FABRIC TAPE

Abstract

A forming fabric tape for a machine for producing or processing a fiber material web, the forming fabric tape including an upper fabric layer including upper longitudinal threads and upper transversal threads woven into the upper longitudinal threads; and a lower fabric layer including lower longitudinal threads and lower transversal threads woven into the lower longitudinal threads, wherein the upper fabric layer and the lower fabric layer are arranged on top of one another so that the upper fabric layer is oriented towards the fiber material web and the lower fabric layer is oriented away from the fiber material web, wherein the upper longitudinal threads are offset from each other unevenly, wherein the upper longitudinal threads are arranged so that average distances of the upper longitudinal threads have the following sequence which is repeated continuously in the transversal direction of the fabric tape: large distance, large distance, small distance.

Claims

1. A forming fabric tape for a machine for producing or processing a fiber material web, the forming fabric tape comprising: an upper fabric layer including upper longitudinal threads and upper transversal threads woven into the upper longitudinal threads; and a lower fabric layer including lower longitudinal threads and lower transversal threads woven into the lower longitudinal threads, wherein the upper fabric layer and the lower fabric layer are arranged on top of one another so that the upper fabric layer is oriented towards the fiber material web and the lower fabric layer is oriented away from the fiber material web, wherein the upper longitudinal threads are offset from each other unevenly, wherein the upper longitudinal threads are arranged so that average distances of the upper longitudinal threads have the following sequence which is repeated continuously in the transversal direction of the fabric tape: large distance, large distance, and small distance, and wherein a difference between an average large distance and an average small distance is at least 50% of a diameter of an upper longitudinal thread.

2. The forming fabric tape according to claim 1, wherein the large distance is between 100% and 300% of the diameter of the upper longitudinal thread or the small distance is between 30% and 125% of the diameter of the upper longitudinal thread.

3. The forming fabric tape according to claim 1, wherein a ratio of upper warp threads to lower warp threads in the fabric tape is 1:1, and wherein the lower warp threads are spaced identically from each other.

4. The forming fabric tape according to claim 1, wherein a weave pattern of the forming fabric tape is repeated in pattern repeats, wherein the upper longitudinal threads and the lower longitudinal threads are arranged in each pattern repeat in plural groups including a first group and a second group and at least one additional first group or second group, and wherein each first group is formed respectively from an upper longitudinal thread and a lower longitudinal thread arranged below the upper longitudinal thread and each second group is formed respectively from an upper longitudinal thread and two lower longitudinal threads arranged below the upper longitudinal thread.

5. The forming fabric tape according to claim 4, wherein the two lower longitudinal threads of a second group have the second distance from each other while the two lower longitudinal threads of a first group and a second group directly adjacent to the first group or the two lower longitudinal threads of two directly adjacent first groups have the first distance from each other.

6. The forming fabric tape according to claim 1, wherein a weaving pattern of the fabric tape is repeated in repeat units, wherein the upper longitudinal threads and the lower longitudinal threads in each repeat unit are arranged in plural groups including a first group and a second group, and wherein the first group is formed from an upper longitudinal thread and a lower longitudinal thread arranged below the upper longitudinal thread and the second group is formed from two upper longitudinal threads and one lower longitudinal thread arranged below the upper longitudinal threads.

7. The forming fabric tape according to claim 4, wherein a first distance between two directly adjacent lower longitudinal threads is greater than a second distance between two directly adjacent lower longitudinal threads, and wherein the difference between the first distance and the second distance is between 25% and 200% of the diameter of the upper longitudinal thread.

8. The forming fabric tape according to claim 1, wherein the difference between the average large distance of two directly adjacent upper longitudinal threads and the average small distance between two directly adjacent longitudinal threads is 200% at the most or 150% at the most of the diameter of the upper longitudinal thread.

9. The forming fabric tape according to claim 1, wherein the first and the second fabric layer are connected with each other through binding threads arranged in pairs.

10. The forming fabric tape according to claim 9, wherein the binding threads extend in a direction of the transversal threads.

11. The forming fabric tape according to claim 9, wherein the two binding threads of a respective binding thread pair are woven in an alternating pattern with upper and lower longitudinal threads and cross over in cross over points when alternating between being woven with the upper longitudinal threads and the lower longitudinal threads and vice versa.

12. The forming fabric tape according to claim 11, wherein each binding thread pair provides at least two intersection points per pattern repeat.

13. The forming fabric tape according to claim 9, wherein the upper fabric layer is formed by weaving the upper longitudinal threads with the upper transversal threads and the binding threads and the lower fabric layer is formed by weaving the lower longitudinal threads with the lower transversal threads.

14. The forming fabric tape according to claim 1, wherein the upper fabric layer forms a plain weave.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The invention is subsequently described based on advantageous embodiments with reference to drawing figures, wherein:

[0029] FIG. 1 illustrates a schematic view of a first embodiment of a fabric tape according to the invention;

[0030] FIG. 2 illustrates a schematic view of a second embodiment of a fabric tape according to the invention; and

[0031] FIG. 3 illustrates a schematic view of a third embodiment of a fabric tape according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0032] FIG. 1 schematically illustrates a first embodiment of a fabric tape according to the invention showing only the upper longitudinal threads O1-O3 and the lower longitudinal threads U1-U3 forming a repeat unit WE in combination but not showing upper transversal threads which are woven with the upper longitudinal threads O1-O3 to form an upper fabric layer, lower transversal threads which are woven with the lower longitudinal threads U1-U3 to form a lower fabric layer and binding threads which connect the upper fabric layer with the lower fabric layer. Thus, the binding threads advantageously are an integral component of the weave, in particular of a linen weave of the upper fabric layer, whereas the binding threads do not contribute to the weave of the lower fabric layer.

[0033] The fabric tape is composed of recurring pattern repeats. With respect to the upper longitudinal threads O1-O3 and the lower longitudinal threads U1-U3 a pattern repeat can include exactly one repeat unit WE. Quite frequently, however, a pattern repeat includes plural repeat units WE. It is appreciated that a pattern repeat is not only defined by the longitudinal threads, but also by the transversal threads and the binding threads. When the outer fabric layer is advantageously configured in plain weave, the pattern repeat has to include an even number of upper longitudinal threads. Since the repeat unit WE in the first embodiment according to FIG. 1 includes three upper longitudinal threads O1-O3, the pattern repeat has to include an integer multiple of the repeat units WE, thus at least two repeat units WE.

[0034] In the instant first embodiment a repeat unit WE is formed from three groups of longitudinal threads, namely three first groups I respectively including only an upper longitudinal thread O1-O3 and a lower longitudinal thread U1-U3. A first relatively large distance a1 is provided between the first upper longitudinal thread O1 and the second upper longitudinal thread O2. The same relatively large distance a1 is also provided between the second upper longitudinal thread O2 the adjacent third upper longitudinal thread O3. Accordingly, the distance a2 between the third upper longitudinal thread O3 and the adjacent upper longitudinal thread O1 of a next repeat unit is significantly smaller. This yields a sequence of the distances of the upper longitudinal threads O1-O3 in the transversal direction of the fabric tape of large distance a1, large distance a1, small distance a2 and this sequence is continuously repeated in the transversal direction. According to the invention the difference between the average large distance a1 and the average small distance a2 is at least 50% of the diameter of the upper longitudinal threads O1-O3. In the illustrated embodiment all upper longitudinal threads have the same circular cross section, whereas all lower longitudinal threads have the same circular second cross section. Furthermore, the two large distances a1 have the same average value in the instant embodiment. This, however, is not mandatory.

[0035] In this first embodiment, the lower longitudinal threads U1-U3 essentially all have the same distance A1 from each other.

[0036] FIG. 2 schematically illustrates a second embodiment of a fabric tape according to the invention showing only the upper longitudinal threads O1-O3 and the lower longitudinal threads U1-U4, forming a repeat unit WE in combination, but not showing the upper transversal threads which are woven with the upper longitudinal threads O1-O3 to form an upper fabric layer, lower transversal threads woven with the upper longitudinal threads U1-U4 to form a lower fabric layer and binding threads which connect the upper fabric layer with the lower fabric layer. Thus, the binding threads are advantageously configured as an integral component of the weave, in particular of a plain weave of the upper fabric layer, whereas they do not contribute to the weave of the lower fabric layer.

[0037] Also this fabric tape is assembled from recurring pattern repeats. With respect to the upper longitudinal threads O1-O3 and the lower longitudinal threads U1-U4 a pattern repeat can be made in principle from exactly one repeat unit WE. Frequently, however, a pattern repeat includes plural repeat units WE. It is appreciated that a pattern repeat is not only defined by the longitudinal threads but also by the transversal threads or binding threads. When the upper fabric layer is advantageously provided as plain weave, a pattern repeat has to include an integer number of upper longitudinal threads. Since the repeat unit WE includes three upper longitudinal threads O1-O3 also in the second embodiment according to FIG. 2, the pattern repeat has to include an integer multiple of the repeat units WE, thus at least 2 repeat units WE.

[0038] In the instant second embodiment, a repeat unit WE is formed from three groups of longitudinal threads, namely a first group I including only an upper longitudinal thread O1 and a lower longitudinal thread U1, a second group including an upper longitudinal thread O2 and two lower longitudinal threads U2 and U3, and an additional first group I including only an upper longitudinal threads O3 and a lower longitudinal thread U4. A first relatively large distance a1 is provided between the first upper longitudinal thread O1 and the second upper longitudinal thread O2. The same relatively large distance a1 is also provided between the second upper longitudinal thread O2 and the adjacent third upper longitudinal thread O3. By comparison the distance a2 between the third upper longitudinal thread O3 and the adjacent upper longitudinal thread O1 of a next repeat unit is significantly narrower. This yields a sequence of the distances of the longitudinal threads O1-O3 in the transversal direction of the fabric tape: large distance a1, large distance a1, small distance a2 and this sequence is continuously repeated in the transversal direction. According to the invention the difference between the average large distance a1 and the average small distance a2 is at least 50% of the diameter of the upper longitudinal thread O1-O3.

[0039] In this second embodiment the lower longitudinal threads U1-U4 have different distances from each other. A first relatively large distance A1 is provided between the first lower longitudinal thread U1 and the second lower longitudinal thread U2, as well as between the third lower longitudinal thread U3 and the fourth lower longitudinal thread U4, whereas a second relatively small distance A2 is provided between the second lower longitudinal thread U2 and the third lower longitudinal thread U3. The first relatively large distance A1 is also arranged between the fourth lower longitudinal thread U4 and a first lower longitudinal thread U1 of a directly adjacent repeat unit. Thus, a continuously repeating sequence of first distance, second distance, first distance, first distance is provided in this embodiment with respect to spacing of the lower longitudinal threads.

[0040] In this embodiment all upper longitudinal threads O1-O3 have identical circular cross sections and all lower longitudinal threads U1-U4 have identical circular cross sections which, however, are greater than the cross sections of the upper longitudinal threads. Furthermore, the two large distances a1, have the same average value in this embodiment for the case of simplicity which, however, is not mandatory. The dimensions in this embodiment can be selected, for example, as follows: [0041] Diameter of upper longitudinal threads O1-O4: 0.14 mm [0042] Diameter of the lower longitudinal threads U1-U3: 0.19 mm [0043] First distance A1: 0.095 mm [0044] First distance A2: 0.049 mm [0045] Distance a1: 0.2645 mm [0046] Distance a2: 0.145 mm

[0047] This yields a total extension of a repeat unit WE of 1.094 mm. The difference between the first distance A1 and the second distance A2 is 0.046 mm which corresponds to 33% of the diameter of the upper longitudinal threads.

[0048] It is appreciated that the distances, in particular the distances a1 and a2 between the upper longitudinal threads O1-O3 do not have to be constant over an entire longitudinal extension of the fabric tape. These distances can also become smaller and larger again. Therefore, the respective average distance is relevant.

[0049] FIG. 3 schematically illustrates a third embodiment of a fabric tape according to the invention showing only the upper longitudinal threads O1-O3 and the lower longitudinal threads U1-U2, which form a repeat unit WE in combination, but not the upper transversal threads which are woven with the upper longitudinal threads O1-O3 to form an upper fabric layer, lower transversal threads which are woven with the lower longitudinal threads U1-U2 to form a lower fabric layer and binding threads which connect the upper fabric layer with the lower fabric layer. Thus, the binding threads advantageously are an integral component of the weaving pattern, in particular of a plain weave of the upper fabric layer, whereas they do not contribute to the weaving pattern of the lower fabric layer.

[0050] Also, this fabric tape, is assembled from recurring pattern repeats. With respect to the upper longitudinal threads O1-O3 and the lower longitudinal threads U1-U2 a pattern repeat can be made from exactly one repeat unit WE. Frequently, however, a pattern repeat includes plural repeat units WE. Thus, it is appreciated that a pattern repeat is not only defined by the longitudinal threads, but also by the transversal threads and binding threads. When the upper fabric layer is advantageously provided in plain weave, a pattern repeat has to include an even number of upper longitudinal threads. Since the repeat unit WE also includes three upper longitudinal threads O1-O3 in the third embodiment according to FIG. 3 the pattern repeat has to include an integer multiple of the repeat units WE, thus at least two repeat units WE.

[0051] In the instant third embodiment a repeat unit WE is formed from two groups of longitudinal threads, namely a first group I including only one upper longitudinal thread O1 and a lower longitudinal thread U1 and a second group including two upper longitudinal threads O1 and O3 and a lower longitudinal thread U2. A first relatively large distance a1 is provided between the upper longitudinal thread O1 and the second upper longitudinal thread O2. The same relatively large distance a1 is also provided between the third upper longitudinal thread O3 and an adjacent first upper longitudinal thread O1 of an adjacent repeat unit WE. By comparison, the distance a2 between the second upper longitudinal thread O2 and the adjacent upper longitudinal thread O3 is significantly smaller. This yields a sequence of the distances of the upper longitudinal threads O1-O3 in the transversal direction of the fabric tape: large distance a1, large distance a1, small distance a2, wherein this sequence is continuously repeated in the transversal direction. According to the invention, the difference between the average large distance a1 and the average small distance a2 is at least 50% of the diameter of the upper longitudinal threads O1-O3.

[0052] In this third embodiment, the lower longitudinal threads U1 and U2 have different distances from each other. A first relatively large distance A1 is arranged between the second lower longitudinal thread U2 and the first lower longitudinal thread U1 of an adjacent repeat unit WE, whereas a second relatively small distance a1 is arranged between the first lower longitudinal thread U1 and the second lower longitudinal thread U2 within the repeat unit WE.

[0053] In this embodiment all upper longitudinal threads O1-O3 have identical circular cross sections and all lower longitudinal threads U1 and U2 have the same circular cross section, which however is greater. Furthermore, the two large distances a1 have the same average value in the instant embodiment for the sake of simplicity which, however, is not mandatory.