WO2020044126A1

WO2020044126A1 - Tire building method and apparatus

Info

Publication number: WO2020044126A1
Application number: PCT/IB2019/050220
Authority: WO
Inventors: Kumar SANTHANAM; Antony Bosco RABERO DYRIAM
Original assignee: Larsen & Toubro Limited
Priority date: 2018-08-31
Filing date: 2019-01-11
Publication date: 2020-03-05

Abstract

The present invention relates to a tire building apparatus (100) comprising an inflatable cylindrical carcass drum (101), a bead positioning mechanism and a pair of collapsible pusher assemblies (102). The inflatable cylindrical carcass drum (101) is mounted on a main shaft and comprises a carcass supporting body and a pair of bead setter assembly. The main shaft includes a threaded shaft arrangement (104), a pair of internally threaded nuts (108) and a pair of slip assist mechanisms (109). The slip assist mechanism is operably connected to each of the bead setter assembly and operates such that the engagement and disengagement of the slip assist mechanism alternatively connects the threaded shaft with the nut with a purpose of transmitting or slipping the rotary motion of the slip assist nut to the bead setter assembly.

Description

TIRE BUILDING METHOD AND APPARATUS

FIELD OF INVENTION:

The present invention generally relates to a tire building method and apparatus. More particularly, the present invention relates to a tire building method and apparatus wherein a collapsible pusher assembly and the bead setter assembly on each side of a carcass drum are operably connected to the shaft of the carcass drum.

BACKGROUND OF THE INVENTION:

In the existing system of tire building apparatus, the pusher assemblies are mounted to carcass drive (right side) and on Breaker and Tread drum drive (B&T drive) (left side) assemblies. After pre-shaping of ply materials and bladder inflation, the pusher rings in the pusher assembly extend to reach carcass drum to roll the inflated bladder over the pre shaped carcass to form complete turn up. These pusher rings are extended with the help of air cylinders.

However, there are certain drawbacks associated with the existing tire building apparatus. Firstly, the pusher assembly on either side of carcass drum is placed at an un-equal distance. The pusher assembly on the left side (B&T side) needs to extend for up to 3 meters to reach the carcass drum. Secondly the shaft on which the pusher assembly is mounted passes through B&T drum to extend thereby causing a chance to disturb the B&T drum alignment and also time consuming to extend up to the distance and then retract. Thirdly, in most of the prior arts, the pusher rings of the pusher assembly comprise a set of fingers or rollers which roll over the pre-shaped carcass to turn up the carcass material over the beads. In this process, the fingers and rollers cause impression on the rubber material of the tire. Also, the roller s/fingers are positioned at certain intervals/gaps which do not always provide a 360 degree all around tight turn up.

Accordingly, there is a need for an improved tire building apparatus and method thereof which overcomes the above-mentioned disadvantages and is also simple, reliable and cost effective.

OBJECTS OF THE INVENTION:

One object of the present invention is to reduce time lag during bladder pusher operation due to extended length of B&T side pusher assembly and to eliminate alignment disturbance on the B&T drum assembly.

Another object of the present invention is to provide 360° complete all around tight turn up of overhang carcass portion onto the inflated center carcass portion.

These and other objects as well as advantages will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.

SUMMARY OF THE INVENTION:

In accordance with the purposes of the invention, the present invention as embodied and broadly described herein, provides a tire building apparatus comprising an inflatable cylindrical carcass drum, a bead positioning assembly and a pair of collapsible pusher assemblies. Each of the collapsible pusher assembly from said pair is located on either side of the cylindrical carcass drum. The inflatable cylindrical carcass drum is mounted on a main shaft and comprises a carcass supporting body and a pair of bead setter assemblies. The main shaft includes a threaded shaft arrangement, said threaded shaft arrangement having an externally threaded shaft, a pair of internally threaded nuts and a pair of slip assist mechanisms. In one embodiment, said pair of internally threaded nuts are replacable with a further pair of slip assist mechanisms one on either sides of the externally threaded shaft.

