TECHNICAL FI ELD AND PRIOR ART

[0001 ] The invention relates to a weft feeder device comprising a winding drum with a drum axis and an adjustable winding circumference for storing weft thread, and a guide structure, wherein the winding drum comprises at least one drum segment, which drum segment is moveable in a radial direction with respect to the drum axis upon adjusting the winding circumference of the winding drum.

[0002] As generally known, a weft feeder device comprises an almost cylindrical winding drum onto which a rotating winding arm winds a plurality of turns or windings of a weft thread. The winding drum comprises several drum segments distributed about the drum axis.

[0003] In the context of the application, "axial direction" is defined as a direction along the drum axis. For adjusting the winding circumference, the drum segments are moveable in a radial direction of the drum axis. A direction perpendicular to the axial direction of the drum axis and perpendicular to the radial direction of the drum axis is referred to as lateral direction. [0004] In the prior art, winding drums are known that comprise a plurality of "resting drum segments", which are arranged to form an almost cylindrical winding drum defining a winding circumference. The "resting drum segments" are only moved in a radial direction with respect to a drum axis upon adjusting the winding circumference, but not moved upon winding or unwinding a weft thread to or from the winding drum. It is further known to provide "feeding drum segments", which are moved in the radial direction with respect to the drum axis upon adjusting the winding circumference and which are moved together with a guide structure upon winding or unwinding a weft thread to or from the winding drum in order to advance at least a singular winding in parallel to the axial direction of the drum axis.

[0005] For example, WO 95/24521 A1 discloses a weft feeder device with a winding drum, which weft feeder device comprising resting drum segments and feeding drum segments. The resting drum segments and the feeding drum segments are each provided with a central rod extending in the radial direction with respect to a drum axis. The central rods are mounted to threaded pins provided at respective guide structures, wherein by turning the threaded pins the drum segments are moveable in the radial direction. [0006] EP 0930386 A1 also shows a weft feeder device, wherein resting drum segments and feeding drum segments of a winding drum are provided with central rods extending in the radial direction with respect to a drum axis, which central rods are guided in a respective guide structure. In accordance with EP 0930386 A1 further two cam disks are provided. Each central rod is provided with engaging pins that are engaged with spiral grooves formed on the cam disks, wherein by rotating the cam disks the drum segments are moveable in the radial direction.

[0007] WO 2015/16961 1 A1 shows an adjustably arranged drum segment having two side legs, wherein a first side leg is a guiding leg and a second side leg is provided with a rack cooperating with a pinion for adjusting the winding circumference.

[0008] Upon operation, the resting drum segments generally have to be held fixed in position with respect to the guide structure to maintain a set winding circumference. It is known, amongst others from WO 95/24521 A1 and EP 0930386 A1 , to provide a wobbling or moving guide structure for the feeding drum segments, which guide structure is moved so that the feeding drum segments are moving in a pattern for advancing the windings on the winding drum. Generally, such a wobbling movement is obtained by using an eccentric and an inclined hub. When providing a wobbling guide structure, the central rods of the feeding drum segments during the wobbling movement still need to be fixed in position with respect to the guide structure and/or a movement mechanism for moving the feeding drum segments with respect to the guide structure in order to avoid excessive wear of the central rods, the guide structure and/or the movement mechanism and the housing.

SUMMARY OF THE I NVENTION

[0009] It is the object of the invention, to provide a weft feeder device comprising a winding drum with an adjustable winding circumference allowing for a reliable positioning of a drum segment in a guide structure.

[0010] This object is solved by the weft feeder device with the features of claim 1 . Advantageous embodiments are defined in the dependent claims.

[001 1 ] According to a first aspect, a weft feeder device comprising a winding drum with a drum axis and with an adjustable winding circumference for storing weft thread , and a guide structure with a bearing seat is provided, wherein the winding drum comprises at least one drum segment mounted to the guide structure so as to be moveable in a radial direction with respect to the drum axis, wherein the drum segment comprises at least one guiding leg which guiding leg is moveably in its longitudinal direction mounted in the bearing seat of the guide structure, and wherein the bearing seat comprises at least one resiliently mounted pressing element, which is acting on the guiding leg for reducing play between the guiding leg and the associated bearing seat.

[0012] In the context of the application, a resiliently mounted pressing element, shall be understood as meaning that the pressing element is mounted using a resiliently deformable material and/or a resiliently deformable element, wherein the pressing element is forced against the guiding leg by means of a restoring force of the resiliently deformable material and/or the resiliently deformable element and wherein the pressing element is moveable away from the guiding leg against the restoring force of the resiliently deformable material and/or the resiliently deformable element.

[0013] The weft feeder device in one embodiment is provided with a central rod, which cooperates with a drive mechanism for adjusting a winding circumference. In one embodiment, at least one guiding leg is provided which is arranged in parallel but at a distance to the central rod. In alternative or in addition, the central rod functions as the guiding leg. In still another embodiment, the drum segment comprises two guiding legs arranged at the lateral ends of the drum segment, wherein one of the guiding legs is used for moving the drum segment with respect to the guide structure for adjusting the winding circumference. In this case, the drum segment is not provided with an additional central rod.

[0014] In one embodiment, the at least one resiliently mounted pressing element comprises a low friction surface for contacting the associated guiding leg. In this case, the resilient mounted pressing element functions as a plain bearing seat.

[0015] In an alternative embodiment, the at least one pressing element is a resiliently mounted rolling element. The axis of the rolling element is arranged perpendicular to the movement direction of the associated guiding leg. In one embodiment, the axis of the rolling element is resiliently mounted in a bracket. In another embodiment, the axis is mounted fixed in position in a bracket, which bracket is resiliently mounted at the guide structure.

[0016] In one embodiment, the bearing seat comprises two resiliently mounted rolling elements arranged at a distance to one another in the longitudinal direction of the guiding leg. In particular, the rolling elements are evenly distributed about the periphery of the guiding leg. [0017] The at least one rolling element, at least one of the two rolling elements or all rolling elements in particular are wheels or rollers. The size and/or shape of the rolling elements are adapted to the shape of the guiding leg. In one embodiment, the at least one resiliently mounted rolling element or at least one of the two resiliently mounted rolling elements is a wheel with a V-shaped or U-shaped groove for contacting the guiding leg. Such a shape is advantageous for guiding legs having a circular cross-section.

[0018] In one embodiment, the bearing seat comprises at least one stationary mounted rolling element, in particular a pair of stationary mounted rolling elements arranged at a distance to one another in the longitudinal direction of the guiding leg, wherein the resiliently mounted pressing element forces the guiding leg against the at least one first stationary mounted rolling element. The stationary mounted rolling element in one embodiment is combined with at least one resiliently mounted rolling element for providing a roller bearing. In an alternative embodiment, the stationary mounted rolling element is combined with at least one resiliently mounted pressing element having a low friction surface for contacting the guiding leg. [0019] In another embodiment, the bearing seat comprises a low friction surface, wherein the resiliently mounted pressing element forces the guiding leg against the low friction surface. By means of the resiliently mounted pressing element, play in the bearing seat is reduced. The low friction surface functions as a plain bearing seat for the guiding leg. The low friction surface at the bearing seat in one embodiment is combined with at least one resiliently mounted pressing element having a low friction surface for contacting the guiding leg, thereby providing a plain bearing seat. In an alternative embodiment, the low friction surface at the bearing seat is combined with at least one resiliently mounted rolling element.

[0020] In one embodiment, a blocking mechanism operative to selectively take a blocking state and a release state is provided, wherein in the blocking state the blocking mechanism blocks a movement of the at least one guiding leg with respect to the guide structure. By means of the blocking mechanism, an undesired movement of the guiding legs and, thus, the associated drum segment, with respect to the guide structure is avoided when the blocking mechanism is in its blocking state. Hence, a movement is not possible or only possible when applying forces higher than forces expected in normal operation. On the other hand, when the blocking mechanism is in its release state a movement of the at least one guiding leg with respect to the guide structure is not blocked, and, thus possible, in particular it is easily possible for adjusting a winding circumference. In advantageous embodiments, the blocking mechanism makes use of the at least one resiliently mounted rolling element, wherein the at least one resiliently mounted rolling element is forced against the associated guiding leg for blocking the associated guiding leg in a bearing seat, and wherein in the release state a contact force between the at least one resiliency mounted rolling element and the associated guiding leg is cancelled or reduced for a movement of the associated guiding leg in the bearing seat. In other embodiments, additional non-rotatable, resiliency mounted pressing elements are provided, which are forced against the guiding legs in the blocking state.

