1 MOTORISED JOCKEY WHEEL FIELD OF THE INVENTION [0001] The present invention relates to a motorised jockey wheel for use with trailers, caravans or other motor homes, boat trailers, horse floats and any other vehicle which is towable. BACKGROUND OF THE INVENTION [0002] The following discussion of the background to the invention is intended to facilitate an understanding of the invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge as at the priority date of the application. [0003] There are many forms of towable vehicles that are towed by motorists for work or pleasure. Caravans are one form of towable vehicle that are usually used for holidaying and are towed to a holiday destination by a suitable vehicle. Most drivers are capable of towing a vehicle during forward driving but have more difficulty when driving in reverse. Caravans in particular can be quite large and therefore difficult to manoeuvre when in reverse. The difficulty of reversing a caravan is exacerbated when the caravan has to be reversed into a small or tight space. Moreover, while very small caravans can be un-hooked from the towing vehicle and pushed by hand into position, larger caravans cannot. The reversing process can take a long time and if not completed correctly, the caravan can be backed into objects or fixtures causing damage to both the caravan and the objects and fixtures. For many drivers, just the thought of having to reverse a caravan is stressful. [0004] The problem with reversing a caravan not only occurs at the holiday destination but also upon return home when the caravan is garaged or otherwise stored. Often that can be the most difficult reverse given that the space available for storage (usually a garage or carport) is usually very small and only a small amount larger than the caravan itself. <filename> 2 [0005] Other towable vehicles can cause the same difficulty as described above in relation to caravans, but caravans in particular are often towed by drivers that have limited reversing experience and often only have to reverse a caravan on holidays that might occur only once or twice a year. The present invention has therefore been developed principally in relation to use with caravans, although it is to be appreciated that the invention could have wider application to other forms of towable vehicles. [0006] Reversing assistance has been provided for caravans in the past through complex and heavy systems that attach to the undercarriage of the caravan and that drive the wheels of the caravan when required. For a single axle trailer, these systems include a pair of motors to separately drive the wheels at each end of the axle, while a dual axle caravan can include four motors to separately drive each of the four wheels. In these systems, the towing vehicle is uncoupled from the caravan and subsequent propulsion takes place through drive of the caravan wheels by the separate motors. [0007] A disadvantage of the above systems is that the wheels are permanently attached to the undercarriage of the caravan and therefore they permanently add to the weight of the caravan so that fuel economy during towing is affected as is the power available to tow the caravan. This added weight is wasteful particularly for caravan owners who only need the reversing assistance at home rather than at the destination to which the caravan is to be towed. [0008] Reversing assistance has also been provided by hand operated arrangements that attach to the drawbar of the caravan. One of these arrangements is a jockey wheel that includes a wheel and ratchet gear mounted on the axis of the wheel. A ratchet lever is operated by foot to rotate the ratchet gear and to drive the wheel. While this arrangement is very simple and relatively cheap, it is not easy to operate and movement of the caravan is very slow. [0009] Powered reversing assistance has also been provided for arrangements that connect to the drawbar of a caravan. These include arrangements in which a wheel is driven by a motor. However, the arrangements known to applicant are manually steerable and some also require a dedicated power source for the motor drive. <filename> 3 [0010] Applicant recognises the desirability to make the reversing of caravans and other towable vehicles easier and has developed the invention with that aim in mind. SUMMARY OF THE INVENTION [0011] The present invention provides a motorised jockey wheel that includes: a chassis, an upstanding post connected to the chassis for connection to a towable vehicle, first and second wheels that are spaced apart along the same axis and which are rotatable relative to each other, first and second motors coupled to respectively to the first and second wheels for driving the first and second wheels to rotate, a controller for controlling the output of the motors, wherein power to drive the first and second motors passes through the controller which adjusts the power based on an input to the controller from a remote control that is controlled by an operator of the jockey wheel, so that the speed of rotation of the first and second wheels can be varied for driving and steering the jockey wheel. [0012] A motorised jockey wheel according to the invention advantageously allows steering through manipulation of the speed of the respective first and second wheels. Thus, the operator can steer the jockey wheel by operation