CA1316115C - Device for adjusting caster - Google Patents

Device for adjusting caster

Info

Publication number
CA1316115C
CA1316115C CA000574035A CA574035A CA1316115C CA 1316115 C CA1316115 C CA 1316115C CA 000574035 A CA000574035 A CA 000574035A CA 574035 A CA574035 A CA 574035A CA 1316115 C CA1316115 C CA 1316115C
Authority
CA
Canada
Prior art keywords
bushing
rod member
caster
disposed
attached
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CA000574035A
Other languages
French (fr)
Inventor
John Specktor
Gerald A. Specktor
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SHIM-A-LINE Inc
Original Assignee
SHIM-A-LINE, INC.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SHIM-A-LINE, INC. filed Critical SHIM-A-LINE, INC.
Application granted granted Critical
Publication of CA1316115C publication Critical patent/CA1316115C/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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  • Body Structure For Vehicles (AREA)
  • Vehicle Body Suspensions (AREA)

Abstract

DEVICE FOR ADJUSTING CASTER
ABSTRACT OF THE DISCLOSURE
A device is used to adjust caster of a wheel in a suspension system that includes a rod member that affects the caster of the wheel. A portion of the rod member is disposed within a bushing that is attached to the vehicle. The device includes a curved longitudinal member for insertion between the portion of the rod member disposed within the bushing and the bushing.

Description

~31~

DEVICE FOR ADJI~STING CASTER
_ BACKGROUND OF THE INVENTION
_ 1 Field of the Invention The present invention relates to devices for ; adjusting caster of a vehicle wheel, and in particular, it relates to a device that adjusts the caster in a suspen~ion 6ystem having a rod member that affects caster with the rod member having a portion disposed in a bushing attached to the vehicle.
2 Description of the Prior Art.
.

Certain suspenQion systems, such as are used in a Ford pick-up with a twin I-beam frame construction, have a radius arm that extends from an I-beam rearwardly to a radius arm bushing that i8 attached to a vehicle frame member. Both left and right front suspension systems contain such a radius arm. The radius arm bushing i8 typically made of a hard rubber. At first, the bushing fits snugly and holds the radius arm in the position selected by the manufacturer of the automobile. However, due to the action of the end of -the radius arm against the bushing over a period of time along with the coil spring settling, a small amount of play develops in the end o~ the arm, which results in the caster of the wheel and handling of the vehicle being affected.
Other vehicles with stabilizer bars that are held with bushings have similar correction problems.
The prior art method of corre~ting this play is to replace the bushing. This requires a good deal of labor since the radius arm ha~ to be disconnected and removed from the bushing and the bushing replaced.

1 3 1 6 1 ~ 5 SUMMARY OF THE INVENTION
The present invention includes a method and a device for correcting caster of a vehicle suspension system having a rod member that affects the c~ster of the wheel with a portion of the rod member being disposed within a bushing attached to the vehicle.
The device includes a curved longitudinal member for insertion between the portion of the rod member disposed within the bushing and the bushing.
In one case, where the rod member is a radius arm, the device is inserted between an end of the radius arm within the bushing and the bushing. In another case, where the rod member is a stabilizer bar having a portion retained within the bushing, the device is inserted between the stabili~er bar and the bushing.
The method of the pre~ent invention in the case of the radius arm includes removing the nut, washer and insulati~n, retaining the end of the radius arm within the bushing, and inserting between the end of the radius arm and the bushing, a longitudinal main body portion being curved along a longitudinal axis, either above the end of the radius arm or below the end of the radius arm to adjust the caster of the vehicle wheel. The insulator, washer and nut are attached bacX to the radius arm.
The method of the present invention in the case of a stabilizer bar is to remove a stabilizer bar bracket that retains the bushing against the stabilizer bar body bracket and insert the device of the present invention either in front of or rearward , i, :
, , ~ ~L3161~5 of the stabilizer bar to correct ca~ter in the manner desired. The stabilizer bar bracket i8 then reattached to the stabili~er bar body bracket.
BRI~F_DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspectiYe view of an example of a suspen6ion system in which the device of the present invention i8 used.
Figure 2 is a cross-sectional view of the device of the present invention, the radius arm bushing and an end portion of the radius arm.
Figure 3 is a perspective view of the device of the present invention.
Figure 4 is a diagrammatical view of a radius arm illustrating how ca~ter is changed using the present invention.
Figure 5 i~ an exploded perspective view illustrating how the device of the present invention is inserted between an end portion of the radius arm and the radius arm bushing using a tool of the present invention.
Figures 6, 7 and 8 are end views illustrating the different thicknesses of the device of the present invention.
Figures 6a, 7a and 8a are front views showing different thicknesses of the device of the present invention.
Figure 9 is an end view of the tool of the present invention.
Figure 10 is a cross-sectional view of the tool of the present invention, the bushing with an end portion of the radius arm and a drill bit shown ~ 3 ~

