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: A CURING MOULD
2. Applicant(s)
NAME NATIONALITY ADDRESS
CEAT LIMITED Indian RPG HOUSE, 463, Dr. Annie Besant Road, Worli, Mumbai -Maharashtra 400030, 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.

BACKGROUND
[0001] Tyres are a crucial component of an automobile. In an automobile,
a tyre may be responsible for a plurality of functions. A final manufactured tyre may be required to conform to a plurality of quality standards, which may be based on the manner in which the tyre has been manufactured. During tyre manufacturing, a plurality of different components may be designed and attached together to form a preliminary uncured tyre, which is referred to as green tyre. The processed green tyre, once obtained, may then be cured in a curing press, as a final step for tyre manufacturing process. During curing, the green tyre may be subjected to high pressure in a mould, and subsequently, the tyre may be imprinted with tread pattern and side wall letter engraving to obtain a final manufactured tyre.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] The following detailed description references the drawings,
wherein:
[0003] FIG. 1 is a diagram depicting a front view of an example curing
mould, for manufacturing a tyre with minimal flash at parting line of the tyre, as per an implementation of the present subject matter;
[0004] FIG. 2 is a diagram depicting a sectional top view of an example
curing mould, for manufacturing a tyre with minimal flash at parting line of the tyre, as per an implementation of the present subject matter; and
[0005] FIG. 3 is a diagram depicting a cross section of an example toroidal
mould cavity of an example curing mould, as per an implementation of the present subject matter.
[0006] Throughout the drawings, identical reference numbers designate
similar, but not necessarily identical elements. 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.
DETAILED DESCRIPTION
[0007] Vehicles have become an essential requirement for private
individuals as well as for commercial purposes. As would be generally understood, a tyre is one of the most essential and critical components of a vehicle. During vehicle operation, a tyre is the only source of contact between the vehicle and the road, owing to which, a plurality of dynamics of the vehicle operation may be controlled by the tyre. The tyres may be responsible for guiding and maintaining the alignment and movement of a vehicle while driving. In addition, the tyres contribute to the safety of the vehicle while carrying loads, and when the automobile is to be halted by application of brakes.
[0008] Owing to the complexity of roles performed by the tyres in a vehicle,
it may be crucial for tyre manufacturers to manufacture a tyre which may conform to the adequate quality parameters. The quality parameters of the final manufactured tyre may be based on the manner in which the tyre has been manufactured, i.e., the manner in which the tyre has been subjected to various processes involved in the tyre manufacturing and the constructional features of the equipment used in tyre manufacturing.
[0009] Conventionally, rubber, along with other materials, may be used as
a raw material for manufacturing the tyres. A plurality of different components may be designed and assembled together, using a variety of techniques which involve both chemical and physical processes. For example, the raw materials may be processed into different components to form a toroidal shaped preliminary uncured tyre, which is also referred to as a green tyre.
[0010] Green tyre, once obtained, may then be cured when subjected to a
curing process in a curing press. As would be understood, curing may refer to

a process of applying pressure and heat energy to the green tyre in a toroidal mould cavity in the curing mould of the curing press. The heat energy thus applied enable chemical reactions between the rubber and other materials, to obtain its final shape. Thereafter, a tread pattern may be imprinted on the obtained tyre.
[0011] The curing mould of the curing press may be a toroidal mould cavity
to accommodate the green tyre. Specifically, the curing mould may include a bottom half mould and a top half mould. The green tyre may be accommodated in the bottom half mould, and the top half mould may be pressed against the bottom half mould.
[0012] The internal walls of each of the bottom half mould and the top half
mould, may be equipped with an internal protruded pattern, in the form of a plurality of protruded grooves, corresponding to the tread pattern required on the final manufactured tyre. A substantial amount of radially outward physical pressure may then be exerted on the green tyre from the axis of the toroidal mould cavity towards the internal walls of toroidal mould cavity of the curing mould.
[0013] As a result of application of substantial amount of pressure on the
green tyre, the green tyre may get pressed against the internal protruded tread pattern of the walls of the curing mould, and thereby, may get imprinted with tread pattern and side wall letter engraving.
[0014] The final tyre thus manufactured may have a parting line in the
direction of rotation of the tyre and perpendicular to the axis of the tyre, indicative of the two half moulds used during the tyre manufacturing. Further, the tread pattern imprinted of the final manufactured tyre may also be in the form of a circumferentially running continuous pattern along the parting line of the tyre on the outer surface of the tyre.
[0015] As would be understood, the constructional features of the bottom
half mould and the top half mould to form the toroidal mould cavity, along with

