Finger tendon travel associated with sequential trigger nail gun use.
Lowe-B; Albers-J; Hudock-S; Krieg-E
IIE Trans Occup Ergon Hum Factors 2013 Apr; 1(2):109-118
Background: Pneumatic nail guns used in wood framing are equipped with one of two triggering mechanisms. Sequential actuation triggers (SATs) have been shown to be a safer alternative to contact actuation triggers (CATs) because they reduce traumatic injury risk. However, the SAT must be depressed for each individual nail fired, as opposed to the CAT which allows the trigger to be held depressed as nails are fired repeatedly by bumping the safety tip against the workpiece. As such, concerns have been raised about risks for cumulative trauma injury, and reduced productivity, due to repetitive finger motion with the SAT. Purpose: This study developed a method to predict cumulative finger flexor tendon travel associated with the SAT nail gun from finger joint kinematics measured in the trigger actuation and productivity standards for wood frame construction tasks. Methods: Finger motions were measured from six users wearing an instrumented electrogoniometer glove in a simulation of two common framing tasks - wall building and flat nailing of material. Flexor tendon travel was calculated from the ensemble average kinematics for an individual nail fired. Results: Finger flexor tendon travel was attributable mostly to PIP and DIP joint motion. Tendon travel per nail fired appeared to be slightly greater for a wall-building task than a flat nailing task. The present study data, in combination with construction industry productivity standards, suggest that a high production workday would be associated with less than 60 m/day cumulative tendon travel per worker (based on 1,700 trigger presses/day). Conclusion and Applications: These results suggest that exposure to finger tendon travel from SAT nail gun use may be below levels that have been previously associated with high musculoskeletal disorder risk.
Tools; Hand-tools; Pneumatic-tools; Pneumatic-equipment; Musculoskeletal-system; Musculoskeletal-system-disorders; Muscle-stress; Muscle-tension; Construction; Construction-industry; Repetitive-work; Injuries; Traumatic-injuries; Risk-factors; Cumulative-trauma; Cumulative-trauma-disorders;
Author Keywords: nail gun; trigger; repetitive motion; finger tendon; Risk-factors
Brian Lowe, Research Industrial Engineer, National Institute for Occupational Safety and Health, Division of Applied Research and Technology, 4676 Columbia Parkway, Mail Stop C-24, Cincinnati, OH 45226
IIE Transactions on Occupational Ergonomics and Human Factors