Abstract:
In order to provide a durable loading dock shelter with an effective seal, the dock shelter is provided with a face panel that is relatively lightweight and firm, yet moveable for sealing against vehicles of various size and position. The face panel can be used as a side curtain or a head curtain. To provide the face panel with durability while minimizing its weight, the face panel is thermoformed of twin sheets of plastic to provide a durable outer shell with a hollow interior. In some embodiments, the face panel is moveable by virtue of an integral living hinge that connects the face panel to a generally stationary support panel.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part application of application Ser. No. 10/375,829, filed Feb. 26, 2003, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The subject invention generally pertains to loading dock shelters and more specifically to a side or head shield for such a shelter. 
     2. Description of Related Art 
     Trucks and other vehicles typically back up against a loading dock or doorway of a building to facilitate loading and unloading of the vehicle&#39;s cargo. Often a dock shelter is installed around the doorway to help shelter the area between the perimeter of the doorway and the rear of the vehicle. If left unsheltered, air gaps between the outer wall of the building and the back of the vehicle might allow the outside weather to increase the building&#39;s heating or cooling load, allow rain and snow to enter the interior of the building, or simply subject the inside dock workers to an uncomfortable draft while they service the vehicle. 
     Dock shelters usually include a framework that extends one to three feet outward from the face of the building wall. In some cases, pliable curtains hang from the framework and are situated to drape over the top and either side of a vehicle parked under the shelter. Such curtains are generally not self-supporting and tend to be rather limp, which can create a poor appearance. Although, functionally, such shelters may be adequate in milder climates, additional or alternate sealing may be required where weather conditions are more severe or where tighter control of environmental conditions is required. 
     Thus, some loading docks are provided with dock seals made of resiliently compressible foam pads. As a truck backs its trailer into the dock and against the seal, the foam pads conform to the contour of the rear edges of the trailer. Although such seals provide a very effective seal, they do have a few drawbacks when compared to dock shelters. Foam dock seals are typically more expensive than dock shelters. Seals also reduce the access opening into the trailer because the foam pads overlap the perimeter of the trailer&#39;s opening. Moreover, a foam pad usually needs a tough outer cover to protect the pad from wear and to prevent the pad from absorbing water and dirt. A cover should be tough to resist wear yet pliable to allow compression of the foam. Unfortunately, some of the toughest cover materials are not very pliable, and vise versa. So, a compromise is often needed in selecting a cover with an optimum combination of toughness and pliability. 
     Consequently, a need exists for a dock shelter that provides a more positive seal than current shelters, yet is more economical than conventional dock seals. 
     SUMMARY OF THE INVENTION 
     A dock shelter is provided with a face panel that is relatively lightweight and firm, yet moveable for sealing against vehicles of various size and position. The face panel can be used as a side curtain or a head curtain. To provide the face panel with durability while minimizing its weight, the face panel includes a rather stiff and durable outer shell with a hollow interior. In some embodiments, the face panel is moveable by virtue of an integral living hinge that connects the face panel to a generally stationary support panel. 
     In some embodiments, the outer shell of the face panel comprises two half-shells that are fused to each other. 
     In some embodiments, the two half-shells provide both the face panel and the support panel. 
     In some embodiments, both the face panel and the support panel are hollow. 
     In some embodiments, the living hinge between the face panel and support panel is corrugated for greater flexibility. 
     In some embodiments, a torsion spring urges the face panel to an extended position. 
     In some embodiments, a pliable elongated member limits the pivotal extension of the face panel. 
     In some embodiments, the face panel includes a flexible extension plate that helps protect the main body of the face panel from wear. 
     In some embodiments, the hollow face panel includes recessed areas that enhance the face panel&#39;s rigidity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of one embodiment of a dock shelter. 
         FIG. 2  is a cross-sectional top view taken along line  2 — 2  of FIG.  1  and shows a vehicle backing into the dock shelter. 
         FIG. 3  is the same as  FIG. 2 , but with the vehicle having already backed into the dock shelter. 
         FIG. 4  is a cross-sectional top view taken along line  4 — 4  of FIG.  1 . 
         FIG. 5  is a perspective view showing the upper portion of an integrally formed face panel and support panel, wherein some hardware is removed to illustrate various features of the panels. 
         FIG. 6  is a cross-sectional top view similar to  FIG. 4  but of another embodiment. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1-3 , a dock shelter  10  installed around a doorway  12  of a loading dock  14  includes two face panels  16  and  18  that help provide a weather seal between the rear sides of a vehicle  20  and a wall  22  of a building. To help seal along a rear upper surface of vehicle  20 , another face panel  24  (similar to panels  16  and  18  or of another design, such as a conventional curtain or a compressible foam pad) can be installed along an upper portion of dock shelter  10 . To seal a gap that might exist between upper face panel  24  and the two lateral panels  16  and  18 , a curtain  26  can be used to overlap adjacent panels. 
     Face panels  16  and  18  are coupled to wall  22  by way of two support panels  28  and  30  or by way of some other supporting structure. To allow the face panels to move in response to vehicle  20  backing into dock shelter  10 , face panels  16  and  18  are pivotally connected to support panels  28  and  30 , respectively. Vehicle  20  traveling from its position of  FIG. 2  to that of  FIG. 3  pivots face panels  16  and  18  towards wall  22 . As the face panels pivot, they engage the sides of vehicle  20  to help provide a shelter around vehicle  20 . The actual structure of dock shelter  10 , according to a preferred embodiment, will be described with reference to face panel  16 ; however, the same construction may be applied to face panels  18  and/or  24 . 
