GB2264468A - Goods carrying road trailer - Google Patents

Abstract

A container-carrying road trailer for carrying containers of long, medium and short sizes, having a relatively movable chassis (10) and bogie (24), wherein the bogie is provided with a rearwardly extensible support (26) able to support a container which overhangs the rear of the chassis. <IMAGE>

Description

Goods Carrying Road Trailer This invention relates to a goods carrying road trailer.

Many goods carrying road trailers are used to carry containers, i.e. ISO containers.

ISO containers can in practice have several possible lengths, notably 6.1 m (20 ft), 9.15 m (30 ft) and 12.2 m (40 ft).

For transportation purposes, it is necessary for a container to be so positioned on the trailer that the load is satisfactorily distributed between the rear road axles and the king pin which joins the trailer to the towing vehicle.

However, for loading or unloading purposes, for example by means of a forklift truck, the container requires to be positioned with its rear end substantially aligned with the rear end of the trailer. It is difficult to provide a trailer which is capable of carrying all three sizes of ISO container, more generally referred to hereinafter as short, medium and long containers, whilst also being able to satisfy the required conditions both for transportation and for loading/unloading for each of the container sizes.

However, the present invention aims to provide a solution to this problem.

It is already known, for example from U.K. Patent Publication No. 2240753A, to equip a road trailer with a sliding bogie under the trailer chassis, which bogie carries the rear ground wheel axles on an associated suspension means. The chassis which carries the container has, relative to the bogie, a forward position in which a short container fixed on the chassis is appropriately positioned for transportation, and a rearward position in which the short container is appropriately positioned for loading/unloading.

According to the present invention, there is provided a goods carrying road trailer equipped with a sliding bogie carrying the rear ground wheel axles, the chassis being slidable relative to said bogie between forward and rearward positions respectively for locating a short container in transportation and in loading/unloading positions relative to the rear end of the trailer, wherein the bogie is provided with a rearwardly extensible support which, when extended from the bogie-when the chassis is in its forward position, enables the trailer to support a long container in a position appropriate for both transportation and loading/ unloading.

Assuming that, as is generally standard with ISO containers, a long container is twice the length of a short container, it follows that the trailer can alternatively carry two short containers. The trailer chassis, typically about 9.15 m (30 ft) long, can also support a container of this same length, but the positioning of such container is not correct for transportation unless the bogie is in its rearward position (chassis in forward position). In the present case, the trailer can carry a medium container, in a position suitable for both transportation and loading/unloading, if the chassis travel relative to the bogie between its forward and rearward positions is equal to at least one half the difference in lengths between a short container and a medium container.This means that, in the case of standard ISO containers, the chassis travel relative to the bogie should be at least 1500 mm. Assuming the chassis travel is about 1500 mm or a little more, the bogie requires to be extensible by about 1500 mm or a little less. The trailer will then carry the medium container with the bogie in its rearward position (chassis in its forward position relative to the bogie), with the bogie extension retracted.

As, in the case of a medium or long container, the rear end of said container is supported by the bogie, the extensible support being retracted in the case of a medium container and extended in the case of a long container, the extensible support preferably includes, at its rear end, a load engaging means which, when appropriate, can be raised into a load bearing position. This load engaging means is not required in the case of a short container, and is kept lowered. The load engaging means conveniently comprises two load-engaging members carrying container twist locks, manually raisable and lowerable.

In order to facilitate sliding movement between the chassis and the bogie, either one or the other or both, usually the bogie, is provided with grease pads, plastics (nylon) pads or rollers, or a combination thereof, which minimise sliding friction between one said member and the other.

Sliding movement of the chassis relative to the bogie is achieved, in a conventional manner, by forward or backward movement of the towing vehicle (or tractor), in conjunction with appropriate application of the brakes to the rear wheels (the wheels carried by the bogie), and also release of a bogie locking mechanism. The latter mechanism may, in known manner, comprise a cam system operating on locking pins situated on either side of the bogie, the cam system being powered by an air cylinder. Alternatively, the locking mechanism may be manually operable.

