EP3165645B1

EP3165645B1 - Method for weaving pile fabrics and pile fabric with shadow cut pile zones

Info

Publication number: EP3165645B1
Application number: EP15193183.9A
Authority: EP
Inventors: Carl-Günther CORDES; Bert Pols
Original assignee: STAUBLI BAYREUTH GmbH
Current assignee: STAUBLI BAYREUTH GmbH
Priority date: 2015-11-05
Filing date: 2015-11-05
Publication date: 2021-09-01
Anticipated expiration: 2035-11-05
Also published as: CN106987980B; CN106987980A; EP3165645A1

Description

TECHNICAL FIELD OF THE INVENTION

This invention relates to a method for simultaneously weaving two pile fabrics with shadow cut pile zones on a face-to-face weaving machine. This invention also relates to a pile fabric with shadow cut pile zones, which can be woven with such a method.

BACKGROUND OF THE INVENTION

In the field of carpet weaving on face-to-face looms, it is known, e.g. from DE-C-319 324 , to obtain two different orientations of the pile legs, thanks to a variation of the structure of the backing fabrics of two carpets. Weft yarns are bound in the backing fabrics on two different levels: inner weft yarns are inserted on the pile side of the tension warp yarns and back weft yarns are inserted on the other side of the tension warp yarns. Each opening of the binding warp yarns includes only one weft yarn. Considering the bottom fabric shown on the figures of this German patent, a pile leg slants to the right side if it burls around an inner weft yarn which immediately follows another inner weft yarn or if it burls around a back weft yarn which follows two inner weft yarns. A change in the slanting direction of the pile yarns requires a modification of the ground binding. In a standard carpet weaving loom, the binding warp yarns are driven by a cam machine or a dobby. With such a configuration, it is not possible to create bi-dimensional patterns with pile yarns with different slanting direction along the weft direction. In other words, with this method, the pile legs orientation can only be changed on the whole width of a fabric, by varying the backing fabric weave structure, which creates strips of differently oriented piles, but no freely designed shadow effect zone.
EP-A-2894244 solves this problem with a method where a shadow effect results from the way patterning pile yarns are bound in a backing fabric. Since patterning warp yarns are driven by a Jacquard machine, a fabric with various patterns, such as flowers, can be obtained. This method is globally satisfactory. However, the slanting effect obtained with some kinds of warp yarns might be not significant enough to provide a clear shadow effect.
EP-A-1 251 195 discloses a method for a face-to-face weaving of shadow velours. For the embodiment of figure 19, no information is provided with respect to the interaction between the weft yarns and some non-represented binding warp yarns.
EP-A-1 059 374 discloses a Jacquard shadow velour and a method for manufacturing such a fabric where some weft yarns, distributed on either sides of a tension warp yarn, guide some pile yarns according to different patterns. Only some weft yarns are bound to the filing warp yarns in one reed dent, which might be problematic to hold the weft yarns in position within the fabric. Each pile warp yarn follows only one type of path with respect to the corresponding weft yarns.
WO-A-2014/108228 discloses a carpet having a shadow effect and a method for weaving such a carpet where weft yarns can be inserted on three levels into carpet fabrics. Here again, each pile warp yarn follows only one type of path with respect to the corresponding weft yarns.

SUMMARY OF THE INVENTION

This invention aims at solving this problem with a new method for simultaneously weaving two pile fabrics including shadow cut pile zones clearly visible and adjustable both in the warp direction and in the weft direction of the fabric.
To this end, the invention relates to a method for simultaneously weaving two pile fabrics with shadow cut pile zones on a face-to-face weaving machine, wherein an upper backing fabric and a lower backing fabric are woven one above the other with at least one filling warp yarn, at least one binding warp yarn, weft yarns inserted in successive weft insertion cycles between binding warp yarns and filling warp yarns, the weft yarns comprising inner weft yarns, which are inserted on a pile side of the filling warp yarns, and back weft yarns, which are inserted on a back side of the filling warp yarns, opposite to the piles of the fabric. In this method patterning pile yarns are interlaced in the upper backing fabric and in the lower backing fabric, each patterning pile yarn turning externally around an inner and a back weft yarns in each backing fabric. According to the invention, weft yarn groups, made of an inner weft yarn, a back weft yarn and another inner weft yarn, are inserted in at least one backing fabric, in successive weft insertion cycles, and at least one patterning pile yarn follows a path where:

in a first series of weft insertion cycles and at least in a first backing fabric, the patterning pile yarn turns externally around a first inner weft yarn, then internally around a second consecutive inner weft yarn before it turns externally around a consecutive back weft yarn and
in a second series of weft insertion cycles and at least in the first backing fabric, the patterning pile yarn turns externally around a back weft yarn before it turns internally around a first consecutive inner weft yarn and externally around a second consecutive inner weft yarn.

A first and a second weft yarns are consecutive in a backing fabric when, in a warp direction, these first and second weft yarns extend next to each other, with no other weft yarn located between these two weft yarns. With respect to a backing fabric, a consecutive second weft yarn is a weft yarn which is next, in the warp direction, with respect to a first or reference weft yarn. Moreover, two binding warp yarns are used to bind all weft yarns to the filling warp yarns in at least one backing fabric and all weft yarns of a weft yarn group are inserted in a single opening defined by the binding warp yarns.
Owing to the invention, the slanting direction of one pile yarn can be changed when passing from the first series of weft insertion cycles to the second series of weft insertion cycles, as in EP-A-2894244 . This allows weaving a carpet with shadow zones in which the pile yarns directions can vary along the warp direction and along the weft direction. Moreover, the path of the patterning warp yarn in the first series of weft insertion cycles, where this warp yarn turns externally around an inner weft yarn, then internally around another inner weft yarn, then externally around a back weft yarn, allows obtaining a more noticeable slanting effect of the pile tufts once they have been beaten by the reed and cut. This can be obtained with many kinds of warp yarns. The same applies for the patterning weft yarns in the second series of weft insertion cycles, which are slanted in the opposite direction. In other words, the path of the pile yarn in the first series of weft insertion cycles and in the second series of weft insertion cycles allows a better differentiation of the slanting orientations of the pile tufts. Since each weft yarn group is inserted in a single opening defined by the binding warp yarns, all weft yarns are firmly held in position within the backing fabrics and pressed together by the binding warp yarns when they are pulled to close these openings.
In the meaning of the present description, the expression « turns externally » means that a pile yarn "turns", "winds" or "burls" around a weft yarn, which belongs to a backing fabric, on a side of this weft yarn which is oriented opposite to the backing fabric of the other pile fabric simultaneously woven with the one to which the weft yarn belongs. In other words, the pile yarn "turns", "winds" or "burls" around a weft yarn, which belongs to a backing fabric, on a side of this weft yarn which is oriented opposite to the pile legs which protrude from the backing fabric. And the expression "turns internally" means that a pile yarn "turns", "winds" or "burls" around a weft yarn, which belongs to a backing fabric, on a side of this weft yarn which is oriented towards the backing fabric of the other pile fabric. In other words, the pile yarn "turns", "winds" or "burls" around a weft yarn, which belongs to a backing fabric, on a side of this weft yarn which is oriented towards the pile legs which protrude from the backing fabric.
According to advantageous but optional aspects of the invention, such a weaving method may incorporate one or several of the following features, considered in any technically allowable combination:

In the first series of weft insertion cycles, the patterning pile yarn follows at least twice a path where it turns externally around a first inner weft yarn, then internally around a second consecutive inner weft yarn before it turns externally around a consecutive back weft yarn and, in the second series of weft insertion cycles, the patterning pile yarn follows at least twice a path where it turns externally around a back weft yarn before it turns internally around a first consecutive inner weft yarn and externally around a second inner weft yarn.
The binding warp yarns follow a six pick pattern.
The patterning warp yarn follows a path where in the first series of weft insertion cycles and in both backing fabrics, the patterning pile yarn turns externally around a first inner weft yarn, then internally around a second consecutive inner weft yarn before it turns externally around a consecutive back weft yarn and, in the second series of weft insertion cycles and in both backing fabrics, the patterning pile yarn turns externally around a back weft yarn before it turns internally around a first consecutive inner weft yarn and externally around a second inner weft yarn.
Two patterning pile yarns are used during the first and/or second series of weft insertion cycles.
The two patterning weft yarns follow, in the two baking fabrics, paths that are symmetric with respect to a median plane.
The patterning warp yarn follows a path which has different first and second series of weft insertion cycles in the upper backing fabric and in the lower backing fabric.
The backing fabric weave structure, which is defined as the sequence of the consecutive positions of the binding warp yarn and the filling warp yarn in the shed, repeats and remains the same in the first and second series of weft insertion cycles

This invention also relates to a pile fabric with shadow cut pile zones, this fabric comprising a backing fabric woven with yarn sets including at least one filling warp yarn, at least one binding warp yarn and weft yarns located between the binding warp yarn and the filling warp yarn, the weft yarns comprising inner weft yarns which are located on a pile side of the filling warp yarn and back weft yarns which are located on a back side of the filling warp yarn, opposite the piles of the fabric. This fabric also includes pile tufts corresponding each to a patterning pile yarn, belonging to a yarn set, interlaced in the backing fabric and forming two pile legs. Weft yarn groups are made of an inner weft yarn, a consecutive back weft yarn and another consecutive inner weft yarn and for at least one yarn set, at least a first pile tuft and a second pile tufts, which are offset with respect to each other in a warp direction of the fabric, are interlaced in the backing fabric in a configuration where:

in the warp direction, the first pile tuft turns externally around a first inner weft yarn, then internally around a second consecutive inner weft yarn before it turns externally around a consecutive back weft yarn and
in the warp direction, the second pile tuft externally around a back weft yarn before it turns internally around a first consecutive inner weft yarn and externally around a second consecutive inner weft yarn.

