Weaving method, weft selector for implementing the method and loom comprising the weft selector

Abstract

The method is used to weave a fabric with warp yarns and woven weft yarns (34) on a loom, which includes, among other things, a weft inserter (28) and a weft insertion mechanism (20) for pulling the weft yarn from a pick-up position into a shed along a weft insertion axis (Y20) and in a forward direction, the weft insertion mechanism including a clamp (40) that can be opened in the pick-up position. The method comprises at least the following steps: opening the clamp; positioning the movable support (102) of the weft selector so that the clamp (40) is aligned with the selected weft yarn (34); clamping the weft yarn in the selected distribution channel (130) using the clamp (164) of the selected distribution channel; moving the weft yarn (34) along the selected distribution channel (130) toward the clamp (40) while the clamp is in the open state by moving the clamp along the selected distribution channel; using the clamp to capture the selected weft yarn at a pick-up position; using a weft insertion mechanism to pull the weft yarn from the pick-up position into the shed along the weft insertion axis and in a forward direction; and cutting the weft yarn. The weft selector defines a plurality of selectable distribution channels (130) parallel to the weft insertion axis (Y20), each selectable distribution channel comprising a clamp (164) and a front guide (126) for guiding the weft yarn toward the clamp.

Description

Technical Field

[0001] The invention relates to a method for weaving a fabric on a loom using warp yarns and weft yarns for weaving. The invention also relates to a weft selector allowing the method to be implemented, and to a loom comprising the weft selector.

[0002] The technical field of the invention is the field of weaving of two-dimensional or three-dimensional fabrics, in which different weft yarns, for example different carbon yarns, can be woven due to the use of a multi-weft selector. Background Art

[0003] From EP-A-3121317 it is known to use a method with adjustable weft length for weaving carbon weft yarns of different sizes. This prevents excessive consumption of weft material. In this case, a weft delivery unit is provided. The structure of this weft delivery unit does not allow easy selection of the weft yarn for the next pick.

[0004] On the other hand, US-A-2012 / 0125476 discloses the use of a rotary motion of two rotating arms to insert one of two different weft materials into the shed. This rotary motion is relatively imprecise. The method is limited to two different weft yarns. The ends of the weft material may become loose after cutting and protrude a short length from the rotating unit, resulting in a possibility of being missed by the clamp inserted into the rapier. In addition, each rotating unit in the device needs to be equipped with an electric motor, resulting in the entire device being expensive and bulky. Furthermore, due to the specific clamp shape (which may be more or less concave), the strip is usually bent around its main axis to bring rigidity at its end, which is imprecise and not universal.

[0005] It is also known from DE-A-2531954 to use a weft selector device with a plurality of selectors in order to draw some weft yarns into the shed of a loom. The problem with this weft selector device is that the yarn feeding device is not suitable for moving forward and taking up the weft in the weft direction. In addition, in this known selector, the weft yarns are fed in a direction perpendicular to the weft insertion direction, which is not possible for fragile yarns.

[0006] A multi weft selector suitable for conventional weaving is known from FR-A-2520011. Therein, a vertical fork has two branches which define a flat space in which the different weft yarns extend perpendicularly to the direction of movement of the weft insertion mechanism. The vertical fork moves vertically in order to position one of the weft yarns in front of the weft insertion mechanism. This weft selector cannot be used with relatively hard weft yarns, such as carbon weft yarns. In fact, since the path of the weft insertion mechanism is perpendicular to the weft yarns located between the branches of the vertical fork, relatively strong shearing forces are exerted on the weft material. The device pulls the weft yarns through the shed, which is impossible for carbon weft yarns and other weft yarns that must be well cut and picked up at their free ends (so as not to damage the weft material). Summary of the invention

[0007] The present invention aims to solve the above listed problems by providing a new weaving method which is highly versatile and compatible with many weft yarn materials, in particular with a variety of carbon weft yarns.

[0008] To this end, the invention relates to a method for weaving a fabric with warp yarns and woven weft yarns on a loom, the loom comprising: a heald for moving the warp yarns to form a shed; a shed forming mechanism for moving the heald; a weft bobbin for providing the weft yarn to the loom; a weft insertion mechanism for pulling the weft yarn from a pick-up position into the shed along a weft insertion axis and in a forward direction, the weft insertion mechanism comprising a clamp openable in the pick-up position; and a weft selector defining a plurality of selectable distribution channels parallel to the weft insertion axis, each selectable distribution channel comprising a clamp and a front guide for guiding the weft yarn towards the clamp. The method comprises at least the following steps:

[0009] a) Open the clamp;

[0010] b) positioning the movable support of the weft selector in such a way that the selected distribution channel is aligned on the weft insertion axis so that the clamp is aligned with the selected weft yarn;

[0011] c) clamping the weft thread in said selected distributing channel using the clamp of the selected distributing channel;

[0012] d) moving the weft yarn along the selected dispensing channel toward the clamp by moving the clamp along the selected dispensing channel while the clamp is in the open state;

[0013] e) using a clamp to capture the selected weft yarn at a pick-up position;

[0014] f) pulling the weft yarn from the pick-up position into the shed along a weft insertion axis and in a forward direction using a weft insertion mechanism; and

[0015] g) Cutting the weft yarn.

[0016] In the sense of the present invention, the warp yarns can be of any known type with a circular, oval or rectangular cross section, or with a rectangular cross section with rounded edges, and can be made of any material, in particular yarns made of relatively hard materials such as carbon, glass, ceramic, aramid or Kevlar. When the warp yarns have a rectangular cross section or a quasi-oval cross section, they can also be referred to as ribbons, strips or tapes.

[0017] Thanks to the invention, it is possible to use the selectable distribution channels of the weft selector to feed different weft threads to the weft insertion mechanism, which weft threads are aligned on the weft insertion axis when being fed, without the need to bend these weft threads. In fact, since the selected distribution channel is aligned with the weft insertion axis, the weft thread can enter the shed straight from said distribution channel. In addition, clamping the weft thread and moving it along the selected distribution channel facilitates the capture of the free end of the weft thread by the clamp of the weft insertion mechanism.

[0018] According to an advantageous optional aspect of the invention, considering any technically possible configuration, this method may combine one or more of the following features:

[0019] In step f), the clamping of the weft thread is released.

[0020] After step g), the method comprises the following steps:

[0021] h) moving the weft yarn backwards along the weft yarn insertion axis in the selected distribution channel in a direction away from the clamp, preferably, the backward movement stroke is less than the distance the weft yarn protrudes from the front guide toward the clamp along the weft yarn insertion axis before the backward movement begins.

[0022] In step h), the weft thread is guided by the front guide.

[0023] In step h), the weft thread is clamped by the clamps of the selected dispensing channel.

[0024] In step f), the weft threads of the selected distribution channel are braked.

[0025] In step g), the weft yarns of the selected distribution channel are cut at a predetermined length, and after step g) the method comprises the following steps:

[0026] i) Pull the cut weft yarn forward into the shed at a predetermined position.

[0027] Prior to step b), the method comprises the following steps:

[0028] j) vertically lifting the weft insertion mechanism and the weft selector or keeping them in a vertical position so as to adjust the vertical position of the weft insertion shaft and the vertical position of the selected distribution channel.

[0029] After step e) and before step g), the method comprises the following steps:

[0030] j) moving the clamp backwards in the selected dispensing channel along the weft thread insertion axis in a direction away from the clamp.

[0031] After step d) and before step e), the method comprises the following steps:

[0032] d1) opening the clamp;

[0033] d2) moving the clamp backward along the selected dispensing channel;

[0034] d3) clamping the weft yarn using a clamp;

[0035] d4) moving the weft thread further along the selected dispensing path into the clamp than in step d) by moving the clamp along the selected dispensing path while the clamp is open in the pick-up position.

[0036] According to another aspect, the present invention also relates to a weft selector for delivering weft yarn to a weft yarn insertion mechanism, wherein the weft yarn insertion mechanism is used to pull the weft yarn from a pick-up position into a shed of a loom in a forward direction along a weft yarn insertion axis, wherein the weft yarn insertion mechanism comprises a clamp that can be opened at the pick-up position and movable along the weft yarn insertion axis, and the weft selector comprises a movable bracket. The movable support defines two planes offset from each other along the weft insertion axis, namely a front plane and a rear plane, the front guide is located in the front plane, and the rear guide is located in the rear plane. In addition, the movable support defines a plurality of distribution channels parallel to the weft insertion axis, each distribution channel extending between the front guide and the rear guide, the movable support is configured to align the selected distribution channel on the weft insertion axis, each distribution channel is configured with a clamp, the clamp is configured to hold the weft yarn in the distribution channel and the clamp is movable in a forward direction and a rearward direction between a feeding position in which the weft yarn is extended to the picking position and a retracted position in which the weft yarn is offset from the picking position along the weft insertion axis, a drive assembly for moving the clamp of the selected distribution channel along the weft insertion axis.

[0037] The described weft selector provides substantially the same advantages as the above method. In particular, different weft materials can be provided to the weft insertion mechanism while being aligned with a rapier or another type of weft insertion device, so that the weft is neither damaged nor twisted but is fixed during the transfer between the weft selector and the weft insertion mechanism.

[0038] According to other advantageous but optional aspects of the invention, such a weft selector may combine one or more of the following features, taking into account any technically permissible combination:

[0039] The movable support is movable along an axis perpendicular to the weft thread insertion axis.

[0040] Between its yarn feeding position and its retracted position, the clamp has a stroke less than or equal to 12 mm, preferably less than or equal to 10 mm, more preferably less than or equal to 5 mm.

[0041] The weft selector comprises a single clamp drive configured to selectively exert an opening force on a clamp of a dispensing channel aligned with the weft insertion axis.

[0042] Each distribution channel is configured with,

[0043] a weft feeder supporting the clamp, and

[0044] an elastic return device configured to push the weft feeder back toward the retracted position of the clamp,

[0045] And wherein the weft selector comprises a single drive assembly for moving the weft feeder of any distribution channel aligned with the weft insertion axis along the weft insertion axis.

[0046] The weft selector includes a basket at the pick-up position, the basket being configured to guide the clamp.

[0047] The weft selector includes three drive components, namely:

[0048] a first drive assembly, for positioning the movable support;

[0049] a second drive assembly for opening the clamp so as to align the dispensing channel with the weft insertion axis when the clamp is in the yarn feeding position;

[0050] A third drive assembly is used to move the clamp of the distribution channel aligned with the weft insertion axis along the weft insertion axis toward the feeding position.

[0051] According to a third aspect, the present invention also relates to a loom, comprising: a heald for moving warp yarns to form a shed; a shed forming mechanism for moving the heald; a weft yarn winding drum for providing weft yarns to the loom; a weft yarn insertion mechanism for pulling the weft yarns from a picking position into the shed along a weft yarn insertion direction, the weft yarn insertion mechanism comprising a clamp that can be opened at the picking position; and the weft selector is the weft selector mentioned above.

[0052] This loom offers the same advantages as the method and weft selector of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The invention will be better understood and further advantages thereof will appear more clearly on reading the following description of embodiments of a weaving method, a weft selector and a loom according to the invention, which description is provided by way of example only and is made with reference to the accompanying drawings, in which:

[0054] Figure 1 is a schematic perspective view of a loom according to the present invention;

[0055] Figure 2 yes Figure 1 an enlarged view of detail II, in which the harness is omitted for simplicity;

[0056] Figure 3 According to the present invention, Figure 1 and 2 Enlarged perspective views of some parts of the weft selector of a loom in two different states of construction;

[0057] Figure 4 When the weft selector and the loom are in the first working configuration, Figure 3 A top perspective view of some of the components and a portion of the rapier of the loom is shown,

[0058] Figure 5 is along Figure 4 A partial cross-sectional view of a plane P5 on FIG.

[0059] Figure 6 When the weft selector and the loom are in the second working configuration, similar to Figure 4 A perspective top view of

[0060] Figure 7 is along Figure 6 A partial cross-sectional view of a plane P7 on FIG.

[0061] Figure 8 When the weft selector and the loom are in the third working configuration, similar to Figure 7 A cross-sectional view of

[0062] Fig. 9 When the weft selector and the loom are in the fourth working configuration, similar to Figure 7 A cross-sectional view of

[0063] Fig.10 When the weft selector and the loom are in the fifth working configuration, similar to Figure 7 A cross-sectional view of

[0064] Fig.11 is a perspective view of some components of the weft selector of the present invention taken from another angle;

[0065] Fig.12 is a perspective view of a cutting tool and a weft feeder of a weft selector belonging to the present invention;

[0066] Fig.13 It is used to adjust Figure 1 A perspective view of the drive assembly of some parts of the loom at an elevation;

[0067] Fig.14 Belongs to Figure 1 Perspective view of a loom's reed and associated drives. DETAILED DESCRIPTION

[0068] Figure 1 The loom 2 shown comprises a frame 4 supporting a jacquard device 6 and some control cabinets 8 above a weaving device 10 fixed to a ground G. The frame 4 has a plurality of pillars 12 fixed to the ground, which together support a platform 14 on which the jacquard device 6 and the control cabinet 8 are located.

[0069] The harness 16 made of heddles 17 and cords (not shown) is vertically movable to form a shed (not shown) at the level of the weaving apparatus 10 together with the warp threads 18 coming from a creel (not shown).

[0070] Figure 1 The double arrows A1 in denoted the alternating vertical movement of the bundles of cords and heddles 17 .

[0071] The weft yarn 34 is inserted into the shed using the rapier 20 to weave the fabric 22. Figure 1 and Figure 2 , double arrow A2 indicates the alternating horizontal movement of the rapier 20 along the weft insertion axis Y20 when it is guided by the track 201 of the rapier unit 200, which forms the weft insertion mechanism and also includes a drive, not shown, for moving the rapier 20 reciprocatingly along the weft insertion axis Y20.

[0072] Arrow A3 indicates the unidirectional displacement of the woven fabric 22 toward the take-up stand 24 .

[0073] The reed 23 is used to beat the weft yarn 34 into the fabric 22 after each shuttle pick. Figure 2 and Fig.14 The double arrow A23 in FIG. 1 represents the beating motion of the reed.

[0074] The weft yarn 34 is unwound from a bobbin 26 located beside the weaving machine 10 and is fed from the bobbin to a weft selector 28 via a compensator 30, which is known per se and designed to avoid vibrations when supplying the weft yarn, and from which it is fed to the rapier 20. The compensator 30 ensures that the tension of the weft yarn 34 leaving the compensator is substantially constant.

[0075] In the embodiment of the figures, six bobbins 26 are mounted on a support frame 32 fixed to the ground G, next to the weft selector 28 and the compensator 30. The weft selector 28 can be fed with weft yarns from up to twelve bobbins 26. The number of bobbins 26 can be increased to match the number of different weft yarns to be used in the loom 2.

[0076] In this embodiment, the warp yarns 18 are made of polyester, polyamide or other relatively cheap thermoplastic material. Alternatively, these warp yarns can be made of glass, carbon or another finer material to produce a three-dimensional technical multi-layer fabric, such as for propeller blades, or a two-dimensional multi-layer fabric, such as for technical parts of a car.

[0077] The weft yarns 34 are made of reinforced plastic or of fibers such as carbon, Kevlar, ceramic, aramid or glass. As mentioned above, these yarns can have a circular, oval, rectangular cross section or a substantially rectangular cross section with rounded edges. They can be formed into round yarns, strips, bands or ribbons with a width between 0.014 mm and 5 mm.

