Investigation of the after-reach hazard in two-hand controlled power press operations.

One hazard inherent to hand-feeding operations at a power press occurs when a worker reaches into the point of operation after initiating the downward stroke of the press ram. One approach for controlling this hazard is to locate a two-hand actuator at a distance sufficiently far from the point of operation to prevent the operator from getting his hand into the die area before the ram completes its descent. In a study of this problem, the activities of a power press were simulated in the laboratory with the use of a model power press and two locations for the actuator controls, an upper and a lower location. The subjects performed simulated work cycles using the laboratory power press. Randomly an after-reach condition was created in which the subjects were to each into the press die area to reposition a dislodged work blank. The after-reach time, ie, the time needed to reach from the actuator controls to the press die area, was measured. The results of this study indicated that there is a difference in hand-reach speed depending upon the location of the actuator controls. It was concluded that, to define hand-reach speed adequately, more research is needed to characterize the effect of other variables.