Description

The invention relates to a method and a device for inserting weft threads into a shed of a weaving machine by means of a gripper device, wherein at least two weft threads are inserted at the same time. The invention further relates to a weaving machine.

Inserting weft threads using a gripper device is known. Typical gripper devices comprise a feed gripper and a receiving gripper, which receiving gripper takes over the weft threads from the feed gripper.

EP 0 633 336 A1 shows a method and a device for inserting two weft threads at the same time, wherein a first weft thread is permanently threaded onto a feed gripper, and a second weft thread is presented to the feed gripper and taken up by the feed gripper. The weft threads are guided along separate running paths, in order to prevent entangling of the weft threads. Due to the permanently threaded first weft thread, the choice of a weaving pattern to be woven is very limited.

WO 2009/135636 A1 shows a weaving machine with a presenting device for selecting two weft threads from a plurality of weft threads according to a weaving pattern. A gripper device shown in WO 2009/135636 A1 comprises a receiving gripper and a feed gripper. For inserting two weft threads at the same time, the receiving gripper and/or the feed gripper are provided with a thread separator, which thread separators allow two weft threads to be separated from each other while these two weft threads are clamped.

WO 2010/142264 A1 also discloses a gripper weaving machine arranged for inserting two weft threads at the same time, wherein two - - weft threads are selected from a number of weft threads, are presented to a feed gripper, are clamped by the feed gripper, and are inserted into a shed. The two weft threads are guided and clamped in the feed gripper by separate elements, wherein the separate elements are arranged to position the two weft threads in such a way that these two weft threads remain separated during the clamping of the weft threads in the clamping area.

It is the object of the invention to provide a method and a device for inserting weft threads into a shed of a weaving machine by means of a gripper device, wherein at least a first weft thread and a second weft thread are inserted at the same time, and wherein an entangling of the two weft threads is avoided.

This object is solved by the method according to claim 1 , the device according to claim 9 and the weaving machine according to claim 17.

According to a first aspect, a method for inserting weft threads into a shed of a weaving machine by means of a gripper device is provided, wherein at least a first weft thread and a second weft thread are inserted at the same time, the method comprises presenting the first weft thread and the second weft thread to the gripper device, moving the gripper device to take up the first weft thread and the second weft thread and to insert the first weft thread and the second weft thread at the same time into a shed, and after the gripper device has taken up the first weft thread and the second weft thread and before crossing of warp threads, driving an adjustment device, which is provided at a weft thread insertion side of the weaving machine, to move the first weft thread at the weft thread insertion side of the weaving machine transversally to the insertion direction and away from the second weft thread, so that, when the first weft thread and/or the second weft thread are caught by crossing warp threads, the first weft thread and the second weft thread - - are distanced from each other over the inserted length of the first weft thread and the second weft thread.

According to a second aspect, a device for inserting weft threads into a shed of a weaving machine is provided, the device comprises a presenting device and a gripper device, wherein the presenting device is arranged to present the first weft thread and the second weft thread to the gripper device, wherein the gripper device is arranged to take up the first weft thread and the second weft thread and to insert the first weft thread and the second weft thread at the same time into a shed, and wherein the device further comprises an adjustment device provided at a weft thread insertion side of the weaving machine, wherein the adjustment device is arranged to move the first weft thread at the weft thread insertion side of the weaving machine transversally to the insertion direction and away from the second weft thread after the gripper device has taken up the first weft thread and the second weft thread and before crossing of warp threads, so that, when the first weft thread and/or the second weft thread are caught by crossing warp threads, the first weft thread and the second weft thread are distanced from each other over the inserted length of the first weft thread and the second weft thread.

The first and the second weft thread inserted at the same time into the shed are referred to as conjointly inserted weft threads. The section of the weft threads inserted into a shed is referred to as inserted length of the weft threads. For inserting the weft threads into the shed, the inserted weft threads are held by the gripper device. In an embodiment, at least one thread separator is provided at the gripper device for keeping the leading ends of the inserted weft threads at a distance from each other. According to the invention, the first weft thread is moved at the weft thread insertion side of the weaving machine transversally to the insertion direction and away from the second weft thread. - -

Preferably, the leading ends of the inserted weft threads are still held by the gripper device when moving the first weft thread at the weft thread insertion side. Due to the relative movement of the first weft thread away from the second weft thread at the weft thread insertion side, the inserted weft threads are kept at a distance from each other over the entire inserted length of the weft threads, wherein in an embodiment the distance between the inserted weft threads decreases towards the section where the inserted weft threads are held by the gripper device.

