NZ239667A - Foldable boat with retracting wheels - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £39667 PATENTS FORM NO. 5 Fee Xo. 4: $260.00 PATENTS ACT 1953 COMPLETE SPECIFICATION After Provisional No: 239667 Dated: 4th September 1991 A FOLDABLE STRUCTURE T if ■■■>> ■Vs I Denis Lee Stewart, a New Zealand citizen of 102 Avenue Road, Morrinsville, New Zealand hereby declare the invention for which I pray that a patent may be granted to me/us, and the method by which it is to be performed to be particularly described in and by the following statement: 1 £39 667 This invention relates to a foldable structure.

In particular but not exclusively, this invention relates to a foldable structure that may be folded for transportation and/or positioning at a site, or for storage, and unfolded for use. The invention may also include a means for supporting the structure to facilitate transportation and/or positioning of the structure at a site or storage area and means for supporting the structure in an operational configuration.

The invention may be particularly suitable as a floatable structure such as a boat that may be folded to a size suitable for towing on a road behind a vehicle, and opened to a floating configuration. However it is understood that the invention is not to be limited as such, and may be a structure of any form, which structure may be movable and/or foldable at some stage of its construction or use. Some typical embodiments may be as portable and/or foldable buildings, scaffoldings, mobile stages, advertising bill boards, dish antennas, solar furnaces, flying boats, hydrofoils and the like.

In general, in the case of buildings for example, to move and position a building it must first be lifted onto a trailer or fitted with a wheeled support and then moved to and positioned at the desired site. After positioning, the trailer or wheeled support is then removed so that the building can be lowered to the ground and fixed in position. In the case of a large building, depending on surrounding size restrictions, the building may need to be partially disassembled to a size suitable for transportation and then reassembled at the site. This is generally a labour intensive and expensive operation so that the location of buildings in certain areas may not be economical. Hence development of these areas may be limited.

Furthermore, regardless of the above difficulties, the development of an area may not be possible due to such factors as the access being restricted by a v.t r :'v. . no^r foundation conditions or certain building restrictions which jiivvt'::: ereciion of buildings having conventional foundations.

The inconvenience of fitting wheels to a structure to be moved may be overcome to s111ne extent with mobile structures such as caravans, mobile homes, and the hke wiure the structure is permanently fitted with wheels. However, in certain situations these structures also are limited in their use due to size restrictions.

Fo'dahie structures such as folding caravans and camping vans which may overcome some of the size restrictions are known. However, with these .structures the folding arrangement is general]}-' aimed at reducing only the height of the structure, so that there may still be a limitation on the width of the s: '-ucture. Furthermore, such structures are generally supported by wheels in both the folded mobile configuration and in the unfolded configuration. ('oriM iiuentiy there may be problems with obtaining adequate support for the structure when being used on soft ground for example. Also the loading capacity of the structure may be limited by the load bearing capacity of the wheels. Furthermore, since the wheels are generally loaded they are not easily removable and hence when used for extended periods in the open, there may be problems with deterioration of tyres, bearings etc.

In the ca.se of a floatable structure such as a boat that is capable of being towed on a road, this is generally of a fixed configuration and carried on a separate trailer attached to a towing vehicle. Due to the Fixed configuration of the boat, the maximum width, height and length of the boat are generally limited by such factors as road width and traffic regulations. Furthermore the size and configuration of the boat may causc problems due to excessive wind resistance and instability and the like when towing.

Another problem common to boats that are towed on a separate trailer is that once the boat has been launched, the trailer and towing vehicle must be parked <>39 6 6 trailer attached to a towing vehicle. Due to the fixed configuration of the boat, the maximum width, height and length of the boat are generally limited by such factors as road width and traffic regulations. Furthermore the size and configuration of the boat may cause problems due to excessive wind resistance and instability and the like when towing.

Another problem common to boats that are towed on a separate trailer is that once the boat has been launched, the trailer and towing vehicle must be parked and taken care of. There is also the disadvantage of the extra cost of the trailer, the sole purpose of which is to support and transport the boat when on the land.

