BACKGROUND ART The following description of the prior art is not intended to be, nor should it be interpreted as, an indication of the common general knowledge pertaining to the invention.

There are many hand-drawn vehicles on the market which are adapted to assist a person in carrying loads by foot. Examples include prams, typically including wheels with airless rubber tyres or narrow inflated tyres, similar to those of a bicycle, supermarket trolleys, and wheelbarrows generally supported by a single front wheel and rear stand.

However, such hand-drawn vehicles are generally unsuited for travel over difficult terrain such as soft sand and attempts to do so typically end in frustration and varying degrees of damage to the vehicle.

Other hand-drawn vehicles include wheels having a wide surface contact area. For an example, see US 4,538, 657 (Tuggle) which describes a thin-walled tyre with a torus of elastomeric material having an inner hub of certain axial length. Whilst such a tyre may be suitable for transport over soft surfaces, it is impractical for transport over hard surfaces, such as pavement due to the high surface area of the wheel in contact with the ground surface.

Accordingly, there is a need for an all-terrain vehicle adapted to overcome one or more ofthe abovementioned disadvantages in the prior art or at least provide a useful alternative to existing vehicles.

SUMMARY OF INVENTION h one aspect, the invention provides a dual wheel arrangement for an all-terrain vehicle suitable for use as a foot-drawn carraige for transport of recreational to a destination such as the beach and adapted to travel over bother hard surfaces and sand, the dual wheel arrangement including :

a wheel with a low pressure tyre which is flexible and readily deforms elastically at low pressure and is adapted to substantially flatten to form a relatively large surface contact area with a support surface such as the ground when under load; and adjacent to the first wheel, a second wheel with a diameter which is substantially consistent whether or not the second wheel is under load and a substantially constant width substantially smaller than the width of the low pressure tyre.

In another aspect of the invention there is provided : a dual wheel arrangement for an all-terrain vehicle, said dual wheel arrangement including a first wheel having a first hub and a first low pressure tyre with a first diameter and first width when not under load, wherein: a) the first tyre is flexible and readily deforms elastically at low pressure ; b) the first tyre is adapted to substantially flatten to form a relatively large surface contact area with the support surface such as the ground, floor or other transport surface when under load, whereby the diameter of the first wheel decreases significantly under load, the dual wheel arrangement further including a second wheel adjacent to the first wheel, the second wheel having: c) a second diameter which is substantially consistent whether or not the second wheel is under load; and d) a second substantially constant width substantially smaller than the first width. hi another aspect of the invention there is provided: a dual wheel arrangement for an all-terrain vehicle, said dual wheel arrangement including a first wheel of a first diameter when not under load, the first wheel including a first hub and a first low pressure tyie wherein : a) the first tyre is flexible and readily deforms elastically at low pressure; b) the first tyre is adapted to substantially flatten to form a relatively large surface contact area with the support surface such as the ground, floor or other transport surface when under load, the dual wheel arrangement further including a second wheel coaxial and adjacent to the first wheel and having ; 6 c) a second diameter which is greater than the first diameter, the second diameter being substantially consistent whether or not the second wheel is under load ; and d) a second width substantially smaller than the first width.

In another aspect of the invention there is provided : a dual wheel arrangement for an all-terrain vehicle, said dual wheel arrangement including a first wheel of a first diameter when not under load, the first wheel including a first hub and a first low pressure tyre wherein : a) the first tyre is flexible and readily deforms elastically at low pressure ; b) the first tyre is adapted to substantially flatten to form a first contact surface with a relatively large surface contact area with the support surface such as the ground, floor or other transport surface when under load, the dual wheel arrangement further including a second wheel adjacent to the first wheel, the second wheel having: c) a second diameter which is substantially consistent whether or not the second wheel is under load ; and d) a second width substantially smaller than the first width, whereby the first wheel is height adjustable such that, in a hard surface position, the respective contact surfaces of the first and second wheels substantially lie in the same general plane parallel to the support surface or the lowermost portion of the first wheel lies in a plane parallel to and above the general plane of the support surface and, in a soft surface position, the first contact surface lies in a plane parallel below the plane in which the lowermost portion of the second wheel lies.

The first tyre may include a first thin layer of material having the properties of unreinforced natural rubber and may deform at a temperature similar to or the same as natural rubber.

Because of the flexibility of the material with which the first tyre is made, when not under load, it may be substantially circular in cross-section.

The second wheel may include a hard ground contacting surface such as a hard-wearing metal or plastic material. The second wheel may be integrally formed from such hard-wearing material. The material may be steel, preferably stainless steel, or a polymer or copolymer material such as polypropylene, high density polyethylene, high molecular weight polyethylene or polycarbonate.

The second wheel may include a second hub and a second tyre. The hub may be made from materials such as those described above, namely preferably stainless steel, or a polymer or copolymer material such as polypropylene, high density polyethylene, high

molecular weight polyethylene or polycarbonate. The second tyre may be an airless tyre made of a rubber, natural or synthetic, polymer or copolymer material such as polypropylene, high density polyethylene, high molecular weight polyethylene or polycarbonate. Alternatively, the second tyre may be inflated in a manner similar to inflated wheelchair or bicycle tyres.