[0078] The weft selector 28 comprises a vertically movable support 102 movable along a longitudinal axis Z28 relative to the ground G. The weft selector 28 can be moved by an electric drive assembly 103, which comprises a motor 104, a belt 106 and pulleys not shown incorporated in an upper reversing box 108 and a lower reversing box 108. Two guide rails 110 extend vertically between the two reversing boxes 108, and the two guide rails 110 also belong to the electric drive assembly 103. The electric drive assembly 103 is controlled by an electronic control unit (ECU) 82 contained in one of the control cabinets 8. The ECU comprises at least one microprocessor and a memory, as well as a program for controlling the weft selector 28.

[0079] The vertically movable support 102 includes an upper crossbeam 112 and a lower crossbeam 114, which are adapted to slide along the guide rail 110 when pulled upward or downward by the belt 106. The vertically movable support 102 also includes a front support 116 and a rear support 118. The concepts of "front" and / or "rear" refer to the direction of movement of the rapier 20 when the rapier 20 moves from a pick-up position along the weft insertion axis Y20 into the shed formed by the warp yarns 18. The rapier 20 moves along the weft insertion axis Y20 to the shed formed by the warp yarns 18. Figures 1 to 10 The upper part moves forward from right to left along axis Y20. This is why support 116 is located in front of support 118 along axis Y20.

[0080] The front support 116 is provided with a front eyelet 126 aligned along an axis Z116 parallel to the axis Z28. Similarly, the rear support 118 is provided with a rear eyelet 128 aligned along an axis Z118 parallel to the axis Z28.

[0081] The median plane P116 of the front bracket 116 is defined between its front surface and rear surface and is located at an equal distance from the two surfaces. The median plane P118 of the rear bracket 118 is defined between its front surface and rear surface and is located at an equal distance from the two surfaces. The two median planes P116 and P118 are parallel to each other and form the front plane and the rear plane of the movable bracket 102 respectively. The front plane and the rear plane are perpendicular to the axis Y20 and offset from each other along the axis. The front eyelet 126 and the rear eyelet 128 are located in the front plane P116 and the rear plane P118 respectively. In other words, the front eyelet 126 and the rear eyelet 128 pass through the median plane P116 and the median plane P118 respectively.

[0082] Each front eyelet 126 is aligned with a rear eyelet 128 in the direction of a longitudinal axis Y130 parallel to the axis Y20. A front eyelet 126 and a rear eyelet 128 aligned with the front eyelet along the axis Y130 together define a cylindrical volume 130 called a "distribution channel" extending along the longitudinal axis Y130 between the front support 116 and the rear support 118. Each distribution channel is parallel to the axis Y20. Optionally, each distribution channel is approximately parallel to the axis Y20. The longitudinal axis Y130 of each distribution channel 130 is tangential to the lower part of the two eyes 126 and 128 defining the distribution channel. Therefore, the weft yarn 34 placed in the lower part of the two eyes 126 and 128 of the distribution channel 130 extends along its longitudinal axis Y130.

[0083] The distribution channel 130 is composed of, for example, Figure 4 The gray area on the

[0084] The weft thread 34 can slide along each distributing channel 130 in the direction of its longitudinal axis Y130 in order to be captured in a pick-up position by a clamp 40 of a rapier 20 situated outside this distributing channel 130 , as explained below.

[0085] Said front eyelet 126 and said rear eyelet 128 are made of rings mounted in holes formed on the front support 116 and the rear support 118, these supports having a thickness of about 5 mm measured in a direction parallel to the axis Y20, while the eyelets have a diameter of about 3 mm and rounded edges. Thus, these eyelets provide a smooth guiding surface for the weft yarn 34 sliding along the distribution channel 130 defined between the two aligned eyelets 126 and 128.

[0086] Alternatively, the eyelets 126 and 128 are made of holes drilled directly through the brackets 116 and 118, which holes also have rounded edges in order to provide a smooth guiding surface for the weft yarn 34 as well.

[0087] In the embodiment of the figures, all the eyelets 126 and 128 are identical. This is not mandatory, and the size and shape of the eyelets can be adjusted along the height of the support 116 or 118, respectively, to adapt to the size and cross-section of the weft yarn 34 moving through the distribution channel 130.

[0088] In this embodiment, each front support 116 or rear support 118 is provided with 12 front eyelets 126 or rear eyelets 128, thereby defining 12 distribution channels 130 between these supports; these distribution channels are arranged one above the other in the direction of the axis Z28. Thus, 12 different weft yarns 34 from 12 different bobbins 26 can be processed in the weft selector 28.

[0089] The number of holes per bracket is unlimited, and thus the number of distribution channels 130 is also unlimited, as long as the number is at least equal to 2. Preferably, the number of distribution channels 130 is at least 3, more preferably at least 5, and even more preferably at least 12.

[0090] 140 represents the frame of the weft selector 28, which is only partially shown for the sake of simplicity and clarity. Figure 3 The left side and Figure 4 The box 108 and the guide rail 110 are stationary relative to the frame 140.

[0091] Due to the drive assembly 103, the support 102 can be moved upward or downward along the axis Z28 relative to the frame 140 and the ground G, such as Figure 3 As shown by the double arrow A4 in FIG.

[0092] This allows aligning the selected distribution channel 130, corresponding to the next weft thread to be woven during the next pick-up, with the weft insertion axis Y20. More precisely, the longitudinal axis Y130 of the selected distribution channel 130 can be aligned with the axis Y20 by means of a vertical movement of the support 102. This vertical upward or downward movement of the support 102 is made relative to the frame 140 and by comparing Figure 3 The two configuration states of the weft selector 28 shown can be understood. In this specification, when the longitudinal axis Y130 of the distribution channel 130 is aligned with the weft insertion axis Y20, the distribution channel 130 is said to be aligned with the weft insertion axis Y20. Figure 3 In the left construction state, the uppermost distribution channel 130 of the bracket 102 is aligned with the axis Y20, and in the right construction state, the 5th distribution channel 130 starting from the top of the bracket 102 is aligned with the axis Y20.

[0093] The motion stroke of the support 102 is limited by the drive assembly 103. The motion stroke corresponds to the motion stroke of the support 102 in Figure 3 The movement between the position shown on the left and the position in which the lowest distributing channel 130 is aligned with the weft insertion axis Y20. For a support 102 comprising 12 distributing channels 130 of the embodiment of the figures, this travel is approximately 140 mm.

[0094] The basket 150 is supported by the frame 140 of the multiple weft selector 28 and is adapted to receive the head 202 of the rapier 20 with the clamp 40 .

[0095] The clamp 40 has two clamping jaws 42 .

[0096] The basket 150 has two guide surfaces for positioning the head 202 of the rapier longitudinally and vertically relative to the weft selector 28. More precisely, the basket comprises a lower horizontal surface 152 parallel to the axis Y20 and an upper inclined surface 154 inclined towards the axis Y20 in a direction towards the weft selector 28. The basket 150 is suitable for positioning the head 202 of the rapier longitudinally and vertically relative to the weft selector 28. Figure 5 The direction of the arrow A5 guides the head 202 of the rapier along the axis Y20, i.e. towards a pick-up position for picking up a weft thread close to the front support 116. This allows the clamp 40 to be positioned accurately relative to the front eyelet 126 of the dispensing channel aligned with the axis Y20, as shown in FIG. Figure 5 shown.

[0097] According to an alternative embodiment of the invention not shown, and if the rapier 20 is hard enough to reach Figure 4 and Figure 5 If the pick-up position shown is used, the basket 150 can be omitted. Alternatively, the basket can be replaced by any other alternative, for example, a guide device equipped with a groove, ramp, kinematic link or crank for positioning the rapier.

[0098] Each distribution channel 130 is equipped with a weft feeder 160 that is slidably movable along an axis Y130 and guided by two rails 132 and 134 parallel to this axis. The weft feeder 160 is not completely enclosed in the volume of the corresponding distribution channel 130 between the support 116 and the support 118, but is located partly in this channel and partly outside of it. For the sake of clarity, the two rails are only shown in FIG. Figure 5 and Figures 7 to 10 The two tracks are shown in Fig.11 Two housings 1626 and 1628 are provided in the body 162 of each weft feeder 160 for receiving a portion of the rails 132 and 134 respectively and with a small radial play to allow the body 162 to slide along the two rails 132 and 134.

