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 BUILDING DRUM
2. Applicant(s)
NAME NATIONALITY ADDRESS
CEAT LIMITED Indian CEAT Ltd At: Get Muwala Po: Chandrapura Ta: Halol, Dist: Panchmahal, Gujarat 389 350, 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 invention relates, in general, to tire manufacturing and,
particularly but not exclusively, to a tire building drum for manufacturing green tires.
BACKGROUND
[0002] In a tire manufacturing process, a tire building drum is used in the initial
stage of tire manufacturing process for producing a green tire (uncured tires).
During this process, the foundational layers of the tire, known as carcass plies, are
wounded around the tire building drum’s circumferential margins while the tire
building drum is in a collapsed state. Subsequently, the tire building drum
undergoes outward expansion to create shoulders for securing the bead rings in
place. This expansion of the tire building drum also stretches the carcass plies,
generating the necessary tension for shaping the green tire. Once fully assembled,
the green tire is dismantled from the tire building drum while the tire building drum
is in the collapsed state. It is then transferred to a curing mold for further processing,
where pressure and heat are applied to give the green tire its final shape.
[0003] Caution is to be exercised during dismantling the green tire from the tire
building drum for transferring the green tire to the curing mold. Operators handling the green tire need to exercise utmost care in removal of the green tire from the tire building drum to prevent any potential damage to the green tire.
BRIEF DESCRIPTION OF DRAWINGS
[0004] 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 features and components.
[0005] FIG. 1 is a cross-sectional view showing a working state of the tire
building drum, in accordance with an implementation of the present subject matter.
[0006] FIG. 2 is a cross-sectional view showing an expanded state of the tire
building drum, in accordance with an implementation of the present subject matter.
[0007] FIG. 3 is a cross-sectional view showing a collapsed state of the tire
building drum, in accordance with an implementation of the present subject matter.

DETAILED DESCRIPTION
[0008] The present subject matter relates to tire building drums.
[0009] As mentioned above, a tire building drum plays a crucial role in
producing green tires. Traditionally, a tire building drum has two distinct states, namely, a collapsed state and an expanded state, each with a corresponding distinct diameter, known as a collapsed diameter and an expanded diameter. The collapsed state and an expanded state each serve a specific purpose. In the collapsed state, carcass plies are carefully placed around the drum, forming a band with edges extending the drum's ends. When the drum is expanded outwards, the drum creates shoulders on both ends, securely anchoring the bead rings in place. This expansion also stretches the carcass plies with necessary tension, ensuring proper shaping of the tire. As will be apparent, the diameter of the tire building drum in the collapsed state, i.e., the collapsed diameter is smaller than its diameter in the expanded state, i.e., the expanded diameter. For further processing of the green tire, the tire building drum is brought to the collapsed state and the green tire is removed therefrom and transferred to a curing mold.
[0010] The traditional configuration of the tire building drum presents a
significant challenge during the removal process of green tire from the building drum. Typically, the collapsed diameter provides very minimal clearance between the green tire and the drum in their collapsed state. The clearance between the green tire and the drum may often be as small as 3mm. Since the removal operation is done manually by operators of the tire building drum, the limited space creates difficulties for the operator in easily maneuvering the green tire out of the drum for subsequent vulcanizing operations thereafter.
[0011] As a result, the operators are forced to exert substantial effort. This effort
sometimes leads to chipping, misshaping or disfigurement of the green tire, which later results in the formation of deformities in the finished product. Additionally, the application of force often involves a 30-degree body bend of the operator, to slide the green tire out of the drum. This process, at times, also leads to shoulder strain and potential back pain for the operator. This may affect the overall working capacity of the operator, resulting in loss of productivity.

