GB2510574A

GB2510574A - A drive unit for trailers

Info

Publication number: GB2510574A
Application number: GB201302152A
Authority: GB
Inventors: Peter Nickson
Original assignee: DIRECT DRIVE MOVER
Current assignee: DIRECT DRIVE MOVER
Priority date: 2013-02-07
Filing date: 2013-02-07
Publication date: 2014-08-13
Anticipated expiration: 2033-02-07
Also published as: GB2510574B; GB201302152D0

Abstract

The present invention provides a drive apparatus for a trailer with at least one wheel having an accessible axle wheel hub. The apparatus comprises a driver arranged in use to be mounted on said wheel hub, in which said driver comprises a portion dimensioned to be secured to the wheel hub. The apparatus further comprises a circumferential ring gear provided on a first end of the portion of the driver and a base at a second end of the portion of the driver, the base comprising a means to secure to the wheel hub. The apparatus further comprises a drive unit arranged in use to be mounted on the trailer comprising an electric motor and shaft driven by the motor having a drive gear at an end of the shaft. The drive gear is moveable relative to the trailer in a direction substantially parallel to the axis of the wheel hub in order to engage with the ring gear to transmit force from the drive unit to the hub drive.

Description

A drive unit for trailers

Field of the Invention

The present invention relates to a drive apparatus for caravans and trailers usable to move the caravan or trailer when disconnected from a towing vehicle, and in particular to an electrically powered drive apparatus that may be retrofitted to a caravan or trailer.

Background

Trailers such as caravans are difficult to move when disconnected from the towing vehicle, for example when parking in a confined space. Devices for moving trailers are known, often battery powered and using electric motors fixed to the trailer, typically to the trailer chassis. Prior art devices require permanent fixture of driving units including motors and in some cases, modification to the trailir chassis. Many devices drive the wheels using a friction roller in contact with the tyres on the wheels, the roller being movable into position when the driving device is in use and moved away from the wheels at other times. Such devices have well known problems including poor drive when the tyres are wet or muddy, which is often the case on caravan camp ground for example. They also impose stress and wear on the tyre.

Devices are known that drive the wheels using gears. These are advantageous, but the prior art designs have drawbacks, including the need for a permanent modification of the wheel hubs to provide gear means, and the need for a drive unit to be permanently fixed to the trailer chassis. No drive apparatus exists that uses gear drive for reliability, and is easily fittable to a trailer by a non-skilled user and is again removable if necessary, and is adjustable to fit a wide range of trailer types and sizes. It is an object of the present invention to provide such a drive apparatus.

Prior Art

Accordingly a number of patent applications have been filed in an attempt to resolve the problem or similar, including the following: EP233601 1 discloses a vehicle drive device comprises a support fixed to a chassis of the vehicle, a moving carrier holding a drive motor, a gear box of the drive motor, bearings and a roller, wherein the drive motor, the gearbox, the bearings and the roller are connected to each other in sequence to drive the roller to rotate, and the roller can act upon a tyre of the vehicle to rotate the wheel of the vehicle by the rotary movement of the roller. The vehicle drive device further comprises a servo-drive S device connected to a moving carrier through a linkage to drive the moving carrier to move along a circular arc-shaped path, so that the roller can be shifted between a rest position and an operating position. The vehicle drive device according to the present invention drives the moving carrier to move along a circular arc-shaped path so that the roller moves toward the wheel (the tyre) of the vehicle along a circular arc-shaped path which is located in a plane extending substantially perpendicularly to the axis of rotation of the wheel of the trailer when the auxiliary drive unit is mounted on a trailer. This will cause the roller to press against the tyre from an obliquely downward direction, effectively increasing the pressing force to the tyre.

EP2028086 discloses an auxiliary drive for a caravan or other trailer. This auxiliary drive comprises a motor with a reduction gear and a drive element such as a drive roller. This can be displaced with respect to the frame of the trailer towards the wheel in order to drive the latter in a rotating manner. It is proposed to mount a power take-off on the drive unit comprising a motor reduction gear and drive element. This may comprise a rotatably driven shaft on which a gear wheel can optionally be mounted.

This may be used, for example, to control the displacement of the unit comprising a motor reduction gear and drive element with respect to the frame. However, it is also possible to drive other systems which require mechanical work, such as extending legs of a trailer in order to stabilize these in a specific position.

