Ergonomic Hand tool Interventions for the Furniture Manufacturing Industry

Abstract

This project focused on the development of ergonomic interventions to reduce the incidence of musculoskeletal problems in the furniture manufacturing industry. The results of an industry-based survey provided a list of the high priority jobs to be addressed with ergonomic interventions. This paper focuses on the development and evaluation of two of these interventions: an upholstery hand tool and an ergonomic interface for a random orbital sander. Laboratory testing was performed to examine the ergonomic issues with use of each intervention. A reduction in risk factors was found with use of the interventions. The upholstery hand tool reduced grip force from 36 to 18 N, improved hand posture by changing from a pinch grip to a power grip, and reduced the repetition rate from 40 to 24 repetitions per minute. EMG analysis of intrinsic and extrinsic muscles showed a reduction in overall muscle activity and a shift from the intrinsic muscles to the extrinsic finger flexor muscles. The ergonomic interface for the random orbital sander was designed to reduce exposure to vibration and eliminate the need for sustained, static grip force. A subjective survey of users revealed both a short and long term improvement in user comfort and fatigue, while a pre-post study design revealed no significant change in grip strength.