Background to the Invention Trailers for use in transporting livestock generally comprise a number of levels each level having a platform to support the livestock. Such trailers enable livestock to be transported economically and efficiently. Trailers for supporting livestock may comprise an integrated cab plus transport area or comprise a trailer forming a livestock area to be towed behind a lorry.

The trailer may have at least one platform which is vertically moveable within the trailer in order for the height of the level to be adjusted according to the type of goods being transported. In livestock transporters, the height of the level will be dependent upon the type of livestock being transported. For example, a level supporting cattle will require a greater height than a level supporting poultry or sheep or pigs. Accordingly, it is advantageous for a trailer to have a platform which can move vertically within the trailer in order for the trailer to transport different goods efficiently and economically.

However, when a platform supporting goods is moved, the platform may not remain in a horizontal plane, especially, if the goods are not distributed evenly across the platform. This results from the drive means moving the platform higher vertically in regions supporting less weight. Prior art methods which try to address this problem have used a cog mechanism and hydraulic geared floor dividers in order for the platform to remain in a horizontal plane. However, such mechanisms are mechanically complicated and are difficult to clean. This is especially apparent in trailers for use in transporting livestock which need to be cleaned to a high standard frequently. Accordingly, such platforms can be restricting in transporting livestock.

It is an aim of the present invention to overcome at least on problem associated with the prior art whether referred to herein or otherwise.

Summary of the Invention According to a first aspect of the present invention there is provided a platform for use in a trailer, the platform being arranged, in use, to support goods thereon, the platform being movable by at least one piston wherein the extension of the piston is measured by a cable extension position transducer.

According to a second aspect of the present invention there is provided a trailer having a platform located therein, the platform being arranged, in use, to support goods thereon, the platform being movable vertically relative to the trailer by at least one piston wherein the

extension of the piston is measured by a cable extension position transducer.

Preferably, the platform is in accordance with the first aspect of the present invention.

Preferably the platform is movable vertically relative to the trailer Preferably the platform is movable by a plurality of pistons.

Preferably the or each piston is a hydraulic piston.

Preferably the or each piston is a multistage piston.

Preferably the trailer is arranged, in use, to transport dry freight. Preferably the trailer is arranged, in use, to transport livestock.

Preferably the platform comprises locking means to lock the platform in position relative to the trailer.

The locking means may comprise a locking track which may provide support portions to engage with a locking element located on the platform. The locking element may comprise a locking plate. The locking plate may be movable by a locking piston. The locking plate may be locked in position when the locking plate is engaged in a respective support portion.

The or each locking means may comprise signal means to indicate when the locking means is locked in position.

The platform may comprise controller means which indicates when all of the locking means are locked and the platform is locked in position.

According to a third aspect of the present invention there is provided a method of providing a trailer for use in transporting comprising supporting a platform within the trailer wherein the platform is movable vertically relative to the trailer by at least one piston and measuring the extension of the piston using a cable extension position transducer.

Preferably the or each piston is a hydraulic piston.

Preferably the or each piston is a multistage piston.

Preferably the method comprises providing two or three platforms. The method may comprise providing separate pistons for moving each platform.

The method may comprise moving the or each platform whilst the or each platform is supporting goods.

The method may comprise locking the platform in position relative to the trailer.

The method may comprise indicating when the platform is locked or unlocked relative to the trailer.

Brief Description of the Drawings The present invention will now be described, by way of example only, and with reference to the following drawings, in which:

Figure 1 is a side cross-section of a trailer for use in transporting livestock.

Figure 2 is a cross-section through a part of a platform for use in a trailer for use in transporting livestock.

Figure 3 is a cross-section through a part of another embodiment of a platform for use in a trailer for use in transporting livestock.

Figure 4 is a cross-section through a part of a platform for use in a trailer for use in transporting livestock.

Figure 5 is a cross-section through a cable extension position transducer.

Figure 6 is a cross-section through a part of a further embodiment of a platform for use in transporting livestock.

Figure 7 in a cross-section through X-X in Figure 6.

Description of the Preferred Embodiment A shown in Figure 1, a trailer 10 for use in transporting livestock comprises a plurality of levels.

The trailer 10 has a first level 12, a second level 14, and a third level 16 for supporting three levels of livestock. Each level has a platform 18,20,22 for supporting the livestock thereon. The height of each

level 12,14,16 is dependent upon the type of livestock being supported. Accordingly, it is advantageous for each platform 18,20,22 to be supported in the trailer 10 such that the vertical position of each platform can be adjusted in the trailer in order for the trailer to be adapted to transport different types of livestock. The platform 18 of the first level may be fixed since it is the floor of the trailer 10 and, therefore, cannot be moved vertically downwards.

As shown in Figure 2, it is important for each platform to be substantially horizontally supported in the trailer. With platforms 24 that are vertically adjusted using a hydraulic piston or ram 26 it is easy to locate a linear transducer (not shown) within the cylinder 28 in order to monitor and record the vertical extension of the extension member 28. However, platforms 24 for use in trailers generally need to be moved vertically over a relatively large distance. Accordingly, the extension member 30 needs to be extended over a substantial distance. This requires a relatively long extension member 30 and a corresponding cylinder 28. This, therefore, greatly restricts the amount that the platform can be lowered since the platform 24 must always be located above the cylinder 28 of the hydraulic piston, as shown in Figure 2.

