Abstract:
An apparatus allows for the independent adjustment of caster and camber for vehicles utilizing MacPherson strut front suspensions. The apparatus has, in stacked arrangement, a fastener plate, a lower plate, and an upper plate. Camber adjustments are generally made by manipulation of the lower plate and caster adjustments are generally made by manipulation of the upper plate. The upper plate may be mounted in two different positions to allow for different camber adjustments, such as for competitive situations and non-competitive situations. The device utilizes a thrust bearing having a race in the upper face of the spring perch and an opposing race which mounts around the base of the bearing cup.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation-in-part application of U.S. patent application Ser. No. 14/043,743 which was filed on Oct. 1, 2013. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to automobile suspension systems and more particularly to devices which provide for the independent adjustment of camber and caster. Some automobiles, such as Ford Mustangs dating from 2005 to the present, hereinafter collectively referred to as “2005+ Mustangs”, are equipped from the factory with MacPherson strut front suspensions. The camber and caster angles for the MacPherson strut suspensions found in the 2005+ Mustangs are fixed at the factory to a set position which reduces maintenance. The MacPherson strut configuration utilized in the 2005+ Mustangs have a strut rod at the top of the strut which mounts to a plate or other attachment assembly within a strut tower of the chassis as known in the art. The OEM upper strut mounting assemblies on these vehicles typically do not allow for camber or caster adjustments, although some vehicles may have mechanisms which allow for camber adjustment, such as slots in the strut tower which allow some camber adjustment. 
     However, while the fixed camber and caster settings may provide performance which is generally satisfactory for every day commuting purposes, the fixed settings do not provide the performance sought by automotive enthusiasts who desire to use their vehicles in competitive events such as road rallies, road racing, drag racing, etc. These users prefer to have precise control of the handling of their vehicles for the particular application. For example, in road racing, negative camber, where the bottom of the wheel is further out than the top of the wheel, is desirable because it improves tire grip when cornering. However, in drag racing, where maximum straight-line acceleration is desired, the greatest traction is obtained where the wheel has no camber angle and the tire tread is flat on the road. 
     Moreover, competitive owners frequently lower their vehicles to improve performance, which puts the camber out of the factory specification, which can increase wear on the tires and have a negative impact on handling. 
     It is also desirable to be to adjust the caster angle, which is the angular displacement between a vertical axis and the pivot line (an imaginary line running through the center of the upper ball joint to the center of the lower ball joint. Improper caster settings make it more difficult to maintain a straight line and can make steering heavier and less responsive. Caster adjustments may correct steering problems, such as causing the vehicle to pull toward the side with less positive caster. Positive caster improves the vehicle&#39;s straight line stability, which is a desired quality for drag racing. 
     Thus, it is desirable to have an apparatus which may be installed to replace the original manufacturer&#39;s parts, where the apparatus allows the adjustment of camber and caster in vehicles, such as 2005 and later Ford Mustangs, and other vehicles which have factory pre-set and non-adjustable caster and camber settings 
     SUMMARY OF THE INVENTION 
     Embodiments of the method and apparatus disclosed herein provide a solution to the problem described above. For purposes of this disclosure and the claims herein, the terms “front” and “back” (or “forward” and “rearward”) respectively indicate directions which are toward the front and back of the vehicle. Likewise, the terms “up” and “down” (or “upward” and “downward”) respectively indicate directions which are toward the ground and toward the top of the vehicle. 
     Embodiments of the apparatus for adjusting caster and camber may be generally summarized according the following description. The apparatus has, in stacked arrangement, a fastener plate, a lower plate, and an upper plate. Camber adjustments are generally made by manipulation of the lower plate and caster adjustments are generally made by manipulation of the upper plate. 
