EP0204266B1 - Tablet-compressing machine - Google Patents

Tablet-compressing machine Download PDF

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Publication number
EP0204266B1
EP0204266B1 EP86107315A EP86107315A EP0204266B1 EP 0204266 B1 EP0204266 B1 EP 0204266B1 EP 86107315 A EP86107315 A EP 86107315A EP 86107315 A EP86107315 A EP 86107315A EP 0204266 B1 EP0204266 B1 EP 0204266B1
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EP
European Patent Office
Prior art keywords
pressure rollers
tablet
matrices
preliminary
disk
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
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EP86107315A
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German (de)
French (fr)
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EP0204266A1 (en
Inventor
Jürgen Hinzpeter
Ingo Schmidt
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Fette GmbH
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Wilhelm Fette GmbH
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Publication of EP0204266A1 publication Critical patent/EP0204266A1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/02—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space
    • B30B11/08—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space co-operating with moulds carried by a turntable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/005—Control arrangements

Definitions

  • the invention relates to a rotary tablet machine for compressing
  • Powdery or granular pressed material which has a rotatable die plate and matrices distributed over the circumference as well as upper and lower punches arranged above and below the die plate, with which the pressed material can be pressed into tablets by means of adjustable pre-pressure and main pressure rollers, in which a main pressure roller is also used a servomotor controlled by a computer is provided, with which the distance between the main pressure rollers can be changed.
  • Such rotary tablet machines are used for the production of compacts from a wide variety of materials, i.e. not only for the manufacture of tablets from medicinal products intended for human consumption, but also for compacts, for example made of plastic or a metal powder or a ceramic mass.
  • the individual tablets are produced by compressing the powdery molding compound in a die of a rotating die between an upper punch and a lower punch.
  • the force for compressing the molding compound at the main printing station is generated in that the upper punch and the lower punch are passed between main pressure rollers, the distance between which can be changed by an actuator in order to be able to specify the size of the main pressing force.
  • the molding compound is pre-compressed at a pre-printing station using a pre-pressing force before the main printing station.
  • This pre-pressing force is usually considerably less than the main pressing force.
  • the pre-pressing force is 10 kN (Kilo Newton) and the main pressing force is 40 kN. (Exhibition "ACHEMA” Frankfurt am Main 1979; machine type Perfecta 1000).
  • the main pressing forces required to manufacture tablets are so high that they are close to the permissible load limit of the punches for eating. Due to malfunctions such as double fillings, the limit of the permissible load of a main press ram can be exceeded, causing the ram to compress or break. In order to counter this, it is known to provide overpressure safeguards that are preloaded hydraulically or with springs.
  • the object of the present invention is to provide a tabletting machine and a method for controlling its pressure rollers, which reduces the risk of stamp breaks occurring at the main pressing station.
  • a computer controls the servomotor for the distance between the main pressure rollers based on the measured pressing force of the pre-pressure rollers.
  • the pre-pressing force of each punch is thus measured and evaluated at the pre-printing station. Even if this pre-pressing force is considerably lower than the main pressing force at the main pressure station, its size allows a conclusion to be drawn about the size of the main pressing force to be expected. As a result, it can already be recognized from the size of the pre-pressing force whether the pressing force at the main printing station will exceed the permissible punch load.
  • a limit is set for the pre-pressing force, when exceeded by the maximum of the pre-pressing force, the press is stopped suddenly, so that the pre-pressed tablet in question does not reach the main pressure rollers with their associated stamps.
  • These are automatically moved apart by a certain size at the same time or after the die plate is shut down, so that the punches with the excessive pre-pressing force can be passed through in a computer-controlled manner without excessive main pressing force and without the risk of damage between the main pressure rollers which have moved apart.
  • the tabletting machine is then stopped again "in order to avoid expelling too many bad tablets, which would occur when the main pressure rollers were reset to the originally intended distance. Once this reset has been carried out, the tablets continue to be produced automatically.
  • the main pressure rollers are preferably mounted in supports whose spacing can be adjusted by the servomotor.
