Winding – tensioning – or guiding – Convolute winding of material – With cutting – perforating – or notching
Reexamination Certificate
2001-02-21
2002-11-19
Nguyen, John Q. (Department: 3653)
Winding, tensioning, or guiding
Convolute winding of material
With cutting, perforating, or notching
C225S004000, C225S093000
Reexamination Certificate
active
06481663
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. §119 of German Patent Application No. 100 07 833.8, filed on Feb. 21, 2000, the disclosure of which is expressly incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a process for severing a material web, and particularly severing the material web after the material web is wound onto a winding reel. The invention also relates to a reeling device for rolling a material web into a winding reel using at least one roll which is in contact with the winding reel and a severing device.
2. Discussion of Background Information
Paper webs are typically produced more or less continuously. They must be wound into rolls so that they can be handled later by a consumer. Such rolls, e.g., winding reels, have widths in the range of 0.3 to 3.8 m and diameters in the range of 0.8 to 2.5 m. As a result, they have a limited capacity in regards to storing the wound web. Thus, it is necessary from time to time to cut the material web after the winding reel has reached the desired final diameter. Moreover, the cutting of the web necessarily requires that an end of the cut paper web created thereby be fixed onto the winding reel to prevent its unwinding. Further, the other cut end of the paper web, i.e, a new beginning end, must then be fixed to a new roll core so that the new roll can be wound in a similar manner.
For this purpose, it is known to create a perforation line in the paper web, i.e., so as to weaken the web, before an actual or real separation point is reached. The winding reel is then rolled further and continues to pull the paper web onto itself until the perforation line reaches the desired separation point. Then, the paper web is held while the winding reel is removed from its winding position. This movement causes the paper web to tear along the perforation line, i.e., the web experiences tension and/or stretching until it is caused to tear along at its weakest point which happens to be the perforation line.
This process has essentially been proven. However, the process can only be used on webs having up to a certain basis weight of about 100 to 130 g/m
2
. Beyond that, webs cannot be severed with the aid of perforations with the necessary degree of reliability. Another disadvantage is that creating the perforations is relatively labor-intensive and thus expensive.
SUMMARY OF THE INVENTION
The invention therefore provides a device and method for the severing of a material web in a simple fashion largely independent of its basis weight.
The invention also provides for a device and a process which introduces an explosive and/or an explosive device (throughout the application explosive and explosive device are used interchangeably) between the material web and the winding reel and thereafter expanding the explosive device.
The explosive device may be rolled in between the winding reel and the outermost material web layer. The invention takes advantage of a design such that when the explosive device expands, there is essentially no space available for expanding the explosive device. As a result, the expansion of the explosive device causes the area of the web adjacent the explosive device to be destroyed at its “weakest” point. This area is the outermost layer of the material web. The material web is therefore ripped by the expansion of the explosive device, i.e., causing the web to tear. This finally results in a complete tearing through, i.e., a severing of the material web.
Preferably, the explosive device is introduced through a nip between a winding reel and a roll that is in contact with the winding reel, such that the material web is located in between. The explosive device is then expanded in an area behind the nip. This design also provides for the winding reel to squeeze the incoming material web between itself and the roll. Thus, when the explosive device expands, the space necessary for the expansion can be enlarged only by providing more material web. This design also fixes the material web. This has two advantages. On the one hand, the precision of the severing process is increased and, on the other hand, the position at which the separation occurs is better defined.
Advantageously, a reusable explosive device is used. This eliminates the exchange process after each separation process.
Preferably, the explosive device is a hose which is positioned laterally to the material web and is expanded by being inflated. The risk of damaging the winding reel in lower layers of the material web is comparatively low with such an inflatable hose. When the hose is inflated, the web is caused to rip at the point where it is the outermost material web layer of the winding reel. This is because this is the weakest point of the web. This design produces no remarkable observable negative effects on the winding reel or the web layers underneath the outermost layer.
The inflation preferably occurs abruptly. However, the inflation or the expansion may also occur slowly. This is because the paper web has only limited elasticity. As a result, as soon as the elasticity limit is reached, the web tears. However, the separation process may improve the faster the inflation occurs. This is because a separation of the material web occurs always when the expansion speed exceeds the maximal stretching speed of the material web. With an abrupt inflation speed, even material webs that are stretchable to a certain extent can be separated. In particular, in stronger materials, e.g., paper or cardboard with a basis weight of more than 120 g/m
2
, abrupt inflation has been performed successfully.
Preferably, the explosive device is moved away from the winding reel after the separation of the material web. In this way, more than merely the material web is separated, i.e., the beginning of the material web and the end of the material web may also be spatially separated from one another so that subsequent processing is facilitated.
The invention also provides for a winding device in which the severing device has an explosive device which can be rolled and/or placed between the material web and the winding reel so that it can be expanded there.
As explained above, the explosive device is expandable so that it can tear through the uppermost layer of the material web on the winding reel. This design takes advantage of the uppermost layer being the weakest point adjacent the area of the explosive device. Thus, it is possible to reliably sever even thicker material webs utilizing this design. Astonishingly, the resulting tear edge can be relatively “clean” using this design. Moreover, while the tear cannot properly be characterized as a straight tear line, nevertheless, it is not truly lacerated either.
Preferably, the explosive device is embodied as a hose that can be filled with air. Such a hose has the advantage that it forms a reusable explosive. In most production facilities, compressed air is available, so that only relatively few additionally mechanisms are needed for implementing the severing process per se.
Preferably, the explosive device is positioned on holding arms which can be tensed and/or moved by rotating the winding reel. The explosive device is positioned between the uppermost layer of the material web and the circumference of the winding reel during a rotational movement of the winding reel. Moreover, the invention may provide that during this movement, the holding arms are stretched so that the explosive device may be automatically retracted in the direction of the tension after the separation of the material web. The explosive device can be utilized at the same time to lift the beginning of the severed material web off the circumference of the winding reel. For example, this may be advantageous when an adhesive is applied to the material web before the material web is severed. Such a design means that it is then no longer necessary to pay so much attention to the separation line running outside of the sticky area. Thus, even if
Nguyen John Q.
Voith Paper Patent GmbH
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