Effect of operating angles on strength exertion of wrench.

• Main Authors: WU, CHUNG-PEI, 吳仲培
• Other Authors: CAI, DENG-CHUANG
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/42r5am

碩士 === 國立雲林科技大學 === 工業設計系 === 105 === People strengthen the manipulative ability of their hands by way of hand tools so that they can perform many tasks that cannot be operated with their bare hands. The hand tools play an inseparable role in people’s daily life. Taiwan was once known as the kingdom of hand tools with its export ranking the top in the world. Among which, the export amount of the hand tools in wrench category is the most, while the wrench enjoys the widest range of application as well. Furthermore, the horizontal working surface is the most frequently used by people. However, few studies focus on the hand strength exertion concerning the wrenches. A total of 40 healthy adults (20 males and 20 females) aged 22~36 year (SD = 3.07year) with a mean age of 25 year (SD=3.07) were recruited as subjects for hand dimension measurements and strength exertion study. Seven operating angles in two directions of hand strength of the subjects were measured. The two directions were clockwise and counterclockwise. The seven angles were: 0º(pronation at horizontal position), 15º, 30º, 45º pronated and 15º, 30º, 45º supinated. An electronic torque device was used to measure the maximum static strength of hand exertion of the subjects in sitting position. The study results showed that: (1) The average strength exertion was 5.77 kg clockwise and 7.37 kg counterclockwise. The clockwise strength exertion was 0.78 times of the counterclockwise strength exertion. (2) The average strength exertion of females are 5.15 kg and males are 7.99 kg .The strength exertion of females is 0.64 times of that of the males. (3) Males have significantly larger force at two directions and seven angles than the females. Under the condition of being able to apply larger directions and angles, the advantages of males are more distinct. (4) The largest force within every angles is when the wrist rotates clockwise for 15 degrees, where the 0 degree is when palm is downward. The force is getting smaller no matter rotates clockwise or counterclockwise from 15 degrees. The larger the angle is, the smaller the force is.