Abstract:
A repositionable loading dock pit seal panel comprising: (a) a repositionable pit seal panel including a substantially incompressible height and width sized to substantially span an entire vertical dimension and substantially span an entire widthwise dimension of a loading dock pit to substantially close off a cross-sectional area of the loading dock pit when the repositionable pit seal panel is in a barrier position, where the repositionable pit seal panel is repositionably mounted to at least one of an overhead door, a surface partially defining the loading dock pit, and a surface adjacent to the loading dock pit, where the repositionable pit seal panel is repositionable between the barrier position inhibiting horizontal use of a vertically stored dock leveler and a storage position allowing horizontal use of the vertically stored dock leveler, where the repositionable pit seal panel in the barrier position cooperates with the overhead door to close off a loading dock opening defined by a loading dock doorway and the cross-sectional area of the loading dock pit, and where the width of the repositionable pit seal panel is less than a width of a bottom section of the overhead door.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/242,112, entitled, “REPOSITIONABLE PIT SEAL,” filed Sep. 14, 2009. 
     
    
     RELATED ART 
       [0002]    1. Field of the Invention 
         [0003]    The present invention is directed to a novel art, repositionable pit seals for shipping dock pits originally designed to accommodate horizontally stored dock levelers, but retrofitted to accommodate vertically stored dock levelers. 
         [0004]    2. Brief Discussion of Related Art 
         [0005]    Referring to  FIG. 1 , Vertical Storing Dock Levelers (VSDLs)  10  are commonly hydraulically operated dock levelers that provide a generally horizontal gangway between the floor  12  of a building and the floor of a transport vehicle (i.e., a truck or tractor trailer) in order to load and unload goods between the building and the transport vehicle. As the name indicates, VSDLs  10  are stored vertically, in contrast to the horizontal use position, and allow the recessed floor  14  of the building to which the VSDL is mounted to be accessible for clean-up purposes. 
         [0006]    In circumstances where a building is designed to accommodate VSDLs  10 , a two-tiered or stair-stepped building floor is poured. The first, upper tier floor  12  is the primary floor of the building and is generally level across the vast majority of the building. But the second tier floor or bottom floor  14  is vertically lower than the upper tier floor by approximately 10-12 inches. This second tier floor  14  is substantially level and commonly extends across the entire side of the building where one or more loading docks are located. The opening of each loading dock may be closed off exclusively by an overhead door. 
         [0007]    Consistent with the foregoing reference system, C-channel track for the overhead door (not shown) may extend to the surface of the second tier floor  14 . The overhead door vertically and horizontally spans the entire loading dock opening when in a lowered position. This lowered position corresponds to the bottom of the overhead door abutting the top surface of the second tier floor  14  to substantially prevent air loss gaps and access for vermin entry. In other words, the overhead door extends vertically below the horizontal surface of the first tier floor  12 . 
         [0008]    Referencing  FIG. 2 , in circumstances where a building is designed to accommodate horizontally stored dock levelers  22 , individual rectangular pits  16  are formed into the concrete floor to accommodate each dock leveler. The walls of the pit  16  partially define a cubic rectangular cavity and include a right side wall  18 , a left side wall  20 , a rear wall, and a floor  24 . In some cases, the pit walls  18 ,  20 ,  24  are lined with a metal insert. Nevertheless, horizontally stored dock levelers  22  are repositionable to change the pitch of the gangway or dock floor to accommodate loading heights higher and lower than the building floor. 
         [0009]    Conventional horizontally stored dock levelers  22  include a top surface or deck that is generally level with that of the building floor surrounding the pit  16  when the dock leveler is not in use. As a result of this horizontal storage position, conventional overhead doors contact the gangway of the dock leveler  22  so that both the overhead door and dock leveler block the opening of the dock. In other words, the overhead doors do not close off the portion of the loading dock opening partially occupied by the dock leveler. This also means that the C-channel guides for the overhead doors only extend to the building floor, which is elevated with respect to the pit floor. Thus, any gap between the top of the dock leveler (gangway) and the pit floor cannot be closed off by an overhead door. Because gaps between the dock leveler  22  and pit  16  cannot be sealed by the overhead door, these gaps allow airflow therethrough, as well as access for vermin. Because of these problems, many buildings designed to use horizontally stored dock levelers  22  have been retrofit to accommodate VSDLs  10 . But this retrofitting comes at a considerable price. 
         [0010]    Retrofitting costs to convert a building previously using horizontally stored dock levelers  22  to VSDLs  10  are substantial. First, the vertical storage orientation of the VSDLs  10  requires the overhead door to close off the entire dock opening. In order to accommodate an overhead door that goes beyond the primary building floor and extends into the pit  16 , concrete must be removed on both sides of the pit below the location of the old C-channel overhead door guides. Thereafter, new C-channel is installed that extends into the floor of the expanded pit  16 . In addition, at least one new section must be added to the overhead door to provide the increased vertical length necessary to close off the opening. Alternatively, an entirely new overhead door may be installed. Not only are the direct costs associated with retrofitting expensive, but so too are the indirect costs associated with losing access to a loading dock until the retrofitting is complete. 
       INTRODUCTION TO THE INVENTION 
       [0011]    The instant disclosure provides an alternative to conventional retrofitting of buildings to accommodate VSDLs  10 . In particular the instant disclosure provides a more cost effective alternative by substantially lessening expenses and down time to switch a loading dock from the horizontally stored dock leveler  22  to a VSDL  10 . Of particular importance, the instant disclosure allows building owners to maintain their existing overhead doors, track, and floor. Instead of cutting out portions of the building floor to bring the overhead door to the floor, as is the case in the prior art, the instant disclosure is operative to bring the floor to the door or bring the door to the floor without changing the dimensions of the floor. Specifically, the vertical depth and width at the front of a conventional pit is closed off using a repositionable pit seal. This repositionable pit seal may be mounted to the pit floor or to the overhead door in order to close off the vertical depth and width of the pit when the VSDL  10  is in its vertical storage position. However, when the VSDL  10  is in its horizontal use position, the repositionable pit seal is moved out of the way of the VSDL. The repositionable pit seal may be automatically or manually repositioned by the actuation of the overhead door, the actuation of the VSDL  10 , or an independent device. The repositionable pit seal is operative to reduce drafts through the front opening of the pit and allows buildings having dock leveler pits to be retrofit without expanding the pit or replacing the preexisting overhead door. 
