Bridgestone Tire Company Limited

Isao Miyoshi

Masaru Abe

Toshiro Tezuka

Toshio Yoshimoto

Osamu Inoue

Koji Chiba

A pneumatic tire for off-road vehicles, comprising a carcass body containing organic fiber cords and a breaker composed of at least one rubberized layer each containing reinforcing elements embedded therein and having an overall cut resistant property for all types of cuts together with an excellent separation resistant property and high abrasion resistant property is disclosed. The reinforcing element is composed of a bundle formed by merely assembling helically formed filaments together without twisting. The reinforcing element is formed of a material having a tensile strength of at least 140 Kg/mm.sup.2 and an elongation at breaking strength which is 0.15 to 1.7 times that of the organic fiber cord of the carcass body.

Pneumatic tires for off-road vehicles

A pneumatic tire for off-road vehicles comprising a reinforcing element composed of helically formed filaments and having an excellent side-cut resistant property is disclosed. The tire is provided at its side portion with a side portion reinforcing layer composed of at least one rubberized layer containing a reinforcing element embedded therein and formed of a helically formed filament or a bundle of at least two helically formed filaments assembled together without twisting at random. The filament is formed of a material having a tensile breaking strength of at least 140 kg/mm.sup.2. The reinforcing filament has an elongation at tensile breaking strength which is 0.15 to 1.7 times that of organic cord of a ply of a carcass body. The rubberized layer containing said reinforcing element embedded therein as a whole is extensible.

Pneumatic tire for off-road vehicles

A rubber reinforcing member and a method of manufacturing the same are disclosed. The rubber reinforcing member is composed of rubber and a number of filamentous elements embedded therein. The filamentous element is formed of a metal or a material having a strength similar to that of the metal and has a helix on at least one end portion thereof.

Rubber reinforcing member and a method of manufacturing the same

A pneumatic tire for off-road vehicles comprising a multi-layered carcass and a breaker superimposed about the carcass. The carcass is composed of rubberized ply layers each containing cords formed of organic fiber and inclined at an angle of 23.degree. to 45.degree. with respect to the equatorial line of the tire. The cords of approximately one-half of the carcass plies extend in an opposite direction to the cords associated with the remaining plies. The breaker is composed of at least one rubberized layer each containing reinforcing elements formed of a plurality of filaments whose material having a tensile strength of at least 140 Kg/mm.sup.2, the reinforcing element being inclined at an angle which is not larger than a selected angle of the carcass cord by at least 5.degree. and not smaller than the selected angle of the carcass cord by at least 15.degree.. At least one rubberized layer of the breaker disposed near the tread is extended over a width of 40 to 60% of the tread width.

Pneumatic tires suitable for off-road vehicles

A pneumatic tire for off-road vehicles, which is highly durable under heavy load conditions is disclosed. The tire makes use as its breaker of a reinforcing element formed of material having a high cut resistant property such as steel or glass. The least possible number of those plies of a plurality of rubberized ply layers of a carcass body which extend from a crown portion of the tire through both side portions up to both bead members and which can substantially withstand internal pressure applied to the tire and external force subjected thereto is determined on the basis of a fundamental safety factor .xi. and which lies within a range of a correction safety factor .eta. which depends on the use and type of the tire and the depth of tread groove.

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Kodaira, Japan

Isao Miyoshi