GB2267468A - Foldable trailer - Google Patents

Abstract

A trailer (10) has a main base part (11), a pair of wheels (90A, B) with suspension means (50-59) permitting folding of the wheels under the main base part (11). Side (13, 15) and end (25, 27) wall parts have hinging (17, 19; 29, 31) permitting their folding to substantially parallel relation with said main base part (11) and substantially within confines of the main base part (11) viewed in plan. Fore and aft base extension parts (21, 23) carry the end wall parts (25, 27) and are also foldable onto the main base part (11) along with side extension wall parts (33, 35) hinged to the main side wall parts (13, 15). Extensible and retractable tow hitch provisions (61) swivel to stow below and within the width of the main base part (11). Number plate and lights carrier means (80) is also extensible and retractable below the main base part (11). <IMAGE>

Description

WHEELED TRAILERS This invention relates to wheeled trailers for towing behind motor vehicles, usually motor cars, particularly to wheeled trailers that can be folded up compactly when not in use.

We believe there is a need or at least a good market for a wheeled trailer that can be folded compactly to aid convenience of storage and/or transport without being towed; and we are unaware of any satisfactory commercial product of that nature. Accordingly, it is a general object of this invention to provide such a trailer, According to one aspect of this invention there is provided a wheeled trailer for towing by a motor vehicle, the trailer being foldable when not required to be towed, the trailer comprising a main base part with a pair of wheels associated therewith, one at each side of the main base part with their rotation axes aligned (for towing), by way of suspension means permitting folding of the wheels to extend under the main base part from each said side with their rotation axes then substantially perpendicular to the main base part; and other parts af the eai2r, whether sides and ends of an open topped hox structure and/or fore and/or aft extensions of the base, being hinged so as to fold over substantially parallel to, preferably down onto, and substantially within the confines of the plan area of the main base part Preferably, side wall parts hinged to sides of the main base part fold directly onto the main base part.

Preferably, end wall parts of the trailer are hinging associated with additional base parts (as said fore and aft extensions of the base) themselves associated with the main base part by hinging that may be of an extensible nature and permits folding of the additional base parts over the main base part, preferably onto folded side wall parts of the trailer. Preferably, further side wall parts for said additional base parts, are hinged to the first mentioned side wall parts, advantageously for folding back over the latter as folded onto the main base part, and advantageously below folding of the additional base parts themselves.

Suitable hinging between side wall parts and further side wall parts can comprise flexible, preferably resilient, material (such as rubber) extending between locating pins. Suitable hinging between side wall parts and the main base part can comprise pivot bars extending and extensible out of the main base part to side wall pivots, preferably biassed against extension that permits pivoting, then advantageously on guide and spring mounting provisions. Suitable hinging between additional base parts and the main base part can be of flexible web type, or be of extensible link type, say comprising slotted bars and retaining studs on the edges of the main and additional base parts, the slotting allowing separation sufficient for the aforesaid preferred and advantageous folding. Particular advantage can arise from providing that additional base parts have make a positive connection with the main base part in erecting the trailer, say by way of latches that need specific release for folding the trailer, for which spring loaded sliders and headed retainers are suitable.

It is preferred that side wall parts and further side wall parts have connecting stiffeners between them, say of retractable bolt type at or close to their top edges and with quick release swivelling tension tabs at their ends beyond the further side wall parts to hold against separation; and/or formations that interlocate edge-to-edge, say by holes and hole-entrant bellings or neck formations that are also preferred between wall parts and base parts.

Side wall parts of the trailer could fold across up to half the width of the main base part, but additional base parts are limited by their folding requirement to extend no more than half the other dimension of the main base part, and that other dimension will usually be smaller than the width. For maximum side wall part heights, and matching erected heights of end wall parts therewith, the end wall parts could be of two-part formation in their height, whether hinged together or the upper slidable on the lower (which may be of substantially the same extent as the associated said additional base part). The alternative, as will be described, is for all wall parts to be of one height, which can be the maximum for one piece end wall parts and match the extent of the additional base parts.

It will be appreciated that a basic structure having a main base part with directly associated trailer side wall parts folding onto it, and wheels folding under it from each side, is particularly easy to erect and to fold, particularly where all other trailer side wall or base extension parts fold over onto the side wall parts directly associated with the main base part.