     At least one fastener plate is utilized to secure the position of a coil spring-strut assembly of a MacPherson-syle front suspension assembly. The different plates of the device are used to adjust camber and caster. The fastener plate (or fastener plates) may have a plurality of upwardly facing threaded fastening members, typically threaded studs attached or inserted through the fastener plate, where the fastening members extend upwardly from an upwardly facing of the fastener plate. These fastening members attach to a portion of the vehicle chassis known as the strut tower. Typically, the fastening members extend through openings at the top of the strut tower, where nuts are made up onto the threads of upwardly extending fastening members. If a single fastener plate is utilized, the interior of the fastener plate has a cutout portion defined by an interior wall. If more than one fastener plate is used, the positions of the installed multiple fastener plates define a cutout portion. 
     Alternatively, the fastener plate may have a plurality of threaded apertures adapted to receive threaded fasteners inserted through openings at the top of the strut tower, with the threaded ends of the fasteners received by the threaded apertures of the fastener plate. 
     Disposed in general overlaying relation to the fastener plate is the lower plate. The lower plate has a downwardly facing bottom side positioned adjacent to the upwardly facing face of the fastener plate. The threaded fastening members extend through openings in the lower plate. The lower plate has a bearing cup, referred to herein as the shaft housing, which substantially depends from the downwardly bottom side, but may also have a portion extending above the upwardly top side of the lower plate. The shaft housing is typically a cylindrical structure with an opening extending throughout its length. The shaft housing extends through the interior cut-out portion of the fastener plate. The bore of the shaft housing is for receiving an end of a strut shaft therethrough, along with bearing or bushing components which mount within the shaft housing and allow rotation of the shaft housing. The lower plate is releasably adjustable with respect to the fastener plate along a first axis, hereinafter referred to as the “X” axis, and along a second axis, hereinafter referred to as the “Y” axis. The X axis and the Y axis are substantially non-parallel and may be perpendicular to one another. 
     Disposed in general overlaying relation to the lower plate is the upper plate. The upper plate has a downwardly facing bottom side positioned adjacent to a top face of the lower adjustment plate. The upper plate has openings which sufficiently align with the openings in the lower plate to allow the threaded fastening members to extend through the openings in the upper plate. The interior of the upper plate may have a cutout portion defined by an interior wall, which allows for any portion of the shaft housing which extends above the top side of the lower plate to move within the cutout portion. The upper adjustment plate and the lower adjustment plate are jointly configured for allowing relative movement between the two plates along the X axis but restricting movement along the Y axis. 
     The lower plate has a plurality of upwardly facing protruding members which extend upwardly from the top face of the lower plate which are each received within a corresponding elliptical aperture in the upper plate. The engagement of the protruding members with the corresponding elliptical apertures allows relative movement between the upper plate and the lower plate along the X axis while inhibiting relative movement between the upper plate and the lower plate along the Y axis. A thrust bearing assembly couples to the lower plate. The thrust bearing assembly may have an upper member having an upper race, a spring perch comprising a lower race, and plurality of ball bearings disposed between the upper race and the lower race. The upper member and the spring perch have openings for receiving the shaft housing which couple the spring perch, and therefore the thrust bearing assembly to the lower plate. The spring perch provides a seat for the upper end of the coil spring which is a component of a MacPherson strut suspension. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an embodiment of the apparatus mounted on a strut shaft. 
         FIG. 2  shows an embodiment of the apparatus for adjusting caster and camber, viewed from the bottom, as mounted within a strut tower. 
         FIG. 3  shows an exploded view of an embodiment of the apparatus. 
         FIG. 4  shows an exploded view of an alternative embodiment of the apparatus, with the thrust bearing in an assembled configuration. 
         FIG. 5  shows a bottom view of an embodiment of the apparatus showing detail of a portion of the thrust bearing. 
         FIG. 6  shows the components of an embodiment of the thrust bearing assembly. 
         FIG. 6A  shows a sectioned view of the thrust bearing assembly of  FIG. 6 . 
