Method for face-to-face weaving pile fabrics

With a method for face-to-face weaving pile fabrics, whereby weft threads (1-6) are brought between warp threads (7-12) of a series of warp thread systems so that two backing fabrics (21), (22) are woven located one above the other with tension warp threads (7), (10) and dead pile warp threads (13-20) inwoven in the backing fabrics, whereby pile warp threads (13, 14, 18, 20) in each backing fabric form respective pile loops around first (1), (4) and around second weft threads (2), (5) which respectively run along the back and along the pile side of a tension warp thread (7), (10), and whereby the pile-forming pile warp threads (13, 14, 18, 20) are cut through between the backing fabrics, the dead pile warp threads (13-20), running along the pile side of the second weft threads (2), (5), are inwoven. Because of this the inwoven dead pile warp threads (13-20) are prevented from being pushed through to the back of the fabric by the second weft threads (2), (5), and a latex layer applied to the back can penetrate well to the pile loops which have been formed around these second weft threads (2), (5).

This invention relates to a method for weaving pile fabrics, whereby weft
 threads are brought between warp threads of a series of warp thread
 systems so that two backing fabrics are woven located one above the other,
 and whereby in a number of warp thread systems dead pile warp threads and
 tension warp threads are inwoven in the backing fabrics, and at least one
 pile warp thread is pile-loop-formingly passed around a weft thread
 alternately in the top and the bottom backing fabric, so that in each
 backing fabric respective pile loops are formed around first and second
 weft threads which run respectively along the back and along the pile side
 of a tension warp thread, and whereby the pile-forming pile warp threads
 are cut through between the backing fabrics.
 This invention also relates to pile fabrics which are woven according to
 such a method.
 Carpet weaving on a face-to-face weaving machine according to the above
 described weaving method is known.
 In each warp thread system for each backing fabric a tension warp thread
 and two binding warp threads are provided. The backing fabrics are so
 woven that in each warp thread system alternately along the back and along
 the pile side of the tension warp thread a respective weft thread is
 inwoven by the two binding warp threads. These binding warp threads cross
 each other repeatedly so that in each case between two successive
 crossings they enclose a weft thread running along the back of the tension
 warp thread and a weft thread running along the pile side of the tension
 warp thread.
 Per warp thread system a number of pile warp threads are provided. In order
 to form pile a pile warp thread is passed around a weft thread alternately
 in the top and the bottom backing fabric. This occurs according to a
 one-shot weave so that in each pile fabric a respective pile loop is
 formed around each weft thread. The successive pile loops are therefore
 alternately formed around a weft thread running along the back of the
 tension warp thread and around a weft thread running along the pile side
 of the tension warp thread.
 In this specification and in the claims attached hereto a weft thread
 running along the back of the tension warp thread, around which a pile
 loop is formed, is called "a first weft thread", and a weft thread running
 along the pile side of the tension warp thread, around which a pile loop
 is formed, is called "a second weft thread".
 The non-pile-forming pile warp threads or parts of pile warp threads,
 referred to by the term "dead pile warp threads" in that which follows,
 are inwoven in these backing fabrics divided between the top and the
 bottom backing fabric. These dead pile warp threads therefore come to lie
 next to the tension warp threads, between the successive weft threads.
 The pile-forming pile warp threads are finally cut through between the two
 backing fabrics so that two separate pile fabrics are obtained.
 This weaving method can be utilized on a single rapier weaving machine and
 on a double rapier weaving machine. In the latter case in the course of
 the successive weft insertion cycles alternately the top and the bottom
 weft insertion means is disengaged.
 This weaving method and the fabrics manufactured according to this weaving
 method however have the following disadvantages:
 The second weft threads running along the pile side have the tendency to
 push the inwoven dead pile warp threads through to the back of the carpet.