A trailer with erected dimensions or three feet wide (about one metre), four feet long (abut 1.3 metres) and sides/ends eighteen inches (about half metre) high can fold down into a volume of about three feet (one metre) by two feet (two-thirds metre as main base part width and other extent, respectively) by one foot (one third metre as thickness of wheels and mountings plus base and folded side/end wall/base extension parts). Such a folded unit is readily stowed almost anywhere, and should even be portable in most vehicle boots or trunks when not erected.

As well as aspects of invention arising from folding of side wall parts and from doing so in conjllnction with additional base parts preferably successively to one side of a main base part, further aspects of invention reside in basic folding of wheels relative to a main base part of a trailer and latching them in folded or extended state, and in suspension units preferably involved in wheel mounting relative to the main base part of a trailer.

A suitable suspension unit of this invention has a compact structure resulting from comprising an arm that is medially pivoted in a frame and extends to a rotary wheel bearing, say a stub-axle extending therefrom, at one end free of the frame and bears on a frame mounted resilient shock absorbing unit between its pivot and its wheel bearing, with its other end within the frame between a first resilient stop engaged only at reduced or zero wheel loadings and a second resilient stop engaged should the shock absorbing unit fail. Engagement of the arm with the first resilient stop represents a stowing state of the arm and accompanying wheel, i.e. where the frame is pivotable from a position where the arm extends inclined downwardly to the wheel to a position where the arm extends over and generally parallel with the plane of the main base part of the trailer. Preferably, the frame latches securely relative to the main base part in either of those positions.

One suitable latching provision comprises at least one spring-loaded catch for each suspension frame, say extending sideways into a cheek of a pivot bracket or shoe, or directly into underfloor stiffening of the main base part. Positive release provisions are readily made easily accessible in both of erected and folded states of the trailer. Such catches may have operative latch members parallel with a pivot pin of the related suspension frame conveniently located at an inboard corner of such frame. It is particularly preferred for there to be two catches operative in the erected state, conveniently going from the suspension unit into each of flanking cheeks or underfloor stiffening, and advantageously aligned for simple release by squeezing finger holds together against spring biasses for catch bolts; though a single finger or thumb push release is generally enough (feasibly one of the two catches from a different latch hole) for holding and releasing the retracted state.

Another preference is for erected trailer wheels to be at a small angle to the vertical, particularly with the wheel tops more outward, thus aiding access, say for release of catches for suspension units.

One suitable mudguard and mounting thereof is associated with said pivotally mounted wheel suspension frame or arm or stub axle supported thereby, preferably to move up and down with the wheel. It is feasible to prevent rocking of the mudguards by use of a pantograph support system having a mudguard support strut that is pivoted to said arm adjacent, conveniently above, the wheel bearing, and a guide strut pivoted to the mudguard support strut and to said suspension frame in parallel relation with said suspension arm In any event, the arrangement is such that the mudguard will tuck within the overall confines of the main base part in the stowing position, and will "ride" up and down with the wheel in the extended and operative position of the frarre, suspension arm and wheel. A convenient mudguard ntount that allows some movement with the wheel, in fact enough to avoid fouling in use but with actually varying clearance (rather than maintaining constant clearance as for a true pantograph system), utilises a linkage to the suspension unit casing and to the trailing suspended wheel carrying arm.

Further aspects of this invention concern tow-bar and tow-hitch provisions, and number plate and or trailer light mounting provisions.

A preferred tow-bar is of telescopic type with an outer elongate member into and along which an inner member is slidable between retracted and extended positions, and the outer member is pivotable from a forward extending direction to a sideways extending direction below the main base part of the trailer, say in and slidable lengthwise relative to a turn-saddle bracket secured below the main base art. A preferred tow-hitch is rotatable through 90" from an operative to an inoperative position in which it can pass below the main base part of the trailer, say on the free end of the inner member of the preferred tow-bar, or with such inner member.

