TWI599691B - Weaving machine - Google Patents

Description

sewing machine

The present invention relates to a loom as described in the context of the patent application for processing a ribbon weft yarn, i.e. a relatively wide and flat belt textile unit.

The main components of the opening device, the weft insertion device and a take-up device herein are conventional devices on a loom. The woven fabric is composed of a warp yarn and a weft yarn in the form of a strip, for example, a carbon fiber ribbon or a glass fiber ribbon, which is also known for a long time. Such a strip is made, for example, from a carbon roving which is reinforced by impregnation in a state of expansion in a parallel state. The width of such a strip is, for example, several millimeters to one centimeter or more. Fabrics composed of carbon ribbons are for example used in light structural applications in the aerospace or automotive sector.

The concept of "weft" and "tape" is used herein, as the invention relates to a weft yarn introduced in the form of a strip.

The warp yarns may be any yarn, for example, a wider and/or thicker yarn, but a yarn in the form of a strip is preferably used.

A gripping and clamping device for introducing a weft thread in the form of a strip into the exposed shed of the raised and lowered warp yarns, which is gripped from the introduction side or from the opposite side (through the exposed shed) Strip the front end and pull it through the shed.

In the design of EP 1838911 A1, the introduced strip is clamped in the orientation In the clips on both sides of the shed, the strip is conveyed to the trailing edge of the fabric or the joint of the fabric by the movement of the clips in the weaving direction or the take-up direction (machine direction) by a predetermined distance. Only the outer end of the strip-shaped weft yarn is gripped and conveyed towards the trailing edge of the fabric, so in the method described in EP 1838911 A1, in principle, there is a risk that the strip is not conveyed absolutely flat to the fabric over the width of the fabric. The trailing edge, the area of the weft belt at the center of the fabric, forms an arc in the plane of the fabric. In the loom proposed in EP 1838911 A1, it is attempted to alleviate the above effect by causing the warp yarns to pass vertically through the loom, wherein the weft belts are also arranged vertically in their width directions and above the trailing edge of the existing fabric. The way to introduce the shed. This can be used as a gravity for the strip to assist in the conveying operation of the introduced ribbon weft.

DE 10 2011 009 765 B3 proposes a device and a method for returning a fabric towards the introduced ribbon weft yarn at a distance opposite to the weaving direction until the longitudinal leading edge of the strip abuts the trailing edge of the fabric.

In both cases, since the shed is closed and opened by the opening means, warp and weft crossover occurs after weft insertion. At this point, the fabric with the width of the strip is further moved or drawn a certain distance to provide space for the next weft insertion.

A disadvantage of fabrics made in this manner is that the weft yarns are positioned relative to the trailing edge of the fabric in a manner independent of the actual geometry of the strip after weft insertion.

Strips having a width of, for example, 20 mm to 50 mm are also used in practice. Such strips (due to the manufacturing method) have a certain (unnecessarily) width deviation over the length of the strip.

For some applications, it is preferred to use certain ribbon weft yarns that have different widths that are specifically selected in the fabric range, either alternately or in a certain order.

There are also certain fabrics that have a predetermined distance between their successive ribbon weft yarns. When the width of the strip fluctuates, there is a danger that such a distance does not always have the preset value.

EP 1838911 A1 proposes a device with a sensor which measures the strip width during the weaving operation. The input device for the warp yarns is controlled according to the measured width to wind the fabric without stress or even with excess warp yarns. Therefore, depending on the different widths of the ribbon weft yarns, if there is no distance from the trailing edge of the fabric or there is a predetermined distance, the longitudinal edges of the ribbon weft yarns cannot be accurately positioned.

It is an object of the present invention to provide a looms in which the fabrics of the belt-like weft yarns are formed with different geometrical parameters of the strips, in particular with different widths.

The solution to achieve the above object of the present invention is characterized by the first item of the patent application. The main advantage of this solution is that it can take into account, in particular, the actual width and width fluctuations of the strip introduced into the fabric, since it can be fed based on a variable distance (rather than as specified in the prior art) The evaluated measurements are such that the strip moves toward the fabric. This makes it possible, for example, to obtain a closed fabric pattern when the current broadband of the strip to be introduced is reduced.

Overall, the present invention significantly increases flexibility in weft insertion because the control device can be used to transmit instructions for fabric feeding to the take-up device based on the evaluated measurements, and the measurements will correspond The actual strip width is taken into account.

