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Title:
A DRIVE SYSTEM AND METHOD FOR DRIVING A TRAILER
Document Type and Number:
WIPO Patent Application WO/2019/183678
Kind Code:
A1
Abstract:
The invention relates to a drive system for providing drive to the wheels of a trailer to supplement the drive of the towing vehicle. It includes a drive arrangement such as an electric motor, a transmission, a clutch, and a gearbox. The drive system further includes a control unit configured for controlling the drive arrangement, gearbox and clutch in one of a plurality of modes of operation, to supplement drive of the towing vehicle in particular situations.

Inventors:
GAJIC, Alan (86 Glenvale Street, Cornubia, Queensland 4130, 4130, AU)
Application Number:
AU2019/050276
Publication Date:
October 03, 2019
Filing Date:
March 27, 2019
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
GAJIC, Alan (86 Glenvale Street, Cornubia, Queensland 4130, 4130, AU)
International Classes:
B62D59/04; B62D63/06
Domestic Patent References:
WO2017082768A12017-05-18
Foreign References:
US5141067A1992-08-25
US4461365A1984-07-24
US7275907B12007-10-02
IES58902B21993-12-01
US1926935A1933-09-12
DE3914927A11990-11-08
US20110079453A12011-04-07
GB771510A1957-04-03
US4676330A1987-06-30
DE2705318A11978-08-10
Attorney, Agent or Firm:
BAXTER PATENT ATTORNEYS PTY LTD (Suite 2, Level 3A1 Bligh S, Sydney New South Wales 2000, 2000, AU)
Download PDF:
Claims:
Claims

1. A drive system for driving a trailer including at least one wheel, comprising a) a drive arrangement configured for imparting mechanical power to a transmission; b) a transmission functionally coupled or couplable to the drive arrangement to be driven by the drive arrangement, the transmission being configured to be coupled to the at least one wheel to provide rotational movements to the wheel, to thereby allow the wheel to be driven by the drive arrangement; and

c) a centrifugal clutch arrangement configured for disengaging the drive arrangement from the at least one wheel in use, when the at least one wheel of the trailer is being driven by contact with the ground at threshold angular velocity.

2. A drive system as claimed in claim 1 , wherein the centrifugal clutch is operable in opposed directions to transmit drive to the wheels.

3. A drive system as claimed in claim 1 , wherein the drive arrangement is configured to be reversible to transmit drive to the transmission in opposed directions.

4. A drive system as claimed in claim 1 , wherein the threshold angular velocity is an angular velocity at which the drive arrangement can be safely driven.

5. A drive system as claimed in claim 1 , wherein the threshold angular velocity is close to the top of the angular velocity range at which the drive arrangement is movable.

6. A drive system as claimed in claim 1 , wherein a drive arrangement, transmission and centrifugal clutch is associated with at least one wheel on two opposed sides of the trailer.

7. A drive system as claimed in claim 6, wherein the drive arrangement, transmission and centrifugal clutch associated with at least one wheel on opposed sides of the trailer are independently operable.

8. A drive system as claimed in claim 1 , wherein the drive system further includes at least one or more gearboxes.

9. A drive system as claimed in claim 1 , wherein the at least one or more gearboxes are located towards the drive arrangement side of the transmission from the centrifugal clutch arrangement.

10. A drive system as claimed in claim 1 , wherein the at least one or more gearboxes are located towards the wheel side of the transmission from the centrifugal clutch arrangement.

1 1 . A drive system as claimed in claim 1 , further including a control unit configured for controlling operation of one or more selected from the drive arrangement and the gearboxes.

12. A drive system as claimed in claim 1 1 , wherein the control unit is configured for operation of the drive arrangement and/or gearboxes in accordance with one of a plurality of pre-set operating characteristics.

13. A drive system as claimed in claim 1 1 , wherein the control unit is configured for receiving a control signal from the towing vehicle for selecting one or more of a plurality of pre-set operating characteristics.

14. A drive system as claimed in claim 1 1 , wherein the control unit comprises at least one or more sensors.

15. A drive system as claimed in claim 1 1 , wherein the control unit is configured for preventing transmission of power from the drive arrangement on receiving a signal received from the electrical interface indicating that the trailer is being braked.

16. A drive system as claimed in claim Error! Reference source not found., wherein the control unit is configured to actuate the drive arrangement to drive the trailer on receiving a signal indicative of wheel slip of at least one of the wheels of the towing vehicle.

17. A drive system as claimed in claim 1 , wherein the drive system further comprises a braking arrangement configured for slowing angular rotation of the wheels directly or indirectly via the transmission.

18. A drive system for driving a trailer, the trailer including at least one trailer wheel located on opposed sides of the trailer, the drive system comprising

a) at least one or more transmissions engageable with at least one wheel on each opposed side of the trailer, the at least one or more transmissions being configured to transmit power for driving the at least one trailer wheel on each opposed side of the trailer in one of two opposed directions; b) at least one or more drive arrangement configured for driving each transmission to drive the at least one trailer wheel on each opposed side of the trailer in one of two opposed directions; and

c) at least one or more clutch arrangements configured for disengaging the at least one or more drive arrangements from the at least one wheel on each opposed side of the trailer.

19. A drive system as claimed in claim 18, wherein a drive arrangement is associated with each transmission to independently drive the at least one wheel on each opposed side of the trailer in one of two opposed directions.

20. A drive system as claimed in claim 18, wherein the drive system further comprises at least one or more gearboxes associated with each transmission.

21 . A drive system as claimed in claim 18, further comprising a control unit configured for controlling drive to the trailer wheel by the drive arrangement via the transmission.

22. A drive system as claimed in claim 18, wherein control unit is configured for controlling operation of one or more selected from the at least one or more drive arrangements, the at least one or more clutch arrangements, and the at least one or more gearboxes.

23. A drive system as claimed in claim 18, wherein the control unit is configured for controlling operation of one or more selected from the at least one or more drive arrangements, the at least one or more clutch arrangements, and the at least one or more gearboxes, in accordance with one of a plurality of pre-set operating characteristics.

24. A drive system as claimed in claim 18, wherein the clutch arrangement is a centrifugal clutch arrangement.

25. A drive system for driving a trailer being towed by a towing vehicle, the trailer including at least one trailer wheel, the drive system comprising

a) at least one or more transmissions engageable with at least one wheel on each opposed side of the trailer, the at least one or more transmissions being configured to transmit power for driving the at least one trailer wheel on each opposed side of the trailer independently;

b) at least one or more drive arrangement configured for driving each transmission to drive the at least one trailer wheel on each opposed side of the trailer; and c) a control unit configured for receiving a control signal from a remote controller on the towing vehicle, the control unit further being configured for controlling drive to the trailer wheel by the drive arrangement via the transmission in accordance with the received control signal.

26. A drive system as claimed in claim 25, wherein the at least one or more drive arrangements are configured for driving each transmission to drive the at least one trailer wheel on each opposed side of the trailer independently.

27. A drive system as claimed in claim 25, wherein the at least one or more transmissions are configured for driving each transmission to drive the at least one trailer wheel on each opposed side of the trailer in one of two opposed directions.

28. A drive system as claimed in claim 25, wherein the drive arrangement is configured for driving each transmission to drive the at least one trailer wheel on each opposed side of the trailer in one of two opposed directions.

29. A drive system as claimed in claim 25, wherein the drive system further includes at least one or more gearboxes.

30. A drive system as claimed in claim 29, wherein the drive system includes at least one or more gearboxes associated with each of the transmissions.

31 . A drive system as claimed in claim 29, wherein the control unit is configured for controlling operation of one or more selected from the at least one or more drive arrangements, the at least one or more clutch arrangements, and the at least one or more gearboxes.

32. A drive system as claimed in claim 29, wherein the control unit is configured for controlling operation of one or more selected from the at least one or more drive arrangements, the at least one or more clutch arrangements, and the at least one or more gearboxes, in accordance with one of a plurality of pre-set operating characteristics.

33. A drive system as claimed in claim 25, wherein the control unit is configured for receiving a selection of one of a plurality of pre-set operating characteristics from the towing vehicle.

34. A drive system as claimed in claim 25, wherein the trailer includes a pair of wheels located on opposed sides of the trailer, and the drive system comprises a drive arrangement, transmission and clutch arrangement configured for independently driving each of the pair of wheels.

35. A trailer comprising a drive system as claimed in any one of claims 1 to 34.

Description:
A DRIVE SYSTEM AND METHOD FOR DRIVING A TRAILER

Field of the Invention

[0001 ] The present invention generally relates to towing assisting technologies for a trailer, and more particularly it relates to a drive system and method for driving and/or moving a trailer.

[0002] The invention has been developed primarily to provide assistance for motor vehicles towing a trailer and/or alike to both on and off-road setting, and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.

Background of the Invention

[0003] There are many forms of trailers available in the current market place, and typically trailers are designed to be hitched and towed by powered vehicles, for example by a truck, a van and/or a car.

[0004] When towing a trailer, especially in rugged areas such as in soft sand or deep mud, a towing vehicle may be hindered by the additional drag caused by a trailer, causing the vehicle to get bogged down. This may have serious consequences where the vehicle is travelling alone and in remote areas where help may not be available.

[0005] Another problem with trailers, and especially large off road trailers, is that they may be difficult to maneuver without the use of a vehicle, for example in a camping spot where towing vehicles are not able to access or are not authorised to access.

[0006] The present invention seeks to provide a system and method for manoeuvring and/or moving a trailer that will overcome or substantially ameliorate at least one or more of the deficiencies of a prior art, or to at least provide an alternative solution to the problems.

[0007] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country. Summary of the Invention

[0008] According to a first aspect of the invention there is provided a drive system for driving a trailer. The drive system includes a drive arrangement. The drive system includes a transmission. The drive system includes a clutch arrangement. The drive system includes a control unit. The drive system includes a power source. Drive system includes a drive arrangement. The drive arrangement preferably includes a motor. The drive system includes a transmission. The transmission preferably includes a gearbox.

[0009] According to a further aspect, there is provided a trailer including a drive system as described.

[0010] According to a further aspect of the present invention there is provided a drive system for driving a trailer including at least one wheel, comprising

a) a drive arrangement configured for imparting mechanical power to a transmission;

b) a transmission functionally coupled or coupleable to the drive arrangement to be driven by the drive arrangement, the transmission being configured to be coupled to the at least one wheel to provide rotational movements to the wheel, to thereby allow the wheel to be driven by the drive arrangement; and

c) a clutch arrangement configured for disengaging the drive arrangement from the at least one wheel in use..

