FORM 2
THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10, rule 13)
1. Title of the invention: TIRE MOLD FOR CURING A PNEUMATIC TIRE
2. Applicant(s)
NAME NATIONALITY ADDRESS
CEAT LIMITED Indian CEAT Ltd At: Get Muwala Po: Chandrapura Ta: Halol - 389 350 Dist: Panchmahal, Gujarat, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

TECHNICAL FIELD
[0001] The present subject matter relates, in general, to a tire mold and,
particularly, to a tire mold having a ventless bead ring.
BACKGROUND
[0002] Tires are a crucial component of an automobile. In an automobile, a
tire is responsible for several functions. A tire may be required to conform to a plurality of industry and safety standards, owing to which, the steps involved in any tire manufacturing process may be considered crucial. Numerous components are designed and attached together to form a preliminary uncured tire, which is referred to as a green tire. The green tire is then vulcanized in a tire mold to obtain a tire as a finished product.
[0003] During a tire vulcanization process, the uncured pneumatic tire is
placed in the tire mold. The tire mold comprises a pair of upper and lower side plates, and a plurality of segments that, in a closed state of the tire mold, approach together and close the uncured pneumatic tire. In the closed state of the tire mold, a part of the outer peripheral surface of the side plate abuts a part of the inner peripheral surface of the segment. The uncured pneumatic tire is accommodated in a cavity enclosed by the tire mold and a bladder. The uncured pneumatic tire is heated while being pressurized at the same time. The rubber composition of the uncured pneumatic tire flows in the cavity by pressurization and heating. The rubber undergoes a crosslinking reaction by heating, and the pneumatic tire is obtained.
[0004] Reference is made to Figure 1 that illustrates a cross-sectional view
of a conventional side plate 100 of a tire mold. The figure shows the side plate 100 of the tire mold comprising a mold bead ring 102 for forming a bead portion of a pneumatic tire. During the vulcanization process, when the uncured pneumatic tire is placed in the tire mold, the bead portion of the uncured pneumatic tire rests on the mold bead ring 102. In the mold bead ring 102,

there is provided a plurality of vent holes 104 throughout the circumference of the mold bead ring 102 for venting out the air in between the uncured pneumatic tire and the tire mold
BRIEF DESCRIPTION OF THE FIGURES
[0005] The detailed description is described with reference to the
accompanying figures. In the figures, the left-most digit(s) of a reference
number identifies the figure in which the reference number first appears. The
same numbers are used throughout the drawings to reference like features and
components.
[0006] Fig. 1 illustrates an isomeric view of a side plate of a conventional
tire mold for curing a pneumatic in accordance with the prior art.
[0007] Fig. 2 illustrates an isomeric view of a side plate of a tire mold for
curing a pneumatic tire for a wheel assembly, according to an embodiment of
the present subject matter.
[0008] Fig. 3 illustrates an isomeric cross-sectional view of a lower and an
upper profile detail of a tire mold and a mold bead ring having a first portion
and a second portion, according to an embodiment of the present subject
matter.
[0009] Fig. 4 illustrates an exploded cross-sectional view of a tire mold and
a mold bead ring having a first portion and a second portion, according to an
embodiment of the present subject matter.
[0010] The figures are not necessarily to scale, and the size of some parts
may be exaggerated to more clearly illustrate the example shown. Moreover,
the drawings provide examples and/or implementations consistent with the
description; however, the description is not limited to the examples and/or
implementations provided in the drawings.
DESCRIPTION OF EMBODIMENTS

[0011] The present subject matter relates to a tire mold for curing a
pneumatic tire for a wheel assembly.
[0012] A mold bead ring is a portion in a side plate of the tire mold having
a top side plate and a bottom side plate where a bead portion of an uncured pneumatic tire rests on the tire mold during a tire curing process. A plurality of air vent holes is provided on the mold bead ring of the top side plate and the bottom side plate of the tire mold for venting out the air in between the uncured pneumatic tire and the tire mold. During vulcanization molding, if air is accumulated in between the uncured pneumatic tire and the tire mold, it may result in defects in the pneumatic tire surface which degrade the quality of the tire and often even the durability of the pneumatic tire. The plurality of air vent holes in the mold bead ring of the tire mold dispenses the air outside of the tire mold to prevent defects in the pneumatic tire.
[0013] However, along with the air, rubber of the uncured pneumatic tire
flows into the plurality of air vent holes during the vulcanization process. Thus, the plurality of air vent holes forms a protruding structure on the pneumatic tire surface called a vent fur. In some cases, a vent fur may have a length of, for example, about 7.5 mm, and in some cases, 20 mm or more owing to the rubber of the pneumatic tire being vulcanized entering into the plurality of vent holes.
[0014] The vent furs formed on the surface of the pneumatic tire are
removed by a trimming process that is carried out after vulcanization molding in order to improve the appearance of the pneumatic tire. However, this extra step of removing the vent furs from the pneumatic tire’s surface hinders the production efficiency in the pneumatic tire manufacturing process. The additional step of vent fur removal also adds extra cost, time, and labor to the pneumatic tire manufacturing process. Furthermore, even after the removal of

