Abstract:
A dual axis bushing assembly for engagement between an axle arm and an upper ball joint of a vehicle. The dual axis bushing assembly includes an inner skewed bushing engaged in and rotatable in an outer skewed bushing. The dual axis bushing assembly includes a zero offset setting or a zero skewed setting where a skewed axis of the inner bushing is coaxial with a center axis of an outer cylindrical surface of the outer bushing. At the zero setting, a connector seating annular surface on the inner skewed bushing is disposed at a right angle relative to a cylindrical outer surface of the outer skewed bushing. In one embodiment, the connector seating annular surface is recessed in a head of the inner skewed bushing. In another embodiment, the connector seating annular surface is an outermost end surface of a head of the inner skewed bushing. A method of camber and caster adjustment is disclosed that eliminates each of the steps of installing a standard zero bushing, taking camber and caster readings with the standard zero bushing in place, and then removing the standard zero bushing for an after market bushing.

Description:
[0001]     This application claims the benefit under 35 U.S.C. 119(e) of U.S. Provisional Patent Application No. 60/580,231 filed Jun. 16, 2004. Such provisional application is hereby incorporated by reference in its entirety into this application. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to a bushing assembly having an outer bushing and an inner bushing engaged and rotatable relative to each other, particularly to such a rotatable bushing assembly where each of the bushings includes a skewed through opening, and specifically to such a rotatable and dual skewed bushing assembly installed between an axle arm and upper ball joint of a vehicle.  
       BACKGROUND OF THE INVENTION  
       [0003]     A wheel is mounted on a spindle or steering knuckle. The spindle or steering knuckle includes support arms or extensions or portions for the reception of upper and lower ball joint assemblies. A ball joint is a ball and socket connection, and a ball stud extends from the ball portion of the ball joint.  
         [0004]     An axle arm assembly, such as an I-beam axle arm assembly, includes a first or inner end anchored to the frame of the vehicle and a second or outer end supported by a coil spring and a radius arm. The second end is further engaged to the wheel by the upper and lower ball joint assemblies.  
         [0005]     An upper portion of the second end of the axle arm assembly engages the stud of the ball of the upper ball joint. By manipulating the orientation of the upper portion of the second end of the axle arm relative to the stud of the ball of the ball joint, certain positions of the wheel relative to the frame of the vehicle may be adjusted. These certain positions are camber and caster.  
         [0006]     Upper and lower steering pivot points, such as upper and lower ball joints, help define a caster angle. The upper and lower steering pivot points can be 1) the upper and lower ball joints of a wishbone suspension design, 2) the upper and lower ball joints of an A-arm suspension design, or 3) the lower ball joint and the strut tower mount of a McPherson strut design.  
         [0007]     The caster or caster angle is the slope of a straight line running through the upper and lower steering pivot points relative to a vertical line running perpendicular to the ground and through the center point of the tire, when viewed from the side of the vehicle. Caster is a backward or forward tilt of a kingpin, ball joint, or strut at the top of the wheel assembly. A backward tilting is referred to as positive caster. A forward tilting is referred to as negative caster. Caster is a directional control angle or steering angle, not a tire wearing angle. Proper adjustment of the caster angle helps the front wheels maintain a straight ahead position or return to a straight ahead position out of a turn. Positive caster (a tilting back) places the point of load ahead of the wheel contact. Depending upon the vehicle, either positive or negative caster may be desired.  
         [0008]     Camber is a tire-wearing angle. Camber, like caster, is a directional control angle. The camber or camber angle is the tilting of a front wheel relative to the vertical when viewed from the front of the vehicle. More specifically, camber is the inward or outward tilt of the wheel at the top relative to the ground or true vertical. Positive camber is the angle of the outward tilt relative to true vertical. Negative camber is the angle of the inward tilt relative to true vertical. By properly adjusting the camber angle, then 1) the road contact of the tire is brought more nearly under the point of load, and 2) easier steering is provided by allowing the weight of the vehicle to be carried by the inner wheel bearing and spindle.  
         [0009]     One method of caster and camber adjustment includes the steps of removing the original or first bushing, temporarily installing a standard zero offset or second bushing, taking camber and caster readings with the temporary installed, standard zero offset or second bushing in place, removing the standard zero offset or second bushing, and then installing an after market or third bushing.  
       SUMMARY OF THE INVENTION  
       [0010]     A feature of the present invention is the provision in a dual axis bushing assembly, of an inner skewed bushing engaged in and rotatable in an outer skewed bushing, of the inner and outer skewed bushings being rotatable relative to each other such that a skewed axis of the inner skewed bushing is coaxial with an axis of the outer skewed bushing and such that the skewed axis of the inner skewed bushing is at a geometric center axis of the dual axis bushing assembly as a whole.  
         [0011]     Another feature of the present invention is the provision in a dual axis bushing assembly having an inner skewed bushing engaged in and rotatable in an outer skewed bushing, of the bushing assembly engaged between an axle arm and an upper ball joint of a vehicle.  
         [0012]     Another feature of the present invention is the provision in a dual axis bushing assembly having an inner skewed bushing engaged in and rotatable in an outer skewed bushing, of the inner skewed bushing having a head that includes a connector seating annular surface recessed therein for seating, for example, a snap ring.  
         [0013]     Another feature of the present invention is the provision in a dual axis bushing assembly having an inner skewed bushing engaged in and rotatable in an outer skewed bushing, of each of the inner and outer skewed bushings including a head, of the heads rotatably confronting each other, of each of the heads being tapered to have a relatively thick portion relative to an axis of the bushing assembly and a relatively thin portion relative to the axis of the bushing assembly, and of the head of the inner skewed bushing including an outermost end annular surface comprising a connector seating annular surface for seating, for example, a castle nut.  
         [0014]     Another feature of the present invention is the provision in a dual axis bushing assembly having an inner skewed bushing engaged in and rotatable in an outer skewed bushing, of the inner skewed bushing having a connector seating annular surface, and of the outer skewed bushing having a cylindrical outer surface portion that can be disposed at a right angle to the connector seating annular surface when the inner and outer skewed bushings are rotated relative to each other.  
         [0015]     Another feature of the present invention is the provision in a dual axis bushing assembly having an inner bushing engaged in and rotatable in an outer bushing, of the outer bushing being skewed such that a through opening in the outer bushing is skewed relative to an outer surface cylindrical portion of the outer bushing.  
