An ergonomic comparison of pneumatic and electrical pistol grip hand tools

Abstract

The purpose of this study was to compare the ergonomic demands associated with air and DC pistol grip hand tool use. Seven channels of EMG data were collected from 15 male and 15 female subjects to estimate the muscular demands on the forearms, biceps, shoulders and neck. An accelerometer was also used to estimate the torque reaction transmitted to the hand. Subjects performed drilling with five pistol grip tools obtained from two tool suppliers. This resulted in two air tools, one non-transducerized electric (DCNT) and two transducerized electric (DCT) tools. Three types of joints were simulated: (1) 2Nm/720∘, (2) 7Nm/720∘ and (3) 7Nm/30∘. Subjects were asked to drill five joints to completion within a 60s period, and to repeat this five times for each condition (25 joints per condition). Results of a three factor repeated measures ANOVA indicated that, in comparison to air tools, pistol grip DC tools do not pose an additional risk of musculoskeletal injury to the upper limbs. In fact, the data suggest that the use of pistol grip DC tools will reduce the demands on the forearms during horizontal drilling. Relevance to industryPowered hand tools can potentially cause upper limb injuries due to the postures, repetitions, and forces associated with their use. However, while DC tools have engineering advantages (loop monitoring of the tool, and increased quality control) the ability to implement ergonomic strategies also appears to reduce the muscle demands associated with tool use.