Abstract:
A dock seal, such as a head seal mountable above a doorway of a loading dock, includes a compressible body with a support panel. The compressible body can conformably seal against the rear edge of a vehicle&#39;s enclosed trailer as the vehicle backs the trailer up against the seal. The support panel provides relatively dense structure for mounting the seal to the wall of a building. Compared to the horizontal distance that the compressible body projects from the wall, the support panel is ultra-thin to avoid consuming compressible space between the wall and the rear of the trailer. In some cases, a flexible panel suspends the compressible body and its support panel from the wall such that the flexible panel allows the dock seal to move relative to the wall.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The subject disclosure generally pertains to loading dock seals and more specifically to a unique support panel for such a seal. 
       BACKGROUND OF RELATED ART 
       [0002]    When an exterior doorway of a building is used as a loading dock for vehicles, such as trucks and tractor/trailers, the perimeter of the doorway often includes a dock seal. Dock seals close off gaps that would otherwise exist between the exterior face of the building and the back end of the trailer. Dock seals allow cargo from the rear of the trailer to be loaded or unloaded while dockworkers and the cargo are protected from the weather. Usually two side seals run vertically along the lateral edges of the doorway, and a top or head seal runs horizontally along the doorway&#39;s upper edge; however, additional seals can also be used. 
         [0003]    A typical dock seal comprises a resiliently compressible foam core supported by a rigid backer, such as a wood plank or a formed metal plate. The foam core and backer are normally encased within a fabric outer cover. Sealing is provided by backing the trailer up against the seal so that the seal compressively conforms to the rear shape of the trailer. The foam core provides the necessary compliance and resilience to repeatedly conform to the shape of various trailers; the outer cover protects the foam core from dirt, water and wear; and the backer provides solid structure for mounting the seal to the wall and for supporting the foam core so that the foam core does not twist and roll within the fabric cover. 
         [0004]    Due to the trailer&#39;s wheel suspension, adding or removing cargo and/or driving a forklift on and off the trailer bed can cause the rear of the trailer to repeatedly rise and lower a few inches. Although the incidental movement can be a problem, most dock seals are sufficiently wear resistant to tolerate such movement. 
         [0005]    A more serious problem, however, can occur after a tractor backs its trailer up against the dock seal, and the trailer is subsequently unhitched from the tractor while the trailer is still up against the seal. The front end of the unhitched trailer might then be set back down on the trailer&#39;s landing gear or temporarily rehitched onto a special tractor (yard jockey or yard mule) designated specifically for shuffling trailers around the loading dock area. Hitching and unhitching the front end of the trailer can cause the entire trailer to tilt about its rear wheels. The resulting seesaw action produces substantial up and down movement at the rear end of the trailer, which can cut and abrade the dock seal. 
         [0006]    Moreover, when the front end of the trailer is raised, which tilts the rear end of the trailer downward, the upper rear edge of the trailer can dig deeply into the dock&#39;s head seal. When the front end of the trailer is subsequently lowered, the trailer&#39;s rear edge can pry the head seal upward. 
         [0007]    In some cases, the trailer&#39;s rear edge digs into the seal so deeply that the edge catches the seal&#39;s backer and pries the head seal off the wall. This particularly tends to happen with relatively thick backers that are made intentionally thick to provide the foam core with ample support. If the backer is too thin, however, or omitted entirely in order to prevent the trailer&#39;s rear edge from catching the backer, the foam core may tend to roll and twist within the outer fabric cover. Thus, it can be difficult to design a backer with a thickness that addresses both problems. 
       SUMMARY 
       [0008]    In some embodiments, a dock seal comprises a compressible body reinforced by an ultra-thin support panel. 
         [0009]    In some embodiments, the thickness of the support panel is less than 2% of the compressible body&#39;s thickness. 
         [0010]    In some embodiments, the thickness of the support panel is 0.5-1.5% of the compressible body&#39;s thickness. 
         [0011]    In some embodiments, the support panel is a substantially flat piece rather than a formed sheet metal pan with flanges. As a flat piece, the support panel&#39;s material thickness is substantially equal to its panel projection, which maximizes the compressible projection of the dock seal. 
         [0012]    In some embodiments, a flexible panel couples a dock seal and its support panel to a wall such that the flexible panel allows the seal and its support panel to move relative to the wall, wherein the movement is in a direction that is generally perpendicular to the seal&#39;s length. 
         [0013]    In some embodiments, a support panel is embedded within a compressible body so that the support panel can be readily bonded in place. 
         [0014]    In some embodiments, a dock seal includes a front compressible body for sealing against a vehicle and a rear compressible body for sealing against a building wall. 
         [0015]    In some embodiments, the compressible body of a dock seal comprises a collapsible frame supporting a pliable cover. 