As an alternative to performing width detection (preferably as a supplement), the measuring device is adapted to detect other geometrically measured variables, such as holes and/or bonds in the weft yarn, wherein the latter is due to one or more lengths The silk is produced by falling off from the strip composite.

According to an advantageous embodiment of the invention, the measuring device is based on an optical measuring method. This optical measurement means, in particular, an optical scanning measurement field that preferably extends over the width of the strip. Corresponding measuring devices are, for example, optical precision micrometers.

According to an alternative, the measuring device operates in particular acoustically by means of ultrasound. The width of the scanned strip is determined by the wave propagation of the visible ultrasonic wave.

A column scan camera with combined pattern recognition software can also be used.

Another measurement is based, for example, on a tactile (ie not non-contact) scan of the introduced weft (strip).

More preferably, the measuring device is constructed such that the width of the weft yarn to be tested is continuously detected before and/or during the introduction. This enables continuous measurements for detecting all fluctuations associated with the strip width. This significantly expands the corresponding evaluation scheme.

The measuring device according to the invention is preferably arranged such that it can measure the width value of the next weft to be introduced and/or currently to be introduced, wherein the measurement can be carried out over the entire length of the weft to be introduced. By this measurement, the fabric can be moved to the strip at a distance associated with the evaluation result based on the evaluated measurements immediately after weft insertion.

The fabric is then fed along the warp together with the previously introduced tape. To carry out such conveying operations, a drivable take-up roll and (preferably) a fabric clip are provided as part of the take-up means. The fabric clip is preferably disposed in the region of the trailing edge of the fabric that moves in the weft direction and prevents the ribbon weft yarn that was previously introduced into the fabric from moving during the movement of the fabric.

In the case where the aforementioned relative movement of the strip and the fabric is not carried out (for example, because the distance between the strip and the fabric has reached the desired level), the take-up device allows the fabric to be immediately taken along with the previously introduced strip. The direction is further by a distance associated with the evaluation result Exercise or feed.

In order to create a reverse fabric movement, as an alternative to the reverse rotation of the take-up rolls, it is preferred to effect the oscillating movement of the intermediately connected steering rolls during the warp movement or during the movement of the fabric. In this case, the take-up device comprises an oscillatingly supported and reversibly drivable steering roller disposed between the shed or the fabric clip and the drivable take-up roll during the movement of the fabric.

Preferably, the measuring device is arranged on the introduction side of the weft or strip and is preferably oriented in the warp direction, ie transverse to the weft direction. Therefore, the measuring device can also be mounted in a narrow space and still reliably detect the entire width of the weft yarn.

Alternatively, the measuring device is arranged below and above the weft yarns and is preferably arranged in the region of the longitudinal edges of the fabric which first intersect the strip during the weft insertion process. In this way, the width of the strip currently drawn through the shed can be measured almost over the entire length.

The evaluation device is preferably constructed such that it can calculate the minimum width and/or the maximum width of the weft yarn to be introduced. Based on all measured measurements relating to the weft yarns, the limit values can be simply determined to correspondingly control the take-up device depending on the desired fabric pattern, thereby producing, for example, between successive weft yarns. Constant distance. To this end, the maximum width of the current weft yarn is determined and the fabric transport is carried out in the advancing direction according to the desired distance (as appropriate, along with the aforementioned transport in the retreating direction towards the strip).

Alternatively or additionally, the evaluation device is preferably constructed such that it can calculate a mixed value, in particular an average width of the weft yarn, based on a plurality of measured values of a weft yarn to be introduced or introduced. With this average value, the take-up device can be controlled in such a way that a monolithic visual fabric pattern is obtained, the distance of the currently introduced weft or strip from the trailing edge of the fabric Matches the above average. The distance can also be adjusted such that the corresponding weft yarn abuts against the trailing edge of the fabric based on the measured blending value, depending on the width of the strip and the trailing edge of the fabric (including several voids as appropriate) set.

As an alternative or a subsequent solution to the relative movement of the previously introduced weft yarn and the fabric, the fabric can be moved further by the controlled take-up device before the introduction of the next weft yarn, so that it does not The trailing edge of the fabric is formed into any void or spaced apart from the trailing edge of the fabric to introduce the next weft yarn.

