WO2015042662A1

WO2015042662A1 - Conversion of a two-wheel drive vehicle to a four-wheel drive vehicle

Info

Publication number: WO2015042662A1
Application number: PCT/AU2014/050247
Authority: WO
Inventors: John Ellis; Danny MILTON
Original assignee: Enduroco Pty Ltd
Priority date: 2013-09-24
Filing date: 2014-09-24
Publication date: 2015-04-02
Also published as: AU2014328481B2; AU2014328481A1

Abstract

ABSTRACT There is disclosed a kit of parts which can be installed to convert a two-wheel drive vehicle to a four-wheel drive vehicle, comprising: a live axle, including a differential housing and a differential within the housing; spring mounts; lateral and longitudinal axle constraints; and a sub-frame mountable to a chassis of the vehicle, the sub-frame having: oppositely disposed strut supports, each being for locating a respective one of the spring mounts between the sub- frame and the live axle; and a body adapted to extend laterally across the chassis to interconnect the strut supports when the sub-frame is mounted to the chassis, the body including a mounting structure, formed in a portion thereof, for mounting an engine for the vehicle, wherein a portion of the body and a said strut support are configured such that a space is defined adjacent the mounting structure for location of the differential housing relative to the engine when the sub-frame is mounted to the chassis.

Description

, I -

Conversion of a two-wheel drive vehicle to a four-wheel drive vehicle

The present invention relates to conversion of a two-wheel drive (2 WD) vehicle to a four- wheel drive (4WD) vehicle.

Conversion of vehicles, such as cars or trucks, from 2WD to 4WD is known. Often, such conversion is time-consumin and labor-intensive, and thus generally carried out on a "one-off" basis. Generally, conversion of a 2WD vehicle to a 4WD vehicle requires substantial effort and reconfiguration, of the vehicle engineering. For example, a conventional 4WD vehicle, converted from a rear- wheel drive vehicle, requires a f ont differential, for driving the front wheels, connectable to a transfer case whic distributes power from the engine to the front wheels and rear wheels so they can operate independently. Typically, a shortage of room around the engine bay necessitates positioning the front differential close to the ground with the result that changes in terrain when the vehicle is driven can cause the differential to contact the ground, particularly given an increased suspension travel in the vehicle which may follow from the conversion. Consequent damage to the differential can be significant. Although the vehicle ride height or ground clearance can be increased to compensate, an increase in ride height/ground clearance can result i higher load-bearing stresses and usually requires replacement of the vehicle suspension, system with a specialised suspension kit.

In addition to requiring a front differential for converting a 2WD vehicle to a 4WD vehicle, and increasing the vehicle ride height/ground clearance to space the front differential sufficiently from the ground, prior art conversions typically require substantial reinforcing of the chassis and replacement parts, that are generally welded and bolted to the chassis, to manage and support increased load stresses placed o axles and suspension systems in 4WD applications. Further, while factory sub-assemblies for 2WD vehicles generally include fixtures for mounting the vehicle engine, there is generally no means of accommodating or supporting a differential, let alone upgrading the suspension and _ ~ steering to accommodate: increases suspension travel. Therefore, in order to convert a 2WD rear-wheel drive vehicle to a 4WD vehicle, substantial rework and re-engineering; is required. Prior art 2WD - 4WD conversions have therefore been largely impractical for commercial implementation, the complexities and mechanics of such conversions being such that they have often been the realm of backyard enthusiasts. Particular drawbacks of many prior art conversions have been a lack of compliance with vehicle safety standard and resultant adverse effects on vehicle insurance policies.

The content of the specification of Australian provisional application no. 2013903681, entitled Assembly far 4WD conversion of a 2 WD vehicle, is hereby incorporated herein by reference, According to a First aspect of the present invention, there is provided a kit of parts which can be installed to convert a two-wheel drive vehicle to a four-wheel drive vehicle, comprising:

a live axle, including a differential housing and a differential within the housing; spring mounts;

lateral and longitudinal axle constraints; and

a sab-frame .inountable to a chassis of the vehicle, the sub-frame having:

oppositely disposed strut supports, each being for locating a respective one of the spring mounts between the sub-frame and the live axle; and

a body adapted to extend laterall across the chassis to interconnect the strut supports when the sub-frame is mounted to the chassis, the body including a mounting structure, formed in a portion thereof, for mounting an engine for the vehicle,

wherein a portion of the body and a said strut support are configured such that a space is defined adjacent the mounting structure for location of the differential housing relative to the engine when the sub-frame is mounted to. the chassis. According to a second aspect of the present invention, there is provided a kit of parts which can he installed to convert a two-wheel drive vehicle to a four-wheel drive vehicle, comprising:

lateral and longitudinal axle constraints; and

a sub-frame mountable to a chassis of the vehicle, the sub-frame having:

a body adapted to extend laterally across the chassis to interconnect the strut supports when the sub-frame is mounted to the chassis, the body including a mounting structure, formed in a portion thereof, for mounting an engine for the vehicle,

a space, adjacent the mounting structure, being defined by a said strut support and portion of the body, for location of the differential housing relative to the engine when the sub-frame is mounted to the chassis.

