SPECIFICATION Background and Description of the Invention

1. Field of the Invention

The present invention relates generally to truck suspension systems and, more particularly, to a laterally adjustable suspension control system incorporating a rigid V-shaped restraint or a Watt linkage that is laterally adjustable with shims.

2. Discussion

Heavy duty truck suspension designs often feature a V-shaped rigid restraint known as a V-rod, A-aπn or V-link, attached between the truck axle housing and the side frame rails. In such an installation, the V-rod is typically oriented with its vertex attached to the top center of the axle housing while the distal end of one arm is attached to one of the side frame rails and the distal end of the other arm is attached to the opposing side frame rail. The V-rod thus configured provides both lateral and longitudinal control for the truck axle.

Ideally, the length of the V-rod arms are such that upon assembly of the suspension, the axle is laterally aligned with the side frame rails so that the frame is centered between or over the wheels on the opposing ends of the axle. During manufacture of the axle housing and the various suspension components, including the V-rod restraint, however, part dimension variances often occur so that when the suspension is assembled, the frame is somewhat laterally off the center of the axle. Furthermore, if the suspension utilizes tandem axles, the two axles may not be aligned laterally with each other. When the axles are out of lateral alignment with the truck

frame and/or each other, the suspension is said to not be /•tracking" properly. This situation results in excessive and uneven tire wear and other related problems.

Prior art suspension systems have addressed this tracking problem by utilizing threaded rods as the arms of the V-rod with fittings at the V-rod vertex and at each distal end. As such, the length of each arm of the V-rod could be adjusted by turning each threaded rod thus moving the vertex fitting and a distal end fitting either towards or away from each other. By adjusting the length of each arm of the V-rod, the suspension could be made to track properly. In other words, the axles could be brought into laterally alignment with the frame and each other. While such an approach is effective, readjustment is sometimes necessitated as the threaded rods may shift slightly during use of the truck. Furthermore, the manufacture of V-rods featuring threaded arms with vertex and distal end fittings is more complex and expensive than if just a one- piece V-rod were produced. Alternatively, some truck suspension designs utilize a Watt linkage in place of a V-rod. Such Watt linkage assemblies utilize lateral rods oriented with their inner ends attached to a Watt link which is in turn attached to the top center of the axle housing. The distal end of one lateral rod is attached to one of the side frame rails while the distal end of the other lateral rod is attached to the opposing side frame rail. As with V-rods, lateral adjustment of the Watt linkage assembly is sometimes necessary. It is, therefore, an object of the present invention to provide a laterally adjustable suspension control system that is resistant to shifting and thus stays adjusted.

Another object of the invention is to provide a simple and inexpensive laterally adjustable suspension control system.

Summarv of the invention The present invention is directed to a laterally adjustable system for positioning and controlling the lateral relationship between a vehicle frame and one or more axles disposed beneath the frame, where the frame includes a pair of fore-and-aft extending side rails and at least one cross member extending therebetween. A rigid V-shaped restraint is anchored at its vertex to the truck axle. A pair of restraint mounting assemblies connect the distal ends of the divergent rods of the restraint to the side rails with each mounting assembly being partially supported on the frame cross member. Shims may be selectively inserted between the mounting assemblies and the adjacent side rails to adjust the lateral position of the restraint relative to the truck frame thus laterally aligning the truck frame with the axle and the truck wheels. Alternatively, a Watt linkage may be substituted for the rigid V-shaped restraint. For a more complete understanding of the nature and scope of the invention, reference may now be had to the following detailed description of embodiments thereof taken in conjunction with the appended claims and accompanying drawings.

Brief Description of the Drawings FIG. 1 is a diagrammatic top plan view of an embodiment of the invention that utilizes fabricated restraint mounting assemblies with an axle and a drive shaft shown in phantom;

FIG. 2 is a fragmentary isometric view on enlarged scale showing details of the embodiment shown in FIG. 1;

FIG. 3 is a fragmentary isometric view of a prior art suspension system utilizing a V-rod upon which the invention may be used; FIG. 4 is a diagrammatic top plan view of an embodiment of the invention that utilizes cast restraint mounting assemblies with an axle and a drive shaft shown

in phantom ;

FIG. 5 is a fragmentary isometric view on enlarged scale showing details of the embodiment shown in FIG. 4; FIG. 6 is a fragmentary isometric view of a prior art suspension system utilizing a Watt linkage upon which the invention may be used.

