The hazard of occupational operation of handy manhole/handhole covers lifter and ergonomical design
T. Y. Kam
|關鍵字:||人孔;手孔;肌肉骨骼傷害;動作姿勢分析;manhole;handhole;musculoskeletal Disorders;postural analysis|
問卷內容包括基本資料、簡易式啟閉器操作性能、及身體酸痛症狀等部份，計完成396份問卷回收與分析。動作分析研究選定八名受測者，利用數位攝影機分別拍攝受測人員啟閉蓋板之實際作業姿勢（包括1.長柄、短柄及人因式啟閉器，2.人孔及手孔蓋板，3.作業方法：兩人平拉及推拉方式），繼而利用REBA（Rapid Entire Body Assessment）方法進行動作分析，以瞭解啟閉作業姿勢缺失，並提出啟閉器改良之建議，降低人員肌肉骨骼傷害風險。研究結果顯示：依蓋板類型，啟閉人孔蓋板作業姿勢之危害程度高於手孔蓋板，其中TL-90雙層人孔蓋之啟閉較單層人孔蓋危害高；利用長柄或短柄啟閉器進行啟閉，視人員身高差距，呈現不同危害姿勢；啟閉作業方法中，則以推拉方式造成之危害動作較多。
在消除簡易式啟閉器危害方面，則充分利用研究結果所得進行 ― 簡易式人/手孔蓋板啟閉器之人因工程設計，設計成品經試用、分析及現場啟閉作業驗證等連串程序。結果顯示：人因式簡易啟閉器可有效減輕人員啟閉蓋板時之施/受力負荷，且啟閉作業過程中人員身軀多能保持直立姿勢，而不需過度彎腰曲膝，確實符合人/手孔作業人員操作感受角度出發之親近性設計手工具。|
The manhole/handhole operations will become more popular and significantly important as if has a tendency to place electric wire and telecommunication cable underground in the near future. The types of work-related injuries are quite different when compared with that of the aerial cable operations. The manhole/handhole iron covers need to be opened and removed with opening/closing devices before assigned task is performed. The workers’ physical loads due to the weight of manhole/handhole covers and the awkward working postures have significant effects on the work-related injuries. The researches of workers’ musculoskeletal disorders on manhole/handhole operations were few in the literature. In this study, a questionnaire and postural analysis method were designed and performed to explore the risk issues during opening /closing operations by the workers. The improvements of work method, hand tool design and light-weight design of manhole/handhole covers were suggested. The D-8 video recorder was used in the real road facilities to record 8 subjects’ cover-opening operations. There were several variables were considered in this study: short/long arm devices for cover-opening, manhole/handhole, and methods of opening. Then, the REBA (Rapid Entire Body Assessment) postural analysis method was applied in this study. The results showed that the operational risk due to postures from manhole cover-opening was higher than that from handhole cover-opening. In addition, the risk to open TL-90 manhole cover was higher than Simple-layer manhole cover. Comparing the short-arm opening device with the long one, it was found the anthropometric data were significant in the study. Among the opening methods, pulling/pushing method produced the high risk. Regarding the elimination of the hazards induced by the handy manhole/handhole covers lifter, the design program uses the results of study to perform the ergonomical design of handy manhole/handhole covers lifter, The designed product then went through a series of testing and real practical opening /closing operations. As a result, it has shown that the ergonomical handy covers lifter can efficiently reduce the pulling /pushing force when the workers open /close the manhole/handhole covers, with their bodies still keeping the erect postures in the whole procedure, and without leading to excessive motions of bending workers’ lumbar and knees. Furthermore, the workers’ feeling of opening /closing operations has also indicated that the friendly design devices can fit the workers’ bodies more properly.