Trailer nose weight measuring device

Abstract

A trailer and vehicle hitching assembly comprises: a coupling body for mounting to a body of one of the trailer or the vehicle; a hitch portion including a coupling head for removably hitching the trailer and vehicle hitching assembly to the other of the trailer or the vehicle, a tubular connecting portion arranged between the coupling body and the coupling head; and a device suitable for measuring strain. The trailer and vehicle hitching assembly is configured such that a central longitudinal axis of the tubular connecting portion is aligned with a sagittal plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle. The tubular connecting portion is hollow thereby forming an inner wall. The device suitable for measuring strain is affixed to the inner wall of the tubular connecting portion. An axis of the device suitable for measuring strain is aligned with the sagittal plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle.

Description

[0001] Trailer Nose Weight Measuring Device

[0002] Field

[0003] The present invention relates to a trailer and vehicle hitching assembly for measuring the nose weight of the trailer. It also relates to a trailer nose weight measuring system and trailer having such an assembly or system.

[0004] Background

[0005] When towing a trailer behind a vehicle, it is crucial that said trailer is not overloaded. By having too great a load in the trailer, the trailer and vehicle can become unsafe to operate due to the excessive weight causing an impairment in the vehicle's ability to steer and brake properly. Furthermore, it can make the vehicle and trailer unstable when going around corners and the additional weight can cause strain on the tyres and other components, potentially resulting in an earlier failure condition than would be normal. As such, many countries have put in place weight restrictions on trailers that must be adhered to, else the driver of the vehicle risk legal punishment. This weight restriction legislation often includes nose weight, also known as the S weight, of the trailer. Nose weight here refers to the static load exerted by the trailer on the towing vehicle at the coupling point, due to the trailer's weight. For instance, in the EU, Directive 96 / 53 / EC sets limits on the combined weight of the towing vehicle and trailer, along with specific trailer restrictions. For most passenger vehicles, the maximum permissible weight of a trailer without brakes is 750 kg, and with brakes, it can be up to the vehicle's towing capacity, as specified by the manufacturer. Additionally, the directive includes limits on the nose weight. Directive 96 / 53 / EC mandates that the nose weight must not exceed the lower of the manufacturer's specified limit or 4% of the actual trailer weight.

[0006] While some users, for example those forming part of businesses involving the use of trailers, might have separate external devices that they can attach to the front of a loaded trailer to measure the nose weight, many users (such as those with personal trailers or caravans) do not have access to such equipment. Without effective ways to measure nose weight, users can face safety and usability challenges, potentially leading to improperly balanced loads that can make handling difficult and increase the likelihood of accidents. As such, incorporating a method of measuring the trailer nose weight into the trailer or vehicle would allow users to ensure they are meeting the relevant road and loading regulations easily and quickly at any location (as well as ensuring safe handling of the vehicle and trailer), rather than having to find the owner of a suitable measurement device. Figures 1 and 2 show an example of such a vehicle and trailer system 10 according to the known prior art, comprising a trailer 20 affixed to a vehicle 30. The trailer 20 is formed around a frame 21 which culminates in a tongue 22 supported by a jockey wheel 23. Mounted to the tongue 22 is a coupling 24, formed from a coupling body 25 (affixed to the tongue 22) and a coupling head 27, with a draw tube 26 (also known as a drawbar) therebetween. The coupling head 27 has a downward facing recess 28. A tow bar 32 is mounted to the rear of the vehicle 30, the tow bar 32 having a tow hitch 34 culminating in a ball 36. The shape of ball 36 corresponds to the shape of the recess 28, such that the front of trailer 20 can be raised via the jockey wheel 23 to have the ball 36 sit in the recess 28, allowing the towing of the trailer 20 by the vehicle 30.

[0007] One known solution is to have multiple measuring devices located around the tongue 22 of trailer 20. However, this does not produce a straightforward nose weight reading, and as such multiple calculations must be done to determine an accurate trailer nose weight. As well as being more computationally difficult, these calculations also introduce potential errors and inaccuracies into the final reading.

[0008] Another known solution is to place a measuring device on an inside surface at point 29 of the recess 28 of coupling head 27. By placing the measuring device at point 29 (the uppermost part of recess 28 and where the curvature of recess 28 is at a horizontal), the trailer nose weight can be measured from the force exerted upon the device. However, the contact between this point 29 and the ball 36 of towbar 32 can cause wear or damage to the measuring device. As such, over repeated use, the wear experienced by the measuring device will cause inaccuracies in the trailer nose weight reading.

[0009] The present invention seeks to overcome or at least mitigate these problems by providing a system in which the trailer nose weight can be accurately measured over an extended period of use. The present invention also seeks to provide such a system that is reliable, easy to manufacture and very cost effective.

[0010] EP2280263 discloses a towball load measuring device temporarily couplable to a trailer device for an unhitched trailer in the force path between trailer device and the ground surface, comprising at least one force measurement sensor arranged in the force path between the trailer device and the ground surface for measuring at least the towball load transmitted via the trailer device; and a sensor housing of weatherproof design comprising at least the force measurement sensor. EP2280263 discloses a first embodiment in which force measuring sensors are mounted on a trailer coupling on a vehicle. EP'63 discloses a second embodiment in which force measuring sensors mounted on an inner surface of a drawbar which forms part of a trailer chassis.

[0011] US2019 / 0070915 discloses a system in which strain sensors are positioned on the vertical sides and longitudinal sides of a support arm forming part of a device for pulling a trailer and / or retaining a load carrying unit that is mountable at the rear end of a motor vehicle body.

[0012] US2013 / 0080078 discloses a system for determining the tongue weight of a towed vehicle and other parameters includes a drawbar transducer in one embodiment and a receiver hitch transducer in another embodiment. Strain gauges are located on the transducer and information regarding the towed vehicle are sent to a display.

[0013] US2023 / 0211640 discloses a hitching system for connecting a towed vehicle to a towing vehicle comprising: a connector member for engaging with a connection point on the towing vehicle; a shaft member connected at one end to the connector member and at a second opposing end to a housing fixed to the towed vehicle; a plurality of sensor elements mounted to said shaft member, at least one of the sensor elements configured to measure a lateral force present in the shaft member during towing of the towed vehicle by the towing vehicle; and a computer processor mounted with respect to the towed vehicle for receiving a signal from at least one of the sensor elements representative of the measure of the lateral force present in the shaft member and processing said signal to control motion of the towed vehicle.

[0014] US2005 / 0006952 discloses an arrangement for measuring the braking forces acting on a vehicle trailer with a rigid hitch arrangement. The arrangement includes strain gauges mounted on a pipe which is rigidly connected at its front end with the trailer coupling, which are positioned along the neutral axis to minimise capture of bending stresses, vehicle.

[0015] Summary

[0016] A first aspect of the invention provides a trailer and vehicle hitching assembly comprising: a coupling body for mounting to a body of one of the trailer or the vehicle; a hitch portion including a coupling head for removably hitching the trailer and vehicle hitching assembly to the other of the trailer or the vehicle, a tubular connecting portion arranged between the coupling body and the coupling head, the trailer and vehicle hitching assembly being configured such that a central longitudinal axis of the tubular connecting portion is aligned with a sagittal plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle, the tubular connecting portion being hollow thereby forming an inner wall; and a device suitable for measuring strain affixed to the inner wall of the tubular connecting portion, wherein an axis, for instance, a longitudinal axis, of the device suitable for measuring strain is aligned with the sagittal plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle.

[0017] The term "sagittal plane" as used herein refers to a vertical plane that divides the trailer or vehicle into left and right halves, running along its longitudinal axis from front to back. While this plane is vertical relative to the trailer / vehicle itself, its orientation may tilt or incline with the trailer / vehicle if the trailer / vehicle is positioned on an uneven surface, such as a cambered road. The plane may be a central, or medial, sagittal plane, which bisects the trailer / vehicle into equal halves. The central longitudinal axis may define a centroid of the tubular connecting portion.

[0018] By affixing the device suitable for measuring strain to the inner wall of the tubular connecting portion, the device suitable for measuring strain is further protected from wear (for example by stone strike or road debris when in use), which increases the lifespan and long-term accuracy of the system. Further, according to this arrangement, the strain measuring device is located at a point at which bending deformation due to the nose weight are at a maximum. Thus, a direct measurement can be taken that (after unit conversion) can be output to indicate trailer nose weight (S weight) without the need for any major calculations that could introduce inaccuracies.

[0019] The invention differs from the prior art arrangements described above. For instance, EP2280263 does not disclose a device suitable for measuring strain on an inner wall of a tubular connecting portion arranged between a coupling body for mounting to a body of one of a trailer and a vehicle and a coupling head for removably hitching to the other of a trailer and a vehicle. In EP2280263 the sensors are mounted to a drawbar which forms part of the trailer chassis, or body itself. This drawbar therefore does not constitute a connecting portion for mounting to the body of the trailer via a coupling body, as per the present invention. EP2280263 further does not disclose a device suitable for measuring strain having an axis aligned with the sagittal plane of the vehicle or trailer it is coupled to, which itself is aligned with the central longitudinal axis of a tubular connecting component.

[0020] US2019 / 0070915 does not disclose devices suitable for measuring strain mounted to an inner wall of a tubular connecting portion, as in the first aspect of the present invention. US2013 / 0080078 does not disclose strain measuring devices mounted to a tubular connecting portion, as in the first aspect of the present invention.

[0021] US2023 / 0211640 does not disclose strain measuring devices affixed to an inner wall of a tubular connecting portion, as in the first aspect of the present invention.

[0022] US2005 / 0006952 does not disclose an arrangement in which the device suitable for measuring strain is affixed such that the axis of the device suitable for measuring strain is aligned with the sagittal plane of the vehicle or trailer it is coupled to, which itself is aligned with the central longitudinal axis of the tubular connecting portion. In contrast, in US2005 / 0006952, the strain gauges are mounted at the neutral axis of the pipe section. As a result, the arrangement of US2005 / 0006952 is does not measure nose weight.

[0023] The cross sectional shape of the tubular connecting portion is not limited. In some embodiments, the cross-sectional shape of the tubular connecting portion is one of a square, rectangular, ovoidal, or circular cross-sectional shape. The internal space formed by the hollow body of the tubular connecting portion may have substantially the same cross-sectional shape as the tubular connection portion. This allows for a greater accuracy of strain measurement.

[0024] Optionally, the coupling body is configured to be mounted to a tongue portion of a trailer. This tongue portion may form part of the trailer chassis, or frame.

[0025] The device suitable for measuring strain may be affixed to the inner wall of the connecting portion via one of welding or adhesives. These methods of affixing the device suitable for measuring strain to the inner wall provide the necessary secure attachment required for accurate strain measurements in the hitching assembly.

[0026] The device suitable for measuring strain may be positioned on the tubular mounting component at a longitudinal location at which bending stress in the tubular mounting component is at a maximum. Optionally, the device suitable for measuring strain is located towards the coupling body. Optionally, the device suitable for measuring strain is located at the end, for example the extreme end, of the tubular connecting component which is adjacent the coupling body.

[0027] The device suitable for measuring strain may be located in a mounting component. The mounting component may be affixed to an inner wall of the tubular connecting portion. The mounting component may have at least one surface shaped to conform with the wall of the tubular connecting portion. The use of a mounting component allows for improved manufacturing, as the device suitable for measuring strain can be protected until fitted and more easily and accurately positioned on the connecting portion, whilst still providing the secure connection required for accurate measurements.

[0028] The mounting component may be affixed to, and conform with, a curved wall of the connecting portion. The mounting component may be manufactured from a flexible, or more preferably, a semi-rigid material such as one or more of polypropylene (PP), polyethylene (PE), poly(methyl methacrylate) (PMMA), nylon, acrylonitrile butadiene styrene (ABS).

[0029] The tubular connecting portion may lie on a vertical plane bisecting the trailer in a longitudinal direction, the device suitable for measuring strain being substantially parallel with the vertical plane. The device suitable for measuring strain may further have an axis, for example, a longitudinal axis, this axis may be substantially coincident to the vertical plane.

[0030] Optionally, the device suitable for measuring strain is affixed at a lowermost part of the inner surface, or inner wall, of the tubular connecting component. Such a positioning of the device may be referred to as the "6 o'clock position". Alternatively, the device suitable for measuring strain is affixed at an uppermost part of the inner surface, or inner wall, of the tubular connecting component. Such a positioning of the device may be referred to as the "12 o'clock position".