Preferably, under load, the second wheel may be used to support the all-terrain vehicle on a hard transport surface through which the second wheel is adapted not to penetrate. Preferably, the first wheel is adapted to support the all-terrain vehicle on a soft transport surface through which the second wheel is adapted to penetrate, but which the first wheel is adapted to travel across with minimal penetration.

The second tyre may be relatively hard but resilient whereby to travel efficiently over a hard transport surface such as asphalt, bitumen, pavement, rock, hard clay or unmade roads and to elevate the first wheel above the ground and out of contact therewith, but to permit the operation of a brake means operable by virtue of the resilience of the second tyre. That is, the first wheel is preferably suspended above a hard ground surface and does not support the vehicle. The first tyre preferably is an air-inflated tubed or tubeless rubber or rubber-like tyre, or an air-less rubber or rubber-like tyre.

The first tyre may be made from natural rubber formed from blow moulding or any other suitable process. Preferably the second tyre is of a narrow gauge. The difference between the first and second diameters when not under load is preferably minimal.

Advantageously, the second wheel causes minimal drag through soft transport surfaces such as sand, mud, fine dust, snow, water and the like.

The second wheel may be located on either side of the first wheel. The first wheel may be centrally located and a pair of second wheels located coaxial adjacent the first wheel on either side thereof. The first wheel may be on the inside or the outside of the second wheel where the dual wheel arrangement includes a pair of first and second wheels.

Preferably, the dual wheel arrangement includes a pair of first and second wheels in coaxial alignment.

In an alternative arrangement according to the invention, the first and second wheels are not coaxial. They may be mounted for rotation about axes adjacent and parallel to one another. For example, the first wheel may be located forward or rearward of the second wheel. The vehicle may be supported for travel over a hard surface by a pair of spaced and

coaxial second wheels mounted for rotation towards the rear of the vehicle. The first wheel may be mounted forward of the pair of second wheels, £or example at or near the centre of balance.

The first wheel may be retractable whereby to be height adjustable. Accordingly, where the support surface is solid or hard, the first wheel may be retracted so that its lower most portion lies in a horizontal plane above and clear of the support surface. Where the support surface is soft, the first wheel may be lowered to engage the soft ground and to lift the second wheel out of contact with the ground. The height adjustment means may be a mechanical device and a range of arrangements wit ! immediately occur to the skilled person, such as that used for adjusting the height of motor mower bodies, collapsible pram wheels and jockey wheels on trailers, and may include powered means such as a small pneumatic, hydraulic or solenoid arrangement.

The first tyre may include a first tube. The first tube may be made of a first thin layer of material having the properties of unreinforced rubber including being flexible-and readily deformable elastically at low pressure ; The cross-sectional shape of the first tube taken through a section of the first tyre parallel to the axis of rotation of the wheel is generally substantially circular when not under load due to minimal reinforcement ; The first tube may be used without reinforcement or strengthening and still achieve satisfactory performance. However, preferably the first tube includes a second outer predominantly ground contacting layer of material to improve durability and optionally provide tread, and therefore terrain, differentiation, The first and second layers may be made from a wide variety of materials, depending on the intended application. For example, very different materials will be suitable for a wheel for use in freezing conditions such as on snow. Such conditions require materials which maintain flexibility and are brittle resistant in close to (water) freezing or sub-zero temperatures. Compare this to hot climates where the first wheel may come into contact with hot surfaces such as asphalt, pavements, sand, dust, dirt, stone, rock or other ground material. The material required for such hot surfaces must have a relatively high melting point to avoid permanent distortion. or deformation in such an environment. Where the first wheel includes the second layer, it is preferred that the first and second layers be made from

materials sharing similar thermal expansion coefficient properties to avoid tearing or other damage to the structure.

The second layer preferably includes reinforcement to improve durability. Preferably the reinforcement is in the form of fabric reinforcement embedded in or otherwise associated with a rubber material. The fabric strands preferably are aligned circumferentially around the tyres outer surface. However, reinforcement parallel or diagonally traverse to the first wheel axis or radially aligned reinforcing may also be advantageous.

The tyre is adapted to perform when inflated to a low pressure and is preferably adapted to perform at pressures of between I and 10 psi. Preferably the tyre is adapted to perform optimally at about 1 to 3 psi and most preferably at 2 psi, it being understood that, in use, ambient and ground surface temperatures may affect the operating tyre pressure.

The hub may include a shallow circumferential recess to receive the inner tyre surface. Preferably the hub includes rounded rims to reduce the incidence of damage. Such damage may include punctures or structural weakening in the inner and outer side walls of the tyre immediately adapted to bear on the respective inner and outer rims. The hub may be bisymmetrical relative to a plane transverse to the axis of the hub and extending through the centre thereof. Preferably, the hub is formed from two parts adapted to be clamped, bolted or otherwise engaged whereby to secure the hub parts together.

The first tyre may be formed by blow moulding or any other suitable process. The tyre may be formed fyom a rubber or composite rubber material.

