Abstract:
Integrally stiffened extruded metal panels for ground vehicles are provided. The panels may be extruded in the form of a tube, then cut and un-rolled to provide the desired shape, e.g., for a sidewall or top wall of a ground vehicle such as a railway car. In a preferred embodiment, the integrally stiffened extruded panels have widths and lengths sufficient to cover substantially the entire height and length of the ground vehicle, thereby eliminating seams along the sidewalls of the vehicle.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]    This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/348,848 filed Jan. 14, 2002. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to the use of integrally stiffened extruded panels in vehicles such as railway cars.  
         BACKGROUND INFORMATION  
         [0003]    Exterior panels of conventional ground vehicles, such as side panels of railway cars, have been made from several sheets that are welded together. The use of such multiple welded sheets has led to safety concerns and has resulted in increased fabrication costs and vehicle weight.  
         SUMMARY OF THE INVENTION  
         [0004]    An aspect of the present invention is to provide an integrally stiffened ground vehicle panel comprising an extruded exterior metal panel, and co-extruded interior metal stiffeners connected to the panel.  
           [0005]    Another aspect of the present invention is to provide a method of making an integrally stiffened ground vehicle panel comprising co-extruding an exterior metal panel and interior metal stiffeners.  
           [0006]    A further aspect of the present invention is to provide an integrally stiffened ground vehicle panel assembly comprising a first panel including an extruded exterior metal panel with co-extruded interior metal stiffeners, and a second panel connected to an edge of the first panel.  
           [0007]    These and other aspects of the present invention will be more apparent from the following description.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 is a cross sectional view of a portion of a railway car having integrally stiffened extruded aluminum side panels and an integrally stiffened extruded aluminum top panel in accordance with an embodiment of the invention.  
         [0009]    [0009]FIG. 2 is a cross sectional view of an aluminum extrusion including stiffeners on the outside of the tubular extrusion.  
         [0010]    [0010]FIG. 3 is a cross sectional view of a portion of an integrally stiffened extruded aluminum panel after the panel has been cut and un-rolled from the tubular shape shown in FIG. 2. 
     
    
     DETAILED DESCRIPTION  
       [0011]    [0011]FIG. 1 is a cross sectional view of a portion of a railway car  10  which includes a sidewall  20  comprising an integrally stiffened extruded side panel  22  and a top or roof  30  comprising an integrally stiffened extruded top panel  32  in accordance with an embodiment of the present invention. Although not shown in FIG. 1, the railway car  10  includes another integrally stiffened extruded side panel attached to the top panel on the opposite side of the car. The sidewall  20  also includes an interior sidewall  23  made of metal, plastic, composite, or the like. The volume between the integrally stiffened extruded side panel  22  and the interior sidewall  23  may preferably be filled with conventional thermal insulation and/or sound insulation materials.  
         [0012]    The side panel  22  may be attached to the top panel  32  by any suitable means such as mechanical fasteners or welding. For example, the edges of the side panel  22  and top panel  32  may be joined by friction stir welding. As shown in FIG. 1, the weld areas may be located on the roof of the railway car  10  such that the side panel  22  wraps around the upper corners of the car  10 .  
         [0013]    The integrally stiffened extruded side panel  22  and top panel  32  may be made of any suitable material, preferably an aluminum alloy. For example, the alloy may comprise a conventional aluminum alloy with scandium alloying additions. The floor  40  of the railway car  10 , as shown in FIG. 1, may have any desired structure and may be made from any suitable material, such as an extruded aluminum-scandium alloy. Lithium may optionally be added to such Al—Sc alloys. Some suitable aluminum alloys include 7X5X, 7X1X and 7X0X alloys, e.g., alloy 7055. The railway car  10  may be mounted on a conventional undercarriage  50 .  
         [0014]    [0014]FIG. 2 is a cross sectional view of an integrally stiffened extruded pipe  21 . The extruded pipe  21  is also shown in phantom in FIG. 1. In the embodiment shown in FIG. 2, the extruded pipe  21  includes a panel  24  and integrally formed stiffeners  26  extending from the surface of the panel  24 . Although several T-shaped stiffeners  26  are shown in FIG. 2, any other suitable number or shape may be used for the stiffeners. The extruded pipe  21  may have any suitable diameter, e.g., from less than 1 foot to greater than 5 feet, and may have any suitable length, e.g., from less than 1 foot to 50 or 100 feet, or more.  
         [0015]    As shown in FIG. 3, the extruded pipe of FIG. 2 may be cut by conventional metal cutting techniques and un-rolled to provide the desired shape for the vehicle panels. The portion of the panel shown in FIG. 3 is substantially flat. However, any other suitable panel shape may be provided. For example, the extruded pipe  21 , or a portion thereof, may be formed into a side panel shape  22  as shown in FIG. 1. Furthermore, the extruded pipe, or portion thereof, may be formed into a top panel  32  as shown in FIG. 1.  
         [0016]    As shown in FIG. 3, the extruded exterior panel  24  may have a typical thickness T P  of from about 0.03 to about 0.3 inch. The integral stiffeners may have thicknesses of from about 0.03 to about 0.3 inch. For example, the integral stiffeners  26  shown in FIG. 3 are generally T-shaped, with a base portion  26   b  and a cross member  26   c . The base portion  26   b  may have a typical thickness T B  of from about 0.03 to about 0.3 inch, and a height H of from about 0.5 to about 2 inches. The cross member  26   c  may have a typical thickness T C  of from about 0.05 to about 0.3 inch, and a typical width W C  of from about 0.5 to about 2 inches. The spacing S of the stiffeners  26  along the panel  24  may typically range from about 1 to about 10 inches. In a particular embodiment, T P  may be about 0.076 inch, T B  may be about 0.072 inch, T C  may be about 0.153 inch, W C  may be about 1.067 inch, H may be about 1.27 inches, and S may be about 4.64 inches.  
         [0017]    The side panel  22  and top panel  32 , e.g., as shown in FIG. 1, may have similar or different configurations. Thus, the size, shape and/or spacing of the integral stiffeners  26  may be the same or different for the side and top panels. Furthermore, the thickness and/or gauge of the side and top panels may be the same or different. Also, the extruded pipe  21  used for the side panel may be the same or different from the extruded pipe used for the top panel. For example, if the side panel  22  has a greater width than the top panel  32 , the extruded pipe  21  from which the side panel  22  is formed may have a greater diameter D than the extruded pipe  21  from which the top panel  32  is formed. Alternatively, the extruded pipes  21  may have the same diameter D, but the pipe used to form the top panel  32  may be cut or otherwise divided into two or more panels, each of which is used to form a single top panel  32 .  
         [0018]    The extruded pipe  21  may have any desired length. For example, the length may be selected in order to minimize the number of panels required to cover the length of the ground vehicle  10 . For instance, an entire side and/or top panel of a rail car as shown in FIG. 1 may be made from a single extrusion. In this case, the side and/or top panel may have a length approximating the length of the rail car or other ground vehicle.  
         [0019]    Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention.