EP0995560A2 - Machine for transversely cutting webs - Google Patents

Abstract

A cross cutter for web materials, in particular paper, has a knife shaft (13) which is composed of a light metal knife roller (19) and a steel shaft end 14. This consists of a bearing (12) and drive (17) receiving pin and a flange (16) which is connected to the knife roller by means of a non-positive and positive connection. For the non-positive connection, screw bolts (35) are inserted into bushings (33), which are screwed and glued into corresponding recesses in the cutter block. In addition, a dowel connection is provided.

Description

APPLICATION AREA AND PRIOR ART

The invention relates to a cross cutter for web materials, especially paper.

From DE-U-89 00 516 is a cross cutter for corrugated cardboard has become known, which has a knife roller, which has the shape a tube made of carbon fiber composite material. On this A knife holder is attached to the tube by means of screws. The Storage and drive takes place via existing metal Bearing stubs that are incorporated into the tube.

It is also from DE-A-195 45 003 a knife shaft become known, the outer shell of a metal hollow profile, especially made of aluminum, which has a Inner shell made of fiber composite material runs around. There is the knife carrier is formed in the outer shell. For storage shaft journals are attached in a torsionally and flexurally rigid manner.

To be different with cross cutters without changing the knife shaft To be able to cut formats, it is e.g. from the DE-C-36 08 111 known, the knife shafts over non-uniform speed gearbox or preferably via controllable electric motors with large acceleration and braking torques non-uniform to drive. The speed of the knife shafts becomes Cutting a format that is longer than that by the Scope of knife waves certain synchronous format, in the course one turn braked and at the time of the cut accelerated again to the web speed. It is also possible by periodic acceleration to a peripheral speed shorter above the web speed Formats to cut as the sync format. The basic parameters of required cutting lengths and the possible acceleration and Braking values determine the synchronous cut length, i.e. the Knife shaft diameter.

TASK AND SOLUTION

The object of the invention is a cross cutter for web materials to create a wide range of variations the synchronous cut length and all requirements with regard to the structure, in particular the attachment of the knife shaft, the possibility of applying the enormous torques and sufficient torsional and flexural rigidity for the Knife shaft allowed.

This object is achieved by claim 1 solved.

The knife roller made of light metal is very similar shaft cross-section to be designed favorably the smaller Modulus of elasticity compared to steel with regard to torsion and Bending stiffness. At the same time, it enables compared to a lightweight construction using carbon composite materials (CFK) a direct attachment of the Knives on the knife roller, which would not be possible with CFRP.

On the other hand, with the conventional solution of a knife shaft made of steel due to the high moment of inertia not possible due to the required deviations from the synchronous cutting length of accelerations and Bring delays. This applies in particular to the preferred cross cutters with one Web speed up to 400 m / min.

For the knife shaft according to the invention, large mean Synchronous cut lengths are no problem. But it can also be used for smaller synchronous cut lengths than usual, for example of 500 mm can be used. In the usual the required web widths of approx. 2,000 mm would be a knife shaft a circle diameter with only one knife on the circumference of only about 160 mm, which is because of the demands Flexural rigidity in the previous arrangements and materials would not be possible. Therefore, after the knife shaft Invention selected a shape with two knives on the circumference the knife shaft on the double Brings diameter that with conventional knife shafts made of steel or the like due to the high moment of inertia the sufficient acceleration values are not possible.

This is possible with the invention, especially since the knife carriers also directly into the knife roller made of light metal can be incorporated so that the torsion and Bending stiffness important outer diameters only a little smaller must be as the knife flight circle. With CFRP knife rollers, the appear to be suitable for these extreme conditions Knife beds made of steel would have to, for reasons of stability be provided by the large knife flight circle cause excessive inertia and attach it to the knife roller is problematic and weakens it.

