Abstract:
A grease nipple is installed in a modified dome nut to allow corrosion-retardant fluid to be squeezed into the spaces within the dome nut around the lug and exposed thread surfaces using a grease gun.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This non-provisional application for patent claims priority of U.S. provisional application Ser. No. 61/935,890 filed Feb. 5, 2014. 
     
    
     Statement Regarding Federally Sponsored Research or Development 
       [0002]    Not applicable. 
       NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not applicable. 
       REFERENCE TO A BIOLOGICAL SEQUENCE LISTING 
       [0004]    Not applicable. 
       BACKGROUND OF INVENTION 
       [0005]    1. Field of the Invention 
         [0006]    This invention is in the field of mechanical fasteners, more particularly in the field of threaded fasteners, and still more particularly in the field of fasteners exposed to the elements or other corrosive conditions. 
         [0007]    2. Description of the Related Art 
         [0008]    A very common fastener is the combination of a threaded nut and bolt. After a nut is fastened onto a bolt (or a threaded stud) and left exposed to air, their surfaces become corroded over an amount of time dependent on the material they are made of, the amount of moisture in the air, and the presence of electrolytes such as salts. After corrosion occurs, the amount of torque necessary to loosen the nut from the bolt can become significantly greater than that used to tighten the nut in the first place. 
         [0009]    Conditions for such corrosion are commonly found in the environment of vehicle wheel lug nuts and the threaded studs (lugs) onto which they are tightened. Moist air and salts easily access the lugs and lug nuts even when wheel covers or hub caps are in place. The result is that by the time it is necessary to loosen the lug nuts for tire rotation, the impact wrenches used can crack the studs or nuts, creating the possibility of mechanical failure at high speed. 
       BRIEF DESCRIPTION OF THE INVENTION 
     Objects of the Invention 
       [0010]    The object of the invention is to enable a high-viscosity grease or other protective fluid to be squeezed into all void spaces between a nut and bolt, particularly a lug nut and the corresponding wheel lug or stud, without loosening or removing the nut. 
         [0011]    Many lug nuts are in the form of an “acorn nut” or “dome nut” (see  FIG. 1 ) which cover all of the lug threads. In this case, an object of the invention is to provides a means for injecting protective fluid under the dome. 
       SUMMARY OF THE INVENTION 
       [0012]    A grease nipple is installed in a modified dome nut to allow corrosion-retardant fluid to be squeezed into the spaces within the dome nut around the lug and exposed thread surfaces using a grease gun. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a front view of a prior art dome nut used as a lug nut; 
           [0014]      FIG. 2  is the front view of the invention; 
           [0015]      FIG. 3  is a left end view of the invention; 
           [0016]      FIG. 4  is a right end view of the invention; 
           [0017]      FIG. 5  is a cross-sectional front view of the invention; and 
           [0018]      FIG. 6  is an exploded view of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    Referring now to the drawings, in which like features in the several figures are represented by like indicia used in this description,  FIG. 1  is a front view of a prior art dome nut used as a lug nut  1  to fasten a tire rim  2  to the wheel  3  of a vehicle (not shown). All parts shown in this and all other figures are metal. The lug nut  1  has a threaded lug bore (not visible) cut into its right end (in this view) and a domed left end  8  covering the threads at that end. A hole  4  in the rim  2  is placed over a threaded lug  5 , and when the rim  2  is fully seated on the lug  5 , the lug nut  1  is screwed tightly down onto the lug  5 . This compresses the flange  6  on the rim  2  tightly between the bevel  7  on the lug nut  1  and the wheel  3 . Fastening the rim to the wheel tightly in this manner keeps the lug nut  1  from loosening from the lug  5 , but the seal is not water tight; over time, corroding matter gets in between the rim  2  and the lug  5 . To solve this problem, putting a water tight (compressible) washer between the rim  2  and the wheel  3  and/or the bevel  7  comes to mind, but doing so would prevent tight frictional binding of metal against metal and would allow the lug nut  1  to loosen. 
