Abstract:
The present invention provides a sealing structure for a loading dock opening, consisting of two flexible side seals on opposite sides with a sealing form and mounted in a vertical orientation to a frame, and a curtain-like head seal also affixed to the frame, which is affixed to the loading dock walls. Taken together, the sealing structure sealingly engages the cargo body such that weather elements do not enter the warehouse or truck body but goods can be moved between the cargo body and the warehouse. The seal is deformable but resilient, forming a seal when in contact with the truck cargo body, which has shape memory and stiffness to revert to its original form when it no longer contacts the truck cargo body. 
     The present invention also provides in one embodiment of the present invention, side seals mounted in a vertical orientation on each side of the loading dock entrance, an outer layer forming a sealing shape, typically that of a teardrop, in profile. It may contain one or more reinforcing strips within it, as well as a foam core, both of which help it to maintain its teardrop shape, even after frequent contact with a truck cargo body. The side of the side seal opposite the rounded portion of the teardrop comes together, forming a mounting flange, which is mounted by means of bolts to a metal frame, which in turn is mounted to the loading dock wall.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to sealing structures for applications to the periphery of a door or like opening and more specifically to heavy duty sealing structures for loading dock shelters that form an environmental seal between the warehouse interior and the exterior environment. 
     2. Background of the Invention 
     Loading docks contain doors that allow access from the exterior to the interior of a warehouse or other storage facility, and are used for loading and unloading cargo from freight trucks. Trucks reverse against the loading dock, and the sides and top may contain sealing structures which attempt to seal the cargo body of the truck such that the elements do not enter the warehouse and goods can then be moved between the cargo body and the warehouse. The seals attempt to prevent snow and rain from entering, but also attempt to reduce air exchange, for instance cold outside air from entering a heated warehouse, as well as preventing uncomfortable drafts. 
     Sealing structures of the above-mentioned general type are known in the art. Dock shelters consist of a framework that extends up to three feet out from the loading dock wall, and curtains may hang from this frame to drape over the top and either side of the docked cargo body. However, these curtains tend to be limp and may create a poor appearance. While acceptable in milder climates, they may not seal optimally in a windy or cold environment. Other arrangements include foam pads to which the cargo bodies are backed, and which seal as a result of compression of the foam. While these provide a seal, they are not ideal because the foam is prone to wear from contact with the cargo bodies and cargo doors. Additionally, foam seals may be more expensive than traditional dock shelters, and may reduce the access area of the trailer because the foam pads overlap the perimeter of the cargo body. 
     A further arrangement is shown in U.S. Pat. No. 4,359,846 which has three flexible sealing elements along the top and sides of the loading dock entrance, which are movable from an inoperative position flush with the loading dock entrance, to an operative position which attempts to seal the loading dock entrance into the truck cargo body. This configuration requires effort to extend the sealing lamellas into the cargo body which is not practical and causes further delay in the loading or unloading of a cargo body. As well, the seal is maintained by the use of springs which hold the lamellas in contact with the truck body, which are subject to mechanical breakdown and increased cost of manufacture. 
     It is also known to subdivide the flexible walls into several individual lamellas which are arranged parallel to one another, in order to provide improved matching of the walls to the outer contour of the container, such as is described in U.S. Pat. No. 5,333,424. The lamellas in this configuration are prone to abuse by the truck cargo bodies which reverse against them as several lamellas are held in a compressed state over the entire period of use. Furthermore, the lamellas are also prone to tearing with the uneven edges of the cargo body or the cargo doors, which fold around the side of the cargo body when fully open. 
     U.S. Pat. No. 3,854,257 discloses a sealing structure which is composed, on each side of the loading dock, of two sheets of flexible material, the front sides being joined together face to face, secured at one side, with the opposite sides bent backwards and secured to the loading dock to create a bumper that compresses when the truck contacts it. This design has shortcomings in that it uses two pieces to form the seal, making it mechanically complex and expensive to manufacture, and the inner joint is subject to wear leading to breakdowns. Similar disadvantages as outline above are present in this application as seals are maintained in a compressed state during any use which leads to the seals deteriorating quickly. 