         [0016]     Another feature of the present invention is the provision in a dual axis bushing assembly having an inner bushing engaged in and rotatable in an outer bushing, of the outer bushing including inner and outer annular seats, and of the inner bushing including inner and outer annular seats for engaging the respective inner and outer annular seats of the outer bushing whereby a stepped engagement is provided between the outer and inner bushings to minimize entry of dirt and moisture therebetween and whereby a head of a relatively greater height can be provided to the inner bushing.  
         [0017]     Another feature of the present invention is the provision in a method for camber and caster adjustment of a wheel, of removing an original bushing from an upper ball joint, of installing a dual axis bushing assembly on the upper ball joint, wherein the dual axis bushing assembly includes an inner skewed bushing engaged and rotatable in an outer skewed bushing, and wherein the dual axis bushing assembly includes a zero offset setting, of rotating the outer and inner skewed bushings relative to each other to the zero setting if not at the zero setting when the dual axis bushing assembly was installed, and of rotating the outer and inner skewed bushings relative to each other to obtain desired camber and caster settings such that the step of temporarily installing a standard zeroed bushing to take camber and caster readings is eliminated.  
         [0018]     An advantage of the present invention is accurate camber and caster settings. The present dual axis bushing assembly includes a neutral or zero offset setting. The inclusion of such a feature permits the elimination of the step of temporarily installing a standard zeroed bushing, a step that in and of itself may disturb caster and camber readings because the suspension connection train between the frame of the vehicle and the wheel is broken by removing the standard zeroed bushing and installing the after market bushing.  
         [0019]     Another advantage of the present invention is efficiency in the adjustment of camber and caster because one step, namely the step of temporarily installing a standard zeroed bushing, is eliminated.  
         [0020]     Another advantage of the present invention is simplicity. With the present dual axis bushing assembly in place on a vehicle and having the zero setting, camber and caster settings can be measured. Such camber and caster settings are usually unique, even with identical vehicles just off the assembly line. Then, taking into account the unique camber and caster settings, the inner and outer skewed bushings are rotated relative to each other and/or the bushing assembly as a whole is rotated relative to the stud of the ball joint, such that the wheel takes on the desired camber and caster settings.  
         [0021]     Another advantage of the present invention is cost. The dual axis bushing assembly having an outer skewed bushing and an inner skewed bushing is relatively inexpensive to manufacture. Further, the cost of stocking standard zeroed bushings for a number of different vehicles is eliminated.  
         [0022]     Another advantage of the present invention is that the heads of the dual axis bushing assembly are user-friendly. That is, the inner and outer bushing assemblies are structured to provide heads that are relatively thick in the axial direction and relatively large in diameter. The thicker heads provide a greater surface area for reception of the tool of the technician to thereby minimize a slipping of the tool off the bushing assembly. The larger heads provide a greater leverage and thus easier turning for the technician. Features that contribute to the greater thickness and greater diameter are, in one embodiment, the provision of a stepped engagement between the inner and outer bushings and, in another embodiment, the provision of each of the inner and outer skewed bushings having tapered heads that rotatably confront each other. 
     
    
     IN THE DRAWINGS  
       [0023]      FIG. 1  shows an exploded perspective view of a portion of a suspension of a vehicle, including an axle arm, a spindle for engaging a wheel, and one embodiment of the present dual axis bushing assembly.  
         [0024]      FIG. 2A  shows a top view of dual axis bushing assembly of  FIG. 1  in a neutral or zeroed position.  
         [0025]      FIG. 2B  shows a side view of the dual axis bushing assembly of  FIG. 2A  in a neutral or zeroed position.  
         [0026]      FIG. 2C  shows a section view at lines  2 C- 2 C of  FIG. 2A .  
         [0027]      FIG. 2D  is a detail view showing an annular retaining ridge and an annular retaining groove of the outer and inner bushings, respectively, relative to  FIG. 2C .  
         [0028]      FIG. 3A  is a section view of the outer skewed bushing of the embodiment of  FIGS. 2A and 2B .  
         [0029]      FIG. 3B  is a section view of the inner skewed bushing of the embodiment of  FIGS. 2A and 2B .  
         [0030]      FIG. 3C  is a section view of the inner and outer skewed bushings of  FIGS. 3A and 3B  rotated relative to each other to the neutral or zeroed position.  
         [0031]      FIG. 3D  is a section view of the inner and outer skewed bushings of  FIGS. 3A and 3B  rotated relative to each other to a maximum skewed setting having a maximum skew angle, in which setting the inner bushing has been rotated 180 degrees relative to the outer bushing shown in  FIG. 3C .  
         [0032]      FIG. 4  shows an exploded perspective view of a portion of a suspension of a vehicle, including an axle arm, a spindle for engaging a wheel, and another embodiment of the present dual axis bushing assembly.  
         [0033]      FIG. 5A  is a top view of a modified castle nut for the dual axis bushing assembly of  FIG. 4 .  
         [0034]      FIG. 5B  is a side view of the modified castle nut of  FIG. 5A .  
         [0035]      FIG. 5C  is a side, partially phantom view of the dual axis bushing assembly of  FIG. 4  engaged to the stud of the ball of the upper ball joint with the castle nut.  
         [0036]      FIG. 6A  shows a top view of dual axis bushing assembly of  FIG. 4  in a neutral or zeroed position.  
         [0037]      FIG. 6B  shows a side view of the dual axis bushing assembly of  FIG. 6A  in a neutral or zeroed position.  
         [0038]      FIG. 6C  shows a section view at lines  6 C- 6 C of  FIG. 6A .  
         [0039]      FIG. 6D  is a detail view showing an annular retaining ridge and an annular retaining groove of the outer and inner bushings, respectively, relative to  FIG. 6C .  
         [0040]      FIG. 7A  is a section view of the outer skewed bushing of the embodiment of  FIGS. 6A and 6B .  
         [0041]      FIG. 7B  is a section view of the inner skewed bushing of the embodiment of  FIGS. 6A and 6B .  
         [0042]      FIG. 7C  is a section view of the inner and outer skewed bushings of  FIGS. 7A and 7B  rotated relative to each other to the neutral or zeroed position.  
