The Ergonomic Study of the Handlebar of the Hack Saw

• Main Authors: Kai-Shiuan Huang, 黃愷軒
• Other Authors: Swei-Pi Wu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/97588881253695815809

碩士 === 華梵大學 === 工業管理學系碩士班 === 92 === The hacksaw is a non-powerded hand tool extensively used by the workers, such as metalworking and woodworking in the industry. However, the conventional hacksaw with a straight handle violate the straight-wrist principle, and frequently causes excessive ulnar deviation and radial deviation of the user’s wrist. Therefore, use the hacksaw may cause cumulative trauma disorders（CTDs）and accidents. Though previous researchers had designed the hacksaw with a bent-handle according to ergonomic perspective, designing both anterior (primary) and posterior (supplemental) handles at a time had not previous been investtigated by ergonomists. The purpose of this work is to investigate the effects of the angles combinations of anterior and posterior handles of hacksaw on the performance and comfort of user’s wrist. A total of 12 males subjects were recruited to participate this study. The independent variables were the angle of anterior handle with four levels（45°, 60°, 75°, and 90°）and tilt angle of posterior handle with four levels（0°, lengthen-0°, lengthen-15°, and left-15°）. Criterion variables include the objective measures of sawing performance, the heart rate, the working posture of the left and the right hands, the grip force dropped percentage, and the ratings of perceived exertion. In addition, the subjects ranked their preference after all of the tasks were completed. The results showed that: (1)The angles of anterior handle had significant influence on the objective measures of sawing performance, and the working posture of the right hand. The optimal angle of sawing performance was 75°, and the worst was 45°. The optimal angle of working posture of the right hand were both 75° and 60°, and the worst was 90°. Overall, the optimal combination of the anterior handle was 75°, and the second was 60°. (2) The tilt angles of posterior handle had significant influence on the objective measures of sawing performance, the ratings of perceived exertion, the subjects ranked preference, and the working posture of the left hand. The optimal tilt angle of posterior handle for the sawing performance, the ratings of perceived exertion, and the subjects ranked preference were all directed to 0°, the second was left-15°, and the worst was lengthen-0°. The optimal angle of working posture of the left hand was lengthen-0°, and the worst was 0°. Overall, the optimal combination of the posterior handle was 0°, the second was left-15°. (3)For all criterion variables, there were no interaction effects exist between the anterior handle and the posterior handle. (4)In general, The optimal combination of the anterior handle angle 75° and posterior handle angle 0° was suggested.