In another aspect of the invention there is provided: an all-terrain vehicle including step transversing means whereby the all-terrain vehicle includes : a) a front wheel means at or located towards a front end of the all-terrain vehicle, the front wheel means being adapted to engage a support surface such as a ground, floor or other transport surface; b) a rear wheel means at or located towards a rear end of the all-terrain vehicle ; c) a step traversing means angled tangentially from the lower ground engaging area of the rear wheel means extending up towards the rear end, said step traversing means inclined relative to the horizontal.

The step traversing means may be in the form of a skid means and may consist of a lower pane ! of a luggage carrying tub mounted on the first and/or second wheel means and the vehicle may comprise a corresponding monocoque construction. The skid means may include one or more skis, slides or skids. Preferably the skid means includes two parallel skids located either side of the all-terrain vehicle.

The step traversing means preferably includes a movable contact surface. The movable contact surface may comprise an endless belt extending between at least two spaced guide wheels. Preferably the endless belt is mounted under tension to ensure the belt position intermediate the wheels is able to support the load of the vehicle against the stairs or steps.

Stairs or steps typically incline at an angle of no more than 30 degrees and, accordingly, the step traversing means is preferably inclined to the horizontal at an angle of about 30 degrees, preferably in the range of 20 to 40 degrees.

The all-terrain vehicle may include handle means to enable an operator to tow or push the vehicle. The handle means may have an inverted"U"shape in a manner similar to handles commonly found on motor mowers. The handle means may be T-bar or L-shaped.

The handle means may be collapsible or removable when not in use and for compact storage or transport of the vehicle. The handle means may be retractably receivable within storage means such as a sleeve, track or channel. The handle means may slide linearly within the storage means. The storage means may be pivotable and/or lockable in position.

Preferably, the handle means is retractable or collapsible by the operation of a lockable rotational joint such as may typically be found on beach umbrellas or motor mowers- The handle means may be located or engageable at either or both ends of the vehicle.

Preferably, the handle means is located or engageable at the rear end of the vehicle. The handle means may be located at the end of the vehicle with the largest diameter ground-contacting wheels where the front and rear wheel sets vary, comparatively, in size.

The all-terrain vehicle may include various accessories depending on the particular application. For example, the all-terrain vehicle may include table means for picnics or as a mobile work or food preparation bench. The table means may include functional recesses or other moulding or features to secure crockery, utensils and the like. The all-terrain vehicle may include an umbrella holder, for example in the form of a substantially vertically aligned tube or sleeve or a ting or U-shaped feature for receiving the umbrella. The all-terrain

vehicle may include a child's seat or other support such as a baby capsule or toddler seat for carrying a child safely on the all-terrain vehicle.

The vehicle may include a carriage or carrying means for supposing or containing the items to be transported. The all-terrain vehicle preferably includes a tray for carrying a large array of items. For example, an ice fridge or esky, surf boards, a picnic basket, picnic or beach rug, camping or fishing equipment or any items required to be transported by the all-terrain vehicle across terrain or to locations which are not easily crossable or accessible using other hand drawn vehicles such as prams.

The tray may be in the form of a tub, such as a suitably dimensioned plastic container. The tray may be collapsible or may include a collapsible component. The tray may include a collapsible frame. The tray may include flexible material extending between and attached to the frame to define the internal tray volume or part thereof. The material may be rubber or rubber like material, plastic or cloth.

It has been discovered by extensive experimentation by the inventor to identify the best tray arrangement that a cloth material mounted under tension at a specific orientation achieves advantageous properties. Accordingly, the cloth material may comprise woven material with a weave set at a 45 degree angle mounted on the frame to resist stretching and maximise strength in two or more dimensions or directions. Preferably the cloth matexial is canvas or nylon fabric.

The cloth material may be attached to the frame by two or more stays or struts. The stays may be located intermediate the lengths of the frame components and/or at the corners.

The stays preferably are located at at least three anchor points on the tray. The stays may be located on the sides and the rear of the tray.

The stays may include any device capable of generating a compressive force, such as a buckle or jack. The buckle may be adjustable in length and/or orientation to accommodate variations in manufacturing tolerances and changes in componentry shape through wear, tear and the passage of time. The buckle may be an axially adjustable tumbuckle or other tcnsioiung or compressive device.

In a preferred manufacturing process, the upper frame is in the form of circular (cross-sectional) tubing which is fed through a corresponding shaped seam in an edge of the fabric designed to receive the zipper frame. The lower edge of the fabric to be attached to the upper rim of the tray has a similar seam defining a conduit through which a flat

U-shaped frame member is fed. The flat frame member is then bolted or riveted to the rim of the tray.

When the fabric is tensioned by the stays, the weave of the cloth is set at 45 degrees causing the upper frame to be erected substantially rigid relative to the top of the tray.

The frame may be made of any suitable material according to the application. For example, the frame may be made of substantially rigid plastic or metal material. Preferably the frame is lightweight, and may be made of aluminium.

