Title: Effects of position of the handles and feed force on discomfort score and grip strength during hand drilling
Authors: Jagvir Singh; Abid Ali Khan
Addresses: Department of Mechanical Engineering, Aligarh Muslim University, Aligarh-202002, UP, India. ' Ergonomics Research Division, Department of Mechanical Engineering, Aligarh Muslim University, Aligarh-202002, UP, India
Abstract: This study was to investigate the effect of the position of the main handle and of feed-force on the perceived discomfort-score and on the change in maximum voluntary contraction (MVC) grip strength in a drilling task using a pistol grip hand drill machine. Three positions of the main handle and three feed forces (40, 60 and 80 N) were chosen to perform the study for a given experimental task (i.e., hand drilling). Multivariate analysis of variance (MANOVA) showed that the position of the handle significantly affected discomfort-score (p < 0.001) and MVC grip (p < 0.001), while the effect of feed force was significant only on the discomfort score. With increase in feed force, the vibration levels at the machine were reduced, indicating more vibrations were absorbed at higher feed force by the hand/arm system. The most stressful points were shoulder (84.7% cases), elbow (18% cases), forearm (14.5% cases) and wrist (11.1% cases).
Keywords: hand drilling; drill machines; perceived discomfort score; MVC grip strength; work related musculoskeletal disorders; vibration levels; handle position; feed force; pistol grip; hand drills; multivariate ANOVA; analysis of variance; MANOVA; stress points; human factors; ergonomics.
International Journal of Human Factors and Ergonomics, 2012 Vol.1 No.2, pp.148 - 166
Published online: 06 Aug 2014 *Full-text access for editors Access for subscribers Purchase this article Comment on this article