The overall length of a preferred telescopic towbar, when retracted, and tow-hitch should not exceed the width of the main base part, but can advantageously be as near the forward end of the main base part as practicable, say with a flank of a preferred turn-saddle bracket then substantially flush with the front edge of the main base part, or close to being so, and medial of the outer member of the tow-bar. For erection, pulling the tow-bar outer through the turn-saddle bracket and turning it therein is preferably succeeded by pushing it back through and into a docking bracket or channel for securement therein, whether by a pin that could afterwards serve to secure the inner member of the tow - bar in its retracted state, cr by other provisions that could be of a latching type.

In a particular preferred arrangement, a said docking bracket for the outer part of a telescopic towbar has an elongate U-section shape with spring loaded catch means at its inner end. Suitable catches, preferably two operative each through opposite sides, respectively, of the docking bracket, have pullers to withdraw catch members against spring bias, and rests for the pullers, conveniently after rotation of same, with the springs compressed. Release of such catches will serve to locate the docked outer member of the tow-bar.

however, that may be only a first location, i.e. there may be a further conveniently screw thread operated location means. This preferred docking bracket may carry (below it in the erected and operative state of the trailer) a mount for such further location means, or at least afford a swivel mount for the turn-saddle bracket then extending therefrom in front of the docking bracket below an overhang of this mount relative to the docking bracket as such.

A preferred number plate and brake light carrier is mounted using a slide that is securable in extended or retracted positions, advantageously both, further preferably with some degree of compliance at least for accommodating to contacting tyres of retracted wheels. 2.

single central slide could, when retracted, occupy the above-mentioned docking bracket or channel. however, it is preferred to have two slides spaced to each side of such docking bracket or channel, which can also have the advantage that supporting or otherwise related mounting provisions on the underside of the main base part can be made and located for extra stiffening and strengthening of the main base part. A particular preferred number plate and rear lights provision with two slides and a central reinforcement/stiffening of the main base part by way of light-weight spaced members with plural crossbracing has its two slide holders equipped with two clamps, respectively, that are operable for both of retracted and extended states, and (when extended) will permit the whole trailer (then still with its sides and any additional base parts folded onto the top of the main base part) to be turned over onto its erected wheels by pivoting over the extended number plate and rear lights unit.

A particular preferred number plate and rear lights provision is itself of a folding nature in terms of a basic carrier part fixed to its extension/retraction slide means and an actual number plate/lights mounting part hinged to the basic carrier part and rotatable upwards for in-use securement to the back wall panel of the fully erected trailer. When not so secured and turned down onto the basic carrier part the mounting part will conceal and protect the rear lights /number plate.

However, a higher positional requirement (than under the trailer base) can be satisfied.

In ger.eral, maIn be part stiffening and strengthening provisions can extend widthwise between and contributing to, even largely if not wholly constituting, mounting provisions for the suspension units; and can extend lengthwise fore and aft for tow-bar and numberplate etc mounting/retraction provisions.

Specific implementation will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figures 1, 2 and 3 are side, end and plan views of an erected trailer; Figures 4, 5 and 6 are side, end and plan views of the same trailer in the folded statue; Figures 7,B and 8 indicate wall panel and base outline sections, respectively, and Figure BA shows base part hinging; Figure 9 is a side view of wall panels with further details in Figures 9S,B; Figures 10,B show details of hinging between side wall and main base parts; Figure 11 is a side view of a preferred wheel suspension system; Figures 12A,B are plan and side views of a suspension pivot bracket or shoe; Figure 13 is a side view of a pantograph type mudguard mounting system; Figure 14 shows alternative main base part strengthening; Figure 15 is a bottom plan view of another embodiment of foldable trailer in its fully folded state; Figure 16 is a similar view but with number plate and rear light unit extended, also to-bar/htch extended and docked; Figure 17 is a side view of the trailer as in Figure 16 but turned over onto its wheels and ready for its sides and fore/aft base parts to be unfolded, but already hitched up to a towing vehicle; and Figures 15A,B; l6ArE,c; and 17A, show various specific details of the Figure 15 embodiment.

In the drawings, referring first to Figures l to 3, a trailer erected for use is referenced 10, and comprises a main base part 11 with main side wall parts 13 and 15 that are hinged (17 and 19) thereto at mutual edges. Fore and aft base extension Darts 21 and 23 have end wall parts 25 and 27 hinged (29,31) thereto at mutual edges, and further have related side wall extension parts 33A,B and 35A,B that are hinged (3 > A,3 and 39A,B) te ends of the main sides wall parts 13 and 15.