EP2017147 discloses a system having a carrier fastened to a vehicle trailer in a region of a wheel, and a bearing carriage slidably supported at the carrier. A drive motor arranged at the bearing carriage rotatably drives a friction roller, which is engageable to the wheel for the accessory drive of the wheel. The accessory drive for displacement of the bearing carriage for the deliver of friction roller is transferred at the wheel from the drive motor over a selectively activatable gear arrangement.

EP1894522 provides apparatus for moving a trailer. The apparatus has at least one drive unit a drive unit mounting and an actuation means associated with the, or each, drive unit. The, or each, drive unit includes a roller for frictionally engaging a wheel of a trailer and a motor for driving the roller. The drive unit mounting is suitable for securing the drive unit to a trailer, the, or each, drive unit is movably coupled to the drive unit mounting. The, or each, actuation means is coupled to the drive unit mounting such that, when actuated the actuation means causes the roller with which it is associated to move relative to the drive unit mounting along a translational axis so that, in use, the actuation means can be actuated to move the roller between an engaged position, in which the roller is engaged with the wheel of a trailer, and a released position, in which the roller is not engaged with the wheel of a trailer. The or each drive unit comprises a gear arrangement including an actuation means arranged for rotational movement about an axis of rotation which is non-parallel and non-collinear with the translational axis, wherein rotational movement of the actuation means causes the roller to move relative to the drive unit mounting.

The above devices are representative of most of the prior art devices that aim to provide drive for trailers, and all provide drive means having a roller that moves to engage with the rolling surface of a tyre to move the trailer and have the disadvantages of poor drive reliability inherent in that arrangement.

GB2305408 provides a manoeuvring unit for a caravan that comprises a bi-directional electric motor connectable to the battery system of the caravan and arranged to drive a road wheel. The electric motor may drive the wheel through reduction gearing with an output pinion engaging gear teeth provided on the brake drum. The pinion is disengaged from the gear teeth when drive is not required. Belt-and-pulley gearing may be used instead. A wheel at each side may be driven.

This device provides a gear drive but relies on replacing the existing components of the trailer with new ones, including a replacement brake drum having an external ring gear, fitting a motor to the chassis inboard of the wheel, and providing means mounted on the chassis for the output pinion to be supported and moved. This does not achieve the objective of a simple retrofittable drive apparatus suitable for a wide range of trailer types.

EP1840019 provides an auxiliary drive for a trailer such as a caravan. Said drive consists of a drive unit with a gearwheel. Through linear movement of the drive unit relative to the chassis, said gearwheel can be brought into engagement with a ring gear filled either on the brake drum of a wheel of the vehicle or on an auxiliary part such as a covering drum fitted pver said brake drum, The ring gear preferably lies in a plane outside the plane bounded by the inside of the wheel.

This device overcomes some disadvantages of the previous disclosure above but requires one or more drive units separately mounted on the trailer chassis in such a way that they may be moved forward and back in order to engage with the ring gear.

This is not a design that can be fitted by an un-trained person and the open gearing, on an external ring gear, is liable to dirt covering and damage.

Summary of the Invention

In the following, by trailer is meant any towable non-powered vehicle including caravans, boat trailers and trailers for carrying domestic, industrial, agricultural or other goods.

According to the present invention there is provided a drive apparatus for a trailer with at least one wheel having an accessible axle wheel hub, in which the apparatus comprises: a driver arranged in use to be mounted on said wheel hub, in which said driver comprises a portion dimensioned to be secured to the wheel hub, a circumferential ring gear provided on a first end of the portion of the driver and a base at a second end of the portion of the driver, the base comprising a means to secure to the wheel hub; and a drive unit arranged in use to be mounted on the trailer comprising an electric motor and shaft driven by the motor having a drive gear at an end of the shaft, the drive gear being moveable relative to the trailer in a direction substantially parallel to the axis of the wheel hub in order to engage with the ring gear to transmit force from the drive unit to the hub drive.

Preferably first and second drivers and drive units are provided to drive a wheel on each side of the trailer, wherein said drivers and units may be controlled independently or simultaneously to form the apparatus.

Preferably the ring gear is arranged in use to be provided on the inner or inner circumference of the driver. In a preferred embodiment when the driver is filled to the wheel hub the ring gear lies within the plane of the outer extent of the tyre mounted on the wheel.

The portion advantageously comprises a drum arrangement arranged in use to enable stable and effective securement of the driver to the wheel hub in direct replacement and facsimile of the wheel.

In preferred embodimerts the means to secure the driver, or drum or portion to the wheel hub, or axle hub, comprises a plurality of bolt holes evenly spaced around a circle concentric with the centre of the driver and adapted to receive bolts mounted on the axle/wheel hub.

The ring gear on the inner circumference of the wheel may be protected from dirt from the surroundings of the wheel and means the driver is easier to handle in fitting by an untrained user! and therefore is a preferred design over those with an external ring gear.

In preferred embodiments the shaft is movable by the motor in order to engage the ring gear. Preferably the motor comprises gear means adapted to move the shaft forward parallel to the axis of the shaft when the motor is energised, and to rotate the shaft about its axis to provide drive force via the shaft gear.

In an alternative embodiment the drive unit comprises actuation means to move the drive unit relative to the trailer in order for the shaft gear to engage the ring gear.

In a preferred embodiment the drive apparatus further comprises a drive unit mounting bar adapted to be mounted on the trailer and having a first drive unit mounted at a first end of the mounting bar and a second drive unit mounted at the second end of the bar. Preferably the mounting bar comprises fixtures adapted to mount the mounting bar on a common axle joining the first and the second wheel hubs. In a preferred embodiment the mounting bar comprises means to set the spacing apart of the drive units in order to adapted the apparatus to trailers of different width. In a preferred embodiment the mounting bar has a telescopically adjustable length. Preferably the mounting bar comprises one or more hollow tubing sections adapted to fit together telescopically and comprising fixing means to fix a first section relative to a second.

In this way, in use the driver is placed over the wheel hub, the wheel being mounted onto the driver. The wheel then turns the driver and the wheel hub on the axle of the wheel hub. The drive unit may be mounted on the trailer chassis and while towing the shaft gear is disengaged from the ring gear. When the trailer is to be moved by the drive apparatus the shaft gear is moved in a direction substantially parallel to the axis of the wheel hub and axle in order to engage the ring gear on the driver. The drive unit motor is then actuated in order to turn the wheel and move the trailer.

In a preferred embodiment the motor comprises gear means adapted to move the shaft forward parallel to the axis of the shaft when the motor is first energised, and then to rotate the shaft about its axis to providedrive force via the shaft gear. Such arrangements are known for example in petrol or diesel engine starter motors.

In an alternative embodiment the drive unit comprises a second motor adapted to move the drive unit relative to the wheel hub in a direction substantially parallel to the axis of the wheel hub in order to bring the shaft gear into engagement with the ring gear.

In the case where a drive unit mounting bar is provided, the mounting bar may be attached to the trailer transversely parallel to the axis between the wheels so presenting a first drive unit to a first wheel and the second drive unit to the second wheel. In some embodiments the mounting bar may be attached to an axle. In each case in preferred embodiments the drive unit(s) may be retrofitted to the trailer without the need for modification to the trailer or for permanent attachment of the apparatus to the trailer, in contrast with moving devices pf the prior art.

Preferably the apparatus comprises a first drive unit for a wheel at a first side of the trailer and a second drive unit for a wheel at the opposite side of the trailer and a control means to actuate each drive unit separately. In this way the control means may actuate both drive units to move forwards and backwards and one drive unit to a differently from the other to cause the trailer to turn. For example, a first drive unit may be driven at a different speed from the second, or in reverse relative to the second.

The control means may comprise wired control means, to be located on or about the trailer, for example at the trailers hook-up, so as to localise control and instructions when pulling.

In preferred embodiments the control means comprises remote control means, for example using RF, infrared or cable communication means as known in the art.

In a preferred embodiment the driver further comprises a plurality of bolts evenly spaced on a circle concentric with the centre of the driver and spaced apart from the bolt holes, the bolts being arranged in use to pass through bolt holes in the wheel. In this way the driver may be bolted to the wheel hub, and the wheel may then be bolted using a second set of standard wheel nuts to the driver.

In a further preferred embodiment the apparatus comprises a torsion bar. Preferably the torsion bar is provided as part of the mounting bar. Preferably the torsion bar forms part of the linkage between the first and the second drive units.