 Because of this the colors of the inwoven dead pile warp threads are
 visible on the back of the pile fabric. A consequence of this is that a
 pattern design formed in the pile fabric is less clearly visible on the
 back. A pile fabric is because of this considered as a fabric of less high
 quality.
 It is also customary to improve the pile loop fastness of these pile
 fabrics by applying a latex layer on the back. The latex layer does not
 penetrate to the pile loops which have been formed around the second weft
 threads running along the pile side. Because of this a good pile loop
 fastness cannot be achieved for these pile loops.
 The purpose of this invention is to provide such a method according to
 which pile fabrics can be woven without the above described disadvantages.
 This purpose is achieved according to this invention with a method for
 weaving pile fabrics with the characteristics mentioned in the first
 paragraph of this specification, whereby the dead pile warp threads,
 running along the pile side of the second weft threads, are inwoven.
 With a pile fabric woven according to this method the first and the second
 weft threads run along the back of the dead pile warp threads, through
 which these pile warp threads are not pushed through to the back of the
 fabric. The pattern design can because of this be discerned very clearly
 and perfectly on the back of the fabric. Furthermore the pile loops formed
 around the second weft threads now lie almost against the tension warp
 thread, so that a latex layer applied on the back of the pile fabric can
 penetrate much better to these pile loops. The pile loop fastness of these
 pile loops is because of this considerably improved.
 With the method according to this invention third weft threads are
 preferably inwoven in each backing fabric, which run along the pile side
 of the dead pile warp threads. The dead pile warp threads are thus inwoven
 between the second and the third weft threads.
 According to a preferred method according to this invention each third weft
 thread is provided between the tufts of a respective pile loop.
 Furthermore in each backing fabric a pile loop can be formed alternately
 around a first and around a second weft thread.
 The method is preferably so implemented that each backing fabric comprises
 successive groups of weft threads, which comprise a first, a second, and a
 third weft thread.
 If furthermore a respective pile loop is formed around the first and around
 the second weft thread of each group a pile fabric is obtained with a
 maximum pile density.
 Very preferred pile fabrics are obtained if per warp thread system for each
 backing fabric two binding warp threads are provided so that these binding
 warp threads cross each other repeatedly, and so that a group of weft
 threads extends in each opening between two successive crossings of these
 binding warp threads.
 For example successive series of six weft threads can be inserted on a
 weaving machine, whereby each series comprises a first, a second and a
 third weft thread of the top backing fabric, and a first, a second and a
 third weft thread of the bottom backing fabric, and whereby per weft
 insertion cycle in each case one weft thread is inserted.
 The positions of a pile-forming pile warp thread in relation to the
 successive weft threads can with this method in each case be repeated
 after the insertion of a series of six weft threads, therefore after six
 weft insertion cycles. The pile-forming pile warp threads therefore have a
 repeat of 6 weft insertion cycles.
 If the binding warp threads in each backing fabric run alternately above
 and below a group of weft threads, then their positions in relation to the
 successive weft threads are repeated after the insertion of two series of
 weft threads or after 12 weft insertion cycles. The binding warp threads
 therefore have a repeat of 12 weft insertion cycles. The weaving machine
 must in this case be provided with weaving frames with an operating repeat
 of 12 weft insertion cycles.
 This method can be utilized on a weaving machine with one weft insertion
 means, such as e.g. a single rapier weaving machine.
 By so inserting a series of weft threads successively a third weft thread
 is preferably inserted in the top backing fabric, a first weft thread in
 the top backing fabric, a second weft thread in the bottom fabric, a
 second weft thread in the top backing fabric, a first weft thread in the
 bottom backing fabric, and a third weft thread in the bottom backing
 fabric.
 The method according to this invention can however be performed faster and
 therefore more economically if the six weft threads of a series on a
 weaving machine are inserted in the course of less than six successive
 weft insertion cycles. The six weft threads can for example be inserted in
 the course of four successive weft insertion cycles, whereby in the course
 of two of these insertion cycles in each case two weft threads are
 inserted, and in the course of the other two weft insertion cycles in each
 case one weft thread is inserted.
