Abstract:
A vehicle shield is provided according to the invention. The vehicle shield is constructed to avoid excessive hood flutter. The shield includes a hood protector region and an attachment region. The hood protector region is constructed for extending across at least a portion of a vehicle hood for protecting the vehicle hood. The attachment region is constructed for attaching the hood protector region to a vehicle. Also provided is a method of installing the shield to a motor vehicle.

Description:
FIELD OF THE INVENTION 
   The invention relates to a vehicle hood shield for mounting to the front end of a vehicle. 
   BACKGROUND OF THE INVENTION 
   Numerous types of vehicle shields have been developed to protect a vehicle from contact with road debris, bugs, and to deflect airflow away from windshields. These devices are also commonly referred to as bug shields or airflow deflectors. Such devices are described in U.S. Pat. No. 4,929,013 to Eke, U.S. Pat. No. 5,112,095 to Lund et al., U.S. Pat. No. 5,755,483 to Lund, U.S. Pat. No. 6,027,156 to Lund et al., and U.S. Pat. No. 6,752,446 to Espinose et al. All of the above patents are assigned to Lund Industries, Incorporated, the assignee of this patent application. 
   Changes in the design and manufacturing of vehicle hoods have raised new issues with respect to the construction of vehicle shields. As compared to older model vehicles, the hoods on later model vehicles are generally thinner and lighter. Attaching standard hood shields to later model vehicles can cause the hoods on the later model vehicles to flutter excessively at high speeds. Accordingly, one object of this invention is to provide a hood shield that does not cause an unacceptable amount of hood flutter when the vehicle is driven at a high rate of speed. 
   SUMMARY OF THE INVENTION 
   A vehicle shield device is provided according to the invention. The vehicle shield includes a hood protector region and an attachment region. The hood protector region is constructed for extending across at least a portion of a vehicle hood for protecting the vehicle hood. The attachment region is constructed for attaching the hood protector region to a vehicle. 
   The hood attachment region includes a first hood attachment flange constructed for attaching to a first side of a vehicle hood, a grille engagement flange constructed to be sandwiched between the hood and the grille, and a second attachment flange constructed for attachment to a second side of a vehicle hood. The hood protector region and the hood attachment region are constructed such that when the vehicle shield is attached to a motor vehicle the hood flutter is minimal even when the vehicle is driven at a high rate of speed. Also provided according to the invention is a method for installing a vehicle shield. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective front view of a vehicle shield according to the principles of the invention provided on a motor vehicle; 
       FIG. 2  is an exploded assembly view of the vehicle shield, vehicle hood, and vehicle grille of  FIG. 1 ; 
       FIG. 3  is a cross-sectional view of the vehicle shield along  3 — 3  of  FIG. 2 ; and 
       FIG. 4  is a cross-sectional view of the vehicle shield along  4 — 4  of  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIG. 1 , a vehicle shield according to the invention is shown at reference numeral  40  attached to the hood  30  of a motor vehicle  10 . The motor vehicle  10  in the depicted embodiment is a 2004 Ford F150 pickup truck  12 . The truck  12  includes a grille  60  that is attached to the hood  30  such that when the hood is opened the grille  60  is raised with the hood  30 . It should, however, be appreciated that the vehicle shield can be adapted to be attached to vehicles  10  wherein the hood  30  and the grille  60  are not attached. 
   As addressed in the background, later model vehicles generally feature thinner and lighter hood designs as compared to older model vehicles. For example, the hood  30  on the Ford F150  12  features a double-layered aluminum construction. When the truck  12  is driven at high speeds, such as in excess of 80 miles per hour, the corners  34  and  32  of the hood  30  have a tendency to flutter. When standard shields or deflectors are attached to the truck  12  they impart forces on the hood  30  and influence the air flow around the hood  30  thereby generating an increased level of flutter at the rear corners  34  and  32  of the hood  30 . In contrast, installing the shield  40  of the present invention to a truck  12  improves the airflow characteristics around the hood  30  and decreases hood flutter. 