the vent furs from the pneumatic tire surface, some part of the vent fur remains on the pneumatic tire surface as vent fur marks.
[0015] In addition, the vent furs results in wastage of a significant amount
of rubber. For instance, each vent fur may weigh around 0.1 gm. Considering that typically a standard tire manufacturing plant may produce around 10,000-20,000 tires per day, a significant amount of rubber wastage occurs due to the vent furs.
[0016] Accordingly, the present subject matter is related to a tire mold for
curing a pneumatic tire for a wheel assembly that addresses the above-
described shortcomings associated with creation and removal of vent furs. In
accordance with an embodiment of the present subject matter, the tire mold
comprises a plurality of segments arranged to form an annular ring. In
operation, an inner molding surface of the annular ring interfaces with an
uncured pneumatic tire to form an outer tread surface of the pneumatic tire.
The tire mold also comprises a pair of side plates comprising a top side plate
and a bottom side plate, on either side of the inner molding surface of the
annular ring for forming a shoulder portion of the pneumatic tire. Each of the
top side plate and a bottom side plate comprise a mold bead ring for forming a
bead portion of the pneumatic tire. The mold bead ring comprises a first portion
and a second portion, joined together, and having a circumferential passage
formed at an intersection of the first portion and the second portion to release
air present in between the uncured pneumatic tire and the tire mold.
[0017] In accordance with embodiments of the present subject matter, the
tire mold for curing a pneumatic tire eliminates the plurality of air vent holes in the mold bead ring of the top side plate and the bottom side plate of the tire mold as instead of providing the plurality of air vent holes, the presently described mold bead ring of the top side plate and the bottom side plate each

have the circumferential passage to allow air trapped between the uncured pneumatic tire and the tire mold to escape.
[0018] In an example embodiment, the first portion of the mold bead ring
has a substantially L-shaped cross-section comprising a horizontal part and a vertical part. The second portion of the mold bead ring has a ring-like structure with a first circumferential edge and a second circumferential edge. The second portion of the mold bead ring is coupled to the horizontal part of the first portion such that the circumferential passage is located between an edge of the vertical part and the second circumferential edge of the second portion.
[0019] Further, in an example embodiment of the present subject matter,
the tire mold comprises a knurling design beneath the circumferential passage on an inner surface of the edge of the vertical part of the first portion and an inner surface of the second circumferential edge of the second portion of the mold bead ring. The knurling design is a diamond knurling, in an example. The knurling design prevents clogging of the circumferential passage due to the accommodation of rubber of the uncured pneumatic tire into the circumferential passage.
[0020] Hence, the present subject matter provides pneumatic tires which
are free of vent furs. This results in reduction in cost and time involved in the
tire manufacturing process as the disclosed tire mold for curing the pneumatic
tire manufactures pneumatic tires free of vent furs which eliminates the extra
step of removal of the vent furs from the surface of the pneumatic tire. Hence,
present subject matter provides for reducing labor and waste production during
the tire manufacturing process. Also, the disclosed tire mold for curing the
pneumatic tire makes the tire manufacturing process less complex.
[0021] The present subject matter is further described with reference to the
accompanying figures. It should be noted that the description and figures merely illustrate the principles of the present subject matter. It is thus

understood that various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[0022] Although embodiments for methods and systems for the present
subject matter have been described in a language specific to structural features and/or methods, it is to be understood that the present subject matter is not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as exemplary embodiments for the present subject matter.
[0023] Figure 2 illustrates an isomeric view of a side plate of the tire mold
for curing a pneumatic tire for a wheel assembly, in accordance with one embodiment of the present subject matter.
[0024] During a tire vulcanization process, the uncured pneumatic tire is
put into the tire mold. The tire mold comprises a pair of side plates 200 comprising a top side plate and a bottom side plate, and a plurality of segments of the tire mold for closing the uncured pneumatic tire inside the tire mold. Once the tire mold is assembled with the side plates 200 and the plurality of segments of the tire mold, a part of the outer peripheral surface of the side plates abuts a part of the inner peripheral surface of the segments. The uncured pneumatic tire is accommodated in a cavity formed by the plurality of segments and the side plates 200.
[0025] In accordance with embodiments of the present subject matter,
figure 2 further shows a side plate having a mold bead ring for forming a bead portion of the pneumatic tire, where the bead portion of the uncured pneumatic tire rests on the tire mold during a tire curing process. Each of the top side plate and a bottom side plate comprises a mold bead ring.

