Method for weaving a false bouclé fabric

Abstract: Method for weaving fabrics with a rib structure, in particular false bouclé fabrics, whereby on a weaving machine in successive weft insertion cycles in each case a top (1), (2), (3) and a bottom weft thread (4), (5), (6) are inserted between binding warp threads (9-12) and pattern warp threads (13-16) of a series of warp thread systems so that a fabric is woven in which top (1-3) and bottom weft threads (4-6) are inwoven by a respective set of binding warp threads (9, 10), (11, 12), whereby two backing fabrics are woven, and in which respective pattern warp threads (13), (14); (15), (16) are interlaced in a respective backing fabric and are rib-formingly passed round over a top (2), (3) or bottom weft thread (5), (6) running between the backing fabrics which is not inwoven by binding warp threads (9-12), so that two fabrics (17), (18) with a rib structure are woven one above the other. This method makes it possible to weave fabrics with a rib structure on a double rapier weaving machine with a considerably higher productivity than in the past.

Description: This invention relates to a method for manufacturing fabrics with a rib structure, whereby on a weaving machine in successive weft insertion cycles in each case a top and a bottom weft thread are inserted between warp threads of a series of warp thread systems so that, a fabric is woven in which warp threads are alternately interlaced in the fabric and are rib-formingly passed round over a weft thread. This invention also relates to a fabric with rib structure manufactured according to this method. A fabric with a rib structure which approximates the appearance of a loop pile fabric or bouclé fabric, is called a false bouclé fabric. DE-A- 4 312 235 relates to a method and an apparatus for simultaneously weaving two pile loop weaves ("Schlingenpolgewebe"). A pile loop weave is a weave in which the pile warp threads are alternately tied in a backing fabric, and forming loops which extend outside that backing fabric. In order to form loops, the pile warp threads must be passed over an element which is positioned at a distance from the backing fabric. This distance determines the length of the loops. In the method according to DE-A-4 312 235, auxiliary weft threads ("Hilfsschüsse 16, 26") are kept at a distance from the backing fabrics by the "Polplatinen 3" (see fig. 1), which extend in the warp direction in between the two backing fabrics. The auxiliary weft threads function as an element (at a distance from the backing fabric) over which the pile warp threads can be passed in order to form loops. Once the loops are formed, these auxiliary weft threads ("Hilfsschüsse 16, 26") are not necessary anymore, and they can be removed. The auxiliary weft threads are thus not an essential component of the loops. These auxiliary weft threads also are not lying on the surface of the backing fabric, but are kept at a adistance from the backing fabrics. The appearance of the loops also is not determined by the auxiliary weft threads. The loop appearance (the length of the loops) is determined by the distance between the auxiliary weft threads and the backing fabric. Said distance is determined by the height and the position of the "Polplatinen 3" (see fig. 1 of DE-A-4 312 235). In this method, the use of the "Polplatinen 3" in order to keep the auxiliary weft threads at a distance from the backing fabrics is essential. This invention relates in particular to a method for weaving a false bouclé fabric, and a false bouclé fabric that has been woven according to this weaving method. According to a known weaving method for manufacturing a false bouclé fabric, which has the above mentioned characteristics, tension warp threads are inwoven stretched in the fabric and in each weft insertion cycle on the weaving machine two weft threads are simultaneously inserted one above the other. In successive insertion cycles the two weft threads are in relation to the tension warp threads alternately inserted along the top of the fabric and along the back of the fabric. Two pattern warp threads with a different colour are provided in order to be able to make a design or a pattern visible with the two colours along the top of the fabric. A first pattern warp thread is alternately brought above the two weft threads along the top of the fabric and interlaced between the two weft threads along the back of the fabric, in order to implement a rib structure on the top of the fabric and to form the design or the pattern. A second pattern warp thread is alternately interlaced between the two weft threads along the top of the fabric and brought under the two weft threads along the back of the fabric. The colour of the second pattern warp thread is then visible on the back of the fabric. The second pattern warp thread forms a rib structure on the back of the fabric. With these fabrics the weft threads are inwoven by the pattern warp threads. With each insertion cycle a rib line is produced (alternately along the top and along the back of the fabric). On the back of the fabric a type of negative (with swapped colours) is obtained of the two-coloured design which is visible on the top of the fabric. Manufacturing fabrics with a rib structure on a weaving machine can be effected according to this known method but with an average productivity. The purpose of this invention is to provide a method for weaving a fabric with a rib structure, which can be utilised on a weaving machine which is provided for inserting two weft threads per weft insertion cycle, and with which a considerably higher productivity can be achieved than with the known method. This objective is achieved according to this invention with a method having the characteristics mentioned in the first paragraph of this specification, by providing binding warp threads and pattern warp threads in each warp thread system, so that top and bottom weft threads are inwoven by a respective set of binding warp threads whereby two backing fabrics are woven, and so that respective pattern warp threads are alternately interlaced in a respective backing fabric and are rib-formingly passed round over a top or bottom weft thread running between the backing fabrics which is not inwoven by binding warp threads, so that two fabrics with a rib structure are woven one above the other. According to the method according to this invention on a weaving machine two fabrics can be woven simultaneously. The application of this method instead of the known method therefore doubles the productivity. This method can be utilised on a weaving machine which is provided for inserting two weft threads per weft insertion cycle, such as for example a double rapier weaving machine. According to a greatly preferred method according to this invention the weft threads are inserted in successive series of three weft insertion cycles, whereby of the weft threads inserted in each series in each case two top weft threads are inwoven in the top backing fabric and two bottom weft threads are inwoven in the bottom backing fabric, while round the two other weft threads a respective rib is formed by a pattern warp thread interlaced in the top backing fabric and by a pattern warp thread interlaced in the bottom backing fabric. This method can be so utilised that the pattern warp threads interlaced in the top backing fabric are rib-formingly passed round over a bottom weft thread while the pattern warp threads interlaced in the bottom backing fabric are rib-formingly passed round over a top weft thread. With a fabric manufactured according to this method the ribs are formed above two weft threads running one above the other. In such a fabric the rib height is rather great, through which a very clear rib structure is obtained. The rib-forming pattern warp threads must with this method be capable in each weft insertion cycle of being brought "above" and "below" the two insertion levels of the weaving machine. In order to inweave non-rib-forming (parts of) pattern warp threads in a backing fabric these pattern warp threads must furthermore also be capable of being brought into a position "between" the insertion levels. The utilisation of this method therefore requires a three-position open-shed jacquard machine. This method is for example so utilised that the pattern warp thread interlaced in the top backing fabric forms a rib round the bottom weft thread which is inserted during the second weft insertion cycle of each series and the pattern warp thread interlaced in the bottom backing fabric forms a rib round the top weft thread which is inserted during the third weft insertion cycle of each series. In order to remedy the disadvantage that the above described method requires a three-position open-shed jacquard machine, the method according to this invention is so implemented that the pattern warp threads interlaced in the top backing fabric are rib-formingly passed round over a top weft thread, while the pattern warp threads interlaced in the bottom backing fabric are rib-formingly passed round over a bottom weft thread. On the one hand both the formation of ribs with the pattern warp threads interlaced in the top backing fabric and the inweaving of non-rib-forming (dead) pattern warp threads in the top backing fabric can be performed with the positions "above" and "between" the insertion levels. On the other hand both the formation of ribs with the pattern warp threads interlaced in the bottom backing fabric and the inweaving of non-rib-forming (dead) pattern warp threads in the bottom backing fabric can be performed with the positions "between" and "below" the insertion levels. This method can therefore be implemented utilising a two-position open-shed jacquard machine. The jacquard machine must furthermore only perform half the total lifting. According to this method the weft threads are, as mentioned above, preferably inserted in successive series of three weft insertion cycles, so that the pattern warp thread interlaced in the top backing fabric forms a rib round the top weft thread which is inserted during the third weft insertion cycle of each series, and so that the pattern warp thread interlaced in the bottom backing fabric forms a rib round the bottom weft thread which is inserted during the third weft insertion cycle of each series. With the method according to this invention the height of the ribs in the fabric can be increased by taking thicker threads for the weft threads which support ribs than for the other weft threads. Because of this the loop effect of the rib structure is increased and a good approximation to the appearance of a loop pile fabric or a bouclé fabric is obtained. The non-rib-forming pattern warp threads or parts of pattern warp threads (called the dead pattern warp threads in that which follows) are preferably inwoven in a backing fabric. According to this method, per warp thread system, a respective tension warp thread is preferably also inwoven in each backing fabric. The inwoven dead pattern warp threads and the tension warp threads moreover extend together in the backing fabrics. This invention will now be further explained in the following specification of a number of methods for manufacturing false bouclé fabrics according to this invention. These methods are only described by way of example and no part of the following specification may therefore be considered as restrictive to the protection claimed by this patent application. In this specification reference is made to figures 1, 2 and 3 attached hereto and provided with reference numbers, which represent schematic cross-sections according to the direction of the warp threads of false bouclé fabrics, respectively manufactured according to a first, a second and a third variant method according to this invention. According to a first variant method according to this invention (see figure 1) on a double rapier weaving machine a number of warp thread systems are provided which respectively comprise two tension warp threads (7), (8), four binding warp threads (9), (10), (11), (12), and four pattern warp threads (13), (14), (15) (16). During successive weft insertion cycles in each case a top weft thread (1), (2), (3) and a bottom weft thread (4), (5), (6) are simultaneously inserted between the warp threads (7-16). The various warp threads (7-16) are brought into the correct position in relation to the two insertion levels prior to each weft insertion in order to obtain the path schematically represented in figure 1 of the warp threads (7-16) in relation to weft threads (1-3), (4-6), whereby two fabrics with a rib structure are woven one above the other. Moreover two backing fabrics are formed, whereby each backing fabric in each warp thread system comprises two binding warp threads (9), (10); (11), (12) which cross each other repeatedly and enclose two weft threads (1), (2); (4), (6) in each opening formed between two crossings, and comprise a tension warp thread (7), (8) which extends between the two weft threads which are in the respective openings between binding warp threads. Each fabric (17), (18) also comprises two pattern warp threads (13), (14); (15) (16) in each warp thread system which alternately form ribs, because of the fact that they are alternately interlaced in the fabric by a weft thread (1), (4) and are rib-formingly passed round over a thicker weft thread (5), (3) which extends between the two backing fabrics. The positions of the various warp threads (7-16) in relation to the weft threads (1-6) are in each case repeated after a series of three successive weft insertion cycles. The top weft thread (1) and the bottom weft thread (4) which are inserted during the first weft insertion cycle of a number of successive series of three insertion cycles, are respectively inwoven in the top and the bottom backing fabric. The top (2) and the bottom weft thread (5) which are inserted during the second weft insertion cycle of the successive series, are respectively inwoven in the top backing fabric and provided between the two backing fabrics. During this second weft insertion cycle no weft thread is inwoven in the bottom backing fabric. The top and the bottom weft thread (6) which are inserted during the third weft insertion cycle of the successive series, are respectively provided between the two backing fabrics and inwoven in the bottom backing fabric. During this third weft insertion cycle no weft thread is inwoven in the top backing fabric. A pattern warp thread (13), (14) is alternately interlaced in the top backing fabric by a weft thread (1) and rib-formingly passed round over the weft thread (5) which during the second weft insertion cycle is provided between the two backing fabrics. Another pattern warp thread (15), (16) is alternately interlaced in the bottom backing fabric by a weft thread (4) and rib-formingly passed round over the weft thread (3) which during the third weft insertion cycle is provided between the two backing fabrics. The non-rib-forming parts of the pattern warp threads (13-16) are inwoven in the backing fabric married to the tension warp threads (7), (8). According to a second variant method according to this invention (see fig. 2) the pattern warp threads (13-16) are positioned by means of a two-position open-shed jacquard machine. This method also differs further from the first variant method because of the fact that the two weft threads which are provided for supporting the ribs between the backing fabrics are now respectively the top (3) and the bottom weft thread (6) which is inserted during every third weft insertion cycle of the successive series. These weft threads (3), (6) are one above the other so that the rib-forming pattern warp threads (13), (15) run between the two weft threads (3), (6). Of the weft threads (1), (2); (4), (5) which are inserted during the first and the second weft insertion cycle the respective top weft threads (1), (2) are inwoven in the top backing fabric and the respective bottom weft threads (4), (5) inwoven in the bottom backing fabric. A third variant method (see figure 3) differs from the second, only because of the fact that the weft threads (2), (3) which support the ribs are now inserted during the second weft insertion cycle. This invention makes it possible, when weaving fabrics with a rib structure on a weaving machine which can only insert two weft threads per weft insertion cycle, to increase productivity to a great degree.

Claims: Method for weaving fabrics with a rib structure, whereby on a weaving machine in successive weft insertion cycles in each case a top (1), (2), (3) and a bottom weft thread (4), (5), (6) are inserted between warp threads (7-16) of a series of warp thread systems so that a fabric is woven in which warp threads (13-16) are alternately interlaced in the fabric and are rib-formingly passed round over a weft thread (2), (3), (5), (6), characterised in that binding warp threads (9-12) and pattern warp threads (13-16) are provided in each warp thread system so that top (1-3) and bottom weft threads (4-6) are inwoven by a respective set of binding warp threads (9, 10), (11, 12) whereby two backing fabrics are woven, and so that respective pattern warp threads (13), (14); (15), (16) are alternately interlaced in a respective backing fabric and are rib-formingly passed round over a top (2), (3) or bottom weft thread (5), (6) running between the backing fabrics which is not inwoven by binding warp threads (9-12), so that two fabrics (17), (18) with a rib structure are woven one above the other. Method for weaving a fabric with a rib structure according to claim 1 characterised in that the weft threads are inserted in successive series of three weft insertion cycles, whereby of the weft threads inserted in each series in each case two top weft threads (1), (2) are inwoven in the top backing fabric and two bottom weft threads (4), (6); (4), (5) are inwoven in the bottom backing fabric, while round the two other weft threads (5), (3); (3), (6) a respective rib is formed by a pattern warp thread (13), (14) interlaced in the top backing fabric and by a pattern warp thread (15), (16) interlaced in the bottom backing fabric. Method for weaving fabrics with a rib structure, according to claim 1 or 2 characterised in that the pattern warp threads (13), (14) interlaced in the top backing fabric are rib-formingly passed round over a bottom weft thread (5), while the pattern warp threads (15), (16) interlaced in the bottom backing fabric are rib-formingly passed round over a top weft thread (3). Method for weaving a fabric with a rib structure according to claims 2 and 3 characterised in that the pattern warp thread (13), (14) interlaced in the top backing fabric forms a rib round the bottom weft thread (5) which is inserted during the second weft insertion cycle of each series and the pattern warp thread (15), (16) interlaced in the bottom backing fabric forms a rib round the top weft thread (3) which is inserted during the third weft insertion cycle of each series. Method for weaving fabrics with a rib structure, according to claim 1 characterised in that the pattern warp threads (13), (14) interlaced in the top backing fabric are rib-formingly passed round over a top weft thread (2), (3), while the pattern warp threads (15), (16) interlaced in the bottom backing fabric are rib-formingly passed round over a bottom weft thread (5), (6). Method for weaving a fabric with a rib structure according to claims 2 and 5 characterised in that the pattern warp thread (13), (14) interlaced in the top backing fabric forms a rib round the top weft thread (3) which is inserted during the third weft insertion cycle of each series and that the pattern warp thread (15), (16) interlaced in the bottom backing fabric forms a rib round the bottom weft thread (6) which is inserted during the third weft insertion cycle of each series. Method for weaving a fabric with a rib structure according to any of the preceding claims characterised in that the weft threads (3), (5); (3), (6); (2), (5) which are provided for supporting the ribs are thicker than the other weft threads. Method for weaving a fabric with a rib structure according to any of the preceding claims characterised in that a non-rib-forming part of a pattern warp thread (13-16) is inwoven in a backing fabric. Method for weaving a fabric with a rib structure according to any of the preceding claims characterised in that , per warp thread system, a respective tension warp thread (7), (8) is inwoven in each backing fabric.

Inventors: DEBAES JOHNNY, DEBAES, JOHNNY
Applicants: WIELE MICHEL VAN DE NV, N.V. MICHEL VAN DE WIELE
Application year: 1999
Main classification: D03D27
IPC codes: D03D27