CN109642363B

CN109642363B - Method and device for changing dynamic behavior of back beam of loom

Info

Publication number: CN109642363B
Application number: CN201780053863.7A
Authority: CN
Inventors: M.菲比希; M.吉伦; D.奥伯迈尔
Original assignee: Lindauer Dornier GmbH
Current assignee: Lindauer Dornier GmbH
Priority date: 2016-09-02
Filing date: 2017-08-10
Publication date: 2021-06-25
Anticipated expiration: 2037-08-10
Also published as: TW201812129A; WO2018041592A1; EP3507405A1; EP3507405B1; JP2019529730A; CN109642363A; DE102016216610B3

Abstract

The invention relates to a method for changing the dynamic behavior of a backrest beam of a weaving machine and a weaving machine having a backrest beam, wherein the backrest beam comprises at least one deflection element (2) for deflecting a warp thread (1), wherein the deflection element (2) is connected to the weaving machine via one or more spring elements in such a way that, when a force is applied to the deflection element (2) via the warp thread (1), inertial and spring forces become effective (2) on the deflection element. The effective inertial mass on the deflection element (2) is varied in order to adapt the dynamic behavior of the backrest beam to changing weaving conditions, and parts of the deflection element (2) or parts connected to the deflection element (2) are replaced, removed or supplemented.

Description

Method and device for changing dynamic behavior of back beam of loom

Technical Field

The invention relates to a method for changing the dynamic behavior of a backrest beam (Streichbalken) of a weaving machine, and a weaving machine with a backrest which is suitable for carrying out the method.

Background

With regard to weaving machines, devices for deflecting warp threads are known in the prior art, which are referred to as backrest beams, backrest rollers or whip rollers.

This device is shown, for example, in DE 102006061376 a 1. This relates to a backrest beam for a weaving machine, wherein warp movements in the warp direction are compensated or equalized by means of a thread deflection element which is pivotably arranged on a mass-optimized leaf spring.

In this respect, in the prior art, the mentioned quality optimization is intended to configure or embody the dynamic behavior of the backrest beam at high weaving speeds in such a way that the smallest possible warp tension is produced. This is achieved by the small inertial mass of the thread deflection element and the small inertial mass of the leaf spring.

WO 2012031802 a2 describes a backrest beam for guiding warp threads, which has a deflection element which is supported or supported via elastic elements on the weaving machine. Also described herein are objects or targets to provide as little inertial mass as possible on the thread deflecting element in order to keep warp loads or stresses small.

DE 1138715 a discloses a backrest beam which is rotatably supported in a tension lever which is pivotable about a fixed axis on the machine frame and which serves to press the tension beam against a warp thread under the influence of a force store. In this respect, at least one backrest beam bearing in the tension rod comprises a braking device for damping oscillations in the autorotation and pivoting movement of the backrest beam simultaneously. In this way, the dynamic behavior of the backrest beam is adjusted by changing the leverage ratio or relationship.

In using this backrest beam arrangement, it has been found that as little warp loading as possible is not reasonable or appropriate for all weaving conditions or requirements and for all fabrics. In particular in technical fabrics with a high weft density or weft group, i.e. with a large number of weft threads in a given length of fabric, it has been shown that a higher warp thread tension or warp thread tension is advantageous at least at some stage of the weaving process. This is the phase in which the weft thread is beaten up after its insertion into the shed of the weaving machine by means of a weaving reading for the edge or interlacing point of the fabric already present. If a high weft density is to be achieved, i.e. a large number of weft threads in a given length of fabric, a higher warp thread tension or warp thread tension is more advantageous at least during reed beating up, because then the interlacing point recedes less when a new weft thread is beaten up against the interlacing point by the weaving reed. This achieves that the successive weft threads lie very closely against one another in the fabric.

On the other hand, the warp thread tension in other stages of the weaving process should not be unnecessarily high, as has already been explained in detail in the prior art. This involves first the phase of shed change, which occurs between two reed picks. In this respect, depending on the pattern of the fabric, a change of all or several warp threads from the upper shed into the lower shed and vice versa takes place. In this shed variation, the warp threads run geometrically off their straight line or extend through the weaving machine. This deflection is achieved by the weaving heddle pushing the warp threads vertically upwards or downwards. The warp threads are thereby loaded or stressed by the friction forces in the heddle. In order to avoid a thread break, it is advantageous if the smallest possible warp tension is present during this shed change.

