GB2305408A

GB2305408A - A caravan having an electric motor for manoeuvering

Info

Publication number: GB2305408A
Application number: GB9619539A
Authority: GB
Inventors: Alan Muscroft
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-09-19
Filing date: 1996-09-19
Publication date: 1997-04-09
Also published as: GB9519127D0; GB9619539D0

Abstract

A manoeuvring unit for a caravan (5) comprises a bi-directional electric motor connectable to the battery system of the caravan (5) and arranged to drive a road wheel (6). The electric motor may drive the wheel through reduction gearing with an output pinion (17) engaging gear teeth (9) provided on the brake drum (8). The pinion is disengaged from the gear teeth (9) when drive is not required. Belt-and-pulley gearing may be used instead. A wheel at each side may be driven.

Description

CARAVANS This invention relates to a powered manoeuvring unit for caravans, and to caravans provided with such a unit. As the unit is equally usable with products similar to caravans e.g.

boat trailers, the term caravan should be understood to embrace trailers generally.

In recent times, an alternative to the traditional manhandling of a caravan to or from the hitch of a towing vehicle, in to position on a site , a driveway etc., is the availability of a powered unit intended to be temporarily attached to the caravan chassis e.g. as a temporary replacement for the jockey-wheel. Basically, the user replaces the jockey-wheel with such a unit for manoeuvring purposes e.g. to manoeuvre a caravan to and from a parking or storage position e.g. on a driveway, and after completion of manoeuvring operations the unit is removed and the jockey- wheel is replaced. The unit incorporates a ground engaging drive wheel and power to the unit is taken from the conventionally provided 12 volt battery system of the caravan.Whilst such a unit indeed removes the need for manual effort, the use of a single drive wheel located in the vicinity of the towing socket and hence subjected to light loading limits the effectiveness of the unit on poor surfaces such as wet grass or gravel.

A basic object of the invention is to provide an improved unit and a caravan provided with such a unit.

According to a first aspect of the present invention there is provided a manoeuvring unit for a caravan comprising a bi-directional electric motor connectable to the conventionally provided 12 volt battery system of the caravan; speed reduction means connected to the electric motor; a transmission to a road wheel of the caravan; and control means for the unit.

According to a second aspect of the invention there is provided a caravan incorporating a manoeuvring unit as defined above.

According to a third aspect there is provided a caravan comprising a unit in accordance with the first aspect permanently attached to the caravan chassis, and selectively engageable and disengageable with a road wheel of the caravan.

Thus, the invention departs from known powered units in that, save for maintenance and/or repair, the unit is permanently attached, and drive is applied to at least one road wheel of the caravan, which not only avoids the need for the user to inter-exchange repeatedly the jockey-wheel and the powered unit, but applies the drive to a wheel carrying a substantial portion of the weight of the caravan for improved traction, while the jockey wheel is, in the conventional manner, lowered to a ground engaging position for stability and/or steering during operation of the unit and manoeuvring of the caravan.

Although it is possible to power but one road wheel of a single or double axle caravan, a road wheel at each side of the caravan may be powered.

In accordance with another preferred feature, the unit is displaceable, preferably manually, between an active and engaged manoeuvring position, and an inactive, disengaged storage or towing position. Displacement may be arcuate, or linear.

Although the transmission could employ a drive wheel e.g. of synthetic rubber or plastics, for frictional engagement with a road wheel of the caravan, preferably a positive drive is used employing gearing and/or a drive belt, the latter preferably being toothed.

In a preferred arrangement, the conventionally provided brake drum of the road wheel of the caravan is provided with a ring gear engageable by a drive pinion of the unit. In detail, the drive pinion may be located at one end of a support arm pivotally attached to the chassis of the caravan e.g. about an upright axis, the support arm also carrying the drive motor and reduction gearing. A simple and preferred means of effecting manual displacement between active and non-active positions of the support arm is by attaching to the caravan chassis a screw and nut arrangement which is manually operable by the standard crank handle that is provided for conventionally deploying and retracting the legs or steadies that are provided at the four corners of a caravan.As it is inevitable that on some occasions the teeth of the drive pinion and of the ring gear will not immediately inter-engage but will foul one another, a spring arrangement is preferably provided whereby an engaging bias is provided and inter-engagement is instantaneously effected upon start of rotation of the motor, transmission etc.

In detail, the electric motor may have a generally horizontal axis, with an output pinion in mesh with a speed reduction gear wheel on the same shaft as a belt drive gear wheel located at an inboard end of the support arm adjacent its pivot, with the toothed belt extending along the arm to a second belt drive gear wheel located at the outboard end of the arm remote from the pivot, and on the same shaft as the drive pinion. The support arm may also carry a positionally adjustable belt-tensioner roller.

As a means of modifying existing caravans, the conventional brake drum may have a ring gear attached e.g. by welding, or alternatively a ring gear may be cast integrally with a brake drum to provide a replacement drum.

The control means may simply comprise a control panel mounted at a suitable location e.g. in the vicinity of the jockey-wheel, with manually operable switches for forward and reverse running of the motor etc. As the control panel is external to the caravan, the switches need to be not only weatherproof but secure from unauthorised use e.g. by the panel having a lockable closure cover.

The various aspects of the invention will now be described in greater detail, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic plan view of a portion of a caravan fitted with a first embodiment of unit in accordance with the first aspect; and Figures 2, 3 and 4 are respectively side elevation, end elevation, and plan views of a second embodiment of unit in accordance with the first aspect.

