GB2125748A - Electric vehicle systems - Google Patents

Abstract

An electric vehicle (particularly a model vehicle) system comprises a surface including discrete areas e.g. strips 2, 3, of conductive material with sources of different electric type, e.g. positive and negative d.c., applied thereto, and an electric vehicle which has, e.g. four, pickups 6'-9' connected via isolators, e.g. diode rectifiers, to positive and negative lines in the vehicle so that the pick-ups are not source type sensitive. Control signals for steering, speed, forward/reverse, brakes and lights may also be communicated to a receiver/decoder within the vehicle via the pick-ups and the conductive areas. The conductive areas may be strips as shown or patches arranged in rows and columns, and may be inlaid in a base of isolating material to form track or board sections. <IMAGE>

Description

SPECIFICATION Improvements in or relating to electric vehicle systems This invention relates to electric vehicle systems and in particular though not exclusively, to model electric vehicle systems used for amusement or training purposes.

In recent years two main types of model electric vehicle system have evolved.

One such system involves the use of a radio control link between a battery powered hand held controller and a battery driven model vehicle, for example a model car. The car commonly features steering, forward and reverse control and speed control achieved by means of actuators relays, rheostats and the like controlled by a decoder/receiver in dependence upon signals transmitted to the car, which usually requires to be equipped with a receiving aerial, from the controller. Such a system has the merit that within range of the transmitter in the hand held controller, the car is capable of a wide range of manoeuvres corresponding, in elaborate systems, to those of a real motor car.

However a radio control model car system as above described has a number of disadvantages many of which stem from the fact that batteries are required to power not only the electric drive motor but also the controls of the car and of course the hand controller/ transmitter itself-although conceivably a mains transformer could be used for this last mentioned item even if this is not commonly done. Not only is the running cost associated with the use of batteries expensive if batteries of the rechargeable type are not used, but to achieve a satisfactory performance the battery capacity has to be considerable adding not only to the weight (which of course militates against performance) but also to the bulk and overall size of the model car. It is also often found that the running time between battery replacement (or recharging) is undesirably short.In general such model car systems are regarded as unsuitable for table top operation, particularly if more than one model car is to be in operation at the same time.

The other main type of system referred to above involves the use of a slotted track and is usually employed to simulate car racing.

The operation of such a system is commonly referred to as "slot car racing". As is well known the slot within the track dictates the direction in which the model car is to travel and, in more elaborate examples, controls the steering of the front wheels to simulate reality.

Power to drive the model car motor is derived from strip contacts on either side of the slot with brush contractors extending down from the underside of the car. In fact the guiding mechanism engaging the slot usually carries the brush contactors also. The only control exercisable by an operator is commonly the speed of the car, by controlling the current passed to the strip contacts on the track, although it is possible to provide for a braking effect to be achieved.

The advantage of a slot car system is that it does not rely upon the use of batteries carried on the car which may thus be relatively light and relatively small to give a good performance whilst suitable for a table top system.

However whilst changeovers and crossovers may be incorporated in a slot car system, a serious disadvantage resides in the fact that the operator has no real control of the direction of travel of the model car beyond that of a predetermined nature which may be achieved by the use of a changeover. For example on any given stretch of straight track one model car following another along the same slot may not be pulled over to pass.

Furthermore, not only does the slot and guiding mechanism provide "unnatural" handling characteristics but also if the model car is caused to skid or slide to such an extent that the guiding mechanism become disengaged from its slot, resulting also in loss of motive power, the car becomes stationary and immobile even if a real car in a corresponding situation would be capable of continuing.

The present invention seeks to provide an improved electric vehicle system and in particular an improved model electric system in which one or more of the above disadvantages are mitigated.

According to this invention, an electric powered vehicle system comprises a surface over which an electric powered vehicle is to travel, which surface comprises discrete areas of electrically conductive material some of which are connected to a source of one electrical type and some of which are connected to a source of another electrical type, said vehicle including a plurality of electrical pickups extending towards said surface whereby to contact said areas in dependence upon the position of said vehicle on said surface and two electrical supply rails from which the electric motor of said vehicle is supplied with power, at least one of said pick-ups being connected to one of said two electrical supply rails requiring connection to said source of one electrical type and at least one other of said pick-ups being connected to the other of said two electrical supply rails requiring connection to said source of another electrical type, there being interposed between said pick-ups and the respective supply rails means for isolating each supply rail from a source of electrical type other than that to which that supply rail is required to be connected.

