GB2395791A

GB2395791A - Electronic tyre inspection system

Info

Publication number: GB2395791A
Application number: GB0122480A
Authority: GB
Inventors: Frank David Watts Charlesworth
Original assignee: CHARLESWORTH FRANK; Aspentine Ltd
Current assignee: CHARLESWORTH FRANK; Aspentine Ltd
Priority date: 2001-09-18
Filing date: 2001-09-18
Publication date: 2004-06-02
Anticipated expiration: 2021-09-18
Also published as: GB0122480D0; GB2395791B

Abstract

A method and means of tyre inspection comprises positioning an electrode 9 inside a tyre 6 and an electrode outside said tyre and providing a liquid between the surface of the tyre 6 and the said electrodes. The liquid may be water provide in a water tank 4, into which the tyre 6 may be partially immersed. An alternating voltage may be applied to the electrodes and signals relating to the electrodes may be analysed by a computer. A tyre supporting frame, hoist, rollers 7 and position encoder arrangement may be employed to move the tyre 6 past the electrodes such that they scan the tyre, from one sidewall to the other. The signals may then be used to create a two dimensional map of the holes, cuts and debris present in the tyre. This information may then be used to decide if the tyre is repairable and how to repair it.

Description

239579 1

1. ELECTRONIC INSPECTION SYSTEM FOR TEIE DETECTION

OF PENETRATIONS Apt) PARTL4L PENETRATIONS IN PNEUMATIC TYRES.

Dr.F.Charlesworth of Aspentine Limited a British company of c/o Technic Systems Ltd. Castle Lane, Melbourne, Derbyshire, DE73 IDY do hereby declare the invention, for which we hope a patent to be granted to us, and the method by which it is to be performed, to be particularly described in the following statement.

The present invention relates to a tyre inspection system, and in particular to a tyre inspection system adapted to locate nails, nail holes, cuts, partial penetrations with or without metallic debris present within the tyre structure using an electronic device.

Nail holes and penetrations within the composite structure of vehicle tyres are well known problem in the tyre industry. Car, truck aircraft and earthmover tyres are commonly retreaded and should be inspected before retreading to ensure the integrity of the tyre structure. Failure to do so can result in the retreading process being seriously flawed.

The use of electronic energy to probe the internal structure of the tyre has already been proposed in the art. EIowever the prior art

systems have all suffered from various drawbacks, in coverage of the inspection. Normally shoulder to shoulder of the tyre, speed and ease of inspection and interpretation.

It is an objective of the present to provide at reasonable cost a reliable user friendly device which supplies simple clear displays of holes and penetrations in the composite structure of the tyre, scanning shoulder to shoulder and covering the lower part of the sidewall of the tyre being inspected. It is a further objective of the present invention to provide an inspection apparatus which provides a two dimensional map clearly indicating any holes or penetrations, in real time as the scan is progressed. It is also an objective to be able to identify suspect areas and physically locate them at a pre determined position for visual examination.

This invention relates to the finding of holes and penetrations in the composite structure of truck, car, aircraft and earthmover tyres.

Means for providing a liquid medium between internal and external

2. sensors. The method uses low voltage excitation from the sensor in water inside the tyre to create a circuit through the hole or penetration via the water in the outside tank to a corresponding sensor outside the tyre. Due to the use of AC voltage and capacitive coupling it is also capable of detecting partial penetrations. The energy is sampled as the tyre is rotated and the scanned levels of energy is displayed in real time on a computer screen.

The key features of the electronic design are 1. The use of AC voltage.

2. phase rejection.

3. The utilization of capacitive coupling.

4. Sensitive highly stable electronics with very low noise and advanced filtration.

5. Electrical leakage control to prevent signals due to alternative current paths between the sensors inside and outside the tyre.

The present invention will now be described in detail by way of example and with reference to accompanying drawings in which, with reference to figure 1 there is shown a preferred embodiment of a tyre inspection apparatus 1 according to the present invention. It is also envisaged that the embodiment can also be applied to other tyre inspection apparatus. The tyre inspection apparatus comprises a tyre scanning unit 2 and an analysis and display unit 3.

The Are scanning unit 2 comprises a four sided tank 4 and a frame 5 supporting the tank. A vehicle tyre 6 may be mounted in the tank using the pneumatically powered crane 8 with its conventional axis of rotation horizontally disposed and traverse to the tank, by positioning the bead surface on two rollers 7. The frame 5 supports positioning means which are adapted to position (1). The internal sensor 9 is introduced into the water on the inside of the tyre and where there is a nail hole or penetration through the tyre structure 10 energy will be transferred via the water from the inside of the tyre through the penetration to the corresponding sensor in the tank on the outside of the tyre.

he tyre is rotated icy means of an electric motor i 1 driving one of the rollers 7. An encoder either optical or electrical is also attached to the roller 7 to provide an electrical input which indicates the circumferential position of the tyre. The frame I and the display unit

3. 3 including electronic generator and VDU are connected by bunking 12. This also provides a motor control drive for the roller motor.

In use the tyre S placed in the tank 4 by posit:ón:ng it on rollers 7 attached to the pneumatically operated crane 8 and lowered into the water. As the tyre is lowered into the water it will automatically fill with water. The depth location location of the tyre in the water is contolled by adjustable pin 13. The inside sensor is introduced to the inside of the tyre and locates automatically in the correct central position within the tyre. The apparatus is designed to accommodate tyres of various sizes. By moving pin 13 the level at which the tyres of varying sizes can be located at the required inspection positions.