whole illu~trating how the guide holes of the tool are used.
Figure 11 is a perspective view of a suspen-sion system having a portion of a ~abilizer bar disposed within a bushing that is ~ecured to the vehicle.
Figure 12 is an exploded perspective view of the stabilizer bar, stabilizer bar bushing, stabilizer bar bracket and stabilizer bar body bracket and the device of the present invention.
Figure 13 is a plan view o~ an alternative embodiment of the tool o~ the pre~ent invention.
Figure 14 is still another alternative embodiment of the tool of the present invention.
DETAILED DESCRIPTIO~ OF THE PREF~RRED EMBODIMENTS
The present invention i5 used to adjust cacter of a vehicle wheel in a suspension system such as is generally indicated by 10 in Figure 1. Only the left front wheel suspension system is ~hown with it being understood that a right front wheel suspension system is a mirror image of the left suspension system illustrated in Figure 1. The suspension system 10 is connected to a frame member 12 of a vehicle (not shown). The suspension system 10 includes an I-beam cross member 14. An axle 16 to which a vehicle wheel (not shown) is rotatably attached thereto is pivotally connected to the cross member 14 by a steering knuckle 17 having an axis 20. A steering system 18 through a series of tie rods pivots the axle about axis 20 through steering knuckle 17.

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The cross member ]4 is suspended from the frame member 12 by a coil spring 22 and shock absorber 24. A radiu~ arm 26 also holds the cross member 14 at one end portion 28 and is attached to the frame member 12 at another end portion 30.
The radius arm 26 is connected at the end portion 30 to the frame member 12 through a radius arm bushing 32 disposed in an arm bushing housing 34 that is securely welded or riveted to the frame member 12. Referring to Figure 2, the bushing 32 typically has a greater diameter forward section 36 and a smaller diameter rearward section 38 that iB
disposed within the bushing housing 34. The bushing contains an inner bore 40 through which the radius arm end portion extends. The radius arm end portion has a threaded end section 42 that extends beyond the bushing 32. The radius arm is retained in position by a nut 44 engaging the threaded end section 42. A
wa4her 46 and an insulator 48 are disposed between the nut and the bushing. A spacer 50 is also disposed between the insulator 48 and the bushing housing 34. A retainer 52 is positioned adjacent a front end of the bushing section 36~ The bushing 32 is made of a hard rubber for securely attaching the radius arm to the frame member while dampening any shocks that may be transmitted ~rom the wheels to the body of the vehicle.
Since the radius arm end portion 30 is riding within the bushing 32, the bushing 32 will wear over a period of time resulting in a certain amount of play developing. One primary cause for bushing wear is that the spring 22 sags over an :~ 3:~ 6~l~5 extended period of time. The sagging of æpring 22 causes accelerating wear in the bushing. The play caused by the sagging spring through t'he worn bushing 32 results in a deviation in caster. ~aster is the angle, as measured in degrees, that the steering knuckle axis i8 inclined from the vertical toward the front or rear of the vehicle. A small degree of positive caster improves directional stability and increases resistance to crosswinds or road surface deviation.
The device of the pre~ent invention, illustrated in Figure 3, eliminates the play developed between the radius arm end portion 30 and the bus'hing 32 and adjusts the caster angle. As illustrated in Figure 4, the axis 20 of the steering knuckle is 0 caster. Inclining the steering knuckle axis toward the front of the ve'hicle to line 20a provides a negative caster angle. Inclining the steering knuckle axis toward the rear of the vehicle provides a positive caster angle as identified by reference character 20b.
The device 52 of the present invention includes a longitudinal main body portion 54 being curved about a longitudinal axis 55. The main body portion 54 is generally arcuate in cross section. A
lip 56 is attached at one end and extends generally perpendicular to the longitudinal axis 55. The main body portion 54 of the device 52 has an inwardly curved surface area 60 that generally conforms to the outer curvature of the end portion 30 of the radius armO
As illustrated in Figure 2, the device 52 of the present invention adjusts caster without having :~ 3 ~ L S

