This invention relates to a method for simultaneously weaving two distance fabrics. A distance fabric is a fabric comprising two layers of woven yarns separated by an empty space. In some particular cases, this space can be filled in with different materials, such as a particulate material. Such a distance fabric is sometimes qualified as “three-dimensional structure” and is particularly adapted to be used as artificial turf for sport grounds.
A woven artificial turf is known from WO-A-2007/116290 and includes pile yarns which extend, on two respective heights, from a base layer. This artificial turf can be woven on a face-to-face carpet loom. During weaving, some loops are provided to help the piles to stay upright. These loops provide poor elasticity of the turf.
On the other hand, BE-A-1007679 discloses a method for weaving two fabrics having each an inner layer which faces the other fabric during weaving and an outer layer. Connecting warp yarns extend between the inner and outer layers and bind them together. The pattern of those connecting yarns is quite simple since the associated shedding system provides only two positions. Pile warp yarns are interlaced in both inner layers. The required shedding system can provide three positions with respect to both inner weft insertion zones. Since they are interlaced in the inner layers, pile yarns are not held strongly enough for flooring applications. Connecting layer yarn consumption and yarn density are high, in particular on the inner layer of each fabric. This makes it difficult to introduce between the layers of each fabric a particulate material such as sand or rubber granulates. Therefore, such a fabric would not be appropriate to be used as an artificial turf.
The invention aims at solving these problems with a new method which makes it possible to simultaneously weave two distance fabrics with high productivity. Their structure can be sophisticated but still easy to produce. Such fabrics can be used as artificial turf or for other purposes.
This invention concerns a method for simultaneously weaving two fabrics provided with piles, said method comprising at least the steps of:
wherein
Thanks to the invention, “three dimensional structures” are no more limited to simple structures since it is possible to manage the shedding elements to take into account on one side geometrical information such as distance from beating points and insertion zones and on the other side patterning information. In particular, two distance fabrics can be manufactured with a high productivity and the connecting warp yarns can efficiently bind the inner and outer layers of each fabric, while they do not lower the elasticity of the fabrics and do not hinder filling of the space between the two layers of each fabric with a particulate material. Moreover, the pile warp yarns can be securely anchored to some layers of the fabrics and participate to the global elasticity of the fabrics.
According to advantageous but non compulsory aspects, a method according to the invention can incorporate one or several of the following features:
The invention also concerns a fabric which can be woven with the method mentioned here-above and, more particularly, a fabric comprising a woven front layer, a woven back layer, connecting yarns extending between the front and back layers and pile yarns protruding from the front layer wherein the pile warp yarns are at least interlaced into the back layer of the fabric and go through its front layer.
According to advantageous aspects of the invention, such a fabric can incorporate one or several of the following features:
According to another aspect, the invention also concerns a loom which can be used to perform the method mentioned here-above in order to produce the fabric mentioned here-above. Such a loom is for simultaneously weaving two fabrics provided with an inner layer, an outer layer, connecting warp yarns extending between the inner and outer layers and pile yarns extending between the fabrics. This loom comprises, or is connected to, shed forming means and weft insertion means. According to the invention, the loom further comprises two sets of lancet means adapted to keep the inner and outer layers of each fabric apart from each other during weaving and said loom further comprises computation means adapted to select, for each pick and for each connecting warp yarn and each pile warp yarn, on the basis of the information relating to the layer in which said warp yarn has been interlaced in the previous pick, on the basis of the shedding pattern and amongst several predetermined positions, a position to be taken by a shedding element driving said warp yarn during said pick, where said warp yarn does not interfere with said weft insertion means.
The invention will be better understood on the basis of the following description which is given in correspondence with the annexed figures and as an illustrative example, without restricting the object of the invention. In the annexed figures:
A face-to-face three rapier sets loom 2 is represented on
Three sets of rapiers, comprising respectively a bringer and a taker, are used in loom 2, namely a top rapier set 12, an intermediate rapier set 14 and a bottom rapier set 16.
Frames 10 are driven by their respective servomotors in order to bring the warp yarns into respective positions where they participate to the shed and do not interfere with the rapier sets 12-14-16 during insertion. Each frame 10 forms thus a shedding element for loom 2.
A double lancet 20 is introduced in each reed space and comprises a main rod 201, an upper finger 202 and a lower finger 204. Parts 201, 202 and 204 are integral with each other. Lancets 20 are distributed on the width of loom 2.
As shown on
The shape of the lancets 20 is such that the intermediate rapier set 14 can travel between the respective fingers 202 and 204 of each lancet, without interference.