         [0043]      FIG. 7D  is a section view of the inner and outer skewed bushings of  FIGS. 7A and 7B  rotated relative to each other to a maximum skewed setting having a maximum skew angle, in which setting the inner bushing has been rotated 180 degrees relative to the outer bushing shown in  FIG. 7C .  
         [0044]      FIG. 8A  is a diagrammatic view of a prior art unfocused bushing assembly.  
         [0045]      FIG. 8B  is a diagrammatic view of the present single point focused bushing assembly (either the embodiment of  FIG. 1  or the embodiment of  FIG. 4 ).  
         [0046]      FIG. 9A  shows a top view of the outer bushing of  FIG. 3A .  
         [0047]      FIG. 9B  shows a top view of the inner bushing of  FIG. 3B .  
         [0048]      FIG. 9C  shows a top view of the outer bushing of  FIG. 7A .  
         [0049]      FIG. 9D  shows a top view of the inner bushing of  FIG. 7B .  
         [0050]      FIG. 10A  shows a bottom view of the bushing assembly of  FIG. 3C , illustrating the neutral position.  
         [0051]      FIG. 10B  shows a bottom view of the bushing assembly of  FIG. 7C , illustrating the neutral position.  
         [0052]      FIG. 10C  shows a bottom view of the bushing assembly of  FIG. 3D , illustrating the maximum skewed position.  
         [0053]      FIG. 10D  shows a bottom view of the bushing assembly of  FIG. 7D , illustrating the maximum skewed position. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0054]     One dual axis bushing assembly of the present invention is shown in  FIG. 1  and indicated by the reference numeral  10  and another dual axis bushing assembly of the present invention is shown in  FIG. 4  and indicated by the reference numeral  12 . Each of the assemblies  10 ,  12  includes an inner skewed bushing engaged in and rotatable in an outer skewed bushing.  
         [0055]     As shown in  FIG. 1 , bushing assembly  10  provides a camber and caster connection between a spindle  14  and an axle arm  16 . Spindle  14  includes an outward extension  18  upon which a wheel is mounted and an inward extension  20  for mounting an upper ball joint  22  having a stud  24  extending from the ball of the ball joint  22 . Axle arm  16  includes an inner end portion  26  mounted to the frame of a vehicle and an outer end portion  28 . Outer end portion  28  includes an upper control arm  30  having a cylindrical opening  32  that may be increased or decreased in diameter via a pinch clamp  34  tightened or loosened with a pinch bolt  36 . Opposing end portions of the pinch clamp  34  confront each other at a generally linear location  38  that can be used during a camber and caster alignment operation. Bushing assembly  10  further includes a snap ring  40  that contributes to the engagement of assembly  10  between the spindle  14  and axle arm  16  and specifically engages a groove in the distal or upper or free end of the stud  24  of the upper ball joint  22  and, when so engaged, is also seated within the assembly  10 .  
         [0056]      FIGS. 2A, 2B ,  2 C,  2 D,  3 A,  3 B,  3 C, and  3 D show assembly  10  in detail. Assembly  10  includes an outer skewed bushing  42 , shown alone in  FIG. 3A , and an inner skewed bushing  44 , shown alone in  FIG. 3B . Outer skewed bushing  42  generally includes an outer cylindrical surface portion  46 , a head  48  and a through opening  50 .  
         [0057]     Outer cylindrical surface portion  46  has a central axis A. Through opening  50  is defined in part by an inner cylindrical surface portion  52 , which has a central axis B. Through opening  50  is further defined in part by an inner cylindrical surface portion  54 , which also has axis B as a central axis. Axis B is skewed relative to axis A such that through opening  50  is skewed relative to outer surface cylindrical portion  46 .  
         [0058]     Inner cylindrical surface portion  54  has a greater diameter than inner cylindrical surface portion  52  and, between such portions  52 ,  54 , is formed an annular seat  56  for receiving a seat of the inner skewed bushing  44 . Annular seat  56  lies in a plane that is 1) positioned at a right angle relative to axis B, 2) positioned obliquely relative to axis A, and 3) positioned obliquely relative to outer surface cylindrical portion  46 .  
         [0059]     Inner cylindrical surface portion  52  is broken by an annular retaining ridge or barb  57 . Annular retaining ridge or barb  57  lies in a plane that is parallel to the plane in which annular seat  56  lies and hence barb  57  lies in a plane that is 1) positioned at a right angle relative to axis B, 2) positioned obliquely relative to axis A, and 3) positioned obliquely relative to outer surface cylindrical portion  46 . Annular barb  57  is a lock that permits inner skewed bushing  44  to be slid into opening  50 , over barb  57 , and locked thereto, thereby minimizing chances for an unintended removal of inner skewed bushing  44  from outer skewed bushing  42 .  
         [0060]     Outer skewed bushing  42  includes a first or lower annular end or surface  58  and a second or upper annular end or surface or seat  60 . Surface  58  lies in a plane disposed at a right angle relative to axis A. Surface  60  lies in a plane disposed at a right angle to axis B and hence lies in a plane that is parallel to annular seat  56  and annular barb  57 . Surface  60  is an annular seat for receiving a seat of the inner skewed bushing  44 .  
         [0061]     Head  48  of outer skewed bushing  42  has a width greater than a width of the outer surface cylindrical portion  46 . Head  48  is defined in part by annular surface or seat  60 . Head  48  is further defined in part by annular surface  62 . Surface  62  lies in a plane that is positioned at a right angle to axis A and obliquely to axis B. Head  48  is further defined in part by polygonal surface  64  running between surfaces  60  and  62 . Polygonal surface  64  is best shown in  FIG. 2A . Polygonal surface  64  preferably is hexagonal for engagement by a tool such as a socket wrench such that the outer skewed bushing  42  can be turned or dialed relative to the inner skewed bushing  44 . Head  48  is tapered. That is, annular surface  60  runs obliquely relative to axis A and annular surface  62  runs at a right angle relative to axis A such that head  48  includes a relatively thick portion  66  that diametrically opposes a relatively thin portion  68 , where the relative thickness and thinness is defined as a distance running along axis A.  
