Thomas J. Cocchiola, PE, CSP
Mechanical Engineering Consultant ::::
Case Synopsis: The operator of an industrial machine was injured after he walked away from the control console to observe a grinding station component. The machine unintentionally and unexpectedly cycled and injured the operator while he was looking through an opening in a point of operation enclosure. The plaintiff’s expert claimed the accident occurred because an electrician disconnected a safety device while repairing the machine several months before the accident.
Expert Analysis: An investigation and analysis demonstrated that the accident occurred due to design and maintenance deficiencies. The machine was equipped with devices which, if properly designed and maintained, would have prevented the accident. The machine cycled unexpectedly and injured the operator because: a deficient two-hand control did not require continuous activation during the hazardous part of a cycle; an improperly positioned presence-sensing device did not detect operators entering a hazardous area; control system monitoring relays did not detect an inoperable safety control mat; and, the employer constructed a point of operation enclosure without a safety interlock recommended by the machine manufacturer.
Result: Case settled.Categories: Case Studies