Top ground part 422 comprises a back layer BL2 and front layer FL2. Similarly, bottom ground part 442 comprises a back layer BL4 and a front layer FL4. Back and front layers are separated by an empty space in each fabric. Back layers BL2 and BL4 are woven externally with respect to fingers 202 and 204, whereas front layers FL2 and FL4 face each other in a center part of loom 2 defined between fingers 202 and 204 of the respective lancets 20. Therefore, back layers BL2 and BL4 form outer layers, whereas front layers FL2 and FL4 form inner layers of upper and lower fabrics 42 and 44. The pile set 424 and 444 extend between inner layers FL2 and FL4.
In the present description, the terms “outer” and “inner”, “external” and “internal”, “externally” and “internally” are defined with respect to a central plane π of loom 2 which lies between fingers 202 and 204 and includes the cut line of cutting device 6. An object is “internal” or “inner” with respect to another item when it is closer to plane π as this item. Conversely, an object is “external” or “outer” when it is further away from plane π with respect to another item.
Three insertion zones are provided in loom 2 for rapier sets 12, 14 and 16 and they are located symmetrically with respect to a plane π, the insertion zone for set 14 being centered on this plane.
In the example, fabrics 42 and 44 are used as artificial turf and all yarns constituting these fabrics are synthetic, e.g. made of polyethylene because of its low coefficient of friction.
Outer or back layer BL2 comprises a filling warp yarn 101 and a binding warp yarn 102 which are woven with outer weft yarns 301 introduced within the shed, at every pick, by top rapier set 12, regularly under and above yarn 101 and above and under yarn 102.
Inner or front layer FL2 comprises a filling warp yarn 103 and a binding warp yarn 104 woven with inner weft yarns 302 which are introduced within the shed by intermediate rapier set 14, at every second pick.
A connecting warp yarn 401 extends between inner and outer layers FL2 and BL2 in order to bind these layers. The connecting warp yarn 401 is woven according to 12 pick repeat.
At pick P1, connecting warp yarn 401 goes externally with respect to outer weft yarn 301. At pick P2, connecting warp yarn 401 goes internally with respect to outer weft yarn 301, that is under this yarn in the representation on
At pick P9, connecting warp yarn 401 moves back to outer layer BL2 and goes externally with respect to weft yarn 301. At pick 10, yarn 401 goes internally with respect to weft yarn 301 and, at pick 11, it goes externally with respect to weft yarn 301. At pick 12, connecting warp yarn 401 moves back to front layer FL2. At pick 13, connecting warp yarn 401 moves back to outer layer BL2 and recover the position of pick 1.
In other words, connecting warp yarn 401 follows a W-shaped path within back layer BL2, during picks 1, 2 and 3, 9, 10 and 11. On the other hand, connecting warp yarn follows a W-shaped path within front layer FL2 during picks 4, 6 and 8. The density of the path of warp yarn 401 in inner layer FL2 is lower than its density in outer layer BL2, since inner weft yarns 302 are woven only on every second pick within front layer FL2.
Similarly, outer or back layer BL4 includes a filling warp yarn 105 and a binding warp yarn 106 whereas front layer FL4 includes a filling warp yarn 107 and a binding warp yarn 108.
Outer weft yarns 303 are introduced within the shed corresponding to back layer BL4 by bottom rapier set 16 at each pick, whereas inner weft yarns 304 are introduced within front layer FL4 at every second pick, odd picks in the example in
A second connecting warp yarn 402 is used to bind inner and outer layers FL4 and BL4 in a way similar to yarn 401. More precisely, connecting warp yarns 402 follows a W-shaped path within inner layer FL4 between picks P1 and P5, by going around, alternatively externally and internally, inner weft yarns 304. Then, warp yarn 402 goes from inner layer FL4 to outer layer BL4 where it follows a W-shaped path, around outer weft yarns 303, at picks P6, P7 and P8, before going back to front layer FL4. At pick 10, connecting warp yarn 402 goes back to outer layer BL4 where it follows a W-shaped path around outer weft yarns 303, at picks P10, P11 and P12.
Therefore, connecting warp yarns 401 and 402 can be said to be W-inwoven within inner and outer layers FL2, FL4, BL2 and BL4, which guarantees that these yarns efficiently hold together the layers of each fabric 42 and 44, these fabrics being qualified as “distance fabrics” insofar as their respective front and back layers can be kept at a distance.
In the meaning of the invention, a warp yarn is “W inwoven” in a layer when it is interlaced with at least three adjacent weft yarns in the same layer. This is the case when a warp yarn follows a W-shaped path with the adjacent weft yarns in the same layer. More precisely, when considering three adjacent weft yarns, the warp yarn goes externally with respect to the two extreme weft yarns and internally with respect to the intermediate weft yarn or internally with respect to the two extreme weft yarns and externally with respect to the intermediate weft yarn. In the meaning of the invention, a warp yarn is also “W inwoven” in a layer when it is interlaced with five adjacent weft yarns in the same layer. For five adjacent weft yarns, the warp yarn goes externally with respect to the first, third and fifth weft yarns and internally with respect to the second and fourth weft yarns or internally with respect to the first, third and fifth yarns and externally with respect to the second and fourth yarns.