Turning to Figures 4 to 6, the matn si.de wall parts 13,15 can fold down over the main base part 11 and are both shown doing so directly onto the main base pat 11.

In that folded down state of the main side wall parts 13 and 15, the side wall extension parts 33 and 35 fold back onto the main side wall parts 13 and 15. The base extension parts 21 and 23 are on flexible web or extending link hinges (see slotted bar 1 and headed studs 43A,B in Figure 8A)r so that those parts 21 and 23 can fold down on top of the side wall extension parts 33 and 35, then with the end wall parts 25 and 27 folded down on top of the base extension parts 21 and 23. All such folding is shown as being onto the top side of the main base part 11.

Side wall parts can be made from suitable aluminium alloy sheet, preferably ribbed for strength (not shown).

They are indicated in Figures 7A,B extending between ends 45 of channel-section (and preferably smooth), with upper and lower returns 46A,B (with edges further turned back) and central indent 47, all formed within the channelsection of the ends 45.

Base parts can also be formed from suitable metal sheet having sides 48A,B returned (with edges further turned back as may be preferred), also normally between channel-section end components (not shown) ; and having stiffening and strengthening members at its underside, see inverted top-hat secti.on members shown dashed in Figure 3 across the width of the main base part and extending fore and aft therefrom.

Hinging between side wall parts is indicated in Figure 9A as being by a flexible web extending between securement pins that will be suitably held in receivers on the side wall parts (not shown) Similar hinging is suitable for end wall parts 25,27 to the fore and aft base extensions.

Stiffening and securement bolts are shown in Figure 9 at upper locations of the side wall parts complete with tensioning tabs at their ends to draw and hold the wall parts together as shown, and simply swivel into alianment with the bolts for easy release to fold the trailer. Also, location formations as cooperating plain holes and entrant belled or necked holes, see Figure 9B, can serve between wall part edges, whether to other wall parts or to base parts Hinging between side wall parts 13,15 and the main base part 11 is indicated at 49 in Figures lOA,B by way of pivot bridges 49P in bottom returns of the side wall parts for pivot bars 49B extending from a guide ring 49R on a guide rod 49G in side returns of the main base part 11, and extensible therefrom against bias from a spring 49S, conveniently of polyurethane. A wear pad 49W is shown on the main base part, and may be of Nylotron.

Reverting to Figures 1 to 3, the main base part 11 further has, at each of its sides and to its underside, suspension frames 50A,B of generally U-plate construction for trailing suspension arms 52A,8 pivoted medially thereto at 54A,B and having wheel bearings or stub-axle mounts 55A,B at their free ends. The frames 50A,B are pivotally or hingedly mounted to the main base part 11 se as to be able to adopt the alternative retracted positions indicated in Figures 4 to 6, and can be securely latched in either of extended or retracted states.

Figure 11 shows outer plate 50X of a said suspension frame with trailing suspension arm 52 medially pivoted by pin 54P in bearings 53 and passing through each side plate of the frame. The frame carries a shock absorbing block 51 engaged by the arm 52 between its pivot 54 and its mounting hole 55 for a stub axle (not shown). The block 51 is of suitable resilient rubber type material, as may be a first stop 56 engaged by the arm 52 inboard of its pivot 54 only for reduced or zero load, and a second stop 57 that will be operatively engaged only at severe overload or failure of the basic shock absorber block 51.

Xt will be appreciated that the whole of the suspension unit frame 50 will hinge or pivot with the arm 52 going into the plane of Figure 11, actually about its upper and inner corner, i.e. of its inner side plate 501.

Figures l1A1B show inner side plate SOT with tubes S8R,B and 59 welded thereto, the former for a pivot or hinge pin and the latter for a spring loaded catch (not shown) extending through either or both its ends and operable by a side peg going through slots 59S in the tube 59. The hinge or pivot pin of the tubes 58A,B can go into either of cheeks of a trunnion bracket for the suspension frame concerned or directly into such as spaced C-section stiffeners of the main base part at its UliUefr'Si e, Figures 12A,B show details of a practical trunnion bracket 70 as a shoe for pivoting a suspension bracket, and shown having a hinge or pivot pin passage tube 71 welded to its base web as well as registering holes 72ASB in its sides. In addition, there are holes 73A,B for receiving and latching bolts or catches from the tube S9 of Figures llA,B in the extended and retracted states of the suspension unit frame, arm and wheel on its stub axle.