Preferably said system is operative with direct current in which case said one electrical type is of positive polarity and said other electrical type is of negative polarity and said isolating means may be simple unilaterally conductive devices, for example diode rectifiers.

Whilst not preferred, said system may be operative with alternating current in which case, in a single phase system, said one electrical type may be neutral and the other live.

In many cases however the complexity introduced by alternating current operation will not be justifiable and if a primary source of power is of alternating current (e.g. the mains supply), rectification is desirable as a first step.

With direct current operation, one of the polarities may be at earth potential.

The cross-sectional dimensions of the effective contacting surface of each pick-up must be sufficiently smaller than the smallest distance separating one discrete area of electrically conductive material from another as to avoid bridging between the two thereby causing short circuits.

Preferably each of said plurality of pick-ups is connected to each of said supply rails via means for isolating that supply rail from a source of electrical type other than that to which that supply rail is required to be connected.

Preferably said discrete areas are provided as an array of elongate conductive strips extending at least approximately in the same direction with one conductive strip being connected to said source of one electrical type (e.g. positive polarity d.c.) and conductive strips on either side thereof being connected to said source of said other electrical type (e.g. negative polarity d.c.) Preferably alternate conductive strips are connected to said source of one electrical type and the remaining conductive strips are connected to said source of said other electrical type.

Preferably said conductive strips are inlaid in a base of electrically insulating material so as to provide a substantially smooth surface over which said vehicle may travel.

Said conductive strips may extend substantially straight and parallel over an expansive area over which said vehicle may operate, or said strips may follow a track to which operation of said vehicle is confined. Particularly where said system is a model electric vehicle system, said expansive area or said track may be made up of portions provided to fit one to another.

Said conductive strips may in places be curved in the plane of the surface but preferably the separation from strip to strip in such case is maintained throughout such curving.

Preferably said conductive strips are of substantially constant width through their lengths and each strip is preferably of width similar to each other strip.

Whilst said vehicle may be provided with any plurality, including two, pick-ups, preferably said vehicle has four pick-ups, two of which are towards the front of the vehicle and two of which are towards the rear.

Preferably the two pick-ups towards the front of the vehicle on the one hand and the two pick-ups towards the rear on the other hand are disposed transversely on either side of the longitudinal axis of the vehicle.

Preferably again said two pickups towards the front of the vehicle are spaced apart to an extent different, and preferably to a lesser extent, from that to which said two pick-ups towards the rear of the vehicle are spaced apart.

Preferably either the two pick-ups towards the front of the vehicle or the two pick-ups towards the rear of the vehicle are spaced apart such that the vehicle standing with its longitudinal axis aligned with and between two conductive strips one of said two pick-ups makes contact with one of said two conductive strips adjacent that edge thereof which is nearer the other conductive strip whilst the other of said two pick-ups makes contact with the other of said two conductive strips adjacent the edge therof which is nearer said one conductive strip, whilst at the same time one of the other two pick-ups makes contact with said one conductive strip adjacent that edge thereof further from said other conductive strip and the other of said other two pick-ups makes contact with said other conductive strip adjacent the edge thereof further from said one conductive strip.

Whilst not preferred, said discrete areas of conductive material may be in the form of patches, for example square, rectangular, diamond shaped or circular, In this last mentioned case, preferably said discrete areas are of similar shape and size arranged in a matrix of rows and columns across said surface, alternate discrete areas in each row and each column being connected to a source of said one electrical type and the remaining discrete areas in each row and column being connected to a source of said other electrical type.

Preferably each discrete area is rectangular and preferably square.

Preferably each alternate discrete area in a row is staggered relative to the other discrete areas on either side thereof in the same row whereby to overlap the space between adjacent discrete areas in the column on either side of said row.

Preferably, and particularly where said system is a model electric vehicle system, means are provided for transmitting control signals to said vehicle via said conductive areas and said pick-ups.

Preferably, at said vehicle, each pick-up is connected via suitable power supply isolating means (d.c. blocking capacitors in the case of d.c. operation) to a vehicle borne receiver/decoder unit provided to receive control signals intended for said vehicle, means being provided for utilising said decoded control signals to effect at least steering control.