[0031] The trailer and vehicle hitching assembly may further comprise a second device suitable for measuring strain affixed to a wall of the tubular connecting portion. This second device suitable for measuring strain may be affixed to a wall of the tubular connecting portion opposite the first device suitable for measuring strain. This second device suitable for measuring strain adds redundancy to the system, improving reliability, whilst increasing accuracy by allowing for comparison of measurements. Optionally, the axes of both the first and second devices suitable for measuring strain are aligned with a sagittal plane of the vehicle or trailer which itself is aligned with the central longitudinal axis of the tubular connecting component. In some embodiments, the trailer and hitching vehicle assembly may include two devices suitable for measuring strain: a first affixed to a lowermost part of the inner wall of the tubular connecting component (at the "6 o'clock position"), and a second affixed to an uppermost part of the inner wall of the tubular connecting component (at the 12 o'clock position"). The first and second devices may both be positioned at substantially the same longitudinal position along the tubular connecting component. In this setup, the strain measuring devices placed at the 12 o'clock and 6 o'clock positions along the longitudinal axis of the tube can be used to calculate the static load by comparing the strain measurements. When the static downward load from the weight of the trailer is applied to the tubular component the load creates a bending moment. This bending moment causes the tubular connecting component to experience compression on one side and tension on the opposite side. For instance, one strain measuring device will measure strain corresponding to tension and one strain measuring device will measure compression. The difference in the strain readings between these two positions reflects the bending deformation caused by the static load which is proportional to the static load applied at the coupling point.

[0032] Optionally, the trailer and vehicle hitching assembly includes four devices suitable for measuring strain, each mounted to an inner wall of the tubular connecting portion, the devices being equally angularly spaced around the inner wall of the tubular connecting portion. Optionally, the axes of all four of the first, second, third and fourth devices suitable for measuring strain are aligned with the sagittal plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle, said sagittal plane being aligned with a central longitudinal axis of the tubular connecting component when the coupling body is mounted to the body of said one of the vehicle or the trailer. Optionally, the axes of both the third and fourth devices suitable for measuring strain are aligned with a transverse plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle, said transverse plane being aligned with a central longitudinal axis of the tubular connecting component. Accordingly, in some embodiments, the trailer and hitching vehicle assembly may include four devices suitable for measuring strain: a first affixed to a lowermost part of the inner wall of the tubular connecting component (at the "6 o'clock position"), a second affixed to an uppermost part of the inner wall of the tubular connecting component (at the 12 o'clock position"), a third affixed to a part of the inner wall of the tubular connecting component located 90 degrees counterclockwise from the lowermost part (at the 9 o'clock position’), and a fourth affixed to a part of the inner wall of the tubular connecting component located 90 degrees clockwise from the lowermost part (at the '3 o'clock position'). All four devices suitable for measuring strain may be positioned at substantially the same longitudinal position along the tubular connecting component.

[0033] The arrangement involving four strain measuring devices advantageously enables the more accurate calculation, not only of the nose weight (or S force), but also of the dynamic force (or D force) transmitted through the coupling between the towing vehicle and the trailer which arise from acceleration, braking, cornering, swaying, and road surface variations. Although the arrangement described above including two strain measuring devices do, to some extent, capture tension or compression caused by dynamic forces, the strain measuring devices positioned at the 12 o'clock and 6 o'clock positions primarily capture the upward and downward components of the S force, the additional strain measuring devices at the 3 o'clock and 9 o'clock positions are able to effectively capture the lateral forces (side-to-side) that occur during dynamic events like cornering or swaying. Accordingly, by including four strain measuring devices, arranged as described above, a more accurate and complete understanding of the dynamic forces acting on the coupling can be achieved.

[0034] The, or each, device suitable for measuring strain may be a strain gauge. The, or each, strain gauge may be a thin film strain gauge. These strain gauges are cost efficient and reliable methods of strain measurement.

[0035] The trailer and vehicle hitching assembly may be a movable hitching assembly. In other words, the trailer and vehicle hitching assembly may include an overrun mechanism. The overrun mechanism is a type of coupling that allows the trailer to move relative to the towing vehicle during towing, especially when slowing down or stopping.

[0036] A second aspect of the invention provides a trailer nose weight measuring system comprising the trailer and vehicle hitching assembly as described above, a processor and a display, wherein the processor is connected to the device suitable for measuring strain and is programmed to receive signals from the device suitable for measuring strain and output the nose weight of the trailer to the display. The device suitable for measuring strain may be connected to the processor via a wired connection. Alternatively, the device suitable for measuring strain may be connected to the processor via a transmitter connected to the device suitable for measuring strain and a corresponding receiver connected to the processor. The processor may be connected to the display via a wired connection. Alternatively, the processor may be connected to the display via a transmitter connected to the processor and a corresponding receiver connected to the display. The display may provide at least one of visual and audio feedback in dependence on the signals from the device suitable for measuring strain. In this way, the measurement provided by the device suitable for measuring strain can be used to display the nose weight of the trailer to the user. As such, this is an easy, cost effective and accurate method of allowing users to follow the relevant regulations and maintain their vehicle's safety. A third aspect of the invention provides a trailer and vehicle hitching assembly comprising a tongue portion for to a body of one of the trailer or the vehicle, a hitch portion for removably securing the trailer and vehicle hitching assembly to the other of the trailer or the vehicle, a connecting portion arranged between the tongue portion and the hitch portion, and a device suitable for measuring strain, wherein the device suitable for measuring strain is affixed to a wall of the connecting portion.

[0037] A fourth aspect of the invention provides a trailer and vehicle hitching assembly comprising : a coupling body for mounting to a body of one of the trailer or the vehicle; a hitch portion including a coupling head for removably hitching the trailer and vehicle hitching assembly to the other of the trailer or the vehicle, a tubular connecting portion arranged between the coupling body and the coupling head; and a device suitable for measuring strain.

[0038] The device suitable for measuring strain may be affixed to the inner wall of the tubular connecting portion such that an axis of the device suitable for measuring strain is aligned with a sagittal plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle. This sagittal plane may be aligned with the central longitudinal axis of the tubular connecting component when the coupling body is mounted to the body of said one of the trailer or the vehicle.

[0039] The device suitable for measuring strain may be affixed to the inner wall of the tubular connecting portion.