         [0062]     Outer skew bushing  42  further includes a through slot  70  extending from outer cylindrical surface portion  46  to inner cylindrical surface portion  52 , from polygonal surface  64  to inner cylindrical surface portion  54 , and from annular end or surface  58  to annular end or surface  60 . Slot  70  is parallel to axis A and is shown in  FIGS. 2A and 2B . During a camber and caster alignment procedure or method, one alphabetical indicia of inner skewed bushing  44  is preferably aligned with slot  70  by rotating bushings  42 ,  44  relative to each other. Then bushing assembly  10  is rotated as a whole and at this time another alphabetical indicia (or perhaps the same alphabetical indicia or perhaps the slot  70 ) of inner skewed bushing  44  serves as an alignment or reference marking, such as relative to a marking on pinch clamp  34  or disposed adjacent to generally linear mark  38  shown in  FIG. 1 . Slot  70  further permits the outer skewed bushing  42  to be squeezed tightly against inner skewed bushing  44  when pinch bolt  36  draws the opposing portions or jaws of the pinch clamp  34  together.  
         [0063]     As shown in  FIG. 3B , inner skewed bushing  44  includes an outer cylindrical surface portion  72 , a head  74 , and a through opening  76 . Outer cylindrical surface portion  72  has a central axis C. Through opening  76  is defined in part by an inner cylindrical surface portion  78 , which has a central axis D. Through opening  76  is further defined in part by an inner cylindrical surface portion  80 , which also has axis D as a central axis. Axis D is skewed relative to axis C such that through opening  76  is skewed relative to outer surface cylindrical portion  72 . Outer cylindrical surface portion  72  of inner skewed bushing  44  has a diameter equal to or slightly greater than the inner cylindrical surface portion  52  of outer skewed bushing  42  such that the inner skewed bushing  44  is engaged relatively tightly in the outer skewed bushing  42  so as to minimize, if not prevent, rotation by hand, and permit rotation only with the aid of leverage, such as leverage provided by a pair of wrenches, where one wrench engages bushing  42  and the other wrench engages bushing  44 .  
         [0064]     Inner cylindrical surface portion  80  has a greater diameter than inner cylindrical surface portion  78  and, between such portions  78 ,  80  is formed a connector seating annular surface  82  for receiving snap ring  40 . Connector seating annular surface  82  lies in a plane that is 1) positioned at a right angle relative to axis D, 2) positioned obliquely relative to axis C, and 3) positioned obliquely relative to outer surface cylindrical portion  72 . Indicia  84 , namely alphabetical indicia, is formed in surface  82  for incrementally dialing inner skewed bushing  44  to the desired position relative to outer skewed bushing  42 . Preferably, one alphabetical indicia  84  is rotatably aligned with slot  70  to provide the desired skew angle relative to outer cylindrical surface portion  46  of the outer skewed bushing  42 . Then, bushing assembly  10  is preferably as a whole rotated to align another alphabetical indicia  84  (or perhaps the same alphabetical indicia or perhaps slot  70 ) with linear marking  38  (or another marking) to provide the desired skew angle relative to stud  24  and axle arm  16 , thereby providing the desired camber and caster angles to the wheel. Then pinch bolt  36  is engaged and torqued. Then snap ring  40  is engaged to the ball stud  24  and, in such position, is preferably seated on the connector seating annular surface  82 . In such a position, snap ring  40  covers indicia  84  and is shielded, via head  74 , from rocks thrown into the suspension area by the wheel or from inadvertent or errant outside forces such as crowbars, jacks and other tools used on vehicles. Loss of the snap ring  40  leaves the pinch clamp  34  and pinch bolt  36  as the sole means of connection between the upper ball joint  22  and the upper control arm  30 .  
         [0065]     Outer cylindrical surface portion  72  includes an annular retaining groove  86  formed therein for engaging annular barb  57 . Annular retaining groove  86  lies in a plane that is 1) positioned at a right angle relative to axis C, 2) positioned obliquely relative to axis D, and 3) positioned at a right angle relative to outer surface cylindrical portion  72 . Annular barb  57  locks into groove  86  and permits inner skewed bushing  44  to be slid into opening  50  and over barb  57  whereupon, upon attempted removal of inner skewed bushing  44  from outer skewed bushing  42 , the right angled wall of barb  57  confronts the lower right angled wall of groove  86 .  
         [0066]     Inner skewed bushing  44  includes a first or lower annular end or surface  88  and a second or upper annular end or surface  90 . Surface  88  lies in a plane disposed at a right angle relative to axis C. Surface  88 , when inner skewed bushing  44  is engaged to outer skewed bushing  42 , lies within through opening  50  of outer skewed bushing  42  and does not extend beyond annular end  58  of outer skewed bushing  42 . Annular surface  90  lies in a plane disposed at a right angle relative to axis C.  
         [0067]     Head  74  of inner skewed bushing  44  includes a first or outer annular head portion  92  and a second or inner annular head portion  94 . Outer annular head portion  92  has a width greater than a width of the inner annular head portion  94 , which in turn has a width greater than outer surface cylindrical portion  72 . Outer annular head portion  92  is defined in part by outer annular surface  90 , and is further defined in part by an annular seat  96  that rides on annular surface or seat  60  of the head  48  of outer skewed bushing  42 . Inner annular seat  94  is defined in part by an annular seat  98  that rides on annular seat  56  of the head  48  of the outer skewed bushing  42 . Outer annular head portion  92  is further defined in part by a polygonal sidewall or surface  100 , best shown in  FIG. 2A . Polygonal surface  100  preferably is hexagonal for engagement by a tool such as a socket wrench such that the inner skewed bushing  44  can be turned or dialed relative to the outer skewed bushing  42 . Inner annular seat  94  is further defined in part by an annular sidewall or surface  102  that includes a diameter equal to or slightly greater than the diameter provided by inner annular surface portion  54  of the outer skewed bushing  42 . Head portions  92 ,  94  and corresponding surfaces  96 ,  94 ,  98  on inner skewed bushing  44  and head  48  and corresponding surfaces  54  and  56  provide a stepped engagement, or double seated engagement, between the outer and inner skewed bushings  42 ,  44 . Such a stepped engagement minimizes entry of moisture and dirt to positions between the outer and inner skewed bushings  42 ,  44 . Such a stepped engagement further permits head  74  to have a greater diameter for the tool turning polygonal sidewall  100  and still further permits the head  74  to have a greater height or thickness along axis D to provide more surface area on the polygonal sidewall  100  for confronting the tool or wrench engaging the polygonal sidewall  100 .  