the plurality of protruded grooves to form the internal protruded pattern, may affect the quality of the tyre to be manufactured. For example, the pattern of the plurality of grooves and the height up to which the plurality of grooves may extend from the internal walls of the bottom half mould and top half mould towards the axis of the curing mould may result in a corresponding depth of tread pattern being imprinted on the tyre, thereby determining one of the quality parameters of the tyre.
[0016] However, the conventional approaches and the manner in which
the tyre is manufactured and subjected to internal protruded tread pattern in the curing mould may result in the final tyre having surface projections, referred to as flash. It might be the case that the toroidal mould cavity formed by the bottom half mould and the top half mould may have certain openings, holes, or any other interruptions. In such cases, the green tyre when cured in the curing mould, may cause extrusion of the material from the green tyre into such openings, thereby resulting in formation of flash. Owing to the joining of the bottom half mould and the top half mould for the formation of toroidal mould cavity in the curing mould, the flash may tend to form along the parting line, thereby also hampering the tread pattern on the tyre.
[0017] Generally, cutting instruments, such as scissors, may be used for
manually trimming the excess flash along the parting line of the final manufactured tyre. However, such manual trimming of excess flash at the parting line may result in either uneven trimming of flash or over-trimming of the flash, thereby resulting in the tyre getting damaged. Not only this may result in the degradation of quality of the tyres, it may also result in the raw material used for manufacturing tyres getting wasted. Further, continuous use of scissor by bare hands may create skin abrasion and other skin issues. While various methods of reducing excess flash exist, such conventional methods often affect the performance parameters of the tyre.
[0018] To this end, an improved curing mould for manufacturing a tyre with
minimal flash at parting line of the tyre is described. A green tyre may be cured,

as a final step for tyre manufacturing process, in a curing mould. As per an implementation of the present subject matter, the curing mould may include a bottom half mould and a top half mould. The bottom half mould and the top half mould may be a half toroidal shaped mould with a side wall of a thickness, such that the thickened side wall may define a circumference of the thickness of the bottom half mould and the top half mould. In another example, the curing mould may be of a material comprising forged steel.
[0019] The top half mould may be pressed against the bottom half mould
to form a toroidal mould cavity. Specifically, the circumference of the top half mould may be pressed against the circumference of the bottom half mould. The toroidal mould cavity thus formed may include a parting line perpendicular to the axis of the toroidal mould cavity, and is to accommodate a green tyre.
[0020] The curing mould may further include a plurality of protruded
grooves along the inner surface of each of the bottom half mould and the top half mould. In one example, the plurality of protruded grooves may extend radially towards the axis of the toroidal mould cavity up to a height in the range of about 1 millimetre to 8 millimetres.
[0021] In operation, the green tyre may be placed in the bottom half mould.
The top half mould may then be pressed against the bottom half mould. As would be understood, the plurality of protruded grooves on the inner surface of each of the bottom half mould and the top half mould may create a corresponding tread pattern on the outer surface of the green tyre. The tread pattern thus created on the outer surface of the green tyre may be in the form of a depression pattern up to a depth in the range of about 1 millimetre to 8 millimetres.
[0022] In another example, the plurality of protruded grooves on the inner
surface of each of the bottom half mould and the top half mould may be separated from the parting line by a longitudinal distance, when the top half mould is pressed against the bottom half mould along the parting line. In one example, such longitudinal distance of separation of the plurality of each of

the bottom half mould and the top half mould may be at least 2 millimetres. In such cases, the longitudinal distance may create a gap of at least 2 millimetres on each side between the imprinted tread pattern on each of the halves of the final manufactured tyre from the parting line.
[0023] In yet another example, the top half mould may be pressed against
the bottom half mould in such a manner that the thickness of the circumference of the top half mould to be pressed against the thickness of the circumference of the bottom half mould is the range of about 2 millimetres to 30 millimetres in a radially outward direction.
[0024] As would be appreciated, the curing mould, as described in the
approaches of the present subject matter, may provide for manufacturing tyres with minimal flash at parting line. The constructional features of the curing mould may reduce the flash forming tendency of the tyre during curing, thereby resulting in the final manufactured tyre having either minimal or no flash, as a result of which the need to manually trim the excess flash may be mitigated. Not only the appearance and overall quality of the tyre may be improved, but the raw material used for manufacturing the tyres may also be conserved. For example, the range of the height up to which the plurality of grooves may extend, may reduce the penetration of sharp protruded groove edges to the green tyre during curing. It may further reduce the pinching of green tyre rubber.
[0025] For another example, the minimum longitudinal distance between
the plurality of protruded grooves on the inner surface of each of the bottom half mould and the top half mould from the parting line, when the top half mould is pressed against the bottom half mould may also provide adequate strength to the edges of the protruded grooves to avoid the grooves getting bent or damaged during repeated moulding operation in continuous production. Conventionally, in cases where there may be inadequate gap between the grooves of each of the half moulds from the parting line, the grooves may tend to get bent or damaged during repeated moulding

