Abstract:
A compressible seal for a loading dock includes a pliable heat shield that helps protect the seal from concentrated heat generated by a truck&#39;s taillight being pressed against the seal. The seal includes a compressible foam core protected by a tough outer covering. The heat shield is preferably placed against the foam core, just underneath the cover. The shield reflects heat away from the foam and helps disperse the heat over a broader area to reduce the peak temperature of any hot spots.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The subject invention generally pertains to a loading dock and more specifically to a dock seal disposed around a doorway of the dock. 
   2. Description of Related Art 
   When an exterior doorway of a building is used as a loading dock for vehicles, especially trucks, the perimeter of the doorway typically includes a seal known as a dock pad. The dock pad seals off gaps that would otherwise exist between the exterior face of the building and the back end of the truck. This allows cargo from the rear of the truck to be loaded or unloaded while dockworkers and the cargo are protected from the weather. Usually a side dock pad runs vertically along each lateral edge of the doorway, and a top or head pad runs horizontally along the doorway&#39;s upper edge. A typical pad comprises a resiliently compressible foam core protected by a fabric outer covering. Sealing is often provided by backing the truck up against the pad, so that the pad compressively conforms to the shape of the rear of the truck. 
   When a truck backs into a loading dock, in many cases, taillights on the rear of the truck press against the dock pad. This often occurs with taillights that are located along the upper rear edge of the truck, whereby the lights push against the head pad that is mounted over the doorway. Normally, this does not create a problem. However, if the driver of the truck inadvertently leaves the lights on for an extended period (e.g., while the truck is being loaded or unloaded), the dock pad absorbs much of the heat generated by the taillights. The pad&#39;s core being made of foam, which is inherently a poor conductor of heat, tends to keep the heat concentrated to a relatively small area of the pad near the light. Thus, the temperature of that area can rise significantly. Excessively high temperatures can degrade the materials of the pad, or in some extreme cases, may even cause portions of the pad to burn or melt. 
   Perhaps one solution would be to make a dock pad of materials that could tolerate higher temperatures. However, such an approach would likely compromise other desirable qualities of the pad, such as abrasion resistance, puncture resistance, weather resistance, compressibility, resilience, lightweight, appearance, etc., as the materials currently being used are often chosen for the purpose of optimizing these qualities. 
   SUMMARY OF THE INVENTION 
   In order to provide a dock seal that can tolerate heat generated by a vehicle&#39;s taillight, a dock pad comprising a compressible foam core with a pliable outer cover includes a heat shield that helps protect the foam core and its outer cover from excessive heat. 
   In some embodiments, a heat shield is interposed between a dock pad&#39;s foam core and its cover to retain at least some of advantages of the cover. 
   In some embodiments, a dock pad is provided with a heat shield that has appreciable thermal conductivity to help disperse heat. 
   In some embodiments, a dock pad is provided with a heat shield that has appreciable reflectivity to reflect some heat away from a foam core of the dock pad. 
   In some embodiments, a dock pad is provided with a heat shield that can withstand a higher temperature than a foam core of the dock pad, whereby the heat shield helps protect the foam core from heat. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a dock pad that includes a heat shield. 
       FIG. 2  is a cross-sectional view taken along line  2 — 2  of  FIG. 1 . 
       FIG. 3  is a cross-sectional view similar to that of  FIG. 2 , but of another embodiment. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   To create a weather seal between the rear of a truck  10  (or some other vehicle) and the perimeter a loading dock doorway  12 , a dock pad  14  (or dock pad assembly) is installed, as shown in  FIG. 1 . In this example, dock pad  14  includes a side pad  16  mounted along each lateral edge of doorway  12 , and a top or head pad  18  installed along the doorway&#39;s upper edge. Pads  16  and  18  are resiliently compressible, so as truck  10  backs up against them, the pads compressively and sealingly conform to the contour of the truck&#39;s rear edges. 
   To provide dock pad  14  with durability and resilient compressibility, pad  14  includes a resiliently compressible foam core  20  covered by a tough outer cover  22 , as shown in  FIG. 2 . In this example, core  20  consists of a polyurethane or foamed polyester, such as, for example, an L24 open-cell polyurethane foam provided by Leggett &amp; Platt of Carthage, Mo. It should be appreciated by those skilled in the art; however, that a wide variety of other synthetic or natural foams may also work well. In some embodiments, cover  22  is a 3022_MFRLPC_DC7 material provided by the Seaman Corporation of Wooster, Ohio. Other examples of cover materials would include, but are not limited to, HYPALON, canvas duck, rubber-impregnated fabric, and coated nylon fabric. 
