GB2233941A

GB2233941A - A transverse leaf spring suspension for a vehicle wheel

Info

Publication number: GB2233941A
Application number: GB9012978A
Authority: GB
Inventors: Adrian Seymour Tucker-Peake
Original assignee: GKN Automotive Inc
Current assignee: GKN Driveline North America Inc
Priority date: 1989-06-12
Filing date: 1990-06-11
Publication date: 1991-01-23
Also published as: DE4018459A1; KR910000402A; GB9012978D0; ES2024770A6; AU5471590A; JPH0316819A; CA2012324A1; SE9001802D0; FR2648086A1; CN1048006A

Abstract

A vehicle wheel suspension that includes a transversely extending leaf spring 22 with free ends that terminate adjacent to wheel support knuckles 16, has a flexible stirrup 30 interconnecting the free end of the leaf spring to the wheel knuckle. Thus the sprung mass is transferred to the wheel by the flexible stirrup, which has near zero stiffness in the flexible planes of the stirrup. A method of compensating for stirrup vertical sidewall length variances is possible by inserting shims between the layers of the stirrups. The stirrup 30 is made of elastomeric material with continuous filamentary reinforcement. <IMAGE>

Description

i 1 SUSPENSION FOR WHEEL OF VEHICLE The present invention relates to a

suspension for a vehicle such as a passenger automobile. More particularly, the invention involves a suspension that is suitable for the rear wheels of a passenger automobile, although it will be appreciated that the invention would have application to other vehicles.

Automotive vehicle suspension systems utilising one or more transverse leaf springs are well known and such systems provide for independent movement of each wheel connected thereto. With the advent of front wheel drive automobiles, it is advantageous to provide for independent movement of each one of the rear wheels. In automobile suspension systems most widely used, the resiliency is usually provided by coil springs that are operative between pivoted arms and the vehicle structure at positions remote from the arm pivots. Such an arrangement utilising coil springs has a disadvantage in that the structure of the vehicle adjacent the wheel has to be designed to provide space to accommodate the coil springs and to take the loads that arise at the points where the springs are connected to the vehicle structure. The present invention employs a unitary leaf spring arrangement, thus avoiding the disadvantages associated with prior art coil spring suspension systems.

The prior art reveals a wide variety of suspension systems that have been used on one type of vehicle or the other. In general, most prior art devices provide for a fairly rigid attachment between the wheel and its spring.1 biasing system.

k-- 12 2 The present invention is an improvement over the vehicular spring suspension system shown and described in US Patent No. 4,281,851 entitled "Spring Suspension" issued August 4, 1981 to Vernon Brandt. The above referenced patent shows a spring suspension system for mounting a spring member to an axle assembly and a vehicle body. In particular, each one of the vehicle rear wheels is supported by a single leaf spring that is aligned longitudinally with respect to the vehicle chassis. A king pin, and associated suspension hardware, is positioned at the centre of the leaf spring for the mounting of a rear wheel. As shown in Figure 1 of the US Patent 4,281,851, the front end of the leaf spring 3 has an end portion 5 that is cantilevered vertically normal to the longitudinal extent of the leaf spring 3. The vertically aligned end portion 5 reacts with a front bracket that is bolted to the vehicle chassis, thus fore and aft wheel loads are transferred to the vehicle proper. The front end of the leaf spring 3 rests on a transversely aligned bolt that is carried by the front bracket. The back end of the leaf spring 3 is supported by a transversely aligned bolt carried by a rear bracket. Thus, the rear bracket and its associated transversely aligned bolt carries only vertical loads imposed on it by the back end of the leaf spring 3.

The present invention differs from the above set forth structure which incorporates pivotal connections at the front and back of each spring to facilitate spring removal and maintenance. The present invention is concerned with a stiffness disconnection or decoupling so that the vehicle will have a refined operation.

