EP3679186B1 - Thread braking device for a weft feeder device - Google Patents
Thread braking device for a weft feeder device Download PDFInfo
- Publication number
- EP3679186B1 EP3679186B1 EP18746720.4A EP18746720A EP3679186B1 EP 3679186 B1 EP3679186 B1 EP 3679186B1 EP 18746720 A EP18746720 A EP 18746720A EP 3679186 B1 EP3679186 B1 EP 3679186B1
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- EP
- European Patent Office
- Prior art keywords
- support structure
- braking
- thread
- braking device
- band
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 239000004033 plastic Substances 0.000 description 3
- 229920003023 plastic Polymers 0.000 description 3
- 230000000717 retained effect Effects 0.000 description 3
- 238000009941 weaving Methods 0.000 description 3
- 230000001174 ascending effect Effects 0.000 description 2
- 229920002635 polyurethane Polymers 0.000 description 2
- 239000004814 polyurethane Substances 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 229920002430 Fibre-reinforced plastic Polymers 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
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- 239000000428 dust Substances 0.000 description 1
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- 230000005484 gravity Effects 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910001092 metal group alloy Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
Images
Classifications
-
- D—TEXTILES; PAPER
- D03—WEAVING
- D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
- D03D47/00—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms
- D03D47/34—Handling the weft between bulk storage and weft-inserting means
- D03D47/36—Measuring and cutting the weft
- D03D47/361—Drum-type weft feeding devices
- D03D47/364—Yarn braking means acting on the drum
- D03D47/366—Conical
Definitions
- the invention relates to a thread braking device for a weft feeder device with a withdrawal rim, wherein the thread braking device comprises a braking band which cooperates with the withdrawal rim of the weft feeder device to form a weft thread braking zone.
- the invention also relates to a weft feeder device comprising a thread braking device.
- the braking band of a thread braking device for a weft feeder device cooperates with a braking surface at a withdrawal rim of the thread braking device for forming a braking zone.
- the braking band contacts the withdrawal rim along a circular line or along a circular band-shaped zone.
- the extent to which the thread braking device in the braking zone resists deformation in a radial direction of the weft feeder device in response to a force exerted by a weft thread arranged between the braking band and the withdrawal rim is referred to as radial stiffness.
- a thread braking device having a radially deformable braking band with the shape of a frusto-cone is shown in EP 0 534 263 B1 .
- Said braking band is supported by a frusto-conical shaped support structure which is radially deformable but axially stiff.
- the support structure is held by a holder using a spring assembly in a position such that the braking band is forced against the withdrawal rim by the restoration force of the spring assembly.
- EP 0 867 390 A2 shows a thread braking device, wherein an axial movement of a braking body away from the withdrawal rim is limited using a retention ring made of elastomeric material.
- the braking body is held in a support via springs.
- the retention ring is mounted to a threaded ring, which engages with the support. A position of the threaded ring together with the retention ring can be adjusted using a knob.
- a thread braking device is further shown for example in EP 0 963 335 B1 , wherein the thread braking device comprises a braking band floatingly supported by a support structure.
- the braking band is arranged inside the support structure, wherein an elastic element is arranged between the braking band and the support structure.
- a radial stiffness in the braking zone is determined by the radial stiffness of the braking band and the elastic element.
- the elastic element can be exchanged for changing the radial stiffness of the thread braking device, for example for a use of the device with different types of weft threads.
- a thread braking device for a weft feeder device with a withdrawal rim comprising a annular braking band with a frusto-conical shape and a braking surface adapted for contacting the withdrawal rim of the weft feeder device for forming a braking zone for a weft thread withdrawn from the weft feeder device, and a support structure, wherein the braking band is supported by the support structure, wherein the support structure is at least partly elastically deformable by an axial force exerted on the support structure, wherein the support structure is provided with at least one stiffening element surrounding the braking band at a rear side of the braking band opposite to the braking surface, in particular a circumferential stiffening element, and wherein in a non-deformed state of the support structure the braking band is arranged at a distance of the stiffening element and by exerting an axial force on the support structure, the support structure is deformable so that the
- the support structure comprises a retaining element for retaining the braking band.
- the retaining element consists of a retaining ring made of an elastically deformable material, in particular a plastic material, more particular polyurethane.
- the retaining element is deformed, thereby causing a movement of the braking band towards the stiffening element until the braking band is supported by the stiffening element.
- with “is supported by” is not only meant that the braking band directly abuts against the stiffening element, but the braking band can also indirectly abut against the stiffening element via the retaining element that is arranged between the braking band and the stiffening element.
- the radial stiffness is dependent on the deformation of the support structure, more in particular dependent on the fact whether or not the braking band is supported by the stiffening element, in other words dependent on the fact that the braking band is or is not supported by the stiffening element.
- the braking band is made for example of stainless steel or a plastic material, in particular a fiber-reinforced plastic material.
- the thickness of the braking band is also chosen by the person skilled in the art and is for example between about 0,004 mm and about 1 mm. Depending on the material chosen, other braking bands having a higher or lower thickness may also be used.
- the radial stiffness in the braking zone is determined by the radial stiffness of the braking band.
- the radial stiffness in the braking zone is also determined by the radial stiffness of the stiffening element.
- the radial stiffness of the thread braking device is adjustable. Therefore, the thread braking device is suitable for a large number of different types of weft thread.
- the thread braking device can be set to have a low radial stiffness.
- the thread braking device can be set to have a high radial stiffness. In this way, a uniform low force can be exerted over the entire circumference of the braking zone for weak threads and it is still possible to transfer sufficient force on the thread for strong threads.
- the radial stiffness is determined amongst others by the axial position of the support structure, more in particular by the fact that whether or not the braking band is supported by the stiffening element.
- a stiffening element having a circumferential contour is also referred to as a circumferential stiffening element.
- the at least one stiffening element has a continuous circumferential contour, and is also referred to as a continuous circumferential stiffening element.
- the continuous circumferential contour is advantageous for a uniform radial stiffness along the entire braking zone.
- the stiffening element has a discontinuous circumferential contour, wherein the circumferential contour is formed by a number of stiffening parts arranged at regular short distance from one another, that form together the stiffening element.
- the support structure comprises a cage with a frusto-conical shape, wherein the braking band is arranged inside the cage.
- the term cage is used for any frusto-conical shaped body enclosing the braking band.
- the cage may be provided with a plurality of bars or any other type of open framework to avoid dust accumulation in the cage.
- the cage having a frusto-conical shape is arranged with its smaller end facing away from the withdrawal rim.
- the larger end of the cage extends beyond the braking band, wherein the larger end of the cage functions as a thread guiding element for guiding the weft thread towards the braking zone.
- the stiffening element and the cage are formed separately and the stiffening element is attached to the cage, for example glued to the cage or clamped in a clamping structure of the cage.
- the at least one stiffening element is formed integrally with the cage, in particular the at least one stiffening element is formed by a contour of the cage.
- the cage is for example made of a plastic material, wherein the at least one stiffening element is formed with the cage without requiring any additional assembly step.
- several stiffening elements are provided, wherein depending on the deformation, the braking band is supported by at least one selected one of the stiffening elements.
