Vehicle tyre measurement

• US 8,625,105 B2
• Filed: 03/03/2010
• Issued: 01/07/2014
• Est. Priority Date: 03/03/2009
• Status: Active Grant

• Current Assignee: Snap-On Equipment S.r.l. (Snap-On Incorporated)
• Original Assignee: Sigmavision Ltd.
• Inventors: Pryce, Andrew, Gustafsson, Bjrn ke
• Primary Examiner(s): NGUYEN, SANG H
• Application Number:
  US13/254,319
• Publication Number:
  US 20120008148A1
• Time in Patent Office: 1,406 Days
• Field of Search: 356/139.09, 356/152.1, 356/152.2, 356/35.5, 356/601, 731/46, 731/520.5, 731/488, 250/559.19, 250/339, 250/341
• US Class Current: 356/601
• CPC Class Codes: G01B 11/22 for measuring depth
• CPC Class Codes: G01B 11/245 using a plurality of fixed, simultaneously operating transducers G01B11/2408 - G01B11/2425, G01B11/255 take precedence

Abstract

An apparatus measures the tread of a tire on a vehicle, in which a laser line generator (34) generates an elongate pattern of light. Mirrors (36) are arranged to reflect light from the laser line generator (34) onto the rolling surface of the tire. Mirrors (36, 38, 42) are arranged to reflect light from different regions of the rolling surface of the tire towards a camera (32). The camera images the regions of the rolling surface of the tire. The apparatus may be hand-held or arranged such that a tire to be aged is driven onto or over it.

Claims

1. An apparatus for measuring the tread of a tire on a vehicle comprising:

a light-emitting arrangement arranged in use to generate an elongate pattern of light;

a first reflecting arrangement arranged to reflect light from the light-emitting arrangement onto the rolling surface of the tire;

an imaging arrangement arranged to image a region of the rolling surface of the tire; and

a second reflecting arrangement arranged to reflect light from the rolling surface of the tire towards the imaging arrangement;

wherein the apparatus comprises a processor which generates data corresponding to a tread pattern of the tire; and

wherein at least one of the following arrangements are provided;

said first reflecting arrangement comprises two or more mirrors arranged to cooperate to reflect light from the light-emitting arrangement onto the rolling surface of the tire;

said second reflecting arrangement comprises two or more mirrors arranged to cooperate to reflect light from the rolling surface of the tire towards the imaging arrangement; and

said first reflecting arrangement comprises two or more mirrors arranged to cooperate to reflect light from the light-emitting arrangement onto the rolling surface of the tire and said second reflecting arrangement comprises two or more mirrors arranged to cooperate to reflect light from the rolling surface of the tire towards the imaging arrangement.

2. An apparatus as claimed in claim 1 which is a portable sensor unit and which is suitable for determining tread depth of a tire mounted on a wheel installed on the axle of a vehicle.

3. An apparatus as claimed in claim 2, wherein the imaging arrangement and at least one of said reflecting arrangements are arranged such that, when the unit is in use, they are situated between the two planes containing the respective sidewalls of the tire.

4. An apparatus as claimed in claim 1, wherein said processor is further configured to generate data corresponding to tread depth for the tire mounted on a wheel installed on the axle of a vehicle when said vehicle is driven onto or over said apparatus.

5. An apparatus as claimed in claim 4 comprising a ramp for lifting a wheel of the vehicle.

6. An apparatus as claimed in claim 4 wherein said first reflecting arrangement is arranged to reflect light upwards towards the surface of the tire.

7. An apparatus as claimed in claim 4 wherein said first reflecting arrangement is arranged to reflect said light towards the surface of the tire at an angle of less than 45 degrees to the vertical.

8. A method as claimed in claim 4 wherein said first reflecting arrangement is arranged to reflect said pattern of light so that the light strikes the tire surface at an angle of less than 45 degrees to the normal.

9. A method as claimed in claim 4 wherein the first and second reflecting arrangements are arranged such that the angle at which light reaches the imaging arrangement differs from the angle at which said pattern of light from the light-emitting arrangement reaches the tire surface.