   Referring to  FIG. 2 , the vehicle shield  40  is shown in an exploded assembly view. The shield  40  is shown between the hood  30  (below) and the grille  60  (above). The shield  40  includes a hood protector region  44  and an attachment region  46 . The hood protector region  44  protects the hood  30  from, among other things, road debris and bugs. In the embodiment shown, the hood protector region  44  has a length Ls that is greater that the width W H  of the hood  30 . As such, the hood protector region  44  protects more than the hood  30  and portions the truck  12  directly behind the hood  30 . The majority of the hood protector region  44  remains exposed when the hood  30  of the truck  12  is in a closed position as shown in  FIG. 1 . 
   Still referring to  FIG. 2 , the hood attachment region  46  includes portions of the shield  40  that are used to attach the shield  40  to the truck  12 . The hood attachment region  46  shown in  FIG. 2  includes the first hood attachment flange  48 , second hood attachment flange  50 , and grille engagement flange  52 . The above listed flanges  48 ,  50 , and  52  are shown separated from each other by portions of the hood protector region  44 . Nevertheless, it should be appreciated that even though the hood attachment region  46  in the depicted embodiment is not contiguous, the hood attachment region  46  in alternative embodiments may be contiguous. In addition, though the hood protector region  44  and the hood attachment region  46  are shown as being formed of a single continuous sheet of material, in alternative embodiments the hood protector region  44  and the hood attachment region  46  can comprise separate and distinct structural members that are attached to each other via fasteners or other means. In the embodiment shown, the majority of the hood attachment region is hidden from view when the hood  30  is in the closed position as shown in  FIG. 1 . 
   A plurality of grille engagement flanges  52  are shown extending from the hood protector region  44 . The grille engagement flanges  52  are constructed to be sandwiched between the hood  30  and the grille  60 . Installing the shield  40  includes the step of separating the grille  60  from the hood  30 . During installation, brackets  62  can be loosen or completely removed from the bracket receiving location  67  on the underside  39  of the hood  30 . Once the grille engagement flanges  52  have been positioned, the grille  60  can be re-secured to the hood  30  by tightening or reattaching the fasteners  68  of the brackets  62  and also the grille fasteners  64 . It should also be appreciated that the hood shield  40  could be installed during the initial assembly of the vehicle  10 . 
   In the embodiment shown, the shield  40  includes six tabs that are spaced apart to allow grille fasteners  64  shown as bolts  65  to pass between engagement flanges  52  and through apertures  69  in the hood  30  for engagement with nuts  66  at the underside  39  of the hood  30 . It should be appreciated that many other arrangements of the grille engagement flanges  52  are possible. For example, the grille engagement flange  52  could be a single large flange with apertures therein to allow the grille fasteners  64  to pass through to engage nuts  66  at the underside  39  of the hood  30 . 
   The first hood attachment flange  48  and the second hood attachment flange  50  are shown near the ends of the shield  40  in the first end portion  47  and second end portion  49 , respectively. The first and second hood attachment flanges  48  and  50  are mirror images of each other. Therefore, for simplicity, the description regarding the attachment flanges  48  and  50  references only the first flange  48 . 
   The attachment flange  48  is constructed to extend from the hood protector region  44 . During installation of the shield  40 , aperture  51  in the first hood attachment flange  48  is aligned with an aperture  33  in the underside  39  of the hood  30 . The aperture  51  is shown to be a slot to provide for some lateral adjustment of the shield  40  relative to the truck  12 . Laterally adjusting the shield  40  may be necessary due to manufacturing tolerances associated with the truck  12  and also the shield  40 . Once the apertures  51  and  33  are aligned, a fastener  54  (shown as a pushpin  53 ) is manually inserted through both apertures. When the pushpin  53  is inserted into the apertures  51  and  33 , the pushpin  53  expands and secures the first hood attachment flange  48  to the underside  39  of the hood  30 . The use of the pushpins  53  is preferred since it allows the step of attaching the hood attachment flange  48  to be accomplished without using tools. Nonetheless, it should be appreciated that the use of many alternative fasteners  54  are possible. For example, the fasteners  54  could also be ordinary sheet metal screws. 
