This invention relates to apparatus for indicating the load of an article and particularly, but not necessarily exclusively, to the measurement of a load which is imposed by each axle and/ or each wheel of a rail vehicle.

Rail track system operators impose limits on the weight of rolling stock to prevent excessive wear of the rails of the system and so rail vehicles, such as rail bogies, will be weighed from time to time when empty and/or when carrying passengers or goods to ensure that the same meets the required weight requirements. This has previously required either a fixed installation to be provided at a particular location on the rail system and typically in the form of a weighbridge. This is time consuming as the rail vehicle needs to be transported to the weighbridge.

A further option is to utilise more portable apparatus which can be installed at required locations on the rail system relatively quickly and efficiently. This therefore allows the weighing apparatus to be installed at locations where the rail vehicles are likely to be moving along the track in their normal usage. This therefore allows the weight of the rail vehicle to be performed more efficiently and in a shorter time. It is also found that the apparatus can provide a more accurate indication of the weight of the rail vehicle and can be used to indicate both static and dynamic axle and/or wheel loading of a rail vehicle.

This form of known apparatus typically comprises two load detection assemblies, each assembly including a support body, a load sensing device with a substantially convex contact surface, one or more strain gauges to detect the load imposed on the load sensing device and data transfer means which digitise the data from the strain gauges and allow the same to be transferred for ongoing processing. The assembly is fitted at the inner face of the rail and an assembly is provided for each of the rails of the track so that the load sensing device surface is engageable by the peripheries of the flanges of the wheels on an axle of the rail vehicle. Typically, the convex shaping of the contact surface is sufficient to raise the wheel just clear of the rails and locate the same with the load- sensing device. The assemblies are held apart and held against the respective rails by an adjustable support frame. An example of this type of apparatus is disclosed in the patent GB2315559.

At each of the load detection assemblies, there is typically provided a load detection device, typically in the form of a load cell assembly which is acted upon by the upper surface when contacted by the wheels and the load cell detects the change in weight applied thereto to provide a reading which can then be combined with the other load cell readings and the weight or load value for the rail vehicle as a whole is then determined.

However there are also problems with this form of apparatus.

One problem is that while the apparatus of the known type can be used to measure the load of a rail vehicle when the same is static or measure the load of a rail vehicle when the same is moving, this can only conventionally be achieved by using different forms of the apparatus. In order to be able to obtain the required weight average of a rail vehicle when in motion, the shoe or contact surface along which the vehicle's wheel is required to pass has to be of a longer length than a shoe or contact surface which is used for measuring the load of a static wheel. This is in order to allow the moving wheel to be in contact with the contact surface for a sufficient period of time to allow the load to be detected and calculated. As a result the shoe or contact surface of the conventional detection apparatus for use with moving wheels is typically at least 600mm in length. However, the rail fixings which locate the rails to the sleepers and which fixings are spaced along the rail, are commonly spaced apart by a distance of 600 mm or less which means that there is insufficient space between adjacent fixings to allow the "in motion" apparatus to be fitted at many locations without first having to remove fixings which in many cases will not be authorised by the track company and so the apparatus cannot be used or, if alteration of the track is allowed, there is still additional time and expense involved in removing and replacing the fixings. This therefore acts as a significant limitation of the ability to use the in motion version of the apparatus.

Another problem is that the load indicating means are typically provided in the form of a data processing and display unit which is connected to the load sensing device by one or more cable connections and located to one side of the rail tracks so that the same can be accessed by the user. This means that the cable connections are required to be laid under the rail to pass to an external side of the rail track and, while this is possible by locating or forming channels under the rail, it can be time consuming and restrict the locations at which the apparatus can be used. Furthermore, in most instances there is insufficient space available between the top surface of the track ballast and the rail vehicle as it passes along the track, to accommodate the data processing unit when provided in its conventional form. When the track in question is provided in a depot there may be a pit located under the track rails with no sleepers, and equipment may be provided there but there is still required to be cable connections to and from the same to data display means and so the trailing connecting cables, in any embodiment of use represent a potential health and safety risk and there is a risk that the cables can be come dislodged if the same is caught by personnel or other apparatus.