 Weaving according to this weaving method progresses 1.5 times faster than
 weaving according to a method whereby per weft insertion cycle one weft
 thread is inserted. With this method the working pile warp threads have a
 repeat of four weft insertion cycles. The binding warp threads have a
 repeat of eight weft insertion cycles, so that the weaving frames can work
 with an operating repeat of eight weft insertion cycles.
 If this method is to be utilized a weaving machine is necessary with weft
 insertion means which are provided for inserting at least two weft threads
 per weft insertion cycle.
 By so inserting a series of weft threads preferably on the one hand the
 first and the third weft thread of the top backing fabric, and on the
 other hand the first and the third weft thread of the bottom backing
 fabric are inserted together in the course of respective weft insertion
 cycles, while the second weft thread of the bottom backing fabric and the
 second weft thread of the top backing fabric are inserted in the course of
 different weft insertion cycles.
 Preferably two weft threads are then inserted in the course of the first
 and the fourth insertion cycle.
 The method is utilized in a very efficient manner on a weaving machine with
 weft insertion means which are provided for inserting a respective weft
 thread per weft insertion cycle at least at three different levels.
 The first and the third weft thread of the top fabric can then be inserted
 together, respectively at the top and at the middle insertion level, while
 at the bottom insertion level no weft thread is inserted. The second weft
 thread of the bottom backing fabric and the second weft thread of the top
 backing fabric can respectively be inserted at the bottom and the top
 insertion level while at the two other insertion levels no weft thread is
 inserted. The first and the third weft thread of the bottom backing fabric
 can also be inserted together, respectively at the middle and at the
 bottom insertion level, while at the top insertion level no weft thread is
 inserted.
 This method offers the advantage that the dead pile warp threads can always
 be held at the same height between the insertion levels. In the course of
 the successive weft insertion cycles the dead pile warp threads which have
 to be inwoven in the top backing fabric can be held between the top and
 the middle insertion level, while the dead pile warp threads which have to
 be inwoven in the bottom backing fabric can be held between the middle and
 the bottom insertion level.
 The dead pile warp threads are because of this less stressed. The device
 for positioning the pile warp threads in relation to the weft insertion
 levels (e.g. a jacquard machine) will only have to position the
 pile-forming pile warp threads, and will therefore be less stressed and
 consume less energy.
 Preferably during the operation of this weaving machine at least at one
 insertion level no weft thread is inserted by disengaging the weft
 insertion means in question or by preventing this weft insertion means
 from being able to take along a weft thread.
 In the following two possible weaving methods according to this invention
 are described in greater detail. This specification only serves to explain
 further the characteristics of the method and the pile fabrics according
 to the invention, and to specify further properties and distinctive
 features thereof, and cannot therefore be regarded as a restriction on the
 protection claimed for this invention in the claims of this patent
 application.

On a single rapier face-to-face weaving machine weft threads (1-6) are in
 successive sheds brought between the warp threads (7-20) of a series of
 warp thread systems, so that two backing fabrics (21), (22) are woven
 located one above the other, while pile warp threads (13, 14, 20) are
 alternately passed around a weft thread (1), (2) of the top backing fabric
 (21) and around a weft thread (4), (5) of the bottom backing fabric (22),
 so that respective pile loops are formed (see FIG. 1).
 Two tension warp threads (7), (10), four binding warp threads (8), (9),
 (11), (12), and eight pile warp threads (13-20) are provided in each warp
 thread system. During the operation of the weaving machine in the course
 of successive weft insertion cycles in each case one weft thread (1), (2),
 (3), (4), (5), (6) is brought to a fixed insertion level between the warp
 threads (7-20). Each warp thread is in each case brought into the correct
 position (above or below this insertion level) prior to the insertion of a
 weft thread in order to weave the face-to-face pile fabric represented in
 FIG. 1. The positioning of the pile warp threads can for example be
 effected by a jacquard machine.
