Patent Application
20050022343
1. Field of the Invention
The invention relates to an intermediate card for manufacturing nonwovens of fibrous material according to the precharacterizing part of claim 1 as well as to a method for manufacturing nonwovens of fibrous material according to the precharacterizing part of claim 11.
2. Description of Related Art
Such an intermediate card is known, for example, from European Patent 484 812 A. In this intermediate card, each of two fiber take-off means takes a card web from a main cylinder and deposits it on a respective conveyor belt by means of stuffer and take-off rollers. In the course of this, the conveyor belt of a fiber take-off means transfers a card web onto a conveyor belt of another fiber take-off means so that eventually, all card webs are able to be carried away as a nonwoven on a common conveyor belt.
With several intermediate cards arranged behind each other, it is known from European Patent 817 875 A to deposit the card web of the intermediate card mechanically on a common conveyor belt which is sucked throughout in the region of the card web. Such an installation facilitates the realization of high-speed carding installations permitting production speeds of more than 150 m/min, preferably of more than 200 m/min up into the range of from 400 to 500 m/min.
In the last-mentioned state of the art, the take-off of two card webs from the main cylinder is provided, the card webs being doubled on a common succeeding roller.
It is also known to transfer two card webs taken off from a main cylinder onto a common conveyor belt after each other, said conveyor belt being sucked at the transfer site.
It is the object of the present invention to improve the transfer of repeatedly taken-off card webs onto a common conveyor belt and to permit a more compact structure of an intermediate card.
This object is solved, according to the invention, with the features of claims 1 and 11, respectively.
The invention advantageously provides that each fiber take-off means transfers the taken-off card webs onto transfer sections of a permeable conveying surface curved in a circularly cylindrical manner, said transfer sections being mutually offset in circumferential direction. The circumferential speed of the conveying surface is adapted to the transfer speed of the card webs from the fiber take-off means as to direction and amount, the conveying surface being sucked at the transfer sections.
The invention provides a take-off system in which a guided transfer of individual card webs onto a common parallel conveyor belt is permitted. The permeable conveying surface curved in a circularly cylindrical manner permits a more favorable deposition angle at the transfer sections. The curved surfaces at the transfer sections make it easier to take out the fibers at the take-off roller of the fiber take-off means in connection with the sucking of the conveying surface in the region of the transfer sections. The superposition of the card webs in rapidly succeeding transfer sections also permits a better connection between the upper web and the bottom web as well as a compact construction of the intermediate card. The conveying surface curved in a circularly cylindrical manner permits a transfer of the card webs to the conveyor belt which is poor in distortion, so that higher production speeds are possible.
In one embodiment, it is provided that the permeable conveying surface is formed by a rotating screening drum. The screening drum takes over several card webs at different transfer sections, which are transferred in common onto a permeable conveyor belt of a conveying means at a transfer site where the suction flow into the screening drum is at least interrupted or reversed.
The conveyor belt is adapted to be sucked at the transfer site between the screening drum and the conveyor belt from the side of the conveyor belt opposite the transfer site.
According to another preferred embodiment, it is provided that a permeable endlessly circulating conveyor belt of a conveying means loops a rotating screening drum at least in the region of the transfer sections of the conveying surface and carries away the card webs lying on top of each other and sucked by the screening drum onto the conveyor belt. The speed of the conveyor belt corresponds to the circumferential speed of the rotating screening drum. This embodiment also follows the principle that a curved surface of a last roller of the fiber take-off means transfers the card web onto the permeable conveying surface curved in a circularly cylindrical manner.
Preferably, it is provided that the conveying means is adapted to be pivoted about an axis coaxial to the axis of the screening drum in such a manner that the transfer site of the conveyor belt for the common card web from the conveying means to a succeeding means is height-adjustable.
The fiber take-off means may comprise at least one doffer roller being in engagement with the main cylinder. In another embodiment, it is provided that the fiber take-off means comprises at least one tangling roller being in engagement with the main cylinder, transferring the card web onto at least one doffer roller. One or more fiber take-off means may comprise one tangling roller, respectively, each of which takes over one card web from the main cylinder. From the respective tangling roller of a fiber take-off means, the card web can be transferred to one or more doffer rollers.
Preferably, each doffer roller is in engagement with at least one succeeding stuffing roller and a take-off roller or only a take-off roller.
