Abstract:
A wheel lock mounted for preventing removal of the wheel from the axle includes a cup shaped base portion with an opening to receive a wheel stud for threaded engagement with a lug nut to clamp the base portion to the wheel. A cup shaped cover portion nests within the base portion to enclose the stud and lug nut. A key actuated locking member extends simultaneously through the base and cover portions to prevent separation. The cover portion interlocks with the locking portion to prevent forced rotation of the cover portion relative the base portion. The contour of the base portion or the positioning of the locking member may be configured to prevent rotating the device about the stud. The cover portion may include a flange that bears against the rim of the base portion giving the wheel lock a contiguous exterior surface that is difficult to pry apart.

Description:
REFERENCE TO RELATED APPLICATION 
   This application claims priority to provisional application No. 60/977,436 filed on Oct. 4, 2007, the disclosure of which is incorporated herein by reference. 

   BACKGROUND 
   The present invention relates to wheel locks for limiting the removability of the lug nuts from a vehicle wheel. 
   Truck wheels are secured to truck axles by lug nuts threaded onto an array of threaded posts or studs projecting from the axle hub. The lug nuts are engaged by a simple wrench, socket, or tire tool. Just as simply, the lug nuts can be removed by thieves intent on stealing the valuable tires on the wheel. This is problematic because tires are an expensive component of any truck, especially 18-wheelers. 
   Efforts have been made in the past to provide devices to prevent unwanted removal of the lug nuts holding the wheel on the axle. Any such device must be easy to use without interfering with the ability to tighten the lug nuts completely. While many prior devices cover and protect a lug nut from easy removal, the devices themselves are subject to being pried apart or open to allow access to the lug nut within. 
   Therefore a need exists for a wheel lock that is easy to use and resists improper removal. 
   SUMMARY 
   A wheel lock that is virtually tamper proof, short of complete destruction of the device includes an overlapping or nesting cup structure between a base portion and a cover portion in which the peripheral wall of the cover portion is fully contained within the peripheral wall of the base portion. The base portion may include a contoured surface that prevents removal of the device by rotating the base portion about the stud. The cover portion includes a circumferential flange that overlaps the upper rim of the base portion to limit pry point access. 
   The locking portion includes a locking pin that passes through openings in both the base portion and the cover portion. The locking portion also prevents the device from being rotated about the stud for unauthorized removal. In one embodiment, the cover portion includes an extension in the form of a wing and notch structure that interlocks with the locking portion. In another embodiment, the cover portion includes an interlock element that engages an opening in the locking portion. In both embodiments the rotation of the cover portion relative to the base portion is limited to prevent a would-be thief from shearing the locking pin. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a perspective view of the wheel lock installed on a truck wheel. 
       FIG. 2  is a perspective view of the wheel lock installed on a truck wheel depicting the interlocking notch. 
       FIG. 3  illustrates a perspective view of the wheel lock, with the locking pin extended through the base portion. 
       FIG. 4  illustrates a cutaway view of the wheel lock in the locked orientation, a lug nut secures the base portion to a wheel stud and the locking pin extends through the base portion and the cover portion. 
       FIG. 5  depicts a cutaway view of the base portion having a base plate with a surface contour to match the surface contour of the wheel. 
       FIG. 6  depicts a side view of the cover portion including a protrusion and an interlock element. 
       FIG. 7  illustrates a top view of the base portion and the locking portion with the locking portion having a cavity to accept an interlock element. 
   

   DETAILED DESCRIPTION 
   For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and described in the following written specification. It is understood that no limitation to the scope of the invention is thereby intended. It is further understood that the present invention includes any alterations and modifications to the illustrated embodiments and includes further applications of the principles of the invention as would normally occur to one skilled in the art to which this invention pertains. 
   In accordance with one embodiment of the present invention, a wheel lock  10  is mounted to a lug nut N of a truck wheel W, as shown in  FIGS. 1 and 2 . Even though a truck wheel W has many lug nuts N, a user needs only one wheel lock  10  per wheel W. It can be appreciated that locking one lug nut N against removal in effect locks the wheel W to the axle, even if all of the other lug nuts N are removed. 
   The details of one embodiment of the wheel lock  10  are illustrated in  FIGS. 3 and 4 . In particular, the wheel lock  10  includes a base portion  12 , a cover portion  14  and a locking portion  16 . The base portion  12  includes a base plate  20  with a hole  22  for receiving a threaded stud S of the vehicle wheel W, as shown in  FIG. 4 . In use the base plate  20  is mounted over the stud S and bears against the portion of the wheel surrounding the stud. The nut N is then threaded onto the stud S and tightened against the base plate  20  to lock the base portion  12  to the wheel. The base plate  20  may incorporate a surface finish around the hole  22  to enhance the frictional engagement of the nut with the base plate and thereby resist unthreading of the lug nut from the stud. 
