VEHICLE SUSPENSION SYSTEM

Abstract

A vehicle suspension system which includes a least one suspension airbag interposed between a vehicle axle and a vehicle body and a supplementary airbag positioned on a fixed support in the suspension system and extending to a structural member of the suspension system, the arrangement being such that with the suspension airbag inflated and the supplementary airbag deflated, the suspension system operates normally, and with the suspension airbag deflated and the supplementary airbag inflated, the suspension system is lifted with a consequent lifting of the axle, to bring its road wheels clear of the road surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention is illustrated by way of example only in the accompanying drawings in which:

FIG. 1 is a schematic representation of a tractor vehicle of the prior art with twin rear axles;

FIG. 2 shows a part of FIG. 1 to a larger scale, with parts removed for clarity;

FIG. 3 is a perspective view of a support member for a supplementary airbag;

FIG. 4 is an underneath plan view of FIG. 3;

FIG. 5 is a side elevation of FIG. 3;

FIG. 6 is a perspective view of the torque box of the vehicle suspension system;

FIG. 7 is an underneath plan view of FIG. 5; and

FIG. 8 shows the assembly of the torque box and supplementary airbag of one embodiment of the invention.

Claims

1. A vehicle suspension system comprising at least one suspension airbag interposed between a vehicle axle and a vehicle body and a supplementary airbag positioned on a fixed support in the suspension system and extending to a structural member of the suspension system, the arrangement being such that with the suspension airbag inflated and the supplementary airbag deflated, the suspension system operates normally, and with the suspension airbag deflated and the supplementary airbag inflated, the suspension system is lifted with a consequent lifting of the axle, to bring its road wheels clear of the road surface.

2. A vehicle suspension as in claim 1, wherein the structural member is a torque box having a mounting frame.

3. A vehicle suspension system as in claim 1, wherein an axle is attached to an A-frame to assist in the maintenance of an axle in its required position, and the supplementary airbag is positioned below the A-frame in close proximity to the axle, and the A-frame pivotally connected to the vehicle frame, so that as the or each airbag of the suspension system is deflated, the supplementary airbag below the A-frame is inflated, causing the axle to lift and bring its road wheels clear of the road surface.

4. A vehicle suspension system comprising a torque means mounted on and extending between the vehicle structure and an axle, said torque means including a generally box-like structure, at least one suspension airbag located between the vehicle structure and the axle, a support means attached to the vehicle structure and extending below the box-like structure, and a supplementary airbag extending between the support and the box-like structure, the arrangement being such that with a vehicle having a double or triple axle aggregate or bogie, operating conventionally and carrying its load, all wheels on all of the axles are in ground contact, and with e.g. the vehicle running empty or with a load significantly less than the maximum permitted load, at least one axle of a multi-axle aggregate or bogie can be raised, by deflating the suspension airbag or bags and inflating the supplementary airbag, to cause the box-like structure to lift and as a consequence cause the said axle or axles to lift, to bring its wheels clear of the road.