[0021 ] In one embodiment, the at least one drum segment is a resting drum segment. In advantageous embodiments, the at least one drum segment is a feeding drum segment and the guide structure is arranged for moving together with the feeding drum segment for advancing windings of the weft thread. In particular embodiments, the winding drum comprises a plurality of feeding drum segments, each feeding drum segment comprising at least one guiding leg, wherein the guiding legs of the feeding drum segments are guided in one common guide structure. As mentioned above, in one embodiment, a central rod functions as the guiding leg. In other embodiments, each feeding drum segment comprises at least one guiding leg, which is distinct from a central rod. [0022] According to one embodiment, the at least one drum segment comprises a first guiding leg and a second guiding leg each extending in parallel to the movement direction of the drum segment at a lateral distance to one another, wherein the first guiding leg is mounted moveably in a first bearing seat of the guide structure and the second guiding leg is mounted moveably in a second bearing seat of the guide structure. [0023] In one embodiment, the first guiding leg and the second guiding leg of the least one drum segment are arranged at an axial distance to one another in the axial direction of the drum axis. The axial distance is advantageous both for stabilizing the system and for allowing the guiding legs of several drum segments mounted to a common guide structure to be moved over large distances without interference. [0024] In one embodiment, the first bearing seat and the second bearing seat each comprise at least one resiliency mounted pressing element, which is acting on one of the first guiding leg and the second guiding leg, respectively, for reducing play between the associated first guiding leg and the first bearing seat and the associated second guiding leg and the second bearing seat, respectively. In other embodiments, only one of the two guiding legs is provided with a pressing element.

[0025] In one embodiment, at least one of the first guiding leg and the second guiding leg is arranged centrally so as to extend along the movement direction of the drum segment. [0026] In advantageous embodiments, the drum segment comprises a central rod extending in a radial direction with respect to the drum axis, wherein the first guiding leg extends at a first lateral distance to the central rod at a first side of the central rod and the second guiding leg extends at a second lateral distance to the central rod at a second side of the central rod. When providing a central rod, forces acting on the drum segment upon adjusting the position can be applied centrally on the drum segment and undesired torques or moments acting on the drum segment can be avoided when driving the drum segment for adjusting a winding circumference.

[0027] In one embodiment, at least one of the first guiding leg and the second guiding leg is arranged at an axial distance to the central rod in the axial direction of the drum axis. As mentioned above, the axial distance is advantageous both for stabilizing the system and for allowing the guiding legs as well as the central rod of several drum segments mounted to a common guide structure to be moved over large distances without interference.

[0028] For moving the drum segments upon adjusting the winding circumference, a manually-operated or motor driven drive mechanism is provided. In one embodiment, the drive mechanism comprises a cam disk comprising a spiral groove engaging with at least one engagement element provided at the central rod.

[0029] As mentioned above, in case only one guiding leg is provided, the central rod in particular is provided with a guiding portion. However, in case two guiding legs are provided, in one embodiment the central rod is mounted with a clearance space in the guide structure. In this embodiment, the central rod is not used for guiding the drum segment. Thereby, a mechanically overdetermined system is avoided.

[0030] According to a second, alternative or additional aspect, a weft feeder device comprising a winding drum with a drum axis and with an adjustable winding circumference for storing weft thread, and a guide structure with a bearing seat is provided, wherein the winding drum comprises at least one drum segment mounted to the guide structure so as to be moveable in a radial direction with respect to the drum axis, wherein the drum segment comprises at least one guiding leg, which guiding leg is moveably in its longitudinal direction mounted in the bearing seat of the guide structure, and wherein the weft feeder device further comprises a blocking mechanism operative to selectively take a blocking state and a release state, wherein in the blocking state the blocking mechanism blocks a movement of the at least one guiding leg with respect to the guide structure. [0031 ] Such a blocking mechanism is in particular advantageous in case the drum segment is a feeding drum segment, wherein the blocking mechanism can be operated to take the release state upon adjusting the winding circumference and the blocking state upon use of the winding drum, when the guide structure together with the feeding drum segment mounted thereon is driven to perform a wobbling movement for advancing windings of a weft thread.

[0032] The weft feeder device in one embodiment is provided with a central rod, which cooperates with a drive mechanism for adjusting a winding circumference. In one embodiment, at least one guiding leg is provided which is arranged in parallel but at a distance to the central rod. In alternative or in addition, the central rod functions as the guiding leg. In still another embodiment, the drum segment comprises two guiding legs arranged at the lateral ends of the drum segment, wherein one of the guiding legs is used for moving the drum segment with respect to the guide structure for adjusting the winding circumference. In this case, the drum segment is not provided with an additional central rod.

[0033] In one embodiment, the blocking mechanism comprises at least one pressing element moveably mounted in the bearing seat, wherein in the blocking state the at least one pressing element is forced against the guiding leg for forcing the guiding leg against the bearing seat, and wherein in the release state a pressing force applied by the at least one pressing element on the guiding leg is cancelled or reduced for allowing a movement of the guiding leg along the bearing seat. [0034] By means of the pressing element, a movement perpendicular to the longitudinal direction of the guiding leg is avoided. Further, the pressing element functions as a brake acting on the guiding leg for avoiding a movement along the longitudinal direction of the guiding leg.

[0035] In one embodiment, the at least one pressing element is a resiliently mounted pressing element, wherein the pressing element is moveable against a restoring force away from the guiding leg.

[0036] In the context of the application, a resiliently mounted pressing element, shall be understood as meaning that the pressing element is mounted using a resiliently deformable material and/or a resiliently deformable element, wherein the pressing element is forced against the guiding leg by means of a restoring force of the resiliently deformable material and/or the resiliently deformable element and wherein the pressing element is moveable away from the guiding leg against the restoring force of the resiliently deformable material and/or the resiliently deformable element.

[0037] The resilience and/or the size, shape and material of the pressing element are chosen to allow sufficient force acting on the guiding leg to avoid movement, vibration and wear. [0038] In one embodiment, the resiliently mounted pressing element is arranged to apply a restoring force in the blocking state. In this case, in one embodiment in the release state the restoring force acting on the at least one resiliently mounted pressing element is cancelled. In other words, no restoring force or only a negligible restoring force is acting on the at least one resiliently mounted pressing element in the release state. In an alternative embodiment, in the release state the restoring force acting on the at least one resiliently mounted pressing element is reduced. In other words, the restoring force is acting on the at least one resiliently mounted pressing element in the release state. Thereby, a play in the bearing seat in the release state is reduced.

[0039] In one embodiment, the blocking mechanism comprises an actuator device, short also referred to actuator, which in the release state is unpowered to cancel or at least reduce the restoring force acting on the at least one resiliently mounted pressing element. In other words, the actuator forces the blocking mechanism into the blocking state. In advantageous embodiments, the blocking mechanism comprises an actuator, which in the release state is powered to cancel or at least reduce the restoring force acting on the at least one resiliently mounted pressing element. In this case, during operation of the weft feeder device the actuator is unpowered and powering of the actuator is only necessary for adjusting the winding circumference. In one embodiment, the actuator used for powering the blocking mechanism is also used for driving the drive mechanism of the weft feeder device for moving the drum segments upon adjusting the winding circumference. In other embodiments, two distinct actuators are provided.

[0040] The actuator can be chosen suitably by the person skilled in the art. For example, the actuator is selected to be one of an electrical motor, an electromagnet or a wire that changes length with current. In advantageous embodiments, the actuator comprises an electromagnetic coil. [0041 ] In one embodiment, the at least one drum segment is a resting drum segment. In advantageous embodiments, the at least one drum segment is a feeding drum segment and the guide structure is arranged for moving together with the feeding drum segment for advancing windings of weft thread. In particular embodiments, the winding drum comprises a plurality of feeding drum segments, each feeding drum segment comprising at least one guiding leg, wherein the guiding legs of the feeding drum segments are guided in one common guide structure. As mentioned above, in one embodiment, a central rod functions as the guiding leg. In other embodiments, each feeding drum segment comprises at least one guiding leg, which is distinct from a central rod.

