Title of Invention

A TYRE

Abstract A tyre P, comprising a radial carcass reinforcement (1) surrounded by a crown reinforcement (3) formed of at least one working reinforcement comprising two plies (31, 32) of inextensible metallic reinforcement elements, which are parallel to each other within each ply and are crossed from one ply (31) to the next (32), forming with the circumferential direction angles &#940;1 and &#940;2 of between 10° and 45°, said working plies having axial widths L1 and L2, and of at least one ply (33), referred to as a protective ply, of axial width L3 such that L3 < L2 < L1, said reinforcement elements of the protective ply (33) being inclined in the same direction as the reinforcement elements of the radially adjacent working ply (32), characterised in that arranged on either side of the equatorial plane XX', in the axial extension of the protective ply (33), is an additional ply (34) of inextensible metallic reinforcement elements of the same direction as that of the reinforcement elements of the radially outer working ply (32) and forming with the circumferential direction an angle &#940;4 greater in absolute value than the angle &#940;2 of the elements of said working ply (32) by at least -5°, the axial width LA of each said additional ply (34) being such that its axially outer end is distant from the equatorial plane XX' by an amount greater than half the width of the least wide and radially outer working ply (32), and such that it does not cover the axial end of the widest and radially inner working ply (31), said axially outer end of said additional ply (34) being located at a distance from the equatorial plane of the tyre of between 42.5 and 47.5% of the axial width L1 of the widest working ply (31) which is radially to the outside.
Full Text FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See Section 10; rate 13]






SOCIETE DE TECHNOLOGIE MICHELIN, of 23, rue Breschet, F-63000 Clermont-Ferrand, France and MICHELIN RECHERCHE ET TECHNIQUE S.A., of Route Louis Braille, lOet 12, CH-1763, Granges Paccot, Switzerland,
The following specification particularly describes the invention and the manner in which it is to be performed:

The present invention relates to a tyre.
The present invention relates to a tyre having a radial carcass reinforcement, which, is intended to be fitted on heavy vehicles such as lorries, buses, tractors', traders etc., and relates more particularly to the crown-reinforcement of such a tyre.
Generally, the radial carcass reinforcement of the tyre in question, which is formed of inextensible reinforcement elements made of metal or of aromatic polyamide, is surmounted radially by a crown reinforcement comprising a plurality of crown plies, in particular a triangulation ply formed of metallic elements which are oriented relative to the circumferential direction by a large angle of between 45° and -90°, said triangulation ply in turn being surmounted by two working plies formed of inextensible metallic reinforcement elements which are parallel to each other within each ply and are crossed from one pfy to the next, forming angles of between 10° and 45° with the circumferential direction. Said working plies, which form the working reinforcement, are generally covered by at least one so-called protective ply, formed, in the majority of cases, of extensible metallic reinforcement elements, which are also referred to as elastic elements.
In the case of a tyre for "heavy vehicles", a single protective ply is present and its protective elements are generally oriented in the same direction and at the same ■ angle in absolute value as those of the reinforcement elements of the radially outermost working ply, and generally less wide than the least wide, radially outermost working ply. Such crown reinforcements do not have sufficient endurance, in that, when the tyres are running under high drift stresses,, numerous breaks in the rubber appear and spread between the edges of the two working crown piies.
French Patent 1 435 804 of the Applicant, in order to avoid separation of the ends of the crown reinforcement when the tyre is subject to high-speed travel, teaches arranging on either side of said reinforcement a narrow ply of cables forming an angle which may be between 40° and 70° with the cables of the carcass reinforcement. Said ply may be placed partially either above the crown reinforcement,

