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Title:
METHOD AND APPARATUS FOR THE SYNCHRONIZATION OF CUTTING ELEMENTS IN A CROSS-CUTTER FOR A WEB-LIKE MATERIAL
Document Type and Number:
WIPO Patent Application WO/2000/013862
Kind Code:
A1
Abstract:
The invention relates to a method and an apparatus for the synchronization of cutting elements (6, 7) in a cross-cutter for a web-like material (8), wherein the web (8) to be cut is fed between rolls (1, 2) provided with the cutting elements (6, 7). The rolls (1, 2) are functionally connected by means of at least one belt-like synchronization element (5) linking the rolls and exterior of the web run (8). The invention relates also to a continuous-action cross-cutter assembly for a web-like material (8), such as a web of pulp or the like, as well as to a continuous-action sheet cutting unit for a pulp drying machine.

Inventors:
Karhu, Martti (Niveräkatu 2 Karhula, FIN-48770, FI)
Application Number:
PCT/FI1999/000680
Publication Date:
March 16, 2000
Filing Date:
August 17, 1999
Export Citation:
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Assignee:
METSO PAPER, INC. (Fabianinkatu 9 A Helsinki, FIN-00130, FI)
Karhu, Martti (Niveräkatu 2 Karhula, FIN-48770, FI)
International Classes:
B26D1/62; B26D5/00; (IPC1-7): B26D5/00; B26D1/36; B26D1/40
Attorney, Agent or Firm:
LEITZINGER OY (Ruoholahdenkatu 8 Helsinki, FIN-00180, FI)
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Claims:
Claims
1. A method for the synchronization of cutting elements (6,7) in a cross cutter for a weblike material (8), wherein the web (8) to be cut is guided between rolls (1,2) provided with the cutting elements (6,7) to a cutting line at which the cutting elements (6,7) cut the weblike material as the rolls are rotating, characterized in that the rotation of the rolls (1,2) are synchronized relative to each other by connecting the rolls functionally by means of at least one beltlike synchronization element (5) external of the web run (8), at least one of said rolls (1,2) being provided with a drive.
2. A method as set forth in claim 1, characterized in that the beltlike syn chronization element (5) is driven by a separate drive wheel (4).
3. A method as set forth in claim 1 or 2, characterized in that the synchro nization element (5) is a twosided cogged belt (9).
4. A method as set forth in any of the preceding claims, characterized in that the tightness of the synchronization element (5) can be adjusted.
5. A method as set forth in any of the preceding claims, characterized in that the cutting elements (6,7) cut the weblike material by penetration.
6. An apparatus for the synchronization of cutting elements (6,7) in a crosscutter for a weblike material (8), comprising a pair of rolls (1,2) between which the weblike material (8) is fed to a cutting line, at which the cutting elements (6,7) cut the weblike material as the rolls are rotating, characterized in that the rolls (1,2), at least one of which is provided with a drive, have at least one end thereof or a section of the roll periphery exter nal of the web run, provided with a coupling ring for a beltlike synchroni zation element (5) functionally linking the rolls.
7. An apparatus as set forth in claim 6, characterized in that the apparatus is provided with a separate drive wheel (4), which is linked with the rolls (1, 2) by means of the beltlike synchronization element (5).
8. An apparatus as set forth in claim 6 or 7, characterized in that the cou pling ring comprises a toothed wheel or the like and the synchronization element (5) comprises a twosided cogged belt (9).
9. An apparatus as set forth in any of the preceding claims, characterized in that it is further provided with a jockey pulley (3), around which the syn chronization element (5) partially extends.
10. A continuousaction crosscutter assembly for a weblike material (8), such as a web of pulp or the like, said assembly comprising two parallel rolls (1,2) forming between each other a cutting line for the web (8) and which rolls (1,2) are adapted to rotate in such a way that each roll's cutting elements (6,7) cut the weblike material as the rolls are rotating, charac terized in that the rolls (1,2), at least one of which is provided with a drive, have at least one end thereof or a section of the roll periphery external of the web run, provided with a coupling ring for a beltlike synchronization element (5) functionally linking the rolls.
11. An assembly as set forth in claim 10, characterized in that the assem bly is provided with a separate drive wheel (4), which is linked with the rolls (1,2) by means of the beltlike synchronization element (5).
12. An assembly as set forth in claim 10 or 11, characterized in that the coupling ring comprises a toothed wheel or the like and the synchroniza tion element (5) comprises a twosided cogged belt (9).
13. An assembly as set forth in any of the preceding claims, characterized in that it is further provided with a jockey pulley (3), around which the syn chronization element (5) partially extends.
14. A continuousaction sheet cutting unit for a pulp drying machine, com prising at least a slitter mechanism for a pulp web (8) for slitting the same with a plural ity of crosswise adjusted slitter devices into lengthwise separate webs, a crosscutter assembly (1,2) for cutting the separate webs into sheets, an overlapping mechanism for sheets for overlapping the sheets in order to reduce the speed of a pulp web, as well as a bale table or the like for stacking the sheets into bales thereon, and possibly an additional cutter for cutting the baled sheets to a smaller size, characterized in that the crosscutter assembly comprises two parallel rolls, at least one or both of said rolls (1,2) being provided with a drive, and which forming therebetween a cutting line for the pulp web (8), and said rolls (1,2) being adapted to rotate in such a way that each roll's cut ting elements (6,7) cut the weblike material as the rolls are rotating, and the rolls (1,2) have at least one end thereof or a section of the roll periph ery external of the web run, provided with a coupling ring for a beltlike synchronization element (5) functionally linking the rolls.
Description:
Method and apparatus for the synchronization of cutting elements in a cross-cutter for a web-like material The present invention relates to a method and an apparatus for the syn- chronization of cutting elements in a cross-cutter for a web-like material, wherein the web to be cut is guided between rolls provided with the cutting elements to a cutting point at which the cutting elements cut a web-like material as the rolls are rotating.