         [0016]    In some embodiments, the support panel of a compressible body includes a series of holes that facilitates bonding the panel in place. 
         [0017]    In some embodiments, a dock seal includes a front compressible body for sealing against a vehicle, a rear compressible body for sealing against a building wall, and an intermediate compressible body that helps in bonding a support panel and the rear compressible body to the front compressible body. 
         [0018]    In some embodiments, the dock seal includes a compressible body and a support panel, wherein the relative densities and relative projections of the body and the panel are within a specific novel range such that the dock seal is particularly tolerant of deep gouging and prying by a vehicle pressing up against the seal. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  is a perspective view of a vehicle backing to a loading dock that includes a novel dock seal. 
           [0020]      FIG. 2  is a perspective view similar to  FIG. 1  but showing the vehicle backed up against the dock seal. 
           [0021]      FIG. 3  is a cross-sectional end view of a head seal and a lateral seal with a vehicle approaching the seals. 
           [0022]      FIG. 4  is a cross-sectional end view similar to  FIG. 3  but showing the upper rear edge of the vehicle pressing into the dock seal. 
           [0023]      FIG. 5  is a cross-sectional end view similar to  FIG. 4  but showing the upper rear edge of the vehicle prying the head seal upward. 
           [0024]      FIG. 6  is front view of a head seal with portions cut away to reveal the seal&#39;s inner construction. 
           [0025]      FIG. 7  is a cross-sectional end view similar to  FIG. 3  but showing an alternate design. 
           [0026]      FIG. 8  is a cross-sectional end view similar to  FIGS. 3 and 6  but showing another design. 
           [0027]      FIG. 9  is a cross-sectional end view similar to  FIGS. 3 ,  6 , and  7  but showing yet another design. 
           [0028]      FIG. 10  is a perspective view of another dock seal with portions cut away to show its inner construction. 
           [0029]      FIG. 11  is a perspective view similar to  FIG. 10  but showing both ends of the seal. 
           [0030]      FIG. 12  is a cross-sectional side view of the dock seal of  FIGS. 10 and 11  but showing the seal in a compressed state. 
           [0031]      FIG. 13  is a cross-sectional view similar to  FIG. 12  but showing the seal in its expanded state. 
           [0032]      FIG. 14  is a perspective view similar to  FIG. 1  but showing a dock seal with an alternate shape. 
           [0033]      FIG. 15  is a perspective view similar to  FIGS. 1 and 14  but showing an alternate embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]      FIGS. 1 and 3  show a vehicle  10 , such as a trailer of a truck, backing up to a loading dock  12 . Loading dock  12  is basically a doorway  14  or an opening in a wall  16  of a building and may be associated with a dock leveler  18 , bumpers, and other items that facilitate loading and unloading of the vehicle&#39;s cargo. One such item in particular, which is the subject of this disclosure, is a compressible dock seal  20 . Dock seal  20  may comprise a head seal  22  and/or two lateral seals  24 , which are shown in a relaxed position in  FIGS. 1 and 3 . 
         [0035]    When vehicle  10  is backed up against dock seal  20 , as shown in  FIGS. 2 and 4 , head seal  22  and lateral seals  24  can help close the air gap that might otherwise exist between the outer face of wall  16  and an upper edge  26  and lateral edges  28  of the rear of vehicle  10 . Although much of the gap near a lower rear edge  30  of vehicle  10  is usually blocked off by an extendable lip of dock leveler  18 , it is conceivable for dock seal  20  to also include a lower seal  32  for more complete sealing. 
         [0036]    It is not unusual for vehicle  10  to press its rear edges  26  and  28  tightly against dock seal  20 . If these edges subsequently move up and down due to vehicle  10  being loaded and unloaded of cargo, or the vehicle&#39;s trailer tilts due to the front end of the trailer being hitched or unhitched, then the trailers&#39; rear edges  26  and  28  might dig deeply into seal  20 . In some cases, the vehicle&#39;s upper rear edge  26  might pry head seal  22  upward from its position of  FIG. 4  to a pried-up position of  FIG. 5 . This is a common occurrence when using a yard jockey at a loading dock. 
         [0037]    With a yard jockey, a typical operating sequence would be: 1) a yard jockey lifting the front end of the trailer (thus lowering the trailer&#39;s rear edge); 2) the yard jockey forcing the trailer&#39;s upper rear edge deeply into the dock&#39;s head seal ( FIG. 4 ); and 3) the yard jockey subsequently lowering the front end of the trailer down upon the trailer&#39;s landing gear. As the front end of the trailer descends, the trailer&#39;s upper rear edge pries the head seal upward ( FIG. 5 ). 
