Gripper and method for gripping a tire bead

Abstract

The present invention relates to a gripper for gripping a tire bead to be transferred from a picking position to a placing position, the gripper (1) comprising: two or more engagement claws (12) arranged on the gripper at equal angular distances in a circumferential direction, wherein each of the two or more engagement claws (12) is provided with an engagement finger (13) for engaging the tire bead (2) to be gripped, wherein the engagement claws are configured to be moved radially between a remote position, in which the engagement finger (13) is remote from the tire bead to be gripped, and an engagement position, in which the engagement finger engages the tire bead to be gripped, wherein the gripper is provided with an ejection finger (35) configured for ejecting the tire bead gripped by the gripper from the gripper.

Description

TECHNICAL FIELD

[0001] The present invention relates to a gripper for gripping a tire bead ring to be transferred from a pickup position to a placement position. Furthermore, the present invention relates to a method for gripping a tire bead ring to be transferred from a pickup position to a placement position, and to a bead transfer device for transferring a tire bead ring from a pickup position to a placement position. BACKGROUND

[0002] Such a gripper is known, for example, from the international patent publication WO 2010 / 021546, which describes a device for transferring and placing tire beads, which device is provided, inter alia, with a bead holding device for picking up and holding a bead, wherein the bead holding device is provided with engagement claws which are arranged on the bead holding device at equal angular distances in the circumferential direction, wherein the engagement claws can be driven or retracted in the radial direction in order to engage or release the tire bead, respectively. SUMMARY

[0003] The known gripper is used, inter alia, for retrieving a tire bead ring from a tire bead-tread band assembly drum and placing the retrieved tire bead ring onto a next position, such as a stack of tire bead rings. The tire bead ring is picked up by driving the engagement claws radially outwardly such that the tire bead ring is engaged by the engagement claws, and placed onto the tire bead-tread band assembly drum by driving the engagement claws radially inwardly to release the tire bead ring from the gripper. All engagement claws are driven simultaneously, such that the engagement claws are moved simultaneously. It is important that the placement onto the next position is performed centrally and uniformly. In order to obtain a good adhesion of the tire bead ring to the tread band, the tire bead ring is provided with a thin layer of unvulcanized rubber. Due to the thin layer of unvulcanized rubber, the tire bead ring can remain stuck to one engagement claw when the engagement claws are moved inwardly. This is disadvantageous, because it results in that the tire bead ring cannot be released from all engagement claws simultaneously, and thus the placement of the tire bead ring onto the tire bead-tread band assembly drum cannot be performed centrally. In addition, the tire bead ring can be disadvantageously deformed into a non-circular shape due to remaining stuck to one engagement claw.

[0004] It is an object of the present invention to improve or eliminate one or more of the drawbacks of the known prior art, to provide an improved gripper or at least to provide an alternative gripper.

[0005] According to a first aspect, the present invention provides a gripper for gripping a tire bead ring to be transferred from a pickup position to a placement position, the gripper comprising:

[0006] two or more engagement claws arranged on the gripper at equal angular distances in the circumferential direction, wherein each of the two or more engagement claws is provided with an engagement finger for engaging the tire bead ring to be gripped,

[0007] wherein the engagement claws are configured to move radially between a remote position, in which the engagement fingers are distanced from a tyre bead to be gripped, and an engagement position, in which the engagement fingers engage the tyre bead to be gripped,

[0008] wherein the gripper is provided with an ejection finger configured for ejecting a tyre bead gripped by the gripper from the gripper.

[0009] During use of the gripper according to the application, the engagement fingers are moved from a remote position, such as a radially inward position, to an engagement position, such as a radially outward position, in order to engage and thereby grip a tyre bead. When the gripper is close to or in the deposit position, the engagement fingers are moved radially inward to release the gripper tyre bead from the gripper. Prior to or during the radially inward movement of the engagement fingers to release the gripped tyre bead, the ejection finger will exert an ejection force on the tyre bead. When the engagement fingers are moved radially inward, the ejection force exerted by the ejection finger prevents the tyre bead from remaining stuck to one or more engagement fingers. This is advantageous because the release of the tyre bead from all engagement fingers at the same time is performed centrally and uniformly.