Extension or retraction of the extensible support on the bogie may be effected by one or more air cylinders or hydraulic fluid cylinders, utilising power derived from the towing vehicle. Alternatively, the extension may be manually movable, through gearing or a rack and pinion.

The trailer chassis and bogie are equipped with all the container twist locks, conventional in the art, necessary to lock in position any of the containers of different sizes.

A road trailer in accordance with the invention is exemplified in the following description, making reference to the accompanying drawings, in which Figure 1 shows the trailer diagrammatically in side elevation; Figure 2 is a diagrammatic cross-sectional view of the chassis and bogie of the trailer; Figure 2A is a diagrammatic rear end view of one side of the extended bogie; and Figures 3A to 3D show the trailer in various conditions of use.

ISO containers to be carried by road trailers essentially exist in three standard sizes, namely having lengths of 6.1 m (20 ft), 9.15 m (30 ft) and 12.2 m (40 ft). The present invention especially concerns a road trailer able to carry containers of these dimensions. The dimensions of and relating to the trailer are therefore also of importance, and where appropriate are marked in the accompanying drawings.

Referring to Figures 1 and 2, the illustrated road trailer has a main frame or chassis 10 equipped with bolsters 12 having fittings which, together with cooperating fittings on a container 14, form conventional container locks 16 for fixing the container in a correct position of support on said chassis.

When not being towed, the chassis itself is supported between the rear wheels 18 and a front stand 20; during travel the chassis is supported between the rear wheels 18 and a king pin connection 22 with the towing vehicle or tractor (not shown).

The rear wheels 18 are, via a suitable suspension means, carried by a bogie 24, with which, by means of grease pads, nylon pads or rollers, the chassis 10 is supported in relative sliding relationship in the longitudinal direction.

Sliding of the chassis 10 relative to the bogie 24 is effected, in a conventional manner, by use of the towing vehicle, in conjunction with application of brakes to the rear wheels 18 and release of a bogie lock. The bogie lock is conveniently constituted by locking pins, which may be manually operable or operable by a power driven cam system.

Forward and rearward positions of the chassis relative to the bogie are determined by positive front and rear stop brackets (not shown).

The aforesaid chassis 10 and sliding bogie 24, as thus far described, are conventional. One known sliding chassis/ bogie arrangement is described in U.K. Patent Publication No.

2240753A.

However, the bogie 24 of the present invention is provided with a rearwardly extensible support 26 which, when extended, is capable of supporting the rear end of a container which overhangs the rear end of the chassis 10. The extension 26 is displaceablevby means of one or more suitable air or hydraulic cylinders deriving power from the towing vehicle.

Reference is now made to Figures 3A to 3D of the drawings.

Figure 3A shows that, with the chassis 10 in its forward position relative to the bogie 24, and with the extensible support 26 extended, the trailer can carry a long (12.2 m) container 28. Alternatively, it can carry two short (6.1 m) containers in end to end relationship.

The rear end of the extensible support 26 is provided with a raisable load engaging means 30, equipped with container twist lock fittings, for load bearing engagement with the rear end of the long container. Thus, Figure 2 indicates that the bogie comprises side or longitudinal box section members 40 interconnected by cross members 42. The extensible support 26 conveniently includes box section members 44 which slide into and out of the bogie side members 40. Figure 2A shows that the rear ends of the extensible members 44 of the bogie carry short box section uprights 46 from which inner box section members 48 can be raised to support the rear end of a container. The members 48 can readily be raised and lowered manually, and fix in position by locking pins 50.

Said members 48 carry container twist lock fittings 52 at the top.

Figure 3B shows that, with the extension 26 retracted, but the chassis 10 still in its forward position relative to the bogie 24, the trailer can carry a medium (9.15 m) container 32. Although the extension 26 is retracted, the raisable load bearing means 30 is still employed.

Instead of the load engaging means shown in Figure 2A, it may be preferred to employ a pivotted flap means at the rear end of the extensible support 26, which flap means is raised into load bearing engagement with the container.

Conveniently, the front container twist lock for the medium container 32 is shown in each of Figures 3A and 3D by the reference 34. This container lock 34 is indicated by way of example to enable the relative positions of differently sized containers on the chassis 10 to be clearly seen. In practice, however, the chassis 10 and bogie 24 are equipped with container locks for the front and rear ends of all container sizes, when these are correctly positioned on the chassis.

