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Design recommendations for controlling the jam-clearing hazard on recycling industry balers.
Mick-T; Means-K; Etherton-J; Powers-J; McKenzie-EA Jr.
Proceedings of the ASME 2005 International Mechanical Engineering Congress and Exposition (IMECE2005), November 5-11, 2005, Orlando, Florida. New York: American Society Of Mechanical Engineers, IMECE2005-79699, 2005 Nov; :133-137
Between 1986 and 2002, there were 43 fatalities in the US to operators of recycling industry balers. Of these fatalities, 29 involved horizontal balers that were baling paper and cardboard. Balers often become jammed while the baling process is occurring, and the only way to remove the jam is manually. This requires an employee to place a limb of their body into the jamming area and remove the material that is causing the jam. Although the machine is stopped by the jam, this doesn't mean that the machine is safe. If the machine is still energized there exists the possibility that the baling process will continue once the jam is removed. It is when this happens and the employee does not have a chance to remove their limb from the baling area that amputation occurs. While lockout and tagout procedures reduce the risk of hazardous energy being released, they can still be easily bypassed, ignored, or forgotten. Recent efforts to reduce machine related injury and death involve the development a control system for these machines that automatically detect hazardous operating conditions and responds accordingly. The system is being developed at the National Institute for Occupational Safety and Health (NIOSH). This system, JamAlert, automatically terminates the power to the machine whenever a jam is detected. Once the power is shut off, a trapped-key method is used to make sure that the employee can remove the jam safely without the threat of an unexpected energy release, and the employee can also be a safe distance away from the operating zone before power is restored. This system detects a jam by observing the strain that is experienced by the shear bar of the baler and the hydraulic pressure at which the ram is operating. If both of these measurements exceed a value that is associated with jamming, operation of the machine is stopped by eliminating the power. The power cannot be returned until the proper procedures have been followed. Determination of the strain that is experienced by the baler shear bar when a jam is initiated was calculated in this study through finite element modeling and laboratory testing. Design recommendations are presented on how best to tune the JamAlert's operating program for most effectively controlling the jam-clearing hazard.
Occupational-hazards; Injuries; Traumatic-injuries; Engineering-controls; Control-technology; Machine-guarding; Machine-operators; Machine-operation; Equipment-operators; Equipment-design
Disease and Injury: Traumatic Injuries
Proceedings of the ASME 2005 International Mechanical Engineering Congress and Exposition (IMECE2005), November 5-11, 2005, Orlando, Florida