Output Conveyor Belt of a Crosslapper

Abstract

The output conveyor belt of a crosslapper for holding and conveying layers of card web laid to form a nonwoven is configured as an endless slatted belt with a plurality of transverse slats. The transverse slats comprise support surfaces for the nonwoven, which are formed by fibers or bristles projecting from the transverse slats.

Claims

1. An output conveyor belt of a crosslapper for holding and conveying layers of card web laid to form a nonwoven, wherein the output conveyor belt is configured as an endless slatted belt with a plurality of transverse slats, wherein the transverse slats comprise support surfaces for the nonwoven, and wherein at least certain areas of the support surfaces of at least some of the transverse slats are formed by fibers or bristles projecting from the transverse slats.

2. The output conveyor belt according to claim 1 wherein the transverse slats are covered at least partially by a covering, which comprises projecting fibers or bristles.

3. The output conveyor belt according to claim 2 wherein the covering comprises a backing layer, from which the fibers or bristles project.

4. The output conveyor belt according to claim 3 wherein the fibers project from the backing layer over a distance in the range of 0.5-5 mm.

5. The output conveyor belt according to claim 2 wherein the covering is formed of pile fabric with projecting fibers.

6. The output conveyor belt according to claim 5 wherein the pile fabric is a velvet or a velour.

7. The output conveyor belt according to claim 3 wherein the fibers are applied in the form of fiber flocking to the backing layer.

8. The output conveyor belt according to claim 3 wherein the backing layer comprises at least one adhesive layer.

9. The output conveyor belt according to claim 2 wherein each transverse slat is covered by the covering.

10. The output conveyor belt according to claim 2 wherein every second or every third transverse slat is covered by the covering.

11. The output conveyor belt according to claim 1 wherein the transverse slats are equipped with the fibers or bristles over an entire width of the output conveyor belt.

12. The output conveyor belt according to claim 2 wherein the transverse slats comprise a covering in outer areas of the output conveyor belt, whereas the transverse slats are not covered by the covering in a middle area.

13. The output conveyor belt according to claim 12 wherein the middle area not provided with the covering extends over no more than 70% of the width of the output conveyor belt.

14. The output conveyor belt according to claim 12 wherein the middle area not provided with the covering extends over no more than 60% of the width of the output conveyor belt.

15. The output conveyor belt according to claim 12 wherein the middle area not provided with the covering extends over no more than 50% of the width of the output conveyor belt.

16. The output conveyor belt according to claim 1 wherein the bristles are present in the form of bristle bundles.

17. The output conveyor belt according to claim 16 wherein the bristles are attached directly to the transverse slats.

18. The output conveyor belt according to claim 1 wherein a cleaning device is arranged in an area of the output conveyor belt to remove adhering fibers of the nonwoven.

19. The output conveyor belt according to claim 18 wherein the cleaning device comprises a brush roller and/or a suction device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 shows a schematic side view of a crosslapper with an embodiment of an output conveyor belt according to the invention;

[0020] FIG. 2 shows a schematic top view of an output conveyor belt, in which an undesirable contraction of the edges of the nonwoven is illustrated schematically;

[0021] FIG. 3 shows a perspective view of part of an upper run of an embodiment of an output conveyor belt according to the invention;

[0022] FIG. 4 is a cross-sectional view of a configuration of a transverse slat of the output conveyor belt with covering as in FIG. 3; and

[0023] FIG. 5 is a cross-sectional view of an alternative configuration of a transverse slat of the output conveyor belt with bristle bundles.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0024] FIG. 1 shows a schematic view of a crosslapper 2, with the end of an output conveyor belt 4 facing the observer. The endless output conveyor belt 4 is designed to carry away a laid nonwoven 3 in a transport direction T (see FIG. 3), which is perpendicular to the plane of the drawing. Above the output conveyor belt 4, a laying carriage 6 can be moved back and forth on rails or tubes 8. In the laying carriage 6, a laying nip for the card web (not shown) is formed between two rollers 10, 12. The card web is guided through crosslapper 2 to this laying nip by at least two card web transport belts 14, 16. In the present example, crosslapper 2 is configured as a horizontal layer, in which an upper carriage 18 is arranged substantially on the same level as laying carriage 6 and is also supported movably back and forth transversely to the transport direction of the output conveyor belt 4 on rails or tubes 8. Rails or tubes 8 can be the same rails or tubes on which laying carriage 6 is also movably supported. In operation, when laying carriage 6 is executing a back-and-forth movement above output conveyor belt 4, upper carriage 18 moves in the same direction but more slowly.

[0025] The movements of laying carriage 6 and of upper carriage 18 are coordinated with each other in such a way that, as the card web is being fed into crosslapper 2, layers of card web can be deposited onto output conveyor belt 4 in a controlled manner within the illustrated crosslapper 2. As this is happening, upper carriage 18 moves in the same direction as laying carriage 6 but on average only half as fast. It is also taken into account that laying carriage 6 must be braked to a halt and then accelerated again in the area of its reversal point. If the card web enters at varying speeds, perhaps because a stretching device (not shown), in particular a cyclically operating web drafter, is installed upstream of crosslapper 2 to produce a varying thickness in the card web for the purpose of achieving a transverse profiling of laid nonwoven 3, a card web buffering zone can be provided within crosslapper 2 in a known manner by controlling the movement of upper carriage 18 and the movement of laying carriage 6 independently of each other. It is also possible to draft the card web within crosslapper 2 by coordinated movements of upper carriage 18 and laying carriage 6.

[0026] According to the exemplary embodiment shown in FIG. 1, three card web conveyor belts are present in crosslapper 2 in addition to output conveyor belt 4. The invention can also be applied, however, to any other type of crosslapper, including those with two card web conveyor belts. The invention can also be applied to contrary-motion crosslappers, in which upper carriage 18 and laying carriage 6 move in opposite directions and also to camelback crosslappers.

