Abstract:
Example dock levelers at a truck-loading platform include a stationary curved transition plate extending between a rear edge of the leveler&#39;s pivotal deck and a rear edge of a pit at which the leveler is installed. The transition plate has a curved portion that extends underneath the deck&#39;s rear edge. The plate provides a smooth transition for forklifts traveling between the platform and the deck, thus reducing and/or minimizing the jarring of the forklift and its driver. To prevent debris and obstructions from getting trapped within the deck&#39;s rear hinge, the rear edge of the deck rises up and over the transition plate as the deck pivots upward, thereby providing a self-cleaning effect. With the rear edge of an inclined deck being above the transition plate, water runoff from the deck drains onto the transition plate rather than through the hinge gap to a generally inaccessible area underneath the deck.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    This patent generally pertains to dock levelers and, more specifically, to curved transition plates for pivotal dock leveler decks. 
       BACKGROUND 
       [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. Many loading docks have 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. A dock leveler often includes a deck that is hinged along its back edge so that the deck can pivotally adjust the height of its front edge to an elevation that generally matches the height of the rear edge of the truck or trailer bed. The deck usually has an extendible lip at its front edge that is extended to rest upon the trailer bed to form a bridge between the deck and the bed. This allows personnel and material handling equipment, such as a forklift truck, to readily move on and off the trailer during loading and unloading operations. 
         [0003]    The hinge area at the rear edge of the deck, unfortunately, can present a surface interruption or discontinuity. As the wheels of material handling equipment roll over this area, the surface interruption can jar the moving equipment and its driver. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is a side view of an example dock leveler showing a rear portion of the deck in a cross-traffic position. 
           [0005]      FIG. 2  is a side view similar to  FIG. 1 , but showing the rear portion of the deck in a raised position. 
           [0006]      FIG. 3  is a side view similar to  FIG. 1 , but showing the rear portion of the deck in a lowered position. 
           [0007]      FIG. 4  is a side view similar to  FIG. 1 , but showing the deck in the cross-traffic position. 
           [0008]      FIG. 5  is a side view similar to  FIG. 2 , but showing the deck in the raised position and a lip of the deck partially extended. 
           [0009]      FIG. 6  is a side view similar to  FIG. 3 , but showing the deck in the lowered position. 
           [0010]      FIG. 7  is a side view of the dock leveler of  FIGS. 1-6  showing the deck in a slightly raised position with the lip engaging the bed of a vehicle. 
           [0011]      FIG. 8  is a top view of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0012]      FIGS. 1-8  show an example dock leveler  10  for facilitating the loading and unloading of cargo on a trailer bed  12  or some other vehicle or truck bed. Dock leveler  10  includes a pivotally adjustable deck  14  with an extendible lip  16  that together provide a path or ramp over which a forklift and other material handling vehicle can travel between vehicle bed  12  and an elevated platform  18  of a loading dock  20 . A transition plate  22  provides a relatively smooth transition over which the wheels of the material handling vehicles can travel between platform  18  and a rear edge  24  of deck  14 . 
         [0013]    To adjust the height of the deck&#39;s front edge  26  to roughly align with vehicle bed  12  and/or to move dock leveler  10  between a stored position ( FIGS. 1 and 4 ) and various operating positions, a rear hinge  28  allows deck  14  to pivot about a pivotal axis  30 . Deck  14  can pivot between a range of positions including, but not limited to, a raised position ( FIGS. 2 ,  5  and  7 ), a cross-traffic position ( FIGS. 1 and 4 ), and a lowered position ( FIGS. 3 ,  6  and  8 ). The pivotal motion is driven by any suitable means, examples of which include, but are not limited to, a hydraulic cylinder, a pneumatic cylinder, a fluid powered bladder, a motor driven linear actuator, a mechanical spring, a pneumatic spring, a winch, manual force, and/or various combinations thereof. 
