Abstract:
A lug cap includes a detent along the inner wall. The detent has an engaging surface that begins shortly after a threaded portion of the lug cap ends. The engaging surface ramps up to a top surface that runs parallel to the inner wall. The lug nut engages the detent which prevents the rotation of the lug cap with respect to the lug nut by increasing the force required to loosen or tighten the lug cap from the lug nut.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to ornamentation for vehicular wheels. More specifically, the invention relates to a lug cap having retention detents to retain the lug caps on the lug nuts. 
     2. Description of the Related Art 
     Wheels are often adorned with ornamentation to make them more aesthetically pleasing. One wheel, the aluminum wheel, requires little ornamentation as it can be manufactured having a finish that requires little attention. 
     The aluminum wheel does not, however, have a counterpart lug nut. More specifically, the lug nut has remained a steel product. A lug cap must be used to cover the steel lug nut to allow it to provide the desired aesthetic appearance. Lug caps are retained on the lug nut through various means. It is difficult to design a retention system for the lug cap because it must not interfere with the overall design of the wheel and must result in little body and/or weight added to the overall design. This light-weight feature, coupled with the extreme harsh environment in which the lug caps exist, make it difficult to design a lug cap that will be retained on the lug nut. 
     SUMMARY OF THE INVENTION 
     A lug cap covers a lug nut having an outer lug nut surface and an outer threaded portion. The lug cap includes a cylindrical body having an inner wall and an outer wall. The cylindrical body extends between a nut engaging end and a distal end. The lug cap also includes a cover closing the distal end. An inner thread is fixedly secured to a first portion of the inner wall of the cylindrical body. The inner thread engages the outer threaded portion of the lug nut. A detent extends along a second portion of the inner wall of the cylindrical body. The detent engages the lug nut when the lug cap is rotated over the lug nut such that the inner thread of the lug cap engages the outer threaded portion of the lug nut. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Advantages of the invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein: 
     FIG. 1 is an exploded perspective view of a lug cap according to the invention with respect to a lug nut and a vehicle wheel; 
     FIG. 2 is a top view of one embodiment of the invention; and 
     FIG. 3 is a cross-sectional side view partially cut away of one embodiment of the invention securing a lug cap to a lug nut. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the Figures, a wheel assembly is generally indicated at  10 . The wheel assembly  10  includes a wheel  12 , a tire  14  and a plurality of lug nuts  16 . The lug nuts  16  secure the wheel  12  to a wheel hub  17  by being secured to a plurality of lug studs  18 . The lug nuts  16  are secured to the lug studs  18  through a threading engagement therebetween. 
     The invention, a lug cap, is generally indicated at  20 . The lug cap  20  is used to decoratively cover the lug nuts  16 . The lug cap  20  improves the look of the lug nut  16  by covering it. The lug cap  20 , unlike the lug nuts  16 , may be fabricated from a material other than steel. This allows the lug cap  20  to have an improved finish over the steel lug nuts, avoiding the expense of finishing the steel nuts, or to have a finish that matches the finish of an outboard surface  22  of the wheel  12 . The finish on an outer wall  24  of the lug cap  16  may complement the finish of the wheel  12 . In many instances, the finish on an outer wall  24  of the lug cap  16  will match the finish of the outboard surface  22  of the wheel  12 . 
     The lug cap  20  includes a cylindrical body  26 . The cylindrical body  26  extends between the nut engaging end  28  and a distal end  30 . The cylindrical body  26  defines an inner wall  32  and the outer wall  24  of the lug cap  20 . The inner wall  32  is divided into at least two portions  34 ,  36 . The first portion  34  of the inner wall  32  is disposed adjacent to and spaced from the nut engaging end  28 . The first portion  34  includes an inner thread  38 . The inner thread  38  is designed to engage an outer thread  40  of the lug nuts  16 . The threading engagement between the inner  38  and outer  40  threads secures the lug cap  20  to the lug nut  16 . 
     The second portion  36  of the inner wall  32  is disposed between the first portion  34  and the distal end  30 . In the preferred embodiment, the first  34  and second  36  portions of the inner wall  32  are mutually exclusive. It should be appreciated by those skilled in the art that the two portions  34 ,  36  may, in some designs, extend into each other or overlap. 
     The second portion  36  of the inner wall  32  includes one or more detents  42 . The detent  42  is designed such that a force required to move the lug cap rotationally with respect to the lug nut  16  will have to be great. This force is greater than the force that may be generated to overcome the frictional forces created by the inner  38  and outer  40  threads. The detent  42  will, therefore, necessitate a greater force to loosen and/or tighten the lug caps  20  than that which is required by the lug caps of the prior art. 
     Each detent  42  is generally rectangular in shape and extends coaxially with the cylindrical body  26 . The detent  42  has a top surface  44  that extends generally parallel to the inner wall  32  at a height sufficient to engage the lug nut  16  at the points  45  of its hexagonal cross section. The detent  42  also includes two side surfaces  46  that extend between the inner wall  32  and the top surface  44 . The two side surfaces  46  are generally perpendicular to the inner wall  32 . 
     The detent  42  also includes an engaging surface  48 . The engaging surface  48  extends from the inner wall  32  to the top surface  44 . More specifically, the engaging surface  48  has a height equal to the height of the top surface  44  at the portion of the engaging surface  48  that abuts the top surface  44  and has a minimal height at the portion of the engaging surface  48  that is disposed adjacent the inner thread  38 . The engaging surface  48  rises from the inner wall  32  at an incline. Therefore, the profile of the detent  42  is small starting at a portion disposed adjacent the inner thread  38  and increases until it plateaus at the top surface  44 . In the preferred embodiment, the detent  42  is a solid structure. It may be appreciated by those skilled in the art that the detent  42  may be hollow. In yet another alternative embodiment, the detent may be fabricated from two ribs having a profile matching that of the detent  42 . In this alternative embodiment, the top surface  44  and the engaging surface  48  would be replaced by the top edges of the ribs. In other words, the edges of the ribs would define planes that would match the top surface  44  and the engaging surface  48 . 
     The lug cap  20  also includes a cover  50  that closes the distal end  30  of the cylindrical body  26 . The lug cap cover  50  hides the lug nut  16  from view. The detents  42  may extend into the cover  50  or end proximal thereto. 
     In the embodiment shown in the Figures, two detents  42 ,  42   a  are shown. Each of these two detents  42 ,  42   a  extend along the inner wall axially and parallel with a longitudinal axis defined by the cylindrical body  26 . Further, the second detent  42   a  extends along the inner wall  32  at a position other than a position being a multiple of sixty degrees from the detent  42 . More specifically, the detents  42 ,  42   a  are positioned within the cylindrical body  26  such that they are not positioned apart by a multiple of sixty degrees. This ensures that the second detent  42   a  will be operational if a portion of the lug nut  16  passes by the detent  42  after it has been engaged thereby. This prevents the lug nut  16  from rotating sixty degrees before it engages the detents  42 ,  42   a  again. Further, if the user were to leave the lug cap  20  in a rotational position where the detent  42  has been positioned exactly upon a lug nut point  45 , with time, temperature and load, plastic parts would exhibit an inelastic deformation which would permanently reduce the detent force of that particular detent. In this case, the second detent  42   a  would serve to perform the function. 
     The invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. 
     Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.