In the presence of a fluctuation in the width of the strip, it is also possible to achieve a fabric pattern in which the strip partially collides with adjacent strips by its two longitudinal edges, while the narrower strip sections form corresponding voids.

Advantageously, the evaluation device and/or the control device are constructed and designed such that at least the next weft insertion and the extraction device are suspended and/or if the predetermined weft width is exceeded and/or lower. A preset signal is output. That is, the evaluation device and/or the control device are preferably capable of stopping the weaving operation based on the measured limit value in terms of the strip width, thereby preventing erroneous production.

As a solution similar to the above, the evaluation device is preferably constructed such that it can identify errors in the weft yarn to be introduced, such as holes and/or bonds, and in this case trigger a certain of the loom Preset actions. Such an action may, for example, refer to suspending the weft insertion device and/or outputting a predetermined signal to, for example, recruit a machine operator.

1‧‧‧ warp yarn

2‧‧‧ Weft yarn (tape)

3‧‧‧ shed

4‧‧‧ fabric

5‧‧‧ fabric trailing edge

6‧‧‧ warp direction, warp direction

7‧‧‧ Weft yarn tray, storage tray

8‧‧‧Rotary axis

9‧‧‧Storage disk

10‧‧‧Opening device

11‧‧‧Drives for opening devices

20‧‧‧Weft insertion device

21‧‧‧Clamping and cutting device

22‧‧‧Driver for gripper

23‧‧‧Scratch head

24‧‧‧ grasping pole

25‧‧‧Complementary shaft

29‧‧‧ fulcrum

30‧‧‧Exporting device

31‧‧‧Drives for the take-up rolls

32‧‧‧ lead-out roller

33‧‧‧Rotary axis

34‧‧‧steering roller

35‧‧‧Drives for fabric clips

36‧‧ ‧ fabric clip

37‧‧‧steering roller

38‧‧‧Retraction distance

39‧‧‧Forward distance

40‧‧‧Measurement device

41‧‧‧ Receiver

45‧‧‧Evaluation device

50‧‧‧Control device

Figure 1 is a plan view of the loom; Figure 2 is a schematic view of the looms of Figure 1 from the input side of the warp yarns; and Figure 3 is a cross-sectional view of the looms of Figures 1 and 2 with the viewing direction along the weft direction.

The invention will now be described in detail in connection with an embodiment.

Figures 1, 2 and 3 schematically show a loom for warp and weft in the form of a strip. The strips are composed, for example, of carbon and/or glass fibers. This kind of loom is also known as a webbing machine.

Alternatively, the above embodiment of the loom can also be applied to the following fabrics: only the weft yarn is present in the form of a strip, and the warp yarn is embodied as a conventional yarn, preferably as a thicker (i.e. thicker) And / or wider) yarn.

A plurality of side by side warp yarns 1 are held in a plurality of rotary storage trays 9 and conveyed in the warp direction 6 (also called the machine direction or the weaving direction) to the opening means 10, 25. The opening means comprises a twisted wire (not shown) through which the warp yarn 1 passes. Preferably, the strands are incorporated into a (shown as framed) heald shaft 25 and alternately raised or set by the drive unit 11 such that the warp yarns 1 guided by the strands are in a conventional manner A shed 3 is formed therebetween. If half of the warp yarns 1 are deflected to the maximum position above them and the other half is deflected to the maximum position below it, the weft yarns 2 can be guided through the formed sheds 3. In order to store the weft yarn 2 embodied here as a strip, a storage tray 7 is provided which is rotated about the axis of rotation 8 and which is arranged on one side of the loom. As an alternative to the storage trays 9, the warp yarns 1 can also be held on the same storage device, such as on a warp beam.

A weft insertion device 20 for introducing the weft yarn 2 into the shed 3 is provided, which comprises a drive device 22, a gripping rod 24 connected to the driving device 22, and a gripping head 23 disposed on the free end of the gripping rod 24 . The grip bar 24 is movable back and forth through the exposed shed 3 by the drive unit 22. As an alternative to the gripping rod 24, a gripping belt can also be used, but it must be in its path as the case may be. Must be guided by the shed.