         FIG. 6B  shows a detailed view of the sectioned view of  FIG. 6A . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     Referring specifically to the figures,  FIG. 1  shows a perspective view of an embodiment of the disclosed camber/caster adjustment plate apparatus  10  (hereinafter, “apparatus”). As shown in  FIG. 1 , the apparatus is in a stacked configuration having an upper plate  12 , a lower plate  14 , and a fastener plate  16 . A strut shaft  18  from a MacPherson strut (not shown) extends through a shaft housing  20  and is retained within bearing assembly  22 . As shown in  FIG. 2 , the adjustment plate apparatus  10  is fastened to an upper surface  24  of strut tower  26 . Referring to  FIGS. 1 and 2 , once caster and camber are adjusted as desired, the adjustment plate apparatus is fastened to the upper surface  24  by fastening members  28  which extend through the upper surface  24  of strut tower  26  into threaded apertures  67  within fastener plate  16 . Alternatively, as shown in  FIG. 3 , fasteners  28 ′ may be integral to fastener plate  16 ′ and may extend upwardly and may be secured to the upper surface of strut tower  26  by nuts  30  and washers  32 . In either case, the adjustment plate apparatus is also secured by either inserting a bolt (not shown) into either one of the threaded apertures  42  or nuts  42 ′, which may be pressed-in and/or depend from lower face  50  or by placing a nut on fastener  42 ″. The upper plate may comprise a forward side  51 , a rearward side  53 , a left side  55  and a right side  57 . 
     Fastening members  28 ,  28 ′ extend through elliptical apertures  29  in lower plate  14  where the elliptical apertures have a long axis generally parallel to the X axis. The positioning of fastening members  28  along the X axis within the elliptical apertures  29  in the lower plate  14  generally allows for making camber adjustments. It is to be noted that elliptical apertures  29  are wide enough to allow some motion of the stacked adjustment plates in the direction of the Y axis for adjusting caster Fastening members  28 ,  28 ′ extend through elliptical apertures  31  in upper plate  12  (or  12 ′), which have a long axis generally parallel to the Y axis. The positioning of fastening members  28  along the Y axis within the elliptical apertures  31  in the upper plate generally allow for making caster adjustments. 
     Fastening members  28 ,  28 ′ are attached through, attached to, or integral to fastener plate  16 . As shown best in  FIGS. 3-4 , fastener plate  16  has an interior cut-out portion  34 , which is bounded by an interior peripheral wall  36 . Similarly, upper plate  12  has an interior cut-out portion  38  which is bounded by an interior peripheral wall  40 . Interior cut-out portions  34  and  38  are generally elliptical in shape and allow movement of the plates and the shaft housing  20  prior to the tightening of nuts  30  on fastening members  28 . 
     In addition to being fastened to the upper surface  24  by fastening members  28 ,  28 ′, for the purpose discussed below, upper plate  12  comprises either a threaded aperture  42 , a pressed-in nut  42 ′, or an integral fastener  42 ″, any of which are disposed within an extending tab  44  which extends outside of the sides  46  of lower plate  14 . Any one of the threaded aperture  42 , the pressed-in nut  42 ′ or the integral fastener  42 ″ of extending tab  44  are utilized to secure upper plate  12  to the upper surface  24  of strut tower  26 . This feature allows the upper plate  12 , which is manipulated to adjust caster, to be secured, while still allowing manipulation of lower plate  14  in the direction of the X axis so that camber adjustment, which is made by manipulation of the lower plate  14  along the X axis, may be accomplished independent of the caster setting. 
     Upper plate  12  may comprise a single extending tab  44 , or may have an extending tab  44  on either side of the upper plate. The extending tabs may be either on the left side  55  or the right side  57 , or on both sides of upper plate  12 . As shown best in  FIG. 2 , the tabs  44  may be offset from one another, such that, with reference to the X axis, one tab is at a different position than the second. This offset may be utilized to provide different camber settings according to which setting is utilized. For example, the offset may be utilized to generally set a first camber setting utilized for competition purposes and a second camber setting utilized for non-competition purposes. The desired camber setting can then be realized by rotating the upper plate  12  by 180 degrees to select the desired tab and aligning the selected tab with an aperture in the upper surface  24  of the strut tower  26  and either making up a bolt into the threaded aperture  42 , pressed-in nut  42 ′, or placing a nut on integral fastener  42 ′. 