A problem with the load cells which are used is that the same are typically located in position with respect to the load detection assembly using one or more bolts. The bolts are received in apertures in the body of the assembly and the load cell is located with respect to the assembly by the location of the bolts therewith and with the assembly body.

It is found that the accuracy and/or proper operation of the load cell, is adversely affected by features of the bolt such as, the particular material from which the bolts are made, and variations therein, the accuracy of the thread in the bolts, the dimensions of the aperture in the body and/or the effect of different temperatures on the bolt. Each of these factors, alone or in combination, and possibly other factors, can mean that the accuracy of the load cell and the weight value provided, can vary over time and/ or can vary between different load cell assemblies and/ or can vary with regard to the environmental conditions at that time of use. These problems mean that the load cells themselves, and the apparatus as a whole, cannot be deemed to meet trade standards of accuracy and therefore can give rise to doubt as to the accuracy of the weight values that are provided by the apparatus.

It is therefore an aim of the present invention to provide the load detection apparatus in an improved form in which the problems indicated are overcome. A further aim is to provide the apparatus in a form which allows the same to be capable of measuring the load whether the load be from a rail vehicle which is static or a rail vehicle which is in motion and still allow the apparatus to be located in the relatively confined spaces which are available. A yet further aim is to provide a means whereby the load cell assembly can be mounted in position without the need to use bolts / set screws in the assembly. A further aim is to allow at least the load cell assembly to be tested to meet trading standards and therefore can be said to conform to set standards. A further aim is for the load cell assembly to be traceable, verified and hence minimise doubt or uncertainty as to the accuracy of weight values which are obtained using the apparatus.

In a first aspect of the invention there is provided apparatus for measuring the load imposed by an axle and/or wheel of a rail vehicle, said apparatus including at least one load detection assembly provided to be positioned at or adjacent to a rail of a rail track, each assembly including a body with respect to which a load sensing device with a contact surface is located so as to receive therealong at least part of a wheel of the rail vehicle and bear the load imposed thereby and measure the load and wherein the load detection assembly is capable of measuring the load imposed when the respective wheel is in a stationary position on the contact surface and/or when the respective wheel is moving along the contact surface within a predeteimined speed range, said body and/or contact surface including ramp portions to guide the wheel movement onto and/or from at least part of said contact surface.

Typically first and second load detecting assemblies are provided, a first assembly positioned at or adjacent to a first rail of the track and a second assembly positioned at or adjacent to a second rail, spaced from the first rail.

In one embodiment, the load sensing device is provided with a contact surface which includes a central portion which is typically slightly convex in shape. At either or both ends of the said portion the contact surface is provided with ramp portions which guide the wheel onto the load measuring central portion and off of the same and in one embodiment said ramp portions are formed integrally with and from the same body of material as which the load sensing device is formed. The load measurement can be taken along the length of the contact surface.

Typically, the ramp portions are required to be of a sufficient length such that the angle of the same is acceptable to allow for the safe guidance of the rail vehicle wheel from the rail onto the contact surface of the assembly and back onto the rail. In one embodiment the ramp portions provided as part of the contact surface act in conjunction with further ramp portions formed on the body of the load detection assembly so that at, or adjacent, each end of the contact surface there is provided a ramp formed by a ramp portion on the contact surface and a ramp portion formed on the body. The said ramp portions are provided to match to form, in combination, a continuous ramp in order to provide the required length and angle of ramp to guide the wheel therealong. The provision of the ramp portions integrated on the body and/or contact surface means that the overall length of the body and hence length of the assembly is reduced in comparison to conventional apparatus and thereby allows the advantages to be obtained as herein discussed.

Typically a central portion of the contact surface is located at the highest point of the load sensing device. In one embodiment first and second ramp portions are provided at opposing ends of the contact surface of the load sensing device.

