NL2027901B1

NL2027901B1 - Method for positioning a strip for splicing, gripper for supplying said strip for splicing and tire building machine comprising said gripper

Info

Publication number: NL2027901B1
Application number: NL2027901A
Authority: NL
Inventors: Marinus Van Beek Willem
Original assignee: Vmi Holland Bv
Priority date: 2021-04-01
Filing date: 2021-04-01
Publication date: 2022-10-17
Also published as: CN217455005U

Abstract

The invention relates to a method for positioning a strip for splicing, wherein the strip body has a first longitudinal side and a second longitudinal side, wherein the method comprises the steps of: a) stretching the second longitudinal side with respect to the first longitudinal side such that the second longitudinal side has excess length in the longitudinal direction with respect to a length of the first longitudinal side in said longitudinal direction; b) positioning the trailing end relative to the leading end for forming a butt—splice at said first longitudinal side; and c) positioning the trailing end relative to the leading end using the excess length at the second longitudinal side for forming an overlapping splice at said second longitudinal side. The invention further relates to a first gripper for supplying a strip for splicing and a tire building machine comprising said first gripper.

Description

P139608NLOO Method for positioning a strip for splicing, gripper for supplying said strip for splicing and tire building machine comprising said gripper

BACKGROUND The invention relates to a method for positioning a strip, in particular an apex strip, for splicing, a gripper for supplying said strip for splicing and a tire building machine comprising said gripper.

WO 2014/092558 Al discloses a tire building machine and method for forming a bead-apex assembly for tires. The machine comprises a first gripper and a second gripper for transporting the leading end and the trailing end, respectively, of an apex strip to a drum. The apex strip has a triangular cross section with a base portion and a tip portion opposite to the base portion. The apex strip is transported in a flat orientation towards the drum and spliced on said drum. After the splicing, the apex strip is flipped into an upright or radially outward orientation onto a bead at said drum.

SUMMARY OF THE INVENTION A disadvantage of the tire building machine and method known from WO 2014/092558 Al is that - although the length of the apex strip at the base portion remains substantially constant - the relatively thin tip portion of the apex strip tends to crimp, shrink or contract slightly directly after extrusion and/or prior to or during transport. Consequently, the leading end and the trailing end of the apex strip no longer have the same shape and/or be in the same orientation. The known grippers are configured for merely engaging and linearly transporting the leading end and the trailing end. A shorter length of the apex strip at the side of the tip portion will therefore inevitably result in an open splice rather than the desired butt-splice.

It is an object of the present invention to provide a method for positioning a strip, in particular an apex strip, for splicing, a gripper for supplying said strip for splicing and a tire building machine comprising said gripper, wherein the apex strip can be better prepared for splicing.

According to a first aspect, the invention provides a method for positioning a strip for splicing, wherein the strip has a strip body extending in a longitudinal direction between a leading end and a trailing end, wherein the strip body has a first longitudinal side and a second longitudinal side opposite to the first longitudinal side in a lateral direction perpendicular to the longitudinal direction, wherein the strip body is thicker at the first longitudinal side than at the second longitudinal side, wherein the method comprises the steps of: a) stretching the second longitudinal side with respect to the first longitudinal side such that the second longitudinal side has excess length in the longitudinal direction with respect to a length of the first longitudinal side in said longitudinal direction; b) positioning the trailing end relative to the leading end for forming a butt-splice at said first longitudinal side; and c} positioning the trailing end relative to the leading end using the excess length at the second longitudinal side for forming an overlapping splice at said second longitudinal side.

The leading end and the trailing end can subsequently be spliced.

A ‘butt-splice’ is a splice of the trailing end to the leading end in which the ends merely abut, without adding excess material to the splice. A butt-splice can be reliable when the leading end and the trailing end have a relatively large surface area to adhere to, i.e. when the strip is relatively thick. An ‘overlapping splice’ is a splice of the trailing end to the leading end in which the excess length of the strip causes the trailing end to extend at least partially beyond the leading end. Consequently, the trailing end not only adheres to the leading end, but also to the top of the strip beyond said leading end. An overlapping splice may result in a slight bulge of excess material on top of the strip at the location of the splice area. An overlapping splice can be more reliable than a butt-splice when the leading end has a relatively small surface area to adhere to the trailing end, i.e. when the strip is relatively thin.