     In order for camber and caster to be set independently from one another, it is necessary that lower plate  14  may be moved relative to upper plate  12  along the X axis after the camber adjustment has been fixed by securing upper plate  12  to the upper surface  24  of the strut tower  26  as described above. However, once upper plate  12  has been secured to the upper surface  24  of the strut tower  26 , further movement of lower plate  14  along the Y axis is inhibited by an interlocking structure between the two plates. This interlocking structure generally comprises the engagement of a plurality of protruding members  48  which extend upwardly from the top face  50  of the lower plate  14 , where each protruding member is received within an elliptical aperture  52  in upper plate  12 ,  12 ′, where each elliptical aperture corresponds to each of the protruding members  48 . The protruding members  48  have a diameter which is sufficiently small to fit within elliptical apertures  52 , but which is large enough to inhibit or restrict any appreciable motion along the Y axis. However, elliptical apertures  52  are sufficiently long to allow for approximately one inch of motion along the X axis. Protruding members  48  may be pins attached to top face  50 , or may be installed through apertures in lower plate  14 , or lower plate  14  may be machined such that the protruding members are machined from the fabrication material and the protruding members are integral posts machined into lower plate  14 . 
     Fastener plate  16  may be generally, but not necessarily, rectangular, having a left side  59 , a right side  61 , a forward side  63 , and a rearward side  65 . Either the left side  59  and/or the right side  61  may have a cut-out portion  60 ,  62 . The cut-out portions  60 ,  62  are adapted to receive an edge of pressed-in nuts  42 . Likewise, the interior peripheral wall  36  which defines interior cut-out portion  34  of fastener plate  16  may have semi-circular apertures  64 ,  66 . The engagement of the edges of the pressed-in nuts  42  into cut-out portions  60 ,  62  serve to lock upper plate  12  to lower plate  16 . 
     Embodiment of the device may comprise a thrust bearing assembly  100  which comprising an upper member  102  having an upper race  104 , a spring perch  106  comprising a lower race  108 , and plurality of ball bearings  110  disposed between the upper race and the lower race. Upper member  102  and spring perch  106  may each have an hemi-spherical or elliptical groove  112 ,  114  in the opposing faces of each which may be utilized for disposing O-ring  116 . The upper member  102  and spring perch  106  each have axially-aligned openings  118 ,  120  [s] for receiving the shaft housing thereby coupling the spring perch to the lower plate. 
     With the various nuts and fasteners holding the apparatus in place in a loosened state, the lower plate  14  and the upper plate  12  may be positioned along the X axis and the Y axis. Caster may be adjusted by manipulating the coil spring-strut assembly and then locking the upper plate  12  into position by attaching the upper plate to the upper surface  24  of strut tower  26  by insertion and tightening of a fastener into threaded aperture  42  or pressed-in nut  42 ′ or tightening a nut on integral stud  42 ″. 
     Once caster is set, the coil spring-strut assembly may be manipulated to adjust camber, and nuts  30  tightened on threaded fasteners  28 , or threaded fasteners  28 ′ made up to lock the camber adjustment into position. As discussed above, a preliminary camber setting may be realized by selecting whether to attach a fastener to either the left side  55  or right side  57  of upper plate  12 , because the attachment points (e.g., threaded aperture  42 ) on the left side and the right side may be offset with respect to the X axis. For example, the threaded aperture on the left side  55  may have a center which is half-an inch forward of the center of the threaded aperture on the right side  57 . 
     While the above is a description of various embodiments of the present invention, further modifications may be employed without departing from the spirit and scope of the present invention. Thus the scope of the invention should not be limited according to these factors, but according to the following appended claims.