BACKGROUND

The invention relates to an apex formation assembly and a method for forming an apex for a tyre.

WO 00/23262 Al discloses a coiling apparatus for guiding an apex filler around a mandrel. The apex filler is extruded linearly and is subsequentlly prestressed around a mandrel. The coiling apparatus is provided with a V-shaped enclosure that forces the apex filler into a spiral shaped coil around the mandrel. The mandrel is cooled in its prestressed state to allow the apex filler to settle and to neutralize the stresses in the rubber material of the apex filler. The inner diameter of the settled apex filler is smaller than the outer diameter of the annular bead, such that during uncoiling, the settled apex filler requires another deformation prior to application around the bead.

JPH 08 118515 A discloses an extruder for extruding a bead filler around two juxtaposed drums. The bead filler is allowed to slack before being spirally wound around both drums into a non-circular shape, at which time the bead filler is cooled by cooling water in order to settle. The bead filler is subsequently discharged to a bead filler former drum, where the bead filler is cut-to- length and bonded to form a ring-like bead filler.

In both disclosures, the fillers are deformed considerably after extrusion, thereby causing stress in the rubber material of the filler, in particular around the radially outside edge of the deformed filler. As a result, inconsistencies such as unpredictable wave patterns will occur in the filler, which prevent the filler from bonding consistently to other parts of the tyre. Although these stresses are subsequently neutralized by settling of the filler, any deformations that have already occurred will seriously affect the bonding ability of the filler.

Additionally, in both disclosures, the fillers are deformed again after settling and prior to application to the bead, thereby causing further and possible permanent stresses in the rubber material of the filler.

It is an object of the present invention to provide an apex formation assembly and a method for forming an apex for a tyre, wherein deformation of the apex is reduced .

SUMMARY OF THE INVENTION

According to a first aspect, the invention provides an apex formation assembly for forming an apex for a tyre, comprising a conveyor and an extruder, wherein the conveyor is provided with an entry point for receiving the apex from the extruder, an exit point for delivering the apex to a destination and a path for conveying the apex from the entry point to the exit point, wherein the path of conveyance extends helically between the entry point and the exit point, wherein the extruder is arranged for nonlinear extrusion of the apex, wherein the extruded apex, if unaffected by external forces after extrusion, assumes a natural curvature, wherein the extruder is arranged in a position with respect to the conveyor for extruding the apex through the entry point at its natural curvature, wherein, at the entry point, the natural curvature of the apex is substantially tangent to the curvature of the helical path of conveyance. By feeding the apex at its natural curvature tangentially into the helical path of conveyance, deformation, stress or tension in the rubber material of the apex during extrusion, formation and conveyance of the apex can be reduced, prevented or even eliminated .

In an embodiment the natural curvature of the apex is concentric to the helical path of conveyance. The apex can thus be conveyed concentrically along the helical path of conveyance at its natural curvature.

In an embodiment the radii of the helical path of conveyance and the natural curvature of the apex are substantially the same. Thus, the apex can automatically travel along the helical path of conveyance without any substantial deformation, stress or tension in the rubber material of the apex.

In an embodiment the extruder comprises a die arranged for extruding the apex in an initial direction of extrusion, wherein the initial direction of extrusion is tangent to the helical path of conveyance or its helical prolongation. In this manner, the apex leaving the extruder in a non-linear manner can curve tangentially into the helical path of conveyance, immediately after leaving the die .

In an embodiment the die is positioned at or near the entry point of the conveyor for extruding the apex directly onto the conveyor. By extruding the apex directly onto the conveyor, the apex can be supported by the conveyor immediately after extrusion. This prevents deformation of the apex due to gravitational forces.