Depending on a weaving pattern, all or some of the warp threads forming a shed are moved to cross, wherein the inserted weft threads are caught between the warp threads. At the instant of crossing of warp threads, the gripper device has moved to a position at least substantially outside the shed to avoid an interference with the crossing warp threads. According to the invention, when the weft threads are caught by crossing warp threads, the first weft thread and the second weft thread are distanced from each other over the inserted length of the first weft thread and the second weft thread. At the instant the gripper device has moved to a position at least substantially outside the shed, the inserted length of the weft threads essentially coincides to the width of the fabric. In the context of the application, the width of a fabric is defined as the usable area of the fabric. In case a selvedge fabric is provided which is cut off or otherwise unused and discarded, the "width of the fabric" does not necessarily include the area of the selvedge fabric. In particular, in case selvedge warp threads cross at an instant later than the instant of crossing of warp threads, the gripper device may still be situated between the selvedge warp threads at the instant of crossing of warp threads.

In an embodiment, the weft threads are presented to the gripper device at a distance from each other in the direction of movement of a reed beating up the weft threads. In an embodiment, when the first weft - - thread is moved away from the second weft thread at the weft thread insertion side, the distance between the first weft thread and the second weft thread in the direction of movement of the reed is at least substantially maintained at the weft thread insertion side, wherein the first weft thread is moved transversally to the insertion direction and transversally to the direction of movement of the reed at the weft thread insertion side of the weaving machine. In preferred embodiments, the first weft thread is moved at the weft thread insertion side of the weaving machine transversally to the insertion direction, away from the second weft thread, and towards the fell line or away from the fell line, so that the distance of the first weft thread from the fell line differs from the distance of the second weft thread from the fell line over the entire inserted length of the first weft thread and the second weft thread at the instant warp threads cross, and the weft thread closer to the fell line is caught first by the crossing warp threads.

In preferred embodiments, the adjustment device is arranged and/or driven to move the first weft thread at the weft thread insertion side of the weaving machine transversally to the insertion direction, towards a fell line and away from the second weft thread. For example, the first weft thread is moved at least substantially in the direction of movement of the reed during beat up. In known weaving machines, during beat up, the reed is moved substantially in horizontal direction. Hence, the adjustment device is arranged to move the first weft thread at the weft thread insertion side substantially in horizontal direction. The direction of movement of the first weft thread may deviate from the direction of movement of the reed during beat up within tolerances, wherein the direction of movement is chosen so that an interference with warp threads forming the shed is avoided. Such an interference is negatively effecting the insertion of the weft threads. However, in some embodiments, the warp threads may support a movement of the first weft thread towards the fell line. - -

When moving the first weft thread at the weft thread insertion side towards the fell line, for example at least substantially in the direction of movement of the reed and away from the second weft thread, wherein the inserted weft threads are conjointly held by a gripper device, the inserted weft threads form an angle opening towards the weft thread insertion side. The angle formed by the first weft thread and the second weft thread depends on the relative movement of the first weft thread at the weft thread insertion side. Preferably, an angle of less than 45° is formed between the first weft thread and the second weft thread. Due to the difference in distance between the first weft thread and the second weft thread from the fell line at the instant warp threads cross, the weft thread closer to the fell line is caught first by the crossing warp threads. After the weft threads are caught by the warp threads, a relative movement of the first weft thread and the second weft thread, which may cause a partial crossing of weft threads, is avoided. In preferred embodiments, at the instant the reed comes into contact with one of the weft threads and this weft thread is moved together with the reed towards the second weft thread, at least the weft thread closer to the fell line is already at least partly caught between the crossing warp threads. In result, during beat up the weft threads do not move over each other.

In preferred embodiments, the gripper device comprises a feed gripper and a receiving gripper, wherein the feed gripper takes up the presented weft threads and brings the inserted weft threads into the shed, transfers the inserted weft threads to the receiving gripper, preferably halfway along the shed, and the receiving gripper then brings the inserted weft threads to the weft thread arrival side. In other embodiments, the gripper device comprises only a receiving gripper or only a feed gripper.