The analysis display unit 3 which includes a suitably programmed computer system 14 interfaced with analogue instrumentation unit and control unit () 15 provides all the necessary control analysis and display functions for the tyre scanning unit 1. The control unit 15 also includes connector 16 for the motor drive, the analogue instrument unit includes connectors 17 and 18 for the connections to the inside and outside sensors for the device. Connector 19 is for the encoder output.

With reference to figure 2, the functionality of the analysis and display unit 3 will now be described. A generator 15 supplies electrical voltage between the inside sensor 9 and the outside sensors 20 via connections 17 and 18. Normally a tyre with no penetrations the sensors will not be excited, but where a penetration 10 exists the sensors will be excited and electrical current will pass between the inside and the outside sensors. Also because of the AC excitation voltage and hence the capacitive coupling partial penetrations will be detected. When electrical signals are received by the connections 17 and 18 they are fed into a programmable gain amplifier 21, then a rectifier 22 and finally a filter 23 which precondition the received signal ready for converting into digital amplitude signals by the analogue digital converter (ADC) 24, such signal processing techniques are well known in the art, and need not be discussed in detail here. During the supply of power to the sensor and connector, the motor drive 25 in conjunction with the apparatus described above, is operative to rotate the tyre about its conventional axis of rotation.

4. The computer system 14 includes an interface bus 26 which is used to read the output from the ADC 24 and store the value for ready display. The encoder 27 output is provided to an encoder conditioning and timing (ECT) circuit 28, which is also connected to the interface bus 26. The ECT circuit provides a digitised signal representing the circumferential position of the tare.

In use the computer 14 is programmed to enter a data acquisition routine and awaits an interrupt from the encoder conditioning and timing circuit. Upon receiving the interrupt 5 the computer reads, over the bus 26, the encoder position information, and the received signal amplitude from the ADC 24. These two items are stored in corresponding predetermined memory positions. While awaiting a further interrupt from the ECT circuit 28 and displays the new pixel information on the VDU screen 29. Thus the details of the tyre inspection is built up in real time, as the scanning unit 1 scans the tyre 6.

The computer is preferably provided with a database of the standard tyre sizes from which it is able to compute the circumferential distance to be travelled before completion of the whole tyre. Thus the operator need only indicate the size of the tyre being scanned.

The computer system is preferably adapted to display, on screen 29, a two dimensional image of the scan sidewall to sidewall.

Alternatively, the results of the tyre scan may be displayed as a printed hard copy or saved to disk for later viewing.

There is also a positioning feature to return the defective area to a known position. To select this using the mouse curser click on the suspect area. You can choose where the suspect area is to be physically positioned for visual inspection.

Once detected the penetration can be assessed for suitability for repair. If possible the repair can be carried out but i! the damage is severe the tyre casing may be discarded.

Claims

5. CLAIMS

1. A tyre inspection apparatus for detecting holes and penetrations in the composite structure sidewall to sidewall of a Are bemg scanned comprising: Positioning means for positioning an electronic sensors to scan the tyre for penetrations. Means for providing a liquid medium continuous between the inside sensor and its proximal face of the tyre, and continuous between the proximal face of the tyre and the outside sensor. A generator to produce a voltage and an analyser to analyst the received signals.

2. A tyre inspection apparatus according to claim 1 in which the positioning means is adapted to locate the inside sensor " proximal to the inside of the Are face and the external sensor proximal to the outside of the tyre face.

3. A tyre inspection apparatus according to claim 2 including means for retaining a tyre with its conventional axis of rotation horizontal, thereby having at least part of the tread facing in a downward direction, in which positioning means inside sensor locatffon extending into the cavity of the tyre. The sensor being in a fixed relationship to inspect the tyre sidewall to sidewall with corresponding sensors on the outside of the tyre.

4. A tyre inspection apparatus according to any preceding claim in which the positioning includes means for rotating the tyre past an inspection point.

S. A tyre inspection apparatus according to any preceding claim includes a swing hoist for loading and unloading the lyre.

6. A tyre inspection apparatus according to any previous claim including at least one encoder device to determine the relative position of the tyre circumferenffal:y.

7. A tyre inspection apparatus according to any preceding claim in which means for providing a liquid medium continuous

6. between the inside sensor, the tyre and the outer sensor comprising a tank for containing liquid in which the tyre can be mounted and partially immersed condition and with its conventional axis of rotation horizontal.

8. A tyre inspection apparatus according to claim 7 including a plurality of rollers on the hoist adapted to rotate the tyre aboiit its conventional axis of rotation.

9. A tyre inspection apparatus according to any preceding claim in which the positioning means is adapted to scan the tyre with a plurality of scans. Each scan position circumferentially displaced from the preceding scan, and in which the analyser is adapted to construct a two dimensional map of the running surface and sidewalls of the tyre.

10. A tyre inspection apparatus according to claim 9 further including a display unit adapted to display the two dimensional map in real time as the tyre is being scanned.

11. A tyre inspection apparatus according to claims 9 and 10 in which the two dimensional map is adapted to show and highlight holes and penetrations.

12. A tyre inspection apparatus substantialb as described herein with reference to the accompanying drawings.

13. A method of inspecting lyres for the detecting holes and penetrations in the composite structure of the tyre, the method comprising the steps of: Positioning the electronic sensors to allow, when there is a penetration, energy to pass through the vehicle tyre, interposing a liquid medium continuous the tank sensor and its respective proximal face of the tyre; generating a current by the generator and when the circuit is completed analysing the signal.