Furthermore, once the boat has been launched, it can generally only be brought out of the water and taken away on its own trailer. Consequently it may not be possible to bring the boat out of the water and take it away at other locations. Also, since the width of a boat that is carried on a trailer is generally limited to the width of the trailer, the boat is not usually of sufficient width to carry its own trailer when floating on water and it may be practically impossible for it to carry the towing vehicle as well. The use of the boat is therefore generally limited to situations where the boat is launched and removed from the water at the same launching site, and propulsion is provided by a separate engine.. Furthermore, due to size restrictions, accommodation area on the boat is small so that use of the boat is limited.

To overcome some of the problems related to boats carried on trailers there have been proposals to fit removable wheels on fixed configuration boats. However the means for attaching the wheels is generally complicated and time consuming, and the wheels must be removed and stored when the boat is being used on water. at least two structural members pivotally connected together so as to be foldable relative to each other about a longitudinal axis of said structure, between an open configuration and a closed configuration of said structure, first support means comprising at least two support members disposed in substantially fixed spaced apart relation to each other, for movably supporting said structure when said structure is in said folded configuration, second support means for supporting said structure when said structure is in said open configuration and, respective connecting means for connecting each of said structural members to said first support means, with said pivotal connection disposed therebetween, the arrangement and construction being such that said first support means is accommodated within said structure when said structure is in said open configuration, and protrudes from said structure when said structure is in said folded configuration.

According to another aspect of the present invention, there is provided a foldable structure as aforesaid wherein said structural members comprise two hull sections, said first support means comprises a wheel assembly with at least two wheels acting as said two support members with axes of rotation substantially perpendicular to said longitudinal axis, and said second support means comprises floatable sections of said hull sections whereby said structure can be floatingly supported on water in said open configuration with said wheel assembly retracted into said structure.

According to yet another aspect of the present invention, there is provided a foldable structure as aforesaid wherein said structure is in the form of a boat, said hull sections being pivotally connected along a longitudinal central axis of said boat, and said wheel assembly comprises a transverse beam member with one or more wheels rotatably supported at each end, each of said hull sections being supported on said wheel assembly by the respective connect! -'.(.'iiun.- m.iy nn>ve relative 1 o said whet'! assembly as said hull -• <•::e:> art- folded and unfolded, and said wheel assembly may be supported by ,-a:c: bo.v. when said hull sections are floating in an open configuration.

According to yet another aspect of the present invention, there is provided a fo'.dable structure in the form of a boat substantially as aforesaid further comprising means whereby said boat may be towed behind a vehicle in said foided condition, and said hull sections are adapted to be able to support said towing vehicle when unfolded to said open condition and floating;on water.

Wit:: the foldable structure of this invention, since the structure'may be folded by folding structural members of the structure, the size of the structure may be r< dart d by folding for operations such as transportation, positioning and storing. As a result, si/.e limitations encountered with fixed configuration structures may be overcome. Furthermore, the provision of a first movable support means facilitates positioning and transportation of the structure. Since the structure may be supported in an open configuration by a second support means, loading on the first support means may be reduced or eliminated. Use of the structure may therefore not be restricted by the loading capacity of the first support means. Furthermore, since the first support means may be completely unloaded, and protected from the environment by the structure, deterioration of the first support means is minimized. J It is generally envisioned that the first support means would comprise wheels rotatablv mounted on axles so that the structure was movably supported by the wheels. However the first support means may be any kind of support for movably supporting the structure in a folded configuration. For example it may comprise skids which enable a certain degree of sliding movement relative to the ground.

S!::rt the first support means may he substantially unloaded when the structure is opened, then in the case of a wheeled support means it may be possible to easily remove the wheels without the need for additional jacks. This may he an advantage if the wheels are to be removed for storage or for use on another structure to be moved. >:::ce the structure may be supported by a second support means when in the opt-n configuration, the invention may be particularly suitable for structures such, as a mobile stage where the structure in the unfolded condition must support the additional weight of equipment and performers, or a temporary or i::oh:ie building such as a house which is to he located on soft ground or on an area subject to flooding. In these situations the second support means may rnmprise a large base section to spread the load over a large area so that the structure is adequately supported, and may even provide floatation if the area floods Furthermore where access is restricted by waterways the structure may be unfolded and floated across the water and then refolded for land t ransportatio n.