[0010] In one embodiment, the ejection finger is configured for ejecting a tyre bead gripped by the gripper from the gripper in an ejection direction, which is transverse to the movement direction and is directed away from the gripper. For example, when the gripper has a horizontal orientation such that the engagement claws move in a horizontal direction, the ejection finger is configured for ejecting the gripper tyre bead in a vertically downward directed direction.

[0011] In one embodiment, the gripper comprises two or more ejection fingers, wherein each of the two or more engagement claws comprises an ejection finger. By arranging the ejection finger at the engagement claw, the ejection finger advantageously acts on the gripped tyre bead at a position closest to the position at which the tyre bead can remain stuck.

[0012] In one embodiment, the ejector finger is configured to move between an idle position, in which the ejector finger is spaced apart from the tire bead, an ejecting position, in which the ejector finger abuts against the tire bead, thereby exerting an ejecting force onto the tire bead, and an ejected position, in which the ejector finger is at least partially positioned at the location at which the tire bead is located. In one embodiment thereof, the ejector finger is configured to move into the ejecting position when the associated engagement finger is in the engagement position. According to this embodiment, the ejector finger moves into the ejecting position before the associated engagement finger moves out of the engagement position and towards the remote position. In the ejecting position, the ejector finger rests against the tire bead such that the ejecting force is exerted on the tire bead. Due to the ejecting force, there is a friction in the radial direction between the ejector finger and the tire bead. The inventors have surprisingly found that the ejecting force exerted on the tire bead and the radial friction associated therewith are sufficient to prevent the tire bead from remaining stuck to the engagement finger. Thus, enabling the gripper according to this embodiment to release the tire bead from all engagement claws simultaneously.

[0013] In an alternative embodiment, the ejector finger is configured to move into the ejecting position when initiating the movement of the associated engagement finger from the engagement position to the remote position.

[0014] In one embodiment, the engagement finger is configured to move from the remote position to the engagement position at a first speed and to move from the engagement position to the remote position at a second speed, wherein the second speed is higher than the first speed.

[0015] In one embodiment, each engagement claw comprises a separation finger configured for separating the tire bead to be gripped from the surface on which the tire bead is located and for moving between the remote position and the engagement position. In one embodiment thereof, each separation finger is provided with a tapered tip which is arranged in such a way that the tapered tip extends radially beyond the associated engagement finger when the separation finger and the associated engagement finger are in the engagement position. The separation finger with the tapered tip advantageously allows the gripper to prevent the tire bead from slipping off the engagement finger, for example during moving the tire bead to be gripped away from the surface on which it is located.

[0016] In one embodiment, the engagement finger and the disengagement finger of each engagement claw are operatively connected to each other such that movement of the disengagement finger from the remote position to the engagement position causes movement of the engagement finger from the remote position to the engagement position and such that the disengagement finger can be moved from the engagement position towards the remote position independently of the engagement finger. Preferably, the gripper comprises a drive configured for moving one or more engagement claws between the remote position and the engagement position. In one embodiment thereof, the drive is operatively connected to the respective disengagement finger of the one or more engagement claws. This embodiment is advantageous in that a single drive suffices to move the engagement finger and the disengagement finger from the remote position to the engagement position for at least each engagement claw or possibly each gripper.

