WHEEL DISPLAY SYSTEM

SYSTEME D'AFFICHAGE SUR ROUE

English Abstract

A taxi has four radially extending arrays of LEDs (38A
to 38D) mounted one on each hub cap. A local receiver
(32A to 32D) in each hub cap receives data representing a
desired image from a local transmitter (24) and stores it in
a local memory (34A to 34D). A local control unit (36A to
36D) in each hub cap selectively energises the LEDs in the
associated array (38A to 38D) in the required sequence (as the
hub cap rotates) to produce an apparent image corresponding
to the desired image. A central control station (2) supplies data
representing the desired image to a receiver (14) in the taxi.
This data is only stored in an associated store (20) when a gate
(18) responds to a code in the transmitted data corresponding
to that particular taxi. The stored data is then downloaded from
the memory by the local transmitter (24).

French Abstract

Dans cette invention, un taxi comporte quatre barrettes de DEL s'étendant radialement (38A à 38D), montées chacune sur chacun des enjoliveurs. Un récepteur local (32A à 32D) placé dans chaque enjoliveur reçoit des données représentant une image choisie provenant d'un émetteur local (24), et les mémorise dans une mémoire locale (34A à 34D). Une commande locale (36A à 36D) placée dans chaque enjoliveur active sélectivement la DEL de la barrette associée (38A à 38D) dans la séquence appropriée (lorsque l'enjoliveur tourne), afin de produire une image apparente correspondant à l'image choisie. Une station de commande centrale (2) fournit à un récepteur (14) situé dans le taxi les données représentant l'image choisie. Ces données sont uniquement mémorisées dans une mémoire associée (20) lorsqu'une passerelle (18) répond à un code, contenu dans les données transmises, correspondant au taxi en question. Les données mémorisées sont ensuite téléchargées de la mémoire à l'aide de l'émetteur local (24).

Claims

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CLAIMS
1. A wheel display system for producing an image display on one or more
rotating
wheels comprising:
transmission means at a central location and receiver means at a location
associated with said wheels, said transmission means being arranged to
transmit data
representative of a desired image to the receiver means;
local transmission means for transmitting data representative of said desired
image
to a local receiver arranged to be mounted on the one or more rotating wheels;
a radially extending array of light emitting devices arranged to be mounted on
the
one or more rotating wheels;
control means for the one or more rotating wheels responsive to the data
received
by the local receiver to energise the light emitting devices in a sequence
which, as the
wheel rotates, results in an apparent image corresponding to said desired
image; and
a memory for storing data received by said receiver means and a gate for
inhibiting storage of data in said memory from said receiver means until
opened in
response to a code received by said receiver means.
2. A system according to Claim 1, wherein each local receiver and associated
local
control means and array of light emitting devices are mounted on a wheel hub
cap.
3. A system according to Claim 2, wherein the light emitting devices are
mounted in
the inside of the hub cap to face a radially extending slot in the hub cap
through which the
array can be viewed.
4. A system according to Claim 2 or to Claim 3, wherein the local receiver,
associated local control means and array of light emitting devices are powered
by
rechargeable battery means mounted on the hub cap.
5. A system according to Claim 4, including generating means mounted on the
hub
cap for keeping the rechargeable battery charged.

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6. A system according to Claim 5, wherein the generating means comprises light
cell
means.
7. A system according to Claim 5, wherein the generating means comprises a
stator
rigid with said hub cap and extending coaxially therewith and a rotor carrying
an inertial
load to produce relative rotation between the stator and rotor as the hub cap
accelerates
and decelerates.
8. A system according to any one of Claims 3 to 7, including trigger means
mounted
on the hub cap to be triggered each time the trigger means passes a particular
angular
position, the trigger means acting to cause the image initiated by the local
control means
to be initiated in the same angular position on each rotation of the hub cap.
9. A system according to Claim 8, wherein the trigger means comprises a reed
relay
which is triggered by a magnet located adjacent said particular angular
position.
10. A system according to any one of Claims 1 to 9, wherein said local
transmission
means communicates with said local receivers by radio frequency transmissions.
11. A system according to any one of Claims 1 to 10, including storage means
associated with each local receiver for storing the data recorded by said
local receiver.
12. A system according to any one of Claims 1 to 11, wherein the receiver
means is
mounted in a taxi and there are four local receivers associated with the
receiver means
one for each wheel of the taxi whereby all four wheels of the taxi can display
a desired
image as the wheels rotate.

Description

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WHEEL DISPLAY SYSTEM
The present invention relates to a wheel display system for creating a visual
display
on one or more rotating wheels.
PCT Publication No WO 98/59333 discloses a bicycle wheel carrying an elongate
array of light emitting diodes (LEDs) which are selectively energised as the
wheel rotates to
generate an apparently stationary image due to the phenomena known as
persistence on the
retina. The energisation of the array is carried out by a control unit mounted
on the wheel
in accordance with a program stored in the memory within the control unit. The
stored
program determines the sequence in which the different LEDs of the array are
to be
energised. By selecting the timing and energisation of the different LEDs in
accordance
with the predetermined program, the observer will see an apparently stationary
image on
the wheel notwithstanding that it is rotating.
The effect is achieved because with light flashes of very short duration, the
reaction
of the human eye to the flash persists long after the flash has finished.
Thus, where a series
of very short flashes occur over a short time span, less than 0.015 seconds,
all the flashes
appear to the eye to have occurred at the same time and when the flashes are
spaced from
one another on the retina, because the array has moved relative to the retina,
the eye
perceives a composite light pattern which will persist for a short while
immediately
following the time span. It will thus be appreciated that a program can be
created and
stored in the memory which will produce almost any desired image for the
observer. The
image may take the form of alphanumeric information or may take the form of an
advertising poster.

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This system has a number of limitations, namely to change the display the
cycle
must be halted and the control reloaded with a new program. Also, if both
front and rear
wheels are required to display images, there is no synchronisation between
them.
It is an object of the present invention to provide an improved display system
for
one or more wheels.
According to the present invention there is provided a wheel display system
for
producing an image display on one or more rotating wheels comprising
transmission means
at a central location and receiver means at a location associated with said
wheels, said
transmission means being arranged to transmit data representative of a desired
image to the
receiver means, local transmission means for transmitting data representative
of said
desired image to a local receiver arranged to be mounted on the or each said
wheel, a
radially extending array of light emitting devices arranged to be mounted on
the or each
wheel and control means for the or each wheel responsive to the data received
by the local
receiver to energise the light emitting devices in a sequence which as the
wheel rotates
results in an apparent image corresponding to said desired image.
A wheel display system, embodying the present invention, will now be
described,
by way of example, with reference to the accompanying diagrammatic drawings,
in which:
Figure 1 is a block diagram of the system;
Figure 2 is a rear view of a vehicle hub cap incorporating parts of the
system; and
Figure 3 is a section through the hub cap of Figure 2.

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The system to be described is arranged to provide a visual display on all four
wheels
of a taxi for advertising or other purposes with the image display being
transmitted from a
remote central control station. In this way, messages or advertisements can be
changed
almost instantaneously at will.
While the system is designed, in particular, for taxis, it will be appreciated
that it
can be applied to the wheels of other commercial vehicles, racing cars and
even private
vehicles.
The system shown in Figure 1 includes a central station 2 having a memory 4
for
storing data representing different images, a transmitter 6 with an associated
transmitting
antenna 8 and a control unit 10 having an input such as a keyboard which can
select any
desired image from the memory 4 and transmit it via the transmitter 6 and
antenna 8 to one
or more receiving stations 12. Each taxi has it own receiving station (only
one receiving
station being shown in Figure 1).
The receiving station has a receiver 12 and an associated receiving antenna
14.
The output of the receiver 14 is fed to a decoder 18 and through a gate 16 to
a
memory 20. The output of the decoder is connected to open and close the gate
16 in
response to receipt of open and close codes unique to that receiving station.
A control unit
22, when enabled, for example, in response to the taxi ignition being switched
ON,
downloads the data stored in the memory and causes the data to be transmitted
to an
auxiliary transmitter 24 for transmission to four auxiliary receiving units
30A to 30D
located one in each hub cap of the taxi.

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The four receiving units are similar and so only one will be described. The
receiving unit 30A has an auxiliary receiver 32A with an associated auxiliary
antenna 42A.
The output of the receiver 32A is downloaded into a memory 34A. A control unit
36A,
when triggered by closure of a reed relay switch 44A, accesses the memory unit
34A in
response thereto, energises selected ones of a new 38A of light emitting
diodes in a
sequence determined by the data stored in the memory. The rate at which the
diodes are
energised is determined by an oscillator (not shown) which has a frequency
that varies with
the rate at which the reed switch is closed.
A generator 40 mounted at the centre of the hub cap generates an AC signal
which
is full wave rectified and used to charge a rechargeable battery 42A. The
rechargeable
battery supplies power to the receiver 32A, the memory 34A, the control unit
36A and the
reed relay 44A.
As shown in Figure 2, mounted on the inside of the hub cap 52 are the
generator
40A at the centre, the array 38A of LEDs aligned with a radial slit 54 in the
hub cap so that
while they can be viewed from outside of the hub cap, they lie recessed within
the hub cap
so as to avoid being struck by foreign objects, the receiving unit 30A and the
reed relay
44A positioned at a location close to the outer perimeter. A magnet 50 for
triggering the
relay 44A to close, each time the relay 44A passes, is secured to the body of
the taxi for
example the wheel arch.
The generator 40A, as can be more clearly seen in Figure 3, comprises a stator
60
which is secured to the centre of the hub cap 54 by adhesive or mechanical
fastenings (not

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shown) to lie coaxial therewith, and a rotor 62. The rotor 62 carries a
relatively heavy
inertia disc 64. In operation, because taxis are continually accelerating and
decelerating,
there will be a resistance to delays in the rotor speed relative to the stator
speed because of
the inertial load on the rotor. This results in relative rotation between
rotor and stator and
will produce an alternating output voltage as with any generator of this type.
The output voltage is full wave rectified and limited (eg with a zenor diode)
and
used to maintain the rechargeable battery 42A charged.
In operation, when the control centre wishes to cause a taxi to generate a
particular
display on its hub caps, it will transmit data taken from the memory 4 and
representative of
that display together with a unique opening and closing code related to the
taxi in question.
While all the taxis in the relevant area will receive the transmitted data,
only the taxi with
the relevant diode 18 will respond and allow the transmitted data to pass
through the gate
16 into the memory 20.
The local control unit 22 in the taxi takes the data from the memory 20 and
transmits it to the four local receivers 30A to 30D for storage in respective
memories 34A
to 34D.
The control units 36A to 36D respond to the stored data to trigger the LED
arrays
38A to 38D in the appropriate sequences to reproduce the desired image on each
of the four
hub caps. The operation of the reed relays 44A to 44D ensure the correct
positioning of the
images on the hub caps and, by measuring the repetition rate of the relays,
any stretching or
contracting of the image with changes in speed of the hub caps can be
countered.

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It will be appreciated that while the local control unit 22 transmits the same
image
data to each wheel simultaneously, the auxiliary receivers can be provided
with a code
activated gate similar to the gate 16 so that they receive the same image at
different times or
receive different images at the same time.
While both the control and local transmitters are radio transmitters and
receivers
using cellular telephone or small packet switch techniques, it will be
appreciated that in the
case of the local transmitters and receivers, ultra sonic, inductive or
infrared
communication systems can be used instead.
Also, while all the display data is stored at the central control station,
each local
station can store all the data instead with the central station providing
command signals to
release from the local memories the desired image data when required.
Instead of the generator taking the form of a stator and rotor, it can be
replaced by
light cells or any other form of electrical generator.
While the image displayed on each wheel can be an apparently stationary one,
it can
also take the form of a moving image if the display data stored in the memory
is changed
every cycle or every few cycles.
In a modification, instead of the reed relay providing the trigger signal, it
might be
possible to derive the trigger signal from the generator when the generator
output includes a
component representative of a particular angular position.

Representative Drawing