In the case of a foldable structure for floating on water such as a boat or pontoon fitted with a first support means comprising wheels, the hulls of the structure may he designed to provide sufficient floatation so that the wheels are located out of the water when the structure is in the opened configuration thereby minimizing deterioration of the wheels and bearings due to water contact, and also minimizing drag when the structure is moved in the water.

In the case of a structure to he towed on a road where size is limited by factors such as road size, transport regulations and stability of the structure at speed, folding of the structure may enable a much larger structure to be towed.

W : : h e structure is a foldable boat for example, it may be possible for the bti..: to bv of such a size that it can carry its own towing vehicle when floating or. water.

The foldable structure may be foldable in any configuration depending on requirement?. However it may preferably be folded along a transverse or longitudinal axis since in this case components may be made identical or s:"'.;!ar. Furthermore, folding along a transverse or longitudinal axis may result in minimum external dimensions of the structure.

For structures to he transported on a road the structure may preferably be folded along a longitudinal axis as this may result in a minimum height and v. Kith. However for certain structures where storage is a consideration, it may br preferable to fold the structure along a transverse axis so as to take up minimum ground space.

I; :s generally envisioned that in the case of a foldable boat, the boat would be of a twin hull configuration with port and starboard hulls foldable about a central longitudinal axis of the boat. However other configurations such as a single hull or triple hull configuration may also be possible. The shape of the hulls may be designed for minimum wind resistance when in a towing configuration and for optimum size and shape when unfolded in*o a boat conflgu ration. ;The means for connecting the structural members together may comprise a hinge member whereby the structural members may be folded relative to each other, and the second support means may include sections of the structure on. either side of the hinge element. The hinge element may be a standard type hinge with a hinge pin, or any other suitable mechanism that allows ;s: ructura! me mbers or sections of the structure id be folded relative to each other. For example, it may comprise pivoting links. ;lr. tin- case of a twin hull boat configuration, port and starboard hulls may each be formed with an inner section including a hinge member whereby the hulls are connected together, and an outer section including a fluid displacement or floatation section which supports the boat when in the water. ;T:ie first support means may he connected to sections of the foldable structure on either side of the hinge element by any suitable connecting means whereby sections of the foldable structure are able to move relative to members of the first support means. For example wheels, sliding elements, pivotal links, fluid operated actuators, pulleys and cables, or a combination of these may be suitable. In this way the hinge member may move relative to the first support means as the folding structure is folded, thereby enabling the first support means to be accommodated within the foldable structure when the structure is 1:: the open configuration, and to protrude in part or fully from the foldable structure when in the folded configuration. ;Furthermore the means for connecting of the first support means to the section or sections of the foldable structure may comprise locating means so that the foldable structure is positively located on the first support means when in the folded configuration, and the first support means is securely attached to the foldable structure when in the open configuration. ;With a foldable structure such as a twin hulled boat having built in wheels for enabling the boat to be towed on the road, a portion of the inner section of each hull may be connected to a wheel/main-axle assembly of a first support means by a connecting means such as a sliding linkage, pivotal linkage or combination of a linkage and wheel mechanism whereby the wheels may extend from the hulls when the hulls are folded together into a towing ;^^nfiguration fur towing on a ruaci. and the wheels may fit into wheel welis in tm- hulls when the hulls are opened into a floating configuration for floating on w a'• ■ r. ;The first .support means may comprise one or more wheel/main-axle assemblies for supporting the foldable structure. These may comprise a suspension system such as a torsion suspension system between the wheel axles and the main-axle. Alternatively a leaf spring suspension may be provided with the leaf spring positioned between the wheel axle find the main a>:!e. In this case the wheels may be rotatably supported on stub axles with a pivotal link to the main axle to provide sideways support of the stub axle while allowing relative sprung motion between the stub axle and the main axle. ;The structure may be opened and closed by means of a tension member connected between portions of the foldable structure, and a winch which is able to tension the tension member to fold the sections of the foldable structure to:;* : her, and untension the tension member so that the sections can swing apart under their own weight. However any other device that is able to fully open and close the foldable sections of the structure is possible. For example a hvdraulic actuator may be provided for moving the foldable structure relative to t he first, support means.