One apparatus for cutting a web-like material, such as paper, board, and pulp, comprises so-called twin rotary cutters, wherein the web to be cut is guided through a cutting point constituted by two rolls, the circumferential surface of said rolls being provided with cutting knives. As the rolls are rotating, the knives must coincide with each other at the cutting point.

As a consequence, the knife rolls must rotate at an extreme precision and also in a synchronized fashion, such that the cutting knife and its backing roll always and continually coincide with each other, even at high running speeds. In current solutions, the synchronization is generally effected by means of a gearing, its gearwheels rotating in an oil bath. In addition, the equipment is provided with a mechanism for eliminating the clearance for providing a precise synchronization. An object of the invention is to provide a reliable synchronizer which is simpler than the prior art mechanisms.

In order to achieve this objective, it is suggested, according to a method of the invention, that the rolls be synchronized relative to each other in terms of the motion thereof by connecting the rolls functionally by means of at least one belt-like synchronization element external of the web run, at least one of said rolls being provided with a drive.

The method of the invention can be carried out by using a separate drive wheel, the belt-like synchronizer element of the invention being coupled therewith in addition to the rolls.

The belt-like synchronizer element used in the invention comprises prefer- ably a two-sided cogged belt, which is functionally linked with the rolls and possibly with the drive wheel.

In a preferred embodiment, the belt can be regulated in terms of its tight- ness by using a jockey pulley, the synchronizer element extending therearound in addition to the rolls and optionally the drive wheel.

The invention relates also to an apparatus for implementing the above method, said apparatus being characterized in that the rolls, at least one of which is provided with a drive, have at least one end thereof, or a section of the roll periphery external of the web run, provided with a coupling ring for a belt-like synchronization element functionally linking the rolls. In the apparatus of the invention, one or both of the rolls are driven. Alternatively, it is possible to employ a separate drive wheel, the belt-like synchroniza- tion element extending therearound in addition to the rolls.

For a simpler construction, the synchronization element comprises a two- sided cogged belt, which enables a gearless drive and a cooperation be- tween the rolls, the drive wheel, and optionally a jockey pulley.