Preferably means are provided for utilising said decoded control signals to effect control of other functions such as forward and reverse control, speed control, braking control and control of lights carried by said vehicle.

By providing different channels of communications for each, a plurality of vehicles may be operated at one time.

The invention is illustrated in and further described with reference to the accompanying drawings in which: Figure 1 shows in plan view a portion of track, part broken away to the left as viewed, utilised in one example of model electric car system in accordance with the present invention, Figure 2 is an end elevation of the portion of track shown in Fig. 1, viewed from the right.

Figure 3 is a view of the underside of a model racing car intended for use with the track shown in Figs. 1 and 2 and representing schematically the pick-ups by which contact is made with conductive areas of the track.

Figure 4 shows a plan view of an intermediate portion of track and illustrates the means by which d.c. power and control signals are applied to the conductive strips of the track.

Figure 5 is a circuit diagram of the electrical system for drive and control of a typical model car for use in a model car system in accordance with the present invention.

Figures 6 and 7 each illustrate a different form of pick-up which may be utilised in a system in accordance with the present invention, and Figure 8 illustrates another example of model electric car system in accordance with the present invention in which no track as such is used but an expansive area over which a model vehicle may operate.

In all Figures, like references are used to denote like parts.

Referring to Figs. 1 and 2 in this example of electric model vehicle system in accordance with the present invention the surface over which the vehicle is to run is in the form of a track. Fig. 1 shows a plan view and Fig. 2 an end elevation viewed from the right of part of one portion of track incorporating a curve. A number of portions may be united end to end to form a circuit in a manner analogous to that in the case of a slot car layout. Each portion is provided to plug into the next.

The portion of track comprises an elongate sheet of insulating material such as fibre board or an extruded plastics material, 1, into which are inlaid strips referenced 2 or 3, of conductive material such as copper or other suitable material as used for the strip contacts of a slot car system. The strips 2, 3 are arranged such that their upper surfaces are flush with the upper surface of insulating sheet 1 to present a substantially smooth running surface for a model vehicle travelling along the track. The conductive strips 2, 3 are fixed into the sheet 1 by a suitable adhesive such as epoxy resin. In this example the surface conductive strips are approximately twice the width of the surface strips of insulating material which separate them, the former being approximately eight millimetres in width.

Electrical contact from one portion of the track to the next is provided for by edge connectors of which those shown to the right, as viewed, in Fig. 1 are male and formed by the ends 4, 5 of the strips 2, 3 suitably shaped and bent.

By means to be described later, in operation negative d.c. electrical potential is applied to the strips referenced 2 and positive d.c. electrical potential is applied to the strips referenced 3. Also applied to the strips 2 and 3 are control signals to be transmitted to a vehicle upon the track surface.

Referring to Fig. 3, this represents the underside of a model racing car intended to travel upon the track shown in Figs. 1 and 2 in order to illustrate the disposition of pick-ups intended to make electrical contact with the strips 2, 3 of Figs. 1 and 2. No attempt has been made to illustrate details of transmission, steering detail or the like since this is as well known per se.

In this particular case four pick-ups are used, referenced 6, 7, 8 and 9. The positions each typically occupy when the car is upon the track shown in Figs. 1 and 2 are represented at 6', 7', 8' and 9' respectively in those last mentioned two Figures.

The area of contact of each of the pick-ups 6, 7, 8 and 9 is chosen to be as large as possible consistent with avoiding the possibility of any of the pick-ups bridging the surface strips of insulating material between conductive strips 2, 3 and thereby causing a short circuit as, due to the motion of the car, a pickup moves from one conductive strip 2 or 3 to an adjacent conductive strip 3 or 2.

It should be noted at this point that the pick-ups 6, 7 8 and 9 are not dedicated to either electrical polarity. The disposition of the pick-ups 6, 7, 8 and 9 is chosen with the objective that whatever the position or attitude of the car upon the track, at least one, any one, of the pick-ups 6, 7, 8 or 9 is in contact with a conductive strip 2 to which negative potential is applied whilst at least one other, any one other, of the pick-ups 6, 7, 8 or 9 is in contact with a conductive strip 3 to which positive potential is applied.To this end, the disposition chosen in this particular example is such that rearward pick-up 7 is adjacent one edge of a conducting strip whilst forward pick up 8 is adjacent the other edge of the same strip and the rearward pick-up 6 is adjacent the further edge of the next adjacent conduct ing strip whilst forward pick-up 9 is adjacent the other edge of the last mentioned strip.