Before the weft insertion is carried out, the weft yarn 2 provided by the weft disc 7 is first fixed in the region of its free end by means of a clamping and cutting device 21, which is only schematically illustrated, and then the gripping head 23 passes through the shed 3 The free end of the weft yarn 2 is grasped and clamped. Then, the clamping and cutting device 21 releases the free end of the weft yarn 2 so that the gripping head 23 draws the weft yarn 2 through the shed 3. Subsequently, the shed 3 is closed by the downward or upward movement of the warp yarn 1. Furthermore, the clamping and cutting device 21 clamps the weft yarn 2 on the side of the weft disc 7 and separates the previously introduced weft yarn 2 from the continuous weft yarn 2 provided by the weft disc 7.

Figure 2 shows the shed 3 starting from the back of the loom, which is formed by alternating warp yarns 1 moving up and down so that the weft yarns 2 subsequently provided by the weft discs 7 are conveyed through the sheds 3. To effect clamping and release, the jaws of the gripping head 23 have a fulcrum 29, which is only schematically shown. Of course, the jaws of the gripping head 23 can also perform pure linear motion. For example, the clamping and release of the jaws can be effected by a mechanical control device disposed outside the shed; pneumatic or electromechanical controls can also be used.

According to an unillustrated alternative, the weft yarn 2 is gripped by a gripper which has not previously moved through the shed towards the weft thread, but rather on one side of the weft disc, where it grips the end of the weft thread , transport it through the shed, release the weft yarn and move back to the weft yarn without weft.

The introduced weft yarn 2 still needs to be combined with the fabric 4. To achieve this, the trailing edge or joint 5 of the fabric is moved with the fabric 4 towards the introduced weft yarn 2 before or during closure of the shed 3. For this purpose, the fabric 4 is moved over its entire width by a certain receding distance 38 against the warp direction 6 towards the previously introduced weft yarn 2 until, for example, the fabric trailing edge 5 abuts against the weft yarn 2 On the longitudinal edge. The fabric 4 is preferably clamped by a fabric clip 36 driven by a drive unit 35 (see Figures 1 and 3). The clamping, as the case may be, is then released through the fabric clip 36 and is advanced further against the warp direction 6 until the fabric clip 36 can grasp and clamp the weft yarn 2 together. Subsequently, the fabric clip 36 is moved along with the clamped fabric 4 along the warp direction 6 at a forward distance 39 to form the next shed 3.

The fabric 4 which has been continuously grown in the above manner is wound around the take-up roll 32, which is rotationally driven by the driving device 31 around the rotary shaft 33. In order to produce the forward and backward movement of the fabric 4, in this embodiment, the oscillating motion of the intermediately connected steering rollers 34, 37 is achieved during warp movement or during the movement of the fabric. In this embodiment, such a oscillating movement of the steering rollers 34, 37 is effected actively by a reverse pivoting drive (not shown) which synchronizes the two deflection rollers 34, 37 motion.

The take-up rolls 32 and the fabric clips 36 and, as the case, the steering rolls 34 are part of a take-up device 30 in which the drive means of the devices must be precisely coordinated. This operation is undertaken by the control unit 50 (see the description of the invention hereinafter).

The steering roller 34 is disposed between the shed 3 and the take-up roller 32 during the movement of the fabric. Also included in this region is a fabric clip 36 which is preferably disposed in the region of the trailing edge 5 of the fabric. In the area behind the loom, the optional diverting roller 37 is disposed on the countershaft 25 and the storage tray. Between 9.

In principle, the oscillating movement of the deflection rollers 34 and 37 can also be omitted. In this case, the forward and backward movement of the fabric 4 must be carried out by correspondingly controlling the drive unit 31 for the take-up roller 32. To compensate, for example, a corresponding drive for storing the disc 9 needs to be provided in the area behind the machine.

Practice has shown that, in particular, the width of the weft yarn 2 fluctuates due to the manufacturing process, so that in the case of the prescribed distance 38 (for the backward movement) and the distance 39 (for the subsequent forward movement), unevenness is generated. The fabric pattern is not intended for all uses.

In view of this, according to the invention, a measuring device 40 is provided for detecting the geometrical parameters, in particular the width, of the weft yarns before the weft yarns 2 are introduced into the corresponding sheds 3. In the present embodiment, the measuring device 40 is disposed below the weft yarn 2 between the weft disc 7 and the clamping and cutting device 21.

The measuring device 40 is here based on the principle of optical measurement and scans the weft thread 2 . The measuring device 40 can be constructed, for example, as an optical precision micrometer. The optical signal reflected back from the weft yarn 2 is received by the measuring device 40. As an alternative or in addition, a receiver 41 (shown in dashed lines in Fig. 2) is arranged above the weft yarn 2. The principle of the measuring device 40 for detecting geometrical parameters of a long strip of cloth (e.g., geometrical parameters of the strip) is known to us and need not be described.

