Bandag Incorporated

Bandag Licensing Corporation

Donaldee Brewer

Edwin T Brodie

Ronald R Seiler

Michael J Dundon

Thomas J Niedergeses

The present invention involves a tire buffing apparatus. A rasping or buffing element is mounted in a manner which allows a compound radius to be formed in the shoulder of the tire casing without removing the rasp from the surface of the tire casing during the buffing operation. A tire casing rotating assembly includes a system for mounting the tire casing and rotating the casing. A pedestal is movable toward and away from the rotating tire casing. The pedestal is pivotable about the central axis of the pedestal and rotatable over a predetermined arc about a vertical axis spaced from the central axis of the pedestal. A rasp is mounted rearwardly and offset from the central axis of the pedestal.

Tire buffing apparatus

A bead seal ring for use in the retreading of radial tires by use of a bead sealing ring unit that provides positive mechanical pressure for sealing the curing envelope between the bead sealing ring unit and the bead area of the tire by a radial force. In its relaxed or initial condition, the bead sealing ring unit has a diameter smaller than the bead diameter of the tire. The bead sealing ring unit is placed into sealing position and then expanded by a locking device secured to a metal band which is part of the bead sealing ring unit.

Bead seal ring unit

This invention is directed to a differential control valve. The differential pressure is maintained by differing area surfaces on a piston assembly which will be balanced at a predetermined differential established at the manufacturing operation. There is a spring member operating on two valve balls which provides a delayed pressurization of the controlled chamber. The control valve has a ball valve at the exit port to control the low pressure side of the differential control valve assembly, providing a fail-safe system with no adjustments required after manufacture if there is a pressure increase downstream.

Differential pressure control valve

The present invention covers the method and apparatus to retread tire casings using a precured tread system where an envelope or flexible fluid tight member is used to cover a retread tire casing assembly and then placed in an autoclave where the autoclave is pressurized and a reduced differential pressure is provided between the envelope member and the precured tread. This invention includes the automatic pressurizing of the system and the monitoring of the system during operation as a total system and/or for individual curing stations.

Tire retreading system with envelope pressure

An improved method and apparatus is shown for simultaneously retreading all of the tires in a stack of rubber tires that have been placed in an autoclave or the like. Each of the tires is covered respectively with a precured tread and enclosing envelope having a U-shaped cross section that surrounds the periphery of the tire to be retreaded, the inner edges of the respective envelopes being pressed to seal against the rims or shoulders of the tires. Proper sealing of the edges of the U-shaped envelopes against the sides of the tires is effected by compressing the stack against a back-up means adjustably supported on and locked in position on a post that extends centrally through the stack. The improved means for producing compression in the tire stack includes an inflatable tire means that surrounds the post to press the stack against the back-up means. The apparatus here shown is particularly adapted to a procedure for first pressurizing the stack and pulling a vacuum on the space inside each envelope prior to placing the stack in the autoclave and then placing the stack in the autoclave and inflating the pressure tire to maintain the seal between the tires and the envelopes. The curing process is then completed in the autoclave for applying the precured tread strips to the tires to effect the recapping of the tires.

Retreading stacked tires using inflatable pressure member

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 sharpening device for the rotatable cutting rasp of a tire buffing machine comprises a cylindrical rotatable sharpening stone carried at the free end of an arm which is pivoted to the frame of the machine to allow the operator to bring the stone into contact with the rotating rasps. Engagement of the edge of the rasp with the periphery of the stone causes the stone to rotate at lower speed than the rasp due to an adjustable spring-biased brake acting on the stone. An adjustable stop arrangement prevents over-sharpening.

Growing community of inventors

Muscatine, IA, United States of America

Donaldee Brewer