[0099] For simplicity, in Figure 4 and Figure 6 Only one weft feeder 160 is shown. Figure 3 As shown, twelve weft feeders 160 may be mounted on the bracket 102 .

[0100] Each weft feeder 160 is movable along the distribution channel 130 between the front bracket 116 and the rear bracket 118. More specifically, each weft feeder 160 can be moved along the rails 132 and 134. Figure 4 and 5 The weft feeder 160 is shown in a rearward or retracted position adjacent to the rear support 118 and as shown in FIG. Figures 6 to 10 The weft feeder 160 is shown sliding between the forward positions close to the front bracket 116. The forward position of the weft feeder 160 is also a feeding position, because, in this position, the weft feeder 160 can feed the weft yarn 34 into the clamp 40.

[0101] The displacement of each weft feeder 160 between the front support 116 and the rear support 118 along the distribution channel 130 to which it is engaged occurs along the longitudinal axis Y130 of this distribution channel 130 and along the weft insertion axis Y20. This displacement is obtained by a motor 170 that drives a connecting rod 172 in translation along an axis Y172 parallel to the axes Y20, Y130, Y132 and Y134 through a crank mechanism 174. The motor 170 is fixedly mounted on the frame 140 and is controlled by the ECU 82. The motor 170, the connecting rod 172 and the crank mechanism 174 together form an electric drive assembly 173, which is used to move the selected weft feeder 160 towards the front support 116.

[0102] A spring 176 is inserted between the weft feeder 160 and the front bracket 116 .

[0103] Under the action of the force F6 exerted by the connecting rod 172 driven by the crank mechanism 174, the weft feeder 160 moves along the Figure 5 The direction of arrow A6 occurs from Figure 5 Position to Figure 7 The force F6 is a thrust applied to the back side 1622 of the body 162 of the weft feeder 160. For the movement of the weft feeder 160 in the direction of the arrow A6, the forward movement of the weft feeder 160 is smoother than that obtained using a pneumatic drive, due to the use of an electric drive assembly 173 comprising an electric motor 170, a crank mechanism 174 and a connecting rod 172 resting against the body 162. Therefore, the pulling force applied by the relevant weft feeder 160 on the weft yarn 34 to unwind it from its bobbin 26 is smoother.

[0104] Under the action of the elastic force F6' exerted by the spring 176 on the front side 1624 of the main body 162 toward the rear bracket 118, the weft feeder 160 moves along Figure 5 The direction of arrow A6' occurs from Figure 7 Position to Figure 5 Therefore, the spring 176 constitutes an elastic reset device, which is configured to move the weft feeder 160 toward Figure 4 and Figure 5 Push back to the retracted position shown.

[0105] The weft feeder 160 further comprises a clamp 164 formed by a fixed clamp jaw 1642 and a movable clamp jaw 1644. The fixed clamp jaw 1642 is stationary relative to the body 162. The movable clamp jaw 1644 is hinged to the body about an axis (not shown) perpendicular to the axes Y132 and Y134.

[0106] Since each clamp 164 belongs to a weft feeder 160, the clamp 164 and the main body 162 of the weft feeder are arranged along the longitudinal axis Y130 of the distribution channel 130. Figure 4 and 5 The rearward or retracted position shown corresponds to Figures 6 to 10 It is movable between the shown advance position or the yarn feeding position.

[0107] The spring 166 is mounted on the body 162 of each weft feeder 160 and pushes the movable claw 1644 toward the fixed claw 1642 in a default state, in which the clamp 164 clamps a portion of the weft yarn 34 fixed relative to the weft feeder 160. In other words, in a default state, the weft yarn 34 is clamped by the clamp 164, as shown in FIG. Fig.11 As shown by arrow A11.

[0108] The fixed jaw 1642 has a U-shaped recess configured to receive a projection 1643 of a movable jaw 1644. The geometry of the two jaws 1642 and 1644, and in particular of the projection 1643, is chosen to limit the risk of damaging a weft thread 34 clamped by the clamp 164. The U-shape of the fixed jaw 1642 is particularly suitable for guiding different types of weft threads and for fixing the weft thread 34 relative to the body 164, thereby preventing the weft thread from slipping out of the clamp 164 when loose yarns or wavy yarns are used as weft threads.

[0109] In the embodiment of the figures, all clamps 164 and all springs 166 and 176 are identical for all weft feeders 160. However, in an alternative embodiment not shown, the clamps 164 and springs 166 and 176 can be customized for each weft feeder 160 so as to be perfectly adapted to the geometry and type of material of the weft yarn 34 passing through the corresponding distribution channel 130.

[0110] An electric motor 180 is provided for controlling the opening movement of each clamp 164 against the elastic force applied by the corresponding spring 166. The electric motor 180 is rigidly mounted on the frame 140 and controlled by the ECU 82. When the weft feeder has moved to its front position, the electric motor 180 is located beside the basket 150 and positioned in a manner capable of interacting with the clamp 164 of the weft feeder 160 of a single distribution channel 130 aligned with the weft insertion axis Y120. In other words, when any weft feeder 160 is located in the distribution channel 130 aligned with the rapier 20, especially aligned with the clamp 40 of the rapier, and when the weft feeder is in its yarn feeding position, the single electric motor 180 matched by the ECU 82 is used to selectively open the clamp 164 of the weft feeder 160.

[0111] The motor 180 drives the roller 182 via the eccentric 184. The components 180, 182 and 184 together form an electric drive 183 for operating the clamp 164 of the weft feeder in its front position or feeding position. The roller 182 is designed to selectively lift the movable claw 1644 relative to the fixed claw 1642 by a distance of about 3 mm.

[0112] When the electric drive 183 does not act on the clamp 164, the clamp 164 is closed relative to the horizontal plane under the effect of the elastic force exerted by the spring 166, so that the clamped weft thread 34 remains substantially straight in the corresponding distribution channel 130. In other words, it is not necessary to bend the weft thread 34 passing through the distribution channel 130 in order to clamp it.

[0113] Because of the positioning of the electric drive 180 relative to the frame 140, the weft feeder can be moved forward only when it has been pushed forward by the motor 170 to the position where the weft feeder 180 is located. Figure 6-10The roller 182 interacts with the clamp 164 of the weft feeder 160 only when the weft feeder is in the pre-position or feeding position shown. In other words, the motor 180 can open the clamp 164 of the weft feeder 160 only when the weft feeder is located in the distribution channel 130 aligned on the axis Y20 and only when the weft feeder has been previously pushed forward to the feeding position by the electric drive assembly 173.

[0114] The vertically oriented optical sensor 190 is only Figure 5 As can be seen from the top and with a viewing direction indicated by arrow A190, the optical sensor 190 is mounted in the lower part of the weft selector 28, below the movable support 102 and supported by the frame 140. The sensor 190 allows to determine whether at least one weft feeder is in its forward position or feeding position, or whether all weft feeders 160 are in their rearward position or retracted position. The sensor 190 can also check the opening state of the clamp 164 when the clamp belongs to a weft feeder that is in its forward position or feeding position. Alternatively, another sensor, not shown, can be used to check the state of the clamp 164.

[0115] The output signal of the sensor 190 is taken into account by the ECU 82 to actuate the electric actuators 103, 173 and 183. In particular, the electric actuator 103 cannot be actuated if one of the clamps is in its forward position. Not to mention that the electric actuator 103 cannot be actuated if the clamps are open.

[0116] The cutting tool 210 is mounted beside the basket 150 and comprises an upper blade 212 and a lower blade 214. The upper blade is stationary relative to a body 222 of a cutting unit 220, which comprises a first linear pneumatic drive 224 for moving the cutting unit 220 along a horizontal axis X220 perpendicular to the axis Y20, and a second pneumatic drive 226 for moving the lower blade 214 relative to the upper blade 212 when it is necessary to cut the weft yarn 34. Fluid connectors 2262 and 2264 connect the pneumatic drive 226 to an air tube not shown.