In the method according to the present invention, the strip body at the second longitudinal side is relatively thin and tends to contract or shrink prior to splicing. To prevent an open splice at the second longitudinal side, the second longitudinal side is stretched. In fact, the second longitudinal side is not only stretched to close the splice, it is stretched even further to generate excess length generated at the second longitudinal side. The excess length allows for the formation of an overlapping splice at the second longitudinal side where the strip body is relatively thin and where said overlapping splice is considerably more reliable than a butt-splice. Because the strip body is relatively thin at the second longitudinal side, the excess material added by said overlapping splice is relatively small. Therefore, bulging - if any - can be kept to a minimum.

Meanwhile, at the relatively thick first longitudinal side, the leading end and the trailing end can still be butt- spliced. The butt-splice may progressively transition into an overlapping splice from the first longitudinal side towards the second longitudinal side. Consequently, a reliable splice can be formed across the entire width of the strip.

In a preferred embodiment, the strip body has a cross section perpendicular to the longitudinal direction that tapers from a base portion at the first longitudinal side to a tip portion at the second longitudinal side. More in particular, the cross section is triangular. This kind of cross section is typical for an apex strip or filler strip that is used in tire building to form an bead-apex of a tire.

Preferably, the stretching of step a) comprises the steps of: al) providing a first gripper with a gripper head; a?) engaging one of the leading end and the trailing end with the gripper head of said first gripper; and a3) rotating the gripper head of said first gripper about a correction axis perpendicular to the longitudinal direction and the lateral direction. By introducing a first gripper to engage one of the ends, the stretching of the second longitudinal side can be mechanized and/or automated.

The rotation about the correction axis allows for a stretching of at least a part of the strip at the second longitudinal side in a direction about said correction axis.

In particular, the correction axis is located at or near the first longitudinal side. Hence, the second longitudinal side can be stretched about the correction axis with respect to the first longitudinal side, whereas the effect of the rotation of the gripper head of the first gripper about the correction axis on the first longitudinal side can be minimized. More in particular, the correction axis is located at or near said one of the leading end and the trailing end. Hence, the effect of the rotation of the gripper head of the first gripper about the correction axis on the first longitudinal side at said one end can be minimized.

In another embodiment the correction axis remains stationary in the lateral direction. Hence, it can be prevented that the strip is deformed in the lateral direction when it is being held by the gripper head.

In a further embodiment the strip body has a strip width in the lateral direction between the first longitudinal side and the second longitudinal side, wherein the gripper head of the first gripper engages the strip body at or near said one of the leading end and the trailing end across the strip width in its entirety.

Consequently, the strip body can be manipulated as a whole across the entire strip width.

In 5 particular, as mentioned before, the strip body can be progressively stretched from the first longitudinal side towards the second longitudinal side.

In a further embodiment the length of the first longitudinal side remains constant or substantially constant during the rotation of the gripper head of the first gripper in step a3). In other words, the first longitudinal side remains unstretched, or at least unaffected by the gripper head of the rotation of the first gripper.

This does however not preclude that the first longitudinal side is stretched as a result of another operation, i.e. as part of the stretching of the strip as a whole, in the longitudinal direction.

Such stretching may be useful to keep the strip tensioned and/or to prevent slacking prior to the splicing.

In a further embodiment said one of the leading end and the trailing end is the leading end.

When gripping the leading end, the drive mechanism used to rotate the gripper head can be positioned downstream of said gripper head alongside at least a part of the strip or the conveyor supporting said grip.

Hence, less of the drive mechanism projects beyond the strip at trailing end, thereby providing a more compact configuration.

In a further embodiment the method further comprises the steps of: d) providing a second gripper; e) engaging the other of the leading end and the trailing end with the second gripper; wherein the first gripper and the second gripper are spaced apart in the longitudinal direction of the strip over a gripper distance, wherein the method further comprises the step of: f) increasing the gripper distance during step a). This allows for stretching of the strip as a whole in the longitudinal direction. Such stretching may be useful to keep the strip tensioned and/or to prevent slacking prior to the splicing.