         [0012]    It is a first aspect of the present invention to provide a repositionable loading dock pit seal panel comprising a repositionable pit seal panel including a substantially incompressible height and width sized to substantially span an entire vertical dimension and substantially span an entire widthwise dimension of a loading dock pit to substantially close off a cross-sectional area of the loading dock pit when the repositionable pit seal panel is in a barrier position, where the repositionable pit seal panel is repositionably mounted to at least one of an overhead door, a surface partially defining the loading dock pit, and a surface adjacent to the loading dock pit, where the repositionable pit seal panel is repositionable between the barrier position inhibiting horizontal use of a vertically stored dock leveler and a storage position allowing horizontal use of the vertically stored dock leveler, where the repositionable pit seal panel in the barrier position cooperates with the overhead door to close off a loading dock opening defined by a loading dock doorway and the cross-sectional area of the loading dock pit, and where the width of the repositionable pit seal panel is less than a width of a bottom section of the overhead door. 
         [0013]    In a more detailed embodiment of the first aspect, the repositionable pit seal panel includes a front wall spaced apart and extending substantially in parallel to a rear wall, the front wall is joined to the rear wall by at least one interposing wall. In yet another more detailed embodiment, the at least one interposing wall comprises a plurality of interposing walls, and at least one of the plurality of interposing walls includes a wall extending substantially perpendicularly to both the front wall and the rear wall. In a further detailed embodiment, the at least one interposing wall comprises a plurality of interposing walls, and at least one of the plurality of interposing walls includes a wall angled other than perpendicularly with respect to both the front wall and rear wall. In still a further detailed embodiment, the repositionable pit seal panel includes a front wall spaced apart and extending substantially in parallel to a rear wall, the front wall being joined to the rear wall by at least one interposing wall, and the repositionable loading dock pit seal panel is fabricated from extruded plastic. In a more detailed embodiment, a top of the repositionable loading dock pit seal panel includes a longitudinal projection extending substantially the entire width of the repositionable loading dock pit seal panel, and the longitudinal projection is shaped to be received within a longitudinal cavity formed within the bottom section of the overhead door. In another more detailed embodiment, a top of the repositionable loading dock pit seal panel includes a longitudinal groove extending substantially the entire width of the repositionable loading dock pit seal panel, and the longitudinal groove is shaped to receive a longitudinal projection extending from the bottom section of the overhead door. In yet another more detailed embodiment, the invention further comprises weatherstripping mounted about at least a portion of a perimeter of the repositionable loading dock pit seal panel, wherein the weatherstripping and the repositionable pit seal panel completely span the entire widthwise dimension of a loading dock pit to close off a cross-sectional area of the loading dock pit when the repositionable pit seal panel is in a barrier position. In still another more detailed embodiment, the perimeter includes right, left, and bottom walls of the repositionable loading dock pit seal panel. 
         [0014]    In yet another more detailed embodiment of the first aspect, the invention further comprises a mechanical connection extending between the repositionable pit seal panel and the vertically stored dock leveler, where repositioning of the vertically stored dock leveler between a vertical default position and a horizontal use position is correspondingly operative to reposition the repositionable pit seal panel between the barrier position and the storage position. In still another more detailed embodiment, the mechanical connection includes a cable operatively engaging at least one pulley. In a further detailed embodiment, the mechanical connection includes a linkage bar concurrently mounted to the repositionable pit seal panel and the vertically stored dock leveler. In still a further detailed embodiment, the repositionable pit seal panel is repositionably mounted to the overhead door, the repositionable pit seal panel is pivotally mounted to the overhead door and repositionable between a coplanar orientation in its barrier position and a non-coplanar orientation in its storage position, and the repositionable pit seal panel is removed from the loading dock pit when in its storage position. In a more detailed embodiment, the invention further includes a motor operatively coupled to both the repositionable pit seal panel and the overhead door, the motor operative to reposition the repositionable pit seal panel between its co-planar orientation and non-coplanar orientation with respect to the overhead door. In a more detailed embodiment, the invention further comprises a motor operatively coupled to both the repositionable pit seal panel and at least one surface partially defining the loading dock pit, the motor operative to reposition the repositionable pit seal panel between its barrier position and its storage position. In another more detailed embodiment, the repositionable pit seal panel is repositionably mounted to a surface partially defining the loading dock pit, the repositionable pit seal panel is pivotally mounted to opposed vertical side walls partially defining the loading dock pit, and the repositionable pit seal panel remains within the loading dock pit when in its storage position. In yet another more detailed embodiment, the invention further comprises weather stripping extending from at least one of a left side and a right side demarcating the width of the repositionable pit seal panel. In yet a further more detailed embodiment, a bottom of the repositionable pit seal panel includes a projection adapted to be received within a cavity extending into a floor of the loading dock pit. In yet a still further more detailed embodiment, the invention further comprises a roller mounted to one of the vertically stored dock leveler and the repositionable pit seal panel, wherein the roller is adapted to be selectively contacted by the other of the vertically stored dock leveler or the repositionable pit seal panel to reposition the repositionable pit seal panel toward the barrier position when the vertically stored dock leveler is repositioned toward a vertical default storage position. 
