Hydraulics At Work

The Importance of Making A List... And Checking It Twice

In a recent accident investigation I was involved in, a man was riding unrestrained on the forks of a forklift. While at height, the forks dropped several inches without warning, causing the man standing on the forks to lose his footing and fall to floor. He was seriously injured. The operator was not operating any controls when the forks lost height.

Despite the contributory negligence of the injured party - he was aware that riding on the forks of a forklift without a man cage is not a safe or acceptable practice - a case was brought against a contractor who had performed maintenance work on the forklift prior to the incident.

According to witness reports, the contractor's service technician had been called in to replace a burst hydraulic hose. As a consequence, the presence of air in the hydraulic system - allegedly the result of the service technician's failure to properly bleed the system after replacing the hose - was advanced as the cause of the sudden dropping of the forks by the expert witness for the injured party.

Was air in the hydraulic system the cause of this accident? Well as they often are, the technical arguments surrounding this question were complex. Beyond the physics involved, the complexity of the issue is compounded by the fact that the mechanism for elevating the forks on a forklift typically uses a single-acting, telescopic cylinder with a chain and pulley arrangement. Amongst other things, this results in relative fork movement double that of cylinder movement.

But the more revealing question and moral to this story is: how could this lawsuit (if not the incident) have been avoided in the first place?

What struck me as I reviewed the facts of this case, was the technician who repaired the forklift prior to the incident left the door open to litigation by his failure to do one simple thing. Had he taken the 10-minutes necessary to do it, the lawsuit would never have got off the ground. It was even spelt out for him, if only he'd looked - or been trained to do so.

I'm talking about following proper procedure, and checking it off.

The aviation and aerial access industries have something significant in common. And that is, if you use a mechanical device to defy gravity, you should leave as little to chance as possible. If a jetliner or aerial work platform comes down in an uncontrolled fashion, people get killed or injured.

In the aviation industry, nothing happens by way of aircraft operation or maintenance without a procedure and a corresponding checklist. This is the foundation of the industries' excellent safety record -- which is the premise on which the public's confidence in air travel is based.

The same can't always be said about the aerial access industry specifically - and the hydraulics industry generally. In fact, the use of procedures and checklists is such a valuable and yet much overlooked aspect of hydraulic equipment maintenance, that I spend a whole chapter outlining its many benefits in Insider Secrets to Hydraulics.

In the situation above, had the technician looked in the forklift's operating manual, he would have found a procedure to be followed before the machine was returned to service - after repairs had been carried out on the hydraulic system.

Among other things, this procedure involved carrying out a functional load test. Had the technician followed this procedure and documented it properly, it would have eliminated the possibility of litigation arising from deficient maintenance practices.

Bottom line: not following documented procedure before returning a hydraulic machine to service after maintenance work has been carried out can be a costly mistake. To discover six other costly mistakes you want to be sure to avoid with your hydraulic equipment, get "Six Costly Mistakes Most Hydraulics Users Make... And How You Can Avoid Them!" available for FREE download here.

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