With this disposition, the car may move in operation from one side of the track to the other, in either direction along the track and even directly across the track whilst the above stated objective tends to be maintained.

In fact, in many cases failure to maintain the stated objective continuously, whilst unde sirable, may not prevent operation since, once moving, the momentum of the car may carry it past positions in which the stated objective is lost. Thus a system may be provided in which only two or three contacts are provided, but this is not generally regarded as satisfac tory.

Before describing the electrical system mounted within the~model~~car, reference will be made to Fig. 4 which illustrates the method used in order to apply power and control signals to the conductive strips 2, 3.

An intermediate short straight length of track is provided as illustrated intended to fit be tween other lengths of track as illustrated in Figs. 1 and 2. As before, male end connectors 4, 5 are formed at one end whilst, repre sented in dotted outline, at the other end are female end connectors 4', 5' into which the male end connectors of the next adjacent length of track to the left as viewed would be plugged.

On the underside of the track, and inlaid for protection, are two conductive strips repre sented by the dashed lines 10, 11. Strip 10 is connected by rivetting or other suitable means at points 1 2 to surface strips 4. Strip 11 is similarly connected at points 1 3 to surface strips 5. A mains transformer/isolator 14 incorporating a rectifer applies d.c. current of positive polarity to strip 11 and of negative polarity to strip 1 2. The voltage output of transformer 14 will depend upon that required to operate the equipment carried by the car, but will typically be nine to twelve volts.

Connected to apply coded control signals via d.c. blocking capacitors 1 5 to strips 10 and 11 and thus to surface conductive strips 2, 3 is a controller/transmitter 1 6 which, allowing for the fact that transmission through space is not required, may be constructed along the lines of a controller/transmitter for a radio controlled model.Whilst not shown, the controller/transmitter has a panel present ing to an operator a first lever moving from left to right and connected to generate corre sponding steering control signals; a second lever moving forward and backwards to gener ate speed control and stop control signals (the arrangement being that movement further for ward increases speed whilst pulling the lever backwards beyond certa+n - pontgerierates a- - --stop-control~signal), a frward/reverse switch and an auxiliary switch which, when operated, generates an auxiliary control signal which may be used at the car to operate lights.

For each car to be used upon the track a separate controller/transmitter is provided, each car with its associated controller/ transmitter being allocated an individual com munication channel.

The electrical system of the model car will now be described with reference to Fig. 5.

Terminals 17, 18, 1 9 and 20 are connected respectively to pick-ups 7, 8, 9 and 10 shown in the underside view of the model car in Fig.

3.

Terminals 17, 18, 19 and 20 are con nected via rectifiers 21, 22, 23. and 24 respectively to a positive supply rail 25. Recti fiers 21, 22, 23, and 24 are polarised so as to pass current into the positive supply rail 25 whenever the associated pick-ups 7, 8, 9 and 10 respectively are in contact with any of the track surface conductive strips 2 of positive polarity.

Terminals 17, 18, 1 9 and 20 are also connected via rectifiers 26, 27, 28 and 29 to a negative supply rail 30. Rectifiers 26, 27, 28 and 29 are polarised so as to be conduc tive whenever the associated pick-ups 7, 8, 9 and 10 respectively are in contact with any of the track surface conductive strips 1 of negative polarity.

Thus, as mentioned previously, provided any one of the pick-ups 7, 8, 9 or 10 is in contact with a negative track surface conduc tive strip 1 and any one of the others is in contact with a positive track surface conductive strip 2, negative and positive supply rails 30 and 25 will be "live" Also connected to terminals 17, 18, 1 9 and 20, via d.c. blocking capacitors 31, 32. 33 and 34 respectively, is the input lead 35 of a receiver/decoder unit 36, which selects con trol signal transmissions from the controller/ transmitter 1 6 of Fig. 2 intended for this particular model car and decodes these.

The d.c. electric motor of the car is repre sented at 37. Motor 37 is reversible and connected to positive and negative rails 25 and 30 via two ganged switches 38 and 39.

Each switch 38, 39 has an input pole a and three output poles b, C and d. One input terminal of motor 37 is connected to output pole C of ganged switch 38 and to output pole dof ganged switch 39. The other input terminal of motor 37 is connected to output pole C of ganged switch 39 and to output pole d of switch 38.

Input pole a of switch 39 is connected directly to negative rail 30. Input pole a of switch 38 is connected to positive rail 25 via a current controlling varistor unit 40 con trolled by an output from receiver/decoder 36 so as to effect speed control in dependence --upon speed -controt signals received from con troller/transmitter 1 6 of Fig. 4.

The switch wipers of ganged switches 38, 39 are arranged tn he moved in unison as represented by the solid and dashed line arrows under control of a forward/reverse/stop switch control unit 41 which is itself controlled by an output from receiver/decoder 36. The arrangement is such that the wipers of both switches 38, 39 are normally in, and in fact spring biased towards (although this is not shown), the "forward" position with input poles a connected to respective output poles c. The motor is linked to the rear wheels of the car such that with the direction of turning thus induced the car moves forward at a speed dependent upon the setting of speed control unit 40.

When receiver/decoder 36 detects a verse" control signal, it causes switch control unit 41 to cause the wipers of switches 38 and 39 to move in the direction of the dashed arrows so that now input poles a are connected to respective output poles d and the direction of rotation of the motor, and thus the direction of movement of the car, reverses.

When receiver/decoder 36 detects a "stop" control signal, it causes switch control unit 41 to cause the wipers of switches 38 and 39 to move in the direction of the solid arrows so that now input poles a are connected to respective output poles b and power is removed from the motor 37. It will be noted that whilst pole b of switch 38 is free, pole b of switch 39 is connected to a brake actuating relay 42 which energises a pair of terminal 43. Whilst not shown, connected to terminals 43 is an electro-magnetic brake which in this example simply comprises a disc of magnetic material attached to rotate with the rear axle drive shaft (propeller shaft) adjacent an electro-magnet connected to terminals 43 and which attracts the disc when braking is required.

Whilst not featured in this particular example a pair of miniature pea bulbs may be connected to terminals 43 to act as brake lights to the rear of the car.

Receiver/decoder 36 also controls the movements of a steering actuator 44 in dependence upon steering control signals received from controller/transmitter 1 6 of Fig.

4. Shafts 45 are connected to steerings arms not shown but as known per se.

Also shown controlled by receiver/decoder 36 is an auxiliary relay 47. Since the model at present under consideration is a model racing car this serves no purpose, but in a saloon or sports car model the output terminal 48 thereof may be connected to miniature pea bulbs at the front of the car which simulate headlamps actuated when the appropriate signal is decoded by the receiver/decoder 36 as a result of the light switch being operated at the controller/transmitter 1 6 of Fig. 4.

Provided that the disposition of the pick-ups 7, 8, 9 and 10 is suitably chosen and the track surface conductive strips 2, 3 are not separated by too wide an expanse of surface insulator material, a reservoir battery should not be necessary in the car. However if a reservoir battery of the rechargeable type is fitted between positive and negative rails 25 and 30 this will be recharged during normal operation. The biasing of the switches 38 and 39 to the "forward" position should result in the car continuing to move forward until suitable contact is re-established with surface conductive strips 2, 3 provided that the speed control unit 40 is arranged such that it always passes some current sufficient to induce some movement of the car.

Naturally, if desired, speed control unit 40 could be arranged oppositely to give maximum speed when no control is applied, but this is not preferred.

Referring now to Figs. 6 and 7, these represent two different types of pick-up which may be used for the pick-ups 7, 8, 9 and 10 shown in Fig. 3. The type illustrated in Fig. 6 is a simple springy contact having a spoon shaped end 49 adapted to contact the track surface. With this type of pick-up, quite similar to the type of pick-up used previously in three rail model electric train systems, the area of contact may be reasonably accurately controlled thus reducing the risk of undesired bridging between two track surface conductive strips between which the pick-up is passing. The same is so with the type of pick-up shown in Fig. 7 although the last mentioned does not possess the merit of simplicity.

Referring to Fig. 7, the pick-up consists of a stainless steel ball bearing 50 seated upon a seating 51 at the base of a tube 52. The ball bearing 50 is urged into the seating 51 and caused to protrude through an aperture therein by a conductive spring 53 acting upon a conductive cup shaped bearing 54 on top of the ball bearing 50. The spring is retained by means of a conductive plug 55 in the top of the tube 52, which plug is also threaded to take a terminal nut.

Referring to Fig. 8, in this case the surface over which the model vehicle is to run is not in the form of a track but an expansive sheet which encompasses the whole of the area over which the vehicle is to operate. In essence the principle is identical to that used in connection with the track save that instead of six conductive strips extending over a relatively short portion of track, a large number of parallel conductive strips, say one hundred, extend for 2 metres to give an operating area, with conducting and insulating strip widths as described with reference to Fig. 1, of approximately 3 x 2 metres. No attempt has been made to shown connections to the negative conductive strips 2 and positive conductive strips 3, but this aspect and the application of control signals is similar to that already described with regard to the track system.Upon this expansive sheet, over which, it will be appreciated, a model car as previously described may drive at substantially any angle, may be placed obstacles, model buildings or the like to simulate any desired type of model layout including, of course, a racing circuit. A model railway may also be laid upon the expansive sheet and both the railway system and the car system operated simultaneously.

The expansive sheet may of course be of sectional form using connectors as already described with reference to the track system represented in Fig. 1.

It may also be possible to form the sheet as a flexible printed circuit which may simply be rolled up when not in use.

In all cases the insulating surface may be coloured to blend with the colour of the conducting surface strips.

As will be appreciated, whilst described particularly in terms of models, the invention also has possible application in the field of real transport as a means of applying at least electrical power, if not control, to a load or passenger carrying vehicle on a roadway or over an area such as the floor space of a factory or warehouse particularly of the automated kind. In such application one might use conductive concrete or other surfacing material which has been rendered conductive for the surface conductive strips and non-conductive concrete or other surfacing material for the surface insulating strips therebetween.

Such use might overcome one of the basic problems of electric vehicles, that of operating range. If a storage battery or array of storage batteries is carried this or these may be subjected to charging whilst the vehicle is operating within an area provided in accordance with the present invention, the power available from the batteries being utilised at other times.

For the avoidance of doubt, it should be noted that whenever the position of a pick-up is referred to herein, it is the region of contact which is material of course.

Claims (31)

1. An electric powered vehicle system comprising a surface over which an electric powered vehicle is to travel, which surface comprises discrete areas of electrically conductive material some of which are connected to a source of one electrical type and some of which are connected to a source of another electrical type, said vehicle including a plurality of electrical pick-ups extending towards said surface whereby to contact said areas in dependence upon the position of said vehicle on said surface and two electrical supply rails from which the electric motor of said vehicle is supplied with power, at least one of said pick-ups being connected to one of said two electrical supply rails requiring connection to said source of one electrical type and at least one other of said pick-ups being connected to the other of said two electrical supply rails requiring connection to said source of another electrical type, there being interposed between said pick-ups and the respective supply rails means for isolating each supply rail from a source of electrical type other than that to which that supply rail is required to be connected.

2. A system as claimed in claim 1 and wherein said system is operative with direct current said one electrical type being of positive polarity and said other electrical type being of negative polarity.

3. A system as claimed in claim 2 and wherein said isolating means comprise diode rectifiers.

4. A system as claimed in claim 2 or 3 and wherein one of said polarities is at earth potential.

5. A system as claimed in any of the above claims and wherein each of said plurality of pick-ups is connected to each of said supply rails via means for isolating that supply rail from a source of electrical type other than that to which that supply rail is required to be connected.

6. A system as claimed in any of the above claims and wherein said discrete areas are provided as an array of elongate conductive strips extending at least approximately in the same direction with one conductive strip being connected to said source of one electrical type and conductive strips on either side thereof being connected to said source of said other electrical type.

7. A system as claimed in claim 6 and wherein alternate conductive strips are connected to said source of one electrical type and the remaining conductive strips are connected to said source of said other electrical type.

8. A system as claimed in claim 6 or 7 and wherein said conductive strips are inlaid in a base of electrically insulating material so as to provide a substantially smooth surface over which said vehicle may travel.