         [0015]    It is a second aspect of the present invention to provide a repositionable loading dock pit seal panel comprising a substantially rigid repositionable pit seal panel occupying a rectangular area and including a top wall, a bottom wall, a left side, a right side, and a front wall extending between the left and right sides and between the top wall and the bottom wall, the front wall spaced apart from a rear wall by an intermediary wall, the substantially rigid repositionable pit seal panel including a widthwise dimension substantially spanning a widthwise dimension of a loading dock pit, the substantially rigid repositionable pit seal panel including a height substantially spanning a depth of a loading dock pit, the top wall including at least one of a keyway and a key extending longitudinally in parallel with the bottom wall and adapted to engage the bottom of an overhead door, the repositionable pit seal panel having mounted thereto a repositioning device to facilitate repositioning of the repositionable pit seal panel between a vertical barrier position and a non-vertical storage position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a perspective view of a vertical stored dock leveler, showing the underneath surface of the dock leveler. 
           [0017]      FIG. 2  is an elevated perspective view of a horizontally stored dock leveler, shown in its fully raised position. 
           [0018]      FIG. 3  is an elevated, isolated perspective view of a convention loading dock pit, with an overhead door in the closed position. 
           [0019]      FIG. 4  is an elevated perspective view of an exemplary repositionable pit seal mounted within a conventional loading dock pit, where the pit seal is shown in its vertical deployed position and where the overhead door is shown in its closed position. 
           [0020]      FIG. 5  a perspective view of a vertical stored dock leveler mounted within a conventional loading dock pit and stored in its vertical storage position. 
           [0021]      FIG. 6  are cross-sectional views of mounting brackets for use with an exemplary embodiment of the disclosure. 
           [0022]      FIG. 7  is a cross-sectional view of an exemplary pit seal panel in accordance with an exemplary embodiment of the disclosure. 
           [0023]      FIG. 8  is an isolated, perspective view of a top corner of a pit seal panel in accordance with an exemplary embodiment of the disclosure. 
           [0024]      FIG. 9  is a cross-sectional view of weather-stripping for use with the exemplary embodiments of the disclosure. 
           [0025]      FIG. 10  is a cross-sectional view of further weather-stripping for use with the exemplary embodiments of the disclosure. 
           [0026]      FIG. 11  is a profile view of an exemplary pit seal in accordance with the disclosure. 
           [0027]      FIG. 12  is a profile view of an exemplary pit seal of  FIG. 11 , shown in initial engagement with a lowered vertically stored dock leveler. 
           [0028]      FIG. 13  is a profile view of an exemplary pit seal of  FIG. 11 , shown in engagement with a lowered vertically stored dock leveler, where the dock leveler is lowered more than shown in  FIG. 12 . 
           [0029]      FIG. 14  is a profile view of an exemplary pit seal of  FIG. 11 , shown in engagement with a lowered vertically stored dock leveler, where the dock leveler is lowered more than shown in  FIG. 13 . 
           [0030]      FIG. 15  is a profile view of an exemplary pit seal of  FIG. 11 , shown in engagement with a lowered vertically stored dock leveler, where the dock leveler is lowered more than shown in  FIG. 14 . 
           [0031]      FIG. 16  is a profile view of the left side of an exemplary pit having an exemplary pit seal installed and mounted to a vertically stored dock leveler. 
           [0032]      FIG. 17  is a frontal view of the exemplary pit seal of  FIG. 16  installed and mounted to a vertically stored dock leveler. 
           [0033]      FIG. 18  is a profile view of the mechanical linkage between the exemplary pit seal of  FIG. 16  and a vertically stored dock leveler. 
           [0034]      FIG. 19  is a profile view of the mechanical linkage of  FIG. 18  when the vertically stored dock leveler is lowered beyond that shown in  FIG. 18 . 
           [0035]      FIG. 20  is a profile view of the mechanical linkage of  FIG. 18  when the vertically stored dock leveler is lowered beyond that shown in  FIG. 19 . 
           [0036]      FIG. 21  is a profile view of the mechanical linkage of  FIG. 18  when the vertically stored dock leveler is lowered beyond that shown in  FIG. 20 . 
           [0037]      FIG. 22  is a profile view of an alternate mechanical linkage between the exemplary pit seal and a vertically stored dock leveler when the dock leveler is positioned in its vertical storage position. 
           [0038]      FIG. 23  is a profile view of an alternate mechanical linkage of  FIG. 22  showing the position of the between the exemplary pit seal of  FIG. 23  and a vertically stored dock leveler when the dock leveler is lowered to its horizontal use position. 
           [0039]      FIG. 24  is a rear view of an exemplary pit seal mounted to a conventional overhead door, where the pit seal is shown in its vertical barrier position and where the overhead door is shown in its closed position. 
           [0040]      FIG. 25  is a cross-sectional view of the exemplary pit seal panel, weather-stripping retainer, and weather-stripping comprising a part of the exemplary pit seal of  FIG. 24 . 
           [0041]      FIG. 26  is a rear view of the exemplary pit seal of  FIG. 24 , where the pit seal is pivoted with respect to the overhead door when the overhead door is in its open position. 
       
    
    
     DETAILED DESCRIPTION 
       [0042]    The exemplary embodiments of the present disclosure are described and illustrated below to encompass repositionable pit doors for dock leveler pits. Of course, it will be apparent to those of ordinary skill in the art that the embodiments discussed below are exemplary in nature and may be reconfigured without departing from the scope and spirit of the present invention. However, for clarity and precision, the exemplary embodiments as discussed below may include optional steps, methods, and features that one of ordinary skill should recognize as not being a requisite to fall within the scope of the present invention. 