According to the invention, the pile fabric includes two binding warp yarns used to bind the weft yarns to the filling warp yarn and the patterning pile yarn of a yarn set whereas all weft yarns of a weft yarn group go through an opening formed by the two binding warp yarns.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood and other advantages thereof will appear more clearly upon reading the following description of several embodiments of a weaving method and a fabric according to its principle, provided solely as an example and made in reference to the appended drawings, in which:

figure 1 is a schematic cross section along the warp direction of two pile fabrics which are woven on a face-to-face weaving machine, this cross-section representing a first weaving method according to the invention,
figure 2 is a front view of a carpet woven with the method represented on figure 1, this carpet being also according to the invention,
figures 3 and 4 are schematic views, similar to figure 1, for a second weaving method and a third weaving method, this third weaving method being also according to the invention.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

Figure 1 is a schematic cross-section, in the warp direction, of two carpets C1 and C2 simultaneously woven one above the other on a face-to-face weaving machine or loom, with two non represented insertion means.
Picks P1 to P32 are represented on figure 1 and define insertion cycles for weft yarns.
Each carpet C1 or C2 includes a backing fabric F1, respectively F2, and piles D1, respectively D2, extending from one backing fabric F1 or F2 towards the other backing fabric. Backing fabrics F1 and F2 might also be called ground fabrics. Piles D1 and D2 are supposed to be separated from each other by a knife K belonging to a not further represented cutting device. Knife K travels along a median plane π0 of weaving machine on which carpets C1 and C2 are being woven. Plane π0 extends parallel to and between backing fabrics and F1 and F2. It is equidistant from these two fabrics.
Backing fabric F1 includes two binding warp yarns b1 and b1' and a filling warp yarn f1. Backing fabric F2 includes two binding warp yarn, b2 and b2' and a filling warp yarn f2. Alternatively, several filling warp yarns can be used in one or each backing.
The warp yarns also include pile warp yarns which can extend from one backing fabric to the other, in order to form piles D1 and D2, as represented by pile warp yarn PY on figure 1. Other pile warp yarns I, II and III constitute dead pile yarns which remain in baking fabric F1. Similarly, dead pile yarns VI, VII and VIII remain in backing fabric F2.
Binding warp yarns b1 and b1' and filling warp yarn f1 together form a group of warp yarn devoted to backing fabric F1. Similarly, binding warp yarns b2 and b2' and filling warp yarn f2 together form a group of warp yarns devoted to backing fabric F2. Binding warp yarns and filling warp yarns are drawn in through heddles which are mounted in heddle frames connected to a non represented shedding device, such as a dobby or a cam machine. Pile warp yarns I to III, PY and VI to VIII are fed from a creel and drawn in through heddles connected to a non-represented Jacquard machine.
A top shed is defined between some warp yarns placed by their respective heddles into a top position and a middle position. A bottom shed is defined between some warp yarns placed by their respective heddles into a middle position and a bottom position.
Binding warp yarns, filling warp yarns and pile yarns are grouped into sets which extend side by side in the weft direction, that is in a direction perpendicular to the plane of figure 1. This direction is represented on figure 2 with arrow DE, whereas arrow DA represents a warp direction perpendicular to weft direction DE. Warp direction DA is also represented on figure 1. Directions DA and DE oriented. In particular, direction DA goes from pick P1 towards pick P32.
All the warp yarns of one set go through the same reed dent space of a non-represented reed of the weaving machine. All the warp yarns represented on figure 1, that is binding warp yarns b1, b1', b2 and b2', filling warp yarns f1 and f2 and pile warp yarns I to II, III, PY and VI to VIII belong to the same set of warp yarns.
At each pick P1 to P32, one weft yarn is inserted into backing fabric F1 and one weft yarn is inserted into backing fabric F2 by two non represented insertion means which travel into the top and bottom sheds. This insertion means can include rapiers or any similar device.
Weft yarns include inner weft yarns Wi which can also be called "front" weft yarns, since they are oriented, with respect to backing fabric F1 or F2, towards the front of carpet C1 or C2, that is towards median plane π0. Weft yarns also include back weft yarns Wb which can also be called "outer" weft yarns, since they are oriented towards the outside of a space defined between backing fabrics F1 and F2 in the configuration of figure 1. Inner weft yarns Wi are located, in each backing fabric on the same side as the piles D1 or D2 with respect to the filling warp yarn f1 or f2. Back weft yarns Wb are located, in each backing fabric F1 or F2, opposite the piles D1 and D2 with respect to the filling warp yarn f1 or f2.
At pick P1, two outer weft yarns Wb are simultaneously inserted into top backing fabric F1 and into bottom backing fabric F2. In top backing fabric F1, the shedding device, such as the dobby and Jacquard machine mentioned here-above, places binding warp yarn b1 and patterning warp yarn PY in the top position, whereas the other binding warp yarn b1', filing warp yarn f1 and dead pile yarns I to III are placed in the middle position. In bottom backing fabric F2, binding warp yarn b2, filling warp yarn f2 and dead pile yarns VI to VIII are placed in the middle position, whereas the other binding warp yarn b2' is placed in the bottom position.
At pick P2, two inner weft yarns Wi are simultaneously inserted into top backing fabric F1 and into bottom backing fabric F2. In top backing fabric F1, binding warp yarn b1, filling warp yarn f1 and dead pile yarns I to III are placed in the top position, whereas binding warp yarn b1' is placed in the middle position. In bottom backing fabric F2, binding warp yarn b2 is placed in the middle position, whereas binding warp yarn b2', filling warp yarn f2, patterning pile yarn PY and dead pile yarns VI to VIII are placed in the bottom position.
At pick P3, two inner weft yarns Wi are simultaneously inserted into top backing fabric F1 and into bottom backing fabric F2. In top backing fabric F1, binding warp yarn b1', filling warp yarn f1 and dead pile yarns I to III are placed in the top position, whereas binding warp yarn b1 is placed in the middle position. In bottom backing fabric F2, binding warp yarn b2' and patterning pile yarn PY are placed in the middle position, whereas binding warp yarn b2, filling warp yarn f2 and dead pile yarns VI to VIII are placed in the bottom position.
