Technical Field and Prior Art

[0001 ] The invention relates to a thread separation mechanism for a weft feeder device with a winding drum having a winding circumference for storing weft thread. The invention further relates to a weft feeder device comprising a thread separation mechanism.

[0002] In weaving machines, in particular in airjet weaving machines, it is known to provide weft feeder devices with a winding drum for storing a weft thread for a subsequent insertion into a shed. Such weft feeder devices are also referred to as prewinders. The weft thread is stored in several windings on the winding drum. In order to allow for a reliable withdrawal of the stored weft thread, the windings are arranged on the winding drum by means of a thread separation mechanism adjacent to one another or separated from one another in the axial direction of the winding drum.

[0003] EP 0 538 316 B1 shows a thread storage apparatus with a winding drum having an axial direction and a winding circumference formed by a plurality of rod-shaped bearing elements, and a thread separation mechanism. A weft thread is stored in several windings on the winding drum. The thread separation mechanism comprises several rod-shaped advancing elements distributed over the winding circumference, which are moved by means of a drive system relative to the winding drum along a trajectory having radial and axial components for advancing windings of the weft thread in the axial direction along the winding drum. In one embodiment, each thread separation element comprises a bottom part and a top part, which are moveable relative to each other in the axial direction, wherein the drive system comprises two tubular elements formed integrally with the bottom part and the top part, respectively, wherein the tubular elements are actuated to move to-and-fro in the axial direction with a phase shift between the to-and-fro movement of the tubular elements.

Summary of the Invention

[0004] It is an object of the invention to provide a thread separation mechanism allowing for a reliable storing of a weft thread in several windings on a winding drum with a defined distance between the windings. It is a further object of the invention to provide a weft feeder device comprising such a thread separation mechanism. [0005] According to a first aspect of the invention, a thread separation mechanism according to claim 1 is provided. In an embodiment, a thread separation mechanism for a weft feeder device with a winding drum having an axial direction and a winding circumference for storing a weft thread is provided, the thread separation mechanism comprising a separation element arranged at the winding circumference and extending in the axial direction of the winding drum, and a drive system for moving the separation element relative to the winding drum along a trajectory having radial and axial components for advancing windings of the weft thread in the axial direction along the winding drum, wherein the drive system comprises a first carrier element and a second carrier element, wherein the first carrier element and the second carrier element are actuated to move to-and-fro in the axial direction with a phase shift between the to-and-fro movement of the first carrier element and the second carrier element, and wherein the separation element is coupled to the first carrier element and the second carrier element via a linkage system in such manner that the relative movement between the first carrier element and the second carrier element in the axial direction causes a radial movement of the separation element and a conjoint movement of the first carrier element and the second carrier element in the axial direction causes an axial movement of the separation element.

[0006] In order to advance the windings, the separation element is moved along an oval trajectory in a radial direction away from a central axis of the winding drum to protrude from the winding circumference and to come into contact with the windings on the winding drum. Next, the separation element together with the windings is moved in the axial direction of the winding drum towards a withdrawal side for thread to transport the windings towards the withdrawal side. Then, the separation element is moved in the radial direction towards the central axis of the winding drum to place the windings on the winding drum and to lose contact with the windings. Finally, the separation element is moved in the axial direction away from the withdrawal side. The separation distance between two windings depends on the length of the movement in the axial direction. Preferably, the weft feeder device comprises several thread separation mechanisms to move windings arranged in the form of a helix having a defined separation distance along a winding drum.

[0007] According to the invention, the separation element is driven by means of two carrier elements moving to-and-fro in the axial direction with a phase shift between the two movements. As a relative movement between the first carrier elements in the axial direction causes a radial movement of the separation element and a conjoint movement of the carrier elements in the axial direction causes an axial movement of the separation element, the phase shift defines the separation distance between two windings. Hence, in one embodiment, by selecting the phase shift, the separation distance is adjusted. This is possible while all other parameters are kept constant. The phase shift and, hence, the separation distance is selected appropriately by the person skilled in the art. The phase shift in one embodiment is set in manufacturing the thread separation mechanism and/or the weft feeder device. In other embodiments, the phase shift can be adjusted by an operator of the weft feeder device. In addition or in alternative to setting the phase shift, in other embodiments, the separation distance is changed by other measures. For example, in one embodiment, the angle of the inclined hubs, and/or the length of the tilting pins, is changed, resulting in a change of the movement of the carrier elements. In other embodiments, the length of the levers, and/or the position of the guide rods, is changed, resulting in a change of the relative position of the fingers and the separation element. Such measures will have an effect on the trajectory of the separation element with respect to the associated finger and, hence, on the separation distance of the windings.

