The specification discloses an apparatus and method for adapting a standard tire retreading mold to use the newer continuous precured and premolded tire tread in retreading tires. The apparatus and method also make it possible to adapt a single size standard tire retreading mold to retread a number of different size tires by use of a mold liner and a plurality of variably sized gasket sealing means.
This is a division of application Ser. No. 883,161, filed Dec. 8, 1969, now abandoned. This divisional application is copending with application Ser. No. 182,603 and application Ser. No. 182,814, both of which are divisional applications of the parent U.S. application Ser. No. 883,161, now abandoned. This application is also copending with application Ser. No. 247,488, a continuation of application Ser. No. 883,161.
In bonding a prevulcanized tread strip to a tire casing with a low-temperature-vulcanizable bonding medium temporary support elements in the form of elastic rings are inserted in the circumferential tread grooves during pressing of the tread strip against the tire casing for the purposes of achieving uniform pressure over the whole tread strip and preventing distortion or movement of portions of the tread strip and/or bonding medium during the bonding operation.
A tread for the recapping of tires is provided with a roughened internal surface simultaneously with the shaping of profile on its external surface in a vulcanizing form. The internal surface can be roughened by placing against the body of raw rubber in the form of a latticework, a plate with regularly or irregularly distributed projections or a composite deforming structure. The internal surface of the prefabricated tread can be sealed from the atmosphere by a foil which is applied to the internal surface directly in the form or subsequent to removal of tread from the form.
Method and apparatus for retreading tires with electrical resistance wires for heating the rubber to vulcanize same including the attachment of wires between thin base strips with a rubber cushion disposed beneath a new tread element to be attached to the carcass. The base strips are configured to limit heat flow from the wires thereto. New tread is held in place by a split restraining hoop having side flanges directed to engage the base strips and electrical energization of the wires is made through connectors to opposite sides of the hoop. After vulcanizing by electrically generated heat the base strips are stripped from the then embedded wires. A process of manufacture comprising heating wires extending transversely between thin electrically conducting base strips with a rubber cushion covering the wires and limited attachment to the base strips with the base strips being separable from substantially all of the wire length after use of the product in a vulcanizing process.
A mold-type apparatus used in retreading a tire casing with a precured tread. The apparatus is composed of two halves or sections which carry rubber curing bags. The bags are inflated with steam and used to press the precured tread firmly against the tire casing while heating and curing the gum rubber and adhesive normally used between the precured tread and the tire casing.
A method and apparatus for producing both wing-type and wingless tire treads from a single mold. The mold includes a main portion, a pair of first inserts which are selectively attachable to the main portion. The pair of first inserts is capable of molding wingless treads. A pair of second inserts can be selectively secured to the main portion in place of the first pair of inserts to mold wing-type treads. The method for converting a wingless tire tread mold to a wing-type tire tread mold includes the steps of removing the pair of first inserts from the main portion of the mold and securing the pair of second inserts to the main portion of the mold with the securing apparatus.
