Patent Publication Number: US-2006008609-A1

Title: Sandwich panel and method of manufacturing same

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application claims the benefit of U.S. Provisional Application No. 60/539,517 filed Jan. 26, 2004, the entire contents of which are herein incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a sandwich panel and method of manufacturing a sandwich panel and, more particularly, to a sandwich panel and method of manufacturing a sandwich panel for use as a structural member.  
      2. Description of the Related Art  
      Load panels are used for covering storage areas and supporting weight in applications such as automotive interiors and storage spaces. Common uses include load floors, bay covers, flipper panels, seat backs, and cargo cabinets. Solid material panels are used for typical load panels in addition to blow molded panels.  
      A known prior art load panel is shown in  FIGS. 1 and 2 .  FIG. 1  illustrates a typical single layer structural panel  20  in a closed position. Such a structural panel is integrated with an automobile floor  22  or side panel of an automobile. In the closed position, structural panel  20  is received by a support space  24 . Structural panel  20  may be held in place by hinges  26 ,  28  and latches  30 ,  32 . Latches  30 ,  32  may unlock structural panel  20  from support space  24 . After unlocking, structural panel  20  may be opened to expose a cavity  33  defined by support space  24 .  FIG. 1  illustrates a system using latches  30 ,  32  and hinges  26 ,  28 .  FIG. 2  illustrates a typical structural panel  20  in an open position. Panel  20  has been folded back to expose support space  24  and cavity  33 .  
      However, typical load panels have undue flex when supporting large weights. Additionally, typical panels do not maintain their desired shape under changes in atmospheric conditions such as temperature and humidity. The typical solid or single layer panels do not have the rigidity or atmospheric stability required for the harsh automotive environment. Additionally, typical panels do not include finished edges or edges that trap covering material at the edges to reduce peeling or separation of covering material.  
      Accordingly, a panel and method of manufacturing a panel is required that has improved strength, stiffness, dimensionally stability under various atmospheric conditions, provides expanded covering solutions, reduces costs for attachment devices installed during manufacture, and provides the option of trapping carpet fibers used as covering. More particularly, a panel is needed that provides for an improved panel for use as a structural member in, among other applications, automotive interior components, such as cargo trays, load floors, bay covers, flipper panels, seat backs, cargo cabinets and the like.  
     BRIEF SUMMARY OF THE INVENTION  
      The present invention provides a structural panel and a method of manufacturing a structural panel. An embodiment comprises two skins attached to each other forming a structural panel. Another embodiment comprises two skins attached to an intermediate substrate forming a structural panel. Each skin may be made of a pressboard material. The skins may be attached to the intermediate substrate using adhesives or other attachment methods. Further, a covering material may be selectively applied to the skins.  
      Another embodiment comprises two skins attached to an intermediate substrate forming a structural panel further including an edge member. The edge member may include an engaging member that mechanically engages the intermediate substrate. The engaging member may also have anti-reverse fins that prevent the engaging member from backing out of the intermediate substrate. Further, a covering material may be selectively applied to the skins for improved reliability or for cosmetic appearance. The edge member may also trap a portion of the covering material to improve reliability and improve fit and finish of the panel.  
      The present invention also provides a method for manufacturing the sandwich panel for an automobile where two skins of predetermined size and shape are provided and attached to each other forming a structural panel. An intermediate substrate may also be provided and attached between the skins. The skins and intermediate substrate may be attached using adhesives or other fasteners. Further, additional hardware such as handles, connectors or the like, may be installed onto the panel. Another method of manufacturing the sandwich panel includes an edge member applied to the periphery of the structural panel. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein:  
       FIG. 1  is a perspective view of a general representation of a generic conventional structural panel in a closed position;  
       FIG. 2  is a perspective view of a general representation of a generic conventional structural panel in an open position;  
       FIG. 3  is a cross sectional view of a two layer sandwich panel according to an embodiment of the present invention;  
       FIG. 4  is a cross sectional view of a multilayer sandwich panel according to an embodiment of the present invention;  
       FIG. 5  is a cross sectional view of a multilayer sandwich panel including edging according to an embodiment of the present invention;  
       FIG. 6  is a deflection graph comparing a sandwich panel according to an embodiment of the present invention to a prior art panel; 
    
    
     DETAILED DESCRIPTION  
      Referring now to the drawings, the preferred illustrative embodiments of the present invention are shown in detail. Although the drawings represent some preferred embodiments of the present invention, the drawings are not necessarily to scale and certain features may be exaggerated to better illustrate and explain the present invention. Further, the embodiments set forth herein are not intended to be exhaustive or otherwise limit or restrict the invention to the precise forms and configurations shown in the drawings and disclosed in the following detailed description.  
