GB2562052A

GB2562052A - A wheel extension

Info

Publication number: GB2562052A
Application number: GB1706940.2A
Authority: GB
Inventors: T Taylor Scott
Original assignee: Terrain Tec Ltd
Current assignee: Terrain Tec Ltd
Priority date: 2017-05-02
Filing date: 2017-05-02
Publication date: 2018-11-07
Anticipated expiration: 2037-05-02
Also published as: GB2562052B; WO2018189733A1; GB201706940D0

Abstract

A wheel extension 100 for retrofitting to the wheel of a vehicle so as to distribute the weight of the vehicle over a larger surface area. The wheel extension 100 comprises an attachment means (Fig 1A, item 240) for attaching the wheel extension to a wheel 500, and a plurality of spars 200 for at least partially enclosing a volume of space dimensioned to receive a bladder 400. The spars 200 are connected to the attachment means (240).

Description

(71) Applicant(s):

Terrain Tec Limited

The Granary, Rempstone, Corfe Castle, WAREHAM, Dorset, BH20 5JQ, United Kingdom (72) Inventor(s):

Scott T Taylor (56) Documents Cited:

EP 1943107 A2 DE 002940604 A1 (58) Field of Search:

INT CL B60B, B60C Other: WPI & EPODOC

DE 020318409 U1 JP 2005119626 A (74) Agent and/or Address for Service:

ipconsult

21A Commercial Road, SWANAGE, Dorset, BH19 1DF, United Kingdom (54) Title of the Invention: Awheel extension Abstract Title: Awheel extension (57) Awheel extension 100 for retrofitting to the wheel of a vehicle so as to distribute the weight of the vehicle over a larger surface area. The wheel extension 100 comprises an attachment means (Fig 1A, item 240) for attaching the wheel extension to a wheel 500, and a plurality of spars 200 for at least partially enclosing a volume of space dimensioned to receive a bladder 400. The spars 200 are connected to the attachment means (240).

400

FIG 3

100

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

06 17

300

06 17

A Wheel Extension

Field of the Invention

The present invention relates to a wheel extension. More specifically the present invention relates to a wheel extension for retrofitting to the wheel of a vehicle so as to distribute the weight of the vehicle over a larger surface area.

Background of the Invention

When crossing soft ground such as mud or sand, the wheels of vehicles may sink into the ground. This impedes progress of the vehicle, and may result in the vehicle becoming stuck or bogged down.

In order to prevent this occurring, vehicle users have had to replace their wheels, or the tyres thereof with specialised wheels with increased surface areas so as to distribute the weight of the vehicle over a larger surface area.

This is time consuming, and may be expensive or require specialised tools in addition to the specialised wheels.

The present invention provides a wheel extension which may be retrofitted to a wheel quickly and easily so as to increase its effective surface area, thereby distributing the weight of a vehicle over a larger surface area and improving its performance on soft ground.

Another aim of the invention is to provide a wheel extension which may be retrofitted to a wheel without complicated tools or specialist wheel changing equipment so that the wheel extension can be fitted in situ.

Summary of the Invention

According to a first aspect of the invention there is provided a wheel extension for spreading the load of a vehicle comprising: an attachment means for attaching the wheel extension to a wheel, and a plurality of spars connected to the attachment means, the spars at least partially enclosing a volume of space dimensioned to receive a bladder.

In use, wheel extensions may be attached to one or more wheels of a vehicle by the attachment means and one or more bladders are arranged within the volumes of space at least partially enclosed by the spar lengths. The bladder filled extensions act to increase the effective surface area of the wheels to which they attached, thereby distributing the weight of the vehicle over a larger surface area.

Spars may be elongate members, such as bars, arms or strips of material, which may be bent, curved or otherwise shaped such that they may be arranged to define and/or at least partially enclose a volume of space. Ideally the spars are arcuate and/or shaped to engage with, and/or attach to the wheel; and/or to retain and/or at least partially surround the bladder. The spars may be formed from, or may comprise a composite material, such as a carbon fibre laminate material; metal, such as steel or aluminium; a synthetic plastics material; a carbon fibre reinforced polymer; or any combination of these materials.

Spars may be directly connected to the attachment means, or may be connected to another element, such as an adaptor, comprised by the extension which are connected to the attachment means.

In other embodiments, individual spars may be connected to individual elements of the attachment means, and the combined spars and elements of the attachment means may be separated by other components of the extension. The connections may be rigid, such that the location and orientation of the spars, with respect to the attachment means, is fixed; alternatively, the connections may allow one, some, or all of the spars to be displaceable with respect to the attachment means. For example, the connections may comprise hinges or other mechanical bearings which allow the orientation and/or the location of the spars with respect to the attachment means, or components thereof to be adjusted. Such an adjustable arrangement allows the at least partial enclosure of the volume of space to be opened and closed, for example to facilitate the installation of a bladder therein.

In alternative embodiments, the spars and the attachment means may be formed integrally with each other, and/or individual spars may be formed integrally with individual components of the attachment means.

The volume of space at least partially enclosed by the spars may be enclosed to the extent that when a bladder located within the volume of space is inflated to substantially fill the volume of space, the spars retain the bladder within the volume of space. The volume of space may be enclosed to the extent that a bladder substantially fills the volume of space, such that in order to remove a bladder it has to be at least partially deflated. In some embodiments, the spars may entirely enclose the volume of space and may be connected one to another at their distal ends.