At pick P4, two outer weft yarns Wb are simultaneously inserted into top backing fabric F1 and into bottom backing fabric F2. In top backing fabric F1, binding warp yarn b1' is placed in the top position, whereas binding warp yarn b1, filling warp yarn f1 and dead pile yarns I to III are placed in the middle position. In bottom backing fabric F2, binding warp yarn b2', filling warp yarn f2 and dead pile yarns VI to VIII are placed in the middle position, whereas binding warp yarn b2 and patterning pile yarn PY are placed in the bottom position.
At pick P5, two inner weft yarns Wi are simultaneously inserted into top backing fabric F1 and into bottom backing fabric F2. In top backing fabric F1, binding warp yarn b1', filling warp yarn f1, patterning pile yarn PY and dead pile yarns I to III are placed in the top position, whereas binding warp yarn b1 is placed in the middle position. In bottom backing fabric F2, binding warp yarn b2' is placed in the middle position, whereas binding warp yarn b2, filling warp yarn f2 and dead pile yarns VI to VIII are placed in the bottom position.
At pick P6, two inner weft yarns Wi are simultaneously inserted into top backing fabric F1 and into bottom backing fabric F2. In top backing fabric F1, binding warp yarn b1, filling warp yarn f1 and dead pile yarns I to III are placed in the top position, whereas binding warp yarn b1' and patterning pile yarn PY are placed in the middle position. In bottom backing fabric F2, binding warp yarn b2 is placed in the middle position, whereas binding warp yarn b2', filling warp yarn f2 and dead pile yarns VI to VIII are placed in the bottom position.
A pick sequence is defined by picks P1 to P6 and this sequence is repeated for picks P7 to P12 and starts again with pick p13. A first series of weft insertion cycles is formed by picks P1 to P13. In this first series of weft insertion cycles, each pick where two outer weft yarns Wb are inserted into backing fabrics F1 and F2 is followed by two picks where tow inner weft yarns Wi are inserted into these fabrics.
In the first series of weft insertion cycles, patterning pile yarn PY follows a three pick binding path within each backing fabric F1 or F2. More precisely, patterning pile yarn PY turns externally around a first inner weft yarn Wi of backing fabric F1, at picks P5 and P11, before it turns internally around a second consecutive inner weft yarn Wi, at picks P6 and P12. Then, patterning pile yarn PY turns externally around a back weft yarn Wb of backing fabric F1, at picks P7 and P113. Similarly, in backing fabric F2, patterning pile yarn PY turns externally around a first inner weft yarn Wi, at picks P2 and P8, prior to turning internally around a second consecutive inner weft yarn Wi, at picks P3 and P9, and then turning externally around a back weft yarn Wb, at picks P4 and P10. In each backing fabric F1 or F2, once it has turned around the back weft yarn Wb, patterning warp yarn PY leaves the backing fabric where it has been previously turning around two inner weft yarns Wi and crosses the empty space between backing fabrics F1 and F2 in order to enter the other backing fabric, as shown, for example, between picks P4 and P5 or between picks P7 and P8.
During picks P1 to P13, patterning pile yarn PY forms successive loops which includes two legs that will form pile D1 or D2 once cut by knife K. Along direction DA, each loop, formed by patterning pile yarn PY during picks P1 to P13, successively goes around one inner weft yarn Wi, on the outer or external side of this weft yarn, around another inner weft yarn Wi, on the inner or internal side of this weft yarn, and around one back weft yarn Wb, on the outer or external side of this weft yarn.
Six picks are necessary to form two pile legs in each backing fabric F1 and F2. This number of picks also defines the length of the pick sequence which is repeated between picks P1 and P13 by the binding warp yarns and the filling warp yarns, as explained here-above. In other words, the Backing Fabric Weave Repeat or "BFWR" equals six.
In picks P14 to P32, binding warp yarns b1, b1', b2, b2', filling warp yarns f1 and f2, dead pile yarns I to III and VI to VIII continue to pattern alike in picks P1 to P13. This is an important feature of the method of the invention, in so far as the ground binding or weave used for backing fabrics F1 and F2 does not change during weaving. Weft yarns Wi and Wb are also inserted as in the first series of insertion cycles. In particular, each pick where two outer weft yarns Wb are inserted into backing fabrics F1 and F2 is followed by two picks where two inner weft yarns Wi are inserted into these fabrics.
Picks P14 to P18 together constitute a transition series of weft insertion cycles where patterning weft yarn PY follows a V shaped binding in each backing fabric F1 or F2.
Picks P19 to P32 together form a second series of weft insertion cycles. At pick P19, patterning yarn PY starts again to follow a three picks binding path in each backing fabric, with a path different from the one used in picks P1 to P13. As from pick P19 and up to pick P32, patterning yarn PY turns first around a back weft yarn Wb, then internally around a first consecutive inner weft yarn Wi and then externally around a second consecutive inner weft yarn, in three consecutive picks, as shown by picks P19 to P21 in top backing fabric F1 and by picks P22 to P24 in bottom backing fabric F2. In each backing fabric F1 or F2, once it has turned around the second consecutive inner weft yarn Wi, patterning warp yarn PY leaves the backing fabric where it has been previously turning around the outer weft yarn Wb and the first inner weft yarns Wi and crosses the empty space between backing fabrics F1 and F2 in order to enter the other backing fabric, as shown, for example, between picks P21 and P22 or between picks P24 and P25.
As mentioned here above, in the second series of weft insertion cycles, the ground binding remains as in picks P1 to P13. The repartition of the warp yarns at pick P19 is the same as at pick P1.
Because of the change of binding path of the patterning pile yarn PY between the first series of picks P1 to P13 and the second series of picks P19 to P32, the piles D1 and D2 formed by patterning pile yarn PY take two different slanting orientations once fabrics F1 and F2 have been beaten by the reed and separated from each other by knife K.
One considers pile tufts formed by patterning pile yarn PY once carpets C1 and C2 have been separated by knife K. A portion PY.1 of yarn PY, which has been woven in backing fabric F2 between picks P10 and P11, forms a tuft or loop with two piles D2 slanted in the direction of arrows A1. Actually, portion PY.1 is a patterning individual pile tuft of carpet C2 which, along warp direction DA turns externally around inner weft yarn Wi inserted at pick P8, then internally around inner weft yarn Wi inserted at pick P9 before it turns around back weft yarn Wb inserted at pick P10. Similarly, a portion PY.2 of yarn PY, which has been woven in backing fabric F2 at picks P22 to P24, forms a tuft or loop with two piles slanted in the direction of arrows A2. Portion PY.2 is a patterning individual pile tuft of carpet C2 which, along warp direction DA, turns externally around back weft yarn Wb inserted at pick P22 before it turns internally around inner weft yarn Wi inserted at pick P23 and the externally around inner weft yarn Wi inserted at pick P24.