In case the gripper device comprises a feed gripper and a receiving gripper, preferably the adjustment device is arranged and/or driven to - - move the first weft thread transversally to the insertion direction and away from the second weft thread after the receiving gripper has taken over the first weft thread and second weft thread from the feed gripper. In case only a receiving gripper or only a feed gripper is provided, the first weft thread is preferably moved at the weft thread insertion side only after the gripper device has moved far enough inside the shed.

In preferred embodiments, the adjustment device is arranged and/or driven to move the first weft thread over an element of the gripper device, so that the first weft thread and the second weft thread extend along both sides of said element of the gripper device between a weft thread holding region of the gripper device and the weft thread insertion side. In case the gripper device comprises a feed gripper and a receiving gripper, preferably the adjustment device is driven to move the first weft thread over the feed gripper, so that the first weft thread and the second weft thread extend along both sides of the feed gripper between the receiving gripper and the weft thread insertion side.

In known devices, weft threads are presented to the gripper device, more particular to the feed gripper, in such way that the gripper device takes up the weft thread between the fell line and a thread supply, wherein the taken up weft threads are moved by the feed gripper into the shed and extend at the side of the feed gripper facing away from the fell line. By means of the adjustment device the first weft thread, that is moved through the shed together with the second weft thread by the receiving gripper, in preferred embodiments is forced to move over the feed gripper to extend at the other side of the feed gripper, this means at the side facing the fell line.

By moving the first weft thread so that the two weft threads extend at both sides of the feed gripper, there is always a distance between the inserted weft threads in the direction of movement of the reed during - - beat up and before crossing, this means in horizontal direction. When the first weft thread is moved by the adjustment device after the receiving gripper has taken over the inserted weft threads, the movement does not interfere with a clamping of the weft threads in the feed gripper. Preferably, the first weft thread is moved by the adjustment device immediately after the receiving gripper has taken over the inserted weft threads and while the receiving gripper is still moving through the shed.

In preferred embodiments, the adjustment device is integrated in the presenting device, wherein in a first period in the weaving cycle the presenting device is driven to present the first weft thread and the second weft thread to the gripper device, and wherein in a second period in the weaving cycle, after the gripper device has taken up the first weft thread and the second weft thread and before crossing of warp threads, the presenting device is driven to move the first weft thread at the weft thread insertion side of the weaving machine transversally to the insertion direction and away from the second weft thread, so that when the first weft thread and/or the second weft thread are caught by crossing warp threads, the first weft thread and the second weft thread are distanced from each other over their inserted length. Thereby, a compact solution is provided, wherein the number of moving elements is kept small.

In an embodiment, the presenting device comprises a plurality of presenting members corresponding to a plurality of weft threads from which a first weft thread and a second weft thread are selected, wherein the plurality of presenting members is portioned in at least a first and a second set of presenting members, each set comprising at least one presenting member, wherein in the first period one presenting member of the first set of presenting members is moved to a presenting position for presenting the first weft thread to the gripper device and one - - presenting member of the second set of presenting members is moved to a presenting position for presenting the second weft thread to the gripper device. In an embodiment, the presenting device comprises two presenting members for presenting two weft threads. In other embodiments, more than two weft threads are prepared for an insertion, wherein for each insertion, a first weft thread and a second weft thread are selected from the plurality of weft threads.

Preferably, in the second period in the weaving cycle the at least one presenting member of the first set of presenting members presenting the first weft thread in the first period in the weaving cycle is driven to move the first weft thread at the weft thread insertion side of the weaving machine transversally to the insertion direction and away from the second weft thread, so that when the first weft thread and/or the second weft thread are caught by crossing warp threads, the first weft thread and the second weft thread are distanced from each other over their inserted length. In an embodiment, presenting needles are provided as presenting members. The presenting members comprise a thread guide, in particular a needle eye, for guiding the associated weft thread. Presenting needles with needle eyes and devices for a substantially translational movement of the needle eyes are disclosed in EP 0 598 264 A1 , the content of which is herewith incorporated by reference. Thereby the movement of the elements is kept simple.

