EP0453851B1 - Cutting device for document shredder - Google Patents

Cutting device for document shredder Download PDF

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Publication number
EP0453851B1
EP0453851B1 EP19910105529 EP91105529A EP0453851B1 EP 0453851 B1 EP0453851 B1 EP 0453851B1 EP 19910105529 EP19910105529 EP 19910105529 EP 91105529 A EP91105529 A EP 91105529A EP 0453851 B1 EP0453851 B1 EP 0453851B1
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EP
European Patent Office
Prior art keywords
cutting
knife
shafts
cutting device
disks
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EP19910105529
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German (de)
French (fr)
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EP0453851A1 (en
Inventor
Willi Strohmeyer
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Geha Werke GmbH
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Geha Werke GmbH
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B02CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02CCRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C18/00Disintegrating by knives or other cutting or tearing members which chop material into fragments
    • B02C18/0007Disintegrating by knives or other cutting or tearing members which chop material into fragments specially adapted for disintegrating documents
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B02CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02CCRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C18/00Disintegrating by knives or other cutting or tearing members which chop material into fragments
    • B02C18/06Disintegrating by knives or other cutting or tearing members which chop material into fragments with rotating knives
    • B02C18/16Details
    • B02C18/24Drives

Definitions

  • the invention relates to a cutting device for a document shredder with two rotating knife shafts arranged parallel to one another and driven by toothed wheels, each of which has a multiplicity of axially lined up, intermeshing knife disks, which act in pairs in the axial direction on their cutting flanks, i.e. be kept in cut contact.
  • GB-A-2064365 shows that spacer bushes can be arranged between the cutter disks of the cutter shafts.
  • the required cut contact of the knife disks is effected by an adjusting screw.
  • the described possible use of helical gears is also not used to generate an axially directed force component that could be used to make the cut contact between the cutter disks.
  • the invention is based on the object of avoiding the disadvantages mentioned and of adapting the axial forces effective on the knife shafts to the respective load.
  • the fact that the gears are fixed on the knife shafts in the axial direction and provided with helical gears means that, depending on the load on the cutting unit, i. builds up a load-dependent force component that is effective in the axial direction on the knife shafts from the amount of the document being fed.
  • This force component acting in the axial direction can be selected by the angle of the helical toothing of the gear wheels so that it maintains the cutting contact between the cutting flanks of the knife disks under all operating conditions.
  • the effect of the helical toothing of the gearwheels depending on the design of the housing of the cutting unit, often already results from the elasticities in the housing of the cutting unit and possibly also on the cutter discs. With the action of the axial force acting on the cutter shafts, these elasticities often already require a sufficiently large axial displacement of the cutter disks, which compensates for the evasive movement thereof due to the load during the cutting process.
  • a further advantageous effect results from the fact that, in the event that the cutting unit is stuck due to an overload, the direction of rotation is reversed when reversing, that an axial force component is built up on the helical gears of the gear wheels, which has the tendency to relieve the cutting flanks of the cutter disks and to move the cutter disks away from one another.
  • This effect encourages the cutting unit to run freely when reversing.
  • this effect also results without additional components having to be arranged or additional constructive measures causing costs having to be taken.