Other components of the extension may also form part of the at least partial enclosure of the volume of space. For example, the extension may comprise a plate from which the spars extend. The plate may define an end boundary of the volume of space with the spars defining boundaries for the volume extending from the plate.

The spars preferably define a cage for retaining the bladder within the volume so that the boundaries of the cage ideally at least partially enclose the volume. For example, in some embodiments the extension may comprise a plurality of spars which in use extend away from the wheel and which curve or bend such that their ends meet at a point away from the wheel, thereby defining a cage. The distal spar ends may be adjacent one another; may contact one another; may be fixed to, or may be releasably attached one to another. In some embodiments, the cage may entirely enclose the volume of space.

In use, the volume of space at least partially enclosed by the spars may be substantially circularly symmetric about an axis of rotation of the wheel. This allows a substantially circularly symmetric bladder to be installed in the volume of space, and the overall wheel extension to be substantially circularly symmetric. This also allows the wheel extension to increase the surface area of a wheel without undue negative impacts on the performance of the wheel.

The volume of space may be located adjacent to, may extend from, and may be at least partially enclosed by the outer face of the wheel.

In some embodiments, one, some, or all of the spars comprise s first portion for at least partially enclosing the volume of space and a second portion for engaging with the wheel.

The second portions of the spar may attach the extension to a wheel. They may surround, partially enclose and/or interlock with all of, portions of, or individual components of the wheel.

In some embodiments, the second portions may be comprised by, or may constitute the attachment means. Alternatively, or additionally, the attachment means may comprise clamps, ties, screws, grips, bolts, washers, hooks, straps, and/or magnetic or interference fit attachment means, which may attach the extension to the wheel.

The first and second portions may be distinct, may be separated by some other portion of the spar, or may overlap, such that a portion of the spar engages with the wheel and forms a part of the at least partially enclosure of the volume of space. The spar portions may be lengths of the spars.

In some embodiments, the first portions may be at, or may extend from first ends of the spar, and the second portions may be at, or may extend from second ends of the spar.

The first portions may be for enclosing, or partially enclosing the volume of space, for retaining or locating the bladder, may extend from the outer face of the wheel and may define a cage which may enclose the volume of space and may retain the bladder.

The second portions may locate the wheel extension with respect to the wheel, may engage with the wheel such that the wheel extension rotates with the wheel, and/or may attach the wheel extension to the wheel. In some embodiments, the second portions may cover a portion of the rim of the wheel, may engage directly with the tyre of the wheel and may thereby attach the wheel extension to the wheel.

The wheel extension may comprise a spar retainer which may engage with the spars intermediate their first and second portions. In alternative embodiments the spar retainer may engage with the first portions of the spars, with the second portions of the spars, in an overlapping region comprised by both the first and second spar portions.

The spar retainer may engage with the spars when the wheel extension is assembled, when the wheel assembly is attached to the wheel, and/or when a bladder is inflatable within the volume of space defined by the spars. In some embodiments, the spar retainer may be disengage-able from the spars. The spar retainer may be disengaged from the spars in order to attach the wheel extension to a wheel, for example to allow second portions of the spars to displaced such that they can fitted around the wheel or such that a bladder may be inserted into the volume of space at least partially enclosed by the spars.

The spar retainer may retain the spars in an arrangement where first portions of the spars at least partially enclose the volume of space, and the second portions of the spars engage the wheel. For example, the spar retainer may press the second portions of the spars against portions of the wheel, such that the spars are braced in a position where the first portions of the spars at least partially enclose the volume of space.

In some embodiments, the spars may be fixed to, be releasably connected to, interlock with, or fit through apertures in the spar retainer. The spars may be rigidly arranged with respect to the spar retainer, or may be displaceable with respect to the spar retainer, the spars may be linearly displaceable between a plurality of locations in contact with or engaging with the spar retainer, may be displaceable into and out of contact or engagement with the spar retainer, and/or the spars may pivot about the spar retainer.

In some embodiments, the spar retainer may be actuated so as to disengage with and/or release the spars. When the spars are released by the spar retainer, the extension may be released from the wheel, and/or a bladder contained within the volume of space may be released from the spars. The spar retainer may be actuated so as to disengage with and/or release the spars, by opening one or releasable connectors, thereby either disassembling the spar retainer or releasing connections between the spar retainer and the spars, alternatively the release/disengagement may be actuated by a controlled detonation.

In some embodiments, the wheel extension comprises a spar retainer releasing means. The spar retainer releasing means may be a means of breaking the spar retainer, for example the spar retainer may comprise explosive which may be detonated automatically or remotely in order to sever a spar retainer ring. Such an arrangement enables rapid release of the attachment means, ideally whilst the vehicle to which they are connected is still moving.

The spars may comprise bends intermediate their first and second portions which engage with the spar retainer.

The insides of the bends may define indentations in the outer surface of the spars inside which elements of the spar retainer may be arranged thereby interlocking the spars with the spar retainer. An element of the spar retainer may contact the insides of the bend and press the spars against some other objects, such as the wheel, the bladder, or another element of the spar retainer. The presence of an element of the spar retainer within the inside of the bend may prevent the spars from being displaced out of an arrangement where they are attached to the wheel and/or where they are retaining a bladder within the volume of space defined by the first portions of the spars.

The spar retainer may comprise, protrusions, hooks, bars or other elements which in use are inserted into, or located within the inside of the bend so as to retain the spars.