     A further arrangement is disclosed in U.S. Pat. No. 6,948,285, wherein a dock shelter is described with face panels on both sides and on top, which are moveable for sealing against vehicles of various sizes. This arrangement is more durable than foam, but due to the use of springs it is mechanically complex, therefore less robust as well as expensive to manufacture. 
     Based on the above, there is a need for a sealing structure that will sealingly engage with a container regardless of the openings of the container to unload and load cargo. The present invention provides a sealing structure which allows the container to be environmentally sealed to the area of loading or unloading within a building, and addresses the shortcomings identified in the prior art by being less expensive to manufacture, more durable and a having a greater service life. The sealing structure of the present invention also does not require the use of a significant and considerable compression force to be exerted by the cargo body to maintain a sealing environment. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment of the present invention, a sealing structure for a loading dock opening, consisting of two side seals on opposite sides with a sealing form and mounted in a vertical orientation to a frame, and a curtain-like head seal also affixed to the frame, which in turn is affixed to the loading dock walls. Taken together, the sealing structure sealingly engages the cargo body such that weather elements do not enter the warehouse or truck body but goods can be moved between the cargo body and the warehouse. The seal is deformable but resilient, forming a seal when in contact with the truck cargo body, which has shape memory and stiffness to revert to its original form when it no longer contacts the truck cargo body. 
     In one embodiment of the present invention, side seals are mounted in a vertical orientation on each side of the loading dock entrance, an outer layer forming a sealing shape, typically that of a teardrop, in profile. It may contain one or more reinforcing strips within it, as well as a foam core, both of which help it to maintain its teardrop shape, even after frequent and prolonged contact with a truck cargo body. The side of the side seal opposite the rounded portion of the teardrop comes together, forming a mounting flange, which is mounted by means of bolts to a metal frame, which in turn is mounted to the loading dock wall. 
     The head seal consists of a curtain-like structure which hangs down from the structural frame, and sealingly engages a truck cargo body when it backs into the sealing structure. It drapes over the rear of the cargo body so as to create an environmental seal between the warehouse and the exterior that is able to accommodate height changes in the truck cargo body due to changing loads. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the structural frame as required for the present invention affixed to a building having a loading dock, according to one embodiment of the present invention; 
         FIG. 2  is a perspective view of the structural frame with flexible seals and head seal attached to the structural frame according to one embodiment of the present invention; 
         FIG. 3A  is a front view of an application of the sealing structure according to one embodiment of the present invention; 
         FIG. 3B  is a perspective view of an application of the sealing structure according to one embodiment of the present invention; 
         FIG. 4  is a detailed view of a flexible seal showing the components of the seal while being affixed to the structural frame according to one embodiment of the present invention; 
         FIG. 5  is a perspective view of a flexible seal of the present invention secured to the structural frame and according to one embodiment of the present invention; 
         FIG. 6  is a detailed top view of a flexible seal secured to the structural frame according to one embodiment of the present invention; 
         FIG. 7A  is a top view of a flexible seal in a semi-disassembled state according to one embodiment of the present invention; 
         FIG. 7B  is a side view of a side seal in a semi-disassembled state according to one embodiment of the present invention; 
         FIG. 8  is a top view of an application of the present invention affixed to a building having a loading dock absent the head seal according to one embodiment of the present invention; 
         FIG. 9  is a top view of an application of the present invention affixed to a building having a loading dock according to one embodiment of the present invention; 
         FIG. 10  is a side view of an application of the present invention affixed to a building having a loading dock with a truck cargo body docked to it according to one embodiment of the present invention; 
         FIG. 11  is a front view according to one embodiment of the present invention wherein frontal means to retain is positioned on a flexible seal according to one embodiment of the present invention; and 
         FIG. 12  is a detailed view of frontal means to retain as shown in  FIG. 11  according to one embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention will now be described more fully hereinafter with reference to the accompanying figures, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. 
     With reference to  FIG. 1  and according to one embodiment of the present invention, a building having a building wall  10  is shown having an opening in the form of a loading dock opening  20 . A structural frame  30  is shown positioned and fixed to the building wall  10  in proximate relationship to the loading dock opening  20 . The structural frame  30  is required to secure the other elements of the sealing structure of the present invention. A worker skilled in the relevant art would be familiar with the various types of materials that can be used to fabricate and erect such a structural frame for example, aluminum, steel or any other suitable types of construction materials. The structural frame  30  is secured to the building wall  10  through various securing means as would be known by a worker skilled in the relevant art. 