         [0014]    When deployed as shown in the example of  FIG. 7 , deck  14  is in a slightly raised position with lip  16  extended and resting upon vehicle bed  12 . Although the illustrated example shows lip  16  being extendible by virtue of a hinge  32  that pivotally connects lip  16  to the deck&#39;s front edge  26 , other example dock levelers include a lip that extends and retracts in translation relative to the deck. Pivoting or translation of various example lips is driven by any suitable means, examples of which include, but are not limited to, a hydraulic cylinder, a pneumatic cylinder, a fluid powered bladder, a motor driven linear actuator, a mechanical spring, a pneumatic spring, a winch, manual force, linkage between deck  14  and lip  16 , and/or various combinations thereof. 
         [0015]    In the illustrated example, dock leveler  10  includes a frame  34  installed within a pit  36 . In some installations, a shim pack  38  is placed underneath frame  34  such that when deck  14  is in the cross-traffic position ( FIGS. 1 and 4 ), a top surface  40  of deck  14  is generally horizontal and/or flush with platform  18 . Referring to  FIGS. 1 and 8 , a hinge pin  42  of rear hinge  28  pivotally couples a plurality of frame lugs  44  of frame  34  to a plurality of deck lugs  46  of deck  14 , thereby rendering deck  14  pivotal about axis  30 . 
         [0016]    To provide a smooth traffic surface over and/or adjacent to lugs  44  and  46 , transition plate  22  fully spans a horizontal distance  48  between a rear wall  50  of pit  36  and the deck&#39;s rear edge  24 . To provide such full coverage, transition plate  22  comprises a planar portion  22   a  and a curved portion  22   b  that span the distance  48 . Planar portion  22   a  is adjacent to an upper edge  52  of rear wall  50 , and curved portion  22   b  extends underneath rear edge  24  of deck  14  such that axis  30  is between rear wall  50  and a lower edge  53  of curved portion  22   b . Planar portion  22   a  is substantially coplanar with platform  18  and surface  40  when deck  14  is in the cross-traffic position. In some examples, a tack weld joint  54  connects planar portion  22   a  to the pit&#39;s upper edge  52  and edge  52  includes a structural angle  56  with an anchor  58  embedded within the concrete of platform  18 . In some examples, transition plate  22  is a unitary piece with portions  22   a  and  22   b  being integral extensions of each other to provide a preferably smooth seamless transition between portions  22   a  and  22   b.    
         [0017]    Having transition plate  22  extend fully and/or continuously from the pit&#39;s edge  52  to beyond the deck&#39;s rear edge  24  not only reduces and/or minimizes joints adjacent the rear edge  24  of the deck  14 , but also allows the deck&#39;s top surface  40  to extend substantially seamlessly from the deck&#39;s front edge  26  to the rear edge  24 . Also, transition plate  22  being mounted in a fixed, stationary location provides additional benefits that can be appreciated when the adjacent deck  14  moves or rises to the raised position of  FIGS. 2 and 5 . 
         [0018]    As deck  14  rises from the position of  FIG. 1  to that of  FIG. 2 , not only does the deck&#39;s front edge  26  rise, but rear edge  24  also rises. As rear edge  24  rises, any debris or obstruction at a gap  60  between plate  22  and deck  14  would tend to be lifted up and away by the upward movement of the deck&#39;s rear edge  24 , rather than being pulled down into gap  60 . Moreover, if melting snow or other moisture is on the top surface  40  as deck  14  rises to the position of  FIGS. 2 and 5 , rear edge  24  extending above transition plate  22  tends to direct the moisture onto the top of transition plate  22  where the moisture can readily be removed (e.g., mopped or swept away). In contrast, if the deck&#39;s rear edge  24  were below the transition plate, dirt-laden water on deck  14  would tend to drain down through gap  60  and accumulate in pit  36  where removal or cleaning can be difficult. 