In US Patent No. 4,619,466 entitled "Wheel Suspension" issued October 28, 1986 to Walter Schaible et al, a motor 3 vehicle wheel suspension employing a transversely oriented leaf spring is shown and described. The leaf spring is manufactured from a composite fibre material and is especially adapted for a front wheel suspension system. The leaf spring is positioned between two transverse arms that are attached to a wheel support mechanism. The free end of the leaf spring is clamped to the wheel support mechanism by an elastomeric lined clamp. As the end of the spring flexes, the spring will move in a transverse direction through its clamp support mechanism. The clamp, however, causes the spring end to follow it through vertical movement as well as rotational movement. Thus, a torque is applied to the free end of the spring. Not only must the spring described in US Patent No. 4,619,466 support the sprung mass but, also, it must resist longitudinally applied bending loads coupled with wheel induced torque movements.

The present invention is an improvement over the suspension system described above in that little or no torque is transmitted to the free end of the spring. The attachment to the end of the spring enables the spring to support the sprung mass while affording the desired flexibility in the necessary planes.

An additional spring support concept is presented in US Patent No. 4,614,359 entitled "Vehicle Wheel with Height Adjustment" issued September 30, 1986 to Donald G.

Lundin et al. A transverse leaf spring is positioned between the sprung and unsprung masses of the vehicle at the rear thereof. The leaf spring is formed of composite material such as fibreglass reinforced resin and is positioned between a pair of lateral control arms. The control arms are PiVO-JILIY connected Lo the vehicle chassis and also to a wheel support knuckle. The wheel 4 stability is.further assured by a trailing link that is attached to the chassis at one end and attached to the wheel support knuckle at the other end. The end of the leaf spring terminates in the vicinity of the support knuckle where it rests on a bolt carried by the support knuckle. The bolt shank can be adjusted thus raising or lowering the end of the leaf spring relative to the knuckle. A suitable trim, or attitude, and height for the vehicle is attained as the vehicle sprung mass is raised or lowered by means of the adjustment bolt. The leaf spring cantilevered ends carry no load except a vertical load and some torque is induced in the leaf spring because of the contact made by the support bolt on the underside of the leaf spring end.

is The spring support concept of the present invention differs from the above set forth spring support system in that the end of the spring carries the sprung mass of the vehicle and at the same time wheel jounce has little effect on the spring except to induce bending therein as 20 the unsprung mass moves relative to the sprung mass.

A primary object of the present invention is to provide a vehicle wheel suspension system that has the desired resiliency, yet is simple and inexpensive to manufacture. Desirably the invention should also satisfy 25 one or more of the following objectives:- to provide an interconnection between a spring and a wheel suspension that has a variable flexibility depending on the direction of movement of the wheel and the amount of displacement; to provide for trim height adjustment of the vehicle through the interconnection between the spring and the wheel suspension assembly; to provide an attachment to a composite structure JI 1 spring that imparts a minimum amount of torsion to the spring; to reduce the complexity and number of parts that are utilised in a vehicle suspension system; to provide a spring support stirrup that possesses a high degree of inelasticity in one direction yet having almost zero initial stiffness in other directions; to provide an attachment to a qomposite material spring that increases the life of the spring; to provide vehicular trim adjustments without disassembly of the interconnection between the spring and the wheel support structure.

According to one aspect of the present invention, we provide a vehicle suspension structure for controlling the movement of a wheel support assembly, of a vehicle having wheels and a chassis, said vehicle suspension structure comprising:,at least one wheel support knuckle pivotally attached to a portion of said vehicle chassis; 20 a wheel spindle on said at least one wheel support knuckle, said wheel spindle being disposed substantially horizontally and transversely with respect to said vehicle chassis, one of said wheels being mounted on said wheel spindle for carrying a proportionate amount of the mass of said vehicle; support means connected to and extending from said at least one wheel support knuckle to react a load applied in a substantially vertical direction; a leaf spring disposed to extend transversely of said vehicle adjacent said at least one wheel support knuckle; and resilient means interconnecting said support means and an end of said leaf spring whereby a portion of said -1\ 6 vehicle sprung mass is communicated in a resilient manner to said one of said wheels.