In a preferred embodiment, it is provided that the drawing-in means with drawing-in rollers and a licker-in comprises at least one tangling roller between the licker-in and the main cylinder, which rotates in the same direction as the main cylinder and the licker-in.
It may also be provided that the fibers are transferred from the licker-in to the main cylinder on at least two paths.
Hereinafter, several embodiments of the invention are explained in detail with reference to the drawings.
In the Figures:
The portion of an intermediate card on the card web take-off side shown in
Each fiber take-off means 6a, 6b is comprised of a doffer roller 8a,8b and at least one take-off roller 12a, 12b, at least one stuffing roller 10a,10b being able to be arranged between the doffer roller 8a,8b and the take-off roller 12a, 12b.
The screening drum 14 forms a permeable conveying surface 15 curved in a circularly cylindrical manner onto which the card webs transferred by the fiber take-off means 6a, 6b can be transferred at transfer sections 15a, 15b circumferentially offset with respect to each other. The transfer sections 15a, 15b are located at the narrowest sites between the take-off rollers 12a, 12b and the conveying surface 15. As to direction and amount, the circumferential speed of the screening drum at its conveying surface is adapted to the transfer speed of the card webs at the transfer sections 15a, 15b. Preferably, the screening drum 14 is sucked in a segment extending from the take-off roller 12a to a transfer site between the screening drum 14 and a conveyor belt 16. The delimitation of the sucked region is indicated by angle symbols.
The advantage of the segmented sucking of the screening drum 14 also consists in that only a small air volume is necessary to be able to securely transfer the card webs at the transfer sites even at high transport speeds when the fiber take-off means 6a, 6b are laterally sealed. On the underside, the permeable conveyor belt 16 may comprise a suction box 18 at the transfer site 17 between the screening drum 14 and the conveyor belt 16, which suction box sucks the conveyor belt at the transfer site and in a predetermined region behind the transfer site. Alternatively, the underside of the conveyor belt may be provided with air guide blades 22 between the transfer site between the screening drum and the conveyor belt up to a site of transfer 20 to a succeeding machine, said guide blades providing for a secure adhesion of the card webs on the conveyor belt 16 as a consequence of the deflection of an airflow below the conveyor belt.
By a suitable pivoting means, the stuffing rollers 6a, 6b can be brought out of or into engagement.
Finally,
This permits the production of a high-performance intermediate card with a high mass per unit area of the resulting card web at a high production speed and with a short and compact construction.
In the embodiments of FIGS. 2 to 7, the screening drum 14 may also be sucked completely instead of in segments. It goes without saying that the conveyor belt 16 may also comprise air guide blades 22 at the underside between the point of separation from the screening drum 14 to the site of transfer 20 to the succeeding machine in the embodiments of FIGS. 2 to 7.
In all embodiments, it may be provided that the conveying means with the conveyor belt 16 is adapted to be pivoted about the rotational axis of the screening drum 14 so that the height of the site of transfer 20 to a succeeding machine is adjustable.
Between the take-off rollers 12a, 12b, 12c, 12d of all embodiments, air guiding means 13 such as tubes as shown in
The tangling roller 3c rotates in the same direction as the main cylinder 4 and in opposite direction to the rotational direction of two doffer rollers 8a, 8b being in engagement with the tangling roller 3c. Thus, the card web transferred from the main cylinder 4 to the tangling roller 3c is shared out between two doffer rollers 8a, 8b and transferred from there via take-off rollers 12a, 12b or stuffing rollers in combination with take-off rollers 12a, 12b onto the conveying surface 15 of the screening drum 14 and the conveying belt 16, respectively.
In the embodiment of
It goes without saying that the lower fiber take-off means may also be configured as illustrated in the other embodiments.
The diameter of the main cylinder amounts to approximately 1.200 to 1.800 mm, preferably 1.500 mm, the diameter of the tangling rollers being between 400 and 700 mm, preferably 550 mm.
Although the invention has been described and illustrated with reference to specific illustrative embodiments thereof, it is not intended that the invention be limited to those illustrative embodiments. Those skilled in the art will recognize that variations and modifications can be made without departing from the true scope of the invention as defined by the claims that follow. It is therefore intended to include within the invention all such variations and modifications as fall within the scope of the appended claims and equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 03 017 145.8 | Jul 2003 | EP | regional |