     Referring to  FIGS. 4 and 5 , face panel  16  comprises an outside casing member  32  and an inside casing member  34  that are joined, and preferably fused (e.g., melted), to each other along their perimeter  36 . The term, “fused” refers to a joint wherein separation of the joint would involve severing the base material of one or both of the joined items. However, members  32  and  34  can also be joined in a variety of other ways or by using various fasteners including, but not limited to, screws, snaps, adhesive, clips, etc. 
     To create a face panel that is generally rigid yet lightweight, casing members  32  and  34  are thermoformed to provide a generally stiff outer shell with a hollow interior (a hollow chamber  38 ). A twin-sheet thermoforming process, as well known to those skilled in the art, involves expanding two heat-softened thermoplastic sheets (e.g., ⅛-inch thick polyethylene) into two opposing mold cavities by applying an absolute pressure differential between an interior and exterior of the two sheets. The interior or area between the two sheets can be pressurized and/or the exterior of the sheets can be exposed to a vacuum. In some cases, such a process can be applied separately to face panel  16  and support panel  28 , which are later connected to each other by a hinge. In a preferred embodiment; however, panels  16  and  28  are thermoformed in a single operation with an integral living hinge  40  formed where panels  16  and  28  meet. 
     More specifically, outside casing member  32  runs continuously as a unitary sheet across a front face of panel  16  and along one side of support panel  28 . Likewise, inside casing member  34  runs continuously as a unitary sheet across a back face of panel  16  and along another side of support panel  28 . The two casing members  32  and  34  are not only joined to each other along their perimeter but are also joined at several other locations to provide various useful features. 
     For example, to increase the rigidity of panels  16  and  28 , casing members  32  and  34  include several recessed areas  42  and  44  where the inner surfaces of members  32  and  34  come together. Also, recessed areas  46  and  48  facilitate the mounting of various hardware items, such as a torsion spring  50 , leaf spring  52 , and an extension plate  54 , all of which will be explained further. 
     While living hinge  40  allows face panel  16  to pivot relative to support panel  28 , torsion spring  50  (or some other type of resilient member) interacts with panels  16  and  28  to urge face panel  16  to pivot away from support panel  28  and toward vehicle  20 . To limit the angular travel of face panel  16  and establish a predetermined angle  56  between panels  16  and  28  (e.g., 90-degrees, as shown) when a vehicle is not presently at loading dock  14 , a fabric strap  58  (or some other pliable elongated member, e.g., chain, cable, rope, etc.) attaches between panels  16  and  28 . Spring  50  and strap  58  can be mounted in various ways; however, in some embodiments, opposite ends of spring  50  are held to panels  16  and  28  by way of clamp plates  60  and fasteners  62  (e.g., screws, bolts, rivets, etc.). 
     Since hollow chamber  38  helps make face panel  16  rather rigid, the more flexible extension plate  54  (e.g., ¼-inch thick polyethylene) can be fastened to it. Extension plate  54  not only provides face panel  16  with a distal edge  64  that is more adapted to seal against vehicle  20 , but plate  54  also helps protect against wear of other portions of face panel  16  from wear. Distal edge  64  is preferably curved about a vertical axis to avoid having edge  64  catch against the side of vehicle  20  as vehicle departs loading dock  14 . 
     Although edge  64  is shown curved toward the face of wall  22 , in some embodiments, the edge can curve in an opposite direction, away from wall  22 . In  FIG. 6 , for example, a dock shelter  10 ′ includes a distal edge  64 ′ that curves away from wall  22 . This allows the rear vertical edge of a truck&#39;s trailer to fit inside the inner surface of the curved distal edge, whereby the curved distal edge  64 ′ helps seal a gap along the trailer&#39;s rear door hinges. 
     To provide extension plate  54  with additional resilience or spring-back, one or more leaf springs  52  can be installed between plate  54  and the front face panel  16 . Fasteners  66  (e.g., rivets, screws, bolts, etc.) can be used to attach plate  54  and spring  52  to face panel  16 . Recessed areas  48  that place interior surfaces of casing members  32  and  34  against each other allow fasteners  66  to tightly clamp extension plate  54  and spring  52  against face panel  16  without adversely crushing panel  16 . 
     To adapt support panel  28  for mounting to wall  22 , panel  28  is provided with several cavities  68  and  70 , which allow fasteners  72  to be inserted through holes  74  and anchored to wall  22 . Cavities  68  and  70  are alternately formed in casing members  32  and  34 , respectively. Such an alternate arrangement provides support panel  28  with greater strength and resistance to forces that may urge panel  28  to bend about its mounting surface  76 . 
     To enhance the ability of face panel  16  to pivot relative to support panel  28 , casing member  32  and/or  34  are corrugated in the area of hinge  40 . As face panel  16  pivots through it full range of motion, the corrugations reduce localized strain in the base material of members  32  and  34  by distributing the bending action over the circumference of hinge  40 . The reduced strain increases the fatigue life of hinge  40 . 
     Although the invention is described with reference to a presently preferred embodiment, it should be appreciated by those skilled in the art that various modifications are well within the scope of the invention. Therefore, the scope of the invention is to be determined by reference to the claims that follow.