures of express packaging boxeses on the operator’s work ability（maximum acceptable weight）,subjective fatigue rating and the risk of lifting were analyzed.And the effects of both the express packaging boxeses length and the portable structure height positions on the human physiological load characterized by heart rate change and surface electromyography were studied.The human body multi-rigid body model was used to simulate the force of the upper limb when the operator performs the courier operation.And the optimization of the express packaging boxes size and the portable structure design was proposed,according to the law of upper limb strength and operator’s habits.According to the human factors guidance to handle tool design,the portable structure’s size and shape were optimized and evaluated using a subjective score table.The research shows that when using different portable structures,there were differences in the operator’s work ability,and there were differences in the lifting and carrying tasks.When operators using the hand hole structure in the lifting task,they had the highest work ability.When operators using the groove structure in the carrying task,they had the highest work ability.We can know that reasonable portable structures can reduce the operator’s workload.The length of express packaging boxeses and the height of the portable structures could affect the overall physiological load and muscle load of the operators.The muscle load of the erector spinae and biceps was significantly affected by the height of the portable structures,the muscle load of the deltoid was significantly affected by the length of express packaging boxes,both these factors have an effect on the trapezius muscle load.According to biomechanical analysis,the lumbar vertebrae at L₅/S₁decreased with the portable structures positions.Abduction torque of shoulder muscle increases with the length of the express packaging boxes.Elbow buckling torque increases with the portable structure positions.According to the above conclusions,combined with the operator’s habit of carrying the express packaging boxeses,the recommended design sizes were about 471 mm length,371 mm width,and the height was no more than 319 mm.The portable structures should at both the boxes bottom and H/6 above the centerline of boxes’two sides.The groove handle’s depth should be the objects’front two knuckles’length,and the hole handle on the box sides should be folded by the triangular prism.