The hand-drawn all-terrain vehicle may be powered by a small motor to facilitate its travel. The motor may be an electric motor powered by batteries andJor by solar power such as by the use of battery power charged by solar cells. The motor may be a combustion or electric hybrid engine. The motor may be driven, for example, by a small petrol or other fossil fuel powered engine. The motor may be operable to drive a pair of first and second wheels and/or the step climbing means.

The vehicle may include brake means. The brake means may be adapted to bear on the second wheel. Preferably the second wheel has some resilience operable to enable the brake to toggle from a first non-braking position to a second braking position. The brake means may include a cam mechanism. The brake means preferably includes an overcentre mechanism. The overcentre mechanism may include a plurality of linkages including fixed and floating articulated joins relative to the tray. The brake means preferably is adapted to take advantage of the resiliency of the second wheel to move between the first and second positions. The brake means may include a tyre engaging member adapted to indent the resilient tyre in moving to the second position.

BRIEF DESCRIPTION OF DRAWINGS To assist with the understanding of the invention, a number of embodiments will be described with reference to the following drawings. It is to be understood that the illustrated and specifically described embodiments of the invention are merely illustrative, non-limiting and in no way restrict the scope of the invention as broadly described hereabove.

Figure 1 is a schematic side view of an all-terrain vehicle according to one embodiment of the invention ; Figure 2 is a top plan view of the embodiment shown in Figure 1 ; Figure 3 is a rear end view of the embodiment shown in Figure 1 ;

Figure 4A is a side view of an all-terrain vehicle according to another embodiment of the invention ; Figure 4B is a top plan view of the embodiment shown in Figure 4A ; Figure 4C is an end view of the embodiment shown in Figure 4A; Figure 4D is a side view of the embodiment shown in Figure 4A collapsed for storage or transport ; Figure SA is a side elevation of a step climber according to another embodiment; Figure SB is a top plan view of the step climber shown in Figure 5A ; Figure 5C is an end view of the step climber shown in Figure SA ; Figure 5D is a schematic sectional view of part of the step climber shown in Figure 5A ; Figure 5E is a schematic side view of part of the step climber shown in Figure 3A ; Figure 5F is a partial end sectional view of a step climber according to another embodiment, Figure SO is a partial side sectional view of the step climber shown in Figure 5F ; Figure 5H is a partial end sectional view of a step climber according to another embodiment ; Figure 6 is a side plan view of an all-terrain vehicle according to another embodiment of the invention ; Figure 7 is a front elevation of the embodiment shown in Figure 6; Figure 8 is a top plan view of the embodiment shown in Figure 6; Figure 9 is a side elevation of the all-terrain vehicle according to another embodiment of the invention ; Figure 10 is a top plan view of the embodiment shown in Figure 9; and Figure 11 is a rear elevation of the. embodiment shown in Figure 9.

DETAILED DESCRIPTION OF DRAWINGS Referring to Figure 1, there is shown an all-terrain cart 10 including a receptacle or tub 20 for carrying items to be transported. The tub 20 is supported on a frame 30, in turn mounted on a set of rear wheels 40. A pair of retractable front wheels 50 are pivotably mounted on the frame 30.

The front jockey wheels 50 are mounted on a pivotable jockey frame 51 which may be releasably locked in either a ground contacting position or in a retracted position as

shown in Figure I. The front jockey wheels 50 are releasably locked by the operation of a clamp 52 comprising a pair of engageable concentric disks with intermeshable teeth, such as may be found commonly in articulated beach umbrella stands.

Extending at an inclined angle upwardly from the frame 30 is an articulated handle 31 which permits an operator to draw or push the vehicle 10 as required. The handle 31 is articulated about a rotatable joint 32 which is teleasably lockable over a range of angles of inclination suited to a particular operator and enables the handle 31 to be collapsed against the top rim 21 of the tub 20 for transport in the boot or trunk, for example, of a car or automobile. The handle may have an inverted"U"shape as shown in Figure 3, or the handle 31 may be of a T-bar or L-bar construction in which the primary shaft alone connects a handgrip 34 to the joint 32.

When the jockey wheels 50 are in the retracted position, the cart 10 is adapted for transport up and down steps or stairways by the operator by the combined operation and support of the rear wheels 40 and a pair of skids 33 upwardly and forwardly inclining tangemially from the lowermost portion of the rear wheels 40. The pair of skids 33 enable the cart 10 to be moved up and down steps by the sliding action of the skids across the apices of each step whilst the rear wheels 40 ride over each apices of each step, of course, by rotation thereover. It will be appreciated that this is a preferred arrangement compared to furniture removal trolley arrangements comprising triple pivotal axles due to the undesirable loud noise created by such furniture trolleys and the high impact nature upon each step occasioning undesirable wear and tear and possible damage to the stair surface and structure. Accordingly, it is within the scope of this invention that this aspect of the invention be considered in its own right as applicable to hand manoeuvred trolleys or barrows useful for wide ranging applications, including furniture removal where such trolleys and barrows are required to traverse stairs or steps. It will further be appreciated that the cart 10 may be in the form of a frarneless tray in which the wheels are mounted directly to the tub 20 in a monocoque construction, whereby the skids 33 are substituted by a front inclined panel or wall of the tub 20 which is adapted to directly bear upon the apices of each step.