[001 1 ] In one embodiment, the clutch arrangement is a centrifugal clutch arrangement operable in opposed directions to transmit drive to the wheels, the centrifugal clutch arrangement being configured for disengaging the drive arrangement from the at least one wheel in use, when the at least one wheel of the trailer is being driven by contact with the ground at threshold angular velocity.

[0012] In one embodiment, the threshold angular velocity is an angular velocity at which the drive arrangement can be safely driven.

[0013] In one embodiment, the threshold angular velocity is close to the top of the angular velocity range at which the drive arrangement is movable.

[0014] In one embodiment, the trailer includes a trailer frame and the drive arrangement is configured to be at least partly mounted or mountable to the trailer frame.

Drive arrangement

[0015] In one embodiment, the drive arrangement includes a prime mover. [0016] In one embodiment, the prime mover is a motor.

[0017] In one embodiment, the prime mover is an internal combustion engine.

[0018] In one embodiment, the motor is an electric motor.

[0019] In one embodiment, the electric motor is a winch motor.

[0020] Alternatively, the drive arrangement includes a driven coupling configured for being driven from a towing vehicle.

[0021 ] In one embodiment, the drive arrangement includes a drive gear.

[0022] In one embodiment, the drive gear is one or more selected from a gear and a sprocket.

[0023] In one embodiment the motor is operable in opposed directions.

[0024] In one embodiment, the drive arrangement includes a pair of electric motors.

[0025] In one embodiment, each electric motor is associated with its own transmission.

[0026] In one embodiment, each motor is associated with a wheel.

Power source

[0027] In one embodiment, the drive system includes a power source.

[0028] In one embodiment, the power source is a battery.

[0029] Alternatively, the drive system includes an electrical coupling for receiving electrical power from an external power source.

[0030] In one embodiment, the external power source is a battery on a towing vehicle.

[0031 ] In one embodiment, the drive arrangement includes a driven coupling configured for being driven from an external drive.

[0032] In one embodiment, the external drive is a rotatable shaft on the tow vehicle.

[0033] In one embodiment, the driven coupling is a shaft coupling configured for being driven by a rotating shaft.

[0034] In one embodiment, the transmission is configured to be functionally coupled or coupleable to at least one drive axle of the trailer.

Transmission

[0035] In one embodiment, the drive system includes a pair of transmissions. [0036] In one embodiment, the drive system includes a pair of independently driven transmissions.

[0037] In one embodiment, a transmission is associated with a wheel on each side of the trailer.

[0038] In one embodiment, each transmission includes a clutch.

[0039] In one embodiment, each transmission includes at least one or more gearboxes.

[0040] In one embodiment, the at least one or more gearboxes is located towards the drive arrangement side of the clutch.

[0041 ] In one embodiment, the at least one or more gearboxes is located towards the wheel side of the clutch.

Chain/belt driven system

[0042] In one embodiment, the transmission includes at least one or more chains and at least one or more sprockets.

[0043] In one embodiment, the transmission includes a flexible linkage driven system.

[0044] In one embodiment, the transmission includes at least one or more flexible linkages.

[0045] In one embodiment, the flexible linkage is one or more selected from a chain and a belt.

[0046] In one embodiment, the transmission includes at least one or more sprockets.

[0047] In one embodiment, the transmission includes at least one idler shaft.

[0048] In one embodiment, the transmission includes at least one or more idler sprockets mounted on the idler shaft.

[0049] In one embodiment, trailer includes a pivoting suspension strut pivotable about a pivot axis, and the idler shaft is coaxial with the pivot axis of a suspension strut of the trailer.

[0050] In one embodiment, the idler shaft is mounted on at least one or more bearings.

[0051 ] In one embodiment, the transmission includes a drivetrain for each wheel.

[0052] In one embodiment, the drive system includes a pair of drive arrangements. [0053] In one embodiment, the drive system includes a drive arrangement for each wheel.

[0054] In one embodiment, the transmission includes a plurality of flexible linkages.

[0055] In one embodiment, a first flexible linkage extends the drive arrangement and the idler shaft to rotate the idler shaft.

[0056] In one embodiment, the trailer includes a wheel hub, and a second flexible linkage extends between the idler shaft and the wheel hub of the trailer.

Direct drive electrical motor

[0057] In one embodiment, the trailer includes at least one or more wheel hubs rotatable about an axis, and the drive arrangement is configured to drive a transmission mounted on the wheel hub.

[0058] In one embodiment, the drive arrangement includes a driving gear configured to be mounted at or towards the wheel hub.

[0059] In one embodiment, the transmission mounted on the wheel hub is a complementary gear configured to engage with the driving gear.

Shaft driven system

[0060] In one embodiment, the transmission includes a drive shaft.

[0061 ] In one embodiment, the transmission includes at least one or more gears configured to be driven by and/or drive the drive shaft.

[0062] In one embodiment, the transmission includes at least one or more universal couplings.

[0063] In one embodiment, the transmission includes a differential.

[0064] In one embodiment, the differential includes one or more selected from a pinion gear, a ring gear, a side gear, a spider gear and a pair of axle shafts.

[0065] In one embodiment, the gears are one or more selected from

a) worm gears,

b) bevel gears,

c) spiral bevel gears,

d) spur gears,

e) helical gears, f) planetary gears,

g) internal gears,

h) miter gears,

i) ring gears,

j) spider gears,

k) pinion gears,

L) side gears,

m) or the like.

[0066] In one embodiment, the transmission includes at least one or more splined driveshafts configured for facilitating transmission of power through a shaft that is changing in length.

[0067] In one embodiment, the clutch arrangement is mounted to the driveshaft. Gearbox

[0068] In one embodiment, the transmission includes at least one or more gearboxes.

[0069] In one embodiment, the at least one or more gearboxes are electrically actuatable.

[0070] In one embodiment the at least one or more gearboxes are electrically actuatable by a control unit.

[0071 ] In one embodiment, the at least one or more gearboxes are configured for providi a set of discrete qear ratios between an input shaft and an output shaft.

[0072] In one embodiment, the at least one or more gearboxes are continuously variable and adapted for providing an infinitely variable set of gear ratios in a predetermined range.

Control unit

[0073] In one embodiment, the drive system further includes a control unit for controlling the drive system.

[0074] In one embodiment, the control unit includes a set of instructions for controlling the system.

[0075] In one embodiment, the control unit includes digital storage media for storing software instructions. [0076] In one embodiment, the control unit further includes an input and/or output interface unit.

[0077] In one embodiment, the control unit includes a receiver functionally connected to the control unit for receiving a control signal.

[0078] In one embodiment, the drive system further includes a receiver functionally connected to the control unit for receiving a wireless control signal.

[0079] In one embodiment, the drive system further includes a transmitter configured for transmitting a signal.

[0080] In one embodiment, the control unit includes a sensor.

[0081 ] In one embodiment, the sensor is configured for sensing the angular velocity of the wheels of the trailer.

[0082] In one embodiment, the control unit further includes a switch to terminate operation of the system.

[0083] In one embodiment, the trailer includes a trailer electrical system, and the control unit includes an electrical interface with the trailer electrical system.

[0084] In one embodiment, the control unit is configured for controlling operation of the drive arrangement in accordance with a signal received from the electrical interface.

[0085] In one embodiment, the control unit is configured for preventing transmission of power from the drive arrangement on receiving a signal received from the electrical interface indicating that the trailer is being braked.

[0086] Preferably the control unit includes a wireless controller that can be operated from a towing vehicle.

[0087] In one embodiment, the control unit includes a remote controller that can be operated from a towing vehicle.

[0088] In one embodiment, the control unit is configured to be controlled from the towing vehicle.

[0089] In one embodiment, the control unit includes an electrical interface for connection with the towing vehicle.

[0090] In one embodiment, the electrical interface is a plug.

[0091 ] In one embodiment, the control unit is configured to control the drive system automatically on receiving a signal indicative of an event occurring on the towing vehicle. [0092] In one embodiment, the control unit is configured to control actuation of at least one or more electrically actuatable clutches.

[0093] In one embodiment, the control unit is configured to receive signals from sensors.

[0094] In one embodiment, the control unit is configured to determine the angular velocity of at least a part of the transmission towards the wheels from the clutch (“downstream” of the clutch).

[0095] In one embodiment, the control unit is configured to determine the angular velocity of at least a part of the transmission towards the drive arrangement from the clutch (“upstream" of the clutch).

[0096] In one embodiment, the control unit is configured for determining the difference in speed between the transmission towards the wheel side of the clutch and the transmission towards the drive arrangement side of the clutch.

[0097] In one embodiment, the control unit is configured to control actuation of at least one or more electrically actuatable clutches to disengage the wheels from the drive arrangement on determining that the transmission downstream of the clutch has a greater angular velocity than the transmission upstream of the clutch.

[0098] In one embodiment, the control unit is configured to control operation of at least one or more gearboxes.

[0099] In one embodiment, the control unit is configured to control operation of at least one more gearboxes to select a gear ratio matching the upstream transmission angular velocity and the downstream transmission angular velocity.

[0100] In one embodiment, the control unit is configured to actuate the drive arrangement to drive the trailer on detection of wheel slip in the towing vehicle.

[0101 ] In one embodiment, the drive system further includes a braking arrangement configured for slowing angular rotation of the wheels directly or indirectly via the transmission arrangement.

[0102] In one embodiment, the control unit is configured for actuating the braking arrangement when the drive arrangement is not actuated and the vehicle is not coupled to the trailer. [0103] In one embodiment, the control unit is configured for controlling the drive arrangement to drive at least one wheel of the trailer in use according to one or more predetermined schedules and/or programs.

[0104] In one embodiment, the control unit is configured for controlling the drive arrangement to drive at least one wheel of the trailer in use according to one or more predetermined schedules and/or programs selected by an operator in the towing vehicle.

[0105] In one embodiment, the predetermined schedules and/or programs are associated with terrain types.

Clutch arrangement

[0106] In one embodiment, the clutch arrangement is an overrun clutch.

[0107] In one embodiment, the clutch arrangement is an overrun bearing.

[0108] Alternatively, the clutch arrangement is a centrifugal clutch.

[0109] In one embodiment, the drive arrangement includes an electric motor.

[01 10] In one embodiment, the drive system configured so that the drive arrangement is mounted above the trailer frame.