[0008] In contrast to prior art systems, wherein one tubular element is driven to cause an axial movement, whereas the other tubular element causes the radial movement, in the thread separation mechanism according to the invention both carrier elements contribute to the axial movement as well as to the radial movement.

[0009] According to one embodiment, the drive system comprises a first lever and a second lever. The first lever is pivotally coupled to the first carrier element via a first carrier element joint and pivotally coupled to the separation element via a first separation element joint. The second lever in one embodiment is pivotally coupled to the second carrier element via a second carrier element joint and pivotally coupled to the first lever via a second separation element joint. In preferred embodiments, the second lever is pivotally coupled to the second carrier element via a second carrier element joint and pivotally coupled to the separation element via a second separation element joint.

[0010] In one embodiment, a guiding element is provided for guiding the separation element and to prevent the separation element from tilting with respect to the central axis. In preferred embodiments, the drive system comprises a pair of first levers pivotally coupled to the first carrier element via first carrier element joints and pivotally coupled to the separation element via first separation element joints, wherein the first levers of the pair of first levers are of equal length and are arranged in parallel. Thereby, a simple structure is achieved.

[001 1 ] Preferably, the second lever is arranged between the two levers of the pair of first levers. This allows for a very compact structure. [0012] In preferred embodiments, the at least one first lever, or if applicable the first levers of the pair of first levers, and the second lever have equal length.

[0013] In one embodiment, the first carrier element and/or the second carrier element move along an arched path mainly in the axial direction of the winding drum. For a simple structure, in preferred embodiments, the first carrier element and the second carrier element move in parallel to the axial direction of the winding drum. This also allows to obtain a constant separation distance between the windings. In alternative, the carrier elements do not move in parallel but at a small angle with respect to the axial direction and/or with respect to the fingers of the winding drum, which allows to change the separation distance between the windings in axial direction along the winding drum.

[0014] In preferred embodiments, the first carrier element and/or the second carrier element are designed as a carriage moving along at least one guiding rod. The guiding rod locks four out of six degrees of freedom of the carriage. Preferably, a pair of guiding rods, more preferably a pair of guiding rods comprising two linear guiding rods extending in parallel to the axial direction of the winding drum, is provided for further preventing a rotation of the carriage about an axis of the guiding rod. Hence, by means of the pair of guiding rods, five out of six degrees of freedom of the carriage are locked and the movement of the carriage is restricted to a movement in the axial direction. In one embodiment, both carriages are arranged slidingly on the shared pair of guiding rods. In other embodiments the two carriages are arranged on separate guiding rods or separate pairs of guiding rods, wherein one carriage is slidingly arranged on an arced guiding rod or an arced pair of guiding rods. In preferred embodiments, the sliding connection comprises bearings in order to minimize any friction.

[0015] The thread separation mechanism, more particular the drive system, further comprises a structure and/or elements for moving the carrier elements to-and-fro. In preferred embodiments, the first carrier element is driven to move to-and-fro by means of a first tilting pin and the second carrier element is driven to move to-and-fro by means of a second tilting pin. In preferred embodiments, the first tilting pin is assigned to a first inclined rotating hub and the second tilting pin is assigned to a second inclined rotating hub. The inclined rotating hubs in preferred embodiments are mounted on a central driving shaft to rotate together with the central driving shaft. The inclined rotating hubs in one embodiment are manufactured and mounted separately. In other embodiments, the inclined rotating hubs are integrally manufactured as cams of one single shaft-like element. The inclined rotating hubs in one embodiment are arranged eccentric with respect to the central axis of the driving shaft as described in EP 0 538 316 B1 , the content of which is herewith incorporated by reference. The tilting pins are each mounted on a sleeve, which sleeves are mounted rotatably on the two hubs, respectively, wherein due to the rotation of the inclined rotating hubs, a wobbling movement is imposed to the sleeves and, hence, the tilting pins are tilted forward and backward. With each revolution of the central driving shaft, the tilting pins perform a pivot movement cycle between a first extreme position, in which the tilting pins are tilted towards the withdrawal side, and a second extreme position, in which the tilting pins are tilted away from the withdrawal side, with a phase shift between the pivot movement of the first tilting pin and the pivot movement of the second tilting pin. In one embodiment, a phase shift between the two inclined rotating hubs in circumferential direction can be adjusted for adjusting the phase shift between the to-and-fro movement of the first carrier element and the second carrier element.