The peak values of the drive torque and the corresponding one Braking torque is around 5,000 Nm. They are too Bending moments due to cutting force. These powers require a firm and secure fit of the shaft bearings and the synchronous wheels transmitting the drive. This is with a shaft end structure made from the material of the knife roller, So light metal, especially aluminum alloy, not too to reach. In the invention, therefore, the shaft ends are off a material with high strength, especially steel, manufactured. The difficult problem to fix between the light metal knife roller and the steel shaft ends requires special measures in the invention are formed by the flange that practically over the entire circumference of the knife roller is sufficient and for a non-positive and / or positive connection. Especially preference is given to both non-positive and positive Connection, especially for both types of connection are designed so that they alone drive torque could transmit. Although it is preferred, training of the shaft end with a flange at both ends of the knife shaft could be provided with one-sided arrangement of the drive only the drive-side shaft end must be connected in such a way because in addition to the bending moments there is also the drive torque is to be transferred.

The connection between the flange and the essentially cylindrical knife roller can be frictionally engaged respectively. To do this, circular cylindrical recesses, which runs longitudinally over the knife roller Can continue drilling, bushings with a particularly well fitting low-play screw thread used and possibly also in it still be glued. Fastening screws can be inserted into these sockets be screwed into the face of the flange press the knife roller. For an optimal adhesion and to secure against loosening of the bushings these can be slightly opposite the face of the cutter block are recessed so that the flange is only on the end face the knife roller and not on those of the bushings. By the choice of a fine thread between bushes and knife roller it is self-locking under force. The transfer of the Significant screw forces are therefore very large on the less solid material of the knife roller. This would be with a direct screwing of the fastening screws hardly possible.

Preferably, the knife roller can have several, also over the Scope distributed, have recesses for dowel bolts that fitted in and in the flange and if necessary by locking screws are secured. They form a form-fitting Connection.

The construction of the shaft ends with molded flange enables so a very large transfer of forces. In the frictional transmission must have very high contact forces Act. They can be applied to a very large area be so that, despite high screw forces, no overuse of the light metal material is to be feared. These frictional forces act due to the fact that it is practical the entire circumference (except for the knife carrier recesses) for Frictional power transmission is available while out sections of the end face made of another material, so the area of the bushings, opposite the aluminum face is set back and the frictional force transmission is not can disturb.

In particular through the combination of frictional engagement and fitting bolts, i.e. thanks to a non-positive and positive connection Connection, is a reliable power transmission in this particularly critical case of a connection between two parts of a knife shaft possible. The non-positive Transmission ensures that the transmission is completely free of play is otherwise she could work her way out. The form fit through the dowel pin ensures security at one Release of the frictional connection and relieves it at the same time, without affecting him.

It is particularly advantageous that the various connecting elements on the knife roller, i.e. the socket recesses just like the dowel pin recesses and the continuous Central bore, which preferably receives a centering pin, can be arranged so that they have a profile an extremely rigid and torsionally rigid design for the knife roller result. For example, if the four Bushing recesses evenly distributed over the circumference be arranged between two of them a knife carrier recess lies and the recesses for the fitting bolts in contrast, offset by approx. 90 ° and close to the circumference, then is not only due to the relatively large circumferential distance Form and frictional transmission cheap, but it arises a wheel-spoke-like structure of the knife roller with a continuous load-bearing cross-section in the outside area and one inner cross-spoke structure that is also oriented that it runs balanced by the individual Recesses distributed relatively evenly over the circumference are. One of the spokes lies approximately in the connection two knife carriers, so that the strut on the Knife acting bending forces can be absorbed.

These and other features go beyond the claims also from the description and the drawings, wherein the individual features individually or separately several in the form of sub-combinations in one embodiment of the invention and in other fields be and advantageous as well as protective designs can represent, for which protection is claimed here. The division of the application into individual sections as well Subheadings limit those made under them Statements are not generally applicable.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1

einen Teillängsschnitt durch eine Messerwelle,

Fig. 2

eine teilgeschnittene Seitenansicht desselben Abschnittes, jedoch in um 90° versetzter Lage,

Fig. 3 u. 4

Schnitte nach den Linien III und IV in Fig. 1 und

Fig. 5

eine Ansicht aus Richtung des Pfeiles V in Fig. 1 gesehen.