In another embodiment the strip is wound into an annular configuration along a circular path prior to the positioning in steps b) and ¢), wherein the trailing end is positioned relative to the leading end in steps b) and c) by linearly moving said trailing end along an application path tangent to the circular path until the trailing end contacts the leading end. Conventionally, prior to splicing, the trailing end is lifted into a position well above the circular path until the trailing end is above the leading end at the splice area. The trailing end is subsequently lowered onto the leading end for splicing. The lifting and lowering of the trailing end unpredictably deforms and/or unintentionally stretches the strip, thereby reducing the quality of the splicing. By advancing the trailing end solely in a linear manner along the application path, any lifting or lowering of the trailing end relative to the circular path can be prevented. Instead, the movement of the leading end along the circular path can introduce a relative movement between the leading end and the trailing end in a radial direction with respect to the circular path, which relative movement allows for the trailing end to be applied on top of the leading end merely by completing the movements of the leading end and the trailing end along the circular path and the application path, respectively. According to a second aspect, the invention provides a first gripper for supplying a strip for splicing, wherein the strip has a strip body extending in a longitudinal direction between a leading end and a trailing end, wherein the first gripper comprises a base that is movable in a transport direction and a gripper head extending in a transport plane parallel to said transport direction for engaging one of the leading end and the trailing end in said transport plane, wherein the gripper head is rotatable relative to the base about a correction axis perpendicular

: to the transport plane.

The rotation about the correction axis allows for a stretching of at least a part of the strip at one of its longitudinal sides in a direction about said correction axis, with the same technical advantage as described in relation to the method according to the first aspect of the invention.

Preferably, the first gripper comprises a drive mechanism for driving the rotation of the gripper head about the correction axis. The drive mechanism can control the rotation of the gripper head and/or at least partially automate said rotation.

More preferably, the drive mechanism is configured for driving the rotation of the gripper head about a virtual hinge point on the correction axis, wherein the virtual hinge point is located outside of the drive mechanism. The effect of rotation of the gripper on the stretching of the strip will be minimal at the virtual hinge point and will increase further away from the virtual hinge point. Hence, the virtual hinge point can be conveniently located somewhere on or at the strip where the stretching effect is to be minimized. As already described in relation to the method, the correction axis is preferably located on the first longitudinal side of the strip, more preferably at one of the leading end and the trailing end engaged by the first gripper. The virtual hinge point may thus be positioned in accordance with this preference.

In a further embodiment the drive mechanism comprises a linkage. A linkage can be mechanically designed to rotate the gripper head about a virtual hinge point that is located outside of said linkage. Alternatively, other suitable drive mechanisms may be envisioned, not limited to but including actuators and/or robotic manipulators, which can be designed to rotate about a virtual hinge point as well. The technical advantage of the linkage is that this may be relatively low-tech, low-cost solution.

In a further embodiment the drive mechanism has a movement range, wherein the movement range is fixed. The drive mechanisms can thus be controlled in a simple manner between two extreme positions, without requiring adjustment and/or setup.

Alternatively, the drive mechanism has a movement range, wherein the movement range is variable. The movement range may be varied to adjust for differences in geometry or material characteristics of the strip. The movement range may be adjustable in one or more steps or it may be continuously adjustable.

According to a third aspect, the invention provides a tire building machine comprising the first gripper according to the second aspect of the invention, which therefore has the same technical advantages as said first gripper. Moreover, the tire building machine can be used to implement the method according to the first aspect of the invention.

Preferably, the tire building machine further comprises a drum that defines a circular path for receiving the strip in an annular configuration, wherein the first gripper is linearly movable along an application path tangent to the circular path up to an application position where the application path intersects with the circular path.

Alternatively or additionally, the tire building machine further comprises a drum that defines a circular path for receiving the strip in an annular configuration, wherein the first gripper is configured for engaging the leading end, wherein the tire building machine further comprises a second gripper for engaging the trailing end, wherein the second gripper is linearly movable along an application path tangent to the circular path up to an application position where the application path intersects with the circular path. By advancing the leading end and/or the trailing end solely in a linear manner along the application path, any lifting or lowering of said ends relative to the circular path can be prevented, thereby preventing unpredictable deformations in the strip and/or unintentional stretching of the strip.