of the remote control and is not required to manually turn the jockey wheel as in the prior art. This means that steering the jockey wheel is less difficult. [0013] A motorised jockey wheel according to the invention also allows the operator to move away from the jockey wheel and not lose control of the jockey wheel. This is because the remote control of the jockey wheel can communicate with the jockey wheel wirelessly or it can be connected to the jockey wheel by an electrical cord of a length that allows the operator to move to either side of the caravan or other towable vehicle that the jockey wheel according to the invention is being used with. This distinguishes the present the invention from other prior art in which the operator is required to stay in close proximity to the jockey wheel in order to operate the jockey wheel, such as for steering. <filename> 4 [0014] The electrical cord can be of any suitable length and can be retractable or coiled so as to take up less room when the jockey wheel is not in use. Advantageously however, when the jockey wheel is in use, the operator can walk away from the jockey wheel as the jockey wheel is driving the caravan or other towable vehicle for a better view of the space into which the caravan or other towable vehicle is to be moved. The operator can walk away from the jockey wheel but still retain control of the jockey wheel through the connection between the remote control and the jockey wheel. The operator can thus clearly see any objects in the way of the reversing vehicle and in some cases where the electrical cord is of sufficient length, the operator can position him or herself behind the reversing vehicle so as to know exactly when to stop the vehicle. Thus, the motorised jockey wheel according to the invention can alleviate the need for a second person to be involved in the reversing of the vehicle, because the operator can move to the positions that he or she needs to be in order to properly guide the reversing vehicle into place. [0015] The electrical cord can be removable from connection with the jockey wheel according to the invention so that the remote control is only connected to the jockey wheel when the towable vehicle is to be moved under the power of the jockey wheel. The remote control and the electrical cord can be permanently connected together or they can be releasably connected. [0016] The remote control can take any suitable form and can provide any suitable form of movement of the motorised jockey wheel which can be achieved by relative rotation of the first and second wheels. The preferred movement includes forward, backward and turning movement and the remote control can have any suitable construction or configuration that allows hand or finger manipulation to provide this movement. The remote control could for example include by suitable push buttons or a joystick. [0017] In alternative forms of the invention, the remote control can connect to the controller of the jockey wheel wirelessly. [0018] The movement of the jockey wheel is by rotation of the first and second wheels and for straight movement, the wheels can be driven by the motors at the same speed. The rotational direction can be reversed to change between forward <filename> 5 and reverse movement. Forward and backward movement will be easily provided by reversing the polarity to the motors depending on which direction is required. [0019] For turning movement, the first and second wheels can be driven at different speeds so that both wheels continue to be driven, or one of the wheels can be driven and the other wheel not driven. The later arrangement allows a simplified controller as the output power of the motors is either the same for both of the first and second motors, whereby both of the first and second wheels are driven at the same speed and the jockey wheel will move in a straight line forward or back, or output power is provided to only one of the motors, whereby only one of the first and second wheels is driven and the other is not driven. Where only one wheel is driven, the jockey wheel will turn either left or right depending on which of the wheels is driven. Thus, the controller acts to either supply power to both wheels or to one wheel only, based on the input from the remote control. The remote control could include four separate push buttons for forward, backward, left and right to facilitate this. [0020] Alternative arrangements can include more sophisticated control systems where both wheels are driven when the jockey wheel is turning. In these arrangements, the relative rotation is determined by the sharpness of the turn required and the remote control would need to provide facility for increasing or decreasing the sharpness of the turn. A joystick could be provided to facilitate this. [0021] The remote control can also include facility for actuating the caravan brakes, for example to provide for emergency braking of the caravan during use of the jockey wheel. Caravan brakes are normally electrically operated and so the jockey wheel can be in electrical communication with the braking system and be able to initiate actuation of the braking system via the remote control. The remote control can include a button for actuation of the braking system, so that depression of the button will apply the brakes to terminate movement of the caravan. [0022] The