In a preferred embodiment of the second aspect of the invention, the said strut support with which said portion of the body define a space, extends upwardl from the body, thereby allowing the space to be formed, and it is in this sense that it, together with the body, "defines" the space.

In one preferred embodiment of the first or second aspect of the invention, the strut supports are mountable to the chassis separatel from the body, whereby the bod interconnects the strut supports via the chassis, i.e. indirectly. In another preferred embodiment of the first or second aspect of the invention, the body and stint supports are directly interconnected or directly interconnectable.

The sub-frame may have a construction whic comprises a 5-piece reinforced tubula assembly havin a body portion and strut supports that can be installed with no welding to the original chassis. According to a third aspect of the present invention, there is provided a kit of parts which can be installed to convert a two-wheel drive vehicle to a four-wheel drive vehicle, comprising:

a live axle, having a differential housing and an integral differential within the housing;

coil suspension mecbanisnis;

lateral and longitudinal axle constraints; and

a sub-frame moimtable to a chassis of the vehicle, the sub-frame having:

a shaped central bod adapted to extend transverse to a longitudinal axis of the vehicle and adjacent to the live axle, the body including a rece sed portion and engine mounts adapted for receivin an engine for the vehicle; and

opposed pairs of mounting arms extending from opposite ends of the central body, each pair of mounting arms being provided with a mounting portion configured to receive one end of a respective said coil suspension mechanism, wherein a said pair of arms and at least a portion of the bod adjacent the recessed portion are configured such that there is defined a space for accommodating the differential.

According t a fourth aspect of the present in vention, there is provided a kit of parts which can be installed to convert a two-wheel drive vehicle to a four-wheel drive vehicle, comprising:

a live axle, having a differential housing and a integral diiferential within the housing;

coil suspension mechanism^'s;

lateral and longitudinal axle constraints; and

a sub-frame mountable to a chassis of the vehicle, the sub-frame having:

a shaped central bod adapted t extend transverse to a longitudinal axis of the vehicle and adjacent to the live axle, the body including a recessed portion and engine mounts adapted for recei ing an engine for the vehicle; and

opposed pairs of mounting arms extending from opposite ends of the central hody, each pair of mounting arms being provided with a mounting portion configured to receive one end of a respective said co.il suspension mechanism, wherein a said pair of arms and at least a portion of the body adjacent the recessed portion define a space for accommodating the differential.

In a preferred embodiment of the fourth aspect of the invention, the said pair of arms, with which at least a portion of the body adjacent the recessed portion defines a space, extends upwardly from the body, tliereby allowing the space to be fomied, and it is in this sense that it, together with the body, "defines" the space.

In a preferred embodiment of the invention, the mountin structure or recessed portion and space allow relative location of the differential housing and the engine whereby the differential housing is suspended offset from the engine at a height from the ground which is such that it overlaps the engine.

In preferred embodiment of the invention, the mounting structure or recessed portion and space allow relative location of the differential housing and the engine whereby the differential housing is suspended offset from the engine at a height from the ground which is sufficient that it at least overlaps the engine.

In a preferred embodiment of the invention, the mounting structure or recessed portion and space allow relative location of the differential housing and the engine such that the differential housing is suspended offset from the engine at a height from the ground at least, overlapping the engine.

In a. preferred embodiment of the invention:

each strut support comprises a pair of arms and a sprin mounting portion, interconnecting the arms, for locating a respective one of the spring mounts between the sub- frame and the live axle; or

the mounting portion with which each pair of arms is provided is for receiving said one end of the respective coil suspension mechanism. Preferably, each mounting portion includes an opening for receiving a respective said one end. In a preferred embodiment of the invention:

each strut support comprises a pair of aims and a spring mounting portion, interconnectin the arms, the spring mountin portio including a opening for receiving one end of a respective one of the spring mounts; or

the mounting portion with which each pair of arms is provided includes mounting openin for receiving said one end of d e respective coil suspension mechanism.

In the preferred embodiments of the invention, the iateral and longitudinal axle constraints are for constraining the axle in a lateral direction and distortion of the axle in a longitudinal direction, respectively.

In a preferred embodiment of the invention, each pair of arms is provided with mounts, distal a respective said mounting portion, adapted for mounting the sub- frame to the chassis by fastening means. I a preferred embodiment of the invention, the mounts with which each pair of arms is provided are handed mounts or hand portions.

In a preferred embodiment of the invention, eac mounting portion interconnects a respective said -pair .of .arms such that there is formed an inverted V-shaped configuration.

In a preferred embodiment of the invention, each mounting portion comprises a rin structure forming a mounting opening adapted to receive one end of the respective spring mount or coil suspension mechanism. In a preferred embodiment of the invention, the strut supports o pairs of amis are provided with opposite facing flange mounts attached to the mounting portions to form chassis mount locations.

In a preferred embodiment of the invention, the strut supports include, or pairs of arms are provided with,, opposite facing flange mounts aitached to the ring structures and forming chassis mount locations.

In a preferred embodiment of the invention, the mounting structure or recessed portion is a cradle structure for receiving and supporting the engine. In a preferred embodiment of the invention, the mounting structure or recessed portion includes a cradle structure for locating and supportin the engine relative to the differential housing.