         [0068]     Annular surface  96  lies in a plane that is positioned at a right angle to axis C. Annular surface  98  lies in a plane that is positioned at a right angle to axis C.  
         [0069]     Connector seat receiving surface  82  lies in a plane positioned at a right angle relative to axis D. Connector seat receiving surface  82  and inner cylindrical surface portion  80  form a recess  104  for receiving snap ring  40 . Recess  104 , via head  74 , provides a protected or shielded or safe area for the snap ring  40 . In section, recess  104  is tapered in shape.  
         [0070]     Inner skew bushing  44  further includes a through slot  106  extending from outer surfaces  72 ,  94  and  92  to inner surfaces  78  and  80  and further extending from annular end  88  to annular end  90  such that through slot  106  extends entirely through the wall of the inner skew bushing  44 . Slot  106  is parallel to axis C and is shown in  FIGS. 2A, 2C ,  3 B, and  3 C. During a camber and caster alignment procedure or method, slot  106  is typically not used. Slot  106  permits the inner skewed bushing  44  to be squeezed tightly against the stud  24  of the upper ball joint  22  when pinch bolt  36  draws the opposing portions or jaws of the pinch clamp  34  together.  
         [0071]      FIG. 3C  shows that, when inner skewed bushing  44  is engaged in outer skewed bushing  42  and rotated to what is defined as a neutral or zeroed position, axis A and axis D are aligned. There is only one such neutral or zeroed position, and in such position axis A and axis D overlay each other as well as being aligned with one another. At such a position, bushing assembly  10  as a whole acts like a one-piece bushing having no skew and no eccentricity, where eccentricity is defined as a bushing having an axis located elsewhere than at the geometric center. In other words, at the neutral or zeroed position, axis D of through opening  76 , which confronts the stud  24  of the upper ball joint  22 , is a central axis relative to the outer cylindrical surface portion  46  of the outer skewed bushing  42 , which is confronted by the jaws of the pinch clamp  34 .  
         [0072]      FIGS. 3C and 3D  shows that axis B is always aligned with and overlaid by axis C because axis B is the central axis of the through opening  50 , which receives the outer cylindrical surface portion  72 , which in turn has central axis C. From an operational standpoint, axis B and axis C are one and the same and may be referred to as axis BC.  
         [0073]      FIG. 3D  shows a maximum skew angle for through opening  76 , which confronts the stud  24  of the upper ball joint  22 , relative to the outer cylindrical surface portion  46 , which is confronted by the jaws of the pinch clamp  34 . In other words, central axis D of through opening  76  of inner skew bushing  44  is disposed at a maximum angle relative to central axis A of the outer cylindrical surface portion  46  of outer skew bushing  42 . It should be noted that, at all rotative positions except the neutral or zeroed position, axis A, axis D and axis BC intersect at only one point. This single point is disposed within through opening  76  such that the single point is disposed within the bushing assembly  10  as a whole.  
         [0074]     It should be noted that incremental and intermediate angles of skew are obtained by rotating the outer and inner skewed bushings  42 ,  44  to positions other than that shown in  FIGS. 3C and 3D . After the desired angle of skew is obtained, whether such skew angle is that shown in  FIG. 3C , is that shown in  FIG. 3D , or is an intermediate scew angle therebetween, such a desired angle is further exploited by rotating the bushing assembly  10  as a whole in opening  32  of pinch clamp  34  to obtain the desired caster and camber angles.  
         [0075]     By comparing  FIGS. 9A and 10A , it should be noted that through opening  50  is relatively greatly eccentric relative to end surface  58  and relatively minimally eccentric relative to end surface  60 . By comparing  FIGS. 9B and 10A , it should be noted that through opening  76  is relatively greatly eccentric relative to end surface  88  and is relatively minimally eccentric relative to end surface  90 . Such minimal eccentricity is a further feature that permits a greater diameter and greater thickness to each of heads  48  and  74 . Such minimal eccentricity can also be seen in section views  3 A and  3 B.  
         [0076]     As shown in  FIG. 4 , bushing assembly  12  provides a camber and caster connection between a spindle  110  and an axle arm  112 . Spindle  110  includes outward extensions  114  upon which a wheel is mounted and an inward extension  116  for mounting an upper ball joint  118  having a tapered, threaded and apertured stud  120  extending from the ball of the ball joint  118 . Axle arm  112  includes an inner end portion  122  mounted to the frame of a vehicle and an outer end portion  124 . Outer end portion  124  includes an upper control arm or portion  126  having a cylindrical opening  128  for receiving the bushing assembly  12 . Bushing assembly  12  is engaged in opening  128  via a castle nut  130  threaded onto the threaded stud  120 . A cotter pin  132  extends through an aperture in the stud  120  and further extends through slots of the caste nut  130  to minimize unintended turning, and hence ultimate disengagement, of castle nut  130 .  
         [0077]      FIGS. 5A, 5B  and  5 C show the castle nut  130  in detail. Castle nut  130  is a unique castle nut  130  where the uniqueness is provided by the length of open ended slots  134 , where each of the open ended slots includes a floor  136 . In other words, each of slots  134  includes a length greater than one-half the height of the castle nut  130 . The phantom lines shown in  FIG. 5B  show a conventional height for the floors of the slots of a conventional castle nut. Castle nut  130  includes an inner threaded opening  138  and an outer polygonal surface portion  140  for being manipulated by a wrench or other tool. With a lower floor  136 , castle nut  130  can ride at a greater height on the stud  120 , which in turn permits bushing assembly  12  as a whole to have a greater axial height and the head or head portions of the bushing assembly  12  to have a greater axial height (or thickness).  
         [0078]      FIGS. 6A, 6B ,  6 C,  6 D,  7 A,  7 B,  7 C, and  7 D show bushing assembly  12  in detail. Bushing assembly  12  includes an outer skewed bushing  142 , shown alone in  FIG. 7A , and an inner skewed bushing  144 , shown alone in  FIG. 7B . Outer skewed bushing  142  generally includes an outer cylindrical surface portion  146 , a head  148  and a through opening  150 .  
         [0079]     Outer cylindrical surface portion  146  has a central axis A′. Through opening  150  is defined by an inner cylindrical surface portion  152 , which has a central axis B′. Axis B′ is skewed relative to axis A′ such that through opening  150  is skewed relative to outer surface cylindrical portion  146 .  