         [0019]    Yet another benefit provided by the transition plate  22  of the illustrated example pertains to traction between the deck  16  and the wheels of material handling equipment. For greater traction, the deck&#39;s top surface  40  preferably is textured with an embossed pattern  62  commonly known as “diamond plate,” which is a herringbone pattern of raised rhombi  64 . During manufacturing, however, it may be difficult to bend the diamond plate into curved shapes by brake tooling (although it can be done), as the embossed pattern can interfere with the forming operation. So if a curved transition plate were attached directly to deck  14 , forming the curved plate would be easier if the plate is smooth. A smooth transition plate, however, provides less traction, and traction in the area of the transition plate is particularly important if the plate pivots with the deck. Moreover, if curved portion  22   b  were an integral extension of a deck with a diamond plate top surface, the embossed rhombi  64  on the curved surface would make it difficult to maintain an even radial hinge gap (gap  60 ) at the curved surface. With the illustrated example, the deck&#39;s entire top surface  40  is comprised of a unitary piece of diamond plate that provides a seamless span  64  ( FIG. 4 ) from front edge  26  to rear edge  24 . 
         [0020]    During manufacturing and/or installation, transition plate  22  being designed for stationary mounting at a fixed location makes handling plate  22  easier and less awkward than if it were attached to a large pivotal deck, which can be quite cumbersome. In some installation examples, transition plate  22  is attached to structural angle  56  at pit edge  52  and frame  34  after frame  34  is installed within pit  36 . Deck  14  would then be hung or coupled to the installed structure of frame  34 , transition plate  22 , and structural angle  56 , which can make the dock leveler  10  easier to install. 
         [0021]    In the illustrated example, axis  30  of rear hinge  28  is co-axial with the center of curvature for curved portion  22   b . This ensures gap distance  60  between edge  24  and curved portion  22   b  remains substantially constant as deck  14  pivots about axis  30 . In other examples, the axis  30  of the rear hinge  28  may be eccentric relative to a center of curvature of the curved portion  22   b.    
         [0022]    In some examples, transition plate  22  includes notches  66  ( FIG. 8 ) that provide deck lugs  46  with additional clearance for allowing deck  14  to pivot upward and/or to facilitate the assembly of dock leveler  10 . In some examples, notches  66  provide clearance for receiving deck lugs  46 . In other examples, the notches are sized to provide clearance for both frame lugs  44  and deck lugs  46 . The axial clearances illustrated in  FIG. 8  are exaggerated to show more clearly how transition plate  22  and lugs  44  and  46  fit together. 
         [0023]    Some of the aforementioned examples may include one or more features and/or benefits including, but not limited to, the following: 
         [0024]    Some example dock levelers include a curved transition plate slightly spaced apart from a pivotal deck&#39;s top surface, wherein both the transition plate and the top surface are separate unitary pieces, and the deck&#39;s top surface is a diamond plate that runs seamlessly from a front to rear edge of the deck. 
         [0025]    Some example dock levelers include a curved transition plate that extends underneath the rear edge of a pivotal deck. 
         [0026]    Some example dock levelers include a pivotal deck with a front edge and a rear edge that both rise as the deck pivots upward to a raised position. 
         [0027]    Some example dock levelers include a curved transition plate that can be attached after a frame of the dock leveler is installed within a pit. 
         [0028]    Some example dock levelers include a pivotal deck with a rear edge that can move or push debris and/or other obstructions up and away from a hinge gap. 
         [0029]    Some example dock levelers include a pivotal deck with a rear edge that moves up and over the top of a curved transition plate as the deck rises, whereby water runoff from atop the inclined deck tends to drain onto the transition plate rather than down through a hinge gap that leads to a relatively inaccessible area beneath the deck. 
         [0030]    Some example dock levelers include a transition plate that is structured for stationary mounting at a fixed location, which makes handling of the plate easier and less awkward than if the plate were attached directly to a large cumbersome deck. 
         [0031]    Although certain example methods, apparatus and articles of manufacture have been described herein, the scope of the coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.