Each of the internally threaded nut and slip assist mechanism from said pair is located on either side of the cylindrical carcass drum and engageable with the externally threaded shaft. Each slip assist mechanism comprises a slip nut and means to engage and disengage the slip nut from the externally threaded shaft.

The carcass supporting body is adapted to receive ply materials to form a cylindrical carcass. The beads are positioned by the bead positioning assembly.

The bead setter assembly is placed one on each side of said carcass supporting body. Each bead setter assembly comprises an inflatable bladder which is configured to inflate and partially fold the overhang portions of the carcass. In other words, on inflation of the bladders, the overhang portions are partially turned up and rest on the inflated bladders. The bead setter assembly further comprises bead holding mechanism such as bead hold levers and bead locking mechanism such as bead lock fingers. Each of the bead setter assembly is operably connected to the slip assist mechanism located on the same side and operates such that the engagement and disengagement of the slip assist mechanism alternatively connects the threaded shaft with the slip assist nut with a purpose of transmitting or slipping the rotary motion of the slip assist nut to bead setter assembly. In other words, de-activation of the slip assist mechanism engages the threaded shaft with the slip assist nut to allow the linear movement of the bead setter assembly along the shaft and the activation of the slip assist mechanism disengages the threaded shaft with the slip assist nut to stop the linear movement of the bead setter assembly along the shaft.

The bead positioning assembly is located externally to the carcass drum and is adapted to place a first bead and a second bead on said cylindrical carcass drum such that a portion of the carcass between the first bead and the second bead is defined as a center carcass portion and portions of carcass on either side of the center portions are overhang portions.

Each of the collapsible pusher assemblies is mounted on the main shaft at a predetermined distance from ends of said cylindrical carcass drum. Each collapsible pusher assembly is operably connected to the internally threaded nut located on the same side such that the rotation of the internally threaded nut leads to the linear movement of the collapsible pusher assembly along the shaft. The collapsible pusher assembly further includes a pusher ring having pusher arms which are adapted to expand and push the inflated bladder which completely folds the overhang carcass portion onto the inflated center carcass portion to wrap the beads for a complete turn up. In other words, the overhang carcass portions are now wrapped over the beads for a complete turn up.

The present invention as embodied and broadly described herein, further provides a tire building method. The method comprises receiving materials to form a cylindrical carcass on a cylindrical carcass drum. The method further comprises placing a first bead and a second bead on said cylindrical carcass drum such that a portion of the carcass between the first bead and the second bead is defined as a center carcass portion and portions of the carcass on either side of the center carcass portion are overhang carcass portions. The method further comprises inflating the cylindrical carcass drum to inflate the center carcass portion. This is generally called as a pre-shaping operation. During this operation, the slip assist mechanism is not activated resulting into linear movement of both the bead setter assembly and collapsible pusher assembly towards the carcass drum. At the end of the pre-shaping operation, the bladders of the bead setter assembly underly inner surfaces of said overhang portion of the carcass. Thereafter, the method comprises inflating the bladders of the bead setter assembly and expanding the pusher arms of the collapsible pusher assemblies. The inflation of bladders partially folds the overhang portions of the carcass drum to turn up over the first and second beads.

Thereafter, the method comprises activation of the slip assist mechanism. The activation of slip assist mechanism stops the linear movement of the bead setter assembly along the shaft. As a result, only the collapsible pusher assembly moves towards the carcass drum and the expanded pusher arms pushes the inflated bladders to roll over the overhang portions tightly onto the inflated center carcass portions. The overhang portions are now wrapped over the beads for a complete turn up.

These and other aspects as well as advantages will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims.

BRIEF DESCRIPTION OF DRAWINGS

To further clarify advantages and aspects of the invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings, which are listed below for quick reference.

Figure 1 (a) illustrates a sectional view of the tire building apparatus of the present invention prior to a pre-shaped condition. Figure 1 (b) illustrates an expanded view of portion A of the tire building apparatus in Figure 1(a).