The spars may be pivot-able about the elements of the spar retainer located inside the bends. The wheel extension may be thereby arranged such that when the second portion of a spar is displaced outwards (away from the axis of rotation of the wheel) the first portion is displaced inwards (towards the axis of rotation of the wheel). Therefore, the presence of the wheel within the second portions may prevent the first portions being displaced outwards, and/or the presence of an inflated bladder within the first portions may prevent the second portions from being displaced outwards.

The spar retainer may act as a fulcrum about which the spars are pivotable.

For example, the wheel extension may be attached to a wheel with the bladder either uninflated or absent from the volume of space. This may allow the first portions to be displaced inwards, thereby displacing the second portions outwards such that they can fit around the wheel. The bladder may then be inserted into, or inflated within the insides of the first portions, thereby pressing them outwards, pressing the second portions inwards against the exterior of the wheel and attaching the wheel extension to the wheel. The wheel extension may then be removed by either deflating the bladder, or releasing the spar retainer.

In some embodiments, the spars and/or the bladder may be shaped and/or arranged such that the bladder (or a portion thereof) contacts the outer face of the wheel when located and/or inflated within the spars or first portions thereof. When the bladder is inflated within the spars and/or first portions thereof the bladder may exert a force or pressure upon the outer face of the wheel. This may displace the wheel attachment outwards along the axis of rotation of the wheel, and/or may press elements of the wheel attachment which engage with the inner surface of the wheel (such as elements of second portions of the spars) against the inner surface of the wheel (or a tyre comprised thereby).

In alternative embodiments, the spars may comprise other elements specifically shaped to engage with the spar retainer, such as hooks, apertures, loops or other engagement means.

In some embodiments, the spar retainer may be a shaped band of material and may be a ring or other closed loop. The closed loop or ring may be circular, or may comprise a plurality of corners or vertices. The number of corners or vertices may be equal to the number of spars, for example the spar retainer comprised by a wheel extension with four spars may be square, diamond, superellipse, or squircle shaped.

The closed loop or ring may surround the spars in use, may engage with indents or attachment means comprised by the spars, or may pass through apertures through the spars.

In some embodiments, the spar retainer may be tubular and may engage with a portion of the length of the spars. In some embodiments, the spars may comprise an elongate portion between the first and second spar portion which may be surrounded by a tubular spar retainer. The tubular spar retainer may be cylindrical, or may comprise a cross section with a plurality of straight edges which may extend along the length of the spar retainer. The spar retainer may comprise a number of edges equal to the number of spars, for example a tubular spar retainer comprised by a wheel extension with four spars may be cuboid, and/or may have a square, diamond, superellipse, or squircle shaped cross section.

The spar retainer may separate the volume of space enclosing first spar portions and/or the bladder from the wheel. In some embodiments, the spar retainer may space the first spar portions apart from the wheel along the axis of rotation of the wheel, for example so as to prevent the bladder or the spars from contacting the wheel arch of a vehicle when turning.

Wheel extensions may be provided with differently dimensioned spars and/or spar retainers; and/or which space apart the first portions of the spars and/or the bladder out different distances along the axis of rotation of the wheel. For example, wheel extensions for attachment to the front wheels of vehicles may space the first spar portions and/or bladder out further such that it does not contact the wheel arch when the front wheels are turned during steering.

The portions of the spars with which the spar retainer engages may have a lower radius (as measured from the axis of rotation of the wheel) than the first and or second portions of the spars. This may prevent this portion of the wheel extension which may be located adjacent to the outer face of the wheel, from contacting the wheel arch of a vehicle in use.

Ideally the spar retainer may comprise, or may be formed from a flexible or deformable material, such as a composite, wire or fibre, and is resiliently deformable. This may accommodate stretching of the spar retainer and may enable impact and/or shock absorption.

The size of the spar retainer may be adjustable, for example to allow the same set of spars to be attached to differently sized wheels. The length, radius, and/or circumference of a ring, closed loop, or tubular shaped spar retainer may be adjustable. Alternatively, the spar retainer may be replaceable with one or more differently sized and/or dimensioned spar retainers.

The spar retainer may have an adjustable diameter by way of a circumferential adjuster. Alternatively, or additionally, the spar retainer may be supplied in different lengths or may be adjustable lengthwise in order to accommodate various sized wheels. In some embodiments, the fulcrum about which the spars are pivotable may be provided by a ring, or a spacer bracket or another type of anchor point which may engage with the spars and/or the wheel.

The spar retainer may be, or may comprise, a spacer bracket which may lengthen the spar retainer and so hold the first spar portions and/or the bladder at a distance away from the wheel thereby ensuring that the arcuate portions of the spars and the bladder do not contact or impinge upon the wheel arches of the vehicle, which might otherwise impede steering.

In some embodiments, the spar retainer may be attachable to the wheel, for example the spar retainer may comprise ties, brackets, clips, clamps, bolts, or washers which engage with wheel nuts.

In some embodiments, the spar retainer may be a ring which may surround the spars, may contact the outer surfaces of the spars and may be located within the inside of bends comprised by the spars, thereby engaging with the spars. The ring may thereby maintain the spars against the wheel and/or a bladder located within the volume of space at least partially enclosed by the first portions of the spars.

The ring may be located against, near to, adjacent to, and/or in a parallel plane to the outer face of the wheel.

In alternative embodiments, the spar retainer may be, or may comprise a chain, a tie, a plurality of rings or closed loops, or a body with a plurality of spar retaining means such as clips or apertures.

In some embodiments, the spar retainer is circularly symmetric about an axis of rotation of the wheel. The spar retainer may thereby retain the spars in a circularly symmetric arrangement and the entire wheel arrangement may thereby be circularly symmetric so as to improve the efficiency of the wheel.