In an embodiment the conveyor is provided with a center column which is concentric to the helical path of the conveyance and a plurality of supporting elements extending radially from the center column, wherein the plurality of supporting elements are substantially evenly distributed along the helical path of conveyance to form a helical support plane for the apex during conveyance. The support plane can stabilize the apex and can facilitate the conveyance of the apex along the helical path of conveyance . In an embodiment the supporting elements are supporting rollers, preferably conical supporting rollers with an outwardly increasing diameter for biasing the apex to move inwards. The supporting rollers can reduce friction when the apex slides over the supporting rollers during conveyance. The supporting rollers can be driven to regulate the speed of conveyance of the apex. The conical supporting roller can prevent the apex from diverting from its natural curvature due to centrifugal forces.

In an embodiment the conveyor is provided with a plurality of boundary elements extending parallel to the center column, wherein the boundary elements are substantially evenly distributed along the inside of the helical path of conveyance to form a helical inner boundary for the apex. The helical inner boundary can define a minimum radius for the helical path of conveyance.

In an embodiment at least one of the boundary elements is disposed between a pair of directly subsequent supporting elements. In combination with the supporting elements, the boundary elements can define a minimum radius for the helical path of conveyance on the support plane of the conveyor.

In an embodiment the boundary elements are boundary rollers. The boundary rollers can reduce friction when the apex slides past the boundary rollers during conveyance .

In an embodiment the minimum radius of the helical path of conveyance is defined by the radius of the helical inner boundary, wherein the radial positions of the boundary elements with respect to the center column are adjustable to substantially match the minimum radius of the helical inner boundary to the radius of the natural curvature of the apex. By matching the minium radius of the helical inner boundary to the radius of the natural curvature of the apex, the apex can be extruded at its natural curvature closely around the helical inner boundary. The helical inner boundary can prevent deformation of the apex to a curvature which is smaller than its natural curvature.

In an embodiment the radial position of the extruder with respect to the center column is adjustable to substantially match the radius of the natural curvature of the apex. Thus, the apex can be extruded with its natural curvature extending concentrically with respect to the center column.

In an embodiment the assembly further comprises a bead drum for holding a substantially circular bead with an outside bead diameter, wherein the conveyor is arranged for delivering the apex to the bead, wherein diameter of the helical path of conveyance is substantially the same as the outside diameter of the bead. The apex can thus be conveyed along the helical path of conveyance at a diameter at which the apex can be applied to the bead without any substantial deformation .

In an embodiment the bead drum is arranged concentrically with respect to the helical path of conveyance. The apex can thus be concentrically delivered from the conveyor to the bead drum. As the apex is already at the right diameter, the apex can be applied around the bead at its natural curvature.

In an embodiment the center axis of the helical path of conveyance is substantially vertical, wherein the entry point is at the top end of the helical path of conveyance and the exit point is at the bottom end of the helical path of conveyance, wherein the bead drum is arranged near the exit point at the bottom of the helical path of conveyance. By extruding at the top and delivering at the bottom of the conveyor, the conveyance from the apex through the conveyor can be aided by gravity. Also, the apex can be delivered to the bead drum with the aid of gravity .

In an embodiment the assembly further comprises a festoon, wherein the apex is delivered from the exit point of the conveyor into the festoon. The festoon can act as a buffer or storage at the exit point of the conveyor.

In an embodiment the length of the helical path and/or the speed of conveyance are chosen such that, at the exit point of the conveyor, the apex has settled at its natural curvature. The settled apex can remember its original, natural curvature, so that it can return to its original, natural curvature after being deformed within the elastic range of the rubber material of the apex.

In an embodiment the assembly further comprises a cooling unit for cooling the apex on the conveyor. The cooling unit can accelerate the cooling down and/or settling of the apex on the conveyor.

According to a second aspect, the invention provides a method for forming an apex for a tyre, comprising the steps of extruding the apex, receiving the apex through an entry point onto a conveyor and conveying the apex on the conveyor along a path of conveyance to an exit point of the conveyor, wherein the apex is extruded in a non-linear manner, wherein the extruded apex, if unaffected by external forces after extrusion, assumes a natural curvature, wherein during the aforementioned steps, the apex is kept substantially at its natural curvature. By keeping the apex at its natural curvature, deformation, stress or tension in the rubber material of the apex during formation of the apex can be reduced, prevented or even eliminated .