Also, the main base part 11 carries at its underside a turn-saddle bracket 60 for an outer member 61 of a towbar provision 62 whose inner member 63 is slidable into and out of the outer member 61. The outer member 61 is also slidable lengthwise in the turn-saddle bracket 60, and there is a docking bracket 64 secured to the main base part 11, actually an inverted top-hat section channel, that will receive and locate the outer member 61 when slid through the turn-saddle bracket 60. In the retracted state of the members 61 and 63, but with the outer member 61 slid out of the docking bracket 64, they can be first swung in the turn-saddle bracket 60 then slid back through the turn-saddle bracket to allow them to come into a position extending across the width of the main base part 11.

A tow-hitch 65 is indicated as capable of being turned through 9OC about the axis of the inner tow-bar member 63 so as also to stow under the main base part 11 with the combined length of the retracted inner and outer members 61,63 and the tow hitch 65 within the width of the main base part 11 and at or close to flush with the forward end thereof. It can be preferable for the towhitch 65 to be rigid with the inner member 63 and for the inner member 63 to be rotated, rather than the tow-hitch twist on the inner member 63. Indeed, a bayonet type of location for the inner member 63 in the outer member 61, say between two internal plates of the latter, could feasibly also assist in lengthwise security of the towbar (for towing purposes), perhaps instead of or additional t latches or pin provisions (not shown but readily provided) to that end.

Number plate and brake light provIsIons are also shown at 80 on a panel mounted to a central slide tube 81 so as to be retractable through brackets or guides 82arm under the main base part 11 from an extended position below the end of aft base extension part 23 to be within the confines of the main base part 11. Compliance in upper mounting of the panel 80 to the slide tube 81 can aid such retracted location and permit some degree of engaging contact with tyres of the trailer wheels 90A,B.

Suitable mudguard (90) provisions can be by way of mounting, say simply by a V-frame to the suspension arm or to a stub axle and will move with the wheel and suspension arm. Alternatively, Figure 13 shows a pantograph support system with a mudguard support strut 91 shown extending vertically from a pivot 92 to the suspension arm directly above the wheel bearing or stub axle mount, and a guide strut 93 extending parallel with the suspension arm between pivots 94 to the support strut and 95 to the suspension frame directly above the suspension arm pivot in the suspension frame. Such a parallelogram type support linkage will assure against rocking of the mudguard, but still move up and down with the wheel and not present any problems for stowage under the main base part when the trailer is folded up.

Figure 14 shows alternative width-wise strengthening and stiffening of the main base part 11, by way of spaced C-section (or side-on mounted channel-section) members 96A,B between which the suspension frames can be hinged and latched directly, i.e. without requiring trunnion brackets or shoes. Such spaced C-section members can, of course, be interconnected beyond the suspension units, say by top plates to give a stiff and strong box-section.

Fore and aft stiffening and strengthening members would still extend from the spaced C-section members, say centrally and involved in mounting the docking bracket and turn-saddle for the tow-bar (as shown in Figure 3) and spaced (not shown) carrying preferred spaced guides and slides for the number-plate and lights panel.

In Figure 15, main base part 111 has suspension units 150A,B pivoted between lightweight reinforcing/ stiffening beam sides 196A,B cross-braced at 198A,B,C (as well as at ends). Middle cross-brace 198B extends from at least partly over docking bracket 164, actually from ancillary mount 174 shown extending forwardly beyond the docking tunnel of docking bracket 164 and carrying a swivel 174S for tow-bar turn-saddle bracket 160 in front of the docking bracket tunnel. The docking bracket 164 has, towards its rearward end, spring-loaded catches 175A,E to give first location for the outer member 161 of the tow-bar through sides of the docking bracket 164 For the catches 175A,B, round-section catch bolts 176 are -spring-loaded (176S between thrust washers 176W in housing 175H) against being pulled back by pullers 177 and rotatable for the pullers 177 to engage or disengage rests 178 that serve in holding their retracted states prior to erection of the trailer, specifically turning, extension and docking of the tow-bar outer 161.