     With reference to  FIG. 2  and according to one embodiment of the present invention, the structural frame  30  is shown with flexible seals  40  and  50  secured to it. A flexible head seal  60  is also secured to structural frame  30  wherein the top sections of flexible seals  40  and  50  are concealed behind head seal  60  as shown by dotted lines. These three seals combine together to sealingly engage with a cargo body (not shown) to environmentally seal the cargo body (not shown) with the building wall  10 . With further reference to  FIG. 2 , protective guards  70  and  75 , which are typical components of a loading dock, are positioned at the bottom of structural frame  30  and flexible seals  40  and  50 . A flexible side guard  80  is also shown in  FIG. 2  and further described below. 
     With reference to  FIG. 3A  and according to one embodiment of the present invention, the building wall  10  circumscribes a loading dock opening  20  permitting access from the exterior to the interior of the building. Structural frame  30  is mounted on the building wall  10  with a first and second flexible side seals  40  and  50  mounted on the structural frame  30  opposite one another. A head flexible seal  60  is positioned above the flexible side seals  40  and  50  to seal the top of a cargo body (not shown). The side seals  40  and  50  are mounted so that the projecting rounded sides define a width slightly less than that of a cargo body (not shown). 
     With further reference to  FIG. 3A , a protective cover  90  is positioned above head seal  60  according to one embodiment of the present invention. The protective cover  90  also has visual indicators in the form of reflective stripes  100  for guiding a truck driver during the alignment and centering of a truck&#39;s cargo body (not shown) within the loading dock opening  20 . When the truck cargo body (not shown) reverses into the side seals  40  and  50 , said seals  40  and  50  will be displaced and deform elasticly and resiliently into the loading dock opening  20  as a result of the displacement force exerted by the cargo body (not shown), all the while maintaining contact on the cargo body (not shown) as a result of their elasticity. The side seals  40  and  50  have a sealing form which is a teardrop cross-sectional shape that provides resilient elasticity and durability and is further described below. A person skilled in the art would know that other sealing forms may be used, such as an oval cross-sectional shape, while achieving the intended result. The side seals maintain a small pressure and constant contact in order to bring about a seal between the sides of the cargo body (not shown) and the structural frame  30 . The head seal  60  is in the form of a curtain of PVC plastic which hangs down from the top portion of the structural frame  30 . When the cargo body (not shown) is positioned within the sealing structure of the present invention, the head seal  60  drapes from the frame  30  over the top rear of the cargo body (not shown), creating an environmental seal. While the side seals  40  and  50  and head seal  60  together form an environmental seal between the truck cargo body and the warehouse located within the loading dock, seals  40 ,  50  and  60  are not bumpers and do not prevent a cargo body from backing into the dock  20 . 
     With further reference to  FIG. 3A , an eavestrough  110  is position on the top surface of the structural frame  30 . The presence of eavestrough  110  allows the channeling of water away from the cargo body (not shown) and may dissipate the water along the sides of structural frame  30 . 
     With reference to  FIG. 3B  and according to one embodiment of the present invention, flexible side seals  40  and  50  are shown attached to a structural frame  30  proximate to a dock opening having a door  120  and a loading plate  125 . The flexible side seals  40  and  50  also operatively contact the flexible side guard  80  when a cargo body (not shown) is positioned within the sealing structure of the present invention. Securing means in the form of aluminum angles  130  and  140  secure the side seals  40  and  50  to structural frame  30 . Head seal  60  is secured to structural frame  30  through the use of screws or any other manner as would be known by a worker skilled in the relevant art. The securing means used to secure head seal  60  are positioned underneath protective skirt  90 . Protective guards  70  and  75  are also shown at the bottom of structural frame  30 . Reflective stripes  100  may also be located on the side seals  40  and  50  and protective skirt  90  to further assist in the alignment and centering of a cargo body (not shown) within the sealing structure of the present invention. 
