Preventing Dock-Leveler Stump-Out

There is no one-fix solution to ensure safety at the loading dock, but rather it requires implementing solutions for an array of issues that work in tandem to limit safety risks and increase productivity. While it may be cliche, when it comes to safety at the loading dock, you are only as strong as your weakest link.

Trailer separation and forklifts falling from the edge of the loading dock are familiar safety concerns; in fact, the National Institute of Standards and Technology states that 7% of all reported forklift accidents involve a forklift running off the edge of the dock. However there is a less obvious hazard than the previously discussed that if not addressed, can compromise the integrity and safety of your loading dock operations  - loading dock leveler stump-out.

What is Dock Leveler Stump-Out?

The phrase “stump-out” is used to describe a jarring transition between a trailer bed and a loading dock equipped with a dock leveler.

What Causes Stump-Out?

Stump-out is a peculiar safety issue because it’s caused by a safety feature found on mechanical dock levelers. Mechanical dock levelers utilize safety legs to prevent rapid free-fall that can result if the truck were to prematurely separate from the dock while being loaded or unloaded. While this feature is not only necessary but required, its unintended consequences can be costly.

Let’s say that your mechanical dock leveler comes to rest on the trailer bed, just above dock height. The leveler’s mechanical safety legs will hang freely above the frame posts. As the trailer is loaded, the weight of the forklift causes the trailer bed height to fluctuate from above dock height to below. This is where the issues begin.

When the trailer bed moves to below dock height, the mechanical safety legs will hit the fail safe frame post, preventing the leveler from following the trailer bed down. This results in the lip of the dock leveler adopting a steep slope to reach the trailer bed.

Now, every time the forklift impacts this slope, its load, the forklift and the forklift driver are all at risk.

Top Safety and Security Hazards Associated with Stump-Out

1. Personnel - most importantly, the safety of forklift drivers is at risk during stump-out situations. These often violent, jarring transitions can lead to acute and chronic neck and/or back injuries, which can potentially be serious and costly.

2. Load - the uneven transition can disrupt whatever load is being transferred. If the freight is fragile or susceptible to sudden, harsh movements, you are at risk of compromising the security of its contents.

3. Equipment - it may not be immediately noticeable, but prolonged stump-out situations will wear on not only the dock leveler lip but also your forklift where it can damage tires, counterweights and steering linkage.

Preventing Stump-Out with Hydraulic Dock Levelers

It should be noted that there is a solution while still utilizing a mechanical dock leveler. Most mechanical and power-assisted levelers come with pull-chains to retract the safety legs when the leveler is lowered to service below-dock trailers. When the safety legs are retracted, stump-out is prevented.

The problem with this solution is that stump-out can easily recur, particularly if the leveler is rested on a trailer bed slightly below dock height. As the forklift unloads the trailer, the bed height gradually rises. As soon as the bed height reaches dock level, the safety legs snap back into position. When the forklift enters again, the bed drops. The leveler lip returns to the steep slope position and the stump-out problems are back.

While air-powered dock levelers and hydraulic conversion upgrades provide some protection from stump-out, the optimal solution is to install a dock leveler with full-range free-float. Hydraulic dock levelers are the only leveler to offer this feature. Rather than using mechanical safety legs for free-fall protection, hydraulic dock levelers provide velocity fuse free-fall protection.

This feature allows the leveler to go below dock without having to use personnel to manually retract the legs. Steady contact with the trailer bed is now ensured as it moves above and below dock level - an increasingly important factor to consider since trailer bed heights are trending lower along with the popularity of trailers utilizing air-ride suspension.

Stump-out may seem like a minor hazard, but it’s one that has the potential to be detrimental to your loading dock operations. With your safety and productivity at risk, you can’t afford to ignore it. There are many pieces involved in achieving a safe, secure loading dock operation - preventing dock leveler stump-out needs to be considered one of them.

Prevent Stump-Out and Improve Safety and Productivity with Hydraulic Dock Levelers by Contacting Us Today!