         [0038]    To prevent damaging seal  20  under such conditions, head seal  22 , lateral seals  24 , and/or lower seal  32  can be of a construction that tolerates extreme compression, translation, rotation and/or distortion. This can be accomplished by supporting dock seal  20  with something other than a conventional backer; which is usually relatively thick and consumes volume that could otherwise be used for resilient compression and distortion. If a conventional backer of standard thickness were used to support the compressible portion of the seal, there is less room available for compression. In some cases, the support member is fastened to wall  16  with structure that allows some relative movement between seal  20  and wall  16 . Although an example will be described with reference to head seal  22 , the same seal design may also apply to lateral seals  24  and perhaps lower seal  32 . 
         [0039]    Referring to  FIGS. 3-6 , head seal  22  comprises a compressible body  36 , encased within a flexible protective cover  38 . The term, “compressible body” refers to any structure than can resiliently return to its normally expanded shape after being compacted by an external force, such as the force exerted by vehicle  10 . Examples of compressible body  36  include, but are not limited to, a foam block or a collapsible mechanism. In a current example, compressible body  36  comprises a front compressible body  40  and a rear compressible body  42 . Alternatively, compressible body  36  may comprise only front compressible body  40  with rear compressible body  42  being omitted. Rear compressible body  42 , however, can improve the sealing between head seal  22  and the face of wall  16 . Rear compressible body  42  might also help in fastening a support panel  44  to front compressible body  40 , wherein support panel  44  provides suitable structure for fastening head seal  20  to wall  16 . 
         [0040]    Although the actual design of head seal  22  may vary, in a current example, support panel  44  is sandwiched between compressible bodies  40  and  42 . Referring to  FIG. 6 , adhesive  46  bonds bodies  40  and  42  together where the two bodies  40  and  42  come in contact with each other through a series of holes  48  in panel  44  and in an area  50  surrounding an outer perimeter  52  of support panel  44 . Adhesive  46  may also provide some bonding directly between support panel  44  and the facing surfaces of compressible bodies  40  and  42 . 
         [0041]    Even though it is conceivable and well within the scope of the disclosure to bond or otherwise attach support panel  44  directly to compressible body  40  and omit compressible body  42 , such a design does not work quite as well as having support panel  44  interposed between two bondable bodies. If compressible body  40  is not firmly attached to support panel  44  (due to body  42  being omitted, due to the support panel being too pliable, and/or due to panel  44  and body  40  being of different materials that are not readily bonded by a common adhesive), compressible body  40  might move relative to panel  44  and roll within cover  38 . With the addition of compressible body  42 , it has been found that bodies  40  and  42 , being of a similar material, can be readily bonded to each other to firmly capture support panel  44 . 
         [0042]    In a current example, compressible bodies  40  and  42  are made of a class L24 open-cell polyurethane foam; however, other foams and compressible or collapsible structures are well within the scope of the disclosure. Cover  38  can be any appropriate material including, but not be limited to, HYPALON, canvas duck, rubber impregnated fabric and coated nylon fabric. Support panel  44  can be made of metal, plastic or some other material that is substantially thinner and denser than front compressible body  36 . 
         [0043]    To mount head seal  22  to wall  16 , any suitable fastener  54  can be used to fasten support panel  44  directly to the face of wall  16  or used to fasten support panel  44  to one or more flexible panels  56 , which in turn are mounted to wall  16  via another fastener  58 . When vehicle  10  pries upward against seal  22 , as shown in  FIG. 5 , flexible panel  56  allows seal  22  to pivot or move relative to wall  16 . Flexible panel  56  can be made of any appropriately flexible material including, but not limited to, ⅛-inch HMW polyethylene. 
         [0044]    To maximize the compressibility of head seal  22 , support panel  44  is much thinner than front compressible body  40 . When in the relaxed state of  FIG. 3 , front compressible body  40  has a forward surface  60  and a rear surface  62  that define a compressible projection  64  therebetween. Support panel  44  has a thickness or panel projection  66  defined by the distance between a forward-most point  68  and a rearward-most point  70  on panel  44 . To provide head seal  22  with extreme compressibility, seal  22  should have a projection ratio of less than 2%, wherein the projection ratio is defined as panel projection  66  divided by compressible projection  64 . Best results are achieved when the projection ratio is between 0.5% and 1.5%. 
         [0045]    Also, head seal  22  may have a density ratio of less than 3%, wherein the density ratio is defined as density of front compressible body  40  divided by the material density of support panel  44 . Even better results are achieved when the density ratio is less than 1%. For an optimum combination of the projection ratio and the density ratio, the density ratio is may be less than the projection ratio. For a current example, compressible projection  64  is about 8 to 23 inches, panel projection  66  is about ⅛ inch, front body  40  has a density of about 1.5 pounds per cubic foot (24 kg/m3), and support panel  44  has a material density of about 480 pounds per cubic foot when made of steel or about 58 pounds per cubic foot when made of HMW polyethylene. 