[0117] In this embodiment, a single cutting unit 220, ie a single cutting tool 210, is used to selectively cut a weft thread 34 passing through any dispensing channel 130 of the movable support aligned on the weft thread insertion axis Y20.

[0118] ECU 82 also controls an air source at a pressure not shown to provide air to pneumatic drivers 224 and 226 .

[0119] Only in Fig.12The optical sensor 230 shown above and with the viewing direction extending in the direction of the arrow A230 allows detecting the position of the blades 212 and 214 relative to each other, in particular when the blades cross, ie when cutting the weft yarn 34. Its output signal is also supplied to the ECU 82.

[0120] In the field of three-dimensional weaving, the insertion of overlapping weft yarns is a problem, especially when using a double rapier system. Since the final fabric is relatively thick in such a system, the jacquard system opens different successive sheds at different heights relative to the frame of the loom 10 (i.e. at different heights relative to the ground G). On the other hand, in order to optimize the weaving process, it is best to keep the shed height relatively small.

[0121] In order to facilitate inserting the weft yarn into different sheds at different heights, the loom 2 of the present invention includes a lifting system 300, which includes a first lifting device 310 for vertically moving the rapier unit 200, and a second lifting device 320 for lifting the weft selector 28.

[0122] exist Fig.13 , only the lifting system 300 is schematically shown, the guide rail 201 represents the rapier unit 200, and the frame 140 represents the weft selector 28.

[0123] The first lifting unit 310 includes a stationary frame 312 fixed to the ground G and a movable frame 314 for supporting the rapier unit. The servo drive 316 drives three worm gears through three angular gear boxes 318. This allows the three ball screw spindles 319 to be moved vertically and simultaneously. Therefore, the vertical rise of the movable frame 314 can be controlled while keeping the movable frame 314 parallel to the ground G.

[0124] On the other hand, the second lifting device 320 includes a stationary frame 322 fixed to the ground G and a movable frame 324 for supporting the frame 140 of the weft selector 28. The servo driver 326 drives the gear box 328 and the ball screw spindle 329 to move the movable frame 324 vertically.

[0125] The two lifting devices 310 and 320, and in particular their respective servo drives 316 and 326, are electronically controlled by the ECU 82 in order to obtain at all times the same displacement of the two movable frames 314 and 324 in terms of direction, speed and acceleration. One servo drive may be a master drive and the other a slave drive.

[0126] By simultaneously moving the weft insertion device 200 vertically as indicated by the double arrow A200 and the weft selector 28 vertically as indicated by the double arrow A28, it is possible to always keep the weft selector 28 horizontally aligned with the weft insertion device 200 when the weft is successively inserted into the sheds stacked one above the other. Thanks to the system 300, the vertical positions of the weft insertion device 200 and the weft selector 28 can be adjusted, and thus the vertical positions of the weft insertion axis Y20 and the selected distribution channel 130 relative to the ground G and the weaving device 10, in particular relative to the woven fabric 22, can be adjusted. The lifting of the weft insertion device 200 and the lifting of the weft selector can overlap in time with the position adjustment of the movable support 102, thereby reducing downtime.

[0127] Alternatively, the two lifting devices may be mechanically coupled via a common shaft. In this case, a single drive, such as a servo drive 316, may be used. The common shaft may be considered and described below. Fig.14 The axes of the servo drives of the reeds shown in FIG. 1 are coaxial with each other.

[0128] It is known from the prior art to use a reed, also called a sley, which is articulated on the main shaft of the weaving machine via a mechanical cam connection. The reed beats each weft thread into the fabric to stabilize its position. The movement of the reed depends on the cam profile and cannot be adjusted without changing the mechanical cam connection, which is complicated. The movement of the reed is essentially a circular movement, which is disadvantageous for certain weft materials, especially weft materials including carbon structures.

[0129] In the loom 2 of the present invention, the alternating movement of the reed 23 is indicated by the double arrow A23, which is obtained by an independent drive mechanism 400, which includes an electric motor 412, a set of connecting rods 414, a crank mechanism 416 and a subframe 418 hinged to the main shaft 420 by two brackets 422. The flywheel 444 also belongs to the drive mechanism 400.

[0130] The drive mechanism 400 allows the continuous rotation of the motion of the motor 412 to be converted into Figure 2 and Fig.14 The arrow A23 on the top indicates the horizontal alternating motion. The structure of the drive mechanism 400 allows a portion of the reed 23 to be suspended, because only one side of the reed is connected to the drive mechanism 400.

[0131] Due to the motion conversion obtained by the drive mechanism 400, the motion of the reed 23 is mainly horizontal, which is advantageous for weaving and beating up a multi-layer fabric 22 of considerable thickness. The results obtained are better than with a rotating reed, where the part that is beaten up the most is the uppermost layer of the fabric.

[0132] Since the motor 412 is an electric motor, its working conditions can be controlled by the ECU 82 and easily customized. The direction of rotation of the motor 412 can be quickly reversed. The stroke, speed and acceleration of the reed movement can be adjusted, so that the duration and acceleration of the reed movement can be easily adjusted. Since the reed 23 is servo-driven, its movement is independent of the movement law of the jacquard machine 6 and the cutting and weft insertion process. The acceleration, speed, position and amplitude of the movement of the reed 23 can be easily adapted to the weaving process, the material of the yarn and the actual structure of the woven fabric 22.

[0133] In particular, on the basis of the torque generated by the motor 412, the force exerted by the reed 23 on the fabric can also be measured or determined by calculation. This allows the stroke of the reed to be adjusted according to the fabric being woven, the material of the yarn and the speed of the weaving process, etc. In particular, the measurement of the torque and its interpretation by the ECU 82 of the loom 2 make it possible to know the yarn tension, which can be monitored and adjusted by means not shown.

[0134] The following describes how to use Figures 1 to 14 The weaving method implemented by the loom shown.

[0135] If necessary, the system 300 can be used to lift the weft insertion mechanism 200 and the weft selector 28 to adapt to the actual height of the shed and the position of the weft relative to the ground G. This lifting can be done at the beginning of weaving of a new fabric or during weaving, especially between two weft insertion cycles.

[0136] Whenever the rapier head 202 returns to the yarn feeding position, the clamp of the rapier head is opened by a known, not shown, mechanism, thereby forming a closable volume for accommodating the weft yarn end. Optionally, the rapier head 202 can be opened before the yarn feeding position is reached along the weft yarn insertion axis.

[0137] The sensor 190 is used to monitor the position of all weft feeders 160 in their respective distribution channels 130 in order to check that no weft feeder 160 and no clamp 164 are in their front position or feeding position. This allows avoiding collisions between the weft thread 34 and the movable support 102 during the vertical displacement of the movable support 102.

[0138] Depending on the next weft yarn for weft insertion at the next pick, referred to as the "selected yarn", one of the distribution channels 130 is selected by the ECU 82. The selected distribution channel is the channel where the selected yarn is located.

[0139] Then, ECU 82 controls drive assembly 103 to vertically move or hold movable support 102 so as to align selected distribution channel 103 on weft insertion axis Y20. In other words, selected weft 34 is aligned with fixture. This can occur during shed opening. If the selected yarn is different from the yarn used for the previous shuttle, it means that vertical movement of movable support 102 is required. If the selected weft is the same as the yarn used for the previous shuttle, movable support 102 does not move, and previously selected distribution channel 130 remains aligned with the weft insertion axis. Rapier head is opened before positioning movable support 102 of weft selector 28. Optionally, the opening of rapier head can overlap with the positioning of movable support 102 in time, so that fixture 40 is aligned with selected weft 34.

