Tire building drum and method for turning up tire components

Abstract

The present invention relates to a tire building drum and a method for turning up tire components, the tire building drum comprising a drum body rotatable about a drum axis, an inflatable turn-up bladder extending circumferentially about the drum axis around the drum body for turning up tire components supported on the turn-up bladder, and a plurality of pressure arms for pressing the turn-up bladder during turn-up of the tire components, the tire building drum comprising a plurality of hinges for hingedly connecting the pressure arms to the drum body, the plurality of hinges being located below the turn-up bladder when the turn-up bladder is not inflated, the tire building drum being provided with an underlay extending radially between at least one of the plurality of hinges and the turn-up bladder.

Description

Background Art

[0001] The present invention relates to a tire building drum and a method for turning up tire components.

[0002] WO2019 / 199160A1 discloses a tire building drum comprising a first drum half, a second drum half, and a central section located axially between the first drum half and the second drum half. The tire building drum further comprises a turn-up bladder for turning up tire components extending around the first drum half and the second drum half and supported on the turn-up bladder. The tire building drum further comprises a plurality of pressing arms located between the non-inflated turn-up bladder and the respective drum halves for pressing the turn-up bladder during the turn-up of the tire components. The pressing arms are hinged on the respective drum halves at a position located under the turn-up bladder when not inflated.

Summary of the Invention

[0003] A disadvantage of known tire building drums is that the turn-up bladder is directly supported on the pressing arms and their respective hinges. During the turn-up of the pressing arms, during their subsequent return to the rest position, and / or during the expansion or contraction of the tire building drum, the turn-up bladder may catch, jam, or be pinched between the pressing arms and / or their respective hinges. In particular, due to the inclination of the pressing arms during the turn-up operation, the turn-up bladder is pushed towards and / or into any gap at the respective hinge. When pinched repeatedly, the bladder may no longer be uniform or airtight, and the turn-up bladder may be severely damaged to the extent that it has to be replaced.

[0004] An object of the present invention is to provide a tire building drum and a method for turning up tire components that can improve the lifespan of the turn-up bladder.

[0005] According to a first aspect, the present invention provides a tire building drum, the tire building drum including a drum body rotatable about a drum axis, an inflatable turn-up bladder extending circumferentially about the drum axis around the drum body for turning up a tire component supported on the turn-up bladder, and a plurality of pressing arms distributed circumferentially around the drum body and positioned between the drum body and the turn-up bladder for pressing the turn-up bladder during the turning up of the tire component. The tire building drum includes a plurality of hinges for hinge-connecting the pressing arms to the drum body, the plurality of hinges being positioned below the turn-up bladder when the turn-up bladder is not inflated. The tire building drum is provided with an underlay extending between at least one of the plurality of hinges and the turn-up bladder in a radial direction perpendicular to the drum axis.

[0006] In the context of the present invention, the term "underlay" should be interpreted as a material layer placed under something else for protection or support. The underlay can support the turn-up bladder against the drum body at the location of at least one hinge, thereby reducing the risk that the turn-up bladder is pinched at the at least one hinge. In particular, the underlay can have one or more of the following characteristics: it can slide more easily over the pressing arm than the turn-up bladder, it can have a relatively high compression resistance along the pressing arm or can be relatively rigid, it can have a larger minimum bending radius, and / or it can be relatively thick. Thus, the likelihood that the underlay itself gets stuck or pinched in the at least one hinge is reduced. Specifically, when the force applied to the underlay in the direction along the pressing arm exceeds the friction between the underlay and the pressing arm, the underlay can simply slide over the pressing arm, thereby also reducing the tension of the turn-up bladder that would otherwise push the turn-up bladder towards and / or into the at least one hinge. Furthermore, the minimum bending radius and / or the thickness of the underlay can shield the turn-up bladder from any sharp edges or acute angles at the at least one hinge and can provide a relatively smooth support surface for the turn-up bladder. Thus, the turn-up bladder is less likely to be damaged by the at least one hinge during turn-up. As a result, the lifespan of the turn-up bladder can be increased without modifying the turn-up bladder itself. Advantageously, the turn-up bladder can be designed to have optimal characteristics for turn-up without requiring reinforcement at the location of at least one hinge.

[0007] In one embodiment, the underlay has a first end fixed to the drum body on the side facing away from the plurality of pressing arms of the plurality of hinges. Alternatively, the drum body comprises a bead lock section, and the underlay has a first end fixed to the drum body on the side facing the bead lock section of the plurality of hinges. By fixing the underlay to the drum body at the first end, the underlay can be kept in place at or near at least one hinge. In other words, it is possible to prevent the underlay from shifting out of place where it could expose at least one hinge and damage the turn-up bladder.

[0008] In each of the foregoing embodiments, the underlay may have a second end opposite the first end, and the second end rests on at least one of the plurality of pressing arms. With the second end resting on at least one pressing arm, the underlay can effectively extend from the first end fixed on the drum body across the at least one hinge to a position on the at least one pressing arm.