In use the spars may be distributed around the circumference of the spar retainer, the circumference of the wheel, and/or the circumference of a cross section through the bladder orthogonal to the axis of rotation of the wheel.

In some embodiments, the profile of the spars may comprise an arcuate or substantially semi-circular length, connected to a first substantially straight length by a substantially full angled bend, the first substantially straight length being connected to a second substantially straight length by a substantially right angled bend, and the second substantially straight length being connected to a third substantially straight length by a substantially right angled bend.

The arcuate or substantially semi-circular length may be comprised by the first portion for at least partially enclosing the volume of space, the substantially full angled bend may be comprised by the spar locator engaging element, and the first, second and third substantially straight lengths may be comprised by the second portion for engaging with the wheel.

In some embodiments, the attachment means may comprise a plurality of spar portions for engaging with the wheel.

The spar portions comprised by the attachment means may attach the wheel extension to a wheel. They may surround, partially enclose and/or interlock with all of, portions of, or individual components of the wheel. Alternatively, or additionally, the attachment means may comprise clamps, ties, screws, grips, bolts, washers, hooks, straps, and/or magnetic or interference fit attachment means.

In some embodiments, one, some, or all of the spar portions comprised by the attachment means may be portions of the spars for at least partially enclosing the volume of space comprised by the wheel extension. The spars comprised by the wheel extension may comprise portions which engage with the wheel and portions which at least partially enclose the volume of space, these portions may be distinct, or may overlap.

Alternatively, the spar portions comprised by the wheel extension may be comprised by different spars to those which at least partially enclose the volume of space. One, some or all of the spars which comprise the spar portions comprised by the wheel attachment means may be attached to one, some or all of the spars for at least partially enclosing the volume of space. Alternatively, both sets of spars may be connected to one or more other elements of the extension, such as a plate or ring which separates the volume of space from the attachment means.

One, some, or all of spar portions comprised by the attachment means may comprise substantially U-shaped portions. In some embodiments, the spar portions comprised by the attachment means may be substantially U-shaped spar portions. In some embodiments, the U-shaped portions may be the second portions of the spars.

The U-shaped portions may be U-shaped brackets. The U-shaped portions may be for engaging with a wheel or portions thereof, for example the U-shaped portions may be for, or may be dimensioned to receive or fit over the rim or tyre of a wheel.

The attachment means may comprise a plurality of U-shaped spar portions which fit over the rim or tyre of a wheel at a plurality of points around its circumference so as to secure the wheel extension to the wheel.

In use, substantially U-shaped portions of the spar portions comprised by the attachment means may contact the inner face, rim and outer face of the exterior of a wheel.

The U-shaped portions of the spar portions may be adjustable in size, for example the width of the U-shape may be adjustable so as to allow the U-shaped portions to fit securely around the rims of a variety of differently sized wheels.

The base of the U-shape of the U-shaped portion may define a ground contacting portion, which may in use be arranged over the ground contacting portion of the wheel (such as the rim or a portion of a tyre). The ground contacting portion may be substantially flat, may have treads or grips formed on its outer surface and may be adjustable in width so as to fit onto wheels of different sizes.

The spar portions comprised by the attachment means may be shaped such that in use they contact the inner face of the wheel, the rim of the wheel and the outer face of the wheel.

In some embodiments, the spars, or first portions thereof may be arcuate. The arcuate spars or spar portions may be semi-circular. The arcuate spars or spar portions may be dimensioned to at least partially enclose a volume of space to enclose a substantially rounded bladder, and/or may be dimensioned to retain a substantially rounded bladder.

The volume of space enclosed by the spars, or first portions thereof may be substantially spherical, cylindrical, conical, frusto-conical, capsule-shaped, or superegg-shaped.

The boundaries of the volume of space may be defined and/or at least partially enclosed by the spars or first portions thereof, by the spar retainer and/or by the outer face of the wheel. For example, in an embodiment where the volume of space is substantially cylindrical, one flat end wall of the cylindrical volume may be defined by the outer face of the wheel, by a ring-shaped spar retainer held against the outer face of the wheel by the attachment means, and by a plurality of spar lengths which extend substantially radially from the spar retainer. The radially extending spar lengths be bent by approximately 90 degrees before extending outwards from the wheel parallel to the axis of rotation of the wheel, so as do define the curved wall of the cylindrical volume. The end of the spars may be bent by approximately 90 degrees to extend radially inwards towards the axis of rotation of the wheel so as to define the distal flat end of the cylindrical volume.

The bladder received by the volume of space may be substantially spherical, cylindrical, conical, frusto-conical, capsule-shaped, superegg-shaped, and/or of substantially the same shape as the volume of space when inflated.

The volume of space may be adjacent to, may be coaxial to, may extend from, and/or may be at least partially defined and/or enclosed by the outer face of the wheel.

The spars may be substantially flat and may be arranged such that a normal to the flat surface of the spar lies within the plane which contains both the axis of rotation of the wheel and a central lengthwise axis of the spar.

The spars may be substantially flat or planar. Therefore, the spars may comprise flat surfaces for contacting the ground, for contacting the outer surfaces of the wheel, and/or for contacting the outer surfaces of the bladder. In use the spars or first portions thereof may conform to and/or be coplanar with the outer surface of the bladder, and spar portions comprised by the attachment means may conform to and/or be coplanar with the outer surfaces of the wheel.