  • the servomotor is coupled in a gear-like manner to a length-adjustable rod which is connected to the carriers of the main pressure rollers, the main pressure rollers being able to be mounted in a parallelogram-type pressure frame.
  • the control of the servomotor for the main pressure rollers and the drive motor for the die plate is preferably carried out using a microprocessor which is connected to strain gauges, with which the pre-pressing forces of the pre-pressure rollers have it measured in a known manner.
  • the rotary tablet machine shown in the drawing has a die plate 1 rotating around the arrow 7, which is provided with dies 2, which are arranged evenly distributed over the circumference.
  • the matrices 2 are filled at a filling station 3 with material to be pressed, which is pre-pressed at a pre-printing station 4 using the pre-pressure rollers 11 and 12 (FIG. 2). These pre-pressure rollers 11 and 12 act on the upper punch 9 and lower punch 10 associated with each die for pre-pressing a tablet 8.
  • the final pressing of the material to be pressed 13 takes place at the main printing station 5 using the main pressure rollers 14 and 15.
  • the main pressure rollers 14 and 15 are mounted in a printing frame which, in the exemplary embodiment shown in FIG. 2, consists of two carriers 16 and 17, which are connected by a rod 18.
  • a servomotor M 1 ' which is provided with a gear.
  • the servomotor M 1 acts on a spindle 22 which is in engagement with a worm wheel 21.
  • This worm wheel 21 sits on a threaded spindle 20 which is seated with its end sections in threaded sleeves 23 and 24.
  • the spindle 22 rotates, the worm wheel 21 and thus the spindle 20 rotate.
  • the two end sections of the rod 18 are adjusted in relation to one another or from one another in accordance with the double arrow 19, so that the distance between the main pressure rollers 14 and 15 is adjusted.
  • the mutual distance between the main pressure rollers 14 and 15 is increased by actuating the servo motor M 1 when a predetermined pre-pressing force limit is exceeded in accordance with the following illustration.
  • the form rollers 11 and 12 are held in a known - and not shown in the drawing - type of a carrier, which is provided with strain gauges with which the deflection of the carrier, which is dependent on the pre-pressing force of the form rollers 11 and 12 and the Stamp 9 and 10, measure and convert into voltage signals that are proportional to the pre-pressure.
  • the strain gauges are connected according to the principle of a full bridge or a Wheatstone bridge, as shown in FIG. 3.
  • the change in voltage that occurs in the strain gauges or bridge 25 during pressing is amplified to a microprocessor 27 via an amplifier 26.
  • the signals are evaluated taking into account the predetermined pressing force limits and if a pre-pressing force limit is exceeded, a signal is sent to the servomotor M, for adjusting the main pressure rollers 14 and 15 and to the main drive motor M 2 of the die plate 1 for stopping its circulation.
  • the pre-pressing force V is regularly smaller than the main pressing force H.
  • the main pressing force H must be prevented from exceeding a predetermined pressing force quantity B, since then there is a risk of a stamp break.
  • the size of the pre-compression force V is taken into account. If the pre-pressing force V is below a predetermined pre-pressing force quantity A, it can be assumed that the subsequent main pressing force H is also below the tolerance limit B. However, if the pre-pressing force V 2 exceeds the predetermined limit A, it must be expected that the subsequent main pressing force H 2 will also exceed the tolerance limit B.
  • the adjustable size A is exceeded by the pre-pressing force V 3
  • the machine is stopped and the main pressure rollers are moved apart, so that subsequently a main pressing force H 3 to be measured is far below the tolerance limit B.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Medical Preparation Storing Or Oral Administration Devices (AREA)
  • Press Drives And Press Lines (AREA)
  • Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)

Description

Die Erfindung betrifft eine Rundläufer-Tablettiermaschine zum Verdichten vonThe invention relates to a rotary tablet machine for compressing

pulverförmigem oder körnigem Preßgut, die eine drehbare Matrizenscheibe und über den Umfang verteilt angeordnete Matrizen sowie über und unter der Matrizenscheibe angeordnete Ober-und Unterstempel aufweist, mit denen das Preßgut durch einstellbare Vordruck- und Hauptdruckrollen zu Tabletten zu pressen ist, bei der eine Hauptdruckrolle mit einem durch einen Rechner gesteuerten Stellmotor versehen ist, mit dem der Abstand zwischen den Hauptdruckrollen zueinander zu verändern ist.Powdery or granular pressed material, which has a rotatable die plate and matrices distributed over the circumference as well as upper and lower punches arranged above and below the die plate, with which the pressed material can be pressed into tablets by means of adjustable pre-pressure and main pressure rollers, in which a main pressure roller is also used a servomotor controlled by a computer is provided, with which the distance between the main pressure rollers can be changed.