[0026] Wheels for automobiles, bicycles, etc. are made with a small slot or
groove into which the bead portion of the pneumatic tire rests. When the pneumatic tire is properly inflated, the air pressure within the pneumatic tire retains the bead in the small slot or the groove. The bead portion of the pneumatic tire comes into contact with a rim of the wheel of a vehicle when the pneumatic tire is incorporated into the rim. The bead portion includes a bead bottom surface that contacts a seat surface of the rim, an axially outer surface that contacts a flange of the rim, and a bead heel surface between the bead bottom surface and the axially outer surface. The bottom surface of the bead faces inward in the radial direction. The axially outer surface faces outward in the axial direction. The bead heel surface is bent between the bead bottom surface and the bead outer surface. The bottom surface of the bead, the outer surface in the axial direction, and the bead heel surface are preferably formed as smooth surfaces from the viewpoint of adhesion to the rim of the wheel of a vehicle.
[0027] In accordance with embodiments of the present subject matter, the
mold bead ring is divided into two parts and comprises a first portion 202 and a second portion 204, joined together to form the mold bead ring of the tire mold.
[0028] The first portion 202 of the mold bead ring has a substantially L-
shaped cross-section comprising a horizontal part and a vertical part, and the second portion 204 of the mold bead ring has a ring-like structure with a first circumferential edge 210 and a second circumferential edge 212. The second portion 204 of the mold bead ring is coupled to the horizontal part of the first portion 202 such that a circumferential passage 206 is located between an edge of the vertical part and a second circumferential edge 212 of the second portion 204. The first circumferential edge 210 of the second portion 204 is

welded on an edge of the tire mold where the first circumferential edge 210 of
the second portion 204 of the mold bead ring rests on the tire mold.
[0029] Needless to add, other embodiments where the first circumferential
edge 210 of the second portion 204 are joined on the edge of the tire mold by
any other joining method, for example, by brazing are also possible.
[0030] The first portion 202 and the second portion 204 of the mold bead
ring of the tire mold are made of mild steel or aluminum in an example.As described previously, a plurality of air vent holes 104 as shown in figure 1 is provided on the mold bead ring of the pair of side plates 100 of the tire mold for venting out the air in between the uncured pneumatic tire and the tire mold. The rubber of the uncured pneumatic tire generally flows into the plurality of air vent holes 104 during the vulcanization process along with the air. The plurality of air vent holes 104 in the mold bead ring 102 of the side plates 100 of the tire mold discharges the air outside of the tire mold to prevent defects in the pneumatic tire. However, as discussed previously, the plurality of air vent holes 104 leads to formation of a protruding structure on the pneumatic tire surface called a vent fur due the rubber of the pneumatic tire vulcanized entering into the plurality of vent holes 104.
[0031] In contrast to the conventional mold bead ring having the plurality of
air vent holes 104, in accordance with embodiments of the present subject matter, as shown in figure 2, the tire mold is made of two portions and has the circumferential passage 206 which is formed at an intersection of the first portion 202 and the second portion 204 of the mold bead ring. The circumferential passage 206 formed between the intersection of the first portion 202 and the second portion 204 extends throughout a circumference of the mold bead ring of the pair of side plates 200 of the tire mold. Hence, the circumferential passage 206 of the tire mold serves the purpose of the plurality of air vent holes.

[0032] Figure 3 illustrates an isomeric cross-sectional view of a lower and
an upper profile detail of a tire mold and a mold bead ring of one of the side
plates 200 of the tire mold. As will be apparent from the foregoing discussion,
each of the side plates 200 of the tire mold is symmetric and hence the
explanation provided with respect to one is applicable to the other as well.
[0033] The mold bead ring has two portions as mentioned above, namely,
the first portion 202 and the second portion 204. The figure shows the first portion 202 and the second portion 204 assembled together to form the mold bead ring of either of the pair of side plates 200 of the tire mold. A first circumferential edge 210 of the second portion 204 is welded on an edge of the tire mold where the first circumferential edge 210 of the second portion 204 of the mold bead ring rests on the tire mold. Further, in one example embodiment, the first portion 202 of the mold bead ring may include a notch 208 that forms a part of the circumferential passage 206 on the horizontal part, between the vertical part and the first circumferential edge 210 of the second portion 204 of mold bead ring. The notch 208 is having a square or a circular cross-section.
[0034] Figure 4 illustrates an exploded cross-sectional view of a tire mold
and a mold bead ring of the tire mold having a first portion 202 and a second portion 204, according to an embodiment of the present subject matter. It shows a weld area 400 for welding the second portion 204 with the first portion 202 of the mold bead ring.
[0035] In accordance with embodiments of the present subject matter,
there is provided a plurality of screws (not shown) at an inner surface of the second portion 204 of the mold bead ring for fastening the second portion 204 of the mold bead ring to the first portion 202 of the mold bead ring, where the second portion 204 of the mold bead ring is welded on an edge of the tire mold where a first circumferential edge 210 of the second portion 204 of the mold