[0009] Preferably, the second end is free, not fixed, or unconstrained to slide over the at least one pressing arm in an arm direction parallel to the at least one pressing arm. Thus, the position of the second end on the at least one pressing arm can passively follow or adapt itself according to the change in the orientation of the at least one pressing arm, thereby enabling the at least one pressing arm to turn up and press the turn-up bladder.

[0010] Additionally or alternatively, the underlay is at least partially deformable from a cylindrical configuration to a conical configuration. Thus, the conical portion of the underlay can passively follow or adapt itself to the combined turn-up of the plurality of pressing arms.

[0011] In one particular embodiment, the underlay comprises an underlay body that is annular at a first end and divided into a plurality of arm sections at a second end opposite the first end. Thus, the underlay body can cover the plurality of hinges in a continuous or substantially continuous manner at the first end while passively following or adapting to the change in the orientation of the plurality of pressing arms and the resulting diameter expansion at the second end.

[0012] Preferably, each arm section of the plurality of arm sections extends along each pressing arm of the plurality of pressing arms and is configured to rest on each pressing arm. Thus, each arm section can passively follow or adapt to the change in the orientation of each pressing arm while remaining on each pressing arm.

[0013] In a further embodiment thereof, the underlay body is deformable from a cylindrical configuration to a conical configuration in the plurality of arm sections. Thus, as described above, the conical portion of the underlay can passively follow or adapt itself to the combined turn-up of the plurality of pressing arms.

[0014] Preferably, the underlay body is provided with a plurality of slits that divide the underlay body into a plurality of arm sections. Due to the slits, the arm sections can be variably circumferentially spaced apart at the second end in response to the change in the orientation of the pressing arms. In particular, the arm sections can expand to follow the spread of the pressing arms when the pressing arms move or expand towards a larger diameter.

[0015] More preferably, the plurality of slits extend parallel to each other in the cylindrical configuration of the underlay body. As a result, the arm sections defined by the slits can also extend parallel to each other in the cylindrical configuration.

[0016] Most preferably, the plurality of slits extend over at least half of the length of the underlay body between the first end and the second end. Thus, at least half of the length of the underlay body can be expanded from the cylindrical configuration to the conical configuration, and less than half of the underlay body can remain in the cylindrical configuration to effectively shield the turn-up bladder from the plurality of hinges.

[0017] In a further embodiment, the underlay body comprises a plurality of bridge portions, each bridge portion of the plurality of bridge portions interconnects a pair of arm sections of the plurality of arm sections at the first end, and each bridge portion has a circumferential elasticity greater than the circumferential elasticity of the respective pair of arm sections it interconnects. Thus, the diameter of the underlay body can be expanded at least at the first end to enable attachment of the underlay body to the drum body at the first end. Further, the underlay can be removed from the drum body without damaging the underlay body.

[0018] Preferably, the underlay body has a first thickness in the plurality of arm sections and a second thickness smaller than the first thickness in the plurality of bridge portions. By reducing or thinning the thickness of the bridge portion, the elasticity of the underlay body in each bridge portion can be increased.

[0019] Additionally or alternatively, the underlay body comprises a different material in the plurality of bridge portions compared to the plurality of arm sections. The material of the bridge can be selected to have a higher circumferential elasticity than the material of the plurality of arm sections.

[0020] In a further embodiment, the underlay body comprises layers of different configurations in a plurality of bridge portions as compared to the plurality of arm sections. In particular, the underlay body may comprise a laminate of a first layer having a first elasticity and a second layer having a second elasticity greater than the first elasticity, wherein the second layer is covered by the first layer in the plurality of arm sections and is exposed in the plurality of bridge portions. Thus, the second layer can elastically expand circumferentially in the bridge portions, whereas its elasticity is restricted by the first layer in the arm sections.

[0021] In yet another alternative embodiment, the underlay body is spliced at a first end to form an annular configuration. By splicing the underlay body, the underlay body itself does not necessarily have to be elastic in the circumferential direction. Instead, it can be inelastic in that circumferential direction.

[0022] In yet another alternative embodiment, the underlay comprises a plurality of arm sections extending separately from a first end towards a second end opposite the first end. By forming an underlay having separate arm sections, neither elasticity nor bridge portions are required between the arm sections. Instead, each arm section can be separately attached at a certain position on its respective pressing arm.

[0023] Preferably, each arm section of the plurality of arm sections extends along its respective pressing arm of the plurality of pressing arms and is configured to rest on its respective pressing arm. Thus, each separately attached arm section can passively follow or adapt to changes in the orientation of its respective pressing arm while remaining on it.

[0024] In another embodiment, the underlay has a first end fixed to the drum body by one or more fasteners. Thus, it is possible to prevent the underlay from coming off the drum body at its first end.