In a preferred embodiment of the invention, the recessed portion or cradle structure. includes oppositely disposed engine mounts for mounting the engine within the recessed portion or cradle structure.

In a preferred embodiment of the invention, the longitudinal axle constraint comprises a pair of radius anus.

In a preferred embodiment of the invention, the kit further comprises a pair of radiu arm mounts and each radius arm is adjustably mountable at one end to a portion of the chassis and interconnected or interconnectab!e at the opposite end with the live axle by a respective one of the radius arm mounts.

In a preferred embodiment of the invention, the radius arm mounts allow a degree of freedom of twisting and height adjustment of the live axle depending on terrain over which the vehicle travels. In a preferred embodiment of the invention, each radius arm mount incorporates two pivot mounts. In a preferred embodiment of the invention, the lateral axle constraint comprises a rod member adapted for mounting between the live axle and the chassis, In a preferred embodiment of the invention, the rod member can articulate with suspension movement.

In a preferred embodiment of th invention, the rod member includes at least two components joined by a bushing member so that the rod raember can articulate with suspension movement.

In a preferred embodiment of the invention, each spring mount or eoil suspension mechanism comprises a coil spring and a damper. The damper can be received within the coil or the coil and damper can be separated. In an alternative embodiment of the present invention, the spring mounts comprise leaf springs.

In a preferred embodiment of the invention, wherein the differential housing is arranged or mounted off-centre on the live axle, I a preferred embodiment of the invention, the ki further comprises a steerin means.

In a preferred embodiment of the invention, at least a part of the steering means is mounted to a cover portion of the housing. In a preferred embodiment of the invention, the housing includes mounting portio for securing at least a pan, of the steering means.

In a preferred embodiment, of the invention, .the kit includes a pair of removable ABS trigger wheels and a pair of hubs, each trigger wheel and a respective oae of the ubs being configured such that, when the kit is installed, they form part of a modified hub and brake assembly, for a respective wheel, of the vehicle, which iadudes original brake components for that wheel. Each trigger wheel, may includes -inclined teeth whereby it can mate with a respective said hub.

In a preferred embodiment of the invention, the kit further includes a stone deflector element mountable to a front end portion of the chassis.

Preferred embodiments of the present invention provide an effective means for convertin a 2WD vehicle to a 4WD vehicle, hi particular, the sub- frame is easily fitted without a requirement of substantial labour or parts, or extensive welding, allowing conversion in commercial quantities.

The rod member can further include at least two components joined b a bushing member so that the rod can articulate with suspension movement. According to a further aspect of the present invention, there is provided an assembly for converting a 2 WD vehicle to a 4WD vehicle including;

a live axle and integral differential within a differential housing;

a coil suspension;

a lateral and longitudinal axle constraints for supporting distortion of the axle in lateral and longitudinal directions of the vehicle chassis, wherein the longitudinal constraint: includes opposite radius arms mounted between the chassi and the live axle; and

a sub-frame structure mountable to the vehicle chassis, the sub-frame structure including;

a central body adapted to extend substantially transverse to the longitudinal axis of the vehicle and adjacent to the live axle;

a pair of opposed strut supports having mounting arms extending from opposite ends of the central body, the mounting arms having a mounting portion including a mounting opening for receiving one end of the coil suspension, and the arms including handed mounts adapted for mountin to the vehicle chassis, and whereby in an. assembled condition the coil suspension is located between the live axle and the mounting portions of the sub-frame; and

wherein the central body of the sub-frame includes a recessed portion and engine mounts therein adapted for receiving an engine, and wherein the arms of at least one strut support and at least a portion of the central body adjacent the recessed portion, define a space for accommodating the differential housing.

In one embodiment, the radius arms are interconnected to the chassis by a radius arm chassis pivot mount at one end, and interconnected at the opposite end to the axle by a radius arm axle mount. The chassis pivot mount and the radius arm axle mount provide a degree of movement of the axle.

Preferred embodiments of the invention provide a conversion kit which is convenient to install and improves the overall performance ride and ride height of a vehicle. Preferred embodiments of the invention provide a practical means of converting a 2WD vehicle to a 4WD vehicle on a commercial scale, which not only meets regulatory safet requirements but is also efficient.

The invention will now be described, by wa of non- limiting example only, with reference to the accompanying drawings, in which:

Figure 1 is an upper front perspective view showing pieces of a sub-frame of a 2WD-4WD conversion kit according to a first preferred embodiment of the present invention in a disassembled condition;

Figure 2 is a front side perspective view showing details of the kit of the first embodiment installed;

Figure 3 is a bottom view showing details of the installed kit of the first embodiment;

Figure 4 is an upper front side perspective view showing details of the installed kit of the first embodiment;

Figure 5 is a further upper front side perspective view showing details of the installed kit of the first embodiment;

Figure 6 is front side perspective view showing a vehicle fitted with the kit of the first embodiment;

Figure 7 is a lower rear side perspective view showing details of the installed kit of the first embodiment;

Figure 8 is a lower front sid perspective view showing details of the installed kit. of the first embodiment from which are omitted details of a steering arrangement of the kit for the purposes of clarity;