operation, thereby resulting in gap between the top half mould and the bottom half mould, further resulting in facilitation of the flow of raw material and production of excess flash.
[0026] For yet another example, the range, as described in the
approaches of the present subject matter, of the thickness of circumference of the top half mould to be pressed against the thickness of circumference of bottom half mould may provide an optimal force acting on the contact surface of the two half moulds during the pressing, thereby improving the overall quality of the tyre to be manufactured. If the force, in conventional approaches, is applied to a large contact area, may result in insufficient pressure near the parting line, thereby the mould may tend to open during the moulding operation, and may again result in accumulation of excess flash at the parting line.
[0027] These, and other aspects, are described herein with reference to
the accompanying FIGS. 1-3. It should be noted that the description and figures relate to certain example, and should not be construed as a limitation to the present subject matter. It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and embodiments of the present subject matter, as well as specific examples, are intended to encompass equivalents thereof.
[0028] FIG. 1 is a diagram depicting a front view of an example curing
mould, for manufacturing a tyre with minimal flash at parting line of the tyre, during tyre manufacturing process, as per an implementation of the present subject matter. The curing mould 100 may be a part of a curing press (not shown in FIG. 1) well known to a person skilled in the art. Along with the curing mould 100, the curing press may include a plurality of other components (not shown in FIG. 1 for the sake of clarity).
[0029] As described previously, a green tyre, after undergoing other steps

involved in a tyre manufacturing process, may be subjected to a curing process in a curing press. Specifically, curing may refer to a process of applying pressure and heat energy to a green tyre in a toroidal mould cavity in a curing mould, such as curing mould 100 of a curing press.
[0030] In the foregoing description, various components and structural
aspects of the curing mould 100 have been explained with respect to FIGS. 1-2. FIG. 2 is a diagram depicting a sectional top view of an example curing mould, such as curing mould 100, for manufacturing a tyre with minimal flash at parting line of the tyre, during tyre manufacturing process, as per an implementation of the present subject matter.
[0031] The curing mould 100 may include a bottom half mould 102 and a
top half mould 104. The bottom half mould 102 and the top half mould 104 may be a half toroidal shaped mould with a side wall of a thickness, such that the thickened side wall may define a circumference of the thickness of the bottom half mould 102 and the top half mould 104 (as depicted in FIG. 2).
[0032] In another example, the curing mould 100 may be of a material
comprising forged steel. The use of forged steel to make the curing mould 100 may provide a smooth internal surface of the curing mould 100 and a good mould surface quality, thereby resulting in good serviceability of the curing mould 100 during curing process. However, it may be noted that the aforementioned example is only illustrative and should not be construed to limit the scope of the present subject matter. Any other material may also be used for making the curing mould 100 without deviating from the scope of the present subject matter.
[0033] Returning to the present example, the top half mould 104 may be
pressed against the bottom half mould 102 to form a toroidal mould cavity 106. Specifically, the circumference of the top half mould 104 may be pressed against the circumference of the bottom half mould 102. The toroidal mould cavity 106 thus formed may include a parting line 108 perpendicular to the axis of the toroidal mould cavity 106, and is to accommodate a green tyre (not

