An Ergonomic Approach to Oyster Knife Design and Evaluation

• Main Authors: Guogang Lyu, 呂國綱
• Other Authors: Man-lai You
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/45490047432097170445

碩士 === 雲林科技大學 === 工業設計系碩士班 === 99 === Oyster farming already has a history of more than 300 years in Taiwan. Inevitably, oyster plays an important role in the development of the local economy as well as the dietary culture of Taiwan. According to the local dietary customs, the collected oysters usually have to be shucked manually. Therefore, the design of the shucking tool greatly influences whether the safety and wellbeing of the oyster shucking workers. This thesis underwent a thorough research on the design of oyster shacking knives and its improvement. This study consisted of three phases: 1) The investigation of oyster shucking process. The goal of this phase is to realize the oyster shucking process by literature review and field survey. Totally, 28 full time shucking workers in Changhua, Yunlin, Chiayi and Tainan participated in the field survey. The investigation focuses on the profiles (gender, anthropometric characteristics of worker’s hand, work experience), shucking method, shucking knife and injuries experienced of the shucking workers. Furthermore, according to the principles of ergonomic hand-tools design, three preliminary knives were proposed and used in the field test; 2) The redesign and evaluation of the preliminary knife proposals. Three more shucking knives based on the result of first phase and ergonomic hand-tools design principles were proposed. Besides, the preliminary knife proposals, the redesign knife proposals and the knives from field investigation were evaluated in lab and the working field. The lab test consisted of two parts: knife exertion and surface electromyography measurement. The goal of knife exertion is to compare the differences of exertion between different knives. On the other hand, the aim of surface electromyograpy measurement is to realize the differences in muscular exertion of operators between different knives. The field tests were conducted in Changhua, Yunlin, Chiayi and Tainan. Totally, 15 shucking workers were tested with the knives performed well in the lab, and the purpose is to know the advantages in real work conditions. 3) In the last phase, this study would analyze the results of former phases and give an exploration on the issues concerning the improvement of oyster shocking knifes applied to the practical circumstance. The field survey reveals that the age of shucking workers are relatively older (mean = 51.8 yr.) and shucking workers are almost all females (female: 27, male: 1); as to the method of oyster shucking, two existing shucking methods were observed from field survey and can be separated by area (Changhua, Yunlin: method 1, Chiayi, Tainan: method 2); 5 different shucking knives were collected, the dimensions and appearences are different from each one.However, the knives used with the same shucking method are with similar dimensions; the mainly injuries of subjects are cumulative trauma disorders caused by operating knives uncomfortably, and immediate trauma disorders from not exerting well with knives and the cutting injuries from the oyster shell. The results of lab experiment indicates that a knife with an angled handle, a protrusion between index finger and thumb, and a large range of curved surface can not only increase the force, but also reduce the muscular exertion of operator in the same exertion level. By observing the use of redesign knives, the redesign knives can maintain the work position of operator in a range of neutral position, meanwhile, the subjective opinion shows that using redesign knives save much effort than the originals.