GB2269347A

GB2269347A - Pneumatic tyre tread depth indicator.

Info

Publication number: GB2269347A
Application number: GB9216553A
Authority: GB
Inventors: Harold Henry Crump
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-08-04
Filing date: 1992-08-04
Publication date: 1994-02-09
Also published as: GB9216553D0

Abstract

A tread depth indicator 14 is located within a pneumatic tyre and is coloured bright yellow, or an alternative colour, for a precise depth of 1.59 millimetres for category A pneumatic tyres and 0.99 millimetre for category B pneumatic tyres measured vertically from a datum point 16, at the base of a tread groove, throughout a continuous band around the tyre's circumference comprising the central three-quarters 15 of the breadth of tread. Category A tyres are for cars, light goods vehicles and light trailers; category B tyres are for heavy goods vehicles, buses and motorcycles. <IMAGE>

Description

PNEUMATIC TYRE TREAD DEPTH INDICATOR.

This invention relates to a Pneumatic Tyre Tread Depth Indicator.

The new standard on minimum tread depths set by European Community Directive 89/459/EEC which was agreed at the Council of Transport Ninisters in June 1989, relating to cars, light goods vehicles and light trailers specifies that: "The grooves of the tread pattern shall be of a depth of at least 1.6 millimetre throughout a continuous band comprising the central threequarters of the breadth of tread and round the entire outer circumference of the tyre." The current U.K standard for tyres on lorries, buses and motorcycles is a minimum of 1 millimetre of tread in a continuous band across threequarters of the tread pattern with visible tread on the remaining quarter.

NOTE: Throughout this Patent Application: Category A refers to cars, light goods vehicles and light trailers.

Category B refers to heavy goods vehicles, buses and motorcycles.

The vast number of pneumatic tyres that are available for use on Britain's public highways resulting from the 24 million licensed vehicle registrations in Britain (Census September 1991) obviously exceeds 120 million. Home Office figures of the number of motorists prosecuted for defective tyres in the years 1985-89 inclusive total 340,666.

The present method of examination and inspection of tyre tread groove patterns of each individual tyre for evaluation and assessment of tread depth measurement is both labour intensive, time consuming and when applicable to road side inspection, human error could arise as a result of inclement weather and adverse lighting conditions.

Such a fine dividing line as .1 of a millimetre separating legal from illegal tread depth measurement could provide problems when examination and inspection conditions are less than ideal. The immense number of tyres available for examination together with the potential consequences that arise with worn tyres being subjected to severe braking, excessive speed and high speed cornering in wet weather conditions qualifies the invention to provide instant recognition that the tyre no longer conforms to the tyre tread depth legal limit set by the European Community Directive 89/459/EEC.

According to the present invention, there is provided a Pneumatic Tyre Tread Depth Indicator that is located and established at a defined and precise area during the manufacturing process of the pneumatic tyre.

gleans are provided for bright yellow colourisation, or an alternative bright colour, of this defined and precise area of the rubber/rubber composition to be known as the Pneumatic Tyre Tread Depth Indicator.

The depth of the coloured Pneumatic Tyre Tread Depth Indicator is calculated vertically from the defined datum point at the base of the tyre tread grooves to register a precise 1,59 millimetres for category A pneumatic tyres and .99 millimetre for category B pneumatic tyres throughout a continuous band comprising the central three-quarters of the breadth of tread around the tyre's circumference.

Adjacent at all points to the coloured Pneumatic Tyre Tread Depth Indicator, including the base of the tyre tread grooves, the rubber/rubber composition remains the conventional black colour.

This defined and precise area of the Pneumatic Tyre Tread Depth Indicator has been subjected, during the manufacturing process of the pneumatic tyre, to impregnation and saturation of a bright yellow colour compound, element, chemical agent or an alternative colour that has been evaluated by means of technical, optical or scientific analysis and examination to possess a greater attraction than bright yellow to the human eye.

Such impregnation and saturation is achieved using mechanical, electrical, electronic, hydraulic, pressurised, chemical or scientific processes.

Resultant tyre tread wear, by any means, of the normal black tread continues until a precise depth measurement of 1.59 millimetres for category A pneumatic tyres and .99 millimetre for category B pneumatic tyres is attained from the datum measuring point at any position around the tyre's circumference and across any portion of the central threequarters breadth of tread.

The Pneumatic Tyre Tread Depth Indicator then becomes operative, its bright yellow colour, or alternative bright colour, instantly showing the total area of tread that no longer conforms with the Ministry of Transport tyre tread regulations.

Periodic examination of the sides of the groove patterns within the central three-quarters breath of tread will reveal the amount of black rubber remaining before the Pneumatic Tyre Tread Depth Indicator becomes visible thus providing to the owner/driver an immediate assessment of the tyre's condition.