shown in FIG. 1).
[0034] In another example, the bottom half mould 102 and the top half
mould 104, during the pressing, may be aligned using any conventional alignment or a guiding means, well known to a person skilled in the art. During moulding operation, the bottom half mould 102 and the top half mould 104 may be subjected to a longitudinal movement with respect to each other. Such alignment or guiding means may properly align each of the half moulds of the mould cavity 100, thereby ensuring manufacturing tyre of desired shape and dimensions.
[0035] Returning to the present example, the curing mould 100 may
further include a plurality of protruded grooves 110 (as would be described in further details in FIG. 3) along the inner surface of each of the bottom half mould 102 and the top half mould 104. The plurality of protruded grooves 110 may form an internal tread pattern along the inner surface of the bottom half mould 102 and the top half mould 104. In one example, the plurality of protruded grooves 110 may extend radially towards the axis of the toroidal mould cavity 106 up to a height in the range of about 1 millimetre to 8 millimetres.
[0036] It may be noted that although the plurality of protruded grooves 110
has been shown only with respect to one side of the bottom half mould 102 and the top half mould 104 of the toroidal mould cavity 106 in FIG. 1 for the sake of clarity, it may be understood that the bottom half mould 102 and the top half mould 104 are a half toroidal shaped mould, and the plurality of grooves 110 may be present circumferentially throughout the inner surface of each of the bottom half mould 102 and the top half mould 104 (as depicted in FIG. 2).
[0037] In operation, the green tyre may be placed in the bottom half mould
102. The green tyre may occupy a space in the bottom half mould up to a certain radius, depicted as 112 in FIG. 1. The top half mould 104 may then be pressed against the bottom half mould 102. In another example, the top half

mould 104 may be pressed against the bottom half mould 102 in such a manner that the thickness of the circumference of the top half mould 102 to be pressed against the thickness of the circumference of the bottom half mould 104 is the range of about 2 millimetres to 30 millimetres in a radially outward direction, depicted as 114 in FIG. 1.
[0038] Thereafter, a substantial amount of pressure may be exerted to the
green tyre using any conventional technique known to a person skill in the art. The pressure thus exerted on the green tyre may cause the green tyre to get pressed against the plurality of protruded grooves 110 along the inner surface of the bottom half mould 102 and the top half mould 104.
[0039] The plurality of protruded grooves 110 may create a corresponding
tread pattern on the outer surface of the green tyre. The tread pattern thus created on the outer surface of the green tyre may be in the form of a depression pattern corresponding to the internal tread pattern. In one example, the depression pattern may be up to a depth in the range of about 1 millimetre to 8 millimetres.
[0040] The final tyre with the imprinted tread pattern thus obtained may
then be sent to quality check, or any other step involved in the manufacturing and production of tyres. Such tyres may be used in any vehicles, such as a two-wheeler or a heavy transit vehicle without deviating from scope of the present subject matter. The curing mould 100 and its corresponding constructional features may be specifically adapted to manufacture a specific type of tyre.
[0041] The constructional features of the curing mould 100, as per the
approaches of the present subject matter, may reduce the flash forming tendency of the tyre during curing, thereby resulting in the final manufactured tyre having either minimal or no flash, as a further result of which the need to manually trim the excess flash may be mitigated. The manner in which the ranges of various constructional aspects of the plurality of grooves 110 are to cause the final manufactured tyre to have minimal or no flash, is explained in

further details in conjunction with FIG. 3.
[0042] FIG. 3 is a diagram depicting a cross section of an example toroidal
mould cavity of an example curing mould, as per an implementation of the present subject matter. The toroidal mould cavity may be a similar toroidal mould cavity 106 as described in FIG. 1.
[0043] As described previously, the bottom half mould 102 and the top half
mould 104 may include a plurality of protruded grooves 110-1 and 110-2 respectively along their inner surface to form an internal tread pattern. Although the protruded grooves 110 in FIG. 3 have been shown as conical-shaped grooves 110, it may be noted that the same is only illustrative. The plurality of protruded grooves 110 may be in the form of cylindrical, conical, or any other three-dimensional geometrical shape so as to form the internal tread pattern, without deviating from the scope of the present subject matter.
[0044] In one example, the plurality of protruded grooves 110 may extend
radially towards the axis of the toroidal mould cavity 106 up to a certain height, depicted as 302 in FIG. 3. In another example, the height 302 may be in the range of about 1 millimetre to 8 millimetres.
[0045] In another example, the conventional mould cavity with a plurality
of conventional protruded grooves may be optimized to implement the approaches of the present subject matter. In such cases, it may be case that the conventional grooves may extend up to a height which may be non-desirable to implement the approaches of the present subject matter, e.g., depicted as 304 in FIG. 3. In such cases, the height up to which the grooves may extend from the inner surface of each of the bottom half mould 102 and the top half mould 104 may be trimmed up to a required height, depicted as 306 in FIG. 3, so as to conform with the standards laid down as per approaches of the present subject matter.
[0046] In yet another example, the plurality of protruded grooves 110 may
be made of a same material as that of the bottom half mould 102 and the top