[0017] In a further embodiment, the engagement finger of each engagement claw comprises a brake movable between an idle position in which the engagement finger is enabled to move between the remote position and the engagement position and a braking position in which the engagement finger is prevented from moving between the remote position and the engagement position. In a further embodiment, a spring is operatively connected to the engagement finger and the disengagement finger of each engagement claw and arranged between the engagement finger and the disengagement finger. According to this embodiment, the engagement finger can be maintained in the engagement position while the associated disengagement finger has been moved towards the remote position such that the conical tip is cleared before releasing the tire bead. Subsequently, when the brake of each engagement finger is moved from the braking position into the idle position, each engagement finger is pulled relatively quickly to the associated disengagement finger by means of the spring arranged between the engagement finger and the associated disengagement finger.

[0018] In one embodiment, the ejection finger of each engagement claw is arranged at the disengagement finger such that the ejection finger extends in a direction parallel to the direction of movement. In one embodiment thereof, the ejection finger is arranged at the disengagement finger which is rotatable about a rotation axis transverse to the direction of movement. According to this embodiment, the ejection finger works like a fin. This is advantageous in that the height required to incorporate the ejection finger into the gripper is kept to a minimum.

[0019] According to a second aspect, the application provides a method for gripping a tire bead to be transferred from a pick-up position to a drop-off position by means of a gripper according to the first aspect of the application, wherein the method comprises the following steps:

[0020] - moving the gripper towards the pick-up position when the engagement finger is in the remote position;

[0021] - moving the engagement finger radially into the engagement position thereby engaging the tire bead;

[0022] - moving the gripper towards the drop-off position; and

[0023] - releasing the gripped tire bead by moving the engagement finger towards the remote position,

[0024] wherein the method further comprises a step of ejecting the tyre bead from the gripper by means of the ejector finger of each engagement claw.

[0025] In an embodiment, wherein the ejector finger is configured to move between an idle position in which the ejector finger is spaced apart from the tyre bead, an ejection position in which the ejector finger abuts against the tyre bead so as to exert an ejection force onto the tyre bead, and an ejected position in which the ejector finger is at least partially positioned at a position at which the tyre bead is located, the step of ejecting the tyre bead comprises moving the ejector finger from the idle position to the ejection position and allowing the ejector finger to move into the ejected position. In an embodiment thereof, the step of moving the ejector finger from the idle position to the ejection position is performed prior to the step of releasing the gripped tyre bead.

[0026] In an alternative embodiment, the step of moving the ejector finger from the idle position to the ejection position is performed simultaneously with the step of releasing the gripped tyre bead.

[0027] In an embodiment, when the gripper is a gripper in which the engagement finger of each engagement claw comprises a detent movable between an idle position in which the engagement finger is enabled to move between the remote position and the engagement position, and a detent position in which the engagement finger is prevented from moving between the remote position and the engagement position, for each engagement claw, the step of moving the engagement finger into the engagement position comprises moving the disengagement finger into the engagement position so as to move the associated engagement finger into the engagement position, and moving the detent into the detent position when the disengagement finger and the associated engagement finger are in the engagement position.

[0028] In an embodiment, the method further comprises, for each engagement claw, moving the disengagement finger out of the engagement position towards the remote position when the detent of the associated engagement finger is moved into the detent position.

[0029] In an embodiment, wherein the gripper is a gripper in which a spring is operatively connected to the engagement finger and the disengagement finger of each engagement claw and disposed between the engagement finger and the disengagement finger, the step of releasing the gripped tyre bead by moving the engagement finger towards the remote position comprises moving the detent into the idle position.

[0030] According to a third aspect, the application provides a bead transfer device for transferring a tyre bead from a pick-up position to a deposit position, the bead transfer device comprising:

[0031] a robot arm and a gripper according to the first aspect of the application, the gripper being arranged at the robot arm so that the robot arm can move the gripper.

[0032] According to a fourth aspect, the present invention provides a computer-readable medium having computer-executable instructions adapted to cause a gripper according to a first aspect of the invention to perform a method according to a second aspect of the invention.