         [0043]    Referencing  FIGS. 3 and 4 , an exemplary loading dock  100  includes a pit  102  formed within a floor  112  of a warehouse or other loading/unloading facility that previously accommodated a horizontally stored dock leveler. The pit includes right  104 , left  106 , and rear  108  walls, in addition to a recessed (with respect to the warehouse floor  112 ) horizontal floor  110 . The warehouse floor  112  adjacent the right and left walls  104 ,  106  has embedded therein a C-track  114  that receives rollers  116  (shown in phantom) mounted to an overhead door  118  (shown in phantom). In this exemplary embodiment, the overhead door  118  is retained in its native form just as it was with the conventional, horizontally stored dock leveler. 
         [0044]    Referring to  FIGS. 4 and 5 , the retrofitting includes replacing a horizontally stored dock leveler with a vertical stored dock leveler (VSDL)  120  (not shown in  FIG. 4 ), which is mounted to the pit  102  proximate the rear wall  108 . Proximate the front of the pit  102 , opposite the rear wall  108  is a repositionable pit door  122 . This repositionable pit door  122  has vertical dimensions approximating the depth of the pit  102  and lateral dimensions approximating the width of the pit. 
         [0045]    Referencing  FIGS. 3 ,  4 ,  6  and  7 , the base of the pit door  122  is pivotally mounted to the floor  110  of the pit  102 . Two 90° angle brackets  125  are mounted to the right and left walls  104 ,  106  of the pit  102  so that the corner  127  of each bracket fits within a corresponding corner formed by the interface of the right/left wall  104 ,  106  with the pit floor  110 . Each bracket  125  includes a dowel  129  that extends perpendicularly outward from the left/right wall  104 ,  106 . The dowel  129  is seated within a key-shaped opening  134  that longitudinally extends across a lower portion of the extruded plastic pit seal panel  123 . As will be discussed in more detail hereafter, the pit door  122  is removably mounted to the dowels  129  in order to allow removal of the pit door  122  when the VSDL  120  is vertically stored, so as to allow easier cleaning of the pit  102 . 
         [0046]    Referring to  FIG. 7 , the pit door  122  includes an extruded pit panel  123  having a generally planar front vertical wall  126  spaced apart from a generally planar rear vertical wall  128  by a plurality of linear, longitudinal ribs  130 . Some of the longitudinal ribs  130  extend normally between the front and rear walls  126 ,  128 , while other ribs  130  extend between the front and rear walls  126 ,  128  at obtuse or acute angles. The longitudinal ribs  130  are spaced apart from one another so that longitudinal voids  131  are formed that are generally bounded by adjacent ribs  130  and the front and rear vertical walls  126 ,  128 . The longitudinal ribs  130  are operative to retard substantial deformation of the front and rear walls  126 ,  128  when horizontal contact forces are applied to the walls  126 ,  128 . At the same time, the longitudinal ribs  130  are operative to function as a structural support for the front and rear walls  126 ,  128  so these walls  126 ,  128  are operative to support vertical loads. At the bottom of the panel  123 , longitudinally extending in parallel to the longitudinal ribs  130 , is a key-shaped opening  134 . This key-shaped opening  134  defines a key-shaped rib  136  having opposed tapering surfaces  138  that intersect with a semi-circular surface  140 . The semi-circular surface  140  defines a substantially cylindrical cavity into which the dowels  129  of the angle brackets  125  are received. A pair of detents  142  are formed at the intersection of the tapering surfaces  138  and the semi-circular surface  140  in order to allow the panel  123  to be selectively removed from the dowels  129  and thereafter allow the panel  123  to receive the dowels  129  and thereby selectively reattach the panel  123  to the dowels. Opposite the key-shaped rib  136  is a generally planar top surface  143 , where the top surface  143  and the key-shaped rib  136  sandwich the longitudinal ribs  130  therebetween. In this exemplary embodiment, the lateral/longitudinal ends of the panel  123  remain open. In addition, it is also within the scope of the invention to at least partially fill some or all the voids  131  with insulation. Exemplary forms of insulation include, without limitation, polystyrene foams, polyethylene foams, and latex foams. 
         [0047]    Referring to  FIG. 8 , a keeper  150  is mounted to both the front and rear faces  126 ,  128  proximate the top surface  143  of the panel  123 . In this exemplary embodiment, the keeper  150  comprises a section of angled ¼″ aluminum sheet that is bent at a 35-degree angle to comprise two substantially planar sections  152 ,  154 . The first planar sections  152  of each keeper  150  includes a pair of holes receiving fasteners  158  to mount the keepers  150  to the walls  126 ,  128  of the panel  123  proximate the top surface  143 . It should be understood that the panel  123  includes corresponding through holes (not shown) that are aligned with the through holes of the keepers  150  to accept the fasteners  158 . Exemplary fasteners  158  for mounting the keepers  150  include, without limitation, nuts and bolts. Mounting the keepers  150  to the panel  123  creates a tapered opening above the top surface  143 . Accordingly, as will be discussed in more detail hereafter, the keepers  150  are operative to provide a tolerance and finder system for an overhead door to ensure that when the overhead door is lowered onto the panel  123 , the bottom of the overhead door is longitudinally aligned and seated upon the top  143  of the panel. 
         [0048]    Referring back to  FIG. 7 , in this exemplary embodiment, an aluminum cap  170  is seated upon the top surface  143  and similar aluminum caps (not shown) are seated on the lateral/longitudinal sides of the panel  123 . The aluminum caps  170  extend substantially the entire length on top of the panel and aluminum caps extend substantially the entire height of the panel on each side. Each cap  170  comprises a base surface  174  and a pair of perpendicularly extending legs  175  that collectively define an opening having a rectangular cross-section. This rectangular cross-section approximates the rectangular cross-section of the panel  123  so that the front and rear walls  126 ,  128  of the panel  123  are compression fit within the opening of the cap  170 . Those skilled in the art will realize that the caps  170  may be mounted to the panels  123  using other techniques such as, without limitation, adhesives or mechanical fasteners. In addition, those skilled in the art will realize that the legs  175  of each cap  170  are tapered at 45-degree angles (shown as angle “A”) in order so that the horizontal and vertical caps  170  to abut one another at the corners of the panel  123 . 
