Abstract:
A tonneau cover for a truck bed is provided with an inner panel and an outer panel. A plurality of five pointed star shaped indentations are formed on the inner panel. Each indentation includes ten angularly oriented sidewalls that extend from the inner panel and converge towards an upper land. Each upper land is attached to the outer panel at spaced apart intervals and provides reinforcement in ten different directional planes along the ten sidewalls.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation-in-part of U.S. application Ser. No. 29/357,437 filed on Mar. 12, 2010, the entire disclosure of which is incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    This disclosure relates to truck bed covers that are rigid and that include an outer top panel and reinforcing inner lower panel. 
       BACKGROUND 
       [0003]    Trucks, such as pick-up trucks, may have an open bed that is enclosed on the front and opposite lateral sides by walls. A tailgate is normally provided to selectively close the back end. The top of the bed area is normally open. 
         [0004]    Tonneaus are provided to cover the top of the bed. Tonneaus may be soft, or fabric, covers that are snapped or clipped to the top edge of the front wall, the side walls and the tailgate. Rigid tonneaus are also available that span the top of the truck bed area. Rigid tonneaus may be made of fiberglass, injection molded thermoplastic, TPO, SMC, or thermal formed thermoset plastic sheets. Rigid plastic tonneaus generally include ultraviolet protection additives in at least the top panel. Generally, an outer top panel is attached to an inner lower panel that reinforces the top panel. Sufficient reinforcement must be provided to prevent vibration when the truck is moving or buckling when objects are placed on the tonneau. 
         [0005]    Rigid tonneau panels are generally considered to be the preferred option for durability and appearance. However, the principal drawbacks are the weight of the tonneau and the manufacturing cost. The weight of the tonneau adds to the effort required to lift the tonneau and also adversely impacts fuel economy. Tonneaus made of thermal formed thermoset plastic sheets that are drawn to shape may have linear ribs formed in the inner panel. Excessive thinning may occur in the vertical walls of linear ribs that necessitate the use of selecting thicker sheets to avoid splits and insufficient reinforcement strength properties. 
         [0006]    There is currently a need to provide a strong and light weight tonneau cover for a truck bed and a method of making the inner panel of the tonneau that requires less material and, as a result, is less expensive. There is also a need to provide a method of making a tonneau that results in substantial energy savings and reduces the energy required to heat and form the panels. In addition, there is a need to use thinner panels for the inner reinforcing panel that reduces the overall weight of the assembly and reduces vehicle fuel consumption. 
       SUMMARY 
       [0007]    A tonneau cover for a truck bed is disclosed that includes a plurality of indentations on an inner panel that converge from the inner panel toward an outer panel and that provide stable support for the outer panel. 
         [0008]    According to one aspect of the present invention, a tonneau is provided that includes an inner panel that provides support for an outer panel that is spaced apart from the inner panel. The outer panel has an upper wall that is bounded by a front edge, a rear edge and two side edges. The inner panel has a lower wall that is provided with a plurality of indentations. Each of the indentations may be in the shape of a five pointed star. Ten sidewalls in each indentation converge toward an upper land, and the upper lands are attached to the upper wall to provide reinforcement in ten different directional planes. As an alternative, the indentations may be in the shape of a frustum of a five pointed star pyramid. 
         [0009]    According to another aspect of the invention, a tonneau is provided that includes a lower wall of an inner panel provided with a plurality of indentations in the shape of a frustum of a regular polygonal pyramid. The regular polygon has N sides, where N is greater than four. Sidewalls extend from each of the N sides towards an upper wall and are oriented at an angle of between 30 and 60 degrees relative to the lower panel. The sidewalls converge to form an upper land that is in the shape of the polygon. The upper lands are connected to the upper wall and provide reinforcement in N different directional planes along the N sidewalls. 
         [0010]    In yet another aspect of the invention, a tonneau includes an outer panel with an upper wall and an inner panel with a lower wall. The lower wall is provided with a plurality of indentations that are each in the shape of a frustum of a cone. A side wall of the indentation extends radially outwardly from an upper land to the inner panel. The upper lands may be connected to the outer panel so that the sidewalls provide reinforcement in all radial directions about the upper land. 