[0033] Whenever possible, the various aspects and features described and illustrated in the specification may be applied individually. These individual aspects, especially those described in the appended dependent claims, may serve as the subject matter of a divisional patent application. Attached Figure Description

[0034] The invention will be explained based on exemplary embodiments shown in the schematic drawings, in which:

[0035] Figure 1 A bead transfer device for transferring a tire bead from a pickup position to a placement position is shown, the bead transfer device including a gripper according to an embodiment of the invention;

[0036] Figure 2 It shows Figure 1 An enlarged side view of the gripper; and

[0037] Figures 3A to 3E It shows the use of Figure 2 The steps for the gripper to pick up and place the tire wire ring. Detailed Implementation

[0038] Figure 1 The diagram schematically illustrates a bead transfer device 50 configured to transfer the tire bead 2 from a pick-up position to a placement position. The bead transfer device 50 includes a gripper 1 according to an embodiment of the invention. The bead transfer device 50 can be used, for example, to transfer the tire bead 2 from a forming drum to a bead separator, wherein the tire bead 2 can be picked up vertically from the forming drum and placed horizontally onto the bead separator.

[0039] like Figure 1 As shown, the tire bead transfer device 50 is equipped with a robotic arm 51 for engaging the tire bead 2 and transporting it from a pick-up position to a placement position. The robotic arm 51 is supported by a robotic arm base 52, for example, fixed relative to the factory floor 53. The robotic arm 51 has a robotic arm 54 supported by the robotic arm base 52, and a gripper 1 arranged at the robotic arm 54, particularly at the end of the robotic arm 54 opposite to the robotic arm base 52. The robotic arm 54 typically provides six degrees of freedom to the robotic arm 51, thereby enabling the tire bead transfer device 50 to pick up the tire bead 2 vertically and place it horizontally, or vice versa.

[0040] Figure 2A detailed side view of the gripper 1 is shown in Fig. 1. The gripper 1 has a gripper frame 10 with a gripper connector 11 for connecting the gripper 1 to a robot arm 54. The gripper connector 11 extends substantially transversely or transversely to the gripper frame 10 and defines a central axis C running through the gripper connector 11 and transversely to the gripper frame 10. The gripper frame 10 can be formed, for example, by four not shown arms extending radially outward from the center of the gripper frame 10. Such a configuration of the gripper frame is shown, for example, in the international patent publication WO 2010 / 021546 of the applicant.

[0041] In order to grip a tire bead 2 with the gripper 1, the gripper 1 is provided with two or more, in this example four, engagement claws 12. The engagement claws 12 are arranged at equal angular distances in the circumferential direction on the gripper 1, so that according to the shown example there is an angular distance of 90° between adjacent engagement claws 12. Furthermore, the engagement claws 12 are arranged movable at the gripper frame 10. The engagement claws 12 are configured to move mainly radially outward (as seen from the center line C) and transversely to the center line C and in the direction of movement M in order to engage the tire bead 2 and to move radially inward in order to release the tire bead 2 from the gripper 1.

[0042] In an alternative embodiment, not shown, the engagement claws 12 can be configured to move mainly radially inward (as seen from the center line C) and transversely to the center line C and in the direction of movement M in order to engage the tire bead 2 and to move radially outward in order to release the tire bead 2 from the gripper 1.

[0043] As Figure 2 As shown schematically, each engagement claw 12 comprises an engagement finger 13 for engaging the tire bead 2 to be gripped. The engagement finger 13 is arranged movable to the gripper frame 10 by means of a first connector 14, so that the engagement finger 13 can be moved linearly relative to the gripper frame 10. For example, the engagement finger 13 is connected to not shown guide rails at the gripper frame 10. The engagement finger 13 further comprises an engagement body 15 connected to the first connector 14, having a radially outwardly facing engagement face 16 for engaging the tire bead 2 to be gripped by the gripper 1.