         [0049]    Referring to  FIGS. 7 and 9 , opposite the rectangular opening of each cap  170  is a pair of inverted T-shaped cavities  178  defined by corresponding prongs  176 . Each cavity  178  is adapted to receive a corresponding T-shaped projection  180  that extends from a rubber, domed seal  182 . In this manner, the T-shaped projections  180  of the rubber seal  182  (i.e., weatherstripping) are longitudinally fed into the respective inverted T-shaped cavities  178  to mount the seal  182  to the cap  170  so that the seal extends substantially along the entire length of the cap. As will be discussed in more detail hereafter, the domed seal  182  on top of the panel  123  is sandwiched between the panel and the bottom of an overhead door to substantially inhibit air flow between the bottom of the overhead door and the top of the panel  123 . At the same time, the domed seal  182  on both lateral ends of the panel  123  is sandwiched between the panel and the side walls  126 ,  128  of the pit. 
         [0050]    Alternatively, referring to  FIGS. 7 and 10 , the caps  170  on the lateral ends of the panel  123  may only include a single inverted T-shaped cavity  178  to receive a corresponding T-shaped projection  190  that extends from rubber weather stripping  192 . In this manner, the T-shaped projection  190  of the weather stripping  192  is longitudinally fed into the respective inverted T-shaped cavity  178  to mount the weather stripping  192  to the cap  170  so that the weather stripping extends along the entire length of the cap. In this manner, the weather stripping  192  on the sides of the panel  123  contacts the right and left side walls  104 ,  106  of the pit  102  to substantially inhibit airflow between the walls  104 ,  106  and the panel  123 . 
         [0051]    Repositioner #1 
         [0052]    Referencing  FIG. 11 , the repositionable pit door  122  may optionally include an exemplary repositioning device selectively engaged by the VSDL  120  to reposition the panel  123  between a vertical deployment position and a horizontal or near horizontal storage position. Each repositioning device includes at least one engagement device  234  mounted to the interior face  128  of the panel  123 . The engagement device  234  is operative to contact the VSDL  120  so that as the VSDL is lowered, the engagement device overcomes the bias of springs, such as leaf springs  232 , mounted to the pit seal panel  123 . When the panel  123  is in its default upright barrier position (see  FIG. 11 ), the leaf springs  232  provide a bias to maintain the panel in its vertical orientation. 
         [0053]    Each engagement device  234  includes a pair or rollers  236  mounted to opposite ends of an arcuately shaped bracket  238 . In this exemplary embodiment, each roller  236  is freely rotatable with respect to the bracket  238  in order to accommodate a rolling motion against the underside of the VSDL  120 . The bracket  238  includes a through hole that is adapted to receive a pin  244  that also extends through a clevis  242  at one end of an extension  246 . In this manner, the arcuate bracket  238  is operable to pivot with respect to the extension  246  about the pin  244 . As will be discussed in more detail below, pivoting occurs during raising and lowering of the panel  123  as the rollers  236  contact the underside of the VSDL  120 . Finally, the end of the extension  246  opposite the clevis  242  is mounted to the interior surface  128  of the panel  123  using conventional fasteners, such as bolts (not shown). 
         [0054]    As discussed previously, the top of the panel  123  includes the domed seal  182  that is adapted to be correspondingly received within a concave cavity  252  on the bottom of a conventional overhead door  218 . However, it is also within the scope of the disclosure that the bottom of the overhead door  218  be planar or exhibit a convex shape. Regardless of the shape of the bottom of the overhead door  218 , the domed seal  182  closes off gaps between the overhead door  218  and the panel  123  when the overhead door is lowered and the panel  123  is vertically oriented. In exemplary form, many overhead doors  218  have weather-stripping mounted to the bottom in order to form a seal with the ground. Thus, it may be advantageous to remove the weather-stripping from the bottom of the overhead door  218  to form an appropriate connection with the domed seal  182  of the panel  123 . 
         [0055]    Referencing  FIG. 12-15 , when the VSDL  120  is repositioned from its vertical storage position to its horizontal use position, the pit seal  122  is also repositioned so as not to interfere with operation of the VSDL  120 . In operation, as the VSDL  120  is pivoted from its vertical storage position to a horizontal or near horizontal use position, the underside of the VSDL  120  initially contacts the top roller  236  mounted to the arcuate bracket  238  (see  FIG. 12 ). Continued downward movement of the VSDL  120  against the top roller  236  causes the arcuate bracket  238  to pivot with respect to the extension  246 , about the pin  244 , until the bottom roller  236  contacts the underside of the VSDL  120  (see  FIG. 13 ). At this point, the panel  123  remains in its vertical barrier position. But further downward movement of the VSDL  120  against the rollers  236  is operative to push the arcuate bracket  238  downward and correspondingly pivot the bracket  238  about the pin  244  with respect to the extension  246  until the clevis  242  limits the pivoting. 