- a uniform force application to the support structure in one embodiment, several pressing elements are provided, which are evenly distributed about the circumference of the support structure. In preferred embodiments, the force is exerted centrally.
- a pressing ring is provided at a smaller end of the cage for exerting an axial force on the support structure.
- the retaining element and the cage together form the support structure.
- the retaining element and the cage are formed separately. This allows using different materials with different properties for the cage and the retaining element.
- the braking band is glued to the retaining element.
- the braking band is inserted in a retaining slot provided in the retaining element.
- the braking band is floatingly retained in the retaining slot, so that the braking band can position itself with respect to the withdrawal rim.
- the retaining element i.e.
- the retaining ring in one embodiment extends beyond the rear side of the braking band opposite the braking surface, wherein when the braking band is supported by the stiffening element, the portion of the retaining element provided at the rear side of the braking band is arranged between the braking band and the stiffening element.
- the radial stiffness in the braking zone is also influenced by the radial stiffness of the retaining element, wherein preferably the radial stiffness of the retaining element is comparatively low and only neglectably influences the overall radial stiffness in the braking zone when the braking band is arranged at a distance of the stiffening element as well as when the braking band is supported by the stiffening element.
- the cage is made of a suitable material and designed such that the cage has a high axial stiffness and is not or only neglectably deformed by the axial forces exerted.
- the force in one embodiment is exerted by a spring assembly, wherein for example the force and the degree of deformation are settable by choosing an axial position of the support structure with respect to the withdrawal rim.
- an actuator is provided for exerting an axial force on the support structure.
- the actuator is arranged at an end of the support structure opposite to the end facing the withdrawal rim. Hence, by means of the actuator, the support structure is displaceable towards the withdrawal rim. Due to the contact of the braking band with the withdrawal rim, the support structure is deformed in response to the force exerted by the actuator.
- the actuator allows for an automated adaption of the radial stiffness.
- the braking band In case only a low force is exerted by the actuator, the braking band is forced against the withdrawal rim without any or with only a neglectable deformation of the support structure, in particular of the retaining element of the support structure. Hence, the braking band is not supported by the stiffening element and the radial stiffness of the braking zone is low. In case a force exceeding a defined threshold is exerted, the support structure, in particular the retaining element of the support structure is deformed and the braking band is supported by the stiffening element or one of a plurality of stiffening elements resulting in an increased radial stiffness. In other words, the thread braking device has a variable radial stiffness as function of the axial position of the support structure with respect to the withdrawal rim.
- the actuator is force-controlled or position controlled, in particular the actuator is force-feed-back controlled or position-feed-back controlled.
- a sensor is provided for determining the position of the support structure.
- the actuator is a magnetic coil actuator, which is force-controlled so that no further sensor device is required.
- the actuator comprises a rotor suspended by spring devices, that allow that the rotor moves in an axial direction, but not in a direction perpendicular to the axial direction.
- the thread braking device in one embodiment comprises an interface for selecting a force exerted by the actuator.
- the interface in preferred embodiments is designed easy to use. For example, N preselected positions and/or N preselected profiles of positions and/or N preselected force values and/or N preselected profiles of force values are stored in the thread braking device in an ascending to descending order and the operator selects a number between 0 and N for having a higher or lower radial stiffness without having to know the position or force associated with the selected number.
- the interface comprises for example a turnable knob for selecting the radial stiffness between a level 0 and a level N, with 0 being the lowest level of radial stiffness and N being the highest level of radial stiffness.
- the interface in one embodiment also comprises a display to show the selected level.
- a profile of positions and/or profile of force values for example can be determined in function of the angular position of the main axis of the weaving machine.
- the profiles can be chosen such that the force values are relatively high when a weft thread is taken up and/or released by a gripper, and are relatively low when the weft thread does not move or is moved with an almost constant velocity by a gripper.
- the actuator is further operable to move the braking band away from the withdrawal rim.
- the actuator it is also possible to move the braking band away from the withdrawal rim for example for inserting a weft thread after a thread breakage or when changing a braking band.
- the support structure is exclusively supported by the actuator, for example mounted with its rear end to the actuator.
- the thread braking device further comprises a holder, wherein the support structure is moveably in the axial direction held by the holder.
- a stability of the system is increased.
- the holder also allows to counter the gravity force and to improve the central arrangement of the thread braking device with respect to the winding drum.
- the support structure is held by the holder using a spring assembly.
- the restoration force of the spring assembly in one embodiment also contributes to the deformation of the support structure.
- the spring assembly is designed not to or to only neglectably influence the deformation of the support structure.
- a weft feeder device comprising a winding drum with a withdrawal rim and a thread braking device arranged in front of the withdrawal rim
- the thread braking device comprises a annular braking band with a frusto-conical shape and a braking surface adapted for contacting the withdrawal rim for forming a braking zone for a weft thread withdrawn from the weft feeder device, and a support structure, wherein the braking band is supported by the support structure, wherein the support structure is at least partly elastically deformable by an axial force exerted on the support structure, wherein the support structure is provided with at least one stiffening element surrounding the braking band at a rear side of the braking band opposite to the braking surface, in particular a circumferential stiffening element, and wherein in a non-deformed state of the support structure the braking band is arranged at distance of the stiffening element and by exerting an axial force on the support structure, the support structure is de
- Fig. 1 shows a perspective view of a weft feeder device 1 with a thread braking device 3.
- Fig. 2 shows a detail of Fig. 1 .
- the weft feeder device 1 comprises a winding drum 5 on which a rotating winding arm 6 winds a plurality of turns or windings of a weft thread 7.
- the rotating winding arm 6 rotates about a drum axis 9.
- a thread guide 11 is arranged in front of the thread braking device 3 .
- a rounded front end of the winding drum 5 that extends uninterrupted or continuous over the circumference of the front end of the winding drum 5, is referred to as withdrawal rim 13.
- the thread braking device 3 shown in Fig. 2 comprises a circumferential braking band 15, a support structure 17 having an annular shape, a holder 19, a pressing ring 21, a spring assembly 22 with a plurality of spring elements 23, and an actuator 25.
- the support structure 17 comprises a cage 31 and a retaining element 33 that is mounted on an outer support ring 18 of the cage 31.
- the retaining element 33 retains the braking band 15.
- the retaining element 33 is shaped as a retaining ring, and the circumferential braking band 15 is shaped as an uninterrupted or continuous circumferential braking band.
- the weft thread 7 is withdrawn via the thread guide 11 from the winding drum 5, wherein during withdrawal the weft thread 7 withdrawn is moving about the withdrawal rim 13 in a braking zone 16 between the withdrawal rim 13 and the braking band 15.
- a braking surface 14 of the braking band 15 contacts the withdrawal rim 13 in order to form a braking zone 16 for the weft thread 7 withdrawn from the weft feeder device 1.
- the braking band 15 is made of wear resistant material, e.g. of a metal or a metal alloy, in particular stainless steel, and has the shape of a frusto-conical element.
- the braking band 15 is resiliently deformable in a radial direction of the drum axis 9, but preferably has a high stiffness in the axial direction. As will be explained in more detail below, a radial stiffness in the braking zone 16 depends on the axial position of the support structure 17 with respect to the withdrawal rim 13.