In an embodiment the path of conveyance extends helically between the entry point and the exit point, wherein the step of extruding the apex involves extruding the apex through the entry point at its natural curvature, wherein, at the entry point, the natural curvature of the apex is substantially tangent to the curvature of the helical path of conveyance. By feeding the apex tangentially into the helical path of conveyance, deformation, stress or tension in the rubber material of the apex during formation of the apex can be reduced, prevented or even eliminated. In an embodiment the step of extruding the apex involves extruding the apex at an initial direction tangent to the helical path of conveyance or its helical prolongation. In this manner, the apex leaving the extruder in a non-linear manner can curve tangentially into the helical path of conveyance, immediately after leaving the die .

In an embodiment the step of extruding the apex involves adjusting the extrusion speed and/or the extrusion pressure such that the apex is extruded at a natural curvature with a radius that substantially matches the radius of the curvature of the helical path of conveyance. The apex can thus be extruded tangentially into the helical path of conveyance at the correct radius.

In an embodiment the radial position of the extruder is adjustable, wherein the method comprises the step of adjusting the radial position of the extruder with respect to the center column to substantially match the radius of helical path of conveyance. Thus, the apex can be extruded with its natural curvature extending concentrically with respect to the center column.

In an embodiment the method further comprises the step of delivering the apex to a circular bead at the exit point of the conveyor, wherein the bead has an outside bead diameter, wherein the diameter of the helical path of conveyance is adjustable, wherein the method comprises the step of, prior to extruding the apex, adjusting the diameter of the helical path of conveyance to substantially match the outside diameter of the bead. The apex can thus be conveyed along the helical path of conveyance at a diameter at which the apex can be applied to the bead without any substantial deformation.

In an embodiment, during the delivery of the apex to the bead, the apex is kept substantially at its natural curvature. By keeping the apex at its natural curvature, deformation, stress or tension in the rubber material of the apex during delivery of the apex to the bead can be reduced, prevented or even eliminated.

In an embodiment the method further comprises the steps of allowing the apex to settle in the conveyor at its natural curvature and delivering the apex to a festoon at the exit point of the conveyor, wherein the settled apex is deformed by the festoon within the elastic range of the rubber material of the apex, wherein the settled apex is allowed to return to its original, natural curvature after leaving the festoon. The festoon can act as a buffer or storage at the exit point of the conveyor. After the apex has returned to its original, natural curvature, the apex can be applied to a bead without substantial deformation.

The various aspects and features described and shown in the specification can be applied, individually, wherever possible. These individual aspects, in particular the aspects and features described in the attached dependent claims, can be made subject of divisional patent applications .

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be elucidated on the basis of an exemplary embodiment shown in the attached schematic drawings, in which:

figures 1 and 2 show a side view and a top view, respectively, of an apex formation assembly for forming an apex for a tyre, according to a first embodiment of the invention, wherein the assembly comprises a conveyor;

figure 3 shows a side view of the conveyor according to figure 1 in more detail;

figure 4 shows a top view of the conveyor according to figure 3 in more detail;

figure 5 shows a cross sectional side view of the conveyor according to the line V - V in figure 4;

figure 6 shows a perspective view of bottom end of the conveyor according to figures 3-5; figures 7 and 8 show side views of the bottom end of the conveyor according to figure 6; and

figures 9 and 10 show a side view and a top view, respectively, of an apex formation assembly for forming an apex for a tyre, according to a second embodiment of the invention .

DETAILED DESCRIPTION OF THE INVENTION

Figures 1 and 2 show an apex formation assembly 1 for forming an apex filler strip or an apex 9 for a tyre, according to a first exemplary embodiment of the invention. The apex formation assembly 1 comprises a conveyor 2, an extruder 3 for extruding the apex 9 onto the conveyor 2 and a turret 4 for receiving the apex 9 from the conveyor 2 and for joining the apex 9 to a bead 8 for forming an assembled bead-apex for a tyre.