10. An apparatus as claimed in claim 1 comprising one or more rollers arranged to engage the vehicle tire.

11. An apparatus as claimed in claim 1 comprising a window arranged such that light passes through the window when travelling to the tire surface and when travelling from the pattern on the tire towards the imaging arrangement.

12. An apparatus as claimed in claim 1 comprising a laser arranged to project an elongate pattern of light onto the tire surface.

13. An apparatus as claimed in claim 1 wherein said mirrors are at least 90% of the length of the elongate pattern of light.

14. An apparatus as claimed in claim 1 comprising first and second imaging arrangements arranged in use to image respective first and second regions of the rolling surface of the tire, the first region extending further towards the inner sidewall of the tire than does the second region.

15. An apparatus as claimed in claim 14 wherein the first reflecting arrangement comprises a reflecting surface substantially centered within the field of view of the first imaging arrangement in a direction parallel to the wheel axis.

16. An apparatus as claimed in claim 15 wherein a plurality of said reflecting surfaces are provided by a single faceted reflector.

17. An apparatus as claimed in claim 14 wherein the second reflecting arrangement comprises a second reflecting surface located to one side of the field of view of the first imaging arrangement in a direction parallel to the wheel axis.

18. An apparatus as claimed in claim 17 comprising a further reflecting surface located symmetrically to the second reflecting surface about a central axis in the field view perpendicular to the wheel axis, and arranged to reflect light received indirectly from the surface of the tire directly to the first imaging arrangement.

19. An apparatus as claimed in claim 1 comprising a further imaging arrangement arranged to image one or both of the shoulders or sidewalls of the tire.

20. An apparatus as claimed in claim 19 comprising a light-guiding arrangement arranged to direct light from one or both of the shoulders or sidewalls of the tire towards said further imaging arrangement.

21. A method of measuring the tread of a tire on a vehicle comprising:

generating an elongate pattern of light from a light-emitting arrangement;

using a first reflecting arrangement to reflect light from the light-emitting arrangement onto the rolling surface of the tire;

using a first reflecting arrangement to reflect light from the rolling surface of the tire towards imaging arrangement; and

imaging a region of the rolling surface of the tire;

generating, in a processor, data corresponding to a tread pattern of the tire;

wherein at least one of the following arrangements are provided;

said first reflecting arrangement comprises two or more mirrors arranged to cooperate to reflect light from the light-emitting arrangement onto the rolling surface of the tire;

said second reflecting arrangement comprises two or more mirrors arranged to cooperate to reflect light from the rolling surface of the tire towards the imaging arrangement; and

said first reflecting arrangement comprises two or more mirrors arranged to cooperate to reflect light from the light-emitting arrangement onto the rolling surface of the tire and said second reflecting arrangement comprises two or more mirrors arranged to cooperate to reflect light from the rolling surface of the tire towards the imaging arrangement.

22. A method as claimed in claim 21 comprising imaging said region of the rolling surface of the tire whilst the tire is located above an apparatus adapted to carry out said generating, reflecting and imaging steps.

23. A method as claimed in claim 22 comprising reflecting light upwards towards the surface of the tire.

24. A method as claimed in claim 22 comprising reflecting light towards the surface of the tire at an angle of less than 45 degrees to the vertical.

25. A method as claimed in claim 22 comprising reflecting light so as to strike the tire surface at an angle of less than 45 degrees to the normal.

26. A method as claimed in claim 22 wherein the angles at which light forming the pattern on the tire surface reaches the imaging arrangement differ from the angle or angles at which light from the light-emitting arrangement reaches the tire surface.

27. A method as claimed in claim 22 comprising reflecting light from the light-emitting arrangement simultaneously onto the rolling surfaces of a plurality of tires.

28. A method as claimed in claim 21 further comprising the step of using said measurement of tire tread automatically to diagnose tire, vehicle or driver faults or to predict a remaining service life of the tire.