Figure 9 is a front perspective view showin details of the installed kit of the first embodiment, from which are likewise omitted details of the steering arrangement for the purposes of clarity; Figure .10 is a perspective view of the kit of the first embodiment including an exploded view of one of two front wheel hub and brake assemblies of the vehicle as converted by installation of the kit according to the first embodiment;

Figure 1 1 is an exploded perspective view showing details of the wheel hub and brake assembly shown in Figure 10;

Figure 12 is bottom view showing details of a kit according to a second preferred embodiment of the in vention installed in a vehicle; Figure 13 is an upper front side perspective view showing details of a kit. according to a third preferred embodiment of the present invention installed in a vehicle; Figure 1 is a rear side perspective view showing details of the installed kit of (he third embodiment; Figure 1.5 is an upper front side perspective view showing details of the- installed kit of the third embodiment;

Figure 16 is a detailed perspective vie showing details of the installed kit of the third embodiment; and

Figures 17A and 17B are schematic views of the vehicle drive trail, pre-conversion and post-conversion respectively.

Referring to the drawings, there are shown details of a kit of parts which can be instaLled to convert a 2WD vehicle, and more particularly a rear-wheel drive vehicle, to a 4WD vehicle. Referring in. particular to Figure 6, which shows a kit according to a. first preferred embodiment of the invention installed in a light vehicle (a Toyota Commuter), and also to Figure 1, the kit comprises a sub-frame 1, which mounts to a chassis 2 of the vehicle, a live axle 3, which includes an integral differential housing 4 and an integral differential within the housing 4, spring mounts 5, each extending between the sub-frame 1 and live axle 3 at a respective side of the vehicle. The sub-frame 1 is configured to support the vehicle engine 50 and to accommodate the differential housing 4, as will be described in further detail later. The component members of the sub-frame 1 comprise an intermediate body 7, securable at opposite ends thereof to the chassi 2, and strut supports 40, each of which comprises a strut member 40a securable at a lower end thereof to the chassis 2 adjacent a respective end of the body 7 and bracket 16 defining a mountin support which can be fixed to a upper end of the strut member 40a arid the chassis 2, The strut members 40a and body 7 comprise reinforced tubular assemblies/structures. Referring to Figures 3, 4 and 7, each end of the body 7 is configured with a pair of spaced apart mounting portions 7a, each mounting portion being configured with a through-hole. The mounting portions 7a of each pair are receivable against the underside of a respective one of the chassis rails 2a of the chassis 2 and securable to it via bolts received through the holes and into mounting holes in the rail 2a (which may be pre-existing).

The body 7 is configured with a cradle 14 arranged to receive and support the engine 50, and includes opposed engine mounts 35, each comprising a mounting face, at or adjacent a respective laterally outer end of the cradle 14, with holes to receive fastening elements, to which opposite sides of the engine are securable whereby the engine is supported by the body 7 and a lower section thereof is accommodated in the cradle 14.

The body 7 additionally comprises opposed arm portions 7b, each of which extends substantially laterally from a respective end of the cradle mounting structure, at laterally outer ends of which a respective pair of mounting portions 7a is arranged. Advantageously, owing to the configuration of the body 7, a space 17 is defined adjacent the cradle mounting structure to either side thereof. Advantageously, when the body 7 is mounted to the chassis 2, one of the spaces 17 accommodates the differential housing 4, permitting it (and the rest of the live axle 3) to be located in the appropriate position relative to the motor 50.

Each strut member 40a comprises an upwardly convergent pah of arms 6, forming: a substantially inverted V-shaped structure which, when the kit i installed, extend upwardly from the bod 7(as can be seen in Figures 2, 5, 6, 8 and 10), upper ends of whic arms are interconnected by a mounting portion 9, which comprises a. tubular U-shaped member having a base section 9b and parallel leg sections 9c projecting laterally inwardly from opposite ends of the base section 9b, and a plate portion or ring structure 9d which is secured to the base portion 9b and extends laterall inwardly therefrom and is configured with a central opening 9e therethrough. Each strut member 40a further comprises a plate or flange portion 8 which is attached to laterally inner ends of the legs 9c, and to which is attached a laterally inner end of the ring structure 9d. Each strut member 40a further comprises respective mounts 1 1 , provided at laterally inwardl bent lower ends of the arm 6, each mount 1 1 being configured in the form of a flange or plate portion configured with mounting holes therethrough so as to be fastenable, by fastening elements, against a laterally outwardly facing upright surface of the chassis 2, as shown in Figures 2, 5, 6, 8 and 10. The strut members 40a are not symmetrical, the mounts 11 on one of them being handed oppositely to those on the other, whereb each strut member is dedicated to a respective side of the cliassis and the mounts 11 thereof match up with the fixing points on the chassis at that side.

The sections 9b, 9c and portion/structure 9d define mounting platforms.