As shown in figures 3-5, the conveyor 2 is provided with an entry point A for receiving the apex 9 from the extruder 3, an exit point B for delivering the apex 9 to the turret 4 and a path of conveyance P for conveying the apex 9 from the entry point A to the exit point B. The path of conveyance P is the intended path that the apex 9 should travel through the conveyor 2. The path of conveyance P extends spirally or helically between the entry point A and the exit point B. In this exemplary embodiment, the helical path of conveyance P has a substantially constant pitch or rate of descent. The diameter D of the helical path of conveyance P is constant throughout the helical path of conveyance P, but can be changed for the entire helical path of conveyance P.

The conveyor 2 comprises an upright, cylindrical central column 20 with a central axis S that extends substantially vertically. The helical path of conveyance P extends concentrically about this central axis S. The conveyor 2 is provided with a plurality of supporting elements 21 extending radially from the center column 20. The plurality of supporting elements 21 are evenly distributed along the helical path of conveyance P to form a helical support plane for the apex 9 during conveyance. Preferably, the supporting elements 21 along one revolution of the helical path of conveyance P are vertically aligned with the supporting elements 21 of a subsequent revolution of the helical path of conveyance P. The number of supporting elements 21 is chosen such that, with an even distribution along the helical path of conveyance P, the intermediate distance between two directly subsequent supporting elements 21 is small enough to prevent hanging of the apex 9 between the supporting elements 21.

In this exemplary embodiment, the supporting elements 21 are freely rotatable or actively driven conical supporting rollers 21 with an outwardly increasing diameter. When the apex 9 is conveyed over the conical supporting rollers 21, the outwardly increasing diameter thereof biases or gently forces the apex 9 to move in a radially inward direction towards the central column 20 and ensures that the apex 9 stays at the intended helical path of conveyance P.

The conveyor is provided with a plurality of boundary elements 22 extending parallel to the center axis S of the center column 20. The boundary elements 22 are substantially evenly distributed along the inside of the helical path of conveyance P to form a helical inner boundary for the apex 9 around the central column 20. The helical inner boundary limits the radially inward movement of the apex 9 and, as such, determines or defines a minimum radius for the helical path of conveyance P. Preferably, the boundary elements 22 along one revolution of the helical path of conveyance P are vertically aligned with the boundary elements 22 of a subsequent revolution of the helical path of conveyance P. The number of boundary elements 22 is chosen such that, with an even distribution along the helical path of conveyance P, the intermediate distance between two directly subsequent boundary elements 22 is small enough to prevent the apex 9 from passing in between the boundary elements 22. Preferably, one boundary element 22 is disposed in the intermediate space between each pair of subsequent supporting elements 21.

In this exemplary embodiment, the boundary elements 22 are freely rotatable, cylindrical boundary rollers 22 with a substantially constant diameter.

The conveyor 2 further comprises a frame provided with vertically extending frame members 23 in the form of rods. The frame members 23 extend through the intermediate spaces between the subsequent supporting elements 21 and support the boundary elements 22 disposed in those intermediate spaces. The radial positions of the frame members 23 with respect to the central axis S can be adjusted manually or by a drive (not shown) in a direction of radial variation V to change the radius or the diameter of the inner boundary. Preferably, the frame members 23 are operationally coupled to each other so that their radial positions can be adjusted in the radial direction V in unison to concentrically contract or expand the helical inner boundary defined by the boundary elements 22. By changing the radius of the helical inner boundary, the diameter D or the radius of the helical path of conveyance P can be adjusted in a manner which will be described hereafter .

As shown in figures 6-8, the conveyor 2 is provided with a cutting plate 24 and a knife or a cutter 25 at or near the exit point B at the bottom of the conveyor 2. The cutter 25 is arranged for, in cooperation with the cutting plate 24 cutting the extruded apex 9 into a apex strip with a definite length. In particular, the length of the apex 9 substantially matches a 360 degree revolution of the helical path of conveyance P. The cutting by the cutter 25 creates a leading end 91 for a new apex strip and a trailing end 92 for a previous apex strip (if applicable) .