Derartige Rundläufer-Tablettiermaschinen werden benutzt zur Herstellung von Preßlingen aus den Verschiedenartigsten Materialien, also nicht nur zur Herstellen von Tabletten aus Arzneimitteln, die für den Verbrauch durch den Menschen bestimmt sind, sondern auch von Preßlingen beispielsweise aus Kunststoff oder einen Metallpulver oder einer keramischen Masse. Die Herstellung der einzelnen Tablette erfolgt dadurch, daß die pulverförmige Preßmasse in einer Matrize einer umlaufenden Matrizenscheibe zwischen einem Oberstempel und einem Unterstempel zusammengepreßt wird. Die Kraft zum Komprimieren der Preßmasse an der Hauptdruckstation wird dadurch erzeugt, daß der Oberstempel und der Unterstempel zwischen Hauptdruckrollen hindurchgeführt werden, deren Abstand zueinander durch einen Stellmotor verändert werden kann, um die Größe der Hauptpreßkraft vorgeben zu können. (DE-A-3 131 402).Such rotary tablet machines are used for the production of compacts from a wide variety of materials, i.e. not only for the manufacture of tablets from medicinal products intended for human consumption, but also for compacts, for example made of plastic or a metal powder or a ceramic mass. The individual tablets are produced by compressing the powdery molding compound in a die of a rotating die between an upper punch and a lower punch. The force for compressing the molding compound at the main printing station is generated in that the upper punch and the lower punch are passed between main pressure rollers, the distance between which can be changed by an actuator in order to be able to specify the size of the main pressing force. (DE-A-3 131 402).

Bei modernen Hochleistungs-Tablettiermaschinen erfolgt bereits vor der Hauptdruckstation eine Vorverdichtung der Preßmasse an einer Vordruckstation unter Anwendung einer Vorpreßkraft. Diese Vorpreßkraft ist in der Regel erheblich geringer als die Hauptpreßkraft. Beispielsweise liegt die Vorpreßkraft bei 10 kN (Kilo Newton) und die Hauptpreßkraft bei 40 kN. (Ausstellung "ACHEMA" Frankfurt am Main 1979; Maschine Typ Perfecta 1000).In modern high-performance tableting machines, the molding compound is pre-compressed at a pre-printing station using a pre-pressing force before the main printing station. This pre-pressing force is usually considerably less than the main pressing force. For example, the pre-pressing force is 10 kN (Kilo Newton) and the main pressing force is 40 kN. (Exhibition "ACHEMA" Frankfurt am Main 1979; machine type Perfecta 1000).

Vielfach sind zum Herstellen von Tabletten so hohe Hauptpreßkräfte erforderlich, daß sie nahe an der zulässigen Belastungsgrenze der Stempel zum Fressen liegen. Durch Betriebsstörungen wie beispielsweise Doppelfüllungen, kann eine Oberschreitung der Grenze der zulässigen Belastung eines Hauptpreßstempels eintreten, so daß eine Stauchung oder ein Bruch des Stempels auftritt. Um dem zu begegnen ist es bekannt, hydraulisch oder mit Federn vorgespannte Überdrucksicherungen vorzusehen. Diese Mittel weisen jedoch den entscheidenden Nachteil auf, daß sie relativ träge sind infolge der großen zu bewegenden Masse, so daß bei schnell laufenden Hochleistungsmaschinen ein ausreichendes Ausweichen der Hauptdruckrollen innerhalb der kurzen zur Verfügung stehenden Zeit nicht möglich ist, denn die Zeit, innerhalb der das Signal der Hauptpreßkraft ansteht und in der folglich auch das Druckrahmensystem ausweichen muß, beträgt bei hohem Tablettenausstoß nur wenige Millisekunden. Das hat zur Folge, daß bei hohen Leistungen der Tablettenmaschinen trotz vorgesehener Überdrucksicherungen ein Stempelbruch nicht auszuschließen ist.In many cases, the main pressing forces required to manufacture tablets are so high that they are close to the permissible load limit of the punches for eating. Due to malfunctions such as double fillings, the limit of the permissible load of a main press ram can be exceeded, causing the ram to compress or break. In order to counter this, it is known to provide overpressure safeguards that are preloaded hydraulically or with springs. However, these agents have the decisive disadvantage that they are relatively sluggish due to the large mass to be moved, so that in high-speed, high-speed machines, it is not possible to sufficiently avoid the main pressure rollers within the short time available, because the time within which Signal of the main pressing force is present and in which consequently the pressure frame system has to dodge, is only a few milliseconds with high tablet output. The consequence of this is that, in the case of high performance of the tablet machines, a breakage of the stamp cannot be ruled out despite the provided overpressure safeguards.