[01 1 1 ] In accordance with a further aspect of the present invention, there is provided a drive system for driving a trailer, the trailer including at least one trailer wheel, the drive system comprising

a) a transmission functionally engaged to a wheel of the trailer, the transmission being configured to transmit power for driving auxiliary movements of the at least one trailer wheel;

b) a drive arrangement configured for driving the transmission, at least one gear drive coordinating with the first or second body and is configured to facilitate relative movements of the wheel;

c) a clutch arrangement configured for disengaging the drive arrangement from the transmission when the at least one wheel of the trailer has a greater angular velocity than the transmission is able to impart to the wheel from the drive arrangement;

d) a power source connected to the drive arrangement for powering the system; and e) a control unit functionally connected to one or more selected from the drive arrangement and the transmission, and configured for controlling drive to the trailer wheel by the drive arrangement via the transmission;

f) wherein the control unit is configured for controlling drive to the trailer wheel in accordance with a preselected mode of operation selectable from a plurality of modes of operation.

[01 12] In one embodiment, the trailer includes at least a pair of wheels located on opposed sides of the trailer, and the system is configured for driving the pair of wheels.

[01 13] In one embodiment, each of the pair of wheels are driveable individually.

[01 14] In one embodiment, each of the pair of wheels are driveable and opposed forward and reverse directions.

[01 15] In accordance with a further aspect of the present invention, the invention may be said to consist in a method of driving a trailer including at least one wheel, including the steps of

a) providing a drive system as described above;

b) configuring a transmission to functionally engage with a wheel of the trailer to provide auxiliary movement to the trailer wheel;

c) configuring a drive arrangement to drive the transmission on actuation by a control unit; and

d) controlling a clutch arrangement to disengage the drive arrangement from the transmission when the at least one wheel of the trailer has a greater angular velocity than the transmission is able to impart to the wheel from the drive arrangement.

[01 16] In accordance with a further aspect of the present invention, there is provided a drive system for driving a trailer, the trailer including at least one trailer wheel and an electrical system, the drive system comprising

a) a transmission functionally engaged to a wheel of the trailer, the transmission being configured to transmit power for driving auxiliary movements of the at least one trailer wheel;

b) a transmission functionally coupled or coupleable to the drive arrangement to be driven by the drive arrangement, the transmission being configured to be coupled to the at least one wheel to provide rotational movements to the wheel; and c) a control unit functionally connected to one or more selected from the drive arrangement and the transmission, and configured for controlling drive to the trailer wheel by the drive arrangement via the transmission, the control unit further comprising an electrical interface with the trailer electrical system;

d) wherein the control unit is configured for controlling operation of the drive arrangement in accordance with a signal received from the electrical interface.

[01 17] In one embodiment, the control unit is configured for stopping transmission of power from the drive arrangement on receiving a signal received from the electrical interface indicating that the trailer is being braked.

[01 18] Preferably the control unit comprising a wireless controller that can be operated from a towing vehicle.

[01 19] In the, the control unit comprising a remote controller that can be operated from a towing vehicle.

[0120] Preferably the drive system includes a clutch arrangement configured for disengaging the drive arrangement from the transmission when the at least one wheel of the trailer has a greater angular velocity than the transmission is able to impart to the wheel from the drive arrangement.

[0121 ] In one embodiment, the drive system includes a power source connected to the drive arrangement for powering the drive system.

[0122] In one embodiment, the power source is a battery.

[0123] In accordance with a further aspect, the invention may be said to consist in a method of maneuvering a trailer, the method including the steps of:

a) providing a trailer and a system as described above;

b) actuating a control unit to thereby transmit drive power from the drive arrangement to the at least one trailer wheel via the transmission.

[0124] In one embodiment, the method further includes the step of powering one or more selected from the drive arrangement and the transmission from a power source.

[0125] In one embodiment, the system includes a clutch located between the drive arrangement and the wheel on the transmission, and the method further includes the step of engaging the clutch to facilitate the transfer of drive power to the wheel via the transmission . [0126] In one embodiment, the method further includes the step of disengaging the drive arrangement from the clutch on detection of actuation of the trailer’s brake lights.

[0127] In another aspect, the invention may be said to consist in a trailer configured for being towed behind a towing vehicle, the trailer comprising a drive system as described above.

[0128] In another aspect, the invention may be said to consist in a trailer, the trailer comprising:

a) a pair of wheels for supporting a load;

b) a drive arrangement configured for imparting mechanical power to a transmission;

c) a transmission functionally coupled or coupleable to the drive arrangement to be driven by the drive arrangement, the transmission being configured to be coupled to at least one wheel to provide rotational movements to the wheel; and

d) a clutch arrangement configured for disengaging the drive arrangement from the transmission when the at least one wheel of the trailer reaches a threshold angular velocity. T

[0129] In another aspect, the invention may be said to consist in a trailer, the trailer comprising:

a) a pair of wheels configured for supporting a load;

b) a drive arrangement functionally engaged to a wheel of the trailer, the transmission being configured to transmit power for driving auxiliary movements of the at least one trailer wheel;

c) a transmission functionally coupled or coupleable to the drive arrangement to be driven by the drive arrangement, the transmission being configured to be coupled to the at least one wheel to transmit rotational power to the wheel; and

d) a control unit functionally connected to one or more selected from the drive arrangement and the transmission, and configured for controlling drive to the trailer wheel by the drive arrangement via the transmission, the control unit further comprising an electrical interface with the trailer electrical system;

e) wherein the control unit is configured for controlling operation of the drive arrangement in accordance with a signal received from the electrical interface. [0130] In another aspect, the invention may be said to consist in a trailer, the trailer comprising:

a) a pair of wheels configured for supporting a load;

b) a drive arrangement functionally engaged or engageable to a wheel of the trailer, the transmission being configured to transmit power for driving auxiliary movements of the at least one trailer wheel;

c) a transmission functionally coupled or coupleable to the drive arrangement to be driven by the drive arrangement, the transmission being configured to be coupled to the at least one wheel to transmit rotational movements to the wheel; and d) a control unit functionally connected to one or more selected from the drive arrangement and the transmission, and configured for controlling drive to the trailer wheel by the drive arrangement via the transmission, the control unit being configured for connection to at least one or more sensors for sensing the angular velocity of the wheels;

e) wherein the control unit is configured for disengaging the drive arrangement from the wheel in accordance with a signal received from the sensor.

[0131 ] In one embodiment, the control unit includes a sensor for sensing the angular velocity of the wheels.

[0132] In another aspect, the present invention may be said to consist in a drive system for driving a trailer including at least one wheel, comprising

a) a drive arrangement configured for imparting mechanical power to a transmission;

b) a transmission functionally coupled or coupleable to the drive arrangement to be driven by the drive arrangement, to thereby drive the at least one wheel; and c) a control unit configured for controlling actuation of the drive arrangement to automatically drive the trailer wheels in accordance with a signal received from the towing vehicle.

[0133] In one embodiment, the signal received from the towing vehicle is a wireless signal.

[0134] In one embodiment, the control unit is configured to be controlled from the towing vehicle. [0135] In one embodiment, the control unit includes an electrical interface for connection with the towing vehicle.

[0136] In one embodiment, the electrical interface is a plug.

[0137] In one embodiment, the control unit is configured to control the drive system automatically on receiving a signal indicative of an event occurring on the towing vehicle.

[0138] In one embodiment, the control unit is configured to actuate the drive arrangement to drive the trailer on detection of wheel slip in the towing vehicle.

[0139] In one embodiment, the drive system further includes a braking arrangement configured for slowing angular rotation of the wheels directly or indirectly via the transmission arrangement.

[0140] In one embodiment, the control unit is configured for actuating the braking arrangement when the drive arrangement is not actuated and the vehicle is not coupled to the trailer.

[0141 ] In one embodiment, the drive system includes clutch arrangement configured for disengaging the drive arrangement from the transmission when the at least one wheel of the trailer has a greater angular velocity than the transmission is able to impart from the drive arrangement.

[0142] According to a further aspect of the present invention there is provided a drive system for driving a trailer including at least one wheel, comprising

a) a drive arrangement configured for imparting mechanical power to a transmission;

b) a transmission functionally coupled or couplable to the drive arrangement to be driven by the drive arrangement, the transmission being configured to be coupled to the at least one wheel to provide rotational movements to the wheel, to thereby allow the wheel to be driven by the drive arrangement; and

c) a centrifugal clutch arrangement operable in opposed directions to transmit drive to the wheels, the centrifugal clutch arrangement being configured for disengaging the drive arrangement from the at least one wheel in use, when the at least one wheel of the trailer is being driven by contact with the ground at threshold angular velocity.

[0143] In one embodiment, the threshold angular velocity is an angular velocity at which the drive arrangement can be safely driven. [0144] In one embodiment, the threshold angular velocity is close to the top of the angular velocity range at which the drive arrangement is movable.

[0145] In another aspect, the present invention may be said to consist in a drive system for a trailer, the drive system comprising:

a) at least one or more drive arrangements configured for imparting mechanical power to a transmission;

b) at least one or more transmissions configured for coupling the drive arrangement to at least one or more wheels of the trailer;

c) at least one or more electrically controllable clutches, the at least one or more electrically controllable clutches being configured to be electrically actuatable to decouple the at least one or more wheels wheel from the at least one or more drive arrangements; and

d) a control system configured for actuating the at least one or more electrically controllable clutches.

[0146] In one embodiment, the control system is configured for receiving signals from sensors.

[0147] In one embodiment, the drive system includes sensors for sensing one or more selected from

a) angular velocity along any point of the transmission;

b) an electrical characteristic of the motor, including voltage, power and/or current;

c) angular velocity of the electrical motor;

d) any other characteristic of the trailer, drive system or towing vehicle.

[0148] In one embodiment, the control unit includes a set of instructions for controlling the system.

[0149] In one embodiment, the control unit includes digital storage media for storing software instructions.

[0150] In one embodiment, the control unit further includes an input and/or output interface unit.

[0151 ] In one embodiment, the control unit includes a receiver functionally connected to the control unit for receiving a control signal. [0152] In one embodiment, the drive system further includes a receiver functionally connected to the control unit for receiving a wireless control signal.

[0153] In one embodiment, the drive system further includes a transmitter configured for transmitting a signal.

[0154] In one embodiment, the control unit includes a sensor.

[0155] In one embodiment, the sensor is configured for sensing the angular velocity of the wheels of the trailer.

[0156] In one embodiment, the control unit further includes a switch to terminate operation of the system.

[0157] In one embodiment, the trailer includes a trailer electrical system, and the control unit includes an electrical interface with the trailer electrical system.

[0158] In one embodiment, the control unit is configured for controlling operation of the drive arrangement in accordance with a signal received from the electrical interface.

[0159] In one embodiment, the control unit is configured for preventing transmission of power from the drive arrangement on receiving a signal received from the electrical interface indicating that the trailer is being braked.