       FIG. 3  illustrates a cross sectional view of a two layer sandwich panel  34  according to an embodiment of the present invention. Panel  34  includes at least two substrates or skins  42 ,  44 . The skins  42 ,  44  may be fixed to one another using adhesive or other fastening methods. The sandwich of skins  42 ,  44  improves the strength, stiffness, and dimensional stability of the panel over various atmospheric conditions. The shape of each skin  42 ,  44  is defined by a peripheral edge  46  sized or otherwise configured to fit within or mate with an intended support space  24  (as shown in  FIG. 2 ). Skins  42 ,  44  may be made of a pressboard-like material, such as “SUPERWOOD®,” (a registered trademark of Georgia Pacific Corporation), which is a type of hardboard. However, other materials, such as plastics, may also be employed in skins  42 ,  44 .  
       FIG. 4  illustrates a cross sectional view of a multilayer sandwich panel  36  according to an embodiment of the present invention. Sandwich panel  36  has a third substrate or center layer  48  disposed between two outer skins  42 ,  44 . The addition of center layer  48  provides additional structural integrity to sandwich panel  36 . Center layer  48  may be made of any one or combination of wood, cardboard, plastic, metal, expanded or non expanded foam, and other structural materials. The skins  42 ,  44  may be fixed to center layer  48  using adhesive or other fastening methods. One or more additional intermediate layers may be added to the illustrated panel without departing from the scope of the invention.  
       FIG. 5  illustrates a cross sectional view of a multilayer sandwich panel  40 . Panel  40  includes at least three layers; a first outer skin  42 , a center layer  48 , and a second outer skin  44 . Skins  42 ,  44  are secured to the center layer  48  using adhesives or other fastening methods. One or more additional intermediate layers may be added to the panel without departing from the scope of the invention.  
      When panel  40  is received in an automotive interior, for example, skins  42 ,  44  may be formed to match not only the peripheral shape of the area into which panel  40  may be received, but also the contour thereof. The contours may include a complex shape of an interior wall, or, for example, a bulge, pocket, or recess in an otherwise flat panel. Because skins  42 ,  44  may be made of a pressboard-type material, such as SUPERWOOD®, panel  40  may be molded in a heated press to conform to the shape of the receiving environment or to provide additional structural rigidity through predetermined structural formations, such as folds, bends and pockets. Among other benefits, panel  40  is dimensionally stable under various atmospheric conditions.  
      Panel  40  may also be aesthetically configured to provide an attractive outward appearance to complement the décor of the automobile interior. For example, skins  42 ,  44  may be covered with an upholstery material or painted to match the décor of a vehicle interior. Panel  40  allows for unique covering solutions, particularly when compared to similar non-sandwich products. Depending upon predetermined design considerations, one or both sides of panel  40  may be covered with a covering material  50 , such as upholstery, carpet, leather, rubber or the like. If applied, covering material  50  then forms an exterior surface  52  of panel  40 .  
      As illustrated in  FIG. 5 , an edge member  54  may be applied around at least a portion of the edges of panel  40 . Edge member  54  may be applied to the entire periphery of panel  40 , or edge member  54  may be applied only to a portion of the edges of panel  40 . As edge member  54  forms to shape of the peripheral edge  46 , panel  40  and outer peripheral edge  56  must be configured appropriately to be received by the intended support space. The thickness and cross-sectional profile of edge member  54  may be varied to tailor the edge strength of the panel, facilitate alignment of the panel with mating components in a vehicle, and serve as an anchor to interface with attachment hardware in the vehicle.  
