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Critical Review of Studies to Support Safe-Distance Formulas for Power Press Actuation Mechanisms.

Jensen-RC; Pizatella-TJ
Trends in Ergonomics/Human Factors III 1986:953-962
Studies to determine the "safe" distance between the actuator mechanism of a power press and the point on the press at which an injury may occur due to "afterreach movement" were reviewed. The safe distance was considered to depend on the "afterreach speed" (AS) of movement of the hand of a press operator, which was defined by the distance (DA) from the actuator to the danger point divided by the time required for hand movement over that distance. The highest value for AS found for individual subjects was selected as the outcome measure most useful for setting a regulatory standard. To estimate AS, eleven studies in the literature were examined and screened. Three of the studies were selected because the test subjects were machine operators, results of individual fastest afterreach movements were provided, and the test apparatus realistically simulated a press operation. Both the actuator button location and the distance from the danger point were found to affect AS. However, data for the actuator at waist level and shoulder level vertical positions were available for 60 workers but for only one distance. For the waist level horizontal position, data were available for different distances but for only seven workers. The authors conclude that the use of a single hand speed constant appears to oversimplify the situation, and that studies are needed in waist level vertical and shoulder level vertical positions with a range of values of DA, and at the waist level horizontal position for a larger number of workers.
Humans; Industrial-safety; Machine-operators; Safety-engineering; Safety-research; Industrial-design; Equipment-operators; Physiological-measurements;
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Trends in Ergonomics/Human Factors III
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division