[0040] The trailer and vehicle hitching assembly may further comprise a second device suitable for measuring strain affixed to a wall of the tubular connecting portion. This second device suitable for measuring strain may be affixed to a wall of the tubular connecting portion opposite the first device suitable for measuring strain. Optionally, the axes of both the first and second devices suitable for measuring strain are aligned with a sagittal plane of the vehicle or trailer, said sagittal plane itself being aligned with the central longitudinal axis of the tubular connecting component. In some embodiments, the trailer and hitching vehicle assembly may include two devices suitable for measuring strain : a first affixed to a lowermost part of the inner wall of the tubular connecting component (at the "6 o'clock position"), and a second affixed to an uppermost part of the inner wall of the tubular connecting component (at the 12 o'clock position"). The first and second devices may both be positioned at substantially the same longitudinal position along the tubular connecting component. Optionally, the trailer and vehicle hitching assembly includes four devices suitable for measuring strain, each mounted to an inner wall of the tubular connecting portion, the devices being equally angularly spaced around the inner wall of the tubular connecting portion. Optionally, the axes of all four of the first, second, third and fourth devices suitable for measuring strain are aligned with the sagittal plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle, said sagittal plane being aligned with a central longitudinal axis of the tubular connecting component when the coupling body is mounted to the body of said one of the vehicle or the trailer. Optionally, the axes of both the third and fourth devices suitable for measuring strain are aligned with a transverse plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle, said transverse plane being aligned with a central longitudinal axis of the tubular connecting component. Accordingly, in some embodiments, the trailer and hitching vehicle assembly may include four devices suitable for measuring strain: a first affixed to a lowermost part of the inner wall of the tubular connecting component (at the "6 o'clock position"), a second affixed to an uppermost part of the inner wall of the tubular connecting component (at the 12 o'clock position"), a third affixed to a part of the inner wall of the tubular connecting component located 90 degrees counterclockwise from the lowermost part (at the 9 o'clock position’), and a fourth affixed to a part of the inner wall of the tubular connecting component located 90 degrees clockwise from the lowermost part (at the ’3 o'clock position’). All four devices suitable for measuring strain may be positioned at substantially the same longitudinal position along the tubular connecting component.

[0041] A fifth aspect of the invention provides a trailer and vehicle hitching assembly comprising: a coupling body for mounting to a body of one of the trailer or the vehicle; a hitch portion including a coupling head for removably hitching the trailer and vehicle hitching assembly to the other of the trailer or the vehicle, a tubular connecting portion arranged between the coupling body and the coupling head; and a device suitable for measuring strain, wherein an axis of the device suitable for measuring strain is substantially aligned with a longitudinal axis of the tubular connecting portion and wherein the device suitable for measuring strain is affixed to a part of a wall of the tubular connecting portion at which bending strain due to a static load of the trailer at the coupling head is at a maximum.

[0042] The tubular connecting portion may be hollow thereby forming an inner wall. The device suitable for measuring strain may be affixed to an inner wall of the tubular connecting portion. The tubular connecting portion may lie on a vertical plane bisecting the trailer in a longitudinal direction, the device suitable for measuring strain being substantially parallel with the vertical plane. The device suitable for measuring strain may further have an axis, for example, a longitudinal axis, this axis may be substantially coincident to the vertical plane. The axis of the device suitable for measuring strain may be aligned with a longitudinal axis of the tubular connecting component. Optionally, the axis of the device suitable for measuring strain is aligned with a central longitudinal axis of the tubular connecting component along a vertical plane when the trailer and vehicle hitching assembly is oriented for normal use in towing trailers. Optionally, the device suitable for measuring strain is affixed at a lowermost part of the inner surface, or inner wall, of the tubular connecting component. Such a positioning of the device may be referred to as the "6 o'clock position". Alternatively, the device suitable for measuring strain is affixed at an uppermost part of the inner surface, or inner wall, of the tubular connecting component. Such a positioning of the device may be referred to as the "12 o'clock position".

[0043] The trailer and vehicle hitching assembly may further comprise a second device suitable for measuring strain affixed to a wall of the tubular connecting portion. This second device suitable for measuring strain may be affixed to a wall of the tubular connecting portion opposite the first device suitable for measuring strain. This second device suitable for measuring strain adds redundancy to the system, improving reliability, whilst increasing accuracy by allowing for comparison of measurements. Optionally, the axes of both the first and second devices suitable for measuring strain are aligned with a sagittal plane of the vehicle or trailer, said sagittal plane being aligned with the central longitudinal axis of the tubular connecting component. In some embodiments, the trailer and hitching vehicle assembly may include two devices suitable for measuring strain: a first affixed to a lowermost part of the inner wall of the tubular connecting component (at the "6 o'clock position"), and a second affixed to an uppermost part of the inner wall of the tubular connecting component (at the 12 o'clock position"). The first and second devices may both be positioned at substantially the same longitudinal position along the tubular connecting component. In this setup, the strain measuring devices placed at the 12 o'clock and 6 o'clock positions along the longitudinal axis of the tube can be used to calculate the static load by comparing the strain measurements. When the static downward load from the weight of the trailer is applied to the tubular component the load creates a bending moment. This bending moment causes the tubular connecting component to experience compression on one side and tension on the opposite side. For instance, one strain measuring device will measure strain corresponding to tension and one strain measuring device will measure compression. The difference in the strain readings between these two positions reflects the bending deformation caused by the static load which is proportional to the static load applied at the coupling point.

[0044] Optionally, the trailer and vehicle hitching assembly includes four devices suitable for measuring strain, each mounted to an inner wall of the tubular connecting portion, the devices being equally angularly spaced around the inner wall of the tubular connecting portion. Optionally, the axes of all four of the first, second, third and fourth devices suitable for measuring strain are aligned with the sagittal plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle, said sagittal plane being aligned with a central longitudinal axis of the tubular connecting component. Optionally, the axes of both the third and fourth devices suitable for measuring strain are aligned with a transverse plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle, said transverse plane being aligned with a central longitudinal axis of the tubular connecting component. Accordingly, in some embodiments, the trailer and hitching vehicle assembly may include four devices suitable for measuring strain: a first affixed to a lowermost part of the inner wall of the tubular connecting component (at the "6 o'clock position"), a second affixed to an uppermost part of the inner wall of the tubular connecting component (at the 12 o'clock position"), a third affixed to a part of the inner wall of the tubular connecting component located 90 degrees counterclockwise from the lowermost part (at the 9 o'clock position’), and a fourth affixed to a part of the inner wall of the tubular connecting component located 90 degrees clockwise from the lowermost part (at the ’3 o'clock position’). All four devices suitable for measuring strain may be positioned at substantially the same longitudinal position along the tubular connecting component.

[0045] Any of the arrangements described above, with one or two strain measuring devices affixed at the 12 o'clock or 6 o'clock positions, or four strain measuring devices affixed at the 12 o'clock, 6 o'clock, 3 o'clock and 9 o'clock positions, may equally be applied to an arrangement in which the strain gauges, or strain measuring devices, are affixed to the outer wall of the tubular connecting component.

[0046] The, or each, device suitable for measuring strain, or strain measuring device, may be located in a mounting component. The mounting component may be affixed to an inner wall of the tubular connecting portion.

[0047] The, or each, device suitable for measuring strain may be a strain gauge. The, or each, strain gauge may be a thin film strain gauge. The tubular connecting portion may have one of a square, rectangular, ovoidal, or circular cross-sectional shape. The internal space formed by the hollow body of the tubular connecting portion may have substantially the same cross-sectional shape as the tubular connection portion. This allows for a greater accuracy of strain measurement.

[0048] Optionally, the coupling body is configured to be mounted to a tongue portion of a trailer. This tongue portion may form part of the trailer chassis, or frame.

[0049] The device suitable for measuring strain may be affixed to the inner wall of the connecting portion via one of welding or adhesives. These methods of affixing the device suitable for measuring strain to the inner wall provide the necessary secure attachment required for accurate strain measurements in the hitching assembly.

[0050] The mounting component may have at least one surface shaped to conform with the wall of the tubular connecting portion. The use of a mounting component allows for improved manufacturing, as the device suitable for measuring strain can be protected until fitted and more easily and accurately positioned on the connecting portion, whilst still providing the secure connection required for accurate measurements.

[0051] A sixth aspect of the invention provides a trailer comprising the trailer and vehicle hitching assembly or the trailer nose weight measuring system as described in accordance with any of the first, second, third or fourth aspects of the invention, as described above.

[0052] Brief Description of the Drawings

[0053] Embodiments will now be described, by way of example only, with reference to the accompanying figures in which:

[0054] FIGURE 1 is a side view of a trailer and vehicle coupled by a system according to the prior art;

[0055] FIGURE 2 is a side view of the system of Figure 1;

[0056] FIGURE 3 is a perspective view of a system according to a first embodiment of the present invention;

[0057] FIGURE 4 is a schematic side view of the system of Figure 3; FIGURE 5 is a perspective view of a part of the system of Figure 3;

[0058] FIGURE 6 is a schematic section end view of the system of Figure 3;

[0059] FIGURE 7 is an exploded perspective view of a device according to a second embodiment of the present invention;

[0060] FIGURE 8 is a schematic section end view of the system of Figure 7;

[0061] FIGURE 9 is a top view of a strain gauge carrier according to the first and second embodiments of the invention;

[0062] FIGURE 10 is an end view of the carrier of Figure 9; and

[0063] FIGURES 11 and 12 are schematic section end view of alternative arrangements for measuring the nose weight in the system of Figure 3.

[0064] Detailed of Embodiments

[0065] With reference to Figures 3 to 6, below is described a system 100 according to a first embodiment of the present invention. System 100 comprises strain gauge 110 affixed to a draw tube 120.

[0066] Strain gauge 110 is a thin film strain gauge, but other types of strain gauge are also envisaged. Furthermore, other types of measuring devices could also be used, as long as they are capable of measuring strain. The strain gauge 110 is formed along a central longitudinal axis A-A.

[0067] Draw tube 120 (as shown in Figure 5) has a cylindrical shape formed along a central longitudinal axis Z-Z and, as in the prior art system 10, connects the coupling body 25 and the coupling head 27. Other cross-sectional shapes of draw tube 120 are also envisaged (such as a square or rectangle), as long as the draw tube 120 is strong enough to withstand the loads placed upon it in use and to meet the relevant legal requirements. Draw tube 120 has a first end 122 and a second end 124, the first end 122 having a pair of bores 126 (the function of which is described below). In Figure 5, the bores 126 extend approximately along a transverse plane of the draw tube 120. However, it will be understood that the position and orientation of the bores 126 is not limited. For instance, in some embodiments the bores 126 may extend along a sagittal plane of the draw tube 120, or they may extend along a plane which is oblique to the sagittal plane. Alternatively still, the bores 126 may include a combination of bores 126 oriented along different directions. The draw tube 120 further has an outer surface 127 and is hollow (for weight saving and other benefits described below), forming an inner surface 128. The outer and inner surfaces 127, 128 have the same cross-sectional shape, taken as seen in Figure 6 along a vertical axis Y-Y and a transverse axis X-X of draw tube 120. However, different surface cross-sections and solid formulations are also envisaged. Draw tube 120 can be the draw tube 26 of the prior art system 10, allowing for easy modification of existing systems.

[0068] As seen in Figures 4 to 6, the strain gauge 110 is affixed to the inner surface of the draw tube 120. This provides protection to the strain gauge 110 from stone strikes and other sources of potential damage. The strain gauge 110 is affixed such that the strain gauge's axis A-A is parallel to the draw tube's longitudinal axis Z-Z and further that, when the draw tube 120 is part of the coupling 24, the strain gauge 110 is at the lowermost part of the inner surface 128 (i.e., is coincident with the vertical axis Y-Y). This location allows for a more accurate and straightforward calculation of trailer nose weight, as is discussed in further detail below. However, other locations for affixing the strain gauge 110 around the draw tube 120 are envisaged, either on the outer or inner surface 127, 128, such as locations coincident with the transverse axis X-X. These potential locations are shown in dashed lines in Figures 4 and 6, Figure 6 being an end section view taken on a cut through the draw tube 120. Meanwhile, for clarity, Figure 5 shows a bottom view of the draw tube 120 with the wire 112 connected to the strain gauge 110 in the anticipated position, with some of the other envisaged positions also shown.

[0069] The strain gauge 110 is attached by adhesive, as this provides a strong, durable, and long- lasting attachment (to ensure the accuracy of the measurements) without damaging the strain gauge or the draw tube 120. However, other attachment methods (such as welding) are also envisaged. Accordingly, there is no requirement for alteration of the draw tube 120 and existing draw tubes 120 can be retrofit to provide the inventive system.

[0070] When being assembled (as shown in Figures 3 and 4), first end 122 of the draw tube 120 is slid through a corresponding hole 25h in coupling body 25, such that the second end 124 is proximate to the coupling body 25 and the draw tube 120 extends away from the trailer tongue 22. Coupling head 27 is then secured to the first end 122 via bolts through bores 126. Other securement methods (such as welding) are also envisaged. The strain gauge 110 is positioned in the draw tube 120 before assembly. In the illustrated embodiment, (as seen in Figure 4), the strain gauge 110 is located in the middle of the points where the coupling body 25 and coupling head 27 extend over the draw tube 120. However, in other embodiments, the strain gauge 110 is positioned towards the coupling body 25, and in particular, near or at the end of the draw tube 120 adjacent the coupling body 25. Indeed, in some embodiments, the strain gauge 110 may be positioned at about the same longitudinal location as the hole 25c in the illustrated embodiment. However, it will be understood that the position of the hole 25c itself is not limited and will vary depending on the particular approach used for mounting the coupling body 25. The position of the strain gauge 110 is therefore not dependent on the position of the hole 25c.

