Background and Description of the Invention
This invention relates, generally, to suspensions for light duty trucks and similar vehicles. The suspensions make use of four air springs and two single leaf springs together with shock absorber systems. More particularly, the invention relates to such suspensions which will replace conventional vehicle axle suspensions of the type combining a leaf spring pack and a shock absorber system mounted on and below a fore-and-aft extending chassis frame member on each side of a vehicle, and with each leaf spring pack and its shock absorber system being attached to the adjacent end of an axle.
A suspension of the present invention can either be installed as original equipment on a vehicle such as a light duty truck or it may be installed to replace a conventional leaf spring pack and shock absorber system. In either case, the suspension of the present invention is unique in that it makes maximum use of (1) certain existing or already in place components used in a conventional vehicle axle suspension of the type combining a leaf spring pack and a shock absorber system and (2) existing air springs and related components which are standard in suspensions of the type that utilize air springs.
In the suspensions of the present invention single leaf springs provide the primary support for the load due to the empty vehicle and resist side thrusts and driving and/or braking torque end thrusts applied from the vehicle's axle. The four air springs provide the primary support for the portion of the total load which exceeds the load due to the vehicle when empty.
In view of the foregoing summary of the invention, it will be seen that the object thereof, generally stated, is the provision of a suspension for light weight trucks and similar vehicles that makes maximum use of conventional and standard components and known vehicle suspension designs and technology to provide a new, low-cost suspension system for light duty trucks and the like that addresses the user's concern for a softer ride through the entire range of empty and loaded vehicle conditions.
A further object of the invention is to incorporate in the suspensions new known height control systems which provide a constant ride height thereby requiring less rear wheel to fender clearance and permitting easier headlight aiming.
Certain other objects of the invention will be apparent to those skilled in the art from the following detailed description of the presently preferred embodiment taken in conjunction with the accompanying drawings wherein:
Brief Description of the Drawings
FIG. 1 is an isometric view of a suspension embodying the present invention for one side of a vehicle; and
FIG. 2 is a side elevational view of the suspension of FIG. 1.
Referring to the drawings, the suspension is indicated therein generally at 5. It will be understood that this suspension is duplicated on the opposite side of the vehicle. The active or functional components of the suspension 5 comprise two air springs 6--6 and a single leaf spring 7. The single leaf spring 7 is provided with eyes 8--8 on opposite ends which are shackled to standard or existing shackle attachments 10 and 11 such as used for a leaf spring pack. The shackle attachments or mountings 10 and 11 may have already been mounted on the fore-and-aft frame member 12 if the suspension 5 is being installed to replace an existing leaf spring pack suspension. If the suspension 5 is an original equipment suspension, then the shackle attachments 10 and 11 will be mounted in the locations where they would normally be mounted for installing a conventional leaf spring pack.
A pair of air spring support brackets 13--13 are mounted on the side of the chassis frame member 12 in locations that are fore-and-aft of the vehicle axle housing 16 (FIG. 2) and the mid-portion of the single leaf spring 7. The attachment of each air spring 6 to its support bracket 13 is achieved by way of stud 14. The lower end of each air spring 6 is attached to the single leaf spring 7 by a U-shaped clip 15.
The mid-portion of the single leaf spring 7 is attached to the adjacent end of an axle or axle housing 16 by means of a conventional axle attachment assembly indicated generally at 17. This assembly comprises a bottom plate 18 suitably apertured to receive the lower ends of shackle bolts 20--20 the bight portions of which clamp over a steel spacer 21 which rests on top of the single leaf spring 7. Preferably, the spacer 21 has grooves 22 at its opposite ends into which the bight portions of the shackles 20 fit. The vertical thickness of the spacer 21 is such as to compensate or equal the difference between the thickness of a replaced leaf spring pack and the thickness of the single leaf spring 7. Thus, the existing or standard actual attachment 17 used with a leaf spring pack can be used in the suspension 5.
A conventional shock absorber 23 and shock absorber system as used with a conventional leaf spring pack suspension may be retained or used in the suspension 5. The shock absorber 23 is shown attached to an arm 24 extending integrally from the bottom plate 18.
As mentioned above, the suspension 5 may be installed as part of the original equipment of a vehicle such as a light truck or it may be installed as a replacement for an original equipment suspension in the form of a leaf spring pack and shock absorber system.
The single leaf springs 7 (one on each side) will be of such design as to be the primary support for the load on the axle 16 when the vehicle is in its empty or unloaded condition. The four air springs 6 (two on each side) will provide the primary support for the load on the axle 16 over and above the empty weight of the vehicle. The compressed air for the air springs 6 will be supplied by an electric motor driven air compressor (not shown) in accordance with known designs.
Preferably, the suspension 5 is provided with a height control system of known type which is indicated diagrammatically at 25 (FIG. 2). The system 25 comprises a leveling valve 26 of known type having an actuating lever 27 which is pivotally connected to the upper end of a link 28. The bottom end of the link is pivotally connected to a mounting bracket 30 extending from the top of the spacer 21. The system 25 (one on each side of the vehicle) operates in known manner to maintain the chassis frame member 12 at a predetermined height. This provides Q for a constant ride height and permits reduced rear wheel to fender clearance while headlight aiming becomes easier. Air is supplied to or vented from the air springs 6 by operation of the leveling valve 26 in known manner.
The components of the suspension 5 are known and already in use on suspensions in commercial use except for the single leaf spring 7 and the loaf-like spacer 21. Thus, kits for suspensions of the present invention are essentially readily available and installable at low cost making full use of known technology.