Investigation of common insertion hand postures and directions and determination of the voluntarily maximal and preferred insertion forces in automotive assembly tasks

Abstract

The aim of this study was to investigate common insertion hand postures and directions (study 1) and determine the maximal and preferred insertion forces (study 2) for assembly workers. Video analyses were conducted to investigate the insertion hand posture and direction according to assembly materials. The results of the video analyses revealed that the left and right hands used five and six types of hand postures, respectively, with the maximum frequency, and this accounted for 86.7% and 81.4% of the postures, respectively. Forty male subjects participated in a psychophysical methodology test in which they were asked to perform insertion tasks by selecting the magnitudes such that the maximal acceptable forces (MAFs) and preferred forces (PFs) could be determined. The results indicated that hand posture, insertion direction, and age significantly affected MAFs. Furthermore, hand posture, insertion direction, and age significantly affected PFs. The insertion force should be considered in the task design phase, especially hand posture, insertion direction, and age.

Mapping the Accidents and Unsafe Conditions of Workers in the Automotive Sector

“…This may be associated with a larger number of employees in this occupation in relation to other occupations of the companies. In addition to the exposure of these workers to high demand of physical effort, with repetitive, monotonous, manual work, with load movement (Lee and Jung, 2020), by imposing penalizing postures, with overhead work, rotation and flexion of the trunk (Hermans et al, 1999;Dalle Mura and Dini, 2019). And with complexity of the operator selection process in each assembly task (Zhu et al, 2008) and industrial physical arrangement of the production line (Comper et al, 2017).…”

“…The second most reported type was contusion or crushing, which is related to the intense movement of cargo and materials, use of machinery, and storage and stockpiling activities (Lee and Jung, 2020). When considering the occupations with the highest occupational accident rates and the causative agents in both economic activities, it is possible to notice that the extremities of the upper limbs of these workers are the most used in the work activities.…”

“…The automotive industry requires workers to perform many types of repetitive assembly tasks, which use excessive force. It requires a high level of quality work to meet customer demands (Doiro et al, 2017;Sá et al, 2019;Lee and Jung, 2020;Sales et al, 2022), often with the help of lean tools (Silva et al, 2020;Rodrigues et al, 2019).…”