An embodiment of the invention is shown in the drawings and is explained in more detail below. The drawings show:

Fig. 1

a partial longitudinal section through a knife shaft,

Fig. 2

a partially sectioned side view of the same section, but in a position offset by 90 °,

Fig. 3 u. 4th

Cuts along lines III and IV in Fig. 1 and

Fig. 5

a view seen from the direction of arrow V in Fig. 1.

DETAILED DESCRIPTION OF THE EMBODIMENT

In a cross cutter 11, of which only part of the housing is indicated, and which is a so-called Folio cross cutter is in bearings 12 is a knife shaft 13 stored. It cuts in cooperation with you accordingly, i.e. trained essentially the same Counter knife from one path, from several, from different Upcoming paper roll bearings exist, relatively large Sheets of paper that are subsequently, e.g. in giants or stacks of paper collected on pallets.

At the shaft end 14 shown in the drawings 1 and 2 the Knife shaft 13, which consists of a multi-stepped pin 15 and a flange 16 integral therewith intervenes Drive 17, to which a synchronous gear 47 belongs, the is rotatably attached to the shaft journal. This gear meshes with a corresponding synchronous gearwheel with the shown cutter shaft 13 cooperating cutter shaft. Usually there are synchronous wheels at both ends of a knife shaft intended. The drive from the drive motors can either directly on the shaft journal 15 or via the synchronous gear respectively. Usually with such large cross-cutters Drives as directly flanged, controlled electric motors provided that are able to yourself and the knife shaft in fractions of a revolution to that of the web speed corresponding speed to accelerate and off this to a lower speed or to a standstill slow down.

The cutting area 48 of the knife shaft extends to that pin-side end of the flange 16. Up to there forms the Outer periphery 18 of the flange the immediate continuation of the Surface of a knife roller 19, which most of the Occupies the cutting area. The knife roller consists of a circular cylindrical section made of an aluminum alloy (see Fig. 3), in the outer circumference opposite to each other Recesses 20 in the manner of approximately longitudinal Grooves for knife holder 21 for attaching the lighter Knife 22 clamped to the axis is provided is. The clamping takes place via a clamping wedge 23, which Knife in the area of its thickening away from the cutting edge Tight foot. The clamping wedge 23 is by screws 53 into the trapezoidal ones narrowing in cross section Recesses 20 drawn into it. On the knife 22 opposite side is the recess 20 (knife groove) lined with a steel strip 54, which for a uniform Distribution of the contact pressure without plastic deformation worries.

The important setting for a precise cut Knife takes place over a multitude of arranged side by side and approximately tangentially directed adjusting screws 24, in corresponding threaded holes 25 in the knife roller 19 are screwed in. The knife carrier recesses 20 and the knife 22 also extend over the outer circumference of the flange 16 away, so that this is an active part of the knife shaft forms. The knife attachments, e.g. the clamping wedges 23, additionally act like pass wedges that are described later Support flange / knife roller connection.

Fig. 3 also shows that the made of solid material Knife roller has a plurality of longitudinal bores all run parallel to the axis of rotation 26 of the cutter shaft 13. Four holes are provided, the socket recesses 27 form. They have a relatively large cross-section, e.g. between 25 and 40% of the knife roller diameter and so are arranged that their axes 28 on the corners of an imaginary Squares. This is arranged so that the knife holder are approximately in the extension of the webs 29, which are form between the socket recesses 27. 3 are the recesses 20 somewhat laterally in between each two socket recesses 27 forming solid material gusset 49 shown what results from the oblique course of the knife carrier recess 20 results. On average, she is in the middle of a gusset arranged. 90 ° offset from the gusset 49 are dowel pin recesses 30 is provided, which is relatively close to the circumference 18 of the Knife roller are provided. They are an extension of the Crosspieces 29 between socket recesses 27, which are at right angles the previously mentioned webs.

Since the bushing recesses are also relatively close to the circumference 18 reach is an area in the middle of the cross section formed, which occupies a central recess 31 which is coaxial extends to the axis of rotation 26.