As best seen in Figure 2, the front set of wheels 50 includes a pair of jockey wheels 53 located on either side of the frame 30. The rear set of'wheels 40 includes a first pair of low pressure wide wheels 41 and a second pair of narrow, substantially non-defomiable

wheels 42 on the outside of each corresponding low pressure wheel 41. The low pressure and narrow wheels 41,42 are coaxial mounted on a single axle 43. The narrow wheels 42 are slightly larger in diameter than the low pressure wheels 41 whereby, on hard ground surfaces, the narrow wheels 42 alone engage the ground surface. The low pressure wheels 41 are suspended above the ground and thereby do not create any significant drag as the cart 10 traverses the hard ground surface. In one particularly preferred construction, the diameter of the narrow wheels 42 is 300 mm, whereas the diameter of the low pressure wheels 41 when not under load is preferably 295 mm.

When the cart 10 is required to traverse a soft, yielding and penetrable ground surface such as soft sand or mud, the larger diameter narrow gauge wheels 42 of course penetrate the soft surface and the cart 10 sinks into the soft surface to a level whereby the low pressure wheels 41 support the cart 10 in ground engaging contact, Because the low pressure wheels 41 have no capacity to penetrate the soft surface to a significant degree, the low pressure wheels travel efficiently over the soft surface with minimal drag. Although the narrow wheels 42 penetrate the soft ground surface, their narrow width minimises drag.

Accordingly, in trials conducted by the inventors, it has been found that a pair of narrow wheels 42 in the form of soft spoked pram wheels have only a 5% impact on rolling resistance.

It will be well appreciated by the person skilled in the art that the rear wheel arrangement 40 may include a number of different arrangements which would satisfactorily achieve the desired result. For example, the narrow wheels 42 could equally be located on the inside of the low pressure wheels 41 with little impact on performance. The placement of the narrow wheels on the outside of the rear set of wheels 40 is desirable predominantly from an aesthetic view point because their larger diameter obscures the view of the inner low pressure wheels 41. Moreover, the rear wheel arrangement 40 performs satisfactorily with a single centrally positioned low pressure wheel 41. However, for balance and stability, a dual wheel type arrangement with a single low pressure rear wheel 41 still requires a pair of outside narrow wheels 42.

As shown in Figure 3, it is desirable to maximise the tub 20 interior space by locating the floor 22 as low as possible without admitting the possibility that heavy items retained in the tub 20 cause sagging of the floor 22 to such an extent that the floor 22 comes into frictional contact with the axle 43. To reduce the likelihood of this occurring,

particularly over time and extended use, the tub floor 22 may be provided with reinforcing ribs to resist sagging. The floor 22 may also extend lower than the axle 43 and be configured to provide a recess or slot through which the axle 43 extends to further enhance the volume capacity of the tub 20. Care, however, must be taken to ensure there is sufficient clearance between the floor 22 and a soft ground surface. To ensure that the wheels 41, 42 are located within the plan foot print of the tub 20, at least the low pressure wheels 41 are located within recesses 23 formed in the manufacture of the tub 20, including the moulding or working of the tub 20 during manufacture.

To assist in manoeuvrability of the cart 10, the outside nanow wheels 42 are also located within the plan footprint of the tub 20 extended by the provision of a reinforcing lip or collar 24 which extends around the periphery of the top edge of the tub 20.

The low pressure wheel 41 shown in Figure 1 includes a thin non-reinforced wall tube about 2mm thick. The tube is mounted about a hub. The tube is made from rubber or a material comprising rubber like properties and is adapted to be flexible and resiliently deformable. Moreover, the tube is preferentially inflated to a very low pressure of about 2 psi whereby to ensure minimal penetion of the wheels 41 on soft ground surfaces. At such a low inflation pressure, the external ground engaging surface of the tube is adapted to flatten to present a large ground engaging surface area relative to the overall volume occupied by the toroidal portion of the wheel 41. When not under load, the tube assumes a relatively circular cross-sectional shape-However, when under load, the tube easily compresses and flattens out. It is considered that this flat configuration providing the first tyre with a wide contact surface area combined with the low inflation pressure considerably enhances the minima ! drag performance of the low pressure wheel 41 over soft ground surfaces.

To increase the wear resistance of the tube, the external surface is fitted with a second extra layer of fabric reinforced rubber having cords running circumferentially. This permits different treads to be applied to the tube as determined by the intended application of the cart 10 as well as strengthening and improving the durability of the tube. As the second reinforcing rubber layer does not extend fully around the torus of the tube, it does not interfere with the deformability of the side walls thereof and correspondingly does not significantly reduce the large surface ground contact area assumed by the flattened tube under load.

14 an alternative arrangement according to one embodiment shown in Fig. 4F, the first and second wheels 120,130 are not coaxial. They are mounted for rotation about axes adjacent and parallel to one another. The first wheel is located forward of the second wheel.