 Two backing fabrics (21), (22) are woven located one above the other with
 tension warp threads (7), (10) and inwoven dead pile warp threads (13-20)
 . Per warp thread system the warp threads (7-20) are so positioned that in
 each backing fabric (21), (22) one tension warp thread (7), (10) and the
 non-pile-forming parts of four pile warp threads (13-16), (17-20) are
 inwoven, and that in each backing fabric (21), (22) successive groups of
 three weft threads (1-3), (4-6) are inwoven in respective successive
 openings between two binding warp threads (8), (9); (11), (12).
 The three successive weft threads (3, 1, 2) of each group in the top
 backing fabric (21) are moreover respectively inwoven along the pile side
 of the dead pile warp threads (13-16) and the tension warp thread (7),
 along the back of the dead pile warp threads (13-16) and the tension warp
 thread (7), and between the dead pile warp threads (13-16) and the tension
 warp thread (7).
 The three successive weft threads (4, 6, 5) of each group in the bottom
 backing fabric (22) are moreover respectively inwoven along the back of
 the dead pile warp threads (17-20) and the tension warp thread (10), along
 the pile side of the dead pile warp threads (17-20) and the tension warp
 thread (10), and between the dead pile warp threads (17-20) and the
 tension warp thread (10).
 In each warp thread system at least one pile warp thread (13, 14, 20) forms
 pile loops because of the fact that alternately in the top (21) and the
 bottom backing fabric (22) it is passed around a weft thread (1), (2),
 (4), (5). Moreover in each backing fabric around each weft thread (1), (4)
 which is located along the back of the tension warp thread (7), (10) (a
 first weft thread) and around each weft thread (2), (5) which is located
 between the tension warp thread (7), (10) and the dead pile warp threads
 (13-16), (17-20) (a second weft thread) a respective pile loop is formed.
 The successive pile loops are therefore alternately formed around a first
 (1), (4) and around a second (2), (5) weft thread.
 The tufts of the pile loops which are formed around a first weft thread
 (1), (4), are on both sides of a weft thread (3), (6) which runs along the
 pile side of the tension warp thread (7), (10) and the dead pile warp
 threads (13-20) (a third warp thread).
 The weft threads (1-6) inserted one after another can be divided into
 successive series of six successive weft threads, whereby the weft threads
 of each series respectively occupy the same positions in the fabrics. Of
 each series the successively inserted weft threads are so inwoven that in
 the fabrics they respectively become a third weft thread (3) in the top
 backing fabric, a first weft thread (1) in the top backing fabric, a
 second weft thread (5) in the bottom backing fabric, a second weft thread
 (2) in the top backing fabric, a first weft thread (4) in the bottom
 backing fabric, and a third weft thread (6) in the bottom backing fabric.
 With each series of weft threads (1-6) a first (1), (4), a second (2), (5)
 and a third weft thread (3), (6) is therefore inserted both in the top
 (21) and in the bottom backing fabric (22).
 In the figures in each case a warp thread system is represented in which
 several pile warp threads (13, 14, 18, 20) in turn form pile loops.
 The pile-forming pile warp threads (13, 14, 20) are cut through between the
 two backing fabrics (21), (22) so that two separate pile fabrics are
 obtained.
 In these pile fabrics the dead pile warp threads (13-20) are not pushed
 through to the back, so that the pattern design formed by the pile warp
 threads is very perfectly and clearly discernible on the fabric back. The
 pile loop fastness of the pile loops which have been formed around the
 second weft threads (2), (5) can also be considerably improved in
 comparison to the existing pile fabrics of this type, since a latex layer
 (or any other fixing agent) applied to the fabric back can penetrate well
 to these pile loops.