9. A system as claimed in any of claims 6 to 8 and wherein said conductive strips extend substantially straight and parallel over an expansive area over which said vehicle may operate.

1 0. A system as claimed in any of claims 6 to 8 and wherein said conductive strips follow a track to which operation of said vehicle is confined.

A A system as claimed in claim 9 or 10 and wherein said expansive area or track, as the case may be, is made up of portions provided to fit one to another.

12. A system as claimed in any of claims 6 to 8 or claim 10 and wherein said conductive strips are in places curved in the plane of the surface, the separation from strip to strip in such case being maintained throughout such curvina.

1 3. A system as claimed in any of claims 6 to 1 2 and wherein said conductive strips are of substantially constant width through their lengths.

1 4. A system as claimed in claim 1 3 and wherein each strip is of width similar to each other strip.

1 5. A system as claimed in any of the above claims and wherein said vehicle has four pick-ups, two of which are towards the front of the vehicle and two of which are towards the rear.

1 6. A system as claimed in claim 1 5 and wherein the two pick-ups towards the front of the vehicle on the one hand and the two pickups towards the rear on the other hand are disposed transversely on either side of the longitudinal axis of the vehicle.

1 7. A system as claimed in claim 1 5 or 1 6 and wherein said two pick-ups towards the front of the vehicle are spaced apart to an extent different from that to which said two pick-ups towards the rear of the vehicle are spaced apart.

18. A system as claimed in claim 1 5 or 1 6 and wherein said two pick-ups towards the front of the vehicle are spaced apart to an extent lesser than that to which said two pickups towards the rear of the vehicle are spaced apart.

1 9. A system as claimed in claim 1 7 and wherein either the two pick-ups towards the front of the vehicle or the two pick-ups towards the rear of the vehicle are spaced apart such that with the vehicle standing with its longitudinal axis aligned with and between two conductive strips one of said two pick-ups makes contact with one of said two conductive strips adjacent that edge thereof which is nearer the other conductive strip whilst the other of said two pick-ups makes contact with the other of said two conductive strips adjacent that edge thereof which is nearer said one conductive strip, whilst at the same time one of the other two pick-ups makes contact with said one conductive strip adjacent that edge thereof further from said other conductive strip and the other of said other two pickups makes contact with said other conductive strip adjacent the edge thereof further from said one conductive strip.

20. A system as claimed in any of claims 1 to 5 and wherein said discrete areas of conductive material are in the form of patches.

21. A system as claimed in claim 20 and wherein said discrete areas are of similar shape and size arranged in a matrix of rows and columns across said surface, alternate discrete areas in each row and each column being connected to a source of said one electrical type and the remaining discrete areas in each row and column being connected to a source of said other electrical type.

22. A system as claimed in claim 21 and wherein each discrete area is rectangular.

23. A system as claimed in claim 22 and wherein each discrete area is square.

24. A system as claimed in any of claims 21 to 23 and wherein each alternate discrete area in a row is staggered relative to the other discrete areas on either side thereof in the same row whereby to overlap the space between adjacent discrete areas in the column on either side of said row.

25. A system as claimed in any of the above claims and wherein means are provided for transmitting control signals to said vehicle via said conductive areas and said pick-ups.

26. A system as claimed in claim 25 and wherein at said vehicle, each pick-up is connected via suitable power supply isolating means (d.c. blocking capacitors in the case of d.c. operation) to a vehicle borne receiver/decoder unit provided to receive decode control signals intended for said vehicle, means being provided for utilising said decoded control signals to effect at least steering control.

27. A system as claimed in claim 26 and wherein means are provided for utilising said decoded control signals to effect control of other functions such as forward and reverse control, speed control, braking control and control of lights carried by said vehicle.

28. A system as claimed in any of claims 25 to 27 and wherein different channels of communications of control signals are provided for each of a number of vehicles to be operated with the system at one time.

29. An electric powered vehicle system substantially as herein described with reference to accompanying Figs. 1 to 4.

30. An electric powered vehicle system or a model car substantially as herein described with reference to Fig. 5 of the accompanying drawings.

31. An electric powered vehicle system substantially as herein described with reference to Fig. 8 of the accompanying drawings.