In one embodiment the ramp portions are formed integrally with the load sensing device.

In one embodiment each load sensing device includes a data transfer means at which data from the strain gauges in the assembly are digitised.

Typically the digitised data is transferred by a wiring connection from the load detection assembly to the data processing module.

In one embodiment each load sensing device is secured to a support body of the load detection means and the support body and/ or load sensing device is adjustable in height to suit the cross-sectional profiles of different types of rails to which the apparatus may be required to be fitted.

In one embodiment the length of the body is less than 600mm, more preferably at or less than 575mm, and yet further may be in proximity of 500mm, to thereby allow the same to be fitted between adjacent rail fixings which are typically spaced apart by a greater distance. This therefore allows the load detection assembly to be fitted in position and used on the track and at different selected locations on the track without needing to alter the track or affect the integrity of the track.

This therefore allows the apparatus to have the ability of detecting and measuring a load when a rail vehicle wheel is static on the contact surface and also to be used to detect and measure a load when a rail vehicle wheel is moving along the contact surface at a speed which is below a predefined limit.

The forming of the ramp portions integrally with the said contact surface at either end of the central portion of the load sensing device allows the effective length of the contact surface of the load sensing device to be sufficient to detect the load when the rail vehicle is moving, whilst still providing the required ramps to guide the wheels whilst still allowing the load detection assembly to be of a sufficiently short length which can be fitted between adjacent rail fixings. This thereby prevents the need for any rail fixings to be removed as is conventionally the case, and/or allows the restrictions as to where the apparatus can be fitted, to be removed. This is also achievable as a result of the design of the body to include ramp portions and have sufficient strength to support the load sensing device whilst being shorter in length. In one embodiment the body is formed with a plurality of recessed portions formed to reduce the weight of the body and with support struts located between said recesses to provide strength to the body.

Thus, there is provided apparatus for measuring the load imposed by an axle and/or wheel of a rail vehicle, said apparatus including at least first and second load detection assemblies adapted to be clamped respectively in location with respect to first and second, spaced apart, rails of a rail track, each assembly including a load sensing device located with respect to the adjacent rail so as to receive therealong at least part of the wheel of the rail vehicle and bear the load imposed thereby and measure the load and wherein the apparatus is capable of being used to measure the load imparted by a rail vehicle when the vehicle is stopped with the wheel in contact with a contact surface of the load sensing device, and when the vehicle is moving, with the wheels moving along the contact surface of the load sensing device within a predetermined speed range.

In one embodiment the apparatus is located within an area which has opposing sides defined by the said rails and, typically the top of said area is defined by a plane substantially in line with the top face of the said rails of the rail track.

Typically the bottom of said area is defined by a plane substantially in line with the bottom face of the said rails of the rail track. In another embodiment the bottom of said area is below the rail track. In one embodiment one or more data processing modules are provided, when the apparatus is fitted in position for use as an integral part of a support frame for the apparatus.

Typically the data processing module is located on and supported by the apparatus.

Typically the data processing module is located intermediate said first and second load detection assemblies.

Typically the data processing module is located such that the same lies within that part of the rail track which is defined between the opposing rails. This therefore means that as the data processing means is located within the envelope of the rail track, no permanent cable connection is required between the data processing module and externally of the track. This therefore means that there is no longer a need for an access channel to be located under the track and so this no longer acts as a restriction on the location at which the apparatus can be used on the track.

In one embodiment it is the periphery of the flange of the wheel on an axle of the rail vehicle which contacts the contact surface of the load detection device and whereby the wheel is raised clear of the rail for at least part of the duration of the contact between the wheel and the load detection device.

In one embodiment, the data processing module includes a wireless data communication capability which allows the measurement data to be transmitted from the module to a remote location and, typically, for data to be communicated to the module from the same or another remote location to allow, for example, the memory or processing software of the module to be updated as and when required. In one embodiment, one of the remote locations may be an operator's laptop or PC which can be used to an external side of the track to allow measurement data to be received and analysed.