 The method illustrated by FIGS. 2 and 3 differs from the method which has
 been described above with reference to FIG. 1, principally because of the
 fact that now on the one hand the first (1) and the third weft thread (3)
 of the top backing fabric (21), and on the other hand the first (4) and
 the third weft thread (6) of the bottom backing fabric (22) are inserted
 together one above the other in the course of the respective weft
 insertion cycles on a triple rapier face-to-face weaving machine. This
 weaving machine is provided in order in the course of each weft insertion
 cycle to insert a respective weft thread at a top, a middle and a bottom
 insertion level.
 The above mentioned series of six weft threads is according to this method
 therefore inserted in the course of four successive weft insertion cycles.
 Because of this according to this method weaving can be effected 50%
 faster.
 The insertion of a series of weft threads (1-6) occurs as follows:
 in the course of a first weft insertion cycle the first (1) and the third
 weft thread (3) for the top backing fabric (21) are inserted, respectively
 at the top and at the middle insertion level;
 in the course of a second weft insertion cycle the second weft thread (5)
 for the bottom backing fabric (22) is inserted at the bottom insertion
 level;
 in the course of a third weft insertion cycle the second weft thread (25)
 for the top backing fabric (21) is inserted at the top insertion level;
 and
 in the course of a fourth weft insertion cycle the first (4) and the third
 weft thread (6) for the bottom backing fabric (22) are inserted,
 respectively at the middle and at the bottom insertion level.
 In the course of these four weft insertion cycles no weft thread has
 therefore to be inserted first at the bottom insertion level, subsequently
 at the top and the middle insertion level, thereafter at the middle and
 the bottom insertion level, and finally at the top insertion level. In
 order not to insert a weft thread at a specific insertion level the weft
 insertion means operating at that insertion level can be disengaged or it
 can be ensured that the operating weft insertion means does not have a
 weft thread presented to it. For the latter mentioned possibility the term
 weft cancellation is used.
 In FIG. 2 the insertion positions of the non-inserted weft threads are
 indicated. At the insertion positions (23) indicated by a circle no weft
 thread is inserted by disengaging a weft insertion means. At the positions
 (24) which have been indicated by a crossed circle no weft thread is
 inserted through the application of weft cancellation.
 According to this method the dead pile warp threads (13-16) inwoven in the
 top backing fabric can in the course of the successive weft insertion
 cycles be held at the same height, between the top and the middle
 insertion level. The dead pile warp threads (17-20) inwoven in the bottom
 backing fabric can in the course of the successive weft insertion cycles
 be held at the same height, between the middle and the bottom insertion
 level.
 The method illustrated by FIG. 4 is implemented on a single rapier
 face-to-face weaving machine. In successive sheds between warp threads
 (7-15, 17, 18) of a series of warp thread systems weft threads (1-6) are
 inserted, so that two backing fabrics (21), (22) are formed located one
 above the other, while pile warp threads (13, 14, 15, 17, 18) are
 alternately passed around a weft thread (1), (2) of the top backing fabric
 (21) and around a weft thread (4), (5) of the bottom backing fabric (22),
 so that respective pile loops are formed.
 Each warp thread system comprises two tension warp threads (7), (10), four
 binding warp threads (8), (9) (11), (12) and five pile warp threads (13),
 (14), (15), (17), (18). In the course of successive waft insertion cycles
 of the weaving machine in each case one weft thread (1), (2), (3), (4),
 (5), (6) is brought to a fixed insertion level between the warp threads.
 These warp threads are positioned by a jacquard machine in relation to
 this insertion level, in order to weave the face-to-face pile fabric
 represented in FIG. 4.
 Two backing fabrics (21), (22) are woven located one above the other, in
 which successive groups of three weft threads (1-3) (4-6) are inwoven in
 respective successive openings between two binding warp threads (8), (9);
 (11), (12).
 The three successive weft threads (1, 3, 2) of each group in the top
 backing fabric (21) are moreover respectively inwoven along the back of
 the dead pile warp threads (13, 14, 15, 17, 18) and the tension warp
 thread (7), along the pile side of the dead pile warp threads (13, 14, 15,
 17, 18) and the tension warp thread (7) and between the dead pile warp
 threads (13, 14, 15, 17, 18) and the tension warp thread (7).
 The positions of the successive weft threads (5), (4), (6) of each group in
 the bottom fabric (22) are the same as in the top fabric (21).
 The weft threads (1-6) inserted one after another can be divided into
 successive series of six successive weft threads. These successive weft
 threads are in each case so inwoven that they respectively form a
 successive first weft thread (1) in the top backing fabric, a third weft
 thread (3) in the top backing fabric, a second weft thread (5) in the
 bottom backing fabric, a second weft thread (2) in the top backing fabric,
 a first weft thread (4) in the bottom backing fabric, and a third weft
 thread (6) in the bottom backing fabric.
 The weave implemented according to this method differs from the one
 according to FIG. 1 because of the fact that in each group of weft threads
 of the top backing fabric first the first weft thread (1) and thereafter
 the third weft thread (3) is inserted, while this is the other way around
 with the method according to FIG. 1.
 According to this single-bobbin weaving method (FIG. 4) the weft threads
 (1-6) are each separately inserted successively in a single or double
 shed.
 An advantage of this weaving method is that it can be implemented with a
 two-position open-shed jacquard machine. With single-bobbin weaving with a
 double rapier weaving machine lancets can be utilized for better
 controlling the pile height.
 The productivity of this weaving method however leaves something to be
 desired. Three machine revolutions are necessary in order to form two pile
 rows. The repeat of the warp threads of the backing fabric is 12. Such a
 long repeat is difficult to implement with a cam drum.
 The method illustrated by FIGS. 5 and 6 is implemented on a double rapier
 face-to-face weaving machine. Each series of six weft threads (1-6) is
 inserted in the course of four successive weft insertion cycles. In the
 first insertion cycle the first (1) and the third weft thread (3) of the
 top backing fabric (21) are inserted together one above the other. These
 weft threads (1), (3) are inserted in the shed for the top fabric (21),
 but the first weft thread (1) is inserted at the level of the top fabric
 (21) while the third weft thread (3) is inserted at the level of the
 bottom fabric (22).
 The binding warp thread (9) of the top fabric (21) is then in a "bottom"
 position, below the insertion level at the level of the bottom fabric
 (22). This binding warp thread (9) then pulls the third weft thread (3)
 toward the top backing fabric (21), as appears from FIG. 6.
 In the second insertion cycle the second weft thread (5) is inserted in the
 bottom backing fabric (22). In the third insertion cycle following
 thereafter the second weft thread (2) is inserted in the top backing
 fabric (21).
 In the fourth insertion cycle the first (4) and the third weft thread (6)
 of the bottom backing fabric are inserted together one above the other.
 These weft threads (4), (6) are inserted in the shed for the bottom fabric
 (22), but the first weft thread (4) is inserted at the level of the bottom
 fabric (22), while the third weft thread (6) is inserted at the level of
 the top fabric (21). The binding warp thread (11) of the bottom fabric
 (22) is then in a "top" position above the top insertion level, and pulls
 the third weft thread (6) toward the bottom backing fabric (22), as
 appears from FIG. 6.
 The advantage of this weaving method is that it can be implemented with a
 double rapier weaving machine, provided with a normal three-position
 jacquard machine. The repeat of the backing weave is 8, which can be well
 implemented with a cam drum.
 This weaving method however has the disadvantage that the sheds for the
 binding warp threads have to be cyclically very large. This is not ideal
 for a good pile formation and more specifically for obtaining a uniform
 pile height. With this method the use of lancets is not possible, since
 weft threads have to be able to move from the level of the top fabric to
 the level of the bottom fabric, and vice versa. The use of lancets is also
 not possible with the above described triple rapier weaving method (FIGS.
 2 and 3).