[0025] Preferably, the one or more fasteners comprise a group of fasteners including pins, bolts, clamps, or ridges. Such fasteners may, for example, mechanically engage the drum body by threading or may interact with the drum body in a form - fit manner.

[0026] According to a second aspect, the present invention provides a method for turning up tire components using a tire building drum according to any one of the embodiments of the first aspect of the present invention, the method comprising: - providing an underlay between at least one hinge and a turn - up bladder in the radial direction; - supporting the turn - up bladder on the underlay at at least one hinge during the turning up of the tire component.

[0027] The method according to the second aspect of the present invention relates to a practical implementation of the tire building drum according to the first aspect of the present invention and thus has the same technical advantages and will not be repeatedly described hereinafter.

[0028] According to a third aspect not recited in the claims, the present invention provides an underlay for use within a tire building drum according to any one of the embodiments of the first aspect of the present invention. The underlay according to the second aspect of the present invention has the same technical advantages when implemented within the tire building drum according to the first aspect of the present invention and will not be repeatedly described hereinafter.

[0029] According to a fourth aspect not recited in the claims, the present invention provides for the use of an underlay according to the second aspect of the present invention within a tire building drum according to any one of the embodiments of the first aspect of the present invention. The use according to the third aspect of the present invention relates to a practical implementation of the underlay within the tire building drum according to the first aspect of the present invention and thus has the same technical advantages and will not be repeatedly described hereinafter.

[0030] The various aspects and features described and illustrated in this specification can be applied individually whenever possible. These individual aspects, particularly those described in the appended dependent claims, may form the subject matter of a divisional patent application.

[0031] The present invention will be described based on exemplary embodiments shown in the accompanying schematic diagrams.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Modes for Carrying Out the Invention

[0033] Figs. 1 and 2 show a tire building drum 1 according to a first embodiment of the present invention for assembling a green tire or an unvulcanized tire (not shown).

[0034] The tire building drum 1 is arranged, adapted, or configured to form the carcass of a tire by turning up a tire component T, particularly a pre - assembly, around a bead B. The pre - assembly typically includes an inner liner, one or more body plies, and sidewalls.

[0035] As shown in Fig. 1, the tire building drum 1 includes a drum body 10 rotatable about a drum axis S. In this example, the drum body 10 is mounted on a drum shaft 9. The drum body 10 has an axial direction A parallel to the drum axis S and a radial direction R perpendicular to the drum axis S and / or the axial direction A. In this example, the drum body 10 comprises only a drum half of the tire building drum 1. The tire building drum 1 comprises two such drum halves arranged on either side of a central section (not shown) in a manner known per se. Note that Fig. 1 shows only the portion of the drum body 10 above the drum axis S. Each drum half is provided with a bead lock section 11 for clamping a bead B to the drum body 10 on each side of the central section.

[0036] As best seen in FIG. 2, the tire building drum 1 is provided with an inflatable turn-up bladder 2. The turn-up bladder 2 extends circumferentially C about the drum axis S around the drum body 10. The turn-up bladder 2 has an airtight bladder body 20 having a first peripheral edge 21 and a second peripheral edge 22 that are clamped and sealed to the drum body 10 on both sides of the bead lock section 11. In FIG. 1, the bladder body 20 is folded at the fold 23. The tire building drum 1 is connectable to a compressed air source arranged in air communication with the turn-up bladder 2, and in order to turn up the tire component T supported on the turn-up bladder 2, the bladder body 20 between the peripheral edges 21, 22 is inflated from the non-inflated state shown in FIG. 1 to the inflated state shown in FIG. 2. The turn-up bladder 2 is elastic in the circumferential direction C.

[0037] As shown in FIGS. 1 and 2, the tire building drum 1 further includes a plurality of pressing levers or pressing arms 3 distributed circumferentially C around the drum body 10. The pressing arm 3 is located radially R between the drum body 10 and the turn-up bladder 2 at least when the pressing arm 3 is in the position where the arm is lowered as shown in FIG. 1 and when the turn-up bladder 2 is not inflated. In particular, the bladder body 20 rests on the pressing arm 3 in the non-inflated state of the turn-up bladder 2. Each pressing arm 3 has an elongated arm body 30 extending in the arm direction D. The pressing arm 3 is rotatable, tiltable, or pivotable from the horizontal position or the position where the arm is lowered shown in FIG. 1 to the inclined position or the position where the arm is raised in order to press the turn-up bladder 2 during the turn-up of the tire component T. In this way, the turn-up bladder 2 can be biased toward the tire component T during the turn-up and come into close contact with the tire component T. In the position where the arm is lowered in FIG. 1, the pressing arm 3 extends parallel or substantially parallel to the axial direction A. In particular, in the position where the arm is lowered, the pressing arm 3 defines a substantially cylindrical surface of the tire building drum 1 for supporting the turn-up bladder 2.