In an embodiment, in the second period in the weaving cycle said presenting member of the first set of presenting members is moved relative to said presenting member of the second set of presenting members in order to move the first weft thread at the weft thread insertion side of the weaving machine transversally to the insertion direction and away from the second weft thread. - -

In preferred embodiments, a guide element for the first weft thread, in particular a presenting member, of the presenting device is at least substantially translationally moved.

In a preferred embodiment, the thread guide of said presenting member of the first set of presenting members is moved in the presenting position and/or out of the presenting position at least substantially in parallel to the direction of movement of a reed during beat up. In another embodiment, the thread guide of said presenting member of the first set of presenting members is moved in a diagonal direction, wherein a displacement of the thread guide of said presenting member in horizontal direction exceeds its displacement in vertical direction. In other words, in contrast to presenting devices shown for example in WO 2009/135636 A1 , the needle eyes of the presenting needles of the first set of presenting needles are moved in a direction that is inclined more towards a horizontal plane. The presenting needles of the second set of presenting needles in an embodiment are arranged in a known manner and the needle eyes of the presenting needles of the second set of presenting needles are moved in a more vertical direction compared to the presenting needles of the first set of presenting needles. In other embodiments, the presenting members are moved at least substantially in the same direction, wherein the movement of the presenting members differs in timing and/or in distance, so that when catching the first weft thread and/or the second weft thread by crossing warp threads, the first weft thread and the second weft thread are distanced from each other over their inserted weft length. For example, in an embodiment, the second weft thread is presented to the gripper device at a position that is further distanced from the fell line in the direction of movement of the reed during beat up than the position in which the first weft thread is presented. After the gripper device has taken up the first weft thread and the second weft thread and before crossing of warp threads, the presenting member presenting the first weft thread is moved out of the - - presenting position and towards the fell line before the presenting member presenting the second weft thread is moved.

According to a third aspect, a weaving machine is provided comprising a control unit arranged for carrying out the described method and/or comprising the described device.

Further features and advantages of the invention will emerge from the following description of the embodiments illustrated in the drawings, in which:

Figure 1 is a perspective view of a device according to the invention comprising a presenting device for the presenting of two weft threads to a feed gripper, and the feed gripper;

Figure 2 is a schematic and simplified top view of the device in

Figure 1 when presenting the weft threads;

Figure 3 is a schematic and simplified side view of the device in

Figure 1 when presenting the weft threads;

Figure 4 is a schematic and simplified top view of the device in

Figure 1 when taking up the weft threads;

Figure 5 is a schematic and simplified side view of the device in

Figure 1 when taking up the weft threads;

Figure 6 is a schematic and simplified top view of the device in

Figure 1 when taking over the weft threads;

Figure 7 is a schematic and simplified top view of the device in

Figure 1 after taking over the weft threads;

Figure 8 is a top view of a receiving gripper used in the device according to the invention;

Figure 9 is a schematic and simplified top view of the device in

Figure 1 when further inserting the weft threads;

Figure 10 is a schematic and simplified side view of the device in

Figure 1 when further inserting the weft threads; - -

Figure 1 1 is a schematic and simplified top view of the device in

Figure 1 at the end of inserting the weft threads;

Figure 12 is a schematic and simplified side view of the device in

Figure 1 at the end of inserting the weft threads;

Figure 13 is a schematic and simplified top view of the device in

Figure 1 after beating up the weft threads; and Figure 14 is a schematic and simplified side view of the device in

Figure 1 after beating up the weft threads.

Figure 1 is a schematic perspective view of a part of a weaving machine 1 with a device 2 according to the invention comprising a gripper device 3 and a presenting device 4 for the presenting of weft threads to the gripper device 3. According to the invention, at least a first weft thread 5 and a second weft thread 6 are inserted at the same time from a weft thread insertion side 71. The weaving machine 1 comprises a reed 10 for beating up the inserted weft thread 5, 6.

The presenting device 4 comprises a plurality of presenting members 41 to 46 which are movable between a rest position and a presenting position. In the embodiment shown, six presenting members 41 to 46 are provided. The plurality of presenting members 41 to 46 are portioned in a first set of presenting members comprising three presenting members 41 to 43 and a second set of presenting members comprising three presenting members 44 to 46. A presenting member 44 of the second set of presenting members is shown in the presenting position, while the presenting members 42, 43, 45 and 46 are shown in the rest position. One presenting member 41 of the first set of presenting members is shown in an adjustment position, which in the embodiment shown almost coincides with the rest position. A first weft thread 5 is presented by the presenting member 41 of the first set of presenting members and a second weft thread 6 is presented by the presenting member 44 of the second set of presenting members. For the sake of - - clarity, just two weft threads 5 and 6 are shown, which in the exemplary embodiment are presented by associated presenting members 41 and 44. In the embodiments shown, the presenting members 41 to 46 are presenting needles having needle eyes as thread guides.

