The present disclosure generally pertains to loading dock bumpers, and more specifically to an apparatus or method of retrofitting a conventional dock bumper with a replaceable, protective metal faceplate.
A typical loading dock of a building includes an exterior doorway with an elevated platform for loading and unloading vehicles, such as trucks and trailers. In some cases, a loading dock may include a dock leveler to compensate for a height difference that may exist between the loading dock platform and an adjacent bed of a truck or trailer. Dock levelers typically include a deck whose front edge can be raised or lowered to the approximate height of the truck bed. An extension plate or lip may extend outward from the deck's front edge to span the gap between the rear of the truck bed and the front edge of the deck, thereby providing a path that allows personnel and material handling equipment to readily move on and off the truck bed during loading and unloading operations.
Dock bumpers are often installed near the doorway for several reasons. They can protect the face the building from vehicle impact; they can protect the rear end of the truck from damage; they can prevent a dock seal from being over compressed by a vehicle backing into the dock, and/or in cases where the dock includes a dock leveler, they can establish a predetermined minimum distance between the rear of the vehicle and the dock leveler so that the dock leveler has clearance to operate. Bumpers are typically made of a molded polymer such as rubber or a stack of rubber pads stamped out of old tires, conveyor belt material, or the like. The stack of rubber pads can be clamped between two steel plates. The plates hold the pads together and provide a way for installing the bumper to the loading dock. Bumpers are usually installed near the bottom of the doorway, adjacent either side of the dock leveler lip (if a leveler is present) and protrude a few inches out from the face of the dock where they can be abutted by the rear of the vehicle.
Dock bumpers not only have to absorb the impact of trucks backing into the dock, but they must also endure tremendous vertical friction caused by weight being added and removed from the truck bed as the truck is being loaded or unloaded at the dock. Whenever a forklift, for instance, drives onto or off the truck bed, the truck's suspension allows the bed to rise and fall accordingly. The resulting friction between the face of the bumper and the back of the truck can quickly wear out the bumper.
Replacing a worn bumper can be surprisingly difficult and time consuming. Corroded anchor bolts and mounting plates that have been welded in place and may need to be cut off.
To prolong the life of bumpers and thus reduce their frequency of replacement, some bumpers have their impact absorbing material encased within a telescoping steel housing. The exterior steel plates of such a housing not only provide more wear resistance, but the steel plates also reduce the sliding friction between the bumper and the truck, as the coefficient of friction of metal-to-metal is generally much lower than that of rubber-to-metal. Steel encased bumpers, unfortunately, are very heavy, which makes them even more difficult to replace than rubber ones. Often a hoist of some sort is needed to assist in replacing a steel encased bumper. In addition; there is typically metal-to metal contact between the steel face of such bumpers and the housing—inhibiting their range of full movement.
Consequently, a need exists for a dock bumper that is more durable than conventional rubber bumpers yet is easier to service or replace than today's steel encased bumpers.
In some embodiments, conventional dock bumpers of various sizes are protected by a readily replaceable impactable metal plate.
In some embodiments, a retrofit kit for metal plating existing bumpers includes an adjustment feature for fitting bumpers of various sizes.
In some embodiments, the adjustment feature allows an impactable cover plate to be adjustably tightened against the face of a conventional bumper.
In some embodiments, the retrofit kit adapts to bumpers of various vertical lengths.
In some embodiments, the adjustment feature adapts to the bumper's projection or distance that the bumper protrudes away from the face of the wall or surface to which the bumper is mounted.
In some embodiments, separate brackets mounted independently of an existing bumper can be used for installing an add-on cover plate without having to first temporarily remove or otherwise disturb the bumper.
In some embodiments, the brackets are mounted above and below the existing bumper to make the impactable cover plate easy to install.
In some embodiments, the impactable cover plate can be selectively installed or removed without destroying the bumper's functionality.
The bumper at the right of dock leveler 12 is shown in its originally installed condition without any protective impactable plate, and the bumper at the left side of dock leveler 12 is shown after a bumper retrofit kit 22 has been installed. Kit 22 includes a metal impactable plate 24 that is adapted to overlay the front face of pre-existing, conventional bumpers of various sizes. It should be noted that prior to installing plate 24, bumper 18 as originally installed is a fully functional bumper in itself. Nonetheless, plate 24 helps protect the bumper's front face from wear and provides a reasonably lightweight member that can be readily replaced when necessary. To show a comparison of bumpers with and without the retrofit, only the bumper on the left has impactable plate 24 installed; however, normally both bumpers would be retrofitted in a similar manner.
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The actual design of retrofit kit 22 may vary widely; however, its basic concept is embodied in the example shown in
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To fasten a lower end 80 of plate 72, kit 68 includes a second bracket 82 that can be mounted in a suitable manner to dock wall 20. Bracket 82 has a lip 84 that can engage a threaded fastener 86 screwed into a nut 88 welded to plate 72. A side edge 90 of fastener 86 engaging lip 84 limits the distance that lower end 80 of plate 72 can move away from wall 20. Fastener 86 also provides an adjustment feature and way to readily install and remove plate 72. Under impact pressure from vehicle 14, sliding motion between fastener 86 and lower bracket 82 allows plate 72 to move with the compression of bumper 18, as shown in
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Although the invention is described with respect to multiple embodiments, modifications thereto will be apparent to those skilled in the art. The impactable plate, for example, could be made of steel, stainless steel, or a material other than metal that is intended to be relatively rigid/incompressible as compared to the compressible pad/conventional bumper of the embodiments herein. Also, various features of the multiple embodiments are interchangeable. Items 70, 74 and 78 of