         [0080]     Inner cylindrical surface portion  152  is broken by an annular retaining ridge or barb  157 . Annular retaining ridge or barb  157  lies in a plane that is 1) positioned at a right angle relative to axis B′, 2) positioned obliquely relative to axis A′, and 3) positioned obliquely relative to outer surface cylindrical portion  146 . Annular barb  157  is a lock that permits inner skewed bushing  144  to be slid into opening  150 , over barb  157 , and locked thereto, thereby minimizing chances for an unintended removal of inner skewed bushing  144  from outer skewed bushing  142 .  
         [0081]     Outer skewed bushing  142  includes a first or lower annular end or surface  158  and a second or upper annular end or surface or seat  160 . Surface  158  generally lies in a plane disposed at a right angle relative to axis A′. One portion, identified by reference numeral  159 , may be slightly recessed in the axial direction, to avoid the provision of an excessively thin wall section. Surface  160  lies in a plane disposed at a right angle to axis B′ and hence lies in a plane that is parallel to barb  157 . Surface  160  is an annular seat for receiving a seat of the inner skewed bushing  144 .  
         [0082]     Head  148  of outer skewed bushing  142  has a width, defined as the distance between outer ends of knuckles or ribs or ears or dogs  165 , greater than a width of the outer surface cylindrical portion  146 . Head  148  is defined in part by annular surface or seat  160 . Head  148  is further defined in part by annular surfaces  162 , which are the undersides of knuckles  165 . Surfaces  162  lie in a plane that is positioned at a right angle to axis A′ and obliquely to axis B′. Head  148  is further defined in part by surfaces  164  running between surfaces  160  and  162 . Surfaces  164  are the outer sides of knuckles or extensions  165 , best shown in  FIG. 6A . Knuckles  165  can be engaged by a tool such that the outer skewed bushing  142  can be turned or dialed relative to the inner skewed bushing  144 . Head  148  is further defined by a cylindrical surface portion  167  that extends between knuckles  165 . Cylindrical surface portion  167  is effectively an extension of, or forms part of, outer cylindrical surface portion  146 .  
         [0083]     Head  148  is tapered. That is, annular surface  160  lies in a plane that runs obliquely relative to axis A′ and annular surfaces  162  (the lower sides of the knuckles  165 ) lie in a plane that runs at a right angle relative to axis A′ such that head  148  includes a relatively thick portion  166  having a relatively thick knuckle  165  that diametrically opposes a relatively thin portion  168  having a relatively thin knuckle  165 , where the relative thickness and thinness is defined as a distance running along axis A′. Knuckles  165  too are tapered in a like manner.  
         [0084]     Outer skew bushing  142  further includes a through slot  170  extending from outer cylindrical surface portion  146  to inner cylindrical surface portion  152  and further extending from annular end or surface  158  to annular end or surface  160 . Slot  170  is parallel to axis A′ and is shown in  FIGS. 6A and 6B . During a camber and caster alignment procedure or method, inner bushing  144  is rotated relative to outer bushing  142  to align one alphabetical indicia of inner skewed bushing  144  with slot  170 . Then bushing assembly  12  is rotated as a whole and at this time another alphabetical indicia (or perhaps the same alphabetical indicia or perhaps slot  170 ) serves as an alignment or reference marking, such as relative to a marking on the upper control arm  126  or at some other location such as a tab on the upper control arm  126 .  
         [0085]     As shown in  FIG. 7B , inner skewed bushing  144  includes an outer cylindrical surface portion  172 , a head  174 , and a through opening  176 . Outer cylindrical surface portion  172  has a central axis C′. Through opening  176  is defined in part by an inner cylindrical surface portion  178 , which has a central axis D′. Through opening  176  is further defined in part by an inner tapered surface portion  180 , which also has axis D′ as a central axis. Tapered surface portion  180  confronts a tapered stud portion of stud  120 . Axis D′ is skewed relative to axis C′ such that through opening  176  is skewed relative to outer surface cylindrical portion  172 . Outer cylindrical surface portion  172  of inner skewed bushing  144  has a diameter equal to or slightly greater than the inner cylindrical surface portion  152  of outer skewed bushing  142  such that the inner skewed bushing  144  is engaged relatively tightly in the outer skewed bushing  142  so as to minimize, if not prevent, rotation by hand, and permit rotation only with the aid of leverage, such as leverage provided by a pair of wrenches.  
         [0086]     Outer cylindrical surface portion  172  includes an annular retaining groove  186  formed therein for engaging annular barb  157 . Annular retaining groove  186  lies in a plane that is 1) positioned at a right angle relative to axis C′, 2) positioned obliquely relative to axis D′, and 3) positioned at a right angle relative to outer surface cylindrical portion  172 . Annular barb  157  locks into groove  186  and permits inner skewed bushing  144  to be slid into opening  150  and over barb  157  whereupon, upon attempted removal of inner skewed bushing  144  from outer skewed bushing  142 , the right angled wall of barb  157  confronts the lower right angled wall of groove  186 .  
         [0087]     Inner skewed bushing  144  includes a first or lower annular end or surface  188  and a second or upper annular end or surface  190 . Surface  188  lies in a plane disposed at a right angle relative to axis C′. Surface  188 , when inner skewed bushing  144  is engaged in outer skewed bushing  142 , lies within through opening  150  of outer skewed bushing  142  and does not extend beyond annular end  158  of outer skewed bushing  142 . Annular surface  190  lies in a plane disposed at a right angle relative to axis D′.  
         [0088]     Upper annular end or surface  190  is a connector seating annular surface for confronting the lower face (nonslotted face) of castle nut  130 . Connector seating annular surface  190  lies in a plane that is 1) positioned at a right angle relative to axis D′, 2) positioned obliquely relative to axis C′, and 3) positioned obliquely relative to outer surface cylindrical portion  172 . Indicia  184 , namely alphabetical indicia, is formed in surface  190  for incrementally dialing inner skewed bushing  144  to the desired position relative to outer skewed bushing  142 . Preferably, one alphabetical indicia is rotatably aligned with slot  170  to provide the desired skew angle relative to outer cylindrical surface portion  146  of the outer skewed bushing  142 . Then, bushing assembly  12  is preferably as a whole rotated such that another indicia marking  184  (or slot  170 ) is aligned with a portion of upper control arm  126  such as a tab on upper control arm  126 , thereby providing the desired skew angle relative to stud  120  and axle arm  112  and hence providing the desired camber and caster angles to the wheel on spindle  110 . Then castle nut  130  is engaged to the ball stud  120  and tightened upon indicia containing surface  190 . Then cotter pin  132  is inserted into the aperture of the ball stud  120  and one or more ends of the cotter pin are flared out to prevent an unintended turning and disengagement of the castle nut  130  from the stud  120 .  