The outer surfaces of the spars (those facing away from the axis of rotation of the wheel) which in use contact the ground may have treads formed thereon. These may include portions of the spars which contact the furthermost radially extending (from the axis of rotation of the wheel) portions of the bladder, and portions which contact the rim of the wheel.

In some embodiments, more of, a majority of, or all of the outer surface of the spars may have treads formed thereon. In some embodiments, all of the outer surface of the first portion of the spars may have treads formed thereon and/or all of the outer surface of the spar portion comprised by the attachment means may have treads formed thereon.

Alternatively, or additionally the outer surfaces of the spars or first portions thereof may have fins and/or paddles formed thereon.

The spars or first portions thereon may comprise flexible portions which may extend from their first ends, or the ends distal from the wheel and the attachment means.

Flexible spars may allow the wheel extensions to more effectively absorb shocks or to absorb the unevenness of off-road terrain.

In some embodiments, the attachment means may attach to the rim of the wheel, to the spokes of the wheel, to the hub of the wheel, or to any combination thereof. The attachment means may comprise spar portions which interlock with the wheel or components thereof, may comprise clamps, grips, or ties which may be secured to components of the wheel. Alternatively, or additionally the wheel connector may comprise washers and/or bolts which may allow the wheel extension to be screwed onto a wheel, for example the wheel attachment means may comprise washer portions through which the bolts which secure a wheel to a vehicle may be inserted such that these bolts also secure the wheel extension to the wheel.

The wheel extension may comprise three or more spars. In preferred embodiments, the wheel extension comprises at least four spars.

The spars may be substantially flat. In some embodiments, the spars may be formed from flat strips of material which may be bent about axis perpendicular to the length, width and/or the axis of rotation of the wheel, so as to adopt a shaped profile which may at least partially enclose a volume of space, may retain a bladder, may interlock with the spar retainer, may engage with the wheel, and/or may attach the wheel extension to the wheel.

The spars may comprise, and/or may be formed from a composite material. Such a composite material may be a carbon fibre laminate material. The use of composite materials may allow all or a portion of the spars to flex.

In some embodiments, the spars may be adjustable, for example different length first spar portions may be used in combination with differently sized second portions for engaging with the wheels.

Differently sized spars may allow differently sized bladders to be used and/or may allow the wheel extensions to be attached to differently sized wheels.

In some embodiments, inserts may be provided, and/or comprised by the wheel extension which may be inserted into the attachment means, or spar portions thereof, so as to allow them to be used with differently sized and/or dimensioned wheels.

In some embodiments, in use the spars, first portions thereof, and/or the bladder may have a radius from the axis of rotation of the wheel substantially equal to that of the wheel, such that the wheel extension provides an extension for the wheel along the wheel’s axis of rotation. In alternative embodiments, the radius of the spars or first portions thereof, and of the bladder, from the axis of rotation of the wheel may be greater than that of the wheel. This may provide additional elevation with respect to uneven terrain or soft ground over which a vehicle is travelling.

The wheel extension may comprise a bladder which may in use be located inside the volume of space defined by the spars or first portions thereof. In use the wheel extension may retain the bladder within the spars or first portions thereof, the bladder may be retained adjacent the wheel so as to define an increased rotating surface area.

The bladder may be inflatable. In some embodiments, the bladder may be selfinflating and/or may comprise a plurality of isolated separately inflatable or selfinflating chambers, so as to minimise the risk of a puncture deflating the bladder. The bladder may be inflated by air, or some other compressed gas. In alternative embodiments, the bladder could be water inflatable.

The outer surface of the bladder may have treads formed thereon.

In some embodiments, the outer surface of the bladder and/or the outer surface of the spars may have fins formed thereon. The inflatable bladder retaining wheel extensions may allow a to which they are attached to float and to act as a waterborne or amphibious vehicle. The fins may provide traction and/or propulsion for the vehicle.

In some embodiments, the wheel extension may comprise one or more paddles, and/or one or more paddle wheels, which may be located at distal ends of spars from wheel, and/or intermediate the first and second portions of the spars. The paddles/ and or paddle wheels may provide propulsion to a waterborne vehicle when the wheels to which the extensions are affixed are rotated.

In some embodiments, the spars, first portions thereof, and/or second portions thereof may comprise a rim, lip or ridge which may extend from the outer surface of the spars. The rim lip or ridge may extend along the length of the spar or first or second portions thereof, may extend radially outwards (with respect to the axis of rotation of the wheel in use), and/or may be substantially at right angles to the outer surface of the spars. These rims, lips or ridges may provide additional traction on soft surfaces, for example on soft snow or powder.

In some embodiments, the bladder may comprise, or may be contained within a reinforced jacket. For example, the reinforced jacket may be reinforced with carbon fibres; graphene; and/or Kevlar (RTM). Alternatively, or additionally the bladder, or an outer surface thereof may be formed from a reinforced material; Kevlar (RTM); graphene; a carbon fibre fabric; or any combination thereof.

The outer surface of the reinforced jacket may have treads, grips, fins, rims, lips, paddles and/or ridges formed thereon.

In some embodiments the bladder, the outer surface of the bladder or the reinforced jacket may comprise connection means for engaging with or connecting to the spars, first portions thereof, the spar retainer, and/or the wheel. Alternatively, or additionally the spars, first portions thereof, spar retainer or wheel attachment means may comprise means for connection with the bladder, outer surface thereof, and/or the reinforced jacket. The connection means may be grips, clips, ties, magnets, hook and loop connectors, interlocking means, members and matching recesses, or any combination thereof.

