Paper making and fiber liberation – Processes and products – Lead strip forming and/or guiding
Reexamination Certificate
2001-12-06
2002-12-17
Fortuna, Jose (Department: 1731)
Paper making and fiber liberation
Processes and products
Lead strip forming and/or guiding
C162S194000, C162S363000, C162S289000, C162S306000, C162S202000, C162S207000, C162S367000, C222S091000, C222S095000, C222S097000, C222S003000, C222S014000
Reexamination Certificate
active
06494992
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus for transporting a web of a flexible material between a first and a second position. In particular, and in a preferred embodiment, the invention provides an apparatus, known as a “vacuum conveyor”, for transporting a web, preferably a lead strip (or “tail”) of a paper web, e.g. from the dryer of a paper-making machine to the first nip of a calender of the machine or to a winding machine or between any other sections of a paper-making or paper-finishing (e.g. coating) machine.
2. Discussion of Background Information
vacuum conveyor is known from DE 26 36 887 which is similar to U.S. Pat. No. 4,022,366. Conveyors of this kind have proven successful in operation. In some applications, however, the lead strip must be deviated (in a known manner) out of the area of the web width into the area of a rope system which is outside the web width, for threading the lead strip through the following machine- section. For this purpose, the conveyor is arranged in an oblique position so that its downstream end is positioned in the area of the rope system outside the web width. A problem is that immediately after the transfer of the beginning of the lead strip into the rope system, the following main part of the lead strip shall travel again in its area inside the web width. Therefore, only the beginning of the lead strip must positively cling to the conveyor's belt. Immediately thereafter the lead strip should have only a loose contact to the conveyor. For that purpose one tries to rapidly decrease the degree of vacuum applied to the conveyor. But that does not always work in a reliable manner, in particle with the high operating speed of modem paper machines.
U.S. Pat. No. 4,692,215 discloses a vacuum conveyor cooperating with a rope system which again is positioned outside the web width. The vacuum conveyor is adjustable around a vertical axis which is arranged at the upstream pulley of the conveyor, so that the tail can be directed into the rope nip.
However, this document does not disclose any details how to control the adjustment or movement of the conveyor around the vertical axis. Such a control should be very precise because the transfer of the beginning of the tail into the rope nip must go on with the normal machine speed (up to about 2000 m/min), i.e., within a period of about 1 second or less. Moreover, U.S. Pat. No. 4,692,215 does not disclose any details how to support the vacuum conveyor with respect to the axis.
Therefore, the invention is based an the problem of further developing the known vacuum conveyor in such a way that the transfer of a lead strip into a following machine section is improved, in particular at high operating speeds.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, the belt conveyor can be pivoted—immediately after it has transferred the beginning of a leading strip into a rope system—from an oblique position into a straight, forward position, whereby it moves the lead strip into the area of the web width, so that, the conveyor now reliably transfers the main part of the lead strip—within the area of the web width—into the following machine section. In summary, the transfer of the lead strip from the preceding to the following machine section will be significantly improved, even at high operating speeds.
According to a second aspect of the invention, a vacuum conveyor is supported by a connecting structure which connects the conveyor with a rotatable support. The rotatable support includes a rotatable bearing housing which is fixed to the connecting structure, with at least one bearing being arranged within the bearing housing and being supported by a stationary central stub or by a stationary central section of the vacuum line. This design is very compact and very easy to integrate into any type of paper machine. This is due to the fact that the rotatable support includes a base plate, e.g., only one, for connecting the rotatable support to a machine frame. It is therefore a universal pivot which is applicable not only with the vacuum conveyor designed according to the first aspect, but also with various other vacuum conveyors. The pivot axis may be arranged, e.g., vertical but outside the web width in order to remove the conveyor out of the machine. In a different embodiment, the pivot axis may be arranged parallel to the pulley's axes in order to vary the working direction of the conveyor.
According to a third aspect of the invention, the vacuum conveyor is again connected to a rotatable support. The connecting structure is now formed as a vacuum channel. Therefore, it has two functions, namely to support the vacuum conveyor as well as to connect it to the vacuum source. This novel design is space-saving and the manufacturing costs are low.
The present invention is directed to an apparatus transferring at least a portion of a running web from a first section of a web making machine to a second section of the web making machine arranged downstream from the first section, relative to a web run direction, the second section including a portion adapted to receive a full width of the running web and a rope section located outside of the full width receiving portion. The apparatus includes a belt conveyor which includes at least two pulleys, in which at least one is a driven pulley, an air-pervious endless conveyor belt tensioned over the at least two pulleys to form a conveying run and a return run, and a device for creating a negative pressure at an inner surface of the conveying run. The at least one driven pulley being adapted to drive the endless conveyor belt over the at least two pulleys while the negative pressure propagates through the conveying run. The belt conveyor also includes an upstream and a downstream end and the belt conveyor is pivotable around a pivot axis located in a region of the upstream end. The apparatus is pivotable to move the portion of the running web between the rope section and the portion is adapted to receive a full width of the running web. The apparatus also includes a control system for moving the downstream end into an area of the web width when a beginning of the at least a portion of the web has entered the rope section.
According to a feature of the instant invention, a rotatable support, which is rotatable around the pivot axis and a connecting structure, may be adapted to support the apparatus. The connecting structure can couple the conveyor apparatus to the support. The rotatable support may be connected to a stationary structure by a motor for pivoting the apparatus. Further, the rotatable support can include a rotatable bearing housing which is fixed to the connecting structure, and at least one bearing may be arranged within the bearing housing and is supported by a stationary central stub.
In accordance with another feature of the present invention, the at least a portion of the running web includes a threading tail, and the running web includes a paper web.
According to still another feature of the invention, the pivot axis can be at least approximately vertical to a plane of a belt run direction.
The invention is also directed to an apparatus for transferring at least a portion of a running web including a belt conveyor that includes at least two pulleys, in which at least one is a driven pulley, an air-pervious endless conveyor belt tensioned over the at least two pulleys to form a loop, and a device for creating a negative pressure within the loop. The negative pressure is sufficient to draw the at least a portion of the running web onto the endless conveyor belt. The at least one driven pulley is adapted to drive the endless conveyor belt over the at least two pulleys, such that the negative pressure propagates through the conveyor belt. The apparatus also includes a connecting structure and a rotatable support which rotates around a pivot axis are provided, and the connecting structure couples the belt conveyor to rotatable support. The rotatable support includes a rotatable bear
Broom Allan
Drefs Wolfgang
Kutak-Petrik George
Mohrsen Leif
Fortuna Jose
Greenblum & Bernstein P.L.C.
Halpern Mark
Voith Sulzer Papiertechnik Patent GmbH
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