Referring now to Figure 3C, this shows a single short (6.1 m) container 36 in a position for transport on the trailer.

The extensible support 26 is retracted, but the chassis is still in its forward position. The container 36 is thus located forwardly of the rear end of the trailer, so that the load is correctly distributed during travel between the king pin connection 22 with the towing vehicle and the rear wheels 18. In Figure 1, reference 38 denotes the centre load position of the chassis, which typically has a 25 tonne load rating.

Figure 3D shows the trailer supporting the small container 36 in a position for loading and unloading. In this case the chassis 10 is in its rearward position relative to the bogie 24, thus bringing the container into alignment with the rear end of the trailer.

Referring back to Figures 3A and 3B, it will be seen that, in the case of the long and medium containers, 28 and 32 respectively, the container is always supported substantially in alignment with the rear end of the trailer, and no sliding movement between the chassis 10 and the bogie 24, nor movement of the extensible support 26, is necessary to change between the conditions of travel and of loading/unloading. The container lock on the load engaging means 30 at the rear end of the retracted bogie extension is not used in the case of a short container, and this load engaging means is lowered.

It will be appreciated that certain dimensions of the chassis 10, bogie 24 and extensible support 26 are of critical importance to the above-described trailer for carrying differently sized standard ISO containers. These important dimensions are therefore marked in Figure 1. It will be noticed, in particular, that the sliding travel of the chassis/bogie is 1700 mm, i.e. a little more than half the length of a short container, whilst the extensible support is extensible through 1350 mm, i.e. a little less than half the length of a short container. These dimensions could possibly be more substantially equal, both close to 1500 mm.

More generally, either the bogie travel or the bogie extension could vary by up to 250 mm either way from the above specified distances.

Various modifications of the above-described and illustrated arrangement are possible within the scope of the invention hereinbefore defined.

Claims (15)

Claims

1. A goods carrying road trailer equipped with a sliding bogie carrying the rear ground wheel axles, the chassis being slidable relative to said bogie between forward and rearward positions respectively for locating a short container in transportation and in loading/unloading positions relative to the rear end of the trailer, wherein the bogie is provided with a rearwardly extensible support which, when extended from the bogie when the chassis is in its forward position, enables the trailer to support a long container in a position appropriate for both transportation and loading/unloading.

2. A trailer according to claim 1, wherein the chassis travel is about 1500 mm or a little more.

3. A trailer according to claim 2, wherein the bogie is extensible by about 1500 mm or a little less.

4. A trailer according to any of claims 1 to 3, wherein the extensible support includes, at its rear end, a load engaging means which, when appropriate, can be raised into a load bearing position.

5. A trailer according to claim 4, wherein the load engaging means comprises two load-engaging members carrying container twist locks, manually raisable and lowerable.

6. A trailer according to claim 5, wherein the loadengaging members comprise pivotted flap means.

7. A trailer according to any of claims 1 to 6, wherein the chassis and the bogie, either one or the other or both, is or are provided with grease pads, plastics (nylon) pads or rollers, or a combination thereof, which minimise sliding friction between one said member and the other.

8. A trailer according to claim 7, wherein the pads or rollers are carried by the bogie.

9. A trailer according to any of claims 1 to 8, having a bogie locking mechanism comprising a cam system operating on locking pins situated on either side of the bogie.

10. A trailer according to claim 9, wherein the cam system is powered by an air cylinder.

11. A trailer according to claim 9, wherein the locking mechanism is manually operable.

12. A trailer according to any of claims 1 to 11, wherein extension or retraction of the extensible support on the bogie is effected by one or more air cylinders or hydraulic fluid cylinders, utilising power derived from the towing vehicle.

13. A trailer according to any of claims 1 to 11, wherein the extension is manually movable, through gearing or a rack and pinion.

14. A trailer according to any of claims 1 to 13, wherein the trailer chassis and bogie are equipped with container twist locks for locking in position containers of different sizes.

15. A road trailer substantially as hereinbefore described with reference to the accompanying drawings.