or between the two working plies, or between the crown reinforcement and the carcass reinforcement. Any material desired may form the cables.
Japanese Application JP 63/125 406, in order to improve the uniformity, advocates the use of small reinforcement plies for the edges of the working reinforcement, said plies being formed of reinforcement elements made of inorganic fibre, such as carbon fibre or glass fibre, which are oriented parallel to the elements of the radially outer working ply.
US Patent 5 435 369, in order to guard against separations at the ends of the crown plies, teaches covering the ends of the two widest plies with additional small plies of reinforcement elements of material selected from among steel, aromatic polyamide, nylon, etc, and oriented relative to the circumferential direction by an angle which may be between 0° and 55°.
The progress made in terms of length of life (number of kilometres travelled) on wear of the "heavy-vehicle" tyres, and also the possibility of easy, economical later recapping, requires a crown reinforcement, the resistance to separation between the edges of working plies of which is improved.
Thus the tyre according to the invention comprises a radial carcass reinforcement radially surmounted by a crown reinforcement formed of at least one working reinforcement formed of two plies of inextensible metallic reinforcement elements, which are parallel to each other within each [ply] and are crossed from one ply to the next, forming angles a1 and a2 of between 10° and 45° with the circumferential direction, said working plies having axial widths L-1 and L-2, and of at least one ply, referred to as a protective ply, of axial width L3 such that L3
ply and forming with the circumferential direction an angleά4 greater in absolute value than the angle ά2 of the elements of said working ply by at least 5°, the axial width LA of each said additional ply being such that its axially outer end is distant from the equatorial plane by an amount greater than half the width of the least wide and radially outer working ply, and such that it does not cover the axial end of the widest and radially inner working ply, said axially outer end of said additional ply being located at a distance from the equatorial plane of the tyre of between 42.5 and 47.5% of the axial width L-1 of the widest working ply which is radially to the outside.
As is known per se, the addition between the working reinforcement and carcass reinforcement of what is called a triangulation ply may be advantageous, said ply being formed of inextensible metallic elements inclined greatly relative to the circumferential direction at an angle which may be between 45° and 90°, and having an axial width L0 which is less than the width L1'of the first working ply.
Preferably the difference ά4 - ά2 is not greater than 20°. If said difference is less than 5°, the resistance to separation between working plies is not improved; if the difference is greater than 20°, it is possible to obtain the opposite effect to that desired, that is to say adversely to affect the separation between edges of the working crown plies.-j
The characteristics of the invention will be better understood with reference to the description of an embodiment illustrated by the appended drawing, comprising a single figure 1.
The tyre P of dimension 385/65 R 22.5 X comprises a radial carcass reinforcement composed of a single ply 1 of inextensible metal cables, that is to say, cables which have an elongation of at most 0.2% under a tensiie force equal to 10% of the breaking load. Said carcass reinforcement is anchored within each bead to a bead wire 2 to form an upturn 10. It is surmounted, radially to the outside, by a crown reinforcement 3 comprising radially from the inside to the outside:

- a first crown ply 30 referred to as a triangulation ply, formed of inextensible metal cables made of steel, which are oriented at an angle ά0. equal in the case described to 50°,
- surmounting said ply 30, a first working crown ply 31, formed of inextensible metal cables made of steel, forming with the circumferential direction an angle ά-1 of
18°, the cables of the trianguiation ply 30 and of the first working ply being of the same direction,
- then a second working crown ply 32 formed of metal cables identical to
those of the first ply 31, and forming with the circumferential direction an angle ά2
opposed to the angle ά-1 and, in the case illustrated, equal in absolute value to said
angle ά-1 of 18°, (but possibly being different from said angle ά-1),
- a last, axially continuous, ply 33 of so-called elastic metal cables made of steel, which are oriented relative to the circumferential direction by an angle ά3 of the same direction as the angle ά,2, and equal in absolute value to said angle ά2, this last piy being a so-called protective ply, the so-called elastic metal cables being cables having a relative elongation of at least 4% at break;
- on either side of the equatorial plane XX' and in the axial extension of the ply 33, an additional ply 34 of inextensible metal cables made of steel, which are parallel to each other within each ply and form with the circumferential direction an angle ά4 of the same direction as the angles ά3 andά2 formed by the cables respectively of the plies 32 and 33, but greater than said angles by an amount equal to 8°, since it is equal to 26°.
The axial width L-1 of the first working ply 31 is equal to 0.78 times the maximum axial width S0 of the centre section of the carcass reinforcement (1), namely 280 mm, which, for a tyre of conventional shape, is less than the width of the tread, which is equal, in the case in question, to 286 mm. The axial width L2 of the second working ply 32 is less than the width L-1, since it is equal to 212 mm. The axial width L() of the

triangulation ply 30 is equal to 270 mm, which represents 0.75 S0-The width L3 of the protective ply 33 is less than the width L2 of the least wide and radially adjacent working ply 32, and is equal to 120 mm. As for the axial width of each additional ply 34, it is equal to 70 mm; said ply 34 is approximately centred on the end of the least wide, radially outer working ply 32.
The tyres thus described were subjected to endurance testing using running on vehicles and under high drift stresses. Whereas the control tyres, which had a protective ply less wide than the second working ply and formed of reinforcement elements forming with the circumferential direction the same angle as the elements of said working ply, covered on average 6225 km, the tyres of the invention travelled for 8660 km, which is a gain of about 39%, without said tyres being adversely affected in terms of separations between the two working plies.