[0140] Then, the motor 170 is actuated so as to apply a thrust F6 through the connecting rod 172 to push the weft selector 160 located in the selected distribution channel 130 forward, that is, toward the front bracket 116. By default, since the clamp 164 is Fig.11 As shown by the arrow A11 in FIG. 1 , the weft feeder 160 is closed by means of a spring 166, so that this forward movement of the weft feeder 160 indicated by the arrow A6 causes a similar forward movement of the weft yarn 34, which is clamped by the clamp 164 and pulled out from the corresponding bobbin 26. Here, the clamp 164 of the weft feeder 160 in the selected distribution channel 130 is moved from its retracted position to its forward position by the electric drive assembly 173 operated by the ECU 82. Figure 7 As shown, during the forward movement of the clamp 164 and the weft yarn 34 clamped therein, the clamp 40 remains in the open state.

[0141] This allows the weft feeder 160 and the clamp 164 to reach the position against the elastic force F6' applied by the spring 176. Figure 6 and Figure 7 In this position, if Figure 7 As shown, the weft yarn 34 is clamped by the clamp 164 and its free end 342 projects from the support 102 by a distance d measured parallel to the axis Y20. Said distance d is large enough to allow the free end 342 to extend between the jaws 42 of the clamp 40.

[0142] Therefore, in Figure 6 and Figure 7 In the forward position, the clamp 164 holds the weft yarn 34 in a position that allows the clamp 40 to be fed.

[0143] Then, if Figure 8 As shown by arrow A8 in FIG. 4 , the clamp 40 can be closed by moving the clamping jaws 42 toward each other by an actuating device (not shown).

[0144] Then, if Fig. 9 As shown in the arrow A9 in the figure, the clamp 164 is opened by the effect of the electric drive assembly 183 as described above. This releases the clamping of the selected weft yarn 34 and disconnects the weft yarn from the weft feeder 160.

[0145] Then, if Fig.10 As shown, the rapier 20 leaves the basket 150 in the forward direction indicated by the arrow A10 and pulls the weft yarn 34 into the shed. During the movement of the rapier through the shed, the weft yarn 34 is unwound from its bobbin. If necessary, a braking force can be applied by the clamp 164 to keep the weft yarn in tension. To this end, the electric drive assembly 183 can be actuated by the ECU 82 to move the movable jaw 1644 towards the fixed jaw 1642 under the action of the elastic force applied by the spring 166 so as to apply a controlled braking force.

[0146] The position at which the weft yarn is cut is set by the position of the cutting tool 210 along the weft yarn insertion axis Y20. Here, one can use the teaching of EP-A-3121317 to weave weft yarns of different lengths in the fabric 22. However, this is not necessary. In this case, the weft yarn 34 is cut at a predetermined length and then the cut weft yarn 34 is pulled into the shed at a predetermined position along the forward direction A10.

[0147] When the rapier head 202 has reached the set position for entering the shed, the motor 180 is actuated by the ECU 82 again to close the clamp 164 under the effect of the spring 166. Then, the weft yarn is clamped again to wait for being cut and will not be lost after being cut.

[0148] exist Fig.10 After the step shown and after clamping the weft thread, the first pneumatic drive 224 is actuated to move the cutting unit 220 along the axis X220 towards the thread 34 extending through the basket 150 .

[0149] Then, the second pneumatic drive 226 is actuated to move the lower blade 214 to cut the weft yarn 34. The sensor 230 can be used to control the cutting of the weft yarn before the next step. Then, the cutting tool is opened again by the drive 226 and moved back to its original position by the drive 224.

[0150] Then, the electric drive assembly 173 is actuated to move the rod 172 backward, which allows the spring 176 to push the weft feeder 160 to its retracted position in the direction of the arrow A6' toward the rear bracket 118 via the elastic force F6'. During this backward movement, the clamp 164 clamps the weft yarn 34 because it has been closed by the previous action of the motor 180, and the front eyelet 126 guides the weft yarn 34.

[0151] Optionally, the clamp 164 can be closed by moving away from its forward position and away from the position of contact with the roller 182. Optionally, the clamp can start moving backward just before cutting the weft yarn, so as to generate the necessary clamping tension of the weft yarn between the clamp and the gripper, thereby performing an effective cutting operation. After cutting, the clamp ends its backward movement towards its retracted position.

[0152] This returns the weft feeder 160, the clamp 164, and the weft yarn 34 to Figure 4 and 5 the position where the end 342 of the weft yarn still projects from the movable support 102 through the front eyelet 126 at a distance d' less than the distance d, and the clamp 164 still holds the weft yarn 34.

[0153] In fact, between the position of Figure 6-10 and the position of Figure 4 and 5 the stroke S of the backward movement of the weft feeder 160 is equal to the difference between the distances d and d'. The following formula applies:

[0154] S = d - d' (Formula 1)

[0155] The stroke S is selected such that the distance d' is strictly maintained greater than zero. The following formula applies:

[0156] S < d (Equation 2)

[0157] d' > 0 (Formula 3)

[0158] In other words, in the selected distribution channel 130, at the end of the backward movement of the weft feeder 160 and the clamp 164, the end 342 of the weft yarn projects a non-zero distance d' from the front eyelet 126 in the direction towards the weft insertion mechanism 200. Therefore, the weft yarn 34 is guided by the front eyelet 126 of the corresponding distribution channel 130 and is clamped by the clamp 164 during the backward movement of the clamp 164. At the end of the backward movement, the weft yarn does not break away from the front eyelet 126. Therefore, the next time the weft yarn 34 of this distribution channel is to be used for the next shuttle throw, when the clamp 164 will start moving towards its yarn feeding position, the free end 342 has already projected from the movable support 102. In this way, the weft yarn will surely be firmly grasped when the clamp closes.

[0159] The value of the stroke S is selected to be less than or equal to 12 mm, preferably less than or equal to 10 mm, more preferably less than or equal to 5 mm.

[0160] The distance d′ is also chosen to be smaller than the distance d40 measured along the axis Y20 between the clamp 40 and the front support 116 when the rapier head 202 is located in the basket 150. Thus, even if the rapier head 202 is already in its pick-up position, there is no risk that the rapier head 202 will collide with the weft thread end 342 when the support 102 is moved along the axis Z28.

[0161] Advantageously, the distance d is chosen to be greater than 1 cm, preferably equal to 1.2 cm, while the distance d′ is chosen to be greater than 1 mm and less than 5 mm, preferably equal to 2 mm.

[0162] According to a first, not shown, alternative embodiment of the method of the invention, after the clamp 164 has been opened by the action of the electric drive assembly 183, and when the weft yarn 34 is pulled into the shed, the electric drive assembly 173 is actuated so that the clamp 164 moves backwards in the selected distribution channel 130 along the weft insertion axis Y20 by a distance equal to, for example, 2 mm, which is a stroke S1 less than the stroke S equal to, for example, 10 mm. The clamp 164 stops moving and clamps the weft yarn 34 before cutting the weft yarn 34 at a predetermined length. Then, the electric drive assembly 173 is actuated so that the weft feeder 160 is pushed to the retracted position in the direction of the arrow A6' under the action of the elastic force F6' applied by the spring 176, and its stroke S2 ​​is equal to the difference between the stroke S and S1, that is, S2=S-S1, which is 10 mm-2 mm=8 mm in this embodiment. The distance d" measured between the front eyelet 126 and the weft yarn end 342 extending from the movable support 102 is greater than the distance d' defined above, and the following equation therefore applies: d" = d' + 2 mm = d' + S1. The stroke S1 can be seen as a preliminary backward stroke of the weft feeder 160, which moves the weft yarn 342 further out of the weft feeder 160 and into the jaws 42 of the clamp 40, so that the distance d" is increased compared to the distance d' of the embodiment represented in the accompanying drawings. In other words, the weft yarn end 342 extends further than in the embodiment shown in the figures. The stroke S1 facilitates deeper feeding of the clamp, and in particular makes it easier to pick up the weft yarn end 342 and hold it in the jaws 42. This first alternative embodiment avoids the need to change the geometric arrangement or distance between the cutting unit 220 and the weft feeder 160 in order to provide a longer weft yarn end 342 to the clamp 40.