[0160] Preferably the control unit includes a wireless controller that can be operated from a towing vehicle.

[0161 ] In one embodiment, the control unit includes a remote controller that can be operated from a towing vehicle.

[0162] In one embodiment, the control unit is configured to be controlled from the towing vehicle.

[0163] In one embodiment, the control unit includes an electrical interface for connection with the towing vehicle.

[0164] In one embodiment, the electrical interface is a plug.

[0165] In one embodiment, the control unit is configured to control the drive system automatically on receiving a signal indicative of an event occurring on the towing vehicle.

[0166] In one embodiment, the control unit is configured to control actuation of at least one or more electrically actuatable clutches.

[0167] In one embodiment, the control unit is configured to receive signals from sensors. [0168] In one embodiment, the control unit is configured to determine the angular velocity of at least a part of the transmission towards the wheels from the clutch (“downstream” of the clutch).

[0169] In one embodiment, the control unit is configured to determine the angular velocity of at least a part of the transmission towards the drive arrangement from the clutch (“upstream" of the clutch).

[0170] In one embodiment, the control unit is configured for determining the difference in speed between the transmission towards the wheel side of the clutch and the transmission towards the drive arrangement side of the clutch.

[0171 ] In one embodiment, the control unit is configured to control actuation of at least one or more electrically actuatable clutches to disengage the wheels from the drive arrangement on determining that the transmission downstream of the clutch has a greater angular velocity than the transmission upstream of the clutch.

[0172] In one embodiment, the control unit is configured to control operation of at least one or more gearboxes.

[0173] In one embodiment, the drive system includes a gearbox.

[0174] In one embodiment, the drive system includes a transmission associated with each side of the trailer.

[0175] In one embodiment, the drive system includes a gearbox associated with each transmission.

[0176] In one embodiment, the control unit is configured to control operation of at least one more gearboxes to select a gear ratio matching the relative proportions upstream transmission angular velocity and the downstream transmission angular velocity.

[0177] In one embodiment, the control unit is configured to actuate the drive arrangement to drive the trailer on detection of wheel slip in the towing vehicle.

[0178] In one embodiment, the drive system further includes a braking arrangement configured for slowing angular rotation of the wheels directly or indirectly via the transmission arrangement.

[0179] In one embodiment, the control unit is configured for actuating the braking arrangement when the drive arrangement is not actuated and the vehicle is not coupled to the trailer. [0180] In one embodiment, the control unit is configured for controlling the drive arrangement to drive at least one wheel of the trailer in use according to one or more predetermined schedules and/or programs.

[0181 ] In one embodiment, the control unit is configured for controlling the drive arrangement to drive at least one wheel of the trailer in use according to one or more predetermined schedules and/or programs selected by an operator in the towing vehicle.

[0182] In one embodiment, the predetermined schedules and/or programs are associated with terrain types.

[0183] In another aspect, the present invention may be said to consist in a drive system for a trailer, the drive system comprising:

a) a drive arrangement configured for imparting mechanical power to a transmission;

b) at least one or more transmissions configured for coupling the drive arrangement to at least one or more wheels of the trailer;

c) at least one or more electrically controllable gearboxes located along the at least one or more transmissions; and

d) a control system configured for actuating the at least one or more electrically controllable gearboxes.

[0184] In one embodiment, the drive system includes at least one or more electrically controllable clutch associated with the transmission, the electrically controllable clutch being configured to be electrically actuatable to decouple the wheels from the drive arrangement.

[0185] In one embodiment, the control system is configured for controlling actuation of the electrically controllable clutch.

[0186] In another aspect, the present invention may be said to consist in a drive system for driving a trailer including at least one wheel, comprising

a) a drive arrangement configured for imparting mechanical power to a transmission;

b) a transmission functionally coupled or couplable to the drive arrangement to be driven by the drive arrangement, the transmission being configured to be coupled to the at least one wheel to provide rotational movements to the wheel, to thereby allow the wheel to be driven by the drive arrangement; and

c) a centrifugal clutch arrangement configured for disengaging the drive arrangement from the at least one wheel in use, when the at least one wheel of the trailer is being driven by contact with the ground at threshold angular velocity.

[0187] In one embodiment, the centrifugal clutch is operable in opposed directions to transmit drive to the wheels.

[0188] In one embodiment, the drive arrangement is configured to be reversible to transmit drive to the transmission in opposed directions.

[0189] In one embodiment, the threshold angular velocity is an angular velocity at which the drive arrangement can be safely driven.

[0190] In one embodiment, the threshold angular velocity is close to the top of the angular velocity range at which the drive arrangement is movable.

[0191 ] In one embodiment, a drive arrangement, transmission and centrifugal clutch is associated with at least one wheel on two opposed sides of the trailer.

[0192] In one embodiment, the drive arrangement, transmission and centrifugal clutch associated with at least one wheel on opposed sides of the trailer are independently operable.

[0193] In one embodiment, the drive system further includes at least one or more gearboxes.

[0194] In one embodiment, the at least one or more gearboxes are located towards the drive arrangement side of the transmission from the centrifugal clutch arrangement.

[0195] In one embodiment, the at least one or more gearboxes are located towards the wheel side of the transmission from the centrifugal clutch arrangement.

[0196] In one embodiment, the drive system further includes a control unit configured for controlling operation of one or more selected from the drive arrangement and the gearboxes.

[0197] In one embodiment, the control unit is configured for operation of the drive arrangement and/or gearboxes in accordance with one of a plurality of pre-set operating characteristics. [0198] In one embodiment, the control unit is configured for receiving a control signal from the towing vehicle for selecting one or more of a plurality of pre-set operating characteristics.

[0199] In one embodiment, the control unit comprises at least one or more sensors.

[0200] In one embodiment, the control unit is configured for preventing transmission of power from the drive arrangement on receiving a signal received from the electrical interface indicating that the trailer is being braked.

[0201 ] In one embodiment, the control unit is configured to actuate the drive arrangement to drive the trailer on receiving a signal indicative of wheel slip of at least one of the wheels of the towing vehicle.

[0202] In one embodiment, the drive system further comprises a braking arrangement configured for slowing angular rotation of the wheels directly or indirectly via the transmission.

[0203] In another aspect, the present invention may be said to consist in a drive system for driving a trailer, the trailer including at least one trailer wheel located on opposed sides of the trailer, the drive system comprising

a) at least one or more transmissions engageable with at least one wheel on each opposed side of the trailer, the at least one or more transmissions being configured to transmit power for driving the at least one trailer wheel on each opposed side of the trailer in one of two opposed directions;

b) at least one or more drive arrangement configured for driving each transmission to drive the at least one trailer wheel on each opposed side of the trailer in one of two opposed directions; and

c) at least one or more clutch arrangements configured for disengaging the at least one or more drive arrangements from the at least one wheel on each opposed side of the trailer.

[0204] In one embodiment, a drive arrangement is associated with each transmission to independently drive the at least one wheel on each opposed side of the trailer in one of two opposed directions.

[0205] In one embodiment, the drive system further comprises at least one or more gearboxes associated with each transmission. [0206] In one embodiment, the drive system further includes a control unit configured for controlling drive to the trailer wheel by the drive arrangement via the transmission.

[0207] In one embodiment, the control unit is configured for controlling operation of one or more selected from the at least one or more drive arrangements, the at least one or more clutch arrangements, and the at least one or more gearboxes.

[0208] In one embodiment, the control unit is configured for controlling operation of one or more selected from the at least one or more drive arrangements, the at least one or more clutch arrangements, and the at least one or more gearboxes, in accordance with one of a plurality of pre-set operating characteristics.

[0209] In one embodiment, the clutch arrangement is a centrifugal clutch arrangement.

[0210] In another aspect, the present invention may be said to consist in a drive system for driving a trailer being towed by a towing vehicle, the trailer including at least one trailer wheel, the drive system comprising

a) at least one or more transmissions engageable with at least one wheel on each opposed side of the trailer, the at least one or more transmissions being configured to transmit power for driving the at least one trailer wheel on each opposed side of the trailer independently;

b) at least one or more drive arrangement configured for driving each transmission to drive the at least one trailer wheel on each opposed side of the trailer; and

c) a control unit configured for receiving a control signal from a remote controller on the towing vehicle, the control unit further being configured for controlling drive to the trailer wheel by the drive arrangement via the transmission in accordance with the received control signal.

[021 1 ] In one embodiment, the at least one or more drive arrangements are configured for driving each transmission to drive the at least one trailer wheel on each opposed side of the trailer independently.

[0212] In one embodiment, the at least one or more transmissions are configured for driving each transmission to drive the at least one trailer wheel on each opposed side of the trailer in one of two opposed directions. [0213] In one embodiment, the drive arrangement is configured for driving each transmission to drive the at least one trailer wheel on each opposed side of the trailer in one of two opposed directions.

[0214] In one embodiment, the drive system further includes at least one or more gearboxes.

[0215] In one embodiment, the drive system includes at least one or more gearboxes associated with each of the transmissions.

[0216] In one embodiment, the control unit is configured for controlling operation of one or more selected from the at least one or more drive arrangements, the at least one or more clutch arrangements, and the at least one or more gearboxes.

[0217] In one embodiment, the control unit is configured for controlling operation of one or more selected from the at least one or more drive arrangements, the at least one or more clutch arrangements, and the at least one or more gearboxes, in accordance with one of a plurality of pre-set operating characteristics.

[0218] In one embodiment, the control unit is configured for receiving a selection of one of a plurality of pre-set operating characteristics from the towing vehicle.

[0219] In one embodiment, the trailer includes a pair of wheels located on opposed sides of the trailer, and the drive system comprises a drive arrangement, transmission and clutch arrangement configured for independently driving each of the pair of wheels.

[0220] In another aspect, the present invention may be said to consist in a trailer including a drive system as described above.

Brief Description of the Drawings

[0221 ] Notwithstanding any other forms which may fall within the scope of the present invention, a number of preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying figures in which:

[0222] Figure 1 shows a top view of a first embodiment of a drive system functionally engaged to a pair of trailer axles;

[0223] Figure 2 shows a side view of the drive system of figure 1 ;

[0224] Figure 3 shows a close-up view of figure 1 , showing the drive arrangement engaging with the transmission; [0225] Figure 4 shows a front perspective view of a second embodiment of a drive system 1 shown in position mounted on a suspension strut of a trailer;

[0226] Figure 5 shows a top left front perspective view of a drive system of figure 4 shown in position on a trailer frame;

[0227] Figure 6 shows a close-up view of figure 5, showing the drive arrangement engaging with a complementary cylindrical gear of the transmission;

[0228] Figure 7 shows a rear perspective view of the drive system of figure 4 shown in position relative to a suspension strut of a trailer;

[0229] Figure 8 shows a cutaway top left rear perspective view of a third embodiment of a drive system on a trailer including tandem axles;

[0230] Figure 9 shows a top left rear perspective view of a fourth embodiment of a drive system mounted relative to a suspension strut of a trailer;

[0231 ] Figure 10 shows a top left rear perspective view of the drive system of figure 9;

[0232] Figure 11 shows a top view of a fifth embodiment of a drive system mounted relative to a trailer frame and trailer suspension strut;

[0233] Figure 12 shows a left side view of a sixth embodiment of a drive system mounted relative to a trailer frame and trailer suspension strut;

[0234] Figure 13 shows a left side view of the drive system of figure 12 mounted relative to a trailer, the trailer mounted to a towing vehicle;

[0235] Figure 14 shows a perspective view of the inside of a differential;

[0236] Figure 15 shows a front view of a seventh embodiment of a drive system mounted relative to a trailer suspension strut;

[0237] Figure 16 shows a left side view of an eight embodiment of a drive system mounted relative to a trailer suspension strut, directly driving the wheel of the trailer; and

[0238] Figure 17 shows a schematic view of a ninth embodiment of a drive system.

Detailed Description of Embodiments

[0239] It should be noted in the following description that like or the same reference numerals in different embodiments denote the same or similar features. [0240] In a first aspect of the invention, a drive system is provided and described in the specification using reference numeral 100, and a trailer is described using reference numeral 1000.

[0241 ] The trailer 1000 is preferably an off-road type trailer or caravan, or similar towed vehicle. The trailer 1000 typically comprises a frame 1 100 (shown in figure 4), and at least one wheel axle 1300, and preferably at least two wheels 1400 (shown in figure 2). It is envisaged that trailer 1000 can include a wheel hub assembly 1200 associated with each wheel, each wheel hub assembly 1200 being rotatable on bearings (not shown) about the wheel axle 1300, and will have a pair of wheels 1400 associated with and located on opposed sides of each axle 1300. The trailer 1000 could have more than one axle 1300 (for example as a tandem axle trailer), each preferably associated with at least one pair of wheels. Each wheel can be associated with its own mounted wheel axle 1300, or a pair of wheels (or more) can be mounted on each wheel axle 1300. In this respect, more than one wheel axle 1300 can be provided.

[0242] The frame 1 100 of the trailer 1000 can include a base frame 1 1 10 and a suspension strut 1 120 that is pivotably movable relative to the base frame 1 1 10. The suspension strut 1 120 is pivotably movable relative to the base frame 1 1 10 about a pivoting joint (not shown). The suspension strut 1 120 provides suspension via a set of coil springs 1 122 (as shown in figures 4, 5, 7, 8, and 9) or leaf springs 1 126 (as shown in figures 12 and13), and dampers 1 124. In another embodiment (not shown), one or more axles may be mounted on a pair of leaf springs, without the axle being mounted on a suspension strut.

[0243] The drive system 100 is generally configured to provide temporary drive to the wheels of the trailer in order to supplement and assist the drive of a towing vehicle 2000. This may be to assist in the traverse of a rugged, muddy, sandy or boggy terrain, thereby preventing the vehicle and trailer from getting stuck, or to assist in drive on an uphill. The drive system 100 is preferably configured to be mounted on the trailer frame 1 100.

[0244] In general, the drive system 100 includes a prime mover or drive arrangement 1 10 configured for providing mechanical drive such as an electric motor or internal combustion engine(although this is not preferred), and a transmission 120 configured for transmitting in the mechanical drive into rotational movement of the trailer wheels. The drive system 100 further includes a clutch arrangement or clutch 140. In one embodiment, the clutch 140 is configured for disengaging the drive arrangement from the transmission when the wheels are driving the transmission at a greater angular velocity than the drive arrangement is able to drive the transmission at, such as an overrun clutch, freewheel clutch, sprag clutch or overrun bearing 144. It will be appreciated that an overrun clutch or overrun bearing will only allow the transmission of torque in a single direction from the drive arrangement 1 10 to the wheels 1400.

[0245] In another embodiment, the clutch 140 is configured for disengaging the drive arrangement from the transmission when the clutch is being driven at or above a threshold angular velocity, such as a centrifugal clutch 142. It will be appreciated that a centrifugal clutch will for the allow the transmission of torque in two directions (i.e. to facilitate the movement of the trailer both in a forward direction and a backward direction), depending on the direction of movement of the prime mover. In the case of the prime mover being an electric motor, movement in opposed directions is envisaged, thereby driving movement of the wheels both in a forward and a reverse direction, depending on the direction of movement of the electric motor. The speed of the driving movement would be limited by the angular velocity at which the centrifugal clutch disengages the drive arrangement 1 10 from the wheels.

[0246] In another embodiment shown in figure 17, the clutch may be an electronically controlled clutch that is operable by a control unit, for examples by actuation of a solenoid (not shown) to engage a first part of a transmission with another part of the transmission or wheel. Such clutches are known and their operation will not be discussed in detail. It is envisaged that the transmission will be protected by careful monitoring of the transmission by sensors as described, and control of the clutching function by the control unit as described below.

[0247] In any of these clutch types, a first portion of the clutch is preferably rigidly connected to the transmission associated with and coupled to the prime mover. A second portion of the clutch is preferably rigidly connected to the transmission associated with and coupled to the wheels.

[0248] The drive system 100 further includes a power source 160, preferably in the form of a battery 162, or a fuel tank (not shown) although this is not preferred. The battery 162 is preferably securely mounted on the frame 1 100 of the trailer 1000 in a suitable mounting. In an alternative embodiment, it is also envisaged that the drive system 100 could be powered from an external power source, such as a battery on the towing vehicle, via an electrical coupling (not shown) or plug, and preferably via the electrical coupling of the trailer to the towing vehicle.

First embodiment [0249] A first embodiment of a drive system 100 is shown in figures 1 - 3. The drive system 100 includes a drive arrangement 1 10 and a transmission 120.

[0250] The drive arrangement 1 10 includes an electric motor 1 12, preferably in the form of a winch motor, a shaft 1 16 and a sprocket 1 14. The electric motor 1 12 drives the shaft 1 16. The sprocket 1 14 is securely mounted on the shaft 1 16 of the electric motor 1 12, and is configured for engagement with a complementary sprocket 122 of the transmission 120.

[0251 ] Each of the complementary sprockets 122 are mounted on a clutch arrangement 140 as will be described below. One portion of the clutch arrangement is coupled to the complementary sprocket 122 to rotate with the drive arrangement 1 10, while another portion of the clutch arrangement is coupled to the transmission 120, to rotate with the transmission.

[0252] The clutch arrangement 140 is shown in figures 1 and 2 as a pair of centrifugal clutches 142. The centrifugal clutches 142 are configured for disengaging the wheels from the drive arrangement when the angular velocity of the centrifugal clutch reaches a threshold value. The threshold value is preferably predetermined as being an angular velocity which the drive arrangement is able to rotate at, so that the drive arrangement is not damaged by being turned via the wheels at an angular velocity higher than it is capable of. The effect of the configuration of the clutch 140 is described in more detail below, with reference to its use.

[0253] The two portions of the clutch arrangement are coupled by a reconfigurable clutching arrangement (not shown) as is known for use in a centrifugal type clutch. Such reconfigurable clutching arrangements are known and full discussion of the working of such clutches is not considered within the scope of this specification. However, it will be appreciated that such clutches can operate to transmit drive from the electric motor in both directions, and allow the electric motors to be operated in a reverse direction to drive the wheels in a corresponding reverse direction.

[0254] In the embodiment shown in figures 1 - 3, a flexible linkage driven transmission 120 is shown. The transmission 120 includes a rotating transmission shaft 124 on which the clutch 140 and associated complementary sprocket 122 is mounted. A first portion of the clutch 140 is preferably keyed, or otherwise securely connected, to the transmission shaft 124 to rotate with the transmission shaft. The transmission shaft 124 is preferably mounted on a base frame 1 1 10 of the trailer on either bushings or bearings, and preferably towards the side of the trailer near a tow hitch 1500 of the trailer 1000 (shown in figures 12 and 13). The transmission shaft 124 is mounted on bearings 126 to rotate when being driven by the electric motor 1 12 via the sprocket 1 14 and complementary sprocket 122, unless the clutch 140 has operated to disengage the transmission shaft 124 from the drive arrangement 1 10.

[0255] The transmission shaft 124 is provided with first gear sprockets 128 that are located at or towards opposed ends of the transmission shaft 124. The first gear cogs 128 are preferably keyed into the transmission shaft 124 to rotate together with the transmission shaft 124.

[0256] The transmission 120 further includes flexible linkages in the form of a pair of transmission chains 130. A transmission chain 130 engages with each of the first gear sprockets 128 to be driven by the first gear sprockets. Each of the transmission chains 130 extend to a wheel hub assembly 1200 of the trailer 1000 where they engage with a second gear sprocket 132. Each of the second gear sprockets 132 are associated with and securely connected to a trailer wheel axle 1300, so that when the second gear sprockets 132 are driven by the transmission chains 130, they will cause the wheels 1400 to turn.

[0257] It is envisaged that in alternative embodiments, the second gear sprockets 132 need not necessarily be directly connected to the trailer wheel axle 1300, but could instead be securely connected to a wheel hub assembly 1200, with the second gear sprocket and wheel both being rotatably mounted to a stationary wheel axle via a wheel bearing (not shown), as will be described in alternative embodiments below.

[0258] In an alternative embodiment (not shown), it is envisaged that alternative flexible linkages, such as drive belts could be used instead of chains.

[0259] It is envisaged that the transmission 120 can include a chain tensioner arrangement 134 (shown in figure 2) for keeping the transmission chain 130 under tension. Chain tensioner arrangements are well known, and a detailed description of the workings of the chain tensioner arrangement 134 is beyond the scope of this specification.

[0260] In the embodiment shown in figures 1 - 3, a pair of centrifugal clutches 142 are shown, each centrifugal clutch 142 associated with a complementary sprocket 122. A centrifugal clutch 142 operates to disengage the transmission 120 from the drive arrangement 1 10 when the angular velocity of the transmission 120 or drive arrangement 1 10 exceeds a threshold level. The effect of this disengagement will be described in more detail below, with reference to the use of the drive system 100. Second embodiment

[0261 ] In the embodiment shown in figures 4 - 7, the electric motor 1 12 drives the rotation of a cylindrical gear drive 1 15. The cylindrical gear drive 1 15 in turn meshes with a complementary cylindrical gear 123 to drive it. The complementary cylindrical gear 123 is mounted on a clutch arrangement 140 in the form of an overrun bearing 144 that includes a first portion (not shown) and a second portion (not shown) that are movable relative to each other. The first portion of the overrun bearing is securely mounted to the complementary cylindrical gear 123, while the second portion of the overrun bearing 144 is mounted securely to shaft 124. Overrun bearings, sprag clutches or overrun clutches are well known, and a description of the workings of an overrun bearing is considered beyond the scope of the specification.

