In order to load or unload a trailer, the warehouse needs a bridge to drive a forklift, pallet jack, or other material handling equipment over the gap. This is where a dock leveler (aka pit leveler) or edge-of-docks comes into play.
Dock LevelersDock Levelers are sometimes called pit levelers because they are mounted within a pit on the dock surface to be level with the driving area. Buyers can choose between mechanical and powered dock levelers. Here are the advantages and disadvantages of each:
Mechanical levelers utilize a spring-loaded design where the operator pulls a chain to release the lock. Once unlocked, the leveler pivots and opens the “lip” of the leveler. The leveler can now be positioned inside the trailer and onto the floor with the trailer in place. In other words, you don’t need to have someone lift the leveler up, back the trailer into position and lower the leveler in place.
Once the loading/unloading process is complete, the process is reversed. The leveler is lifted up, the lip pivots back down, and the leveler is lowered into the locked position. As you can tell, this process takes some time and is slightly hard on the operator. S/he has to be heavy enough to lower the leveler by walking over the surface.
Benefits: minimal acquisition cost and limited maintenance
Cons: time-consuming compared to powered dock levelers and not ideal for high volume applications.
Air-Powered and Hydraulic Dock Levelers
With air-powered or hydraulic dock levelers, all raise/lower functions are accomplished with the push of a button rather than the more labor and time-intensive mechanical option. Further, powered dock levelers can be easily used in conjunction with dock lights and truck locks for a complete safety package/system.
Choosing an air-powered over hydraulic dock leveler comes down to customer preference. For either, the job function and benefits are the same.
Benefits: ease of use, efficiencies for high volume applications
Cons: acquisition price, additional maintenance items (more parts, more opportunities for part failure)
Edge-of-DocksEdge-of-Docks are designed to be mounted to the dock face (rather than the floor/pit of the dock surface) for easy installation. If you have a dock or building that does not have an existing pit or pit leveler, there are significant costs associated with demo-ing the surface and framing for a pit. But an edge-of-dock can simply be anchored to the dock face and welded to the steel angle of the dock.
There are mechanical and hydraulic Edge-of-Docks. Mechanical Edge-of-Docks use a lever to raise and lower the deck into the trailer and are easier use than a mechanical leveler. The mechanical option costs less than the hydraulic, but has a more limited range of operation. Hydraulic Edge-of-Docks operate in the same way as the mechanical version, but the deck is raised and lowered into the trailer by hydraulics at the push of a button.
When to Use a Dock Leveler Vs. Edge-of-Dock
Dock levelers have a greater range of motion than an Edge-of-Dock. Dock heights can range anywhere from 38-55 inches (measured from the ground to the top surface of the dock). Further, there is no standard trailer height; trailers backing up to the dock can range from 40-50+ inches.
A dock leveler has a standard operating range of 12” above and 12” below the dock while an Edge-of-Dock has an operating range of 5” above and 5” below the dock. With the differing dock and trailer heights, a standard Edge-of-Dock may not work.
Further, due to the geometry of the designs, Edge-of-Docks are harsher on the forklift equipment than a dock leveler. The transition from dock to trailer and back is far smoother on a dock leveler than an Edge-of-Dock.
It's important to work with an experienced professional who will ask the right questions and help you make an informed decision. Acquisition price is only one consideration. How the unit will be used, how often and with what equipment are all important factors. Upfront savings can easily be eaten away by labor costs.
East Bay - Livermore (510) 675-0500
Fresno (559) 834-9500
Sacramento (916) 376-0500
Salinas (831) 757-1091