2021-06-03 Dock Levelers: A Crucial Piece of Equipment at the Loading Dock

What is a dock leveler?

A dock leveler is a crucial and most common piece of equipment at a loading dock which is either mounted to the face of the loading dock (edge of dock levelers) or in a pit recessed anchored at the loading dock. Logistics and transportation businesses or even businesses that consist of shipping and receiving on a larger scale are a common place for a dock leveler but not limited to these types of businesses. Even small to medium size businesses with trucks can utilize loading docks and loading dock equipment due to its efficiency and time saving benefits.  

A dock leveler is designed to be an effective and safer way to load and unload products. A dock leveler forms a bridge or ramp of sorts between the loading dock and the truck or trailer that has engaged at the loading dock either loading or unloading products at the building's door. It must also compensate for the weight of the load by allowing the deck to move up and down to absorb the impact from the off load and load movement. A dock leveler is height adjustable to compensate for the types of trailers that back up to the loading dock.

A dock can be operated three ways:

• Mechanical (spring loaded)
• Hydraulic 
• Air powered

How does a dock leveler work as a lift?

Well, to answer that we need to learn about how they are operated. 

What does a mechanical dock leveler do?

• Is spring-powered, requiring manual activation.
• A mechanical dock leveler is operated/actuated by a pull chain system.
• This pull chain system works in sync once actuated with the mechanical components underneath the platform to activate the mechanical dock leveler so it can be walked to lay inside of a trailer.

To operate a mechanical dock leveler, the operator must position the dock leveler onto the trailer bed by pulling the chain located at the rear of the platform. This releases the hold down system which then sets the loaded main lift springs (located under the dock leveler platform) free. As the main platform lifts up it actuates the lip assist to extend the lip out from the dock towards the secured trailer (secured by a vehicle restraint/truck restraints/wheel chocks). The operator then must walk onto the dock leveler and use his or her body weight to lower the platform and lip in alignment of the trailer bed.  Opening the doors for loading and off loading of product can now begin.

Mechanical dock levelers have the optional below dock height service as well. In this case they will need to follow one additional step where after the last step another chain will need to be pulled which is located at the front of the main dock leveler platform. Once the pull chain is actuated it will disengage the support legs that will cause the platform and the lip to drop further down to service below dock height trailers.

Mechanical dock leveler systems comprise a series of parts such as lip-latches, springs, hold-downs, and other moving parts. These parts are consistently under pressure from forklifts or other warehouse operator equipment that perform heavy loading and unloading of cargo, which means they may require frequent maintenance service and replacements.  When deciding which leveler to select, it’s important to review the total lifetime cost of ownership as well as initial capital investment.

Learn what a hydraulic dock leveler is:

A hydraulic dock leveler is a push button operated dock leveler. It consist of 3 main component:

• Main hydraulic ram
• Hydraulic lip ram
• Motor or power pack

The push button is programmed to lift the main platform and extend the lip out. The same push button will store the unit back into close position once the task is complete.

The push-button controls raise the leveler and extend the lip. As the buttons are released, the platform then floats down to the trailer floor. A hydraulic dock leveler tends to operate in a range between 12 inches below and 12 inches above the level of the dock. Normal operation doesn’t require pulling a chain. When loading is complete, the operator pushes a button to return the leveler to its stored position. (An automatic return also can be programmed.) Hydraulic dock levelers are ergonomically efficient and easier on workers because there is no bending and chain pulling, resulting in a lowered chance of injury.

The safety features of a hydraulic dock leveler are velocity fuses. These are factory installed on each hydraulic cylinder. This safety mechanism is a fail safe. In case a hydraulic hose is cut, crushed or severed the velocity fuse will act by gradually bringing the dock leveler down allowing the operator to get to a safe distance.

What are the controls on a airbag dock leveler

An airbag dock leveler is a push button operated dock leveler. It consists of 3 main components: 

•  Airbag
• Support plate 
• Electric air pump

The push button is programmed to inflate the airbag with and lift the main platform and extend the lip out. The same push button will release air and use the weight of the dock leveler to store the unit back into close position once the task is complete.

The functions of an airbag dock leveler are very similar to a hydraulic dock leveler when it comes to how they operate. Only difference is that the hydraulic dock leveler uses a hydraulic cylinder to lift the dock leveler up into position and the airbag uses the support of an airbag for lifting.

Dock safety features

Air powered dock leveler systems use safety legs for free fall protection. Safety legs create "stump out" problems for dock levelers. "Stump out" occurs when a trailer bed's height is below dock level and the safety legs hit their stops. This creates a situation in which only the dock leveler lip (not the dock leveler deck, as the safety legs will not allow the deck to travel downward) can travel with the bed of the trailer. During this condition, when a forklift attempts to back out of the truck, a significant impact occurs to the dock leveler structure and to the forklift driver due to the severe angle the dock leveler lip has been put into, due to the deck being blocked from going the required amount below level, by the safety legs. Health and safety issues and dock leveler damage issues result from impacts of this nature

Availability of other loading dock type equipment/bridge gap between trailer and loading dock 

• Edge of dock (EOD) leveler - This piece of loading dock equipment acts just like the pit recessed dock leveler but on a smaller scale and frequency. This type of dock leveler is mounted to the face of the loading dock and does not require a large footprint as a pit recessed dock leveler.  An EOD can be operated mechanically and push button hydraulic. Very similar to a pit recessed dock leveler, a mechanical EOD needs manual actuation. In this case it would be a lever which is inserted into the platform, pulled back to extend the lip and placed into the trailer bed. Hydraulic EOD is a simple push of the button to extend out then lowered into the trailer bed and second push of a button to retract and store into closed position.
• Scissor lift/dock lift - is a free standing piece of loading dock equipment. It can be either placed into a pit or right in front of the loading dock. A scissor lift not only bridges the gap between trucks and loading docks, at some locations a dock lift can be used to safely and efficiently move product between two levels.

Dock preventative maintenance

To have your loading equipment systems work safe and effectively preventative maintenance is key. The goal of a successful preventative maintenance program to improve the performance and safety of the loading dock equipment. A preventative program is designed to improve equipment life and unplanned maintenance/repair service calls.

Maintenance benefits to dock levelers

• With regular preventative maintenance, equipment down is lowered and the number of major repairs and services are reduced.
• Conservation of assets, higher equipment life expectancy and no unexpected replacement of parts and docks.
• Reduced overtime for in house maintenance costs and better use of maintenance workers because of work on schedule basis.

Loading dock leveler systems are a safer solution which allows loading and unloading trailers efficiently. A dock leveller allows impact from the forklift carrying the load in and out of the door of the trailer. A dock leveler is a much safer solution than using a dock board or a dock plate. This reduces the amount of injuries a workplace may encounter if they were to not have dock leveller. 

Please don’t hesitate to reach out to us at Willtec if you have any questions and would like to learn more about what your options are with your loading dock(s). Our management team has years of experience and can pick the right dock lift systems that will meet your overall needs. Browse all the different dock lifts that we sell, service and maintain on our product pages. Communication with our team is the first step in turning the tables on the life expectancy of your dock equipment.