     With reference to  FIG. 4  and according to one embodiment of the present invention, a flexible side seal  40  is secured to a section of structural frame  30 . The flexible seal  40  is secured to the structural frame  30  through a flange mounting section  150  of the flexible seal  40 . Securing means in the form of an aluminum angle  130  is then positioned over the flange mounting section  150  and structural frame  30  in order to secure the flexible seal  40  to the structural frame  30 . A screw  160  is positioned through the aluminum angle  130  in order to secure the flange section  150  of the flexible seal  40  to the frame  30  wherein the screw  160  passes through the flange mounting section  150  of the flexible seal  40 . The use of a flange and screw are well known engaging means to secure components to one another. A worker skilled in the relevant art would be familiar with other means such as for example, nuts and bolts, nails or even super glue. A worker skilled in the relevant art would also be familiar with the number and size of screws required to properly secure a flexible seal to a structural frame as shown. 
     With further reference to  FIG. 4 , foam material  170  is positioned within the teardrop section of flexible seal  40 . As will be described later, the teardrop section of the flexible seal  40  can be entirely filled with pre-shaped teardrop foam or may have a number of foam sections within the length of flexible seal  40 . 
     With further reference to  FIG. 4 , retaining means  180  is shown having a first end  190  affixed to the flexible seal  40  and an opposite end  200  affixed to structural frame  30 . The retaining means  180  may be constructed of cloth-covered rubber cord, also known as “bungee cord”, or may be manufactured of a variety of other materials while achieving the same result as would be appreciated by a worker skilled in the relevant art. The retaining means as shown in  FIG. 4  is a bungee cord in an extended position which allows for the flexible seal  40  to be in a rest position. The presence of the retaining means  180  prevents the flexible seal  40  from further extending away from the structural frame  30  while in a rest position. Without the presence of this retaining means  180 , flexible seal  40  could extend away from the structural frame  30  which would negatively impact the functionality of the flexible seals of the present invention in operation. 
     With further reference to  FIG. 4 , the retaining means  180  is fastened to the flexible side seal  40  by first having a knot  210  at bungee cord end  190 . The knot  210  is sufficiently large to prevent the knotted end  210  from being pulled through opening  130  in side seal  40 . Opposite end  200  is fastened to the frame  30  by a hook  220 . A person skilled in the art would be familiar with various fastening means that may be employed to fasten the bungee cord  180  between the side seal  40  and the structural frame  30  to achieve the intended result. A worker skilled in the relevant art would also be familiar with the material selected to manufacture the flexible side seals to ensure adequate rigidity sufficient to secure retaining means to the side seal and the structural frame. 
     With reference to  FIG. 5 , and according to one embodiment of the present invention, a flexible seal  40  of the present invention is shown affixed to a structural frame  30  wherien the entire structural frame is not shown as in  FIG. 1 . The flange mounting section  150  of the flexible seal  40  is secured to structural frame  30 . The securing means utilized to secure the flange mounting section  150  to the structural frame  30  are similar as described under  FIG. 4  and consist of an aluminum angle  130  secured with screws  160 . 
     With further reference to  FIG. 5 , visual indicators in the form of a reflective stripe  100  may be present on the lower portion of flexible side seal  40 , or may extend the length of the flexible side seal  40 , and is generally located in the center of the front of the flexible side seal  40 , such that it may aid drivers in positioning truck cargo bodies, who see the reflective stripes  100  in their side-view mirror. In one embodiment of the present invention, the flexible side seal  40  is reinforced by one or more sections of a second reinforcing layer  270  as shown by the dotted lines. The reinforcing layers  270  aid in maintaining the flexible side seal  40  in a teardrop shape and provides added rigidity and durability. In a preferred embodiment, the reinforcing layer  270  is present in the entire length of side seal  40 . In another embodiment, the reinforcing layers  270  are only present at the top and the bottom of side seal  40  as shown in  FIG. 5  in order to increase the rigidity of the impact areas on flexible seal  40  as exerted by the top and bottom of a cargo body (not shown). A person skilled in the art would appreciate that there may be one or more sections of reinforcing layers  270  spaced along the length of the interior of the side seal  40 , any configuration achieving the intended result. In another embodiment of the present invention, reinforcing layers may be absent in order to manufacture a less expensive flexible side seal. A more detailed description of the flexible seal  40  is provided below. 