[0262] At each opposed end of shaft 124, a first sprocket 128 is provided, which is securely mounted on shaft 124 to rotate therewith. A flexible linkage in the form of a transmission chain 130 engages with each first sprocket 128, and extends to a second sprocket 132, so that when the first sprocket 128 is rotated, this will cause second sprocket 132 to rotate. Again, in an alternative embodiment (not shown), the flexible linkage could be a drive belt.

[0263] The second sprocket 132 is preferably connected to a wheel hub assembly 1200 of the trailer, to cause the vehicle to rotate when the second sprocket 132 rotates.

[0264] In the embodiment shown in figures 4-7, the clutch arrangement 140 is an overrun bearing 144 on which complementary cylindrical gear 123 is mounted for rotation. The overrun bearing 144 is mounted and is configured to operate to transmit power from the drive arrangement 1 10 to the transmission 120, to thereby drive the transmission at the speed that the drive arrangement is being powered at. However, when the transmission 120, being connected to the trailer wheels, is rotating at a higher speed than the drive arrangement 1 10, then the overrun bearing will operate to disengage the drive arrangement from the transmission, thereby preventing the transmission from driving the drive arrangement. The effect of this disengagement will be described in more detail below, with reference to the use of the drive system 100.

[0265] It will be appreciated by those skilled in the art that the clutch 140 could be mounted at any point along the transmission drive train. It is envisaged that in a preferred alternative embodiment, the overrun bearing could be mounted directly to the wheel hub, so that rotating movement of the trailer wheels 1400 during ordinary driving where the drive system 100 is not required does not cause the transmission to be driven. This is desirable in order to prevent, for examples, excessive friction being induced in the transmission at higher speeds such as on a motorway.

Third embodiment

[0266] A third embodiment of a drive system 100 is shown in figure 8, for use on a trailer having two pairs of pivoting independent suspension struts 1 120 on which separate wheel axles 1300 are mounted. In this embodiment, a drive arrangement 1 10 driven by an electric motor 1 12 causes a first drive sprocket 1 14a to rotate. The first drive sprocket 1 14a is connected by a flexible linkage, in the form of a transmission chain 130a, to a second drive sprocket 1 14b. Each of the first drive sprocket 1 14a and the second drive sprocket 1 14b are mounted on associated driveshafts 124a and 124b, and securely connected to the driveshafts to rotate with them. The driveshafts 124a and 124b are each mounted by bushings or bearings (not shown) to the frame 1 100. At opposed ends of the driveshafts 124a and 124b, a third sprocket 1 14c and fourth sprocket 1 14d are located. Each of the third sprocket 1 14c and the fourth sprocket 1 14d are connected by a transmission chain 130b and 130c to a fifth sprocket 1 14e and sixth sprocket 1 14f, respectively. Each of fifth sprocket 1 14e and sixth sprocket 1 14f are mounted to a first portion of an overrun bearing 144. The overrun bearing 144 includes a second portion that is movable relative to the first portion, and the second portion of the overrun bearing is mounted to rotate with the trailer wheel. The overrun bearing is configured so that drive from the drive arrangement is transmitted through the transmission to the wheel. However, where the wheel is being turned by contact with the ground, and the angular velocity of the wheel is faster than the angular velocity being imparted by the transmission, then the overrun bearing 144 will disengage.

[0267] Preferably, the driveshafts 124a and 124b are mounted coaxially with a pivot axis of the suspension struts 1 120 (shown as reference numeral A in figure 8). In this way, pivoting movement of the suspension struts 1 120 will not result in the increase or decrease of distance between the rotational axes of the third sprocket 1 14c and the fifth sprocket 1 14e, or the distance between the rotational axes of the fourth sprocket 1 14d and the sixth sprocket 1 14f, so that the transmission chains 130b and 130c are not stretched, or do not lose tension.

Fourth embodiment

[0268] In a fourth embodiment shown in figures 9 - 10, an electric motor 1 12 causes a first sprocket 1 14a to rotate. The first sprocket 1 14a is connected to a second sprocket 1 14b via a first transmission chain 130a. The second sprocket 1 14b is mounted on a first drive shaft 124a. Driveshaft 124a is mounted to the trailer frame 1 100 by bushings or bearings (not shown). Third sprocket 1 14c and fourth sprocket 1 14d are mounted at opposed ends of driveshaft 124a. Third sprocket 1 14c and fourth sprocket 1 14d are coupled to fifth sprocket 1 14e and sixth sprocket 1 14f by second transmission chain 130b and third transmission chain 130c, respectively, to thereby cause fifth sprocket 1 14e and sixth sprocket 1 14f to rotate when driveshaft 124a is rotating.

[0269] Fifth sprocket 1 14e and sixth sprocket 1 14f are each in turn securely mounted on second driveshaft 124b and third driveshaft 124c. Seventh sprocket 1 14g and eighth sprocket 1 14h are securely mounted to, and located on opposed ends of second driveshaft 124b and third driveshaft 124c, and configured to rotate when fifth sprocket 1 14e and sixth sprocket 1 14f rotate.

[0270] Seventh sprocket 1 14g and eighth sprocket 1 14h are each operably coupled to ninth sprocket 1 14i and tenth sprocket 1 14j by fourth transmission chain 130d and fifth transmission chain 130e, respectively, so that they will rotate together.

[0271 ] Ninth sprocket 1 14i and tenth sprocket 1 14j are each connected to the wheel hub assembly 1200 to rotate with a wheel (not shown in figures 9 - 10). In a preferred embodiment, the second driveshaft 124b and third driveshaft 124c are mounted to be coaxial with the pivoting axis of the suspension strut 1 120.

[0272] A clutch arrangement 140 in the form of an overrun bearing 144 is provided on the axle of each wheel which allows power to be transmitted from the drive arrangement via the transmission to the wheel hub assembly, but not in reverse.

Fifth embodiment

[0273] A fifth embodiment of a drive system 100 is shown in figure 11. The drive system includes a pair of power sources 150 a & b in the form of batteries. Each battery 150 is electrically connected to a drive arrangement 1 10 a & b, including an electric motor 1 12 a & b, respectively. Each of the drive arrangements 1 10 includes a shaft 1 16 a & b, on which a drive sprocket 1 14 a & b is securely mounted.

[0274] Each of the drive sprockets 1 14 a & b is operatively coupled to a second sprocket 1 14 c & d via a flexible linkage in the form of transmission chains 130 a & b.

[0275] The second sprockets 1 14 c & d are securely mounted on shafts 124 a & b to rotate therewith. A third sprocket 1 14 e & f is mounted on each of the shafts 124 a & b, at an opposed end from the second sprockets 1 14 c & d. Each of the third sprockets 1 14 e & f are securely connected to their associated shafts 124 a & b to rotate therewith, and operatively coupled to an associated fourth sprocket 1 14 g &h via transmission chains 130 c & d.

[0276] Fourth sprockets 1 14 g &h are each mounted to a wheel hub assembly 1200, to rotate with the wheel (not shown) of a trailer 1000.

[0277] A clutch arrangement in the form of a centrifugal clutch (not shown) is provided on the axle of each wheel which allows power to be transmitted from the drive arrangement via the transmission to the wheel hub assembly in two directions, but also allows the clutch to disengage when the wheels (pulled by the vehicle) drive the transmission arrangement at an angular velocity that is too high for the transmission and drive arrangement to keep up with. .

[0278] It is envisaged that, by providing individual drive arrangements 1 10 and transmissions 120 for each wheel, the direction in which a trailer is driven by the drive arrangements 1 10 can be controlled. It is further envisaged that the control unit can be configured to drive the individual wheels at differing speeds, thereby allowing the trailer to be steered during alternative uses, for example moving the trailer 1000 around a campsite where vehicles 2000 are not allowed access.

Sixth embodiment

[0279] In a sixth embodiment shown in figures 12 and 13, a flexible linkage in the form of a transmission chain or belt is not utilised. Instead, the drive system 100 operates as a shaft driven system. The drive system 100 includes a drive arrangement 1 10, including an electric motor 1 12, that is mounted to a trailer frame 1 100 and a transmission 120. The transmission 120 includes a driveshaft 138 that is connected to a differential 170. The electric motor 1 12 is connected to the driveshaft 138 via a first universal coupling 135. The driveshaft 138 is connected to the differential 139 via a second universal coupling 137. The driveshaft 138 includes a spline portion 133 that allows the length of the driveshaft 138 to vary without restricting the transmission of torque through the driveshaft 138. The spline portion 133 allows the length of the driveshaft 138 to vary in operation when the suspension of the trailer allows the wheel axle 1300 to move relative to the trailer frame 1 100.

[0280] Differentials 170 are well known in the art, and one embodiment of a differential configuration is shown in figure 14, including a pinion gear 171 coupled to the driveshaft 138 to rotate with the driveshaft 138, the pinion gear 171 rotatably engaging with a ring gear 172, with the pinion gear 171 rotating about a pivot axis that is substantially transverse to the pivot axis of the ring gear 172.

[0281 ] The ring gear 172 includes a pair of extension formations 173 extending from the ring gear, on which spider gears 174 are rotatably mounted about a pivot axis that is substantially transverse to the pivot axis of the ring gear 172. The spider gears 174 are disposed on opposed directions, and each engage with a pair of side gears 175 that are also disposed in opposed directions. Each of the side gears 175 are security mounted to wheel axles 1300, which drive rotation of the trailer wheels.

[0282] It is further envisaged that, where the drive system 100 is adapted to drive movement of a wheel hub assembly 1200, for example via a wheel axle 1300, the wheel hub assembly can be provided with a freewheel hub arrangement 176 (shown in figure 15) that allows the wheel to be engaged or disengaged from the wheel axle 1300. Such a freewheel hub arrangement 176 could be applied to any of the embodiments shown.

[0283] It is also envisaged that such a freewheel hub assembly can also be provided on any of the axles, or in association with any of the gear cogs described above.

