Abstract:
A wheel nut assembly for fixing a wheel to a vehicle hub which includes a wheel nut with an internal thread; a wheel stud having an external thread to co-operate with the internal thread of said wheel nut and having an end portion adapted to project beyond the wheel nut which end portion includes axial grooves o ribs on its external surface; a retaining cap with internal grooves or ribs complementary to the external ribs or grooves on said wheel stud adapted to fit over said wheel stud and said wheel nut; and means to secure the retaining cap to said wheel nut. The retaining cap prevents rotation of the nut once it has been tightened In some embodiments an aesthetic cover is provided to improve the appearance of the wheel. This aesthetic cover may also be used to lock the retaining cap to the nu and provide an indication that the nut is securely fastened.

Description:
[0001]    This invention relates to wheel nuts for retaining vehicle wheels on the wheel hub and for ameliorating the risk of the nuts becoming loose. 
       BACKGROUND TO THE INVENTION 
       [0002]    In order to prevent wheel nuts loosening one approach has been to provide a stud for the nut that has an internal thread of opposite hand to the thread of the nut. Such an arrangement is disclosed in U.S. Pat. No. 6,916,144. 
         [0003]    Another proposal is to use a compression collar for, the nut as in U.S. Pat. No. 6,935,825. 
         [0004]    In these arrangements it is important to have tamper proof nut assembly that visibly indicates that the nut is tightened. In addition it is usual to provide an aesthetic cap or cover for the nut. 
         [0005]    It is an object of this invention to provide a tamper evident wheel nut arrangement that also enables the provision of a variety of aesthetic appearances. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0006]    To this end the present invention provides a wheel nut assembly for fixing a wheel to a vehicle hub which includes 
         [0007]    a wheel nut assembly for fixing a wheel to a vehicle hub which includes a wheel nut with an internal thread; 
         [0008]    a wheel stud having an external thread to co-operate with the internal thread of said wheel nut and having an end portion adapted to project beyond the wheel nut which end portion includes axial grooves or ribs on its external surface; 
         [0009]    a retaining cap for the wheel nut, said cap having internal grooves or ribs complementary to the external ribs or grooves on said wheel stud adapted to fit over said wheel stud and secure said wheel nut; 
         [0010]    and means to secure the retaining cap to said wheel nut. 
         [0011]    In this arrangement the retaining cap prevents rotation of the nut once it has been tightened. In some embodiments an aesthetic cover is provided to improve the appearance of the wheel. This aesthetic cover may also be used to lock the retaining cap to the nut and provide an indication that the nut is securely fastened. 
         [0012]    Any suitable means may be provided to secure the retaining cap to the nut. 
         [0013]    Preferably the cap consists of two components which are lockable together, one component engaging the nut and the second component engaging the end of the stud. 
         [0014]    In a preferred embodiment a ratchet mechanism is used to secure the nut. In this embodiment there is provided a wheel nut assembly for fixing a wheel to a vehicle hub which includes 
         [0015]    a wheel nut with an internal thread and an axially extending cylindrical wall extending above the nut; 
         [0016]    a wheel stud having an external thread to co-operate with the internal thread of said wheel nut and having an end portion adapted to project beyond the wheel nut into the space defined by the axially extending cylindrical wall the end portion of said stud includes axial ribs on its external surface; 
         [0017]    a nut retaining mechanism which includes a ratchet arm resiliently urged against said ribs on said stud and an unlocking mechanism associated with said ratchet arm to disengage said ratchet arm from the ribs of said stud. 
         [0018]    Preferably the unlocking mechanism requires pressure to be applied against the force of a spring and rotation to a position that disengages the ratchet arm from the ribs of the stud to enable the nut to be turned for removal. 
     
    
     