Figure 2 illustrates a sectional view of the tire building apparatus of the present invention during a pre-shaped condition.

Figure 3 illustrates a sectional view of the tire building apparatus of the present invention during a bladder inflated condition.

Figure 4 illustrates a sectional view of the tire building apparatus of the present invention during a bladder turn-up operation.

Figure 5 illustrates a tire building method in accordance with the embodiment of the present invention.

Figure 6 illustrates the isometric view of a section of the pusher assembly in accordance with the embodiment of the present invention.

The person ordinary skill in the art will appreciate that elements in the drawings are illustrated for simplicity and may not have been necessarily drawn to scale. For example, the dimensions of some of the elements in the drawings may be exaggerated relative to other elements to help to improve understanding of aspects of the invention. Furthermore, the one or more elements may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

DETAILED DESCRIPTION

It should be understood at the outset that although illustrative implementations of the embodiments of the present disclosure are illustrated below, the present invention may be implemented using any number of techniques, whether currently known or in existence. The present disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary design and implementation illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents.

The term“some” as used herein is defined as“none, or one, or more than one, or all”. Accordingly, the terms“none,”“one,”“more than one,”“more than one, but not all” or“all” would all fall under the definition of “some.” The term“some embodiments” may refer to no embodiments or to one embodiment or to several embodiments or to all embodiments. Accordingly, the term“some embodiments” is defined as meaning “no embodiment, or one embodiment, or more than one embodiment, or all embodiments.”

The terminology and structure employed herein is for describing, teaching and illuminating some embodiments and their specific features and elements and does not limit, restrict or reduce the spirit and scope of the claims or their equivalents.

More specifically, any terms used herein such as but not limited to “includes,” “comprises,” “has,” “consists,” and grammatical variants thereof do NOT specify an exact limitation or restriction and certainly do NOT exclude the possible addition of one or more features or elements, unless otherwise stated, and furthermore must NOT be taken to exclude the possible removal of one or more of the listed features and elements, unless otherwise stated with the limiting language “MUST comprise” or“NEEDS TO include.”

Whether or not a certain feature or element was limited to being used only once, either way it may still be referred to as“one or more features” or“one or more elements” or“at least one feature” or“at least one element.” Furthermore, the use of the terms“one or more” or“at least one” feature or element do NOT preclude there being none of that feature or element, unless otherwise specified by limiting language such as“there NEEDS to be one or more . . .” or“one or more element is REQUIRED.”

Unless otherwise defined, all terms, and especially any technical and/or scientific terms, used herein may be taken to have the same meaning as commonly understood by one having an ordinary skill in the art.

Reference is made herein to some“embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the attached claims. Some embodiments have been described for the purpose of illuminating one or more of the potential ways in which the specific features and/or elements of the attached claims fulfill the requirements of uniqueness, utility and non-obviousness.

Use of the phrases and/or terms such as but not limited to “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,”“an embodiment,”“multiple embodiments,”“some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or variants thereof do NOT necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or alternatively in the context of more than one embodiment, or further alternatively in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.

Any particular and all details set forth herein are used in the context of some embodiments and therefore should NOT be necessarily taken as limiting factors to the attached claims. The attached claims and their legal equivalents can be realized in the context of embodiments other than the ones used as illustrative examples in the description below.

Figure 1 (a) illustrates a sectional view of the tire building apparatus 100 in accordance with an embodiment of the present invention. Figure 1 (b) illustrates an expanded view of portion A of the tire building apparatus in Figure 1(a).

