| Summary: | 碩士 === 中原大學 === 工業與系統工程研究所 === 103 === Labor''s cumulatively musculoskeletal disorders caused by repetitive work are a quite serious problem in Taiwan. Current statistics of related cases show that the injuries occurred very often in the upper limbs. Therefore, to eliminate or reduce the upper limbs injuries is a very important issue. According to code 6.2.1 of the Occupational Safety and Health Act of Taiwan, employers are obligated to adopt preventive measures and have to keep these records to prevent cumulatively musculoskeletal disorders.
The purpose of this study is to analyze the whys and the wherefores of upper limbs'' cumulatively musculoskeletal disorders in chemicals manufacturing industry and, furthermore to improve the facilities or process based on the results of this study as well as propositional methods of the Occupational Safety and Health Act and ergonomic technology. There were 9 combinations (3 carry positions x 3 transport heights) of manual material handle tasks provided in our experiment. 15 male students were recruited to participate in the experiment. The Borg CR-10 Scale was used as a subjective measurement to measure perceived exertion and effort in physical work. The angles change of wrist and elbow were measured by dynamic goniometer. Five ergonomics tools such as OCRA Index, Strain Index, RULA, KIM-LHC and KIM-MHO were used to assess the risk of upper limb musculoskeletal disorders separately.
The results of subjective workload assessment indicate that the subjects felt more comfortable and exerted less force with the combination of hands carrying on long-sides of a bag and 90cm height of carrying. This result was not significant difference with carrying on short-side of a bag with transport height of 90 cm. The assessment results of using 5 ergonomics tools shows that the carrying position of short-side with transport height of 90cm had the lowest risk of musculoskeletal disorders and had good correlation with Borg CR-10. RULA and KIM-LHC are easy to use for beginner and are suitable for risk evaluation of upper limb or systemic posture, but the shortcomings are too conservative. The risk evaluation of OCRA Index and Strain Index are better than others when the differences of lower limb posture are not big enough. Strain Index can avoid unnecessary evaluation factors and analyze the cumulatively musculoskeletal disorders in the upper limbs quickly and effectively.
At the end, this study summarizes participants’ subjective and objective analysis, and recommends the combination of hand carrying on short-side of a bag with transport height of 90cm as well as equipment improvement., to reduce the risk of the cumulatively musculoskeletal disorders.
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