In a further embodiment the drum is provided with a drum body and a recess in said drum body for receiving the first gripper and/or the second gripper. Hence, the first gripper and/or the second gripper can be at least partially received within the circular path to support the strip until the respective gripper is retracted from said recess, preferably in a direction parallel to a central axis of the drum body. 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 1-5 show top views of a tire building machine with a drum, a first gripper and a second gripper during the steps of a method for supplying a strip to the drum for splicing according to the invention; figure 6 shows a side view of the drum and the strip according to figures 1-5 during subsequent stages of the application and splicing of said strip around said drum; figure 7 shows a top view of strip at the area where the strip is spliced; figures 8 and 9 show cross sections of the splice area according to line VIII - VIII and line IX - IX, respectively, in figure 7; and figure 10 shows a front view of the first gripper according to figures 1-5.

DETAILED DESCRIPTION OF THE INVENTION Figures 1-5 show a tire building machine 1 for building a tire. The tire building machine 1 in this example is configured for preparing a strip 9, in particular an apex or an apex filler strip, for splicing. After the splicing, the strip 9 has an annular configuration. Such an apex filler strip is typically stitched to a bead to form a so-called ‘bead-apex’.

As best seen in figure 1, the strip 9 has a strip body 90 extending in a longitudinal direction X between a leading end LE and a trailing end TE. The strip body 90 is made from an elastomeric material, preferably rubber. The strip body 90 further has a first longitudinal edge or a first longitudinal side 91 and a second longitudinal edge or a second longitudinal side 92 opposite to the first longitudinal side 91 in a lateral direction Y perpendicular to the longitudinal direction X. The strip body 90 has a strip width W in the lateral direction Y between the first longitudinal side 91 and the second longitudinal side 92.

As shown in figure 10, the strip body 90 is thicker at the first longitudinal side 91 than at the second longitudinal side 92. In particular, the strip body 90 has a cross section perpendicular to the longitudinal direction X that tapers from a base portion 93 at the first longitudinal side 91 to a tip portion 94 at the second longitudinal side

92. More in particular, the cross section is triangular. The strip 9 is arranged in a flat, horizontal or substantially horizontal orientation. Alternatively formulated, the strip 9 is arranged in a landscape orientation, i.e. with one of the longer side of the triangular cross section extending horizontally or substantially horizontally.

As shown in figure 1, the tire building machine 1 comprises a drum 5 for receiving the strip 9 and a support surface 10 for supporting a strip 9 relative to said drum 5. As best seen in figure 6, the drum 5 has a cylindrical drum body 50 that is rotatable about a drum axis or central axis

S. The drum body 50 defines a circular path P for receiving the strip 9 in the aforementioned annular configuration.

The tire building machine 1 further comprises a first gripper 2 and a second gripper 3 for gripping, engaging and/or retaining the strip 9 at the leading end LE and the trailing end TE, respectively. Note that the first gripper 2 and the second gripper 3 may alternatively switch positions such that the first gripper 2 is responsible for engaging the trailing end TE and the second gripper 3 is responsible for engaging the leading end LE. The functionality of the first gripper 2 and the second gripper 3, which will be described in more detail hereafter, remains the same. Hence, any functionality described hereafter that involves the interaction between the first gripper 2 and the leading end LE, may also be applied, mutatis mutandis, to the trailing end TE.

The tire building machine 1 further comprises a first guide 11 and a second guide 12 for guiding and/or moving the first gripper 2 and the second gripper 3, respectively, in a transport direction B parallel or substantially parallel to the longitudinal direction X of the strip 9. The first guide 11 and the second guide 12 may for example be rails along which the respective grippers 2, 3 are movable. The first gripper 2 and the second gripper 3 are linearly movable in the transport direction B along an application path A. As shown in figure 6, the application path A is tangent or substantially tangent to the circular path P. In other words, the application path A intersects with the circular path P. More in particular, the application path A has the same direction as the circular path P at the point where both intersect.

As shown in figure 1, the first gripper 2 comprises a base 20 that is movable in the transport direction B along the first guide 11 and a gripper head 21 for engaging the leading end LE. The gripper head 21 extends in or parallel to a transport plane C that is parallel to the transport direction B, the longitudinal direction X and/or the lateral direction Y. The gripper head 21 is rotatable relative to the base 20 about a correction axis Z perpendicular to the transport plane C. The gripper head 21 is rotated as a whole, i.e. in its entirety. In this exemplary embodiment, the correction axis Z extends vertically or substantially vertically. Preferably, the correction axis Z is chosen such that it is located on, at or as close as possible to the first longitudinal side 91. More preferably, the correction axis Z is located at the leading end LE.

