Case Synopsis: A truck driver was injured while making a routine delivery to a supermarket that had a dock lift for unloading freight. The dock lift had a hydraulically powered hoist that raised and lowered its platform between ground level and the truck bed elevation. Delivery truck drivers were able to unload items directly onto the elevated platform before lowering it to the ground. A movable control pendant enabled users to operate the dock lift while standing on the platform. On the day of the accident, the driver backed his truck up and elevated the dock lift before using a jack to unload groceries. He was injured seconds later when the dock lift platform unexpectedly tilted to one side and caused the pallet jack to slide toward him.
Expert Analysis: The platform tilted at the time of the accident because the hoist overextended and caused a hydraulic cylinder to disengage, which left one side unsupported. The dock lift was a relatively old piece of equipment that had been repaired and modified over the years. A limit switch that de-energized the hoist when the platform reached its maximum elevation was replaced, and a stop block intended to restrict upward movement was modified. An evaluation demonstrated that the modified switch and stop did not prevent the hoist from causing the platform to tilt. The evaluation concluded that the dock lift was unsafe to operate due to a lack of routine inspections and maintenance in accordance with applicable safety requirements.
Result: Case resolved in a favorable manner.
For additional information, please contact Tom Cocchiola, Mechanical Engineer with DJS Associates, at experts@forensicDJS.com.