Land vehicles – Wheeled – Running gear
Reexamination Certificate
2001-07-31
2003-05-06
Morris, Lesley D. (Department: 3611)
Land vehicles
Wheeled
Running gear
C280S086754, C280S093512
Reexamination Certificate
active
06557872
ABSTRACT:
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'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.
For some vehicles, such as Jeep Grand Cherokee, Jeep TJ and Dodge 1500, there are presently two means available to adjust camber angle on the front wheels of the vehicles. These vehicles are provided with no factory adjustment of camber angle, original equipment consisting of a lower ball joint that can pivot and rotate and an upper ball joint that is fixed in all but vertical movement (to allow for tolerance in the axle and spindle machinings). While typically referred to herein, and in the automotive industry, as a “ball joints”, this is not technically correct terminology since such units pivot about their shaft centerlines and do not pivot and rotate about a fixed “ball”. The units are actually upper or lower spindle pivots.
Nevertheless, in allowing for axial travel of the shaft, the unit incorporates a plastic sleeve with a ridge mated to a wide groove in the shaft to prevent the shaft from separating from the body. This method is not particularly vigorous but may be adequate since there is no vertical force transmitted through the upper pivot during vehicle use (even though there may be during installation and removal of the upper pivot).
One means for camber adjustment is a copy of the original equipment upper pivot and consists of replacing the upper spindle pivot with a unit having a rotating shaft that is offset and angled (to maintain shaft alignment with the lower ball joint pivot point) in the unit body which is press fit into the top of the axle. This unit provides only four different offsets (0.5, 1, 1.5, and 2 degrees), but the unit can be rotated as installed to yield combinations of caster and camber adjustment. Because of the limited offsets available, this unit addresses only a limited range of combinations of camber/caster problems.
A second known means addresses adjustability at the lower ball joint. A new ball joint with a machined offset stud replaces the original part. Currently, only two offsets are available with such means, but as above the unit can be rotated when installed to provide combinations of caster and camber adjustment. Problems occur with this unit, however, since it addresses only a few of the possible combinations of camber/caster problems, and because it may also adversely affect steering since the offset in the ball joint will change camber and caster as the wheel is steered back and forth. The lower ball joint is also vertically and laterally load bearing and more prone to failure than the upper ball joint, making it a less than ideal candidate for such replacements. Further improvements could thus be still be utilized.
SUMMARY OF THE INVENTION
This invention provides apparatus for selective positioning of a vehicle wheel suspension, or steering, spindle or knuckle relative to a control arm or knuckle mount 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, provides for adjustment of wheel camber independent of caster adjustment, and is versatile, offering a wide range of possible offsets.
The apparatus includes an insert (or body) that is secured with the knuckle mount. An elongated slot extends through the insert between first and second contact surfaces, the second contact surface having positioning structure defined thereat. A lower support assembly, secured at the knuckle and positioned through the slot of the insert, is selectively linearly located and secured along the slot. Mating positioning structure at a surface of a flange at the lower support assembly is engageable by the positioning structure of the insert. The lower support assembly preferably includes a bearing insert fit in an interior cavity of a support unit having the flange thereat. A shaft is receivable through the bearing insert for maintenance in the cavity and is secured at the knuckle.
A guide channel is defined at the first contact surface of the insert. An upper support assembly includes a securing member and a slide receivable at one part of the lower support assembly. The slide is linearly moveable in the guide channel. The securing member is receivable at an engagable (preferably threaded) end of the lower support assembly to thereby secure engagement of the positioning structures and selected location of the lower support assembly along the slot.
The apparatus of this invention allows for large camber/caster angle adjustments by providing a means to change the upper shaft offset while maintaining the alignment with the lower ball joint, and is a suitable replacement for original equipment. The apparatus incorporates teeth to maintain angular position and can be installed in any rotation to allow for all combinations of camber/caster angle in 0.25 degree increments (from 0 to 2.5). Angular adjustability of the apparatus shaft centerline provides complete camber/caster angle cover
Burdick Harold A.
Ingalls Engineering Company, Inc.
Morris Lesley D.
Winner Tony
LandOfFree
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