[0012] Therefore, there is a need for a modified tire building drum that
facilitates a larger clearance between the green tire and the tire building drum at the
collapsed state and allows the operator to efficiently remove or dismantle the green
tire from the tire building drum for further processing, while also preventing the
potential damage that can be caused to the green tire during the dismantling process.
[0013] In accordance with the present subject matter, a tire building drum for
constructing a green tire is provided. In example implementations, the tire building drum of the present subject matter provides to solve the above-mentioned problems. In an example, the tire building drum of the present subject matter provides for efficiently removing or dismantling the green tire out from the tire building drum for further processing.
[0014] In accordance with an implementation, the tire building drum
comprising a central shaft, which extends coaxially along a rotation axis (X) of the tire building drum. A plurality of drum segments is mounted on this central shaft. Each of the drum segments is positioned coaxially to the central shaft and is spaced circumferentially about the central shaft such that an annular space exists between the central shaft and the plurality of drum segments. A cylindrical structure enclosing the annular space is positioned between the central shaft and the drum segments. The drum segments are collectively movable to allow the tire building drum to radially expand or collapse to positions corresponding to at least three distinct diameters of the tire building drum. The tire building drum further comprises a plurality of air vents integrated within the central shaft and operable to create pneumatic pressure in the annular space within the cylindrical structure to move the plurality of drum segments to the positions corresponding to each of the at least three distinct diameters.
[0015] As mentioned above, the traditional tire building drums suffers from the
inherent limitations with respect to their diameter range. The smallest diameter that the tire building drum can achieve through the inward movement of the drum segments is the collapsed diameter. Conversely, the expansion diameter represents the largest diameter that the tire building can achieve through expanding the drum segments outwards.

[0016] However, the existing collapsed diameter poses significant challenges
during the green tire construction process, particularly in the green tire removal stage. This stage necessitates collapsing the drum back to the collapsed diameter, after it has been expanded, for removing the green tire from the tire building drum for further processing. Unfortunately, the existing collapsed diameter often provides limited clearance between the green tire and the drum. This is because the existing collapsed diameter is very close to the actual diameter of the green tire itself.
[0017] The present invention overcomes the aforementioned limitations by
providing a diameter reduced than the above-explained collapsed diameter existing in the conventional tire building drums. Thus, in accordance with the present subject matter, the collapsed is the working diameter for the tire building drum. This working diameter falls between the expanded diameter and the reduced diameter herein described. The tire building material is applied onto the tire building drum at this working diameter. Subsequently, following the expansion stage, the tire building drum is moved to the reduced diameter to facilitate easy removal of the green tire. The reduced diameter ensures to provide the operator a larger clearance between the green tire and the tire building drum.
[0018] By enabling tire building drums to achieve the above-explained reduced
collapsed diameter, the invention as claimed significantly simplifies the process of the green tire dismantling for the operator. The increased clearance between the green tire and the tire building drum minimizes the need for the substantial manual efforts by the operator during the removal. The tire building drum of the present subject matter overcomes the limitations associated with the conventional tire building drums. Also, since no additional efforts are required by the operator in removing the green tire from the tire building drum, the potential tire deformities in the green tire that might arise due to improper unloading techniques can be reduced. Additionally, the physical issues faced by the operator in exerting the additional force in removing the green tire can be reduced, thus increasing the operational efficiency of the tire manufacturing process.

[0019] The above-mentioned implementations are further described herein with
reference to the accompanying figures. It should be noted that the description and figures relate to exemplary implementations 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.
[0020] FIG. 1 illustrates a schematic diagram of a tire building drum 100 of a
tire building process, in accordance with an implementation of the present subject matter. In an implementation, tire building drum 100 includes a central shaft 102 which extends coaxially along the rotation axis (X) and functions as a rotating member of the tire building drum 100. A plurality of drum segments 103 are mounted on this central shaft 102 and are positioned such that the drum segments 103 are coaxial to the central shaft 102. The drum segments 103 are spaced circumferentially about the central shaft 102 in such a way that an annular space is created between the central shaft 102 and the plurality of drum segments 103. A cylindrical structure 110 provided between the central shaft and the drum segments 103 serves to seal the annular space. The walls of the cylindrical structure are coaxial with the plurality of drum segments 103 and a first end 110a and a second end 110b of the cylindrical structure 110 are substantially perpendicular with respect to the rotation axis (X) of the central shaft. The drum segments 103 are collectively movable to allow the tire building drum 100 to radially expand or collapse to at least three distinct diameters. The tire building drum 100 further comprises a plurality of air vents, including a first vent 104a, a second vent 104b, and a third vent 104c, integrated within the central shaft 102. The plurality of air vents is operable for providing pneumatic pressure to move the drum segments 103 to positions corresponding to at least three distinct diameters.
[0021] The annular space within the cylindrical structure 110 placed between
the central shaft 102 and the drum segments 103 is an air-tight space. The annular