[0042] In one embodiment, the weft feeder device comprises a first subgroup and a second subgroup, wherein the second subgroup is moved with respect to the first subgroup for performing a wobbling movement for advancing windings of weft thread. The first subgroup is for example a resting drum arrangement comprising a plurality of resting drum segments, which are guided in a guide structure and are moveable with respect to the guide structure for adjusting the winding circumference, whereas the second subgroup is a feeding drum arrangement comprising a plurality of feeding drum segments, which are guided in a guide structure and are moveable with respect to the guide structure upon adjusting the winding circumference.

[0043] The blocking mechanism is in particular designed to act on guiding legs of the second subgroup performing a wobbling movement. To this end, the blocking mechanism is at least in part arranged at the second subgroup, wherein in particular the actuator of the blocking mechanism is arranged at the second subgroup. In alternative, the blocking mechanism in an embodiment is at least in part arranged at the first subgroup, wherein in particular the actuator of the blocking mechanism is arranged at the first subgroup. Hence, at least a part of the blocking mechanism is arranged such that it is stationary during the operation of the weft feeder device. Thereby it is avoided that high masses have to be moved upon the wobbling movement during the operation of the weft feeder device. [0044] In case the actuator is arranged at the first subgroup, the movement or force is transferred to the second subgroup via a mechanism, for example a bellows that transfers the movement imposed by the actuator to a moveable blocking element arranged at the second subgroup for selectively moving the moveable blocking element into a first position, in which the moveable blocking element blocks a movement of the at least one guiding leg with respect to the guide structure, or a second position, in which the moveable blocking element does not block a movement of the at least one guiding leg with respect to the guide structure. In one embodiment, the blocking element is a disc with at least one inclined surface, which is rotated by means of the bellows. [0045] In one embodiment, in the release state the pressing element is moved apart from the associated guiding leg and does not contact the associated guiding leg in the release state. In advantageous embodiments, in the release state the contact force between the at least one pressing element and the guiding leg is reduced for a movement of the guiding leg in the bearing seat with reduced play between the guiding leg and the bearing seat. In other words, in the release state the pressing element still contacts the associated guiding leg. In order to avoid high frictional forces acting against the movement of the guiding leg in the release state, in one embodiment the pressing element is provided with a low-friction surface.

[0046] In an alternative embodiment, the at least one pressing element is a rolling element, in particular a resiliently mounted rolling element. The axis of the rolling element is arranged perpendicular to the movement direction of the associated guiding leg. In one embodiment, the axis of the rolling element is resiliently mounted in a bracket. In another embodiment, the axis is mounted fixed in position in a bracket, which bracket is resiliently mounted at the guide structure. [0047] According to one embodiment, the bearing seat comprises at least one stationary mounted rolling element, in particular a pair of stationary mounted rolling elements arranged at a distance to one another in the longitudinal direction of the guiding leg, wherein the resiliently mounted pressing element forces the guiding leg against the at least one first stationary mounted rolling element. [0048] According to one embodiment, the at least one drum segment comprises a first guiding leg and a second guiding leg, each extending in parallel to the movement direction of the drum segment at a lateral distance to one another, wherein the first guiding leg is mounted moveably in a first bearing seat of the guide structure and the second guiding leg is mounted moveably in a second bearing seat of the guide structure. [0049] In advantageous embodiments, the drum segment comprises a central rod extending in a radial direction with respect to the drum axis, wherein the first guiding leg extends at a first lateral distance to the central rod at a first side of the central rod and the second guiding leg extends at a second lateral distance to the central rod at a second side of the central rod. When providing a central rod, forces acting on the drum segment upon adjusting the position can be applied centrally on the drum segment and undesired torques or moments acting on the drum segment can be avoided upon driving the drum segment for adjusting a winding circumference. [0050] As mentioned above, in case only one guiding leg is provided, the central rod in particular is provided with a guiding portion. However, in case two guiding legs are provided, in one embodiment the central rod is mounted with a clearance space in the guide structure. In this embodiment, the central rod is not used for guiding the drum segment. Thereby, a mechanically overdetermined system is avoided.

[0051 ] According to a third, alternative or additional aspect, a weft feeder device comprising a winding drum with a drum axis and with an adjustable winding circumference for storing weft thread, a guide structure, and a drive mechanism is provided, wherein the winding drum comprises at least one drum segment with a central rod extending in a radial direction with respect to the drum axis, wherein the at least one drum segment is moveably mounted to the guide structure, wherein the drive mechanism cooperates with the central rod of the at least one drum segment for moving the at least one drum segment in the radial direction with respect to the drum axis upon adjusting the winding circumference of the winding drum, and wherein the at least one drum segment is further provided with at least one guiding leg guided by the guide structure, which at least one guiding leg extends at a distance in parallel to the central rod.

[0052] In one embodiment, the drive mechanism is manually-operated. In advantageous embodiments, the drive mechanism comprises a drive actuator. By means of the drive mechanism, forces are applied to the central rod for moving the drum segment in a radial direction with respect to the drum axis. When providing a central rod, forces acting on the drum segment upon adjusting the position are applied centrally on the drum segment and undesired torques or moments acting on the drum segment can be avoided. However, non-centrally applied forces acting on the drum segment, in particular when performing a wobbling movement for advancing weft threads, may cause an undesired displacement of the drum segment, in particular a rotation of the drum segment about the central rod. By providing the at least one additional guiding leg that extends at a distance in parallel to the central rod, the drum segment is prevented from rotating about the central rod.

[0053] The guiding leg in advantageous embodiments is provided with a circular cross-section for avoiding jamming. However, guiding legs having other cross-sections are also possible.

[0054] According to one embodiment, the at least one guiding leg extends at a lateral distance to the central rod. The central rod extends in a radial direction of the drum axis. In this case, the radial direction of the drum axis coincides with the longitudinal direction of the central rod and with the movement direction of the drum segment. The lateral direction is a direction perpendicular to the axial direction of the drum axis and perpendicular to the radial direction of the drum axis. A stability of the drum segment increases with a distance between the central rod and the at least one guiding leg. When providing the at least one guiding leg at a lateral distance to the central rod, a distance can be maximized by utilizing existing space. In advantageous embodiments, the at least one additional guiding leg is arranged at or close to a lateral end of the drum segment.

[0055] In addition or in alternative, in one embodiment the at least one guiding leg extends at an axial distance in the axial direction of the drum axis to the central rod. The axial distance is advantageous both for stabilizing the system and for allowing the central rod and the guiding legs of several drum segments mounted to a common guide structure to be moved over large distances without interference.

[0056] In one embodiment, the central rod is provided with a guiding portion, which guiding portion is guided by the guide structure. Such an embodiment is advantageous in case due to spatial limitations only one guiding leg is provided.

[0057] According to another embodiment, the at least one drum segment is provided with a first guiding leg and a second guiding leg guided by the guide structure, wherein the first guiding leg extends in parallel to the second guiding leg, and wherein the first guiding leg extends at a first lateral distance to the central rod at a first side of the central rod and the second guiding leg extends at a second lateral distance to the central rod at a second side of the central rod. By providing one guiding leg at each side of the central rod, the stability of the drum segment against any undesired displacement is further increased.

[0058] In case two guiding legs are provided, in one embodiment the first guiding leg and the second guiding leg are arranged at an axial distance to one another in the axial direction of the drum axis. As mentioned above, the axial distance is advantageous both for stabilizing the system and for allowing the central rod and the guiding legs of several drum segments mounted to a common guide structure to be moved over large distances without interference.