Aufgabe der vorliegenden Erfindung ist es, eine Tablettiermaschine und ein Verfahren zur Steuerung seiner Druckrollen zu schaffen, welche die Gefahr des Auftretens von Stempelbrüchen an der Hauptpreßstation vermindert. Gemäß der Erfindung ist dafür vorgesehen, daß ein Rechner den Stellmotor für den Abstand der Hauptdruckrollen aufgrund der gemessenen Preßkraft der Vordruckrollen steuert. Nach der Erfindung wird somit bereits an der Vordruckstation die Vorpreßkraft jedes Stempels gemessen und ausgewertet. Wenn diese Vorpreßkraft auch erheblich niedriger ist als die Hauptpreßkraft an der Hauptdruckstation, so läßt ihre Größe doch einen Rückschluß auf die Größe der zu erwartenden Hauptpreßkraft zu. Demzufolge kann bereits anhand der Größe der Vorpreßkraft erkannt werden, ob die Preßkraft an der Hauptdruckstation die zulässige Stempelbelastung überschreiten wird. Nach der Erfindung wird deshalb eine Grenze für die Vorpreßkraft vorgegeben, bei deren Überschreiten durch das Maximum der Vorpreßkraft die Presse schlagartig gestoppt wird, so daß die betreffende vorgepreßte Tablette mit ihren zugehörigen Stempeln nicht die Hauptdruckrollen erreicht. Diese werden gleichzeitig oder nach der Stillsetzung der Matrizenscheibe automatisch um eine bestimmte Größe auseinandergefahren, so daß die Stempel mit der zu hohen Vorpreßkraft ohne überhöhte Hauptpreßkraft und ohne die Gefahr einer Beschädigung zwischen den Auseinandergefahrenen Hauptdruckrollen rechnergesteuert hindurchzufahren sind. Danach wird die Tablettiermaschine erneut gestoppt, "um einen Ausstoß von zu vielen Schlechttabletten zu vermeiden, der eintreten würde in der Zeit der Rückstellung der Hauptdruckrollen auf den ursprünglich vorgesehenen Abstand. Ist diese Rückstellung erfolgt, so wird die Fertigung der Tabletten selbsttätig fortgesetzt.The object of the present invention is to provide a tabletting machine and a method for controlling its pressure rollers, which reduces the risk of stamp breaks occurring at the main pressing station. According to the invention it is provided that a computer controls the servomotor for the distance between the main pressure rollers based on the measured pressing force of the pre-pressure rollers. According to the invention, the pre-pressing force of each punch is thus measured and evaluated at the pre-printing station. Even if this pre-pressing force is considerably lower than the main pressing force at the main pressure station, its size allows a conclusion to be drawn about the size of the main pressing force to be expected. As a result, it can already be recognized from the size of the pre-pressing force whether the pressing force at the main printing station will exceed the permissible punch load. According to the invention, therefore, a limit is set for the pre-pressing force, when exceeded by the maximum of the pre-pressing force, the press is stopped suddenly, so that the pre-pressed tablet in question does not reach the main pressure rollers with their associated stamps. These are automatically moved apart by a certain size at the same time or after the die plate is shut down, so that the punches with the excessive pre-pressing force can be passed through in a computer-controlled manner without excessive main pressing force and without the risk of damage between the main pressure rollers which have moved apart. The tabletting machine is then stopped again "in order to avoid expelling too many bad tablets, which would occur when the main pressure rollers were reset to the originally intended distance. Once this reset has been carried out, the tablets continue to be produced automatically.