  • At least one of the knife shafts is supported with axial play.
  • Such an axial play ensures, regardless of the elasticity in the housing of the cutting unit, that the axial force component generated by the helical gears of the gear wheels becomes fully effective on the cutting flanks of the cutter disks.
  • running backwards i.e. when reversing the cutting unit to a clear separation of the cutting edges of the cutter discs from each other.
  • a clear gap is formed between the knife disks in accordance with the size of the axial play of the knife shafts, which significantly promotes the free running of the cutting mechanism.
  • cutter disks are formed as stamped parts and are braced against one another by means of spacers on the shafts of the cutter shafts.
  • Such a knife shaft is inexpensive to manufacture and, with the correct dimensioning of the parts, in particular also in a cutting unit with the features according to the invention, has a sufficiently high stability.
  • 1 denotes a cutting mechanism which has two rotating knife shafts 3 arranged parallel to one another and driven via gear wheels 2.
  • the gears 2 are provided with interlocking helical gears 4 and are arranged on the knife shafts 3 in a rotationally fixed and fixed manner in the axial direction.
  • the knife shafts 3 are formed by knife disks 5, which are lined up on shafts 6 and braced against one another by means of spacers 7, i.e. are attached.
  • the spacers 7 determine the distance between the individual cutter disks 5 from one another.
  • One of the knife shafts 3 is additionally provided with a drive gear 8, via which the cutting mechanism is driven by means of a drive motor, not shown in the drawing.
  • the knife shafts 3 are supported on both sides on shaft journals 9 in bearings 10 which are arranged in a housing 11 of the cutting mechanism 1. Both knife shafts 3 have an axial play between a shoulder 12 on the shaft journal 9 and one bearing 10 each.
  • the helical gears 4 of the gears 2 fixed on the knife shafts 3 in the axial direction give rise to axially directed forces on the knife shafts 3 while the cutting mechanism 1 is running, which push the knife disks 5 of both knife shafts 3 against one another or when Reverse movement of the cutting unit 1 move the knife disks 5 away from each other.
  • the play between the lugs 12 and the bearings 10 of the knife shafts 3 enables a slight axial movement of the knife shafts 3, which ensure the described effect in the exemplary embodiment shown.
  • an axial force component arises when the cutting unit 1 is running, the size of which depends on the size of the total transmitted to the gearwheels 2 Force.
  • the size of the force component acting in the axial direction is therefore dependent on the load on the cutting unit 1, that is to say on the quantity of the documents to be fed.
  • the axial force component thus counteracts the cutting forces acting on the cutter shafts 3, which have the tendency to push the cutter disks 5 away from each other, and, with the correct dimensioning of the angle of the helical gears 4 of the gear wheels 2, ensures that the cutting mechanism 1 functions optimally under all operating conditions, ie one flawless cutting process on the cutting edges 13 safely.
  • the axial force components act counter to one another and move the cutter disks 5 of the cutter shafts 3 away from one another.
  • the gap that forms between the knife disks 5 favors the free running of the cutting unit 1 after blocking due to an overload.
  • the described effect according to the invention results depending on the design of the cutting unit 1 under certain conditions, and also when the knife shafts are mounted without play. If the housing 11 of the cutting unit or the knife shafts 3 have an elasticity of a certain size, depending on the load on the cutting unit 1, there is a load-dependent increase in the pressure on the cutting flanks 13 of the knife disks 5. The pressure therefore acts in particular in the case of lighter cutters 1 counteracts the deformation occurring due to the load and also ensures perfect functioning under all operating conditions. It is also the case here that the cutting flanks 13 of the knife disks 5 are relieved during reversing, which favors the free running of a blocked cutting unit.

