A dock leveler forms a very important part of dock equipment. Dock levelers are primarily mechanical devices which connect the back of the vehicle, truck or ship, to the unloading area. Dock levelers may range from a simple wooden board to metal ramps. These are primarily used for loading and unloading operations with respect to material and machinery. Dock levelers compensate for height differences between the vehicle and the ground level, in order to facilitate smooth transit operations and to prevent damage to expensive equipment and machinery.
Earlier versions of levelers used in dock operations were of a fixed length and were cumbersome to handle. However with the advent of technology, modern day dock levelers are easier to handle and can expand and contract to accommodate space. To facilitate the transfer of heavy equipment, dock levelers can be raised and lowered mechanically. Dock levelers need to have large load bearing capabilities.
Dock levelers are rated by their weight capacity and by something called the service range or height differential. The service range rating refers to the ramp aspect of the dock leveler: how low the leveler can safely angle down and how high the leveler can safely angle up.
There are two main styles of dock levelers which are hydraulic and mechanical. Air powered levelers are also available. Mechanical dock levelers are initially activated by a pull chain. The operator stands on the leveler to engage it properly. Hydraulic dock levelers are operated by a push button panel which provides the leveler with automatic operation. Hydraulic dock levelers have the benefit of providing a smoother transition when they are used with trailers that have soft suspensions. Mechanical dock levelers don't really compensate as well for the lowering of the trailer when loading vehicles enter. They are still safe to use, but often times only the lip of the leveler is in contact with floor of the trailer. Hydraulic dock levelers can compensate fully for the changes in height.
When deciding which leveler to use, there are many factors to consider. These include what types of trucks are used in the operation, the frequency of use, the loading capacities, and the dimensions of the trailers. For instance, lower and wider trucks that have higher capacities need to use longer levelers.