[0044] Each engagement finger 13 comprises a receiving slit 17 having a longitudinal axis parallel to the direction of movement M and extending at least partially through the engagement finger 13 in a direction transversely to the direction of movement M and the center line C. As Figure 2 As is clearly shown in Fig. 1, the length of the receiving slit 17 is smaller than the length of the engagement body 15 in the direction of movement M and, preferably, the receiving slit 17 is located within the inwardly pointing half of the engagement body 15. Furthermore, each engagement finger 13 is provided on the side facing the gripper frame 10 with a brake 18, which is movable in a braking direction B parallel to the center line C in the direction of movement M and in the opposite direction.Figure 2 is shown between the idle position and the braking position in which the brake 18 is in braking contact with the gripper frame 10.

[0045] As Figure 2 is shown, each engagement claw 12 also comprises a separating finger 25 which is configured for separating the tyre bead 2 to be gripped, for example from any further tyre bead 2 on the stack of tyre beads 2, or from the surface on which the tyre bead 2 is placed. The separating finger 25 is movably connected to the gripper frame 10 by means of a second connector 26, for example to a not shown guide rail. In addition, the separating finger 25 is operatively connected to a not shown drive, for example a servo motor or a drive cylinder, which is configured for driving the separating finger 25 in a radial outward or radial inward movement direction M. In this exemplary embodiment, the separating finger 25 is arranged adjacent to the engagement finger 13 of the respective engagement claw 12.

[0046] Each separating finger 25 has a connection portion 27 which, in this exemplary embodiment, is rectangular when viewed from the side. The second connector 26 is arranged at the connection portion 27, in particular at a side thereof facing the gripper frame 10. On a side of the connection portion 27 facing the engagement finger 13, the connection portion 27 is provided with a connection pin 28 extending away therefrom and towards the engagement finger 13. The connection pin 28 is received within the receiving slit 17 of the adjacent engagement finger 13, such that a movement of the separating finger 25 causes a movement of the engagement finger 13 when the connection pin 28 abuts against one end of the receiving slit 17.

[0047] In an alternative embodiment, each separating finger 25 is provided with a receiving slit 17 and each engagement finger 13 is provided with a connection pin 28.

[0048] Each separating finger 25 also has a separating portion 29 arranged at the connection portion 27, in particular at a side thereof facing radially outward. The separating portion 29 extends radially outward from the connection portion 27 and is at least in this exemplary embodiment elliptical. At an end of the separating portion 29 facing away from the connection portion 27, the separating portion 29 has a tapered tip 30 which can be positioned underneath the tyre bead 2 to be gripped. The separating finger 25 is intended to separate the tyre bead 2 to be gripped from the surface on which the tyre bead 2 is placed, for example in the event that the tyre bead 2 or the apex rubber attached to the tyre bead 2 remains stuck to this surface.

[0049] The length of the separating portion 29 and the length of the receiving slit 17 are chosen such that, when the separating finger 25 is in the engagement position, in this exemplary embodiment the radially outward position, i.e. with the connection pin 28 abutting against the radially outward end of the receiving slit 17, as Figure 2As shown, the conical tip 30 radially extends beyond the joint face 16 and, when the release finger 25 is in the remote position, in this exemplary embodiment a radially inward position, i.e. the connection pin 28 abuts or is close to the radially inward end of the receiving slit 17, the conical tip 30 is retracted in the radial direction such that the conical tip 30 does not radially extend beyond the joint face 16.

[0050] A spring 31 is provided between the release finger 25 and the joint finger 13 of each joint claw 12 and is operatively connected to the release finger 25 and the joint finger 13.