to disconnect the radius arm from the bushing. The device 52 also eliminates any play that has developed due to wear of the bushing 32 ~rom contact between the bore 40 surfaces and the end portion 30 of the radius arm.
~ 8 best illustratecl in Figure 5, the nut 44 is threadably disengaged from the threaded end 42 of the end portion 30 of the radius ar~. The washer 46 and insulator 48 are also removed from the end portion 30. The device 52 is then ins~rted on an upper or a lower surface, depending on the caster adjustment required of the end portion 30.
Positioning the device below the end portion 30 moves the steering knuckle axis forward or to the position 20a of Figure 4. Positioning the device on a top surface of the end portion 30 moves the steering knuckle axis to the position 20b of Figure 4. The lip 56 acts as a stop and retaining means fox retaining the main body portion 54 in a selected position. In addition, the lip 56 may be used to facilitate removal of the device 52, if needed.
As illustrated in Figures 6, 7 and 8 (and also Figures 6a, 7a and 8a), the thickness of the longitudinal body 54, as depicted by arrows 62, 64 and 66 in Figures 6a, 7a and 8a, all respectively, can be varied. Varying the thickness of the longitudinal body 54 will vary the distance that the end of the radius arm is moved thereby varying the amount that the caster can be adjusted. The device 52 of the present invention is preferably provided as a set of devices with different thicknesses so that a device with the proper thickness is inserted to adjust the caster the desired degree.

13~611~

To facilitate insertion of the device 52 of the present invention, a tool 70, as illustrated in Figures S and 9 i8 provided. The tool 70 includes a front portion 72 and a rear portion 74 separated by a flange portion 88. The front portion 72 and the rear portion 74 are interchangable. The front portion 72 is inserted between the bushing 32 and the end portion of the radius arm 30, as illustrated in Figure 2, abutting the flange 88 against the bushing. Both the front portion 72 and the rear portion 74 have an inner curvature conforming to the outer surface curvature of the radius arm 30, and an outer surface curvature con~orming to the curvature of the inner surface of the bushing bore.
The tool 70 is provided with a plurality of guide holes 85 disposed within the Elange portion 88. If the space between the radius arm end portion 30 and the surface of the bore of the bushing 32 is not sufficient to accept a device 52 having a particular thickness, the guide holes 86 of the tool 70 are used to guide a drill bit 90 run by a drill 92 to remove amounts of rubber in the bushing. A series of holes are drilled on a diametrically opposite side from the point of insertion of the device 52 which permits the drilled bushing section to be compressed so that the device 52 is insertable between the end portion 30 and the bushing 32, as illustrated in Figure 10.
After the holes have been drilled in the bushing, the device 52 is inserted between the end :: .

portion 30 and the bushing 32. The lip 56 will prevent the device ~rom being inserted further than lS necessary.
After the device 52 is placed in position and the caster adjusted to the desired angle, the insulator 48 is placed against the spacer 50 and the washer 46 is placed against the insulator 48 and the nut 44 i5 threaded onto the threaded end section 42 of the radius arm.
The device of the present invention is also useful in correcting caster where ca~ter i~ affected by play developing between a stabilizer bar and bushing retaining the stabilizer bar and weakening of coil spring on strut. One such suspension i~
generally indicated at 100 in Figure 11. The suspension system shown in Figure 11 is a suspension system found in the Ford Escort. The suspension system includes a MacPherson strut 102 including coil spring 103 supporting each wheel on either side of the vehicle. The wheels are attached to steering knuckles 106 (only one being shown)~ The steering knuckle, in turn, i9 supported at one point by a control arm assembly 108 (only one being shown)~ The control arm as~emblies are connected by a stabilizer bar 110 that is secured to the vehicle by stabilizer bar body brackets 112.
Referring to Figure 12, the stabilizer bar 110 extends through a stabilizer bar bushing 114.
The stabilizer bar bushing 114 is held in place by a stabilizer bar bracket 116 that is attached to the stabilizer bar body bracket 112 by bolts 118 and 120 engaging nuts 122 and 124.