     FIG. 3  is a cross-section of the first hood attachment flange  48  along line  3 — 3 . As shown, the hood attachment flange  48  is contoured. The flange  48  includes a number of bends  55 ,  56 ,  57 , and  58 . These bends, otherwise referred to as contours or ridges, are for clearance in that they are sized and configured to prevent the first hood attachment flange  48  from interfering with or otherwise hindering the closing of the hood. In addition, the bends  55 ,  56 ,  57 , and  58  improve the stiffness of the flange to prevent excessive deflection thereof. 
     FIG. 4  is a cross-section of the shield  40  attached to a truck  12  along the line  4 — 4 . Also in  FIG. 4  for comparison purposes is the profile of prior art hood shield  100 . As compared to the shield  100  of the prior art, the shield  40  of the present invention is lower profiled and more “pulled back.” The construction of the shield  40  improves the airflow characteristics around the rear corners  32  and  34  of the hood  30  and also decreases the distortion forces imposed on the hood  30  by the shield  40 . 
   The shield  40  includes a leading surface  70  which is the surface of the shield  40  that first contacts the air that is deflected by the shield  40  while the truck  12  is in forward motion. Since the end portions  47  and  49  of the shield  40  are bent backwards conforming to the curvature of the front end of the truck  12 , the leading surface  70  is located at the center or middle of the shield  40 . Conversely, the trailing surface  71  is the surface of the shield  40  that contacts the deflected air immediately before the air completely passes over the shield  40  when the truck  12  is moving forward. A trailing edge  72  is the periphery edge of the hood protector region  44  nearest the back of the truck  12 . Unlike the trailing surface  71 , the trailing edge spans the entire length of the shield  40 . A portion of the trailing edge  72  defines the rear boundary of the trailing surface  71 . 
   In the embodiment shown, the trailing surface  71  is within 1½ inches away from the hood  30  when the shield  40  is installed and the truck  12  is stationary. Most preferably, the trailing surface  71  is positioned 1⅛ inches from the hood  30 . The above measurement is taken at the direction that defines the shortest distance between the trailing surface  71  and the hood  30  (referenced in  FIG. 4  as “D”). It should be understood that the distance between the trailing edge  72  and the hood  30  may vary depending on where along the shield  40  the measurement is taken. In the embodiment shown, the shield  40  is contoured to follow the contours of the truck  12  in that the end portions  47  and  49  drop lower to match the down left and right sides of the hood  30 .  FIG. 4  also shows a tangent line  73  to the trailing surface  71 . Preferably, the tangent line  73  defines an angle θ less than or equal to 30 degrees. The angle is measured relative to a horizontal plane relative to the truck  12 . Most preferably, the tangent line  73  defines an angle θ less than or equal to 20 degrees from the horizontal reference plane. 
   The shield  40  is preferably manufactured from a sheet comprising a polymer composition. The polymer composition that can be used according to the invention preferably includes a polymer that provides the desired degree of flexibility and rigidity so that the shield can minimize the forces that cause hood flutter while defecting air and road debris from the hood  30  of the truck  12  A preferred plastic material is one that provides vehicle shield  40  that functions well under conditions of use. An exemplary plastic material that can be used includes polycarbonate polymer and mixtures of polycarbonate polymer with other polymers. Preferably, the shield  40  is manufactured using a match mold thermoformed process. The plastic sheet preferably has a thickness that provides the vehicle shield with sufficient rigidity to withstand the wind pressures caused by being placed on the hood of a motor vehicle and will resist fluttering. The plastic sheet preferably has a thickness of between about 2 to 3 millimeters. 
   The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.