The gripper device 3 comprises a feed gripper 30 and a receiving gripper 31 (not shown in Figure 1 ). In an embodiment, the gripper device 3 used has the features of gripper devices known from WO 2009/135636 A1 and/or WO 2010/142264 A1 , the features of which are herewith incorporated by reference. However, the features of the invention are not limited to gripper devices shown in these applications.

The feed gripper 30 is arranged to take up the first weft thread 5 and the second weft thread 6 and to insert the first weft thread 5 and second weft thread 6 at the same time into a shed 70 formed by warp threads 7. The receiving gripper 31 takes over the inserted weft threads 5, 6 from the feed gripper 30 and brings the inserted weft threads to the weft thread arrival side 72 (Figure 2), in other words the side opposite to the weft thread insertion side 71. After the receiving gripper 31 has taken over the weft threads 5, 6, the feed gripper 30 is moved back to the weft thread insertion side 71. At the instant shown in Figure 1 , the feed gripper 30 has moved back and is positioned almost outside of the shed 70. The first weft thread 5 and the second weft thread 6 extend along both sides of the feed gripper 30 and are distanced from each other in a direction towards a fell line 80 over the inserted length of the weft thread 5, 6, in particular over the full inserted length of the weft threads. More particular, a distance of the inserted length of the first weft thread 5 from a fell line 80 is smaller than a distance of the inserted length of the second weft thread 6 from the fell line 80 at the instant of crossing of warp threads 7. Hence, when the first weft thread 5 and/or the second weft thread 6 are caught by crossing warp threads 7, the first weft thread 5 will be caught first by the crossing warp threads 7. After at least one of - - the weft threads 5, 6 is caught by the crossing warp threads 7, a movement of one weft thread across the other is avoided. In order to achieve that the first weft thread 5 and the second weft thread 6 are distanced from each other in a direction towards the fell line 80 over the width of a fabric 8, the first weft thread 5 is moved relative to the second weft thread 6 at the weft thread insertion side 71 , as will be explained in more detail with the reference to Figures 2 to 13 below.

In the embodiment shown, the device 2 further comprises a support device 9 for weft threads 5, 6 comprising a thread separator 90 and a thread limiter 91. The thread separator 90 of the support device 9 separates a support area for the first weft thread 5 from a support area of the second weft thread 6. The support device 9 is known from WO 2009/135636 A1 and is described in more detail in this document. The features of WO 2009/135636 A1 are herewith incorporated by reference.

In the following, the device of Figure 1 and a method for inserting weft threads according to the invention are described with reference to Figures 2 to 13 showing top views and side views of a schematic and simplified representation of the device 2 of Figure 1. For the sake of clarity, in Figures 2, 4, 6, 7, 9, 1 1 and 13 no warp threads are shown. Throughout the drawings, the same reference numbers are used for the same or similar elements.

Figures 2 and 3 are a top view and a side view, respectively, of a schematic and simplified representation of the device 2 shown in Figure 1 when presenting the weft threads 5, 6. The presenting member 41 of the first set of presenting members is moved to a presenting position for presenting the first weft thread 5 to the feed gripper 30 and the presenting member 44 of the second set of presenting members is moved to a presenting position for presenting the second weft thread 6 - - to the feed gripper 30. As shown in Figures 2 and 3, the first weft thread 5 and the second weft thread 6 are separated by means of the support device 9 comprising the thread separator 90. As can be seen in Figure 3, the presenting member 41 presenting the first weft thread 5 is arranged and moved along a movement path that is more inclined towards a plane of the fabric 8, coinciding in the embodiment shown with a horizontal plane, than the presenting member 44 presenting the second weft thread 6. The receiving gripper 31 is moved towards the shed and the reed 10 is in its backward position.