Each mounting support bracket 16 is formed at an upper end thereof with an upright flange portion 16a arranged so as to abut the flange 8 of the respective strut member 40a and configured with holes 16b which are arranged to align with corresponding holes (not shown) through the flange 8 whereby fasteners can be secured through the aligning holes such that the flange portion 16a is fixed, to the flange 8. The brackets 16 connect at their lower ends to the chassis 2. Referring to Figures 3 to 5, the kit further comprises a steering arrangement 20, which comprises a steering box 22 and a link, arrangement comprising an arm 24, fixed to and extending radially outwardly from an output shaft of the steering box 22, a drag link 25, pivotally connected at one end to a distal end of the arm 24, an arm 26a fixed to and extending radially from one of two opposed end axle pivotally mounted assemblies 60 of the live axle, to which arm the drag link 25 is connected at. its other end, and arm 26b fixed to and extending radiall from the other end axle assembly 60, and a tie rod 27 pivotally connected, at opposite ends thereof, to distal ends of the arms 26a, 26b. Rotary output from the steering box 22 imparts a torque through arm 24, and via drag link 25 and tie rod 27, thence to the axle assemblies 60 to steer the vehicle, The end axle assemblies 60 will be described in further detail later. The steering box 22 is moimtab!e to one of the chassis rails 2a, as can best be seen in Figures 2 and 4 to 6. An input to the steering box 22 is connectable to the steering shaft of the vehicle via a double universal coupling, which transmits torque from the steering shaft to the steering box 22.

The spring mounts 5 comprise coil suspensions, each of which comprises a sprung coil or suspension coil 30 and damper 1, comprising a damper rod, configured to extend between the mounting platform of a respective strut support 40 and the live axle 3. The central opening e receives an upper end of the sprung coil 30, a lower end o that coil being received by a respective one of coil engagement portions 33 with which opposite end section of the live axle 3 are configured.

An upper end of the damper 31 is likewise received by an opening formed through a respective mounting platform whereby to be secured to that platform. A lower end of each damper 31 is secured to a respective one of opposed damper engagement portions 35 with which the live axle 3 is configured, in the presen embodiment, the sprung coil 30 and damper 31 of each spring mount 5 are separate and spaced apart* possibly allowing for greater displacement of the respective front wheel of the vehicle (relative to the chassis 2). Each spring mount 5 thus extends between the sub-frame 1 and live axle 3.

Referring in particular to Figures 8 and 9, the kit additionally comprises a lateral axte constraint, for constraining the live axle 3 laterally, the lateral constraint comprising a panhard rod 19, a mounting bracket 19a via which one end of the panhard rod 19 pivotally connects to one of the chassis rails 2a, and a second bracket, secured to the differential housing 4, via which a second end of the pan hard rod 19 pivotally connects to the live axle 3, The connection between the ends of the panhard rod 19 and first and second brackets 19a and 19b incorporate rubber bushes designed to allow rotational motion about central axle 3 thereof as well as angular misalignment.. The kit additionally includes longitudinal constraints, which comprise laterally opposed radius arms 18, each of which is pivotally connectable at a rear end to a respective one of the chassis rails 2a via a pivot mount 18a and is pivotally connectable at a front end thereof to the live axial 3 via a radius arni mount 1.8b incorporating tw pivot mounts, the mounts 18 a and 18b also forming part of the kit. The front and rear attachments of each radius arm IS allow a degree of freedom of twisting and height adjustment of the live axle dependent on the terrain over whic the vehicle travels. The connections at each of the radius ami mounts 18a, 18b likewise incorporate rubber bushes, allowing rotational motion about their axes as well as angular misalignment, providing for easy implementation (owing in particular to a low part count) and substantially minimising loads on the chassi 2.

Referring now to Figures 10 and 1 1. the kit further includes a pair of removable ABS trigge wheels 90 and a pair of hubs 91, each trigger wheel 90 and a respecti ve one of the hubs 91, when the kit Is^' installed, forming part of a modifie huh and brake assembly, for a respective front, wheel of the vehicle, which includes the original brake components for that wheel, namely disc brake rotor 94, brake calliper 96, ABS sensor 9? and a brake calliper mount 98, which is configured to mount not only the callipe 96 but also th sensor 97. The trigger wheel 90 includes inclined teeth 9 (which may be necessitated by constraints imposed by surrounding components) whereby the trigger wheel 90 is fitted to the hub 91 and fitting or removal of the trigger wheel 90 for assembly/maintenance of the rotor 94 is permits/facilitated without any need to disassemble the wheel hub and brake rotor components. Advantageously, removal and maintenance of the brake rotors can be effected easily with the ABS trigger wheel in place, and that trigger wheel is removable in such a way that it c n be replaced, in the same location, without loss of any of the ABS settings,

Conversion of a 2WD vehicle to a 4WD vehicle involving installation of the kit according to the first preferred embodiment of the invention, will now be described.

Firstly, the engine 50 is disconnected from: the original sub-frame in silu then, while slung from overhead, disconnected from that sub-frame and connected to the new sub-frame in the manner described previously. With the engine 50 thus supported, and adequatel clear of the engine bay, the original front sub-frame and original suspension, which may comprise torsion bar or double-wishbone suspension, are decoupled from the chassis 2 and removed.

Next, referring to Figures 3 and 7 in particular, the body 7 is secured to the undersides of the chassis rails 2a via bolts received through portions 7a and corresponding holes formed in the rails 2a. and the engine 50 is secured to the body 7 via bolts received throug the holes in the flange portions 15, which fix the engine 50 to those portions 15, and is urislung.

