TH21439B - Truck tires with improved pre-cured tread for truck tires. And assembly method - Google Patents

Abstract

The improved tire 200, with a pre-cured tread pattern 10, for installation on either unvulcanized or vulcanized casing 100, is exposed. The improved pre-cured tread pattern 10 has a pair of continuous circumferential protrusions 60. One protrusion 60 extends axially outwards from each lateral surface 40,50 to the tread. The protrusions 60 provide a pathway for an airtight seal of the tread casing component on the lateral surfaces 40,50 during the vulcanization of tread 10 and casing 100. Assembly methods include a flat lay of tread 10 and casing 100, an expandable closure with air bladders expanding casing 100 into tread 10 (tread 10 expanding accordingly, resulting in an airtight seal), and an airtight seal at the annular protrusions 60 of tread 10, using heat and pressure to create uniform flow. The material that is not vulcanized is extruded outwards in a radial direction along the edges of the tire tread.

Claims (12)

1. The method of forming a pre-cured tread with an unvulcanized casing involves a tread with a pair of NS inner tread surfaces and a tread edge. This tread edge has lateral surfaces that intersect the inner tread surfaces. The process consists of steps involving placing the tread and casing into a flat mold and inserting an inflatable air bladder inside the casing; mold closing; inflating the air bladder in this way, firmly expanding the casing to contact the tread; the expanded tread making firm contact with the flat mold; and sealing the tread at the radial annular overhangs above the intersecting sections of each inner tread surface and lateral surface in an airtight manner. Heating and pressurizing the mold creates a uniform outward flow of casing material radially along the tread edge to the annular overhangs. 2. The method under claim 1 in which the annular projection extends outward from the surfaces along each side of the form. 3. The method under claim 1 in which the annular projections extend outward from the edges along each rim of the tire tread. 4. The procedure under claim 1 further comprises the assembly of an unvulcanized casing with a pair of pre-cured tops, each encasing a rounded, embossed core. 5. Mid-Production Product: This product is a pneumatic tire assembly, a smooth-curing unit with a pair of lateral surfaces and no tread pattern. This pneumatic tire assembly features a pre-cured annular tread and a traditional or other non-vulcanized green casing. This casing contains the carcass, belt structure, ribs, sidewalls, and all other components of the outer tire excluding the tread, and where the casing has a pair of uncured ribbed peaks. The casing is characterized by an outer diameter small enough that the annular tread can be positioned over the casing in a curing manner without the need for any physical stretching or diameter expansion of the tread to form the pneumatic tire assembly. 6. Intermediate product of production under claim 5: Pre-cured spherical embossed peaks, each peak having a largely non-expanding ring-shaped embossed core. 7. Intermediate product of production under claim 5, in which the uncured annular tread has a road contact surface, a pair of lateral surfaces extending inward radially from the outermost point axially of the road contact surface, the distance between the lateral surfaces defines the center of the tread, the tread thickness (T) at the center of the tread, the inner tread with a radial inner tread surface intersecting each lateral surface at a distance less than twice the thickness (I) of the tread as measured from the outermost point axially to the intersection of the inner tread surface and the lateral surface, and a pair of continuous circumferential extensions, one extension axially from each lateral surface and radially spaced closely together and generally above the intersection of the radial inner tread surface and the lateral surface, the extension has a radial inner surface that provides a way for the sealing of the outer tire assembly at the lateral surfaces so that air cannot enter or exit during vulcanization of the tread and the green casing, the radial inner surface of the extension. And at the surface portions, the lateral edges between the protrusions and the intersecting sections, and the radial shoulder of the casing above the shoulder in contact with the mold, and the lateral surfaces of the mold, cavities are formed for the flow of unvulcanized tire from the green casing outward along the axis of the lateral surface and radially up to the inner surface of the radial protrusion. These cavities, defined by the tread, casing, and mold, inward along the axis of the mold and radially adjacent to the flow of unvulcanized tire. When these cavities are filled with tire from the green casing, they effectively enclose the tread and create an invisible seam on the inner radial surface of the protrusion. 8. Intermediate product of manufacturing under claim 5, in which the casing has a pre-cured, rounded embossed top and an outer surface finish with a fine, rough texture. 9. Intermediate product of production under claim 6, where each pre-cured circular embossed peak is injection molded, enclosing a predominantly non-expandable circular embossed core ring. 10. Pre-cured tread for annular mounting on a prepared unvulcanized or vulcanized outer tire casing; the tread is made of elastomer material; the pre-cured tread has a radial outer contact surface; the tread has grooves that expand inward radially from the road contact surface; the tread material extends inward radially of the grooves, forming the inner tread layer; the inner tread layer has a radial inner surface and a radial outer surface; the tread, when externally shaped as an annulus, has a cross-section that includes the lateral and lateral surfaces, respectively, that expand inward radially and outward axially from the outermost axial point on the road contact surface to the outermost axial and innermost radial points of the inner tread layer at a distance less than twice the tread thickness; the tread thickness is determined as measured at the equatorial plane; improvements include a pair of continuous circumferential protrusions, one protruding outward radially. The axial lines from each lateral surface (first and second) and radially outward-facing near and generally above the intersection of the radial inner tread surface and the first or second lateral surface, at a distance of approximately 3 mm, each overhang has a radial inner surface that provides a way to seal the tread casing assembly at each lateral surface, so that air cannot pass through during the vulcanization of the tread with the casing. When the tread is in contact with the casing surfaces, the radial inner surface of each overhang, and at the section of the first and second lateral surfaces between the overhang and the intersection, and the casing surfaces form voids for the flow of unvulcanized rubber from the casing to expand outward axially of the first and second lateral surfaces and radially up to the inner surface of the radial overhang. This flow of unvulcanized rubber effectively encloses the tread and creates an invisible seam on the radial inner surface of the overhang. 11. Pre-aged tire tread improved according to claim 10, in which each protrusion has a trapezoidal cross-section. 12. Pre-aged tire tread improved in accordance with Claim 10, in which each section has a semicircular cross-section.