[0059] As mentioned above, in case only one guiding leg is provided, the central rod in particular is provided with a guiding portion. However, in case two guiding legs are provided, in one embodiment the central rod is mounted with a clearance space in the guide structure. In this embodiment, the central rod is not used for guiding the drum segment. Thereby, a mechanically overdetermined system is avoided. [0060] In one embodiment, the at least one guiding leg and/or the central rod is moveably mounted in parallel to the radial direction in a bearing seat of the guide structure, wherein the bearing seat is provided with at least one resiliently mounted pressing element, which pressing element is acting on the associated guiding leg or the associated central rod for reducing play between the associated guiding leg and the bearing seat or the associated central rod and the bearing seat. Providing a pressing element is advantageous in weft feeder devices having drum segments provided with a central rod and at least one guiding leg. In addition, providing a pressing element is also advantageous in other weft feeder devices, for example in weft feeder devices having drum segments comprising only a central rod and does not comprise additional guiding legs and/or in weft feeder devices having drum segments comprising two guiding legs and does not comprise a central rod, wherein one of the guiding legs is cooperating with a drive mechanism upon adjusting the winding circumference.

[0061 ] In one embodiment, the at least one guiding leg is mounted in the guide structure by using a plain bearing. When using a plain bearing, a material combination of the guiding legs and the guide structure and/or bearing sleeves provided at the guide structure for guiding the guiding legs is chosen suitably by the person skilled in the art for allowing a reliable guiding avoiding wear. In one embodiment, high frictional forces are avoided. In other embodiments, material combinations with high frictional forces are used for providing a self-locking system.

[0062] In alternative, the at least one guiding leg is mounted in the guide structure by using a rolling-element bearing. In the context of the application, a rolling-element bearing is defined as a bearing, wherein at least one rolling element, in particular rollers or wheels, is arranged between the guide structure and the guiding leg. The rolling element is arranged such that the movement of the guiding leg with respect to the guide structure causes the rolling element to roll about its axis. [0063] In one embodiment, the rolling-element bearing comprises at least one resiliently mounted rolling element. In the context of the application, resiliently mounted rolling element, shall be understood as meaning that the rolling element is mounted using a resiliently deformable material, wherein the rolling element is forced against the guiding leg by means of a restoring force of the resiliently deformable material and wherein the rolling element is moveable away from the guiding leg against the restoring force of the resiliently deformable material. By using a resiliently mounted rolling element, a play between the guiding leg and the bearing seat is further reduced and manufacturing tolerances are compensated. [0064] In one embodiment, a blocking mechanism operative to selectively take a blocking state and a release state is provided, wherein in the blocking state the blocking mechanism blocks a movement of the at least one guiding leg with respect to the guide structure. By means of the blocking mechanism, a movement of the guiding legs and, thus, the associated drum segment, with respect to the guide structure is avoided when the blocking mechanism is in its blocking state. In other words, in the context of the application, when the blocking mechanism is in its blocking state, the blocking mechanism blocks a movement of the at least one guiding leg with respect to the guide structure, and a movement is not possible or only possible when applying forces higher than forces expected in normal operation. On the other hand, when the blocking mechanism is in its release state a movement of the at least one guiding leg with respect to the guide structure is not blocked, and, thus possible, in particular it is easily possible for adjusting a winding circumference. Providing a blocking mechanism is advantageous in weft feeder devices having drum segments provided with a central rod and at least one guiding leg. In addition, providing a blocking mechanism is also advantageous in other weft feeder devices for example in weft feeder devices having drum segments comprising only a central rod and does not comprise additional guiding legs and/or in weft feeder devices having drum segments comprising two guiding legs and does not comprise a central rod, wherein one of the guiding legs is cooperating with a drive mechanism upon adjusting the winding circumference.

[0065] In advantageous embodiments, the blocking mechanism makes use of the at least one resiliently mounted rolling element, wherein the at least one resiliently mounted rolling element is forced against the associated guiding leg for blocking the associated guiding leg in a bearing seat, and wherein in the release state a contact force between the at least one resiliently mounted rolling element and the associated guiding leg is cancelled or reduced for a movement of the associated guiding leg in the bearing seat. In other embodiments, additional non- rotatable, resiliently mounted pressing elements are provided, which are forced against the guiding legs in the blocking state.

[0066] In one embodiment, the at least one drum segment is a resting drum segment. In advantageous embodiments, the at least one drum segment is a feeding drum segment and the guide structure is arranged for moving together with the feeding drum segment for advancing windings of the weft thread.

[0067] The drive mechanism for moving the drum segment in one embodiment comprises a rack-and-pinion-mechanism or a spindle. I n advantageous embodiments, the drive mechanism comprises a cam disk with a spiral groove, for example a spiral groove at one face, which spiral groove engages with the at least one engagement element provided at the central rod. The design of the spiral groove and/or the at least one engagement element is chosen suitable by the person skilled in the art for achieving a desired movement.

[0068] In one embodiment, the winding drum comprises a plurality of feeding drum segments, each feeding drum segment comprising a central rod and at least one guiding leg, wherein in particular the guiding legs of the plurality of feeding drum segments are guided in one common guide structure. The plurality of feeding drum segments is distributed about the circumference of the winding drum. In particular embodiments, three moveably arranged feeding drum segments and one drum segment stationary arranged on the guide structure are provided, which are arranged at intervals of 90° about the drum axis. [0069] In alternative or in addition, the winding drum comprises a plurality of resting drum segments, each resting drum segment comprising a central rod and at least one guiding leg, wherein in particular the guiding legs of the plurality of resting drum segments are guided in one common guide structure. In other embodiments, the winding drum comprises a plurality of feeding drum segments, each feeding drum segment comprising a central rod and at least one guiding leg, and a plurality of resting drum segments, wherein each resting drum segment comprises a central rod, but does not comprise an additional guiding leg.

[0070] In one embodiment, the winding drum comprises a plurality of resting drum segments mounted to a first guide structure, each resting drum segment comprising a central rod, and a plurality of feeding drum segments mounted to a second guide structure, each feeding drum segment comprising a central rod and at least one guiding leg, wherein the guiding legs of the plurality of the feeding drum segments are guided in the second guide structure, and wherein the second guide structure is mounted moveable with respect to the first guide structure to allow a wobbling movement of the second guide structure for advancing windings of the weft thread.

[0071 ] In particular, the resting drum segments and the feeding drum segments both are provided with at least one guiding leg moveably mounted in the respective first guide structure or second guide structure.

[0072] In one embodiment, the drive mechanism comprises a first cam disk and a second cam disk, the first cam disk comprising a first spiral groove engaging with at least one first engagement element, provided at the central rods of the plurality of resting drum segments and the second cam disk comprising a second spiral groove engaging with at least one second engagement element, provided at the central rods of the plurality of feeding drum segments. The first cam disk and the second cam disk are coupled such that a relative movement of the second cam disk with respect to the first cam disk is allowed in use such that the second cam disk can perform a wobbling movement together with the second guide structure for advancing windings of weft thread.

[0073] All aspects of the application can be individually implemented to provide a weft feeder device comprising a winding drum with an adjustable winding circumference allowing for a reliable positioning of a drum segment in a guide structure. In alternative, at least two of the first aspect, the second aspect and the third aspect of the application can be combined.

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] In the following, an embodiment of the invention will be described in detail with reference to the drawings. Throughout the drawings, the same elements will be denoted by the same reference numerals.