[0038] The tire building drum 1 includes a plurality of hinges 4 for hinge - connecting the pressing arm 3 to the drum body 10. The hinges 4 are distributed around the drum body 10 centered on the drum axis S. In this example, the hinges 4 are supported by an annular arm support. The hinges 4 are located on the side facing the bead lock section 11 of the pressing arm 3, that is, on the side closest to the bead lock section 11 of the pressing arm 3. In other words, when the arm is in the lowered position, the pressing arm 3 extends from the hinge 4 in a direction away from the bead lock section 11. Therefore, pivoting the pressing arm 3 towards the raised - arm position in FIG. 2 includes at least a vector component in a direction parallel to the axial direction A towards the bead lock section 11.

[0039] It should be noted that in this example, the second peripheral portion 22 of the turn - up bladder 20 is clamped to the drum body 10 at a position between the bead lock section 11 and the hinge 4. When the turn - up bladder 2 is not inflated, the fold 23 lies on the pressing arm 3 at a position outside the region defined between the first peripheral portion 21 and the second peripheral portion 22. In other words, at least a part between the fold 23 and the second peripheral portion 22 of the non - inflated turn - up bladder 2 covers the pressing arm 3. Further, when the turn - up bladder 2 is not inflated, the plurality of hinges 4 are located below the turn - up bladder 2 or covered by the turn - up bladder 2.

[0040] As shown in FIGS. 1 and 2, the tire building drum 1 is provided with a support layer or underlay 5 that extends across the hinge 4 or over the hinge 4 at the hinge 4. The underlay 5 is adapted, arranged, or configured to support the turn-up bladder 2 with respect to the drum body 10 at the position of the hinge 4. In particular, the underlay 5 is positioned to extend or be located between the hinge 4 and the turn-up bladder 2 in the radial direction R, as shown in FIG. 1, when at least the pressing arm 3 is in the lowered position of the arm and when the turn-up bladder 2 is not inflated. Thus, the underlay 5 can prevent direct contact between the turn-up bladder 2 and the hinge 4.

[0041] In this exemplary embodiment, the underlay 5 has an underlay body 50. The underlay body 50 comprises a material layer that can effectively shield the hinge 4 from the turn-up bladder 2. In this example, the material layer is non-elastic or substantially non-elastic, at least within the normal range of forces applied to the underlay body 50 during turn-up. Alternatively, the material layer may be elastic in only one direction, for example, in the circumferential direction C.

[0042] In this example, the underlay body 50 is made of a material having durability comparable to that of the material used for conveyor belts. The durable material can be, for example, a fabric. Alternatively, a metal, such as spring steel, may be used.

[0043] The underlay body 50 preferably has the following properties, namely, - The underlay body 50 has a coefficient of friction with respect to the pressing arm 3 that is lower than the coefficient of friction of the turn-up bladder 2 with respect to the pressing arm 3 when the turn-up bladder 2 is directly supported on the pressing arm 3, preferably 80 percent or less, most preferably 50 percent or less. - The underlay body 50 has a compressive resistance along the pressing arm 3 that is higher than the compressive resistance of the turn-up bladder 2 along the pressing arm 3, preferably at least 120 percent, most preferably at least 150 percent higher. - The underlay body 50 has a minimum bending radius that is larger than the minimum bending radius of the turn-up bladder 2 before kinking, preferably at least 120 percent larger, most preferably at least 150 percent larger, and - The underlay body 50 has one or more of the characteristics of having a thickness of at least 1 millimeter, preferably at least 2 millimeters.

[0044] As shown in FIG. 3, the underlay body 50 is continuous, ring-shaped, and / or annular at the first end 51. The underlay body 50 is fixed to the drum body 10 at the first end 51. In this example, the first end 51 is attached or fixed to the drum body 10 on the side facing away from the pressing arm 3 of the hinge 4. More specifically, the first end 51 is attached or fixed to the drum body 10 at a position between the hinge 4 and the second peripheral edge 22 of the bladder body 20. The underlay 5 is fixed to the drum body 10 using a suitable fastener 7, such as a pin, bolt, or clamp.

[0045] To enable the annular first end 51 of the underlay body 50 to be fitted or attached around the drum body 10, the underlay body 50 may first be provided as a strip of material having a first joining edge 53, a second joining edge 54, and optionally a joining lip 55, as shown in FIG. 4, which can be joined or bonded into an annular configuration around the drum body 10 by joining the first joining edge 53 to the second joining edge 54 or vice versa, with or without using the joining lip 55. The underlay 5 can be removed from the drum body 10 by separating the joining edges 53, 54, i.e., by cutting the underlay body 50 along the joint or junction.

[0046] At the second end 52 opposite the first end 51, the underlay body 50 is supported by a plurality of pressing arms 3 or is placed on the plurality of pressing arms 3. The second end 52 is not fixed, is released, and / or is not constrained, and thus can passively move or slide freely along the respective arm bodies 30 of the pressing arms 3. In other words, the second end 52 is slidable on the arm body 30 in the arm direction D.