In one embodiment, the data processing module is provided with one or more power cells which may need to be replaced from time to time or may be rechargeable such as, for example, by the provision of a solar power charging unit mounted on the module or connected thereto. In one embodiment the power may be provided to allow the data processing to be performed but also to allow other functions to be performed, including, for example, the provision of heating to ensure that the data processing components are maintained at the required temperature range, the operation of the wireless communication means, such as Bluetooth (Registered Trade Mark), ZigBee (Registered Trade Mark) and/or mobile phone communication systems and/ or a location means to be able to identify the location of the apparatus.

In one embodiment, the data processing module has additional or alternative data processing capabilities including any, or any combination of, tagging means to detect tags located on the rail vehicle and thereby tag the identity of rail vehicles which pass over the apparatus; and/ or to detect the speed of the rail vehicle as it passes over the apparatus.

In one embodiment the apparatus includes a support frame which extends between the load detection assemblies and which allows the assemblies to be located adjacent the inner wall of the respective rails and retained in that position. In one embodiment the support frame includes one but, more typically first and second, elongate members which extend across the track to locate the respective assemblies located at each end of the elongate members. Typically the elongate members are adjustable in their length in order to allow the apparatus to be capable of being fitted to tracks of different widths. In one embodiment the data processing module is fitted to at least one, and, typically, where two are provided, both, elongate members at a position on the same intermediate the said assemblies. In one embodiment the engagement of the data processing module is via straps which are adjustable and can take into account movement of the apparatus due to rail flexing and/ or the weight of a rail vehicle on the shoes.

In one embodiment a plurality of data processing modules may be provided in location as described herein.

In one embodiment the assembly includes a load sensing device in the form of a load cell which is located and suspended with the body of the assembly by at least first and second spaced apart pins.

The location of the load cell assembly with the body means that the load cell assembly is effectively suspended on the pins which allows the load cell assembly to be tested to meet authority regulations prior to being fitted to the body. This is in contrast to conventional apparatus which as the load sensing device is provided as an integral part of the assembly cannot be tested or approved with respect to authority standards.

In one embodiment, the longitudinal axes of the pins are substantially perpendicular to the longitudinal axis of the surface which is contacted by the wheel of the rail vehicle.

Typically, the pins are located such that the same are prevented from moving out of the aperture in which the same are located but are free to rotate within the aperture.

Typically the load sensing device contact surface is located so as to be movable with respect to the body of the load detecting assembly and the movement of the said contact surface is caused by contact of the wheel flange of the rail vehicle with the contact surface. Typically therefore the movement of said contact surface relative to the body is translated into a weight value.

Typically the pins will incorporate an overload stop to protect the apparatus from overloading damage.

In one embodiment the pins include, but are not limited to a threaded engagement with the body.

In one embodiment the aperture which receives the pin will pass from one side of the body to the other whilst, in another embodiment, the aperture only passes partially across the body.

In a second aspect of the invention there is provided apparatus for measuring the load imposed by an axle and/ or wheel of a rail vehicle, said apparatus including at least first and second load detection assemblies which are provided to be positioned respectively at or adjacent to first and second, spaced apart rails of a rail track so that each assembly can receive there along at least part of a wheel of the rail vehicle and bear the load imposed thereby and measure the load and wherein data from the said load detection assemblies is passed to at least one data processing module located between said first and second load detection assemblies.

In a further aspect of the invention there is provided apparatus for measuring the load imposed by an axle and/or wheels of a rail vehicle, said apparatus including at least first and second load detection assemblies provided to be positioned at or adjacent to respective first and second spaced apart rails of a rail track, each assembly including a body with respect to which a load sensing device with a contact surface is located so as to receive therealong at least part of a wheel of the rail vehicle and bear the load imposed thereby and measure the load and wherein data representative of the load from the load sensing devices is wirelessly transmitted from the apparatus location to a remote location externally of the track for further use. In a yet further aspect of the invention there is provided apparatus for deterrrrining the weight of a rail vehicle located on a rail track, said apparatus including at least one load detecting assembly, said at least one assembly located adjacent to a rail of the track and positioned so that a contact surface of the assembly bears the weight of a wheel of the rail vehicle when the vehicle is at that location on the rail, said contact surface formed on a load sensing device to allow a load value to be determined and wherein the load sensing device is located and suspended with a body of the said at least one assembly.

