Abstract:
A replacement ball joint apparatus and method for conveniently modifying motor vehicle suspension camber, caster or camber/caster combination angle by means of repositioning a wheel spindle top or bottom relative to a control arm. The apparatus includes a mount assembly secured at one end of a ball joint which is connectable at its other end to the spindle, the mount assembly having a slide with a stud extending therefrom. A guide assembly is securable at the control arm and receives and guides the slide.

Description:
FIELD OF THE INVENTION 
     This invention relates to wheel adjustment/alignment apparatus and methods for vehicles, and, more particularly, relates to apparatus and methods for adjusting the control arm/wheel spindle relationship at an upper or lower ball joint connection to produce changes in the camber, caster or camber/caster combination angle of a vehicle wheel. 
     BACKGROUND OF THE INVENTION 
     Most vehicles consist of a tire/wheel mounted to a spindle which is attached to the vehicle through upper and lower control arms with the main connection being through ball joints mounted to the control arms. Some vehicles, however, are manufactured without provision for adjusting camber angle in the wheels. For example, some vehicles utilize an ‘A’ shaped upper control arm with ‘silent-bloc’ type pivot isolators pressed into the inner pivot locations of the arm. The inner control arm in some such cases has a ‘u’ shaped bracket welded into it, with cross-holes in the inner bracket and inner control arm for locating the mounting bolts that engage and clamp the ‘silent-bloc’ pivot isolators. This arrangement locates the inner pivots of the upper control arm in a fixed position with no means of adjustment. 
     The camber and caster angles of the tire/wheel (relative to the vehicle frame) directly effect vehicle handling and tire wear and is therefore of great importance. Camber angle is typically specified by the factory at a specific vehicle ride height (the distance from the ground to some point in the vehicle suspension corresponding to the vehicle frame center of gravity). The camber angle established between the plane of the tire and wheel and the vertical plane through the vehicle frame is directly impacted by any changes in the suspension components. Such changes can occur through damage to the components or through modification, intentional or unintentional, to the vehicle ride height. Thus, vehicles with raised or lowered ride height or damaged suspension links will typically not maintain proper camber angle and require means for readjusting the camber angle to the original specifications if handling and tire longevity are not to be sacrificed. Moreover, it may become desirable to correct a mis-aligned vehicle with other than strictly camber corrections. 
     One current means for adjusting camber angle consists of changing the relative position of the control arm to the vehicle at the body mounting points. This allows the control arm, and thus the ball joint position, to be moved laterally with respect to the vehicle, thereby changing the camber angle of the spindle and the tire/wheel. This method will not work if the vehicle&#39;s control arm mounting scheme prevents replacing the fixed control arm body mounts with an adjustable mounting apparatus. 
     Another current means for adjusting camber angle provides for replacement of the upper or lower ball joint with an offset ball joint that, when rotated, allows changes of the position of the spindle mounting point around an offset arc. While this enables the camber angle to be modified, it at the same time modifies the caster angle, sometimes undesirably, due to its fixed radial offset arc. Further improvements could thus be utilized 
     SUMMARY OF THE INVENTION 
     This invention provides apparatus and method for selective positioning of a vehicle ball joint relative to a control arm to provide adjustability of wheel camber, wheel caster, and/or a combination of wheel camber and caster. The apparatus is simple to install and adjust, requires no modification of other suspension components, and provides for adjustment of wheel camber independent of caster adjustment. 
     The apparatus includes a mount configured to be secured at an end of the ball joint, the mount having a stud extending from a slide. A guide is securable at the control arm and receives and rotationally stabilizes the slide of the mount. The guide has a slot for receiving the stud of the mount therethrough, the stud and the slide thus movable linearly at the guide. 
     An insert is installed through an opening in the control arm with a rim thereof extendible through the control arm opening and receivable adjacent to the guide. A slot in the insert is substantially coextensive with the slot of the guide, the stud extending therethrough. A fastener is engageable with the stud to secure the selected position of the ball joint by securing the position of the stud relative to the slots in the insert and the guide. The ball joint may be pre-installed in the apparatus of this invention (and thus a part thereof), or provided separately from the apparatus of this invention for installation by service personnel. 
     The method of this invention provides for adjusting the relative position of a vehicle ball joint and a central axis of the control arm opening. The method includes the steps of affixing a stud to the ball joint and positioning the stud through the control arm opening. Linear movement of the stud perpendicular to the axis of the control arm opening is guided while rotational movement of the stud in the opening is stabilized. When desired adjustment is achieved, the stud is secured at the selected position relative to the axis of the control arm opening. 
     It is therefore an object of this invention to provide apparatus and methods for selective positioning of a vehicle ball joint relative to a control arm to provide adjustability of wheel camber, wheel caster, and/or a combination of wheel camber and caster. 
