Abstract:
A structural member of the present invention includes a substrate having portions defining an inwardly extending channel and a blow molded member in contact with the substrate. The blow molded member has portions that engage the portions of the substrate that define the inwardly extending channel such that the blow molded member is secured to the substrate.

Description:
TECHNICAL FIELD OF THE INVENTION  
         [0001]    This invention relates to a structural member formed of a metal and reinforced by a blow-molded member. More specifically, this invention relates to a structural member made of extruded metal with a blow-molded hollow plastic reinforcement located in the interior of the extruded metal.  
         BACKGROUND OF THE INVENTION  
         [0002]    Today&#39;s automotive design seeks new methods of manufacturing lighter components having increased structural rigidity. Such lightweight components find use in vehicle seats, cross car beams, support brackets, etc. It is also desirable to reduce the number of components in vehicles such that one component performs more than one function. With regard to vehicle cross car beams, much effort has previously focused on utilizing the structural integrity of the outboard register ducts to support the substrate. These previous designs typically required significant reinforcement with an additional steering column support bracket.  
         SUMMARY OF THE INVENTION  
         [0003]    In accordance with the preferred embodiment of the present invention, a structural member is formed of an extruded substrate reinforced by a blow molded member. In order to retain the blow molded member to the substrate, the substrate is provided with an inwardly extending channel formed therein. A portion of the blow-molded member engages the portions of the substrate that define the inwardly extending channel to secure the blow molded member to the substrate, such that the substrate is mechanically bonded to the blow-molded member.  
           [0004]    In another aspect of the present invention, the inwardly extending channel has a neck portion defining a first dimension and a body portion defining a second dimension, wherein, the first dimension of the neck portion is smaller than the second dimension of the body portion.  
           [0005]    In yet another aspect of the present invention, the inwardly extending channel is adapted to support a plurality of communication members therein.  
           [0006]    In still another aspect of the present invention, the inwardly extending channel is adapted to support a mounting device for attaching the structural member to another object.  
           [0007]    Further features and advantages of the invention will become apparent to one ordinary skilled in the art from the following discussion and the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a perspective view of a structural member illustrated as a cross car beam in accordance with the teachings of the present invention and showing in phantom an instrument panel as installed in a motor vehicle;  
         [0009]    [0009]FIG. 2 is a perspective view of the structural member in FIG. 1 shown alone;  
         [0010]    [0010]FIG. 3 is a cross sectional view of one embodiment of a structural member incorporating the principles of the present invention; and  
         [0011]    [0011]FIG. 4 is a cross sectional view of another embodiment of a structural member incorporating the principles of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0012]    Referring to FIGS. 1 and 2, an instrument panel and dashboard  10  (shown in phantom) having a structural member  12  embodying the principles of the present invention is shown therein. The instrument panel  10  and structural member  12  are installed in the interior of a motor vehicle. The structural member  12  is illustrated as a cross bar  14 . The cross bar  14  extends horizontally across the motor vehicle generally from the left A pillar  18  to the right A pillar  18 . Additionally, the cross bar  14  has an aperture  20  to accommodate a steering wheel and may have additional features to attach different components, such as a glove compartment, an audio system, a display for the climate control, a passenger airbag, etc.  
         [0013]    A support bracket  16  serves as an upright support for the cross bar  14 . The support bracket  16  is positioned substantially perpendicular to the cross bar  14  and is attached to the cross bar  14  at one end and attached to the floor (not shown) of the motor vehicle at the other end. The structural member  12  forms the backbone of the instrument panel and dashboard  10 .  
         [0014]    Although in the drawings the structural member  12  is shown and described as a cross beam  14 , it must be understood that the structural member  12  is not limited to use exclusively in this arrangement. The structural member  12  can be used in a variety of components in a motor vehicle. For example, it may be used as a duct for the air conditioning unit in a car, or fluid in the radiator support. Alternatively, the structural member  12  may be used in other application not relating to motor vehicles such as routing for electrical lines in a building walls etc.  
         [0015]    Referring to FIG. 3, the structural member  12  comprises an extruded substrate  22  and a blow molded member  24  located within and reinforcing the substrate  12 . Preferably, the substrate  22  is formed from a suitable metal such as aluminum, iron, copper or alloys thereof. The blow molded member  24  is preferably formed from materials such as plastic, plastic composite or thermoplastic resin such as PET or nylon.  
         [0016]    The substrate  22  is formed by extrusion, and an inwardly extending channel  26  in a wall portion  27  of the substrate  22  is part of the extrusion profile. Any appropriate number of inwardly extending channels  26  may be defined in the substrate, and three such channels  26  are shown herein as an example.  
         [0017]    The inwardly extending channel  26  is formed such that it is defined by a neck portion  28  and a body portion  30 . The neck portion  28  is adjacent to the wall portion  27  of the substrate  22  and defines a first outer dimension  32 . The body portion  30  extends from the neck portion  28  toward an interior of the substrate  22  and defines a second dimension  34 . This second dimension  34  is greater than the first dimension  32 , and the neck portion  28  forms an undercut relative to the body portion  30 .  
         [0018]    The body portion  30  such that portions  36  of the blow molded member  24  engage the inwardly extending channel  26  and wrap around the inwardly extending channel  26  adjacent the neck portion  28 . The portions  36  of the blow molded member  24  adjacent the neck portion  28  are secured in place by the larger body portion  30 , as shown in FIG. 3.  
         [0019]    The engagement of the blow molded member  24  and the inwardly extending channel  26  provides the necessary mechanical bond to hold the blow molded member  24  to the substrate  22 .  
         [0020]    The substrate  22  of the structural member  12  can have an open profile, such as that shown in FIG. 3, wherein the substrate  22  provides a substantially C-shaped profile. If the substrate  22  has an open profile, preferably the blow molded member  24  is further secured to the substrate  22  by using a portion of the blow molded member  24  to encapsulate an edge  42  of the substrate  22 , as shown by the circle designated by reference letter A of FIG. 3.  
         [0021]    Alternatively, the blow molded member  24  can be further secured to the substrate  22  by folding a flange portion  44  of the substrate  22  over onto the blow molded member  24 , as shown by the circle designated by reference letter B of FIG. 3. The substrate  22  can also have a closed profile, as shown in FIG. 4, wherein the substrate  22  has a substantially circular, or square, or rectangular shape, such that the substrate  22  presents a hollow tubular profile.  
         [0022]    The inwardly extending channel  26  can serve various other purposes within the vehicle and elsewhere. Referring to FIG. 3, the inwardly extending channel  26  can be adapted to support communication members  38 , such as electrical wiring, or fiber optic cable or other devices adapted to transport electrical current or signals, fluids, air, between various components within the motor vehicle. Further, the inwardly extending channel  26  can also be used to support a mounting device  40  that could be used to attach objects to the structural member  12 , or to mount the structural member  12  to another object.  
         [0023]    As a person skilled in the art will recognize from the previous description and from the figures and claims, modifications and changes can be made to the preferred embodiment of the invention without departing from the scope of the invention as defined in the following claims.