WO1991012976A1

WO1991012976A1 - Improved road trailer

Info

Publication number: WO1991012976A1
Application number: PCT/GB1991/000278
Authority: WO
Inventors: Frederick George Wilson
Original assignee: Wilson Double-Deck Trailers Ltd.
Priority date: 1990-02-24
Filing date: 1991-02-22
Publication date: 1991-09-05
Also published as: AU7302391A; GB9004220D0; ZA911352B; GB2241206A

Abstract

A road trailer comprising a forward section (10) adapted for attachment to a towing tractor and a rearward section (11) extending from the forward section (10), with at least one pair of wheels (13) rotatably attached to the rearward section (11). A tank (20) extends beneath the trailer bed (12) over substantially the whole length of the rearward section (11) and has a base (21) which is substantially planar lying at a level beneath the axis of rotation (14) of the wheels (13). The tank (20) may be formed with a spaced apart outer skin (23) and a load bearing foam (24) interposed in the space between the outer surface of the tank (20) and the outer skin (23).

Description

Improved Road Trailer

The invention relates to road trailers and more particularly to such trailers which can be used as a tanker for carrying bulk liquids or particulate products and for carrying general cargo.

United Kingdom Patent Specification No. 827,275 discloses a tanker trailer which has a semi-cylindrical bottom with a transverse clearance channel formed therein to allow passage of an axle. Hence such tank cannot be drained completely from the rear outlet.

United Kingdom Patent Specification No. 954,445 discloses a trailer with a load container located beneath a load carrying platform but not extending above the wheel axle. Hence a considerable volume of load carrying capacity is not utilised.

It is an object of the present invention to provide a trailer having a tanker capacity as well as normal load carrying capacity, which maximises the possible tank capacity beneath the trailer bed.

According to the invention there is provided a road trailer comprising a foreward section adapted for attachment to a towing tractor and a rearward section extending from the foreward section, with at least one pair of wheels rotatably attached to the rearward section, characterised by a tank extending beneath the trailer bed over substantially the whole length of the rearward section and having a base which is substantially planar lying at a level beneath the axis of rotation of the wheels. The base of the tank may be inclined downwardly from at least one longitudinal end thereof towards an outlet located at the bottom of the tank intermediate its longitudinal extremities. The tank may be formed with a spaced apart outer skin and a load bearing foam interposed in the space between the outer surface of the tank and the outer skin.

The tank and outer skin may be preformed and foam injected into the space therebetween, in situ.

An enclosed body may be located above the bed of the trailer.

Each wheel may be rotatably mounted on a stub axle carried by an air buffered suspension means. The tank may have a generally rectangular cross-section in both longitudinal and transverse extents thereof.

The foregoing and further features of the invention may be more readily understood from the following description of a preferred embodiment thereof, by way of example, with reference to the accompanying drawings, in which:-

Fig. 1 is a side elevational view of a road trailer;

Fig. 2 is a plan view of the trailer of Fig. 1;

Fig. 3 is a transverse cross-sectional view along the line XX of Fig. 1, on enlarged scale, and

Fig. 4 is a perspective view of the rearward end of the trailer of Figs. 1 and 2, on enlarged scale.

Referring now to the drawings there is shown a road trailer comprising a foreward section 10 which may be of conventional form for attaching to a towing tractor to form an articulated vehicle although this could alternatively be of the normal draw bar type construction. A rearward section 11 extends rearwardly from the foreward section 10 with a load carrying flat bed 12 extending over the whole length.

Two pairs of wheels 13 are located towards the rear of the rearward section 11. Each wheel 13 is mounted for rotation on a stub axle 14 (Fig. 4) which is carried on one corner of a generally triangular swing beam 15 which is hingedly mounted at point 16 to a transverse member 17. The upper corner of beam 15 is buffered by an air bag 18 with a shock absorber 19 located adjacent thereto.

A tank 20 extends beneath the trailer bed 12 over substantially the whole length of the rearward section 11 and has a base 21 which is substantially planar and lies at a level below the axis of rotation of wheels 13. A portion of the base 21, as shown dashed at 21a in Fig. 4, may be inclined towards an outlet 22 at the base 21 of tank 20. The tank 20 is formed with an outer skin 23 and a foam material 24, such as hard polyurethane, is injected into the space between tank 20 and skin 23, in situ. This has been found to produce an extremely robust and strong laminate, composite load bearing structure enabling the tank 20 to be produced from relatively thin sheet material, such as stainless steel sheet of 2 mm thickness. Furthermore such composite structure is utilised for transferring a part of the load from bed 12 to the wheel suspension assembly.

Although the trailer bed 12 is shown as flat, this could be stepped, and a housing 25 (Fig. 1) is preferably located above the bed 12 over its whole surface. The tank 20 may be divided into separate compartments with separate inlets and outlets for each.

Hence a trailer is herein disclosed which can be used for transporting normal loads on bed 12 and also liquids or particulate material, either together or alternatively in different directions of a particular journey. The arrangement allows maximum volume of tank 20 with the base being located as close to the ground as possible to give required clearance in use and maximum stability.

Claims

1. A road trailer comprising a foreward section adapted for attachment to a towing tractor and a rearward section extending from the foreward section, with at least one pair of wheels rotatably attached to the rearward section, characterised by a tank extending beneath the trailer bed over substantially the whole length of the rearward section and having a base which is substantially planar lying at a level beneath the axis of rotation of the wheels.

2. A trailer as claimed in claim 1 wherein the base of the tank is inclined downwardly from at least one longitudinal end thereof towards an outlet located at the bottom of the tank intermediate its longitudinal extremities.

3. A trailer as claimed in claim 1 or 2 wherein the tank is formed with a spaced apart outer skin and a load bearing foam interposed in the space between the outer surface of the tank and the outer skin.

4. A trailer as claimed in claim 3 wherein the tank and outer skin are preformed and the foam injected into the space therebetween, in situ.

5. A trailer as claimed in claim 3 or 4 wherein a composite structure comprised of the tank, outer skin and interposed foam is arranged to transfer a part of the load from the trailer bed to a wheel suspension assembly.

6. A trailer as claimed in any preceding claim wherein an enclosed body is located above the bed of the trailer.

7. A trailer as claimed in any preceding claim wherein each wheel is rotatably mounted on a stub axle carried by an air buffered suspension means.

8. A trailer as claimed in any preceding claim wherein the tank has a generally rectangular cross-section in both longitudinal and transverse extents thereof.