Dock shock, it was found, is caused by the vibrations that occur when forklifts drive over the bumps and gaps that exist on traditional dock levelers. In response, Rite-Hite engineers developed the Smooth Transition Dok System, which includes hydraulic, air-powered and mechanical loading dock levelers with specially designed rear hinges and lip crowns that create a thoroughly flat surface between the dock floor and the trailer bed.
According to Tim Muhl, Rite-Hite's project engineering manager, these new dock levelers reduce dock shock by 50 percent.
Rite-Hite has also been working with forklift manufacturers to address vibrations and driver well-being through changes in ergonomics and the designs of their seat cushions, tires, suspension systems, steering columns and engines. "As we began to explore the issue, we discovered that forklift manufacturers alone cannot solve the problem," says Mannone.
Trailer drop, he says, is most prevalent among trailers with air-ride suspensions. In some cases, a trailer can drop as much as 6 inches to 10 inches with the sudden shift in weight when a forklift enters.
To combat trailer drop, Rite-Hite recently launched the STR-4000 Dok-Lok vehicle restraint system, which features a unique rotating hook to engage the trailer's rear impact bar in a two-point lock that restricts trailer movement in any direction. In tests, it reduced trailer drop by 300 percent.
"The hard data alone provides clear evidence that a smooth transition dock system greatly reduces dock shock and trailer drop and the problems they create," says Kyle Nelson, Rite-Hite's vice president of new business and product development. "These issues are gaining recognition and it's the employer's responsibility to control the environment where lift trucks operate. Given the importance of employee safety, as well as the adverse effects it can have on productivity and profitability, it's important that decision-makers are aware of these issues, as well as a solution that allows them to design the problem out of the process."