1. Field of the Invention
The current invention relates to a woven fabric belt for a machine for the production of web material, especially paper or cardboard, including a web side first woven fabric layer and a machine side second woven fabric layer, in each instance with threads extending in longitudinal direction of the belt and threads extending in cross direction of the belt, whereby the first woven fabric layer and the second woven fabric layer are connected with each other by paired binder threads.
2. Description of the Related Art
A woven fabric belt of this type which can, for example, be utilized as a forming fabric in a machine for the production of paper or cardboard is known from DE 10 2006 008 812 A1. Due to the structure of the fabric belt comprising two fabric layers the possibility is created to provide a very finely structured woven structure at a web contact surface—for example in the form of linen weave—consisting of the threads which extend in machine direction and cross machine direction of this fabric layer and which has only a low tendency of marking. Due to the uneven satin weave at the machine side on the other hand and at the same time because of an uneven distribution of the binding locations of the paired binder threads which provide the connection between the two woven fabric layers a high load capacity, especially in regard to contact with various idler rollers and drive rollers, is provided on the machine side.
What is needed in the art is a fabric belt for a machine for the production of web material whereby an increased stability can be achieved through the utilization of thicker threads in the composition of a machine contact surface, without increasing the thickness of the entire structure.
The present invention provides a fabric belt for a machine for the production of web material, especially paper or cardboard, including a web material side first fabric layer and a machine side second fabric layer, each with threads extending in machine direction and respectively threads extending in cross machine direction, whereby the first fabric layer and the second fabric layer are connected with each other by paired binder threads,
In the inventive fabric belt therefore, groups of threads extending in one direction are generated, whereby in these groups due to gathering of the threads or the compression of the threads against each other the distance between the threads is smaller than the distance between the individual groups. Consequently, comparatively thin threads can be used for the threads of the second fabric layer which extend in the one direction and which, due to gathering into groups, appear to be “thicker threads” and which then produce a very stable machine contact surface together with the threads of the second fabric layer extending in the other direction which can indeed have a larger cross sectional dimension, without the disadvantages that are normally associated with the utilization of very rough fabric structures with thicker threads.
In order to be able to produce an even structure in the other direction it is suggested that groups of threads of the second fabric layer extending in the one direction which are arranged adjacent to each other in the other direction include the same number of threads.
The inventive aspect of gathering individual threads of the second fabric layer extending in the one direction into groups which are then interwoven with threads of the second fabric layer which extend transversely or in other words in the other direction can be utilized especially advantageously if each group of threads of the second fabric layer extending in the one direction includes two threads.
For example, the interaction of the binder thread pairs with the threads of the second fabric layer which extend in the one direction can be such that in a binder thread pair one binder thread progresses alternately on the machine contact side of one group of threads extending in the one direction, and the other binder thread progresses on the machine contact side of the group of threads of the second fabric layer following the one after the next one extending in the one direction.
In addition it is possible that with binder threads which are located immediately after each other in one direction one thread of one pair of threads progresses on the machine contact side of a group of threads of the second fabric layer which extend in the one direction and alternatively one thread of a following pair progresses on the machine contact side of a group of threads of the second fabric layer immediately following in the other direction and extending in the one direction. In this way it can be avoided that—with the same pair of binder threads—in the transition from the first to the second fabric layer and vice versa crossover points are created between two immediately adjacent groups of threads of the second fabric layer which extend in the one direction. On the contrary, such a crossover point can be located on a web side of an additional group of threads of the second fabric layer.
In addition, in order to produce a very finely structured web side contact surface two threads of the first fabric layer which extend in the other direction and two threads of the second fabric layer which extend in the other direction may be provided between two binder thread pairs which are located following each other in the one direction. It should be pointed out here that obviously the number of the specifically available threads in the one direction of the first fabric layer, or the second fabric layer respectively can be selected to be different. This will depend upon how strong the mutual binding together of the two fabric layers needs to be.
For gathering of individual threads into a respective group through the provision of defined tie-off points it is suggested that in each group of tie-off points a first tie-off point and a second tie-off point are formed in the other direction on both sides of the threads of one group of threads of the second fabric layer which extend in the one direction and which are pressed against each other by this group of tie-off points. Here it can be provided that the first tie-off point and the second tie-off point are formed by immediately adjacent threads in the second fabric layer which extend in the other direction.
Moreover, such a group of tie-off points may include a third tie-off point and a fourth tie-off point which are formed in the one direction on both sides of the first tie-off point and the second tie-off point and in the other direction between the first tie-off point and the second tie-off point. Here, it may be provided that the third tie-off point and the fourth tie-off point are formed at immediately adjacent threads extending in one direction of a group of threads of the second fabric layer which extend in the one direction.
The groups of tie-off points provided according to one inventive aspect may, in addition to the previously discussed aspect of formation of threads extending in the one direction, also include the effect of a group formation of threads extending in the other direction. Due to the crimping occurring at the tie-off points—not only of the threads extending in the other direction, but also of the threads extending in the one direction—particularly those threads extending in the other direction which are positioned between two tie-off points and which are located in the one direction at a distance to each other are pressed against each other. In other words, particularly those located between the third and the fourth tie-off points.
In order to be able to further positively utilize this group formation effect of threads extending in the other direction it is suggested that a binder thread pair is located between the threads of the second fabric layer which extend in the other direction and which form the first and the second tie-off point. In this manner the binder threads of a respective binder thread pair are tightly gathered and thereby also supported by those threads which are gathered by two or more tie-off points into groups extending in the other direction and which are then located adjacent to each other in the one direction.
The second woven fabric layer, in other words the fabric layer which also provides the contact with the various idler or drive rollers can for example be arranged so that within one field of repeat each thread of the second woven fabric layer extending in the other direction is tied off at a single thread of the second fabric layer extending in the one direction, thereby forming a tie-off point, and/or that within one field of repeat a single thread of the second woven fabric layer extending in the other direction ties off at each thread of the second woven fabric layer extending in the one direction.
It is further suggested that between two successive tie-off points in the other direction of a thread of the second woven fabric layer extending in the other direction this thread progresses on the machine side of the threads of the second woven layer extending in the one direction. In this way it can be assured that those threads of the second woven fabric layer which in the inventive arrangement can be selected with larger dimensions, in other words greater thickness, do in fact also provide the machine contact surface in essential areas.
The gathering of the threads extending in the one direction into individual groups which preferably extend completely in the one direction over the entire belt is accomplished especially efficiently in that threads of one group of the second fabric layer extending in the one direction which are pressed against each other by a group of tie-off points in the other direction are also gathered into one group by binder threads extending in the other direction.
The one direction can for example be consistent with the longitudinal direction of the belt, whereby then the other direction is consistent with the cross direction of the belt. Production technological reasons preferably further provide that the one direction is consistent with a warp direction and the other direction is consistent with a weft direction.
The current invention is explained in further detail with reference to the enclosed drawings.
The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate one embodiment of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner.
Referring now to the drawings,
In the machine side fabric layer 100 threads 2, 4, 6, 8, 10, 12, 14, 16 extend in the longitudinal MD direction of the belt. The longitudinal direction of the belt MD is also consistent with the machine direction. Likewise, threads 1, 3, 5, 7, 9, 11, 13 and 15 of the web side fabric layer 102 extend in longitudinal direction MD of the belt. For example threads T1-T8 follow each other in longitudinal direction MD of the belt in the web material side fabric layer 102 in a respective field of repeat which defines the smallest repeat unit in longitudinal direction MD of the belt and in cross direction CMD of the belt.
After each two threads T1, T2 extending in cross direction CMD of the belt in the web side fabric layer 102, and likewise two threads B1 and B2 in the machine side fabric layer 100, a pair of binder threads Bi1, Bi2, Bi3, Bi4, Bi5, Bi6, Bi7, Bi8 which are allocated to each other follows. This means that within each field of repeat there are several successive binder thread pairs Bi1-2, Bi3-4, Bi5-6, Bi7-8 located in longitudinal direction MD of the belt. In each pair of binder threads the individual binder threads change over (as shown for example in the binder thread pair Bi1-2) at the cross over points K between the web side fabric layer 102 and the machine side fabric layer 104. In the area where the respective binder threads Bi1 or Bi2 are tied into the web side fabric layer 102 they form a linen weave together with threads 1, 3, 5, 7, 9, 11, 13, 15 which extend in the longitudinal direction MD of the belt, resulting in a very finely structured web contact surface on the web material side 106. Binder threads Bi1, Bi2, Bi3, Bi4, Bi5, Bi6, Bi7, Bi8 also serve in a structure creating capacity so that each binder thread pair Bi1-2, Bi3-4, Bi5-6, Bi7-8 in the web side fabric layer 104 in fact replaces a complete thread which extends in cross direction CMD of the belt.
In the machine side fabric layer 100 threads B1, B2, B3, B4, B5, B6, B7, and B8 which extend in cross direction CMD of the belt progress essentially on a side facing the machine side 108 of the respective threads 2, 4, 6, 8, 10, 12, 14, 16 of this fabric layer 100 which extend in longitudinal direction MD of the belt. However, inside a field of repeat each of the threads B1-B8 extending in cross direction CMD of the belt ties off at a tie-off point X above one of the threads 2, 4, 6, 8, 10, 12, 14, 16 of this fabric layer 100. “Above” in this instance means that the tie-off occurs on the side facing away from the machine side 108 of a respective thread extending in longitudinal direction MD of the belt, as is indicated for example by the tie-off point X of thread B1 in
It can be seen, especially in
This results in the structure which can also be seen in
In longitudinal direction MD of the belt immediately adjacent binder thread pairs Bi1-2, Bi3-4, Bi5-6 alternate in gathering threads which extend in longitudinal direction MD of the belt into groups G1.
The result is a structure of groups G1 on threads extending in longitudinal direction MD of the belt which are represented here by threads 4, 6 or 8, 10, or 12, 14 or 16, 2 respectively (in the adjoining area of two fields of repeat). These groups G1 extend in the entire longitudinal direction MD of the belt through the field of repeat. The distance of threads which extend in longitudinal direction MD of the belt inside a respective group G1 with threads 4, 6 or 8, 10, or 12, 14 or 16, 2 is thereby smaller than the distance between the individual groups G1. These groups G1 thereby have the effect of a virtual “thicker thread” above which a respective thread B1, B2, B3, B4, B5, B6, B7, B8 extending in cross direction CMD of the belt ties off in order to form a respective tie-off point X. Despite utilization of comparatively thinner threads 2, 4, 6, 8, 10, 12, 14, 16 of the machine side fabric layer 100 which extend in longitudinal direction MD of the belt it is therefore possible to utilize comparatively thicker threads B1-B8 extending in cross direction CMD of the belt which then also provide an accordingly higher wear resistance.
As indicated in
A further contribution to the formation of individual groups G1 of threads in the machine side fabric layer 100, which in spite of comparatively thinner thread material appear as a thicker thread, is achieved by the defined positioning of the tie-off points X of threads B1-B8 which extend in cross direction CMD of the belt. Below this is explained with reference to
Here one can see two encircled groups G2 of tie-off points X which exert such forces upon threads 2, 4, 6, 8, 10, 12, 14, 16 of the machine side fabric layer 100 which extend in longitudinal direction MD of the belt that likewise threads 4, 6, or 8, 10, or 12, 14 or 16, 2 respectively are pressed against each other. In such a group G2 there are two tie-off points X1, X2 which are located on both sides of the two threads which are to be gathered into a group G1. In group G2 which is located on the right in
This explanation illustrates that each of these groups G2 of tie-off points X within one field of repeat presses two threads which extend in longitudinal direction MD of the belt and which at the same time are also gathered by a binder thread pair into a group G1 of threads extending in longitudinal direction MD of the belt against each other. The two effects generated by the binder threads and the tie-off points therefore support each other.
An additional effect caused by the provision of the tie-off points X in defined positions is that not only the formation of pairs of threads 2-16 which extend in longitudinal direction MD of the belt is supported, but also that adjacent threads B1-B8 in cross direction CMD of the belt are gathered into groups or pairs. At the left edge of
The current invention utilizes this effect in order to arrange a pair of binder threads between two such threads which extend in cross direction CMD of the belt and which form a thread group which in the previously described example is the pair formed by binder threads Bi1 and Bi2. Threads B2 and B3 which are herewith to move closer toward each other form a protection especially at the machine side 108 for the binder thread pairs gathered there so that these are subjected to a lower stress, especially in interaction with the various rolls which drive or guide a belt of this type.
It is pointed out in this context that
Also clearly recognizable in
In the previously described example of a fabric belt the longitudinal direction MD of the belt , in other words the machine direction, can be consistent with the warp direction during the manufacture of such a belt, whereas the cross direction CMD of the belt, in other words the cross machine direction, can be consistent with the weft direction. Obviously, this can also be vice versa. It must also be pointed out that the number of threads in a respective group G1 can differ from the illustrated example. However it has been shown that based on the selection of groups G1 with two threads each, the desired effect of gathering or pressing toward each other can be achieved especially efficiently, especially in conjunction with an 8-time satin weave of the machine side fabric layer 100. It is also pointed out that essentially groups G1 are oriented such that they extend in cross direction CMD of the belt.
While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.
Number | Date | Country | Kind |
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10 2008 000 088.4 | Jan 2008 | DE | national |
This is a continuation of PCT application No. PCT/EP2008/064863, entitled “A FABRIC BELT FOR A MACHINE FOR PRODUCING WEB MATERIAL, IN PARTICULAR PAPER OR PAPERBOARD”, filed Nov. 3, 2008, which is incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/EP2008/064863 | Nov 2008 | US |
Child | 12788881 | US |