[0051] Furthermore, each joint claw 12 comprises an ejecting finger 35, also referred to as a fin, which is configured for ejecting the tire bead 2 held by the gripper 1 from the gripper 1. The ejecting finger 35 is configured for ejecting the tire bead 2 in an ejecting direction E transverse to the movement direction M of the joint finger 13, in particular in a direction parallel to the central axis C. The ejecting finger 35 has an elongated ejecting body 36 having a first end 37 and a second end 38 opposite the first end 37 when viewed in the longitudinal direction of the ejecting body 36. At its first end 37, the ejecting body 36 is rotatably connected to the release finger 25, in particular to the connection portion 27 thereof, on or adjacent to the side facing the gripper frame 1, wherein the ejecting finger 35 is rotatable about a rotation axis A. Thereby, movement of the release finger 25 causes movement of the ejecting finger 35. The second end 38 of the ejecting finger 35 is configured for approaching and / or contacting the tire bead 2 while ejecting the tire bead 2 from the gripper 1. The length of the ejecting body 36 is chosen such that the second end 38 of the ejecting body 36 radially extends beyond the joint face 16, regardless of the position of the release finger 25 relative to the joint finger 13.

[0052] As Figure 2 As best shown in Figure 2 As best shown in Figure 3D As best shown in

[0053] In an alternative embodiment, the ejecting finger 35 can be formed as an ejecting piston or an ejecting pusher.

[0054] Figures 3A to 3E is schematically shown in Figure 2The shown gripper 1 picks up and places a tire bead 2. When the gripper 1 is required to grip a tire bead 2, the gripper 1 is moved to a pick-up position, in which the engagement claw 12 is located within the tire bead 2, as shown in Figure 3A During this step, the engagement claw 12 is located in a radially inward position, as shown in Figure 3A In this radially inward position, the engagement claw 12 is spaced apart from the tire bead 2.

[0055] Subsequently, the engagement claw 12, in particular its separating finger 25, is moved to a radially outward position, as shown in Figure 3B In the shown exemplary embodiment, the separating finger 25 is moved radially outward and, due to the connecting pin 28 within the receiving slit 17, the engagement finger 13 is pulled. When in the radially outward position, the engagement face 16 of the engagement finger 13 engages the tire bead 2 and, optionally, the engagement claw 12 slightly stretches the tire bead 12 in order to prevent the tire bead 2 from slipping relative to the engagement face 16. Once the tire bead 2 is engaged by the engagement claw 12 and thereby gripped, the gripper 1 can move the gripper 1, thereby moving the tire bead 2 to a placement position, in which the tire bead 2 can be placed.

[0056] It is noted that due to the conical tip 30 of the separating finger 25 relative to the position of the tire bead 2 engaged by the engagement finger 13, the tire bead 2 can be separated, for example, from an unshown tire bead 2 directly adjacent to the tire bead 2.

[0057] In the steps indicated in Figure 3A and Figure 3B the brake 18 is in its idle position.

[0058] When the gripper 1 is almost in or in the placement position, the brake 18 is moved to its braking position, such that the brake 18 is in braking contact with the gripper frame 10, as indicated schematically in Figure 3C Subsequently, the separating finger 25 is moved towards its radially inward position. Due to the braking contact of the brake 18 with the gripper frame 10, the engagement finger 13 is prevented from moving into its radially inward position, thereby remaining in its radially outward position. The movement of the separating finger 25 towards the radially inward position is limited by the length of the receiving slit 17. When the separating finger 25 is moved radially inward, the conical tip 30 of the separating finger 25 no longer extends radially beyond the engagement face 16 of the engagement finger 13 and the spring 31 between the engagement finger 13 and the separating finger 25 is tensioned.

[0059] As a next step, the ejector fingers 35 are each rotated by means of the rotary piston 39 about their rotation axis A into an ejecting position, as shown in Figure 3D When in the ejecting position, the conical tip 30 of the separating finger 25 is located radially inward of the engagement face 16 of the engagement finger 13, as shown in Figure 3DAs shown, the ejector finger 35 abuts the tire bead 2 engaged by the engagement finger 13, thereby applying an ejecting force to the tire bead 2. Note that the ejecting force is insufficient to push the tire bead 2 away from the engagement finger 13.