We Claim:
1. A tyre P, comprising a radial carcass reinforcement (1) surrounded by
a crown reinforcement (3) formed of at least one working reinforcement
comprising two plies (31, 32) of inextensible metallic reinforcement
elements, which are parallel to each other within each ply and are crossed
from one ply (31) to the next (32), forming with the circumferential direction
angles ά1 and ά2 of between 10° and 45°, said working plies having axial
widths L1 and L2, and of at least one ply (33), referred to as a protective ply,
of axial width L3 such that L3 protective ply (33) being inclined in the same direction as the reinforcement
elements of the radially adjacent working ply (32), characterised in that
arranged on either side of the equatorial plane XX', in the axial extension of
the protective ply (33), is an additional ply (34) of inextensible metallic
reinforcement elements of the same direction as that of the reinforcement
elements of the radially outer working ply (32) and forming with the
circumferential direction an angle ά4 greater in absolute value than the
angle ά2 of the elements of said working ply (32) by at least -5°, the axial
width LA of each said additional ply (34) being such that its axially outer end
is distant from the equatorial plane XX' by an amount greater than half the
width of the least wide and radially outer working ply (32), and such that it
does not cover the axial end of the widest and radially inner working ply
(31), said axially outer end of said additional ply (34) being located at a
distance from the equatorial plane of the tyre of between 42.5 and 47.5% of
the axial width L1 of the widest working ply (31) which is radially to the
outside.

2. A tyre as claimed in Claim " 1, wherein it comprises between the working reinforcement (3) and the carcass reinforcement (1) a triangulation ply (30), formed of inextensible metallic elements inclined greatly relative to the circumferential direction with an angle ά0 of between 45° and 90°, and having an axial width Lo which is less than the width L1 of the first working ply (31).
3. A tyre as claimed in Claim 1, wherein the difference Ά4 - ά2 between the angle of the reinforcement elements of the additional ply (34) and the angle of the reinforcement elements of the working ply (32) which is least wide and radially to the outside is not greater than 20°.
Dated this the 23rd. day of April, 2002



Documents:

abstract1.jpg

in-pct-2002-00526-mum-cancelled pages(19-10-2005).pdf

in-pct-2002-00526-mum-claims(granted)-(19-10-2005).doc

in-pct-2002-00526-mum-claims(granted)-(19-10-2005).pdf

in-pct-2002-00526-mum-correspondence(19-10-2005).pdf

IN-PCT-2002-00526-MUM-CORRESPONDENCE(21-9-2012).pdf

in-pct-2002-00526-mum-correspondence(ipo)-(6-9-2007).pdf

in-pct-2002-00526-mum-drawing(19-10-2005).pdf

in-pct-2002-00526-mum-form 13(16-8-2007).pdf

IN-PCT-2002-00526-MUM-FORM 16(9-8-2012).pdf

in-pct-2002-00526-mum-form 19(22-9-2004).pdf

in-pct-2002-00526-mum-form 1a(16-8-2007).pdf

in-pct-2002-00526-mum-form 1a(19-10-2005).pdf

in-pct-2002-00526-mum-form 1a(23-4-2002).pdf

in-pct-2002-00526-mum-form 2(granted)-(19-10-2005).doc

in-pct-2002-00526-mum-form 2(granted)-(19-10-2005).pdf

in-pct-2002-00526-mum-form 3(19-10-2005).pdf

in-pct-2002-00526-mum-form 3(23-4-2002).pdf

in-pct-2002-00526-mum-form 5(23-4-2002).pdf

in-pct-2002-00526-mum-form-pct-ipea-409(23-4-2002).pdf

in-pct-2002-00526-mum-form-pct-isa-210(23-4-2002).pdf

in-pct-2002-00526-mum-petition under rule 137(19-10-2005).pdf

in-pct-2002-00526-mum-petition under rule 138(19-10-2005).pdf

in-pct-2002-00526-mum-power of authority(5-4-2002).pdf


Patent Number 209748
Indian Patent Application Number IN/PCT/2002/00526/MUM
PG Journal Number 41/2007
Publication Date 12-Oct-2007
Grant Date 06-Sep-2007
Date of Filing 23-Apr-2002
Name of Patentee SOCIETE DE TECHNOLOGIE MICHELIN
Applicant Address 23, RUE BRESCHET, F-6300 CLERMONT- FERRAND, FRANCE.
Inventors:
# Inventor's Name Inventor's Address
1 LUCIEN BONDU CHEMIN DE LA SOURCE, F-63800 LA ROCHE NOIRE, FRANCE.
PCT International Classification Number B60C 9/20
PCT International Application Number PCT/EP00/09864
PCT International Filing date 2000-10-09
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 99/14093 1999-11-08 France