      In the embodiment shown in  FIG. 5 , panel  40  incorporates an edge member  54  applied to the edges of the panel  40  (similar to the finishing on a table or desk edge). The edge member  54  generally provides a durable outer peripheral edge  56  that reduces warranty costs to the OEM and the manufacturer for damaged panels because, among other things, the edge member  54  protects the panel  40  from damaged during use. Edge member  54  may also provide a more refined appearance to the load panel and may be configured to match the interior or trim pieces of the vehicle.  
      In a particular implementation, edge member  54  includes an extruded plastic or vinyl cap having an engaging member  57  with anti-reverse fins  58 . Fins  58  extend outwardly from engaging member  57  to grip center layer  48 . Fins  58  may be configured to allow for easy insertion of the engaging member  57  with center layer  48 , and may also be configured to prevent extraction of engaging member  57  from center layer  48  once installed. Once engaged in panel  40 , fins  58  prevent the edge member  54  from releasing from the engaging substrate. Thus, anti-reverse fins  58  firmly hold edge member  54  to the panel  40 . Other ways of securing edge member  54  to panel  40 , such as adhering edge member  54  to panel  40 , are also within the scope of the invention.  
      Edge member  54  may also include edge(s)  60  that trap covering material  50  and allow the panel to meet or exceed standards for fit, finish and safety, among other things. Among other benefits, edge member  54  allows for a professionally finished edge with less labor and/or material than typical pinch trimmed or edge folded panels. Edge member  54  may also trap the covering material  50  under its edge preventing the covering material  50  from delaminating from the skin(s)  42 ,  44 .  
      Panel  40  may also be fitted with various devices such as handles, connectors or the like, which may be used with the panel  40  in its installed environment. The devices may be secured or attached to panel  40  in a number of ways, including, without limitation, adhering, screwing, riveting, and using an engaging member with anti-reverse fins  58  similar to that shown in  FIG. 5 . With the disclosed panel design, latch and hinge installation improvements for weight and cost savings are practical.  
       FIG. 6  illustrates a deflection graph comparing a sandwich panel according to an embodiment of the present invention to a prior art panel. In one particular implementation of the invention, panel  40  is used as a load-floor in the interior of an automobile. Such load-floors may be used to cover a spare tire in the vehicle or as a door to a storage compartment. In a particular load-floor application, the deflection of a load-floor employing panel  40  of the present invention was compared to a prior art automotive load-floor at 25° C. and 82° C. The prior art load-floor exhibited a greater deflection for a given load than did the load-floor employing panel  40  at both 25° C. and 82° C.  
      It will be appreciated that panel  40  is not limited to use as a load-floor in a vehicle. Among other applications, panel  40  may be used in a number of automotive interior components, such as cargo trays, load floors, bay covers, flipper panels, seat backs, cargo cabinets or the like. Further, panel  40  may be used in a number of non-automotive applications, particularly where a recyclable, formable structural member is desired.  
      A method for manufacturing panels according to embodiments of the present invention will now be described. Skins  42 ,  44  are cut to the appropriate dimension and, optionally, molded or formed under heat and/or pressure to create the desired shape of the panel. The optional intermediate substrate or center layer  48  is secured between skins  42 ,  44  prior to or after the covering material  50  is applied to skins  42 ,  44  (if required). An edge member  54  may then be secured to the panel by engaging anti-reverse fins  58  with the panel or adhering the edge member to the panel. If required, additional hardware, such as handles, connectors or the like, may be installed onto the panel.  
      The present invention has been particularly shown and described with reference to the foregoing embodiments, which are merely illustrative of the best modes for carrying out the invention. It should be understood by those skilled in the art that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention without departing from the spirit and scope of the invention as defined in the following claims. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the invention should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing embodiments are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.