- an axial position of the support structure 17 in the direction of the drum axis 9 is determined by means of the actuator 25 acting on the support structure 17.
- the support structure 17 comprising the cage 31 and the retaining ring 33 has an essentially frusto-conical shape, wherein the larger end 45 faces towards the winding drum 5.
- the pressing ring 21 is provided at the smaller end 47 of the support structure 17, more particular at the smaller end of the cage 31.
- the actuator 25 is provided with a moveable shaft 27 coupled to pressing ring 21.
- the moveable shaft 27 is arranged coaxial to the thread guide 11 and has a central core for a passage of the weft thread 7.
- the actuator 25 can be driven to move the pressing ring 21 towards the winding drum 5, whereby an axial force is exerted on the support structure 17, or away from the winding drum 5 for decreasing a force exerted or for even moving the braking band 15 away from the withdrawal rim 13.
- the support structure 17 in the embodiment shown is further held in the holder 19 by means of the spring assembly 22 having several spring elements 23.
- the holder 19 is mounted to a frame 49 of the weft feeder device 1.
- the spring elements 23 also exert an axial force on the support structure 17.
- the spring elements 23 allow to center the support structure 17.
- an axial mounting position of the holder 19 at the frame 49 can also be adjusted in the direction of the drum axis 9.
- the holder 19 is moveable in the direction of the drum axis 9 by means of a setting unit 60, which setting unit 60 comprises a setting screw 61 to set the axial mounting position of the holder 19.
- the axial mounting position of the holder 19 determines the axial force exerted by the spring elements 23 on the support structure 17.
- the holder 19 is omitted.
- a cardan suspension 50, 52 is arranged between the pressing ring 21 and the cage 31 of the support structure 17.
- the thread braking device 3 shown in Figs. 1 and 2 further comprises an interface 63 for selecting a force exerted by the actuator 25.
- the interface 63 is designed easy to use.
- N preselected positions and/or N preselected profiles of positions and/or N preselected force values and/or N preselected profiles of force values are stored in the thread braking device in an ascending to descending order and the operator selects a number between 0 and N for having a higher or lower radial stiffness without having to know the position or force associated with the selected number.
- a profile of positions and/or a profile of force values for example can be determined in function of the angular position of the main axis of the weaving machine.
- the interface 63 comprises a turnable knob 62 for selecting the radial stiffness between a level 0 and a level N, with 0 being the lowest level of radial stiffness and N being the highest level of radial stiffness.
- the interface 63 further comprises a display 64 to show the selected level.
- the actuator 25 has a flexibly suspended rotor 26 in order to eliminate parasitic and non-predictable forces due to friction.
- the rotor 26 is suspended by two spring devices 28 allowing the rotor 26 to move in axial direction, but not in a direction perpendicular to the axial direction.
- the rotor 26 is made in one piece with the moveable shaft 27 of the actuator 25.
- a housing 29 is provided, so that the actuator 25 is sealed dust-free.
- the spring devices 28 allow that the cage 31 together with the rotor 26 can move freely in the axial direction, and can be retained in position in a direction perpendicular to the axial direction. By the spring devices 28, the rotor 26 can also move in the axial direction without friction.
- the spring device 28 for example comprises an outer profile 30 to be attached to the housing 29 and an inner profile 32 that suspends the shaft 27, wherein the outer profile 30 is connected to the inner profile 32 by several blade springs 36 in order to allow an axial movement of the shaft 27, but to prevent a movement perpendicular to the axial direction.
- Fig. 3 shows the actuator 25 in an explosive view.
- the actuator 25 comprises a coil 51, a ring 53, a main support 55, a support 57, a permanent magnet 59, a screw-nut 54, positioning parts 56, fixation parts 58 and several elements for assembling the actuator 25.
- the thread braking device 3 without the actuator 25 is shown in detail in Figs. 5 to 8 .
- the support structure 17 has an essentially frusto-conical shape and extends beyond the braking band 15, wherein a larger end 45 of the support structure 17 is designed as an annular weft thread guiding element controlling an entrance of the weft thread 7 into the braking zone 16 and influencing or limiting the formation of a weft thread balloon.
- the support structure 17 comprises the cage 31 and the retaining element 33 that is mounted on an outer support ring 18 of the cage 31. The retaining element 33 is arranged at the larger end 45 of the support structure 17.
- the spring elements 23 are connected to the smaller end 47 of the support structure 17, more particular to the smaller end of the cage 31.
- the cage 31 has an essentially frusto-conical shape and comprises a plurality of arms 34 separated from one another in the circumferential direction by interspaces.
- Fig. 8 shows partially in a sectional view a detail of the thread braking device of Figs. 5 to 7 .
- the braking band 15 is mounted to the retaining element 33 of the support structure 17.
- the retaining element 33 is mounted to the cage 31.
- the retaining element 33 is inserted in the cage 31.
- the retaining element 33 is glued to the outer support ring 18 of the cage 31.
- the retaining element 33 is floatingly supported by the cage 31.
- the cage 31 and the retaining element 33 are made of different material, but formed integrally for example using two-component injection molding.
- the retaining element 33 is made of an elastically deformable material, such as polyurethane.
- the cage 31 is made of a material and designed to have a high axial stiffness. When exerting an axial force to the support structure 17 while the braking band 15 contacts the withdrawal rim 13 (see Fig. 1 ), the retaining element 33 is deformed.
- the retaining element 33 shaped as a retaining ring has a double-curved cross-section for forming two annular portions 35, 37 of different diameter, which are coaxially arranged and, hence, arranged at a distance of one another in the radial direction.
- the portion 35 having the larger diameter abuts against the cage 31.
- the braking band 15 is held by the portion 37 having the smaller diameter.
- the portion 37 of the retaining element 33 having a smaller diameter is provided for receiving the braking band 15, wherein a rear side of the braking band 15 contacts the portion 37 of the retaining element 33 having a smaller diameter.
- the braking band 15 can be glued to the retaining element 33.
- a stiffening element 41 surrounding the braking band 15 at a rear side of the braking band 15 opposite to the braking surface 14 of the braking band 15 is provided.
- the stiffening element 41 is formed by a contour of the cage 31 and forms a circumferential stiffening element 41.
- the braking band 15 is arranged at a distance of the stiffening element 41.
- the retaining element 33 of the support structure 17 is deformed so that the braking band 15 at its rear side via the annual portion 37 of the retaining element 33 is supported by the stiffening element 41. Thereby, a radial stiffness in the braking zone 16 is increased.
- the portion 37 of the retaining element 33 having a smaller diameter is arranged between the braking band 15 and the stiffening element 41 when the braking band 15 is supported by the stiffening element 41 and contacts the stiffening element 41.
- the retaining element 33 can have a collar 24 to guide a weft thread to the braking zone 16.
- Fig. 9 shows a detail of the thread braking device 3 in a somewhat deformed state, wherein the radial stiffness in the braking zone 16 is solely determined by the radial stiffness of the braking band 15.
- Fig. 10 shows a detail of the thread braking device 3 in a more deformed state, wherein the braking band 15 is supported by the stiffening element 41 and the radial stiffness is primarily defined by the stiffening element 41.