half mould 104. In yet another example, the plurality of protruded grooves 110 may be made of a material comprising forged steel.
[0047] Further, as mentioned previously, although the plurality of
protruded grooves 110-1 and 110-2 has been shown only with respect to one side of the bottom half mould 102 and the top half mould 104 of the toroidal mould cavity 106, it may be understood that the bottom half mould 102 and the top half mould 104 are a half toroidal shaped mould, and the plurality of grooves 110 are present circumferentially throughout the inner surface of each of the bottom half mould 102 and the top half mould 104.
[0048] In operation, the top half mould 104 may be pressed against the
bottom half mould 102 to form the toroidal cavity 106. The toroidal cavity 106 may accommodate the green tyre up to a certain radius, depicted as 112 from the axis of the toroidal mould cavity 106. Thereafter, upon exertion of a substantial amount of pressure to the green tyre, it may cause the green tyre to get pressed against the plurality of protruded grooves 110 of each of the half moulds.
[0049] The plurality of protruded grooves 110 may create a corresponding
tread pattern on the outer surface of the green tyre. The tread pattern thus created on the outer surface of the green tyre may be in the form of a depression pattern corresponding to the internal tread pattern.
[0050] Further, the plurality of protruded grooves 110 on the inner surface
of each of the bottom half mould 102 and the top half mould 104 may be separated by a longitudinal distance from the parting line, depicted as 308 and 310 respectively in FIG. 3, when the top half mould 104 is pressed against the bottom half mould 102 along the parting line 108. In one example, such longitudinal distance 308 and 310 may be at least 2 millimetres each. Such longitudinal distance 308 and 310 between the protruded grooves 110-1 of the bottom half mould 102 and the protruded grooves 110-2 of the top half mould 104 respectively may create a certain gap, for example at least 2 millimetres on each side, between the imprinted tread pattern on each of the

halves of the final manufactured tyre from the parting line.
[0051] Although examples for the present disclosure have been described
in language specific to structural features and/or methods, it should be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed and explained as examples of the present disclosure.

I/We Claim:
1. A curing mould for manufacturing a tyre with minimal flash at parting
line of the tyre, the curing mould comprising:
a bottom half mould;
a top half mould, wherein the top half mould is to press against the bottom half mould to form a toroidal mould cavity with a parting line, wherein the parting line is perpendicular to axis of the toroidal mould cavity; and
a plurality of protruded grooves along the inner surface of each of the bottom half mould and the top half mould, such that the plurality of protruded grooves extends radially towards the axis of the toroidal mould cavity up to a height in the range of about 1 millimetre to 8 millimetres.
2. The curing mould as claimed in claim 1, wherein the toroidal mould cavity is to accommodate a green tyre.
3. The curing mould as claimed in claim 1, wherein the plurality of grooves of each of the bottom half mould and the top half mould are separated by a longitudinal distance of at least 2 millimetres from the parting line, when the top half mould is pressed against the bottom half mould along the parting line.
4. The curing mould as claimed in claim 1, wherein the plurality of protruded grooves is to create a corresponding tread pattern on the outer surface of the green tyre.
5. The curing mould as claimed in claim 4, wherein the tread pattern is a depression pattern on the outer surface of the green tyre corresponding to the plurality of protruded grooves.

6. The curing mould as claimed in claim 5, wherein the depression pattern of the tread pattern is up to a depth in the range of about 1 millimetre to 8 millimetres from the outer surface of the green tyre towards axis of the green tyre.
7. The curing mould as claimed in claim 1, wherein the top half mould and the bottom half mould are a half toroidal shaped mould with a side wall of a thickness, such that the thickened side wall is to define a circumference of a thickness of the bottom half mould and the top half mould.
8. The curing mould as claimed in claim 7, wherein the circumference of the top half mould is to be pressed against the circumference of the bottom half mould.
9. The curing mould as claimed in claim 7, wherein the thickness of the circumference of the top half mould to be pressed against the thickness of the circumference of the bottom half mould is in the range of about 2 millimetre to 30 millimetres in a radially outward direction.
10. The curing mould as claimed in claim 1, wherein the curing mould is of a material comprising forged steel.