         [0011]    These and other aspects of the invention will be better understood in view of the attached drawings and the following detailed description of the illustrated embodiments on the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a rear perspective view of a pick-up truck having a tonneau having discrete star shaped reinforcing members that is made according to one embodiment of the present disclosure; 
           [0013]      FIG. 2  is a bottom plan view of the inner panel of the tonneau of  FIG. 1 ; 
           [0014]      FIG. 3  is a cross-sectional view taken along the line  3 - 3  in  FIG. 2 ; 
           [0015]      FIG. 4  is a bottom plan view of an inner panel of an alternative embodiment of a tonneau having discrete hexagonal shaped reinforcing members; 
           [0016]      FIG. 5  is a cross-sectional view taken along the line  5 - 5  in  FIG. 4 ; 
           [0017]      FIG. 6  is a cross-sectional view taken along the line  6 - 6  in  FIG. 4  illustrating an alternate embodiment of the hexagonal shaped reinforcing members of  FIG. 5 ; 
           [0018]      FIG. 7  is a bottom plan view of an inner panel of an alternative embodiment of a tonneau having discrete circular shaped reinforcing members; and 
           [0019]      FIG. 8  is a cross-sectional view taken along the line  8 - 8  in  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Detailed embodiments of the present invention are disclosed, but it should be understood that the disclosed embodiments may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. Specific structural and functional details disclosed by Applicant are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art how to practice the present disclosure. 
         [0021]    Referring to  FIG. 1 , a pick-up truck  10  is shown with a tonneau  12  made according to one embodiment of the disclosure. The tonneau has an outer panel  14  and an inner panel  16  that are connected together in a layered arrangement. The outer panel  14  and the inner panel  16  are formed from ABS plastic sheets in a thermal forming operation. The ABS sheets are heated and then formed against a one-sided die that draws the sheets against the die. A plurality of discrete reinforcements  18  that are in the shape of a five pointed star are formed in the inner panel  16 . The reinforcements  18  are also attached to the outer panel  14  to reinforce the outer panel  14 . 
         [0022]    Referring to  FIG. 2 , the inner panel  16  is shown in greater detail. The inner panel  16  is shown from the bottom in  FIG. 2 . The inner panel  16  has a base wall  20  in which the reinforcements  18  are formed. The reinforcements  18  have a plurality of convergent sidewalls  22  that converge as they approach the outer panel  14 . An upper land  24  is provided at the upper end of the sidewalls  22 . The upper land  24  is star shaped. The reinforcement  18  in this embodiment is in the shape of a 5-point star. It should be understood that the star shape may have three or more points. Star shaped reinforcements  18  may be oriented and positioned as to be in a “clocked” arrangement so that the points of the stars are partially received within the valleys of surrounding stars. A clocked arrangement allows more reinforcements  18  to be formed on the base wall  20  to provide increased support. 
         [0023]      FIG. 3  is a cross-section is taken along the line  3 - 3  in  FIG. 2  that illustrates the relationship of the outer panel  14  and the inner panel  16 . The upper land  24  is attached to the outer panel  14  by an adhesive, sonic welding, solvent welding, or by another plastic attachment technique. The sidewalls  22  extend upwardly from the base wall  20  (directional references as used herein are to the tonneau when installed on a pick-up truck in the closed position) and converge as they approach the outer panel  14 . 
         [0024]    In the embodiment of  FIGS. 1-3 , the sidewalls are oriented at about 45 degrees relative to the base wall with the angular orientation being represented by the letter “A.” The angular orientation may range from 30 to 60 degrees provided that the wall thickness is not thinned during forming and provides sufficient reinforcement. As angle A of the sidewall  22  increases above about 45 degrees the thickness of the sheet in the area of the sidewall  22  tends to thin out during forming operations, but between 30 and 60 degrees the sheet does not thin out to any substantial extent. If the sidewall is oriented at less than 30 degrees the sidewalls, less reinforcement is provided to the outer panel  14 . 
         [0025]    In the embodiment of  FIGS. 1-3 , while the reinforcements  18  are illustrated as a frustum of a star pyramid, it should be understood that each reinforcement  18  may be in the shape of a star that is not a frustum of a pyramid. Each star shaped reinforcement has ten sidewalls that reinforce the structure in ten different directions. Each of the sidewalls  22  is supported by adjacent sidewalls  22  that are not parallel to the upper and lower edge intersections with the outer panel  14  and inner panel  16 . The upper edge intersection of the sidewall  22  with the outer panel  14  is substantially shorter than the lower edge intersection of the sidewall  22  with the inner panel  16 . The intersecting sidewalls  22  and panels  14  and  16  provide a self-supporting framework that is similar to a geodesic dome. The angles connecting the wall to outer panel  14  and inner panel  16  would normally permit compression in that direction. However, other nine directions of reinforcement prevent compression of the assembly. Each reinforcement element is independent from the other reinforcements. This embodiment is of a five pointed star but it should be understood that a star having three points, four points, six points or more points can be provided that offer similar beneficial reinforcement performance. 