         [0046]    To facilitate manufacturability, a slightly modified head seal  72  can be made as shown in  FIG. 7 . In this case, seal  72  includes an intermediate compressible body  74  interposed between support panel  44  and front body  40 . Compressible bodies  40 ,  42  and  74  can all be made of the same material or can be made of different materials. Adhesive  46  can bond bodies  40 ,  42  and  74  together. Once assembled, seal  72  functions basically the same as seal  22 . 
         [0047]    In other embodiments, shown in  FIGS. 8 and 9 , a head seal  76  comprises a resiliently compressible foam core  78  with an integral skin  80 . Skin  80  is denser than core  78  so that skin  80  can provide seal  76  with a protective cover as well as serve as a support panel  82  in the form of flanges that lie generally parallel to wall  16 . Support panel  82  can be used for mounting seal  76  to wall  16  via a conventional fastener  84  and a metal bar  86  ( FIG. 8 ) or via a channel  88  that includes slots for receiving support panel  82  ( FIG. 9 ). Bar  86  and channel  88  may extend fully or partially along the length of seal  76 . Dimensions  90  and  92  represent the seal&#39;s compressible projection and panel projection, respectively. Seal  76  has the general shape of a parallelogram to make seal  76  more compliant in response to vertical motion of vehicle  10 . This same shape can be applied to dock seal  20  as well. 
         [0048]      FIGS. 10-13  illustrate a dock seal  94  (e.g., head seal, lateral seal or lower seal) that includes a hollow compressible body  96  connected to a support panel  98 . Dimensions  100  and  102  ( FIG. 13 ) represent the seal&#39;s compressible projection and panel projection, respectively. Compressible body  96  comprises a protective pliable cover  104  that is supported and held taut between two collapsible frame mechanisms  106 . 
         [0049]    In this particular example, each mechanism  106  includes a generally rectangular frame  108  (or some other suitable shape) with a generally U-shaped brace  110 . The actual shapes of frame  108  and brace  110  may vary. Rotatable couplings  112  pivotally connect both legs of brace  110  to intermediate points on frame  108 . A central section  114  of brace  110  can pivotally rotate within one or more anchors  116  that are fixed relative to wall  16 . Frame  108  includes a section  118  that can both slide and pivot within a slot  120  defined by a track member  122 . The pivotal connections at anchors  116  and couplings  112 , and the combination pivotal/sliding connection at slot  120  allow frame  108  and brace  110  to move between the positions shown in  FIGS. 12 and 13 . 
         [0050]    To help hold cover  104  taut, an elastic member  124  held in tension pulls an outer edge  126  of each frame  106  towards each other. Examples of elastic member  124  include, but are not limited to, a latex tube, a neoprene cord, helical spring, elastic strap, and the like. Elastic member  124  can be attached to frame  108  in any suitable manner. A similar elastic member  128  can be used for holding cover  104  to support panel  98 , while a peripheral lip  130  on cover  104  can provide sealing between wall  16  and dock seal  94 . 
         [0051]    In some cases, elastic member  124  can be used for urging the dock seal to its expanded position. In other cases, however, where edge  126  moves in a generally linear motion between its positions of  FIGS. 12 and 13  (i.e., moves in a direction that is substantially perpendicular to wall  16 ), an additional elastic member or tension spring  132  may be needed to urge dock seal  94  to its expanded position. 
         [0052]    Even though various head seals and lateral seal have been shown as generally straight elongate members, it is well within the scope of the disclosure to provide similarly constructed dock seals of other shapes and designs. Instead of one long member, for instance, head seals  22  and  76  can be comprised of two or more shorter segments that are mounted end-to-end to create an elongate seal assembly of a desired length. 
         [0053]    In other cases, as shown in  FIG. 14 , a head seal  134  includes lateral segments  136  that extend downward toward two lateral seals  138 . In this example, the dock seal assembly does not include a bottom seal. A pliable cover  140  extending downward from segments  136  and overlapping lateral seals  138  can cover the gap between seals  134  and  138 . Such a design helps prevent upper edge  26  of vehicle  10  from digging in between the upper end of a lateral seal and the lower adjoining surface of a generally straight head seal. 
         [0054]    As an alternative to the embodiment of  FIG. 14 ,  FIG. 15  shows a way of providing additional compressibility at an upper end  142  of a lateral seal  144 . Although seal  144  includes a support panel  146  of standard thickness, panel  146  does not extend to the very top of seal  144 . In this example, a head seal  148  can be of any design including, but not limited to, the designs of  FIGS. 3 ,  7 ,  8  and  9 . 
         [0055]    Although the invention is described with respect to various examples, modifications thereto will be apparent to those of ordinary skill in the art. The scope of the invention, therefore, is to be determined by reference to the following claims: