FIELD OF THE INVENTION

[0001] The present invention relates to a force measuring device incorporated into a tow ball or tow pin.

BACKGROUND TO THE INVENTION

[0002] When vehicles are engaged in towing a trailer unit, the most common type of connection used between the towing vehicle and trailer is a ball-hitch or ball-hitch and drawbar coupling. The ball-hitch fitting is attached to either a rear bumper fitting or a horizontally extending drawbar located on the rear of the so-equipped towing vehicle. Recently however tow pins have also become popular.

[0003] The typical tow ball has a spherical shape at the upper end and a threaded rod with a nut, or a bolt that threads into the lower end. The threaded nut or bolt is used to secure the tow ball to the towing drawbar or bumper fitting of the towing vehicle. The drawbar on so-equipped vehicles is further inserted into a drawbar receiver and held in place by means of a retaining pin that may be rounded or rectangular in shape.

[0004] The tow ball fitting couples to a trailer ball-receiver or coupler fitting located on the forward-most portion of the trailer's frame or "tongue" of the trailer. It is this ball & socket connection that allows for the trailer unit to rotate and pivot freely with respect to the tow ball and towing vehicle.

[0005] Once the tow ball has been coupled to the socket on the trailer, energies and forces are then transmitted between the towing vehicle and trailer. For example, the static downward force of the trailer's tongue referred to as "tongue weight" would be transferred to the ball hitch and drawbar. Acceleration, deceleration and lateral forces will also be transferred to the ball-hitch drawbar mechanism acceleration creating a pulling force between a towing vehicle and a towed vehicle and deceleration creating a compressive force between the vehicles.

[0006] Tongue weight is one important factor in keeping the coupler securely seated on the ball hitch and influencing whether the trailer will be towed in a balanced and stable manner. Improper tongue weight contributes significantly to unstable and unsafe towing characteristics in both the trailered unit and towing vehicle. For example, too much tongue weight will cause the towed vehicle to pitch downward excessively during deceleration. Excessive tongue weight also contributes to excessive wear and tear on braking and transmission components. Too little tongue weight may lead to accidental separation of the ball hitch coupler connection and tends to induce pitch and yaw in the towed and towing vehicles. Manufacturers of vehicles will provide recommended tongue-weight ranges for their respective vehicles when engaged in towing. Tongue and force loads are the key elements a vehicle manufacturer is considering when determining the maximum towing capacity for any particular vehicle.

[0007] The major side effect of too little tow ball weight is the extremely dangerous "trailer sway" condition. Most accidents and fatalities with trailers and caravans are due to this situation occurring.

[0008] There is therefore a need to provide a tow ball that can measure the force or the weight on the tow ball so that the driver of the vehicle can determine if the weight falls within the manufacturer's specifications. If not the driver can redistribute the load on the trailer to ensure that the weight on the tow ball is appropriate.

SUMMARY OF THE INVENTION

[0009] In a first aspect the invention comprises an apparatus comprising:

a tow ball attached to a vehicle and configured to receive a tongue of a trailer and adapted to sense a force exerted on it;

a sensor integral within the tow ball and adapted to output a signal substantially corresponding to the force.

[0010] In preference the tow ball includes a top part and a bottom part, wherein the top part is adapted to move with respect to the bottom half as part of the sensor.

[0011] Preferably the sensor comprises a hydraulic chamber.

[0012] Preferably the sensor comprises a load cell.

[0013] In preference the output signal is made available through remote

communication.

[0014] In preference a display is coupled to the output signal, the display being operative to produce an indication of the force exerted on the trailer tow ball.

[0015] In a further form of the invention there is provided a trailer tow ball having an integrated sensor operative to detect a downward force imparted on a trailer hitch to which the trailer tow ball is attached while a trailer is coupled to the trailer tow ball and to convey the downward force to a display mechanism.

[0016] In preference the apparatus is adapted to receive information about the vehicle and the trailer and alert the user if the force on the tow ball is outside of predefined parameters.

[0017] It should be noted that any one of the aspects mentioned above may include any of the features of any of the other aspects mentioned above and may include any of the features of any of the embodiments described below as appropriate.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way. The Detailed Description will make reference to a number of drawings as follows.

[0019] Figure 1 is a perspective front view of the apparatus embodying the invention and including a transmitter system for transmitting collected data to an external device;

[0020] Figure 2 is a perspective front view of the apparatus embodying the invention providing analogue information to an external device;

[0021] Figure 3 is a schematic illustration of the device where the device uses a hydraulic system; and

[0022] Figure 4 is an alternate tow pin arrangement.

DETAILED DESCRIPTION OF THE INVENTION

[0023] The following detailed description of the invention refers to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the following description to refer to the same and like parts. Dimensions of certain parts shown in the drawings may have been modified and/or exaggerated for the purposes of clarity or illustration.