[0060] When the ejector finger 35 abuts the tire bead 2, by moving the brake 18 from the braking position to the idle position, the engagement finger 13 is moved radially inwards, preferably at a second speed higher than the first speed, thereby releasing the braking contact between the engagement finger 13 and the gripper frame 10. Due to the tension spring 31 between the engagement finger 13 and the separation finger 25, the engagement finger 13 is pulled rapidly by the spring 31 towards the separation finger 25, thereby releasing the tire bead 2 from the engagement jaw 12. When the engagement finger 13 is pulled rapidly towards the separation finger 25, the ejector finger 35 pushes the tire bead 2 away from the gripper frame 10 to eject the tire bead 2. Optionally, the ejector finger 35 is further rotated slightly towards the conical tip 30 of the separation finger 25, thereby moving into the ejected position.

[0061] Subsequently, the gripper 1, in particular its ejector finger 35, can be moved back into the picking position, as Figure 3A schematically indicated in

[0062] 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 application. From the above discussion, many variations will be apparent to those skilled in the art that remain within the scope of the present application.

[0063] List of reference signs:

[0064] 1 gripper;

[0065] 2 tire bead;

[0066] 10 gripper frame;

[0067] 11 gripper connector;

[0068] 12 engagement jaw;

[0069] 13 engagement finger;

[0070] 14 first connector;

[0071] 15 engagement body;

[0072] 16 engagement face;

[0073] 17 receiving slit;

[0074] 18 brake;

[0075] 25 separation finger;

[0076] 26 second connector;

[0077] 27 connection;

[0078] 28 connecting pin;

[0079] 29 separation;

[0080] 30 conical tip;

[0081] 31 spring;

[0082] 35 ejection finger;

[0083] 36 ejection body;

[0084] 37 first end;

[0085] 38 second end;

[0086] 39 rotating piston;

[0087] 50 bead transfer device;

[0088] 51 robot;

[0089] 52 robot base;

[0090] 53 factory floor;

[0091] 54 robot arm;

[0092] A axis of rotation;

[0093] B braking direction;

[0094] C central axis;

[0095] E ejection direction;

[0096] M movement direction.

Claims

1. A gripper for gripping a tire bead to be transferred from a pick-up position to a drop-off position, the gripper comprising: two or more engagement claws arranged on the gripper at equal angular distances in a circumferential direction, wherein each of the two or more engagement claws is provided with an engagement finger for engaging a tire bead to be gripped, wherein the engagement claws are configured to be moved radially in a movement direction between a remote position, in which the engagement fingers are distanced from the tire bead to be gripped, and an engagement position, in which the engagement fingers engage the tire bead to be gripped, wherein each of the two or more engagement claws is provided with an ejection finger configured for ejecting a tire bead gripped by the gripper from the gripper in an ejection direction transverse to the movement direction by applying an ejection force onto the tire bead.

2. The gripper of claim 1, wherein, The ejection direction is directed away from the gripper.

3. The gripper of claim 1, wherein, The ejection finger is configured to be moved between an idle position, in which the ejection finger is spaced apart from the tire bead, an ejection position, in which the ejection finger abuts against the tire bead, thereby applying the ejection force onto the tire bead, and an ejected position, in which the ejection finger is at least partially positioned at a position past the tire bead.

4. The gripper of claim 3, wherein, The ejection finger is configured to be moved into the ejection position when the associated engagement finger is in the engagement position.

5. The gripper of claim 3, wherein, The ejection finger is configured to be moved into the ejection position when a movement of the associated engagement finger from the engagement position into the remote position is initiated.

6. The gripper of claim 1, wherein, The engagement finger is configured to be moved from the remote position into the engagement position at a first speed and from the engagement position into the remote position at a second speed, wherein the second speed is higher than the first speed.

7. The gripper of claim 1, wherein, Each engagement claw comprises a separation finger configured for separating the tire bead to be gripped from a surface on which the tire bead is located and for being moved between the remote position and the engagement position.

