GB2117516A

GB2117516A - Measuring distances travelled by non-powered wheeled vehicles

Info

Publication number: GB2117516A
Application number: GB08307692A
Authority: GB
Inventors: Edward Jackson Diggs
Original assignee: Rubery Owen Rockwell Ltd
Current assignee: Rubery Owen Rockwell Ltd
Priority date: 1982-03-26
Filing date: 1983-03-21
Publication date: 1983-10-12
Also published as: GB8307692D0

Abstract

A wheel and axle assembly of a non-powered wheeled vehicle includes electrically powered signalling means 7 on a non-rotating part 6 of the assembly arranged to respond to a part 8 which rotates with the wheel and feeds signals to a recording mechanism 13 which processes the signals for display of the distance travelled by the vehicle as a function of the revolutions of the rotatable part. The recording mechanism is situated at any suitable position on the vehicle remote from the signalling means, which is conveniently housed within a brake drum. The signalling means may be the sensor of an anti- skid system which responds to an exciter rotatable with the wheel. <IMAGE>

Description

SPECIFICATION Improvements relating to the measuring of distances travelled by non-powered wheeled vehicles This invention relates to measuring of the distance travelled by non-powered wheeled vehicles, more particularly, though not exclusively, road vehicles such as trailers and semi-trailers.

Towed vehicles, generally have one or more axles with free running wheels, have no driven axle and are releasably coupled to a tractor unit for use in the transport of goods. Towed passenger vehicles are also known. The current practice with towed vehicles, where it is desired to measure distances travelled, is to fit a mechanical odometer to a wheel hub. This has a number of disadvantages, including accessibility for reading and vulnerability to damage. Mechanical odometers protrude beyond the axles to which they are applied and can cause the vehicles to be beyond the legal width limits. Also they are individual to particular wheel and tyre combinations so that there can be no universal model, and no trip distance indication is available.

According to one aspect the present invention consists in a non-powered wheeled vehicle having a ground engaging wheel and axle assembly, signalling means on a non-rotating part of the assembly adjacent to a part thereof which rotates when the vehicle is in motion, an electrically powered recording mechanism on the vehicle, the signalling means and the recording mechanism being adapted for connection to an electric power source, or respective power sources, and conductor means extending between the signalling means and the recording mechanism, the arrangement being such that with the recording mechanism and signalling means connected to an electric power source, or to respective power sources as the case may be, the signalling means responds to rotation of the said rotatable part whereby signals are generated and fed by the conductor means to the recording mechanism which processes the signals for display of the distance travelled by the vehicle as a function of the number of revolutions of the rotatable part.

The signalling means may comprise a proximity switch, for example of the inductive or of the capacitive type. A target for causing operation of the switch may be secured to or be integral with a ring secured to a rotating part of the wheel and axle assembly, for example a wheel hub or a brake disc.

The vehicle may include an anti-skid braking system a sensor of which is fitted to the wheel of the assembly and serves also as the signalling means, and an exciter of which activates the sensor for the duel purposes of the anti-skid system and counting the revolutions of the wheel.

The recording mechanism may be fitted at any convenient location on the vehicle. It may include a display which gives cumulative journey distances and trip distances, means being provided to set the trip distance display to zero at commencement of a journey, and a calibration control which is settable to provide an input signal to the recording mechanism which is a function of the tyre rolling radius of the wheel of the assembly enabling the indication on the display of distance travelled to be given in convenient units. Provision may be made for selecting alternative units of distance measurement for display, as for example miles or kilometres.

The recording mechanism may be adapted for connection to a battery on a tractor unit by which the non-powered wheeled vehicle is to be towed when in use. A battery for supplying the mechanism may be provided on the non-powered vehicle if desired.

In the latter case it may be desirable to provide a battery state indicator. Provision may be made for charging such a battery, for example with the use of photo-voltaic cells.

According to a further aspect the invention consists in a method of recording the distance travelled by a non-powered wheeled vehicle having a ground engaging wheel and axle assembly comprising the steps of providing an electrical input to signalling means carried by a non-rotating part of the wheel and axle assembly adjacent to a rotating part thereof, taking signals which are a function of the number of revolutions of the wheel from the signalling means and feeding them to a recording mechanism which causes a display to be made of the distance travelled as a function of the number of revolutions of the wheel.

The vast majority of known towed vehicles are currently fitted with internally expanding shoe and drum brakes. The non-powered wheeled vehicle according to the present invention may have such brakes and the signalling means may conveniently be located within the confines of a drum of one of the brakes where it is protected from physical damage and is tamper-proof.

The use of a proximity switch as the signalling means is particularly advantageous because it is free from wear and requires no maintenance.

An embdimentofthe invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is an outline drawing of a semi-trailer in accordance with the present invention, and Figure 2 is a diagrammatic axial section through a brake drum of the semi-trailer showing signalling means.

Referring to the drawings, a semi-trailer 1 has twin axles 2, only one of which is shown, each having a single wheel 3 at each end. Each wheel 3 is mounted on a hub 4 to which a brake drum 5 is also secured in known manner. The open inner end of each brake drum 5 is closed by a dust cover, not shown, secured to a brake anchor bracket 6 which is mounted on the respective axle 2. The hub 4 of each wheel is carried on bearings (not shown) on the end of the axle 2 so as to be rotatable relative thereto.

Within the brake drum of one of the wheels a proximity switch 7 is secured to the brake anchor bracket 6 and directed towards a ring 8 secured to the hub 4. The ring 8 incorporates a suitable target (not shown) for causing the switch 7 to operate. For example, if the switch 7 is normally open, then as the target passes across it with each revolution of the wheel the switch is caused to close momentarily and then re-opens. The reverse occurs if the switch is of the normally closed type. There may be more than one target on the ring, in which case there will be more than one signal for each revolution of the wheel. An electrical socket 9 at the front of the trailer can receive a supply from a plug connected to a battery on a tractor unit.

Conductor means 11, 12 connect the socket to an electronic digital recording mechanism 13 and to the switch 7 whereby signals from the switch are fed to the recording mechanism where they are processed and fed to a display which records distance travelled.

The recording mechanism 13 may be of a known kind which includes a display and provision for applying a multiplying constantwherebyadjustment may be made for different tyre rolling radii and for conversion of the count to convenient units of distance, for example miles or kilometres as required.

In order to retain the record of distance travelled when the socket 9 is disconnected, a battery (not shown) may be carried by the trailer and connected to the conductor means 11, 12. This may be kept in, or restored to, a charged condition automatically by an array of photo-voltaic cells also mounted on the trailer. Alternatively, or in addition, means may be provided for charging the battery from an external source.

It will be appreciated from the foregoing that the present invention enables the provision of a remote reading odometer on a non-powered wheeled vehicle at a convenient location and when the vehicle is fitted with a drum brake, the signalling means may be located within the drum where it is protected from physical damage and is tamper proof. Itwill be understood, however, that the invention may also be used on a non-powered wheeled vehicle fitted with disc brakes but in that case it is more difficult to iocate the signalling means so that it is protected from physical damage.

Claims

1. A non-powered wheeled vehicle having a ground engaging wheel and axle assembly, signalling means on a non-rotating part of the assembly adjacent to a part thereof which rotates when the vehicle is in motion, an electrically powered recording mechanism on the vehicle, the signalling means and the recording mechanism being adapted for connection to an electric power source, or respective power sources, and conductor means extending between the signalling means and the recording mechanism, the arrangement being such that with the recording mechanism and signalling means connected to an electric power source, or to respective power sources as the case may be, the signalling means responds to rotation of the said rotatable part whereby signals are generated and fed by the conductor means to the recording mechanism which processes the signals for display of the distance travelled by the vehicle as a function of the number of revolutions of the rotatable part.

2. A non-powered wheeled vehicle as claimed in claim 1 wherein the signalling means comprises a proximity switch which responds to a target on a ring rotatable with the rotating part.

3. A non-powered wheeled vehicle as claimed in claim 1 including an anti-skid braking system in which a sensor responds to an exciter, and wherein the signalling means is the sensor.

4. A non-powered wheeled vehicle as claimed in any preceding claim including a re-chargeable power source and means for re-charging the power source.

5. A non-powered wheeled vehicle as claimed in claim 4 wherein the means for re-charging comprises photo-voltaic cells.

6. A non-powered wheeled vehicle as claimed in any proceding claim wherein the rotating part is a wheel hub.

7. A non-powered wheeled vehicle as claimed in any preceding claim wherein the rotating part is a brake disc.

8. A non-powered wheeled vehicle as claimed in any preceding claim wherein the recording mechanism includes a display giving cumulative journey distances and trip distances, means being provided to set the trip distance display to zero at commence ment of a journey.

9. A non-powered wheeled vehicle as claimed in any preceding claim wherein the recording mechanism includes a calibration control which is settable to provide an input signal to the recording mechanism which is a function of the tyre rolling radius of the wheel of the assembly enabling the display indication to be given in convenient units of distance measurement.

10. A non-powered wheeled vehicle as claimed in claim 9 wherein the recording mechanism includes a second control selectable to cause display of distance travelled alternately in miles or kilometres.

11. A method of recording the distance travelled by a non-powered wheeled vehicle having a ground engaging wheel and axle assembly comprising the steps of providing an electrical input to signalling means carried by a non-rotating part of the wheel and axle assembly adjacent to a rotating part thereof, taking signals which are a function of the number of revolutions of the wheel from the signalling means and feeding them to a recording mechanism which causes a display to be made of the distance travelled as a function of the number of revolutions of the wheel.

12. A non-powered wheeled vehicle substantially as described herein with reference to the accompanying drawings.