As shown in figures 3 and 4, the extruder 3 is arranged at or near the entry point A at the upper side of the conveyor 2. Preferably, the extruder 3 is at a slight downward angle to match the pitch of the helical path of conveyance P. The radial position of the extruder 3 can be adjusted to match the radius of the helical path of conveyance P. The extruder 3 is provided with a pressure chamber 30 and a die 31. Preferably, the die 31 is positioned directly at or as close as possible to the entry point A of the conveyor 2.

To extrude the apex 9, unvulcanized, elastomeric or rubber material is supplied to the pressure chamber 30 and forced through the die 31 at a substantially constant extrusion pressure and a substantially constant extrusion speed. The die 31 is shaped so that the apex 9 is extruded with an asymmetrical cross section. Preferably, the cross section is substantially triangular, having a wide base that tapers or converges into a sharp edge. The die 31 is arranged for non-linear extrusion, such that the apex 9 is initially extruded in an initial extrusion direction X, but directly after extrusion assumes a natural curvature C in accordance with the non-linear extrusion angle. If unaffected by external forces, the apex 9 will continue along its natural curvature C.

As shown in figure 4, the extruder 3 is arranged in a position with respect to the conveyor 2 so that the apex 9 is extruded through the entry point A of the conveyor 2 at its natural curvature C. More specifically, the extruder 3 is arranged in a position with respect to the conveyor 2 so that the natural curvature C of the apex 9 at the entry point A of the conveyor 2 is substantially in line with, smoothly connecting to or tangent to the curvature of the helical path of conveyance P. Preferably, the extruder 3 is arranged in a position with respect to the conveyor 2 so that its initial extrusion direction X is at the same radius as and substantially in line with, smoothly connecting to or tangent to the helical path of conveyance P or its helical prolongation. Throughout the helical path of conveyance P, the apex 9 is conveyed with its natural curvature C substantially at the same radius as and substantially concentric to the helical path of conveyance P.

As shown in figures 1 and 2, the turret 4 is provided with a turret arm 40 and a turret drive 41 for driving the turret arm 40 in a rotational direction Z about an axis of rotation R. The turret arm 40 extends from both sides of the turret drive 41. The turret 4 is provided with a first drum 42 and a second drum 43 supported on opposite ends of the turret arm 40. Each drum 42, 43 comprises a peripheral wall or edge 44 with a drum axis T. The diameter of the peripheral wall or edge 44 is chosen to be able to receive or accommodate a substantially circular, endless bead 8 for a tyre with a specific bead size, bead diameter or bead radius.

In figures 1 and 2, the first drum 42 is in a first position vertically or directly beneath the conveyor 2 and the second drum 43 is in a second position displaced from the conveyor 2. The first drum 42 and the second drum 43 can be interchanged or alternated between the two positions by rotating the turret arm 40 over 180 degrees. The drum 42 in the first position is ready to receive the apex 9 from the conveyor 2, while the other drum 43 in the second position can be loaded and/or unloaded, as indicated with arrow U. The turret 4 is provided with a drum drive 45 with a friction wheel for driving the drum 42 in the first position .

Alternatively, a drum like the drums 42, 43 of the turret 4 can be separately provided at the first position for receiving the apex 9 from the conveyor 2. In such an embodiment, the separate drum would have to be loaded, unloaded and/or replaced by another separate drum by other means, for example manually or by a robot.

Optionally, the apex formation assembly 1 is provided with a cooling unit 5 for accelerating the cooling down and/or settling of the apex 9 on the conveyor 2. In this exemplary embodiment, the cooling unit 5 is a fan providing a cooling air flow over the apex 9 on the conveyor 2. Alternatively, the supporting elements 21 of the conveyor 2 are hollow and a circulation system (not shown) circulates a cooling medium, such as water, through the hollow supporting elements 21.