   In the illustrated embodiment, the base plate  20  is shown as being generally flat. However, in another embodiment, as illustrated in  FIG. 5 , the base plate  20 ′ may have a contour that matches the contour of the wheel W. The contoured base plate  20 ′ interlocks with the contour of the wheel W to resist rotation of the base portion  12  should a person attempt to remove the device  10  and the lug nut N by rotating the entire device  10  about the stud S. The base plate  20  is shown with an exemplary contour, but other contours are possible depending on the contour of the particular wheel W upon which the device  10  is to be mounted. 
   Attached to or integral with the base plate  20  is an outer peripheral wall  25  that defines an interior surface  27 . The base plate  20  and outer peripheral wall  25  thus form a cup that is mounted over the stud S with the opening of the cup facing outward. This cup is configured to mate with a downward facing cup, in the form of the cover portion  14 . The figures herein illustrate the base plate  20  and outer peripheral wall  25  in a circular configuration; however, the device  10  is not limited to only circular configurations. For example the base plate  20  and outer peripheral wall  25  could have an elliptical or even a multi-sided periphery. 
   The cover portion  14  includes an inner peripheral wall  32  that is sized to fit snugly within the outer peripheral wall  25 . Preferably, the inner peripheral wall  32  is configured for a close running fit with the interior surface  27  of the outer peripheral wall  25 . This close fit prevents dislodgement or destruction of the wheel lock  10  by a would-be thief, and also helps protect the lug nut N from the elements. It is also contemplated that the outer peripheral wall defines a depth to the base plate and that the inner peripheral wall of the cover portion is sized to extend substantially along the entire depth of the first peripheral wall—i.e., so that the lower edge  35  of the cover portion resides closely adjacent the base plate  20  when the two portions are in nested engagement. 
   Attached to or integral with the inner peripheral wall  32  is a cover plate  30 . The cover plate  30  is larger than an outer extent of the inner peripheral wall  32  so that the cover plate  30  forms a flange  34  around the inner peripheral wall  32 . This flange  34  is configured to bear against the upper rim  26  of the outer peripheral wall  25  of the base plate  20 , as illustrated in  FIGS. 2 and 4 , and makes the cover portion  14  extremely resistant to tampering. In particular, the flange  34  has an outer dimension that is no greater than, and preferably slightly less than, the outer dimension of the outer peripheral wall  25 . The cover portion  14  will thus form a flush interface with the upper rim  26  of the outer peripheral wall  25 , with the interface having no points that provide access for a prying implement, such as a screwdriver or crowbar. Even if a thief were to insert a prying tool between the flange  34  and the upper rim  26 , the overlapping relationship between the inner peripheral wall  32  and the outer peripheral wall  25  prevents the cover portion  14  from being pried apart or de-nested from the base portion  12 . In particular, the length of overlap between the peripheral walls  32  and  25  makes it virtually impossible to pry the cover portion  14  away from the base portion  12  enough to dislodge the inner wall  32  from the outer wall  25 , or to disconnect the inner wall  32  from the locking member  46 . 
   Additionally, the flange  34  forms a weather-tight joint between the cover plate  30  and the upper rim  26  of the outer peripheral wall  25 . The weather-tight joint prevents road debris and salt from contacting the lug nut N and stud S, which could potentially make the lug nut N difficult to remove. Alternatively, the cover plate  30  may define an opening  39  to permit inspection of the lug nut N within the device  10 . The central opening  39  is small enough so that the opening  39  cannot be used as an effective pry point in an attempt to remove the locked device  10 . 
   The locking portion  16  includes a lock body  40  that is attached to or integral with the base portion  12 . The body  40  preferably has at least two interdigitating faces  42 , and most preferably has a hexagonal shape. The body  40  carries a lock cylinder  44  within a first opening in the body  40 , and most preferably recessed therein. As shown in  FIG. 2 , the lock cylinder  44  is readily available for key access when the device  10  is mounted to a wheel W. The lock cylinder  44  is of the type that includes a locking member  46 , such as a pin, that projects from the locking portion  16  when a user turns a key  50 . The locking member  46  is arranged to pass through an opening  28  in the outer peripheral wall  25  of the base portion  12 , as depicted in  FIG. 3 . Moreover, when the cover portion  14  is mounted over the base portion  12 , the locking member  46  also extends through a hole  33  in the inner peripheral wall  32  of the cover portion, as shown in  FIG. 4 . The holes  28  and  33  is positioned so that the cover plate  30  rests substantially flush with the upper rim  26  of the base portion  12  when the locking member  46  extends through the two holes. Again, this flush fit provides no purchase for a prying tool. 