[0071] Strain gauge 110 is connected via a wire 112 to a processor (not shown). Wireless transmission of the signals from the strain gauge 110 to the processor is also envisaged. The processor then translates the raw data from the strain gauge 110 into a trailer nose weight reading and outputs said reading. The output may be to any (or a combination) of a visual display, an audio warning sound (for if the weight exceeds a set limit) or any other feedback device suitable for informing the user of the trailer nose weight.

[0072] The location of the strain gauge 110 allows for a straightforward calculation of the trailer nose weight, meaning the computational power required is less and the opportunity for errors (from operations such as the rounding of figures) is reduced, all whilst only using a single strain gauge 110. This makes the system 100 cheaper, more accurate and less computationally intensive than previous systems. It has also been found that placing the strain gauge 110 on the lower inner surface 128 of draw tube 110 (as seen in Figures 4 to 6) can produce better results, as some of the strain gauges 110 used can be more accurate when reading tension measurements.

[0073] It is also alternatively envisaged that the system 100 could utilise multiple strain gauges 110, located in various of the locations mentioned above. The use of multiple strain gauges 110 does add computational complexity, but allows for the comparison / checking of measurements against each other and to to reduce the likelihood of total system failure. When using multiple strain gauges 110, it is useful to affix them in pairs on either of the outer or inner surfaces 127, 128 of the draw tube 120, with each strain gauge 110 opposite the other. This allows for more useful and easier processingof the data they produce.

[0074] System 100 as described above is for an EU style of trailer and vehicle hitching arrangement. These couplings can be either braked or unbraked. However, legislation requires that trailers that weigh over 750 kilograms require brakes. The lighter trailers which use a non-braked coupling system essentially provide a rigid connection between the trailer and the towing vehicle and may be described as a rigid hitch. On the other hand, heavier trailers equipped with a braked coupling system typically incorporate a movable hitch, which features an overrun mechanism. The overrun mechanism is a type of coupling that allows the trailer to move slightly during towing, especially when slowing down or stopping. This means when the towing vehicle begins to slow down, the trailer can momentarily continue moving forward at its original speed before the brakes are activated. This setup contrasts with the rigid hitch of unbraked couplings, where there is no such relative movement between the trailer and the vehicle.

[0075] Those skilled in the art will appreciate that the principles of the invention apply equally to a US style of trailer and vehicle hitching arrangement. This is exemplified in system 200 according to a second embodiment of the present invention, which is described below with reference to Figures 7 and 8.

[0076] In this system 200, a subframe 210 is mounted to the rear of the vehicle 30, the subframe 210 comprising a pair of mounting points 212 (for affixing the subframe 210 to the vehicle 30) with a crossbeam 214 extending therebetween. From the centre of this crossbeam 214 there extends a receiving tube 216 with bores 218 therethrough, the receiving tube 216 being hollow and ending in an open aperture 217.

[0077] The system 200 also comprises a removeable tow hitch 220 with a first end 222 and a second end 224. The first end 222 has a ball 226 as per the ball 36 in the prior art system 10. However, other known attachment methods are also suitable, such as a ring and pin type hitch. The second end 224 has an elongate member 228 with bores 229 arranged therethrough proximate to the second end 224. The elongate member 228 is hollow, and sized and shaped such that it can be inserted into the receiving tube 216 via aperture 217 with minimal clearance and secured via bolts through aligned bores 218, 229. In this way, a removable tow hitch 220 is provided.

[0078] In this embodiment, as seen in Figures 7 and 8, the strain gauge 110 is located on the elongate member 228, on an inner surface 228a. When assembled, the strain gauge 110 is not located on a part of the elongate member 228 covered by the receiving tube 216. As with the first embodiment described above, mounting the strain gauge 110 internally increases the protection to, and accuracy of, the strain gauge 110, whilst decreasing the computational requirement for producing the trailer nose weight measurement. However, similar positions on the elongate member 228 can be used for affixing the strain gauge 110, including those as are envisaged for the draw tube 120 of the first embodiment, as can the use of multiple strain gauges 110. As with the first embodiment, other potential strain gauge locations are shown in dashed lines in Figures 7 and 8, including those on an outer surface 228b of elongate member 228 (of which Figure 8 is a cut though end section view). The same strain gauge 110 and attachment methods can be used in this second embodiment as are used in the first embodiment described above.

[0079] This second embodiment allows for the same accurate, cheap and computationally efficient trailer nose weight measurement as in the first embodiment, but suitable for towing systems that do not include a draw bar 120 (as in the US, for example).

[0080] In both the first and second embodiment, the strain gauge 110 is mounted on a carrier 300, as seen in Figures 9 and 10 and described below.

[0081] The carrier 300 comprises a substantially rectangular cuboidal body 310 shaped (i.e., large enough) to fully accommodate the strain gauge 110. The body 310 has a flat first side 312 opposite a second side 314. The second side 314 has a recess 320 shaped to fit the strain gauge 110 as further described below. The recess 320 has an open end 330 to allow for easy connection of the strain gauge 110 to the wire 112. The second side 314 may also have chamfered longitudinal edges 340, the function of which is explained below.

[0082] The recess 320 is formed of, from the open end 330 in order as seen in Figure 9, a connector recess 322, a channel 324, a solder recess 326 and a strain gauge recess 328. The connector recess 322 is deep enough to house the wire 112 surrounded by insulation, the insulation allowing the wire 112 to be adhered to the carrier 300. The channel 324 holds the wire 112 as is deep enough so the wire 112 does not contact the draw tube 120. The solder recess 326 is deep enough to hold a soldered connection between wire 112 and strain gauge 110 without the solder touching the draw tube 120, which would short circuit the system. Finally, strain gauge recess 328 holds the strain gauge 110 itself and is shallower than the thickness of the strain gauge 110, for reasons that will be discussed below.

[0083] The carrier 300 is made of a single piece of plastic for easy manufacture and attachment to the draw tube 120 or elongate member 228 via adhesive, although other materials (such as any non-reactive metals) are envisaged.

[0084] When using the carrier 300, it is arranged on / in the draw tube 120 or elongate member 228 such that the second side 314 is facing the surface to which the strain gauge 110 is attached, to ensure the strain gauge 110 is flat against said surface to maintain the accuracy of the measurements. In the cases where the surface in question is curved, the chamfered edges 340 of the carrier 300 allow this secure positioning despite the curvature.