[0284] If a free wheel hub arrangement is provided on the wheel axle, it allows the entire transmission to be disengaged from driven movement of the wheel (as the trailer is being pulled by the vehicle) until a tough obstacle or terrain is encountered, wherein the operator of the vehicle may lock the freewheel hub to engage the transmission with the wheel to allow the drive system to drive the wheels to negotiate the obstacle or terrain.

[0285] Freewheel hub arrangements 176 are known and are in common use in four- wheel drive vehicles, and can be configured between an engaged condition and a disengaged condition by movement of an actuator (not shown) . Movement of the actuator can be by manual or electrical means, and can preferably be performed remotely from the towing vehicle.

[0286] It is envisaged the user of a drive system 100 would move the freewheel hub arrangement to its engaged condition before attempting to cross difficult terrain, so that the drive system 100 is able to drive the wheels 1400 of the trailer 1000. Once the difficult terrain has been overcome, the freewheel hub arrangement would be moved to its disengaged condition, to ensure that movement of the wheels 1400 does not constantly drive movement of the transmission 120, or a portion thereof, thereby reducing wear.

Seventh embodiment [0287] A further embodiment is shown in figure 15 In this embodiment, an electric motor 1 12 and transmission 120 are disposed at or towards a wheel hub assembly of preferably each wheel, so that the drive arrangement 1 10 engages with a transmission 120 that is securely mounted on the wheel hub assembly 1200.

[0288] As shown in figure 15, the electric motor 1 12 is configured to drive a driveshaft 1 16. A clutch 140 in the form of an overrun bearing 144 is mounted on the driveshaft 1 16 to rotate with the driveshaft. The overrun bearing includes a first portion 144a and a second portion 144b that are movable relative to each other. The first portion 144a is mounted to the driveshaft 1 16. The second portion 144b is securely mounted within and preferably keyed with, a pinion gear 139 to rotate with the pinion gear. The pinion gear 139 engages with, and drives the rotation of, a ring gear 138. The ring gear 138 is mounted on, and rotates with the wheel hub assembly 1200 of the trailer.

[0289] It is envisaged that this embodiment can be used to replace the wheel hub assembly of a normal trailer wheel, so that a drive system according to the present invention can be retrofitted to existing trailers.

[0290] In this embodiment, the drive system 100 can include a braking arrangement (not shown) for braking the wheels of a trailer, where the wheel hub assembly that has been replaced included such a braking arrangement. In this way, the drive system 100 can be used to retrofits to an existing trailer, replacing the entire wheel hub assembly and braking arrangement of the trailer.

[0291 ] In an alternative embodiment, it is envisaged that the clutch could be an electrically operable clutch that is actuated by the control system to engage and disengage a drive arrangement from its associated trailer wheel. This is discussed in more detail below.

[0292] It is further envisaged that the wheel hub assembly can include a freewheel hub arrangement 176, whereby the wheel 1400 can be disengaged from movement of the wheel hub assembly, and can be engaged for use in specific circumstances, such as a length of particularly rugged terrain, or the like. As discussed above, when the freewheel hub arrangement 176 is disengaged, this will prevent the rotation of the wheels from driving the transmission 120, and engage the transmission with the wheel when the freewheel hub arrangement 176 is engaged. During normal operation on the roads, when additional drive from the trailer wheels is not required, it is envisaged that the freewheel hub arrangement 176 will be disengaged, allowing the wheels 1400 to rotate freely without driving the transmission or the drive arrangement. [0293] When the freewheel hub is engaged, rotational movement of a wheel translates into rotational movement of the wheel hub assembly 1200, and vice versa. Accordingly, when there freewheel hub assembly 176 is engaged, and the drive system 100 causes the wheel hub assembly 1200 to rotate, this will also cause the wheel 1400 to rotate, driving movement of the trailer 1000 over the ground. However, when the trailer is being pulled over the ground to rotate the wheel at a velocity that is greater than that being imparted to it by the drive system 100, the clutch 140 will disengage the rotational movement of the wheel hub assembly 1200 from the drive arrangement 1 10, protecting the drive arrangement.

Eighth Embodiment

[0294] An eighth embodiment of a drive system 100 is shown in figure 16. In this embodiment, an electric motor 1 12 that is mounted to the trailer frame 1 100 drives a shaft 1 16, on which an overrun bearing 144 is mounted. A first gear 123a is in turn mounted on the overrun bearing, and engages with second gear 123b. The second gear 123b is mounted to the same idler shaft 131 as a friction coupling 125 to rotate with the friction coupling 125. Friction coupling 125 is configured for direct engagement with the tread of a tire 1410 of a wheel 1400 of a trailer 1000.

[0295] When actuated by the control unit 180, the electric motor 1 12 will cause the driveshaft 1 16 to turn, thereby turning the overrun bearing 144, causing the first gear 123 a to rotate with the driveshaft 1 16. Rotation of the first gear 123a will cause rotation of the second gear 123b. Rotation of the second gear 123b will in turn cause rotation of the friction coupling 125, being mounted on the same shaft. Rotation of the friction coupling 125 will cause rotation of the wheel 1400 by virtue of the friction engagement of the friction coupling 125 with the tire 1410.

[0296] When the wheel 1400 is driven by trailer being pulled by the vehicle over the surface of the ground at an angular velocity that is faster than the electric motor is driving the friction coupling 125 at, the friction coupling 125, and in turn the second gear 123b and first gear 123a will move at a faster angular velocity than the shaft 1 16, causing the overrun bearing 144 to disengage the first gear 123a from the shaft 1 16.

Gearbox

[0297] In a further embodiment shown in figure 17, it is envisaged that one or more gearboxes 160 can be included at any point along the transmission 120. A gearbox 160 can be included upstream and/or downstream of the clutch 140. The gearbox preferably includes an input shaft and an output shaft, and is configured to change the gear ratios between the input and the output shafts in a known fashion.

[0298] The gear ratios may be configured in distinct stepped ratios, or may be configured as a continuously variable transmission gearbox, that allows for an infinitely variable set of ratios within a range. Such gearboxes are known, and a discussion of the internal operation of such gearboxes is considered beyond the scope of the specification. In this way, the threshold angular velocity of the centrifugal clutch 140 can be dictated by the gearbox.

[0299] It is further envisaged that the gear ratios of the gearbox or gearboxes may be controllable by a control unit 180 as will be described in more detail below.

Ninth Embodiment

In a ninth embodiment shown in figure 17, a pair of electric motors each drive a transmission 120. The transmissions 120 each include an electronic clutch 146 and a pair of gearboxes 160, preferably in the form of continuously variable gearboxes, although gearboxes having a set of discrete drive ratios are also envisaged in alternative embodiments.

In each transmission, one gearbox 160 is located towards the side of the drive arrangement (hereinafter“upstream”), while another gearbox is located towards the side of the wheels (hereinafter “downstream”). It is envisaged that in an alternative embodiment (not shown) only a single gearbox 160 may be provided for each of the transmissions 120.

Further, the drive system 100 includes a control unit 180. The control unit is configured and adapted for controlling both of the electronic clutches 146. The electronic clutches can be actuated to engage and/or disengage under control by the control unit 180, for example by using an electrical actuators such as a solenoid or the like.

The control unit 180 is also configured to control operation of the gearboxes 160. The gearboxes 160 are configured to be controlled by a control unit 180 in a manner as will be described in more detail below.

The gearboxes 160 are used to ensure that the drive from the drive arrangement can be provided to the wheels at a wide variety of speeds, and in a wide variety of situations.

The electronic clutches are used to ensure that the upstream transmission is disengaged from the downstream transmission when the difference in angular velocities is becoming too great for the drive arrangement to handle. In this way, the electronically controlled clutch 146 serves the same function as a freewheel clutch and/or a centrifugal clutch - to protect the drive arrangement.

Control unit

[0300] As shown in figure 13 and 17, the drive system 100 includes a control unit 180 that includes a receiver (not shown) that is capable of receiving signals from a wireless controller 182, for example that may be located within the towing vehicle 2000. It will be appreciated by a person skilled in the art that the control unit described with reference to figure 13 could be equally applied to any other embodiments of a drive system or trailer.

[0301 ] The control unit 180 can be electrically connected up to the towing vehicles electrical system via the towbar electrical system. The control unit 180 can receive signals from sensors on both the trailer as well as the towing vehicle. For example, the control unit 180 can receive an indication of when wheel slip occurs on the towing vehicle, and on detection of such an event, can actuate drive to the trailer wheels.

[0302] Where the control unit 180 is capable of controlling operation of the gearbox, it is envisaged that the control unit can be adapted for receiving signals from sensors on the trailer that give an indication of the angular velocity of the transmission both upstream and downstream of the clutch. The control unit 180 can further be adapted for selecting an appropriate gear ratio in the gearbox 160 or gearboxes to match the angular velocity of the transmission to either side of the clutch.

[0303] In this regard, it is envisaged that the control unit 180 could further operate the braking arrangement of the trailer to match the angular velocity of the downstream transmission with the angular velocity of the upstream transmission.

[0304] The control unit 180 could further select appropriate gear ratios in the gearbox or gearboxes 160 to slow the trailer and thereby supplement braking by the brakes of the trailer, for example on a steep downhill.

[0305] In another use, the control unit 180 can be configured for actuating the braking arrangement and/or clutch to engage the transmission when the drive arrangement is not actuated and the vehicle is not coupled to the trailer, thereby preventing theft. [0306] In another use, the control unit can control the drive arrangement and/or gearbox to operate at a particular angular velocity corresponding to a low speed, and actuate the clutch to engage the drive arrangement with the wheels, in order to provide a braking effect or drag on a vehicle traversing down a steep incline. In this way, the braking effect caused by the towing vehicle (which may be using brakes or transmission braking) can be supplemented by the trailer.

[0307] The control unit 180 can include sensors (not shown) for sensing various operating parameters of the drive system 100, including voltage, current, angular velocity, strain, frequency of rotation, or the like.

[0308] The control unit 180 also includes a transmitter (not shown) for transmitting signals received from the sensors to a display unit 184, for example located in the towing vehicle 2000. In a preferred embodiment, the wireless controller 182 can include a built- in display unit 184 such as a touchscreen for displaying the transmitted operational parameters sensed from the sensors to a user in the towing vehicle. Alternately, it is envisaged that existing display units in the vehicle could be used for the display of such information.

[0309] It is further envisaged that the control unit 180 can be configured to control the speed at which the drive system 100 drives the trailer wheels, which can be set to be driven at predetermined speeds.

[0310] Further, the control unit 180 can be configured to drive either or both of the trailer wheels, where individual wheels are capable of being driven by the drive system 100, for example using the embodiment shown in figure 1 1 . It is further envisaged that the control unit 180 can be used to move the freewheel hub arrangement between its engaged condition and disengaged condition.