space comprises a first sealed end 107a and a second sealed end 107b collocated with the first end 110a and the second end 110b of cylindrical structure 110. The first sealed end 107a of the annular space is formed by a first slider 109a slidably mounted on the central shaft 102. The second sealed end 107b of the annular space comprises a second slider 109b. Both the first slider 109a and the second slider 109b are wedge-shaped. The first slider 109a includes two ends, specifically a distal end 109a-1 and a proximal end 109a-2, such that the distal end 109a-1 is further to the first piston 105a than the proximal end 109a-2. The first slider 109a engages with a stationary member 108 of the tire building drum 100 located external to the cylindrical structure 110 to facilitate the radial movement of the drum segments 103. A corresponding arrangement is mirrored on the opposite side with the second slider 109b. The stationary member 108 is also configured with two ends: an outer end 108-1 and an inner end 108-2, with the inner end 108-2 being proximal to the first piston 105a compared to the outer end 108-1. The stationary member 108 is provided with a wedge-shaped profile to complement the wedge-shaped sliders 109a and 109b, ensuring a seamless wedging action while also maintaining the airtight seal within the annular space during the expansion and collapse of the drum segments 103.
[0022] In an example, the first end 110a of the cylindrical structure 110 is
connected to the first slider 109a. This connection allows for the coordinated movement of the first slider 109a with the cylindrical structure 110, thereby facilitating the radial expansion or collapse of the drum segments 103. In another example, the connection between the first end 110a of the cylindrical structure 110 and the first slider 109a can be a threaded connection, which provides a secure and adjustable linkage between these components.
[0023] Similarly, the second end 110b of the cylindrical structure 110 is
connected to the second slider 109b. This connection ensures that the second slider 109b moves in tandem with the cylindrical structure 110, contributing to the radial expansion or collapse of the drum segments 103. In another example, the connection between the second end 110b of the cylindrical structure 110 and the second slider 109b can also be a threaded connection.

[0024] In operation, axial movement of the first slider 109a and the second
slider 109b occurs in tandem with the axial movement of the cylindrical structure 110, due to the pneumatic pressure provided by the air vents integrated within the central shaft 102. This coordinated movement effectively leverages a wedging action, leading to either the outward radial expansion or collapse of the drum segments 103 of the tire building drum 100. As will be apparent, the wedging action is initiated by the axial movement of the first slider 109a and the second slider 109b either towards the directional arrow A or towards the directional arrow B, which is induced by the pneumatic pressure supplied through the air vents integrated within the central shaft 102. As the first slider 109a and the second slider 109b move axially, their wedge-shaped profiles interact with corresponding wedge-shaped stationary member 108, located at either end of the annular space.
[0025] The distal end 109a-1 and the proximal end 109a-2 of the first slider
109a engage with the outer end 108-1 and inner end 108-2 of the stationary member 108. A similar arrangement is mirrored on the opposite side with the second slider 109b. The axial movement of the sliders 109a and 109b are towards the directional arrow B. This engagement creates a wedging force that is directed radially outward, causing the drum segments 103 to move away from the central shaft 102, thereby expanding the diameter of the tire building drum 100. Conversely, when the axial movement of the sliders 109a and 109b is reversed towards the directional arrow A, the drum segments 103 move radially inward, collapsing the diameter of the tire building drum 100.
[0026] In accordance with an implementation of the present subject matter, the
tire building drum 100 includes at least a first piston 105a and a second piston 105b mounted on the central shaft 102 inside the cylindrical structure 110. The first piston 105a is axially movable with respect to the central shaft 102 on application of the pneumatic pressure from the air vents integrated within the central shaft 102 and the second piston 105b is in the fixed configuration with respect to the central shaft 102. The first piston 105a and the second piston 105b partition the airtight annular space inside the cylindrical structure 110 into at least three individual pneumatic chambers 106a, 106b, 106c.