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  • Engineering & Computer Science (AREA)
  • Food Science & Technology (AREA)
  • Crushing And Pulverization Processes (AREA)

Description

Die Erfindung betrifft ein Schneidwerk für einen Schriftgutvernichter mit zwei parallel zueinander angeordneten, über Zahnräder angetriebenen, rotierenden Messerwellen, die jeweils eine Vielzahl von axial aneinandergereihten, ineinandergreifenden Messerscheiben aufweisen, die von einer in Axialrichtung wirksamen Kraft an ihren Schneidflanken paarweise auf Anschlag, d.h. in Schnittkontakt gehalten werden.The invention relates to a cutting device for a document shredder with two rotating knife shafts arranged parallel to one another and driven by toothed wheels, each of which has a multiplicity of axially lined up, intermeshing knife disks, which act in pairs in the axial direction on their cutting flanks, i.e. be kept in cut contact.

Bei den Schneidwerken der genannten Gattung ist es wichtig, daß auch unter höherer Belastung der Messerwellen stets ein guter Schnittkontakt zwischen den Schneidflanken der Messerscheiben erhalten bleibt. Sofern sich die Schneidflanken beispielsweise auf Grund von Elastizitäten im Gehäuse des Schriftgutvernichters voneinander entfernen, kommt es eher zu einem Reißen als zu einem sauberen Schneiden der Schriftstücke. Dieses führt dazu, daß eine erhöhte Schneidleistung benötigt wird und daß sich vermehrt Schneidpartikel, Papierfasern und Schneidstaub in den Zwischenräumen zwischen den Messerscheiben ansammeln, die ein einwandfreies Auswerfen der Papierstreifen behindern, so daß die Neigung des Schneidwerkes, auf Grund einer Überlastung zu blockieren, erhöht wird.With the cutting units of the type mentioned, it is important that good cutting contact is always maintained between the cutting flanks of the cutting discs, even under higher loads on the cutting shafts. If the cutting flanks move away from one another, for example due to elasticities in the housing of the document shredder, the documents are more likely to be torn than to be cut cleanly. This means that an increased cutting performance is required and that more cutting particles, paper fibers and cutting dust accumulate in the spaces between the cutter disks, which impede the proper ejection of the paper strips, so that the tendency of the cutting mechanism to block due to overloading increases becomes.

Durch das DE-GM 88 13 569 ist es bereits bekannt geworden, an wenigstens einer der beiden Messerwellen eines Schneidwerkes der genannten Gattung eine in Axialrichtung wirksame Feder anzuordnen. Diese Feder stellt sicher, daß die Schneidflanken der Messerscheiben unter allen Betriebsbedingungen miteinander in Kontakt bleiben, so daß ein sauberer Schnitt des Schriftgutes gewährleistet ist. Nachteilig ist es jedoch, daß die Federkraft auf die größte Belastung ausgelegt und daher recht groß sein muß. Dieses führt dazu, daß auch im Leerlauf bzw. bei geringer Belastung des Schneidwerkes relativ große Reibungskräfte wirksam sind und daß im Schneidwerk ein relativ großer Verschleiß auftritt. Außerdem stellt die Feder ein zusätzliches Bauteil dar und die Anordnung der Feder erfordert zusätzliche konstruktive Maßnahmen im Schneidwerk. Dieses führt insgesamt zu einer Verteuerung des Schneidwerkes.From DE-GM 88 13 569 it has already become known to arrange an axially effective spring on at least one of the two cutter shafts of a cutting unit of the type mentioned. This spring ensures that the cutting flanks of the knife disks remain in contact with one another under all operating conditions, so that a clean cut of the writing material is ensured. However, it is disadvantageous that the spring force is designed for the greatest load and must therefore be quite large. This means that even when idling or at low Load of the cutting unit are relatively large frictional forces effective and that a relatively large amount of wear occurs in the cutting unit. In addition, the spring is an additional component and the arrangement of the spring requires additional design measures in the cutting unit. Overall, this increases the cost of the cutting unit.

Durch die US-A-4157671 ist es auch bereits bekannt geworden, die Schneidwalzen eines Schneidwerkes von je einem Antriebsmotor über, mit einer Schrägverzahnung versehene Zahnräder anzutreiben. Hier soll jedoch offensichtlich mittels einer extrem kleinen Zähnezahl des Ritzels lediglich ein sehr großes Übersetzungsverhältnis ermöglicht werden. Das Ritzel muß, um den auftretenden Belastungen standhalten zu können, mit einer Evolventenverzahnung versehen sein. Die zur Erzielung des erforderlichen Schnittkontaktes an den Messerscheiben erforderliche axiale Kraft muß mittels einer Stellschraube eingestellt werden. Es ist hier nachteilig, daß die mittels der Stellschraube eingestellte axiale Anpressung der Messerscheiben stets der im Betrieb auftretenden größten Belastung des Schneidwerkes angepaßt sein muß. Dieses führt dazu, daß auch im Leerlauf bzw. auch bei geringer Belastung des Schneidwerkes relativ hohe, nachteilige Reibungskräfte zu überwinden sind. Außerdem verteuert die Anordnung einer Stellschraube das Schneidwerk und erfordert im übrigen bei der Montage bzw. bei der Wartung und Reparatur zusätzliche aufwendige Einstellarbeiten.From US-A-4157671 it has also become known to drive the cutting rollers of a cutting unit by one drive motor each via gearwheels provided with helical teeth. Here, however, obviously only a very large transmission ratio should be made possible by means of an extremely small number of teeth of the pinion. In order to be able to withstand the loads that occur, the pinion must be provided with involute teeth. The axial force required to achieve the required cut contact on the knife disks must be set using an adjusting screw. It is disadvantageous here that the axial pressure of the knife disks set by means of the adjusting screw must always be adapted to the greatest load on the cutting unit that occurs during operation. This leads to the fact that relatively high, disadvantageous frictional forces have to be overcome even when idling or even when the cutting unit is under low load. In addition, the arrangement of a set screw makes the cutting mechanism more expensive and, moreover, requires additional complex adjustment work during assembly or during maintenance and repair.

