Curtain-sided, flat-top or skeletal trailers are constructed from steel and typically used to transport freight by coupling to a prime mover or truck. As their names suggest: a curtain-sided trailer has a fixed roof, rear doors and flexible movable curtains on its sides; a flat top trailer has no roof, rear doors or sides; and a skeletal trailer has rear doors and a roof and sides formed from spaced apart rails. The chassis according to the present invention is equally suited for all the above types of trailers.

BACKGROUND OF THE INVENTION A typical prior art curtain-sided trailer 100 is shown in Figs. 1 and 2 and includes wheels 102 at its rear end 110 and a support stand 106 towards its front end 108. A turntable connector (not shown) is positioned forward of the support stand 106.

The support stand 106 supports the trailer 100 in a substantially horizontal position when it is not coupled to a truck, as shown. The trailer 100 also includes a chassis 112 which supports a load table 114, as well as the wheels 102 and the support stand 106.

The trailer 100 can also include a body 104 which consists of doors (not shown) at the rear end 110, a roof 105 and side curtains 107.

As can be seen in Figs. 1 and 2, the chassis 112 typically comprises two support (I) beams 112a, 112b which extend along substantially the whole length of the trailer 100. The trailer 100 also includes belly lockers 116 which are attached below the load table 114 and around the support beams 112a and 112b.

Whilst this known arrangement provides for the attachment of belly lockers 116, those belly lockers 116 offer only limited volume due to them having to accommodate the protrusion of the support beams 112a and 112b. In particular, the height of the belly lockers 116 across the majority of their width (the region denoted 118) is only around 30 cm (12 in), which limits freight carrying options.

It is the object of the present invention to substantially overcome or at least ameliorate this disadvantage of the prior art.

SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is disclosed herein a chassis for a curtain-sided, flat-top or skeletal trailer, the chassis having: longitudinal support members; a load table supported by the longitudinal support members; a

forward turntable end; a rearward wheels end; and at least one belly locker of substantially constant open cross-section attached to the support members and longitudinally positioned between the turntable end and the wheels end.

The belly locker (s) is/are preferably a load bearing member (s) of the chassis.

In one form, the longitudinal support members include a cut-away section between the turntable end and the wheels end for at least partially accommodating the belly locker (s) therein.

In one embodiment of this form, the cut-away section is notched for partially accommodating the belly locker (s) therein. The locker (s) is/are preferably attached to the support members by welding at their upper surface (s) and by longitudinal straps at their lower surface (s).

In another embodiment of this form, the cut-away section is an opening for fully accommodating the belly locker (s) therein. The locker (s) is/are attached to the support members by welding around its/thier periphery/ies.

In another form, the chassis includes: first longitudinal support members underneath, and supporting, the load table; at least one said belly locker underneath said first support members; and second longitudinal support members underneath, and supporting, said locker (s). In this embodiment, the locker (s) is/are attached to the first and second support members by welding.

Preferably, the locker (s) includes a rectangular prism perimeter frame having two open sides.

The open sides preferably include vertical support members extending between upper and lower sides of the locker.

Typically, the locker (s) are approximately 800 mm in height and 3.5 to 4 m in length.

The support members are preferably I-beams or channel beams.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred forms of the present invention will now be described, by way of examples only, with reference to the accompanying schematic drawings, wherein: Fig. 1 is a side view of a prior art curtain-sided trailer; Fig. 2 is a cross-sectional view of the trailer shown in Fig. 1 along line 1-1; Fig. 3 is a side view of a trailer according to a first embodiment of the present invention; Fig. 4 is a side view of a trailer according to a second embodiment of the present invention; Fig. 5 is a cross-sectional view of the trailer shown in Fig. 4 along line 4-4;

Fig. 6 is a side view of a trailer according to a third embodiment of the invention; Fig. 7 is a top view of the trailer shown in Fig. 6; Fig. 8 is a partial side view of the trailer shown in Fig. 6; Fig. 9 is a side view of a support member assembly of the trailer shown in Fig.

