Abstract:
An L-shaped weld-fast bracket is disclosed for welding to thin sheet metal. The bracket has a surface which is configured to mate with the thin sheet metal having a depth being a multiple of the thickness of the sheet metal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Application No. 60/418,463 filed on Oct. 15, 2002. The disclosure of the above application is incorporated herein by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to a weldable bracket for sheet metal and, more particularly, to a thin L-shaped bracket for welding to very thin sheet metal.  
         BACKGROUND OF THE INVENTION  
         [0003]    Increased fuel economy requirements in the transportation industries are requiring lighter and lighter vehicles. As such, vehicle manufacturers are required to find weight reductions throughout the vehicle. One method of accomplishing such weight reduction is to reduce the thickness of sheet metals used to form the outer skin and interior portions of a vehicle&#39;s body.  
           [0004]    To couple sheet metal panels to other portions of the vehicle frame, thin flanges are typically welded to the sheet metal panel. Additionally, flanges are welded to sheet metal to function as electrical grounds or mounting locations for vehicle components such as wire harnesses. These weld flanges often are coupled to the sheet metal using weld guns to weld the weld flange perpendicular to the sheet metal. In this regard, the weld flange is typically planar and has a contact surface equal to the width and thickness of the flange.  
           [0005]    Often in situations where the sheet metal is thinner than the flange, the base sheet metal is so locally heated by the flange that marking occurs within the base sheet opposite the weld flange. Additionally, when subject to vary high welding currents, a through hole may be produced in the base sheet metal. This is especially true in sheet metal constructions when the sheet metal has a thickness of less than or equal to 1.2 mm. In situations where the electrical current to produce a weld is reduced so as not to cause destruction or marking of the sheet metal, the weld is not of a suitable strength to mount the sheet metal to a vehicle structure.  
         SUMMARY OF THE INVENTION  
         [0006]    Accordingly, it is an object of the present invention to provide a weld fast bracket which overcomes the deficiencies of the prior art. Specifically, an L-shaped weld-fast bracket is disclosed for welding to thin sheet metal. The bracket has a surface which is configured to mate with the thin sheet metal having a depth of from X to 5 times the thickness of the sheet metal base material. Where X equals the thickness of the bracket plus the thickness of the base material.  
           [0007]    In accordance with another embodiment of the invention, a weld bracket to sheet metal construction is provided. The sheet metal has a first thickness. The depth of a flange is the function of the first thickness. A weldment portion is provided between the flange and the base metal.  
           [0008]    In another embodiment of the invention, a method of coupling a bracket to a sheet metal base having a thickness less than 1.2 mm is provided. The method includes forming a flange on the bracket. The flange is then positioned so as to contact the sheet metal. Current is applied to the bracket while the bracket is being moved away from the sheet metal so as to form a welding arc. The bracket is then forced into a pool of weldment material.  
           [0009]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0011]    [0011]FIG. 1 is a side view of the bracket and base material according to the teachings of the present invention;  
         [0012]    [0012]FIGS. 2 a  and  2   b  represent an alternate embodiment of the invention; and  
         [0013]    [0013]FIGS. 3 a  and  3   b  represent the brackets shown in FIGS. 1 and 2 coupled to a sheet metal structure.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0014]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0015]    [0015]FIG. 1 depicts an angular weld bracket  10  which is welded to a base sheet metal component  12 . The weld bracket  10  has a thickness  14  of T br  while the sheet metal component  12  has a thickness  16  of T bm . The bracket has a flange  18  which is general perpendicular to a bracket body  20 .  
         [0016]    The flange  18  has a depth B and a width C. In circumstances where the thickness  16  of the sheet metal component  12  is greater than the thickness of the bracket  14  or the thickness of the sheet metal component is greater than 1.2 mm, then flange  18  is not needed and the flat bracket body  20  can be welded directly to the base material  16 . The bracket width C is from 1.0 to about 30 mm depending upon the strength needed.  
         [0017]    Under circumstances when the thickness of the bracket material  14  is greater than the thickness  16  of the sheet metal component  12  or the thickness of the sheet metal component  12  is less than or equal to 1.2 mm, then the depth of the base flange B is equal to a multiplication factor (X) times the thickness of the base material. In this regard, the depth of the flange is a function described below:  
         [0018]    t BM =Sheet Metal Base Material Thickness  
         [0019]    t BR =Bracket Material Thickness  
         [0020]    t BM &lt;t BR  or t BM &lt;1.2 mm  
         [0021]    B=xt BM    
         [0022]    y≦x≦5  
         [0023]    Y=t BM +t BR    
         [0024]    The lower limit for the multiplication factor (X) is equal to the thickness  16  of the bracket  14  plus the thickness of the sheet metal  12  base material, while the upper limit for multiplication factor is 5. It has been found that the multiplication of factor of 2 to 3 is preferred. These ratios are best applied to brackets  10  having a thickness  14  of greater than or equal to 0.5 mm up to and including 5 mm. Further, the ratios are most applicable to base materials having a thickness  16  of greater than or equal to 0.5 mm up to and including 1.20 mm.  
         [0025]    [0025]FIGS. 2 a  and  2   b  represent an alternate embodiment of the present invention. As shown, the bracket further has a pair of triangular side support members  22 . The bracket has a flange  20  which conforms to the size requirements as described for the embodiment of FIG. 1. In using the weldment area of the flange, heating of the base sheet metal is distributed over a greater area as opposed to the prior art. Damage to the surface of the sheet metal is reduced and the strength of the weld to surface interface is improved.  
         [0026]    [0026]FIG. 3 a  represents a welded construct according to teachings of the first embodiment of the invention. Shown is a weld bracket  10  coupled to the base  12  by a weldment portion  24 . As seen, the bracket  10  has a thickness  14  greater than the thickness of the sheet metal  16 . It is envisioned that the bracket  10  will be coupled to the sheet metal by the wetting of a majority of the flange  18  with molten metal.  
         [0027]    Similarly, FIG. 3 b  represents the weld bracket construct coupled to the sheet metal by the weldment portion  24 . The brackets  20  are coupled to the sheet metal using a drawn arc method. In this regard, a flange  20  is positioned against a surface of the sheet metal  12 . Welding current is applied to the bracket  10  or  20  and through the sheet metal. The bracket  10  or  20  is lifted slightly off the surface of the sheet metal  12  forming a welding arc therebetween.  
         [0028]    Molten metal is formed between the sheet metal  12  and the flange  18 . The bracket  10  or  20  is then plunged into the liquid metal and the welding current is removed, thereby coupling the bracket  10  or  20  to the surface of the sheet metal  12 .  
         [0029]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention. For example, it is envisioned that the base sheet metal can be a laminate construction formed of very thin layers of aluminum or steel separated at least partially by a non-conductive polymer layer.