         [0056]    Referring to  FIGS. 14 and 15 , continued downward movement of the VSDL  120  causes the rollers  236  to roll against the underside of the VSDL toward the pivot point of the VSDL. At the same time, the binding of the clevis  242  against the arcuate bracket  238  pulls the top of the panel  123  rearward toward the pivot point of the VSDL (see  FIG. 14 ). But because the panel  123  is pivotally mounted at the bottom to the dowels  129 , this rearward pulling action is converted into a pivoting action that causes the panel to move from a vertical barrier position toward a horizontal or near horizontal storage position under the VSDL  120 . This pivoting action, caused by direct contact with the VSDL  120 , is operative to overcome the bias of the leaf springs  232  and allow the panel  123  to be pivoted rearwardly. Continued downward movement of the VSDL  120  to approximate its horizontal use position corresponds with the rollers  236  continuing their rolling contact the underside of the VSDL to reach a position that most closely approximates the VSDL pivot point of any position the rollers occupy while in contact with the VSDL. This same rearward most position of the rollers  236  also corresponds to the maximum pivoting or deflection of the panel  123  so that the panel reaches its horizontal or near horizontal storage position (see  FIG. 15 ). An opposite sequence when raising the VSDL  120  to its vertical storage position allows the panel  123  to return to its vertical barrier position, in part, using the bias of the leaf springs  232 . 
         [0057]    Referring back to  FIG. 15 , as the VSDL  120  is raised to its vertical storage position, the pit seal  122  also returns to its default vertical barrier position. In exemplary form, as the VSDL  120  is pivoted upward (compare  FIG. 15  with  FIG. 14 ), the rollers  136  roll against the underside of the VSDL  120 . This is caused by the bias of the leaf springs  232  against the rear of the panel  123 , which correspondingly forces the panel  123 , extension  246 , and bracket  238  upward. Further upward pivoting movement of the VSDL  120  is accompanied by pivoting of the pit seal  122  until both rollers  236  are no longer in contact with the underside of the VSDL  120 , which corresponds with the panel  123  arriving at its vertical barrier position. At this point, only the top roller  236  remains engaged and thus the bottom roller  236  of the bracket  238  pivots toward the interior surface  128  of the panel  123 . Ultimately, the top roller  136  looses contact with the underside of the VSDL  120  as the VSDL is pivoted to more closely approximate its vertical storage position. 
         [0058]    Referring back to  FIGS. 4 and 11 , after the VSDL  120  has cleared the top roller  236  and approximates its vertical storage position, the overhead door  118 ,  218  may be lowered to close off the loading dock  100  opening. In exemplary form, the overhead door  118 ,  218  is lowered so that its bottom engages the top surface of the pit seal panel  123  to close off the loading dock  100  opening. When a conventional panel overhead door  118 ,  218  is fully lowered, the door may be locked in its fully lowered position by repositioning a slide mounted to one of the door panels so that the slide engage an opening (not shown) in the a C-track  114 . Those skilled in the art are familiar with overhead door locks and a further explanation has been omitted for purposes of brevity. When the overhead door  118 ,  218  is in its fully lowered position on top of the pit seal panel  123 , the pit seal panel  123  cannot be pivoted. As a result, locking the overhead door  118 ,  218  in its fully lowered position is likewise operative to lock the pit seal panel  123  in its vertical barrier position. 
         [0059]    It is also within the scope of the invention for the bottom panel of the overhead door  118 ,  218  and/or the pit seal  122  to include fasteners to lock the bottom panel of the overhead door to the pit seal panel  123 . In the alternative, the bottom panel of the overhead door  118 ,  218  and/or the pit seal panel  123  may include dowels that engage corresponding cavities in the opposite structure in order to prohibit the pit seal panel  123  from pivoting inward toward the VSDL when the overhead door  118 ,  218  is fully lowered to contact the top of the pit seal panel  123 , specifically the weatherstripping  182 . 
         [0060]    While the foregoing embodiment has been described with the pit seal  122  being spring biased toward the vertical position so that contact with the VSDL  120  overcomes the spring bias to reposition the pit seal to its nearly horizontal storage position, it is also within the scope of the invention to include a mechanical linkage between the VSDL  120  and the pit seal  122  to pivot the panel  123  downward as the VSDL is pivoted downward, and vice versa. 
         [0061]    Referring to  FIGS. 16 and 17 , a mechanical linkage  300  is operative to reposition the pit seal  122  between its barrier and storage positions. The VSDL  120  is repositionable between a vertical storage position and a horizontal use position. Structurally, the VSDL  120  includes a plurality of structural braces  320  that extend linearly underneath decking  304 , which provides a working surface when the VSDL is in its horizontal use position. A pair of outermost flanges  306  extend perpendicularly from an edge of the decking  304  and underneath the decking. These outermost flanges  306  are inset within the pit  102  when the VSDL  120  is in its horizontal use position. At the same time, one of the outermost flanges  306  includes a through hole that receives a bolt  310  of the mechanical linkage  300  to physically connect the VSDL to the pit seal  122 . 
         [0062]    An exemplary mechanical linkage  300  includes an arcuate, right angled bracket  314  fabricated from quarter-inch bar stock. One end of the bracket  314  includes a through hole that receives the bolt  310  concurrently extending through one of the outermost flanges  306  in order to mount the bracket to the flange. An opposite end of the bracket  314  also includes a through hole receiving a ball of a ball joint coupling  318 . The ball of the ball joint coupling  318  is secured to the bracket  314  using a conventional nut (not shown). A complementary half of the ball joint coupling  318  includes a threaded control arm  316  which is mounted to a threaded cylindrical tube  324  at an opposite end. Another end of the cylindrical tube  324  is welded to a section of bar stock  330  having a circular opening (not shown) formed at an end opposite the cylindrical tube  324 . This circular opening receives a cylindrical pin  334  that is mounted to a right angle bracket  336 . This right angle bracket  336  is mounted to the front wall  126  of the repositionable panel  123 . In this exemplary embodiment, the pin  334  extends slightly laterally beyond the panel  123  just enough to extend through the circular opening of the bar stock  330 . The end of the pin  334  that extends beyond the bar stock  330  may include a linchpin or some other means to maintain the pin  334  within the opening in the bar stock  330  as the VSDL  120  is repositioned between its horizontal use position and its vertical storage position. 
