EP1008683B1 - Method for compensating the change in length and tension in the warp and loom for carrying out the method - Google Patents

Abstract

The warp is divided into different sections (3a,3b,3c) corresponding to the weaving pattern in the fabric. An oscillating backrest (2), which compensates for tension variations arising from the shed motion, has modules (4,5,6) which provide independent compensation for the different sections. An Independent claim is also included for a loom with a driven oscillating backrest (2) with at least one module (4) with a surface (4a) to provide compensation for part (3b) of the warp. The module is cam-shaped and attached to the surface (2b) of the backrest

Description

The invention relates to methods for compensating the change in elongation or tension in a warp and weaving machine to carry out the method according to the features the preamble of claims 1 and 6.

In the manufacture of fabrics on weaving machines, the weaving chain is subject to in the course of Different warp tension fluctuations that occur when the fabric is open Shed for the purpose of weft insertion and beating a maximum value and a minimum value for the so-called subject change. This alternating load in the The warp leads to a relatively high warp thread stress, the cause of Warp thread breaks is.

The low warp tension that occurs when changing the shed can impair the reopening of the shed due to the jamming of warp threads. These brackets are also frequently the cause of warp thread breaks and, in the case of weaving machines with pneumatic weft thread insertion, the cause of so-called weft folds.
The above-mentioned problem is solved in weaving machines with closed shed formation or plain weave by means of a match tree which is fixedly or rotatably mounted in rocking levers and which performs controlled or uncontrolled periodic movements to compensate for the warp tension during the change of shed, as for example in DE 32 16 903 C2, DE 35 32 798 C2 and EP 0 409 306 A1.

When producing a fabric in which, for example, the fabric edges have a weave that is different from the rest of the fabric, the problem of load changes in the chain becomes even clearer.
If, for example, the fabric edges are to have a 2/2 weave in order to produce a stable fabric edge, and the fabric itself should have a plain weave, i.e. a 1/1 weave, the relevant edge warp threads are between the change of subject, i.e. between the open subject and the Closed compartment, exposed to greater warp tension fluctuations than the other warp threads. In the event of a change of subject, the aforementioned phenomena which disrupt the weaving process occur in particular in the relevant warp threads of the warp.

A weaving machine is known from DE 26 59 530 A1, in which the match tree is set up to carry out a certain translational movement in order to compensate for the tension variations in the warp threads guided over the match tree, which variations are caused by the successive change of subject.
In addition, an auxiliary guide for a number of edge warp threads is provided in the vicinity of at least one end of the match tree, which can carry out a translational movement independently of the match tree under the influence of an adjustable load acting thereon.
This auxiliary device can easily follow the successive change of subject, so that the tension fluctuations in the relevant warp threads can be considerably reduced.
It is obvious that the tension compensation device assigned to the match tree and the auxiliary device assigned to the edge warp threads represent a not inconsiderable cost factor for the manufacturer of the weaving machine.

It is therefore the object of the invention, while avoiding the aforementioned disadvantages, to take precautions to compensate for the tension in a warp that is comparatively reduced in the course of a change of subject, in order to achieve a stable warp tension state in the warp threads, in particular in the production of a fabric which should have different weaves.
Furthermore, it is an object of the invention in weaving machines which are equipped with a modular match tree to dispense with an article-related retooling of the weaving machine to compensate for the elongation or tension change in the weaving chain.

The object is achieved by the features of claims 1 and 6.
Thereafter, the match beam, which is rotatably mounted in a weaving machine, is equipped with at least one first module in such a way that this is adjusted in rhythm with the change of subject about its longitudinal center axis and the module compensates for the lower warp thread tension.
According to the invention, the module of the match tree consists of at least one first component which can be arranged on the lateral surface and over the working width of the match tree and forms a cam. When changing the shed, the module is effective on the warp in order to bring about elongation or tension compensation, which is a weave that is uniform across the width of the weave.

The first cam-like module arranged on the match tree can be connected to the lateral surface of the match tree several times, for example via screw connections. The first module has an arcuate recess with a radius r ₁ , which corresponds to the diameter radius of the match tree, while the free outer surface of the module has a radius r ₂ that differs from the radius r ₁ .
In order to enable elongation or warp tension compensation in the event of a change of subject, the match tree is rotatably received on both sides with its bearing journals in a bearing in a manner known per se and, for the transmission of an oscillating movement resulting from the formation of tissue, is arranged in a rotationally fixed manner with at least one near a bearing journal of the match tree Lever arm connected. Means act on the lever arm, which transmit the aforementioned oscillating movement from a drive means of the weaving machine to the match tree. The match tree is positively controlled in this case.
Forced control of the match is given in a manner known per se when the rotation of the match is derived from the main shaft of the weaving machine, or when the match is rotated independently of the main shaft drive, for example by means of an electromotive drive interacting with the match.
In another case the match tree can be spring loaded.