[0047] The underlay body 50 is at least partially expandable, deformable, or shape-changeable from the cylindrical configuration shown in FIG. 1 to the conical configuration shown in FIG. 2. In particular, at, near, or towards the second end 52, the underlay 5 is provided with a plurality of cuts or slits 56 that divide the underlay body 50 into a plurality of finger portions or arm sections 58. In the cylindrical configuration of the underlay 5 shown in FIG. 3, the slits 56 extend parallel to each other and / or parallel to the drum axis S, the axial direction A, and / or the arm direction D. As a result, the arm sections 58 also extend parallel to each other. In particular, each arm section 58 extends parallel to the arm direction D of the respective pressing arm 3.

[0048] The underlay 5 is attached to the drum body 10 such that each arm section 58 extends along and is placed on the respective pressing arm 3 of the plurality of pressing arms 3. Due to the slits 56, the arm sections 58 can be variably separated in the circumferential direction C at the second end 52 in response to a change in the orientation of the pressing arms 3. In particular, the arm sections 58 expand to follow the spread of the pressing arms 3 when the pressing arms 3 move or expand towards a larger diameter corresponding to the conical configuration of FIG. 2.

[0049] Each arm section 58 may have the same width or extent along the same arc length as each pressing arm 3 in the circumferential direction C, or may be wider than each pressing arm 3 so as to also extend into the circumferential gap between the next pressing arms 3. Thus, the arm section 58 can also prevent the turn-up bladder 2 from being pinched or getting stuck between the pressing arms 3 when the pressing arms 3 contract inwardly.

[0050] Note that the plurality of slits 56 extend over at least half of the length L of the underlay body 50 between the first end 51 and the second end 52. In this example, the slits 56 extend over at least 70 percent, preferably at least 90 percent, of the length L. Optionally, the slits 56 terminate at appropriately formed slit ends 57, i.e., rounded slit ends 57 having a certain minimum radius, to prevent the slits 56 from splitting into the underlay 5 towards the first end 51 beyond their respective slit ends 57.

[0051] The underlay 5 further has attachment elements 59, in particular attachment holes, for receiving the aforementioned fasteners 7 for attaching the underlay body 50 to the drum body 10. Alternatively, the underlay 5 can be held relative to the drum body 10 using pins that fit into corresponding holes. For example, the fastener 7 can be a pin that fits into the attachment hole 59. In this situation, when the turn-up bladder 2 is attached on the underlay 5, it can prevent the pin from coming out of the attachment hole during use. Conversely, the pin may be connected or integrated to the underlay 5, and the attachment hole may be provided in the drum body 10. This can also prevent the pin from coming out of the attachment hole during use when the turn-up bladder 2 is attached on the underlay 5.

[0052] Figures 5 and 6 show an alternative underlay 105 according to a second embodiment of the present invention for use with the tire building drum 1 according to FIGS. 1 and 2. The alternative underlay 105 differs from the above-described underlay 5 in that the underlay body 150 includes a plurality of bridge portions 106.

[0053] Each bridge portion 106 interconnects a pair of arm sections 58 at a first end 51. In this example, the bridge portion 106 is the only part of the underlay body 150 that interconnects the arm sections 58. In other words, the arm sections 58 are interconnected only by the bridge portion 106 at the first end 51.

[0054] Each bridge portion 106 has a circumferential C elasticity E that is greater than the circumferential C elasticity of each pair of arm sections 58 that it interconnects. As best seen in FIG. 6, the underlay body 150 has a first thickness H1 in the plurality of arm sections 58 and a second thickness H2 that is less than the first thickness H1 in the plurality of bridge portions 106, 206. By having a smaller second thickness H2, the elasticity E of the bridge portion 106 relative to the rest of the underlay body 150 can be effectively increased.

[0055] The alternative underlay 105 has the technical advantage over the aforementioned underlay 5 that the bridge portion 106 allows for an expansion of the diameter of the underlay body 150 at least at the first end 51 for attaching the underlay body 150 to the drum body 10 without the need to couple or join the alternative underlay 105 in the drum body 10. Thus, the alternative underlay 105 can be manufactured and / or formed to have a continuous or annular first end 51 before fitting or attaching the alternative underlay 105 to the drum body 10. Further, the alternative underlay 105 can be removed from the drum body 10 without damaging the underlay body 150.

