Locking dock with adjustable bumpers

An adjustable bumper system for use at a loading dock which has a dock leveler having a deck pivotally mounted to a portion of the dock. The dock leveler has a lip pivotally attached to one end of said deck. The bumper system has a pair of bumpers each mounted to the end of the deck. The bumpers move with the deck to engage the rear of a vehicle that has backed into position for dock operations. Alternatively, the dock bumpers are mounted to a support member and are positionable between two different vertical positions. The dock bumpers project outward from the dock beyond the pendent lip and are adjustable to engage the rear of vehicles having different heights.

DESCRIPTION OF THE FIRST PREFERRED EMBODIMENT Referring now to FIG. 1 , the loading dock is shown with a driveway approach 1 , a dock face 2 , a wall 3 (partially cut away), and a dock floor 4 with a recessed pit 5 . The pit 5 may have a width the same as or be wider than a conventional dock leveler pit to accept a dock leveler 10 and two bumpers 26 . The dock leveler 10 has a conventional hinged deck assembly 11 and hinged lip assembly 12 . The bumper assembly 26 in the case of a standard width dock leveler is mounted adjacent to the lip 12 . The bumpers are mounted to the end of the deck and preferably at a height such that they are flush with the deck so that any inadvertent movement of a fork lift truck toward the edge of the deck will not damage them. The lip does not extend the full width of the deck but rather is cut away at the ends to allow the bumpers to be mounted. The hinge tube for the lip thus does not extend across the full width of the deck. Typically the width of the lip is slightly less than the width of a truck bed and thus defines the area of movement of a fork lift truck into and out of a vehicle during loading operations. Preferably the deck will be made wider than the truck bed to allow room for a standard width lip between the bumpers. Alternatively, the deck may be a standard width, and the lip will thus be cut down on the sides to allow placement of the bumpers. As shown in FIG. 1 , an optional stop bar 30 is attached to each side of the front of the pit 5 and supports the front of the deck when it is in the lowered position. This will be explained relative to FIG. 3 . FIG. 1 also illustrates the use of conventional lip keepers 20 to support the deck 12 in the horizontal cross-traffic position. The operation of the system in accordance with this first preferred embodiment will now be described. FIG. 1 shows the bumper assemblies 26 and the dock leveler 10 stored at floor level. When the deck 10 is raised to extend the lip and then lowered to the bed of a transport vehicle 50 , the bumpers will be adjacent to but beneath the lip to engage the vehicle and prevent rearward movement into the deck. As the suspension of the vehicle 50 moves vertically in response to being loaded or unloaded, the leveler follows this movement and accordingly the bumpers remain in position aligned with the bed of the vehicle. When a low truck is to be loaded or unloaded, as illustrated in FIG. 2 , the leveler 10 with the lip 12 of the dock leveler 10 is extended and resting on the bed of a transport vehicle 50 . The top of the deck of the dock leveler 10 is below that of the loading dock. In this position the dock is still protected from damage from a low trailer, since as illustrated, the rear of the trailer will impact the bumper 26 and not the dock face. While not illustrated it is apparent that the system will still function with the leveler at the lowest position for “end loading” or removing cargo from the end of the vehicle without the lip extended. That is, the lip can be lowered to the state illustrated in FIG. 1 , but the protrusion of the bumpers 26 still protects the truck. FIG. 3 illustrates the loading dock door 55 in a lowered state onto the leveler which is also lowered. This position is to be used primarily for low trucks. The stop bar 30 supports the leveler since the lip 12 is not constrained by the lip keepers. The stop bar also acts as a barrier sealing of the underside of the support beams, thus providing a degree of security and environmental protection. In this embodiment the stop bar 30 is mounted on the pit floor. It could be carried by the leveler 10 as a leg. This invention is not limited to the specific configuration described above. While the dock shown is for standard height vehicles, this design could be equally as effective for a dock built at a lower height. The lowered position of the bumpers would then be at floor level and the raised position would be above floor level. Similarly, a more complex control system could allow the bumpers to be supported at more than two positions, as described with respect to the second preferred embodiment. 
 DESCRIPTION OF THE SECOND PREFERRED EMBODIMENT Referring now to FIGS. 4 and 5 , a second preferred embodiment is illustrated. The loading dock is shown similar to FIG. 1 . Instead of having the bumper mounted directly to the front plate 24 of the leveler frame, the bumper is mounted on a frame 32 for vertical movement. The frame itself extends below the deck as illustrated in FIG. 5 and is carried by the deck. The bumper is therefore free to be positioned independently of the deck position. FIGS. 4 and 5 are side elevation view illustrating the position of the bumper to block a low truck in two different modes of operation. In FIG. 4 an end loading operation is depicted with the lip 12 retracted but with the deck in the horizontal position. The bumpers 26 are raised to block the truck. Since the useable width of the deck 10 is defined by the width of the lip 12 , the fact that the bumpers on the lateral sides of the deck are raised is of no consequence because they are not in the way of the operator during this last, typically manual, stage of loading the truck to the very rear of the cargo deck. In FIG. 5 the lip is still extended to allow fork lift operations. The bumpers 26 have been lowered on the track 32 to still engage the rear of the vehicle but will not impede movement of the fork lift. The bumpers 26 are thus positionable on the track 32 to match the loading condition encountered. In the case of the second preferred embodiment the bumpers can be simply mounted on tracks rails on the dock leveler face and slide to positions at different vertical positions depending on the configuration of the truck. Simple mechanical stops can be employed and the bumpers positioned by hand. Alternatively, motive sources such as electric motors or mechanical arrangements such as ratchets may be employed.