Ergonomics investigation for orientation of the handles of wood routers.

OBJECTIVES

Improperly designed hand tools not only expose workers to potential health risks but also hamper their productivity. This study tries to improve the ergonomics of wood routing tasks, suggesting better handle orientations for hand-held wood routers.

METHODS

Seven different handle combinations were tested over two routing tasks (beading and dado) with regard to perceived discomfort, electromyography (EMG) of biceps brachii and extensor carpi radialis brevis and hand-arm vibrations (HAV).

RESULTS

Handles with 30° and 60° inclinations were found more comfortable than previous 90° handle inclinations for routing tasks. Perceived discomfort in the dado task was found to be significantly higher than in the beading task (p < 0.001); EMG activity also supported this observation. However, EMG data showed no significant difference for the different handles used in the study. No worthwhile reduction was obtained in HAV levels for the modified wooden handles compared to initial plastic handles. Relevance to industry. The ergonomic intervention in wood routers described in this article will contribute to the existing knowledge of ergonomics of handle design and will aid the designers/engineers to design such tool handles that may reduce the risk of work-related musculoskeletal disorders/hand-arm vibration syndrome in workers using wood routers.