Locating the Pneumatic Tyre Tread Depth Indicator during the manufacturing process does not deem to cause variation in any measurements of the new pneumatic tyre.

A specific embodiment of the invention will now be described with reference to the accompanying drawing (not to scale) in which: Figure 1 shows, in part, sectional perspective of the said new pneumatic tyre with the location of the Pneumatic Tyre Tread Depth Indicator.

Vertical hatched lines denote the location of the precise and defined coloured area that is the Pneumatic Tyre Tread Depth Indicator.

Horizontal hatched lines denote the remainder of the rubber/rubber composition that remains the conventional black colour.

Referring to the drawing; the Pneumatic Tyre Tread Depth Indicator 14 is located during the tyre's manufacturing process comprising the central three-quarters breadth of tread 15, around the entire circumference of the tyre. The precise depth of 1.59 millimetres for category A pneumatic tyres and .99 millimetre for category B pneumatic tyres is measured from the datum point 16 at the base of the tread groove.

Claims

CLAINS.

1. A Pneumatic Tyre Tread Depth Indicator that is located and established at a defined and precise area during the manufacturing process of the pneumatic tyre.

Means are provided for bright yellow colourisation. or an alternative bright colour, of this defined and precise area of the rubber/rubber composition to be known as the Pneumatic Tyre Tread Depth Indicator.

The depth of the coloured Pneumatic Tyre Tread Depth Indicator is calculated vertically from the defined datum point at the base of the tyre tread grooves to register a precise 1.59 millimetres for category A pneumatic tyres and .99 millimetre for category B pneumatic tyres throughout a continuous band comprising the central three-quarters of the breadth of tread around the tyre's circumference.

l

2. A Pneumatic Tyre Tread Depth Indicator as claimed in Claim 1, wherein colourisation is attained by means of impregnation and saturation, during the manufacturing process, of a bright yellow colour compound, element, chemical agent or an alternative colour that has been evaluated by means of technical, optical or scientific analysis and examination to possess a greater attraction than bright yellow to the human eye.

3. A Pneumatic Tyre Tread Depth Indicator as claimed in any preceding claim, wherein such impregnation and saturation is achieved using mechanical, electrical, electronic, hydraulic, pressurised, chemical, or scientific processes.

4. A Pneumatic Tyre Tread Depth Indicator as claimed in any preceding claim, wherein means are provided during the tyre's manufacturing processes for its tread depth measuring datum point to be located at the base of the tyre tread groove.

5. A Pneumatic Tyre Tread Depth Indicator as claimed in any preceding claim, wherein means are provided during the tyre's manufacturing processes for its depth to be of a precise measurement of 1.59 millimetres for category A pneumatic tyres and .99 millimetre for category B pneumatic tyres.

6. A Pneumatic Tyre Tread Depth Indicator as claimed in any preceding claim, wherein means are provided during the tyre's manufacturing processes to have a precise width comprising the central three-quarters of the breadth of tread.

GLANS.

7. A Pneumatic Tyre Tread Depth Indicator as claimed in any preceding claim, wherein means are provided during the tyre's manufacturing processes that extends the Pneumatic Tyre Tread Depth Indicator around the circumference at the precise measured points appertaining to its datum point, claimed depth and claimed central three-quarters breath of tread.

8. A Pneumatic Tyre Tread Depth Indicator as claimed in any preceding claim, wherein means are provided during the tyre's manufacturing processes whereby adjacent at all points to the coloured Pneumatic Tyre Tread Depth Indicator, including the base of the tyre tread grooves, the rubber/rubber composition remains the conventional black colour.

9. A Pneumatic Tyre Tread Depth Indicator as claimed in any preceding claim, whereby its manufacture does not cause alteration to any dimensions of the new pneumatic tyre.

10. A Pneumatic Tyre Tread Depth Indicator as claimed in any preceding claim, wherein means are provided during the tyre's manufacturing processes whereby the Pneumatic Tyre Tread Depth Indicator will only become operative when, as a result of tyre tread wear by any means, the tyre tread depth measurement recorded at any position within any of the tyre pattern grooves across the central three-quarters breadth of tread has been reduced to 1.59 millimetres for category A pneumatic tyres and .99 millimetre for category B pneumatic tyres when measured from the the datum point at the base of the tyre tread groove.

11. A Pneumatic Tyre Tread Depth Indicator as claimed in any preceding claim, wherein means are provided during the tyre's manufacturing processes thus enabling instant visual assessment of the amount of legal tyre tread remaining prior to its elimination through tyre tread wear.

12. A Pneumatic Tyre Tread Depth Indicator as claimed in any preceding claim, wherein means are provided during the tyre's manufacturing processes such that when the Pneumatic Tyre Tread Depth Indicator becomes operative, visual recognition is attained that provides decisive evidence that the tyre no longer conforms with ministry of Transport tyre tread depth regulations.