         [0063]    Referring to  FIGS. 18-21 , an exemplary sequence of repositioning the pit seal  122  from its vertical barrier position to its near horizontal storage position begins with raising any overhead door out of the line of travel of the VSDL  120 . Thereafter, the VSDL  120  is pivoted proximate the rear of the pit (see  FIG. 16 ) so that the decking goes from a vertical storage position (see  FIG. 18 ) to a horizontal use position (see  FIG. 21 ). During the pivoting of the VSDL  120 , the mechanical linkage  300  concurrently attached to the panel  123  and the VSDL  120  is operative to transfer the downward pivoting motion of the VSDL into downward pivoting motion of the panel. In other words, as the VSDL  120  is pivoted downward, from vertical to horizontal, so too are the outermost flanges  306 . Also, because the one of the flanges  306  is rigidly mounted to the bracket  314 , pivotal movement of the flange also results in pivotal movement of the bracket. The arcuate nature of the bracket  314  works with the arcuate path of the bolt  310  to convert the arcuate motion of the VSDL  120  into horizontal pulling motion on the threaded control arm  316 , the threaded cylindrical tube  324 , and the bar stock  330 . This horizontal pulling motion of the bar stock  330  is transferred to the panel  123  by way of the pin  334  and the right angle bracket  336 . Because the bottom of the panel  123  is pivotally mounted to the floor of the pit, horizontal movement at the top of the panel  123  is converted into pivotal motion of the entire panel  123 . The sequence of motion to reposition the pit seal panel  123  from a vertical barrier position to a near horizontal storage position is shown by a series of snapshots as depicted in  FIGS. 18-21 . Conversely, raising the pit seal panel  123  from its storage position to its barrier position occurs as the VSDL  120  is pivoted from a horizontal to a vertical storage position. While the foregoing exemplary embodiment has used a solid mechanical linkage, other forms of linkage may be utilized to reposition the pit seal panel  123  responsive to motion of the VSDL  120 . 
         [0064]    Referring now to  FIGS. 22 and 23 , in exemplary form, the pit seal panel  123  may be spring biased using a torsion spring  350  mounted concurrently to the panel and to the pit wall. In this exemplary embodiment, the panel  123  is biased toward its vertical barrier position. However, a cable  356  is concurrently mounted to the VSDL  120  and the panel  123  using separate pulleys  352 ,  354 . Each of the pulleys  352 ,  354  is rigidly attached to either the VSDL  120  or the panel  123  so that pivoting motion of the VSDL  120  and panel  123  is correspondingly transferred to the respective pulley as rotational motion, and vice versa. In this fashion, as the VSDL  120  is pivoted downward from its vertical storage position and toward its horizontal use position, the pulley  352  mounted to the VSDL is rotated in a clockwise fashion. This clockwise rotation is operative to pull on the cable  356  toward the first pulley  352  and away from the second pulley  354 . As a result, the cable  356  necessarily transfers the clockwise rotation of the first pulley  352  into counterclockwise rotation of the second pulley  354 . This counterclockwise motion of the second pulley  354  causes the panel  123  to pivot rearward toward the VSDL  120 , which is resisted by the torsion spring  350 . But the force on the cable  356  is large enough to overcome the spring bias exerted by the torsion spring  350 , thereby repositioning the panel  123 . In this manner, continued rotation of the first pulley  352  from the pivoting of the VSDL  120  is operative to continue pulling on the cable  356  and continue rotating the second pulley  354  until the VSDL reaches its horizontal use position (see  FIG. 23 ). 
         [0065]    It is also within the scope of the disclosure to include a servo motor (not shown) coupled to the first pulley  352  or the second pulley  354  instead of the VSDL  120 . A feedback control sensor (not shown) would detect downward and upward pivoting motion of the VSDL and cause the servo motor to rotate the pulley(s)  352 ,  354  clockwise or counterclockwise to raise or lower the panel  123 . In exemplary form, the sensor may be tied into the control panel of the VSDL  120  to directly sense instructions to the hydraulic motors of the VSDL  120  and respond appropriately with the correct servo motor motion in order to properly position the panel  123  between a vertical barrier position and a near horizontal storage position. Those skilled in the art are familiar with control panels for VSDLs and a detailed discussion of this feature has been omitted only for purposes of brevity. 
         [0066]    Repositioner #2 
         [0067]    Referring to  FIGS. 24-26 , a further exemplary repositionable pit seal  400 , in contrast to the foregoing exemplary embodiments, is repositionably mounted to the bottom of a conventional overhead door  402 . In this exemplary embodiment, the repositionable pit seal  400  comprises a pit seal panel  404  that is pivotally mounted to the bottom panel of an overhead door  402  via a pair of hinges  406 . 
         [0068]    As shown in  FIG. 25 , the construction of the pit seal panel  404  is similar to the pit seal panel  123  of the foregoing exemplary embodiments. Specifically, the pit seal panel  404  may be fabricated from an extruded polymer or metal and includes a generally planar front face sheet  408  and rear face sheet  410 . The front face sheet  408  is adapted to face outward, away from interior of the building housing the pit  102 , while the rear face sheet  410  is adapted to face the interior of the building. The face sheets  408 ,  410  are interposed by a series of walls  412  that extend longitudinally along the length of the panel  404 . As can be seen from  FIG. 25 , these walls  412  are angled at various degrees to provide structural support to the face sheets  408 ,  410 . Together, the walls  412 , and face sheets  408 ,  410  define a series of longitudinal cavities  414  extending through the panel  404 . Depending upon the end application, such as in a refrigerated building, the cavities may include an insulating material such as, without limitation, latex or acrylic foam. 