Pile warp yarns also belong to fabrics 42 and 44. A first pile warp yarn 501 goes externally around outer weft yarn 301 at pick P1 and follows the same W-shaped path as yarn 401 within back layer BL2 at picks P1, P2 and P3. At pick P4, pile warp yarn 501 moves from back layer BL2 to front layer FL2 and goes between weft yarns 301 and 302. At pick P5, pile yarn 501 goes between weft yarns 303 and 304. At picks P6, P7 and P8, pile yarn 501 follows a W-shaped path within back layer BL4. Between picks P8 and P9, pile warp yarn 501 crosses inner layers FL4 and FL2 and reaches, at pick 9, the same configuration as at pick P1. In other words, pile war yarn 501 is W-inwoven in back layers BL2 and BL4 whereas it goes through layers FL2 and FL4, when it changes from one fabric to the other.
Another pile warp yarn 502 is represented on
When a fabric according to the invention is used as an artificial turf as shown on
The pile warp yarns are moved between their respective positions represented on
On
Considering that positions A2 and A4 are identical, seven positions are required to weave pile warp yarn 501 within the respective layers FL2, BL2, FL4 and BL4 of the upper and lower fabrics 42 and 44, according to the shedding pattern represented on
These seven positions can be programmed thanks to electronic control unit 50 which controls the four servomotors 40 driving the first four heddle frames 10 of loom 2. Those positions are compatible with the pattern which expresses the theoretical position of the warp yarns with respect to the insertion means. They also geometrically allow insertion means to introduce weft yarns without damaging warp yarns.
In order to achieve the above-mentioned positions of pile warp yarn 501, microchip 52 computes, at each pick, the position A1-A8 to be taken by this yarn, actually the position of a heddle frame 10 supporting a heddle which drives this yarn. Data relating to the shedding pattern to be obtained by the set of servomotors 40 is stored in memory 54. On the basis of this data, it is possible for microchip 52 to determine, for each pick, in which layer pile warp yarn 501 has been interlaced in the previous pick, this layer being considered as an “origin layer”. This gives the starting point of the line representing the position of yarn 501 on
Actually, if one considers pile warp yarn 501 interlaced in one of layers BL2, FL2, BL4 and FL4, it can take four positions, namely a first position above top rapier set 12, a second position between top and intermediate rapier sets 12 and 14, a third position between intermediate and bottom rapier sets 14 and 16 and a fourth position under bottom rapier set 16. In other words, if N is the number of rapier sets, pile warp yarn 501 originating from one layer can take N+1 positions. Pile warp yarn 501 can be interlaced in either one of layers BL2, FL2, BL4 and FL4 so that it can actually take M×(N+1) positions, where M is the number of layers where pile warp yarn 501 is to be interlaced according to the shedding pattern. In the example represented on the figures, M equals 4.
If a pile yarn is to be interlaced in four layers, its position will have to be selected amongst 4×(3+1)=16 predetermined positions.
Because of the specific pattern represented on
Thanks to the invention, the respective positions A1-A8 of the pile warp yarns can be achieved without interference between these yarns and the insertion zones of the weft yarns. The four frames 10 represented on
Practically, the seven reference positions of the pile warp yarn 501 depend on the weaving pattern, the location of the beating point of the concerned layer and the distance between the heddle and the beating point of the concerned layer. They can be stored in memory 54 of the electronic control unit 50. While weaving, electronic control unit 50 determines at each pick the right position of the heddle amongst the stored reference positions and according to the pattern and the layer in which the warp yarn was previously interlaced. This kind of method allows advantageously changing pattern or geometrical parameters that affect reference positions independently. For example, if the distances between layers are modified, the reference position must be changed in a way that still allows the insertion means to function without damaging the warp yarns.
The same approach can be followed for pile warp yarn 502 and any other pile warp yarn which is not represented and belongs to fabrics 42 and 44. Unlike pile warp yarn 501, pile warp yarn 502 does not goes from top ground part 422 to bottom ground part 442 in a straight vertical way. For example at pick P8, pile warp yarn 502 is placed in position A4 and remains in this position at pick P9 so that inner weft yarn 304 and outer weft yarn 303 are inserted under pile warp yarn 502. In other words, pile warp yarn 502 goes from top ground part 422 to bottom ground part 442 over one pick, that is pick P9. The result is that the pile warp yarn 502 is slightly on the skew.
Once cut, the pile warp yarn 502 will tend to recover a vertical position but be longer than the cut pile yarn 501. This is advantageous in case of artificial turf because the appearance of the carpet will be then closer to natural turf since the piles will have two different lengths, like grass blades. It is also possible to obtain more than two different lengths for the piles of the fabric, by having the pile yarns 501, 502 or equivalent pile yarns following different paths between back layers BL2 and BL4.
