Dunlop Gmbh

Anthony Gerald Goodfellow

Eric Holroyd

James N McGlashen

Maurice Rand

In the moulding of the tread portion of a pneumatic tire the radially inner surface of the mould cavity is defined by the radially outer surface of an annular former of elastomeric material. The former is contracted, a breaker assembly is built onto it and it is allowed to expand to stress the breaker. In the mould the former is further expanded and is held in compression between mould parts and the breaker to withstand moulding pressure. The former may have inflatable pockets to throw the breaker edges into contact with tire sidewall reinforcements.

Tire tread molding apparatus

In molding the tread portion of a pneumatic tire to have a breaker structure incorporated therein the breaker is built in an annular mold cavity to have a radially outermost 90.degree. ply consisting of parallel cords extending axially of the cavity, and uncured rubber is introduced into the cavity through an annular gate surrounding the cavity so as to spread axially of the cavity. As the introduced uncured rubber does not move circumferentially of the cavity it has no tendency to displace the breaker cords.

Tire manufacture

A pneumatic tire is moulded using a mould core of cured rubber the radial sectional shape of which is the same as the internal radial sectional configuration of the finished tire. The opposite sides of the core are supported by fitting plates while a tread portion of tire is moulded onto the exposed outer periphery of the core. Thereafter the side plates are removed in turn and replaced by sidewall mould halves enabling sidewalls to be moulded against the core in contact with the tread portion.

Manufacture of pneumatic tires

A method is provided whereby the three components (sidewalls and tread) of a pneumatic tire are moulded in a single press operation using two transfer units charged with uncured rubber which are located in the press so as to discharge to the mould cavities when the press is closed, after which the press is opened to allow removal of the transfer units, (the moulded components remaining in the press) and then reclosed to assemble the components together. Each transfer unit comprises at least one reservoir for uncured rubber defined between parts of the unit which are relatively movable under the action of the press to transfer the rubber from the reservoir(s) to associated mould cavities.

Manufacture of moulded articles

A method for making tires. The tire is first formed in two or more parts from uncured rubber, in mould cavities provided with locking sprues to retain the moulded tire part in a desired section of the moulding. The mould is pressurized, at least when moulding the tire sidewalls, then opened and the moulded uncured tire parts carried in parts of the mould are brought together and joined under heat and pressure.

Pneumatic tire manufacture

In moulding the tread portion of a pneumatic tire to have a breaker structure incorporated therein the breaker is built in an annular mould cavity to have a radially outermost 90.degree. ply consisting of parallel cords extending axially of the cavity, and uncured rubber is introduced into the cavity through an annular gate surrounding the cavity so as to spread axially of the cavity. As the introduced uncured rubber does not move circumferentially of the cavity it has no tendency to displace the breaker cords.

Method of making a tire by first molding a tread and then molding

A moulding apparatus including a pair of mould cavities with locking spue grooves, means to form moulded rubber article parts in the cavities, means to prework the rubber without substantial curing before it is formed, means to pressurize the mould with gas and means to bring the mould cavities together to join the article parts. The arrangement for pressurizing the mould includes a retractable casing which is movable between a position in which the mould cavities are enclosed to permit their pressurization and a position in which the cavities are accessible outside the casing.

Moulding apparatus

An apparatus is provided whereby the three components (sidewalls and tread) of a pneumatic tire are moulded in a single press operation using two transfer units charged with uncured rubber which are located in the press so as to discharge to the mould cavities when the press is closed, after which the press is opened to allow removal of the transfer units, (the moulded components remaining in the press) and then reclosed to assemble the components together. Each transfer unit comprises at least one reservoir for uncured rubber defined between parts of the unit which are relatively movable under the action of the press to transfer the rubber from the reservoir(s) to associated mould cavities.

A method of manufacturing tire inner tubes in which the tube is moulded in two annular parts from worked uncured rubber, and the parts are joined but before curing of the rubber is completed the tube is stretched to a larger internal diameter and inflated into a mould with the larger internal diameter.

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Maghull, near Liverpool, United Kingdom

Anthony Gerald Goodfellow