Der GB-A-2064365 ist zu entnehmen, daß zwischen den Messerscheiben der Messerwellen Distanzbuchsen angeordnet sein können. Auch hier wird jedoch der erforderliche Schnittkontakt der Messerscheiben durch eine Einstellschraube bewirkt. Der beschriebene mögliche Einsatz auch schräg verzahnter Zahnräder erfolgt auch hier nicht zur Erzeugung einer axial gerichteten Kraftkomponente, die zur Herstellung des Schnittkontaktes zwischen den Messerscheiben genutzt werden könnte.GB-A-2064365 shows that spacer bushes can be arranged between the cutter disks of the cutter shafts. Here too, however, the required cut contact of the knife disks is effected by an adjusting screw. The described possible use of helical gears is also not used to generate an axially directed force component that could be used to make the cut contact between the cutter disks.

Auch der in der World Patent Index, Assession Nr. 85-054895(09), Derwent Publ. Ltd. London, GB; & SU-A-1105305 (Lugovov) 30-07-1984 (D3), ist ein elektrischer Rasierapparat beschrieben, der ein Getriebe aufweist, in dem lastabhängige axiale Kräfte erzeugt und genutzt werden. Die schräg verzahnten Antriebsräder der beaufschlagten Wellen werden hier jedoch von einem gemeinsamen Ritzel angetrieben. Die Wellen haben folglich die gleiche Drehrichtung. Für einen Schriftgutvernichter mit gegenläufig angetriebenen Wellen ist das beschriebene Getriebe folglich nicht einsetzbar.Also in the World Patent Index, Assession No. 85-054895 (09), Derwent Publ. Ltd. London, GB; & SU-A-1105305 (Lugovov) 30-07-1984 (D3), an electric shaver is described which has a transmission in which load-dependent axial forces are generated and used. However, the helical gear wheels of the loaded shafts are driven by a common pinion. The waves therefore have the same direction of rotation. The gear described cannot therefore be used for a document shredder with counter-driven shafts.

Der Erfindung liegt die Aufgabe zugrunde, die genannten Nachteile zu vermeiden und eine Anpassung der an den Messerwellen wirksamen Axialkräfte an die jeweilige Belastung zu erreichen.The invention is based on the object of avoiding the disadvantages mentioned and of adapting the axial forces effective on the knife shafts to the respective load.

Diese Aufgabe wird erfindungsgemäß durch die Merkmale des Anspruchs 1 gelöst. Dadurch, daß die Zahnräder auf den Messerwellen in Axialrichtung fixiert und mit Schrägverzahnungen versehen sind, wird erreicht, daß sich in Abhängigkeit von der Belastung des Schneidwerkes, d.h. von der Menge des zugeführten Schriftgutes eine in Axialrichtung an den Messerwellen wirksame, lastabhängige Kraftkomponente aufbaut. Diese in Axialrichtung wirksame Kraftkomponente kann durch den Winkel der Schrägverzahnungen der Zahnräder so gewählt werden, daß sie den Schneidkontakt zwischen den Schneidflanken der Messerscheiben unter allen Betriebsbedingungen aufrechterhält. Die Wirkung der Schrägverzahnung der Zahnräder ergibt sich in Abhängigkeit von der Auslegung des Gehäuses des Schneidwerkes vielfach bereits auf Grund der Elastizitäten im Gehäuse des Schneidwerkes und gegebenenfalls auch an den Messerscheiben. Diese Elastizitäten bedingen bei Einwirkung der an den Messerwellen wirksamen Axialkraft häufig bereits eine ausreichend große axiale Verschiebung der Messerscheiben, die die Ausweichbewegung derselben auf Grund der Belastung während des Schneidvorganges ausgleicht.This object is achieved by the features of claim 1. The fact that the gears are fixed on the knife shafts in the axial direction and provided with helical gears means that, depending on the load on the cutting unit, i. builds up a load-dependent force component that is effective in the axial direction on the knife shafts from the amount of the document being fed. This force component acting in the axial direction can be selected by the angle of the helical toothing of the gear wheels so that it maintains the cutting contact between the cutting flanks of the knife disks under all operating conditions. The effect of the helical toothing of the gearwheels, depending on the design of the housing of the cutting unit, often already results from the elasticities in the housing of the cutting unit and possibly also on the cutter discs. With the action of the axial force acting on the cutter shafts, these elasticities often already require a sufficiently large axial displacement of the cutter disks, which compensates for the evasive movement thereof due to the load during the cutting process.