The cross section of the knife roller 19 thus has its solid material sections that have remained between the recesses the shape of a central central recess 31 wheel arranged around it with hub, four spokes (webs 29) and a peripheral, largely closed edge area 32 like a wheel tire. The socket recesses are located here 27 regularly distributed around the axis of rotation 26 and compared to smaller dowel pin recesses on the one hand and the recesses 20 for the knife are on the other hand each in the gaps in between, so that there is largely self-balanced and especially with regard to the Main stresses (torsion and bending) stable, on the other hand but in terms of inertia and weight, which in the bend comes in, gives almost ideal structure.

a) In die Buchsenausnehmungen 27 sind Stahlbuchsen 33 eingeschraubt. Dazu ist im Inneren der Buchsenausnehmungen ein Feingewinde 34 vorgesehen. Die Gewindepassung wird dabei so vorgesehen, daß sie spielarm eingreift. Außerdem ist die axiale Gewindetiefe so bemessen, daß die Buchsen bis ans Gewindeinnere, d.h. "auf Block" eingeschraubt werden. Zusätzlich wird das Gewinde durch Einkleben mittels eines entsprechenden Metallklebers gesichert. Im Zusammenwirken dieser Merkmale mit dem starken Axialzug, der danach durch jeweils zwei in die Buchsen eingeschraubte Schraubbolzen 35 ausgeübt wird, sind die Buchsen praktisch unlösbar in den Buchsenausnehmungen gesichert. Bei der Einbringung der Buchsen erweist sich auch die Materialpaarung als vorteilhaft. Die einzelnen Gewindegänge sind dadurch gleichmäßig belastet, daß der Werkstoff der Messerwalze (Leichtmetallegierung) einen etwa dreifach niedrigeren Elastizitätsmodul als die aus Stahl gefertigte Buchse 33 besitzt. Dementsprechend legen sich die Gewindegänge der Messerwalze bei Belastung gleichmäßig an das Außengewinde aus Stahl an und übertragen die aufgebrachte Vorspannkraft über die gesamte Gewindelänge zu nahezu gleichen Lastanteilen. Dies ist also viel günstiger als bei einer Gewindepaarung aus gleichen Materialien, bei der der Hauptlastanteil nur über die ersten Gewindegänge übertragen wird.Die Buchsen haben einen Mantel 36 und, im dem Flansch zugekehrten Bereich, einen dicken Boden 37. In diesem Boden werden nach der Einbringung der Buchsenausnehmungen passend zu entsprechenden Schraubenlöchern 38 im Flansch je Buchse zwei Gewindebohrungen eingebracht, in die kräftige Schraubbolzen 35 eingeschraubt werden, deren Köpfe in entsprechenden Ansenkungen im Flansch liegen. Die Bolzen liegen nicht zentrisch zu den Buchsen, mehr zum Außenumfang hin versetzt. Aus Fig. 5 ist zu erkennen, daß die insgesamt acht in die vier Buchsenausnehmungen eingeschraubten Schrauben auf einem Schraubenkreis liegen, der einen Durchmesser von etwa zwei Drittel bis drei Viertel des Durchmessers Umfanges des Flansches 16 hat.Beim Einbringen der Buchsen wird darauf geachtet, daß ihr Boden 37 gegenüber der Verbindungsebene 39 zwischen Flansch 16 und Messerwalze 19 geringfügig zurückversetzt ist, so daß in dem entsprechenden Bereich 40 kein unmittelbarer Kontakt zum Flansch 16 besteht. Die durch die Schraubbolzen 35 ausgeübten Zugkräfte pressen dementsprechend den Flansch 16 nur auf die Stirnfläche der Messerwalze 19, so daß diese sich ideal an die entsprechende Stirnfläche des aus härterem Material bestehenden Flansches 16 anpassen kann.

b) Der Flansch 16 hat in seiner Mitte einen vorstehenden Zentrierzapfen 41, der in eine entsprechende Ausdrehung im Bereich der Mittelausnehmung 31 eingreift und für eine genaue Zentrierung bei der Montage sorgt.