Fig. 1 shows a perspective view of a weft feeder device according to a first embodiment;

Fig. 2 shows a perspective view of the weft feeder device of Fig. 1 without a front cover;

Fig. 3 shows a cross sectional view of the weft feeder device of Fig. 1 without the front cover;

Fig. 4 shows an exploded view of a resting drum arrangement, a feeding drum arrangement and a drive mechanism for adjusting a winding circumference of the weft feeder device of Fig. 1 ;

Fig. 5 shows three resting drum segments and a drive mechanism of the weft feeder device of Fig. 1 ;

Fig. 6 shows a partially exploded front view of the parts of the weft feeder device of Fig. 5;

Fig. 7 shows a detail of the drive mechanism of the weft feeder device of Fig. 1 ;

Fig. 8 shows a perspective view of three resting drum segments, three feeding drum segments and a cam disk device of the drive mechanism of the weft feeder device of Fig. 1 ; Fig. 9 shows an explosive view of a feeding drum arrangement comprising three feeding drum segments and a guide structure of the weft feeder device of Fig. 1 seen from a rear side of the feeding drum arrangement; shows a perspective view of the feeding drum arrangement of Fig. 9; shows a perspective view of one feeding drum segment and the guide structure of the feeding drum arrangement of Fig. 9; shows a perspective view of the feeding drum segment of Fig. 1 1 and a cam disk of the drive mechanism for moving the feeding drum segment in a radial direction with respect to a drum axis upon adjusting the winding circumference of the winding drum; shows a perspective view of the feeding drum segment of Fig. 12 together with guide elements of a guide structure; shows a view of the arrangement of Fig. 13 seen in the direction of a guiding leg of the feeding drum segment; shows a perspective view seen from a rear side of a resting drum arrangement of the weft feeder device of Fig. 1 ; shows a perspective view of a resting drum segment and a guide structure of the resting drum arrangement of Fig. 15; shows a perspective view of the resting drum segment of Fig. 16 and a cam disk of the drive mechanism for moving the resting drum segment in a radial direction with respect to a drum axis upon adjusting the winding circumference of the winding drum; shows a perspective view of a feeding drum arrangement according to a second embodiment of a weft feeder device; Fig. 19 shows an exploded view of the feeding drum arrangement of Fig. 18; Fig. 20 shows a perspective view of a feeding drum segment and a guide structure of the feeding drum arrangement according to a third embodiment of a weft feeder device; and

Fig. 21 shows an exploded view of a feeding drum segment of a feeding drum arrangement according to a fourth embodiment of a weft feeder device.

DETAI LED DESCRI PTION OF EMBODIMENTS OF THE I NVENTION

[0075] Figs. 1 to 3 show a weft feeder device 1 in a perspective view with a front cover 3, a perspective view without the front cover 3, and a cross sectional view without the front cover 3, respectively. [0076] The weft feeder device 1 comprises a winding drum 5 onto which a rotating winding arm 6 winds a plurality of windings of a weft thread 7 (see Fig. 3). The rotating winding arm 6 rotates about the drum axis 9. In the embodiment shown in Figs. 1 to 3, the winding drum 5 comprises a resting drum arrangement 1 1 and a feeding drum arrangement 13. The weft feeder device 1 further comprises a housing 2 for a drive motor (not shown), a so-called stopper pin 4 for stopping a weft thread 7, a push-button 8 for activating the stopper pin 4 and a power switch 10 for powering the weft feeder device 1 .

[0077] Fig. 4 shows an exploded view of the resting drum arrangement 1 1 , the feeding drum arrangement 13 and a drive mechanism 15 for adjusting a winding circumference of the winding drum 5. The weft feeder device 1 comprises a first subgroup 12 and a second subgroup 14, wherein the second subgroup 14 is moved with respect to the first subgroup 12 for performing a wobbling movement for advancing windings of weft thread 7. In the following description, the first subgroup 12 comprises the resting drum arrangement 1 1 , whereas the second subgroup 14 comprises the feeding drum arrangement 13.

[0078] In the following description, directions and orientations of the device are defined as follows: "axial direction" is defined as a direction along with the drum axis 9; "forward end" or "front end" is defined to be the end of the weft feeder device 1 facing the weaving shed (not shown), which end is on right hand side of Fig. 1 ; "backward end" or "rear end" is defined as the opposite end of the weft feeder device 1 on left hand side of Fig. 1 . The terms "first" and "second" are used for distinguishing elements of the same or similar kind without defining any functional order of the respective elements. [0079] The resting drum arrangement 1 1 comprises four drum segments 17, 19, 21 , 23 arranged at intervals of 90° and a guide structure 25. One of the four drum segments 23, which in the embodiment shown is arranged at the top of the weft feeder device 1 , is stationary mounted to the guide structure 25. The remaining three drum segments 17, 19, 21 are moveably mounted to the guide structure 25. These drum segments are referred to as resting drum segments 17, 19, 21 , 23 in the context of the application. By means of the drive mechanism 15, the three moveably mounted resting drum segments 17, 19, 21 are moveable in the radial direction with respect to the drum axis 9 for adjusting the winding circumference of the winding drum 5. [0080] Similarly, the feeding drum arrangement 13 comprises four drum segments 27, 29, 31 , 33 arranged at intervals of 90° and a guide structure 35. One of the four drum segments 33, which in the embodiment shown is arranged at the top of the weft feeder device 1 , is stationary mounted to the associated guide structure 35 by means of a screw 24. The remaining three drum segments 27, 29, 31 are moveably mounted to the associated guide structure 35. These drum segments are referred to as feeding drum segments 27, 29, 31 , 33 in the context of the application. By means of the drive mechanism 15, the three moveably mounted feeding drum segments 27, 29, 31 are moveable in the radial direction with respect to the drum axis 9 together with the resting drum segments 17, 19, 21 upon adjusting the winding circumference of the winding drum 5. [0081 ] The moveable mounted resting drum segments 17, 19, 21 are only moved in a radial direction with respect to a drum axis 9 for adjusting the winding circumference of the winding drum 5, but are not moved upon winding or unwinding a weft thread 7 to or from the winding drum 5. The feeding drum segments 27, 29, 31 are moved in the radial direction with respect to the drum axis 9 upon adjusting the winding circumference of the winding drum 5 and are moved together with the guide structure 35 upon winding or unwinding a weft thread 7 to or from the winding drum 5 in order to advance at least a singular winding in parallel to the axial direction of the drum axis 9.

[0082] As best seen in Figs. 3 and 4, the weft feeder device 1 comprises a rotary shaft 37. The rotary shaft 37 drives the winding arm 6 and is driven by the drive motor (not shown) arranged in the motor housing 2. An eccentrically inclined sleeve 41 with an eccentric 39 is mounted to the rotary shaft 37 for rotation together with the rotary shaft 37. The guide structure 35 of the feeding drum arrangement 13 is mounted onto the sleeve 41 by means of bearings 40. The rotation of the rotary shaft 37 with the sleeve 41 causes a wobbling movement of the guide structure 35 with the drum segments 27, 29, 31 , 33 mounted thereon for advancing windings of weft thread 7.

[0083] The drum segments 17, 19, 21 , 23 of the resting drum arrangement 1 1 each comprise a plurality of bars 43 extending in parallel to the drum axis 9, which are arranged along a circumferential path of the winding drum 5 distributed in the circumferential direction. Similarly, the drum segments 27, 29, 31 , 33 of the feeding drum arrangement 13 each comprise a plurality of bars 45 extending in parallel to the drum axis 9, wherein these bars 45 are arranged between the bars 43 of the drum segments 17, 19, 21 , 23 to allow the bars 43, 45 to pass each other upon the wobbling movement of the feeding drum arrangement 13. [0084] The moveably arranged resting drum segments 17, 19, 21 are each provided with a central rod 47 and two guiding legs 51 , 53. The moveably arranged feeding drum segments 27, 29, 31 are each provided with a central rod 49 and two guiding legs 55, 57. In the embodiment shown, each of the guiding legs 51 , 53; 55, 57 has a circular cross-section. A circular cross- section is advantageous for avoiding jamming. In other embodiments, guiding legs having a different cross-section, for example a rectangular, square or oval cross-section, are provided.

[0085] Figs. 5 and 6 show the three resting drum segments 17, 19, 21 and the drive mechanism 15 used for causing a movement of the resting drum segments 17, 19, 21 for adjusting a winding circumference in more detail. As best seen in Figs. 5 and 6, the drive mechanism 15 comprises a drive actuator 67, a gear system 69 with a gear 68, a gear 70 and a worm gear 71 and a cam disk 59 with a spiral groove 61 at one face. The cam disk 59 is further provided with a pinion 65 cooperating with the worm gear 71 . The spiral groove 61 engages with a plurality of engagement elements 63 provided at the central rods 47. The engagement elements 63 in the embodiment shown are wing shaped. A rotation of the cam disk 59 causes a linear movement of the central rods 47 together with the associated resting drum segments 17, 19, 21 , wherein the sense of the direction of movement depends on the direction of rotation of the cam disk 59. The cam disk 59 in the following is also referred to as first cam disk 59.

