Method for retreading tires

Claim 2

A process for retreading a tire as claimed in claim 1 wherein the pressure maintained in said inflatable means is at least 20 pounds higher than the pressure maiNtained in the sealed chamber.

Claim 3

A process for retreading a tire as claimed in claim 1 wherein said tire assembly is mounted on a rim prior to its insertion in said multipart shell.

Claim 4

A process for retreading a tire as claimed in claim 1 wherein said fluid comprises steam having a temperature of 212*- 300*.

Claim 5

A process for retreading a tire with a precured, premolded tire tread comprising: a. preparing a tire casing for retreading by roughing the exterior tread receiving portion; b. applying a precured tread strip to the exterior of the tire casing with an uncured layer of rubber therebetween to form a tire assembly prepared for retreading, c. covering said tire assembly with a thin, flexible envelope which covers said tread strip and extends from sidewall to sidewall around the outer perimeter of said assembly; d. inserting an inflatable means into the interior of said casing, e. inserting said tire assembly and said envelope into a multipart rigid shell having a generally annular shape and a U-shaped cross-section, said shell defining a sealed chamber above the tread portion of the assembly, f. sealing said mold to define a fluid-tight chamber between said mold and the exterior of said envelope, said sealing also including the pressurization of said inflatable means to laterally distend the sidewalls of the casing into contact with the sealing means mounted on the inner walls of the shell adjacent the casing sidewalls, g. pressurizing both the fluid-tight chamber and the tire assembly to provide positive fluid pressures therein with a higher fluid pressure in the tire assembly; h. simultaneously exhausting any air trapped between said flexible envelope and said tire assembly with venting means located between said envelope and said casing, i. heating said tire assembly within said mold to bond said strip to said casing.

Claim 6

A process as claimed in claim 6 wherein said tire assembly and said envelope are inserted into a standard tire retreading mold, said mold having been previously lined with a mold liner to seal the interior of the mold.

Claim 7

A process for retreading a tire as claimed in claim 6 wherein the pressure maintained in said inflatable means is at least 20 pounds higher than the pressure maintained in the sealed chamber.

Claim 8

A process for retreading a tire as claimed in claim 6 wherein said tire assembly is mounted on a rim prior to its insertion in said multi-part shell.

Claim 9

A process for retreading a tire as claimed in claim 1 wherein said assembly is heated by a fluid having a temperature of at least 150*.

Claim 10

A process for retreading a tire as claimed in claim 10 wherein said fluid is steam having a temperature of 212*- 300*.

Claim 11

A process for retreading a tire as claimed in claim 1 wherein said sealing means is inserted into the sidewalls of said shell before said shell is sealed.

Claim 12

A process for retreading a tire as claimed in claim 12 wherein said shell is adjusted to various sized tires by inserting differentially sized sealing means to match the tire to the shell.

Claim 13

A process for retreading tires as claimed in claim 6 which further comprises a. inserting said enveloped tire assembly into a retreading assembly having a flat circular base portion, upwardly extending securing means, and an upwardly extending thin annular ring that circumferentially surrounds the tire assembly, b. covering said tire assembly and said annular ring with a cover means and c. securing said cover means to said base by said upwardly extending securing means to define a sealed chamber therein.