[031 1 ] The controller 182 can further include a user input interface, such as a touchscreen, that allows a user to set inputs, switch the system on or off, and/or adjust the torque and/or speed at which the drive arrangement is driving the transmission.

[0312] It is further envisaged that the control unit 180 can control disengagement of the clutch 140 electronically. The angular velocity of the wheels and/or transmission can be monitored by sensors, and the control unit 180 can be configured to send a signal to an electronic clutch arrangement to disengage the drive arrangement from the wheels in the event that angular velocity exceeds a predetermined threshold. However, this embodiment is not preferred as it will increase the complexity of the drive system 100. [0313] The control unit 180 can be used to control operation of the electric motors, electronic clutch 146, braking arrangement of the trailer, and/or gearboxes 160 according to one of a plurality of pre-set operating characteristics to ensure safe operation of the drive system in a wide variety of modes of operation.

[0314] For example, in a first mode, the control unit can be used to control drive to the wheels at low speeds (for example between 1 km/h and 20 km/h), in a forward direction, and at high torque, to facilitate the traverse of the vehicle and the trailer through rough terrain (such as mud or steep inclines) obstacles by supplementing the drive of the towing vehicle. This drive can be provided in a forward or backwards direction.

[0315] In a second mode, the control unit can be used to control drive to the wheels at mediums speeds (for example between 10 km/h and 40 km/h), in a forward direction, and at low torque, to facilitate the traverse of the vehicle over sand (for example on a beach).

[0316] In a third mode, the control unit can be used to control operation of individual trailer wheels at low speeds (for example between 1 km/h and 10 km/h), and in particular directions to facilitate self driving and steering of the trailer independently of the vehicle.

[0317] In a fourth mode, the control unit can be used to control operation of the wheels in a forward direction, at low torque and at high speeds (for example between 60 km/h and 120 km/h) to facilitate the traverse of a vehicle up a low gradient on a motorway.

[0318] The control unit is also preferably configured to coordinate drive to the trailer wheels with operation of the towing vehicle’s accelerator, and cut drive to the trailer wheels when the towing vehicles brakes are operated. It is envisaged that the control unit may be connected to the vehicle via the electrical connectors associated with the towing vehicle’s towbar.

[0319] The control unit 180 can include program schedules that facilitate operation in particular modes as described above, each mode of operation being pre-set for causing the control unit to operate any of the drive arrangement, clutch, gearbox and brakes in accordance with particular operating characteristics as described above. The programed schedules can be pre-set to facilitate different modes of operation of the system 100 including variation of the speed and/or auxiliary power provided to the wheel providing the advantage of using the system 100 under specific pre-settings for specific conditions and/or purposes. For example, one program schedule could include a sand driving schedule, wherein torque transmitted through the transmission from the drive arrangement would be restricted to prevent the transmission of torque above a certain threshold, to thereby prevent the trailer wheels from digging themselves in. Similar program schedules could be included for alternative terrain such as mud, snow, or ice. Other schedules could include a high-speed motorway driving schedule wherein the gearbox ratios are set for providing forward drive to the wheels via clutch at suitable angular velocities, with the clutch disengaging the drive arrangement before the angular velocity of the wheels picks up to a speed that the drive arrangement is not able to handle.

[0320] It is further envisaged that a user input, for example in the form of a joystick or similar directional control device, can be provided, so that a user is able to control drive to wheels to either side of the trailer (on those embodiments where drive to independent wheels is envisaged), thereby controlling the direction of movement of the trailer.

[0321 ] The display unit could be any one or more of a liquid crystal display (LCD), light-emitting diode (LED) display, organic light-emitting diode (OLED) display or thin-film- transistor (TFTD) display. Alternatively, it could be a push button switch board having a button to switch on/off the system 100 and a light showing on/off status of the system 100. In one embodiment, the control unit 180 will be configured to allow for the termination of the operation of the system 100 at any given time. This functionality can be actuated remotely of the trailer, for example via the wireless controller 182 from within the towing vehicle.

[0322] In one embodiment, it is further envisaged that the control unit could be in the form of a mobile phone on which control software has been downloaded, the mobile phone communicating with the control unit via a wireless communications protocol such as Bluetooth™.

[0323] In an alternative embodiment (not shown), it is envisaged that remote controller having a long control cable may be provided instead of a wireless controller.

[0324] In an alternative embodiment (not shown), it is envisaged that the drive arrangement need not include an electric motor, but could instead be a driven coupling, such as a shaft coupling, that is configured to be coupled to an external drive externally of the trailer 1000, for example a driven rotating shaft on the towing vehicle, such as may be found on tractors or the like. The driven coupling will then be driven by the shaft to rotate with the shaft.

[0325] The system 100 can further include an indicator or an alert for notification (not shown in the Figures provided). The indicator and/or alert is beneficial for informing the driver of the powered vehicle and/or operator of the system for attracting attention whom may be nearby. For example, if the system 100 is turned on, a sound alert can notify/alert surrounding people when the trailer is moving backward/ forward.

[0326] In one embodiment, the control unit can include an electrical interface, for example in the form of a plug 186 that is able to be wired into the wiring harness of the trailer, for electrical connection to the towing vehicle as shown in figure 13. The control unit can be configured to control the drive system 100 automatically on receiving a signal indicative of an event occurring on the towing vehicle. For example, the control unit can be configured to actuate the drive arrangement to drive the trailer if wheel slip is detected in the towing vehicle. In another example, the whole unit can be configured to control the drive arrangement 1 10 to stop driving the trailer wheels if it detects that the towing vehicle brakes have been applied.

[0327] As mentioned previously, the drive system 100 can include a braking arrangement (not shown), which can be configured for slowing angular movement of the wheels directly, or indirectly via the transmission arrangement. The control unit can be configured for automatically actuating the braking arrangement, for example when the vehicle is uncoupled from the trailer.

In use

[0328] The drive system 100 is adapted to provide assistive motive force to the wheels of the trailer in adverse road conditions or rough terrain, for the purposes of not getting bogged down over short difficult stretches of terrain, or for providing assistance on normal roads.

[0329] More advantageously, the drive system 100 is preferably adapted for mounting to a portion of the frame and/or suspension strut of the trailer in a manner that does not change the original ground clearance of the trailer. This will facilitate the towing of the trailer through uneven roads and over obstacles.

[0330] A typical example of use of the drive system 100 would be on a muddy track, where a particularly deep section of mud is encountered, where the driver of the towing vehicle would not be confident in the ability of the towing vehicle to pull the trailer through the section without getting bogged down. Before attempting to traverse the section, the vehicle would be stopped, and, where a freewheel hub arrangement is provided on the wheels, these would be engaged, thereby coupling the drive arrangement 100 and the wheels in a manner that allows the wheels to be driven by the drive arrangement 100. [0331 ] A user of the system would then attempt to traverse the section, and, if the speed of the vehicle is slowing, and the user believes that the towing vehicle and trailer would become bogged, the controller 182 would be used to actuate operation of the drive system 100, to thereby cause the drive arrangement to drive the trailer wheels, providing additional motive assistance. It is also envisaged that the controller 182 could be used to actuate operation of the drive system 100 before attempting to traverse the deep section.

[0332] It is further envisaged that, where drive to independent wheels is provided, this can be used to control the direction of movement of the trailer, even when not coupled to a towing vehicle. In this way, the drive system 100 can be used to manoeuvre and position a trailer 1000, for example in a campsite where towing vehicle access is not available.

[0333] In addition, the drive system allows for a method of maneuvering a trailer, in situations where backing up or manoeuvring the tow-vehicle and/or trailer attached is difficult, particular for drivers that are untrained at backing with trailers. Where an overrun bearing is used as a clutch, it is envisaged that reversing of the trailer using the control unit would not be possible, unless the overrun bearing could be locked. However, where a centrifugal clutch is provided, manoeuvring would be possible at low speed.

Interpretation

[0334] It should be appreciated that in the above description of example embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, any features or embodiments shown or described can be grouped with any other embodiments shown or described.

Different Instances of Objects

[0335] As used herein, unless otherwise specified the use of the ordinal adjectives “first”,“second”,“third”, etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner. Different Positioning and/or Orientation

[0336] As used herein, unless otherwise specified the terms“upper”,“lower”,“right”, “left”,“rear”,“front”,“vertical”,“horizont al”,“interior”,“exterior”, and derivatives thereof shall relate to the invention with reference to all figures accompanied with the specification. However, it is to be understood that the invention may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific parts and/or the system illustrated in the accompanied figures and described in the specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not be considered as limiting, unless the claims expressly state otherwise.

[0337] Further, it is to be understood that discussion of a particular feature of component extending in or along a given direction or the like do not mean that the feature or component follows a straight line or axis in such a direction or that it only extends in such direction or on such a plane without other directional components or deviations, unless otherwise specified.

Specific Details

[0338] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0339] The terms“a” and“an” refers to one or more, unless expressly specified otherwise.

[0340] The term “trailer” includes, but is not limited to a caravan, motor home, recreational vehicle, trailer and/or camper trailer.

[0341 ] In the present specification, the term“connected”, or a similar term, such as “functionally connected”, may mean that two or more elements and/or parts and/or features are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other. [0342] The term“power source” refers to a source of power, includes but not limited to a battery, power supply current source and/or voltage source, as well as external sources of electrical power or mechanical power.

[0343] The term “communication means”, includes, but not limited to means of sending or receiving information, and/or transmission of information.

[0344] In the present specification, the term“means” may refer to singular or plural items and are terms intended to refer a set of properties, functions or characteristics performed by one or more items having one or more parts.

[0345] The term“information” or“data” includes data and data sets that may be analyzed computationally to reveal a demand, operation and action associated with operation of the system.

[0346] It will be appreciated by those skilled in the art that any information and/or data transmission referred to above could be in the form of telecom or Datacom, and could be sent via wire-based (optical fibre, cable, etc) or wireless services.

[0347] As used herein, except in the claims, the words“and” and“or” are each defined to also carry the meaning of“and/or”.

Comprising and Including

[0348] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word“comprise” or variations such as“comprises” or“comprising” are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[0349] Any one of the terms: including or which includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising. Scope of Invention

[0350] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention.

[0351 ] Where preamble of a claim recites a purpose, benefit or possible use of the claimed invention, it does not limit the claimed invention to having only that purpose, benefit or possible use.

[0352] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Industrial Applicability

[0353] It is apparent from the above, that the system and method described are applicable to the trailer and/or motor vehicle industries.