In addition, the present invention relates to a continuous-action cross- cutter assembly for a web-like material, such as a web of pulp or the like, said assembly comprising two parallel rolls, forming therebetween a cutting line for the web and which rolls are adapted to rotate in such a way that each roll's cutting elements coincide with each other at the cutting line as the rolls are rotating. This assembly of the invention is characterized in that the rolls, at least one of which is provided with a drive, have at least one end thereof, or a section of the roll periphery external of the web run, provided with a coupling ring for a belt-like synchronization element func- tionally linking the rolls.

Furthermore, the invention relates to a continuous-action sheet cutting unit for a pulp drying machine, comprising at least

-a slitter mechanism for a pulp web for slitting the same with a plurality of crosswise adjusted slitter devices into lengthwise separate webs, -a cross-cutter assembly for cutting the separate webs into sheets, -an overlapping mechanism for sheets for overlapping the sheets in order to reduce the speed of a pulp web, as well as -a bale table or the like for stacking the sheets into bales thereon, and -possibly an additional cutter for cutting the baled sheets to a smaller size, said unit employing the above-described continuous-action cross-cutter assembly for a web-like material.

The method and apparatus of the invention, as well as the applications thereof, are simple in terms of operation and construction, have a clearance-free drive, nor does the apparatus require separate processes for eliminating the clearance. By virtue of a simple construction, all that is needed are lightweighted protective elements and complicated and bulky gear transmissions can be completely omitted.

The invention is particularly applicable in cutting methods or the like mak- ing use of penetrating, wherein the knife clearance has a minor impor- tance.

The expression"cutting knife"used in this specification and claims refers to a knife or other element for severing a web by cutting, penetrating, or by another such method.

The invention will now be described in more detail from the schematic configuration depicted in the accompanying figure.

The figure shows one embodiment of the invention in an end view.

A pulp web 8, whose running direction is shown by an arrow, is fed through two large rolls 1,2, said rolls being parallel to each other, the circumfer- ential surfaces thereof being provided with two cutting knives 6 in the top

roll 1 and two backing knives 7 in the bottom roll, which are positioned respectively on the outer periphery of the roll. As the rolls are rotating, the knife 6 and its backing knife 7 coincide with each other at a cutting line formed by the knives for cutting the web 8 crosswise. It is obvious that the knives 6,7 must have a precise synchronization, such that the knife 6 and its backing knife 7 always hit the right spot at the right time. This synchro- nization will be all the more important, the higher the machine running speeds will become.

The end surfaces of the rolls 1 and 2 are provided with rings, beneath the roll 2 is a small vertically movable roll 3, as well as alongside the rolls 1 and 2 is yet a further roll, i. e. a drive roll 4. All these rolls are linked by a belt-like synchronization element 5, which in the depicted case comprises a cogged belt 9 as shown in the detail of the drawing.

The synchronization element 5 extends around about half of the circumfer- ence of the drive roll and continues therefrom to the bottom roll 2 and runs around a ring-shaped element in its end surface and continues therefrom directly downwards to the jockey pulley 3. Thus, the circuit is complete and the endless synchronization element 5, preferably a two-sided cogged belt 9, connects all relevant rolls, the bottom roll 2 functioning at the same time as a reversing roll, wherein one side of the cogged belt is in contact with the end ring.

The end rings of the rolls 1 and 2, whose diameter in the depicted case is substantially smaller than the overall roll diameter, the jockey pulley 3 as well as the drive wheel 4 are respectively provided with a toothed rim which meshes with the toothing of the cogged belt 9.

In the illustrated case, the cogged belt 9 couples with the rolls 1 and 2 by way of toothed wheels (toothing not shown in the drawing) present at the ends thereof. It is naturally also possible that the toothed wheel is mounted on the roll mantle or belt, in which case it is necessary to make sure that the toothed wheel is not in contact with the web run itself.

In the illustrated case, the apparatus is provided with a separate drive wheel 4. In an alternative solution, it can be omitted, one or both of the rolls 1,2 being driven.

The drawing shows the machine in an end view, the synchronization ele- ment of the invention being mounted on one end of the apparatus. It is also possible that the other end of the apparatus, opposite to the end shown in the figure, be provided with a similar type of synchronization element.

The illustrated method and mechanical solution can be implemented in any cross-cutting assembly, in addition to which it can be fitted subsequently in currently existing equipment.