Winding – tensioning – or guiding – Convolute winding of material – With cutting – perforating – or notching
Reexamination Certificate
2000-03-23
2004-06-15
Walsh, Donald P. (Department: 3653)
Winding, tensioning, or guiding
Convolute winding of material
With cutting, perforating, or notching
Reexamination Certificate
active
06749146
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for threading a material web, e.g., a paper or cardboard web, onto a reel, such as onto an empty or partially wound reel, and a winding machine for threading a material web, e.g., a paper or cardboard web, onto a reel, such as onto an empty or partially wound reel.
2. Discussion of Background Information
Threading of a material web onto a reel is necessary at the beginning of a new winding process with a new, not yet wound reel (“empty reel”) or for continuing an already begun winding process after an unintentional or deliberate tearing of the web with a partially wound reel.
It is generally known for the leader strip (e.g., the edge strip of the material web), which comes from a machine for producing or refining a material web and which is guided over a part of the circumference of the support drum, to be threaded immediately onto the reel that forms a nip with the support drum. Only then is the leader strip widened out to the fall material web width. However, the immediate threading of the leader strip onto the reel produces a so-called “winding carrot” with an uneven distribution of the web tension at least in the winding core. Consequently, there is the disadvantage that when the material web is unwound again, the part of the material web that was initially wound on should be discarded as waste. It can also occur, for example, after a stoppage of the production or refining machines, that the material web does not initially have the desired quality and/or production features. In this instance, it is undesirable to wind on an unmarketable part of the material web, instead it should be immediately discarded as waste.
In order to prevent the formation of a “winding carrot” and in order to thread the material web onto the reel only after fulfillment of the desired quality and/or production features, as is also generally known, the leader strip is guided over a part of the circumference of the support drum preceding the reel and is supplied to a waste receptacle (“pulper”). Various waste receptacles are known from a number of published documents for example, from commonly owned European Patent No. EP 0 664 267 B1, from the commonly owned unpublished German Patent Application No. DE 197 44 505.5, and from the special edition of “Wochenblatt fur Papierfabrikation” [Paper Manufacturing Weekly] 123, 1995, No. 4, p. 5. After the leader strip has widened out by being continuously conveyed into the waste receptacle, the incoming material web, which is now fill width, is cut and only then is it threaded onto the reel.
The problem that arises in a process of this kind is that the leader strip or the material web has the tendency to thread itself onto the reel in an undesirable way before being cut (“self-threading”). The tendency of the leader strip or the material web to self thread is influenced by various factors, for example, the nip geometry, the surface form, or the percentage of open areas, the reference hardness, the nip force, and the paper properties. In addition, this problem occurs to a greater extent at high web speeds.
Therefore, attempts have already been made to solve this problem, e.g., as disclosed in the European Patent EP 0 658 504 B1, by forming the support drum preceding the reel as a suction drum. In this regard, a vacuum is produced in the drum, which acts on the material web via corresponding openings in the drum and holds the material web against the drum. A self-threading of the material web onto the reel can in fact be largely prevented. In this way, the vacuum in the support drum impedes the removal of the web in order to convey it into the waste receptacle.
Furthermore, the commonly owned unpublished German Patent Application DE 198 48 816.5 proposes a winding machine for winding a material web onto a reel, in which the material web, supplied by an inlet roll, is guided in conjunction with a perforated support belt over a support drum that can be supplied with suction and a nip is formed between the support drum and the reel. After the support drum, the support belt is guided over an outlet roll, which is disposed in the vicinity of a waste pulper. The leader end of the material web or the entire material web is discarded into the pulper before being subsequently threaded onto the reel. Furthermore, the support drum, which is provided with a perforated jacket and/or with circumference grooves, is externally supplied with suction in the part of its circumference that is not wound around by the perforated support belt and the material web. While this device can also prevent a self-threading of the material web onto the reel, the perforated support belt is subject to wear and must consequently be replaced at certain time intervals. Also, the provision of suction to the support drum, which is expensive to manufacture with its perforated jacket and/or circumference grooves, involves increased operating costs.
Furthermore, reference is also made to the commonly owned unpublished German Patent Application DE 198 48 806.8 with regard to the prior art. This patent application discloses a process for threading a material web onto a reel in which the beginning of the material web to be threaded is wound around a drum preceding the reel and, before being threaded onto the reel, is supplied to a preparation station, such as a waste pulper. In this connection, before being threaded onto the reel, the material web is kept away from the reel via blower air. A device for carrying out the process is also disclosed, which has a blower bar disposed lateral to the web travel direction, having at least one outlet opening for the blower air, a device for conveying blower air to the blower bar and a control device for controlling the introduction of blower air. While this process and this device can also prevent a self-threading of the material web onto the reel to a great extent, the demand for blower air involves increased investment costs and high ongoing operating costs for the disclosed device.
SUMMARY OF THE INVENTION
The present invention provides a process of the type generally discussed above in which the leader strip or the material web is initially conveyed into the waste receptacle in a reliable and controlled manner and in which self-threading of the leader strip or the material web onto the reel, independent of its current position, is substantially prevented. Moreover, the process does not impede the removal of the web from the support drum preceding the reel. The present invention also provides a suitable device for carrying out the process.
The process of the instant invention provides for threading a material web, e.g., a paper or cardboard web, onto a reel, such as an empty or partially wound reel. In particular, the process includes conveying the leader strip over a part of the circumference of the support drum and is then conveying the leader strip through an effective region of a guide device in a direction of a waste receptacle. The leader strip is then widened out to a desired width of the material web. Then, the reel is placed against the support drum, forming a nip between the support drum and the reel. Finally, the material web is cut and the winding of the material web onto the reel to form a wound roll begins.
The above-described process for threading a material web onto a reel, in particular an empty or partially wound reel, can be repeated with each threading of the material web.
A first additional embodiment of the invention provides that, before the leader strip is conveyed to the support drum, the reel is positioned such that a distance of at least approximately 1 mm is provided or maintained between the support drum and the reel. As a result, the leader strip or the material web can be effectively prevented from threading itself onto the reel.
Another embodiment of the invention provides for the effective region to be a contactless region, for example, that includes at least one air flow or at least one water jet. This results in the advanta
Madrzak Zygmunt
Wohlfahrt Matthias
Greenblum & Bernstein P.L.C.
Rodriguez Joseph
Voith Sulzer Papiertechnik Patent GmbH
Walsh Donald P.
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