Pile tufts PY.1 and PY.2 are offset with respect to each other along warp direction DA.
Thus, by modifying the path of patterning pile yarn PY between the first series of insertion cycles, defined by picks P1 to P13, and the second series of insertion cycles, defined by picks P19 to P32, two slanting orientations of the piles D1 and D2 can be obtained, offset along warp direction DA, for pile tufts PY.1 and PY.2.
This change of the slanting orientation of the piles D1 and D2 is obtained without changing the weave patterns of the binding warp yarns b1 and of the filling warp yarns f1 and f2, which remain the same between picks P1 and P32. In other words, the backing fabric ground weave structure remains the same for each backing fabric F1 and F2, for all picks. In particular, the BFWR remains equal to six.
The change of the slanting orientation of piles D1 and D2 along warp direction DA can be obtained by individually driving patterning pile yarn PY via the Jacquard mechanism, which means that adjacent pile yarns in the weft direction DE can have different configurations and switch from a first slanting orientation to a second slanting orientation at different locations along the warp direction DA.
It is thus possible to make, via different slanting orientations of the piles D2 of carpet C2 represented on figure 2, a bi-dimensional pattern P, which is formed in a shadow cut pile zone Z and represents a flower in the example. Because of the specific binding path used at picks P1 to P13, slanting of piles D1 and D2 in the direction of arrows A1 is more important than with the method of EP-A-2894244 , which makes it easier to weave a noticeable flower pattern, even with relatively matt pile yarns.
This can be combined with a change of patterning warp yarn, by using one of yarns I to III or VI to VIII instead of pile PY for creating piles of different colors or aspects in different zones of carpets C1 and C2.
In the method of figure 1, patterning pile yarn PY follows a path where, in each backing fabric F1 and F2, the binding path of picks P5 to P7 in backing fabric F1 or the binding path of picks P2 to P4 in backing fabric F2 is implemented twice before the slanting direction of the piles D1 and D2 is changed. Similarly, the binding path of patterning pile yarn PY is repeated twice in each backing fabric as from pick 19. In practice, in order for the change in the slanting direction or orientation of the piles to be easily visible, the patterning pile yarn PY follows such a patterning path twice or more in each backing fabric, both during the first series of weft insertion cycles and during the second series of weft insertion cycles. When carpets C1 and C2 are separated by cutting the piles, in each carpet, at least four consecutive pile tufts PY.1 turn externally around a first inner weft yarn Wi prior to turning internally around a second inner weft yarn and to turning externally around a consecutive back weft yarn Wb. These pile tufts PY.1 are followed, after transition zone corresponding to picks 14 to 18, by at least four consecutive pile tufts PY.2 which turn externally around a back weft yarn Wb prior to internally turning around a first consecutive inner weft yarn, then externally around a second consecutive inner weft yarn Wi.
In this first method, a weft yarn group can be defined by three weft yarns successively introduced within one backing fabric F1 or F2 during three successive picks. For all picks P1 to P32, in backing fabric F1, successive weft yarn groups G1 are formed, which include an inner weft yarn Wi, an outer weft yarn Wb and another inner weft yarn Wi, inserted consecutively, in this order, within the shed. For instance, a group G1 is formed by weft yarns inserted into the top shed during picks P3 to P5 or during picks P21 to P23. Similarly, in fabric F2, successive weft yarn groups G2 are formed, which include an inner weft yarn Wi, an outer weft yarn Wb and another inner weft yarn Wi, inserted consecutively, in this order, within the shed. For instance, a group G2 is formed by weft yarns inserted into the bottom shed during picks P3 to P5 or during picks P21 to P23.
On the other hand, in fabric F1, binding warp yarns b1 and b1' define between them a series of openings O1. For instance, an opening O1 is defined between binding warp yarns b1 and b1' at picks 3 to 5 or at picks 6 to 8. Similarly, in backing fabric F2, binding warp yarns b2 and b2' define between them a series of openings O2. For instance, an opening O2 is defined between binding warp yarns b2 and b2' at picks 3 to 5 or at picks 6 to 8.
Each weft yarn group G1 is inserted in a single opening O1 and each group G2 is inserted in a single opening O2. Thus all weft yarns are firmly held in position within backing fabrics F1 and F2. Moreover, when binding warp yarns b1 and b1' or b2 and b2' are pulled to close openings O1 or O2, they press weft yarns of a group G1 or G2 together. If one considers weft yarns of groups G1 and G2 corresponding to picks P6 to P8, then inner weft yarns Wi inserted at pick P8 are pressed against tufts PY.1 formed between picks P7 and P8, at a location along these tufts closer to median plane π0 than back weft yarns Wb of pick P7. This forces pile tufts PY.1 to slant in the direction of arrows A1. The tighter the closure of openings O1 and O2, the higher the slanting effect. In the first series of weft insertion cycles, the slanting effect is obtained by inner weft yarn Wi inserted at pick PN acting on pile tuft PY.1 formed between picks PN-1 and PN, for N equal to 2, 5, 8 and 11. In the second series of weft insertion cycles, the slanting effect is obtained by inner weft yarn Wi inserted at pick PN acting on pile tufts PY.2 formed between picks PN and PN+1, for N equal to 21, 24, 27 and 30.
In the second and third methods of the invention represented on figures 3 and 4, the same elements as in the first embodiment have the same references. Unless otherwise specified, the method of one of figures 3 and 4, works in the same way as the method of figure 1.
The face-to-face weaving machine used with these methods also has two non represented insertion means, a first shedding device, for instance a dobby, which can move the binding and filling warp yarns between two positions, and a second shedding device, for instance a Jacquard mechanism, which can move the pile yarns between three positions.
In the second method represented on figure 3 which does not belong to the invention, the patterning weft yarn PY follows the same path as in the first embodiment.
