GB2236885A

GB2236885A - Vehicle tyre fatigue warning device

Info

Publication number: GB2236885A
Application number: GB8921731A
Authority: GB
Inventors: Eric Greenslade
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-09-27
Filing date: 1989-09-27
Publication date: 1991-04-17
Also published as: GB8921731D0

Abstract

The device utilises an infra-red signal from an emitter 1 fitted to the rim of the vehicle wheel in circuit with twin sensors 6, 7 of pressure and temperature inside the tyre. An infra-red detector 5 with operating circuit is secured at a fixed location on the vehicle adjacent to the wheel and linked to a warning panel at the driving position. A modification to the tyre valve connector is made to provide pressure tight electrical continuity between the sensors inside the tyre, and the emitter and battery cell on the outside of the tyre. <IMAGE>

Description

TYRE FATIGUE WARNING SYSTEM This invention relates to tyre safety, and more particularly to the prevention of the disintegration of vehicle tyres as a result of tyre fatigue.

Tyre fatigue has become a recognised hazard for vehicles, particularly fully laden commercial vehicles, travelling on long distance motorway or trunk routes. If the fatigue becomes acute it leads to catastrophic tyre failure, which in the case of a front-wheel tyre can have fatal consequences.

Fatigue can occur for a number of reasons but the condition is characterised by either a decrease in tyre pressure below a safe minimum or a significant rise in tyre temperature or both. The driver is frequently not aware of the problem, particularly on a rear or trailer wheel, until the tyre fails catastrophically, as evidenced by the fragments of dismembered tyres bordering main traffic routes.

No system of warning appears to exist which alerts a driver of tyre fatigue or impending tyre failure.

According to the present invention there is provided a system for giving warning of vehicle tyre fatigue, comprising means for producing warning signals when the pressure and/or temperature within a vehicle tyre reach predetermined values, means for transmitting the warning signals to a detector adapted to be mounted on a part of the structure of a vehicle protected by the tyre fatigue warning system and means for producing alarm signals in response to the detection of the warning signals by the detector.

An embodiment of the invention will now be described, by way of example with reference to the accompanying drawings in which, Figure 1 is a schematic representation of an embodiment of the invention.

Figure 2 is an enlarged illustration of an electrical feedthrough incorporated in a tyre valve which is included in the embodiment of figure 1.

Referring to the drawings, and infra-red emitter device 1 is mounted on the rim 2 of each wheel of a vehicle, indicated generally by the numeral 3, so as to face towards a stationary part of an associated hub assembly 4 upon which is mounted an infra-red detector device 5 so that the emitter 1 and detector 5 are in juxtaposition once every revolution of the wheel 3.

A pressure sensitive switch 6 and a temperature sensitive switch 7 are mounted in a housing 8 which is attached to the inside of the rim 2 of the wheel 3 so as to be inside a tyre (not shown) fitted to the wheel 3. The switches 6 and 7 are connected in parallel with each other and in series with the emitter 1 so that a change in state of either, or both, of the switches 6 and 7 causes the emitter 1 to emit a warning signal. The switches 6 and 7 are set to operate when the pressure within the tyre falls, below, or the temperature within the tyre rises above, pre-set safety limits, respectively. The infra-red emitter device 1 is powered via the switches 6 and 7 by a battery 9 and an over-ride test switch 10 which, together with the infra-red emitter device 1 are contained in a waterproof housing 11.Connections to the switches 6 and 7 are made via a feed-through 12 which is inserted in a modified tyre valve 13. Of course, connection between the internal and external components of the system can be made through the rim 2 of the wheel 3, directly, if so desired.

The infra-red detector 5 is contained in a housing 14 which also contains a heater and a thermostat, not shown, to ensure that the temperature within the housing 14 is kept above a minimum value of 120C.

The heating circuit and the infra-red detector 5 are powered by the vehicle battery, which also is not shown. The infra-red detector 10 is connected to an audio/visual alarm display panel 15 in the cab of the vehicle. The alarm panel 15 has an indicator 16 for each wheel of the vehicle protected by the tyre fatigue warning system so that a driver of the vehicle is made aware of any tyre which is at risk of experiencing tyre fatigue.

Referring to Figure 2, the connector 12 which is inserted in the wall of the valve 13 of the vehicle tyre is shown in an exploded view. The connector 12 consists of la cone-shaped plug 21 made of an insulating material moulded around two wires 22 and 23. The wire 22 is attached to a metal plate 24 which has an insulating layer 25 bonded to its lower surface as shown in Figure 2. Also attached to the plate 24, is a lead 26. The wire 23 passes through a central hole 27 in the plate 24 and is attached to a second metal plate 28, to which there is attached also another lead 29.

The connector 12, is inserted into the wall of the valve 13, from the inside so that the pressure within the tyre tends to force the connector 12 in place and aids the maintenance of a pressure seal between the components of the connector 12 as well as between the connector 12 and the wall of the valve 13.

Claims

1. A system for giving warning of vehicle tyre fatigue, comprising means for producing warning signals when the pressure and/or temperature within a vehicle tyre reach predetermined values, means for transmitting the warning signals to a detector adapted to be mounted on a part of the structure of a vehicle protected by the tyre fatigue warning system and means for producing alarm signals in response to the detection of the warning signals by the detector.

2. A warning system according to claim 1 wherein the means for transmitting the warning signals is adapted to produce signals in the infra-red region of the electromagnetic spectra and the warning signal detector is adapted to detect such signals.

3. A warning system according to claim 1 or claim 2 wherein the means for producing the warning signals includes a pressure sensor and a temperature sensor adapted to be positioned within the vehicle tyre.

4. A warning system according to claim 3 wherein the means for transmitting the warning signal is adapted to be attached to the rim of a wheel to which the tyre is fitted.

5. A warning system according to any preceding claim including a valve by means of which the tyre may be inflated, the valve being adapted to provide electrical contact with the means for producing the warning signals.

6. A warning system according to any preceding claim wherein the means for producing alarm signals is adapted to produce aural signals.

7. A warning system according to any preceding claim wherein the means for producing the alarm signals is adapted to provide a visual indication of which of the tyres of a vehicle is at fault.

8. A warning system according to any of claims 2 and 7 wherein the warning signal detector is contained in a housing which is adapted to be maintained at a constant operating temperature.

9. A system for giving warning of vehicle tyre fatigue substantially as hereinbefore described and with reference to the accompanying drawings.