     With reference to  FIG. 6  and according to one embodiment of the present invention, a detailed view of a flexible seal  40  is shown as secured to structural frame  30 . The flexible seal  40  is constructed of a resilient, sheet-like cover layer  240  having a first edge  250  and a second edge  260 . The cover layer is made from a heavy-duty PVC plastic or any other suitable material as would be known by a worker skilled in the relevant art and suitable for various climatic conditions. The first edge  250  and second edge  260  are positioned atop one another to create a flange mounting section  150  on the flexible seal  40 . The presence of flange mounting section  150  allows for the flexible seal  40  to be secured to structural frame  30 . 
     With further reference to  FIG. 6 , a reinforcing layer  270 , in one embodiment also made from heavy-duty PVC plastic, lies within, and follows the tear-drop shape of, the cover layer  240 . The reinforcing layer  270  also has a first reinforcing layer edge  280  and a second reinforcing layer edge  290 . The first reinforcing layer edge  280  coincides with the first edge  250  of the cover layer  240 , and lies within the mounting flange section  150 . The second reinforcing layer edge  290  does not extend into the mounting flange section  150 . The interior of flexible seal  40  is filled with a shaped foam insert  170  as previously described, which helps to maintain the shape of the seal despite frequent, extended contact with a cargo body (not shown), during its operational life. A pull strip  300  is affixed to either side of the shaped foam insert  170 , such that it overlaps at the narrow end of the tear-drop shape. A worker skilled in the relevant art would be familiar with the various lengths and types of pull strip material required to ensure a stable and durable structure. The pull-strip  300  during assembly of the flexible seal  40  is positioned between edges  280  and  260  and within the mounting flange section  150 . The presence of pull strip  300  also allows for the positioning of the foam insert  170  within the flexible seal  40  as separate sections of foam could be inserted within the flexible seal  40  or an entire section of foam could be inserted as shown. A worker skilled in the relevant art would be familiar with the various aspects of foam insert possible within the flexible seals. The mounting flange section  150  is then affixed to the structural frame  30  by an aluminum angle  130  and a series of bolts  160  (only one shown). 
     With reference to  FIG. 7A  and according to one embodiment of the present invention, a flexible seal is shown in a semi-disassembled state. The cover layer  240  is positioned flat on a surface and presents an elongated rectangle with edges  250  and  260 . Reinforcing layers  270  are placed selectively on the cover layer  240 , and may consist of two strips only at the top and bottom, or may consist of one strip only in the middle, or may consist of various strips strategically placed along the length of the cover layer  240 , or may consist of a single layer which coincides with the entire length of cover layer  240 , such that it is, in effect, a double-layer cover layer as previously described. The pre-shaped teardrop foam insert  170  is formed of three foam blocks in the present embodiment. A pull-strip  300 , which is glued onto the pre-shaped foam inserts  170  at the small end of the its teardrop profile and further described in  FIG. 7B  is secured to the cover layer  240 . 
     With further reference to  FIG. 7A , a first series of openings  310  along edge  250  and a second series of opening  310  along edge  260  provide means to secure the flexible seal to the frame structure for example through the use of bolts or screws and an aluminum angle (all not shown). During manufacturing, edges  250  and  260  are aligned and positioned atop one another thus aligning the series of openings  310  from both edges  250  and  260  to perfectly coincide with one another. During this step, the entire cover layer  240  is bent in half along its longer axis such that the series of openings  310  from each edge  250  and  260  coincide, and in this manner a side seal  40  employing a tear-drop cross-sectional profile is assembled. A person skilled in the art would appreciate that different methods of assembly could be employed to produce side seals with different cross-sectional profile shapes. 
     With reference to  FIG. 7B , the foam insert  170  is secured to the cover layer  240  through the pull strip  300  which is secured to the cover layer through the use of a super adhesive material such as glue or such as would be known by a worker skilled in the relevant art. The pull strip  300  extends on each side of the foam insert  170  to further secure the foam in place within the flexible seal. The reinforcing layer  270  extends only up to the foam insert  170  and does not extend the entire length of the cover layer  240 . 