The method for forming the aforementioned apex 9 for a tyre generally comprises the steps of extruding the apex 9, receiving the apex 9 through the entry point A onto the conveyor 2, conveying the apex 9 on the conveyor 2 along the path of conveyance P to the exit point B of the conveyor 2 and delivering the apex 9 from the exit point B of the conveyor 2 to the bead 8 arranged on one of the drums 42, 43 that is - at that moment - arranged in the first position underneath the conveyor 2. As indicated before, the extruder 3 is arranged for extruding the apex 9 in a non-linear manner, wherein the extruded apex 9, if unaffected by external forces after extrusion, assumes the natural curvature C as shown in figure 4. During the steps of the method, the apex 9 is kept substantially at its natural curvature C. By keeping the apex 9 at its natural curvature C throughout the steps of the method, deformation of the apex 9 from its original, natural curvature C can be prevented. As a result, the apex 9 can be extruded onto, conveyed through and delivered from the conveyor 2 to the bead 8 without any substantial deformation, stress or tension in the rubber material of the apex 9.

The steps of the method will now be further elucidated on the basis of figures 1-8.

Prior to the step of extruding the apex 9, the apex formation assembly 1 has to be set for a specific bead 8 which is - at that moment - loaded onto the first drum 42 in the first position directly underneath the conveyor 2. The radial positions of the boundary elements 22, as shown in figure 4, are adjusted in the radial variation direction V so that the radius or the minimum radius or diameter D of the helical path of conveyance P defined by the boundary elements 22 substantially matches the outside radius or the outside diameter of the bead 8, as shown in figure 1, to which the apex 9 is to be applied. The radial position of the extruder 3 is adjusted to substantially match the radius of the helical path of conveyance P and the outside radius of the bead 8. As shown in figure 4, the extrusion pressure, the extrusion speed and/or the characteristics of the die 31 are adjusted to produce an apex 9 with a natural curvature C that substantially matches the angle, the radius or the curvature of the helical path of conveyance P. The apex formation assembly 1 is now ready to start with the extrusion of the apex 9.

The step of extruding the apex 9 involves extruding the apex 9 through the entry point A of the conveyor 2 at its natural curvature C. The position of the extruder 3 with respect to the conveyor 2 is chosen such that the natural curvature C, at the entry point A of the conveyor 2, is substantially tangent the curvature of the helical path of conveyance P. Preferably, the initial extrusion direction X is substantially tangent to the helical path of conveyance P or its helical prolongation. As a result, the extruded apex 9 can be smoothly transferred from the extruder 3 onto the conveyor 2, thereby reducing or eliminating stress, tension or deformation in the rubber material of the extruded apex 9.

As shown in figure 1, the extruded apex 9 has been conveyed through the conveyor 2 along the helical path of conveyance P towards the exit point B. During conveyance, the apex 9 is kept substantially at its natural curvature C, again reducing or eliminating stress, tension or deformation in the rubber material of the extruded apex 9. The relation between the extrusion speed, the speed of conveyance and the helical length of the helical path of conveyance P is chosen such that the extruded apex 9 is allowed to cool down during its conveyance to such an extent that, at the exit point B, the apex 9 will have settled in its original, natural curvature C. With 'settled', a substantially stabilized state is meant wherein the apex 9, if deformed within its elastic range, will always return to its original, natural curvature C. The rubber material of the apex is typically settled when cooled down.

Figures 6-8 show subsequent steps of the extruded apex 9 arriving at the exit point B and of delivering the apex 9 to the bead 8 at the first drum 42.

Figure 6 shows the situation wherein the extruded apex 9 arrives at the cutting plate 24. The cutter 25 cuts the extruded apex 9 to form a clean cut leading end 91 at the front thereof. The cut of waste material falls into a scrap bin (not shown) . The first drum 42 is driven by the drum drive 45, as shown in figure 1, wherein the rotational speed of the first drum 42 is synchronized to the conveying speed of the apex 9.

Figure 7 shows the situation wherein the first drum 42 has been rotated over almost a full revolution of 360 degrees while the apex 9 has been wound or applied around the bead 8 on the first drum 42. The leading end 91 of the apex 9 is about to intersect with the winded apex 9. At this moment, the cutter 25 is again operated to cut the apex 9 into an apex strip 90 with a length substantially corresponding to a full revolution of 360 degrees of the helical path of conveyance P.