   In assembling pad  14 , cover  22  wraps at least partially around core  20 , and the two are attached to a relatively rigid backer  24 , such a formed steel channel or a wood board. Backer  24 , in this example, provides a mounting surface  26  that facilitates the installation of pad  14 . A conventional fastener or anchor can be used to attach backer  24  to a wall  28  of a loading dock  30 . In some embodiments, cover  22  attaches to the side edges of backer  24  by any one of a variety of fasteners including, but not limited to, screws, VEECRO, rivets, hooks, and adhesive. Core  20  can be frictionally held to cover  22 , or the two can be joined in a more positive manner. For example, cover  22  can be connected to core  20  with adhesive, straps, hooks, VELCRO, stitches, screws, etc. 
   To make pad  14  more resistant to heat, such as heat generated by a taillight  32  pressing against certain points  34  on a sealing surface  36  of pad  14 , a heat shield  38  is attached to pad  14 . In some embodiments, heat shield  38  is incorporated within a Commercial Material RTCM01, which consists of two flexible sheets or layers of perforated aluminum foil reinforced with a polyethylene scrim or fabric, as provided by Radiant Technology, of Dallas, Tex. The flexibility of shield  38  is preferably sufficient to allow dock pad  14  to compressively conform to the contour of the truck&#39;s rear edges and then decompress to the pad&#39;s original shape. Heat shield  38  can be attached to pad  14  using adhesive, friction, straps, stitches, and/or various other fasteners. Shield  38  can be attached to the exterior or interior of pad  14 , however; shield  38  is preferably installed between cover  22  and foam core  20  for structural, functional, and aesthetic reasons. 
   Placing shield  38  underneath cover  22 , helps keep cover  22  exposed to the outside, thus taking advantage of the cover&#39;s toughness, weather resistance and pliability. Moreover, shield  38  preferably has a higher reflectivity than core  20  and cover  22 . This can be beneficial in cases where the cover can withstand a higher temperature than the core, wherein “withstand a higher temperature” means a material can be raised to the higher temperature and then substantially recover its original properties after its temperature returns to normal. For example, if the foam of core  20  has an auto ignition point (i.e., temperature at which the material self-ignites without being triggered by a spark or a flame) of 700 degrees Fahrenheit and cover  22  has an auto ignition point of 900 degrees, then heat shield  38  with high reflectivity could reflect heat away from the foam and redirect it into cover  22 , which may be able to handle the heat better. In some embodiments, both cover  22  and core  20  have a lower auto ignition point than heat shield  38  (e.g., when shield  38  is one of the two layers of aluminum foil contained within Commercial Material RTCM01). 
   To reduce peak temperatures of core  20  and/or cover  22  when heated by taillight  32 , heat shield  38  is made of a material that has a higher thermal conductivity than core  20  and/or cover  22 . The maximum temperature at areas of concentrated heat, such as points  34 , is reduced by shield  38  being able to effectively disperse the heat over a broader area. The term, “thermal conductivity” refers to a material&#39;s ability to conduct heat of a given temperature gradient along a given length and through a given cross-sectional area of the material, thus thermal conductivity is a property of the material itself, and is generally independent of the material&#39;s shape. A typical unit of measure for thermal conductivity would be (Btu)/(hr)(ft)(° F.). 
   To provide even greater heat protection, another embodiment, similar to that of  FIG. 2 , provides a dock pad  14 ′ with two heat shields  38 ′, as shown in  FIG. 3 . It is believed that additional heat protection is provided by the additional overall thickness of the two shields and perhaps partially provided by virtue of an additional slight air interface  40  that may exist between the two shields  38 ′. Moreover, for a given total thickness, two individual shields instead of one relatively thick one is more flexible, just as a stack of individual cards is more flexible than a stack of cards whose faces are glued together. 
   A strap  42  inserted through a slit  44  in foam core  20 ′ helps hold the two shields  38 ′ in place. A loop  46  at each end of strap  44  engages holes  48  in shields  38 ′; however, strap  42  could attach to shields  38 ′ in a variety of other ways as well. Also, strap  42  could feed around the back of core  20 ′ to eliminate the need for slit  44 ; however, strap  42  extending through slit  44  helps keep strap  42  and shields  38 ′ from shifting along the length of a pad. 
   Although the invention is described with reference to a preferred embodiment, it should be appreciated by those skilled in the art that various modifications are well within the scope of the invention. For example, although the illustrated dock pads have cross-sections that are generally rectangular, various other shapes are also well within the scope of the invention. Moreover, the shape of the head pad could be different than that of the two side pads. One or more heat shields can be applied to just the head pad, just the side pads, or applied to both the head and side pads. Therefore, the scope of the invention is to be determined by reference to the claims that follow.