[0027] A first pneumatic chamber 106a of the three pneumatic chambers is
positioned between the first piston 105a and the first end 110a of the cylindrical
structure 110. The first pneumatic chamber 106a is configured to receive
compressed air from the first air vent 104a integrated within the central shaft 102.
[0028] A second pneumatic chamber 106b of the three pneumatic chambers is
positioned between the first piston 105a and the second piston 105b inside the cylindrical structure 110. The second pneumatic chamber 106b is configured to receive compressed air from the second air vent 104b integrated within the central shaft 102.
[0029] A third pneumatic chamber 106c of the three pneumatic chambers is
positioned between the second piston 105b and the second end 110b of the cylindrical structure 110. The third pneumatic chamber 106c is configured to receive compressed air from the third air vent 104c integrated within the central shaft 102.
[0030] In order to facilitate a comprehensive understanding of the operational
functionality of the present tire building drum, a sequence of exemplary diameter transitions achievable through the actuation of the pneumatic chambers is described herein. This sequence outlines the movement of the tire building drum 100 from a collapsed or rest state, to a working state, followed by an expansion state, and finally back to the collapsed state.
[0031] As mentioned above, the cross-sectional view of the tire building drum
100 shown in FIG. 1 corresponds to a working state of the tire building drum 100, in accordance with an implementation of the present subject matter.
[0032] In an example implementation, the tire building drum 100 can transition
to the working state from the collapsed state. The working state corresponds to the position of the tire building drum 100 at which the application of the tire building components, such as carcass plies onto the tire building drum 100 takes place to form the green tire. For the tire building drum 100 to achieve the working diameter, or, in other words, for the tire building drum 100 to move to a position corresponding to the working diameter from the collapsed state, compressed air is introduced into the two pneumatic chambers simultaneously.

[0033] Firstly, compressed air is introduced to the third chamber 106c through
the third air vent 104c, integrated within the central shaft 102. This air pressurizes
the third chamber 106c. Simultaneously, compressed air is also introduced into the
second chamber 106b through the second air vent 104b integrated within the central
shaft 102. This air pressurizes the second chamber 106b, applying a force on the
second end 110b of the cylindrical structure 110 that in turn causes the first piston
105a to move axially. The introduction of the compressed air to the second
pneumatic chamber 106b and the third pneumatic chamber 106c depressurizes the
first pneumatic chamber 106a. This causes an axial movement of the cylindrical
structure 110 together with both the first slider 109a and the second slider 109b
along the rotation axis (X), in the direction denoted by the directional arrow B, such
that the first piston 105a is at its closest position with respect to the proximal end
109a-2 of the first slider 109a, along the axial length it can traverse. The first slider
109a, second slider 109b and the cylindrical structure 110 undergo a displacement
in the same direction simultaneously. The coordinated axial movement of the
cylindrical structure 110, together with the first slider 109a and the second slider
109b induces the outward expansion of the drum segments 103 by utilizing the
above-described wedging action of the first slider 109a and the second slider 109b.
[0034] As will be apparent to one skilled in the art, the outward expansion of
the drum segments 103 causes the diameter of the tire building drum 100 to increase compared to the diameter of the tire building drum 100 in the collapsed state. This increased diameter corresponds to the working diameter of the tire building drum 100, or, in other words, the diameter of the tire building drum 100 in the working state. In an example, the working diameter of the tire building drum 100 lies in a range of 246 mm - 249 mm.
[0035] FIG. 2 is a cross-sectional view showing an expanded state of the tire
building drum, in accordance with an implementation of the present subject matter. Reference is made to FIG. 2 to explain the transition of the tire building drum 100 to an expanded state from the working state, in accordance with an implementation of the present subject matter.