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.

6 ~

It will be appreciated that if play develops between the bushing 114 and the stabilizer bar 110, such that caster was affected, the bushing 114 had to be replaced. This required removing 'bracket 116, cutting the bushing 114 80 that the bushing is removed from the stabilizer bar and installing a new bushing that is provided in two halves (hereinafter referred to as a ~plit bu~hing). After the split bushing is put on a stabilizer bar, th~ bracket 116 is then reattached to the stabilizer bar body bracket 112 to hold the split bushing in place.
Using a device 126 of the present invention provides a simple method for eliminating the play between the stabilizer bar and the stabilizer bar bushing 114 and adjusting caster to a desired value.
The method of the present invention includes loosening bolts 118 and 120 enouyh so that the device 126 can be inserted between the bushing 114 and the stabilizer bar 110, either forward of the stabilizer bar 110 or rearward of the stabilizer bar 110.
Placing the device 126 in front of the stabiliæer bar 110 reduces caster. Placing the device 125 rearward of the stabilizer bar 110 increases caster.
After the device 126 i~ inserted in the desirad position, the bolts 118 and 120 are retightened, attaching the stabilizer bar bracket 116 once again to the stabilizer bar body bracket 112.
An alternative embodiment of the tool of the present invention is generally indicated at 130 in Figure 13. The tool 130 is a relatively flat plate 132 having at one end an aperture 134 with a diameter sufficient to accept, for example, the end portion of the radius arm 30 which is typically a 7/8 inch ' ~3~

diameter. In diametrically oppo~ite sides of the aperture 134 are two sets of a series of 1/8 inch guide holes 136 and 138, respectively. The tool 130 is used in a similar manner to ~he tool 70 illustrated in Figures 5, 9 and 10. The end portion 30 of the radius arm is inserted into the aperture 134 and then either guide holes 136 or guide holes 138 may be used to drill the bushing 32 as needed.
On an oppo~ite end of the tool 130 i8 located a curved Rlot 140 having a 7/16 inch radius with a plurality of 1/8 inch guide holes 142 located along the periphery of the slot 140. The slot 140 along with guide holes 142 is used to guide drilling holes in the bushing when the device of the present invention is used to adjust a stabilizer bar. The edge surface of the slot 140 is placed against the stabilizer bar along side the bushing, and the guide holes 142 are used to guide a drill bit to drill the bu hing, in a similar manner as shown in Figure 10.
One end of the tool 130 is used as a handle while utilizing the other end to guide drilling holes in the bushing.
In still another alternative ~mbodiment of the tool generally indicated at 144 in Figure 14, the tool 144 is a flat plate that includes an aperture 146 similar to aperture 134 of the tool in Figure 13. The apertur~ 146 includes two serie~ of guide holes positioned on diametrically opposite sides of the aperture 146. In addition, the tool 144 includes a series of curved slots 152, 154 and 156. Each curved slot has a plurality of 1/8 inch ~uide holes associated therewith. The curved slot 152 has guide ~31611~

holes 15~ disposed along the periphery of the slot.
Similarly, the curved slot 154 has a plurality of guide holes 160 disposed along the periphery of the slot 154. The slot 156 also has a plura~ity of guide holes 162 as~ociated therewith. The slots 152~ 154 and 156 each have a different radius and are used for a stabilizer bars of differe!nt diameters, in the same manner that curved slot 140 is used of Figure 13. In the working embodiment, the slot 152 will accept a bar of 1 inch diameter, the slot 154 will accept a bar of 7/8 inch diameter, and the slot 156 will accept a bar of 1 l/2 inch diameter.
In summary, the present invention provides a solution for easily correcting caster in a vehicle wheel having either a radius arm or stabilizer bar retained within a bushing that can be worn. In addition, the present invention provides a method for correcting caster due to a worn bushing without having to disconnect the radius arm or the stabilizer bar.
Although the present invention has been described with rPference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

