Thomas J. Cocchiola, PE, CSP, Mechanical Engineer ::::
Accident: A manufacturer designed, built, and sold a production line that produces decorative precast concrete pavers. The production line includes a conveyor that automatically feeds precast blocks into a hydraulically powered block splitting machine and positions them under a reciprocating splitter blade. In operation, the block splitter cycles repetitively and breaks the precast blocks into pavers, which are then pushed out through a discharge opening onto a downstream conveyor. The design of the production line requires workers to reach through the discharge opening of the block splitter to manually remove the last paver at the end of a production run.
After the production line was placed into service, the owner/operator became concerned about worker safety. The owner/operator recognized workers were able to reach through the block splitter discharge opening and reach the reciprocating blade (i.e., the danger zone). Consequently, a guard was fabricated and installed to reduce the size of the discharge opening. Unfortunately, the added guard did not prevent workers from reaching the danger zone.
An accident occurred when a worker reached through the discharge opening to remove the last paver at the end of a production run. The block splitter was stationary when he reached through the discharge opening but a malfunction or operator error caused the blade to unexpectedly come down and crush his hand.
Analysis: An engineering analysis determined that the block splitter was deficiently designed because it lacked safeguards to prevent access to the danger zone and that the additional discharge opening guard was inadequate. Workers were able to reach the danger zone with or without the additional guard. The analysis concluded that the manufacturer could have, and should have, designed the block splitter to prevent access to the danger zone.
Results: The case was successfully resolved before trial.
Thomas J. Cocchiola, PE, CSP, is a Mechanical Engineering Consultant with DJS Associates and can be reached via email at experts@forensicDJS.com or via phone at 215-659-2010.