6; Fig. 10 is an enlarged partial side view of the support member assembly shown in Fig. 9; Fig. 11 is an enlarged partial side view of the support member assembly shown in Fig. 9; Fig. 12 is an enlarged partial side view of the support member assembly shown in Fig. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Fig. 3 shows a first embodiment of a curtain-sided trailer 1 according to the present invention. The trailer 1 is produced from steel and has a chassis 2 with two longitudinal support members 3 supporting a load table 8, a support stand 4 and wheels 6. The chassis 2 includes a notched cut-away section 10 between the support stand 4 and the wheels 6 and a belly locker 12 of substantially constant open cross-section is partially disposed in the cut-away section 10.

The belly locker 12 is formed from a steel rectangular prism perimeter frame having a top wall 18, a bottom wall 20, side walls 17 and 19 and two open sides 14.

The locker 12 is approximately 800 mm high and 3.5 to 4 m long. The open sides 14 include vertical support members 16 extending between the top wall 18 and the bottom wall 20. The locker 12 is attached to the chassis 2 by welding adjacent its top wall 18 and the top portions of its side walls 17 and 19. Longitudinal steel straps 22 are also attached to the chassis 2 which pass under the bottom wall 20 of the belly locker 12.

The strength of the support members 3 of the chassis 2 is reduced by the removal of the cut-away section 10. However, the chassis 2 is reinforced by the welding thereto of the locker 12 to the support members 3, as the locker 12 becomes a load bearing member of the chassis 2 The addition of the longitudinal steel straps 22 also strengthens the support members 3, and thus the chassis 2. The vertical members 16 strengthen the locker 12, and thus the chassis 2.

Figs. 4 and 5 show a second embodiment of a curtain-sided trailer la according to the present invention. The trailer la is also produced from steel and has a chassis 2a having four longitudinal support members 2aa, 2ab, 2ac and 2ad. The chassis 2a also includes a longitudinal central section 10a where a belly locker 12a is disposed. As with the embodiment of Fig. 3, the locker 12a is configured as a

rectangular prism perimeter frame and includes a top wall 18a, a bottom wall 20a, side walls 17a and 19a and two open sides 14a. The open sides 14a includes vertical support members 16a extending between the upper side 18a and the lower side 20a.

As shown in Fig. 5, the upper support members 2aa and 2ab support the load table 8a. The locker 12a is disposed underneath support members 2aa and 2ab. The lower support members 2ac and 2ad are underneath the locker 12a and support it. The support members 2aa and 2ab join the support members 2ac and 2ad at sections 21a, as shown in Fig. 4.

The four support members 2aa to 2ad are smaller, and thus weaker, than the support beams of conventional trailers. However, similar to the first embodiment, when the locker 12a is welded to the longitudinal support members 2aa, 2ab, 2ac and 2ad, it becomes a load bearing member of, and reinforces, the support members 2aa, 2ab, 2ac and 2ad, and thus the chassis 2a.

Figs. 6 to 12 show a third embodiment of a skeletal trailer lb according to the invention. The chassis 2b of the trailer lb is similar to the chassis 2a of the trailer la shown in Figs 4 and 5 and is again produced from steel.

As best shown in Figs. 8 and 9, in this third embodiment, the chassis 2b has two support members 3b in the form of assemblies comprising a thinner (eg. 5mm thick steel plate) front section 22, a thicker (eg. 8mm thick steel plate) middle section 23 and a thinner (eg. 5mm thick steel plate) rear section 24. Small I-beams 25 extend between the support members 3b to support the load table 8b of the trailer lb.

The middle section 23 of each support member 3b includes a cut-away section 10b that forms a rectangular opening. The belly locker 12b is inserted into the cut- away sections 10b and is welded about its periphery to attach to it the support members 3b. The cut-away sections 10b reduce the strength of the support members 3b.

However, as with the first and second embodiments, the locker 12b becomes a load bearing member of the support members 3b, and reinforces them, and thus chassis lb overall.

The chassis embodiments described above provide an increased loading space of greater height than the prior art for carrying additional freight under the load table.

The additional freight can be palletised and thus can be loaded by fork lift. Dangerous goods or incompatible freight can also be segregated from the normal freight carried by the load table. Further, the lockers can be refrigerated or insulated to allow for the carrying of frozen or chilled goods. Carrying of freight in the lockers also lowers the centre of gravity of the trailer, thereby increasing stability.

Although preferred embodiments of the present invention have been described herein, it is apparent to those skilled in the art that the invention may be embodied in many other forms.

For example, removing the roof, rear doors and side walls from the curtain- sided trailer 1 would produce a flat top trailer.