         [0089]     Head  174  of inner skewed bushing  144  has a width greater than a width of outer surface cylindrical portion  172 . Head  174  is defined in part by outer annular surface  190 , and is further defined in part by an annular seat  196  that rides on annular surface or seat  160  of the head  148  of outer skewed bushing  142 . Annular surface  196  lies in a plane that is positioned at a right angle to axis C′. Head  174  is further defined in part by a polygonal sidewall or surface  200 , best shown in  FIG. 6A . Polygonal surface  200  preferably is hexagonal for engagement by a tool such as a socket wrench such that the inner skewed bushing  144  can be turned or dialed relative to the outer skewed bushing  142 .  
         [0090]     Inner skew bushing  144  further includes a through slot  206  extending from outer surfaces  172 ,  200  to inner surfaces  178  and  180  and further extending from annular end  188  to annular end  190  such that through slot  206  extends entirely through the wall of the inner skew bushing  144 . Slot  206  is parallel to axis C′ and is shown in  FIGS. 6A, 6C ,  7 B, and  7 C. During a camber and caster alignment procedure or method, slot  206  is typically not used.  
         [0091]      FIG. 7C  shows that, when inner skewed bushing  144  is engaged in outer skewed bushing  142  and rotated to what is defined as a neutral or zeroed position, axis A′ and axis D′ are aligned. There is only one such neutral or zeroed position, and in such position axis A′ and axis D′ overlay each other as well as being aligned with one another. At such a position, bushing assembly  12  as a whole acts like a one-piece bushing having no skew and no eccentricity, where eccentricity is defined as a bushing having an axis located elsewhere than at the geometric center. In other words, at the neutral or zeroed position, axis D′ of through opening  176 , which confronts the stud  120  of the upper ball joint  118 , is a central axis relative to the outer cylindrical surface portion  146  of the outer skewed bushing  142 , which is confronted by the cylindrical walls of opening  128  of axle arm  112 .  
         [0092]      FIGS. 7C and 7D  shows that axis B′ is always aligned with and overlaid by axis C′ because axis B′ is the central axis of the through opening  150 , which receives the outer cylindrical surface portion  172 , which in turn has central axis C′. From an operational standpoint, axis B′ and axis C′ are one and the same and may be referred to as axis B° C.′.  
         [0093]      FIG. 7D  shows a maximum skew angle for through opening  176 , which confronts the stud  120  of the upper ball joint  118 , relative to the outer cylindrical surface portion  146 , which is confronted by the cylindrical walls of opening  128  in axle arm  112 . In other words, central axis D′ of through opening  176  of inner skew bushing  144  is disposed at a maximum angle relative to central axis A′ of the outer cylindrical surface portion  146  of outer skew bushing  142 . It should be noted that, at all rotative positions except the neutral or zeroed position, axis A′, axis D′ and axis B‘C’ intersect at only one point. This single point is disposed within through opening  176  such that the single point is disposed within the bushing assembly  12  as a whole.  
         [0094]     It should be noted that incremental and intermediate angles of skew are obtained by rotating the outer and inner skewed bushings  142 ,  144  to positions other than that shown in  FIGS. 7C and 7D . After the desired angle of skew is obtained, whether such skew angle is that shown in  FIG. 7C , is that shown in  FIG. 7D , or is an intermediate skew angle therebetween, such a desired angle is further exploited by rotating the bushing assembly  12  as a whole in opening  128  of axle arm  112  to obtain the desired caster and camber angles.  
         [0095]     By comparing  FIGS. 9C and 10B , it should be noted that through opening  150  is relatively greatly eccentric relative to end surface  158  and relatively minimally eccentric relative to end surface  160 . By comparing  FIGS. 9D and 10B , it should be noted that through opening  176  is relatively greatly eccentric relative to end surface  188  and is relatively minimally eccentric relative to end surface  190 . Such minimal eccentricity is a further feature that permits a greater diameter and greater thickness to each of heads  148  and  174 . Such minimal eccentricity can also be seen in section views  7 A and  7 B. Surface  157  in  FIG. 10B  is a chamfered surface. The ring  159  in  FIG. 9D  is merely a marking formed in surface  190  about the alphabetical indicia.  
         [0096]     It should be noted that each of heads  148  and  174  is tapered. That is, annular surfaces  160  and  162  are oblique relative to each other on outer skewed bushing  142  and annular surfaces  190  and  196  are oblique relative to each other on inner skewed bushing  144 . When rotated to the neutral or zeroed position shown in  FIG. 7C , the tapered heads  148 ,  174  compensate for each other. When rotated to the maximum skew angle, as shown in  FIG. 7D , the tapered heads  148 ,  174  are additive. Such a feature permits the heads  148  and  174  to have a relatively greater diameter, and a relatively greater height (or thickness along the axis A′, B′C′, and D′).  
         [0097]      FIG. 8A  shows the prior art bushing of the Ingalls et al. U.S. Pat. No. 4,420,272 issued Dec. 13, 1983 and entitled Method And Structure For Bearing The Eccentricity Of A Bushing Bore, which is hereby incorporated by reference in its entirety. Such bushing can be referred to as an unfocused bushing. That is, unfocused bushings have two vertical centerlines, and a third vertical, or angled, rotational centerline. One vertical centerline  304  defines the rotational centerline of the larger eccentric, and one vertical centerline  306  defines the rotational centerline of the smaller inner eccentric. The two vertical centerlines  304 ,  306  are parallel to each other and do not intersect. A third centerline  305  located through the smaller inner eccentric is either vertical and parallel, or angled and not parallel, relative to the parallel vertical centerlines  304 ,  306  of both the inner and outer eccentrics. If angled and not parallel the rotational centerline  305  within the smaller eccentric may, or may not, depending on its orientation, intersect continuously with the vertical centerline  306  of the smaller inner eccentric. Regardless of its orientation within the smaller inner eccentric, the angled centerline  305  can at best only briefly intersect with the rotational centerline  304  of the larger eccentric  304  at only one specific rotational position  308  during its rotation. If parallel, the third centerline  305  within the smaller eccentric never intersects with either the larger outer, or the smaller inner, eccentric centerlines. Since the centerline  306  of the inner eccentric does not pass through point  308 , and since the centerline  305  does not remain fixed at point  308  during its rotation around centerline  306 , an unfocused bushing does not automatically rotate to allow a zero offset bushing to be created. Not being able to automatically create a zero offset bushing forces the alignment mechanic to install and then remove a separate zero offset bushing to accurately determine a starting point in order for an accurate wheel alignment correction to be made. This doubles the amount of labor cost to the public for this particular step of wheel alignment.  
