The mechanical engineer provides expertise in evaluating potential product cases including potential failures, warnings and design claims.

Common Issues the Mechanical Engineering Expert Addresses Regarding Consumer Product Cases:

Consumer Product

  • Product performance
  • Product safety
  • Product design
  • Product modifications
  • Product maintenance
  • Product operation
  • Product warnings, instructions and labels


The Mechanical Engineer:

Consumer Products Expert Witness

  • Reviews information related to incident
  • Evaluates performance of product during incident
  • Reviews intended or proper operating procedures
  • Reviews maintenance and repair records
  • Inspects post-incident condition product components
  • Looks for evidence and time of possible failure
  • Determines specification of product
  • Reviews original design of product
  • Reviews information related to procedures at time of incident
  • Verifies compliance with required standards for product

Consumer Products Expert Case Study

Case Synopsis: A worker at a food processing plant was injured while trying to clear a jam in the inlet tube to a chopper machine. At the time of the incident, the worker was monitoring the flow of vegetables into the machine. The machine’s inlet would occasionally clog, requiring the worker to clear the jammed vegetables. The plant’s procedure to clear the clog was to shut down the chopper machine, thereby stopping the blades, and then use a plastic paddle to clear the clog in the inlet.

On the day of the incident, the worker chose not to use the plastic paddle to clear the jam, and did not shut down the machine prior to trying to clear the jam. While reaching into the inlet of the machine, the worker extended their hand into the machine, placing their hand in the path of the rotating blades. The worker sustained amputation of all four fingers and part of their hand and thumb.

The plaintiff alleged the machine was defective because it allowed the worker to be exposed to the sharp, rotating blades. They indicated the machine should have been designed to automatically shut down in the event of a clog in the inlet to prevent a worker from contacting the blades when they were active.

Expert Analysis: Investigation of the incident revealed there had been alterations made to the machine after it left the control of the manufacturer. As originally designed, manufactured and sold, the machine incorporated a close inlet chute/tube that was approximately four and a half feet long. It was also supplied with a plastic paddle with a T-handle, also four and a half feet long. The instruction for clearing an inlet tube jam in the manual indicated the machine should be turned off and the plastic paddle should be used to clear any jammed materials in the inlet tube. The T-handle of the paddle was designed to prevent the paddle from being able to reach the blades of the chopper. The length of the inlet tube was designed to prevent a worker from being able to get their hand into the chopping area and contacting the sharp blades. It also would prevent them from being exposed to the rotating blades if they were to reach down the inlet with the machine running. In other words, as designed, a worker would not be able to get any portion of their body into the chopping area by reaching into the inlet of the machine.

At some time during the life of the machine, the inlet tube was modified with approximately three feet of the tube being removed. This left an approximately one-and-a-half-foot long inlet tube. With the modified inlet tube, the plaintiff was able to reach down and contact the rotating blades of the machine. This would not be possible with the original design of the machine.

Result: The defendant was able to show that the original design of the chopper machine would have prevented the plaintiff’s injuries from occurring. They were also able to show the injuries occurred due to the modification which occurred to the machine after it left their control.

Manufacturer’s motion for summary judgement was granted.


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