Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – Tire body building type
Reexamination Certificate
1998-10-27
2001-09-18
Knable, Geoffrey L. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
Tire body building type
C152S209600, C156S129000, C425S035000, C425S043000
Reexamination Certificate
active
06290810
ABSTRACT:
TECHNICAL FIELD
This invention relates to a mold for curing a precured tread to a tire casing.
BACKGROUND ART
Historically the use of precured treads was limited to retreaded tires exclusively. Tire casings are designed to survive several times longer than the tread. This is particularly true of truck tires and low aspect ratio passenger tires.
The Goodyear Tire & Rubber Company in the late 1980's introduced the unicircle precured injected molded tread. This precured tread is disclosed in European Patent publication 0-464-660A1. This annular or arcutely shaped tread had short annular wings radially inwardly extending. The wings were flexible and adapted to accommodate casings of various axial widths. This tread introduced high pressure injection molded rubber compounds having excellent wear and rolling resistance properties. Materials used in tread rubber compounds have also been improved making it feasible to transfer compression high quality treads for tires which can also achieve excellent wear and performance characteristics.
Later development efforts were concentrated on improved adhesion of the tread to the casing and in particular better ways of adhering the wing edge to the casing. On May 24, 1994, U.S. Pat. No. 5,313,745 issued to Carl L. Mace, Jr., et al. This patent related to a tread edge grinding method which effectively created a circumferential edge enabling the cushion gum rubber to migrate over the chamfer effectively locking the annular wing of the precured tread to the cushion gum in the casing. The advancement in the overall adhesion properties of the tread to casing bond coupled with the ability to meet or surpass the performance of the conventional molded new tires means that it is now feasible for new tires to be made using precured treads. One aspect of the present invention describes an improved mold for facilitating the assembling of a precured tread to a previously unvulcanized casing.
DESCRIPTION OF THE INVENTION
Summary of the Invention A tire and a mold
20
for curing a precured tread
10
to a tire casing
100
is disclosed. The tire has casing and a precured tread, the precured tread
10
has a pair of lateral ends and a radially outer tread surface having a diameter and contour built to the same diameter and contour as the mold. The mold
20
has a first annular portion
24
and a second annular portion
44
. The first annular portion
24
has a sidewall supporting member
27
, the sidewall supporting member
27
has a bead forming end
29
and tread lateral end support
18
. The first annular portion
24
further has a tread supporting member
28
integrally attached and generally oriented normal to the sidewall supporting member
27
at the location of the tread lateral end support
18
of the sidewall supporting member
27
. The tread supporting member
28
has a smooth axially contoured annular surface for contacting the radially outer surface of the precured tread
10
and a first end
51
. The second annular portion
44
has a sidewall member
47
and tread lateral end supporting member
48
.
The second annular portion
44
has a first end
50
and a second end
52
. The first end
50
is adjacent to the tread lateral end supporting member
48
. The first end
50
is also aligned with the first end
51
of the first annular portion
44
when the mold
20
is closed forming a cavity
53
for the precured tread
10
and casing
100
assembly
200
and the second end
52
is located at a bead forming end
49
of the second annular portion
44
.
The mold
20
also includes a pair of movable annular portions, the annular portions
12
,
14
being adapted to removably engage the bead forming ends
29
,
49
of the first and second annular portions
24
,
44
. The mold
20
further includes an inflatable bladder
23
for insertion into the casing
100
when the casing
100
is enclosed in the cavity
53
of the mold
20
. In the preferred embodiment the first end
51
of the tread supporting member
28
of the first annular portion
24
is located at the tread lateral end
48
supporting member located adjacent relative to the sidewall support member
47
of the second annular
44
. Preferably the tread supporting member
28
has a port
54
for venting or pressurizing void spaces between the tread
10
and the smooth annular surface of the tread supporting member
28
of the first annular
24
.
Definitions. “Axial” and “axially” means the lines or directions that are parallel to the axis of rotation of the tire.
“Buffed” means a procedure whereby the surface of an elastomeric tread or casing is roughened. The roughening removes oxidized material and permits better bonding.
“Casing” means the carcass, belt structure, beads, sidewalls, and all other components of the tire including a layer of unvulcanized rubber to facilitate the assembly of the tread, the tread and undertread being excluded. The casing may be new, unvulcanized rubber or previously vulcanized rubber to be fitted with a new precured tread.
“Equatorial Plane (EP)” means the plane perpendicular to the tire's axis of rotation and passing through the center of its tread.
“Pneumatic tire” means a laminated mechanical device of generally toroidal shape (usually an open torus) having beads and a tread and made of rubber, chemicals, fabric and steel or other materials. When mounted on the wheel of a motor vehicle, the tire through its tread provides a traction and contains the fluid or gaseous matter, usually air, that sustains the vehicle load.
“Pre-cured component” means a component at least partially vulcanized prior to assembly with other components.
“Radial” and “radially” mean directions radially toward or away from the axis of rotation of the tire.
“Replacement tread” as used herein refers to a premolded and precured tread.
“Retreading” means the procedure of refurbishing a tread worn tire be removing the old tread and replacing it with a precured tread or a “hot capped” tread.
“Tread” means a molded rubber component which, when bonded to a tire casing, includes that portion of the tire which comes into contact with the road when the tire is normally inflated and under normal load.
“Wings” means the radial inward extension of the tread located at axial extremes of the tread, the inner surface of the wing being an extension of the casing contacting surface of the tread.
REFERENCES:
patent: 1361764 (1920-12-01), Hibbs
patent: 3057011 (1962-10-01), Knox
patent: 3216062 (1965-11-01), Shaver et al.
patent: 4111732 (1978-09-01), MacMillian
patent: 4229245 (1980-10-01), Pringle
patent: 4562031 (1985-12-01), Rossi
patent: 4883415 (1989-11-01), Solvadori
patent: 5141424 (1992-08-01), Christof
patent: 5201975 (1993-04-01), Holroyd et al.
patent: 5536348 (1996-07-01), Chlebina et al.
patent: 2711118 (1978-09-01), None
patent: 0505814 (1992-09-01), None
Laurich Thomas Andrew
Yovichin Albert James
King David L
Knable Geoffrey L.
The Goodyear Tire & Rubber Company
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