[0016] Preferably, the carrier elements are designed as carriages as described above, wherein a movement of the carriages caused by the tilting pins is restricted to a movement of the carriages along the at least one guiding rod, in particular is restricted to a movement of the carriages in axial direction along a pair of parallel guiding rods extending in the axial direction of the winding drum. In order to couple the carriages or any alternative carrier elements to the tilting pins, in preferred embodiments a first cylinder is fixedly mounted to the first carrier element, wherein a distal end of the first tilting pin is mounted in the first cylinder and/or a second cylinder is fixedly mounted to the second carrier element, wherein a distal end of the second tilting pin is mounted in the second cylinder. The cylinder and the tilting pins extend at least essentially in the radial direction. The tilting pin in preferred embodiments is received in the associated cylinder moveable in the longitudinal direction. Hence, a displacement of the tilting pin in the radial direction is not transmitted to the carrier elements. In addition, the carrier elements in one embodiment are moveable in the radial direction for an adjustment of the winding circumference. As the tilting pins are received in the associated cylinders moveable in the radial direction, the adjustment of the winding circumference is possible without the necessity to dismount the thread separation mechanism.

[0017] In order to avoid a transmission of the tilting movement to an associated cylinder, in one embodiment the tilting pins and/or the cylinders are elastically deformable. In preferred embodiments, the distal end of each of the tilting pins is mounted in the associated cylinder by means of a ball system.

[0018] In one embodiment, the separation element contacts the windings of the weft thread with a contact area extending in the axial direction of the winding drum. In preferred embodiments, the separation element comprises a plurality of contact rails for contacting the windings of the weft thread. The contact rails are also referred to as contact bars, contact tracks or contact tongues. In preferred embodiments, the contact rails are formed integrally with the rigid separation element. In other embodiments, the contact rails are manufactured separately from a different material and fixedly coupled to the main body of the separation element. The contact rails perform a conjoint movement in the radial direction for making contact with the windings of the weft thread, in the axial direction for advancing the windings, in the radial direction away from the windings and in the axial direction away from the withdrawal side. The contact rails are distributedly arranged over the winding circumference. In preferred embodiments, four contact rails are provided at each separation element.

[0019] According to a second aspect a weft feeder device with a winding drum having a winding circumference for storing a weft thread is provided, wherein the weft feeder device comprises a thread separation mechanism as described above.

[0020] In preferred embodiments, the winding drum comprises a plurality of fingers which are distributed over the winding circumference of the winding drum, wherein a separation element is assigned to each of the fingers. In preferred embodiments, four fingers positioned at intervals of 90° are provided.

[0021 ] Each separation element assigned to one of the plurality of fingers comprises two carrier elements, preferably two carriages, which are moved to-and-fro with a phase shift between the to-and-fro movement of the first carrier element and the second carrier element. In preferred embodiments, the carrier elements are driven by means of associated tilting pins, wherein all tilting pins driving the first carrier elements of the plurality of separation elements are mounted on a first shared sleeve, so as to extend in radial direction, and all tilting pins driving the second carrier elements of the separation elements are mounted on a second shared sleeve, so as to extend in radial direction. The first shared sleeve and the second shared sleeve are assigned to a first inclined rotating hub and a second inclined rotating hub, respectively, which impose a wobbling movement to the sleeves.

[0022] In preferred embodiments, each finger comprises a plurality of spaced contact portions, wherein the associated separation element is provided with a plurality of contact rails, each contact rail is arranged between two contact portions of the finger, and driven to temporarily protrude between the contact portions for advancing the windings of the weft thread.

[0023] In one embodiment, the winding circumference of the weft feeder device is fixed. In preferred embodiments, at least one of the plurality of fingers is moveable in the radial direction of the winding drum in order to change the length of the winding circumference. The carrier elements, in particular the carriages in preferred embodiments are moved in radial direction together with the finger. In one embodiment, the guiding rails are mounted on the finger, so that when moving the finger the guiding rails are displaced together with the finger. In preferred embodiments, the tilting pins and the cylinders provided on the carriages are designed to compensate the displacement of the carriages in the radial directions.