[0036] The expanded diameter corresponds to a position of the tire building
drum 100 when the applied material is uniformly stretched to the predefined
dimensions and to create the shoulders regions on either side of the tire building
drum 100. As will be apparent to one skilled in the art, the predefined dimensions
depend on the type of green tire being constructed in the tire building drum 100.
[0037] To achieve the expanded diameter, compressed air is introduced only to
the third chamber 106c through the third air vent 104c. The air pressurizes the third chamber 106c, applying a force on the first piston 105a that compels it to move axially. The introduction of the compressed air only to the third pneumatic chamber 106c depressurizes the first 106a and the second 106b pneumatic chambers. This causes an axial movement of the cylindrical structure 110 together with the first slider 109a and the second slider 109b further along the rotation axis (X), as denoted by direction arrow B, such that the first piston 105a is closest to the proximal end 109a-2 of the first slider 109a and also closest to the second piston 105b on the opposite side. The coordinated axial movement of the cylindrical structure 110 together with the first slider 109a and the second slider 109b in the direction of the arrow B induces a maximum outward expansion of the drum segments 103 by utilizing the above-described wedging mechanism at the first slider 109a and the second slider 109b.
[0038] As will be apparent to one skilled in the art, the outward expansion of
the drum segments 103 causes the diameter of the tire building drum 100 to further increase compared to the diameter of the tire building drum 100 in the working state. This increased diameter corresponds to the expanded diameter of the tire building drum 100, or, in other words, the diameter of the tire building drum 100 in the expanded state. In an example, the expanded diameter of the tire building drum 100 lies in a range of 270 mm to 274 mm.
[0039] FIG. 3 illustrates a tire building drum 100 in a collapsed diameter, in
accordance with an implementation of the present subject matter. The collapsed diameter corresponds to a position of the tire building drum 100 when the green tyre is removed from the tire building drum 100 for further processing. As mentioned above, the collapsed diameter is smaller than the working diameter of

the tire building drum 100. To achieve the working diameter, compressed air is introduced into the two pneumatic chambers simultaneously.
[0040] Firstly, compressed air is introduced to the first chamber 106a through
the first air vent 104a, integrated within the central shaft 102. This air pressurizes the first chamber 106a. Simultaneously, compressed air is also introduced into the second chamber 106b through the second air vent 104b, integrated within the central shaft 102. This air pressurizes the second chamber 106b, applying a force on the first piston 105a that compels it to considerably move axially, as denoted by the directional arrow A. The introduction of the compressed air into the first chamber 106a and the second chamber 106b cause an axial movement of the cylindrical structure 110 together with the first slider 109a and the second slider 109b in the direction of arrow A, such that the first piston 105a is slightly away from the previous position when the first piston 105a was closest to the proximal end 109a-2 of the first sliding member 109a, and the second piston 105b is at its closest position with respect to the second end 110b of the cylindrical structure 110 on the opposite side of the tire building drum 100. The coordinated axial movement of these portions strategically induces an inward collapse of the drum segments 103 by utilizing the above-mentioned wedging mechanism at the first slider 109a and the second slider 109b.
[0041] As will be apparent to one skilled in the art, the inward collapse of the
drum segments 103 causes the diameter of the tire building drum 100 to decrease compared to the diameter of the tire building drum 100 in the expanded state. This decreased diameter corresponds to the collapsed diameter of the tire building drum 100, or, in other words, the diameter of the tire building drum 100 in the collapsed state. In an example, the collapsed diameter of the tire building drum 100 is substantially in a range of 238 mm to 241 mm.
[0042] The present subject matter thus provides for a tire building drum having
at least three diameters. The three diameters of the tire building drum allow for the smaller collapsed diameter compared to a working diameter of the tire building drum. This provides a larger clearance between the tire building drum and the green tire to facilitate the process of efficiently removing the green tire by the operator.