Preferably, the leaf spring of the present invention is fabricated from a composite, fibre reinforced plastic material. A leaf spring so manufactured has the advantage of being of light weight, for which composite material leaf springs are well known. Because of the material selection, the leaf spring can be designed to meet suspension requirements of any particular vehicle, particularly with respect to parameters such as the variation in thickness or width of the spring along its length. The use of the leaf springs of fibre reinforced plastic material enables the overall spring weight to be reduced.

A flexible stirrup, preferably formed as a loop, couples each free end of the leaf spring to the adjacent wheel support structure. The stirrup is arranged to provide essentially vertical suspension between the leaf spring and the wheel support structure. The stirrup is intended to be a lightweight, low maintenance connection that does not twist the spring yet affords the desired flexibility in the necessary planes. Simple height adjustment as well as the ability to accommodate small twist or steer angles are also attributes of the present invention.

Further objects and advantages of the present invention will become apparent from the following description and the appended claims, reference being made to the accompanying drawings forming a part of this specification, wherein like reference numerals are used through the various views to designate like parts.

1 7 Figure 1 is a perspective view of a left rear vehicle wheel that shows the interconnection between a leaf spring and a wheel support assembly; Figure 2 is a broken away perspective view of the interconnection between a lower control arm and a leaf spring; Figure 3 is a sectioned view of the flexible link or stirrup utilised in the present invention; Figure 4 is a broken away schematic side view of a lower control arm, a stirrup and adjustment clips; Figure 5 is a sectioned view of a variation in the flexible link connection between a leaf spring and adjacent wheel support structure; Figure 6 is a sectioned view of another variation of a stirrup connection between a leaf spring and a wheel support structure; and Figure 7 is a sectioned view of a telescoped stirrup with adjustment wedges positioned in the vertical side walls thereof.

It is to be understood that the present invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways within the scope of the claims. Also, it is to be understood that the phraseology and terminology utilised herein is for- the purposc- of description and not of limitation.

8 Referring now to the drawings and more particularly to Figure 1, there is illustrated a perspective view of a left rear vehicle wheel assembly as viewed from the rear of the vehicle. The overall wheel assembly is identified by the numeral 10. A longitudinal axis 12 runs from front to rear of the vehicle on which the overall wheel assembly 10 is mounted. As is common to most vehicles, a transverse axis 14 runs perpendicular to the longitudinal axis 12. As shown, the transverse axis 14 coincides with the axis of rotation of the vehicle wheels. A wheel support knuckle 16 has cantilevered outwardly therefrom a wheel spindle 18 that is adapted to receive a wheel such as is identified by the numeral 20. The wheel spindle 18 is perpendicular to the longitudinal axis 12 of the vehicle. While it is not shown in the drawings, it is common to enhance the overall suspension by attaching a MacPherson shock strut to the support knuckle 16 and attaching the other end to the vehicle chassis. In addition, the support knuckle 16 is also pivotally attached to the vehicle chassis, e.g. by a control arm, so that its greatest degree of movement can occur in a vertical direction. The shock strut is not utilised as a vehicle weight carrying device but rather to attenuate the jounce motion caused by the wheel 20 as it moves over a roadway surface. The main mass of the vehicle, sometimes referred to as the sprung mass, is supported by a spring arrangement consisting of one or more springs positioned generally at each wheel of the vehicle. Figure 1 depicts a leaf spring 22 that is oriented parallel to the transverse axis 14 of the overall wheel assembly 10. For the purposes of the present invention, the leaf spring 22 can be made of steel or the leaf spring 22 can be made of composite fibre reinforced plastic material such as unidirectional glass fibres encased in polyester or epoxy resin. The leaf spring 22 9 is generally fabricated in such a length so as to span the transverse width of the vehicle. A slight camber is fabricated in the leaf spring 22 during the initial layup and moulding thereof. The camber helps to offset the sprung mass. For purposes of simplicity, the leaf spring 22 shown in Figure 1 has a constant cross-sectional area over its length; however, a spring could be utilised that varies in width and thickness.

