A dock leveler or transfer bridge for ramps, comprising a bridge plate pivotally journalled at its rear end about a horizontal axis on a ramp. The front end of the bridge plate has a foldable or pivotal extension pivoted downwardly in the rest position and, in the working or effective position, pivoted into the plane of the bridge plate. The extension serves for exclusive support of the bridge plate upon the vehicle which is to be loaded or unloaded. When the dock leveler is not being used, the bridge plate is supported upon a pendulum-like strut or support located at the front end thereof. This pendulum-like support, by means of a lever pivotal with the extension, holds or maintains a pivot position for introducing the bridge plate into a ramp recess. In this pivot position, the strut or support cannot correspond or align with its abutment. The strut has an extension prolongation located above its pivot shaft, with the lever engaging behind the prolongation by means of a pull rod pivotally connected to the lever.

A lip extender for use with a loading dock leveler. The lip extender includes a lower link connected at its lower end to the base plate of the leveler and a toggle arm connected at its upper end beneath the lip. The opposite ends of the toggle arm and lower link are pivotally connected together. Upward movement of the hinge connection between the bridge plate and lip moves them both upwardly to a cocked position in which they are supported by the toggle arm and lower link, which pivot into an over-center position. Downward force exerted on the upper part of the bridge plate causes a cam follower carried by the pivotal connection between the toggle arm and lower link to engage a cam surface mounted beneath the bridge plate. The lip is thereby extended simultaneously upwardly and outwardly over the rear edge of a truck disposed adjacent to the dock. When the lip reaches its fully extended position, the toggle arm moves past the center position and allows the lip to drop onto the truck bed.

A safety leg construction for a dockboard which acts to limit normal slow descent of the ramp, as well as rapid descent of the ramp, after a truck pulls away from the dock. Safety legs are hinged to the undersurface of the forward edge of the ramp and are biased to a forward supporting position and are pivotable to a retracted non-supporting position. The legs are coupled to the lip of the dockboard through a releasible latch mechanism which includes an acceleration responsive element. In normal operation when a truck pulls away from the dock after the loading operation is completed, the ramp descends slowly, and the lip pivots downwardly toward the pendant position and the legs pivot toward the forward supporting position to engage fixed supports and support the ramp against further descent. Under a rapid gravitational descent of the ramp caused by an added load on the ramp when the truck pulls away from the dock, the increased acceleration of the ramp will actuate the acceleration responsive element to release the latch mechanism and enable the legs to return, under the force of the biasing means, to the supporting position independently of the position of the lip, to thereby support the ramp against further descent.

A dock leveler having a ramp positioned for engagement with the floor of a truck and freely swingable through a selected angle, both above and below a horizontal position, to accommodate various floor heights. To prevent the ramp from falling more than a small distance, in the event a load is positioned on the ramp and the truck moves away from the ramp, improved cross traffic legs are positioned for coaction with an abutment secured to the dock. There are at least two legs pivotally supported beneath and near the front edge of the ramp for engagement, one at a time, with said abutment whereby the front edge of the ramp is supported at two different levels. Both legs can be moved by manually operable means into nonsupporting positions so that said ramp can drop below said levels.

An improved maintenance assembly for a dockboard having a ramp and a hinged lip. The maintenance assembly includes a lip locking member which is slidably contained in a bracket attached to the bottom of the ramp. A spring connected to the lip locking member urges the locking member into its stored position. When the lip locking member is extended to engage the bottom of the lip and hold it in an elevated position, the lip locking member engages the lip hinge and pivots slightly to bring a detent into engagement with the bracket and thus lock the lip locking member in its operative position.