Bandag Incorporated

Bandag Incorporation

Edwin T Brodie

Donaldee Brewer

Ronald Seiler

Ioan A Burche

Tire treads are designed to be receptive to the technique of cutting parallel slits therein for the purpose of improving traction and wear life. In order to obtain the advantages of slitting while avoiding cracking and breaking off of tread elements during use, the slit angle, general guides for the tire size and type and slit depth should be chosen within prescribed limits, and additional voids such as shoulder grooves, cross grooves and cross molded voids should be parallel to the slits. Tie bars integral at their ends with tread elements extend across the tread grooves to provide lateral support for the tread elements.

Slitted tire tread

Tire casings are retreaded with precured tread strips in a heated pressure vessel provided with pressure connections which effect simultaneous inflation of the tires and pressurization of the vessel while maintaining tire pressure above vessel pressure. Subsequently a pressure relief system permits the tires to exhaust faster than the vessel. Each tire is prepared for retreading by applying a bonding medium between the tire periphery and the retread strip and wrapping the resulting assembly with a fluid impervious flexible cover. Tread stabilization rings, wick material and non-stick polymer film may be inserted between the tread strip and the cover.

Pressure vessel system for retreading tires

Tire retreading method using pressure vessel

Tire retreading system

A strip of rubber base bonding material for use in cold bonding a prevulcanized tread strip to a tire contains both a low-temperature vulcanizing agent and accelerators. The bonding material is compounded by a special technique which stabilizes the vulcanizing agent and the accelerator thereby avoiding prevulcanization during storage. In use the bonding material is interposed between the tread strip and the tire, and the assembly is heated to less than about 300.degree. F under pressure to effect vulcanizing of the bonding material.

Material and methods for bonding treads to tires

A strip of rubber base bonding material for use in cold bonding a prevulcanized tread strip to a tire contains both a low-temperature vulcanizing agent and accelerators. The bonding material is compounded by a special technique which stabilizes the vulcanizing agent and the accelerator thereby avoiding prevulcanization during storage. In use the bonding material is interposed between the tread strip and the tire, and the assembly is heated to less than about 300.degree.F under pressure to effect vulcanizing of the bonding material.

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.

Growing community of inventors

Muscatine, IA, United States of America

Edwin T Brodie