8. The gripper of claim 7, wherein, Each separation finger is provided with a tapered tip arranged in such a way that the tapered tip extends radially beyond the associated engagement finger when the separation finger and the associated engagement finger are in the engagement position.

9. The gripper of claim 7, wherein, The engagement finger and the separation finger of each engagement claw are operatively connected to each other such that a movement of the separation finger from the remote position into the engagement position causes a movement of the engagement finger from the remote position into the engagement position and such that the separation finger can be moved away from the engagement position towards the remote position independently of the engagement finger.

10. The gripper according to claim 1, comprising a driver configured for moving one or more of the engagement claws between the remote position and the engagement position.

11. The gripper of claim 9, comprising a driver configured for moving one or more of the engagement jaws between the remote position and the engagement position, wherein, The driver is operatively connected to the respective separation finger of one or more of the engagement claws.

12. The gripper of claim 11, wherein, The engagement finger of each engagement claw comprises a brake movable between an idle position, in which the engagement finger is enabled to move between the remote position and the engagement position, and a braking position, in which the engagement finger is prevented from moving between the remote position and the engagement position.

13. The gripper of claim 12, wherein, A spring is operatively connected to the engagement finger and the separation finger of each engagement claw and is arranged between the engagement finger and the separation finger.

14. The gripper of claim 7, wherein, The ejection finger of each engagement claw is arranged at the separation finger such that the ejection finger extends in a direction parallel to the movement direction.

15. The gripper of claim 14, wherein, The ejection finger is arranged at the separation finger, which is rotatable about a rotation axis transverse to the movement direction.

16. A method for gripping, by means of a gripper according to claim 1, a tyre bead to be transferred from a pick-up position to a deposit position, wherein, The method comprises the steps of: - moving the gripper towards the pick-up position when the engagement finger is in the remote position; - moving the engagement finger radially into the engagement position, thereby engaging the tyre bead; - moving the gripper towards the deposit position; and - releasing the gripped tyre bead by moving the engagement finger towards the remote position, wherein the method further comprises the step of ejecting the tyre bead from the gripper by means of the ejection finger by exerting an ejection force onto the tyre bead.

17. The method of claim 16, wherein, The ejection finger is configured to move between an idle position, in which the ejection finger is spaced apart from the tyre bead, an ejection position, in which the ejection finger abuts against the tyre bead, thereby exerting the ejection force onto the tyre bead, and an ejected position, in which the ejection finger is at least partially positioned at a position where the tyre bead was located, wherein the step of ejecting the tyre bead comprises moving the ejection finger from the idle position into the ejection position and allowing the ejection finger to move into the ejected position.

18. The method of claim 17, wherein, The step of moving the ejection finger from the idle position into the ejection position is performed before the step of releasing the gripped tyre bead.

19. The method of claim 18, wherein, The step of moving the ejection finger from the idle position into the ejection position is performed simultaneously with the step of releasing the gripped tyre bead.

20. The method of claim 16, when the gripper is the gripper of claim 12, wherein, The step of moving the engagement finger into the engagement position comprises, for each engagement claw, moving the separation finger into the engagement position, thereby moving the associated engagement finger into the engagement position, and moving the brake into the braking position when the separation finger and the associated engagement finger are in the engagement position.

21. The method of claim 20, further comprising: For each engagement claw, the separation finger is moved out of the engagement position towards the remote position when the brake of the associated engagement finger is moved into the braking position.

22. The method of claim 20, wherein, The gripper is according to claim 13, wherein the step of releasing the gripped tyre bead by moving the engagement finger towards the remote position comprises moving the brake into the idle position.

23. A bead transfer device for transferring a tire bead from a pick-up position to a drop-off position, the bead transfer device comprising: a robotic arm and the gripper of claim 1, the gripper being arranged at the robotic arm such that the robotic arm can move the gripper.

24. A computer readable medium having computer executable instructions adapted to cause the gripper of claim 1 to perform the method of claim 16.

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