- both the radial stiffness, also named contact stiffness, and the axial stiffness, also named macroscopic stiffness, are increased, in particular the stiffness of the braking band 15 is increased at the height of the location where the weft thread 7 is braked by the braking band 15.
- the axial stiffness of the thread braking device 3 is non-linear.
- Fig. 11 schematically shows a curve of a force F exerted in the braking zone 16 as a function of the axial position X of the pressing ring 21.
- a low force F is exerted, wherein a necessary displacement ⁇ x of the pressing ring 21 for increasing the force ⁇ F is rather high.
- the retaining element 33 is deformed so that the braking band 15 is supported by the stiffening element 41, wherein in the embodiment shown, the braking band 15 contacts the stiffening element 41 via the portion 37 of the retaining element 33.
- a necessary displacement ⁇ x of the pressing ring 21 for further increasing the force ⁇ F is comparatively low.
- Fig. 12 shows a detail of an alternative embodiment of a support structure 17 with a cage 31 and a retaining element 33, wherein two stiffening elements 41, 43 are formed at a contour of the cage 31.
- the braking band 15 is fixed to the annual portion 37 of the retaining element 33.
- the retaining element 33 for the braking band 15 will first be supported by the first stiffening element 41, in particular the retaining element 33 retaining the braking band 15 will first contact the first stiffening element 41.
- the retaining element 33 for the braking band 15 Upon a further deformation, the retaining element 33 for the braking band 15 will additionally be supported by the second stiffening element 43, in particular the retaining element 33 will contact the second stiffening element 43. It will be understood by the person skilled in the art that the number, the position and the shape of the stiffening elements 41, 43 is only by way of example and various modifications are possible. In the embodiment shown, the retaining element 33 is not provided with a collar 24 (see Fig. 8 ).
- a retaining element 33 can be provided with a hook shaped retaining slot for receiving the braking band 15, wherein the braking band 15 similar as known from EP 0 963 335 B1 is floatingly retained in the retaining slot.
- the hook shaped retaining slot can also be shaped similar as the collar 24 shown in Fig. 4 .
- the braking band 15 is made in one piece with the retaining element 33, and hence the braking band 15 is mounted directly to the outer support ring 18 of the cage 31.
- the braking band 15 that is supported by the support structure 17 can make direct contact with stiffening elements 41, 43 when the braking band 15 is deformed, in other words the braking band 15 can abut directly against stiffening elements 41, 43.
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Description
- The invention relates to a thread braking device for a weft feeder device with a withdrawal rim, wherein the thread braking device comprises a braking band which cooperates with the withdrawal rim of the weft feeder device to form a weft thread braking zone. The invention also relates to a weft feeder device comprising a thread braking device.
- As generally known, the braking band of a thread braking device for a weft feeder device cooperates with a braking surface at a withdrawal rim of the thread braking device for forming a braking zone. Depending on the shape of the withdrawal rim and the braking band, in use the braking band contacts the withdrawal rim along a circular line or along a circular band-shaped zone. In the context of the application, the extent to which the thread braking device in the braking zone resists deformation in a radial direction of the weft feeder device in response to a force exerted by a weft thread arranged between the braking band and the withdrawal rim is referred to as radial stiffness.
- A thread braking device having a radially deformable braking band with the shape of a frusto-cone is shown in
EP 0 534 263 B1 . Said braking band is supported by a frusto-conical shaped support structure which is radially deformable but axially stiff. The support structure is held by a holder using a spring assembly in a position such that the braking band is forced against the withdrawal rim by the restoration force of the spring assembly.EP 0 867 390 A2 shows a thread braking device, wherein an axial movement of a braking body away from the withdrawal rim is limited using a retention ring made of elastomeric material. The braking body is held in a support via springs. The retention ring is mounted to a threaded ring, which engages with the support. A position of the threaded ring together with the retention ring can be adjusted using a knob. - A thread braking device is further shown for example in
EP 0 963 335 B1 , wherein the thread braking device comprises a braking band floatingly supported by a support structure. According to one embodiment shown inEP 0 963 335 B1 , the braking band is arranged inside the support structure, wherein an elastic element is arranged between the braking band and the support structure. Hence, a radial stiffness in the braking zone is determined by the radial stiffness of the braking band and the elastic element. The elastic element can be exchanged for changing the radial stiffness of the thread braking device, for example for a use of the device with different types of weft threads. - It is the object of the invention to provide a thread braking device with a self-adjustable radial stiffness. It is a further object of the invention to provide a weft feeder device with such a thread braking device.
- This object is solved by the thread braking device with the features of claim 1 and the weft feeder device with the features of
claim 15. Advantageous embodiments are defined in the dependent claims. - According to a first aspect of the invention, a thread braking device for a weft feeder device with a withdrawal rim is provided, the thread braking device comprising a annular braking band with a frusto-conical shape and a braking surface adapted for contacting the withdrawal rim of the weft feeder device for forming a braking zone for a weft thread withdrawn from the weft feeder device, and a support structure, wherein the braking band is supported by the support structure, wherein the support structure is at least partly elastically deformable by an axial force exerted on the support structure, wherein the support structure is provided with at least one stiffening element surrounding the braking band at a rear side of the braking band opposite to the braking surface, in particular a circumferential stiffening element, and wherein in a non-deformed state of the support structure the braking band is arranged at a distance of the stiffening element and by exerting an axial force on the support structure, the support structure is deformable so that the braking band at the rear side of the braking band is supported by the stiffening element.
- The support structure comprises a retaining element for retaining the braking band. The retaining element consists of a retaining ring made of an elastically deformable material, in particular a plastic material, more particular polyurethane. Hence, by exerting a force to the support structure, the retaining element is deformed, thereby causing a movement of the braking band towards the stiffening element until the braking band is supported by the stiffening element. In the context of the application, with "is supported by" is not only meant that the braking band directly abuts against the stiffening element, but the braking band can also indirectly abut against the stiffening element via the retaining element that is arranged between the braking band and the stiffening element.
- In accordance with the invention, the radial stiffness is dependent on the deformation of the support structure, more in particular dependent on the fact whether or not the braking band is supported by the stiffening element, in other words dependent on the fact that the braking band is or is not supported by the stiffening element.
- The braking band is made for example of stainless steel or a plastic material, in particular a fiber-reinforced plastic material. The thickness of the braking band is also chosen by the person skilled in the art and is for example between about 0,004 mm and about 1 mm. Depending on the material chosen, other braking bands having a higher or lower thickness may also be used.
- When the braking band is arranged at a distance of the stiffening element, the radial stiffness in the braking zone is determined by the radial stiffness of the braking band. When the braking band at its rear side is supported by the stiffening element, the radial stiffness in the braking zone is also determined by the radial stiffness of the stiffening element.
- In other words, the radial stiffness of the thread braking device is adjustable. Therefore, the thread braking device is suitable for a large number of different types of weft thread. When weaving thin or weak threads, the thread braking device can be set to have a low radial stiffness. On the other hand, for strong or heavy threads, the thread braking device can be set to have a high radial stiffness. In this way, a uniform low force can be exerted over the entire circumference of the braking zone for weak threads and it is still possible to transfer sufficient force on the thread for strong threads. Here the radial stiffness is determined amongst others by the axial position of the support structure, more in particular by the fact that whether or not the braking band is supported by the stiffening element.