As shown in figures 2 and 3, the first gripper 2 comprises a drive mechanism 22 for driving the rotation of the gripper head 21 about the correction axis Z. The drive mechanism 22 is configured for driving the rotation of the gripper head 21 about a virtual hinge point V on the correction axis Z. Said virtual hinge point V is located outside of the drive mechanism 22. In this exemplary embodiment the drive mechanism 22 comprises a linkage 23, in particular a non-parallel four bar linkage designed to pivot about the virtual hinge point V. The movement of the linkage 23 is controlled by an actuator 24, for example a piston. The stroke of the actuator 24 defines the movement range of the drive mechanism 22. In this exemplary embodiment, the movement range is fixed. Hence, the drive mechanism can simply be operated within its mechanical boundaries. Alternatively, the movement range may be variable in one or more steps or continuously variable. The movement range may be varied manually, i.e. by an operator, or electronically. The movement range may further be set automatically, i.e. based on sensor input.

The drive mechanism 22 may be optimized to rotate about a fixed correction axis Z. However, there may be some small, acceptable tolerances that allow the drive mechanism 22 to rotate the gripper head 21 about the correction axis Z while the correction axis Z itself moves slightly in the longitudinal direction X and/or the lateral direction Y. Considering the relatively small angle of rotation, the effect of such movements will be neglectable.

Figure 10 shows the gripper head 21 of the first gripper 2 in more detail. Said gripper head 21 comprises a lower gripper member 25 and an upper gripper member 26 that can be moved towards and away from each other, like opposing Jaws, to engage the strip 9. In this exemplary embodiment, the lower gripper member 25 remains stationary at the transport plane C, while the upper gripper member 26 is moved down towards or upwards away from the lower gripper member

25. In other words, the strip 9 is not lifted from the transport plane C at any position along the application path A. The first gripper 2 preferably comprises one or more retaining elements 27 that can adapt to the shape and/or cross section of the strip 9 for a reliably engagement of the strip 9 across the entire strip width W thereof. In this example, the one or more retaining elements 27 are spring-biased fingers projecting from the upper gripper member 26 towards the lower gripper member 25. Alternatively, the upper gripper member 26 may be positioned at an appropriate angle to engage the strip body 90 uniformly along the entire strip width W.

The second gripper 3, like the first gripper 2, comprises a base 30. The base 30 of the second gripper 3 is movable in the transport direction B along the second guide

12. The second gripper 3 further comprises a gripper head 31 that, in this example, is similar in configuration to the gripper head 21 of the first gripper 2. Alternatively, the gripper head 31 of the second gripper 3 may be different in configuration. The gripper head 31 of the second gripper 3 is not rotatable with respect to the base 30 of the second gripper 3. In other words, the gripper head 31 of the second gripper 3 is fixed relative to the base 30 of the second gripper 3. Alternatively, the second gripper 3 may be provided with a drive mechanism similar to the drive mechanism 22 of the first gripper 2 to allow for a similar rotation of the gripper head 31 of the second gripper 3, for example when both the leading end LE and the trailing end TE require correction.

As best seen in figure 6, the drum 5 is provided with a strategically positioned recess 51 in the drum body 50 for at least partially receiving the first gripper 2 and/or the second gripper 3 when said respective gripper 2, 3 arrives in the application position. Hence, both the leading end LE and the trailing end TE can be applied to the drum 5 while being retained by the respective gripper 2, 3 as long as possible. The respective gripper 2, 3, once disengaged from the strip 9, can be retracted from said recess 51 in a direction parallel or substantially to the central axis S. A method for positioning the strip 9 for splicing with the use of the aforementioned tire building machine 1 will now be described in more detail with reference to figures 1-10.