The tire building apparatus 100 comprises an inflatable cylindrical carcass drum 101, a bead positioning assembly ( not shown) and a pair of collapsible pusher assemblies 102 located on either side of said carcass drum 101. The inflatable cylindrical carcass drum 101 is mounted on a main shaft 103. The main shaft 103 includes a threaded shaft arrangement 104 located inside the main shaft 103. The inflatable cylindrical carcass drum 101 comprises a pair of bead setter assembly 105 and a carcass supporting body 106. Each of the bead setter assembly 105 from said pair is located on either side of the cylindrical carcass drum 101. The carcass supporting body 106 is adapted to receive carcass material to form a cylindrical carcass. Describing the process with more particularity, the carcass building operation consists in removing a series of carcass plies from suitable servicing equipment (not shown) located near the carcass supporting body 106, and wrapping the plies, preferably, one at a time around the supporting body 106. Each of these plies is composed of materials already known in the art including processed rubber material and other material known to a person skilled in the art.

The threaded shaft arrangement 104 includes an externally threaded shaft l04a, a pair of internally threaded nuts 108 and a pair of slip assists mechanisms 109. Each of the internally threaded nuts 108 from said pair is located on either side of cylindrical carcass drum 101 and is operably connected to the collapsible pusher assembly 102 located on the same side. Each of the slip assist mechanisms 109 from said pair is located on either side of the carcass drum 101 and is operably connected to the bead setter assembly 105 located on the same side. The slip assist mechanism 109 comprises a slip assist nut engageable with the threaded shaft and means to engage and disengage the slip assist nut from said externally threaded shaft. The nuts are axially movable along the threaded shaft on the rotation of the externally threaded shaft. Means to engage and disengage the nuts comprises, being not limited to, springs, clutch plates and the likes.

It is to be understood that different constructions of externally threaded shaft are possible. Such constructions have been discussed in detail in the prior art applications such as US 2015/0239191 Al, EP 2 217 433 Bl, US8881785 B2. It is to be further understood that constructions of internally threaded nut and the slip assist mechanism may vary in accordance with construction of the externally threaded shaft as will be obvious to a person ordinarily skilled in the art.

The bead setter assembly 105 is located one on each side of said carcass supporting body 106. Each of the bead setter assembly 105 comprises an inflatable bladder 110, a bead holding mechanism 111 and a bead locking mechanism 112. The bead holding mechanism 111 is adapted to locate the beads at an exact position. During pre-shaping operation, the beads tend to move from its position. The bead locking mechanism 112 is adapted to avoid this movement. The inflatable bladders 110 is adapted to inflate and partially fold overhang portions (discussed below) of the cylindrical carcass which turns up over the first and second beads. The partially turned up overhang carcass portions rests on the inflated bladders.

Each of the bead setter assembly 105 is operably connected to the slip assist mechanism 109. Activation of the slip assist mechanism 109 leads to disengagement of the externally threaded shaft l04a with the slip assist nut such that the rotational movement of the externally threaded shaft l04a is not transmitted to the slip- assist nut. In other words, activation of slip assist mechanism locks the movement of the slip assist nut which, in turn, locks the linear movement of the bead setter assembly 105 along the shaft 103. Similarly, deactivation of slip-assist mechanism 109 leads to engagement of the externally threaded shaft l04a with the slip assist nut such that the rotational movement of the externally threaded shaft l04a is transmitted to the slip assist nut which in turn leads to the linear movement of the bead setter assembly 105 along the shaft.

The bead positioning assembly ( not shown) is located externally to the cylindrical carcass drum 101 and is adapted to place a first bead H8a and a second bead 118b on cylindrical carcass such that a portion of the carcass between the first bead 118a and the second bead 118b is defined as a center carcass portion and portions of the carcass on the either side of the center carcass portion are overhang portions. The inflatable bladders 110 of bead setter assembly 105 are adapted to inflate and partially fold the overhang portions of said cylindrical carcass over the first bead 118a and second bead 118b. The inflation of the centre carcass portion is already known in the art and is performed prior to the inflation of the overhang carcass portion.

