GB2336435A

GB2336435A - Electronic odometer

Info

Publication number: GB2336435A
Application number: GB9904273A
Authority: GB
Inventors: William Edward Davies
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-02-24
Filing date: 1999-02-24
Publication date: 1999-10-20
Also published as: GB9904273D0; GB9803851D0; GB0020937D0; WO1999044017A1; GB2350198A; AU2631799A

Abstract

An odometer for e.g. a trailer comprising a display, a sensor capable of sensing a measure of the distance travelled by the trailer and emitting a signal representative of that measure, a controller which operably converts the measured signal into data representative of the current or trip distance travelled, a memory for storing data representative of a cumulative distance travelled by the trailer, and wherein the processor is adapted to add the current distance data to the cumulative distance data from the memory to provide a new cumulative distance value which is operably shown on the display. The odometer also includes means for calibration due to wheel size, means to input the number of sensor pulses which will constitute a single revolution of a wheel, and means to conserve power if the vehicle is stationary for a certain time.

Description

1 ODOMITER 2336435 The invention relates to an odometer and in particular

an odometer for use on a trailer such as used on artic lorries by hauliers.

Vehicle trailers are used to haul goods for long distances for example between different depots. It is important for the owner of the trailer to keep track of the total distance travelled by a trailer and it is known to fit a mechanical odometer to such traders. However, such odometers can be unreliable, can be too easily reset or altered thereby losing accurate information about the distance travelled by the trailer, and require a separate light source for example for viewing at night.

The invention seeks to mitigate these and other problems of the prior art and provide an improved odometer. According to one aspect of the invention there is provided a odometer for a trailer comprising a display, a sensor capable of sensing a measure of the distance travelled by the trailer and emitting a signal representative of that measure, a controller which operably converts the measure signal into data representative of the current distance travelled, a memory for storing data representative of a cumulative distance travelled by the trailer, and wherein the processor is adapted to add the current distance data to the cumulative distance data from the,.mory to provide a new cumulative distance value which is operably shown on the display.

Beneficially such an odometer can be installed on a trailer by an original equipment manufacturer or retro-fitted to a trailer.

2 Beneficially, the system can have low power consumption and therefore run off a battexy. However, preferably the battery is also charged from a current source such as that provided for operating the trailer running lights such as brakes and night lights.

0 Another aspect of the invention provides a trailer having an odometer with a display, control means and a sensor for detecting a measure of the distance travelled by the trailer, wherein the control means operably effects display of distance information on the display based on the sensor measurements.

Beneficially the control means and display can be housed in a single box and the sensor positioned remote therefrom, for example adjacent a wheel.

A preferred embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, 0 FIGURE 1 is a schematic block diagram of components of an odorneter according to the invention; and FIGURE 2 is a schematic drawing of a sensor fitted to a reel plate of a trailer.

Referring to Figure 1, there is shown an odometer 10 comprising a sensor c 12 such as an inductive sensor which can be triggered once per revolution of a wheel. For example this can be achieved by attaching a piece of metal in a suitable position to the wheel so that it passes close to the sensor once per revolution. Alternatively, part of an ABS sensor system can be used which comprises typically about 60 irregularities in the perimeter of the wheel hub H.

3 The irregularities can be apertures in a metal plate or a toothed wheel, both of which effect a repeat signal to be generated at the sensor. Acordingly, in such a system more than one pulse (actually 60 in this example) are generated by the sensor 12 per revolution of the wheel.

The output from the sensor 12 goes through a differential amplifier 14 0 which in turn sends an output signal to a comparator 16. If a signal from the sensor 12 representative of a wheel revolution is seen by the comparator 16, it sends an output signal to timer 18.

Timer 18 comprises a monostable one shot device and a timer circuit such as a resistance capacitance circuit to provide a suitable output signal from timer 18 for a sustained period such as ten minutes. Accordingly, timer 18 will produce a suitable output signal to enable power to the rest of the circuit for up to say ten minutes after a signal isamitted from sensor 12.

The appropriate signal from timer 18 causes power switch 20 to effect power transfer from battery 22 which is fed to a power line 24 to pass to microcontroller 26 and display 28- The microcontroller 26 can for example be a PIC 16C84 Arizona Technologies IVEcrocontroller and display 28 can for example be a liquid crystal display with a back light 30.

Nlicrocontroller 26 comprises an onboard memory in the form of an eprorn which is used for storing ctive distance travelled data. The distance travel data is calculated by the, microcontroller 26 based on input from size selector 31 which comprises multiple switches to enable an installer or factory engineer to calibrate the system. The selector 31 is set according to the me-an 4 diameter of a trailer tyre over its lifetime. By appropriate selection of a value at selector 31, microcontroller 36 is used to determine the distance travelled by a trailer based on the number of signals emitted by sensor 12 via amplifier 14 and comparator 16. Ibus, microcontroller 26 is able to calculate a value for the current or a trip distance travelled which data is added to the cumulative distance travelled by the trailer and stored in the eprom. The new cumulative distance is also displayed at display 28. Selector 31 can also be used to input the number of pulses which are generated at sensor 12 per revolution of the wheel, and which are therefore to be expected by microcontroller 36.

A circuitry for odometer 10 further comprises a clock 32 reset switch 34 and brown out detector 36. The reset switch 34 enables the cumulative distance status stored in the eprom to be erased. The brown out detector 36 determines if the voltage to the microcontroller is below a critical value. In the event that the voltage drops too low, the detector 36 resets the microcontroller.

In order to mitigate against loss of power to odometer 10, a rechargeable battery is preferably used. Battery 22 can be a nickel cadmium 12 volt battery. Battery 22 preferably is connected to a current source such as the trailer lights 38 via a current lirniter 40 to enable new recharging of the battery 22 when tile trailer lights are in use.

Referring to Figure 2, it can be seen that odometer 10 can comprise a controller circuit 44 and display 28 which can be housed in a single box for attachment to a trailer in a convenient location. Controller circuit 44 can comprise all of the elements shown in Figure 1 except sensor 12. Sensor 12 is preferably attached to a wheel rear plate such as Rubery Owen backplate typically used on trailers. It can be attached at an existing aperture in the back plate P or via a bracket 46 to the perimeter of back plate P. Preferably a piece of metal B is attached to pan of the hub H direct so that the piece of metal B passes close to sensor 12 on each revolution of the wheel.

Beneficially therefore the odometer 10 can be factory fitted to a trailer or retrofitted by use of a bracket 46.

A farther benefit of the system is that in the event that the vehicle is stationary for more than a predetermined time, such as ten minutes, the output from timer 18 changes and power switch 20 operates to cut off power to the inessential elements such as microcontroller 26 and display 28 of the odometer 10. However, power is preferably continuously provided by battery 22 to sensor 12, differential amplifier 14 comparator 16 and timer 18 such that in the event that the vehicle moves again, a signal detected by sensor 12 is amplified by differential amplifier 14, and a suitable output from comparator 16 causes timer 18 to switch output and accordingly actuate power switch 20 again.

Additionally, a manual switch 42 is preferably provided which would enable an inspector to actuate switch 42 thereby to switch timer 18 and power up microcontroller 26 and display 28-to provide a display of the distance travelled by the trailer. Beneficially ther, a driver or other inspector can check the distance travelled by the trailer y after stopping the vehicle, or switch 42 can be used at a later time, for le at night, for someone to check the distance travelled some time after t4 vehicle.

6 G An odometer for a trailer comprising a display, a sensor capable of sensing a measure of the distance travelled by the trailer and emitting a signal representative of that measure, a controller which operably converts the measure signal into data representative of the current or trip distance travelled, a memory for storing data representative of a cumulative distance travelled by the trailer, and wherein the processor is adapted to add the current distance data to the cumulative distance data from the memory to provide a new cumulative distance value which is operably shown on the display.

Claims

2. An odometer according to Claim 1 comprising a power supply such as a

battery.

An odometer according to Claim 2 wherein the power supply is adapted to transfer current to the odometer from an external current source.

4. An odometer according to any preceding claim comprising a user input enabling input of individual trailer parameters such as mean circumference of a wheel.

5. An odometer according to any preceding claim comprising a user input enabling input of sensor characteristics such as the number of pulses which are aenerated per revolution of the wheel.

6. An odometer according to any preceding claim comprising a timer delay which effects a power shut off to predetermined electrical components, forming part of the odometer, a predetermined time after the last detected pulse from the sensor.

An odometer according to any preceding claim comprising a switch operable to enable a user to view the cumulative distance travelled on the display independent of when the trailer last moved.

7.

7 8. A trailer having an odometer with a display, a controller and a sensor for detecting a measure of the distance travelled by the trailer, wherein the controller operably effects display of distance information on the display based on the sensor measurements.

9. A trailer according to Claim 8 wherein the controller and display are housed together and the sensor is positioned remote therefrom, for example adjacent a wheel.

10- An odometer substantially as described herein with reference to Figures 1 and 2.