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Claims (15)

1. A device for adjusting caster of a wheel attached to a vehicle by a suspension system having a rod member affecting the caster of the wheel, a portion of the rod member being disposed within a bushing attached to the vehicle, the device comprising:
a longitudinal member having an arcuate cross section for insertion between the portion of the rod member disposed within the bushing and the bushing.
2. The device of claim 1 wherein the curved member has a lip portion.
3. The device of claim 1 wherein the curved member has an inner curved surface generally conforming to a surface of the portion of the rod member within the bushing.
4. A tool used for inserting the device of claim 1 between the bushing and wherein the rod member is a radius arm having an end portion within the bushing, the tool comprising:
a handle portion; and a tool engaging portion having a curved edge surface for engaging the rod member and a plurality of guide holes disposed along the curved edge.
5. The tool of claim 4 wherein the tool further includes a flange portion and the guide holes are disposed within the flange portion.
6. A method for adjusting caster of a wheel attached to a vehicle having a rod member affecting caster, the rod member having a portion disposed within a bushing, the method comprising:
inserting between the rod member and the bushing a shim along one side of the rod member to adjust the caster of the wheel.
7. The method of claim 1 wherein the shim is configured to conform to an outer surface of the rod member.
8. The method of claim 6 and wherein the rod member is a radius arm and further including the steps of:
disengaging a nut from an end of the radius arm disposed within the bushing prior to insertion of the shim; and placing the nut back on the end of the radius arm after the shim is inserted between the radius arm and the bushing.
9. The method of claim 8 and further including the step of:
removing washers and insulators prior to inserting the shim between the radius arm and the bushing and placing back any washers or insulators after the shim has been inserted.
10. A method for adjusting caster of a wheel attached to a vehicle having a stabilizer bar that affects caster, the stabilizer bar having a portion disposed within the bushing, the method comprising:
inserting between the stabilizer bar and the bushing a shim along one side of the stabilizer bar to adjust the caster of the wheel.
11. A device for adjusting alignment of a wheel attached to a vehicle by a suspension system having a rod member affecting the caster of the wheel, a portion of the rod member being disposed within a bushing attached to the vehicle, the device comprising:
a longitudinal member having an arcuate cross section for insertion between the portion of the rod member disposed within the bushing and the bushing and further including stop means fixedly attached to the longitudinal member for selectively positioning the member longitudinally between the bushing and the rod member.
12. The device of claim 11 wherein the rod member has a curved surface and wherein the member has an inner curved surface generally conforming to the curved surface of the portion of the rod member within the bushing.
13. The device of claim 11 wherein the stop means includes a lip attached to the longitudinal member, the lip extending substantially perpen-dicularly with respect to the longitudinal axis of the member.
14. The device of claim 11 and further includ-ing means for facilitating removal of the longitudinal member form between the bushing and rod member, the means for facilitating being attached to the longitudinal member.
15. The device of claim 14 wherein the means for facilitating includes a lip attached to the longitudinal member, the lip extending substantially perpendicularly to the longitudinal axis of the member.
CA000574035A 1987-08-07 1988-08-05 Device for adjusting caster Expired - Fee Related CA1316115C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US083,564 1979-10-11
US8356487A 1987-08-07 1987-08-07

Publications (1)

Publication Number Publication Date
CA1316115C true CA1316115C (en) 1993-04-13

Family

ID=22179158

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000574035A Expired - Fee Related CA1316115C (en) 1987-08-07 1988-08-05 Device for adjusting caster

Country Status (2)

Country Link
AU (1) AU610623B2 (en)
CA (1) CA1316115C (en)

Also Published As

Publication number Publication date
AU2042888A (en) 1989-02-09
AU610623B2 (en) 1991-05-23

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