Next, portions, or the entireties, of the original shock absorber towers or mounts (not shown), e.g. wishbone mounts, are cut out. A pre-assembly comprising the strut supports 40, spring mounts 5, live axle 3, radius arms 18, pivot mount 19 and panhard rod 19 is then installed. Referring to Figures 2, 5, 6, 7 and 10, the flanges 11 at the lower ends of the anus 6 of each strut member 40a are bolted against laterally outwardly facing side faces of the chassis 2, and the support bracket 16 are secured to the flanges 8 of the respective strut members 40a and to upwardly facing surfaces of the chassis 2, as previously described, whereby the live axle 3 is supported from the chassis 2. With the sub-frame 1 thus duly assembled and installed, the differential housing 4 is accommodated by one of the spaces 17 defined by the fitted body 7, as can best be seen in Figure 9. Referring additionally to Figure 8, the rear- ends of the radius a ms 18 are connected to the mounts 18a on the chassis rails 2a.

Subsequently, referring to Figures 3 to 7 and 10, the steering arrangement. 20 is installed. The steering box 22 is mounted to one of the chassis rails 2a and interconnected with the steering shaft via the link arrangement. The drag link 25 is connected between the steering box output, arm 24 and the arm 26a at the other side of the chassis, and the rod 27 is connected at one end to the arm 26a and at the end to the other ami 26b,

Anti-roll bar linkages 71 are provided, each of which is positioned adjacent a respective lateral end of the live axle 3, to which linkages respective ends of an anti-roll bar 72 (of the vehicle suspension system) connect, the anti-roil bar 72 being mounted adjacent forward end of the chassis 2 via anti-roll bar mounts 72a which are mounted to the front cross- member 2b of the chassis. The linkages 71, anti-roll bar 72 and mounts 72a may be original components of the vehicle or instead may be part of the kit.

The wheels and modified hub and brake assemblies, described previously with reference to Figures 10 and 1 1. are fitted to the respective end axle assemblies 60.

A kit according to a. second preferred embodiment of the invention will now be described with reference to Figure 12. This kit is substantially identical to that of the first embodiment, and is installed in substantially the same manner, except with respect t the panhard rod 19 and steering arrangement/assembly. In the second embodiment, the panhard rod 1 is connected, via mounting bracket 19a, to a chassis rail 2a whic is opposite to that to which the panhard rod connects (via the corresponding bracket) in the first embodiment, and is connected, vi mounting bracket 19b, to a part of the live axle 3 which is remote from the differential housing 4 (instead of being connected to the housing 4, via the corresponding bracket, as it is in the first embodiment). Also, the kit of the second embodiment does not include a steering arrangement/assembly comprising the steering box and linkage/tie rod arrangement; instead, the arms 26 are configured for mountin of rack 80, of a rack-and-pinion steering arrangement, which may form part of the original vehicle steering system or instead form a part of the kit. The kit includes a bracket 80a to mount the rack SO t the differential housing cover 4, whereby , somewhat unconventionally, owing to the rack's being so secured, there is reduced bump steer and sensitivity to pan hard rod orientation, as well as improved steering "feel" experienced by the driver. The kit of the second embodiment includes a telescopic intermediate shaft 81 which actuates the steering rack and is provided at opposite ends thereo with universal joints 81a, 81b. The telescopic shaft can comprise a coarse spline nib and bar or a ball spline arrangement, in which spherical roller bearings between the spline bar and housin allow relative axial movement betwee the spline bar and housing while torque i transmitted therebetween, Shown in Figures 13 to 1 is an installed kit accordin to a third preferred embodiment of the present invention. The kit is substantially identical to that of the second embodiment (so that most of what is shown in Figures 13 to 16 is likewise detail of the second effibodiment), and is installed in substantially the same manner, with the exception that, in each spring mount 5, the coil spring 30 and damper 31 are coaxial> the latter being accommodated -within, the former. The coil and damper engagemen portions 33, 35 thus may, in this embodiment, be integrated. The omission of details of the mounts .1.6 from Figures 13 to 16 is purely for clarity; those mounts 1.6 form part of the installed kit of the third embodiment.

The kit of each embodiment additionall includes purpose-built leaf springs, and the method of installing it includes replacing the rear suspension of the vehicle with the leaf springs, with the result that not only the spacing between the engine and the ground but also the ride height of the vehicle is increased by about 14cm, the additional ground clearance reducing the likelihood of damage to the underside of the vehicle body due to changing terrain,

Shown in Figures .17 A and 1.7B are schematic views of a drive train in the vehicle pre-conversion and post-conversion, respectively. Before the conversion, a drive shaft .100 transfers drive from the gearbox 110 to the rear differential 120 of the vehicle. The kit of each of the embodiments includes a transfe case 130 and a rear drive shaft 140, which replace the drive shaft 100, the transfer ease 130 being coupled to the output of the gearbox, and the drive shaft 140 connecting a rearwardly extending output shaft 134 of the transfer case 130 to the rear differential 120, The kit further includes a forward drive shaft 150 connecting a forwardly extending output shaft 136 of the transfer case 130 to the front differential 1 0 of the kit.