In some embodiments, the spars, first or second portions thereof, the outer surface of the bladder, and/or of the reinforced jacket may comprise means to connect to their outer surface, such as attachment points for snow chains.

In some embodiments, the volume of space may be dimensioned to receive a plurality of bladders, the spars or first portion thereof may locate and/or retain a plurality of bladders. In some embodiments, the wheel extension may comprise a plurality of bladders which may have any of the optional features described above. The wheel extension may comprise bladder locating means which may be located within the volume of space and may be supported by the spars, by the attachment means, and/or by the spar retainer. One, some or all of the bladders may be modified, adapted, or comprise any of the features, as described above.

Preferred embodiments of the invention will now be described, by way of example, with reference to the Figures, in which:

Brief Description of the Figures

Figure 1A is an overall view of a wheel attachment comprising alternative extended spars attached to a wheel with the bladder absent;

Figure 1B is an overall view of a wheel attachment attached to a wheel with the bladder absent;

Figure 1C is an overall plan view of vehicle with four wheel attachments with extended spars attached, showing how the wheel attachments retain the bladders at a distance from the vehicle to facilitate turning;

Figure 2 is a second overall view of the wheel attachment attached to the wheel with the bladder absent;

Figure 3 is an overall view of the wheel attachment attached to the wheel with the bladder present;

Figure 4 is a first end view of the wheel attachment attached to the wheel with the bladder present;

Figure 5 is a second end view of the wheel attachment attached to the wheel with the bladder present;

Figure 6A is an overall view of a wheel attachment removed from the wheel and disassembled with two of the spars removed;

Figures 6B and 6C are overall views of the spars removed from the partially disassembled wheel attachment shown in Figure 6A;

Figure 6D is an overall view of an alternative extended spar comprising an extended recess portion for retaining the bladder at a distance from the vehicle;

Figure 7 is an overall view of a vehicle being driven across soft terrain without the use of wheel attachments; and

Figure 8 is an overall view of a vehicle being driven across soft terrain with wheel attachment fitted to each wheel.

Detailed Description of the Figures

Referring to the figures generally there is shown embodiments of a wheel extension 100 according to the present invention comprising four spars 200, a ring-shaped spar retainer 300, and optionally an inflatable bladder 400. In use the wheel extension 100 may be attached to a wheel 500 so as to increase the effective surface are of the wheel 500, and thereby spread the weight of a vehicle to which the wheel is attached.

Figures 1B, 2, 3, 4, 5, 6A, 6B, and 6C show a first embodiment with shorter spars 200 (which are shown in detail in Figures 6B and 6C). Figures 1A and 1C show an alternative embodiment where the spars 200 have been replaced with alternative extended spars 200A (shown in detail in Figure 6D).

The spars 200 each comprise a first portion 220 for defining and partially enclosing a volume of space within which the bladder 400 is retained, a second portion 240 for engaging and connecting to the wheel 500, and a bend 260 which connects the first and second portions 220, 240 and which engages with the ring-shaped retainer 300.

The alternative extended spars 200A comprise similarly dimensioned first portions 220A for defining and partially enclosing the volume of space within which the bladder 400 is retained, and similarly dimensioned second portions 240A for engaging with and connecting the wheel 500. The alternative spars 200A further comprise elongate intermediate portions 260A which connect the first portions 220A and the second portions 240A, and which in use engage with the ring-shaped retainer 300 (or alternatively, multiple ring-shaped retainers 300, or a differently shaped retainer).

The spars 200, 200A are formed from flat elongate strips of material which are bent so as to have a shaped profile comprising the first portion 220, 220A, the second portion 240, 240A and the bend 260, or intermediate portion 260A. The material may be a carbon fibre laminate material.

The first portions 220, 220A of the spars 200, 200A are arcuate and extend between first ends 222, 222A of the spars and the bends 260, or intermediate portions 260A. In the illustrated embodiment, the first portions 220, 220A are substantially semicircular.

In use, the first portions 220, 220A of the spars 200, 200A surround a volume of space within which the bladder 400 may be retained. The spars 200, 200A may be distributed around the circumference of the ring-shaped retainer 300 and the circumference of the wheel such that the four first portions 220, 220A define a cage within which the bladder may be retained. The first ends 222, 222A of the spars 200, 200A meet at a point on the axis of rotation of the wheel 500 a distance away from the outer surface of the wheel 500.

When the bladder 400 is inflated within the first portions 220, 220A of the spars 200, 200A such that it fills the volume defined and partially enclosed by the first portions

220, 220A, the first portions 220, 220A are substantially coplanar with the outer surface of the bladder 400.

The second portions 240, 240A of the spars are U-shaped and extend between second ends 242, 242A of the spars and the bends 260, or the intermediate portions 260A. The U-shaped second portions 240, 240A comprise three substantially straight lengths connected by two substantially right angled bends.

In use the second portions 240, 240A engage with the rim of the wheel 500. The Ushaped portions 240, 240A fit over the rim or tyre of the wheel 500, such that they contact the inner face, the rim, and the outer face of the wheel 500. In use the second portions 240, 240A may be distributed about the rim of the wheel 500 so as to secure the wheel extension 100 to the wheel 500.

When the wheel extension 100 is attached to the wheel 500, the second portions 240, 240A may conform to and may be substantially coplanar with the outer surface of the wheel.