[0163] In a second, not shown, alternative embodiment of the method of the present invention, after the electric drive assembly 173 has moved the weft feeder 160 to its front position with the weft yarn 34 clamped by the clamp 164, the weft yarn 34 can be moved forward for a second time along the weft insertion axis Y20 by operation of the weft selector 28, while the clamp remains open in the picking position.

[0164] This second forward movement of the weft yarn 34 along the weft insertion axis Y20 is performed after the clamp 164 is opened in its front position and after the clamp 164 is moved backward in the selected distribution channel 130. The weft yarn 34 is then clamped in this retracted position using the clamp 164 and the weft yarn 34 is moved along the weft insertion axis Y20 in the selected distribution channel 130 to its front position into the clamp 40 by actuating the electric drive assembly 173 against the elastic force F6' applied by the spring 176, while the clamp remains open in the pick-up position.

[0165] When the clamp 164 holds the weft yarn 34, the second forward movement of the clamp 164 allows the weft yarn end 342 to be moved further out of the weft selector 160 and into the jaws 42 of the clamp 40, so that the distance d' is increased compared to the first movement of the weft feeder 160 to its forward position. The clamp 40 can then be closed to capture the weft yarn 34 with more weft yarn material in the jaws 42. This operation corresponds to a two-step mode of moving the weft yarn 34 into the clamp 40.

[0166] In a third, not shown, alternative embodiment of the method of the present invention, the weft feeder 160 and the clamp 164 through the selected distribution channel 130 can be operated continuously in three steps or more to move the weft yarn 34 further into the clamp 42.

[0167] By means of appropriate driving of the electric drive assembly 173 by the ECU 82, the stroke of each forward movement, the advance position of the weft feeder 160 and the retracted position along the axis Y20 can be adjusted.

[0168] Alternatively, when the weft feeder 160 operates the rearward movement of the clamp 164, the jaws 42 of the clamp 40 may move toward each other and catch the weft yarn 34 so that the weft yarn 34 does not move rearward or get lost.

[0169] Due to the construction of the weft feeder 28 of the present invention, the distribution channel 130 of the weft yarn is parallel to the weft yarn insertion axis Y20, and the clamp 164 has a precisely controlled translational movement, thereby ensuring that the free end 342 of the weft yarn to be introduced into the shed can be effectively picked up by the clamp 40 at the picking position of the rapier 20, wherein the free end 342 of the weft yarn always extends from the front eyelet 126 of the distribution channel 130.

[0170] Once the weft thread has been cut and the corresponding weft feeder 160 has been moved back to its retracted position, the rapier 20 is pulled out of the shed and the reed 23 strikes the woven fabric 22 before a new weft thread insertion cycle begins.

[0171] The present invention has many advantages, including the following:

[0172] The invention allows providing the technical loom 2 with different types of weft yarn material.

[0173] The present invention ensures that the weft material will not be distorted by the weft selector 28 or the weft insertion mechanism 200.

[0174] The construction of the weft selector 28 ensures that the weft material is fed directly to the gripping jaws 42 of the rapier and that no bending of the yarn material is required.

[0175] The present invention allows providing a relatively long weft yarn to the rapier head 202 so that the rapier head 202 grabs the weft yarn 34 regardless of the smoothness or stiffness of the material.

[0176] When the weft material has a rectangular cross-section (eg a ribbon), it is clamped and inserted into the shed along a substantially flat plane.

[0177] The invention also ensures that any type of weft material is located in the correct position in the rapier head 202, regardless of its rigidity.

[0178] Due to the structure of the weft selector 28, the delivery of the weft yarn can be guaranteed even if the weft yarn is not used for a long time, because each clamp 164 remains closed as long as it is not in the selected channel and as long as it is not pushed to the front position.

[0179] The invention also ensures correct positioning of the rapier head 202 relative to the front guide formed by the front eyelet 126 , thanks to the use of the basket 150 .

[0180] The invention allows to use an optimum amount of weft yarn material, since no material is lost when closing the jaws 42 on the free end 342. This saves some yarn material relative to existing solutions.

[0181] The invention also prevents weft thread ends 342 from being hit in a configuration in which the free ends 342 of the respective weft threads 34 protrude from the support 102 by a smaller distance d′ if the clamp 40 is located in the basket 150 and the movable support 102 is moved.

[0182] Due to the braking possibility provided by the clamp 164 and due to the possibility of clamping the weft thread with the clamp if necessary, the invention also allows an optimized transport of the weft thread during weft thread insertion.

[0183] The invention also allows controlled cutting of the weft thread during pick-up.

[0184] Furthermore, the weft selector 28 of the present invention operates rapidly and can work mainly during the hidden process time of the loom 2.

[0185] Compared to other known systems, the weft selector of the present invention is compact.

[0186] In an alternative embodiment of the invention which is not shown, the weft insertion mechanism 200 may use a weft feeder other than a rapier.

[0187] According to an alternative embodiment of the invention, instead of a jacquard machine, another type of shedding machine can be used, such as a dobby machine, a cam machine or an electric actuator to move the heddles and thus control the vertical position of the warp threads.

[0188] According to another alternative embodiment of the invention, the geometrical arrangement of the weft yarn distribution channels 130 may differ from that shown in the drawings. The Z28 axis may be inclined or horizontal.

[0189] The weft selector 28 may be located on the right side of the loom 10, as shown, or on the other side.

[0190] According to another embodiment of the invention, not shown, the two weft feeders 160 can be moved in parallel in order to bring their respective clamps 164 into their respective feeding positions so that the two weft ends 342 can be caught by the clamps 40 of two parallel and superposed rapiers. Solutions with two rapiers moving side by side are also compatible with the invention.

[0191] The drive solution can be modified. The engine can be electric, pneumatic or hydraulic. In particular, the cutting tool 210 can be driven by an electric motor with a crank mechanism, so that the trajectory of the movable blade can be changed, and the blade of the cutting unit can cut the weft yarn at different positions along the blade, so that the blade does not wear at a precise position. This increases the life of the cutting tool 210. The solution of equipping each channel 130 with a clamp drive 183 is compatible with the present invention, but is less economical than the solution of equipping all channels with only a single drive.

[0192] In particular, the first linear pneumatic drive 224 can be replaced by a servo drive for moving the cutting unit 220 along the horizontal axis X220. In this case, the positioning of the lower blade 214 and the upper blade 212 relative to the weft yarn 34 and relative to the axis Y20 is precisely controlled, so that the position of the cutting point of the weft yarn 34 can be adjusted by the ECU 82 according to the weft yarn characteristics, the yarn count, etc. Advantageously, random micro-variations can be used in the positioning of the cutting unit 220 relative to the weft yarn by the servo drive. This allows to change the contact surface of the lower blade 214 and the upper blade 212 for subsequent cutting operations. Therefore, the life of the lower blade 214 and the upper blade 212 can be increased.

[0193] Data exchange can be performed via the ECU 82 or another control unit of the loom 2. The weft feeder 28 can also be controlled by a separate controller. The ECU can be located outside the control cabinet 8 or can be divided into several ECUs located in different cabinets.

[0194] The various steps of the method of the present invention may overlap in time to increase the overall speed of the method.

[0195] As contemplated in EP-A-3121317, the method is particularly suitable for inserting weft yarns of a predetermined length which is less than the full width of the woven fabric 22. However, full width weft yarns are compatible with the present invention.

[0196] The weft selector 28 of the present invention can be used for other kinds of yarns and other weaving techniques except those mentioned above. For example, a similar weft selector can be used to alternately deliver different types of weft yarns to the rapier in a carpet weaving machine.

[0197] The weft yarn end 342 can be bent about its major axis to make the yarn stiffer when passing through the weft selector 28. For example, the clamp 160 can have a rounded shape that deforms the weft yarn end into a semi-tube shape so that the weft yarn end does not tend to bend downward like a flat weft yarn end under its own weight.