The vehicle is supported for travel over a hard surface by a pair of spaced and coaxial second wheels mounted for rotation towards the rear of the vehicle. The first wheel is mounted forward of the pair of second wheels at or near the centre of balance of the vehicle.

In another embodiment, the first wheel is retractable whereby to be height adjustable.

Accordingly, where the support surface is solid or hard, the first wheel is retracted so that its lower mbst portion lies in a horizontal plane above and clear of the support surface. Where the support surface is soft, the first wheel is lowered by an operator to engage the soft ground and to lift the second wheel out of contact with the ground. The height adjustment means is a threaded mechanical device that used for adjusting the height of a jockey wheels on a trailer. In Fig. 4F a track 122 shown in Fig. 4E is shown in greater detail and explained with reference to Figs. SA to 5l snd, the cart 121 may be rocked back to lift the front wheel off the ground whilst maintaining the rear second wheel pair 130 clear of the ground.

With reference to Figures 4A to 4D, another embodiment of a vehicle 60 according to the invention is shown. The vehicle 60 includes a dual rear wheel arrangement 61 and a front single wheel 62 rotatably mounted on a frame 63 Also mounted on the frame is a step climber 64 and brake 65. Extending upwardly from the frame 63 is a handle 66 including a convenience pocket 67 extending laterally between spaced bars 68 of the handle 66. The handle 66 extends over a tray 70 and is articulated about a lockable hinge 69, whereby to lock the handle 66 in a range of different inclinations and positions, including a fold down horizontal position.

The tray 70 is a moulded plastic tub of strong abrasion resistent plastic material such as polypropylene or high density polyethylene which is of sufficient thickness to withstand extended use and may have a wall thickness of 2 to 5 mm, with wall join areas being thicker to give the tray 70 added rigidity.

The internal volume and carrying capacity of the tray 70 is extended by a collapsible upper wall 71 comprising a flexible woven material attached to an upper floating frame 72.

In use, the upper frame 72 is supported above the tray 70 by spacing means in the fom of turn buckles 73 which are axially adjustable to ensure that the extension wall 71 is held

under tension. The turn buckes 73 may be engaged at their upper and lower ends to the upper frame 72 and tray 70 by simple angled ends inserted in complementary bores 74 in the upper frame 72 and tray 70, respectively. To collapse the extension wall 71 and the upper e 72, the upper and lower ends of the turn buckle 73 may be disengaged from the bore 74 so that the upper frame 72 spaced to fit inside the tray 70 when collapsed, rests snuggly within the tray 70. The vehicle 60 should include at least 3 turn buckes 73 located on each side of the tray towards the front 75 and a single turn buckle 73 located centrally at the rear of the tray 70 to give the upper frame 72 adequate stability and support. Regarding the strength, rigidity and stability of the material wall 71, it has surprisingly been found that if the cloth 71 is mounted so that its weave extends at an angle 45'to'the horizontal these positive properties are maximise. The inventor has found that the wall 71 is surprisingly less rigid when the weave is oriented along vertical and horizontal lines relative to the frame members.

A lid 76 may be provided on the upper frame 72 and may extend partially across the top of the upper frame 72 as shown in Figure 4A or may extend fully across the opening defined by the upper frame 72.

Turning specifically to Figure 4B, the dual wheel arrangement 61 includes first wide wheels 61 a having a large ground contacting surface area adapted to travel across the top of soft surfaces such as sand and mud without penetrating the ground surface. The wide wheels 61a are located on the inside of a pair of outer narrow wheels 61b. The wide wheels 61a and narrow wheels 61n are all mounted on the same axle 61c extending laterally underneath the lower frame 63 and mounted thereto by (as is standard in the axt).

The diameter of the wide wheels 61a when not under load is marginally smaller than the diameter of the narrow wheels 61b so that on hard surfaces, such as pavement, the vehicle 60 rests on the narrow wheels 61b. The narrow wheels 61b include a hard rubber tyre 61 d mounted on a hub and rim 61e of correspondingly narrow width. The hub 61e includes radiating spokes in the form of blades extending between the hub and the rim. On soft terrain, such as sand or mud, into which the narrow wheel 61b is adapted to penetrate, the hub and rim 61 e is adapted to cut through the soft ground material to minimise frictional resistance as the wide wheels 61a support the vehicle 60 for travel over the soft ground.

The operator may lean downwardly on the handle 66 to lever the vehicle 60 so that the front

end 75 rocks upwardly about the axle 61c to take the weight off the front wheel 62 to ensure that the front wheel 62 does not retard the progress of the vehicle 60.

In Figure 4C the dual wheel arrangement is shown in transverse section through a vertical plane parallel to the axle 61c The wide and narrow wheels 61a, 61b are mounted for rotation on the axle 61 c and secured in place by easy to remove wingnuts 61 e threadably engaged with a corresponding threaded end of the axle 6 1 c on either end. Alternatively, the wingnuts 61e could be replaced by quick release cam locks as commonly used to releasably secure front wheels of bicycles to the bicycles front hub. On the inside of each of the wide wheels 61 c are step traversers 61 f..