If, for example, a fabric is to be produced whose edges have a weave that deviates from the rest of the weave, or if further sections with a weave, such as those that have the edges of the fabric, are to be made over the width of the fabric, the invention provides for second or third modules to connect with the match tree, via which modules the relevant warp threads are guided as a separate warp thread group.
Such a second or third module encompasses the same by pushing it onto the first module and is operatively connected to the first module in a rotationally fixed manner via its inner contour.
In a further embodiment of the invention, it is provided that an uncontrolled oscillating movement is optionally provided for the positively controlled, oscillating movement about the longitudinal center axis of the modular match tree, the positively controlled movement always being dominant over the uncontrolled movement.
If the match tree is not to be operated in a positively controlled manner when weaving a specific article, the force control is decoupled from the modular match tree in a simple manner. The match tree is then only under the action of at least one spring.
On the other hand, if the match tree is to perform a positively controlled, oscillating movement, the match tree can also be spring-loaded, but the forced control is dominant over the spring load.

• Reduzierung der Kettfadenbeanspruchung und im Zusammenhang damit Reduzierung der Anzahl von Kettfadenbrüchen,
• Erhöhung der Reissfestigkeit des Gewebes im Randbereich,
• Erhöhung des Dichtegrades des auf der Webmaschine herstellbaren Gewebes,
• Verbesserung des Handlings und
• reduzierter Montageaufwand bei Artikelwechsel.

The following advantage is achieved with the solution according to the invention:

• Reduction of the warp thread stress and in connection therewith reduction of the number of warp thread breaks,
• Increase the tear strength of the fabric in the edge area,
• Increasing the degree of density of the fabric that can be produced on the weaving machine,
• Improvement of handling and
• reduced assembly effort when changing articles.

The invention is to be illustrated in more detail below using an exemplary embodiment.

Figur 1

die Vorderansicht der Einheit Kettbaum-Streichbaum mit modularen Aufbauten;

Figur 2

die Seitenansicht der in Figur 1 dargestellten Einheit nach Ansicht A mit gesteuerter Bewegungsübertragung auf den Streichbaum;

Figur 3

den Streichbaum in perspektivischer Darstellung mit modularen Aufbauten;

Figur 4

den Streichbaum mit modularen Aufbauten nach Ansicht B gemäß Figur 3;

Figur 5

eine Schnittdarstellung des Streichbaumes nach Linie A-A gemäß Figur 4;

Figur 6

die Seitenansicht eines modular aufgebauten Streichbaumes sowohl mit Mitteln zur zwangsweisen als auch mit Mitteln zur zwangslosen, oszillierenden Bewegung um dessen Längsmittenachse.

The drawings show:

Figure 1

the front view of the warp beam-matchbox unit with modular structures;

Figure 2

the side view of the unit shown in Figure 1 according to view A with controlled movement transfer to the match tree;

Figure 3

the match tree in perspective with modular structures;

Figure 4

the match tree with modular structures according to view B of Figure 3;

Figure 5

a sectional view of the match tree along line AA of Figure 4;

Figure 6

the side view of a modular match tree, both with means for forced and with means for casual, oscillating movement about its longitudinal central axis.

FIGS. 1 to 5 show the parts of a weaving machine that relate directly to the invention.
FIG. 1 shows a warp beam 1 wound with a plurality of warp thread groups 3a, 3b, 3c, which is rotatably supported in the weaving machine in the direction of rotation indicated by the arrow 8 about its longitudinal central axis 1a and a match beam 2 which is rotatably supported in the weaving machine about its longitudinal central axis 2a is and has modular structures, hereinafter referred to as modules 4,5,6.
The match tree 2 carries the modules 4, 5 and 6 over its working width L, best seen in FIG. 3.
In the present example, modules 5 and 6 each lead a first warp thread group 3a or 3c in the direction of the heald frames, not shown, to form a stable fabric edge, the fabric edge having, for example, a 2/2 weave, while a second warp thread group 3b extends over the outer surface 2b of the match tree 2 is guided in the direction of the heald frames, not shown.
While the warp threads of the first warp thread group 3a and 3c are now guided with a much larger wrap angle via the modules 5 and 6 in the direction of the heald frames and are accordingly pre-tensioned, i.e. still have a sufficiently high warp tension when changing the shed, the warp tension in the warp threads changes when the shed is changed the second warp thread group 3b considerably.
In order to avoid a drastic change in warp tension in the second warp thread group 3b, it is further provided according to the invention that when the shed is changed, the second warp thread group 3b experiences a compensation of the warp tension synchronously by the module 4 of the match tree 2. For this purpose, according to FIG. 2, the match tree 2 is connected in a manner known per se via a motion transmission mechanism 9 to an eccentric 10 arranged on the main shaft 7. With each change of subject, the desired warp thread tension in the warp thread group 3b is thus largely maintained via the module 4.
The motion transmission mechanism 9 consists of a first lever arm 9a connected in a rotationally fixed manner to the match tree 2, a pivotably mounted double lever 9b, the first lever arm 9b 'of which is connected to the eccentric 10 arranged on the main shaft 7 and the second lever arm 9b "of which the lever 9a, 9b connecting coupling 9c is articulated.

Figure 3 shows the match tree 2 with the modules 4,5,6 according to the invention, the first Module 4 on the lateral surface 2b of the match tree 2 over its working width L is arranged. The connection of the module 4 to the lateral surface 2b can be done in many different ways. The type of connection is not an issue the invention.

The arrangement of the module 4 on the match tree 2 is clearly shown in Figure 4. It is important here that the free lateral surface 4a of the module 4 has a radius r ₂ which is significantly smaller than the radius r _{1 of} the match tree diameter. The module 4 is thereby designed in the manner of a cam which is connected to the match tree 2 on the lateral surface 2b.

FIGS. 3 and 4 also show a second and third module 5, 6 or a module 5 which is designed in the manner of a segment cut out of a closed U-profile ring. The inner lateral surface of the modules 5, 6 has a contour which corresponds to the outer contour which arises from the modular connection of the match tree 2 to the module 4.
Thus, while the module 4 is non-rotatably connected to the match tree 2 by means known per se, the further modules 5, 6 are non-rotatably connected to the module 4.
It goes without saying that the modules 5 and 6 can be secured against an axial displacement on the match tree 2.
In the present exemplary embodiment according to FIG. 5, within the u-profile-like warp thread guide 5a, 5b, 5c; of the modules 5 and 6a, 6b, 6c of the modules 6 a first or a second group of edge warp threads 3a or 3b are taken up, which do not require an elongation or warp tension compensation, for example due to the type of weave provided for the fabric edge area, while that between the modules 5.6 warp thread group 3b guided over the match tree 2 requires such compensation when the subject is changed.
The design of the u-profile warp thread guide of the modules 5, 6 concerned can be left to the person skilled in the art.
It is therefore essential to the invention that a match tree 2 with modular structures 4, 5, 6 was created, which realizes elongation and tension compensation in at least the warp thread group 3b when the subject is changed.

FIG. 6 shows a warp beam 1 wound with a plurality of warp thread groups 3a, 3b, which is rotatably supported in the weaving machine in the direction of rotation indicated by the arrow 8, and a match beam 2, which is likewise rotatably supported in the weaving machine about its longitudinal center axis 2a.
Furthermore, the match tree has 2 modular structures 4,5. In the present example, a first warp thread group 3a is guided over the module 5, while a second warp thread group 3b is guided over a section of the lateral surface of the match tree 2 in the direction of the heald frames, not shown.
While the warp threads of the first warp thread group 3a, which can be, for example, edge warp threads of a fabric to be produced, are guided over the module 5 with a much larger wrap angle and are accordingly pretensioned, i.e. still have sufficient warp tension when changing the shed, the warp tension in the warp threads changes when the shed is changed the second warp thread group 3b considerably.
In order to counteract a drastic change in warp tension in the second warp thread group 3b, it is provided that when the shed is changed, the second warp thread group 3b experiences a compensation of the warp tension synchronously by the module 4 of the match tree 2. For this purpose, according to the figure, the match tree 2 is connected in a manner known per se either via a motion transmission mechanism 9 to an eccentric 10 arranged on the main shaft 7 or the match tree 2 is operatively connected to at least one spring 11 which compensates for the warp tension. As a result, the desired warp tension in the warp thread group 3b is largely maintained with each change of subject via the module 4.
In order to dispense with an article-related retrofitting of the means compensating the warp tension according to the task, the modular match tree 2 according to the invention is available both with the means 7, 9, 10 for executing a positively controlled oscillating movement about its longitudinal central axis 2a and with at least one means 11 Execution of an uncontrolled oscillating movement in operative connection, the means used for the forced control of the match tree 2 suppressing in their effect the means for uncontrolled application of the match tree. If the match tree 2 is to be loaded only by the uncontrolled means, that is to say by the at least one spring 11, then the means for positive control are decoupled from the match tree 2 in a simple manner.

DRAWING LEGEND

01

warp beam

01a

Longitudinal central axis

02

back rest

02a

Longitudinal central axis

02b

lateral surface

03a

warp thread

03b

warp thread

03c

warp thread

04

module

04a

lateral surface

05

module

06

module

07

main shaft

08

arrow

09

Motion transmission mechanism

09a

lever arm

09b

double lever

09b '

lever arm

09b "

lever arm

09c

paddock

10

eccentric

11

spring element

r ₁

Radius match diameter

r ₂

Radius module

r ₃

Radius warp thread guide

r ₄

Radius profile leg

L

Back rest length

Claims (14)

1. Method for compensating for the change in extension or tension in the warp guided by a warp beam over an oscillating back rest roller mounted in a loom so as to rotate about is longitudinal centre line, during production of a woven fabric that has at least a first and/or at least a second type of weave, characterised in that

   in preparation for a weaving process, the warp is guided in the form of at least a first and/or second warp thread group over modules separately connectible to the back rest roller and

   during the weaving process the change in extension or tension of the at least first warp thread group is compensated for independently of the change in extension or tension of the other warp thread groups.
2. Method according to claim 1, characterised in that the change in extension or tension of the at least first warp thread group is compensated in that the oscillating movement derived from a drive means is transferred to the back rest roller equipped with the separate modules.
3. Method according to claim 2, characterised in that the drive means is the main drive shaft of the loom.
4. Method according to claim 2, characterised in that the drive means is a drive means independent of the main drive means.
5. Method according to claim 1, characterised in that the change in extension or tension of the at least first warp thread group is compensated in that the back rest roller equipped with the separate modules is subject to spring action.
6. Method according to claim 1, characterised in that the change in extension or tension of the at least first warp thread group is compensated in that a non-positively driven oscillating back rest roller movement underlies the positively driven, oscillating movement of the back rest roller.
7. Method according to claim 6, characterised in that the positively driven back rest roller movement overrides the non-positively driven back rest roller movement.
8. Loom for carrying out the method according to claim 1, having a rotatably mounted back rest roller (2) over which a warp (3a, 3b, 3c) coming from at least one warp beam (1) is guided to produce a woven fabric, having means (7, 9, 10) that transfer an oscillating movement to the back rest roller (2), and wherein the woven fabric to be produced has a first and/or at least a second type of weave, characterised in that the back rest roller (2) is equipped across its working width (L) with at least a first module (4) for extension compensation or tension compensation in the warp (3b).
9. Loom according to claim 8, characterised in that the first module (4) is arranged in the manner of a cam on the lateral surface (2b) of the back rest roller (2).
10. Loom according to claims 8 and 9, characterised in that at least a second module (5) is constructed in the manner of a cam which engages completely around the free lateral surface (4a) of the first module (4) and engages partially around the lateral surface (2b) of the back rest roller (2).
11. Loom according to claims 8 and 9, characterised in that the first module (4) is connected to the back rest roller (2) so that they rotate together and further modules (5, 6) are connected to the first module (4) so that they rotate together.
12. Loom according to claim 8, characterised in that the first module (4), together with the back rest roller (2), forms a larger contact angle for the warp (3b) that the lateral surface (2b) of the back rest roller (2) alone, and in that the second module(5) forms larger contact angle compared with the back rest roller (2) and the first module (4) together.
13. Loom according to claim 8, characterised in that, in addition to the means (7, 9, 10), at least one spring element (11) is operatively connected with the back rest roller (2).
14. Loom according to any one of claims 8 to 13, characterised in that either the means (7, 9, 10) or the spring element (11) can be disconnected from the movement transfer.

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