Brief Description of the Drawings

[0024] Further characteristics and advantages of the invention will emerge from the following description of the embodiments schematically illustrated in the drawings. Throughout the drawings, the same elements will be denoted by the same reference numerals. In the drawings:

[0025] Figure 1 is a schematic illustration of a thread separation mechanism in a first phase,

[0026] Figure 2 is a schematic illustration of the thread separation mechanism of figure 1 in a second phase,

[0027] Figure 3 is a schematic perspective view of a drive system of the thread separation mechanism of figures 1 and 2;

[0028] Figure 4 is a schematic perspective view of the drive system of figure 3, wherein a second carriage is removed;

[0029] Figure 5 is a schematic perspective view of the drive system of figure 3, wherein a first carriage is removed;

[0030] Figure 6 is a schematic sectional view of a part of the drive system of figure 5;

[0031 ] Figure 7 is a perspective view of a thread separation mechanism comprising the drive system of figure 3;

[0032] Figure 8 is a perspective view of the thread separation mechanism of figure 7 together with the finger and a central driving shaft;

[0033] Figure 9 is a partial cross section of the thread separation mechanism of figure 8; and [0034] Figure 10 is a front view of a weft feeder device. Detailed Description of Embodiments

[0035] Figures 1 and 2 schematically show a thread separation mechanism 1 for a weft feeder device 30 (shown in figure 10), which weft feeder device 30 has a winding drum 31 , a central driving shaft 29 and a winding circumference for storing weft thread. The winding circumference is formed by a plurality of fingers 2 schematically illustrated as a line in figure 1 and that determine the winding drum 31. The winding drum 31 extends in axial direction A indicated by an arrow in figure 1 .

[0036] The thread separation mechanism 1 comprises a separation element 3 arranged at the winding circumference, in particular disposed near the fingers determining the winding circumference, and extending in the axial direction A of the winding drum. The separation element 3 is moved along a trajectory 4 having radial and axial components for advancing windings 32 (shown in figure 1 and 2) of the weft thread in the axial direction A along the fingers 2 of the winding drum.

[0037] More particular, as generally known in order to advance the windings 32, the separation element 3 is moved along an oval trajectory 4 in a radial direction R indicated by an arrow in figure 1 away from a central driving shaft 29 of the winding drum 31 (upwards in figure 1 ) to protrude from the winding circumference defined by the fingers 2 as shown in figure 1 . At the phase of the movement shown in figure 1 , the separation element 3 comes into contact with the windings 32 (schematically shown in figure 1 ). After the separation element 3 protrudes from the winding circumference, the separation element 3 is moved in the axial direction A of the winding drum towards a thread withdrawal side to transport the winding towards the withdrawal side (to the right in figure 1 ). Next, the separation element 3 is moved in the radial direction R towards the central axis of the winding drum (downwards in figure 2) to place the winding on the finger 2 and to lose contact with the winding. Finally, the separation element 3 is moved back to the starting position in the axial direction A away from the withdrawal side (to the left in figure 2).

[0038] In order to move the separation element 3 along the trajectory 4 relative to the winding drum, the thread separation mechanism 1 further comprises a drive system 5.

[0039] The drive system 5 comprises a first carrier element 6 and a second carrier element 7, wherein the first carrier element 6 and the second carrier element 7 are actuated to move along a path B to-and-fro in the axial direction A with a phase shift between the to-and-fro movement of the first carrier element 6 and the second carrier element 7. The separation element 3 is coupled to both carrier elements 6, 7. More particular, the separation element 3 is coupled to the first carrier element 6 and the second carrier element 7 via a linkage system 8 in such manner that the relative movement (as schematically shown in figure 2) between the first carrier element 6 and the second carrier element 7 in the axial direction A causes a radial movement of the separation element 3 and that a conjoint movement (as schematically shown in figure 1 ) of the first carrier element 6 and the second carrier element 7 in the axial direction A causes an axial movement of the separation element 3.

[0040] In the schematic illustration shown in figures 1 and 2, the linkage system 8 comprises a pair of first levers 9, 10 and a second lever 1 1 . The first levers 9, 10 of the pair of first levers are of equal length and are arranged in parallel. In alternative, it is possible to design a separation mechanism having first levers that are not of equal length and/or that are not in parallel. Although too large differences will give detrimental results, small differences can be handled and can be used to change the behavior of the separation element. Preferably, the first levers 9, 10 and the second lever 1 1 have equal length. In alternative, it is possible to design a separation mechanism having first levers and a second lever of different length, wherein a length difference between the first levers and the second lever will have an effect on the trajectory of the separation element, for example will result in a more asymmetrical trajectory.