- A stiffening element having a circumferential contour is also referred to as a circumferential stiffening element. In preferred embodiments, the at least one stiffening element has a continuous circumferential contour, and is also referred to as a continuous circumferential stiffening element. The continuous circumferential contour is advantageous for a uniform radial stiffness along the entire braking zone. In an alternative embodiment the stiffening element has a discontinuous circumferential contour, wherein the circumferential contour is formed by a number of stiffening parts arranged at regular short distance from one another, that form together the stiffening element.
- According to an embodiment, the support structure comprises a cage with a frusto-conical shape, wherein the braking band is arranged inside the cage. In the context of the application, the term cage is used for any frusto-conical shaped body enclosing the braking band. In preferred embodiments, the cage may be provided with a plurality of bars or any other type of open framework to avoid dust accumulation in the cage.
- The cage having a frusto-conical shape is arranged with its smaller end facing away from the withdrawal rim. In preferred embodiments, the larger end of the cage extends beyond the braking band, wherein the larger end of the cage functions as a thread guiding element for guiding the weft thread towards the braking zone.
- In one embodiment, the stiffening element and the cage are formed separately and the stiffening element is attached to the cage, for example glued to the cage or clamped in a clamping structure of the cage. In preferred embodiments, the at least one stiffening element is formed integrally with the cage, in particular the at least one stiffening element is formed by a contour of the cage. The cage is for example made of a plastic material, wherein the at least one stiffening element is formed with the cage without requiring any additional assembly step. In one embodiment, several stiffening elements are provided, wherein depending on the deformation, the braking band is supported by at least one selected one of the stiffening elements.
- For a uniform force application to the support structure, in one embodiment, several pressing elements are provided, which are evenly distributed about the circumference of the support structure. In preferred embodiments, the force is exerted centrally. For this purpose, in one embodiment a pressing ring is provided at a smaller end of the cage for exerting an axial force on the support structure.
- The retaining element and the cage together form the support structure. The retaining element and the cage are formed separately. This allows using different materials with different properties for the cage and the retaining element. In one embodiment, the braking band is glued to the retaining element. In other embodiments, the braking band is inserted in a retaining slot provided in the retaining element. In one embodiment, the braking band is floatingly retained in the retaining slot, so that the braking band can position itself with respect to the withdrawal rim. The retaining element, i.e. the retaining ring in one embodiment extends beyond the rear side of the braking band opposite the braking surface, wherein when the braking band is supported by the stiffening element, the portion of the retaining element provided at the rear side of the braking band is arranged between the braking band and the stiffening element. In this case, the radial stiffness in the braking zone is also influenced by the radial stiffness of the retaining element, wherein preferably the radial stiffness of the retaining element is comparatively low and only neglectably influences the overall radial stiffness in the braking zone when the braking band is arranged at a distance of the stiffening element as well as when the braking band is supported by the stiffening element. The cage is made of a suitable material and designed such that the cage has a high axial stiffness and is not or only neglectably deformed by the axial forces exerted.
- The force in one embodiment is exerted by a spring assembly, wherein for example the force and the degree of deformation are settable by choosing an axial position of the support structure with respect to the withdrawal rim. In preferred embodiments, an actuator is provided for exerting an axial force on the support structure. The actuator is arranged at an end of the support structure opposite to the end facing the withdrawal rim. Hence, by means of the actuator, the support structure is displaceable towards the withdrawal rim. Due to the contact of the braking band with the withdrawal rim, the support structure is deformed in response to the force exerted by the actuator. The actuator allows for an automated adaption of the radial stiffness.
- In case only a low force is exerted by the actuator, the braking band is forced against the withdrawal rim without any or with only a neglectable deformation of the support structure, in particular of the retaining element of the support structure. Hence, the braking band is not supported by the stiffening element and the radial stiffness of the braking zone is low. In case a force exceeding a defined threshold is exerted, the support structure, in particular the retaining element of the support structure is deformed and the braking band is supported by the stiffening element or one of a plurality of stiffening elements resulting in an increased radial stiffness. In other words, the thread braking device has a variable radial stiffness as function of the axial position of the support structure with respect to the withdrawal rim.
- The actuator is force-controlled or position controlled, in particular the actuator is force-feed-back controlled or position-feed-back controlled. For a position-feed-back control in one embodiment a sensor is provided for determining the position of the support structure.
- In preferred embodiments, the actuator is a magnetic coil actuator, which is force-controlled so that no further sensor device is required. In preferred embodiments, the actuator comprises a rotor suspended by spring devices, that allow that the rotor moves in an axial direction, but not in a direction perpendicular to the axial direction.
- The thread braking device in one embodiment comprises an interface for selecting a force exerted by the actuator. The interface in preferred embodiments is designed easy to use. For example, N preselected positions and/or N preselected profiles of positions and/or N preselected force values and/or N preselected profiles of force values are stored in the thread braking device in an ascending to descending order and the operator selects a number between 0 and N for having a higher or lower radial stiffness without having to know the position or force associated with the selected number. The interface comprises for example a turnable knob for selecting the radial stiffness between a level 0 and a level N, with 0 being the lowest level of radial stiffness and N being the highest level of radial stiffness. The interface in one embodiment also comprises a display to show the selected level. A profile of positions and/or profile of force values for example can be determined in function of the angular position of the main axis of the weaving machine. The profiles can be chosen such that the force values are relatively high when a weft thread is taken up and/or released by a gripper, and are relatively low when the weft thread does not move or is moved with an almost constant velocity by a gripper.
- In one embodiment, the actuator is further operable to move the braking band away from the withdrawal rim. Hence, by means of the actuator it is also possible to move the braking band away from the withdrawal rim for example for inserting a weft thread after a thread breakage or when changing a braking band.
- In one embodiment, the support structure is exclusively supported by the actuator, for example mounted with its rear end to the actuator. In other embodiments, the thread braking device further comprises a holder, wherein the support structure is moveably in the axial direction held by the holder. By means of the holder, a stability of the system is increased. The holder also allows to counter the gravity force and to improve the central arrangement of the thread braking device with respect to the winding drum.
- In one embodiment, the support structure is held by the holder using a spring assembly. The restoration force of the spring assembly in one embodiment also contributes to the deformation of the support structure. In other embodiments, the spring assembly is designed not to or to only neglectably influence the deformation of the support structure.
- According to a second aspect, a weft feeder device comprising a winding drum with a withdrawal rim and a thread braking device arranged in front of the withdrawal rim is provided, wherein the thread braking device comprises a annular braking band with a frusto-conical shape and a braking surface adapted for contacting the withdrawal rim for forming a braking zone for a weft thread withdrawn from the weft feeder device, and a support structure, wherein the braking band is supported by the support structure, wherein the support structure is at least partly elastically deformable by an axial force exerted on the support structure, wherein the support structure is provided with at least one stiffening element surrounding the braking band at a rear side of the braking band opposite to the braking surface, in particular a circumferential stiffening element, and wherein in a non-deformed state of the support structure the braking band is arranged at distance of the stiffening element and by exerting an axial force on the support structure, the support structure is deformable so that the braking band at its rear side is supported by the stiffening element.