Alternatively, a sleeve member 31 can be used to secure the platform 24 to the extension member 30 such that when the extension member 30 is retracted the platform 24 is at ground level within the trailer, as shown in Figure 3. One end of the sleeve member 31 is connected to the top of the extension member 30 and the

other end connects to the platform 24. The extension member 30 is connected to the platform 24 through the sleeve member 31 such that the platform is located vertically below the end of the extension member 30.

However, if a large single stage cylinder was used then the sleeve 31 would project upwardly from the platform 24 and possibly interfere with the other platforms or the roof of the trailer, for example, if the upper deck was required to be positioned relatively close to the roof of the trailer (for example, for small livestock) then the sleeve 31 and extension member 30 would need to protrude through the roof of the trailer, which is not acceptable in trailers.

A number of hydraulic pistons are required in order to raise and lower the platform 24 vertically relative to the trailer 26. These pistons are preferably located around the periphery of the platform 24. Alternatively, pneumatic or other suitably powered pistons may be used.

If the platform 24 has goods supported thereon and the platform 24 is raised or lowered then the distance that the extension members 30 of the pistons are extended may be different. This may result in part from the weight of the goods supported on the platform not being evenly distributed over the area of the platform 24.

Accordingly, in areas where a relatively low weight of goods are supported the platform may be moved upwardly more easily. Accordingly, it is necessary to measure the amount of extension of the extension members 30 in order to determine whether the platform 24 is substantially horizontal. In prior art methods, linear transducers have been used which secure within the cylinder of the pistons.

Such transducers are adequate for single stage pistons.

However, if multistage pistons are used to enable the platform to be raised and lowered over a greater distance then a simple linear transducer cannot be used.

In a preferred embodiment of the present invention a cable extension transducer 38 is used, as shown in Figure 4. A multistage piston has an extension member which comprises a plurality of stages 34,36 and a single cylinder 32. The advantage of multistage pistons is that the height of the housing only needs to be slightly greater than the length of the longest stage of the extension member. Accordingly, multistage pistons are useful in situations where space is important. However, linear transducers cannot be used to measure the overall length of extension of the extension member.

The cable extension transducer 38 is located adjacent to the cylinder 32 of the multistage piston. The cable extension transducer 38 has a flexible cable 40 which extends from a housing. The flexible cable 40 has a fixing plate 42 at the end thereof. The fixing plate 42 is secured to the end of the first stage 36 of the extension member. Accordingly, the cable extension transducer can measure the overall length of the extension member comprising a plurality of stages.

The cable extension transducer 38 comprises a housing from which the flexible cable 40 can be pulled out from, as shown in Figure 5. The flexible cable 40 is contained on a spool 44 in the housing. The flexible cable 40 may be a metal cable. The spool has spring means 46 associated therewith. The spring means urges the flexible cable to be wrapped around the spool 44. Accordingly, if

the length of the extension member shortens then the flexible cable is wound around the spool so that a new measurement may be taken. The cable extension transducer comprises a printed circuit board 48 for measuring and recording the length of the extension member and, accordingly, the position of the platform.

The trailer has a number of multistage pistons located around the periphery of the platform. A single control and measurement means may be used in order to co-ordinate the lifting and lowering of the platform in order to ensure that the platform is substantially horizontal after moving the platform.

As shown in Figure 6, the multistage piston is located within a sleeve member 39. The end of the upper stage 36 provides a ram socket 50 in order to co-operate with the upper end of the sleeve member 39 in order to move the platform 24. The trailer has a locking track 52 provided on its inner surface. The locking track 52 is provided with a plurality of supporting portions 54 which are arranged to engage with a locking element provided on the platform 24. The locking element is arranged to engage with the supporting portion 54 in order to support and lock the platform 24 in position relative to the trailer.

The locking track 52 may be adjustable in order for the space between adjacent supporting portions 54 to be altered depending upon the individuals requirements.

As shown in Figure 7, the locking element comprises a locking piston 56 which is connected to a locking plate 58. The locking piston 56 may be pneumatically, hydraulically or mechanically powered. As the platform 24

is moved upwards, the locking piston 56 and locking plate 58 automatically follow the profile of the locking track 52.

When the locking piston 56 is fully extended and the locking plate 58 is engaged in the supporting portion 54 of the locking track 52 a signal, preferably electrical, is transmitted from a sensor to a controller. The platform 24 has a plurality of locking elements located around its periphery and each locking element transmits a signal when the relevant locking piston is fully extended and engaged within a supporting portion. The controller monitors the signal and provides display means to display when all the locking pistons are fully extended and the respective locking plates are engaged in a supporting portion of the relevant locking track.

This provides a safety feature whereby the user is informed when the platform is safely engaged or is not fully engaged. The platform may be lowered by retracting the locking pistons using suitable means.

The locking pistons and locking plates may be arranged to automatically disengage when the multistage piston is powered.

One main advantage of the present invention is that it allows the exact position of each individual multi-stage cylinder extension height to be measured and controlled.

Once this position is known accurately it allows all cylinders to be independently controlled using computer control in order to maintain a perfectly level position.

Alternatively, the cylinders can be independently

controlled to angle the platform as desired, for example to ease the unloading of heavy loads or alternatively for animal transporters to ease the washing out process. This cannot be achieved so easily with prior art cog mechanisms or geared dividers.

In addition, each platform in the trailer may comprise the above system for measuring whether the platform is substantially horizontal.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment (s). The invention extend to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.