The collapsible pusher assemblies 102 are mounted on the main shaft 103 and are located one on each side of said cylindrical carcass drum 101 at a pre-determined distance from ends of the cylindrical carcass drum 101. The pre-determined distance of each collapsible pusher assembly 102 from the end of the carcass drum 101 is adjustable. As discussed above, the collapsible pusher assembly 102 is operably connected to the externally threaded shaft 104a by means of the internally threaded nuts 108 such that rotation of externally threaded shaft 104a leads to the linear movement of the collapsible pusher assembly along the shaft 103. Each of the collapsible pusher assembly 102 includes a pusher ring 113 having pusher arms which are adapted to expand and push the inflated bladder which completely folds the overhang carcass portion onto the inflated center carcass portion to wrap the beads for a complete turn up. In other words, the overhang carcass portions are now wrapped over the beads for a complete turn up.

In one embodiment, the pusher ring comprises a central support member 114 such as a disc shaped structure and a plurality of radially extending collapsible arms 115 having a first end pivotally connected to the disc shaped structure and a second free end wherein the first ends are spaced along the circumference of said disc shaped structure 114. The second free end of each of the plurality of arms comprises a circular profile or any other related profile in order to maintain smooth contact with the bladder, said profile comprises a rolling surface, a first side surface and a second side surface such that, on expansion of said arms, a first side surface of one roller arm abuts a second side surface of adjacent arm. The expansion and collapse movement of said pusher mechanism is achieved by spring, rubber ring, external actuators etc. In the collapsed state, the arms of the pusher ring partially or completely support the bladder ends of the said bead setter assembly on the respective sides of the said carcass supporting body. In the collapsed state, the alternate collapsible pusher arm moves radially inwards more than the adjacent arms thereby forming a dual circumference structure.

In another embodiment, the pusher ring comprises a set of levers with one end of each lever connected to each of the collapsible arms and operates radially. The levers provide additional control for expansion of collapsible arms.

It is to be understood that expansion and collapse movement of pusher arms is achieved by means selected from a group consisting of spring, rubber ring and external actuators such as pneumatic actuators. Said examples should not in any way be construed as limiting and includes other actuators known to a person ordinarily skilled in the art.

Figure 2 illustrates a sectional view of the tire building apparatus 100 of the present invention during a pre-shaped condition.

As shown in the Figure 2, during the pre-shaped condition, the inflatable cylindrical carcass drum 101 is inflated by methods known in the art to inflate the center carcass portion 116. Also, during the pre-shaped condition, the slip assist mechanisms 109 are deactivated and both the bead setter assemblies 105 and collapsible pusher assemblies 102 moves a pre-determined distance towards the cylindrical carcass drum 101. Owing to such movement, the bladders of the bead setter assemblies are positioned in cylindrical cavities of the overhang carcass portions. In other words, the overhang carcass portions rests on the deflated bladders.

Figure 3 illustrates a sectional view of the tire building apparatus 100 of the present invention during a bladder inflated condition.

As shown, during the bladder inflation condition, compressed air is passed in the bladders of the bead setter assembly 105 to inflate and partially fold the overhang portions of the cylindrical carcass over the first bead 118a and the second bead 118b. The overhang portions 117 rests on the inflated bladders. During bladder inflated condition, the collapsible arms 115 of the pusher rings 113 are also expanded.

Figure 4 illustrates a sectional view of the tire building apparatus of the present invention during a bladder tum-up operation.

During the bladder turn up operation, the slip mechanisms 109 are activated. Activation of slip assist mechanisms 109 lock the movement of the bead setter assemblies 105 and allow the movement of the collapsible pusher assemblies 102. Therefore, the collapsible pusher assemblies 102 moves towards the cylindrical carcass drum 101 and expanded pusher arms 115 pushes the inflated bladders which completely folds the overhang carcass portion onto the inflated center carcass portion to wrap the first bead 118a and second bead 118b for a complete turn up. In other words, the overhang carcass portions are now wrapped over the beads for a complete turn up. Figure 5 illustrates a tire building method in accordance with the embodiment of the present invention.

At step 501, the method comprises receiving materials on a cylindrical carcass drum to form a cylindrical carcass. Describing the process with more particularity, the carcass building operation consists in removing a series of carcass plies from suitable servicing equipment (not shown) located near the carcass drum 101, and wrapping the plies one at a time around the carcass drum 101. Each of these plies is composed of materials already known in the art.