It is therefore evident that it is advantageous to temporarily generate a higher warp tension in a short time, at least during reed beating-up of some fabrics, while for other fabrics it is also reasonable and suitable to operate at a small warp tension during reed beating-up.

The aim is therefore to be able to operate with different warp tensions adapted to the type of fabric, for different fabric types, at least during reed beating-up of the weaving machine.

Disclosure of Invention

This object is achieved by a method and a weaving machine according to the independent claims.

The method for changing the dynamic behavior of a backrest beam of a weaving machine relates to a backrest beam having at least one deflection element for deflecting warp threads. The deflection element can, for example, consist of a continuous, through-bent metal plate, the longitudinal axis of which extends transversely to the direction of the warp threads. The warp threads are usually guided from a warp beam onto a deflecting element of a backrest beam to a shed-forming element of the weaving machine. Of course, instead of a single deflecting element, a plurality of deflecting elements distributed over the width of the weaving machine is also possible — for example a plurality of sheet-metal elements adapted to the weaving width.

The deflecting element is connected to the frame of the weaving machine via one or more spring elements in such a way that the inertial and spring forces are effective on the deflecting element when a force is applied or imposed that causes an acceleration or movement of the deflecting element relative to the frame. During operation of the weaving machine, an acceleration force is exerted on the deflection element by the warp threads. The inertial forces are primarily forces due to the acceleration of the inertial mass of the deflecting element. The inertial mass may also comprise further structural components which are fixed to the deflection element or are connected thereto in such a way that they also move with the deflection element during its movement or deflection.

The spring force is generated by the deflection element with the associated spring element deflecting from a rest position into a deflected position. This deflection out of the rest position into the deflection position usually already occurs as a result of the warp threads guided under tension on the deflection element. For example, a leaf spring is used as the spring element, which leaf spring is supported at one end thereof on the frame of the weaving machine and which leaf spring carries the deflection element at the other end thereof. However, arrangements are also conceivable in which the deflection element is movably supported on the chassis, for example in an articulated joint, whereby a spring element is additionally provided between the deflection element and the chassis, so that one end of the spring is deflected during deflection of the deflection element. As springs, leaf springs, torsion springs, helical coil springs or air springs are considered.

The invention is characterized in that the effective inertial mass is varied during the acceleration of the deflection element in order to adapt the dynamic behavior of the backrest beam to different weaving conditions or requirements. This occurs in such a way that parts of the deflecting element or other components connected to the deflecting element are replaced, removed or supplemented.

By means of the change in the inertial mass of the deflecting element, the dynamic behavior of the backrest beam during short jerky acceleration, for example during reed beating-up, is influenced more strongly than during slow processes, more like acceleration processes of sinusoidal propulsion, for example during shed changes.

This is particularly important for achieving a higher resistance of the deflecting element for achieving a higher warp tension during reed beating up without unnecessarily increasing the warp tension in the shed variation range; that is to say the warp threads are more stressed during shed changes.

In fabrics with less high weft density, by reducing the effective inertial mass, in the opposite sense, the warp loads or stresses can be kept small over the entire weaving cycle (reed beat-up and shed change), since lighter deflection elements resist the acceleration process with less resistance.

Thus, in a first method embodiment, when the weaving machine is switched from a fabric with a lower weft density to a fabric with a higher weft density, an increase of the effective inertial mass of the deflecting element by replacement or supplementation of parts is provided.

The increased inertial mass achieves a greater resistance of the deflecting element against jerky movements. This results in a temporarily higher warp tension in the warp during a jerk-reed beat-up of the weaving machine. These temporarily higher warp tensions during reed beating-up are a prerequisite for producing a fabric with a higher weft density.

In a second method embodiment, when the weaving machine is converted from a fabric with a higher weft density to a fabric with a lower weft density, a reduction of the effective inertial mass of the deflecting element by replacing or removing parts is provided. The reduced inertial mass achieves a lower resistance of the deflecting element against jerky movements. This has the result that, during reed beating-up of the weaving machine, lower warp tensions now occur than before and therefore less warp stresses occur therewith.

Even small differences in the effective inertial mass on the deflection element, differences in the dynamic behavior of the backrest beam have occurred. However, it is advantageous if the effective inertial mass is increased or decreased by a factor between 1.5 and 8, preferably by a factor between 2 and 5, for example 2.5 or 3 or 4. Dynamic behavior accommodates a wide range of requirements, such as: the weft density or the rotational speed, in the respective appropriate step, has various additional or supplementary qualities.

Another aspect of the invention relates to a weaving machine having a backrest beam with at least one deflection element for deflecting warp threads. The deflection element is connected to the weaving machine by one or more spring elements in such a way that, when forces and movements are applied or imposed via the warp threads, the inertial and spring forces become effective on the deflection element. During operation of the weaving machine, this acceleration force is exerted by the warp threads on the deflection element.

The inertial forces are primarily forces due to the acceleration of the inertial mass of the deflecting element. Other components fixed to the deflection element can also belong to the inertial mass.

The spring force is generated as a result of the deflection element with the associated spring element out of the rest position into the deflected position. This deflection from the rest position into the deflected position is usually effected by warp threads which are guided under tension on the deflecting element. As spring element, for example, a leaf spring can be used, which is supported or supported on one end on the frame of the weaving machine and which carries the deflection element on its other end. However, arrangements are also conceivable in which the deflection element is movably supported on the frame, for example in an articulated joint, whereby furthermore an elastic element is arranged between the deflection element and the frame in such a way that, upon deflection of the deflection element, one end of the spring is also deflected. As springs, leaf springs, torsion springs, helical coil springs or air springs are considered.

The weaving machine according to the invention is characterized in that the effective inertial mass of the deflection element is variable in order to adapt the dynamic behavior of the backrest beam to different weaving conditions or requirements. This variability is achieved by: the parts of the deflection element or parts connected to the deflection element are embodied as replaceable, removable or replenishable.

It has been shown to be particularly advantageous if various deflection elements or complementary masses are kept in place, with which the effective inertial mass of the deflection element can be increased or decreased by a factor of between 1.5 and 8, preferably by a factor of between 2 and 5, for example 2.5 or 3 or 4.

As a starting point or basis for the weaving machine according to the invention, an embodiment has proved suitable in which the deflection element is embodied as a bent metal sheet. As has been shown in the prior art, with this metal plate a very low-mass deflection element can be achieved, which can quickly follow changes in warp thread tension without causing a greater increase in warp thread tension.

A particularly advantageous embodiment of the weaving machine according to the invention is produced by the use of at least one additional or supplementary mass which is connected to the deflection element via a clamping or force-fitting connection only in a force-or frictional engagement. This variant makes simple assembly possible. The screw does not need to be removed but the clamping or force-fitting connection must simply be released.

In principle, additional or supplementary masses of various different forms or shapes are conceivable, such as, for example, rods or elements of flat material, which are mounted on deflection elements distributed over the width of the weaving machine. However, it is most advantageous to use the pipe as an additional or supplementary mass, or also as a deflecting element. Pipes having different diameters and/or different wall thicknesses may be provided. The pipe can be used as a deflecting element, which is supported rotatably or fixedly, or can be connected to the deflecting element via a releasable connection, for example a clamping or force-fitting connection, the deflecting element being embodied, for example, as a bent sheet metal. A plurality of pipes can also be inserted into one another and can thus be combined in a space-saving manner, such as a box of bricks or a building set.

Drawings

Shown as follows:

FIG. 1 is a cross-sectional view of an embodiment of a weaving machine according to the invention, viewed in the weft direction, and

fig. 2 is a diagram of the warp thread tension and the movement of the deflection element during operation of the weaving machine.

Detailed Description

Fig. 1 shows an embodiment of the weaving machine according to the invention in a sectional view, with the viewing direction in the weft direction up to the rear of the machine. Starting from a warp beam, not shown, the warp threads 1 are guided around a deflecting element 2 and from there-via a device for monitoring warp threads 3-are supplied to the front of the weaving machine and to the elements for shed formation and reed beating-up.

In the present example, the deflection element 2 is embodied as a bent metal sheet. It is currently screwed together with a support element 4 in the form of a bent metal plate, which support element 4 is connected at one end with an air bellows 5, while the other end is supported or supported at a hinge point in the frame of the weaving machine 6.

The air bellows 5 here forms a spring element, on which the deflection element 2 is connected to the weaving machine in such a way that the spring force becomes effective on the deflection element 2 when a force is applied or imposed on the deflection element 2 via the warp threads 1.

In this respect, the magnitude of these spring forces depends on the magnitude or level of the air pressure in the air bellows 5. Of course, instead of the air bellows 5, it is also possible to provide purely mechanical spring elements with a correspondingly adapted elasticity or spring rate. Thus, for example, the support element 4 can be embodied as a leaf spring, the bottom end of which is not hinged but is tightly clamped in the frame of the weaving machine 6.

In order to monitor processes on the backrest beam during operation of the weaving machine, it is advisable or appropriate to mount sensors, for example inductive displacement sensors, on the deflection element 2 itself or on the support element 4 or between the spring 5 and the frame 6.

The support element 4 and the deflection element 2 are connected to one another via a threaded connection 7 in such a way that a pipe-shaped additional or supplementary mass 8 can be clamped between the deflection element 2 and the support element 4. Of course, other forms or shapes of the complementary mass 8 are possible-for example, a solid material rod or an element with a rectangular cross-section. By releasing the clamped

connection

2, 4, 7, the supplementary mass 8 can be removed or replaced by a different mass.

During the movement of the deflection element 2, this additional mass 8 moves with it and therefore generates a more or less large additional inertial force during the application or imposition of the acceleration force on the deflection element 2. The inertial force opposes the acceleration of the deflecting element 2. During operation of the weaving machine, this acceleration is generated by the force acting on the deflection element 2 via the warp threads 1. These forces and the movement of the deflecting element 2 therewith are generated in the warp threads by the shed change process and the reed beat-up of the weaving machine.

Fig. 2 shows various time-dependent courses or measured values of the course during the operation of the weaving machine.

The solid line shows the progression or profile of the warp thread tension 10 or warp thread tension 10 (per line cN) over the time span of several weaving cycles. In this respect, sharp peaks 10.1,10.2 mark reed beat-up, respectively. An increase in the warp tension 10 is similarly recognized between each two reed beat-ups, respectively, however, the warp tension 10 is configured to be less jerky. Within these ranges, respectively, shed changes occur, wherein a part of a warp thread 1 changes from top to bottom and a different part of a warp thread 1 moves in the opposite way-the double arrow 11 in fig. 1.

If the deflecting element 2 does not react with a similar rapid compensating movement, the jerky acceleration experienced by the warp 1 during reed beating-up plays a role in a similar jerky rise of the warp tension 10. For comparison, the movement of the deflecting element 12 during pivoting about a pivot point in the frame 6 is shown in the same figure with a dashed line. The illustrated curve or progression 12 corresponds to the displacement of the deflecting element 2 in the area of the thread contact surface of the warp thread 1; in fig. 1, this movement is illustrated by the double arrow 12.

In the present case, it can be seen that the deflecting element 2 is moved substantially synchronously with the rise or increase in the warp thread tension 10 in the context of a shed change process. Thereby, a further increase of the warp thread tension 10 is prevented. This occurs because the deflection element 2 moves approximately + 2 mm from the rest position in the direction towards the air bellows 5 due to the increased warp tension 10.

Shortly before the tension peaks 10.1,10.2, the curve or progression of the warp thread tension 10 has a minimum value, which occurs due to the fact that at this point in time the warp thread 1 runs through the weaving machine without significant deflection upwards or downwards; whereby the warp threads 1 form a closed shed. Thus, a significantly smaller warp thread tension 10 acts on the deflection element 2. This leads to the fact that the deflecting element 2 is deflected towards the rear, counter to the direction of travel of the warp threads 1, due to the spring force of the air bellows 5 — in this respect, it produces a movement of about-2 mm.

It is further seen in fig. 2 that the movement of the deflecting element 12 in the subsequent reed beat-up qualitatively has a different curve or progression than the curve or progression of the warp thread tension 10. Due to the inertial mass, the deflecting element 2 does not activate so quickly as is required to compensate or balance the very rapid rise of the warp thread tension 10 during reed beating-up. The result is a tension peak of warp tension 10.2 shown in figure 2, which is in many cases undesirable, but absolutely necessary in some fabrics with high weft density, in order to even reach the desired weft density.

According to the invention, the inertial forces against the rapid movement of the deflection element 2 can be increased or decreased by replacing, removing or supplementing the additional or supplemental mass 8. In addition to the desired weft density, the rotational speed of the weaving machine, i.e. the time of one weaving cycle, is also taken into account in this respect. At higher rotational speeds-and therefore very short weaving cycles-higher accelerations of the participating elements occur from the beginning due to shed formation and reed beating-up. For large elements, and therefore also for the deflection element 2, these higher accelerations lead to correspondingly higher inertial forces. These higher inertial forces must be applied or imposed via the warp 1. Thus, even with a constant mass relationship, a change or variation in rotational speed has resulted in a change or variation in inertial force. However, at low rotational speeds and high weft densities it may be necessary to increase the inertial forces by mounting or fitting additional masses on the deflecting element 2.

In practice, for example, fabrics with a weft density of 24 picks per cm or insertion are used, the rotational speed of the weaving machine being 600 picks per minute, and an additional mass of the order of 10 kg per metre of fabric width has been used with good success.

With a machine equipped in this way, the additional mass 8 can be removed or replaced according to the invention with such a lower mass if a fabric is to be produced thereafter which does not require high warp tension peaks 10.1, 10.2.

It has been shown that for most cases various additional or supplementary masses 8 are sufficient if a stepwise mass increase or decrease of 2 to 5 times can be achieved. In some special cases, it may also be necessary to have a smaller or larger mass step-thus, for example, 1.5 times this step of mass, or even a multiple between 5 and 8. Thus, an application-dependent adjustment can then be made within a wide range.

Reference numerals

1 warp of yarn

2 deflecting element

3 device for monitoring warp threads

4 support element

5 air bellows

6 loom frame

7 screw connection

8 additional or supplementary masses

10 warp tension or warp tension

10.1,10.2 extreme in the progression of warp tension

11 movement of warp threads during shed change

12 movement of the deflecting element

Claims

1. A method for changing the dynamic behavior of a backrest beam of a weaving machine, wherein the backrest beam comprises at least one deflection element (2) for deflecting warp threads (1), wherein the deflection element (2) is connected to the weaving machine via one or more spring elements in such a way, i.e. such that when a force is exerted on the deflecting element (2) via the warp thread (1), inertial and spring forces become effective on the deflecting element (2), characterized in that the effective inertial mass on the deflecting element (2) is thereby varied in order to adapt the dynamic behavior of the backrest beam to changing weaving conditions or requirements, replacement, removal or supplementation of parts of the deflection element (2) or parts connected to the deflection element (2), the inertial mass effective for the deflecting element (2) is increased or decreased by a factor of between 1.5 and 8.

2. Method according to claim 1, characterized in that the inertial mass effective on the deflecting element (2) is increased by replacing or supplementing parts when the weaving machine is switched from a fabric with a lower weft density to a fabric with a higher weft density.

3. Method according to claim 1, characterized in that the inertial mass effective on the deflecting element (2) is reduced by replacing or removing parts when the weaving machine is converted from a fabric with a higher weft density to a fabric with a lower weft density.

4. Method according to any one of the preceding claims, characterized in that the inertial mass effective for the deflecting element (2) is increased or decreased by a factor comprised between 2 and 5.

5. Weaving machine with a backrest beam comprising at least one deflection element (2) for deflecting warp threads (1), wherein the deflection element (2) is connected with the weaving machine via one or more spring elements in such a way that upon application of force and motion via the warp threads (1) inertial and spring forces become effective on the deflection element (2), characterized in that the inertial mass effective on the deflection element (2) is variable in order to adapt the dynamic behavior of the backrest beam to changing weaving conditions or requirements, the parts of the deflection element (2) or the parts connected with the deflection element (2) being replaced, removed or supplemented, the inertial mass effective on the deflection element (2) being increased or decreased by a factor of between 1.5 and 8.

6. Weaving machine according to claim 5, characterized in that the inertial mass effective on the deflecting element (2) can be increased or decreased by a factor between 2 and 5.

7. Weaving machine according to claim 5 or claim 6, characterized in that the deflection element (2) is embodied as a bent metal plate or as a tube.

8. Weaving machine according to claim 5 or claim 6, characterized in that for changing the inertial mass effective on the deflection element (2) there is at least one additional mass (8), which at least one additional mass (8) is connected with the deflection element (2) via a releasable clamping connection (4, 7).

9. Weaving machine according to claim 8, characterized in that the additional mass (8) is embodied as a tube.