In Figure 4D the collapsible nature of the vehicle 60 is shown in which the handle 66 is folded so that it rests predominantly within the tray 70. The dual wheel arrangement 61 is fully removed together with the front single wheel 62, the step climber 64 is also removed.

By so collapsing the handle 66, it reduces the volume of the vehicle 60 for transport or storage as much as is practically possible.

In Figure 4B there is shown a brake means 65 including a brake bearing member 65a adapted to indent the narrow tyre 61d when the brake means 65 is activated. The brake means 65 includes a pair of fixed linkage points 65b, 65c and a pair of movable articulated joins 65d, 65e. The movable join 65d operates as the indenting brake member and the movable join 65e operates as the over centre mechanism movable between a braking and non-braking position and held in place in either position by the resilience of the tyre 61d.

The brake is operated by simple foot pedal 65f. The brake means 65 is fixed directly to a formed recess in the underside of the tray 70 and may be bolted or riveted to the lower frame.

In Figure 5A, the step climber 64 according to a first embodiment 64a includes a pair of spaced, parallel and opposed identical plates, preferably made of metal such as aluminium or stainless steel for corrosion resistance and strength. The step climber 64a includes a track section 64b and a mounting bracket section 64c. The opposing plates are rigidly secured together in spaced relationship by anyone of a vanety of standard means, such as bolt means with internal spaces, rivets or other similar fasteners and preferably located at the points marked"X"opposed plates 64b. Interposed between the opposed plates is the track section 64g, having first and second ends 64d, 64e.

Mounted on the track section 64g is a linked chain 64f adapted to travel in a channel extending about the periphery of the track section 64G. The track section 640 defines a track having a shallow channel through which the chain is adapted to travel. The pitch of the chain 64f is sufficiently high whereby the links of the chain 64f extend proud beyond the profile of the track section 64g and the opposed plates 64b, whereby the links make direct contact with the surface of steps in use. The low *Mon coefficient of the track section 64g ensures that the chain 64f travels easily across its surface and minimal deterioration of performance is noticeable where sand and other debris enter the channel of the insert 64g.

The step climber 64a is mounted at an angle of inclination of 30° to correspond to typical step inclinations and the top end 64h is mounted to the lower frame 63 at the rear end of the vehicle 60 and the mounting bracket 64c is secured to the axle 61c through a bore 64i.

Referring to Figures 5F and 5G, the insert may alternatively made from stainless steel, Teflon, or ultra high molecular weight polyethylene and a substitute for the link chain 64f may be a rubber or woven belt 64j for making surface contact with the stair to be climbed. Interposed between the rubber belt 64j and the insert 64g may be a plurality of discrete bearing tabs 64k having a low friction coefficient. Accordingly, the tabs 64tray be made from stainless steel, Teflon or ultra high molecular weight polyethylene, preferably stainless steel. The insert 64g may define a channel through which the tabs 64k travel as shown in Figure 5H or the tabs 64k may themselves define channels which straddle the insert 64g. Where the tabs 64k are stainless steel, they may be vulcanised to the rubber belt 64j for strong adhesion.

Referring to Figures 5D and 5E, an alternative. arrangement of the step climber 64 is shown in which the pair of opposed plates cover only the mounting bracket section 64e. In Figure 5E the opposed mounting bracket plates are shown fixedly fastened to each other by bolts in which the respective plates are spaced by spacers interposed between the internal surfaces of the opposed plates. The linked chain 64f travels easily in a continuous loop about the shallow channel defined by the insert 64g made from a low friction coefficient material such as stainless steel, ultra high molecular weight polyethylene or Teflon.

In Figure 6 there is shown another embodiment of the vehicle according to the invention comprising a trolley 80 having a frame 81 on which are mounted rear support wheels 82 and 6 ; ott retractable castor wheels 83. The portion of the frame 81 extending

from the rear support wheels 82 to the front retractable castors 83 is set at an angle of inclination of about 30° which is the typical maximum angle of inclination of sets of stairs.

However, it will be appreciated that this angle of inclination of the skids of frame 81 may be varied depending on the specific intended applications.

It can be seen that the handle 84 is articulated around a beach umbrella/lawn mower style handle joint 85 and that the handle may be rotated around the joint 85 through various angles including a £old down position 86 suitable for storage.

The trolley 80 may be configured in a step climbing mode in which the retractable castor wheels 83 are swivelled upwardly to a non-ground engaging position 87 in which the retractable castors 83 will not interfere with the step climbing operation.

As best seen in Figure 7, the larger diameter narrow wheels 42 may be located on the inside of the low pressure wheels 41, (like reference numerals being used to refer to like components shown in Figures 1 to 3).

Figure 9 shows a vehicle 100 according to a third embodiment of the invention. The vehicle includes a tray 101 mounted on a chassis or frame 102 and supporting a collapsible carrier extension 103. At the front end of the vehicle 100 is a single central wheel 104 having a relatively small diameter. Towards the rear of the vehicle is mounted a pair of opposed spaced sets of wheels 105 substantially as described in relation to wheels 41, 42 in Figure 2. Extending from between each of the sets of wheels 105 at au inclined and upward angle of about 30 degrees towards the rear of the vehicle is a step traversing caterpillar 106.