Ein weiterer vorteilhafter Effekt ergibt sich daraus, daß für den Fall, daß das Schneidwerk auf Grund einer Überlastung festgelaufen ist, die Drehrichtungsumkehr beim Reversieren bewirkt, daß an den Schrägverzahnungen der Zahnräder eine axiale Kraftkomponente aufgebaut wird, die die Tendenz hat, die Schneidflanken der Messerscheiben zu entlasten und die Messerscheiben voneinander wegzubewegen. Dieser Effekt begünstigt das Freilaufen des Schneidwerkes beim Reversieren. Im übrigen ergibt sich auch dieser Effekt, ohne daß zusätzliche Bauteile angeordnet bzw. zusätzliche kostenverursachende konstruktive Maßnahmen ergriffen werden müssen.A further advantageous effect results from the fact that, in the event that the cutting unit is stuck due to an overload, the direction of rotation is reversed when reversing, that an axial force component is built up on the helical gears of the gear wheels, which has the tendency to relieve the cutting flanks of the cutter disks and to move the cutter disks away from one another. This effect encourages the cutting unit to run freely when reversing. In addition, this effect also results without additional components having to be arranged or additional constructive measures causing costs having to be taken.

Vorteilhaft kann es sein, wenn wenigstens eine der Messerwellen mit axialem Spiel gelagert ist. Ein derartiges axiales Spiel stellt unabhängig von Elastizitäten im Gehäuse des Schneidwerkes sicher, daß die von den Schrägverzahnungen der Zahnräder erzeugte axiale Kraftkomponente an den Schneidflanken der Messerscheiben voll wirksam wird. Andererseits kommt es beim Rückwärtslauf, d.h. beim Reversieren des Schneidwerkes zu einer deutlichen Trennung der Schneidflanken der Messerscheiben voneinander. Es bildet sich zwischen den Messerscheiben entsprechend der Größe des axialen Spiels der Messerwellen ein deutlicher Spalt aus, der das Freilaufen des Schneidwerkes erheblich begünstigt.It can be advantageous if at least one of the knife shafts is supported with axial play. Such an axial play ensures, regardless of the elasticity in the housing of the cutting unit, that the axial force component generated by the helical gears of the gear wheels becomes fully effective on the cutting flanks of the cutter disks. On the other hand, when running backwards, i.e. when reversing the cutting unit to a clear separation of the cutting edges of the cutter discs from each other. A clear gap is formed between the knife disks in accordance with the size of the axial play of the knife shafts, which significantly promotes the free running of the cutting mechanism.

Vorteilhaft ist es weiterhin, wenn die Messerscheiben als Stanzteile ausgebildet und mittels Distanzbuchsen auf den Wellen der Messerwellen gegeneinander verspannt sind. Eine derartige Messerwelle ist kostengünstig herstellbar und weist bei richtiger Dimensionierung der Teile, insbesondere auch in einem Schneidwerk mit den erfindungsgemäßen Merkmalen eine ausreichend große Stabilität auf.It is also advantageous if the cutter disks are formed as stamped parts and are braced against one another by means of spacers on the shafts of the cutter shafts. Such a knife shaft is inexpensive to manufacture and, with the correct dimensioning of the parts, in particular also in a cutting unit with the features according to the invention, has a sufficiently high stability.

