Bridgestone Tire Company Limited

Iwao Arimura

Akio Sato

Yasuo Suzuki

Hironori Hirano

Shigeo Makino

Hiroyoshi Takigawa

Akira Matsuda

Shinichiro Ohkuni

Makoto Tanaka

A pneumatic tire for a heavy duty vehicle including a tread surface divided along circumferential directions by at least two tread zigzag grooves to form a plurality of circumferential zigzag ribs comprises stress releasing apertures formed at least in zones of the circumferential ribs which are within distances approximately 30% of widths of the circumferential ribs from the side of the ribs to mitigate stress concentrations in corners of the ribs extending in the tread grooves by reducing rigidities of the corners for preventing railway wear which would otherwise occur in the tire of this kind.

Pneumatic tire for a heavy duty vehicle

A pneumatic radial tire so constructed as to reduce a breaker interlayer shearing strain without adding any particular supplemental reinforcing layer is disclosed. The radial tire has an initial sectional shape which satisfies the following conditions.

Pneumatic radial tires

A device for making a pneumatic tire including an outer mold and a core for making tread rubber having a high lug or deep tread pattern and an inflatable bladder for use in joining the tread rubber to the tread portion of a green case when the green case is shaped and vulcanized.

Device for making pneumatic tires

A pneumatic radial type tire having an improved durability in bead section comprises at least one carcass ply composed of metal cords in a substantially radial arrangement, at least one chafer composed of rubberized metal cords, a carcass reinforcing member secured to the surface of the carcass ply and composed of at least two rubberized cord fabrics whose cords are crossed with each other at an angle larger than 60.degree. with respect to the cord direction of the carcass ply, and a rubber stiffener composed of a composite rubber stock having a hardness which is made smaller at the upper part than at the lower part thereof.

Pneumatic radial type tire having an improved durability in bead section

A pneumatic tired wheel having excellent highspeed performance after puncture comprises a tubeless tire, a bead stopper and a rim. The tubeless tire comprises a pair of elastic reinforcements having a Shore A hardness of at least 47, the bead stopper comprises an independent air-tight chamber and a crown portion with at least one inextensible reinforcing layer. The crown portion has an outer diameter determined in connection with the outer diameters of the flange of the rim and the tread portion of the tire.

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Kodaira, Japan

Iwao Arimura