Figures 4 and 5 are a top view and a side view, respectively, of a schematic and simplified representation of the device 2 after the feed gripper 30 has taken up the weft threads 5, 6 presented. The presenting member 41 of the first set of presenting members and the presenting member 44 of the second set of presenting members are maintained in the presenting position and only the feed gripper 30 is moved to take up the weft threads 5, 6. As shown in Figures 4 and 5, a cutting device 1 1 is provided for cutting the weft threads 5, 6 from the trailing ends of previously inserted weft threads. The receiving gripper 31 is moved inside the shed 70 to meet the feed gripper 30 and to take over the weft threads 5, 6. As can be seen in Figures 4 and 5, the weft threads 5, 6 are guided by the feed gripper 30 in two distinct positions, which are distanced from each other in horizontal and in vertical direction, this means in a direction parallel to the direction of movement 12 of the reed 10 during beat up and in a direction transversally to the insertion direction 32 and transversally to the direction of movement 12 of the reed 10 during beat up.

Figure 6 is a top view of a schematic and simplified representation of the device 2 during taking over of the weft threads 5, 6 from the feed gripper 30 by the receiving gripper 31. In the embodiment shown, the presenting member 41 of the first set of presenting members and the presenting - - member 44 of the second set of presenting members are at this instant still maintained in the presenting position.

Figure 7 is a top view of a schematic and simplified representation of the device 2 after taking over of the weft threads 5, 6 from the feed gripper 30 by the receiving gripper 31. In the embodiment shown, the presenting member 44 of the second set of presenting members is at this instant still maintained in the presenting position. The presenting member 41 of the first set of presenting members is moved relative to the presenting member 44 of the second set of presenting members into an adjustment position, which in the embodiment shown almost coincides with the rest position. Due to the movement in timing and/or in distance of the presenting member 41 of the first set of presenting members relative to the presenting member 44 of the second set of presenting members, the first weft thread 5 is moved at the weft thread insertion side 71 of the weaving machine transversally to the insertion direction 32 and away from the second weft thread 6. In this case the presenting member 41 is part of an adjustment device 47, more particularly the adjustment device 47 comprises the presenting members 41 to 43 and their drives. In the embodiment shown, the first weft thread 5 is moved towards the fell line 80. The inserted weft threads 5, 6 are held next to each other by the receiving gripper 31 and form an angle opening towards the weft thread insertion side 71 , in particular a triangle. In the embodiment shown, the weft thread 5 is moved after take over by the receiving gripper 31 and during the insertion of the weft threads 5, 6. The weft thread 5 is moved over the feed gripper 30, in particular over the element 33 of the feed gripper 30, so that the first weft thread 5 and the second weft thread 6 extend along both sides of the feed gripper 30 during the insertion by the receiving gripper 31. The first weft thread 5 and the second weft thread 6 which are conjointly held by the receiving gripper 31 and are distanced from each other at the weft thread insertion side 71 form a triangle. - -

Figure 8 is a top view of the receiving gripper 31 used in the device 2. As can be best seen in Figure 8, the two weft threads 5 and 6 are preferably held in the receiving gripper 31 in two distinct positions, which positions are distanced from each other in horizontal direction, this means in a direction parallel to the direction of movement of the reed 10 during beat up. In other words, a gripping position of the first weft thread 5 is closer to the fell line 80 (shown in Figure 7) than a gripping position of the second weft thread 6. In addition, the first weft thread 5 is moved at the weft thread insertion side 71 towards the fell line. Hence, the first weft thread 5 and the second weft thread 6 are distanced from each other over their entire inserted length.

Figures 9 and 10 are a top view and a side view, respectively, of a schematic and simplified representation of the device 2 when further inserting the weft threads 5, 6 by means of the receiving gripper 31 . In the embodiment shown, the presenting member 44 of the second set of presenting members at this instant is held slightly above the presenting position. As mentioned with respect to Figure 7, the presenting member 41 of the first set of presenting members is already located in an adjustment position, which in the embodiment shown coincides with the rest position. As can be best seen by comparison of Figures 5 and 10, in the embodiment shown the thread guide 48 of the presenting member 41 has moved in a diagonal direction in the presenting position and out of the presenting position, wherein a displacement of the thread guide 48 of the presenting member 41 in horizontal direction exceeds its displacement in vertical direction. At the instant shown in Figures 9 and 10, the warp threads 7 already started a movement before closing the shed.