[0056] FIG. 7 shows a further alternative underlay 205 according to a third embodiment of the present invention for use with the tire building drum 1 according to FIGS. 1 and 2. The further alternative underlay 205 differs from the alternative underlays 105 of FIGS. 5 and 6 in that the underlay body 250 is provided with a bridge portion 206 having a layer of a different configuration compared to the plurality of arm sections 58. In this example, the further alternative underlay 205 comprises a laminate of a first layer 261, a second layer 262, and a third layer 263. In the arm section 58, the second layer 262 is sandwiched between, covered by, or attached to at least one of the other layers 261, 263, but the second layer 262 is the only layer that extends into the bridge portion 206. Thus, the second layer 262 is exposed within or at the bridge portion 206. The second layer 262 has an elasticity E greater than the elasticity of the other layers 261, 263. In particular, the other layers 261, 263 can be inelastic or substantially inelastic in the circumferential direction C, at least within the normal range of the forces applied to the underlay body 250 during turn-up.

[0057] If the second layer 262 has sufficient elasticity E in the circumferential direction C, the second layer 262 may extend towards or even up to the second end 52 in the region between the arm sections 58, for example as an alternative to having the slit 56, provided that the second layer 262 does not interfere with the operating range of the pressing arm 3.

[0058] As an alternative to the laminated layers 261, 262, 263, it is further envisioned that the bridge portion 206 may comprise a different material having a different elasticity E from the material of the arm section 58.

[0059] FIG. 8 shows a further alternative underlay 305 according to a fourth embodiment of the present invention for use with the tire building drum 1 according to FIGS. 1 and 2. The further alternative underlay 305 differs from the above-described underlays 5, 105, 205 in that it comprises a plurality of arm sections 358 extending separately from a first end 351 towards a second end 52 opposite the first end 351. In other words, the arm sections 358 are not interconnected at the first end 51 or at any point along their length. Each arm section 358 is individually fixed, attached, or mounted to the drum body 10. Further, each arm section 358 extends along and rests on its respective pressing arm 3. To ensure that each arm section 358 remains properly aligned with the pressing arm 3 on which it rests, a plurality of attachment elements 359, for example two spaced attachment holes, may be provided for each arm section 358.

[0060] FIG. 9 shows an alternative tire building drum 401 different from the aforementioned tire building drum 1 in that it comprises a further alternative underlay 405 different from the aforementioned underlays 5, 105, 205, 305 in that it is fixed or fastened at or near the first end 51 to the drum body 410 using a fastener 407 in the form of a ridge or ledge extending in the circumferential direction C about the drum axis S. The ridge or ledge may be continuous or discontinuous in the circumferential direction C. The drum body 410 is provided with correspondingly or complementarily shaped holes or grooves 412 for receiving the fastener 407 in a form-fitting manner. The further alternative underlay 405 is effectively clamped or confined between the bladder 2 and the drum body 410.

[0061] Next, a method for turning up the tire part T using the above-described tire building drum 1 and the use of any one of the above-described underlays 5, 105, 205, 305 within the tire building drum 1 will be briefly described with reference to FIGS. 1 and 2. It will be understood that the reference to the underlay 5 according to the first embodiment of the present invention is also applicable to the other underlays 105, 205, 305 with necessary modifications.

[0062] As shown in FIG. 1, the underlay 5 is provided between the hinge 4 and the turn-up bladder 2 having a cylindrical configuration and is placed on the pressing arm 3 in a position where the arm is lowered. The turn-up bladder 2 is not inflated and is directly supported by the underlay 5 at the hinge 4. The tire part T is applied around the tire building drum 1 and has a portion inside the bead B in the bead lock section 11 and a portion outside the bead B in the bead lock section 11. In this example, the portion inside the bead B of the tire part T is at least partially formed into a toroidal shape. The portion outside the bead B of the tire part T is placed on the turn-up bladder 2.

[0063] FIG. 2 shows a situation where the turn-up bladder 2 is inflated in order to turn up the portion outside the bead B of the tire part T around the bead B to reach and contact the portion inside the bead B of the tire part T. The pressing arm 3 is turned up from a position where the arm is lowered to a position where the arm is raised. The underlay 5 takes on at least a partially conical configuration in response to the turn-up of the pressing arm 3. The arm sections 58 remain in place on their respective pressing arms 3. During the turn-up of the pressing arm 3, each arm section 58 can shift or slide slightly in the arm direction D of the respective pressing arm 3 on which it is placed. However, the underlay 5 remains aligned with each pressing arm 3, and more specifically, remains in the position between the hinge 4 and the turn-up bladder 2, effectively shielding the turn-up bladder 2 from the acute angle or sharp edge formed at the hinge 4 as a result of the turn-up of the pressing arm 3.

[0064] After the turn-up, the pressing arm 3 may be returned to the position where the arm in FIG. 1 has descended or contracted, and the turn-up bladder 2 may deflate again. Thereafter, the tire building drum 1 is ready for another cycle of the method. During the inward movement of the pressing arm 3, the underlay 5 can effectively prevent the turn-up bladder 2 from being drawn into or pinched by the hinge 4.