The leaf spring 22 is anchored (not shown) to the chassis of the vehicle near the longitudinal centre line thereof.

The leaf spring 22 has its ends 24 cantilevered in a direction toward the vehicle wheels 20. As can be seen in Figure 1, the spring end 24 terminates short of the support knuckle 16. The support knuckle 16 is generally coupled to the vehicle with one or more struts that keep the wheel 20 tracking along the longitudinal axis 12.

The support knuckle 16 also has a cantilevered support plate 26 attached as an integral part thereof. The support plate 26 has a generally planar top surface, although cylindrical curvilinear surfaces would work equally well with the present invention. An upstanding lip or flange 28 is formed on the end of the support plate 26.

The overall geometry of the support knuckle 16 and the end 24 of the leaf spring 22 is arranged so that the end 24 is positioned below and in spaced apart relationship with respect to the support plate 26. The end 24 of the leaf spring 22 is spaced in a transverse direction away from the support knuckle 16 so that there can be no interference.

A stirrup 30 is positioned so that it envelops the sprIng-end 24 and the support plate 26. The st:rrup 30 extends over the top surface of the support plate 26 and the bottom surface of the spring end 24. The stirrup is made of a flexible elastomeric material with continuous filamentary reinforcing aligned in the hoop direction. The elastomer utilised in the stirrup 30 can be a material such as rubber, polyurethane or other flexible material so long as the material is generally impervious to solvents that may be encountered in a vehicle environment. The filamentary reinforcing material can be R7M) a polyamide such as nylon, Kevlar Aor even glass fibres.

As viewed from above as in a plan view, the leaf spring 22 is relatively stiff thus causing undesirable rigidity to a compliant suspension linkage in the longitudinal sense. While the leaf spring 22 can capably provide vertical springing, it should not exert other stiffness effects on the overall wheel assembly 10. The flexible stirrup 30 provides adequate vertical rigidity and strength, yet almost zero initial stiffness in other directions. As displacement occurs between the support plate 26 and the spring end 24 along the longitudinal axis 12, the stiffness of the stirrup in the longitudinal plane rises progressively with increased displacement. Because of the flexible nature of the stirrup 30, a small displacement between the support plate 26 and the spring end 24 can be accommodated.

The stirrup 30 is arranged so that its vertical sides are essentially equal to one another.

Consequently, when there is relative movement between the support plate 26 and the spring end 24 the stirrup 30 assumes a configuration of a parallelogram such that the planar surfaces of the spring end 24 always remain parallel with respect to the longitudinal extent of the support plate 26 thereby avoiding the application of a torsional load on the leaf spring 22. The overall 11 flexibility of the stirrup 30 is such that it can act as a universal joint, permitting small steer angles from the support knuckle 16.

Figure 2, which is a broken away perspective view of the interconnection between a wheel lower control arm 32 and the leaf spring 22, shows yet another application of the flexible stirrup suspension concept. The control arm 32 is positioned directly above the leaf spring 22 and the stirrup 30 is positioned so that it circumscribes both the control arm 32 and the spring end 24. In order to prevent the stirrup 30 from drifting from its initial installation position, a top surface 34 of the control arm 32 is fabricated with a protrusion such as depicted by numeral 36. 'The protrusion 36 is positioned on both sides of the stirrup 30 thus providing resistance to drifting of the stirrup 30 in a transverse direction. In general use, the control arm 32 is pivotally attached to the support knuckle 16 of the overall wheel assembly 10.

Figure 3 is a sectioned end view of the stirrup 30 utilised in the present invention. The stirrup 30 lends itself to initial fabrication in a continuous tubular piece that can then be severed to the desired length. The optimum position for the reinforcing material is to orient it in the hoop direction of the stirrup 30. The severing of individual stirrups 30 from a tubular length of material would have minimal effect on the hoop oriented reinforcing material. As an alternate to the fabrication of continuous tubular stock, individual stirrups 30 can be moulded to the desired configuration, including rounded corners as depicted. In order to provide different degrees of adjustability, the stirrup 30 can be fab-1-cated in varying sizes sucl- as illustrated by the dotted lines 38.