The end length of the first portion 220, 220A distal from the first end 222, 222A of the spar 200, 200A, runs substantially parallel to the end length of the second portion 240, 240A distal from the second end 242, 242A of the spar 200, 200A.

In the shorter spars 200, these two parallel end lengths are connected to each other by the bend 260 such that they define the sides of a notch formed in the outer surface of the spars 200 with which the ring-shaped spar retainer 300 may engage in use.

In the alternative extended spars 200A, these two parallel end lengths are connected to each other by the intermediate portion 260A of the spar. The intermediate portion 260A is substantially parallel to the middle length of the second portion 240A and the axis of rotation of the wheel 500, and is substantially at right angles to the two parallel end lengths which it interconnects.

The intermediate portion 260A separates the first portions 220A and the bladder 400 from the wheel 500 and the second portions 240A, locating the bladder 400 further away from the wheel 500. The alternative elongated spars 200A may distribute the weight of a vehicle over a larger area, and may prevent the wheel attachment 100 from contacting the wheel arch of vehicles during steering. In some circumstances, alternate extended wheel attachments 200A may be attached to the front wheels of a vehicle (such that they do not contact a wheel arch when the front wheels are turned during steering), and regular shorter wheel attachments 200 may be attached to the rear wheels. Figure 1C shows a vehicle with wheel attachments 100 comprising the alternative extended spars 200A attached to each of the front wheels 500, and wheel attachments 100 comprising the shorter spars 200 attached to each of the rear wheels 500.

The ring-shaped retainer 300 is a ring torus with a major radius approximately half that of the wheel 500 and slightly less than that of the inside of the bend 260, or intermediate portion 260A, and slightly less than half the width of the notch defined between the first portions 220 and the second portions 240 in the shorter spars 200.

In use, the four shorter spars 220 are inserted partially through the ring-shaped spar retainer 300 and are then engaged with the spar retainer 300, such that the spar retainer 300 is in contact with the insides of the bends 260 comprised by the spars 200. In this configuration, the spars 200 are able to pivot about the ring-shaped spar retainer 300, and are also able to be displaced around the circumference of the ring of the spar retainer 300.

When the alternative extended spars 200A are used, they are inserted partially through the ring-shaped spar retainer 300 (or in further alternative embodiments a tubular spar retainer) and are then engaged with the spar retainer 300, such that the spar retainer 300 is in contact with the outer surface of the intermediate portion 260A, between the first and second portions 220A, 240A of the spar 200A. The intermediate portion 260A defines an indent in the profile of the alternative extended spar 200A with reduced radius (from the axis of rotation of the wheel 500) within which the spar retainer 300 is retained.

In such an arrangement, the first ends 222, 222A of the spars 200, 200A are located near, adjacent and/or in contact with each other and a point on the axis of rotation of the wheel.

The wheel extension 100 may then be attached to a wheel 500, for example, by rotating the spars 200, 200A around the ring shaped spar retainer 300, until they are all on one side of the ring of the spar retainer 300, fitting the U-shaped second portions 240, 240A of the spars 200, 200A over the rim of the wheel, then rotating the spars 200, 200A back around the wheel 500 and the ring of the spar retainer 300, such that they are equally distributed around the circumference of the wheel 500 and the spar retainer 300 (such an assembled embodiment may be seen in Figures 1A, 1B, and 2). In this arrangement, the spars 200 hold the spar retainer 300 against the outer face of the wheel 500.

Alternatively, if the second portions 240, 240A are sufficiently large with respect to the wheel 500, the spars may be distributed around the circumference of the spar retainer 300 and then pivoted with respect to the spar retainer 300, such that the second portions 240, 240A are spread outwards, and the first portions 220, 220A are pushed inwards. The second portions 240, 240A may then be fit over the rim of the wheel 500 before being pressed against the wheel 500, thereby pivoting the first portions 220, 220A back outwards.

The bladder 400 may either be inserted before the spars 200, 200A are rotated back around to be equally distributed about the circumferences (in which case it may be inserted substantially inflated), or may be inserted between the spars 200, 200A after they have been distributed about the circumferences (in which case it must be inserted while substantially deflated). The bladder may then be inflated such that it expands and presses against the insides the of the first portions 220, 220A of the spars and against the outer face of the wheel 500.

The pressure exerted by the inflated bladder 400 on the outer face of the wheel pushes wheel extension 100 outwards along the axis of rotation of the wheel 500, and ensures that the parts of the second spar potions 240, 240A adjacent the second spar ends 242, 242A are pressed against the inner face of the wheel 500.

The pressure exerted by the inflated bladder 400 on the inner surfaces of the first portions 220, 220A of the spars 200, 200A press the first portions 200, 220A radially outwards away from the axis of rotation of the wheel 500. This causes the second portions 240, 240A of the spar 200, 200A to be pressed radially inwards against the rim of the wheel 500.

The pressure of the inflated bladder 400 thereby secures the wheel extension 100 to the wheel 500.

A wheel extension 100 comprising the additional elongated spars 200A may comprise a specially shaped bladder 400 which in use fills the space between and first portions of the spars 220, 220A, the intermediate portions 260A and the outer face of the wheel 500. This may allow or ensure that the bladder 400 presses against the outer face of the wheel 500 when it is inflated. Alternatively multiple bladders 400 may be used, for example a first approximately spherical bladder 400 located between the first portions 220A of the spars 200A, and a second approximately cylindrical bladder 400 located between the intermediate portions 260A.