In this method, the ground weave structure is changed in order to achieve a greater density in the warp direction DA. More precisely, one defines a set of warp yarn as in the first method and, for such a set of warp yarns, the binding pile yarns b1, b1', b2 and b2' follow a path where they bind together only some of the weft yarns Wi and Wb with the filing warp yarns f1 or f2. In the example of figure 3, between picks P1 and P13, only warp yarns Wi and Wb inserted at picks P1, P2, P4, P7 and P9-P14 are bound to backing fabric F1. Warp yarns Wi inserted at picks P3, P5, P6 and P8 are bound to backing fabric F1 in the adjacent set of warp yarns, that is in the set of warp yarns going through a reed dent adjacent to the one through which the warp yarns visible on figure 3 go through. This also applies for the transition series P14 to P18 and for the second series of weft insertion cycles P19 to P32.
Similarly, with the set of warp yarns visible on figure 3, only some inner weft yarns are bound to the filing warp yarns in backing fabric F2. This applies for the first series of weft insertion cycles P1-P13, for the transition series P14 to P18 and for the second series of weft insertion cycles P19 to P32.
For the set of warp yarns visible on figure 3, the binding warp yarns follow a pattern which defines openings O1', O1", O2' and O2". Openings O1' and O2' each include one back weft yarn Wb, the inner weft yarn Wi inserted immediately before this back weft yarn and the inner weft yarn Wi inserted immediately after. Openings O1" and O2" each include one back weft yarn Wb, exclusive of inner weft yarns. Thus, binding warp yarns tie all outer weft yarns Wb and half of the inner weft yarns Wi to the filling warp yarns f1 and f2. For a set of warp yarns going through an adjacent reed dent which is not represented, the binding warp yarns follow a pattern which ties all outer weft yarns Wb and the other half of the inner weft yarns Wi to the filling warp yarns f1 and f2.
As in the first embodiment, when openings O1' and O2' are closed by pulling on the binding warp yarns, inner weft yarns Wi inserted in such openings act on back weft yarns inserted in the same opening in order to push tufts PY.1 and PY.2 respectively in the direction of arrows A1 or in the direction of arrows A2. Some tufts PY.1 and PY.2 turn around back weft yarns Wb inserted in openings O1'' or O2", as back weft yarns inserted at picks P4, P7 and P28. The adjacent inner weft yarns Wi inserted at picks P5, P8 and P27 go through openings O1' and O2' for adjacent sets of warp yarns, so that they are also drawn towards these back weft yarns when one pulls on binding warp yarns of the adjacent sets of warp yarns. Thus, an efficient slanting effect is obtained on all tufts in zones corresponding to picks P1 to P13 and P19 to P32.
In this embodiment also, the ground binding pattern of weft yarns Wi and Wb with warp yarns b1, b1', b2, b2', f1 and f2 remains the same for all picks.
In this embodiment, the Backing Fabric Weave Repeat or "BFWR" equals twelve, with a 6 pick offset between adjacent sets of warp yarns.
In the third method represented on figure 4 which belongs to the invention, weft yarns are bound in the backing fabrics F1 and F2, binding warp yarns b1, b1', b2, b2', filling warp yarns f1, f2 and dead pile yarns I-III and VI-VIII follow the same binding path as in the first embodiment. Inner and outer weft yarns Wi and Wb are inserted into the sheds as in the first embodiment.
First and second patterning pile yarns PY and QY are used. Patterning pile yarn PY follows the same binding path as patterning pile yarn PY in the first two embodiments, but for pick 15 where it remains in bottom backing fabric F2 and turns internally around an inner weft yarn Wi. In other words, in the method of figure 4, the first series of weft insertion cycles includes picks P1 to P16 and the transition series includes picks P17 and P18.
When first patterning pile yarn PY is in first backing fabric F1, second patterning pile yarn QY is in the second backing fabric F2 and vice-versa. Actually, second patterning pile yarn QY follows a path symmetrical to the path of first patterning pile yarn PY with respect to plane π0.
The BFWR of this method equals six, as in the first embodiment.
Patterning pile yarns PY and QY are slanted in the same direction in a zone of carpets C1 and C2 corresponding to the first and second series of weft insertion cycles, that is between picks P1 and P13, and in a zone of carpets C1 and C2 corresponding to the second series of weft insertion cycles, that is between picks P19 and P32. In other words, pile tufts PY.1 and QY.1 obtained in a zone of carpets C1 and C2 corresponding to the first series of weft insertion cycles P1 to P16 are slanted in the direction of arrows A1, whereas pile tufts PY.2 and QY.2 obtained in a zone of these carpets corresponding to the second series of weft insertion cycles P18 to P32 are slanted in the direction of arrows A2.
As in the first method, closing of openings O1 and O2 results in some inner weft yarns Wi being firmly pressed against the adjacent pile tufts PY.1 or PY.2.
This method provides an increased tuft density along the weft direction DE.
Alternatively, pile tufts PY.1 and QY.1 or PY.2 and QY.2 can be slanted in opposite directions in at least one of the zones mentioned here-above.
Two patterning pile yarns can be used only during the first series of insertion cycles or only during the second series of insertion cycles. Moreover, two patterning pile yarns can be used for some sets of warp yarns only.
According to a variant of the invention applicable to all embodiments, one uses different series of first and second weft insertion cycles for the two carpets C1 and C2, that is in top and bottom backing fabrics F1 and F2.
The invention requires filling warp yarns or tension warp yarns which are more tensioned that binding warp yarns, so that inner weft yarns and back weft yarns are on two different levels in the backing fabric. The methods are independent of the characteristics such as material, color, thickness and count of weft yarns which are used. The same kind of weft yarn can be used for the back weft yarns and the inner weft yarns.
In all embodiments, the backing fabrics F1 and F2 incorporate dead pile yarns I-III, and VI-VIII. This is however not compulsory.
The invention is represented in the figures when patterning pile yarn PY or QY follows a three picks binding path in both backing fabrics F1 and F2. Alternatively, such a three picks binding path can be followed by the patterning pile yarn in one only of the backing fabrics.
The invention is not limited to a face-to-face weaving machine with two insertion means and could apply to a face-to-face weaving machine with three or more insertion means which insert simultaneously two weft yarns into the backing fabrics.
The technical features of the embodiments and alternative embodiments considered here-above can be combined in order to generate new embodiments of the invention.