In der Zeichnung ist ein Ausführungsbeispiel eines erfindungsgemäßen Schneidwerkes im Längsschnitt dargestellt und wird im folgenden näher beschrieben.In the drawing, an embodiment of a cutting unit according to the invention is shown in longitudinal section and is described in more detail below.

In der Zeichnung ist mit 1 ein Schneidwerk bezeichnet, das zwei parallel zueinander angeordnete, über Zahnräder 2 angetriebene rotierende Messerwellen 3 aufweist. Die Zahnräder 2 sind mit ineinandergreifenden Schrägverzahnungen 4 versehen und auf den Messerwellen 3 drehfest und in Axialrichtung fixiert angeordnet.In the drawing, 1 denotes a cutting mechanism which has two rotating knife shafts 3 arranged parallel to one another and driven via gear wheels 2. The gears 2 are provided with interlocking helical gears 4 and are arranged on the knife shafts 3 in a rotationally fixed and fixed manner in the axial direction.

Die Messerwellen 3 sind von Messerscheiben 5 gebildet, die auf Wellen 6 aufgereiht und mittels Distanzbuchsen 7 gegeneinander verspannt, d.h. befestigt sind. Die Distanzbuchsen 7 bestimmen dabei den Abstand der einzelnen Messerscheiben 5 zueinander. Eine der Messerwellen 3 ist zusätzlich mit einem Antriebszahnrad 8 versehen, über das das Schneidwerk mittels eines in der Zeichnung nicht dargestellten Antriebsmotors angetrieben wird.The knife shafts 3 are formed by knife disks 5, which are lined up on shafts 6 and braced against one another by means of spacers 7, i.e. are attached. The spacers 7 determine the distance between the individual cutter disks 5 from one another. One of the knife shafts 3 is additionally provided with a drive gear 8, via which the cutting mechanism is driven by means of a drive motor, not shown in the drawing.

Die Messerwellen 3 sind auf Wellenzapfen 9 in Lagern 10, die in einem Gehäuse 11 des Schneidwerkes 1 angeordnet sind, beidseitig gelagert. Beide Messerwellen 3 weisen dabei ein axiales Spiel zwischen einem Ansatz 12 am Wellenzapfen 9 und jeweils einem Lager 10 auf.The knife shafts 3 are supported on both sides on shaft journals 9 in bearings 10 which are arranged in a housing 11 of the cutting mechanism 1. Both knife shafts 3 have an axial play between a shoulder 12 on the shaft journal 9 and one bearing 10 each.

Wie in der Zeichnung durch axial gerichtete Pfeile kenntlich gemacht, entstehen auf Grund der Schrägverzahnungen 4 der auf den Messerwellen 3 in Axialrichtung fixierten Zahnräder 2 bei laufendem Schneidwerk 1 an den Messerwellen 3 axial gerichtete Kräfte, die die Messerscheiben 5 beider Messerwellen 3 gegeneinanderschieben bzw. beim Rückwärtslauf des Schneidwerkes 1 die Messerscheiben 5 voneinander weg bewegen. Das Spiel zwischen den Ansätzen 12 und den Lagern 10 der Messerwellen 3 ermöglicht eine geringfügige Axialbewegung der Messerwellen 3, die in dem dargestellten Ausführungsbeispiel den beschriebenen Effekt sicherstellen.As indicated in the drawing by axially directed arrows, the helical gears 4 of the gears 2 fixed on the knife shafts 3 in the axial direction give rise to axially directed forces on the knife shafts 3 while the cutting mechanism 1 is running, which push the knife disks 5 of both knife shafts 3 against one another or when Reverse movement of the cutting unit 1 move the knife disks 5 away from each other. The play between the lugs 12 and the bearings 10 of the knife shafts 3 enables a slight axial movement of the knife shafts 3, which ensure the described effect in the exemplary embodiment shown.