At step 502, the method comprises placing a first bead 118a and a second bead 118b on the cylindrical carcass such that a portion of the carcass between the first bead H8a and the second bead H8b is defined as a center carcass portion 116 and portions of the carcass on either side of the center portion are overhang carcass portions 117. The first bead 118a and second bead 118b are placed on the cylindrical carcass drum 101 by means of a bead positioning assembly located externally to said cylindrical carcass drum 101.

At step 503, the method comprises inflating the center carcass portion 116 of said cylindrical carcass. During this operation, the slip assist mechanisms are in a deactivated state such that both the bead setter assemblies 105 and collapsible pusher assemblies 102 on either side of the cylindrical carcass drum 101 moves a pre determined distance towards the cylindrical carcass drum 101. Movement of the bead setter assemblies causes the bladders to be positioned in cylindrical cavities of said overhang carcass portions 117. In other words, the overhang carcass portions rests on the deflated bladders. At step 504, compressed air is filled in the bladders 110 of the bead setter assemblies 105 such that the overhang carcass portions partially fold and turn up over the first 118a and the second beads 118b. At this step, the method also comprises expanding the pusher arms of the collapsible pusher assemblies 102.

At step 505, the method comprises activating the slip assist mechanisms 109. Activation of the slip assist mechanisms 109 locks the movement of the bead setter assemblies 105. In other words, only the collapsible pusher assemblies 102 moves towards the cylindrical carcass drum 101 and the expanded pusher arms 115 pushes the inflated bladders 110 which completely fold the overhang carcass portion onto the inflated center carcass portion to wrap the beads for a complete turn up. In other words, the overhang carcass portions are now wrapped over the beads for a complete turn up.

As illustrated, the collapsible pusher assembly comprises a disc shaped structure 114 and a plurality of radially extending collapsible arms 115 having a first end 119 pivotally connected to said disc shaped structure 114 and a second free end 120 wherein the first ends 119 are spaced along the circumference of said disc shaped structure 114. The second free end 120 of each of the plurality of arms comprises a circular profile or any other related profile in order to maintain smooth contact with the bladder, said profile having a rolling surface 121, a first side surface 122 and a second side surface 123 such that, on expansion of said arms, a first side surface 122 of one arm abuts a second side surface 123 of adjacent arm. The expansion and collapse movement of said pusher mechanism is achieved by spring, rubber ring, external actuators etc. In the collapsed state, the arms of the pusher ring partially or completely support the bladder ends of the said bead setter assembly on the respective sides of the said carcass supporting body.

While certain present preferred embodiments of the invention have been illustrated and described herein, it is to be understood that the invention is not limited thereto. Clearly, the invention may be otherwise variously embodied, and practiced within the scope of the following claims.

Claims

1. A tire building apparatus comprising:

- an inflatable cylindrical carcass drum comprising a carcass supporting body and a pair of bead setter assemblies mounted on a main shaft, said carcass supporting body adapted to receive carcass materials to form a cylindrical carcass;

- said main shaft including a threaded shaft arrangement having an externally threaded shaft, a pair of internally threaded nuts and a pair of slip assist mechanisms wherein each of the internally threaded nuts and slip assist mechanisms is located on either side of the carcass drum and engageable with the externally threaded shaft;

- a bead positioning assembly located externally to said carcass drum and adapted to position a first bead and a second bead on the cylindrical carcass drum such that a portion of the cylindrical carcass between the first bead and the second bead is defined as a center carcass portion and portions of the carcass on either side of the center portion are overhang portions;

- the bead setter assemblies placed one on each side of said carcass supporting body, each bead setter assembly comprising an inflatable bladder wherein said inflatable bladders are inflated to partially fold the overhang carcass portions over the first and second beads;