The kits and methods embodying the invention allow easy and effective conversion of a 2WD vehicle to a 4WD vehicle. In particular, the sub-frame is easily fitted to the chassis, reducing labour costs and conversion time substantially. While the present invention has been described with reference to a few specific embodiments, the description is illustrative of the invention and is not to be construed as limiting the invention. Various modifications may occur to those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.

A reference to any prior art in this specification is not, and should not be taken as, an acknowledgement or any form of suggestion that, the referenced prior ait forms part of the common general knowledge in Australia.

Throughout this specification, the words "comprise", "comprised", "comprising" and "comprises" are to be taken to specify the presence of stated features, integers, steps of components, but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof .

Claims

1. A kit of parts which can be instal led to convert a two- wheel dri ve vehicle to a four- wheel drive vehicle, comprising;

lateral and longitudinal axle constraints; and

a sub-frame mountable to a chassis of the vehicle, the sub-frame having:

wherei a portion of the body and a said strut support are configured such that a space is defined adjacent the mounting structure for location of the differentia! housin relative to the engine when the sub-frame is mounted to the chassis.

2, A kit of parts which can be installed to convert a two-wheel drive vehicle to a fotir- wheel drive vehicle, comprising:

lateral and longitudinal axle constraints; and

a sub-frame mountable to a chassis of the vehicle, the sub-frame having:

a body adapted to extend laterally across the chassis to interconnect the strut supports when the sub-frarae is mounted to the chassis, the body including a mounting structure, formed in a portion thereof, for mounting an engine for the vehicle,

a space, adjacen the mounting structure_* being defined by a said strut support and a portion of the body, for .location of the differential housing relative to the engine when the sub-frame is mounted to the chassis.

3. A kit according to claim 1 or 2, wherein the mounting structure and space allow relalive location of the differential housing and the engine whereby the differential housing is suspended offset from tile engine at a height from the ground which is such that it overlaps the engine,

4. A ki according to claim I or 2, wherein the mounting structure and space allow relative location of the differential hou ing and the engine whereby the differential housing is suspended offset from the engine at a height from the ground which is sufficient that it at leas overlaps the engine,

5. A kit according to claim 1 or 2, wherein the mounting structure and space allow relative location of the differential housing and the engine such that the differential housing is suspended offset from the engine at a. height from the ground at least overlapping the engine.

6. A kit according to any one of the preceding claims, wherein each strut support comprises a pair of arms and a spring mounting portion, interconnecting the arms, for locating a respective one of the spring mounts between the sub-frame and the live axle.

7. A kit according to claim 6, wherein each spring mounting portion includes an openin for receiving one end of the respective spring mount.

8. A kit according to any one of claims 1 to 5, wherein each strut support comprise a pair of arms and a spring mounting portion, intexconnecting the amis, the spring mounting portion including an opening for receiving one end of a respective one of the spring mounts,

9. A kit according to any one of claims 6 to 8, wherein, in each strut support, the pair of amis is provided with mounts, distal the spring mounting portion, adapted for mounting the sub -frame to the chassis by fa tening mean .

10. A kit according to claim 9, wherein the mounts with which each pair of arms is provided are handed mounts,

11. A kit according to any one of claims 6 to 9, wherein, in each strut support, the spring mounting portion interconnects the pair of arms such that there is formed an inverted V-shaped configuration.

12. A kit according to claim 11, wherein the spring mounting portion comprises a ring structure forming a mountin opening adapted t receive one end of the respective spring mount.

13. A kit according to claim 11 or 12, wherein the stint supports are provided with opposite facing flange mounts attachable to the spring mounting portions to form chassi mount locations .

14. A kit according to claim 13, wherein the strut supports include opposite facin flange mounts^' attachable to the ring structures and forming chassis mount locations,

15. A kit according to any one of the preceding claims, wherein the mounting structure is a cradle structure for receiving and supporting the engine.

16. A kit according to any one of claims 1 to 14, wherein the mounting structure includes a cradle structure for locating and supporting the engine relative to the differential housing.

17. A kit. according to claim 15 or 16, wherei the cradle stnicture includes a pair of oppositely disposed engine mounts for mounting the engine within the cradle structure.

18. A kit according to an one of the preceding claims, wherein the longitudinal axle constraint comprises a pair of radius arms.

19. A kit according to claim 18, further comprising pair of radius arm mounts and wherein each radius arm is adj stably mouniable at one end t a portion of the chassis and interconnected, or interconnectable at the opposite end with the live axle by a respective one of the radius arm. mounts.

20. A ki according to claim 18, wherein the radius arm mounts allow a degree of freedom of twisting and height, adjustment of the live axle depending on terrain over which the vehicle travels.

21. A kit according to claim 20, wherein each radius arm mount- incorporates two pivot mounts.

22. A kit according to any one of the preceding claims, wherein the lateral axle constraint comprises a rod member adapted for mounting between the live axle and the chassis.