The foldable structure may be held in the open and closed configurations by any suitable fixing means. Typically this may include a locking device which locks an opening and closing device, or pins which fit into holes that line up when the foldable portions of the structure are in either the opened or closed conf'igu rations.

In. the case of a wheeled foldable structure that is supported by water displacement in the opened configuration, the arrangement may be such that the Mippor: wheels are positioned with the wheel bearings above the water level supported on the water so that the bearings arc kept ;>s drv as possible. Covers may also be provided on outer surfaces of the structure to cover the v.h< • ! '.•.-•■lis and provide a smooth surface to minimize drag. These covers mav also be sellable so that the wheel wells can be drained of their water, enabling the wheels to dry out when the structure is used for extended periods on water.

The provision of built in wheels on a floating structure, enables the structure to b. brought ashore at any suitable location and towed away without the need for a trailer. This overcomes the requireijient for space on land for storing a trailer v.he:1, the structure is being used.

I:-, the case of a foldable floating structure such as a boat, since the width of the structure is not as limited as that of a conventional fixed shape hull, it may be pn-.-.]ble to make the boat large enough to carry its own towing vehicle. The versatility of the boat is therefore greatly improved, and as well as being suable for general use. the boat may be used for other applications requiring its unique features. Typical applications may be for emergency use such as in i"1"'iied regions where roads are blocked by flooding, for use in outback regions where there are no bridges across rivers, and for general recreation use where i: : - des;r< d to launch and beach the boat at different locations.

As well as having a means such as a tow coupling for connecting the foldable >;ruciure to a towing vehicle, the foldable structure may also be provided with us own built in drive unit to facilitate positioning of the structure on land, or in the case of a floating structure, to facilitate launching and beaching of the structure. The drive unit may comprise, a battery powered electric motor driving one or more wheels and controlled by a switch near the tow coupling.

In the case of a foldable boat, motive power on the water may be by one or more inboard or outboard motors driving either a propeller or water jet unit. Alternatively wind power such as with a sail, or with a wind turbine driving a ^^)r<.tnrough a trar..--:':::.-sion may be used. When a lowing vehicle- or other road vehicle is carried on tin.- boat, the power unit of the vehicle may be used as a source of motive power. Furthermore, other functions of the vehicle may be used. For example, in the case of a car or van, the steering may be adapted to steer the boat, the cab may be used for protection from the weather, the lights may be used for navigation and the windscreen wipers may be used in rainy and heavy weather conditions. In the case of a wind powered turbine propulsion system, this may be adapted to utilize the vehicle transmission system.

Th'- reduced restriction to the width of the foldable boat also enables a wide deck area so that a shelter or structure may be erected or unfolded when the boat is op'-ned up providing a covered living area. The wide deck also provides a large aiva for general recreation.

Aspects of the present invention will now be discussed by way of example only with reference to the accompanying drawings in which: l';:;i:re 1: is a general perspective view of a folding boat according to a possible embodiment of the present invention in a towing configuration behind a towing vehicle, and Figures 2a to 2c: are respective views on a section such as A-A of Fig. 1 showing details of a possible foldable structure according to another possible embodiment of the present invention with the structure in respective folded, half opened and fully opened configurations, and Figures 3a to 3c: arc respective views on a section such as A-A of Fig. 1 showing details of another possible means for folding the foldable structure of Fig. 2 with the structure in respective folded, half opened and fully opened configurations, and ^^igures 4a to 4d: are respective stern and side views of the boat of Fig. 1 in respective folded and opened configurations, and Figure 4e: is a stern view of the boat of Fig. 1 with the hulls in a partially opened configuration showing details of a possible means for folding the hulls, and wheeled means for supporting the hull structure, and Figure 5: i.s a perspective view of another possible embodiment of a folding boat of the present invention in a floating configuration, showing a towing vehicle, mounted on the folding boat.

