Dock levelers come in mechanical and hydraulic models. The mechanical models require the operator to pull a chain and then walk down on the leveller to engage it, while hydraulic models provide automatic functionality from push buttons usually mounted on the wall next to the dock door. Hydraulic models also offer a smoother transition when entering vehicles with soft suspensions (such as air-ride). Mechanical levelers use a mechanical safety mechanism to prevent the dock from bottoming out if it disengages from the trailer floor, the side-effect of this safety mechanism is that when you enter a trailer with a soft suspension the main portion of the leveler will not always drop with the suspension, leaving only the hinged lip to make up for the height differential. Hydraulic levelers incorporate a hydraulic velocity fuse as a safety mechanism, this still allows for full functionality of the leveler as the trailer height changes.
The advantages in using automatic dock equipment with electronic controls include the ability to incorporate all of the equipment into signaling devices. Signaling devices such as signal lights will let your lift truck operators know that the restraint mechanism and the dock leveler are properly engaged signaling that it is now safe to enter the trailer, while at the same time signaling the truck driver that it is unsafe to pull away from the dock.
