Abstract:
A retrofit kit includes brackets and a readily replaceable impactable cover plate for protecting a conventional polymeric bumper at a loading dock. In some cases, the retrofit kit includes an adjustment feature that allows the impactable cover plate to fit bumpers of various projections, wherein a bumper&#39;s projection is the distance that the bumper protrudes away from the wall or other surface to which the bumper is attached. The impactable plate can be installed to protect various types of conventional bumpers such as unitary molded bumpers or those that comprise a stack of rubber pads. The impactable plate is designed to be more durable and easier to replace than the original bumper itself. The kit and method can be used for retrofitting bumpers made of rubber, plastic or other polymers.

Description:
FIELD OF THE DISCLOSURE  
       [0001]     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.  
       DESCRIPTION OF RELATED ART  
       [0002]     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&#39;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.  
         [0003]     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.  
         [0004]     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&#39;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.  
         [0005]     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.  
         [0006]     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.  
         [0007]     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&#39;s steel encased bumpers.  
       SUMMARY OF THE DISCLOSURE  
       [0008]     In some embodiments, conventional dock bumpers of various sizes are protected by a readily replaceable impactable metal plate.  
         [0009]     In some embodiments, a retrofit kit for metal plating existing bumpers includes an adjustment feature for fitting bumpers of various sizes.  
         [0010]     In some embodiments, the adjustment feature allows an impactable cover plate to be adjustably tightened against the face of a conventional bumper.  
         [0011]     In some embodiments, the retrofit kit adapts to bumpers of various vertical lengths.  
         [0012]     In some embodiments, the adjustment feature adapts to the bumper&#39;s projection or distance that the bumper protrudes away from the face of the wall or surface to which the bumper is mounted.  
         [0013]     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.  
         [0014]     In some embodiments, the brackets are mounted above and below the existing bumper to make the impactable cover plate easy to install.  
         [0015]     In some embodiments, the impactable cover plate can be selectively installed or removed without destroying the bumper&#39;s functionality. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]      FIG. 1  is a perspective view of a loading dock with two existing bumpers of which one is retrofitted with an impactable plate.  
         [0017]      FIG. 2  is a side view of a retrofitted bumper.  
         [0018]      FIG. 3  is a side view of a retrofitted bumper compressed by a vehicle.  
         [0019]      FIG. 4  is a side view showing an existing bumper being retrofitted.  
         [0020]      FIG. 5  is another side view showing an existing bumper being retrofitted.  
         [0021]      FIG. 6  is side view showing a retrofitted bumper being adjusted.  
         [0022]      FIG. 7  is a side view similar to  FIG. 3  only smaller.  
         [0023]      FIG. 8  is a side view of another embodiment of a retrofitted bumper.  
         [0024]      FIG. 9  is a side view of another embodiment of a retrofitted bumper compressed by a vehicle.  
         [0025]      FIG. 10  is a top view of  FIG. 9 .  
         [0026]      FIG. 11  illustrates a first step of installing a bumper.  
         [0027]      FIGS. 12 and 13  illustrate a second step of converting the bumper installed in  FIG. 11 .  
         [0028]      FIG. 14  illustrates a third step of replacing a worn impactable plate. 
     
    
     DESCRIPTION  
       [0029]      FIG. 1  shows a typical loading dock  10  with a dock leveler  12 . To absorb the impact from a vehicle  14  backing into the dock, to ensure adequate operating clearance between a lip  16  of dock leveler  12  and the back of vehicle  14 , and/or to protect a dock seal (not shown) from being over compressed by the back end of vehicle  14 , one or more conventional dock bumpers  18  are attached either to a dock wall  20 , dock leveler  12 , or some other suitable mounting surface.  
         [0030]     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&#39;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.  
         [0031]     Referring to  FIGS. 2 and 3 , the pre-existing bumper  18  (also referred to herein as a “functional bumper”) may comprise a stack of rubber or other polymer pieces  26  together forming a compressible pad that two fasteners  28  clamp between two angle irons  30 , which in turn are fastened to a mounting plate  32  to form a bumper mounting system. Mounting plate  32  may be attached to dock wall  20  in some appropriate manner. An upper edge of mounting plate  32 , for example, might be welded to a metal reinforced corner  34  of dock wall  20 , and a lower end of plate  32  may be held in place by way of a conventional concrete anchor  36 . In other cases, the pre-existing bumper may be a unitary compressible pad molded of rubber, plastic or some other type of polymer. In this context, “compressible” indicates that the pad will be compressed by the backing vehicle as it transmits the force of that vehicle to the dock wall, and then return to a relaxed shape when the force is removed. While all materials have some degree of compressibility, the compressible pad of the embodiments herein is intended to compress substantially more than the relatively rigid/incompressible metal faceplate that overlays the compressible pad according to an inventive concept herein. Phantom lines  38  and  40  representing a plurality of bumpers of various sizes illustrate how kit  22  is capable of fitting other bumpers of indeterminate size, wherein the size is with reference to the bumper&#39;s projection and/or vertical length. Although the invention will be described with reference to a bumper comprising a stack of rubber pads, kit  22  is readily applied to molded bumpers as well.  