Description of the Preferred Embodiment Referring to FIGS. 1 and 2, the rear portion of a vehicle frame, such as that of a heavy duty truck, is indicated generally at 3. The frame comprises fore and aft extending side rails 5-5 and cross member 7. Frame 3 is supported upon ground wheels, not shown, by an axle, indicated generally at 15 in phantom, and a suspension not shown. The rear portion of the drive shaft is shown in phantom at 16. It is understood that the suspension controls the yaw position of axle 15. One type of suspension that may be used is the Hendrickson six rod, shown in FIG. 3. The term "axle" as used herein comprises both the axle housing and the axle itself.

An embodiment of the laterally adjustable system of the present invention is indicated generally at 17 in FIGS. 1 and 2. As shown in FIGS. 1 and 2, a rigid V- shaped restraint, indicated generally at 21 is connected between axle 15 and each one of the two side rails. This configuration provides both lateral and longitudinal control for axle 15. Restraint 21 comprises an apex 23 and divergent rods 25-25 forming a fixed angle of o< so that the distal ends of divergent rods 25-25 span a width that is narrower than the lateral distance between frame side rails 5-5, as shown in FIG. 1.

Apex 23 of restraint 21 is connected to the top of the differential portion 27 of axle 15 via a conventional ball and socket mount 28 (FIG. 2) .

Alternative mounting methods that allow movement between axle 15 and restraint 21 could be used instead of ball and

socket mount 28.

As FIGS. 1 and 2 show, at the distal ends of divergent rods 25-25 of restraint 21 are eye formations 31-31. Inserted through eye formations 31-31 are bushings 33-33 and pins 35-35. Pins 35-35 are bolted to fabricated restraint mounting assemblies, indicated generally at 37- 37, with bolts 38 so that restraint 21 may pivot through a limited arc above and below the plane formed by frame 3. As shown in FIGS. 1 and 2, each fabricated restraint mounting assembly 37 is comprised of diagonal plate 39, side plate 40, flange plates 41 and corner plate 42. All of these plate components are welded together to form each fabricated restraint mounting assembly 37.

Fabricated restraint mounting assemblies 37-37 are welded to cross member 7 as indicated at W-W in FIG.

2. Shims 43-43 may be welded between fabricated restraint mounting assemblies 37-37 and side rails 5-5 as indicated at W'-W'. This allows for lateral adjustment of restraint 21. By choosing the proper width of shims 43-43, or choosing to omit them from one side all together, frame 3 may be centered between the vehicle wheels.

FIGS. 4 and 5 show an alternative embodiment of the invention in which cast restraint mounting assemblies 51-51 are substituted for the fabricated restraint mounting assemblies 37-37 of FIGS. 1 and 2. As shown in FIGS. 4 and 5, cast restraint mounting assemblies 51-51 are bolted to cross member 53 and side rails 55-55 of the frame, indicated generally at 56, with bolts 57 and nuts 59. Shims 61-61 may be placed between cast restraint mounting assemblies 51-51 and side rails 55-55. As with the embodiment shown in FIGS. 1 and 2, by choosing the proper width of shims 61-61, or choosing to omit them from one side all together, frame 56 may be centered between the vehicle wheels. Finally, another alternative embodiment of the invention may be used to laterally position a suspension that utilizes a Watt linkage. An example of such a

suspension is indicated generally at 71 in FIG. 6. Lateral rods 73-73 are pivotally connected at their inner ends to the opposing ends of Watt link 75 and at their outer ends to side brackets 81-81. Watt link 75 is pivotally connected at its center to axle bracket 83.

Axle bracket 83 is connected to axle 85. Side brackets 81-81 are bolted to frame side rails, shown in phantom at 87-87. Shims, indicated in phantom at 91-91, may be inserted between side brackets 81-81 and frame side rails 87-87 so that the latter may be centered between the vehicle wheels, one of which is indicated in phantom at 93.

Having described the invention generally in detail in connection with the drawings, including presently preferred embodiments thereof, those skilled in the art will be able to practice the invention either according to the embodiments disclosed or according to other embodiments without departing from the spirit and scope of the appended claims.