In the present embodiment, the measured value or measurement result detected by the measuring device 40 is transmitted to the evaluation device 45, and the evaluation device evaluates the measurement result and transmits the evaluation result (also referred to herein as the evaluated measurement result). To the control device 50. The control device 50 is coupled to the take-up device 30 and controls the movement of the fabric 4 by the oscillating back and forth movement of the steering rollers 34, 37 and the fabric clip 36, and the winding of the fabric 4 in the take-up On the drum 32, control is performed. In this case, the control device 50 and the driving device for the oscillating motion of the steering rollers 34, 37, and (as appropriate) the driving device 35 for driving the fabric clip 36, and the driving device 31 for driving the take-up roller 32 , there is a connection.

In general, the signal lines and control lines are indicated by dotted lines in FIGS. 1 and 2.

The measuring device 40 is preferably adapted to continuously measure the geometry of the weft yarn 2. This makes it possible to reliably detect all deviations (width, holes, side flaking) from the ideal shape. Preferably, the measurement is carried out only in the case where the weft yarn 2 passes through the measuring device 40.

The continuous measurement preferably also comprises a measurement of the section of the weft thread 2 situated in the measuring region: the weft thread belongs to the next weft thread 2 to be introduced during its clamping by the cutting device 21 . The evaluation device 45 preferably also takes into account the measured values associated with the above-mentioned situation such that the measured values are within the total length of the next weft yarn 2 to be introduced.

The evaluation device 45 is preferably constructed such that it can calculate the minimum width and/or maximum width of the weft yarn to be introduced. As an alternative or in addition, the evaluation device 45 can calculate a mixed value, in particular a width average of the weft yarn, based on a plurality of measured values of the weft yarn 2, for example.

Based on the evaluation by the evaluation device 45, the drive means of the deflection rollers 34, 37 and, as the case may be, the drive means 35 of the fabric clip 36 can be controlled by the control means 50 based on the measured weft width (eg based on The weft width or a measured value associated with a blending value causes the fabric 4 to be reversed back to the warp 6 with a certain adjusted distance 38. The subsequent reverse movement 39 of the fabric 4 along the warp direction 6 is also correspondingly adjusted so that the advancement distance 39, as with the receding distance 38, can vary depending on the particular evaluation. Unlike the prior art, the above solution does not set a constant predetermined motion of the fabric 4 after each weft insertion, but sets a motion that matches the actual width of the previously introduced weft yarn. Similarly, the oscillating motion of winding the fabric 4 to the take-up roll 32 and the deflecting roll 34 between the take-up roll 32 and the fabric clip 36 is controlled based on the currently measured weft width.

The drive means for controlling the different movements of the aforementioned components of the loom are preferably embodied as individually controllable motors or as preferably self-controlling means 50 motor-transmission combination for receiving signals. The drives are configured to perform a reverse pivoting, rotational or linear motion (as needed).

The control device 50 can control the take-up device 30, particularly the steering roller 34 and the fabric clip 36, in a manner such that the fabric 4 is positioned according to different types prior to the introduction of the next weft yarn. For example, it is thus possible (by taking into account the width of the corresponding weft yarn 2 always) that the fabric 4 does not have any voids. Alternatively, the fabric 4 can also be positioned prior to the next weft insertion such that each weft yarn 2 is always spaced a distance from the trailing edge 5 of the fabric to create a fabric pattern with voids between successive weft yarns 2. According to a further alternative, the take-up device 30 is controlled such that, along the currently introduced weft yarn 2 which varies in width, one or more gaps are formed with the trailing edge 5 of the fabric, wherein in the remaining region, the weft yarn 2 collides An overlap region is formed on the trailing edge 5 of the fabric and/or even with the trailing edge 5 of the fabric.

The mixed form of the above fabric pattern can also be easily achieved by correspondingly adjusting the control device 50.

Preferably, the evaluation device 45 and/or the control device 50 are constructed and designed such that at least the next weft insertion and withdrawal device 30 is suspended and/or if the predetermined weft width is exceeded and/or lower. Or output a preset signal. Likewise, the evaluation device 45 is preferably capable of identifying errors in the weft yarn 2 to be introduced, such as holes and/or bonds, and can trigger a predetermined action of the loom (especially through the control device 50).