c ) Obwohl die durch die beschriebene, von den Schraubbolzen erzeugte Anpreßkraft entstehenden Reibkräfte bereits ausreichen, um insbesondere die hohen zu übertragenden Drehmomente einschließlich der vom Schnitt herrührenden Stoßbelastungen aufzunehmen, wird vorzugsweise zusätzlich eine formschlüssige Verbindung vorgenommen, in dem relativ dicke Paßbolzen 42 eingebracht sind. Sie greifen in einen entsprechend genau bearbeiteten Bereich der Paßbolzenausnehmungen 30 ein und durchqueren auch den Flansch gänzlich (Fig. 2). Sie sind durch eine zusätzliche Maden-Sicherungsschraube 43 gesichert. Auch die Paßbolzen sind so ausgelegt, daß sie allein auch die auftretenden Kräfte übertragen könnten. Sie werden im Normalfall nicht belastet, weil durch die kraftschlüssige Verbindung keine Bewegungstendenzen zwischen Messerwalze und Flansch auftreten. Daher können sie auch nicht durch die bei Abweichung der Synchron-Schnittlänge auftretende starke Wechselbelastung (zweimal Beschleunigung und zweimal Verzögerung während jeder Umdrehung) ausgeschlagen werden.

The connection between the shaft end 14 and the knife roller 19 has three main features in the illustrated embodiment:

a) Steel bushings 33 are screwed into the bush recesses 27. For this purpose, a fine thread 34 is provided in the interior of the socket recesses. The thread fit is provided so that it engages with little play. In addition, the axial thread depth is dimensioned so that the bushes are screwed into the inside of the thread, ie "on block". In addition, the thread is secured by gluing in with an appropriate metal adhesive. In interaction of these features with the strong axial pull, which is then exerted by two screw bolts 35 screwed into the sockets, the sockets are secured in the socket recesses practically indissolubly. When inserting the bushes, the material pairing also proves to be advantageous. The individual threads are evenly loaded because the material of the knife roller (light metal alloy) has an approximately three times lower elastic modulus than the bushing 33 made of steel. Accordingly, the threads of the cutter block lie evenly against the external thread made of steel when they are loaded and transmit the applied preload force over the entire thread length at almost the same load. So this is much cheaper than with a thread pairing of the same materials, in which the main load portion is only transmitted via the first threads. The bushings have a jacket 36 and, in the area facing the flange, a thick bottom 37 Inserting the bushing recesses corresponding to the corresponding screw holes 38 in the flange, two threaded holes are made in the bushing, into which strong screw bolts 35 are screwed, the heads of which lie in corresponding countersinks in the flange. The bolts are not centered on the bushings, but rather offset towards the outer circumference. From Fig. 5 it can be seen that the total of eight screws screwed into the four socket recesses lie on a screw circle which has a diameter of about two thirds to three quarters of the diameter of the flange 16. When inserting the sockets, care is taken to ensure that its bottom 37 is slightly set back relative to the connecting plane 39 between the flange 16 and knife roller 19, so that there is no direct contact with the flange 16 in the corresponding region 40. The tensile forces exerted by the screw bolts 35 accordingly press the flange 16 only onto the end face of the knife roller 19, so that it can adapt ideally to the corresponding end face of the flange 16 made of harder material.

b) The flange 16 has in its center a protruding centering pin 41 which engages in a corresponding recess in the region of the central recess 31 and ensures precise centering during assembly.

c) Although the frictional forces generated by the contact pressure generated by the screw bolts are sufficient to absorb in particular the high torques to be transmitted, including the shock loads resulting from the cut, a positive connection is preferably additionally made in which relatively thick dowel bolts 42 are introduced. They engage in a correspondingly precisely machined area of the dowel pin recesses 30 and also traverse the flange entirely (FIG. 2). You are secured by an additional maggot locking screw 43. The dowel bolts are also designed so that they alone could transmit the forces that occur. They are normally not loaded because there is no tendency to move between the cutter block and the flange due to the non-positive connection. Therefore, they cannot be knocked out by the strong alternating load that occurs when the synchronous cutting length deviates (twice acceleration and twice deceleration during each revolution).