12 Figure 4 is a part broken schematic side view of the lower control arm 32 with a stirrup 30 in an operative position. The control arm 32 is most generally fabricated from metal such as a steel forging, consequently it is possible to form the protrusions 36 as an integral part thereof. While in theory vehicles such as automobiles are symmetrical about the longitudinal axis, in practice there can be a variation in dimensions from one side of the automobile to the other side because of parts manufacturing and assembly tolerances. Consequently, it is frequently necessary to place shims at strategic locations during assembly. Figure 4 shows a shim 40 that has been inserted between the top surface 34 of the control arm 32 and the interior top surface 42 of the stirrup 30. The shim 40 has angled flanges 44 that are complementary to the protrusions 36 of the control arm 32. Since the angled flanges 44 of the shims 40 are less than 90' with respect to the body portion thereof, the shims 40 are stackable so that more than one shim 40 can be utilised at the same location. once the shims 40 have been installed, the sprung mass of the vehicle exerts a downward force on the leaf spring 22 locking the shims 40 in place.

Figure 5 is a sectional view of an embodiment of the present invention. The support plate 26 is depicted at the top of Figure 5 and the leaf spring 22 at the bottom thereof. A strap 46 is positioned and attached to a vertical edge 48 of the support plate 26. In a similar manner, the strap 46 is attached to a vertical edge 50 of the leaf spring 22. The strap 46 can be constructed in a tubular configuration then flattened during installation. The strap 46 need not be necessarily constructed from tubular stock since a unitary single thickness strap 46 would work equally well for purposes of the present 1 0 1 13 invention concept. To preserve the structural integrity of the strap 46, rigid mounting plates 52 are interposed between the end layers of the flattened strap 46. The straps 46 and the included mounting plates 52 are anchored to the support plate 26 and the leaf spring 22 by a plurality of bolts 54. The above described strap assembly is quite versatile in that installation and repair can be made without any disassembly of the overall wheel assembly 10. The twin strap assembly can be fine tuned by adjustment means to be described hereinbelow.

Figure 6 is a sectional view of another embodiment of the present invention. The support plate 26 and the leaf spring 22 are depicted in spaced apart relationship to one another. A sling 56 is attached to one of the vertical edges 48 of the support plate 26 with one or more of the bolts 54. The sling 56 loops around the bottom of the leaf spring 22 and is then fastened to the other vertical edge 48 of the support plate 26 with the bolts 54. In this manner, the use of bolts in the leaf spring 22 is avoided. This is of particular importance in those instances when the leaf spring 22 is made of composite non-metallic material. The top edges of the sling 56 utilises the mounting plates 52 as previously described.

The sling 56 can be adjusted as will be set forth in the discussion associated with Figure 7.

Figure 7 is a sectional view of a telescoped stirrup with adjustment means provided for each free standing leg of the stirrup arrangement. An outer stirrup 58 is assembled with a telescoping inner stirrup 60. The lengths of the parameters of the inner and outer stirrups 58 and 60 are tailored so that contact will be made between the stirrups E3 ai.td 60 over their entire common surfaces. The sub-assembly created by the inner and outer 14 stirrups 58 and 60 is placed in an installed position such as depicted with the single stirrup 30 of Figure 1.

In order to adjust the stirrup 58 and 60 combination for variances in the spacing between the leaf spring 22 and the support plate 26, an insert 62, made preferably of an elastomeric composition, is positioned between the inner and outer stirrups 58 and 60. The insert 62 is positioned at the midpoint of the vertical extent of the stirrups 58 and 60 that spans the distance between the support plate 26 and the leaf spring 22. The inserts 62 can be varied in thickness so as to compensate for nonparallelism that may exist between the support plate 26 and the leaf spring 22. The above method of adjusting the sling 56 shown in Figure 6 and the straps 46 shown in Figure 5 can also be adjusted by means of the inserts 62. The downward force of the leaf spring 22 will bias the vertical legs of the straps 46, the sling 56 and the telescoped stirrup 58 and 60 together, thus captivating the inserts. As an additional precaution against 20 inadvertent transverse movement of the inserts, an adhesive can be used or fasteners such as rivets (not shown) can be installed.