[0085] The strain gauge 110 is adhered to the carrier 110 by a flexible glue, so the carrier 110 does not influence the strain gauge's 110 readings. The depth of the strain gauge recess 328 ensures the strain gauge 110 is properly located on and secured to the required surface. As such, the carrier 300 provides protection to the strain gauge 110 prior to and during the assembly process and helps to ensure a secure and accurate attachment to the necessary surface, whilst not affecting the measurements taken by the strain gauge 110. The carrier 300 also increases protection from factors such as stone strike and road debris when the strain gauge 110 is fitted to an external surface. However, systems not using the carrier 300 are also envisaged. For example, the surfaces 127, 128, 228a, 228b where the strain gauge 110 may be fitted could be etched to provide a location for the strain gauge 110 to sit.

[0086] An alternative arrangement of strain gauges for measuring the nose weight according to the invention is shown in Figure 11. Although Figure 11 depicts the alternative arrangement in the system 100 of Figure 3, it will be understood that this arrangement of strain gauges could equally be applied in elongate member 228 of the system 200 of the second embodiment. In Figure 11, it can be seen that strain gauges 110 are affixed to an inner wall of the draw tube 120 such that both strain gauges' axes A-A are parallel to the draw tube's longitudinal axis Z-Z and further such that, when the draw tube 120 is part of the coupling 24, a first one of the strain gauges 110 is at the lowermost part of the inner surface 128 and a second one of the strain gauges 110 is at the uppermost part of the inner surface 129. As such, both strain gauges 110 are coincident with the vertical axis Y- Y. According to this arrangement, the first one of the strain gauges is located at the part of the inner wall 128 subject to maximum tension and the second one of the strain gauges 110 is located at the part of the inner wall 128 subject to maximum compression. This provides for a more accurate measurement of the nose weight by comparing the readings from both gauges 110.

[0087] A further alternative arrangement of strain gauges for measuring the nose weight according to the invention is shown in Figure 12. Although Figure 12 depicts the alternative arrangement in the system 100 of Figure 3, it will be understood that this arrangement of strain gauges could equally be applied in elongate member 228 of the system 200 of the second embodiment. In Figure 12, it can be seen that all four strain gauges 110 are affixed to an inner wall of the draw tube 120 such that the axes A-A are parallel to the draw tube's longitudinal axis Z-Z. The strain gauges 120 are affixed such that, when the draw tube 120 is part of the coupling 24, a first one of the strain gauges 110 is at the lowermost part of the inner surface 128, a second one of the strain gauges 110 is at the uppermost part of the inner surface 129 and the third and fourth strain gauges are arranged on the inner wall between the first and second strain gauges, such that the four strain gauges 110 are equally angularly spaced around the inner surface 128 of the draw tube 120. As such, two strain gauges 110 are coincident with the vertical axis Y-Y and two are coincident with the transverse axis X-X. This arrangement advantageously enables the more accurate calculation, not only of the nose weight (or S force), but also of the dynamic force (or D force) transmitted through the coupling between the towing vehicle and the trailer which arise from acceleration, braking, cornering, swaying, and road surface variations. This is because the strain gauges 110 effectively capture the lateral forces (side-to-side) that occur during dynamic events like cornering or swaying.

[0088] Whilst the description of these embodiments has been with reference to a trailer 20, it should be understood that the systems 100, 200 would be suitable for any towed object (such as a caravan) using similar coupling methods.

[0089] While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. It is to be understood, therefore, that the present disclosure is not limited to the precise embodiments described, and that various other changes and modifications may be effected by one skilled in the art without departing from the scope or spirit of the disclosure. Additionally, the elements and features shown and described in connection with certain embodiments may be combined with the elements and features of certain other embodiments without departing from the scope of the present disclosure, and that such modifications and variation are also included within the scope of the present disclosure. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Thus, the scope of the embodiments should be determined by the appended claims and their legal equivalents, rather than by the examples given.

[0090] Various examples of aspects of the subject technology are described as numbered clauses (1, 2, 3, etc.) for convenience. These are provided as examples and do not limit the subject technology. It is noted that any of the dependent clauses may be combined in any combination, and placed into a respective independent clause, e.g., clause 1 or clause 5. The other clauses can be presented in a similar manner. Clause 1. A trailer and vehicle hitching assembly comprising a tongue portion for to a body of one of the trailer or the vehicle, a hitch portion for selectably securing the trailer and vehicle hitching assembly to the other of the trailer or the vehicle, a connecting portion arranged between the tongue portion and the hitch portion, and a device suitable for measuring strain, wherein the device suitable for measuring strain is affixed to a wall of the connecting portion.

[0091] Clause 2. The trailer and vehicle hitching assembly according to Clause 1, wherein the tongue portion is for affixing to a body of the trailer and the hitch portion is for selectably securing the trailer and vehicle assembly to the vehicle.

[0092] Clause 3. The trailer and vehicle hitching assembly according to Clause 1, wherein the tongue portion is for affixing to a body of the vehicle and the hitch portion is for selectably securing the trailer and vehicle assembly to the trailer.

[0093] Clause 4. The trailer and vehicle hitching assembly according to any of the preceding Clauses, wherein the device suitable for measuring strain is affixed to an outer wall of the connecting portion.

[0094] Clause 5. The trailer and vehicle hitching assembly according to any of the preceding Clauses, wherein the connecting portion is hollow.

[0095] Clause 6. The trailer and vehicle hitching assembly according to Clause 5, wherein the device suitable for measuring strain is affixed to an inner wall of the connecting portion.

[0096] Clause 7. The trailer and vehicle hitching assembly according to any of the preceding Clauses, wherein the connecting portion has one of a square, rectangular, ovoidal, or circular cross-sectional shape.

[0097] Clause 8. The trailer and vehicle hitching assembly according to Clause 7 when dependent on Clause 5, wherein the internal space formed by the hollow tubular connecting portion has substantially the same cross-sectional shape as the connection portion.

[0098] Clause 9. The trailer and vehicle hitching assembly according to any of the preceding Clauses, wherein the device suitable for measuring strain is affixed to the wall of the connecting portion via one of welding or adhesives. Clause 10. The trailer and vehicle hitching assembly according to any of the preceding Clauses, wherein the device suitable for measuring strain is located in a mounting component, the mounting component being affixed to the wall of the connecting portion Clause 11. The trailer and vehicle hitching assembly according to Clause 10, the mounting component having at least one surface shaped to conform with the wall of the connecting portion.

[0099] Clause 12. The trailer and vehicle hitching assembly according to any of the preceding Clauses, wherein the connecting portion lies on a vertical plane bisecting the trailer in a longitudinal direction, the device suitable for measuring strain being substantially parallel with the vertical plane.