In one embodiment the suspension is achieved using at least first and second spaced apart pins which are located in apertures in the body.

In a further aspect of the invention there is provided apparatus for measuring the load imposed by an axle and/ or wheels of a rail vehicle, said apparatus including at least first and second load detection assemblies provided to be positioned at or adjacent to respective first and second spaced apart rails of a rail track, each assembly including a body with respect to which a load sensing device with a contact surface is located so as to receive therealong at least part of a wheel of the rail vehicle and bear the load imposed thereby and measure the load and wherein the body is formed with one or more recessed areas to receive therein data processing means for the data generated by the load sensing device.

Specific embodiments of the invention are now described with reference to the accompanying drawings; wherein

Figures la and b illustrate schematically the apparatus in accordance with one embodiment of the invention in position with respect to a rail track;

Figure 2 illustrates the apparatus of Figure 1 in one embodiment in more detail; Figure 3 illustrates a load sensing device in accordance with one embodiment of the invention;

Figures 4a and b illustrate an elevation and plan view of a load detection assembly with the load sensing device of Figure 3;

Figure 5 illustrates, schematically, apparatus in accordance with one embodiment of the invention in location for use;

Figure 6 illustrates, schematically, a load sensing device in accordance with one embodiment of the invention;

Figures 7a to c illustrate views of a body formed for the reception of the load sensing device in accordance with one embodiment of the invention and;

Figures 8a-e illustrate a body of the load detection assembly in accordance with one embodiment of the invention.

Referring firstly to Figures la and b, there is illustrated apparatus in use in accordance with one embodiment of the invention. The apparatus 2 is shown in location with a rail track 4 which includes first and second rails 6,8 which are spaced apart b a distance X and which are mounted on sleepers 10 at spaced intervals as shown or in certain instances such as when provided in depot pits, only the rails are provided and a pit is located under the rails to allow access for repair to the underside of the rail vehicle. The particular dimensions of the sleepers, when provided, and/ or rails and the distance X between the rails, can vary depending on the geographical region at which the track to which the apparatus to be fitted is located.

The apparatus includes first and second support members 12, 14 which have located, at opposing ends, first and second load detection assemblies 16, 18. Located on the support members in this embodiment is a data processing module 20 which is connected, in this embodiment via cables or wiring 22,24, to data transfer means provided at the assemblies 16, 18.

The apparatus 2 is shown in more detail in Figure 2. It is shown how the support members 12, 14 are adjustable in length via threaded portions 26. This ensures that the support members can be adjusted to the required length for the distance X between the rails to which the apparatus is to be fitted and, in turn, ensures that the load detection assemblies are accurately located adjacent the inner wall 28 of the respective rails 6,8. The location of the load detection assemblies is required to be such that the load sensing device 30 of each assembly has at least a contact surface portion which is at a height to receive part of the wheel of the rail vehicle so that typically, the periphery of the flange of the wheel is located on the contact surface so that the wheel is raised clear of the rail at that time, the load is borne on the contact surface and a load detection is made by the load sensing device and data representing the same is passed to processing means to allow the readings for different wheels to be used to determine the load of the rail vehicle. The load sensing device can include strain gauges, provided in the load bearing assembly.

The load data from the assemblies is passed to the data processing module 20 which, in accordance with this embodiment of the invention is located intermediate the rails 6,8 and with an area which has a top which is at or below the plane of the top face of the rails and at or above the plane of the bottom face of the rails. The module is also attached to the support members 12, 14 via locators and straps 32, 34. The location of the data processing module within the rails means that no external cable connection is required to be passed from the area within the rails to either side of the rails and so the restriction on the location of the apparatus to be adjacent to a passage under the rails track is removed by _. the invention.