Retracted and latched states of the catches 175 are shown in detail views of figures 15A an 16A. It will be appreciated that the outer member 161 of the tow-bar will have holes for latching engagement by the catches 175, see further anchorage 179 in Figure 16A, The mount 174 also has a clamping provision comprised of a screw 173 that operates relative to a shoe or seating on or in the tow-bar outer 161 for main or second securement of the tow-bar in its turned and docked state (Figure 15). The swivel pin 174S can usefully serve as a stop to prevent the tow-bar outer being pulled completely out of the turn-saddle bracket 160 once assembled thereto.

It will be noted that the tow hitch 165 is shown in Figure 15 as rotated less than 90-degrees in its stowed state, it being only necessary to be within the thickness of the tyred wheel, and not fouling same. Preferred spaced plates with rearmost thereof apertured for a cross pin of the tow-bar Inner, and serving as a stop location fox the tow-bar inner when extended, will have such aperture appropriately angled. Figures 15 and 16 also show a stop bracket 162S for the tow-bar inner or its hitch so as to hold the tow-bar retracted when disengaged from the docking bracket 164 and turned for stowage within the confines of the main base part 111.

Such stowage is further held firm by engagement of the outer towbar part 161 at free ends of support bars 181A,B for rear lights/number plate unit 180, which bars 181A,B are shown slidable in guide brackets 182A,B each having clamps (183A,B and 184A,B) for fixing the support bars in either or both of their extended or retracted states. Such free ends of the support bars 181A,B could be fitted with anti-wear and/or cushioning pads, say as press-fit inserts (not shown), The rear light/number plate unit 180 is, in this case, of two part form, see cross-piece 185 fixed to the sup hinged thereto at 187 for folding down at retraction and stowage, but unfolding up for exposing the lights/plate (see lamp lens 180L) when extended and in use.

Securement in either of extended and retracted positions is shown by way of captive band or other coupler 188 and hooks 189R on the crosspiece 185 and 189E on the rear erected trailer wall part, preferably provided at each end of the carrier 186. It will be appreciated that such a hinged two-part lights/number plate provision not only allows satisfaction of minimum or otherwise specified height requirements in use, but also affords protection in the stowed state.

In fact, the extensible rear lights/number plate provision just described will allow the whale trailer with such provision and its tow-bar extended and docked/ clamped out, but still with its walls/base extensions folded up (in fact, lying on same for wheel, tow-bar and lights/plate extension and securement), to be turned over about its lights/plate provision and into the position shown in Figure 17, i.e. ready for erection of its walls and extension of its base.

Figure 17A gives outline diagrammatic indication of preferred location between the main base part l.11 and the additional base parts, see 121. Headed studs 210, one at each side of end edges of the main base part (matlng with the additional base part) and one shown side-on, are engaged by spring loaded apertured plates 212 within end edges of the additional base part and shown end-on.

Engagement can be a simple matter of pushing the additional base part 121 against the main base part 111 (after folding the former out of its stowed state), i.e.

as a snap-f it. For stowing, disengagement is then by pushing in the protruding part 214 and pulling the additional base part away within the freedom allowed by its hinging.

Reverting to the suspension units 150, indicated complete with trailing arms and wheels, Figure 16C shows pivot position 159 and catch bolt position 158E for the erected state, also catch bolt position 158R for the retracted position. For preference, there will actually be two aligned catch bolt provisions 158 with both their bolts spring biassed outwardly and capable of release by squeezing their pull extensions (not shown) together, However only one of those catch bolts needs to engage (at 158R) in the stowed state, and can readily be depressed to release by a finger or thumb. Figure 16B indicates a particularly economical provision made from a single sheet of steel rolled over at each end or side to present pivot pin accommodation 159A and accommodation for catch bolts at 158A and bias spring or springs, with catch bolt pull extensions protruding through slots 1585.