[0041 ] Both first levers 9, 10 are pivotally coupled to the first carrier element 6 via a first carrier element joint 12 and pivotally coupled to the separation element 3 via a first separation element joint 13. The two first levers 9, 10, the first carrier element 6 and the separation element 3 together form a parallelogram, wherein the separation element 3 is always in parallel to the axial direction A. In other embodiments, only one first lever 9 is provided, wherein the orientation of the separation element 3 is achieved by alternative means, for example a guiding surface.

[0042] The linkage system 8 shown in figures 1 and 2 further comprises a second lever 1 1 , which is pivotally coupled to the second carrier element 7 via a second carrier element joint 14 and, which is also pivotally coupled to the separation element 3 via a second separation element joint 15. In other embodiments, the second lever 1 1 is not directly coupled to the separation element 3, but to one of the first levers 9, 10.

[0043] In the embodiment shown, the two carrier elements 6, 7 are moved along a linear path B in the axial direction. In other embodiments, the second carrier element 7 is moved along an arched path.

[0044] Further, in the embodiment shown, the second lever 1 1 is arranged between the two levers 9, 10 of the pair of first levers. Arranging the second lever 1 1 between the first levers 9, 10 is preferred, as it allows a compact design and also allows a long distance between the first levers 9, 10, which is advantageous to limit errors in the orientation of the separation element due to tolerances. In other embodiments, the second lever 1 1 is arranged adjacent to the pair of first levers.

[0045] In order to allow for a simple structure, in the embodiment shown the second lever 1 1 has the same length as the first levers 9, 10 and the first carrier element joints 12 and the second carrier element joint 14 are moved along the same plane.

[0046] Figure 3 schematically shows an embodiment of the drive system 5 and the linkage system 8 in a perspective view. In the embodiment shown, the first carrier element 6 and the second carrier element 7 each are designed as a carriage moving along a shared pair of guiding rods 16. The carriage functioning as the first carrier element 6 is referred to as first carriage. The carriage functioning as the second carrier element 7 is referred to as second carriage. Figure 4 shows the drive system 5 of Figure 3, wherein the second carrier element 7 is removed. Figure 5 shows the drive system 5 of Figure 3, wherein the first carrier element 6 is removed.

[0047] In the embodiment shown, both carrier elements 6, 7 are slidingly coupled to one shared pair of guiding rods 16. Thereby, the number of elements is minimized. In other embodiments, two distinct pairs of guiding rods or three guiding rods for forming two pairs having one shared guiding rod are provided.

[0048] The drive system 5 further comprises a first tilting pin 17 and a second tilting pin 18. As will be explained in more detail below, the tilting pins 17, 18 are moved between a first position, in which the tilting pin 17, 18 is tilted forward and second position, in which the tilting pin 17, 18 is tilted backward. The first carrier element 6 is driven to move to-and-fro by means of the first tilting pin 17, wherein the guiding rods 16 restrict the movement of the first carrier element 6 so that the first carrier element 6 moves in parallel to the axial direction A. In other words, the tilting movement is not transmitted to the first carrier element 6. The second carrier element 7 is driven to move to-and-fro by means of the second tilting pin 18, wherein the guiding rods 16 restrict the movement of the second carrier element 7 so that the second carrier element 7 also moves in parallel to the axial direction A.

[0049] The first tilting pin 17 is arranged on a first sleeve 19, wherein the tilting pin 17 extends at least essentially in radial direction of the first sleeve 19. The second tilting pin 18 is arranged on a second sleeve 20, wherein the tilting pin 18 extends at least essentially in radial direction of the second sleeve 20. The first sleeve 19 rotatably receives a first inclined rotating hub 21 and the second sleeve 20 rotatably receives a second inclined rotating hub 22, wherein the inclined rotating hubs 21 , 22 are only partly visible in figures 3 to 5. The inclined rotating hubs 21 , 22 are arranged on a central driving shaft 29 (shown in figure 8) to rotate with the central driving shaft 29. Due to the rotation of the inclined rotating hubs 21 , 22, a wobbling movement is imposed to the sleeves 19, 20, causing a tilting movement of the tilting pins 17, 18. Preferably, a plurality of tilting pins, more particular four tilting pins positioned at intervals of 90°, are mounted to each sleeve 19, 20, wherein each tilting pin drives a first carrier element 6 or a second carrier element 7 of an associated thread separation mechanism 1 . Each tilting pin 17, 18 is hereby arranged in an assigned opening 35, 36 of a sleeve 19, 20, wherein in the embodiment shown the openings 35, 36 are positioned at intervals of 90°. In the embodiment shown, the two hubs 21 , 22 are formed by a common element. In other embodiments two elements are provided, each associated to a hub.

