Abstract:
A weld nut has weld projections on both sides. The projections concentrate heat and melt when in contact with a component part, to form a lasting weld of the nut to the component part. Because there are weld projections on both sides of the nut, there is no risk that the nut will be placed against the component part upside down.

Description:
TECHNICAL FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to weld nuts and more particularly to an orientless weld nut.  
         BACKGROUND OF THE INVENTION  
         [0002]    Typical weld nuts have weld projections (small dimples that concentrate heat in controlled areas) on only one side. When the nut is welded to another component part, it is necessary to properly orient the nut so that the projections face the component part to which the nut is to be welded.  
           [0003]    This need to correctly orient the nut causes manufacturing and welding problems. First the nut must be placed on the component part over a pin that centers it on a hole. This can be done manually or mechanically. If done manually, the nut is often incorrectly oriented due to human error. Even when done mechanically, errors can result. If the nut is applied upside down, the nut will either not weld to the component part at all, resulting in immediate failure of the weld, or the weld will be weak and fail in shipping or in use or when a threaded fastener is screwed into the nut. This failure leads to high repair, scrap, and inspection costs.  
           [0004]    If the nut is located mechanically, there is an increased cost of equipment and maintenance. The mechanical devices used must orient and locate the nut. This can cause problems. Mechanical devices used to accomplish this include bowl feeders and rod type nut feeders. If the bowl feeder is dirty or improperly adjusted, the nuts can jam or be delivered upside down. If the pin wears or the rod type feeder is bent, worn or improperly adjusted, the nut can be mislocated off the pin. All of these problems will drive up the costs of maintenance, quality, inspection, repair and scrap, which have been traditionally high.  
         SUMMARY OF THE INVENTION  
         [0005]    The orientless nut of this invention simplifies the entire process. The nut has weld projections on both sides. The nut can still be located manually or mechanically. There is no longer a risk that the nut can be placed upside down. As long as the nut is on the locating pin, the weld will be good.  
           [0006]    One consideration that must be addressed to use the orientless nut involves the upper electrode that contacts the nut. The upper electrode must be recessed to provide clearance for the projections on the topside of the nut. Otherwise, the projections on the topside of the nut may weld to the electrode.  
           [0007]    One object of this invention is to provide a weld nut having the foregoing features and capabilities.  
           [0008]    Another object is to provide a method of welding a nut to a component part.  
           [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 be more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0011]    [0011]FIG. 1 is a perspective view of a weld nut embodying the invention;  
         [0012]    [0012]FIG. 2 is a plan view showing one side of the weld nut in FIG. 1;  
         [0013]    [0013]FIG. 3 is an edge view of the weld nut;  
         [0014]    [0014]FIG. 4 is a view partly in elevation and partly in section showing the weld nut being welded to a component part by a weld gun;  
         [0015]    [0015]FIG. 5 is bottom view of the upper electrode of the weld gun. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]    The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0017]    Referring now more particularly to the drawings and especially to FIGS.  1 - 3 , there is shown a metallic, electrically conductive weld nut  10  constructed in accordance with the invention, having a nut body  12  provided with a central hole  14  and formed with outwardly facing, parallel, external surfaces  16  and  18  on opposite sides thereof.  
         [0018]    Projecting outwardly from the surface  16  are a plurality of weld projections  20 . The weld projections  20  project outwardly from the surface  16  the same distance, are spaced apart from one another equal distances, and are arranged in a circle  22  concentric with the central axis  24  of the nut. The surface  16  has a circular area  26  radially outwardly of and surrounding the circle  22  of weld projections, the circular area  26  being flat and intended to be engaged by a surface of a welding electrode as more fully described hereinafter. The surface  16  also has a circular pilot  29  extending outwardly therefrom around the central hole  14 .  
         [0019]    The opposite side of the nut has a plurality of weld projections  28  which project outwardly from the surface  18 . The weld projections  28  project outwardly from the surface  18  the same distance, which is the same as that for the projections  20  on the surface  16 , are spaced apart from one another equal distances, which is the same as the spacing of projections  20  on the surface  16 , and are arranged in a circle  30  concentric with the central axis  24  of the nut and of the same diameter as the circle  22 . The surface  18  has a circular area  32  radially outwardly of and surrounding the circle  30  of weld projections which is flat and intended to be engaged by a surface of a welding electrode as more fully described hereinafter. The surface  18  also has a circular pilot  34  extending outwardly therefrom around the central hole  14 .  
         [0020]    Referring now to FIGS. 4 and 5, there is shown a weld gun  36  having an upper electrode  38  and a lower electrode  40  employed for welding the nut body  12  to a metallic, electrically conductive component part  42 . The lower electrode has a flat upper surface  44  supporting the component part  42  in electrical contact therewith. The nut body  12  is placed over the component part  42  with the central hole  14  in the nut body aligned with an opening  46  in the component part and with one of its surfaces  16 ,  18 , in this instance the surface  16 , confronting the component part, and with the weld projections  20  in electrical contact with the component part.  
         [0021]    The upper electrode  38  has a flat bottom surface  48  which engages the radially outer circular area  32  of the surface  18  of the nut body in electrical contact therewith. The flat bottom surface  48  of the upper electrode has a central circular recess  50  of a greater diameter than the diameter of the circle  30  of weld projections  28  and of a depth which is greater than the height of the weld projections  28  so that the projections  28  are not contacted by any part of the upper electrode  38 . The pilot  29  is aligned with the opening  46  in the component part  42  and the pilot  34  extends up into the circular recess  50  in the bottom surface  48  of the upper electrode  38  and is out of contact with the upper electrode.  
         [0022]    The lower electrode  40  has a weld nut locating pin  52  which extends through the opening  46  in the component part  42 , through the central hole  14  in the nut body  12  and terminates in a central receptacle  54  extending upwardly from the base of the recess  50 . The locating pin  52  does not contact the upper electrode  38  to avoid short-circuiting.  
         [0023]    When current passes between the upper and lower electrodes, the weld projections  20  where heat is concentrated melt and weld to the surface of the component part  42 . Current passes from the upper electrode  38  into the nut body  12  through the relatively large circular area  32  thereof but without contacting the weld projections  28  on the surface  18  so that heat is not concentrated as it passes from the upper electrode into the nut body and therefore does not overheat the nut body and there is no welding of the upper electrode  38  to the surface  18  of the nut body.  
         [0024]    It will be understood that the nut body  12  could be placed over the component part  42  with its surface  18 , instead of surface  16 , confronting the component part  42  with the weld projections  28  in electrical contact with the component part, and the same result would be achieved, that is, the weld projections  28  on the surface  18  of the nut body  12  would melt and weld to the surface of the component part  42 , and the upper welding electrode  38  would not contact the weld projections  20  on the surface  16  of the nut body  12 . Hence, a good weld will be achieved no matter which way the weld nut is oriented.  
         [0025]    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.