         [0069]    The top  416  and bottom  418  of the panel  404  are substantially flat and have mounted thereto a weather-strip retainer  420  having a pair of inverted T-shaped cavities. These inverted T-shaped cavities are adapted to receive the corresponding T-shaped ends of weather-stripping  422  to secure the weather-stripping to the weather-strip retainer  420 . At least one opening (not shown) is formed through the bottom  418  of the panel  404 , the weather-stripping retainer  420 , and the weather-stripping  422  in order to accommodate throughput of at least one retainer pin  424 . 
         [0070]    In this exemplary embodiment, two retainer pins  424  are mounted within corresponding openings in the floor  110  of the pit  102 . The retainer pins  424  operate to inhibit lateral movement of the lower portion of the panel  404  when the pins  424  are secured within the openings  426  in the panel. In exemplary form, the panel  404  also includes weather-stripping retainers  420  and weather-stripping  422  along the lateral/longitudinal sides, thereby forming a weather-stripping perimeter around the panel. 
         [0071]    Alternatively, or in addition to utilizing the retainer pins  424 , the pit  102  may include a pair of tapered or U-shaped guides  430  to precisely guide the panel  404  into position as the panel is lowered into the pit  102  and into its barrier position. Each guide  430  is bolted to the floor  110  of the pit  102  and is positioned adjacent to the right and left side walls  104 ,  106 . Accordingly, any attempt to dislodge or laterally remove the panel  404  from outside is inoperative because the guides  430  and pins  424  cooperate to retain the panel  404  laterally in position. With that said, the panel  404  may be not be repositioned vertically if the overhead door  402  is locked in its furthermost lowered position. Yet when the overhead door  402  is raised, so too is the panel  404  raised. However, in order to maintain the vertical clearance of the original overhead door  402 , the panel  404  is selectively repositionable. 
         [0072]    The exemplary repositionable pit seal  400  includes a pneumatic cylinder or linear actuator  440  concurrently mounted to the overhead door  402  and the pit seal panel  404 . A pair of angle brackets  442  are vertically oriented and mounted to the overhead door  402  in a spaced apart fashion. Each of the angle brackets includes a plurality of through holes that are adapted to receive a rod  444  to secure the cylinder end of the pneumatic cylinder  440 . The opposite end of the pneumatic cylinder  440  is mounted to the panel  404  using a rod  446  and a pair of angle brackets  448 . The angle brackets  448  mounted to the panel  404  are vertically oriented and spaced apart to accommodate the piston of the pneumatic cylinder  440 . Again, similar to the brackets  442  mounted to the overhead door, the brackets  448  mounted to the panel  404  include a series of vertically distributed through holes to accommodate different throughput locations of the rod  446 . 
         [0073]    In operation, the repositionable pit seal  400  may be repositioned between a barrier position (see  FIG. 24 ) and an egress position (see  FIG. 26 ). By way of exemplary explanation, repositioning the pit seal  400  from its barrier position to its egress position includes unlocking the overhead door  402  from the adjacent C-track  114 . Presuming the overhead door  402 , and the rollers  116  mounted thereto, are able to be repositioned with respect to the C-track, the overhead door may be raised using a conventional overhead door lift system (not shown). As the overhead door  402  is raised, so too is the pit seal  400 . As the pit seal panel  404  is vertically raised, the lateral ends to the panel initially follow the track of the guides  430  and allow the panel to be raised vertically over the pins  424 . As soon as the panel  424  clears the pins  424  and guides  430 , the pneumatic cylinder or linear actuator  440  may be engaged to pivot the panel with respect to the overhead door  402 . 
         [0074]    By way of example, the pneumatic cylinder or linear actuator  440  allows the panel  424  to be pivoted anywhere between 0-135 degrees (either inward or outward) with respect to the overhead door. As shown in  FIG. 26 , the panel  424  is pivoted outward approximately 90 degrees from the bottom section of the overhead door  402 . In this position, the clearance otherwise obtainable by the overhead door  402  prior to attaching the panel is nearly the same as that achieved when the panel is pivoted 90 degrees with respect to the overhead door. However, those skilled in the art will understand that pneumatic cylinder or linear actuator  440  is optional as it may not be necessary to pivot the panel with respect to the door such as circumstances where clearance is not an issue. In exemplary form, the pneumatic cylinder or linear actuator  440  includes an electronic controller (not shown) and other appropriate sensors and electronics as will be known to those skilled in the art and programmed to reposition the panel  404  as the overhead door  402  is repositioned. 
         [0075]    Repositioning the pit seal  400  to its barrier position includes a similar sequence of events performed in reverse order. For example, as the overhead door  402  is initially lowered from its overhead storage position, the panel  404  is pivoted to be vertically aligned with the overhead door, the guides  430 , and the pins  424 . After the panel  404  is vertically aligned with the door  402 , the door may be further lowered so that the bottom of the door reaches the floor  117  of the building. As the overhead door  402  reaches the floor  117  of the building, the lower portion of the panel  404  is positioned adjacent to the floor  110  of the pit  102 . Thus, the combination of the panel  404  and overhead door  402  is operative to close off the entire loading dock opening. 
         [0076]    Following from the above description and invention summaries, it should be apparent to those of ordinary skill in the art that, while the methods and apparatuses herein described constitute exemplary embodiments of the present invention, the invention contained herein is not limited to this precise embodiment and that changes may be made to such embodiments without departing from the scope of the invention as defined by the claims. Additionally, it is to be understood that the invention is defined by the claims and it is not intended that any limitations or elements describing the exemplary embodiments set forth herein are to be incorporated into the interpretation of any claim element unless such limitation or element is explicitly stated. Likewise, it is to be understood that it is not necessary to meet any or all of the identified advantages or objects of the invention disclosed herein in order to fall within the scope of any claims, since the invention is defined by the claims and since inherent and/or unforeseen advantages of the present invention may exist even though they may not have been explicitly discussed herein.