EP0059483B1 - Shedding apparatus for the circular weaving of multi-harness fabrics and use of the shedding apparatus therefor - Google Patents

Abstract

A shedding apparatus for the circular weaving of multi-harness fabrics includes a plurality of heddle frames for weaving a multi-ply screen of the type suitable for use with a paper making machine. Each heddle frame has a warp wire from each fabric half drawn therethrough and a divider wire is located between the heddle frames and the reed. The divider wire extends across the entire width of the fabric with all of the warp wires of the upper fabric half extending above the wire divider and all of the warp wires of the lower fabric half extending beneath the wire divider so that upon weaving of one fabric half the divider wire is raised or lowered so that the warp wires of the other fabric half are urged away from the shed by the wire divider. A compensator rod may be provided between the heddle frames and the warp beam to compensate for the tension placed on warp wires due to different path lengths for the warp wires as caused by the wire divider.

Description

The invention relates to a shedding device for circular weaving of high-yielding fabrics according to the preamble of claim 1, as is the general state of the art.

In practice, the number of shafts of a weave is limited by the number of frames or harness frames. The number of harness frames cannot be increased arbitrarily, since the stroke of each additional harness frame would be extraordinarily large for a given angle of the compartment opening.

Especially for circular weaving looms with a high number of shafts are required, since the weft thread is pulled alternately through the upper half of the fabric and through the lower half of the fabric and therefore double the number of shafts is required, e.g. B. 14 harness frames are necessary for a seven-leg binding. The difficulties in the circular weaving of multi-layer fabrics, e.g. B. multilayer paper machine screens. For circular weaving z. B. a double-layer paper machine screen with a seven-strand binding according to conventional methods would require 28 dishes. However, modern round looms for paper machine screens have a maximum of 17 harness frames.

The invention is therefore based on the object of creating a shedding device for circular weaving of high-weave fabrics.

This object is achieved by the characterizing features of claim 1.

The invention further relates to the use of this shedding device for circular weaving of high-weave fabrics, as specified in claim 3.

The advantages that can be achieved by the invention are, in particular, that only as many harness frames are required as if the fabric were woven open, namely the number of layers times the number of warp threads of a layer per weave repeat. Since warp threads of the lower and the upper fabric half are drawn in in each dish frame, the same dish frames serve for weaving both the lower and the upper fabric half. The application of the invention is not limited to double-layer or multi-layer sieves, but also relates to single-layer round-woven fabrics.

• Fig. 1 den Einzug der Kettfäden in die Geschirrahmen und den Verlauf der Kettfäden über und unter dem Fadenteiler;
• Fig. 2 den Durchzug eines bestimmten Schußdrahtes durch die obere Gewebehälfte;
• Fig.3dieStellungderGeschirrahmenbeidemin Fig. 2gezeigten Durchzug eines Schußdrahtes;
• Fig.4 den nachfolgenden Durchzug des Schußdrahtes durch die untere Gewebehälfte, d. h. den Rückweg des in Fig. 2 gezeigten Schußdrahtes;
• Fig. 5 die Stellung der Schaftrahmen bei dem in Fig. 4 gezeigten Durchzug des Schußdrahtes durch die untere Gewebehälfte;
• Fig. 6 den nachfolgenden Durchzug des Schußdrahtes durch die obere Gewebehälfte;
• Fig. 7 die Stellung der Schaftrahmen bei dem in Fig. 6 gezeigten Durchzug des Schußdrahtes;
• Fig. 8 den Durchzug eines bestimmten Schußdrahtes beim Weben eines dreilagen Gewebes;
• Fig. 9 die Stellung der Geschirrahmen bei dem in Fig. 8 gezeigten Durchzug eines Schußdrahtes;
• Fig. 10 eine Ausführungsform des Fadenteilers für besonders breite Webmaschinen, wie sie für Papiermaschinensiebe benötigt werden;
• Fig. 11 den Verlauf der Kettfäden vom Webeblatt bis zur Zettelwalze;
• Fig. 12 den Geschirreinzug bei zusätzlicher Verwendung eines Kompensators und
• Fig. 13 und 14 die Stellung des Kompensators in Abhängigkeit von der Stellung des Fadenteilers.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawing. It shows