- 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 with a thread braking device according to a first embodiment of the invention,
- Fig. 2:
- shows a detail of
Fig. 1 partially as a sectional view, - Fig. 3:
- shows an explosive view of an actuator of the thread braking device of
Fig. 2 , - Fig. 4:
- shows a detail of the actuator of
Fig. 3 , - Fig. 5:
- shows the thread braking device of
Fig. 1 from the rear side, - Fig. 6:
- shows the thread braking device of
Fig. 1 from the front side, - Fig. 7:
- shows an explosive view of a part of the thread braking device of
Fig. 5 , - Fig. 8:
- shows partially in a sectional view a detail of the thread braking device of
Figs. 5 to 7 , - Fig. 9:
- shows the detail of the thread braking device of
Fig. 8 for exerting a low braking force, - Fig. 10:
- shows the detail of the thread braking device of
Fig. 8 for exerting a high braking force, - Fig. 11:
- shows a curve of a force exerted in the braking zone as a function of the axial position of the pressing ring of the thread braking device of
Figs. 5 to 10 , - Fig. 12:
- shows in a sectional view a detail of the thread braking device according to a second embodiment of the invention.
-
Fig. 1 shows a perspective view of a weft feeder device 1 with athread braking device 3.Fig. 2 shows a detail ofFig. 1 . - The weft feeder device 1 comprises a winding
drum 5 on which a rotating winding arm 6 winds a plurality of turns or windings of aweft thread 7. The rotating winding arm 6 rotates about adrum axis 9. In front of the thread braking device 3 athread guide 11 is arranged. A rounded front end of the windingdrum 5 that extends uninterrupted or continuous over the circumference of the front end of the windingdrum 5, is referred to as withdrawal rim 13. - The
thread braking device 3 shown inFig. 2 comprises acircumferential braking band 15, asupport structure 17 having an annular shape, aholder 19, apressing ring 21, aspring assembly 22 with a plurality ofspring elements 23, and anactuator 25. - As shown in more detail in
Fig. 2 and7 , thesupport structure 17 comprises acage 31 and a retainingelement 33 that is mounted on anouter support ring 18 of thecage 31. The retainingelement 33 retains thebraking band 15. The retainingelement 33 is shaped as a retaining ring, and thecircumferential braking band 15 is shaped as an uninterrupted or continuous circumferential braking band. - As will be understood with reference to
Figs. 1 and2 , theweft thread 7 is withdrawn via thethread guide 11 from the windingdrum 5, wherein during withdrawal theweft thread 7 withdrawn is moving about thewithdrawal rim 13 in abraking zone 16 between thewithdrawal rim 13 and thebraking band 15. - A
braking surface 14 of thebraking band 15 contacts thewithdrawal rim 13 in order to form abraking zone 16 for theweft thread 7 withdrawn from the weft feeder device 1. Thebraking band 15 is made of wear resistant material, e.g. of a metal or a metal alloy, in particular stainless steel, and has the shape of a frusto-conical element. Thebraking band 15 is resiliently deformable in a radial direction of thedrum axis 9, but preferably has a high stiffness in the axial direction. As will be explained in more detail below, a radial stiffness in thebraking zone 16 depends on the axial position of thesupport structure 17 with respect to thewithdrawal rim 13. - In the embodiment shown, an axial position of the
support structure 17 in the direction of thedrum axis 9 is determined by means of theactuator 25 acting on thesupport structure 17. Thesupport structure 17 comprising thecage 31 and the retainingring 33 has an essentially frusto-conical shape, wherein thelarger end 45 faces towards the windingdrum 5. Thepressing ring 21 is provided at thesmaller end 47 of thesupport structure 17, more particular at the smaller end of thecage 31. Theactuator 25 is provided with amoveable shaft 27 coupled to pressingring 21. Themoveable shaft 27 is arranged coaxial to thethread guide 11 and has a central core for a passage of theweft thread 7. Theactuator 25 can be driven to move thepressing ring 21 towards the windingdrum 5, whereby an axial force is exerted on thesupport structure 17, or away from the windingdrum 5 for decreasing a force exerted or for even moving thebraking band 15 away from thewithdrawal rim 13. - The
support structure 17 in the embodiment shown is further held in theholder 19 by means of thespring assembly 22 havingseveral spring elements 23. Theholder 19 is mounted to aframe 49 of the weft feeder device 1. Thespring elements 23 also exert an axial force on thesupport structure 17. Thespring elements 23 allow to center thesupport structure 17. In preferred embodiments, an axial mounting position of theholder 19 at theframe 49 can also be adjusted in the direction of thedrum axis 9. To this end, theholder 19 is moveable in the direction of thedrum axis 9 by means of asetting unit 60, which settingunit 60 comprises a settingscrew 61 to set the axial mounting position of theholder 19. The axial mounting position of theholder 19 determines the axial force exerted by thespring elements 23 on thesupport structure 17. In other embodiments, theholder 19 is omitted. Acardan suspension pressing ring 21 and thecage 31 of thesupport structure 17. - The
thread braking device 3 shown inFigs. 1 and2 further comprises aninterface 63 for selecting a force exerted by theactuator 25. Theinterface 63 is designed easy to use. For example, N preselected positions and/or N preselected profiles of positions and/or N preselected force values and/or N preselected profiles of force values are stored in the thread braking device in an ascending to descending order and the operator selects a number between 0 and N for having a higher or lower radial stiffness without having to know the position or force associated with the selected number. A profile of positions and/or a profile of force values for example can be determined in function of the angular position of the main axis of the weaving machine. The profiles can be chosen such that the force values are relatively high when aweft thread 7 is taken up and/or released by a gripper, and are relatively low when theweft thread 7 does not move or is moved with an almost constant velocity by a gripper. In the embodiment shown, theinterface 63 comprises aturnable knob 62 for selecting the radial stiffness between a level 0 and a level N, with 0 being the lowest level of radial stiffness and N being the highest level of radial stiffness. Theinterface 63 further comprises adisplay 64 to show the selected level. - The
actuator 25 has a flexibly suspendedrotor 26 in order to eliminate parasitic and non-predictable forces due to friction. As best seen inFig. 2 , therotor 26 is suspended by twospring devices 28 allowing therotor 26 to move in axial direction, but not in a direction perpendicular to the axial direction. Therotor 26 is made in one piece with themoveable shaft 27 of theactuator 25. Ahousing 29 is provided, so that theactuator 25 is sealed dust-free. Thespring devices 28 allow that thecage 31 together with therotor 26 can move freely in the axial direction, and can be retained in position in a direction perpendicular to the axial direction. By thespring devices 28, therotor 26 can also move in the axial direction without friction. As shown in more detail inFig. 4 , thespring device 28 for example comprises anouter profile 30 to be attached to thehousing 29 and aninner profile 32 that suspends theshaft 27, wherein theouter profile 30 is connected to theinner profile 32 by several blade springs 36 in order to allow an axial movement of theshaft 27, but to prevent a movement perpendicular to the axial direction. -
Fig. 3 shows theactuator 25 in an explosive view. Theactuator 25 comprises acoil 51, aring 53, amain support 55, asupport 57, apermanent magnet 59, a screw-nut 54,positioning parts 56,fixation parts 58 and several elements for assembling theactuator 25. - The
thread braking device 3 without theactuator 25 is shown in detail inFigs. 5 to 8 . As best seen inFig. 5 , thesupport structure 17 has an essentially frusto-conical shape and extends beyond thebraking band 15, wherein alarger end 45 of thesupport structure 17 is designed as an annular weft thread guiding element controlling an entrance of theweft thread 7 into thebraking zone 16 and influencing or limiting the formation of a weft thread balloon. As best seen inFigs. 6 and8 , thesupport structure 17 comprises thecage 31 and the retainingelement 33 that is mounted on anouter support ring 18 of thecage 31. The retainingelement 33 is arranged at thelarger end 45 of thesupport structure 17. Thespring elements 23 are connected to thesmaller end 47 of thesupport structure 17, more particular to the smaller end of thecage 31. In the embodiment shown, thecage 31 has an essentially frusto-conical shape and comprises a plurality ofarms 34 separated from one another in the circumferential direction by interspaces. -