first and second motors are coupled to the first and second wheels in any suitable manner. Direct coupling is one option. Chain drive is another option. Alternatively, the coupling can be through a reduction gear arrangement whereby a first gear is attached to the output shaft of each motor and a second gear is attached to each wheel. The first gear can be of reduced diameter compared to the second <filename> 6 gear so that so that the second gear rotates at a reduced speed compared to the second gear. The first and second gears can be in direct engagement, or one or more intermediate gears can be provided between them. [0023] The gear arrangement of the invention can also include more than a single gear reduction, so that the motorised jockey wheel of the invention can operate at more than one speed. For example, the jockey wheel can include a gear arrangement in which two gear ratios are provided, being one high and one low, or three or more gear ratios could be provided, thereby providing more options for the speed at which the jockey wheel is driven. This would allow the jockey wheel to be driven more quickly when the loads on the motors permit this and slower when the motors are towards their maximum loading. Higher gears could selected where the towable vehicle is relatively light or is being moved down an incline, while lower gears could selected where the towable vehicle is relatively heavy or is being moved up an incline. The gear arrangement could also include a neutral gear position to allow the jockey wheel to free-wheel. [0024] The first and second wheels can include solid or pneumatic tyres. The tyres preferably include a tread for gripping surfaces that a towable vehicle might be moved onto. Caravans for example are likely to be moved onto grassed, sand or dirt surfaces and a tyre tread assists to grip that surface. [0025] The first and second wheels do not need to be spaced apart very far. Tyres having an outside diameter of 280mm and a tread width of 90mm can be spaced apart about 110mm from the facing inside surfaces thereof. The space between the wheels can be used to house the controller and the electrical wiring that extends from the controller to the first and second motors. The motors can also be housed within this space although in alternative arrangements, they can be housed approximately in line with the wheels and either forward or behind them. [0026] Power to drive the first and second motors can be provided by a dedicated battery which is mounted on the motorised jockey wheel, or more preferably, the jockey wheel of the invention includes facility to connect to the power source of the towable vehicle where that vehicle includes a suitable source. Caravans for example generally include an onboard power source to drive electrical components of the <filename> 7 caravan (including the electric brakes) and that source can be used to power the motorised jockey wheel of the invention. Accordingly, the jockey wheel of the invention can include suitable wiring for connecting to the power source and by this arrangement, a dedicated battery is not required. This means that the disadvantages that are associated with the need for a dedicated battery are avoided, including the most inconvenient being that the battery is out of charge when the jockey wheel is intended to be used. It is much less likely that the power source of the caravan will be out of charge, given that when the caravan is being used, the power source will be regularly replenished and when the caravan is to be used after a period of inactivity, one of the preparations for use is to check the state of the charge of the power source. [0027] The controller can have any suitable construction and in a form developed to date, the controller includes a printed circuit board that controls delivery of power to the first and second motors. [0028] The motorised jockey wheel of the invention can include a shroud or body cover that partially encloses some of the components discussed above, including the chassis, the first and second motors, the controller, the first and second wheels and the drive between the motors and the wheels if provided. The cover can be for protective and aesthetic purposes. BRIEF DESCRIPTION OF THE DRAWINGS [0029] In order that the invention may be more fully understood, some embodiments will now be described with reference to the figures in which: [0030] Figure 1 is a front view of a jockey wheel according to the invention. [0031] Figure 2 is a side view of the jockey wheel of Figure 1. [0032] Figure 3 is an end view of the jockey wheel of Figure 1. [0033] Figure 4 is a further front view of the jockey wheel of Figure 1. [0034] Figure 5 is an underneath view of the jockey wheel of Figure 1. <filename> 8 DETAILED DESCRIPTION OF THE DRAWINGS [0035] Figures 1 to 3 are front, side, and end views of a jockey wheel 10, according to the invention. With reference to those figures, the jockey wheel 10 includes a chassis (not visible in those figures), an upstanding jockey wheel post 11, first and second wheels 12 and 13 which are spaced apart as shown in Figures 1 and 3, but which rotate about the same axis, and a cover 14. [0036] The jockey wheel 10 further includes an electrical power cord 15 and a port 16 for connection of a remote control 18 (Figure 4). The electrical cord 15 includes a pair of connectors 17 