     It is another object of this invention to provide an apparatus for selective vehicle wheel angle positioning that is simple to install and adjust on a vehicle, requires no modification of other suspension components, and provides for adjustment of wheel camber independent of caster adjustment. 
     It is still another object of this invention to provide an apparatus for selective positioning of a vehicle ball joint securable between a control arm and a wheel mounting, the apparatus including a mount configured to be secured at an end of the ball joint and including a stud extending from a slide, and a guide securable at the control arm and receiving and rotationally stabilizing the slide of the mount thereat, the guide having a slot for receiving the stud of the mount therethrough, the stud and the slide movable linearly at the guide. 
     It is yet another object of this invention to provide an apparatus mountable at a vehicle control arm opening and at a spindle to provide selectable camber correction of a vehicle wheel including an insert having a rim and a slot, the rim extendible through the control arm opening, a guide receivable adjacent to the rim of the insert and including a slot substantially coextensive with the slot of the insert, a slide with a stud extending from one side thereof and receivable at the guide with the stud receivable through the slots of the guide and the insert, a ball joint affixable at one end to the spindle and at another end to the slide, and a fastener engageable with the stud. 
     It is yet another object of this invention to provide a method for adjusting relative position of a vehicle ball joint and a central axis of a control arm opening including the steps of affixing a stud to the ball joint, positioning the stud through the control arm opening, guiding linear movement of the stud perpendicular to the axis of the control arm opening while rotationally stabilizing the stud in the opening, and securing the stud at a selected position relative to the axis of the control arm opening. 
     With these and other objects in view, which will become apparent to one skilled in the art as the description proceeds, this invention resides in the novel construction, combination, arrangement of parts and method substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that changes in the precise embodiment of the herein disclosed invention are meant to be included as come within the scope of the claims. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings illustrate a complete embodiment of the invention according to the best mode so far devised for the practical application of the principles thereof, and in which: 
     FIG. 1 illustrates a typical suspension system on a vehicle as supplied by a manufacturer; 
     FIG. 2 illustrates the suspension system of FIG. 1 with the apparatus of this invention installed; 
     FIG. 3 is a perspective view of the camber/caster adjusting apparatus of this invention; 
     FIG. 4 is a front elevation view of the apparatus of FIG. 3; 
     FIG. 5 is a side elevation view of the apparatus of FIG. 3; 
     FIG. 6 is a top elevation view of the apparatus of FIG. 3; 
     FIG. 7 is a sectional view taken along section line  7 — 7  of FIG. 4; and 
     FIG. 8 is an exploded view of the camber/caster adjusting apparatus of this invention. 
    
    
     DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates a typical suspension system on a vehicle as supplied by the manufacturer. Upper control arm  10  and lower control arm  12  are both attached to the vehicle frame (not shown). Spindle  14 , which includes wheel mount  16  for supporting a wheel with a tire mounted thereon (not shown), is pivotably attached to each control arm through upper ball joint  18  and lower ball joint  19 , the ball joints spaced a fixed distance apart by spindle  14 . 
     FIG. 2 shows the suspension of FIG. 1 with camber/caster adjusting apparatus  20  of this invention replacing the factory ball joint  18  for selective translation of the position of the upper ball joint along a linear distance “Y”, either inward towards the vehicle frame or outward away from the vehicle frame. When set as illustrated and discussed in greater detail hereinbelow, the effect of movement in the “Y” direction will be to decrease or increase, respectively, the camber angle established by the plane of the tire and wheel with the vertical plane of the vehicle frame in the direction from front to back of the vehicle. While use with the upper ball joint is illustrated herein, the apparatus could be applied to replace lower ball joint  19  and/or applied at both locations. 
     Camber/caster adjusting apparatus  20 , as shown in FIGS. 3 through 8, includes guide assembly  21  and mount assembly  22 . Guide assembly  21  includes insert  23  and guide plate  24  maintained at opposite sides of control arm opening  25  (see FIG.  8 ). Mount assembly  22  includes slide  26  having offset stud  28  extending therefrom through opening  29 . Ball joint  30  is held at slide  26  by collar  32 . The apparatus is held in relative positions, as discussed hereinafter, by fastener  34  (for example a flange nut), ball joint  30  affixable at spindle  14  conventionally. 