During the installation of the leaf spring 22 as shown in Figure 1, the stirrup 30 is slipped over each of the spring ends 24 and the leaf spring 22 is secured to the chassis of the vehicle. After the support knuckle 16 is attached, the spring end 24 can then be moved toward the support plate 26 by clamp or jack means. The stirrup is then moved into its proper position and the constricting force between the spring end 24 and the support plate 26 is then slowly released.

i j 1 The present invention, during its operation in conjunction with a vehicle, provides a new and novel wheel suspension. In particular, motor vehicles that are powered by a front mounted engine can employ independent rear wheel suspension systems. The stirrup 30, the straps 46, the sling 56, and the telescoping inner and outer stirrups 58 and 60 each provide for transverse movement of the leaf spring 22 without adversely affecting the suspension characteristics as the wheel rises and falls.

Also, as the rear wheel recesses, the stirrup 30 will also move without placing undue bending and torque moments on the leaf spring 22.

Although the invention set forth above is described in relation -to nonsteerable wheels of a vehicle, it is also applicable to steerable wheels. The invention is also applicable to unpowered vehicles, i.e. trailers or semi-trailers, as well as powered motor vehicles.

It should be understood that the invention is not limited to the foregoing embodiment, and that changes and modifications can be readily made by one skilled in the art without departing from the scope of the claims appended hereto. It is to be understood that when we refer to the chassis of a vehicle, we include an integral body-chassis structure such as is provided in most modern passenger automobiles.

f- 16

Claims

1. A vehicle suspension structure for controlling the movement of a wheel support assembly, of a vehicle having wheels and a chassis, said vehicle suspension structure comprising: at least one wheel support knuckle pivotally attached to a portion of said vehicle chassis; a wheel spindle on said at least one wheel support knuckle, said wheel spindle being disposed substantially horizontally and transversely with respect to said vehicle chassis, one of said wheels being mounted on said wheel spindle for carrying a proportionate amount of the mass of said vehicle; support means connected to and extending from said at least one wheel support knuckle to react a load applied in a substantially vertical direction; a leaf spring disposed to extend transversely of said vehicle adjacent said at least one wheel support knuckle; and resilient means interconnecting said support means and an end of said leaf spring whereby a portion of said vehicle sprung mass is communicated in a resilient manner to said one of said wheels.

2. A vehicle suspension structure for controlling the movement of a wheel support assembly of a vehicle having wheels and a chassis, said vehicle suspension structure comprising: at least one wheel support knuckle pivotally attached to a portion of said vehicle chassis; a wheel spindle on said at least one wheel support knuckle, said wheel spindle being disposed substantially horizontally and transversely with respect to said vehicle chassis, one of said wheels being mounted for rotation on Z 1 J_.

k 17 said wheel spindle so as to carry a proportionate amount of the mass of said vehicle; support means coupled to and extending in a substantially horizontal direction from said at least one wheel support knuckle to react a load applied in a substantially vertical direction; a leaf spring disposed to extend transversely of said vehicle adjacent to said at least one wheel support knuckle; and resilient means, having a plurality of load carrying members, interconnecting said support means and an end of said leaf spring whereby a portion of said vehicle sprung mass is communicated in a resilient manner to one of said wheels.