With, respect to Fig. 1 there is shown a folding boat 1 according to one possible embodiment of the present invention in a towing configuration behind a towing vt-iiu'!e. The folding boat 1 comprises a port hull section 2 and a starboard hull ,-rction 3. foldinglv connected together by a hinge member 4 so as to able to fold about the hinge member 4. The folding boat 1 can be towed on a road by a towing vehicle 5 which is connected to the folding boat 1 by a coupling generally indicated by arrow 6.

Support for the folding boat 1 is provided by a wheel support unit generally indicated by arrow 7. In the figure, two wheel support units are shown, however the following description will consider only one unit for simplicity. The wheel support unit 7 comprises wheels 8 attached to a main axle 9 by means of a torsion suspension unit 10. Wheel wells 11 are provided in the bottoms of the hulls 2, 3 adjacent to the wheels S for accommodating the wheels S when the boat is in an open configuration (see Figure 4c).

The folding boat. 1 is powered on the water by propulsion units generally indicated by arrow 11'. The propulsion units 11' may comprise two water jet units each having an intake 12 and a steerable discharge nozzle 13 fitted to each hull 2, 3. ^^•'■gures 2a to 2c are respective views on a section such as A-A of Fig.1 showing ills of a possible foldable structure according to the present invention l'' .•".'•.'•ally indicated by arrow 101. The foldable structure 101 comprises left and r:_'h.: folding sections 102, 103 shown in respective folded, half opened and fully <>: "::ed configurations. The foldable structure 101 is supported in the folded c- nfiguration by rollers 150 which are rotatably supported on axles fixed to r-. --p.-ctive left and right folding sections 102, 103 and which rest upon an upper surface of the main axle 109. The foldable structure 101 is further supported m moving sideways on the axle 109 by lock pin rollers 152 acting as locating .ms, which are fixedly connected to respective sections 102 and 103 and winch are able to slide in a slot 154 formed in the main axle 109. In the folded cr,minion, the lock pin rollers 152 are in contact with outer end portions of the slots 154 so that structure 101 is prevented from moving sideways.

The main axle 109 is supported on wheels 108 by means of the leaf spring pension unit 110 fitted to a spring support 110a which is welded perpendicularly and horizontally across the ends of the main axle 109. The wheels 10S are rotatably mounted on stub axles lOSa and are further connected to the main axle 109 by a pivotal link 109a to provide sideways support of the stub axles 108a while allowing relative sprung motion between the stub axle lOSa and the main axle 109.

A central guide 156 is welded to the main axle 109 so as to lie in a vertical direction. The central guide 156 is formed as a channel section with upper and lower ends flared to guide the entry of a hinge roller 15S mounted on a pin of the hinge 104.

Figure 2b shows the foldable structure 101 in a half opened configuration. In this configuration the lock pin rollers 152 are separated from the ends of the 154. and sideways movement of the structure is resisted hv the hin^e roller 15s which moves in the central guide 156.

Figure 2c show; the foldable structure 101 in a fully opened configuration. In this configuration the main axle 109 and wheels 10S are supported by the left and right folding sections 102, 103 via the lock pins rollers 152 which are located at inner end portions of the slots 154. The wheels 10S are thus accommodated v.t.li in the sections 102, 103 in an unloaded condition so that if necessary they mav be easily removed. Furthermore if the foldable structure 101 is a floating s'-:ucti:re. the wheels 10S may be positioned so as to be above water level thereby minimizing deterioration of the wheels and bearings due to water contact, and also minimizing drag if the structure is to be moved in the water.

When the structure is opened on the land, at a certain stage of the opening operation when the outer lower edges of the sections 102, 103 come in contact with the ground, the movement of the structures 102, 103 relative to the ground may be facilitated by temporary support wheels 155 fitted to suitable outer edge pen ions of the sections 102, 103. These temporary support wheels 155 are pn.-i! loned so that in the fully opened configuration they are no longer loaded.