Typically, the data is transferred from the data processing module 20 to a remote location via wireless transmission as already described. In one embodiment of the invention there is provided the capability for the apparatus to be used to detect and measure the load of a wheel, the axles on which the wheels are mounted, and hence a rail vehicle, as the vehicle is held in a fixed position, with the respective wheels in contact with the contact surface of the respective load sensing devices and the apparatus can also be used to detect the load if the wheels are moving along the contact surface of the load sensing devices within a predetermined speed range. Conventionally this would have required two different versions of apparatus to be used, with a small length load sensing device required for stopped load detection and a longer length load sensing device required for moving load detection. The requirement for the longer length load sensing device has meant that in many instances the length of the load detection assemblies is such as to prevent the same from being located between the adjacent fixings of the rail to the sleepers, so that no use of the apparatus is possible, or the adjacent rail fixings have to be removed, which is time consuming, quite often requires additional authorities to be obtained and is therefore unsatisfactory.

These problems can be solved by the use of a load sensing device 30 in accordance with the invention and of a form shown in Figures 3 and 4a-b. The load sensing device 30 is provided, as is conventionally the case, with a contact surface 35 on a load sensing device provided on the load detection assembly at which the load of the wheel is borne and which includes a central portion 36. In accordance with the invention ramped portions 38, 40 are provided at each end of the contact surface which allow the guiding of the wheel from and to the rail. There is also provided a housing 42 which may include or be in contact with load sensing means such as strain gauges and slotted apertures 44,46 as shown to allow flexing of the device as the load changes.

A load detection assembly 16 in accordance with the invention is shown in elevation in Figure 4a and in plan in Figure 4b and shows the load sensing device 30 in position on a support body 50. It will be seen in this case that the central portion 36 and ramp portions 38,40 are provided as an integral load sensing device rather than as separate components, and so this allows the effective length of the load contact surface 35 to be sufficiently long as to be able to detect the load of a wheel which moves along the same. It will be seen that the support body includes further ramp formations 52, 54 which match with the respective ramp portions 38, 40 of the load sensing device 30 to form a continuous ramp at each end formed by body and load sensing device ramp portions and hence provide further guidance for the rail vehicle wheel onto and from the contact surface 35. It also means that the length of the load sensing device, and hence the load detection assembly is still small enough to allow the same to be accommodated within the space which is available between the fixings between rails and the sleepers on the majority, if not all, of the types of track with which the apparatus will be used. This means that the same item of _. apparatus is provided which is now capable of detecting the load of wheels when stopped or moving within the available space, without the need for removal of the rail fixings adjacent to the same.

In order to provide sufficient strength for the load sensing device 30 the lower arms 56 and 58 have been extended towards the ends of the ramp portions 38, 40, and the support body includes a back wall 60 to locate the load sensing device 30 in the correct position and prevent the load sensing device from twisting. The thickness of portions of the back wall are reduced by selectively locating recesses 72 therein as shown in Figure 8a which aEow the thickness and hence weight of the body to be reduced to a sufficient extent to aEow the apparatus to stiU be portable, whilst the location and provision of the struts 74 between the recesses allows the strength and integrity of the body to be maintained.

The load detection assembly 16 includes support handles 62,64 and the data transfer means 66 are indicated at the inner side 68 of the assembly. The ends of the frame support members 12, 14 are also shown in position. With reference to Figure 4b, the outer side 70 of the load detection assembly 16 is shown and it is this side which is positioned against the inner side of the rail so that the contact surface 35 of the load sensing device 30 can receive part of the wheel located on the rail of the track.