       DETAILED DESCRIPTION OF THE INVENTION 
         [0019]    Various embodiments of the invention will be described with reference to the drawings in which 
           [0020]      FIG. 1  illustrates a cross sectional view of the latched position of a first embodiment; 
           [0021]      FIG. 2  illustrates a cross sectional view of the unlatched position of the embodiment of  FIG. 1 ; 
           [0022]      FIG. 3  illustrates a cross sectional view of the latched position of a second embodiment; 
           [0023]      FIG. 4  illustrates a cross sectional view of the unlatched position of the embodiment of  FIG. 3 ; 
           [0024]      FIG. 5  is an exploded view of the embodiment of  FIGS. 2 and 3 ; 
           [0025]      FIG. 6  illustrates a cross sectional view of the latched position of a third embodiment; 
           [0026]      FIG. 7  illustrates a cross sectional view of the unlatched position of the embodiment of  FIG. 63 ; 
           [0027]      FIG. 8  is an exploded view of the embodiment of  FIGS. 6 and 7 ; 
           [0028]      FIG. 9  illustrates a cross sectional view of the latched position of a fourth embodiment; 
           [0029]      FIG. 10  illustrates a cross sectional view of the unlatched position of the embodiment of  FIG. 9 ; 
           [0030]      FIG. 11  is an exploded view of the embodiment of  FIGS. 9 and 10 ; 
           [0031]      FIG. 12  illustrates a cross sectional view of the latched position of a fifth embodiment; 
           [0032]      FIG. 13  illustrates a cross sectional view of the tool unlatching and the unlatched position of the embodiment of  FIG. 12 ; 
           [0033]      FIG. 14  is an exploded view of the embodiment of  FIGS. 12 and 13 ; 
           [0034]      FIG. 15  illustrates a cross sectional view of the latched position of a sixth embodiment; 
           [0035]      FIG. 16  illustrates a cross sectional view of the unlatched position of the embodiment of  FIG. 15 ; 
           [0036]      FIG. 17  is an exploded view of the embodiment of  FIGS. 15 and 16 ; 
           [0037]      FIG. 18  illustrates a cross sectional view of the latched position of a seventh embodiment; 
           [0038]      FIG. 19  illustrates a cross sectional view of the unlatched position of the embodiment of  FIG. 18 ; 
           [0039]      FIG. 20  is an exploded view of the embodiment of  FIGS. 18 and 19 ; 
           [0040]      FIG. 21  illustrates a cross sectional view of the latched position of an eighth embodiment; 
           [0041]      FIG. 22  illustrates a cross sectional view of the unlatched position of the embodiment of  FIG. 21 ; 
           [0042]      FIG. 23  is an exploded view of the embodiment of  FIGS. 21 and 22 ; 
           [0043]      FIG. 24  illustrates a crosssectional view of a ninth embodiment; 
           [0044]      FIG. 25  is an exploded view of the components of the  FIG. 24  embodiment 
           [0045]      FIG. 26  is a view of a tenth embodiment; 
           [0046]      FIG. 27  is an exploded view of the componentsof the embodiment of  FIG. 26 ; 
           [0047]      FIGS. 28 to 30  illustrate the operation of the embodiment of  FIG. 26 ; 
           [0048]      FIG. 31  is an exploded view of the components of an eleventh embodiment; 
           [0049]      FIGS. 32 and 33  illustrate the operation of the embodiment of  FIG. 31 . 
       
    
    
