Method and system for retreading tires utilizing RF energy

A system for vulcanizing an uncured gum layer disposed between a vehicle tire carcass and a pre-cured tire tread comprising:

• an annular air bladder for being received within the tire carcass,
• a hub housing for being received within the center opening of the tire carcass,
• a chamber capable of withstanding high pressures and dimensioned to receive the vehicle tire carcass,
• a shaft rotatably and horizontally disposed in said chamber for receiving said hub housing,
• means extending through the wall of said chamber for rotating said shaft,
• means for pressurizing the interior of said chamber,
• an antenna extending from said chamber to a position adjacent the tire tread,
• a source of RF energy located outside said chamber,
• means connecting said RF source through the wall of said chamber to said antenna such that RF energy is directed through the tire tread to heat the gum layer to an extent sufficient to vulcanize the tire tread to the tire carcass, and
• means associated with the tire carcass for providing a path to circuit ground for said RF energy generated from said antenna.

A system for vulcanizing an uncured gum layer disposed between a vehicle tire carcass and a pre-cured tire tread comprising:

• a chamber capable of withstanding high pressures and including a pivotal side door,
• an axle centrally located in said chamber and mounted for horizontal rotation therein,
• a drive shaft extending through the side wall of said chamber and spaced from said axle,
• means exterior of said chamber for rotating said drive shaft,
• means within said chamber for transferring rotation of said drive shaft to said axle,
• a hub assembly adapted to be secured to the interior of the vehicle tire carcass and including structure for being affixed to the end of said axle, such that the tire carcass is vertically oriented,
• means for pressurizing the interior of said chamber,
• an antenna disposed within said chamber from the top of said chamber and including means for selectively positioning said antenna adjacent the tire tread,
• a source of RF energy located exterior of said chamber,
• means for feeding said RF energy from said source through the side walls of said chamber to said antenna, wherein RF energy is applied from said antenna through the tire tread to heat the gum layer sufficiently to vulcanize the tire tread to the tire carcass, and
• means associated with said antenna for providing a path to circuit ground for the RF energy generated from said antenna.

An antenna for applying RF energy to a rotating tire within a pressurized chamber comprising:

• an antenna element having a configuration to generally conform with a portion of the outer periphery of the rotating tire,
• wheel means attached to the said antenna for abutting with the rotating tire in order to maintain said antenna a predetermined distance from the outer periphery of the rotating tire,
• means connected with said antenna and extending through the walls of the chamber for applying RF energy to said antenna,
• an insulating member pivotally connected to said antenna on the opposite side of said antenna from the rotating tire, and
• a support member pivotally attached to said insulating member and disposed to support said antenna within the chamber.

The method of retreading tires comprising:

• removing an old tread from a tire casing,
• applying a length of uncured cushion gum about the outer periphery of the tire casing,
• applying a length of a pre-cured tread about the outer periphery of the cushion gum,
• positioning an RF grounding member about the inner periphery of the tire casing,
• positioning an inner tube within the tire casing,
• mounting the tire casing on a hub,
• mounting the hub on an axle within a pressure chamber,
• pressurizing the pressure chamber,
• rotating the axle to rotate the tire casing within the pressure chamber, and
• applying RF energy to an antenna fixedly disposed adjacent the rotating tire casing, said RF energy having a magnitude sufficient to vulcanize the cushion gum in order to vulcanize the pre-cured tire tread to the tire casing.

A system for retreading tires comprising:

• means for supporting at least one tire having an uncured gum layer and a pre-cured tread exposed about the outer periphery thereof,
• means for surrounding the tire, gum layer and pre-cured tread for exerting continuous pressure against the pre-cured tread to maintain it in place about the outer periphery of the tire,
• an antenna disposed adjacent the outer periphery of the pre-cured tread,
• means for rotating said antenna and the tire relative to one another such that said antenna cyclically scans the periphery of the pre-cured tread,
• means for applying RF energy to said antenna such that the uncured gum layer around the tire is heated sufficiently to become vulcanized to affix the pre-cured tread to the tire, and
• means associated with the tire for providing an RF energy path to circuit ground.

A method of retreading tires comprising:

• removing an old tread from a tire casing,
• applying a length of uncured cushion gum about the outer periphery of the tire casing,
• applying a length of a pre-cured tread about the outer periphery of the cushion gum,
• positioning an inner tube within the tire casing,
• mounting the tire casing on a hub,
• mounting the hub such that the periphery of the pre-cured tread is adjacent an RF antenna,
• rotating the pre-cured tread and the RF antenna relative to one another while maintaining continuous pressure against the pre-cured tread to the tire casing,
• applying RF energy to said antenna of a magnitude sufficient to vulcanize the cushion gum in order to vulcanize the pre-cured tire tread to the tire casing, and
• providing an RF energy path from the tire casing to circuit ground.