Claims (16)

1. A wheeled trailer for towing by a motor vehicle, the trailer being foldable when not required to be towed, the trailer (10) comprising a main base part (it;111) with a pair of wheels (90A,B) associated therewith, one at each side of the main base part (11;111) with their rotation axes aligned (for towing), by way of suspension means (50-59;150) permitting folding of the wheels (90A,B) to extend under the main base part (11;111) from each said side with their rotation axes then substantially perpendicular to the main base part (11;111); and wherein side (13,15) and end (25,27) wall parts of an erected open topped box structure have hinging (17,19;29,31) permitting their folding to substantially parallel relation with said main base part (11;111) and substantially within confines of the main base part (11;111) viewed in plan.

2. A wheeled trailer according to claim 1, wherein an extension base part (21 or 23) carrying one said end wall part (25 or 27) is hinged (41,43) to the nain base part (11;111) also to fold to substantially parallel relation with said main base part (11;111) and substantially within confines of the main base part (11;111) viewed in plan.

3. A wheeled trailer according to claim 1, wherein fore (21) and aft (23) extension base parts each carrying a different respective one of the end wall parts (27,25) are hinged (41,43) to the main base part (11;111) both to fold to fold to substantially parallel relation with said main base part (11;111) and substantially within confines of the main base part (11;111) viewed in plan.

4. A wheeled trailer according to claim 2 or claim 3, wherein the or each said extension base part (21,23) will fold over said side wall parts (13,15) then folded against the top of the main base part (11;111)

5. A wheeled trailer according to claim 2, 3 or 4, wherein side extension wall parts (33,35) to extend along the or each said extension base part (21,23) are hinged to said side wall parts (13,15) to fold over the latter (13,15).

6. A wheeled trailer according to claim 4, wherein the side wall parts (13,15) have slidable upper elongate stiffening and securement bolts (Fig 9) for extension to secure the side extension wall parts (33,35) when erected.

7. A wheeled trailer according to claim 6, wherein said bolts (Fig 9) further serve to extend through said end wall parts (25,27) and secure same in erected state of the trailer (10).

8. A wheeled trailer according to any preceding claim, wherein each of the wheel suspension means (50-59; 150) comprises a frame unit (50,150) carrying a pivotally (54A,B) mounted trailing arm (52S,B) extending to a wheel mount (55A,B) and a shock absorbing block (51), each said frame unit (50,150) itself being pivotal (58A,B) relative to the main base part (11;111) for folding below the main base part (11;111) together with the wheels (90A,3) carried thereby and having releasable latching means (59,59S;158) for securing relative to the main base part (11;111) in either of extended and folded positions of the suspension means (50-59;150).

9. A wheeled trailer according to claim 8, wherein the suspension frame units (50;150) are pivoted directly between sides (196A,B) of stiffening beam provision for the main base part (11;111).

10. A wheeled trailer according to any preceding claim, wherein the main base part (11;111) has at its underside both a turn-saddle bracket (60,160) through which an outer member (61;161) of a telescopic tow bar provision (62;162) is slidable, and a docking bracket (64;164) to receive said outer member (61;161) when the tow bar provision (62;162) is extended for use.

11. A wheeled trailer according to claim 10, wherein the docking bracket (64;164) has releasable latching means (175A,B) for said outer member (161).

12. A wheeled trailer according to claim 10 or claim 11, wherein the turn-saddle bracket (160) is carried by extended mount (174) of the docking bracket (164).

13. A wheeled trailer according to claim 10, 11 or 12, wherein the tow bar provision (62;162) has a tow hitch (65) associated with its inner member (63), the tow hitch (65) being rotatable through a part turn for stowage below the main base part (11;111).

14. A wheeled trailer according to any one of claims 10 to 13, wherein stowage of the tow bar provision (61 etc;161 etc) is by release of the outer member (61;161) from the docking bracket (64;164), sliding the outer member outwards through the turn-saddle bracket (60;160), turning the outer member (61;161) with the turn-saddle bracket (60;160), sliding the outer member (61;161) back through the turn-saddle bracket (60;160), with retraction to within the width of the main base part (11;111).

15. A wheeled trailer according to any preceding claim, wherein a number plate and rear lights carrier (80;180)is extensibly and retractably associated with the main base part (11;111) at its underside.

16. A wheeled trailer according to claim 15, wherein the number plate and rear lights carrier (180) is foldable so as to be turned up at least partially above the main base part (111) when extended.