[0065] It should be understood that the above description is included to illustrate the operation of the preferred embodiment and is not meant to limit the scope of the present invention. From the above description, many variations encompassed by the scope of the present invention will be apparent to those skilled in the art. The invention described in the original claims of the present application is appended below. [1] A tire building drum comprising a drum body rotatable about a drum axis, an inflatable turn-up bladder extending circumferentially about the drum axis around the drum body for turning up a tire component supported on the turn-up bladder, and a plurality of pressing arms distributed in the circumferential direction around the drum body, positioned between the drum body and the turn-up bladder, and for pressing the turn-up bladder during the turning up of the tire component, wherein the tire building drum comprises a plurality of hinges for hinge-connecting the pressing arms to the drum body, the plurality of hinges being located under the turn-up bladder when the turn-up bladder is not inflated, and the tire building drum is provided with an underlay extending in a radial direction perpendicular to the drum axis between at least one of the plurality of hinges and the turn-up bladder. [2] The tire building drum according to [1], wherein the underlay has a first end fixed to the drum body on a side facing away from the plurality of pressing arms of the plurality of hinges. [3] The tire building drum according to [1], wherein the drum body comprises a bead lock section, and the underlay has a first end fixed to the drum body on a side facing the bead lock section of the plurality of hinges. [4] The tire building drum according to [2] or [3], wherein the underlay has a second end opposite to the first end, and the second end is placed on at least one of the plurality of pressing arms. [5] The tire building drum according to [4], wherein the second end is free to slide on, not fixed to, or not constrained on the at least one pressing arm in an arm direction parallel to the at least one pressing arm. [6] The tire building drum according to [4] or [5], wherein the underlay is at least partially deformable from a cylindrical configuration to a conical configuration. [7] The underlay has an annular shape at the first end, and includes an underlay body that is divided into a plurality of arm sections at a second end opposite to the first end. The tire building drum according to any one of [1] to [6]. [8] Each of the plurality of arm sections of the plurality of arm sections extends along each of the plurality of pressing arms and is configured to rest on each of the plurality of pressing arms. The tire building drum according to [7]. [9] The underlay body is deformable from a cylindrical configuration to a conical configuration in the plurality of arm sections. The tire building drum according to [7] or [8].

[10] The underlay body is provided with a plurality of slits that divide the underlay body into the plurality of arm sections. The tire building drum according to [9].

[11] The plurality of slits extend parallel to each other in the cylindrical configuration of the underlay body. The tire building drum according to

[10] .

[12] The plurality of slits extend over at least half of the length of the underlay body between the first end and the second end. The tire building drum according to

[10] or

[11] .

[13] The underlay body includes a plurality of bridge portions. Each of the plurality of bridge portions interconnects a pair of arm sections among the plurality of arm sections at the first end. Each bridge portion has a circumferential elasticity greater than the circumferential elasticity of each pair of the interconnected arm sections. The tire building drum according to any one of [7] to

[12] .

[14] The underlay body has a first thickness in the plurality of arm sections and a second thickness smaller than the first thickness in the plurality of bridge portions. The tire building drum according to

[13] .

[15] The underlay body includes a different material in the plurality of bridge portions compared to the plurality of arm sections. The tire building drum according to

[13] or

[14] .

[16] The underlay body includes layers of different configurations in the plurality of bridge portions compared to the plurality of arm sections. The tire building drum according to any one of

[13] to

[15] .

[17] The underlay body includes a laminate of a first layer having a first elasticity and a second layer having a second elasticity greater than the first elasticity, and in the plurality of arm sections, the second layer is covered by the first layer, and in the plurality of bridge portions, the second layer is exposed. The tire building drum according to any one of

[13] to

[15] .

[18] The underlay body is joined so as to form an annular configuration at the first end. The tire building drum according to any one of [7] to

[17] .

[19] The underlay includes a plurality of arm sections extending separately from the first end toward a second end opposite to the first end. The tire building drum according to any one of [1] to [6].

[20] Each arm section of the plurality of arm sections extends along each pressing arm of the plurality of pressing arms and is configured to rest on each pressing arm. The tire building drum according to

[19] .

[21] The underlay has a first end fixed to the drum body by one or more fasteners. The tire building drum according to [1].

[22] The one or more fasteners include a group of fasteners including pins, bolts, clamps, or ridges. The tire building drum according to

[21] .

[23] A method for turning up a tire component using the tire building drum according to any one of [1] to

[22] , - Providing the underlay between the at least one hinge and the turn-up bladder in the radial direction; - Supporting the turn-up bladder on the underlay at the at least one hinge during the turn-up of the tire component. A method comprising the steps of.