Figure 1 shows the situation in which the strip 3 has been supplied to the support surface 10 of the tire building machine 1. The leading end LE has not vet been engaged by the first gripper 2. The trailing end TE may already be engaged by the second gripper 3, or it has not yet been engaged, like the leading end LE. The gripper head 21 of the first gripper 2 and the gripper head 31 of the second gripper 3 are spaced apart over a gripper distance G in the transport direction B. The leading end LE has shrunk at the second longitudinal side 92. Hence, the second longitudinal side 92 has a length that is shorter than the length of the first longitudinal side 91. When the trailing end TE is spliced to the leading end LE ‘as is’, then the splicing would result in an open splice at the second longitudinal side 92. Figure 2 shows the situation in which the drive mechanism 22 of the first gripper 2 is operated or controlled to rotate the gripper head 21 of the first gripper 2 about the virtual hinge point V into an orientation in which the gripper head 21 of the first gripper 2 is tilted at the second longitudinal side 92 in the same direction in which said second longitudinal side 92 has shrunk, i.e. in a direction opposite to the transport direction B. It is not essential for the gripper head 21 of the first gripper 2 to assume this tilted orientation. The steps discussed hereafter can also be performed when starting from the orientation as shown in figure 1. The tilted orientation allows for the gripper head 21 of the second gripper 2 to visually assume the same or substantially the same orientation as the leading end LE, i.e. extending parallel or substantially parallel to said leading end LE.

Either starting from the original orientation in figure 1 or the tilted orientation in figure 2, the gripper head 21 of the first gripper 2 is operated or controlled to engage the leading end LE. The second gripper 3 is also operated or controlled to engage the trailing end TE, if this has not been done so already. Hence, both ends LE, TE of the strip 9 have now been securely engaged and can be manipulated and/or transported by the respective grippers 2, 3.

Figure 3 shows the situation in which the gripper head 21 of the second gripper 2 has been rotated about the correction axis Z and/or the virtual hinge point V in a direction with at least a component in the transport direction B to stretch the second longitudinal side 92 with respect to the first longitudinal side 91. When starting from the tilted orientation of figure 2, the gripper head 21 of the first gripper 2 can be returned to the original position of figure

1. When starting from the original orientation of figure 1, the gripper head 21 of the first gripper 2 is rotated as far about the correction axis Z and/or the virtual hinge point V as required for the aforementioned stretching.

In this exemplary embodiment, the gripper head 21 is rotated further than required for closing the splice at the second longitudinal side 92. In particular, the second longitudinal side 92 is stretched with respect to the first longitudinal side 91 such that the second longitudinal side 92 has overlength or excess length D, as shown in figure 3, in the longitudinal direction X with respect to a length of the first longitudinal side 91 in said longitudinal direction X. In other words, the second longitudinal side 92 is stretched to a length that is longer than or exceeds the length of the first longitudinal side 91 with the excess length D. As a result of the stretching, the leading end LE is not arranged at a same angle as the trailing end TE. Instead, as shown in figure 7, the leading end LE, at the second longitudinal side 92, is tilted towards the drum 5 at an excess angle H of a few degrees, i.e. less than five degrees and preferably less than three degrees about the correction axis Z beyond the position of the trailing end TE at said second longitudinal side 92. In this particular example, the trailing end TE extends perpendicular or substantially perpendicular to the longitudinal direction X. Alternatively, the trailing end TE may extend obliquely to the longitudinal direction X.

Figure 4 shows the situation in which both grippers 2, 3 are moved simultaneously in the transport direction B towards the drum 5. During the movement of both grippers 2, 3 towards the drum 5, the gripper distance G may be increased slightly. This allows for stretching of the strip 9 as a whole in the longitudinal direction X. Such stretching may be useful to keep the strip 9 tensioned and/or to prevent slacking of the strip 9 prior to the splicing.

Note that the stretching as previously discussed in relation to figure 3 may also be combined with the movement of both grippers 2, 3 towards the drum 5 in figure 4, to save time. In other words, the strip 9 may be simultaneously subjected to a stretching of the second longitudinal side 92 with respect to the first longitudinal side 91 and a stretching of the strip 9 as a whole.

Figure 5 shows the situation in which the first gripper 2 has transferred the leading end LE of the strip 32 to the drum 5 and has disengaged from said leading end LE. The first gripper 2 may subsequently be retracted in a direction parallel or substantially parallel to the central axis S, i.e. to a background position. In said background position, the first gripper 2 can be returned to its start position of figure 1, in a manner known per se, without interfering with the operation of the second gripper 3. The second gripper 3 has been moved along its respective guide

12 to supply the trailing end TE to the drum 5 until the trailing end TE is positioned against and/or on the leading end LE. Both grippers 2, 3 are linearly movable along the application path A, that intersects with the circular path P at the drum 5, as shown in figure 6. More specifically, figure 6 shows the leading end LE and the trailing end TE, in dashed lines, in various stages of approach prior to the positioning for splicing. By advancing the trailing end TE solely in a linear manner along the application path A, any lifting or lowering of the trailing end TE relative to the circular path P can be prevented. Instead, the movement of the leading end LE along the circular path P can introduce a relative movement between the leading end LE and the trailing end TE in a radial direction with respect to the circular path P. Said relative movement allows for the trailing end TE to be applied on top of the leading end LE merely by completing the movements of the leading end LE and the trailing end TE along the circular path P and the application path A, respectively.