     Insert  23  is pressed into opening  25  of upper control arm  10  (and/or lower control arm  12 ) in place of the factory supplied ball joint ( 18  of FIG.  1 ). For camber only adjustment, insert  23  is oriented along the neutral caster angle by alignment of orientation mark  35  on the control arm (see FIG. 2) and a corresponding dimple or other orientation mark  36  on insert  23 . Guide plate  24  and insert  23  each have a slot  38  and  40 , respectively, which are substantially coextensive and along which stud  28  is linearly movable. Substantially parallel guide ridges  42  and  44  at guide plate  24  maintain rotational stability and guide linear movement of slide body  46  of slide  26 , by guiding engagement adjacent to spaced substantially parallel edges  48  and  50  of slide body  46 . 
     While a particular structure is shown for the guiding and stabilizing interrelationship of guide plate  24  and slide  26 , many different configurations at guide plate  24  and mating configuration at slide  26  could be utilized to achieve the same purpose. For example, the guide ridges may be positioned at slide  26  and the matable edges at guide plate  24 , or multiple spaced channels or a single centered channel could be provided at either guide plate  24  or slide  26  with corresponding structure at the other configured to ride in the channel or channels. 
     Insert  23  includes a flange  52  and rim  54 , slot  40  defined through rim  54 . Rim  54  extends through opening  25  of control arm  10  and is received adjacent to annular extension  56  of guide plate  24 . Ball joint  30  is secured at slide  26  by means of a press fit of ball joint end  58  and slide  26  into collar  32  with the addition of a staking process to provide a material deformation of collar end  60  over annular lip  62  of slide  26  to mechanically retain the unit (see FIG.  7 ). Ball joint  30  may be a factory supplied ball joint and is attached at its other end to spindle  14  using conventional means (applying nut and pin assembly  64  to lower threaded stud  66  after application thereof through opening  67  of spindle  14 , for example). 
     When ball joint  30  is connected to slide  26 , it can be seen that the central longitudinal axis of stud  28  is offset relative to the central longitudinal axis of ball joint  30 . This offset provides greater extent of wheel angle adjustability, since neutral adjustment, corresponding to alignment of the central axis of ball joint  30  (vertical axis in the FIGURES) with the central axis of opening  25  in control arm  10  (and thus the central axis of insert  23 ), locates stud  28  near an end of slots  38  and  40  of guide plate  24  and insert  23 . 
     In use, insert  23  is installed into opening  25  of vehicle suspension control arm  10  (or other selected member) with orientation mark  36  at a selected position to achieve the desired direction of angle adjustability. For example, to allow camber only adjustment, insert  23  should be mounted with marks  35  and  36  aligned as shown in FIGS. 2 and 8 (caster neutral alignment), so that the length of slots  38  and  40  of guide plate  24  and insert  23  are also aligned with the guide marks. 
     Guide plate  24 , with slide  26  thereat having stud  28  extending through slot  38 , is positioned at the opposite side of control arm  10 . Ball joint  30  may be attached to spindle  14  in advance of or after installation of mount assembly  22  at guide assembly  21  with stud  28  extending through slot  40  of insert  23  (and thus through opening  25  of control arm  10 ) and held by nut  34 . Slide  26 , with edges  46  and  48  engaging ridges  42  and  44  of guide plate  24  to stabilize and guide slide  26 , when moved in guide plate  24  allows only linear movement of stud  28  in opening  25  perpendicular to the axis of the opening. This sliding movement provides tire/wheel camber adjustment without affecting caster angle (when aligned for caster neutral adjustment as shown in FIG.  2 ). When the desired angle is achieved (with ball joint  30  and the central axis of opening  25  of control arm  10  in a selected relative position), nut  34  is tightened to retain the interrelationship of the components thus established by securing stud  28  at the selected position relative to the axis of opening  25  and along slots  38 / 40  and slide  26  at guide plate  24 . 
     Should readjustment be desired, nut  34  may be loosened and mount assembly  22  of apparatus  20  can be moved inward (towards the vehicle frame) or outwards (away from the frame) by moving threaded stud  28  in guide assembly slots  38 / 40  until the corrected angle is achieved. The position of apparatus  20  is then fixed by applying sufficient torque to flange nut  30 . 
     As may be appreciated, the apparatus of this invention could be modified for installation in such a way as to affect only caster angle or in such a way as to affect both caster and camber angles. A geometric relationship exists between the upper and lower wheel spindle connections (ball joints  18  and  19 ) and the camber and caster angles of the wheel to the vehicle. As previously indicated, altering the position of one of the ball joints in the neutral caster direction affects the camber angle in a desired fashion. Extending this to caster and camber/caster combination corrections and adjustments, the camber/caster adjusting apparatus of this invention can be used to adjust caster only angles or some combination of camber and caster. If so desired, by rotating insert  23  to another position of orientation mark  36  relative to mark  35  on upper control arm  10  during installation, camber/caster adjusting apparatus  20  can be rotated in a predetermined fashion to provide for adjustment of caster only or some combination of camber and caster angles.