EP2537967B1 - Method for operating a non-woven fabric layer - Google Patents

Abstract

Operating cross lapper (2) for placing a fleece made of a gauze web (6), comprises (a) providing a cross-lapper comprising an upper carriage (30), a laying carriage (10), through which the gauze web coming from the upper carriage is guided and serves for delivering the gauze web on a output conveyor belt, and at least two gauze conveyor belts (16) for guiding the gauze web in the cross lapper towards the laying carriage, and (b) providing a device that is upstream to the cross lapper or is integrated in the inlet region, for temporarily altering speed of the gauze web. Operating cross lapper (2) for placing a fleece made of a gauze web (6), comprises (a) providing a cross-lapper comprising an upper carriage (30) that is movable in transverse direction, through which the gauze web produced by a web producer is guided, a laying carriage (10) that is movable in the transverse direction, through which the gauze web coming from the upper carriage is guided, and the gauze web is delivered on a output conveyor belt, and at least two gauze conveyor belts (16) for guiding the gauze web in the cross lapper towards the laying carriage, and (b) providing a device that is upstream to the cross lapper or is integrated in the inlet region, for temporarily altering speed of the gauze web, where the gauze web is guided to the cross lapper with variable gauze entering speed. The upper carriage and the laying carriage are moved back and forth in a laying cycle substantially in the same direction by round trip. The laying carriage is moved back and forth in each laying cycle between two clearly defined reversal points. The average of the amount of the laying carriage speed on the outward journey of the laying carriage in each laying cycle or at least in some laying cycles is different to the average of the amount of the laying carriage speed on the return journey of the laying carriage, and the average of the amount of the laying carriage speed in each laying cycle or at least in some laying cycles during the outward journey of the laying carriage is different to double the average of the amount of the upper carriage speed during the outward journey of the laying carriage.

Description

The present invention relates to a method for operating a nonwoven layer for laying a nonwoven fabric from a card web.

Nonwovens serve to deposit the card web produced by a carding machine as evenly as possible on a delivery conveyor belt in multilayered layers to form a nonwoven. The card web is usually first passed through a superstructure and from there to a laying carriage, through the Ablegespalt the card web is placed on the delivery conveyor belt. At least two pile conveyor belts serve to guide the card web through the nonwoven layer. The movements of the pile conveyor belts, the superstructure, the laying carriage and, where appropriate, the delivery conveyor belt are controlled in a coordinated manner.

Fleece layerers are often preceded by means for changing the pile speed, which are used primarily to control the pile web of the pile web in order to be able to produce a profiling of the laid nonwoven fabric or to perform an edge thickness compensation of the laid nonwoven web. Such means for changing the Florlaufgeschwindigkeit include, for example, different speed driven driven rollers on the carding machine upstream carding, as for example WO 99/24650 A1 is known, or the provision of a separate drafting between carding and nonwoven, see for example EP 1 532 302 B1 ,

In both patent documents mentioned above, the fluctuating pile in speeds in the nonwoven layer are compensated by an integrated buffer, which is achieved by an increased travel of the upper carriage and the longer loop of the first pile conveyor belt achieved thereby. As a result, the nonwoven is due to the longer travel of the superstructure rear longer, which is often undesirable and beyond the existing parking space.

The present invention has for its object to provide a nonwoven, which provides a compensation for fluctuating Floreinlaufgeschwindigkeiten in a simple manner and at the same time keeps the rear space requirement of the webbing low.

This object is solved by the features of claim 1.

• Bereitstellen eines Vlieslegers mit einem in Querrichtung verfahrbaren Oberwagen, durch den eine von einem Florerzeuger erzeugte Florbahn geführt wird, einem in Querrichtung verfahrbaren Legewagen, durch den die vom Oberwagen kommende Florbahn geführt wird und der zur Abgabe der Florbahn auf ein Abliefertransportband dient, und mindestens zwei Flortransportbändern zur Führung der Florbahn im Vliesleger hin zum Legewagen;
• Bereitstellen einer Vorrichtung, die dem Vliesleger vorgeschaltet oder in dessen Einlaufbereich integriert ist, zur zeitweiligen Veränderung einer Geschwindigkeit der Florbahn, wodurch die Florbahn dem Vliesleger mit variabler Floreinlaufgeschwindigkeit zugeführt wird;
• wobei der Oberwagen und der Legewagen in einem Legezyklus im Wesentlichen gleichsinnig mittels Hinfahrt und Rückfahrt hin- und herbewegt werden, wobei der Legewagen in jedem Legezyklus zwischen zwei fest definierten Umkehrpunkten hin- und hergefahren wird.

According to the invention, the method for operating a nonwoven layer for laying a nonwoven fabric from a card web comprises the following steps:

• Provision of a nonwoven layering machine with a transversely movable upper carriage, through which a web produced by a pile fabricator, a transversely movable carriage, through which the upper carriage coming from the flagship is guided and which serves to deliver the card web on a delivery conveyor belt, and at least two Pile conveyor belts for guiding the card web in the web laying machine to the laying carriage;
• Providing a device upstream of or integrated with the leveler for temporarily altering a speed of the card web, whereby the card web is fed to the variable file entry speed leveler;
• wherein the superstructure and the laying carriage are reciprocated in a laying cycle substantially in the same direction by means of outward and return travel, wherein the laying carriage is reciprocated in each laying cycle between two fixed reversal points.

The average of the amount of speed of the laying carriage on its outward journey in each laying cycle or at least in some laying cycles is different from the average of the speed amount of the laying carriage on its return journey, and the average of the speed amount of the laying carriage in each laying cycle or at least in some laying cycles during the outward journey of the laying carriage is different to twice the average of the amount of speed of the superstructure during the outward journey of the carriage.

Thus, it is possible to compensate for the variable Floreinlaufgeschwindigkeiten in a simple manner and thereby limit the rear space requirement of the fleece layer due to the limited travel of the superstructure.

Preferably, the average of the speed amount of the laying carriage on its outward journey in each laying cycle or at least in some laying cycles is greater than twice the average speed of the superstructure during the outward journey of the laying carriage, and the average of the speed amount of the laying carriage on its outward journey is in each lay cycle at least in some laying cycles, greater than the average of the speed of the carriage on its return journey. As a result, the laying carriage picks up the superstructure on the outward journey faster, which means the belt loop is emptied around the uppercarriage. The superstructure can therefore be limited to a certain path length despite partially higher pile entrance speed on the outward journey. At the same time, the higher pile infeed speed is compensated by the asynchronously higher laying carriage speed on the outward journey.

In terms of mass flow consistency, it is advantageous if the average of the speed amount of the laying carriage after several laying cycles corresponds to the average of the speed amount of the variable pile infeed speed.

It is particularly preferred if the average of the speed amount of the laying carriage after each laying cycle corresponds to the average of the speed amount of the variable pile running speed. Then the mass flow constancy can be produced in each laying cycle and the compensation in subsequent laying cycles can be made more variable.

In order to limit the tail-end footprint of the fleece layer even more precisely and to reduce it to a minimum, it is advantageous if two defined reversal points are spatially defined for the superstructure and a speed profile of the laying carriage is set such that the superstructure does not overflow independently of the variable pile infeed speed the predetermined turning points goes out.

Fig. 1

ist eine schematische Querschnittsansicht einer Ausführungsform eines Vlieslegers, in dem die Erfindung angewendet werden kann;

Fig. 2

ist eine graphische Darstellung eines Beispiels der Geschwindigkeitsprofile des Floreinlaufbandes, des Oberwagens und des Legewagens des Vlieslegers aus Fig. 1 bei konstanter Floreinlaufgeschwindigkeit;

Fig. 3a

ist eine graphische Darstellung einer Möglichkeit der Geschwindigkeitsprofile des Floreinlaufbandes, des Oberwagens und des Legewagens des Vlieslegers aus Fig. 1 bei variabler Floreinlaufgeschwindigkeit und erfindungsgemäßer Pufferbildung;

Fig. 3b

ist eine graphische Darstellung des vom Oberwagen bei der Geschwindigkeitsverteilung gemäß Fig. 3a zurückgelegten Weges;

Fig. 4a

ist eine graphische Darstellung einer weiteren Möglichkeit der Geschwindigkeitsprofile des Floreinlaufbandes, des Oberwagens und des Legewagens des Vlieslegers aus Fig. 1 bei variabler Floreinlaufgeschwindigkeit und erfindungsgemäßer Pufferbildung;

Fig. 4b

ist eine graphische Darstellung des vom Oberwagen bei der Geschwindigkeitsverteilung gemäß Fig. 4a zurückgelegten Weges;

Fig. 5a

ist eine graphische Darstellung einer weiteren Möglichkeit der Geschwindigkeitsprofile des Floreinlaufbandes, des Oberwagens und des Legewagens des Vlieslegers aus Fig. 1 bei variabler Floreinlaufgeschwindigkeit und erfindungsgemäßer Pufferbildung;

Fig. 5b

ist eine graphische Darstellung des vom Oberwagen bei der Geschwindigkeitsverteilung gemäß Fig. 5a zurückgelegten Weges;

Fig. 6

ist eine schematische Querschnittsansicht einer weiteren Ausführungsform eines Vlieslegers, in dem die Erfindung angewendet werden kann.

Further features and advantages of the present invention will become apparent from the following description with reference to the drawings.

Fig. 1

Fig. 3 is a schematic cross-sectional view of one embodiment of a nonwoven layer to which the invention can be applied;

Fig. 2

Figure 4 is a graphical representation of one example of the speed profiles of the infeed conveyor belt, hauler, and laying carriage of the web laying machine Fig. 1 at constant pile infeed speed;

Fig. 3a

Fig. 3 is a graphical representation of one way of speeding profiles of the infeed belt, hauler, and laying carriage of the batt Fig. 1 at variable pile infeed speed and buffering according to the invention;

Fig. 3b

is a graphic representation of that of the superstructure in the velocity distribution according to Fig. 3a traveled way;

Fig. 4a

is a graphical representation of another way the speed profiles of the pile infeed belt, the superstructure and the laying carriage of the nonwoven layer from Fig. 1 at variable pile infeed speed and buffering according to the invention;

Fig. 4b

is a graphic representation of that of the superstructure in the velocity distribution according to Fig. 4a traveled way;

Fig. 5a

is a graphical representation of another way the speed profiles of the pile infeed belt, the superstructure and the laying carriage of the nonwoven layer from Fig. 1 at variable pile infeed speed and buffering according to the invention;

Fig. 5b

is a graphic representation of that of the superstructure in the velocity distribution according to Fig. 5a traveled way;

Fig. 6

Fig. 3 is a schematic cross-sectional view of another embodiment of a nonwoven layer in which the invention can be applied.

Fig. 1 shows a schematic cross-sectional view of a nonwoven layer 2, to which the present invention can be applied. One recognizes in Fig. 1 the nonwoven layer 2 with an endless circulating delivery conveyor belt 4, which is intended to carry away a laid out of a card web 6 fleece in a direction perpendicular to the drawing plane transport direction. From guide devices of the delivery conveyor belt 4, an upper guide roller 8 is shown.

About the delivery conveyor belt 4 is a laying carriage 10 on rails (not shown) moved back and forth. In the laying carriage 10, two guide rollers 12 and 14 are freely rotatably mounted. The first guide roller 12 is partially wrapped by a pile conveyor belt 16, hereinafter also called second pile conveyor belt 16. The second pile conveyor belt 16 is fixed at its first end 18 in the machine frame, not shown, of the nonwoven layer 2 attached and runs from there at a close distance above the delivery conveyor belt 4 to laying carriage 10, where it is deflected by 180 ° and then returned via four stationary guide rollers 20, 22, 24, 26 to the second guide roller 14 in the laying carriage. The deflection roller 14, which is also rotatably mounted in the laying carriage 10, is partially wrapped by the second pile conveyor belt 16, so that the pile conveyor belt 16 is deflected by 180 ° and from the lower exit region of the laying carriage 10 at a close distance above the delivery conveyor belt 4 runs until it its second end 28 is in turn firmly connected to the machine frame of the webbed 2.

At the carriage 10, a chain or a toothed belt is mounted, which runs for example via a drive gear connected to a motor and a deflection wheel (all elements not shown). With the aid of these drive devices, the laying carriage 10 can be moved back and forth across the delivery conveyor belt 4 transversely to its transport direction.

In about the same height as the laying carriage 10 is in the machine frame of the webbing 2 an upper carriage 30 transversely to the transport direction of the delivery conveyor belt 4 on rails (not shown) movably mounted. The rails may be the same rails on which the laying carriage 10 is movably mounted. The uppercarriage 30 has an upper deflecting roller 32 and a lower deflecting roller 34, which are laterally offset from one another. About these two guide rollers 32, 34 runs another Flortransportband 36, which is subsequently called first Flortransportband 36. In the area bounded by the two deflection rollers 32, 34 in the uppercarriage 30, the first pile conveyor belt 36 slopes inclined downwards.

Starting from the lower deflecting roller 34 in the uppercarriage 30, the first Flortransportband 36 runs parallel to the right upper strand of the second Flortransportbandes 16. The first Flortransportband 36 runs straight through the laying carriage 10 and is after the laying carriage 10 via a stationary mounted, motor-driven guide rollers 38 and from there via a guide roller 42 mounted in a tensioning carriage 40, in order to then run over a plurality of guide rollers 44, 46, 48, 50 fixedly mounted in the machine frame of the webbing 2 before it reaches the superstructure 30 again. The superstructure 30 and the tensioning carriage 40 may be connected to each other via a chain or a toothed belt (not shown), which via a with a motor (not shown) connected to the drive gear and a deflection wheel, which are mounted in the machine frame runs (not shown). The clamping carriage 40 is also on rails (not shown) movably mounted. It may also be advantageous if the movements of superstructure 30 and clamping carriage 40 are decoupled from each other.

In the area between the lower deflecting roller 34 of the upper carriage 30 and the second deflecting roller 14 of the laying carriage 10, portions of the first pile transport belt 36 and of the second pile transport belt 16 are guided parallel to one another in close proximity, so that a card web 6 guided from the first web transport belt 36 in said Area between the superstructure 30 and the laying carriage 10 of the first pile conveyor belt 36 and the second pile conveyor belt 16 is sandwiched. In this case, the card web 6 is supported by the second web transport belt 16. In addition, the two take over between carriage 10 and machine frame of the webbing 2 extending portions of the second Flortransportbandes 16 at the same time take over the function of a cover strip for the laid nonwoven.

One recognizes in Fig. 1 in that, during operation, the superstructure 30 and its associated tensioning carriage 40 execute a mutually opposite movement. The tensioning carriage 40 serves to keep the loop length of the first pile conveyor belt 36 constant.

The movements of laying carriage 10 and superstructure 30 are usually matched to one another such that upon feeding the card web 6 at uniform speed into the fleece layer 2 a controlled placement of the card web 6 without stretching or compression within the fleece layer 2 on the delivery conveyor 4 can take place. In this case, the superstructure 30 moves in each case substantially in the same direction with the laying carriage 10, ie in the same direction, on average only half as fast as the laying carriage 10. It is also taken into account the fact that the laying carriage 10 in the region of its movement reversal position to Standstill must be slowed down and accelerated again. In the area of the reversal points, the superstructure 30 will usually not travel in the same direction as the laying carriage 10 in the short term; However, this should be encompassed by the term "substantially in the same direction". Nonwoven layers 2, in which superstructure 30 and laying carriage 10 move substantially in the same direction, are also referred to as "synchronous runner".

Between the two guide rollers 12 and 14 in the laying carriage 10, a gap is formed, which is referred to as a discharge gap. In operation of the fleece layer 2 both pile conveyor belts 16, 36 driven so that they run in the sandwich area with the same relative speed to transport the card web 6 between them without delay.

According to the invention, the card web 6 is then fed to the leveler 2 at a variable speed in the direction of web flow A because a device 52 for changing the web speed is arranged in front of the web 2 or in the inlet area of the web 2 (see Fig. 6 ). The device 52 may be a cyclically operating drafting system as shown in FIG Fig. 6 is shown, which generates with clamping roller pairs an alternating thickness in the card web 6 for the purpose of achieving a transverse profiling of the laid web. Such a drafting system is, for example, in EP 1 381 721 B1 whose content is to be included here in full by reference. Likewise, other known devices 52 for changing the Florlaufgeschwindigkeit can be used, for example, driven with variable speed pickup rollers of the carding according to WO 99/24650 A1 ,

Fig. 2 . 3a . 4a and 5a show diagrams with velocity profiles in a nonwoven layer. where V is the pile infeed speed in the lapper 2, W is the carriage carriage speed, and U is the carriage speed. In all these diagrams, the speed (in meters per minute) is plotted over time (in seconds). In this case, the time zero defines in each case the front reversal point U _{0 of} the laying carriage 10, ie in Fig. 1 and 6 In all figures, exactly one laying cycle is shown, during which the laying carriage 10 first from the front reversal point U ₀ on the delivery conveyor belt 4 in the direction of the rear-side reversal point U ₁ (in Fig. 1 and 6 the right turning point) is moved, there reverses the direction of movement and at the end of the laying cycle is again reached at the front reversal point U ₀ . The outward journey of the laying carriage 10 between the reversal points U ₀ and U ₁ takes place in the period t ₁ -t ₀ , while the return journey of the laying carriage 10 takes place between the reversal points U ₁ and U ₀ in the period t ₂ -t ₁ . The reversal points U ₀ and U _{1 of} the laying carriage 10 are each defined in terms of space and define the laying width of the web layer 2. The laying width of the web layer 2 may understandably not be changed during operation. This also applies to all the following considerations. For web formation many consecutive lay cycles are necessary.

In this case, assuming that there is no additional distortion of the card web 6 within the web layer 2 between the uppercarriage 30 and the laying carriage 10, the following equations apply to the superstructure speed U at any given time: $$\mathrm{One\; Way}:U=\frac{1}{2}V\mathrm{return\; journey}:U=\frac{1}{2}V+W$$

Fig. 2 shows as an example the speed profiles in a crosslapper at constant Floreinlaufgeschwindigkeit V. Since the superstructure 30 always runs during the outward journey of the laying carriage 10 at the half pile entrance velocity V towards the rear, the speed U of the superstructure 30, during the outward journey of the laying carriage 10 is also constant. The speed W of the laying carriage 10, however, initially undergoes a linear increase on the outward journey of the laying carriage 10 until a plateau of speed is reached, whereupon the laying carriage 10 is decelerated and finally at the rearward reversing point U ₁ (in the illustrated example at t ₁ = 2, 10 s) the direction changes. In normal operation of a conventional nonwoven layer 2, the two subsections of the speed profile of the carriage carriage speed W on return trip are identical except for the sign, ie the average of the speed amount of the carriage 10 on its outward journey (time period t ₁ -t ₀ ) corresponds to the average of the speed amount of the laying carriage 10 on its return journey (period t ₂ -t ₁ ). In other words, the movement of the laying carriage 10 is synchronous on its outward journey and its return journey. Expressed in a formula, this relationship is: $$\frac{\underset{t_0}{\overset{t_1}{\int }}\left|W\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}=\frac{\underset{t_1}{\overset{t_2}{\int }}\left|W\left(t\right)\right|\mathit{dt}}{t_2-{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_1}$$

The superstructure 30 continues a little further, after the laying carriage 10 has already reached its reversal point U ₁ , then brakes as well and will arrive shortly after the laying carriage 10 at its rear-side reversal point U ₃ , whereupon it is linearly accelerated in the opposite direction, until it reaches a speed that is greater in magnitude than the constant speed on the outward journey. This speed plateau then returns to a deceleration phase, which ends at the front reversal point U ₂ , and then again into an opposite acceleration of the superstructure 30 is reversed. The superstructure 30 thus reaches its front reversal point U _{2 in} terms of time, before the laying carriage 10 reaches its front reversal point U ₀ . This is followed by a new lay cycle.

Of course, there are various possible variations of the speed profiles, in particular with regard to the amount of acceleration, length of the plateau phases etc. However, all conventional speed profiles have in common that the average of the speed amount of the superstructure speed U during the outward journey of the laying carriage 10 (ie while the laying carriage 10 from the front reversal point U ₀ to the rear-side reversal point U ₁ moves) always corresponds to half the average of the speed amount of the Floreinlaufgeschwindigkeit V. Expressed in a formula, this means: $$\frac{\underset{t_0}{\overset{t_1}{\int }}\left|U\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}=\frac{1}{2}\frac{\underset{t_0}{\overset{t_1}{\int }}\left|V\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}$$

Likewise, during the outward journey of the laying carriage 10, the average of the speed amount of the laying carriage 10 is twice as high as the average of the speed amount of the upper carriage 30 in the same period. Expressed in a formula, this means $$\frac{\underset{t_0}{\overset{t_1}{\int }}\left|W\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}=2\frac{\underset{t_0}{\overset{t_1}{\int }}\left|U\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}$$

Expressed in concrete figures, the speed U of the superstructure is 30 in the case of the example Fig. 2 during the outward journey of the laying carriage constant at 50 m / min, while the average of the speed amount of the speed W of the laying carriage 10 during its outward journey is 100 m / min and thus corresponds to the average pile run velocity V. On the return journey of the laying carriage 10, the average of the speed amount of the laying carriage speed W is also 100 m / min. It can be seen that the laying width, which in the present case is 3.5 m, was traveled once in both directions by the laying carriage after a time of 4.20 seconds.

All of the above-described formula-related relationships also apply to the conventional operation of a webbed 2 with fluctuating Floreinlaufgeschwindigkeit V.

In Fig. 3a Now, an example of the operation according to the invention of a nonwoven layer 2 is shown. It is essential in this case firstly that the pile infeed speed V is configured variably due to the upstream connection of the device 52 for changing the Florlaufgeschwindigkeit and shows a hill and valley profile. The speed U of the superstructure 30 is during the outward journey of the laying carriage 10, so while the laying carriage 10 moves from the front reversal point U ₀ to the rear reversal point U ₁ , again half as high as the Floreinlaufgeschwindigkeit V and therefore has the amount of half reduced, but the profile profile identical speed profile as the Floreinlaufgeschwindigkeit V. The laying carriage 10 is initially accelerated more on its outward journey and reaches a speed plateau, which is higher than in the case of continuous Floreinlaufgeschwindigkeit V. Also the deceleration process towards the rear reversal point U ₁ is faster , whereupon an acceleration process of the carriage 10 follows in the opposite direction, which in turn merges into a speed plateau. Subsequently, the laying carriage 10 is braked in the direction of the front reversal point U ₀ . It is noticeable and particularly relevant here that the increase in the average of the speed amount of the laying carriage speed W during the outward journey of the laying carriage 10 is greater than during its return journey. This asynchronous increase of the laying carriage speed W is an essential feature and ensures that the travel path of the upper carriage 30 is limited. Expressed in a formula, this means: $$\frac{\underset{t_0}{\overset{t_1}{\int }}\left|W\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}>\frac{\underset{t_1}{\overset{t_2}{\int }}\left|W\left(t\right)\right|\mathit{dt}}{t_2-{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_1}$$

Likewise, this means that the average of the speed amount of the carriage carriage speed W on the outward journey of the laying carriage 10 is greater than twice the average of the speed amount of the superstructure speed U during the outward journey of the laying carriage 10. The laying carriage 10 thus travels on average during its outward journey more than twice as fast as the superstructure 30 and catch up with it earlier than in synchronous operation. In a formula, this means: $$\frac{\underset{t_0}{\overset{t_1}{\int }}\left|W\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}>2\frac{\underset{t_0}{\overset{t_1}{\int }}\left|U\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}$$

As can be seen clearly from the graph, a lay cycle now only takes about 3.80 s, which is logical due to the mass flow constancy. In this context, mass flow constancy means that, on average, the average pile run speed V should correspond to the average laying carriage speed W. Due to the fixed width of 3.5m, this inevitably results in a shorter lay cycle. It is essential to the invention, however, that the laying carriage reaches the rear-side reversal point U ₁ already after approximately 1.80 seconds and thus significantly before half the duration of a laying cycle.

In the example of the Fig. 3a The following specific values result: Average of the speed amount of the laying carriage 10 on its outward journey: 116 m / min; Average of the speed of the carriage 10 on its return: 107 m / min; and average of the speed amount of the superstructure 30 during the outward journey of the laying carriage 10: 55 m / min.

In Fig. 3b the resulting track l of the superstructure 30 is shown graphically (in meters). This lays exactly 1.90 m between its front reversal point U ₂ and the rear reversal point U ₃ .

Fig. 4a shows another example of a velocity distribution according to the invention in the operation of a nonwoven layer 2. The example is similar to that in FIG Fig. 3a Example shown, but with the difference that the acceleration phases and deceleration phases of the laying carriage 10 are even steeper and the speed plateaus correspondingly longer fail, but at a slightly lower level than in the example of Fig. 3a , In the example of Fig. 4a the following values result: average of the speed amount of the laying carriage 10 on its outward journey: 114 m / min; Average of the speed of the carriage 10 on its return: 108 m / min; and Average of the speed amount of the superstructure 30 during the outward journey of the laying carriage 10: 55 m / min.

The associated Fahrwegdiagramm of the superstructure 30 in Fig. 4b shows that the superstructure 30 again covers a lane l of 1.90 m.

Finally, in Fig. 5a Yet another example of the velocity profiling according to the invention in the fleece layer 2 is shown. In this case, the average of the speed amount of the laying carriage speed W during the return journey of the laying carriage 10 is higher than during its outward journey. The following formula therefore applies: $$\frac{\underset{t_0}{\overset{t_1}{\int }}\left|W\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}<\frac{\underset{t_1}{\overset{t_2}{\int }}\left|W\left(t\right)\right|\mathit{dt}}{t_2-{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_1}$$

Likewise, the average of the speed amount of the laying carriage 10 on its outward journey is less than twice the average of the speed amount of the superstructure 30 during the outward journey of the laying carriage 10. Mathematically speaking, one obtains: $$\frac{\underset{t_0}{\overset{t_1}{\int }}\left|W\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}<2\frac{\underset{t_0}{\overset{t_1}{\int }}\left|U\left(t\right)\right|\mathit{dt}}{t_1-{\mathrm{<figure-callout\; id="0"\; label="t"\; filenames="imgf0002.png,imgf0003.png"\; state="\{\{state\}\}">t</figure-callout>}}_0}$$

In detail arise in the example of the Fig. 5a following values: average of the speed amount of the carriage 10 on its outward journey: 106 m / min; Average speed of the carriage 10 during its return: 117 m / min; and average of the speed amount of the superstructure 30 during the outward journey of the laying carriage 10: 56 m / min.

The associated travel diagram of the superstructure 30 is in Fig. 5b shown. It can be seen that the track l of the superstructure 30 is slightly extended to 1.96 m. However, in this case not a shift of the rear-side reversal point U ₃ , but the front-side reversal point U ₂ (in the case of Fig. 1 and 6 so to the left), which has no consequences for the spatial extent of the fleece layer 2, since the upper carriage 30 at the front anyway only reaches the middle of the fleece layer 2. One must, however, make sure that the superstructure 30 does not collide with other parts, such as the clamping carriage 40.

Overall, however, the embodiments are preferred in which the laying carriage 10 on its outward journey on average drives faster than on its return journey. In this case can be completely dispensed with a prolonged upcar drive.

It is particularly preferred if two predetermined reversal points U ₂ , U _{3 are} spatially defined for the superstructure 30, and the profile of the speed W of the laying carriage 10 is set such that the superstructure 30 does not exceed the predetermined reversal points independently of the variable pile infeed speed V U ₂ , U ₃ goes out.

Overall, there are various possibilities for designing the velocity profiles. These may also contain more stages than in the previous examples, e.g. also short-term increases in the plateau area of the laying carriage speed. In addition, in all examples, the speed profiles are set so that after completion of a laying cycle already back to the initial state is established and thus a speed compensation of the variable Floreinlaufgeschwindigkeit V is completed. It is also possible to achieve this goal after several laying cycles, so for example to set the average speed of the laying carriage 10 on his outward journey in the first laying cycle very high and compensate for this difference only in the course of several returns in the subsequent laying cycles. It is equally conceivable that after an asynchronous laying cycle according to the invention, several normal laying cycles with synchronous laying carriage speed profile follow.

According to the previous embodiments, a total of two pile conveyor belts 16, 36 are contained in the fleece layer 2. The invention can also be applied to other fleece layers with two pile conveyor belts, as well as to all other nonwoven layers configured as co-travelers, inter alia those with three tapes. An example of such a fleece layer with three pile conveyor belts is in Fig. 6 shown. At the in Fig. 6 The illustrated nonwoven layer is the second pile conveyor belt 16 of the embodiment Fig. 1 replaced by a second pile conveyor belt 70 and a third pile conveyor belt 72, which are deflected in a common tensioning carriage 74.

Claims (5)

1. Method for operating a non-woven fabric laying device (2) for laying a non-woven fabric from a card web with the following steps:

   setting up a non-woven fabric laying device (2) with
   an upper carriage (30) which can be moved in the transverse direction and through which a card web (6) which is produced by a card web generator is guided, a laying carriage (10) movable in the transverse direction and through which the card web (6) coming from the upper carriage (30) is guided and which serves to deliver the card web (6) onto an output conveyor belt (4), and with at least two card web transport belts (16, 36, 70, 72) for guiding the card web (6) in the non-woven fabric laying device towards the laying carriage (10);
   setting up a device (52), which is connected in in front of the non-woven fabric laying device (2) and is integrated in the inlet area thereof, for temporarily changing a speed of the card web (6), whereby the card web (6) is supplied to the non-woven fabric laying device (2) with variable card web inlet speed (V);
   wherein the upper carriage (30) and the laying carriage (10) are moved to and fro in a laying cycle substantially in the same direction by means of forward and back travel, wherein the laying carriage (10) in each laying cycle is moved to and fro between two fixedly defined reversing points (U₀, U₁),

   characterised in that the average amount of the laying carriage speed (W) on the to (forward) movement of the laying carriage (10) in each laying cycle or at least in several laying cycles is different from the average amount of the laying carriage speed (W) on the return movement of the laying carriage (10), and that the average amount of the laying carriage speed (W) in each laying cycle or at least in several laying cycles during the forward movement of the laying carriage (10) is different from twice the average amount of the upper carriage speed (U) during the forward movement of the laying carriage (10).
2. Method according to claim 1 characterised in that the average amount of the laying carriage speed (W) on the forward movement of the laying carriage (10) in each laying cycle or at least in some laying cycles is greater than double the average amount of the upper carriage speed (U) during the forward movement movement of the laying carriage (10), and that the average amount of the laying carriage speed (W) on the forward movement of the laying carriage (10) in each laying cycle or at least in some laying cycles is greater than the average amount of the laying carriage speed (W) on the return movement of the laying carriage (10).
3. Method according to claim 2 characterised in that the average amount of the laying carriage speed (W) after several laying cycles corresponds to the average amount of the variable card web inlet speed (V).
4. Method according to claim 3 characterised in that the average amount of the laying carriage speed (W) after each laying cycle corresponds to the average amount of the variable card web inlet speed (V).
5. Method according to one of the preceding claims characterised in that two predetermined reversing points (U₂, U₃) are defined spatially for the upper carriage (30), and that a profile of the speed (W) of the laying carriage (10) is adjusted so that the upper carriage (30) does not extend beyond the predetermined reversing points (U₂, U₃) irrespectively of the variable card web inlet speed (V).

Images