The second gripper 3 can be retracted from the recess 51 in the drum 5 in a direction parallel or substantially parallel to the central axis S.

Figures 7, 8 and 9 show the relative position between the leading end LE and the trailing end TE resulting from the aforementioned steps of the method. Figure 7 shows the leading end LE in dashed lines underneath the trailing end TE in solid lines, extending under the excess angle H with respect to the orientation of the trailing end TE. Consequently, the leading end LE, at the second longitudinal side 92 extends beyond the trailing end TE over the excess distance D. The excess distance D increases progressively or linearly from zero at the first longitudinal side 91 to the full excess distance D at the second longitudinal side 92. In other words, the first longitudinal side 91 is not stretched as a result of the rotation of the gripper head 21 of the first gripper 2 and the rest of the leading end LE is progressively stretched before reaching the full excess distance D at the second longitudinal side 92. As shown in the cross section of figure 8, taken at or near the first longitudinal side 91, the trailing end TE is positioned or placed relative to or against the leading end LE for forming a butt-splice. Meanwhile, as shown in the cross section of figure 9, taken at or near the second longitudinal side 92, the trailing end TE is positioned or placed relative to or on the leading end LE using the excess length D at the second longitudinal side 92 for forming an overlapping splice. The leading end LE and the trailing end TE are now ready to be spliced. 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.

LIST OF REFERENCE NUMERALS 1 tire building machine 10 support surface 11 first guide 12 second guide 2 first gripper 20 base 21 gripper head 22 drive mechanism 23 linkage 24 actuator 25 lower gripper member 26 upper gripper member 27 retaining element 3 second gripper 30 base

31 gripper head drum 50 drum body 51 recess

5 8 strip 90 strip body 91 first longitudinal side 92 second longitudinal side 93 base portion

94 tip portion A application path B transport direction C transport plane D excess length

G gripper distance H excess angle LE leading end P circular path S central axis

TE trailing end V virtual hinge point W strip width x longitudinal direction Y lateral direction

Z correction axis

Claims

CONCLUSIONS

A method of positioning a strip (9) for splicing, wherein the strip (9) has a strip body (90) extending in a longitudinal direction (X) between a leading end (LE) and a trailing end ( TE), wherein the strip body (90) has a first longitudinal side (91) and a second longitudinal side (92) opposite to the first longitudinal side (91) in a lateral direction (Y) perpendicular to the longitudinal direction (X), wherein the strip body ( 90) is thicker on the first longitudinal side {91} than on the second longitudinal side (92), the method comprising the steps of: a) stretching the second longitudinal side (92) relative to the first longitudinal side (91) such that the second longitudinal side (92) has excess length (D) in the longitudinal direction (X) with respect to a length of the first longitudinal side (91) in the longitudinal direction (X); b) positioning the trailing end (TE) relative to the leading end (LE) to form a butt splice at the first longitudinal side (91); and c) positioning the trailing end (TE) relative to the leading end (LE) using the excess length (D) at the second longitudinal side (92) to form an overlapping splice at the second longitudinal side (92 ).

The method of claim 1, wherein the strip body (90) has a cross-section perpendicular to the longitudinal direction (X) tapering from a base portion (93) at the first longitudinal side (91) to a tip portion (94) at the second longitudinal side ( 92).

The method of claim 2, wherein the cross-section is triangular.

A method according to any one of the preceding claims, wherein the strip (9) is an apex strip.

A method according to any one of the preceding claims, wherein the stretching according to step a) comprises the steps of: a1) providing a first gripper (2) having a gripping head (21); a2) engaging one of the leading end (LE) and towards the trailing end (TE) with the gripping head (21) of the first gripper (2); and a3) rotating the gripping head (21) of the first gripper (2) about a correction axis (Z) perpendicular to the longitudinal direction (X) and the lateral direction (Y).