bead ring rests on the tire mold such that the circumferential passage 206 is
formed at the intersection of the first portion 202 and the second portion 204.
[0036] In accordance with embodiments of the present subject matter, as
shown in figure 4, there is provided a knurling area 402 for providing a knurling design, on the inner surface of the edge of the vertical part of the first portion 202 and an inner surface of the second circumferential edge 212 of the second portion 204 of the mold bead ring. Knurling is a manufacturing process, typically conducted on a lathe, whereby a pattern of straight, angled or crossed lines is rolled into a material.
[0037] In accordance with embodiments of the present subject matter, the
knurling design is a diamond knurling configured to prevent clogging of the circumferential passage due to accommodation of rubber of the uncured pneumatic tire into the circumferential passage 206.
[0038] In accordance with embodiments of the present subject matter, the
present disclosure also provides a method of manufacturing a pneumatic tire. The disclosed method of manufacturing provides pneumatic tires which are free of vent furs. As discussed previously, this results in reduction in cost and time involved in the tire manufacturing process as the disclosed method of manufacturing the pneumatic tires manufactures pneumatic tires free of vent furs which eliminates the extra step of removal of the vent furs from the surface of the pneumatic tire. Hence, present subject matter provides for reducing labor and waste production during the tire manufacturing process. Also, the disclosed tire manufacturing process less complex.
[0039] Although the subject matter has been described in considerable
detail with reference to certain examples and implementations thereof, other implementations are possible. As such, the present disclosure should not be limited to the description of the preferred examples and implementations contained therein.

I/We Claim:
1. A tire mold for curing a pneumatic tire for a wheel assembly, the tire
mold comprising:
a plurality of segments arranged to form an annular ring, wherein an inner molding surface of the annular ring is to interface with an uncured pneumatic tire to form an outer tread surface of the pneumatic tire,
a pair of side plates (200) comprising a top side plate and a bottom side plate, on either side of the inner molding surface of the annular ring for forming a shoulder portion of the pneumatic tire, wherein
each of the top side plate and a bottom side plate comprise a mold bead ring for forming a bead portion of the pneumatic tire, wherein the mold bead ring comprises
a first portion (202) and a second portion (204), joined together, having a circumferential passage (206) formed at an intersection of the first portion (202) and the second portion (204) to release air in between the uncured pneumatic tire and the tire mold.
2. The tire mold as claimed in claim 1, wherein the first portion (202) of the mold bead ring has a substantially L-shaped cross-section comprising a horizontal part and a vertical part, and wherein the second portion (204) of the mold bead ring has a ring-like structure with a first circumferential edge (210) and a second circumferential edge (212), the second portion (204) of the mold bead ring is coupled to the horizontal part of the first portion (202) such that the circumferential passage (206) is located between an edge of the vertical part and the second circumferential edge (212) of the second portion (204).
3. The tire mold as claimed in claim 2, wherein the first circumferential edge (210) of the second portion (204) is welded on an edge of the tire mold

where the first circumferential edge (210) of the second portion (204) of the mold bead ring rests on the tire mold.
4. The tire mold as claimed in claim 1 comprises a plurality of screws at an inner surface of the second portion (204) of the mold bead ring for fastening the second portion (204) of the mold bead ring on the tire mold such that the circumferential passage (206) is formed at the intersection of the first portion (202) and the second portion (204).
5. The tire mold as claimed in claim 1, comprises a knurling design beneath the circumferential passage (206) on an inner surface of the edge of the vertical part of the first portion (202) and an inner surface of the second circumferential edge (212) of the second portion (204) of the mold bead ring.
6. The tire mold as claimed in claim 5, wherein the knurling design is a diamond knurling configured to prevent clogging of the circumferential passage due to accommodation of rubber of the uncured pneumatic tire into the circumferential passage (206).
7. The tire mold as claimed in claim 1, wherein the circumferential passage (206) formed between an intersection of the first portion (202) and the second portion (204) extends throughout a circumference of the mold bead ring of the tire mold.
8. The tire mold as claimed in claim 1, wherein the first portion (202) and the second portion (204) of the mold bead ring of the tire mold are made of mild steel or aluminum.

9. The tire mold as claimed in claim 1, wherein the first portion (202) of the mold bead ring includes a notch (208) that forms a part of the circumferential passage (206) on the horizontal part, between the vertical part and the first circumferential edge (210) of the second portion (204) of the mold bead ring.
10. A method of manufacturing a pneumatic tire for a wheel assembly, the method comprising curing the pneumatic tire in the tire mold as claimed in any one of the preceding claims 1 to 8.