[0086] As best seen in Fig. 3, the drive actuator 67 of the drive mechanism 15 is arranged stationary at the guide structure 25 of the resting drum arrangement 1 1 .

[0087] Fig. 7 shows the drive mechanism 15 without the cam disk 59 and with a mounting structure 73 for mounting the drive actuator 67 and the gear system 69 of the drive mechanism 15 to the guide structure 25 of the resting drum arrangement 1 1 (see Fig. 3). The gear 68 of the gear system 69 is mounted to an axis of the drive actuator 67 to rotate together with the axis of the drive actuator 67. By mounting the drive actuator 67 and the gear system 69 of the drive mechanism 15 to the guide structure 25 of the resting drum arrangement 1 1 , a movement of the drive mechanism 15 together with the resting drum segments 17, 19, 21 and/or together with the guide structure 35 of the feeding drum arrangement 13 upon a rotation of the rotary shaft 37 (see Fig. 3) is avoided.

[0088] As shown in Figs. 3 and 4, the moveably arranged feeding drum segments 27, 29, 31 of the feeding drum arrangement 13 are arranged to move together with the resting drum segments 17, 19, 21 upon adjusting the winding circumference. For this purpose, the drive mechanism 15 further comprises a second cam disk 75, coupled to the first cam disk 59 by means of a bellows cylinder 81 for rotating together with the first cam disk 59. The bellows cylinder 81 also allows to separate the resting drum segments 17, 19, 21 from the feeding drum segments 27, 29, 31 . The second cam disk 75, short also referred to simply as cam disk 75, is provided with a spiral groove 77 at one face engaging with a plurality of engagement elements 79 provided at a central rod 49 of the feeding drum segments 27, 29, 31 . A further bellows cylinder 82 is provided that forms a dust screen arranged between a base structure 16 of the weft feeder device 1 and the guide structure 35.

[0089] Fig. 8 shows a perspective view of the three moveably arranged resting drum segments 17, 19, 21 , the three moveably arranged feeding drum segments 27, 29, 31 and a cam disk device 76 of the drive mechanism 15 comprising the first cam disk 59, the second cam disk 75 and the bellows cylinder 81 . As can be best seen in Fig. 8, the first cam disk 59 and the second cam disk 75 are arranged such that the associated spiral grooves 61 , 77 point in opposite directions. The cam disk device 76 is arranged between the central rods 47 of the resting drum segments 17, 19, 21 and the central rods 49 of the feeding drum segments 27, 29, 31 , wherein the engagement elements 63, 79 are arranged at the surfaces of the central rods 47, 49 facing the cam disk device 76 for engaging with the associated spiral groove 61 , 77.

[0090] In accordance with the embodiment shown, a guiding system comprising the guide structures 25, 35 for the moveably arranged resting drum segments 17, 19, 21 as well as for the moveably arranged feeding drum segments 27, 29, 31 is separated from the drive mechanism 15. For guiding the drum segments in their movement upon adjusting the winding circumference, in the embodiment shown each moveably arranged resting drum segment 17, 19, 21 comprises two guiding legs 51 , 53 extending at a distance in parallel to the central rod 47 and each moveably arranged feeding drum segment 27, 29, 31 comprises two guiding legs 55, 57 extending at a distance in parallel to the central rod 49. [0091 ] In the embodiment shown, the two guiding legs 51 , 53; 55, 57 are each arranged at an axial distance in an axial direction of the drum axis 9 to the central rods 47, 49 as well as at a lateral distance to the central rod 47, 49 in a lateral direction perpendicular to the axial direction of the drum axis 9 and perpendicular to the longitudinal direction of central rod 47, 49. In the embodiment shown, the cam disk device 76 is arranged in an axial direction between the two guiding legs 51 , 53 of the resting drum segments 17, 19, 21 and the two guiding legs 55, 57 of the feeding drum segments 27, 29, 31 . In the embodiment shown, one of the two guiding legs, referred to as first guiding leg 51 ; 55 extends at a first lateral distance to the central rod 47; 49 at a first side of the central rod 47; 49 and the other one of the two guiding legs, referred to as second guiding leg 53; 57 extends at a second lateral distance to the central rod 47; 49 at a second side of the central rod 47; 49. In the embodiment shown, the first lateral distance at least essentially equals the second lateral distance.

[0092] The guide structure 35 of the feeding drum segments 27, 29, 31 is described in more detail with reference to Figs. 9 to 14, wherein Fig. 9 shows an explosive view of the feeding drum arrangement 13 without the stationary arranged drum segment 33 (see Fig. 4) seen from a rear side of the feeding drum arrangement 13; Fig. 10 shows a perspective view of the feeding drum arrangement 13; Fig. 11 shows a perspective view of one feeding drum segment 27 with the guide structure 35; Fig. 12 shows a perspective view of the feeding drum segment 31 and the cam disk 75 of the drive mechanism 15; Fig. 13 shows a perspective view of the feeding drum segment 31 together with guide elements of the guide structure 35 (see Fig. 4); Fig. 14 shows a view of the arrangement of Fig. 13 seen in the direction of the guiding legs 55, 57 of the feeding drum segment 31 , in particular seen in the direction P shown in Fig. 13.

[0093] As best seen in Figs. 9 and 10, the guide structure 35 is provided with a screw hole 84 for mounting the stationary arranged drum segment 33 (see Fig. 4) of the feeding drum arrangement 13 fixed in position to the guide structure 35.

[0094] The feeding drum segments 27, 29, 31 are moveably mounted to the guide structure 35. In the embodiment shown, the central rods 49 of the feeding drum segments 27, 29, 31 each are mounted with a clearance space in a groove 83 of the guide structure 35.

[0095] Each feeding drum segment 27, 29, 31 is guided by means of the first guiding leg 55 and the second guiding leg 57. In the embodiment shown, the first guiding leg 55 and the second guiding leg 57 of the feeding drum segments 27, 29, 31 are each guided in the guide structure 35 by using a rolling-element bearing 85, 87, referred to as first rolling-element bearing 85 and second rolling-element bearing 87 in the following. The rolling-element bearing 85 has one bearing seat 86 for the first guiding leg 55 and the rolling-element bearing 87 has two bearing seats 88 for the second guiding leg 57.

[0096] As best seen in Figs. 12, 13 and 14, the first rolling-element bearing 85 comprises one rolling element 89 and a bracket 91 arranged opposite to the rolling element 89. The rolling element 89 and the bracket 91 together form a bearing seat 86. The rolling element 89 is mounted via a holder 102 by means of a cantilever 92 to the guide structure 35. The bracket 91 is mounted to the guide structure 35. The surface contour of the rolling element 89 is provided with a groove adapted to the circular cross-section of the guiding leg 55. The bracket 91 in an advantageous embodiment has a low friction surface 100 for contacting the guiding leg 55. For this purpose, in one embodiment the bracket 91 is made of a material having a low friction coefficient in combination with a material chosen for the guiding leg 55. In other embodiments, the bracket 91 is provided with a coating or surface layer at the surface contacting the guiding leg 55.

[0097] The second rolling-element bearing 87 comprises four rolling elements 93, 94 arranged in pairs at opposite sides of the second guiding leg 57. Each pair of rolling elements 93, 94 forms a bearing seat 88. The rolling elements 93, 94 of each pair of rolling elements are arranged at an axial distance to one another in the longitudinal direction of the guiding leg 57. The axial distance between the rolling elements 93, 94 is the same for both pairs and the two pairs are arranged such that the second guiding leg 57 is guided by two opposing rolling elements 93, 94 in two areas in its longitudinal direction. In the example, the surface contour of each of the rolling elements 93, 94 is provided with a groove adapted to the circular cross- section of the guiding leg 57. The pair of rolling elements 93 arranged at a rear side of the guiding leg 57 is mounted to the guide structure 35 by means of a longitudinal beam 95 via a holder 104. The pair of rolling elements 94 arranged at a front side of the guiding leg 57 is mounted to a support 90 of the guide structure 35.