23. A ^'kit according to claim 22, wherein the rod member can articulate with suspension movement.

24. A kit according to claim 22, wherein the rod member includes at least tw components joined b a bushing member so that the rod member can articulate with suspension movement

25. A kit according to any one of the preceding claims, wherein each spring mount comprises a coil spring and a damper.

26. A kit according to any one of the preceding claims, wherein the differential housing is arranged or mounted off-centre on the live axle.

27. A kit accordin to any one of the preceding claims, further comprising a steering means.

28. A kit according to claim 27, wherein at least a part of the steering means is mounted to cover portion of the housing.

29. A kit according to claim 28, wherein the housing includes a mounting portion for securing at least a part of the steering means.

30. A kit according to any one of the preceding claims, 'including a pair of removable AB.S trigger wheels and a pair of hah% each trigger wheel and a respective one of the hubs being configured such that when the kit i installed, they form part of a modified hub and brake assembly, for a respective wheel of the 'vehicle, which includes original brake components; for that heel .

3L A kit according to claim 30, -wherein each trigger wheel, tnclndes inclined teeth whereby it can mate wit a respective said hub.

32. A kit according to any one of the preceding claims, being one for conversion of a rear-wheel drive vehicle to a four-wheel drive vehicle.

33. A kit according to any one of the preceding claims, further including a stone deflector element mountable to a front end portion of the chassis.

34. A kit of parts which can he assembled to convert a two- wheel drive vehicle to a four-wheel drive vehicle, comprising:

a live axle, having a differential housing and an integral differential within the housing:

coil suspension mechanisms;

lateral and longitudinal axle constraints; and a sub-frame mountabl.e to a chassis of the vehicle, the sub-frame having:

a shaped central body adapted to extend transverse to a longitudinal axis of the vehicle and adjacent to the live axle, the body including a recessed portion and engine mounts adapted for receiving an engine for the vehicle; and

opposed pairs of mounting arms extending from opposite- ends of the central body, each pair of mounting amis being provided with a mounting portion configured to receive one end of a respective said coil suspension mechanism, wherein said pair of arms and at least a portion of the body adjacent the recessed portion are configured such that there is defined a space for accommodating the differential,

35. A kit of parts which can be assembled to convert a two-wheel drive vehicle to a four-wheel drive vehicle, comprising:

coil suspension mechanisms;

lateral and longitudinal axle constraints; and

a sub-frame mountable to a chassis of the vehicle, the sub-frame having:

a shaped central^' body adapted to extend transverse to a longitudinal axis of the vehicle and adjacen to the live axle, the body including a recessed portion and engine mounts adapted for receiving an engine for the vehicle; and

opposed pairs of mounting arms extending from opposite ends of the central body, each pair of mounting arms being provided with a mounting portion configured to receive one end of a respective said coil suspension mechanism, wherein a said pair of arms and at least a portion of the bod adjacent the recessed portion define a space for accommodating the .differential,

36. A method of converting a two-wheel drive vehicle to a four-wheel drive vehicle, comprising installing the kit according to any one of the preceding claims in the vehicle, whereby said space accommodates said differential or the differential housing is located in said space.

37. A method according to claim 36, including:

removing a sub-frame provided to support the engine from the chassis in the two- wheel drive vehicle; and

removing suspension of the vehicle at an end of the vehicle at which the con versior) being effected,

38. A method according to claim 36 or 37, including securing the body to the chassis,

39. A method according to claim 38, wherein the body is secured to the chassis at preexisting fastener connection points provided on the chassis.

40. A method according to any one of claims 36 to 39, including fixing the engine to the body.

41. A method according to any one of claims 36 to 40, including removing shock absorber mounts or towers, or portions thereof, at an end of the vehicle at which the conversion is being effected, before installation of the spring mounts.

42. A method according to claim 41 , wherein said shock absorber mounts or towers comprise wishbone mounts.

43. A method according to any one of claims 36 to 42, wherein the kit accords with any^¬ one of claims 1 to 33 and wherein the strut supports, spring mounts, live axle and lateral and longitudinal constraints are preassembled and thereafter installed.

44. A method according to any one of claims 36 to 43, including installing a steering arrangement or means which .comprises a steering bo and a link arrangement to impart steering to the wheels from the steering box at the end of the vehicle at which the conversion is being effected.

45. A method according to any one of claims 36 t 43, including fitting a steering arrangement or means which comprises a rack-and-pinion. steerin mechanism to impart steering to the wheels at the end of the vehicle at which the conversio is being effected

46. A method according to claim 45, wherein the rack is mounted to the live axle.

47. A method according to clai 46, wherei the rack is mounted to a housing cover of th differential of the live axle.

48. A method accordin to any one of claims 36 to 47, wherein the live axle is provided with anti-roll bar linkages, each of which is positioned adjacent a respective lateral end of the live axle, and wherein respective ends of an anti-roll bar are connected to said linkages.

49. A method according to any one of claims 36 to 48, wherein an anti-roll bar is mounted adjacent a forward end of the chassis.

50. A method according to any one of claims 36 to 49, wherein the two-wheel drive vehicle is a rear-wheel drive vehicle and the engine is front-mounted in the vehicle.

51, An assembly comprising the parts of a kit according to any one of claims 1 to 35. installed to convert said two-wheel drive vehicle to said four-wheel drive vehicle.