     With further reference to  FIG. 7B , the foam insert  170  lies on top of the reinforcing layer  270  and the cover layer  240 . On each side of the narrow end of the pre-shaped foam&#39;s  170  tear-drop shape is glued the pull strip  300 , which overlaps the narrow end of the pre-shaped foam insert  170  such that the end of the pull strip  300  coincides with the side of the cover layer  240  and reinforcing layer  270 . 
     With reference to  FIG. 8  and according to one embodiment of the present invention, various components of the sealing structure of the present invention are shown. Flexible seals  40  and  50  are shown and affixed to the structural frame  30 . A cargo trailer  330  is positioned between both flexible seals  40  and  50 . The flexible side seals  40  and  50  are compressed due to the advent of the cargo trailer  330  applying a displacement force and some pressure to the front of the flexible side seals  40  and  50 . Means to retain in the form of retaining cords  340  and  350  appear in a relaxed position as the flexible side seals  40  and  50  are displaced and deformed in a direction towards the interior of the loading dock opening  20 . The elasticity of the flexible side seals  40  and  50  hold it against the cargo body  330 , so that it is able to form a seal between the cargo body  330  and the frame  30  and, consequently, the building wall  10 . When in a sealed, or compressed, position, the retaining cords  340  and  350  are in a relaxed or slack position since the unextended cords are now longer than the distance between the points of fastening of the retention cords  340  and  350  in the flexible side seals  40  and  50 , and the frame  30 . 
     With reference to  FIG. 9  and according to one embodiment of the present invention, a cargo body  330  having its rear doors  360  and  370  in an open condition and positioned along the sides of the cargo body  330  is positioned within the sealing structure such that the side seals  40  and  50  are in a sealed position. The frame is composed of a front plate  380  and several galvanized steel struts  390  that are affixed to the building wall  10 . The frame is sealed by a protective layer (not shown) of PVC plastic which lies on top of struts  390  and is affixed to both the front plate  380  and the building wall  10 , environmentally sealing the interior of the building from the exterior. The head seal  60  hangs from the front plate  380  and rest on the top surface of the cargo body  330 . 
     With reference to  FIG. 10  and according to one embodiment of the present invention, the head seal  60  is moved in a sealing position when the cargo body  330  is docked. The length of the head seal  60  hangs down which allows it to drape over the top surface of the cargo body  330  forming an environmental seal between the warehouse and the exterior. As the length of the head seal  60  is longer than the distance between the front plate and the truck cargo body  330 , the head seal  60  is able to accommodate a variety of truck cargo body heights. The head seal&#39;s flexibility inherent in its curtain-like structure allows the environmental seal to be maintained in the face of height changes in the truck cargo body that progressively occur as the load changes with unloading or loading. A worker skilled in the relevant art would also be familiar with the use of precise slits positioned with head seal  60  to allow greater flexibility and applicability of head seal  60  in order to minimize tearing of the head seal. The presence of such slits in head seal  60  are shown in  FIG. 1 . 
     With reference to  FIG. 11  and according to one embodiment of the present invention, a frontal means to retain  350  may be position on the front portion of a flexible side seal  40 . The presence of frontal means to retain may facilitate the return of the flexible seal  40  in a rest position once a cargo body is displaced from the sealing structure of the present invention. A worker skilled in the relevant art would be familiar with various manners available to provide this additional means to retain such as a bungee cord or a spring like mechanism as shown in  FIG. 11 . 
     With reference to  FIG. 12 , the frontal means to retain  350  as described in  FIG. 11  is shown with a first end  360  of means to retain  350  attached to structural frame  30  and opposite end  370  of means to retain  350  attached to the side seal  40 . A worker skilled in the relevant art would be familiar with various means available to secure either ends  360  and  370  to either the structural frame  30  or side seal  40  such as a hook, screws, super adhesive glues or even a knot based on the nature of the means to retain means used as defined previously. 
     Many modifications and other embodiments of the invention will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing description and associated drawings. Therefore, it is understood that the invention is not to be limited to the specific embodiment disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.