An den Schrägverzahnungen 4 der Zahnräder 2 entsteht bei laufendem Schneidwerk 1 eine axiale Kraftkomponente, deren Größe abhängig ist von der Größe der an den Zahnrädern 2 insgesamt übertragenen Kraft. Die in Axialrichtung wirkende Kraftkomponente ist also in ihrer Größe abhängig von der Belastung des Schneidwerkes 1, d.h. abhängig von der Menge des zugeführten Schriftgutes. Je größer die Belastung des Schneidwerkes 1 ist, desto größer ist auch die in axialer Richtung wirksame Kraftkomponente, die die Messerscheiben 5 an ihren Schneidflanken 13 gegeneinander preßt. Die axiale Kraftkomponente wirkt also den an den Messerwellen 3 wirksamen Schneidkräften, die die Tendenz haben, die Messerscheiben 5 voneinander wegzudrücken, entgegen und stellt bei richtiger Dimensionierung des Winkels der Schrägverzahnungen 4 der Zahnräder 2 unter allen Betriebsbedingungen eine optimale Funktion des Schneidwerkes 1, d.h. einen einwandfreien Schneidvorgang an den Schneidflanken 13 sicher.On the helical gears 4 of the gearwheels 2, an axial force component arises when the cutting unit 1 is running, the size of which depends on the size of the total transmitted to the gearwheels 2 Force. The size of the force component acting in the axial direction is therefore dependent on the load on the cutting unit 1, that is to say on the quantity of the documents to be fed. The greater the load on the cutting mechanism 1, the greater is the force component acting in the axial direction, which presses the cutter disks 5 against one another on their cutting flanks 13. The axial force component thus counteracts the cutting forces acting on the cutter shafts 3, which have the tendency to push the cutter disks 5 away from each other, and, with the correct dimensioning of the angle of the helical gears 4 of the gear wheels 2, ensures that the cutting mechanism 1 functions optimally under all operating conditions, ie one flawless cutting process on the cutting edges 13 safely.

Beim Reversieren des Schneidwerkes 1 wirken die axialen Kraftkomponenten entgegengesetzt und bewegen die Messerscheiben 5 der Messerwellen 3 voneinander weg. Der sich bildende Spalt zwischen den Messerscheiben 5 begünstigt das Freilaufen des Schneidwerkes 1 nach dem Blockieren infolge einer Überlastung.When the cutting mechanism 1 is reversed, the axial force components act counter to one another and move the cutter disks 5 of the cutter shafts 3 away from one another. The gap that forms between the knife disks 5 favors the free running of the cutting unit 1 after blocking due to an overload.

Der beschriebene erfindungsgemäße Effekt ergibt sich in Abhängigkeit von der Auslegung des Schneidwerkes 1 unter bestimmten Voraussetzungen, und auch dann, wenn die Messerwellen ohne Spiel gelagert sind. Sofern das Gehäuse 11 des Schneidwerkes bzw. die Messerwellen 3 an sich eine Elastizität von einer gewissen Größe aufweisen, kommt es in Abhängigkeit von der Belastung des Schneidwerkes 1 zu einer lastabhängigen Verstärkung der Anpressung an den Schneidflanken 13 der Messerscheiben 5. Die Anpressung wirkt also insbesondere bei leichter gebauten Schneidwerken 1 der auf Grund der Belastung eintretenden Verformung entgegen und stellt auch hier eine einwandfreie Funktion unter allen Einsatzbedingungen sicher. Auch hier gilt, daß beim Reversieren die Schneidflanken 13 der Messerscheiben 5 entlastet werden, was ein Freilaufen eines blockierten Schneidwerkes begünstigt.The described effect according to the invention results depending on the design of the cutting unit 1 under certain conditions, and also when the knife shafts are mounted without play. If the housing 11 of the cutting unit or the knife shafts 3 have an elasticity of a certain size, depending on the load on the cutting unit 1, there is a load-dependent increase in the pressure on the cutting flanks 13 of the knife disks 5. The pressure therefore acts in particular in the case of lighter cutters 1 counteracts the deformation occurring due to the load and also ensures perfect functioning under all operating conditions. It is also the case here that the cutting flanks 13 of the knife disks 5 are relieved during reversing, which favors the free running of a blocked cutting unit.