[0024] The invention is a tow ball normally attached to a vehicle for the purpose of coupling to a trailer or caravan. This tow ball differs from the standard or normal type in that the actual tow ball itself has an integral measuring device to indicate the downwards force onto the tow ball exerted by the equipment being towed. The measuring system is typically embedded within the body of the tow ball but in some cases could be an external attachment.

[0025] Instead of a tow ball the arrangement could equally well apply to a tow pin that is becoming more commonly used in the towing of caravans and the like.

[0026] The method of measurement can vary between models being either by the compression of hydraulic fluid which is transferred to a mechanical gauge or to a transducer which then can be viewed as a force. This force can be viewed on an electronic readout or be transferred via Bluetooth or other similar system to be viewed on a smart device "app".

A secondary measuring method incorporates a load cell strain gauge system with appropriate electronic measurement and display.

[0027] The invention can be incorporated into to varying tow ball designs of which there are varying types and configurations. The tow ball is tested and certified to meet all required safety standards. The tow ball incorporates mechanical designs enabling it to be calibrated and certified using an external force calibration device.

[0028] Typically 10% of the total weight of the loaded trailer or caravan should be resting on the tow ball. So in simple terms if it weighs 2500 kg then there should be approximately 250 Kg weight on the tow ball. This ball weight can change if one loads a caravan differently when packing up for a trip or whether there are full or empty water and sullage tanks or gas bottles. If one is loading a car or machinery on a tandem trailer the ultimate positioning will change the weight on the tow ball.

[0029] Referring now to the drawings in details there is provided a force measuring device 10. This includes a tow ball that is separated into a top and bottom parts 12a and 12b whereby there is an initial gap between the two parts enabling 12a to move towards 12b under force.

[0030] Typically the top part of the tow ball 12a is of a smaller height than the bottom part 12b, such as being 1/3 to 2/3.

[0031] The tow ball is includes a flange 14 and a threaded bolt 16 whereby nut 18 screws onto the thread 16 and secures the tow ball to drawbar 20. Extending from the tow ball is a hose or data cable 21 that provides weight information. [0032] In one embodiment support 22 supports remote mount 24 that provides the weight information to a receiver/transmitter 26 where the system is digital or to remote mount 28 that provides analogue data to a gauge 30.

[0033] There are many ways that the weight on the tow ball can be measured, such as hydraulic pressure or load cells. The simplest is to use a hydraulic system that can be calibrated before it leaves the manufacturer. A typical hydraulic system is illustrated in Figure 3 where the bottom half of the tow ball 12b provides support for the top half 12a that includes cylinder engaging piston 34, whereby the pressurised fluid is fed through to a sensor 36 that can measure the exerted force. The other parts of the drawings relate to common embodiments such as bleed screws that remove air from the system when the tow ball is being calibrated during manufacture.

[0034] The arrangement can also be used on a tow pin arrangement as illustrated in Figure 4.

[0035] The reader will now appreciate the present invention which provides information as to the load weight on a tow ball or tow pin.

[0036] The present specification discussed two embodiments of how the weight on the tow ball or tow pin is measured and displayed. It is understood that it can be measured in a number of ways but for simplicity the applicant has found that using a hydraulic system is cost-effective and robust without having to change the structure of a tow ball.

[0037] The hydraulic system can provide analogue information to a gauge that can be viewed by a user who would then determine whether or not it is in the acceptable limits. Alternatively the information can be provided electronically and using remote

communication such as Bluetooth it can be transmitted to a user on an electronic device such as a phone. This information can not only be provided at the time of attaching the trailer to a vehicle but can be provided continuously when the vehicle is in motion

(obviously the tow ball would have to be provided with a power source).

[0038] Further improvements to the technology would be that the device 10 is able to accept information from a device such a mobile phone in regard to parameters that need to be taken into consideration in relation to the weight on the tow ball and provide a warning to the user if the weight distribution is inappropriate. These may include the type of towing vehicle and information of what is being towed. [00B9] Yet further improvements to this application is that an app would be available that would allow the user to access information to select the type of vehicle and the towed unit, transmit that information to the device which would then respond with a warning of the weight on the tow ball is not acceptable. Yet a further embodiment may include the tow ball system being in communication with the vehicle operating system and prevent the vehicle from being able to be drive unless the weight was appropriate or alternatively limit the speed which the vehicle may be able to travel at.

LIST OF COMPONENTS

[0040] The drawings include the following integers.

10 force measuring device

12a top part of tow ball

12b bottom part of tow ball

14 flange

16 threaded bolt

18 nut

20 drawbar

22 support

24 remote mount

26 receiver/transmitter

28 remote mount

30 gauge

32 cylinder

34 piston

36 sensor

38 tow pin

[0041] Further advantages and improvements may very well be made to the present invention without deviating from its scope. Although the invention has been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices and apparatus. Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in this field.

[0042] In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.