- a pair of collapsible pusher assemblies mounted on said shaft, each collapsible pusher assembly mounted at a predetermined distance from ends of said cylindrical carcass drum, each collapsible pusher assembly comprising a pusher ring having pusher arms adapted to expand and push the inflated bladders which completely folds the overhang carcass portion onto the inflated center carcass portion to wrap the first and second beads for a complete turn up;

- wherein the collapsible pusher assembly and the bead setter assembly on each side of the carcass drum are operably connected to the externally threaded shaft of the carcass drum; and

- wherein the slip assist mechanism is operably connected to bead setter assembly such that activation or de-activation of the slip assist mechanism alternatively disengages or engages the threaded shaft with a slip-assist nut with a purpose of slipping or transmitting the rotary motion of the slip assist nut to the bead setter assembly.

2. The tire building apparatus as claimed in claim 1, wherein the collapsible pusher assembly on each side of the carcass drum is connected to the internally threaded nut on the same side of the carcass drum and the bead setter assembly on each side of the carcass drum is connected to the slip assist mechanism on the same side of the carcass drum.

3. The tire building apparatus as claimed in claim 1, wherein the de-activation of the slip assist mechanism engages the threaded shaft with the slip assist nut to allow the linear movement of the bead setter assembly along the shaft and the activation of the slip assist mechanism disengages the threaded shaft with the slip assist nut to stop the linear movement of the bead setter assembly along the shaft.

4. The tire building apparatus as claimed in claim 1, wherein the predetermined distance of each of the collapsible pusher assembly from the end of the carcass drum is adjustable.

5. The tire building apparatus as claimed in claim 1, wherein the pusher ring assembly comprises a disc shaped structure mounted on said shaft and plurality of radially extending collapsible pusher arms having a first end pivotally connected to the said disc shaped structure and a second free end wherein the first ends are spaced along the circumference of said disc.

6. The tire building machine as claimed in claim 5, wherein the expansion and collapse movement of the said pusher arms is achieved by actuating means such as spring, elastomeric rubber ring or an external actuator.

7. The tire building apparatus as claimed in claim 6, wherein the collapsible pusher arms of said pusher rings in an un-inflated state partially or completely supports the bladder ends of said bead setter assembly.

8. The tire building apparatus as claimed in claim 7, wherein the second end of each of the plurality of pusher arms comprises a circular profile or any other related profile in order to maintain smooth contact with the bladder, said profile preferably having a rolling surface, a first side surface and a second side surface such that, on expansion of said pusher arms, a first side surface of one arm abuts a second side surface of adjacent arm.

9. The tire building apparatus as claimed in claim 1, wherein said pair of internally threaded nuts are replacable with a further pair of slip assist mechanisms one on either sides of the externally threaded shaft.

10. The tire building apparatus as claimed in claim 9, wherein the pusher mechanism comprises a set of levers having one end connected to the pusher arms of the pusher ring assembly, said lever assisting expansion and collapse movement of said pusher arms.

11. A tire building method, said method comprising the steps of:

- receiving materials on a cylindrical carcass supporting body of a cylindrical carcass drum to form a cylindrical carcass;

- placing a first bead and a second bead on said cylindrical carcass drum such that a portion of the carcass between the first bead and the second bead is defined as a center carcass portion and portions of the carcass on either side of the center portion are overhang carcass portions;

- inflating the inflatable cylindrical carcass drum to inflate the center carcass portion and deactivating the slip assist mechanism such that both the bead setter assemblies and collapsible pusher assemblies moves towards the center carcass drum;

- inflating the bladders of the bead setter assemblies for partially folding the overhang portions of the cylindrical carcass over the first bead and the second bead and expanding pusher arms of pusher rings of the collapsible pusher assemblies; and

- activating the slip mechanism on each side of the carcass drum for locking the movement of the bead setter assemblies such that only the collapsible pusher assemblies move towards the cylindrical carcass drum and the expanded pusher arms of pusher rings pushes the inflated bladders which completely folds the overhang carcass portions onto the inflated center carcass portion to wrap the first and second beads for a complete turn up.