Figures 3a to 3c are respective views on a section such as A-A of Fig. 1 showing details of another possible means for folding the foldable structure 101 of Fig. 2 with the structure 101 in respective folded, half opened and fully opened configurations. Components such as the wheel and main axle similar to those of Figs. 2a to 2c are given the same numerals for identification, and description is omitted. In this embodiment the folding sections 102, 103 are supported by links 160 which are pivotally connected between the sections 102, 103 and the main axle 109.

The location and dimensions of the links 160 is such that at a certain stage of the opening operation as shown in Fig. 3b, the links 160 are in such a position ^pk;u with further opening of the structure 101 they may swing either upwards or downwards. If the links 160 are swung upwards from this position, the main, axle 109 and wheel assembly may be accommodated deep within the sections 102, 103 as shown by the full outline drawing in Fig. 3c. If the links 160 swing downwards from the condition of Figure 3b then the main axle 109 and wheel assemble will be accommodated in a lower position within the sections 102. 103 as shown by the dotted outline in Figure 3c.

In the case of a floating structure 101, the main axle 109 assembly will naturally drop down due to gravity as the structure 101 is sup-ported by floatation of the sections 102, 103. This drop due to gravity may also be achieved in a land based structure by having the sections 102, 103 supported at their corners by wheels such as the wheels 155 shown in Figure 2. To cause the mam axle' 109 assembly to move upwards from the condition shown in Figure 3b. a suitable device such as a cantilevered spring may be attached to the hinge element 104 so as to catch on the main axle 109 as the hinge element 104 moves relative to main axle 109. thereby moving the main axle 109 a predetermined distance together with the hinge element 104 before releasing from the main axle 109.

The use of link elements 160 instead of main rollers 150 eliminates the need for a central guide 156 and also may overcome problems caused by foreign matter accumulating on the upper surface of the main axle 109 and tending to prevent smooth motion of the main rollers 150. Furthermore with suitable design, the main axle 109 may be raised higher within the sections 102. 103 than would be possible with the roller system of Fig. 2.

Although in the arrangement of Figs. 3a to 3c the link 160 is positioned and sized so as to enable the main axle 109 to be positioned higher up in the sections 102. 103 when the foldable structure 101 is in the open configuration, this ^^e<:i:irt :r.er.t may not be necessary and tin- link may be sized and positioned so that the pivotal connection to the sections 102, 1013 is always on either an upper side or lower side of the main axle 109 during the opening and closing operation.

A means for folding the foldable structure 101 may include a hydraulic actuator connected between the main axle 109 and the hinge pin 104 so that by extension and retraction of the actuator, the hinge 104 may be moved relative to the main axle 109 thereby opening and closing the structure 101. Alternatively cables may be connected between the sections 102, 103 and tensioned and untensioned by means of an opening device comprising a winch and cable system. One possible arrangement is given in the following description of a foldable structure in the form of the boat 1 of Fig. 1.

Figures 4a to 4d show configurations with the boat 1 of Fig. 1 in the open and cloM'd conditions. Figures 4a and 4b show the boat 1 in the closed condition for road transport. In this configuration, the port and starboard hulls 2 and 3 may be held together by a suitable means such as bolts or straps ( not shown). A coupling 6 comprises a tow coupling 20 removably attached by a pin 21 to a central section of a deck portion 24 of the boat 1.

Figure 4e shows a condition of the boat 1 with the hulls 2 and 3 partially open. The hulls 2 and 3 are opened using an opening device generally indicated by arrow 30. The opening device 30 comprises a removable winch 3.1 connected to the starboard hull 3, with a connecting rod or cable 32 connected between the removable winch 31 and a point 33 on the port hull 2. The hulls 2 and 3 are supported on the main axle 9 by means of pins 34 and 35 which slide in a track 3(i in the main axle 9.