Fig. 8 shows partially in a sectional view a detail of the thread braking device ofFigs. 5 to 7 . Thebraking band 15 is mounted to the retainingelement 33 of thesupport structure 17. The retainingelement 33 is mounted to thecage 31. The retainingelement 33 is inserted in thecage 31. In one embodiment, the retainingelement 33 is glued to theouter support ring 18 of thecage 31. In other embodiments, the retainingelement 33 is floatingly supported by thecage 31. In still another embodiment, thecage 31 and the retainingelement 33 are made of different material, but formed integrally for example using two-component injection molding. The retainingelement 33 is made of an elastically deformable material, such as polyurethane. Thecage 31 is made of a material and designed to have a high axial stiffness. When exerting an axial force to thesupport structure 17 while thebraking band 15 contacts the withdrawal rim 13 (seeFig. 1 ), the retainingelement 33 is deformed. - In the embodiment shown, the retaining
element 33 shaped as a retaining ring has a double-curved cross-section for forming twoannular portions portion 35 having the larger diameter abuts against thecage 31. Thebraking band 15 is held by theportion 37 having the smaller diameter. In the embodiment shown, theportion 37 of the retainingelement 33 having a smaller diameter is provided for receiving thebraking band 15, wherein a rear side of thebraking band 15 contacts theportion 37 of the retainingelement 33 having a smaller diameter. In this embodiment, thebraking band 15 can be glued to the retainingelement 33. - A stiffening
element 41 surrounding thebraking band 15 at a rear side of thebraking band 15 opposite to thebraking surface 14 of thebraking band 15 is provided. In the embodiment shown, the stiffeningelement 41 is formed by a contour of thecage 31 and forms acircumferential stiffening element 41. - In a non-deformed state of the
support structure 17 shown inFig. 8 thebraking band 15 is arranged at a distance of the stiffeningelement 41. By exerting an axial force on thesupport structure 17, for example by means of theactuator 25, forcing thesupport structure 17 with thebraking band 15 against thewithdrawal rim 13, the retainingelement 33 of thesupport structure 17 is deformed so that thebraking band 15 at its rear side via theannual portion 37 of the retainingelement 33 is supported by the stiffeningelement 41. Thereby, a radial stiffness in thebraking zone 16 is increased. In the embodiment shown, theportion 37 of the retainingelement 33 having a smaller diameter is arranged between thebraking band 15 and thestiffening element 41 when thebraking band 15 is supported by the stiffeningelement 41 and contacts thestiffening element 41. Further, the retainingelement 33 can have acollar 24 to guide a weft thread to thebraking zone 16. -
Fig. 9 shows a detail of thethread braking device 3 in a somewhat deformed state, wherein the radial stiffness in thebraking zone 16 is solely determined by the radial stiffness of thebraking band 15.Fig. 10 shows a detail of thethread braking device 3 in a more deformed state, wherein thebraking band 15 is supported by the stiffeningelement 41 and the radial stiffness is primarily defined by the stiffeningelement 41. - When the
braking band 15 is supported by the stiffeningelement 41, both the radial stiffness, also named contact stiffness, and the axial stiffness, also named macroscopic stiffness, are increased, in particular the stiffness of thebraking band 15 is increased at the height of the location where theweft thread 7 is braked by thebraking band 15. - As a result, the axial stiffness of the
thread braking device 3 is non-linear. -
Fig. 11 schematically shows a curve of a force F exerted in thebraking zone 16 as a function of the axial position X of thepressing ring 21. As will be understood from the drawing, initially a low force F is exerted, wherein a necessary displacement Δx of thepressing ring 21 for increasing the force ΔF is rather high. After reaching a displacement X1, the retaining element 33 (seeFig. 11 ) is deformed so that thebraking band 15 is supported by the stiffeningelement 41, wherein in the embodiment shown, thebraking band 15 contacts thestiffening element 41 via theportion 37 of the retainingelement 33. At the higher forces F exerted a necessary displacement Δx of thepressing ring 21 for further increasing the force ΔF is comparatively low. -
Fig. 12 shows a detail of an alternative embodiment of asupport structure 17 with acage 31 and a retainingelement 33, wherein two stiffeningelements cage 31. Thebraking band 15 is fixed to theannual portion 37 of the retainingelement 33. Depending on the deformation of the retainingelement 33 due to an axial force exerting on thesupport structure 17, the retainingelement 33 for thebraking band 15 will first be supported by thefirst stiffening element 41, in particular the retainingelement 33 retaining thebraking band 15 will first contact thefirst stiffening element 41. Upon a further deformation, the retainingelement 33 for thebraking band 15 will additionally be supported by thesecond stiffening element 43, in particular the retainingelement 33 will contact thesecond stiffening element 43. It will be understood by the person skilled in the art that the number, the position and the shape of thestiffening elements element 33 is not provided with a collar 24 (seeFig. 8 ). - In an alternative embodiment a retaining
element 33 can be provided with a hook shaped retaining slot for receiving thebraking band 15, wherein thebraking band 15 similar as known fromEP 0 963 335 B1 is floatingly retained in the retaining slot. The hook shaped retaining slot can also be shaped similar as thecollar 24 shown inFig. 4 . In another embodiment not shown, thebraking band 15 is made in one piece with the retainingelement 33, and hence thebraking band 15 is mounted directly to theouter support ring 18 of thecage 31. Hereby thebraking band 15 that is supported by thesupport structure 17 can make direct contact with stiffeningelements braking band 15 is deformed, in other words thebraking band 15 can abut directly against stiffeningelements
Claims (15)
- Thread braking device for a weft feeder device (1) provided with a withdrawal rim (13), the thread braking device (3) comprising a annular braking band (15) with a frusto-conical shape and a braking surface (14) adapted for contacting the withdrawal rim (13) of the weft feeder device (1) for forming a braking zone (16) for a weft thread (7) withdrawn from the weft feeder device (1), and a support structure (17), wherein the annular braking band (15) is supported by the support structure (17), and wherein the support structure (17) is at least partly elastically deformable by an axial force exerted on the support structure (17), wherein the support structure (17) is provided with at least one stiffening element (41, 43) surrounding the annular braking band (15) at a rear side of the annular braking band (15) opposite to the braking surface (14), and wherein the support structure (17) comprises a retaining element retaining the annular braking band (15), characterized in that the retaining element (33) consists of a retaining ring made of an elastically deformable material, wherein by exerting a force to the support structure (17), the retaining element (33) is deformed, thereby causing a movement of the annular braking band (15) towards the stiffening element (41, 43) until the annular braking band (15) is supported by the stiffening element (41, 43), wherein in a non-deformed state of the retaining element (33) of the support structure (17) the annular braking band (15) is arranged at a distance of the stiffening element (41, 43) and by exerting an axial force on the support structure (17), the retaining element (33) of the support structure (17) is deformable so that the annular braking band (15) at the rear side of the annular braking band (15) is supported by the stiffening element (41, 43).