Referring now to figure 5, there is illustrated apparatus 102 in accordance with a further embodiment of the invention with respect to a rail track which comprises first and second spaced apart rails 104,106. The apparatus 102 includes first and second load detection assemblies 108, 110 which are located internally of and adjacent to the respective rails 104, 106 so as to bear the weight or load of the rail vehicle wheels as they pass over and contact the contact surface of the same.

As before, the load detection assemblies 108,110 are spaced apart and supported by elongate members 112, 114 which form a frame and weight value readings data from the load cell assemblies 116, 118 in the respective load detection assemblies are passed via cable connections 120 to a processing means 122 and then transmitted to a remote location for further processing. It should however be appreciated that the processing means 122 need not always be provided intermediate the rails and could be located externally of the rail track. In an alternative embodiment, there may be provided a data processing circuit board that is provided for each of the load cell assemblies and this may be located in recesses 72 or pockets in the load detection assembly body. The data can then be transmitted therefrom, by cable or wirelessly, to allow readings from the load cell assemblies to be collated and a weight or load for the rail vehicle calculated. Each board would correspond with each load cell assembly and the boards communicate to a receiver.

Figure 6 illustrates schematically an end sectional elevation along line A of Figure 5 and shows the manner in which one of the load sensing device_cells 116 is fitted with respect to the body 124 of the load detection assembly 108 and illustrates the manner in which the assembly has a contact surface 126 which is acted upon directly or indirecdy by the weight of the rail vehicle wheel. Also shown is the manner in which the load cell sensing device 116 is suspended in position with respect to the body 124 via pins 128, one of which is shown, and which passes through an aperture 130 provided in the load cell sensing device 116 and apertures 132, 134 provided in the walls 133, 135 of the body 124 as shown. In one embodiment the pin 128 is prevented from moving along its longitudinal axis 136 by a threaded engagement of the portion 138 of the pin in the threaded aperture 132.

Figures 7a -c illustrate the body 124 of the load detection assembly 108 in greater detail and illustrate that there are provided two pins 128, 140 spaced apart, and the pins are provided with the load cell sensing device 116 and pass through apertures 132, 134 and 132',134' respectively and serve to connect the load sensing device as shown on Figure 6 so as to suspend the load sensing device 116 in position with respect to the body 124 of the load detection assembly 108.

Thus, in accordance with the invention, there is provided apparatus which allows the reception and use of precertified and approved load cell assemblies as the load sensing device and thereby allows the traceability and consistency of use of the apparatus to be improved. Typically therefore, in this embodiment the load cell sensing devices are approved and certified by the suitable regulatory body as having a specified accuracy and this is done before the load sensing device is attached to the body to form the load detection assembly. It is not conventionally possible to have load sensing devices, once fitted as part of the portable apparatus, approved or certified and therefore the current invention overcomes this by allowing the load sensing devices to be approved and certified and then be subsequentiy fitted to the apparatus body by the provision of the pins which suspend the load sensing device in position with respect to the body.

The body 124 of the load detection assembly is shown in more detail in Figures 8a-e and shows the recesses 72 and struts 74 as previously discussed. Also shown are the location means 76, 78 for the elongate members 112, 114. The body 124 also includes the apertures 132, 134 and 132',134' for reception of the pins (not shown) of the load sensing device 116 and the position of the same, when fitted is illustrated by the cross hatched area with the contact surface 126 exposed . The load sensing device 116 is fitted on the side 80 of the body which faces the rail when the apparatus is in position for use. Once again, and although not shown, the body 124 and/or load sensing device 116 can be provided with ramp portions in, for example, the regions indicated by the letter Y to thereby allow the length of the body 124 to be reduced whilst maximising the adaptability and range of use of the apparatus.

The present invention therefore provides apparatus which is significantly more portable in terms of its ability to be placed at almost any location on a rail track and provide the added advantage of allowing moving and stopped rail vehicle wheel loads to be detected. The provision of the data processing module between the rails rather than to one side of the same also allows the ability to place the same at many locations on the rail track to be greatly increased thereby adding to the overall portability of the apparatus.