When a dock leveler is in the closed stored position the front hinged lip assembly is in the vertical position.
Once a truck is backed into position tight to the loading dock bumpers the dock attendant operates the dock leveler. The dock leveler deck assembly raises and when at full height the hinged lip assembly extends, the dock leveler with the lip extended is then lowered onto the bed of the truck and the product transfer begins.
With the hinged lip assembly fully extended it is designed to be at an angle just slightly lower than parallel to the deck assembly, this is referred to as lip crown. The most common dock height is 48” however it is common for incoming truck beds to be lower than 48”, 48” or higher than 48”.
Without this slight downward lip crown the tip of the dock leveler lip would project upwards on any truck bed higher than dock height. The upwards projecting lip would cause a bump when the lift truck or pallet truck moves onto the truck bed and act as a barrier when exiting the truck.
Dock levelers are designed to service a wide range of incoming truck bed heights however there are applications that dock height and the truck bed height are consistently level. In an application that the height differential is minimal or level dock lip crown is not as important and the dock leveler can be ordered with reduced lip crown.
Some things to consider relative to ordering a reduced lip crown are: With time and continued use the crown typically reduces on the dock this is due to wear and eventual fatigue of components that create the lip crown. If the application changes such that a greater crown is desirable adding crown to and existing dock leveler will require expensive parts replacement or dock leveler replacement. The recommendation is not order a special reduced lip crown unless there is a very strong reason that it is required. In the vast majority of applications the standard lip crown provided on the dock leveler is suitable.
In summary dock leveler lip crown assures the hinged lip assembly lies flat on any truck bed higher than dock height.
For additional information on any Pentalift product please contact the Pentalift Sales Department.