[0027] Common to all crosslappers 2 is that laying carriage 6 must be braked to a halt and then accelerated again in the opposite direction at its reversal points. During the braking and accelerating phase, the speed of card web deposition is also reduced correspondingly in modern crosslappers 2 in order to prevent the edges of the laid nonwoven 3 from becoming too thick. At the same time, output conveyor belt 4 is adapted in a controlled manner to these cyclic movements and therefore also becomes correspondingly slower at the times when laying carriage 6 is braked to a halt and accelerated again in the opposite direction. This is necessary to guarantee that the layers of card web line up precisely at the edges of the nonwoven. The speed of output conveyor belt 4 can drop to zero. Overall, therefore, output conveyor belt 4 moves in cyclical fashion with variable speed patterns.

[0028] As shown in FIG. 2, during the zigzag deposition of the card web layers 5 onto output conveyor belt 4, it is possible for the most recently laid card web layer 5 to contract undesirably as previously described as a result of the intrinsic stress in the fiber material.

[0029] According to the invention, however, it would be desirable to change the configuration shown in FIG. 2 in such a way that all of the card web layers 5 extend over the same width, i.e., over the starting width shown at the bottom of FIG. 2.

[0030] A first embodiment of output conveyor belt 4 according to the invention used for this purpose is illustrated in FIGS. 3 and 4. Another embodiment is shown in FIG. 5.

[0031] FIG. 3 shows part of the upper run of endless output conveyor belt 4. Output conveyor belt 4 is configured as an endless slatted belt with a plurality of transverse slats 20. Transverse slats 20 are preferably made of plastic.

[0032] The nonwoven 3 lies on the support surfaces 22 of transverse slats 20 in the area of the upper run of output conveyor belt 4. Each of the support surfaces 22 of transverse slats 20 is covered by a covering 24, which is shown in black in FIG. 3. At the outermost edge areas of output conveyor belt 4, there are usually strips onto which a nonwoven 3 is not laid. Here there is no need for covering 24, as shown in FIG. 3. It is also conceivable that the transverse slats 20 could be covered by covering 24 over their entire length.

[0033] Finally, it is also conceivable that a covering 24 could be present in outer areas of the transverse slats 24, possibly aside from unused edge strips, whereas no covering 24 is provided in a middle area of transverse slats 20. The free middle area extends over no more than 70% of the width of output conveyor belt 4. Nonwoven 3 lies on and is held by covering 24 both by friction and by positive interlocking.

[0034] In other embodiments, not every transverse slat 20 needs to be provided with a covering 24. This is advantageous for economic reasons. Instead, it is possible for only every second, third, fourth, or fifth transverse slat 20 to be provided with a covering 24.

[0035] Output conveyor belt 4 is usually connected to at least one drive roller (not shown) by a toothed engagement and also travels around deflecting rollers. In an area of output conveyor belt 4 outside the nonwoven laying section, preferably in the area of the lower run of output conveyor belt 4, a cleaning device (not shown) for removing adhering fibers of nonwoven 3 is preferably arranged. The cleaning device can, for example, comprise a brush roller and/or a suction device.

[0036] Transverse slats 20 are covered at least partially by a covering 24, which comprises projecting fibers 32. Covering 24 could also comprise projecting bristles. In this way, at least certain areas of support surfaces 22 of at least some of transverse slats 20 are formed by the fibers 32 or bristles projecting from transverse slats 20. Covering 24 usually comprises a backing layer 26, from which the fibers 32 or bristles project.

[0037] In most cases covering 24 thus comprises fibers 32, possibly also in the form of filaments or yarns, which extend from backing layer 26 and project into the third dimension. In especially preferred embodiments, the material of covering 24 is a pile fabric. Pile fabric generally comprises at least some vertically oriented fibers 32 and/or fibers 32 with a nap (slanted orientation). Velvets and velour materials, for example, are examples of pile fabrics.

[0038] Coverings 24 which can also be considered include Raschel materials, tufted materials, woven materials, or knitted or machine-knitted materials, provided that fibers 32 project upward from them.

[0039] Finally, it is also conceivable that projecting fibers 32 could be applied in the form of a fiber flocking to backing layer 26. In this case, plastic, wood, metal, or a textile layer can be considered as backing material.

[0040] All of fibers 32 are short fibers, which project from backing layer 26 over a distance in the range of 0.5-5 mm, preferably over a distance of 1.0-4.0 mm.

[0041] Bristles, however, are considerably longer and project from backing layer 26 over a distance in the range of 5-50 mm. FIG. 4 shows an example of one possible way in which covering 24 can be attached to a transverse slat 20 of output conveyor belt 4. Covering 24 is attached by adhesion to transverse slat 20 by adhesive layer provided on backing layer 26. In addition, covering 24 is also held positively in place by a sealing cord 28 fitted into recesses 30 in transverse slat 20.

[0042] It is obvious that the skilled person will be aware of many other options for attaching covering 24 to transverse slat 20. For example, it can be attached by an adhesive only, by screws, or by both screws and an adhesive.

[0043] FIG. 5 shows an alternative embodiment of a transverse slat 20, in which bristles 34 in the form of bristle bundles are attached directly to transverse slat 20. When bristles 34 are used, therefore, it is not necessary for a backing layer 26 to be present. The bristle bundles can be attached to the transverse slat by mechanical fixation and/or adhesion. It is important that a sufficient number of bristles be provided in a density sufficient to ensure that support surface 22 formed by bristles 34 for the nonwoven does not allow nonwoven 3 to sag too much.

[0044] Bristles 34 project from transverse slat 20 over a distance in the range of 5-50 mm.