WO2018041592A1 - Method and device for changing the dynamic behaviour of a back rest of a weaving machine - Google Patents

Abstract

The invention relates to a method for changing the dynamic behaviour of a back rest of a weaving machine, and to a weaving machine having a back rest, wherein the back rest contains at least one deflecting element (2) for deflecting warp threads (1), wherein the deflecting element (2) is connected to the weaving machine via one or more spring elements in such a way that, when forces are applied to the deflecting element (2) via the warp threads (1), inertia forces and spring forces become active on the deflecting element (2). The inert mass acting on the deflecting element (2) is changed in order to adapt the dynamic behaviour of the back rest to altered weaving conditions in that parts of the deflecting element (2) or parts which are connected to the deflecting element (2) are replaced, removed or supplemented.

Description

 Method and device for changing the dynamic behavior of a spreading bar of a weaving machine

Technical area

 The present invention relates to a method for changing the dynamic behavior of a spreading bar of a weaving machine and to a weaving machine with a bar, which is adapted to the execution of such a method.

State of the art

 In weaving machines, devices for deflecting warp threads are known in the state of the art, which are referred to as a bar or a bowing tree. Such a device is shown for example in DE 10 2006 061 376 A1. This relates to a bowing for a weaving machine, are compensated in the warp thread movements in the warp direction by an oscillating arranged on a mass-optimized leaf spring Fadenumlenkelement. The aforementioned mass optimization aims in the prior art to make the dynamic behavior of the coating tree at high weaving speeds so that the lowest possible warp tensile forces occur. This is achieved by a low inertial mass of Fadenumlenkelements and a low inertial mass of the leaf spring.

WO 2012031802 A2 describes a coating tree for guiding warp threads with a deflection element, which is supported on the loom via an elastic element. Again, the task is described to provide the lowest possible inertial masses on Fadenumlenkelement to keep the warp thread load low.

DE 1 138 715 A discloses a coating bar which is rotatably mounted in clamping levers which are pivotable about a fixed axis on the machine frame and under the action of a force accumulator for pressing the clamping bar to the Warp threads are. In this case, at least one of the screed bearings located in the clamping levers has a braking device for simultaneously damping the vibrations in the self-rotation and in the swiveling movement of the screed bar. In this way, the dynamic behavior of the

Streichbalkens regulated by changing leverage.

The use of such stringers has now become

It has been emphasized that the lowest possible warp load is not sensible for all weaving conditions and not for all fabrics. Especially in the case of technical fabrics with a high weft density, ie with a high number of weft threads in a given fabric length, it can be seen that higher warp tension forces or warp thread tensions are favorable at least in a specific phase of the weaving process. This is the phase in which a weft thread after its entry into the

Shed by a reed to the edge or the binding point of the already existing tissue is struck. If a high weft density, ie a high number of weft threads in a given fabric length is to be achieved, a higher warp tension or warp tension is at least cheaper at sheet stop, because then the binding point evades less when a new weft thread is struck by the reed to the binding point. This ensures that successive weft threads in the tissue are very close together.

On the other hand, the warp tension in the other phases of the weaving process should not be unnecessarily high, as explained in detail in the prior art. This is especially true for the phase of the change of subject, which is between two

Leaf stops done. Depending on the pattern of the fabric is doing a change of all or more warp threads from the upper compartment in the lower compartment and vice versa. In this case change the warp threads are geometrically deflected from their straight course by the weaving machine. This deflection is accomplished by shifting the warp threads vertically up or down by healds. The warp threads in the strands are subjected to friction. It is advantageous to avoid thread breakages, if there are the lowest possible warp tension in this subject change. It thus turns out that it would be advantageous to produce higher warp thread tensions for certain fabrics, at least during the sheet stop, for a short time, while it makes sense for other fabrics to work with low warp yarn tensions even in the case of sheet folding.

Thus, there arises the task of being able to work with different types of warp thread adapted to the type of fabric, at least in the case of the sheet stop of a weaving machine, for different types of fabric. Description of the invention

The object is achieved by a method and a loom according to the independent claims. The method for changing the dynamic behavior of a carding bar of a weaving machine relates to a bar with at least one

Deflection element for deflecting warp threads. The deflecting element may for example consist of a continuous bent sheet, the

Longitudinal axis transverse to the direction of the warp threads. The warp threads are usually performed starting from the warp beam on the deflection of the spreading bar to the elements of the shedding of the loom.

Of course, instead of a single deflecting element, several deflecting elements distributed over the width of the weaving machine are possible - for example a plurality of sheet metal elements adapted to the fabric width.

The deflecting element is connected via one or more spring elements with a

Machine frame of the loom connected in such a way that when applying forces that cause acceleration or movement of the deflecting element relative to the machine frame, inertial forces and spring forces on the deflecting effect. Acceleration forces are exerted by the warp threads on the deflection during operation of the loom. The inertial forces are primarily the forces that occur as a result of the acceleration of the inertial mass of the deflecting element. To this inertial mass may also include other components which are attached to the deflecting element or connected thereto in such a way that they are in one movement or

Be moved deflection of the deflecting.

The spring forces caused by a deflection of the deflecting element with the associated spring element from a rest position in a deflected position. Such a deflection from the rest position into a deflected position usually already takes place through the warp threads, which are guided under tension over the deflection element. As spring elements, for example, leaf springs are used, which are supported at one end on the machine frame of the loom and carry the deflecting at its other end. It is also conceivable, however, an arrangement in which the deflecting movable on

Machine frame supports, for example, in a joint, with an additional one

Spring element between deflecting element and machine frame is arranged such that at a deflection of the deflecting element one end of the spring is deflected. As springs, leaf springs, torsion spring, coil springs or air springs come into question.

The invention is characterized in that the effective at an acceleration of the deflecting inertial mass is changed in order to adapt the dynamic behavior of the spreading bar to changing weaving conditions. This is done in such a way that parts of the deflecting element or other components which are connected to the deflecting, exchanged, removed or supplemented.

By changing the inertial mass of the deflecting element, the dynamic behavior of the stripe bar becomes short jerky

Acceleration processes - for example, the sheet stop - more affected than slow, more sinusoidal acceleration processes - for example, the subject change. This is particularly important in order to achieve a higher resistance of the deflecting element to achieve higher warp tension in the sheet stop without unnecessarily increasing the warp tension in the area of the change of subject; that is, without higher stress on the warp threads when changing subjects.

For fabrics with less high weft density can then be reversed by

Reducing the effective inertial mass, the warp load over the entire area of the weaving cycle (sheet stop and tray replacement) are kept low, because the lighter deflector less resistance to the acceleration processes.

In a first method embodiment, it is therefore provided that, by exchanging or supplementing parts, the inert mass acting on the deflecting element is increased when the loom is switched from a fabric having a lower weft density to a fabric having a higher weft density.

The increased inertial mass causes a greater resistance of the

Deflection element against jerky movements. The result of this is that the jerky sheet stop of the weaving machine now causes temporarily higher warp tension in the warp threads. These temporarily higher warp stresses in the sheet stop are a prerequisite for the production of a fabric with higher weft density.

In a second method embodiment, it is provided that, by exchanging or removing parts, the inert mass acting on the deflecting element is reduced when the weaving machine is driven by a fabric with a higher

 Shot density is switched to a tissue with lower weft density.

 The reduced inertial mass causes a lower resistance of the

 Deflection element against jerky movements. This leads to the fact that

Blattanschlag the loom now in the warp threads in comparison to previously lower warp tension and thus lower stresses of

Warp threads occur. Differences in the dynamic behavior of the stripe bar arise even with slight differences in the effective effective at the deflecting inertial mass. However, it is advantageous if the effective inertial mass is increased or decreased by a factor which is between 1, 5 and 8, preferably by factors between 2 and 5 - for example 2.5 or 3 or 4. With an assortment of different additional masses in a corresponding gradation is the dynamic behavior to a variety of requirements such as weft densities or

Customizable speeds. Another aspect of the invention relates to a loom with a

 Brushing bar with at least one deflecting element for deflecting warp threads. The deflecting element is connected via one or more spring elements with the

Weaving machine is connected in such a way that when applying forces and movements on the warp threads inertial forces and spring forces on the

Deflecting effective. Such acceleration forces are exerted by the warp threads on the deflection during operation of the weaving machine.

The inertial forces are primarily the forces that occur as a result of the acceleration of the inertial mass of the deflecting element. To this inertial mass may also include other components that are attached to the deflection.

The spring forces caused by a deflection of the deflecting element with the associated spring element from a rest position in a deflected position. Such a deflection from the rest position into a deflected position usually already takes place through the warp threads, which are guided under tension over the deflection element. As spring elements, for example, leaf springs are used, which are supported at one end on the machine frame of the loom and carry the deflecting at its other end. It is also conceivable, however, an arrangement in which the deflecting movable on

Machine frame supported, for example, in a joint, wherein additionally a spring element between deflecting element and machine frame is arranged such that at a deflection of the deflecting element and the one end of the spring is deflected. As springs leaf springs, torsion springs, coil springs or air springs come into question.

The weaving machine according to the invention is characterized in that the effective on the deflecting inertial mass is variable to the dynamic

Adjusts the behavior of the bow to suit changing web conditions. This variability is given by the fact that parts of the deflecting element or parts which are connected to the deflecting element are designed to be interchangeable, removable or replaceable.

To be particularly advantageous has been found when an assortment of different deflecting elements or additional masses is kept ready, with which the effective on the deflecting inertial mass by a factor of 1, 5 - 8 can be increased or reduced, preferably by factors between 2 and 5 - Example 2.5 or 3 or 4.

As a starting point for a weaving machine according to the present invention, an embodiment has proven in which the deflecting element is designed as a bent sheet metal. As has already been shown in the prior art, with such a sheet, a very low-mass deflection element can be realized, which can quickly follow changes in the warp tension without causing larger increases in the warp tension.

A particularly advantageous embodiment of the weaving machine according to the invention results from the use of at least one additional mass, which is connected to the deflecting element only frictionally via a clamping connection. This variant allows easier installation. There are no screws removed, but only a clamp to be solved. In principle, various forms of additional masses are conceivable, for example rods or elements made of flat material, which are distributed over the width of the weaving machine attached to the deflecting element. The cheapest, however, is the use of tubes as additional mass or pipes as deflection. It can pipes with different diameters and / or different Wall thicknesses are provided. Tubes can be - rotatably or fixedly mounted - use as a deflecting element or via a detachable connection - for example, a clamp - with a deflecting element, which is designed for example as a bent sheet metal. Several pipes can also be inserted into each other and thus combined to save space in the manner of a modular system.

Brief description of the drawings In the drawings:

Figure 1 is a sectional view of an embodiment of the invention

 Weaving machine with a view in the weft direction, and Figure 2 is a diagram of the warp tension and the movement of the

 Deflection element during operation of a loom.

Figure 1 shows an embodiment of the weaving machine according to the invention in a sectional view looking in the weft direction on the rear part of the

Machine. Starting from a warp beam, not shown, warp threads 1 are guided around a deflection element 2 and from there - via a device for monitoring the warp threads 3 - fed to the front part of the weaving machine and the elements for the shedding and the sheet stop. The deflecting element 2 is designed in the present example as a bent sheet metal. It is presently screwed to a support member 4 in the form of a bent plate, which is at one end with an air bladder 5 in conjunction, while the other end at a hinge point in the machine frame of

Weaving machine 6 is supported.

The air bellows 5 here forms a spring element, via which the deflecting element 2 is connected to the loom such that when applying forces on the warp threads 1 on the deflection element 2 spring forces on the deflection element. 2 be effective.

The size of these spring forces depends on the height of the air pressure in the air bellows 5. Of course, purely mechanical spring elements with appropriately adapted elasticity or spring stiffness could be provided instead of the pneumatic bellows 5. Thus, for example, the support member 4 may be formed as a leaf spring whose lower end in the frame of the loom 6 is not articulated, but firmly clamped. In order to be able to monitor the operations on the coating bar during operation of the weaving machine, it makes sense to attach a sensor, for example an inductive displacement sensor, to the deflection element 2 itself or to the support element 4 or between the spring 5 and the machine frame 6. The support element 4 and the deflecting element 2 are connected to one another via a screw connection 7 such that between the deflecting element 2 and the supporting element 4 a tubular additional mass 8 can be clamped. Of course, other forms of additional mass 8 are possible - e.g. Bars made of solid material or elements with rectangular cross-section. By loosening the clamp 2, 4, 7, the additional mass 8 can be removed or replaced by another.

This additional mass 8 is moved during movements of the deflecting element 2 and therefore causes the action of acceleration forces on the

Deflection element 2 more or less large additional inertial forces. The

Inertia forces counteract the acceleration of the deflecting element 2.

 Such accelerations are generated during operation of the loom by forces acting on the warp 1 on the deflecting element 2. These forces and the consequent movements of the deflecting element 2 are caused in the warp threads 1 by the tray changing operations and the sheet stop of the loom.

FIG. 2 shows various time-dependent courses of measured values during operation of a weaving machine. The solid line shows the course of the warp tension 10 and the warp tension 10 (cN per thread) over a period of several

Weaving cycles. The sharp tips 10.1, 10.2 mark one each

Reed. Between each two blade stops can also be seen increases in the warp tension 10, which are formed less jerky. In these areas, a change of subject takes place, in which a part of the warp threads 1 changes from top to bottom, while another part of the warp threads 1 is moved in opposite directions - double arrow 1 1 in Figure 1. The jerky acceleration that the warp threads 1 experience in the sheet stopper is reflected in a jerky increase in the warp tension 10 when the deflecting element 2 does not react with a similarly rapid compensating movement. For comparison, as a dashed line in the same diagram, the movement of the deflecting element 12 when pivoting about the pivot point in

Machine frame 6 shown. The recorded course 12 corresponds to the path of the deflecting element 2 in the region of the thread support of the warp threads 1; in Figure 1, this movement is shown by a double arrow 12.

In the present case, it can be seen that the deflecting element 2 in the region of

Tray changes in about synchronously with the increase of the warp tension 10 is moved. A further increase in the warp tension 10 is thus prevented. This is done by the deflecting element 2 is moved as a result of the rising warp tension 10, starting from a rest position by about + 2 mm in the direction of the air bladder 5.

Shortly before the voltage peaks 10.1, 10.2, the course of the warp tension 10 has minimal values which result from the warp threads 1 passing through the weaving machine at this point of time without appreciable deflection upwards and downwards; the warp threads 1 form a closed compartment. Therefore, at this moment significantly lower warp tension forces 10 act on the deflecting element 2. As a result, as a result of the spring forces of the pneumatic bellows 5, the deflecting element 2 is deflected backwards, counter to the running direction of the warp threads 1 - it makes a movement of approx. - 2 mm. It can be seen in Figure 2 further that the now following sheet stop the

Movement of the deflecting element 12 qualitatively has a different course than the course of the warp tension 10. Due to the inertial mass is the

Deflection element 2 is not set in motion as quickly as would be required to compensate for the very rapid increase of the warp tension 10 at the sheet stop. The result is the tension peak of the warp tension 10.2 shown in FIG. 2, which is undesirable in many cases, but which is absolutely necessary for some fabrics with high weft density in order to achieve the desired

To achieve shot density at all.

The inertial forces, which are opposed to a rapid movement of the deflecting element 2, can be increased or reduced according to the invention by exchanging, removing or supplementing additional masses 8. In addition to the desired shot density while the speed of the loom, i. to consider the time for a weaving cycle. At higher speeds - so very short

 Web cycles - resulting from the shedding and the sheet stop from the outset higher accelerations of the elements involved. These higher

Accelerations lead in mass-afflicted elements - including the deflection element 2 - to correspondingly higher inertial forces. These higher inertial forces must be applied over the warp threads 1. A

 Changing the speed leads thus even with unchanged mass ratios to a change in the inertial forces. At low speed and high shot density, however, it may be necessary to increase the inertial forces by adding additional masses on the deflection element 2.

In practice, for example, in a woven fabric having a weft density of

24 S / cm at a speed of the loom of 600 S / min an additional mass in the order of 10 kg per meter fabric width has been used with good success.

If a fabric is then to be produced with a machine equipped in this manner in which high warp tension peaks 10.1, 10.2 are not desired, according to the invention additional masses 8 can be removed or exchanged for those of lesser mass. It has been shown that an assortment of additional masses 8 is sufficient for most cases, if thus gradually mass increases or

Reductions by factors of 2 to 5 are achievable. In a few special cases, even smaller or even larger gradations of the masses may be necessary - for example, those by a factor of 1, 5 or even by factors between 5 and 8. Thus, depending on the application, adjustments in a wide range are possible.

reference numeral

warp

 deflecting

 Device for monitoring the warp threads

support element

 bellows

 Machine frame of the weaving machine

 screw

 additional mass

 Warp tension or warp tension Extreme values in the course of warp tension

Movement of the warp threads when changing subjects

Movement of the deflecting element

Claims

P a n t a n s p r e c h e Method for changing the dynamic behavior of a Streamer of a weaving machine, wherein the coating bar at least one deflecting element (2) for deflecting warp threads (1), wherein the deflecting element (2) via one or more spring elements with the Weaving machine is connected in such a way that upon application of forces on the warp threads (1) on the deflecting element (2) inertia forces and spring forces on the deflecting element (2) are effective, characterized in that the case of the deflecting element (2) effective inertial mass changed In order to adapt the dynamic behavior of the brush to changing weaving conditions, parts of the deflecting element (2) or parts connected to the deflecting element (2), exchanged, removed or supplemented. A method according to claim 1, characterized in that by exchanging or supplementing parts, the inert mass acting on the deflecting element (2) is increased when the loom is moving from a lower weft density fabric to a higher fabric Shot density is changed. A method according to claim 1, characterized in that by an exchange or a removal of parts on the deflecting element (2) effective inertial mass is reduced when the weaving machine from a higher weft density fabric to a lower fabric Shot density is changed. Method according to one of the preceding claims, characterized in that the effective mass acting on the deflection element (2) is increased or reduced by a factor which lies between 1, 5 and 8, preferably by a factor between 2 and 5. Weaving machine with a coating bar, which contains at least one deflecting element (2) for deflecting warp threads (1), wherein the deflecting element (2) is connected to the weaving machine via one or more spring elements in such a way that when applying forces and movements over the warp threads ( 1) inertia forces and spring forces on the deflecting element (2) become effective, characterized in that on the deflecting element (2) effective inertial mass is variable to adapt the dynamic behavior of the spreading bar to changing weaving conditions by parts of the deflecting element (2) or Parts that are connected to the deflecting element (2), exchanged, removed or supplemented. Weaving machine according to claim 5, characterized in that on the deflecting element (2) effective inertial mass by a factor of 1, 5 - 8 can be increased or reduced, preferably by a factor of 2 -. 5 Weaving machine according to claim 5 or 6, characterized in that the deflecting element (2) is designed as a bent sheet metal or as a tube. Weaving machine according to claim 5 or 6, characterized in that for changing the deflecting element (2) effective inertial mass at least one additional mass (8) is present, which with the  Deflection element (2) via a releasable clamping connection (4, 7) is connected. 9. loom according to claim 8, characterized in that the  Additional mass (8) is designed as a tube.