         [0026]    Each reinforcement  18  has a star shaped recess in its base wall  20  and tapers to a geometrically-similar star shape on its upper land  24  The sidewalls define a frustum of a star pyramid. Forces applied to the outer panel  14  are transferred in an angular direction through the sidewalls  22  to the base wall  20 . Each five pointed star has ten sidewalls  22  that extend between the outer panel  14  and the inner panel  16 . Each of the ten sidewalls  22  provides a differently oriented edge that resists compression of the space between the outer panel  14  and the inner panel  16 . Each of the sidewalls  22  is joined to two laterally adjacent sidewalls  22  by an inner corner  26  and an outer corner  28 . The two sidewalls  22  of each point extend from a pair of inner corners  26  to an outer corner  28 . The two sidewalls  22  form a V-shaped spine that is cantilevered between the outer panel  14  and the inner panel  16 . The spine extends from upper land  24  to the base wall  20  between each pair of intersecting sidewalls  22  of each reinforcement  18 . The intersecting sidewalls  22  and corners  26 ,  28  create a strong reinforcement between the outer and inner panels  14  and  16 . 
         [0027]    Referring to  FIG. 4 , another embodiment is provided in which a plurality of discrete polygonal reinforcements  34  are formed in the inner panel  16 . A hexagonal reinforcement is illustrated in  FIG. 4  but it should be understood that the discrete polygonal reinforcement  34  preferably has five or more sides. 
         [0028]    Referring to  FIG. 5 , a cross-section is taken along the line  5 - 5  in  FIG. 4  to show the relationship of the outer panel  42  to the inner panel  16 . The sidewalls  38  extend upwardly from the base wall  36  and converge as they approach the outer panel  42 . The sidewalls  38  are oriented at about 45 degrees relative to the base wall with the angular orientation being represented by the letter “A.” The angular orientation may range from 30 to 60 degrees as previously explained with reference to  FIGS. 2 and 3  above. 
         [0029]    Referring to  FIG. 6 , a cross-section is taken along the line  6 - 6  in  FIG. 4  to show an alternate embodiment of the polygonal reinforcements  34 . A fillet  44  connects the sidewalls  38  to the upper land  40 , and a radially curved portion  46  connects the sidewalls  38  to the base wall  36 . While this embodiment is illustrated with reference to a polygonal reinforcement  34 , it should be understood that a fillet  44  and a radially curved portion  46  can be applied to a star shaped reinforcement  18 , a frustoconical reinforcement  48 , or any other shaped reinforcement. 
         [0030]    With respect to  FIGS. 4-6 , each reinforcement  34  has a polygonal indentation in the base wall  36  with the convergent sidewalls  38  extending to the upper land  40  that is a geometrically-similar polygonal shape. The convergent sidewalls  38  define a frustum of a polygonal pyramid. Forces applied to the outer panel  42  are transferred in an angular direction through the sidewalls  38  to the base wall  36 . The angular distribution of force through the frustum of the star pyramid in the embodiment of  FIGS. 1-3  and through the frustum of the polygonal pyramid in the embodiment of  FIGS. 4-6  provides a strong and durable tonneau  12 . While reinforcements  34  are illustrated as a frustum of a polygonal pyramid, it should be understood that each reinforcement  34  may be in the shape of a polygon that is not a frustum of a pyramid. 
         [0031]    Referring to  FIGS. 7 and 8 , another embodiment is illustrated that includes a plurality of discrete frustoconical reinforcements  48 . A circular recess is formed in the base wall  50  and a frustoconical side wall  52  (the term frustoconical as used herein refers to a frustum of a cone) extends and converges in the direction towards the outer panel  56 . A circular upper land  54  is disposed at the upper end of the frustoconical sidewall  52  that is attached to the outer panel  56 , as previously described with reference to the embodiments illustrated in  FIGS. 1-6 . 
         [0032]    While the embodiment of  FIGS. 6 and 7  does not have planar sides that extend in a plurality of lateral directions, a force applied in one direction is resisted by the balance of the perimeter of the side wall  52 . 
         [0033]    While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosure. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.