         [0032]     The actual design of retrofit kit  22  may vary widely; however, its basic concept is embodied in the example shown in  FIGS. 2 and 3 .  FIGS. 4-6  show how retrofit kit  12  is installed, and  FIG. 7  shows a retrofitted bumper in use.  
         [0033]     Referring to  FIG. 4 , to apply the retrofit kit, a first bracket  42  with an upwardly protruding lip  44  can be mounted to dock  10  adjacent to bumper  18  but not necessarily touching the bumper. Bracket  42 , for example, could be welded to the top or front face of corner  34 . The bracket&#39;s length or distance it extends from corner  34  may first need to be trimmed to a length that is appropriate for the projection of bumper  18 . Concrete anchors  46  can be used for mounting a second bracket  48  to dock wall  20 . Again, the actual construction of brackets  42  and  48  may vary; however, in this example bracket  48  comprises a threaded fastener  50  extending from an anchor plate  52 .  
         [0034]     Next, referring to  FIG. 5 , impactable plate  24  can be hung from upper bracket  42  with a rod  52  or some other catch member of plate  24  resting upon bracket  42 . A lower end  54  of plate  24  can be held in place by a nut  56  that screws onto fastener  50  of lower bracket  48 . Once installed, rod  52  abutting lip  44  and nut  56  engaging lower end  54  limit the extent to which plate  24  can move forward (i.e., away from wall  20 ).  
         [0035]     Referring to  FIG. 6  (similar to  FIG. 2  but smaller), nut  56  and fastener  50  provides an adjustment feature or a way of adjustably tightening plate  24  snuggly up against a front face  58  of bumper  18 . Arrow  60  represents the step of adjustably tightening plate  24 .  
         [0036]     Referring to  FIG. 7  (similar to  FIG. 3  but smaller), in response to impact pressure  62  from vehicle  14 , plate  24  moves back relative to brackets  42  and  48 , as bumper  18  is compressed. As plate  24  moves back, rod  52  slides along upper bracket  42 , creating a gap  64 , and lower end  54  of plate  24  slides along the length of fastener  50 , creating a gap  66 . When the forward movement of vehicle  14  removes pressure  62 , the resilience of bumper  18  pushes plate  24  back to its position of  FIGS. 2 and 6 .  
         [0037]      FIGS. 8, 9  and  10  show another embodiment of a retrofit kit  68 .  FIGS. 8 and 9  correspond to  FIGS. 2 and 3  respectively, and  FIG. 10  is a top view of  FIG. 9 . Instead of lip  44  of bracket  42 , in this example, an upper bracket  70  comprises a key welded atop corner  34 . Instead of rod  52  of plate  24 , an impactable plate  72  includes a two-piece rod assembly  74  or some other type of catch member attached to the underside of plate  72 . Referring to  FIG. 10 , rod assembly  74  defines a notch  76  that fits a guide key  78  attached to corner  34 . Key  78  captured within the two-piece rod assembly  74  prevents plate  72  from sliding sideways off of bumper  18 , yet the sliding fit between key  78  and notch  76  permits relative sliding motion between plate  72  and bracket  70  in a direction perpendicular to dock wall  20  so that plate  72  can move toward wall  20  when forced to do so under impact pressure from vehicle  14 . The position of bracket  70  on corner  34  relative to the position of rod assembly  74  on plate  72  determines how tightly the upper end of plate  72  is held against the front face of bumper  18  when not under pressure from vehicle  14 .  
         [0038]     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  FIG. 9 .  
         [0039]     Arrow  92  of  FIG. 11  represents the first step of installing bumper  18  to a loading dock; arrows  94   a,    94   b,    94   c  and  94   d  represent the second step of converting bumper  18  so that the bumper can be protected by a readily replaceable impactable plate  24 ; and arrows  96   a  and  96   b  of  FIG. 14  illustrate the third step of replacing impactable plate  24  with another plate  24 . The first step (arrow  92 ) is generally the most time consuming, as it may involve drilling in concrete, welding and other heavy operations. Next, the second step of converting the bumper would be less time consuming than the first. Once the bumper is converted, the third step can be performed in less time than the previous two steps.  
         [0040]     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  FIG. 8 , for instance, can be readily incorporated in the embodiment of  FIGS. 2-7 . Therefore, the scope of the invention is to be determined by reference to the following claims.