Figure 7 shows a vehicle weighing approximately 1600kg with four tyres whose area of contact with the ground is approximately 25cm wide and 25 cm long. The pressure exerted on the ground by the vehicle is therefore approximately 16000/0.25 = 64000 Pa.

Figure 8 shows the same vehicle with a wheel extension attachment 100 attached to each tyre, thereby increasing the effective surface area in contact with the ground. The bladders 400 held by the wheel attachments are approximately spherical with a circular footprint with a diameter of approximately 0.75m. Each of the wheel extensions weighs approximately 25kg. The pressure exerted on the ground by the vehicle with the extensions attached is therefore approximately 17000/(0.25+1.767,..) = 8427.749... Pa.

Therefore, the vehicle fitted with the wheel attachments exerts only approximately 13.168...% of the pressure exerted by the vehicle without the attachments, thereby enabling it to be driven across much softer terrain with the attachments fitted than without.

It is understood that the invention is not intended to be limited to the illustrated embodiment described above, and any suitable modifications may be made to the described embodiment which fall within the scope of the invention as defined by the claims. For example, the illustrated embodiment may be modified to include optional features described in the summary of the invention. For example the invention may be deployed with amphibious vehicles or used to provide amphibious capability to non-amphibious vehicles.

Claims

1. A wheel extension for spreading the load of a vehicle comprising: an attachment means for attaching the wheel extension to a wheel, and a plurality of spars for at least partially enclosing a volume of space dimensioned to receive a bladder, wherein the spars are connected to the attachment means.

2. A wheel extension according to claim 1 wherein the spars define a cage for retaining the bladder within the volume of space.

3. A wheel extension according to claim 1 or claim 2 wherein the volume of space enclosed by the spars is substantially circularly symmetric about an axis of rotation of the wheel.

4. A wheel extension according to any preceding claim wherein each of the spars comprise a first portion for at least partially enclosing the volume of space and a second portion for engaging with the wheel.

5. A wheel extension according to claim 4 wherein the first portions are at a first end of the spar and the second portions are at a second end of the spar.

6. A wheel extension according to any of claims 4 or claim 5 wherein the first portions are for retaining the bladder and the second portions are for engaging directly with a tyre of the wheel.

7. A wheel extension according to any of claims 4 to 6 comprising a spar retainer which engages with the spars intermediate their first and second portions.

8. A wheel extension according to claim 7 wherein the spars comprise bends intermediate their first and second portions which engage with the spar retainer.

9. A wheel extension according to claim 7 or claim 8 wherein the spar retainer is circularly symmetric about an axis of rotation of the wheel.

10. A wheel extension according to any of claims 7 to 9 wherein the spar retainer is a ring.

11. A wheel extension according to any of claims 4 to 10 wherein the second portions of the spars are comprised by the attachment means.

12. A wheel extension according to any preceding claim wherein the attachment means comprises a plurality of spar portions for engaging with the wheel.

13. A wheel extension according to any of claim 11 or claim 12 wherein the spar portions comprised by the attachment means comprise U-shaped portions.

14. A wheel extension according to claim 13 wherein the U-shaped portions are dimensioned to receive a tyre comprised by the wheel.

15. A wheel extension according to any of claims 11 to 14 wherein the spar portions comprised by the attachment means comprise adjustable ground contacting portions.

16. A wheel extension according to any preceding claim wherein the spars or first portions thereof for at least partially enclosing the volume of space are arcuate.

17. A wheel extension according to any preceding claim wherein the volume of space enclosed by the spars or first portions thereof is substantially spherical, cylindrical, conical, frusto-conical, spherical, capsule-shaped, or supereggshaped.

18. A wheel extension according to any preceding claim wherein the outer surfaces of the spars or first portions thereof have treads, fins, and/or paddles formed thereon.

19. A wheel extension according to any preceding claim wherein the spars or first portions thereof for at least partially enclosing the volume of space comprise flexible portions.

20. A wheel extension according to any preceding claim wherein the attachment means attaches to the rim of the wheel.

21. A wheel extension according to any preceding claim wherein the attachment means attaches to the spokes of the wheel.

22. A wheel extension according to any preceding claim wherein the attachment means attaches to the hub of the wheel.

23. A wheel extension according to any preceding claim wherein the spars are substantially flat.

24. A wheel extension according to any preceding claim wherein the spars comprise a composite material.

25. A wheel extension according to any preceding claim wherein the spars are formed from a carbon fibre reinforced laminate material.

26. A wheel extension according to any preceding claim comprising a bladder which in use is located inside the volume of space.

27. A wheel extension according to claim 26 wherein the bladder is inflatable.

28. A wheel extension according to claim 26 or claim 27 wherein the bladder is self-inflating.

29. A wheel extension according to any of claims 26 to 28 wherein the bladder comprises a plurality of isolated separately inflatable chambers.

30. A wheel extension according to any of claims 26 to 29 wherein the outer io surface of the bladder has treads, fins, or paddles formed thereon.

31. A wheel extension according to any of claims 26 to 30 wherein the bladder is reinforced with carbon fibres, graphene, and/or Kevlar (RTM).

15

32. A wheel extension according to any of claims 26 to 31 wherein the bladder is contained within a reinforced jacket.

33. A wheel extension according to claim 32 wherein the jacket is reinforced with carbon fibres, graphene, and/or Kevlar (RTM).

34. A wheel extension according to claim 32 or claim 33 wherein the outer surface of the reinforced jacket has treads, fins, or paddles formed thereon.

35. A wheel extension according to any preceding claim for adapting a vehicle to

25 be amphibious.

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