Where applicable, like reference numerals are used for like components in all figures.

In the drawings, a caravan manoeuvring unit 1 in accordance with the first aspect comprises an elongate support arm 2, which is adapted to be secured, by an appropriate number of bolts on axes 3, to a longitudinally extending chassis member 4, of the caravan 5, adjacent a road wheel 6. The wheel 6 has a tyre 7 and a brake drum 8. The latter is provided with a ring gear 9.

The support arm 2 also carries a bi-directional electric motor 10 (figures 2 - 4), with an output of the motor in mesh with a speed reduction worm wheel and drive gear box 11. An output shaft 12 of the gear box 11 carries a drive pinion 13, while an endless, toothed belt 14 wraps around a second drive pinion 15 spaced from the first and having a drive shaft 16 carrying a pinion gear 17 adapted to be brought, under the control of the user, into, or out of, engagement with the ring gear 9 of the brake drum 8 for driving, or non-driving, of the road wheel 6, as required.

The belt 14 also has a jockey pulley 18. Between the chassis member 4 and the arm 2 a screw arrangement 19 is provided, terminating in an exposed nut 20 engageable by the conventionally provided cranked jack handle of the caravan. In the embodiment of figure 1, this is effective to swing the arm 2 through but a few degrees, as indicated by arrow A in figure 1, between its inner, storage position, and outer, active position. In the embodiment of figures 2 - 4, linear displacement is effected with a beam 21 which is displaceable with respect to the arm 2 by being carried on a pair spaced-apart slide pins 22 having springs 23 and 24, whilst a further compression spring 25 is located between the beam 21 and the pinion 15.

Not shown are electrical leads, and user operable control switches between the motor 10 and the conventionally provided 12volt battery of the caravan 5.

Claims

1. A manoeuvring unit for a caravan comprising a bidirectional electric motor connectable to the conventionally provided 12 volt battery system of the caravan; speed reduction means connected to the electric motor; a transmission to a road wheel of the caravan; and control means for the unit.

2. A unit as claimed in Claim 1 wherein the transmission employs a drive wheel eg. of synthetic rubber or plastics, for frictional engagement with a road wheel of the caravan.

3. A unit as claimed in Claim 1, wherein the transmission employs gearing and/or drive belt, the latter preferably being toothed to provide a positive drive.

4. A unit as claimed in Claim 3, incorporating a drive pinion.

5. A unit as claimed in Claim 4, wherein the drive pinion is located at one end of a support arm displaceable, preferably manually, between an active and engaged manoeuvring position, and an inactive, disengaged, storage or towing position.

6. A unit as claimed in claim 5, wherein the support arm is arcuately displaceable by one end there of being pivotally attached to the chassis of a caravan eg about an upright axis.

7. A unit as claimed in claim 5 wherein the support arm is linearlly displaceable.

8. A unit as claimed in any one of Claims 5-7, wherein the support arm also carries the drive motor and reduction gearing.

9. A unit as claimed in any preceding Claim, wherein a spring arrangement is provided whereby an engaging bias is provided on the drive pinion and inter-engagement is instantaneously effected upon start of rotation of the motor, transmission etc.

10. A unit as Claim in any preceding Claim, wherein the electric motor has an output pinion in mesh with a speed reduction gear wheel on the same shaft as a belt drive gear wheel located at an inboard end of the support arm adjacent tis pivot, with the toothed belt extending along the arm to a second belt drive gear wheel located at the outboard end of the arm remote from the pivot, and on the same shaft as the drive pinion.

11. A caravan manoeuvring unit substantially as herein before described with reference to figure 1 of the accompanying drawings.

12. A caravan manoeuvring unit substantially as herein before described with reference to figures 2-4 of the accompanying drawings.

13. A caravan incorporating a manoeuvring unit as defined in any preceding Claim.

14. A caravan comprising a unit in accordance with any one of Claims 1 to 12, permanently attached to the caravan chassis, and selectively engageable and disengageable with a road wheel of the caravan.

15. A caravan as Claim in Claim 13 and 14 wherein one road wheel at one side of the caravan is drive-able by an unit in accordance with any one of Claims 1 to 12.

16. A caravan as Claim in Claim 13 and 14 wherein one road wheel at each side of the caravan is drive-able by an unit in accordance with any one of Claims 1 to 12.

17. A caravan as Claim in any one of Claims 13 to 16, wherein the or each unit is displaceable, preferably manually, between an active manoeuvring position, and an inactive storage position.

18. A caravan as Claim in any one of Claims 13 to 117, wherein the conventionally provided brake drum of the or each road wheel of the caravan is provided with a toothed drive ring engageable by a drive pinion of the unit.

19. A caravan as Claim in any one of Claims 13 to 18, provided with a screw and nut arrangement which is manually operable by the standard crank handle that is provided for conventionally deploying and retracting the legs or steadiness that are provided at the four corners of a caravan, for effecting manual displacement between active and non-active positions of the support arm.

20. A caravan as Claim in any one of Claims 13 to 19, wherein the or each conventional brake shoe has a tooth ring attached eg. by welding, or alternatively a tooth ring may be cast integrally with a brake drum to provide a replacement drum.

21. A caravan substantially as herein before described with reference to the accompanying drawings.