   The locking member  46  may be a cylindrical pin, as shown in  FIGS. 3-4 , or may present an angled contour configured to draw the cover portion  14  down into the base portion as the pin extends through the hole  33 . The locking member may have other configurations depending upon the nature of operation of the lock cylinder  44 . For instance, in some embodiments the lock cylinder may incorporate a rotating locking portion that rotates downward (or upward) and outward from the cylinder. In this embodiment, the holes  28  and  33  can be modified to form aligned slots that receive the modified locking portion as it rotates toward the base and cover portions. 
   When the device  10  is mounted upon the wheel the locking portion  16  prevents a person from rotating the device  10  about the stud S. In one embodiment, the locking portion  16  abuts the curvature of the wheel W to prevent rotation. In another embodiment, the locking portion  16  prevents rotation by abutting a wheel hub that projects through an opening in the wheel W, as illustrated in  FIG. 2 . In both embodiments, the locking portion  16  prevents rotation so that friction between the base plate  20  and the lug nut N cannot be utilized to remove the lug nut N while the device  10  remains secured to the stud S. 
   The cover plate  30  interlocks with the locking portion  16  to prevent the cover portion  14  from rotating relative the base portion  12 , which could potentially shear the locking portion. In one embodiment, the cover plate  30  includes an extension in the form of wings  36  defining a notch  38  therebetween to mate with the interdigitating faces  42  of the locking portion  16 , as illustrated in  FIG. 2 . This interdigitation also establishes the alignment of the hole  33  in the cover portion  14  with the opening  28  in the base portion  12 , so that the locking member  46  may extend cleanly therethrough. Preferably, the base portion  12  and cover portion  14  are configured for substantially exact alignment of the holes so that extension or retraction of the locking member  46  occurs smoothly with no binding or friction. 
   The configuration of the wings  36  and their orientation in the cramped space between the interdigitating faces  42  and the outer wall  25  also virtually eliminates any space for a would-be thief to introduce a prying tool. In another embodiment, rotation of the cover portion is prevented with a locking portion  16 ′ modified to include a second opening or cavity  58  into which an interlock element  54  is inserted, as depicted in  FIGS. 6-7 . In this embodiment the cover plate  30 ″ includes a protrusion  56  that extends beyond the outer peripheral wall. The interlock element  54  is attached to or integral with the protrusion  56  and engages the cavity  58  in the locking portion  16 ′ when the cover portion  14 ′ is inserted into the base portion  12 . This engagement also establishes the alignment of the hole  33  in the inner peripheral wall  32  with the opening  28  in the outer peripheral wall  25 , so that the locking member  46  may extend cleanly therethrough. 
   In operation, a user positions the base portion  12  with a stud S extending through the hole  22  in the base plate  20 . A lug nut N is then tightened onto the stud S, thereby clamping the base portion  12  to the wheel W. The cover portion  14  is then nested with the base portion  12  with the wings  36  and notch  38  interdigitating with the faces  42  of the lock element  16  as shown in  FIGS. 3-4 , or with the interlock element engaged with the second opening in the lock element as shown in  FIGS. 6-7 . The cover portion  14  is placed fully within the base portion  12  until the flange  34  bears against the rim  26  of the outer peripheral wall  25 . In this position, the hole  33  is aligned with the opening  28 . Turning the key  50  activates the lock cylinder  44  by advancing the locking member  46  through the opening  28  and the hole  33 . The cover portion  14  thereby becomes locked to the base portion  12 . The key  50  is then necessary to unlock the cover portion  14  from the base portion  12  when a user desires to remove the lug nut N. 
   In a specific embodiment, the base portion  12  and cover portion  14  are formed from 0.1 inch thick stainless steel plate. The base plate  20  has a diameter of about 2.75 inches while the hole  22  for the stud S has a diameter of about 1.0 inches. The outer peripheral wall  25  has a height of about 2.25 inches, while the inner peripheral wall  32  has a height of about 1.75 inches. The wings  36  may extend about 0.75 inches from the inner peripheral wall  32  to interdigitate with the lock body  40 . The wings  36  may also be bent downward to limit further the space available to insert a prying tool. The locking member  46  can have a diameter of about 0.25 inches. 
   While the invention has been illustrated and described in detail in the drawings and foregoing description, the same should be considered as illustrative and not restrictive in character. It is understood that only the preferred embodiments have been presented and that all changes, modifications and further applications that come within the spirit of the invention are desired to be protected.