The method of claim 5, wherein the correction axis (Z) is located at or near the first longitudinal side (91).

The method of claim 6, wherein the correction axis (Z) is located at or near one of the leading end (LE) and the trailing end (TE).

A method according to any one of claims 5-7, wherein the correction axis (Z}) remains stationary in the lateral direction (Y).

A method according to any one of claims 5-8, wherein the strip body (90) has a strip width (W) in the lateral direction (Y) between the first longitudinal side (91) and the second longitudinal side (92), the gripping head (21 ) of the first gripper (2) engages the strip body (90) at or near one of the leading end (LE) and the trailing end (TE) over the entire strip width (W).

A method according to any one of claims 5-9, wherein the length of the first longitudinal side (91) remains constant or substantially constant during the rotation of the gripping head (21) of the first gripper (2) in step a3).

A method according to any one of claims 5-10, wherein the at least one of the leading end (TE) and the trailing end (TE) is the leading end (LE).

The method of any one of claims 5-11, wherein the method further comprises the steps of:

d) providing a second gripper (3); e) engaging the other of the leading end (LE) and the trailing end (TE) with the second gripper (3); wherein the first gripper (2) and the second gripper (3) are spaced apart in the longitudinal direction (X) of the strip by a gripping distance (G), the method further comprising the steps of: f) increasing of the gripping distance (G) during step a}.

A method according to any one of the preceding claims, wherein the strip (9) is wound into an annular configuration along a circular path (P) prior to positioning in steps b) and Cc).

A method according to claim 13, wherein the trailing flared end (TE) is positioned with respect to the leading end (LE) in steps Db) and ¢) by linearly moving the trailing tail (TE) along an application path (A). tangentially to the circular track (P) until the trailing end (TE) contacts the leading end (LE).

15. First gripper (2) for supplying a strip (9) for splicing, the strip (9) having a strip body (90) extending in a longitudinal direction (X) between a leading end (LE) and a trailing end end (TE), the first gripper (2) comprising a base (20) movable in a conveying direction (B) and a gripping head (21) extending in a conveying plane (C) parallel to the conveying direction (B) for engaging one of the leading end (LE) and the trailing end (TE) in the conveying plane (C), the gripping head (21) being rotatable relative to the base (20) about a correction axis (2) perpendicular to the transport plane (C).

The first gripper (2) according to claim 15, wherein the first gripper (2) comprises a drive mechanism (22) for driving the rotation of the gripper head (21) about the correction axis (Z).

The first gripper (2) according to claim 16, wherein the drive mechanism (22) is configured to drive rotation of the gripper head (21) about a virtual pivot point (V) on the correction axis (2), wherein the virtual pivot point ( V) is located outside the drive mechanism (22).

The first gripper (2) according to claim 16 or 17, wherein the drive mechanism (22) comprises a rod mechanism (23).

The first gripper (2) according to any one of claims 17-18, wherein the drive mechanism (22) has a range of motion, the range of motion being fixed.

The first gripper (2) according to any one of claims 16-18, wherein the drive mechanism (22) has a range of motion, the range of motion being variable.

Tire building machine (1) comprising the first gripper (2) according to any one of claims 15-20.

The tire building machine (1) according to claim 21, wherein the tire building machine (1) further comprises a drum (5) defining a circular path (P) for receiving the strip (9) in an annular configuration, the first gripper ( 2) is linearly movable along an application path (A) tangential to the circular path (P) up to an application position where the application path (A) intersects with the circular path (P).

The tire building machine according to claim 21, wherein the tire building machine further comprises a drum (5) defining a circular path (P) for receiving the strip (9) in an annular configuration, the first gripper (2) being configured to engaging the leading end (LE), the tire building machine (1) further comprising a second gripper (3) for engaging the trailing end (TE), the second gripper (3) being linearly movable along an application path (A) tangential to the circular path (P) until an application position where the application path (a) intersects with the circular path (P).

Tire building machine (1) according to claim 22 or 23, wherein the drum (5) is provided with a drum body (50) and a recess (51) in the drum body (50) for receiving the first gripper (2) and/ or the second gripper (3). -070-0-0-0-0-0-0-