Abstract:
A vehicle hood assembly is provided with a pair of fender panels that attach to a central panel at a first attachment point and a second attachment point. The fender panel is L-shaped in cross-section between the first attachment point and the second attachment point such that it functions as an air management channel. The central panel and the fender panels are preferably injection molded parts. The present invention also includes a method for manufacturing a vehicle hood.

Description:
BACKGROUND OF THE INVENTION 
   The present invention is related to vehicle hood assemblies, and more particularly to a structurally improved vehicle hood assembly. 
   Vehicle hood assemblies, especially those for trucks and other heavy duty vehicles, are generally comprised of sheet molding compound (“SMC”). These hoods may be comprised of a single piece, but are often comprised of multiple pieces, such as separate fender panels attached to a central hood panel. For example,  FIG. 1  shows a multiple panel hood  10  having a generally horizontal hood panel  12 , and a pair of fender panels  14  attached on either side of the hood panel  12 . 
   As shown in  FIG. 2 , fender panels  140  are commonly attached to the hood panel  120  with a small overlap  130  (approximately 2″) and a conventional bond, such as a two part adhesive. This conventional attachment provides an aesthetically pleasing seam  130  between the hood and the fender. Unfortunately, the conventional assembly is difficult to separate for replacement of a panel, and the bonding fixtures and adhesive can be expensive. 
   As shown in  FIG. 5 , it also is known to attach SMC pieces  150  to the underside of the hood to add structural stability to the hood and to define a channel for directing air to a plenum for intake air and/or HVAC air. The structural members and air channel are functional, but they add material and labor cost to the hood assembly. 
   Although these vehicle hoods are currently considered adequate by those skilled in the art, artisans continue to seek advancements in appearance, structure, and ease of manufacturing and serviceability. 
   SUMMARY OF THE INVENTION 
   The aforementioned problems are overcome by the present invention wherein a vehicle hood assembly is provided with a pair of fender panels that 1) provide increased structural support; 2) increase the ease of manufacture, and 3) provide integral air channels. 
   In a preferred embodiment, each fender panel attaches to the hood panel at a first attachment point and a second attachment point. Instead of the conventional small overlap at the attachment point, the fender panels of the present invention attach at a first point inwards of the lateral edge of the hood panel, and at a second point near the lateral edge of the hood panel. The multiple attachment points and resulting extra material in the fender panel between the attachment points increases the strength of the hood, and reduces the need for additional structural members. 
   In a more preferred embodiment, the fender panel is L-shaped in the section between the first attachment point and the second attachment point, forming a box shaped cross section between the hood panel and the fender panel. In another preferred embodiment, the L-shaped section of the fender panel is stepped in a number of locations. The steps further increase the structural strength of the vehicle hood. An additional result of this L-shaped section is that it forms a chamber between the fender panel and the hood panel that functions to channel outside air. 
   It is also preferable that the hood panel and the fender panels are injection molded plastic. The panels are separately molded into the desired shape, and then removably attached together at the attachment points. The use of plastic increases the ease of manufacture, and creates a much lighter vehicle hood, without reducing the structural integrity of the vehicle hood. The preferred attachment increases the ease of serviceability of a single panel. 
   The present invention also includes a method for manufacturing a vehicle hood, comprising the steps of: a) injection molding a hood panel that includes a central portion and lateral portions; b) injection molding a pair of fender panels, each fender panel having a first, L-shaped section adapted to attach to the hood panel and a second section extending from the first section; and then c) attaching the fender panels to opposing sides of the hood panel at a first location in the central portion, and a second location in the lateral portion, forming a chamber between the hood panel and the fender panel between the first and second attachment locations. 
   These and other objects, advantages, and features of the invention will be more fully understood and appreciated by reference to the detailed description of the preferred embodiment and the drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a truck hood. 
       FIG. 2  is a sectional view of the prior art panel attachment taken along line  2 - 2  in  FIG. 1 . 
       FIG. 3  is a sectional view of the prior art including a structural member taken along line  3 - 3  in  FIG. 1 . 
       FIG. 4  is a sectional view of the preferred embodiment present invention taken along line  2 - 2  in  FIG. 1 . 