         [0098]     Present bushing assemblies  10  and  12  are each a single point focused bushing and each is represented diagramatically in  FIG. 8B . Single point focused skewed bushings have three rotational centerlines that are not parallel to each other. All three centerlines intersect each other at all times at a single unchanging point  307 . One vertical centerline  301  defines the rotational centerline of the outer bushing  42  or  142 . A second centerline  302  defines the rotational centerline of the inner bushing  44  or  144  and is angled in such a way relative to the vertical centerline  301  so as to intersect the centerline  301  at a single fixed point  307  during individual or simultaneous rotation of either the inner or outer bushings along their centerlines. This second centerline  302  defines the rotational centerline of the inner bushing. Within the inner bushing, a third rotational centerline  303  rotates around centerline  302  and is angled relative to the centerline  302  of the inner bushing in such a way as to continuously intersect the vertical centerlines  301  of the outer bushing at exactly the same point  307  as the centerline  302  of the inner bushing. All three centerlines intersect continuously at the single point  307  during all possible combinations of individual or simultaneous rotation. This continuous intersection of all three rotational centerlines at a single point  307  allows larger mechanical offsets to be created to more greatly effect wheel alignment change within the same physical space taken up by an alignment bushing that does not have centerlines that continuously intersect at a single point. The single rotational center point  307  also guarantees that centerline  303  at one point during its rotation around centerline  302  exactly overlays the centerline  301  of the outer bushing. This overlay creates a zero offset bushing assembly as a whole. In this way, a wheel alignment bushing is created that includes all wheel alignment possibilities between zero offset and maximum offset. Creation of a zero offset bushing allows the alignment mechanic to avoid wasting time installing, and then removing, a separate zero offset bushing into the vehicle to determine an accurate starting point for an appropriate wheel alignment correction.  
         [0099]     In  FIG. 8B , the closer the three centerlines come to intersecting with each other at a single point  307 , the greater the bushings offset potential and ability to accurately create a zero offset bushing.  
         [0100]     It should be noted that a three centerline bushing with all three centerlines parallel to each other (no intersection of any of the three centerlines) has the smallest potential offset.  
         [0101]     It should be noted that a three centerline bushing with two of the three centerlines intersecting each other (no matter how briefly) has a larger offset potential.  
         [0102]     It should be noted that a three centerline bushing with all three centerlines intersecting each other continuously through the single point  307  has the most offset potential for any given bushing diameter.  
         [0103]     In  FIG. 8B , it should be noted that centerline  301  is representative of axis A or A′, that centerline  302  is representative of axis BC or axis B° C.′, and that centerline  303  is representative of axis D or D′. Single point  307  is contained within bushing assemblies  10 ,  12 .  
         [0104]     Bushing assembly  10  or bushing assembly  12  can be used as follows in the following alignment operation: 
        1) Take an initial alignment reading to determine whether the vehicle is out of OEM specifications;     2) Remove the tire/wheel assembly and the currently installed bushing from the upper ball joint;     3) Install bushing assembly  10  or  12  in the neutral or zero degree position by dialing the “N” alphabetical indicia of the inner bushing to the slot of the outer bushing. It does not matter at this point in what position the bushing assembly  10  or  12  as a whole is installed because the bushing assembly as a whole is at the neutral or zeroed position;     4) Take a new alignment reading to determine the amount of positive or negative camber and caster changes that are necessary;     5) Refer to a proper chart for the vehicle model that is being serviced;     6) The chart can indicate to what degree the inner bushing should be dialed relative to the outer bushing. For example, the chart can indicate that the inner and outer bushings should be relatively dialed until a certain letter of the inner bushing is adjacent the slot of the outer bushing.        
 
         [0111]     7) It is not necessary to remove the bushing assembly  10  or  12  from the upper ball joint stud to index the inner bushing properly relative to the outer bushing. 
        8) The chart can further indicate to what degree the bushing assembly as a whole should be rotated relative to the ball joint stud. For example, the chart can indicate that the bushing assembly as a whole should be dialed (rotated) until a certain letter is adjacent to a marking on the axle arm or ball joint stud or other location on the vehicle.     9) Install the pinch bolt or castle nut and torque to the manufacturer&#39;s specifications. Then install the snap ring or cotter pin.     10) Proceed with alignment and road test the vehicle.        
 
         [0115]     It should be noted that indicia  84  and  184  can be formed in other annular or generally circular locations on the inner skewed bushings  44 ,  144  as, for example, annular surface  90  and polygonal surfaces  100 ,  200 . Further, if desired, such alphabetical indicia may be formed on the outer skewed bushings  42 ,  142  and where such alphabetical indicia are rotatably alignable with a marking such as slot  106 ,  206  on the inner bushing  42 ,  142 .  
         [0116]     It should be noted that, with the present dual axis bushing assembly  10  or  12 , a skew or throw improvement over prior art bushings of about 25% is achieved with the orientations shown in  FIGS. 3D and 7D . Further, prior art bushings do not dial in true zero. For example, bushing  10  can have a camber and caster adjustment range of zero degrees to plus or minus 4.0 degrees. Bushing  12  can have a camber and caster adjustment range of zero degrees to plus or minus 3.2 degrees.  
         [0117]     It should be noted that bushings  10 ,  12  can be machined from steel or produced from a powdered metal and molded or produced from a powdered metal and molded and then machined.  
         [0118]     It should be noted that slots  70 ,  106 ,  170 ,  206  provide a degree of flexibility to the bushing assemblies  10 ,  12 .