According to a third aspect the invention provides a trailer comprising a first and a second wheel on each side of the trailer and a drive apparatus as described above mounted on the trailer.

According to a fourth aspect the invention provides a method of moving a trailer comprising the steps of: fitting a driver as described herein to a wheel hub on the trailer and fitting the wheel over the driver; and causing the shaft gear to engage the ring gear and powering the drive unit motor to drive the ring gear.

In a preferred embodiment the method comprises the further steps of fixing to the trailer a drive unit mounting bar having a drive unit provided at each end of the bar. Preferably the mounting bar is fixed to an axle of the trailer.

In a preferred embodiment the method comprises the further step of adjusting the length of the mounting bar to suit the width of the trailer.

The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing from the scope of invention.

With respect to the above description then, it is to be realised that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.

Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Brief Description of Figures

Figure 1 shows a front view of an embodiment of the invention Figure 2 shows a top view of the embodiment shown in figure 1 Figure 3 shows an isometric view of the embodiment shown in figure 1 Figure 4 shows a front view of a driver forming part of an embodiment of the invention Figure 5 shows a rear view of the driver as shown in figure 4 Figure 6 shows an isometric view of a driver forming part of an embodiment of the invention.

Detailed Description of Figures

Referring to figures 1 to 3, the apparatus comprises a first drive unit 12 and a second 14, each comprising a motor within the drive unit and a shaft 16 having a shaft gear 18, the drive unit comprising means to move the shaft 16 parallel to the axis of the shaft and to rotate the shaft. The drive units are mounted on a mounting bar 20 comprising two larger outer box sections 22 and a central smaller box section 24, the outer box sections being adapted to fit over the ends of. the central box section and to.

slide along it to provide a telescopic length adjustment means for the mounting bar.

The position of the box sections and hence the length of the mounting bar and spacing of the drive units is lockable by locking means 30, for example comprising a bolt and screw thread. The apparatus comprises a control means housed in a control box 28, in this embodiment mounted on the mounting bar and connected to the drive units by cabling 29. The mounting bar comprises fixing means 26 adapted to fix the mounting bar to the trailer between the wheels such that when extended the shaft gears 18 engage the ring gear of the driver s when in place on the wheel hubs.

The fixing means may comprise flat plates and slots or threaded nuts mounted on the plates as shown in figure 2 to fix the mounting bar to the underside of the trailer and may comprise clamps having a rounded profile to fit onto an axle on the trailer.

Referring now to figures 4 to 6, a driver 40 of the invention comprises a drum or portion 42 having a first end 44 provided with a circumferential ring gear 8, in this embodiment formed on the inner circumference of a flange 9 at the first end of the drum that is wider than the main body 50 of the drum. The main body 50 ofthe drum is sized to accommodate the wheel hub of the trailer. The second end of the drum comprises a base 52 having a plurality of bolt holes 54 spaced on a circle around the axis of the driver and sized to receive bolts mounted on the wheel hub.

In this embodiment the base does not comprise bolts for the wheel, and so in use the driver is placed over the wheel hub with the wheel hub bolts protruding through the bolt holes and the wheel is bolted to the wheel hub, so trapping the driver in place between the wheel and the wheel hub.

In an alternative embodiment the base 52 further comprises a plurality of bolts spaced on a circle centred on the axis of the driver and spaced so as to pass.through the bolt holes on the wheel. In use in this embodiment the driver may be bolted to the wheel hub and then the wheel is bolted to the driver.

The control means preferably comprises remote control means using RF communication and comprising a remote control handset. In one embodiment the remote control handset may comprise a mobile phone and the control means may comprise an application running on the phone. Preferably the apparatus is powered from a battery on the trailer and comprises a power cable adapted to plug into a power circuit on the trailer. In an alternative embodiment the apparatus may be powered from an external power source and comprises a power cable adapted to reach from the trailer to the external power source.

It will be understood that while the embodiment above comprises one mounting bar and two drive units, the apparatus may comprise a second mounting bar and a further two drive units acting on a further pair of wheels of the trailer.