Also, since no additional manual effort is required from the operator in dismantling the green tire from the tire building drum, the possibility of deformation in the green tire is greatly reduced. Additionally, the operator’s physical issues arising from the tedious process of removing the green tires from the traditional tire building drums are also reduced, thus increasing the efficiency of the operator.
[0043] In example implementations, the collapsed diameter as disclosed in the
present invention, facilitates the efficient dismantling or removal of the green tire by offering a clearance range of 6 mm to 10 mm between the green tire and the tire building drum. This ample clearance significantly minimizes the risk of potential damage to the green tire during the dismantling process and simplifies the process for the operator.
[0044] 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 building drum (100) for constructing a green tire, the tire building
drum (100) comprising:
a central shaft (102) extending coaxially to a rotation axis (X);
a plurality of drum segments (103) mounted on the central shaft (102), the plurality of drum segments (103) being coaxial to the central shaft (102) and spaced circumferentially about the central shaft (102) such that an annular space exists between the central shaft (102) and the plurality of drum segments (103),
wherein a cylindrical structure (110) is positioned between the central shaft (102) and the plurality of drum segments (103), enclosing the annular space;
wherein each of the plurality of drum segments (103) is movable to allow the tire building drum (100) to radially expand or collapse to positions corresponding to at least three distinct diameters of the tire building drum (100); and
a plurality of air vents (104a, 104b, 104c) integrated within the central shaft (102) and operable to create pneumatic pressure in the annular space within the cylindrical structure (110) to move the plurality of drum segments (103) to the positions corresponding to each of the at least three distinct diameters.
2. The tire building drum (100) as claimed in claim 1, comprising a first piston (105a) and a second piston (105b) mounted on the central shaft (102) for partitioning the annular space within the cylindrical structure (110) into at least a first pneumatic chamber (106a), a second pneumatic chamber (106b) and a third pneumatic chamber (106c), wherein the first piston (105a) is axially movable with respect to the central shaft (102) on application of pneumatic pressure and the second piston (105b) is in a fixed configuration.
3. The tire building drum (100) as claimed in claim 2, wherein the first pneumatic chamber (106a) is positioned between the first piston (105a) and a first end (110a) of the cylindrical structure (110), and configured to receive

compressed air from a first air vent (104a) of the plurality of air vents, wherein the first end (110a) of the cylindrical structure (110) is connected to a first slider (109a) slidably mounted on the central shaft (102), wherein the first slider (109a) is wedge-shaped, and wherein the axial movement of the first slider (109a) allows for the plurality of drum segments (103) to radially expand or collapse.
4. The tire building drum (100) as claimed in claim 2, wherein the second pneumatic chamber (106b) is positioned between the first piston (105a) and the second piston (105b) and is configured to receive compressed air from a second air vent (104b) of the plurality of air vents.
5. The tire building drum (100) as claimed in claim 2, wherein the third pneumatic chamber (106c) is positioned between the second piston (105b) and a second end (110b) of the cylindrical structure 110, and configured to receive compressed air from a third air vent (104c) of the plurality of air vents, wherein the second end (110b) of the cylindrical structure (110) is connected to a second slider (109b) slidably mounted on the central shaft (102), wherein the second slider (109b) is wedge-shaped, and wherein the axial movement of the second slider (109b) allows for the plurality of drum segments (103) to radially expand or collapse.
6. The tire building drum (100) as claimed in claim 2, wherein the introduction of the pneumatic pressure into at least one of the first pneumatic chamber (106a), second pneumatic chamber (106b) and third pneumatic chamber (106c) is to cause the axial movement of the first piston (105a) to move the plurality of drum segments (103) to a position corresponding to one of the at least three distinct diameters of the tire building drum (100), wherein the at least three distinct diameters of the tire building drum (100) comprises:
a working diameter corresponding to a position of the tire building drum (100) where the tire building components are applied onto the tire building drum (100) for constructing the green tire;

an expansion diameter corresponding to the position of the tire building drum (100) where the green tire is uniformly stretched to a predefined dimension; and
a collapse diameter corresponding to the position of the tire building drum (100) where the green tire is removed from the tire building drum (100), wherein the collapse diameter is smaller than the predefined diameter.
7. The tire building drum (100) as claimed in claim 6, wherein
the expansion diameter is achieved by introducing compressed air into the third pneumatic chamber (106c) through a third air vent (104c) of the plurality of air vents;
the working diameter is achieved by introducing compressed air into the second pneumatic chamber (106b) and the third pneumatic chamber (106c) via a second air vent (104b) and the third air vent (104c) of the plurality of air vents; and
the collapsed diameter is achieved by introducing compressed air into the first pneumatic chamber (106a) and the second pneumatic chamber (106b) via the first air vent (104a) and a second air vent (104b) of the plurality of air vents.
8. The tire building drum (100) as claimed in claim 6, wherein the collapsed diameter is substantially in a range of 238 mm to 241 mm, the working diameter is substantially within a range of 246 mm to 249 mm, and the expanded diameter is substantially within a range of 270 mm to 274 mm.
9. The tire building drum (100) as claimed in claim 6, wherein the collapsed diameter provides a clearance between the green tire and the tire building drum (100) within a range of 6 mm to 10 mm to facilitate the easy removal of the green tire from the tire building drum (100).