Claims (3)

  1. A cutting device (1) for a document shredder, comprising two rotating knife rotors (3) arranged parallel to each other and driven by gearwheels (2) with helical gearing, the knife rotors (3) each being provided with a plurality of knife discs (5) which engage axially with each other and the cutting flanks (13) of which are held as pairs in cutting contact by a force acting in an axial direction and of variable magnitude, characterised in that helical gearwheels (2), fixed in an axial direction and engaging with each other, are arranged on both knife rotors (3) such that the force components, acting in an axial direction and building up on the gearwheels (2) as a function of the load on the cutting device (1), maintain the necessary cutting contact between the cutting flanks (13) of the knife discs (5) in dependence on the load.
  2. A cutting device (1) according to claim 1, characterised in that at least one of the knife rotors (3) is mounted with axial play.
  3. A cutting device according to claim 1, and where appropriate claim 2, characterised in that the knife discs (5) are in the form of pressings and are braced against each other through distance bushes (7) on the shafts (6) of the knife rotors (3).
EP19910105529 1990-04-21 1991-04-08 Cutting device for document shredder Expired - Lifetime EP0453851B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4012727 1990-04-21
DE19904012727 DE4012727A1 (en) 1990-04-21 1990-04-21 CUTTING DEVICE FOR A WRITER

Publications (2)

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EP0453851A1 EP0453851A1 (en) 1991-10-30
EP0453851B1 true EP0453851B1 (en) 1994-06-22

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EP19910105529 Expired - Lifetime EP0453851B1 (en) 1990-04-21 1991-04-08 Cutting device for document shredder

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EP (1) EP0453851B1 (en)
DE (2) DE4012727A1 (en)
DK (1) DK0453851T3 (en)
ES (1) ES2055483T3 (en)

Cited By (1)

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Publication number Priority date Publication date Assignee Title
CN102600944A (en) * 2011-03-07 2012-07-25 绿友机械集团股份有限公司 Cutter disc structure of small branch grinder

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Publication number Priority date Publication date Assignee Title
DE19746847A1 (en) * 1997-10-23 1999-04-29 Schleicher & Co Int Cutting mechanism for document shredder, especially with torsion cut
DE19757766A1 (en) * 1997-12-23 1999-06-24 Hermann Schwelling Device for delayed drive shutdown of document shredders
CN102941144B (en) * 2012-11-20 2015-04-08 东莞精锐电器五金有限公司 Single cutting type paper shredding cutter, paper shredding mechanism and paper shredding method
CN107583737B (en) * 2017-06-21 2019-05-28 浙江齐嘉消防科技有限公司 A kind of efficiently cutting equipment
CN112323922B (en) * 2020-10-14 2022-08-12 李海斌 Two-way anti-sticking dead garbage disposer

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FR1286449A (en) * 1961-04-18 1962-03-02 Fichtel & Sachs Ag Progressive torque transmission device by V-belt
US3286574A (en) * 1964-04-22 1966-11-22 Durand Auguste Paul Paper slitting apparatus
DE1810622A1 (en) * 1968-11-23 1970-06-11 Schleicher Co Feinwerktech Compact drive assembly for a paper disinte - grator
US4157671A (en) * 1976-03-11 1979-06-12 Albert Goldhammer Drive for cutting rollers of paper shredding or cutting apparatus
US4330092A (en) * 1979-12-07 1982-05-18 The Perkin-Elmer Corporation In-line shredder apparatus
DE8813569U1 (en) * 1988-10-28 1989-01-12 Wilhelm Dahle Büro-Technik GmbH & Co KG, 8630 Coburg Scraperless cutting unit for a document shredder

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102600944A (en) * 2011-03-07 2012-07-25 绿友机械集团股份有限公司 Cutter disc structure of small branch grinder

Also Published As

Publication number Publication date
EP0453851A1 (en) 1991-10-30
DK0453851T3 (en) 1994-08-15
ES2055483T3 (en) 1994-08-16
DE4012727A1 (en) 1991-10-24
DE4012727C2 (en) 1993-09-09
DE59101977D1 (en) 1994-07-28

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