Description of Symbols

[0066] 1…Tire assembly drum 10…Drum body 11…Bead lock section 2…Turn-up bladder 20…Bladder body 21…First peripheral part 22…Second peripheral part 23…Fold 3…Pressing arm 30…Arm body 4…Hinge 40…Arm support 5…Underlay 50…Underlay body 51…First end 52…Second end 53…First joint edge 54…Second joint edge 55…Joint lip 56…Slit 57…Slit end 58…Arm section 59…Attachment element 7…Fastener 9…Drum shaft 105…Alternative underlay 150…Underlay body 106…Bridge part 205…Further alternative underlay 250…Underlay body 206…Bridge part 261…First layer 262…Second layer 263…Third layer 305…Further alternative underlay 351…First end 358…Arm section 359... Attachment element 401... Alternative tire building drum 405... Further alternative underlay 407... Fastener 410... Drum body 412... Groove A... Axial direction B... Bead C... Circumferential direction D... Arm direction E... Elasticity H1... First thickness H2... Second thickness L... Length R... Radial direction S... Drum axis T... Tire component

Claims

1. A tire building drum comprising: a drum body rotatable about a drum axis; an expandable turn-up bladder extending circumferentially about the drum axis around the drum body for turning up a tire component supported on a turn-up bladder; and a plurality of pressing arms distributed in the circumferential direction around the drum body, located between the drum body and the turn-up bladder, and for pressing the turn-up bladder during the turning up of the tire component, wherein the tire building drum comprises a plurality of hinges for hinge-connecting the pressing arms to the drum body, the plurality of hinges being located under the turn-up bladder when the turn-up bladder is not inflated, and the tire building drum is provided with an underlay that slides over the pressing arms and extends between at least one of the plurality of hinges and the turn-up bladder in a radial direction perpendicular to the drum axis.

2. The tire building drum according to claim 1, wherein the underlay has a first end fixed to the drum body on a side facing away from the plurality of pressing arms of the plurality of hinges.

3. The tire building drum according to claim 1, wherein the drum body comprises a bead lock section, and the underlay has a first end fixed to the drum body on a side facing the bead lock section of the plurality of hinges.

4. The tire building drum according to claim 2 or 3, wherein the underlay has a second end opposite to the first end, and the second end is placed on at least one of the plurality of pressing arms.

5. The tire building drum according to claim 4, wherein the second end is free to slide over, not fixed to, or not constrained by the at least one pressing arm in an arm direction parallel to the at least one pressing arm.

6. The tire building drum according to claim 4, wherein the underlay is at least partially deformable from a cylindrical configuration to a conical configuration.

7. The underlay according to claim 1, comprising an underlay body that is annular at a first end and is divided into a plurality of arm sections at a second end opposite to the first end.

8. The tire building drum according to claim 7, wherein each of the plurality of arm sections extends along each of the plurality of pressing arms and is configured to rest on each of the pressing arms.

9. The tire building drum according to claim 7, wherein the underlay body is deformable from a cylindrical configuration to a conical configuration in the plurality of arm sections.

10. The tire building drum according to claim 9, wherein the underlay body is provided with a plurality of slits that divide the underlay body into the plurality of arm sections.

11. The tire building drum according to claim 10, wherein the plurality of slits extend parallel to each other in the cylindrical configuration of the underlay body.

12. The tire building drum according to claim 10, wherein the plurality of slits extend over at least half of the length of the underlay body between the first end and the second end.

13. The tire building drum according to claim 7, wherein the underlay body includes a plurality of bridge portions, each of the plurality of bridge portions interconnects a pair of the plurality of arm sections at the first end, and each bridge portion has a circumferential elasticity greater than the circumferential elasticity of the respective pair of arm sections being interconnected.

14. The tire building drum according to claim 13, wherein the underlay body has a first thickness in the plurality of arm sections and a second thickness smaller than the first thickness in the plurality of bridge portions.

15. The tire building drum according to claim 13, wherein the underlay body includes a different material in the plurality of bridge portions compared to the plurality of arm sections.

16. The tire building drum according to claim 13, wherein the underlay body includes layers of a different configuration in the plurality of bridge portions compared to the plurality of arm sections.

17. The underlay body includes a laminate of a first layer having a first elasticity and a second layer having a second elasticity greater than the first elasticity. The second layer is covered by the first layer in the plurality of arm sections and is exposed in the plurality of bridge portions. The tire building drum according to claim 13.

18. The underlay body is joined so as to form an annular configuration at the first end. The tire building drum according to any one of claims 7.

19. The underlay includes a plurality of arm sections extending separately from the first end toward a second end opposite to the first end. The tire building drum according to claim 2.

20. Each arm section of the plurality of arm sections extends along each pressing arm of the plurality of pressing arms and is configured to rest on each pressing arm. The tire building drum according to claim 19.

21. The underlay has a first end fixed to the drum body by one or more fasteners. The tire building drum according to claim 1.

22. The one or more fasteners include a group of fasteners including pins, bolts, clamps, or ridges. The tire building drum according to claim 21.

23. A method for turning up a tire component using the tire building drum according to claim 1, comprising: - Providing the underlay between the at least one hinge and the turn-up bladder in the radial direction; - Supporting the turn-up bladder on the underlay at the at least one hinge during the turn-up of the tire component. A method comprising the steps of.

Images