Investigation of the after-reach hazard in two-hand controlled power press operations.
Pizatella-TJ; Etherton-JR; Jensen-RC; Oppold-JA
Scand J Work, Environ & Health 1983 Apr; 9(2):194-200
The hand injury hazard to power press operators when reaching into the press die area after the downward motion of the press ram started (called after reach) was studied. One safeguard designed to prevent the after reach hazard was to incorporate a two hand actuator control that required pressure from both hands to maintain the motion of the press ram. In this study, a model power press was used to simulate the operation of a power press. The subjects performed simulated work cycles, including a random after reach condition in which subjects were to reach from the actuator controls into the press die area to reposition a work blank. The work blank was dislodged at random intervals by an air valve controlled by an observer who could not be seen by the subject. The after reach time was then measured, and average hand speed calculated. The experiments were performed with the actuator controls in two different positions, an upper and a lower location. The overall mean hand speed was 13.2 meters/second for the upper control position and 0.94 meters/second for the lower position. The authors conclude that the location of the actuator controls has a significant effect on average hand reach speed. More research is needed to define and characterize the additional factors involved in after reach conditions.
NIOSH-Author; Industrial-hazards; Machine-operation; Hand-injuries; Machine-operators; Simulation-methods; Safety-engineering;
Author Keywords: actuator location; after-reach time; hand-reach speed; point of operation; simulated press; two-hand actuator
Scandinavian Journal of Work, Environment and Health