Claims

Method for simultaneously weaving two pile fabrics (C1, C2) with shadow cut pile zones (Z) on a face-to-face weaving machine, wherein:
- an upper backing fabric (F1) and a lower backing fabric (F2) are woven one above the other with:
- at least one filling warp yarns (f1, f2),

- at least one binding warp yarn (b1, b1', b2, b2'),

- weft yarns (Wi, Wb) inserted in successive weft insertion cycles (P1-P32) between binding warp yarns and filling warp yarns, the weft yarns comprising inner weft yarns (Wi), which are inserted on a pile side of the filling warp yarns, and back weft yarns (Wb), which are inserted on a back side of the filling warp yarns, opposite to the piles (D1, D2) of the fabric,

- patterning pile yarns (PY; PY, QY) are interlaced in the upper backing fabric (F1) and in the lower backing fabric (F2), each patterning pile yarn turning externally around an inner and a back weft yarns (Wi, Wb) in each backing fabric,

- weft yarn groups (G1, G2), made of an inner weft yarn (Wi), a back weft yarn (Wb) and another inner weft yarn (Wi), are inserted in at least one backing fabric (F1, F2), in successive weft insertion cycles, and

- at least one patterning pile yarn (PY; PY, QY) follows a path where:
- in a first series of weft insertion cycles (P1-P13; P1-P16) and at least in a first backing fabric (F1, F2), the patterning pile yarn (PY; PY, QY) turns externally around a first inner weft yarn (Wi), then internally around a second consecutive inner weft yarn (Wi) before it turns externally around a consecutive back weft yarn (Wb) and