The invention is the most important part in a cutter shaft forming a cross cutter a principle redundancy reached. As a material for the knife roller can instead the preferred aluminum alloy every other technically available light metal can be used. Because of the special Connection method between the light metal body of the Knife roller and the shaft end 14 with steel pin 15 and Flange 16 ensures that in particular the aluminum material nowhere too high becomes. So it cannot be plastic or impermissibly large elastic deformations occur.

Claims (10)

Sheeters for web materials, especially paper, with at least one knife shaft (13) which is a knife roller (19) axially over a major part of a Cutting area (48) and at least on the circumference (18) a knife held in a knife holder (21) (22), and has the knife shaft ends, in the Storage area (12) and / or drive (17) for the Knife shaft (13) attacks, the shaft ends (14) connected to the separately manufactured knife roller (19) are characterized in that at least one Shaft end (14) made of a material with high strength, in particular steel, and at its Knife roller (19) facing a flange (16) has, which is essentially to the extent of Knife roller (19) is sufficient and with a light metal existing knife roller non-positively and / or positively connected is. Cross cutter according to claim 1, characterized in that the knife shaft (13) on the circumference of two knives (22) having. Cross cutter according to claim 1 or 2, characterized in that the knife roller (19) several, preferably four, distributed over the scope, in particular over the entire length of the knife roller (19) continuous and preferably has circular cylindrical recesses (27), into the steel bushings (33), if applicable Screwing and / or gluing are used, in which the Fixing screws pressing the flange onto the cutter block (35) are screwed in, preferably the Screw forces are such that the between the flange (16) and the end face resting thereon (39) of the knife roller (19) occurring friction forces larger are than the workers, especially acceleration forces as a result of the rotation of the knife shaft changing peripheral speeds. Cross cutter according to one of the preceding claims, characterized in that the knife roller (19) has a plurality of preferably two, distributed over the circumference, especially over the entire length of the knife roller continuous, and preferably circular cylindrical recesses (30), into which steel, if applicable Dowel bolts (42) are used, which are also by appropriate Pass the fitting holes of the flange (16) through, preferably their non-destructive and deformation-free forces to be absorbed are greater than the workforce, especially acceleration forces as a result of over the knife shaft rotation of changing peripheral speeds. Cross cutter according to claim 3 or 4, characterized in that the sockets (33) are not immediate Have support on the flange (16). Cross cutter according to one of the preceding claims, characterized in that the knife carrier (21) directly formed in the material of the knife roller (19) is and in particular also on the flanges (16) Shaft ends (14) are sufficient. Cross cutter according to one of claims 3 to 6, characterized characterized in that the knife roller (19) from a in essentially cylindrical light metal body, on its circumference two knife carriers opposite each other (21), preferably molded directly into this are provided, in particular by the Knife roller (19) four in diameter, angular essentially evenly distributed Socket recesses (27) protrude. Cross cutter according to one of claims 4 to 7, characterized characterized in that the knife carrier (21) in the area a recess (20) of the knife roller (19) in each case between two of the socket recesses (27) and / or in circumferential area between two of the socket recesses (27) two dowel pin recesses (30) continuously are arranged, where appropriate in the circumferential direction Knife roller (19) each have a bushing recess (27) and a knife carrier (21) or a dowel recess alternate. Cross cutter according to one of the preceding claims, characterized in that the flange (16) a Centering pin (41) having a central Middle recess (31) engages in the knife roller (19), preferably the central recess (31) continuous circular cylindrical bore is. Cross cutter according to one of the preceding claims, characterized in that the at least one knife carrier (21) a recess (20) in the form of a Cross-section of trapezoidal groove in the light alloy knife roller (19), on the side wall or at least excellent adjusting screws (24) a clamping wedge (23) presses the knife, the opposite Side wall with a steel strip (54) is lined between the clamping wedge (23) and the material of the knife roller (19).

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