| Summary: | 碩士 === 朝陽科技大學 === 設計研究所 === 93 === A hammer tacker is a necessary tool for workers in the field of carpentry, interior decoration, and construction. Under the condition of incorrect shapes of handles and of the handle-holding ways for a long period of time, ulnar deviation and radial deviation of arm and wrist are very easily caused cumulative trauma disorders. In the research, the principle of hand tool design is “We would rather bend the handle rather than the wrist” with four different angles, 5°, 20°, 35°, 50°respectively, and the adequate shape of handles suitable for intensive exertion are also tested. A subjective questionnaire is completed after the experiment in which EMG records the signal changes of the hands of subject throughout the whole process of the experiment that is aimed at two experimental conditions, the vertical and horizontal aspects. We can see from the analysis that in the muscle strength burden measured from different parts at different angles that 5°is greater than 20°, that 5°is greater than 35°, and 35°is greater than 50°, and it has reached an obvious standard in statistics. However, there is no obvious difference between 20°and 35°. From this we know that at four angles, the burden of muscle is the least at 50°. On top of that, analysis of regression on the %MVC variation for angles over 50°has found out that the lowest point of %MVC falls between 52°and 62° whether it is vertical or horizontal striking operations. Moreover, according to the responses from subjective evaluation analyses, we know that at the angle of 50°, people are the most satisfied with the handling of hammer tackers and express the least complaint about sore carpal muscles.
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