- in a second series of weft insertion cycles (P19-P32) and at least in the first backing fabric (F1, F2), the patterning pile yarn (PY; PY, QY) turns externally around a back weft yarn (Wb) before it turns internally around a first consecutive inner weft yarn (Wi) and externally around a second consecutive inner weft yarn (Wi),
characterized in that

- two binding warp yarns (b1, b1', b2, b2') are used to bind all weft yarns (Wi, Wb) to the filling warp yarns (f1, f2) in at least one backing fabric (F, F2) and

- all weft yarns of a weft yarn group (G1, G2) are inserted in a single opening (O1, O2) defined by the binding warp yarns.
A method according to claim 1, characterized in that:
- in the first series of weft insertion cycles (P1-P13; P1-P16), the patterning pile yarn (PY; PY, QY) follows at least twice a path where it turns externally around a first inner weft yarn (Wi), then internally around a second consecutive inner weft yarn (Wi) before it turns externally around a consecutive back weft yarn (Wb) and

- in the second series of weft insertion cycles (P19-P32; P22-P32), the patterning pile yarn (PY; PY, QY) follows at least twice a path where it turns externally around a back weft yarn (Wb) before it turns internally around a first consecutive inner weft yarn (Wi) and externally around a second inner weft yarn (Wi).
A method according to any preceding claim, characterized in that the binding warp yarns (b1, b1', b2, b2') follow a six pick pattern.
A method according to one of the preceding claims, characterized in that the patterning warp yarn follows a path where:
- in the first series of weft insertion cycles (P1-P13; P1-P16;) and in both backing fabrics (F1, F2), the patterning pile yarn (PY; PY, QY) turns externally around a first inner weft yarn (Wi), then internally around a second consecutive inner weft yarn (Wi) before it turns externally around a consecutive back weft yarn (Wb) and

- in the second series of weft insertion cycles (P19-P32) and in both backing fabrics (F1, F2), the patterning pile yarn (PY; PY, QY) turns externally around a back weft yarn (Wb) before it turns internally around a first consecutive inner weft yarn (Wi) and externally around a second inner weft yarn (Wi).
A method according to any preceding claim, characterized in that two patterning pile yarns (PY; QY) are used during the first and/or second series of weft insertion cycles.
A method according to claims 4 and 5, characterized in that the two patterning weft yarns (PY, QY) follow, in the two baking fabrics (F1, F2), paths that are symmetric with respect to a median plane π0.
A method according to any one of claims 1 to 5, characterized in that the patterning warp yarn (PY; PY, QY) follows a path which has different first and second series of weft insertion cycles in the upper backing fabric (F1) and in the lower backing fabric (F2).
A method according to any preceding claim, characterized in that the backing fabric weave structure, which is defined as the sequence of the consecutive positions of the binding warp yarn (b1, b1', b2, b2') and the filling warp yarn (f1, f2) in the shed, repeats and remains the same in the first and second series of weft insertion cycles (P1-P13, P19-P32 ; P1-P16, P19-P32)
A pile fabric (C1, C2) with shadow cut pile zones, this fabric comprising:
- a backing fabric (F1, F2) woven with yarn sets including:
- at least one filling warp yarn (f1, f2),

- at least one binding warp yarn (b1, b1', b2, b2'),

- weft yarns (Wi, Wb) located between the binding warp yarn and the filling warp yarn, the weft yarns comprising inner weft yarns (Wi) which are located on a pile side of the filling warp yarn and back weft yarns (Wb) which are located on a back side of the filling warp yarn, opposite the piles of the fabric,

- pile tufts (PY.1, PY.2; PY.1, PY.2, QY.1, QY.2) corresponding each to a patterning pile yarn (PY; PY, QY), belonging to a yarn set, interlaced in the backing fabric and forming two pile legs,
where

- weft yarn groups (G1, G2) are made of an inner weft yarn (Wi), a consecutive back weft yarn (Wb) and another consecutive inner weft yarn (Wi) and

- for at least one yarn set, at least a first pile tuft (PY.1; PY.1, QY.1) and a second pile tufts (PY.2; PY.2, QY.2), which are offset with respect to each other in a warp direction (DA) of the fabric (F1, F2), are interlaced in the backing fabric in a configuration where:
- in the warp direction, the first pile tuft (PY.1; PY.1, QY.1) turns externally around a first inner weft yarn (Wi), then internally around a second consecutive inner weft yarn (Wi) before it turns externally around a consecutive back weft yarn (Wb) and

- in the warp direction, the second pile tuft (PY.2; PY.2, QY.2) externally around a back weft yarn (Wb) before it turns internally around a first consecutive inner weft yarn (Wi) and externally around a second consecutive inner weft yarn (Wi).

characterized in that the pile fabric includes two binding warp yarns (b1, b1', b2, b2') used to bind the weft yarns (Wi, Wb) to the filling warp yarn (f1, f2) and the patterning pile yarn (PY ; PY, QY) of a yarn set and in that all weft yarns (Wi, Wb) of a weft yarn group (G1, G2) go through an opening (O1, O2) formed by the two binding warp yarns.