Caterpillar 106 comprises a pair of spaced lower and upper guide wheels 107,108 which are adapted to hold a continuous belt 109 under tension to support the load of the vehicle when traversing stairs or irregular terrain, such as rocky pathways.

Also mounted to the frame 102 is an adjustable handle 110 similar to handle 31 described in relation to Figure 1.

It can be seen that carrier 103 comprises an upper frame made of aluminium tubing (25 x 1.6 mm) which extends around the upper periphery of the vehicle and has a footprint substantially identical to or at least similar to that of the tray 101. An upper frame portion 111 defines the upper peripheral edge of the carnage 103. Adjustably and selectively collapsibly supporting the upper frame portion l l l are inclined frame supports 112. The frame supports may be made from a variety of lighter weight materials, such as 6 mm spring wire.

In its erect position, the frame ! 11 holds the nylon fabric 113 under tension whereby to deSne a canier area having an extended volume canying capacity. Of course, when the frame 112 is collapsed, the cloth walls 113 fold down conveniently to facilitate transport of the vehicle 100, for example, in the boot of a car or automobile. It will be appreciated that in this collapsed state, the handle 110 is advantageously folded down on top of the collapsed carrier 103. Preferably the cloth walls 113 are made from a woven fabric which may be nylon. The nylon fabric is advantageously oriented in the erect state of the carriage 103 so that the weave extends at about 45 degrees to the horizontal. This weave orientation is effective to minimise the extent of stretching as a result of the wear and tear which the fabric walls 113 are subjected to during extended use.

The caterpillar belt 109 is preferably made from a plastic materials or rubber composite or rubber like materials similar to those used to forrn the wheels 105. The guide wheels 108 are similarly made from hard plastic or light weight metal materials such as polypropylene or aluminium.

UTILITY OF INVENTION The vehicle, cart or trolley (for convenience, referred to hereinafter as"the cart") may be used to carry goods and accessories to and from places of leisure. The cart may include accessories such as a table forming a lid to the tub tray, or carrier (hereinafter"the tub"), and an umbrella holder, fishing rod holder, baby capsule and/or toddler seat. The tub may be used to carry small eskies, beach umbrellas/igloos, beach rugs, one or more boogie boards, towcls/togs/wetsuits, bags, picnic baskets, rubbish bags, reading material, surfboards and may be adapted to carry marine equipment such as surf skis.

The cart 80 is easy to push/pull over paved areas, including kerbs, soft sand, grass, mud, snow, rough/steep bush tracks, and regular or irregular steps. The cart may be fitted to create a facility for use at the beach, fishing, picnic spot by providing a stable, elevated food/drink/preparation table with drink, plate, utensil holders, fixtures for securing umbrellas, rubbish storage or fishing rod holders and many other accessories as may be apparent to the person skilled in the art.

To enable easy manoeuvrability by a wide range of foot-mobile persons, it is desirable that the cart be a maximum of 15 kilograms in weight, dimensioned to fit through a standard doorway (780-800 mm) and easily stowed in a car boot, such storage being facilitated by detachable andlor collapsible tub, frame, wheels, accessories and handles.

The cart may be suitable for use by people wishing to visit the beach and other recreational locations by car thereby requiring a collapsible easily stored and transportable luggage cart, by families living within close proximity to beaches and other recreational areas, by fishermen, by people who have on-site vans, holiday homes, or those who frequent camping grounds for extended holiday periods and have a requirement to carry items to and from their place of leisure.

The frame 30,81, 111, 112 may be made from suitable strong and corrosion resistant materials such as reinforced polymeric material (e. g. polypropylene), aluminium or steel.

The hub of the rear low pressure wheels 40,82, 105 and the axle 43,143 may be made from similar materials. The tub or tray may be made from similar materials, but preferably is made from a mouldable, abrasion resistant polymeric material such as high density polyethylene.

The preferred vehicle or cart may provide the following features and advantages : 1. A hand propelled vehicle which makes picnicking more pleasant

2. A hand cart which reduces the effort required to transport picnic gear over paved surfaces, soft sand and steps.

3. A hand cart which creates increased amenity at the picnic spot in the form of a food preparation table, rubbish receptacle and umbrella support.

4. Travel over various terrain, surfaces by means of two pairs of dual wheels, conventional 30 psi pnemnatic and adjacent 2 psi low pressure tyres slightly smaller in diameter (low pressure tyres not in contact with hard surface).

In another aspect of the invention, there is provided a high tension woven structure adapted to maximise strength and tension of the structure in two or more directions or dimensions, the structure including : a frame defining two or more boundaries of a woven material held under tension, the weave including interwoven fibres extending at right angles relative to one another wherein the weave or fibres of the material is oriented at an angle of 45"to at least one of the boundaries.

When used in this specification and claims, the tenn$"comprises"and"comprising" and variations thereof mean that the specified features, steps or integers are included. The terms are not to be interpreted to exclude the presence of other features, steps or components.