       [0050]    In all embodiments the wheel hub  1  is secured to the alloy wheel rim  2  by the stud  3  and its associated wheel nut  6 . The stud  3  has helical threads  4  that cooperate with corresponding threads  7  on the Internal surface of nut  6 . The stud  3  extends beyond the nut  6  and on this portion gas splines  5 . The retainer cap  8  fits over the nut  6  and snugly to the upper portion of the stud  3 . The upper portion of the retaining cap  8  Includes grooves  9  corresponding to the splines  5  of stud  3 . 
         [0051]    In the embodiment of  FIGS. 1 and 2  the retaining cap  8  is biased against the nut  6  by a spring  11  and is pressed downwards by the action of the cover  12  which itself is biased against cap  8  by a spring  13 , the cover  12  includes an opening  14  shaped to cooperate with a cross member  15  in the stud  3 . Rotation of the cover  12  when it is pressed down locks it onto the cross member  15 . A colour panel  16  on the retaining cap  8  indicates tat the cap is not locked if it is visible. 
         [0052]    In the second embodiment of  FIGS. 3 to 5  the retaining cap  8  is surrounded by a cylindrical cover  21  and includes recesses  22  to accommodate spring biased blocks  23  which engage stud  3  below the splines  5  when they are locked in position by the cover  21 . This arrangement is suitable where there is a fixed extension of the stud. 
         [0053]    In the third embodiment of  FIGS. 6 to 8  the stud  3  has a hollow stem  31  at its remote end which includes a spring biased core  32  with a groove 33  for engaging a ball  34  that seats within a hole  35  in the upper wall of the stud. The upper portion of the retaining cap  8  includes a groove  36  that also engages the ball  34 . An external spring  37  biasses the cap  8  away from the nut  6 . This is a compact design.  FIGS. 9 to 11  illustrate a fourth embodiment utilising a push pull arrangement. The retaining cap radial grooves 4 l for balls  42  that engage a grooved recess  43  in the upper part of stud  3 . Two pins  44  arranged concentrically with stud  3  bias the balls  42 . A cover  45  encloses the retaining cap  8 . Rotation of the cover  45  locks the cover an d retaining ca against the bias of spring  46  located at the upper end of cap  8  and against the top of cover  45 . The spring  47  acts between the wheel rim  2  and the cap  8 . 
         [0054]    Another mechanism is illustrated in a fifth embodiment which uses a tool to unlock the retaining cap as shown in  FIGS. 12-14 . A C clip  52  is inserted from below in to the retaining cap  8  and is stopped from rotating by a spring pin  53 . The C clip  52  engages grooves in the splined portion of the stud  3 . A spring  56  is placed externally of the cap  8  between flange  55  and the rim  2 . The tool  57  releases C clip to unlock the assembly. 
         [0055]    The sixth embodiment illustrated in  FIGS. 15-17  uses a custom nut with recesses  61  in its corners to engage balls  62  carried in holes  63  of the retaining cap  8 . A cover  64  has associated spring plugs  65  that are inserted in radial holes in the retaining cap. 
         [0056]    The seventh embodiment shown in  FIGS. 18-20  uses a spring loaded pin  71  arranged in a passage  72  in the retaining cap  8  that pushes a ball  73  into engagement with a groove  74  in the splined end of the stud  3 . A spring  76  is placed externally of the cap  8  between flange  75  and the rim  2 . 
         [0057]      FIGS. 21-23  illustrate an eighth embodiment that utilises a custom nut design with a cut out portion  81  to accept a plug  82  for locking. The cap  8  also has a cut out  83  corresponding with that in the nut  6 . A cylindrical cover  86  seats under flange  85  of cap  8 . A spring retaining pin  87  may be used to secure the cover  86  to cap  8 . 
         [0058]    In the ninth embodiment shown in  FIGS. 24 and 25  a custom nut  6  is used which has recesses  91  for the balls  92 . The balls  92  sit in holes  93  in the side wall of the retaining cap  8 . A spring  94  is located internally of the cap  8  to bias the cap  8  away from nut  6 . A cylindrical cover  95  encloses the retaining cap  8 . A spring  98  seats on the outside of the upper portion of the cap  8  to bear against the clutch ring  97  that lies underneath the top of cover  95 . A key  98  is used to depress and turn the clutch ring  97  so that the cover  95  is locked to the cap  8 . An O ring  99  provides a seal between lower edge of the cover  95  and the lower edge of the cap  8 . The clutch ring  97  provides a seal at the top to prevent dirt entering under cover  95 . The cover  8  may carry a decorative cover  100 . 
         [0059]    In the tenth embodiment shown in  FIGS. 26-30  the nut  6  and custom stud  3  are the same. The nut includes recesses  119  for locking balls  110 . The cap or socket lock  8  seats around the nut and the ejector spring  111  sits within cap  8  on top of the nut  6 . The out surface of the cap or socket lock includes splines or ribs  120 . The spline lock  113  engages the splines on the end of stud  3  and also engages the spline  120  of cap  8 . The nut spring  112  lies between the spline lock  113  and the cap  8 . On top of the spline lock is a disc  115  that sits on the lock spring  114  which is held within the spline lock  113 . The rotary lock  116  extends over the disc  115  and the spring  114  to abut an outer rim of the spline lock  113 . The cover  117  encloses all the components including the locking balls  110  which are held in holes in the wall of cap  8  as best seen in  FIGS. 28-30 . 
         [0060]    The ratio of the faces on the nut  6  and the splines on the stud  3  and the splines  120  on cap  8  ensure that only a slight turning of the assembly is needed as it is pressed down to align the faces and splines. 
         [0061]    The assembled wheel lock is fitted as shown in  FIGS. 28-30 . In  FIG. 28  the assembly sits on the tightened nut  6 . In  FIG. 29  the assembly has been pushed down to compress the ejector spring  111 . As the assembly is pushed don itis turned slightly so that the internal hexagon faces of cap  8  engages the faces of wheel nut  6  and the locking balls are held in the recesses  119  of the nut  6 . In  FIG. 30  the assembly is pushed down further and again turned slightly so that the spline lock  113  engages the splines on the end of stud  3  and splines  120  on cap  8 . The socket lock or cap  8  now engages with the spline lock  113  and the balls  110  are locked into the recesses  119  on nut  6 . Using the key  118  the rotary lock  116  is turned which locks the entire assembly together and to the stud and nut. 
         [0062]      FIGS. 31 to 33  illustrate an eleventh embodiment which uses a ratchet mechanism to secure the retaining cap to the wheel nut and provides a visual indication of the lock status of the wheel nut. The stud  3  is the same as in prior embodiments. The nut  121  includes a circumferential cover extending above the nut to accommodate the ratchet locking mechanism. The custom screws 128  secure the ratchet sleeve  124  to the nut  121 . 
         [0063]    The ratchet mechanism consists of pawls  125  that engage with the splines on the end of stud  3  when biased by the spring  126 . The ring  127  holds the pawls  125  and spring  126  in position. The spring  129  seats on the ring  127  and the O rings  130  and  131  are positioned above and below the ratchet sleeve  124 . The knob 132  engages with the internal rim of the ratchet sleeve  124 . 
         [0064]    In  FIG. 32  view A shows that as the nut is tightened the pawls engage the the spline and prevent the nut from coming loose. View B provides a detailed view and view C is a section view along z-z of view A. 
         [0065]      FIG. 33  illustrates the removal of the nut. In view A the knob  132  is pushed down and rotated a quarter turn in direction A . View B provides a detailed view and view C is a section view along z-z of view A. The top assembly is retained by the 3 screws  128  engaging in the bayonet guides in ratchet sleeve  124 . The top assembly is under constant tension by spring  129 . The top assembly disengages the pawls  125  from the splines on stud  3  and the nut can be removed by rotation in direction B of view A. 
         [0066]    Those skilled in the art will realise that this invention provides a unique and less expensive means of ensuring that a wheel nut is securely fastened to the wheel hub. Those skilled in the art will also realise that this invention may be implemented in embodiments other than those described without departing from the core teachings of the invention.