       FIG. 5  is a sectional view of an alternative embodiment of the present invention taken along line  2 - 2  of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A vehicle hood in accordance with the preferred embodiment of the present invention is shown in  FIG. 1  and generally designated  10 . The vehicle hood  10  includes an injection molded hood panel  12 , and a pair of injection molded fender panels  14  on opposing sides of the hood panel  12 . The hood panel  12  includes a central portion  16  and opposing lateral portions  18  that extend downwardly from the central portion  16 . Referring now to  FIG. 4 , the fender panels  14  are each attached to the hood panel  12  at a first attachment location  20  in the central portion  16  and a second attachment location  22  in the lateral portion  18 . A chamber  24  is formed between the hood panel  12  and the fender panels  14  between the first and second attachment locations  20 ,  22 . The vehicle hood is manufactured by injection molding the hood panel  12  and the fender panels  18 , and then attaching the fender panels  18  to opposing sides of the hood panel  12 . 
   The hood panel  12  is preferably molded as a single part from an injection molding grade thermoplastic, and preferably includes a central portion  16  and opposing lateral portions  18 . The central portion  16  is a generally horizontal panel formed to a size and shape that will cover the engine compartment of a desired vehicle having a front edge  50 , and a rear edge  60  (see  FIG. 1 ). The central portion  16  includes an upper surface  26  and a lower surface  28 . Each surface  26 ,  28  may include a variety of aesthetic features, such as designs or indentations, and functional features, such as a handle or a grill attachment (see, for example,  FIG. 1 ). The lateral portions  18  are preferably symmetrical, extending from opposing sides of the central portion  16  and including an inner surface  32  and an outer surface  34 . The sectional view in  FIG. 4  shows one half of this design, the other half preferably being a mirror image of the first. The lateral portions  18  preferably curve downward from the central portion  16  forming a corner  30 . The corner  30  is preferably radiused, so that the outer surface  34  is smooth. The corner  30  preferably forms approximately a 90 degree angle, but the angle may vary depending on the desired shape of the hood  10 . The lateral portions  18  each terminate in a lateral edge  32 . In a preferred embodiment, the terminal portion of each lateral portion  18  corners inward to form a flange  36  for attachment to the fender panels  14 . 
   The fender panels  14  are attached to opposing sides of the hood panel  12 . Like the hood panel  12 , the fender panels  14  are each preferably comprised of a thermoplastic that is injection molded to a desired shape. The fender panels  14  each include an attachment portion  38  and an exterior portion  40  molded as one piece. The attachment portion  38  is preferably L-shaped, including a first vertical member  42  and a second horizontal member  44 . The vertical member  42  preferably includes one or more steps  46  for increasing the strength of the vertical member  42 , and terminates in a flange  48  that extends at an angle from the vertical member  42 . 
   The attachment portion  38  preferably attaches to the hood panel  12  in two locations. The first attachment location  20  is preferably between the flange  48  and the lower surface  28  of the hood panel central portion  16 . This attachment  20 , shown in  FIG. 4 , preferably includes a hook tab  56  for engaging the flange  48 . The hook tab  56  preferably extends downwardly from the lower surface  28  of the hood panel  12 , and runs substantially from the front  58  to the back  60  of the hood panel  12 . In this preferred embodiment, the fender panel  14  is positioned so the flange  48  is fitted into the hook tab  56 . The second attachment location  22  is preferably between the flange  36  and the horizontal member  44 . This attachment preferably includes a conventional bolt  50  that extends through both the flange  36  and the horizontal member  44  into a nut  51 .  FIG. 5  shows an alternative embodiment, wherein the first 20 and second 22 attachments are formed with conventional bonding techniques. 
   When each fender panel  14  is attached to the hood panel  12 , a box-like chamber  24  is formed between the L-shaped attachment portion  38  and the hood panel  12 . The chamber  24  may function as an air management channel. The exterior portion  40  of the fender panel extends downward from the attachment portion  38 , forming an exterior wall of the vehicle. The exterior portion  40  preferably forms at least a portion of a fender, but may be formed to any desired shape. 
   Manufacture of the preferred vehicle hood comprises the steps of a) injection molding a first thermoplastic into a hood panel, including a central portion and opposing lateral portions; b) injection molding a pair of symmetrical fender panels, each having an L-shaped attachment portion and an exterior portion; and c) attaching each of the fender panels to one of the opposing sides of the hood panel at a first location in the central portion of the hood panel and a second location in the lateral portion of the hood panel. 
   The above description is that of a preferred embodiment of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any reference to claim elements in the singular, for example, using the articles “a,” “an,” “the” or “said,” is not to be construed as limiting the element to the singular.