[0100] Clause 13. The trailer and vehicle hitching assembly according to Clause 12, wherein the device suitable for measuring strain has a longitudinal axis, said axis being substantially coincident to the vertical plane.

[0101] Clause 14. The trailer and vehicle hitching assembly according to any of the preceding Clauses, further comprising a second device suitable for measuring strain affixed to a wall of the connecting portion.

[0102] Clause 15. The trailer and vehicle hitching assembly according to claim 14, wherein the second device suitable for measuring strain is affixed to a wall of the connecting portion opposite the first device suitable for measuring strain.

[0103] Clause 16. The trailer and vehicle hitching assembly according to any of the preceding Clauses, wherein the device suitable for measuring strain is a strain gauge.

[0104] Clause 17. The trailer and vehicle hitching assembly according to Clause 16, wherein the strain gauge is a thin film strain gauge.

[0105] Clause 18. A trailer nose weight measuring system comprising the trailer and vehicle hitching assembly according to any of the preceding Clauses, a processor and a display, wherein the processor is connected to the device suitable for measuring strain and is programmed to receive signals from the device suitable for measuring strain and output the nose weight of the trailer to the display. Clause 19. The trailer nose weight measuring system according to Clause 18, wherein the device suitable for measuring strain is connected to the processor via a wired connection.

[0106] Clause 20. The trailer nose weight measuring system according to Clause 18, wherein the device suitable for measuring strain is connected to the processor via a transmitter connected to the device suitable for measuring strain and a corresponding receiver connected to the processor.

[0107] Clause 21. The trailer nose weight measuring system according to any of Clauses 18 to 20, wherein the processor is connected to the display via a wired connection.

[0108] Clause 22. The trailer nose weight measuring system according to any of Clauses 18 to 20, wherein the processor is connected to the display via a transmitter connected to the processor and a corresponding receiver connected to the display.

[0109] Clause 23. The trailer nose weight measuring system according to any of Clauses 18 to 22, wherein the display provides at least one of visual and audio feedback in dependence on the signals from the device suitable for measuring strain.

[0110] Clause 24. A trailer comprising the trailer and vehicle hitching assembly according to any of Clauses 1 to 17 or the trailer nose weight measuring system of any of Clauses 18

Claims

Claims1. A trailer and vehicle hitching assembly comprising : a coupling body for mounting to a body of one of the trailer or the vehicle; a hitch portion including a coupling head for removably hitching the trailer and vehicle hitching assembly to the other of the trailer or the vehicle, a tubular connecting portion arranged between the coupling body and the coupling head, the trailer and vehicle hitching assembly being configured such that a central longitudinal axis of the tubular connecting portion is aligned with a sagittal plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle, the tubular connecting portion being hollow thereby forming an inner wall; and a device suitable for measuring strain affixed to the inner wall of the tubular connecting portion, wherein an axis of the device suitable for measuring strain is aligned with the sagittal plane of the one of the trailer or the vehicle when the coupling body is mounted to the body of said one of the trailer or the vehicle.

2. The trailer and vehicle hitching assembly according to claim 1, wherein the coupling body is configured to be affixed to a body of the trailer and the hitch portion is for removably securing the trailer and vehicle assembly to the vehicle.

3. The trailer and vehicle hitching assembly according to claim 2, wherein the coupling head comprises a downward facing recess.

4. The trailer and vehicle hitching assembly according to claim 1, wherein the coupling body is configured to be affixed to a body of the vehicle and the hitch portion is for removably securing the trailer and vehicle assembly to the trailer.

5. The trailer and vehicle hitching assembly according to claim 4, wherein the coupling head comprises a tow ball or a tow pin.

6. The trailer and vehicle hitching assembly according to any of the preceding claims, wherein the tubular connecting portion has one of a square, rectangular, ovoidal, or circular cross-sectional shape.

7. The trailer and vehicle hitching assembly according to claim 6, wherein the internal space formed by the tubular connecting portion has substantially the same cross-sectional shape as the tubular connecting portion.

8. The trailer and vehicle hitching assembly according to any of the preceding claims, wherein the device suitable for measuring strain is affixed to the inner wall of the tubular connecting portion via one of welding or adhesives.

9. The trailer and vehicle hitching assembly according to any of the preceding claims, wherein the device suitable for measuring strain is located in a mounting component, the mounting component being affixed to the inner wall of the tubular connecting portion.

10. The trailer and vehicle hitching assembly according to claim 9, the mounting component having at least one surface shaped to conform with the wall of the connecting portion.

11. The trailer and vehicle hitching assembly according to any of the preceding claims, wherein the tubular connecting portion lies on a vertical plane bisecting the trailer in a longitudinal direction, the device suitable for measuring strain being substantially parallel with the vertical plane.

12. The trailer and vehicle hitching assembly according to claim 11, wherein the device suitable for measuring strain has a longitudinal axis, said axis being substantially coincident to the vertical plane.

13. The trailer and vehicle hitching assembly according to any of the preceding claims, further comprising a second device suitable for measuring strain affixed to a wall of the connecting portion.

14. The trailer and vehicle hitching assembly according to claim 13, wherein the second device suitable for measuring strain is affixed to a wall of the connecting portion opposite the first device suitable for measuring strain.

15. The trailer and vehicle hitching assembly according to any of the preceding claims, wherein the or each device suitable for measuring strain is a strain gauge.

16. The trailer and vehicle hitching assembly according to claim 15, wherein the or each strain gauge is a thin film strain gauge.

17. A trailer nose weight measuring system comprising the trailer and vehicle hitching assembly according to any of the preceding claims, a processor and a display, wherein theprocessor is connected to the device suitable for measuring strain and is programmed to receive signals from the device suitable for measuring strain and output a nose weight of the trailer to the display.

18. The trailer nose weight measuring system according to claim 17, wherein the device suitable for measuring strain is connected to the processor via a wired connection.

19. The trailer nose weight measuring system according to claim 17, wherein the device suitable for measuring strain is connected to the processor via a transmitter connected to the device suitable for measuring strain and a corresponding receiver connected to the processor.

20. The trailer nose weight measuring system according to any of claims 17 to 19, wherein the processor is connected to the display via a wired connection.

21. The trailer nose weight measuring system according to any of claims 17 to 20, wherein the processor is connected to the display via a transmitter connected to the processor and a corresponding receiver connected to the display.

22. The trailer nose weight measuring system according to any of claims 17 to 21, wherein the display provides at least one of visual and audio feedback in dependence on the signals from the device suitable for measuring strain.

23. A trailer comprising the trailer and vehicle hitching assembly according to any of claims 1 to 16 or the trailer nose weight measuring system of any of claims 17 to 22.