         [0020]      FIG. 2  is the front view of the invention, a protectant-injectable nut, in this case a lug nut for holding tire rims on a vehicle wheel. It comprises a lug nut  1  also showing a bevel  7  at the right end in this view which performs the same function as in  FIG. 1 . 
         [0021]      FIG. 3  is a left end view of the invention. It shows the typical hexagonal profile  30  of a lug nut, but in place of the dome, a grease nipple  31  is screwed into the bottom of a grease gun bore  32 . A lug nut cap (not shown) may, within the scope of this invention, be optionally fitted to the left end of the nut to keep dirt from accumulating around the grease nipple  31 . 
         [0022]      FIG. 4  is a right end view of the invention. The bevel  7  for seating the lug nut surrounds this end as in a conventional lug nut. The usual threaded lug bore  40  is cut most of the way through so that the distal or bottom end  41  of the grease nipple  31  is visible. The central bore  42  of the grease nipple  31  can also be seen. 
         [0023]      FIG. 5  is a cross-sectional front view of the invention, Section A-A′ of  FIG. 4 . It shows the lug nut  1  with the grease gun bore  32  at the left end and the threaded lug bore  40  to fasten to the lug at the right end. An internal threaded bore  50  is shown joining the grease gun bore  32  and the threaded lug bore  40 . All three of these bores have centerlines that are shown collinear with each other and with the centerline B-B′ of the lug nut, however, it is within the scope of this invention that these bore holes not be collinear, so long as they form a continuous liquid passage. 
         [0024]    The grease nipple  31  is screwed into the internal threaded bore  50 ; however, it is within the scope of this invention to attach the grease nipple  31  to the lug nut  1  by other means, such as a friction fit, or even to fabricate the lug nut and grease nipple as a single piece of material. The grease gun bore  32  should be deep enough so that the grease nipple tip  52  is recessed within the grease gun bore  32  in order for the left face  53  of the lug nut  1  to protect it as the lugs revolve around the wheel axle (not shown). While this is a desirable feature, the scope of this invention does not require a grease gun bore this deep, or even one at all. If it is present, it is necessary that the grease gun bore have a diameter sufficient to accept the tip of a grease gun (not shown). It is within the scope of this invention that the grease gun bore  32  have a different shape (e.g., threaded, conical, dished, etc.) so long as it can accept the tip of a grease gun. The grease nipple  31  has a check valve in the form of a spherical check ball  54  which is normally held to the left in a closed position by a spring  55 . When it is desired to inject corrosion protectant fluid into the threaded lug bore  40 , the tip of a grease gun fitted with a cartridge of grease or other corrosion protectant is fitted onto the grease nipple  31  and squeezed. The pressure of the fluid pushes the check ball  54  to the right, creating a fluid passage through the center grease nipple bore  56  and into the interstices between the lug threads and the lug nut threads. Other types of check valves may be used within the scope of the instant invention. While a check valve in the grease nipple  31  is desirable, the scope of the invention does not require one, and a cap fitted to the grease nipple  31  and/or the left face  53  may be substituted for a check valve. A cap  57  is depicted having a grease nipple gripping part  58  and a left face gripping part  59 , both of which engage the grease nipple  31  and the left face  53  simultaneously when it is pushed to the right in this view. 
         [0025]    If desired, the threaded lug bore  40  may be pre-loaded with protectant fluid before the lug nut  1  is screwed onto the lug  5  (see  FIG. 1 ). It is recommended that the invention be used then anyway to force protectant fluid into all available spaces so that all surfaces, especially thread surfaces that will corrode and resist loosening, are covered with protectant. 
         [0026]      FIG. 6  is an exploded view of the invention giving a better view of the grease gun bore  32 , joining the internal threaded bore  50 , which in turn joins the threaded lug bore  40 .