[0098] The combination of the rolling-element bearings 85, 87 shown in Figs. 10 to 14 is advantageous for allowing a reliable guiding of the two guiding legs 55, 57, in particular a guiding without or with only little play. However, it will be understood by the person skilled in the art, that the invention is not limited to the combination of rolling-element bearings shown and/or the embodiments of the rolling-element bearings shown. Various other rolling-element bearings and/or combinations of rolling-element bearings are conceivable, wherein for example more than two pairs of rolling elements, for example three or four pairs of rolling elements are arranged about the periphery of a guiding leg and/or wherein rolling elements of different shapes are used. For example, a rolling-element bearing can be formed by three rolling elements that are arranged at angles of 120° about the periphery of a guiding leg. Further, in one embodiment only one guiding leg is guided by using a rolling-element bearing, whereas the other guiding leg is guided by using a plain bearing.

[0099] For further reducing play between the bearing seat 86 and the associated first guiding leg 55, in the embodiment shown by means of the cantilever 92 the rolling element 89 is resiliency mounted to the guide structure 35, in particular the resilient cantilever 92 presses the rolling element 89 against the guiding leg 55. Hence, the resiliency mounted rolling element 89 functions as a pressing element 89 acting on the associated guiding leg 55 for further reducing play between the associated guiding leg 55 and the bearing seat 86. [0100] Similarly, for reducing play between the bearing seats 88 and the associated second guiding leg 57, in the embodiment shown the rolling elements 93 arranged at the rear side of the guiding leg 57 are resiliency mounted to the guide structure 35 by means of the beam 95, in particular the resilient longitudinal beam 95 presses the rolling elements 93 against the guiding leg 57. Hence, the resiliency mounted rolling elements 93 function as pressing elements 93 acting on the associated guiding leg 57 for further reducing play between the associated guiding leg 57 and the bearing seats 88.

[0101 ] In an alternative embodiment, the support 90 for the rolling elements 94 of the rolling element bearing 87 is resiliency mounted for forcing the rolling elements 94 towards the associated rolling elements 93 and/or the bracket 91 of the rolling element bearing 85 is resiliency mounted for forcing the bracket 91 towards the rolling element 89 arranged opposite the bracket 91 . In still another embodiment, all bearings are designed as plain bearings comprising a resiliency mounted element for reducing play.

[0102] The guide structure 25 of the resting drum segments 17, 19, 21 is described in more detail with reference to Figs. 15 to 17, wherein Fig. 15 shows a perspective view from a rear side of the resting drum arrangement 1 1 of the weft feeder device 1 of Fig. 1 , Fig. 16 shows a perspective view of the resting drum segment 17 and the guide structure 25 from a front of the weft feeder device 1 , and Fig. 17 shows a perspective view of the resting drum segment 17 and the cam disk 59 of the drive mechanism 15 for moving the resting drum segment 17 for adjusting the winding circumference of the winding drum 5. The stationary arranged resting drum segment 23 (see Fig. 4) is not shown in Figs. 15 to 17.

[0103] The resting drum segments 17, 19, 21 are moveably mounted to the guide structure 25. As described above, for adjusting the winding circumference, the drive mechanism 15 (see Fig. 5) cooperates with engagement elements 63 provided at the central rods 47 (see Fig. 15). In the embodiment shown, the central rods 47 of the resting drum segments 17, 19, 21 are mounted with a clearance space in a groove 96 of the guide structure 25. The resting drum segments 17, 19, 21 are guided by means of the first guiding leg 51 and the second guiding leg 53. The guide structure 25 is provided with six cavities 97 for forming bearing seats 99 for the guiding legs 51 , 53 of the three resting drum segments 17, 19, 21 . The guiding legs 51 , 53 are mounted in the bearing seats 99 by using a plain bearing, wherein in the embodiment shown two bearing sleeves 101 are arranged in each bearing seat 99 for enhancing the guiding and reducing frictional forces. [0104] The cam disk 59 (see Fig. 17) is rotatable supported on the guide structure 25 by means of a mounting sleeve 103.

[0105] In alternative or in addition, in one embodiment of a feeding drum arrangement 13 or a resting drum arrangement 1 1 , a blocking mechanism 98 operative to selectively take a blocking state and a release state is provided, wherein in the blocking state the blocking mechanism 98 blocks a movement of at least one of the guiding legs 51 , 53; 55, 57 along the guide structure 25; 35. Such a blocking mechanism is in particular advantageous at a feeding drum arrangement 13 for avoiding a relative movement of the feeding drum segments 27, 29, 31 with respect to the guide structure 35 upon a wobbling movement of the feeding drum segments 27, 29, 31 for advancing windings of weft thread 7 (see Fig. 3). [0106] In one embodiment, the blocking mechanism comprises an element for blocking a rotation of at least one of the rolling elements 89, 93 provided at the feeding drum arrangement 13 shown in Figs. 1 to 14. In another embodiment, the blocking mechanism comprises a pressing element forced against at least one of the guiding legs 55, 57 for blocking a movement of the guiding leg 55, 57 of the feeding drum arrangement 13 shown in Figs. 1 to 14. In still another embodiment, one of the resiliently mounted rolling elements 89, 93 and/or the resiliently mounted support 90 or bracket 91 functions also as a blocking element, wherein a force applied by the rolling element 89, 93 is chosen sufficiently large to block a movement of the guiding leg 55, 57 in the associated bearing seat 86, 88. In this case, an actuator device is provided, short also referred to actuator, which is selectively operable for cancelling or at least reducing the force applied by the rolling element to selectively allow a movement upon adjusting the winding circumference.

[0107] Figs. 18 and 19 show a feeding drum arrangement 13 according to a second embodiment of a weft feeder device 1 in a perspective view and an explosive view, respectively. The second embodiment is similar to the first embodiment and the same reference signs are used for the same or similar elements. The feeding drum arrangement 13 according to the second embodiment also comprises three feeding drum segments 27, 29, 31 moveably mounted to a guide structure 35. Similarly, the first embodiment, the feeding drum arrangement 13 according to a second embodiment comprises a fourth drum segment 33 (see Fig. 4), which is stationary mounted to the guide structure 35. Each feeding drum segment 27, 29, 31 comprises two guiding legs 55, 57. The feeding drum segment 27, 29, 31 in accordance with one aspect of the invention in addition comprises a central rod 49 arranged between the guiding legs 55, 57, which cooperates with a drive mechanism for moving the feeding drum segments 27, 29, 31 upon adjusting a winding circumference.

[0108] In accordance with the second embodiment, the guiding legs 55, 57 of the feeding drum segments 27, 29, 31 are guided in the guide structure 35 using plain bearings. The guide structure 35 for this purpose is provided with six cavities 105 for forming bearing seats 106 for the guiding legs 55, 57 of the three feeding drum segments 27, 29, 31 . For allowing a movement of the guiding legs 55, 57 in a longitudinal direction along the bearing seat 106, the guiding legs 55, 57 are mounted with play in the bearing seat 106. For reducing play and/or for blocking at least one of the two guiding legs 55, 57 of each feeding drum segment 27, 29, 31 in the associated bearing seats 106, pressing elements 107 are provided, which are resiliently mounted using spring elements 109. [0109] In the embodiment shown, the guide structure 35 comprises a main body 1 15 and a cover 1 17, wherein a plate element 1 13 is moveably mounted between the main body 1 15 and the cover 1 17. The plate element 1 13 is guided to move in a direction parallel to a central drum axis 9 (see Fig. 3) by means of pins 1 1 1 projecting from the main body 1 15. The pressing elements 107 are fixedly mounted to the plate element 1 13, wherein the spring elements 109 force the plate element 1 13 towards the main body 1 15, thereby forcing the pressing elements 107 against the guiding legs 57. The cover 1 17 is mounted to the main body 1 15 using fixation elements 1 12 (see Fig. 18).

[01 10] Depending on the restoring force of the spring elements 109, the pressing elements 107 act on the associated guiding legs 57 either for reducing play between this guiding leg 57 and its bearing seat 106 or for blocking a relative movement of the guiding leg 57 and the guide structure 35.