[0198] If the weft thread end 342 needs to be guided in a long pipe, the front guide formed by the eyelet 126 and the clamp 164 can be combined in multiples.

[0199] The front guide 126 may be mounted on an elastic system, located on the front side of the movable support 102 and on the trajectory of the rapier 20, so that the rapier 20 can push the front support 116 with a smaller stroke.

[0200] The above-mentioned embodiments and variants can be combined within the framework of the appended claims in order to produce new embodiments of the invention.

Claims

1. A method of weaving a fabric (22) on a loom (2) using warp yarns (18) and weft yarns (34), comprising: a heald (17) for moving the warp yarns to form a shed; A shed forming mechanism (6) for moving the heald; a weft yarn bobbin (26) for providing weft yarn to the loom; A weft insertion mechanism (200) for pulling the weft from a pick-up position into a shed along a weft insertion axis (Y20) and in a forward direction (A10), the weft insertion mechanism comprising a clamp (40) that can be opened at the pick-up position; a weft selector (28) defining a plurality of selectable distribution channels (130) parallel to the weft insertion axis (Y20), each selectable distribution channel comprising a clamp (164) and a front guide (126) for guiding the weft towards said clamp; The method comprises at least the following steps: a) Open the clamp; b) positioning the movable support (102) of the weft selector in such a way that the selected distribution channel (130) is aligned on the weft insertion axis (Y20) so that the clamp (40) is aligned with the selected weft yarn (34); c) clamping (A11) the weft yarn in the selected distributing channel (130) using the clamp (164) of the selected distributing channel; d) moving (A6) the weft yarn (34) along the selected dispensing channel (130) towards the clamp (40) by moving the clamp along the selected dispensing channel while the clamp is in the open state; e) using a clamp to capture the selected weft yarn at a pick-up position; f) pulling the weft yarn from the pick-up position into the shed along a weft insertion axis (Y20) and in a forward direction (A10) using a weft insertion mechanism; and g) Cutting the weft yarn.

2. The method according to claim 1, wherein: In step f), the clamp (164) releases (A9) the grip of the weft thread (34).

3. The method according to claim 1, wherein: After step g), the method comprises the following steps: h) moving (A6') the weft thread (34) backwards along the weft thread insertion axis in the selected distribution channel (130) in a direction away from the clamp (40).

4. The method according to claim 3, wherein: In step h), the stroke (S) of the backward movement of the weft yarn (34) is less than the distance (d), which is the distance that the weft yarn extends from the front guide (126) toward the clamp (40) along the weft yarn insertion axis (Y20) before the backward movement begins.

5. The method according to claim 3, wherein: In step h), the weft yarn (34) is guided by the front guide (126).

6. The method according to claim 3, wherein: In step h), the weft yarn (34) is clamped by the clamp (164) of the selected distribution channel (130).

7. The method according to any one of claims 1 to 6, wherein: In step f), the weft thread (34) of the selected distribution channel (130) is braked.

8. The method according to any one of claims 1 to 6, wherein: In step g), the weft yarns (34) of the selected distribution channel (130) are cut to a predetermined length, and after step g), the method comprises the following steps: i) Pull the cut weft yarn forward into the shed at a predetermined position.

9. The method according to any one of claims 1 to 6, wherein: Prior to step b), the method comprises the following steps: j) vertically lifting (A200, A28) the weft insertion mechanism (200) and the weft selector (28) or keeping them in a vertical position so as to adjust the vertical position of the weft insertion shaft (Y20) and the vertical position of the selected distribution channel (130).

10. The method according to any one of claims 1 to 6, wherein: After step e) and before step g), the method comprises the following steps: j) moving (A6') the clamp (164) backwards along the weft insertion axis (Y20) in the selected distribution channel (130) in a direction away from the clamp (40).

11. The method according to any one of claims 1 to 6, wherein: After step d) and before step e), the method comprises the following steps: d1) opening the clamp (164); d2) moving the clamp (164) rearwardly along the selected dispensing channel (130); d3) clamping the weft yarn (34) using a clamp (164); d4) moving the weft yarn (34) along the selected distribution channel (130) further into the clamp (40) than in step d) by moving the clamp (164) along the selected distribution channel while the clamp is in the open state in the picking position.

12. A weft selector (28) for delivering a weft yarn (34) to a weft insertion mechanism (200), the weft insertion mechanism (200) being used to pull the weft yarn (34) from a pick-up position into a shed of a loom (2) along a weft insertion axis (Y20) in a forward direction (A10), the weft insertion mechanism comprising a clamp (40) which is openable at the pick-up position and movable along the weft insertion axis, wherein The weft selector comprises a movable bracket (102), The movable support defines two planes (P116, P118) offset from each other along the weft insertion axis (Y20), namely a front plane (P116) and a rear plane (P118); A front guide (126) located in the front plane; a rear guide (128) located in the rear plane; The movable support (102) defines a plurality of distribution channels (130) parallel to the weft insertion axis, each distribution channel extending between the front guide and the rear guide; The movable support is configured to align the selected distribution channel (130) on the weft insertion axis (Y20); Each distribution channel is provided with a clamp (164), which is configured to hold a weft yarn (34) in the distribution channel and is movable in a forward direction (A6) and a rearward direction (A6') between a feeding position in which the weft yarn is extended to the pick-up position and a retracted position in which the weft yarn is offset from the pick-up position along the weft insertion axis; and A third drive assembly (173) is used to move the clamp (164) of the selected distribution channel (130) along the weft insertion axis (Y20).

13. The weft selector according to claim 12, wherein: The movable support (102) is movable along an axis (Z28) perpendicular to the weft insertion axis (Y20).

14. The weft selector according to any one of claims 12 and 13, wherein: Between its yarn feeding position and its retracted position, the clamp (164) has a stroke (S) less than or equal to 12 mm.

15. The weft selector according to claim 14, wherein: The clamp (164) has a travel (S) of less than or equal to 10 mm between its yarn feeding position and its retracted position.

16. The weft selector according to claim 15, wherein: The clamp (164) has a travel (S) of less than or equal to 5 mm between its yarn feeding position and its retracted position.

17. The weft selector according to any one of claims 12 and 13, wherein: The weft selector comprises a single clamp drive (183) configured to selectively exert an opening force on a clamp (164) of a distribution channel (130) aligned with the weft insertion axis (Y20).

18. A weft selector according to any one of claims 12 and 13, wherein each distribution channel (130) is provided with a weft feeder (160) supporting the clamp (164), and an elastic return device (176) configured to push the weft feeder back toward the retracted position of the clamp (F6'), And wherein the weft selector (28) includes a single third drive assembly (173) for moving the weft feeder (160) of any distribution channel (130) aligned with the weft insertion axis along the weft insertion axis (Y20).

19. The weft selector according to any one of claims 12 and 13, wherein: The weft selector comprises a basket (150) located at the pick-up position, the basket (150) being configured to guide the clamp (40).

20. The weft selector according to any one of claims 12 and 13, wherein: The weft selector includes three drive components, namely: A first driving assembly (103) for positioning the movable support (102); a second drive assembly (183) for opening the clamp (164) so ​​as to align the dispensing channel (130) with the weft insertion axis when the clamp is in the feeding position; The third driving assembly (173) is used to move the clamp (164) of the distribution channel (130) aligned with the weft insertion axis (Y20) toward the yarn feeding position along the weft insertion axis (Y20).

21. Loom (2), comprising: a heald (17) for moving the warp yarns (18) to form a shed; A shed forming mechanism (6) for moving the heald; a weft yarn bobbin (26) for providing weft yarn (34) to the loom; A weft insertion mechanism (200) for pulling the weft from a pick-up position into a shed in a forward direction (A10), the weft insertion mechanism comprising a clamp (40) that can be opened at the pick-up position; Weft selector (28), It is characterized in that the weft selector (28) is the weft selector according to any one of claims 12-20.

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