Method of molding a tire and mold therefor

• US 6,955,782 B1
• Filed: 11/24/1999
• Issued: 10/18/2005
• Est. Priority Date: 11/24/1999
• Status: Expired due to Fees

• Current Assignee: Goodyear Tire & Rubber Company
• Original Assignee: Goodyear Tire & Rubber Company
• Inventors: Ratliff, Billy Joe Jr.
• Primary Examiner(s): Mackey, James P.
• Application Number:
  US10/130,335
• Time in Patent Office: 2,155 Days
• Field of Search: 425/46, 264/326
• US Class Current: 264/326
• CPC Class Codes: B29D 2030/0612 Means for forming recesses or protrusions in the tyres, e.g. grooves or ribs, to create the tread or sidewalls patterns
• CPC Class Codes: B29D 2030/0618 Annular elements, e.g. rings, for moulding the tyre shoulder areas
• CPC Class Codes: B29D 30/0629 with radially movable sectors

Abstract

A tire molding method as disclosed wherein a segmented mold (2) has lugs (40) in the shoulder regions of the segments (4) with complimentary lug extensions (30) in the sidewall forming annular rings (6,8). The lug extensions (30) align with and form the appearance of a lug (40) that extends radially inward well into the sidewall of the tire (20). the resultant tire (20) and the mold (2) for making the tire (20) are less costly to fabricate than prior art segmented molds.

Claims

1. The method of molding a tire (20) in a segmented mold (2) having tread forming segments (4) and a pair of annular sidewall forming rings (6,8);

the method comprising the following steps;

placing an unvulcanized tire (20) into the segmented mold (2);

closing the mold (2) by a) radially contracting the tread forming segments (4) each tread forming segment (4) having a plurality of a shoulder tread element forming cavities (11) that form the entire radially outer surface of shoulder tread elements of the tire (20), the cavities (11) having circumferentially spaced axially outer ends (9), b) bringing into abutting relation the tread forming segments (4) and the annular sidewall forming rings (6,8), having a plurality of tread element extension forming surfaces (12) and a plurality of radially extending ridges (14) that extend to the location of the abutting relationship with the tread forming segments (4) and c) circumferentially aligning the plurality of tread element extension forming surfaces (12) of the annular sidewall forming rings (6,8) with the angular orientation of the axially outer ends (9) of the tread element forming cavities (11) of the tread forming segments (4);

applying heat and pressure curing the tire;

opening the mold (2); and

removing the cured tire (20).

2. The method of molding a tire (20) in a segmented mold (2) having tread forming segments (4) of claim 1 further includes the step of fabricating the segmented mold (2), and aligning the tread element extension forming surfaces (12) of the annular rings (6,8) with the axially outer ends (9) of the tread forming cavities (11) of the segments (4) when the mold (2) is in the closed position.

3. The method of molding a tire (20) in a segmented mold (2) having tread forming segments (4) of claim 2 wherein the step of fabricating the mold (2) includes the step of pitching the tread formed by the segments (4) in two or more distinct pitch sizes and arranging the two or more pitch sizes in a pitch sequence, and

pitching the tread element extension forming surfaces (12) formed by the annular rings (6,8) to correspond to the pitch sizes and the pitch sequence of the tread forming segments (4).

4. The method of molding a tire as set forth in claim 1 wherein the ridges have a substantially triangular cross section having an included angle of about 90°

.

5. The method of molding a tire as set forth in claim 1 wherein at the location where tread element forming cavities (11) of the tread forming segments (4) and the tread element extension forming surfaces (12) of the annular sidewall forming rings (6,8) abut, means are provided to form circumferentially extending groove in the tire.

8. The mold of claim 5 wherein the ridges have a substantially triangular cross section having an included angle of about 90°

.

6. A mold (2) for making a tire having a plurality of tread lugs (40), the mold (2) having four or more radially movable tread forming segments (4), the segments (4) when closed forming an annular tread ring, and an upper sidewall forming ring (8) and a lower sidewall forming ring (6), the segments (4) having a plurality of lug forming cavities (11), each lug forming cavity extending to a radially inner end (9) location, the mold being characterized by:

each sidewall forming ring (6,8) having a plurality of shoulder lug extension surfaces (12) circumferentially aligned with the lug forming cavities (11) of the mold segments (4) and having a plurality of radially extending ridges that extend to a location of the abutting relationship with the tread forming segments, and

wherein the segments alone form the radially outer surface of the tire.

7. The mold of claim 6 wherein the lug forming cavities (11) are pitched utilizing two or more pitch lengths, and the sidewall forming rings (6,8) have corresponding and aligned pitches for the lug extension surfaces (30).

9. The mold of claim 6 wherein the mold has means to form a small circumferentially extending groove at the location wherein the plurality of shoulder lug extension surfaces (12) of the sidewall forming rings (6,8) and the lug forming cavities (11) of the mold segments (4) are circumferentially aligned.