- Thread braking device according to claim 1, characterized in that the at least one stiffening element (41, 43) has a continuous circumferential contour.
- Thread braking device according to claim 1 or 2, characterized in that the support structure (17) comprises a cage (31) with a frusto-conical shape, wherein the annular braking band (15) is arranged inside the cage (31).
- Thread braking device according to claim 3, characterized in that the at least one stiffening element (41, 43) is formed by a contour of the cage (31).
- Thread braking device according to claim 3 or 4, characterized in that a pressing ring (21) is provided at a smaller end of the cage (31) for exerting an axial force on the support structure (17).
- Thread braking device according to any one of claims 1 to 5, characterized in that an actuator (25) is provided for exerting an axial force on the support structure (17).
- Thread braking device according to claim 6, characterized in that the actuator (25) is force-controlled or position controlled.
- Thread braking device according to claim 7, characterized in that the actuator (25) is force-feed-back controlled or position-feed-back controlled.
- Thread braking device according to any one of claims 6 to 8, characterized in that the
actuator (25) is a magnetic coil actuator. - Thread braking device according to any one of claims 6 to 9, characterized in that the actuator (25) comprises a rotor (26) suspended by spring devices (28), that allow that the rotor (26) moves in an axial direction, but not in a direction perpendicular to the axial direction.
- Thread braking device according to any one of claims 6 to 10, characterized in that an interface (63) is provided for selecting force values and/or profiles of force values exerted by the actuator (25).
- Thread braking device according to any one of claims 6 to 11, characterized in that the actuator (25) is operable to move the braking band (15) away from the withdrawal rim (13).
- Thread braking device according to any one of claims 1 to 12, characterized in that a holder (19) is provided, wherein the support structure (17) is moveably in the axial direction held by the holder (19).
- Thread braking device according to claim 13, characterized in that the support structure (17) is held by the holder (19) using a spring assembly (22).
- Weft feeder device comprising a winding drum (5) with a withdrawal rim (13), characterized in that a thread braking device (3) according to any one of claims 1 to 14 is arranged in front of the withdrawal rim (13), the thread braking device (3) comprising a annular braking band (15) with a frusto-conical shape and a braking surface (14) adapted for contacting the withdrawal rim (13).
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BE2017/0123A BE1025536B1 (en) | 2017-09-07 | 2017-09-07 | Thread brake device for a weft feed device |
PCT/EP2018/071227 WO2019048158A1 (en) | 2017-09-07 | 2018-08-06 | Thread braking device for a weft feeder device |
Publications (2)
Publication Number | Publication Date |
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EP3679186A1 EP3679186A1 (en) | 2020-07-15 |
EP3679186B1 true EP3679186B1 (en) | 2022-01-05 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP18746720.4A Active EP3679186B1 (en) | 2017-09-07 | 2018-08-06 | Thread braking device for a weft feeder device |
Country Status (4)
Country | Link |
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EP (1) | EP3679186B1 (en) |
CN (1) | CN111051586B (en) |
BE (1) | BE1025536B1 (en) |
WO (1) | WO2019048158A1 (en) |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0963335B1 (en) * | 1997-02-24 | 2001-10-24 | Iro Ab | Thread delivery device and thread brake |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
IT1133900B (en) * | 1980-10-15 | 1986-07-24 | Roy Electrotex Spa | MEANS FOR BRAKING THE OUTPUT YARN IN CONSTANT AND ADJUSTABLE TENSION FEED DEVICES, PARTICULARLY FOR TEXTILE MACHINES |
US5316051A (en) | 1991-09-20 | 1994-05-31 | L.G.L. Electronics S.P.A. | Self-adjusting thread braking device for weft feeder units |
IT1268111B1 (en) * | 1994-10-10 | 1997-02-20 | Lgl Electronics Spa | POSITIVE MODULATED YARN BRAKING DEVICE, FOR WEFT FEEDING DEVICES |
IT1289696B1 (en) * | 1996-11-29 | 1998-10-16 | Lgl Electronics Spa | IMPROVEMENT OF SELF-REGULATING YARN BRAKING DEVICES, FOR WEFT FEEDERS |
WO2007048528A1 (en) * | 2005-10-27 | 2007-05-03 | Memminger-Iro Gmbh | Apparatus for fully-automatized control of the length of a yarn |
EP2058423A1 (en) * | 2007-10-10 | 2009-05-13 | Iro Ab | Weaving machine, yarn feeder and method for inserting a weft yarn |
CN102477653A (en) * | 2010-11-24 | 2012-05-30 | 大连创达技术交易市场有限公司 | Novel yarn braking device |
ITMI20112267A1 (en) * | 2011-12-15 | 2013-06-16 | Btsr Int Spa | SUPPLY DEVICE FOR WIRE TO A TEXTILE MACHINE |
EP2924156B1 (en) * | 2014-03-28 | 2016-11-23 | L.G.L. Electronics S.p.A. | Yarn-braking device for storage yarn feeders |
EP3140446B1 (en) * | 2014-05-09 | 2019-08-28 | Picanol | Weft feeder device |
EP2993260B1 (en) * | 2014-09-05 | 2017-04-19 | L.G.L. Electronics S.p.A. | Yarn feeder with rotary storage drum and yarn-unwinding sensor |
-
2017
- 2017-09-07 BE BE2017/0123A patent/BE1025536B1/en active IP Right Grant
-
2018
- 2018-08-06 EP EP18746720.4A patent/EP3679186B1/en active Active
- 2018-08-06 WO PCT/EP2018/071227 patent/WO2019048158A1/en unknown
- 2018-08-06 CN CN201880058115.2A patent/CN111051586B/en active Active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0963335B1 (en) * | 1997-02-24 | 2001-10-24 | Iro Ab | Thread delivery device and thread brake |
Also Published As
Publication number | Publication date |
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WO2019048158A9 (en) | 2021-09-23 |
WO2019048158A1 (en) | 2019-03-14 |
EP3679186A1 (en) | 2020-07-15 |
BE1025536B1 (en) | 2019-04-08 |
CN111051586A (en) | 2020-04-21 |
BE1025536A1 (en) | 2019-04-02 |
CN111051586B (en) | 2021-05-11 |
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