The invention is not limited to the embodiments shown and described herein. Modifications may also be made within the scope of the patent application, such as combining the features illustrated and described in the various embodiments.

1‧‧‧ warp yarn

2‧‧‧ Weft yarn (tape)

4‧‧‧ fabric

5‧‧‧ fabric trailing edge

6‧‧‧ warp direction, warp direction

7‧‧‧ Weft yarn tray, storage tray

8‧‧‧Rotary axis

9‧‧‧Storage disk

20‧‧‧Weft insertion device

21‧‧‧Clamping and cutting device

22‧‧‧Driver for gripper

23‧‧‧Scratch head

24‧‧‧ grasping pole

25‧‧‧Complementary shaft

30‧‧‧Exporting device

31‧‧‧Drives for the take-up rolls

32‧‧‧ lead-out roller

33‧‧‧Rotary axis

34‧‧‧steering roller

35‧‧‧Drives for fabric clips

36‧‧ ‧ fabric clip

37‧‧‧steering roller

38‧‧‧Retraction distance

39‧‧‧Forward distance

40‧‧‧Measurement device

45‧‧‧Evaluation device

50‧‧‧Control device

Claims (10)

A looms having an opening device (10) for forming a shed (3) between the warp yarns (1) drawn from the preliminary yarn (9), a weft insertion device (20) for the form Introducing the formed sheds (3) for the weft yarns (2) of the strip, and a take-up device (30) for leading the fabric (4) formed by the warp yarns and the weft yarns (1, 2) after the introduction of the weft yarns , characterized by a measuring device (40) for detecting the geometric parameters of the weft yarn, in particular the width, before the weft yarn (2) is introduced into the formed shed (3), the evaluation device (45) for The measured measurement results are evaluated, and a control device (50) is provided in connection with the extraction device (30) for controlling the movement of the fabric (4) along with the extraction based on the evaluated measurement results. A loom according to claim 1, characterized in that the measuring device (40) is based on at least one of the following measuring methods: an optical measuring method, wherein the measuring device (40) is preferably constructed as an optical precision measuring device. Micrometers, and/or acoustics, especially those that operate by ultrasound, measurement methods, and/or tactile measurements. A loom as claimed in claim 1 is characterized in that the measuring device (40) is constructed and designed to continuously detect the width of the weft yarn (2). A loom according to any one of claims 1 to 3, characterized in that the measuring device (40) is arranged such that it can measure the width value of the next weft yarn (2) to be introduced or The width value of the weft yarn is measured during the introduction of a weft yarn (2), wherein the measurement can be carried out on the moving weft yarn (2). A loom according to any one of claims 1 to 3, characterized in that the evaluation device (45) is constructed to calculate the minimum width and/or the maximum width of the measured weft yarn (2). A loom according to claim 5, characterized in that the evaluation device (45) is constructed based on a plurality of measured values of a weft yarn (2) to be introduced or during the introduction of a weft yarn (2) A plurality of measured values of the weft yarn are used to calculate a mixed value, in particular an average width of the weft yarn. A loom according to any one of claims 1 to 3, characterized in that the take-up device (30) comprises a drivable take-up roll (32). A loom according to claim 7 is characterized in that the take-up device (30) comprises a swingable drive steering roller (34) which is arranged at the shed during the movement of the fabric (3) Between the driveable take-up roll (32). A loom according to any one of claims 1 to 3, wherein the take-up device (30) comprises a fabric clip (36), and the take-up device (30) can be controlled as such The device (50) controls such that the fabric (4), together with the fabric clip (36), is reversed in the weave direction by a predetermined distance, preferably determined based on the evaluated measurements. The shift, preferably back, to the extent of a collision with the previously introduced weft yarn (2). A loom according to any one of claims 1 to 3, characterized in that The take-up device (30) is controlled, the fabric (4) being positionable before the next weft insertion, such that the weft yarn (2) can be introduced in one of the following ways: not within the entire latitude and longitude range The trailing edge (5) of the fabric forms any void, or is spaced from the trailing edge (5) of the fabric throughout the length of the weft, or forms one or more voids with the trailing edge (5) of the fabric throughout the length of the weft. It partially rests on the trailing edge (5) of the fabric and/or overlaps the trailing edge (5) of the fabric.