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Factors limiting the use of frame deflection monitoring to predict material jams in baling equipment.
Etherton-J; Moore-P; Harris-J; Zeng-S
NOIRS 1997 Abstracts of the National Occupational Injury Research Symposium 1997. Washington, DC: National Institute for Occupational Safety and Health, 1997 Oct; :60
Recent NIOSH fatality investigations have shown that workers risk amputation and crush injury while attempting to clear jammed material from the loading chambers of operating baling equipment. This type of jam occurs when material fills the gap between the edge of the baler's platen (ram) and an interior wall of the loading chamber. Typical hydraulic actuated cardboard balers generate 50- 70,000 pounds force which tends to shear material lodged in the platen-edge internal-wall gap. This study evaluated the feasibility of developing a process monitor to detect and warn workers of impending jams. A proposal was made at NIOSH that signals generated by strain gage transducers, placed at locations on the machine's frame experiencing large deformations preceding jams, could be used to interrupt platen movement; warn of impending jams by triggering alarms; shut-down the machine; or otherwise provide a new safety control. A system safety analysis using FaultrEASE software was conducted to describe the sources of variation in operating conditions that could confound the transducer response of the proposed safety device. Adequate signal conditioning is also needed to adjust for the effects of temperature differentials, vibration, electromagnetic interference, and other factors present in the indoor and outdoor operating environments typical for these machines. Limiting factors that reduce the precision of monitoring with a single transducer in a complex operating environment were evaluated. The study concludes that mechanical blocking of the platen and proper lockout/tagout should remain the primary control of hazardous energy to prevent baling-equipment-related amputation and crushing injury.
Monitoring-systems; Monitors; Materials-handling; Risk-factors; Risk-analysis; Injuries; Workers; Safety-measures; Environmental-factors; Traumatic-injuries; Injury-prevention
Conference/Symposia Proceedings; Abstract
NOIRS 1997 Abstracts of the National Occupational Injury Research Symposium