The components of the apparatus are sized to suit the trailer type. In a preferred embodiment the mounting bar comprises 50 mm square outer box sections and a 46 mm square inner box section. Preferably the outer box sections comprise clamps sized to fit around the axle 9f a trailer. The motors preferably comprise an internal gearbox and are reversible, preferably being adapted to move a trailer of 3 tons using two motors and 5.5 tons using four motors. Preferably the motors are 12V motors adapted to run from a standard 110 Amp deep cycle leisure applications battery, and are preferably water-tight. In a preferred embodiment the control means is adapted to give speed control over the drive units to provide speed of movement of a wheel between 17 cm and 30 cm per second. Preferably the control means is usable with both two wheel and four wheel drive apparatus.

Claims

Claims 1. A drive apparatus for a trailer with at least one wheel having an accessible axle wheel hub, in which the apparatus comprises: a driver arranged in use to be mounted on said wheel hub, in which said driver comprises a portion dimensioned to be secured to the wheel hub, a circumferential ring gear provided on a first end of the portion of the driver and a base at a second end of the portion of the driver, the base comprising a means to secure to the wheel hub; and a drive unit arranged in use to be mounted on the trailer comprising an electric motor and shaft driven by the motor having a drive gear at an end of the shaft, the drive gear being moveable relative to the trailer in a direction substantially parallel to the axis of the wheel hub in order to engage with the ring gear to transmit force from the drive unit to the hub drive.

2. A drive apparatus according to claim I wherein the means to secure the driver to the wheel hub comprises a plurality of bolt holes evenly spaced around a circle concentric with the centre of the driver and arranged in use to receive bolts mounted on the wheel hub.

3. Apparatus as claimed in claim 1 or claim 2 wherein the ring gear is provided on the inner circumference of the driver.

4. Apparatus as claimed in claim 3 wherein when the driver is fitted to the wheel hub the ring gear lies within the plane of the outer extent of the tyre mounted on the wheel.

5. Apparatus as claimed in any claim above wherein the shaft is arranged in use to be movable by the motor in order to engage the ring gear.

6. Apparatus as claimed in claim S wherein the motor comprises gear means adapted to move the shaft forward parallel to the axis of the shaft when the motor is energised, and to rotate the shaft about its axis to provide drive force via the shaft gear.

7. Apparatus as claimed in any of claims 1 to 4 wherein the drive unit comprises actuation means to move the drive unit relative to the trailer in order for the shaft gear to engage the ring gear.

8. Apparatus as claimed in claim 7 wherein the drive unit comprises motor means adapted to move the drive unit relative to the wheel hub in a direction substantially parallel to the axis of the wheel hub.

9. Apparatus as claimed in any claim above wherein the drive apparatus further comprises a drive unit mounting bar adapted to be mounted on the trailer and having the first drive unit mounted at a first end of the mounting bar and the second drive unit mounted at the second end of the bar.

10. Apparatus as claimed in claim 9 wherein the mounting bar comprises means to set the spacing apart ofthe drive units.

11. Apparatus as claimed in any claim above wherein the apparatus comprises a first drive unit for a wheel at a first side of the trailer and a second drive unit for a wheel at the opposite side of the trailer and a control means to actuate each drive unit separately.

12. Apparatus as claimed in any claim above wherein the driver further comprises a plurality of bolts adapted to pass through bolt holes in the wheel evenly spaced on a circle concentric with the centre of the driver.

13A driver adapted to be mounted on the wheel hub of the trailer and to be driven by a motor-driven gear, comprising a drum portion dimensioned to fit over the wheel hub, a circumferential ring gear provided on a first end of the drum portion and a base at the second end of the drum portion, the base comprising a plurality of bolt holes evenly spaced around a circle concentric with the centre of the driver and adapted to receive bolts mounted on the wheel hub.

14. Apparatus according to any of the preceding claims wherein the drive unit includes remote control.

15.A trailer comprising a first and a second drivermounted on a wheel hub on each side of the trailer and a first and a second drive unit as described above mounted on the trailer.

16. A method of moving a trailer comprising the steps of: fitting a driver of the apparatus as claimed in any one of claims 1 to 14 to a wheel hub on the trailer and fitting the wheel over the driver; and providing a drive unit of the apparatus as claimed in any one of claims 1 to 14 mounted on the trailer and causing the shaft gear to engage the ring gear and powering the drive unit motor to drive the ring gear.

17. A method as claimed in claim 15 comprising the further step of fixing to the trailer a drive unit mounting bar having a drive unit provided at each end of the bar.