3. A vehicle suspension structure for controlling the movement of a wheel support assembly of a vehicle having wheels and a chassis, said vehicle suspension structure comprising:

at least one wheel support knuckle pivotally attached to a portion (of said vehicle chassis; a wheel spindle on said at least one wheel support knuckle, said wheel spindle being disposed substantially horizontally and transversely with respect to said-vehicle chassis, one of said wheels being mounted for rotation on said wheel spindle so as to carry a proportionate amount of the mass of said vehicle; support means connected to and extending in a substantially horizontal direction from said at least one wheel support knuckle transversely toward the centre of said vehicle to react a load applied in a substantially vertical direction; a leaf spring attached to said vehicle chassis and positioned to extend transversely of said vehicle adjacent said at least one wheel support knuckle; and i 18 resilient means, having a plurality of load carrying members, positioned in a substantially vertical attitude, said resilient means interconnecting said support means and an end of said leaf spring so that a portion of said vehicle sprung mass is communicated in a resilient manner to one of said wheels.

4. A vehicle suspension structure according to any one of the preceding claims wherein said support means is rigidly attached to said at least one wheel support 10 knuckle.

5. A vehicle suspension structure according to any one of the preceding claims wherein said support means comprises a support plate having a top surface of planar configuration and a cantilevered free end.

6. A vehicle suspension structure according to Claim 5 wherein said top surface is curvilinear in configuration.

7. A vehicle suspension structure according to Claim 5 or Claim 6 wherein said support plate further comprises an upstanding flange at the extremity of said support plate 20 cantilevered free end.

8. A vehicle suspension structure according to any of Claims 1 to 3 wherein said support means is pivotally attached to said at least one wheel support knuckle.

9. A vehicle suspension structure according to any one of the preceding claims wherein said support means further comprises a control arm, said control arm having a top surface of planar configuration.

If A 19

10. A vehicle suspension structure according to Claim 9 wherein said control arm further comprises spaced apart protrusions on said top surface.

A vehicle suspension structure according to Claim 5 or any of Claims 6 to 10 as appendant thereto wherein at least one shim is positioned between said resilient means and said top surface of said support means.

12. A vehicle suspension structure according to any one of the preceding claims wherein said resilient means comprises a continuous stirrup of single thickness.

13. A vehicle suspension structure according to Claim 12 wherein said continuous stirrup surrounds a top surface of said support means and a bottom surface of one end of said leaf spring end.

14. A vehicle suspension structure according to any one of the preceding claims wherein said resilient means comprises two continuous stirrups each folded together.

15. A vehicle suspension structure according to Claim 14 wherein said support means further comprises a first edge portion and a second edge portion opposite said first edge portion; and wherein said leaf spring further comprises a first edge portion and a second edge portion opposite said first edge portion; and further wherein said two continuous stirrups are each attached to one of said first and second edge portions of said support means and each attached to one of said first and second edge portions of said leaf spring, respectively.

16. A vehicle suspension structure according to any one of Claims 1 to 11 wherein said resilient means comprises I - R- one continuous stirrup folded together so as to form two ends having an intermediate portion therebetween.

17. A vehicle suspension structure according to Claim 16 wherein: said support means further comprises a first edge portion and a second edge portion opposite said first edge portion; one of said two ends is attached to one of said first and second edge portions of said support means; the other of said two ends is attached to the other of said first and second edge portions; and said intermediate portion of said continuous stirrup surrounds a bottom surface of said leaf spring.

18. A vehicle suspension structure according to any one is of Claims 1 to 11 wherein said resilient means comprises two continuous stirrups, one telescoped within the other.

19. A vehicle suspension structure according to Claim 18 wherein said two continuous stirrups surround a top surface of said support means and a bottom surface of said leaf spring.

20. A vehicle suspension structure according to Claim 19 further comprising height adjustment inserts positioned in at least one location in the interstices between said two continuous stirrups.

21. A vehicle suspension structure according to any one of Claims 12 to 20 wherein the or each said continuous stirrup is made of composite fibre reinforced elastomeric material.

1 21

22. A vehicle suspension substantially as hereinbefore described with reference to the accompanying drawings.

Published 1991 atMe Patent Oflice, State House. 66/71 High Holborn. London WCIR47P. Further copies Tn2y be obtained from Sales Branch. Unit 6. Nine Mile Point. Cwntlelinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques lid. St Mary Cray, Kent- - ---- - -.- - --.- - -. -. -- -U. - -Y tray, nent-