Figure 8 shows the situation wherein the apex 9 has been cut into the aforementioned strip. The cut has created a trailing end 92 for the apex strip 90 that is being applied, while at the same time, the cut has created a leading end 91 for a subsequent length apex 9 to be cut at into a subsequent apex strip 90 at the cutter 25. As such, each revolution of 360 degrees of the apex 9 along the helical path of conveyance P represents an apex strip to be cut at the cutter 25. The first drum 42 is rotated further to completely pull the apex strip 90 from the conveyor 2 onto the first drum 42. When the trailing end 92 of the apex strip 90 falls off the edge of the cutting plate 24, it will come into abutment with the leading end 91 of the same apex strip 90. The leading end 91 and the trailing end 92 of the apex strip 90 can subsequently be stitched to form an endless apex strip 90 around the bead 8. Together, the apex strip 90 and the bead 8 form an assembled bead-apex for a tyre.

In the situation as shown in figure 2, the second drum 43 has been provided with another bead 8 and is ready to receive a subsequent length of apex 9. After the apex strip 90 has been applied to the bead 8 on the first drum 42, the turret arm 40 can be rotated in the rotational direction Z to alternate the first drum 42 and the second drum 43 between the first and second positions. The first drum 42 can then be unloaded in the second position while the second drum 43 - now in the first position - is ready to receive the subsequent length of apex 9 from the conveyor 2. While the subsequent length of apex 9 is delivered to the bead 8 on the second drum 43, the first drum 42 can be loaded with a new bead 8.

Figures 9 and 10 show an alternative apex formation assembly 101 for forming an apex filler strip or an apex 9 for a tyre, according to a second exemplary embodiment of the invention. The alternative apex formation assembly 101 is provided with a conveyor 2, an extruder 3 and an optional cooling unit 5 which are substantially identical in form and operation to the previously described conveyor 2, the extruder 3 and the optional cooling unit 5 of the apex formation assembly 1 according to the first embodiment of the invention. The conveyor 2, the extruder 3, the cooling unit 5 and their operation will therefore not be recited in detail hereafter.

The alternative apex formation assembly 101 differs from the apex formation assembly 1 according to the first embodiment of the invention, in that it is provided with a festoon 6 downstream of the exit point B of the conveyor 2. The festoon 6 is provided with lower rollers 61 and upper rollers 62. The height H between the lower rollers 61 and the upper rollers 62 can be regulated to change the capacity and the output speed of the festoon 6.

The apex 9 which exits the conveyor 2 through the exit point B is fed as a substantially continuous length into the festoon 6. The apex 9 is not cut at the exit point B. The conveyor 2 does therefore not need to have the cutting plate 24 and the cutter 25 as shown in figure 6. The apex 9 is deformed within its elastic range to a straight or linear shape in the festoon 6. This deformation from the natural curvature C into a linear shape happens after the apex 9 has settled in the conveyor 2. The apex 9 will therefore remember its settled, natural curvature C and will return to this natural curvature C as soon as it is no longer being deformed in the festoon 6.

The apex 9 travels underneath the lower rollers 61 and over the upper rollers 62 in a meandering pattern until it leaves the festoon 6 at the downstream end. At the downstream end of the festoon 6, a conventional bead-apex application unit (not shown) can be arranged for applying the apex 9 to a bead 8. At the bead-apex application unit, the apex 9 is allowed to return to its original curvature C without deformation.

The festoon 6 can act as a temporary storage or buffer between the exit point B of the conveyor 2 and the bead-apex application unit. By increasing the height H between the rollers 61, 62, the output speed of the apex 9 from the festoon 6 can be temporarily slowed down to allow for changing removing an assembled bead-apex at the bead- apex application unit and to allow for loading a new bead into the bead-apex application unit.

It is to be understood that the above description is included to illustrate the operation of the preferred embodiments and is not meant to limit the scope of the invention. From the above discussion, many variations will be apparent to one skilled in the art that would yet be encompassed by the scope of the present invention.