To open the hulls 2 and 3 to a floating configuration, the winch 31 is rotated so as to increase the length of the cable 32, thereby allowing the hulls 2 and 3 to

Claims (1)

1. ,wer to a condition where internai faces 3 . and 3^ of the hulls 2 and 3 respectively abut against each other, and deck portions 39. 40 of the hulls 2 and 3 respectively lie substantially in the same plane. The hulls may be held in the open configuration by suitable attaching means such as bolts (not shown) fitted between the internal faces 37 and 38 of the hulls 2 and 3. In the open configuration, as shown in Figure 4c, the wheels 8 are retracted into the wheel wells 11 of the hulls 2 and 3 so as to minimize drag when the boast is moving in water. In this condition wheel bearings (not shown) are positioned above the water level of the hulls to keep them dry. Figure 5 shows the boat 1 of figure 1 with the towing vehicle 5 mounted in position. In this configuration the cab 230 of the towing vehicle 5 may be used for protection from the weather, the lights 231 may be used for navigation, the windscreen wipers 232 may be used to clear the windscreen of rain and spray, the steering wheel 233 may be used for steering the propulsion units 11'. The boat and towing vehicle assembly can therefore be driven in a similar manner to driving the towing vehicle 5 on land. Drive from the vehicle 5 transmission may also be connected to a gearbox unit (not shown) for driving the propulsion units 11. Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof as defined in the appended claims. - is - WHAT I CLAIM IS: 1. A foldable structure comprising; at least two structural members pivotally connected together so as to be foldable relative to each other about a longitudinal axis of said structure, between an open configuration and a closed configuration of said structure, first support means comprising at least two support members disposed in substantially fixed spaced apart relation to each other, for movably supporting said structure when said structure is in said folded configuration, second support means for supporting said structure when said structure is in said open configuration and, respective connecting means for connecting each of said structural members to said first support means, with said pivotal connection disposed therebetween, the arrangement and construction being such that said first support means is accommodated within said structure when said structure is in said open configuration, and protrudes from said structure when said structure is in said folded configuration. I. A foldable structure as claimed in claim 1 wherein said structural members comprise two hull sections, said first support means comprises a wheel assembly with at least two wheels acting as said two support members with axes of rotation substantially perpendicular to said longitudinal axis, and said second support means comprises floatable sections of said hull sections whereby said structure can be floatingly supported on water in said open configuration with said wheel assembly retracted into said structure. -1 9- A foldable .structure as claimed in claim 2 wherein said structure is in the form of a boat, said hull sections being pivotally connected along a longitudinal central axis of said boat, and said wheel assembly comprises a transverse beam member with one or more wheels rotatably supported at each end, each of said hull sections being supported on said wheel assembly by said respective connecting means, whereby said hull sections may move relative to said wheel assembly as said hull sections are folded and unfolded, and said wheel assembly can be supported by said boat when said hull sections are floating in an open configuration. A foldable structure in the form of a boat as claimed in claim 3, further comprising means whereby said boat can be towed behind a vehicle in said folded condition, and said hull sections are adapted to be able to support said towing vehicle when unfolded to said open condition and floating on water. A foldable structure as claimed in any one of claims 1 to 4, wherein said connecting means comprises means for positively locating said foldable structure with respect to said first support means when said structure is in said folded configuration, and for securely attaching said first support means to said foldable structure when said structure is in said open configuration. A foldable structure as claimed in any one of claims 1 to 5, wherein said structure further comprises means for opening and closing said structure between said folded configuration and said open configuration. I. *) <. \ •••-, /« 7 C sJ 3 J v / A foldable structure as claimed in claim 6, wherein said opening/closing means comprises a tension member connected between portions of said foldable structure, and a winch which is able to tension said tension member to fold said structural members of said foldable structure together, and to untension said tension member so that said structural members can swing apart under their own weight. 8. A foldable structure as claimed in claim 6, wherein said opening/closing means comprises an actuator means provided between said first support means and said structural members. 9. A foldable structure substantially as described herein with reference to the accompanying drawings. ' Vl > - v i 'us he'/ their /its AffnmaM JAMES ^ YYF( |,fj^ Per 1 FIGURE 1 DENIS LEE STEWART by his Attorneys JAMES & WELLS 101 102 DENIS LEE STEWART by his Attorneys .^2 C JAMES & WELLS FIGURE 2 101 102 FIG.3a FIG.3c 108 FIGURE 3 DENIS LEE STEWART by his Attorneys -'"Y / £ L JAMES & WELLS 233 FIGURE 5 DENIS LEE STEWART by his Attorneys /f U JAMES & WELLS