As shown on
If one considers for example an artificial turf application, the pile yarns 501 and 502 extend from one back layer BL2 to the other BL4 on a distance of about 70 mm and the distance between the back layer and the front layer in each fabric 42 and 44 is about 15 mm. In these conditions, some positions B1-B8 are so close to each other that they can be merged. For instance, positions B1 and B3 can be merged together. The same applies for positions B2, B5 and B6 and for positions B4 and B8. Therefore, the frame moving connecting yarn 401 can be driven with three reference positions.
As for pile warp yarns, the position of the heddle frames driving the connecting warp yarns are determined by electronic control unit 50 on the basis of the layer in which each connecting warp yarn is interlaced in a previous pick and on the basis of the shedding pattern to be followed. However connecting warp yarns are interlaced in two layers which are fed with weft yarns with the help of two rapier sets. Each position is selected amongst 2×(2+1)=6 predetermined positions since any connecting warp yarn can be interlaced in one of layers BL2 and FL2 or BL4 and FL4 and might have to go externally with respect to outer weft yarns 301, and 303, between inner and outer weft yarns or between inner weft yarns 302 and 304.
As shown on
This can also be achieved with electronically driven electrical servo actuators, similar to motors 40, driven by electronic control unit 50 as explained here-above.
In the second embodiment of the invention represented on
Each layer BL2, FL2, BL4 or FL4 of a fabric comprises one filling warp yarn 101, 103, 105 or 107 and two binding warp yarns 102 and 102′, 104 and 104′, 106 and 106′, 108 and 108′. Layers with double binding warp yarns could also be used in the first embodiment and layers with single binding warp yarns could be used in this embodiment.
Moreover, the pile warp yarns 501 and 502 are also W-inwoven in the outer or back layers BL2 and BL4 and cross, from one back layer to the other, at the same picks as the connecting warp yarns go from one layer to the other in one fabric. In other words, the change of layer for a connecting warp yarn 401-404 or a pile yarn 501, 502 takes place simultaneously during the weaving method, so that the connecting warp yarns and the pile yarns extend in the same zone in the volume within each distance fabric 42 and 44.
As in the first embodiment, an electronic control unit drives some servomotors in order to determine, for each pick and for each connecting warp yarn and each pile warp yarn, in which layer this warp yarn has been interlaced in the previous pick. On this basis, and on the basis of the shedding pattern to be followed, the electronic control unit selects, amongst several predetermined positions, a position to be taken by a heddle frame driving the warp yarn.
In this embodiment, the number of layers M equals four, whereas the number of weft insertion means equals four, so that the total number of positions which can be taken by each heddle frame is 4×(4+1)=20 if the controlled warp yarn has to be interlaced in the four layers.
The invention makes it easy to weave sophisticated “three dimensional structures” by simplifying the management of the shedding means. The user simply has to program reference positions whose number depend on how many layers the warp yarn is interlaced in and how many insertion means are necessary to weave those layers. The electronic control unit analyses for each pick the pattern and the origin layer to determine the right reference position to join. The reference positions can be stored in the form of absolute positions or in the form of offsets. Since they depend on geometrical parameters as the distances between layers, the user can change the shed geometry and the pattern independently.
Thanks to electric shedding element which can be programmed to move yarns in every position, unsymmetrical weaving can be achieved. For example, the distances between each inner and outer layers can be different between top and bottom fabrics 42 and 44.
In the examples, the electronic control unit determines for each pick in which layer the warp yarn was previously interlaced. This information could be computed externally by a CAD system from the pattern and stored in memory 54 in the same way as the pattern.
In the same way, a CAD system can entirely compute the right position of the shedding means for each pick. The CAD system provides a file of a succession of reference positions which will be stored in the memory 54 of the electronic control unit 50. In such a case, the CAD system forms a computation means, connected or associated to loom 2 and which selects, for each pick, for each connecting warp yarn and each pile warp yarn and amongst several predetermined positions, a position to be taken by the shedding elements, on the basis of some information relating to the layer in which this warp yarn has been interlaced in the previous pick and on the basis of the shedding pattern. The CAD system fulfills a function similar to microchip 52 mentioned for the first embodiment of the invention.
The invention has been described here-above in the case where warp yarns are moved by heddle frames. It is also possible that some or all warp yarns, in particular pile warp yarns and connecting warp yarns, be connected to harness cords driven by respective servomotors such as disclosed in EP-A-0 933 466.
Number | Date | Country | Kind |
---|---|---|---|
09160163.3 | May 2009 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/FR2010/056386 | 5/10/2010 | WO | 00 | 11/8/2011 |