• 1 shows the insertion of the warp threads into the harness frame and the course of the warp threads above and below the thread divider.
• Figure 2 shows the passage of a particular weft wire through the upper half of the fabric.
• 3 shows the position of the harness frame in the passage of a weft wire shown in FIG. 2;
• 4 shows the subsequent passage of the weft wire through the lower half of the fabric, ie the return path of the weft wire shown in FIG. 2;
• 5 shows the position of the shaft frame in the passage of the weft wire through the lower fabric half shown in FIG. 4;
• 6 shows the subsequent passage of the weft wire through the upper half of the fabric;
• 7 shows the position of the shaft frame in the passage of the weft wire shown in FIG. 6;
• 8 shows the passage of a specific weft wire when weaving a three-layer fabric;
• FIG. 9 shows the position of the harness frames in the passage of a weft wire shown in FIG. 8;
• 10 shows an embodiment of the thread divider for particularly wide weaving machines, as are required for paper machine sieves;
• 11 shows the course of the warp threads from the reed to the carding roller;
• Fig. 12 the harness retraction when using a compensator and
• 13 and 14 the position of the compensator depending on the position of the thread divider.

In the embodiment of the invention shown in the drawing, a double-layer paper machine screen is woven in a seven-strand weave of the longitudinal wires (= weft wires). For this purpose, the shed forming device has 14 harness frames, which have two strands per binding repeat of the chain, namely one strand for each binding repeat of the upper and lower sieve halves 25 and 26. The harness frames therefore contain twice the number of strands 24 as usual. Instead, however, each strand can also have two strand eyes or two warp threads can be passed through one strand eye. In front of the first harness frame 1, ie between the harness frame 1 and the weaving reed 27, a thread divider 20 is arranged, which in the simplest case consists of a rod that extends over the entire width of the weaving machine. The thread divider 20 is displaceable between an upper and a lower position and is in its upper and lower position at the edge of the opening angle of the compartment. With each change of subject it is moved from one position to the other position, e.g. B. by pneumatic, hydraulic, other mechanical or electromagnetic devices that essentially correspond to the devices that are used to raise and lower the harness frame 1 to 14. As can be seen in Fig. 1, the warp threads shown in the drawing by a continuous line of the upper half of the sieve 25 are drawn in such that they run over the thread splitter 20 and the warp threads of the lower half of the sieve 26 shown by a broken line are drawn in such that they run under the thread divider 20. In its low position, the thread divider 20 therefore presses down all the warp threads of the lower half of the sieve 26, including those warp threads that are raised by a Dish frame run. Conversely raises the yarn divider 20 in its high position, all warp threads of the upper Siebhä _l RTD 25, and even those that pass through a straight lowered heald frames.

In Fig. 2, the 28 warp threads of the selected embodiment are shown in section as small circles, the warp threads of the upper two lines are numbered from 1 to 14 and belong to a weave repeat of the upper half of the screen 25, while the warp threads of the lower two lines are numbered 1a to 14a are numbered and belong to a weave repeat of the lower half of the sieve 26. The warp threads of a row each belong to a specific position of the fabric. If a weft thread 28 is to be pulled through as shown in FIG. 2, the corresponding harness frames are raised or lowered as shown in FIG. 3, with the warp wires 1 and 1a of FIG. 1 through the harness frame 1 of FIG. 3 run, the warp wires 2 and 2a of FIG. 2 run through the harness frame 2 of FIG. 3, etc. A warp thread of the upper 25 and a warp thread of the lower sieve half 26 are thus alternately drawn into each harness frame. 2, the weft wire 28 is to run over the warp threads 1 to 4, 6, 8, 12 and 14, these harness frames are lowered in FIG. 3, while the other harness frames are raised, since the weft wire 28 runs under the corresponding warp threads should. The warp threads 5a, 7a, 9a, etc. of the lower half of the sieve 26 run through the harness frames 5, 7, 9 etc. raised in FIG. 3, but the weft wire 28 does not run under these warp wires, since the thread divider 20 in FIG. 3 is in its deep position, so that all the warp wires of the lower Siebhä _l fte 26 are pressed down and the weft wire 28 runs over all the warp wires of the lower half of the sieve 26.

4 and 5 show the subsequent passage of the weft wire 28 through the lower half of the sieve or the position of the harness frame and the thread divider 20 here. The compartment is now formed in the lower Siebhä _l fte 26 according to the desired course of the weft wire 28. The thread divider 20 is in its high position and thus presses all the warp threads of the upper Siebhä _l fte 25 upwards, so that the weft wire 28 inevitably runs under all the warp wires of the upper sieve half 26.

As usual, the circular weaving, the weft wire 28 is now forces back to the upper Siebhä _l entered the 25th In the exemplary embodiment chosen here, the weft wire 28 should run as shown in FIG. 6, for which purpose the position of the harness frame shown in FIG. 7 is necessary. The thread divider 20 is again in its deep position and presses all the warp threads of the lower half of the sieve 26 downwards. The thread divider 20 is thus in its deep position when the weft thread is inserted into the upper fabric half 25 and is in its high position when the weft thread is inserted into the lower fabric half 26.

The weaving of a three-layer or generally a multi-layer fabric is carried out in exactly the same way as described for double-layer fabrics. Each harness frame is equipped with twice the number of strands - one half of the strands for the upper fabric half 25, the other half of the strands for the lower fabric half 26.

Fig. 8 shows the passage of a weft wire 28 when weaving a three-layer fabric. Only the warp wires 2, 3, 4 and 7 are pulled up over the corresponding harness frames and form the upper side of the shed. The remaining warp wires form the lower side of the compartment opening 22 when the weft wire 28 is pulled through. The position of all the harness frames is shown in FIG. 9. The thread divider 20 presses all the warp wires that are only required when weaving the lower fabric half 26 downward outside the compartment opening 22. In this way, the warp wires 2a, 3a, 4a and 7a of the above harness frames are displaced from the compartment opening 22.

In the drawing, the thread divider 20 is shown with a round cross section. However, it expediently has an oval cross section, the long axis being vertical, in order to give the thread divider 20 stability in the vertical direction and to prevent bending as far as possible. With very wide weaving machines, such as B. are used for weaving paper machine screens, the thread splitter 20 is preferably mounted within a stable support frame, as shown in Fig. 10. The carrier frame surrounds the shed and the thread divider 20 is held in the carrier frame by steel wires or the like. The carrier frame moves with a thread divider up and down with each change of subject.

11 shows the entire course of the warp threads from the warping roller via the shedding device, the weaving reed 27 (weaving point) to the fabric tree. It can be seen here that the path described by the individual warp threads is of different lengths, the path being the longest of those warp threads that run through the deep harness frames when the thread divider 20 is raised. Since the thread divider 20 assumes the opposite position each time the shed is changed, it can happen that other warp wires describe the longest path after the next shed change. The different lengths of the paths described by the individual warp threads can lead to differences in tension in the individual warp threads.

These tension differences can be compensated for by the compensator 30 shown in FIGS. 12 to 14, which largely corresponds in construction to the thread divider 20, but is arranged behind the last harness frame, ie between this harness frame and the warping roller. As shown in Fig. 12, the warp wires are drawn in so that the Warp wires of the lower half of the screen 26, which run under the thread divider 20, are also drawn in under the compensator 30. The warp threads of the upper half of the sieve 25, which run over the thread divider 20, are also guided over the compensator 30. As shown in FIGS. 13 and 14, with this guiding of the warp threads, the compensator 30 is moved in opposition to the thread divider 20, ie when the thread divider 20 is in its high position, the compensator 30 is in its low position and vice versa.

The warp threads can also be guided in such a way that the warp threads that run over the thread splitter 20 are passed under the compensator 30 and vice versa. The compensator 30 is then raised and lowered not in push-pull, but in time with the thread divider 20.

It should also be pointed out that the path length differences of the individual warp threads are exaggerated in FIGS. 11 to 13 for clarification. The differences in length between the normal warp wires and the warp threads pressed by the thread splitter 20 to the edge of the shed are actually smaller than shown in the drawing. In addition, all the wires involved in the current weaving process have the normal course. Only the warp threads pushed away by the thread divider 20, which only take part in the weaving process again after the change of subject and the normalization of the tension conditions, are tightened more.

Claims (3)

1. Shedding apparatus for circular weaving of multi-harness fabrics comprising a plurality of heddle frames movable up and down in accordance with a desired weave, characterized in

that a wire divider (20) in the form of a rod extending across the entire fabric width is disposed between the first heddle frame (1) and the weaving location and

that means are provided which lift and lower said wire divider (20) upon each shed change, said wire divider (20) being disposed in its extreme upper and lower positions outside of or at the most adjacent the border of the shed opening (22).

2. Shedding apparatus according to claim 1, characterized by a tension compensator (30) in the form of a rod extending across the entire fabric width and means which lower and, respectively, lift said tension compensator (30) in phase opposition to said wire divider.

3. Use of the shedding apparatus according to claims 1 or 2 for circular weaving multi-harness fabrics characterized in

that each heddle frame (1-14) carries a warp thread of the upper fabric half (25) and of the lower-fabric half (26) per repeat of the weaving pattern with all of the warp threads of the upper fabric half (25) extending above said wire divider (20) and all of the warp threads of the lower fabric half extending below said wire divider, and in

that, during weaving of the one fabric half, the warp threads of the respective other fabric half are pushed away by the wire divider (20).

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