for connection to an extension cord that can extend to a suitable connection with an onboard power source. [0037] Figure 4 is the same illustration as Figure 1, except that a remote control 18 has been connected by a coiled electrical cord 19 to the port 16. It can be seen in Figure 4, that the electrical cord 19 is quite long and will extend further than its illustrated cord length by stretching, allowing an operator of the jockey wheel 10 to move a distance away from the jockey wheel 10 and still control its movement via the remote control. [0038] From Figures 1 to 3 it can be seen that the cover 14 provides coverage for the majority of the components of the jockey wheel 10, except for the side faces of the wheels 12 and 13. Access to those side faces is required for inflating the tires and for removing the wheels if required. [0039] Figure 5 is an underneath view of the jockey wheel 10 and in this view, first and second motors 24 and 25 are shown, as well as the gear drive between the motors 24 and 25, and the wheels 12 and 13. That gear drive comprises a first gear 35 (which is shown only in respect of the wheel 13 in Figure 5), which is attached to the output shaft of each of the motors 24 and 25 and which meshes with an intermediate gear 26 which in turn meshes with a second gear 27 which is attached to each of the wheels 12 and 13. [0040] Figure 5 also illustrates the common axle 28 about which the wheels 12 and 13 rotate, and the chassis 29 to which the axle 28 is attached. <filename> 9 [0041] The chassis 29 includes a pair of lengthwise plates 30 which extend to an end plate 31 which is bolted to an inside surface of the cover 14. The chassis is also connected to the post 11 on the inside of the cover 14. [0042] A controller 33 is disposed between the plates 30 and is electrically connected to both the power cord 15 and the port 16. The controller 33 is further electrically connected to each of the motors 24 and 25. The controller includes a printed circuit board for controlling delivery of power from the power cord 15 through to the motors 24 and 25. [0043] With the power cord 15 connected to the power source of the vehicle being towed, the jockey wheel 10 is ready for actuation. By depressing the button 34 (Figure 3) the jockey wheel 10 is activated and actuation by the remote control 18 can be initiated. [0044] The remote control 18 includes push buttons for forward, backward and left and right movement and when the forward or backward buttons are pressed, each of the wheels 12 and 13 is driven and at the same speed in the appropriate direction. [0045] When either of the left or right buttons is pressed, power to one of the motors 24 and 25 is terminated and the wheel associated with the respective motor stops turning. The other wheel continues turning and by that arrangement, the jockey wheel 10 will turn. [0046] The remote control 18 as illustrated does not include a button for actuation of the braking system of a caravan to which the jockey wheel is connected. However, as discussed above, such a facility for actuating the caravan brakes can be provided and the remote control 18 can include a button for that purpose. [0047] Once the jockey wheel 10 has manoeuvred the towable vehicle to the desired position, the power cord 15 can be disengaged from the on-board power source and the jockey wheel 10 will then enter an inactive mode. The jockey wheel 10 can, however, remain in place in connection with the towable vehicle and act then simply as a standard jockey wheel. Alternatively, the jockey wheel 10 can be completely disconnected from the vehicle and stored elsewhere. <filename> 10 [0048] It will be appreciated that the jockey wheel 10 can be connected and disconnected from the towable vehicle, and therefore it is not necessary for the jockey wheel 10 to accompany the towable vehicle on every journey. The jockey wheel 10 could, for example, be left at the normal storage destination of the towable vehicle and only used for manoeuvring that vehicle at that destination. [0049] Moreover it is expected that the jockey wheel 10 could have commercial use, such as in relation to commercial caravan parks or boating parks, whereby the park owner might have one or more of the jockey wheels of the invention to assist a patron to manoeuvre caravans or boats into position more easily than having to manoeuvre the caravan or boat by car. In that scenario the jockey wheel 10 could be brought out as required when requested by caravan or boating park patrons. [0050] The jockey wheel 10 is expected to be commercially produced relatively inexpensively particularly when compared to the prior art known to the Applicant. Moreover, the jockey wheel 10 is considered to be robust and should also be relatively maintenance free given the simple construction embodied in it. [0051] Throughout the description and claims of this specification the word "comprise" and variations of that word, such as "comprises" and "comprising", are not intended to exclude other additives, components, integers or steps. [0052] The invention described herein is susceptible to variations, modifications and/or additions other than those specifically described and it is to be understood that the invention includes all such variations, modifications and/or additions which fall within the spirit and scope of the present disclosure. <filename>