IES980386A2 - A tandem axle suspension system - Google Patents

Description

_________η IE 980386 \ LODGED] - i - "A Tandem Axle Suspension System·' This invention relates to a tandem axle suspension system.

Independent suspension of the wheels of a vehicle has many advantages in terms of vehicle mobility, handling and ride quality. One disadvantage for vehicles with multiple 5 (three or more) axles is that in some circumstances, for example in traversing ramps or bumps or when the load on the vehicle is unevenly distributed, the load distribution between the axles may vary. This uneven loading can cause problems in some circumstances.

The present invention is directed towards overcoming these problems .

According to the invention, there is provided a tandem axle suspension system for mounting a pair of wheels on a vehicle chassis comprising a pair of independently sprung 15 wheels mounted in tandem on the chassis with load equalisation means mounted on the chassis and connected between the wheels.

In a particularly preferred embodiment, said means is a ·"” .........—Tl walking beam pivotally mounted on the chassis and S connected between the wheels. i ξ I t 3 In one embodiment the walking beam extends between Z CC I suspension springs on each wheel. ΊεΟ & it» 2 Q o < 1 : <2 oo M In an alternative embodiment, the walking beam is mounted Z3 PsJ £ on! between axle housings on which each wheel is mounted. t 1 s In a further embodiment, the wheels are mounted on a sub- ί frame which is pivotally mounted on the chassis. 3 __ " ——— (NT CL bN-JC'Cr b/c/) BNSDOCID: - 2 - IE 980386 The pivot mounting of the walking beam or subframe on the chassis may be carried out in a number of ways. For example, the pivot mounting may comprise a pivot pin. Alternatively, the pivot mounting may be provided by an 5 elastomeric pivot element.

The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings in which:- 10 Fig. 1 is a schematic elevational view of a tandem axle suspension system according to the invention; and Fig. 2 is an end elevational view of the axle suspension system.

Referring to the drawings, there is illustrated a tandem axle suspension system according to the invention indicated generally by the reference numeral 1. The system 1 is for mounting a pair of wheels 2 in tandem on a vehicle chassis 3. Each wheel 2 is mounted by 20 independent suspension 4 on the chassis 3. Suspension springs 5 associated with each wheel 2 are interconnected at their upper ends by a walking beam 6 which is pivotally mounted by a pivot pin 7 on the chassis 3.

The independent suspension 4 includes an upper suspension 25 control arm 10 and a lower suspension control arm 11. An inner end of each suspension control arm 10, 11 is pivotally mounted on a differential housing 12 which in this case forms a transverse chassis structural member. Outer ends of the suspension control arms 10, 11 support 30 a wheel hub 14. A drive shaft 15 extends between the differential housing 12 and each wheel hub 14.

BNSDOCID: - 3 - IE 980386 In use, pivotal movement of the walking beam 6 on the chassis 3 evenly distributes the load carried on the chassis 3 between the wheels 2. it will be appreciated that instead of mounting the 5 walking beam between the springs, it may alternatively be connected between axle housings which carry the suspension wishbone associated with each wheel 2.

It is also envisaged that in some cases that the axle and spring associated with each wheel may be mounted on a sub-10 frame which in turn is pivoted on the chassis 3 in similar fashion as the walking beam.

The invention is not limited to the embodiment hereinbefore described which may be varied in both construction and detail.

CRUICKSHANK & CO., 15 ab\spec1-9E>\land*m.apr BNSDOC1D: