Patent Grant
10145032
This application claims priority based on European Patent Application No. EP 14 190 497.9, filed Oct. 27, 2014 and to EP patent Application No. EP 15 187 645.5, filed Sep. 30, 2015, the contents of which are incorporated by reference in their entireties.
The present invention relates to cross lappers for forming nonwovens from fiber webs.
Cross lappers serve to lay multiple layers of a fiber web supplied by a carding machine uniformly on an output conveyor belt. The fiber web is usually sent through an upper carriage first and from there to a laying carriage, through the laying nip of which the fiber web is laid onto the output conveyor belt. To guide the fiber web through the cross lapper, at least two fiber web conveyor belts are used. The movements of the web conveyor belts, of the upper carriage, and of the laying carriage are controlled in coordination with each other.
In the area extending from the infeed area of the cross lapper to the upper carriage, it is advantageous for the fiber web not only to rest on the web conveyor belt but also to be sandwiched from above by a cover belt. The purpose of this is to prevent the fiber web from being blown about and thus to ensure the uniformity of the laid nonwoven. Structures of this type are known from DE 195 43 623 A1, EP 1 136 600 A1, and EP 1 870 499 B1, for example. The disadvantage of these cross lapper designs is the complexity with which the endless cover belt must be guided, which requires a large number of components and considerable mechanical effort.
EP 2 479 321 A1 discloses a simplified configuration of cross lapper, in which the cover belt is smooth and does not move along with the fiber web. Instead, it serves as a more-or-less stationary cover for the fiber web. To ensure that the cover belt covers the fiber web on the web conveyor belt for as long as possible, the cover belt runs from an attachment point in the infeed area of the cross lapper, through the upper carriage, to a second attachment point at the other end of the cross lapper.
The disadvantage of this configuration is that, when the cover belt slides through the upper carriage, high relative speeds are reached between the stationary cover belt and the upper carriage as it travels back and forth in the transverse direction. This results in severe stress on the cover belt and increased wear, especially in the area of the reversal point of the upper carriage.
It is an object of the present invention to provide a cross lapper in which the supplied fiber web is guided securely and the forces acting on the cover are reduced.
According to an aspect of the invention, the cross lapper for forming a nonwoven from a fiber web comprises a transversely movable upper carriage, through which the fiber web is guided, and also a transversely movable laying carriage, through which the fiber web coming from the upper carriage is guided, and which serves to lay the fiber web on an output conveyor belt. The cross lapper also comprises at least two web conveyor belts for guiding the fiber web to the upper carriage and then to the laying carriage, wherein a first endless web conveyor belt, the upper run of which extends from the infeed area of the cross lapper to the upper carriage and serves as a support surface for the fiber web, is configured as a rough web conveyor belt and carries by friction the fiber web resting on it. Above the upper run of the first web conveyor belt, a cover section for covering the top surface of the fiber web resting on the upper run of the first web conveyor belt is arranged, wherein the cover section is configured as a section of the cover belt or as a section of an array of linear elements arranged a certain distance apart and parallel to each other. The cover belt or the linear elements are smooth, and the fiber web moves along the bottom surface of the cover section. The first end section of the cover belt or of the array of linear elements is connected to the upper carriage, and the cross lapper also comprises a compensating mechanism to compensate for the changes in the length of the cover section which occur as the upper carriage travels transversely back and forth.
This configuration reduces the wear on the cover belt or on the linear elements in a manner which is both structurally simple and low in cost, wherein in addition it is ensured that the fiber web is guided securely without being blown about.
The cross lapper preferably comprises a tension carriage, which is transversely movable back and forth in the direction opposite to that of the upper carriage. The tension carriage is a component of the compensating mechanism and is connected to the second end section of the cover belt or array of linear elements. As a result, the compensation for the change in length of the cover section which occurs as the upper carriage travels in the transverse direction can be achieved by an especially simple mechanism.
It is especially preferable for the cover belt or the array of linear elements to be deflected in the infeed area of the cross lapper and for at least the second end section of the cover belt or of the array of linear elements to be guided substantially parallel to the upper run of the first web conveyor belt up to an attachment point on the tension carriage and to be fastened to this attachment point. This embodiment is especially suitable for obtaining a compensating mechanism which is both compact and simple in design.
The attachment point is preferably formed on a rail, and it is also preferable for the tension carriage to be arranged under the upper run of the first web conveyor belt and for the rail to be arranged between two tension brackets, which are attached to the sides of the tension carriage and project upward from it beyond the upper run of the first web conveyor belt. With a concrete implementation of this type, the same tension carriage can be used both to compensate for the changes in length of the cover section and to keep the length of the loop of the first web conveyor belt constant as the upper carriage moves transversely back and forth. This represents a low-cost solution which leads to no additional cost for open-loop or closed-loop control, and the structural complexity of arrangement is significantly reduced.
So that the fiber web can be prevented as completely and effectively as possible from being blown about, it is also advantageous for at least one first fiber web guide means to be provided in a section between the attachment point of the first end section of the cover belt or of the array of linear elements in the upper carriage and the point where the fiber web is transferred to the second web conveyor belt. This guide means guides the fiber web in this section, wherein the fiber web is sandwiched between the at least one first fiber web guide means and the first web conveyor belt. It is especially preferable for the attachment point of the first end section of the cover belt or of the array of linear elements in the upper carriage to be a component of the first fiber web guide means. Sandwiched between the cover section or the first fiber web guide means on one side and the first web conveyor belt on the other side, the fiber web therefore is covered continuously, as a result of which it is possible to achieve very high line speeds.
In a preferred embodiment, at least one second fiber web guide means is provided in a section of the infeed area extending up to a point at which the fiber web is sandwiched between the first web conveyor belt and the cover section. This second guide means guides the fiber web in this section, wherein the fiber web is sandwiched between the at least one second fiber web guide means and the first web conveyor belt. As a result, it is possible to prevent the fiber web from being blown about in the infeed area as well as at high web infeed speeds.
The cover belt is preferably air-permeable, so that entrained air, for example, can escape from the fiber web.
In many cases it can also be advisable for the cover belt to be impermeable to air, so that it can be ensured that the fiber web is covered and guided by the cover belt in an especially secure manner.
So that the surface of the cover is as smooth and wear-resistant as possible, the cover belt is preferably made of a fabric carrier coated with either Teflon™ (polytetrafluoroethylene) or PVC (polyvinylchloride), both of which are well known in the art.
When an air-impermeable cover belt is present, it is especially advantageous for the first web conveyor belt to be air-permeable. In this way, the air being carried along by the fiber web can effectively escape in a downward direction and the fiber web is prevented from being blown about.
When an array of linear elements is used, the linear elements are preferably formed as cords, yarns, stranded wires, solid wires, or narrow belts.
The drawings illustrate preferred embodiments including the above-noted characteristics and features of the device. The device will be readily understood from the descriptions and drawings. In the drawings:
Above the output conveyor belt 4, a laying carriage 10 is movable back and forth on rails or pipes (not shown). Five freely rotatable deflection rollers 11, 12, 13, 14, 15 are supported in the laying carriage 10. The first deflection roller 11 and the fifth deflection roller 15 are partially wrapped by the first web conveyor belt 20, wherein this belt is deflected in such a way that it leaves the laying carriage 10 above a third web conveyor belt 24. The fourth deflection roller 14 is partially wrapped by a second web conveyor belt 22, which runs between the upper carriage 30 and the laying carriage 10 very close to the first web conveyor belt 20; it is deflected by 180° around the fourth deflection roller 14 and is then led back, close to the output conveyor belt 4, over several stationary deflection rollers mounted in the machine stand, to the upper carriage 30. The deflection rollers 12 and 13 in the laying carriage 10 are partially wrapped by a third web conveyor belt 24, which also runs a short distance above the output conveyor belt 4 and returns by way of several stationary deflection rollers in the machine stand to the laying carriage 10. In the embodiment of a cross lapper shown here with three web conveyor belts, the second and third web conveyor belts 22, 24 reverse direction in a common tension carriage 80 in an area underneath the output conveyor belt 4. The person skilled in the art is familiar with many other embodiments of cross lappers with two or more web conveyor belts, which are adapted to the laying of nonwovens on an output conveyor belt 4 and in which the arrangement and guidance of the web conveyor belts and the arrangement and number of deflection rollers in the laying carriage 10 and in the machine stand are variable.
A chain or toothed belt, which runs over a pinion gear drive connected to a motor, and a deflection roller (these elements not shown) are mounted on the laying carriage 10. By means of these drive devices, the laying carriage 10 can be moved back and forth above the output conveyor belt 4 transversely to the conveying direction of the output conveyor belt 4.
At approximately the same height as the laying carriage 10, the upper carriage 30 is supported on rails or pipes (not shown) so that it can move transversely to the conveying direction of the output conveyor belt 4 in the machine stand of the cross lapper 2. The rails or pipes can be the same rails or pipes on which the laying carriage 10 is also movably supported. The upper carriage 30 has a deflection roller 32, around which the first web conveyor belt 20 is deflected so that it is then parallel to the second web conveyor belt 22 and can proceed toward the laying carriage 10.
Proceeding from the deflection roller 32 in the upper carriage 30, the first web conveyor belt 20 runs through the laying carriage 10 and from there is guided over several deflection rollers in the machine stand and a deflection roller mounted in a tension carriage 50, whereupon it runs over several stationary deflection rollers supported in the machine stand of the cross lapper 2 above the tension carriage 50 before it arrives back at the upper carriage 30. The upper carriage 30 and the tension carriage 50 can be connected to each other by a chain or a toothed belt (not shown), which runs over a pinion gear drive connected to a motor (not shown) and a deflection roller (not shown), which are supported in the machine stand. The tension carriage 50 is also movably supported on rails or pipes (not shown).
In the area between the deflection roller 32 of the upper carriage 30 and the deflection rollers 14 and 15 of the laying carriage 10, sections of the first web conveyor belt 20 and of the second web conveyor belt 22 are guided parallel to, and a very short distance away from, each other, so that a fiber web 6 supplied by the first web conveyor belt 20 is sandwiched between the first web conveyor belt 20 and the second web conveyor belt 22 in said area between the upper carriage 30 and the laying carriage 10. The fiber web 6 is supported by the second web conveyor belt 22. In addition, the two sections of the second web conveyor belt 22 extending between the laying carriage 10 and the machine stand of the cross lapper 2 simultaneously serve the function of a cover belt for the laid nonwoven.
It can be seen in
The movements of the laying carriage 10 and of the upper carriage 30 are coordinated with each other in such a way that, as the fiber web 6 is being fed at uniform speed to the cross lapper 2, the fiber web 6 can be laid in a controlled manner on the output conveyor belt 4 without being stretched or compressed inside the cross lapper 2. During this process, the upper carriage 30 always moves in the same direction as the laying carriage 10, but, on average, at only half its speed. Account is also taken of the fact that the laying carriage 10 must be braked almost to a stop and then accelerated again in the area of its reversal points. If the fiber web 6 is being fed at a fluctuating speed because, for example, a cyclically operating web drafter (not shown), which produces changes in the weight per unit area of the fiber web 6 for the purpose of creating a transverse profiling of the laid nonwoven, is installed upstream of the cross lapper 2, the movements of the upper carriage 30 and of the laying carriage 10 can be controlled independently of each other in the known manner to create a storage buffer for the fiber web inside the cross lapper 2.
Between the deflection rollers 13 and 14 in the laying carriage 10, a gap is formed, called the “laying nip”. During the operation of the cross lapper 2, the two web conveyor belts 22, 24 are driven in such a way that they travel at the same speed. The fiber web 6 is guided through the laying nip and laid onto the output conveyor belt 4.
The cross lapper 2 in
As a result of frictional forces, the endless first web conveyor belt 20 carries along the fiber web 6 resting on it, and the cover section 40 of the cover belt 26, which does not move along with the fiber web 6, serves as a cover and thus prevents the fiber web 6 from being blown about, which is undesirable. The fiber web 6 thus remains almost completely free of turbulence, as a result of which higher line speeds can be realized. In other words, the fiber web 6 is sandwiched between the upper run 21 of the first web conveyor belt 20 and the cover section 40 of the cover belt 26, wherein it is moved forward primarily by the movement of the first web conveyor belt 20, and the smooth cover belt 26 does not impede the movement of the fiber web 6.
In the upper carriage 30, the first end section 27 of the cover belt 26 is connected to the upper carriage 30 at an attachment point. As can be seen in
A compensating mechanism (not shown) serves to compensate for the changes in the length of the cover section 40 of the cover belt 26 which occur as the upper carriage 30 moves transversely back and forth.
In the preferred embodiment shown here, the cover belt 26 is conducted upward in the infeed area 8 of the cross lapper 2, away from the first web conveyor belt 20 and around the deflection roller 34, so that at least the second section 28 of the cover belt 26 is substantially parallel to the upper run 21 of the first web conveyor belt 20. If the cover belt 26 is also air-permeable, the deflection roller 34 can preferably be configured as a perforated roller.
In the embodiment according to
It is obvious, however, that the person skilled in the art will be able to imagine other ways of implementing the compensating mechanism. For example, the second end section 28 of the cover belt 26 could be rolled up onto a supply roll and pulled back off again, or a separate tension carriage could be provided for the second end section 28. A simple hanging storage buffer for the cover belt 26 or some other type of buffer could also be imagined.
To prevent the fiber web 6 from being blown about as effectively as possible in the infeed area 8 as well, preferably a second fiber web guide means 70 is provided in the area extending from the infeed area 8 to a point at which the fiber web 6 is sandwiched between the first web conveyor belt 20 and the cover section 40 of the cover belt 26. The second fiber web guide means 70 guides the fiber web 6 in this section, wherein the fiber web 6 is thus sandwiched between the second fiber web guide means 70 and the first web conveyor belt 20 The second fiber web guide means 70 extends advantageously from the infeed area 8 of the cross lapper 2 to the deflection roller 34 of the web conveyor belt 26 and as closely as possible to that belt. When configuring the second fiber web guide means 70, the person skilled in the art can borrow ideas from the first fiber web guide means 60, wherein the contour of the second fiber web guide means 70 is to be adapted to the course of the first web conveyor belt 20. Additional suitable fiber web guide means 70 such as cover belt sections, for example, can also be used.
A first end section of the array of linear elements 62 in
The linear elements 62 are arranged a certain distance above the first web conveyor belt 20. They are parallel to each other, extending in the transport direction A of the first web conveyor belt 20, and are arranged next to each other, transversely to the transport direction A, a certain distance apart. The linear elements 62 are preferably held under tension.
In the example shown here, the linear elements 62 are configured as narrow belts, which can be made of, for example, thin high-grade steel, plastic, Teflon, or coated textile material. Cords, yarns, stranded wires, or solid wires of these materials can also be used as linear elements 62. For example, teflonized wires, plastic-coated wires, or high-grade steel wires can be used. The linear elements 62 are preferably non-rigid. In all cases, the linear elements must have a smooth surface, so that the fiber web 6 being carried along on the first web conveyor belt 20 can easily slide along the bottom surface of the linear elements 62.
The width of the individual linear elements is preferably in the range of 1-5 mm. The distance between two linear elements 62 is preferably in the range of 2-50 mm, and especially in the range of 10-30 mm.
When linear elements 62 are used, the air carried along by the fiber web 6 can escape through the intermediate spaces between the individual linear elements 62. To this extent, the first web conveyor belt 20 does not necessarily have to be air-permeable.
In the example shown in
With the configuration of a cross lapper 2 according to the invention, it is possible with little structural effort to realize high line speeds without the risk of the fiber web 6 being blown about undesirably and without causing increased wear of the cover belt 26. In all cases, the frictional force between the fiber web 6 and the first web conveyor belt 20 is greater than the frictional force between the fiber web 6 and the cover (cover belt 26 or array of linear elements 62). The coefficient of friction between the fiber web 6 and the first web conveyor belt 20 is also preferably greater than the coefficient of friction between the fiber web 6 and the cover.
The distance between the cover and the first web conveyor belt 20 depends on the fiber web 6 to be conveyed and is usually in the range of 0.1-100 mm, and preferably in the range of 0.5-5 mm. The height of the cover is preferably adjustable.
The invention is also applicable to opposite-motion cross lappers, in which the upper carriage 30 and the laying carriage 10 move in opposite directions, and also to camel-back cross lappers.
A wide variety of materials are available for the various parts discussed and illustrated herein. While the principles of this device have been described in connection with specific embodiments, it should be understood clearly that these descriptions are made only by way of example and are not intended to limit the scope of the application.
| Number | Date | Country | Kind |
|---|---|---|---|
| 14190497 | Oct 2014 | EP | regional |
| 15187645 | Sep 2015 | EP | regional |
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| 4217285 | Jan 1994 | DE |
| 2479321 | Jul 2012 | EP |
| Number | Date | Country | |
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| 20160115628 A1 | Apr 2016 | US |