[0050] For coupling the first carrier element 6 and the first tilting pin 17, a first cylinder 23 is fixedly mounted to the first carrier element 6, wherein a distal end of the first tilting pin 17 is slidingly received in the first cylinder 23. Similar, for coupling the second carrier element 7 and the second tilting pin 18, a second cylinder 24 is fixedly mounted to the second carrier element 7, wherein a distal end of the second tilting pin 18 is slidingly received in the second cylinder 24.

[0051 ] Figure 6 is a schematic sectional view of a part of the drive system 5 of figure 5. As can be seen in figure 6, the distal ends of the tilting pins 17, 18 are each mounted in the associated cylinders 23, 24 by means of a ball system 25, 26. The ball systems 25, 26 are received in the associated cylinders 23, 24, wherein only the movement of the tilting pins 17, 18 in the axial direction A of the winding drum is transmitted to the cylinders 23, 24, whereas neither a pivot component nor the radial component of the movement of the tilting pins 17, 18 are transmitted to the cylinders 23, 24 and, hence, to the carrier elements 6, 7.

[0052] Figure 7 is a perspective view of the thread separation mechanism 1 comprising the separation element 3, the drive system 5 of figures 3 to 6, and the linkage system 8, wherein the separation element 3 is coupled to the drive system 5 by means of the linkage system 8. The separation element 3 comprises a plurality of contact rails 27 with which the separation element 3 contacts the windings in several distinct areas. In the embodiment shown, four contact rails 27 are provided. The contact rails 27 are formed integrally via connecting elements 33 and, hence, perform a conjoint movement along a defined trajectory for advancing a winding. [0053] Figure 8 is a perspective view of the thread separation mechanism 1 of figure 7 together with a finger 2 and a central driving shaft 29. The central driving shaft 29 extends in axial direction.

[0054] As can be best seen in figure 8, the finger 2 comprises a plurality of spaced contact portions 28. Each of the contact rails 27 is arranged between two contact portions 28 of the finger 2. By means of the drive system 5, the separation element 3 with the contact rails 27 is driven in such manner that the contact rails 27 temporarily protrude between the contact portions of the finger 2 in order to advance the windings of the weft thread. Each separation element 3 is driven by two carrier elements 6, 7 (shown in figure 9) for moving the separation element 3, and two tilting pins 17, 18 for driving the carrier elements 6, 7.

[0055] As will be clear by the person skilled in the art, a complete weft feeder device 30 (shown in figure 10) with the elements of figure 9 has a winding drum 31 formed by a plurality of, namely four fingers 2, which are evenly distributed about a central axis to form a winding circumference. A separation element 3 is assigned to each of the fingers 2.

[0056] The first tilting pins 17 of all thread separation mechanisms 1 are mounted on a first sleeve 19. A wobbling movement is imposed to the first sleeve 19, wherein the tilting pins 17 mounted on the first sleeve 19 are consecutively tilted forward and backward. In the same way, the second tilting pins 18 of all thread separation mechanisms 1 are mounted on a second sleeve 20 and a wobbling movement is imposed to the second sleeve 20, so that the tilting pins 18 mounted on the second sleeve 20 are consecutively tilted forward and backward. The tilting pins 17, 18 drive the carrier elements 6, 7 for moving each separation element 3 along an oval trajectory in order to advance the windings of a weft thread stored on the winding drum.

[0057] As shown in figure 10, the winding drum 31 comprises a plurality of fingers 2 which are distributed over the winding circumference of the winding drum 31 , wherein a separation element 3 is assigned to each of the fingers 2. At least one of the plurality of fingers 2 is displaceable in the radial direction of the winding drum 31 in order to change the length of the winding circumference. In an embodiment, three fingers 2 are displaceable in the radial direction, while one finger can be set in a fixed radial position, for example the finger that is arranged near the magnet pin 34.

[0058] The thread separation mechanism according to the invention can be used in any type of weaving machine. The thread separation mechanism and the weft feeder device are not limited to the embodiments described by way of example and shown in the drawings, also variants and combinations of the described and shown embodiments are possible that fall under the claims.