Figures 1 1 and 12 are a top view and a side view, respectively, of a schematic and simplified representation of the device 2 at the end of inserting the weft threads. At this instant, the presenting member 44 of - - the second set of presenting members has been moved to its rest position. As can be best seen by comparison of Figures 5 and 10, in the embodiment shown the thread guide 49 of the presenting member 44 is also moved in diagonal direction in the presenting position and out of the presenting position. However, in contrast to the movement of the presenting member 41 of the first set of presenting members, a displacement of the thread guide 49 of the presenting member 44 in vertical direction exceeds its displacement in horizontal direction. Hence, a displacement of the thread guide 49 of the presenting member 44 does not or only marginally cause in a movement of the second weft thread 6 towards the fell line 80. At this instant just before crossing as well as at the instant of crossing of warp threads, the first weft thread 5 and the second weft thread 6 are distanced from each other over the width of a fabric 8. The weft threads 5 and 6 are caught by the warp threads 7, wherein the warp threads 7 prevent the weft threads 5 and 6 to move across each other.

Figures 13 and 14 are a top view and a side view, respectively, of a schematic and simplified representation of the device 2 shortly after beating up the inserted weft threads 5, 6. The presenting member 41 of the first set of presenting members and the presenting member 44 of the second set of presenting members are in the adjustment position and the rest position, respectively. The inserted weft threads 5 and 6 have been released by the receiving gripper 31 and are bound by the crossing warp threads 7. Following the beating up, the weft threads are woven in and the reed 10 is moved back in its backward position. The same and/or other presenting members 41 to 46 are moved in a presenting position for a subsequent insertion.

In an alternative embodiment, after crossing of the warp threads 7 the presenting member 44 of the second set of presenting members can be moved out of its presenting position to its rest position. In this case the - - presenting member 44 only moves during a third period of the weaving cycle and starting from an instant that the first weft thread 5 and the second weft thread 6 are moved away from each other and are already caught by the crossed warp threads 7. In this case as well as the presenting member 41 as the presenting member 44 move more in horizontal direction, more particularly are moved more in horizontal direction than in vertical direction.

In order to control a movement and a timing of the movement of the presenting members 41 to 46, as schematically shown in Figure 1 a control device 15 is provided for controlling the presenting device 4 and/or the adjustment device 47. The presenting device 4 is also arranged for selecting the first weft thread and the second weft thread from a plurality of weft threads and for presenting the first weft thread and the second weft thread to the gripper device.

As can be best seen in Figure 7, the second weft thread 6 is guided by the thread limiter 91 and extends during weft thread insertion substantially in parallel to the fell line 80. Due to the displacement of the first weft thread 5 at the weft thread insertion side 71 , the inserted length of the first weft thread 5 forms an angle with the fell line 80. Therefore when moving a thread guide of the presenting member 41 towards the fell line 80 as shown in Figure 7, an insertion path for the first weft thread 5 is longer than without moving the thread guide. When the first weft thread 5 is beaten up against the fell line 80 as shown in Figure 13, the first weft thread 5 is again parallel to the second weft thread 6. In a preferred embodiment, due to this longer insertion path for the first weft thread 5, a weft thread tension of the first weft thread 5 is increased and the first weft thread 5 is elongated elastically during insertion and retracts when beaten up, so that no loops are formed in the weft thread 5. In a variant, additional weft thread is supplied from a weft thread supply to compensate for the longer insertion path, wherein the first weft - - thread 5 is pulled back by a thread compensator (not shown) at the weft thread insertion side 71. In still another embodiment, the second weft thread 6 is released by the receiving gripper 31 before the first weft thread 5 is released by the receiving gripper 31 , in order to further pull on the first weft thread 5 to stretch the first weft thread 5.

In an embodiment, the weft threads 5, 6 are caught at the weft thread arrival side 72 using selvedge warp threads (not shown). In case a stretching of at least one of the inserted weft threads 5, 6 is necessary at the weft thread arrival side 72, the weft threads 5, 6 are caught only after the stretching is accomplished. Similar, an opener (not shown) for the receiving gripper provided at the weft thread arrival side 72 is controlled to ensure a stretching of the weft thread 5, 6.