[01 1 1 ] In case the restoring force of the spring elements 109 is chosen sufficiently large to block a movement of the guiding leg 57 with respect to the guide structure 35, a blocking mechanism 98 is provided, which is selectively operable to take a blocking state or a release state, wherein in the blocking state the pressing elements 107 are forced against the guiding legs 57 for blocking a movement of the guiding legs 57 in the associated bearing seats 106, and wherein in the release state a contact force between the pressing elements 107 and the guiding legs 57 is cancelled or at least reduced for allowing a movement of the guiding legs 57 in the bearing seat 106. The blocking mechanism 98 in advantageous embodiments comprises at least one actuator 122, in particular a plurality of actuators, wherein by means of the at least one actuator 122 the plate element 1 13 is moved against the force of the spring elements 109 away from the main body 1 15 towards the cover 1 17. In the embodiment shown in Fig. 19, the actuators 122 are for example piezo-electrical actuators that are mounted at the main body 1 15 and that can expand in a direction towards the plate element 1 13 to move the plate element 1 13 away from the main body 1 15.

[01 12] In one embodiment, the drive actuator 67 of the drive mechanism 15 (see Fig. 7) is used to cause a release state of the blocking mechanism 98, wherein when activating the drive mechanism 15 to adjust the winding circumference, the blocking mechanism 98 takes the release state. In other embodiments, a separate actuator for the blocking mechanism 98 is provided.

[01 13] Fig. 20 shows a perspective view of a feeding drum segment 27 and a guide structure 35 of a feeding drum arrangement 13 according to a third embodiment of a weft feeder device 1 . The third embodiment is similar to the first and second embodiment and the same reference signs are used for the same or similar elements. The feeding drum arrangement 13 according to the third embodiment also comprises three feeding drum segments 27, 29, 31 moveably mounted to the guide structure 35, wherein in Fig. 20 only one feeding drum segment 27 is shown. Further, similar to the first embodiment, the feeding drum arrangement 13 according to a third embodiment comprises a fourth drum segment 33 (see Fig. 4), which is stationary mounted to the guide structure 35. Each feeding drum segment 27, 29, 31 comprises a central rod 49 and two guiding legs 55, 57 arranged at the sides of the central rod 49. The central rod 49 cooperates with a drive mechanism 15 (see Fig. 4) for moving the feeding drum segments 27, 29, 31 upon adjusting a winding circumference. Similar to the second embodiment, in accordance with the third embodiment, the guiding legs 55, 57 are guided using plain bearings, in particular bearing seats 106.

[01 14] The guide structure 35 for this purpose is provided with six cavities 105 for forming bearing seats 106 for the guiding legs 55, 57 of the three feeding drum segments 27, 29, 31 . For allowing a movement of the guiding legs 55, 57 in a longitudinal direction along the bearing seats 106, the guiding legs 55, 57 are mounted with play in the bearing seats 106. For reducing play and/or for blocking at least one of the two guiding legs 55, 57 of each feeding drum segment 27, 29, 31 in the associated bearing seats 106, rolling elements 1 19 are provided, which are resiliently mounted using spring elements, in particular are mounted to the guide structure 35 by means of a resilient cantilever 92, and which act on the guiding leg 57 for forcing the guiding leg 57 against the associated bearing seat 106.

[01 15] As described above, depending on the restoring force of the spring elements, for example the resilient cantilever 92 in the embodiment of Fig. 20, the rolling elements 1 19 act on the associated guiding legs 57 either for reducing play between this guiding leg 57 and its bearing seat 106 or for blocking a relative movement of the guiding leg 57 and the guide structure 35. In one embodiment, the rolling elements 1 19 are forced against the guiding legs 57 for reducing play, wherein in addition for blocking a movement of the associated guiding leg 57 in the bearing seat 106 a rotation of the rolling element 1 19 is blocked. In the embodiment of Fig. 20, at least one actuator 124, for example piezo-electrical actuators, is mounted at the cantilever 92 facing the guide structure 35 for reducing the force the cantilever 92 acting on the rolling element 1 19. Hence, the resiliently mounted rolling element 1 19, similar to the resiliently mounted rolling elements 89, 93 shown in Figs. 10 to 14, functions as a pressing element 1 19 acting on the associated guiding leg 55, 57.

[01 16] Fig. 21 shows an explosive view of a feeding drum segment 27 of a feeding drum arrangement 13 according to a fourth embodiment of a weft feeder device 1 in accordance with the first aspect and/or the second aspect of the application, wherein in contrast to the previous embodiments, the feeding drum segment 27 is not provided with a central rod. A guide structure of the feeding drum arrangement according to a fourth embodiment is similar to the guide structure 35 shown in Figs. 18 and 19 and comprises a main body 1 15 (see Fig. 19) provided with bearing seats 106 and a cover 1 17, wherein only the bearing seats 106 and the cover 1 17 are shown in Fig. 21.

[01 17] In accordance with the fourth embodiment, the feeding drum segment 27 comprises a first guiding leg 120 and a second guiding leg 57. The first guiding leg 120 is provided with a rack 121 cooperating with a pinion (not shown) for driving the feeding drum segment 27 to move with respect to the guide structure. The pinion can be similar to the pinion known from WO 2015/16961 1 A1 . In one embodiment, the first guiding leg 120 further comprises a guiding portion, which is distinct to the rack 121 . In other embodiments, the first guiding leg is only guided by the rack 121 . [01 18] The second guiding leg 57 is guided in the guide structure using a plain bearing in a bearing seat 106. For reducing play and/or for blocking the movement of the second guiding leg 57 with respect to the bearing seat 106, a blocking mechanism 98 having a pressing element 107 that acts on the guiding leg 57 associated to the bearing seats 106 is provided. The pressing element 107 is fixed to a plate element 1 13, which plate element 1 13 is resiliently mounted to the main body 1 15 (see Fig. 19) using spring elements 109.

[01 19] In the embodiment shown, the pressing elements 107 of three feeding drum segments are mounted to the plate element 1 13, which plate element 1 13 is moveably mounted between the main body 1 15 (not shown) and the cover 1 17 of the guide structure. The spring elements 109 force the plate element 1 13 towards the main body 1 15, thereby forcing the pressing elements 107 against the guiding legs 57.

[0120] Depending on the restoring force of the spring elements 109, the pressing elements 107 act on the associated guiding legs 57 either for reducing play between this guiding leg 57 and its bearing seat 106 or for blocking a relative movement of the guiding leg 57 and the guide structure 35.

[0121 ] As described above, in case the restoring force of the spring elements 109 is chosen sufficiently large to block a movement of the guiding leg 57 with respect to the guide structure 35, a blocking mechanism 98 is provided, which is selectively operable to take a blocking state or a release state, wherein in the blocking state the pressing elements 107 are forced against the guiding legs 57 for blocking a movement of the guiding legs 57 in the associated bearing seats 106, and wherein in the release state a contact force between the pressing elements 107 and the guiding legs 57 is cancelled or at least reduced for allowing a movement of the guiding legs 57 in the bearing seat 106.

[0122] In the embodiment shown, the pressing elements 107 form part of a blocking mechanism 98, which comprises an actuator 123. By means of the actuator 123, the plate element 1 13 is moved against the force of the spring elements 109 away from the main body 1 15, in particular the bearing seats 106, towards the cover 1 17. The actuator 123 is for example an electromagnet, which is arranged inside the cover 1 17 and which is powered to attract a plate element 1 13 made of a suitable material in order to force the plate element 1 13 with pressing elements 107 away from the main body 1 15 with associated bearing seats 106.

[0123] The blocking mechanism 98 is in particular used to act on guiding legs 55, 57 of the second subgroup 14 performing a wobbling movement. In this case masses of the blocking mechanism 98 that have to be moved upon the wobbling movement during the operation of the weft feeder device 1 are in particular as low as possible. In an alternative (not shown), a blocking mechanism 98 can be used to act on guiding legs 51 , 53 of the first subgroup 12, wherein in particular most parts of the blocking mechanism are arranged stationary at the first subgroup 12.

[0124] In another embodiment (not shown), the bearing seat 106 further comprises at least one stationary mounted rolling element, in particular a pair of stationary mounted rolling elements arranged at a distance to one another in the longitudinal direction of the second guiding leg 57, wherein the resiliently mounted pressing element 107 forces the second guiding leg 57 against the at least one stationary mounted rolling element. With this arrangement, the rolling elements can also be evenly distributed about the periphery of the guiding leg.