Die Hauptdruckrollen sind dafür vorzugsweise in Trägern gelagert, deren Abstand durch den Stellmotor verstellbar ist.For this purpose, the main pressure rollers are preferably mounted in supports whose spacing can be adjusted by the servomotor.

Dafür ist der Stellmotor getriebeartig mit einem längenverstellbaren Stab gekoppelt, der mit den Trägern der Hauptdruckrollen verbunden ist, wobei die Hauptdruckrollen in einem parallelogrammartigen Druckrahmen gelagert sein können.For this purpose, the servomotor is coupled in a gear-like manner to a length-adjustable rod which is connected to the carriers of the main pressure rollers, the main pressure rollers being able to be mounted in a parallelogram-type pressure frame.

Die Steuerung des Stellmotors für die Hauptdruckrollen sowie des Antriebsmotors für die Matrizenscheibe erfolgt vorzugsweise unter Anwendung eines Mikroprozessors, der an Dehnungsmeßstreifen angeschlossen ist, mit denen sich die Vorpreßkräfte der Vordruckrollen in bekannter Weise messen lassen.The control of the servomotor for the main pressure rollers and the drive motor for the die plate is preferably carried out using a microprocessor which is connected to strain gauges, with which the pre-pressing forces of the pre-pressure rollers have it measured in a known manner.

Ein Ausführungsbeispiel der Erfindung ist nachstehend unter Bezugnahme auf eine Zeichnung erläutert. In der Zeichnung zeigen:

  • Figur 1: die Draufsicht auf eine Rundläufer-Tablettiermaschine in schematischer Darstellung
  • Figur 2:-eine Abwicklung mit der Vor- und Hauptpreßstation, teilweise in vergrößerter Darstellung
  • Figur 3: die Schaltung für die Steuerung der Motore
  • Figur 4: die Preßkräfte im Diagramm
An embodiment of the invention is explained below with reference to a drawing. The drawing shows:
  • Figure 1: The plan view of a rotary tablet machine in a schematic representation
  • Figure 2: -A processing with the pre and main press station, partially in an enlarged view
  • Figure 3: the circuit for the control of the motors
  • Figure 4: the pressing forces in the diagram

Die in der Zeichnung wiedergegebene Rundläufer-Tablettiermaschine besitzt eine entsprechend dem Pfeil 7 umlaufende Matrizenscheibe 1, die mit Matrizen 2 versehen ist, welche gleichmäßig über den Umfang verteilt angeordnet sind.The rotary tablet machine shown in the drawing has a die plate 1 rotating around the arrow 7, which is provided with dies 2, which are arranged evenly distributed over the circumference.

Für die Herstellung von Tabletten werden die Matrizen 2 an einer Füllstation 3 mit Preßgut gefüllt, das an einer Vordruckstation 4 unter Anwendung der Vordruckrollen 11 und 12 (Figur 2) vorgepreßt wird. Diese Vordruckrollen 11 und 12 wirken auf den zu jeder Matrize gehörigen Oberstempel 9 und Unterstempel 10 zum Vorpressen einer Tablette 8 ein.For the production of tablets, the matrices 2 are filled at a filling station 3 with material to be pressed, which is pre-pressed at a pre-printing station 4 using the pre-pressure rollers 11 and 12 (FIG. 2). These pre-pressure rollers 11 and 12 act on the upper punch 9 and lower punch 10 associated with each die for pre-pressing a tablet 8.

Nach dem Vorpressen an der Vordruckstation 4 erfolgt das endgültige Zusammenpressen des Preßgutes 13 an der Hauptdruckstation 5 unter Anwendung der Hauptdruckrollen 14 und 15. Die Hauptdruckrollen 14 und 15 sind in einem Druckrahmen gelagert, der in dem in Figur 2 wiedergegebenen Ausführungsbeispiel aus zwei Trägern 16 und 17 besteht, die durch einen Stab 18 miteinander verbunden sind. Selbstverständlich besteht die Möglichkeit, davon abweichend die Druckrollen 14 und 15 andersartig zu lagern. Von Bedeutung ist jedoch, daß ihr gegenseitiger Abstand verstellbar ist durch einen Stellmotor M1' der mit einem Getriebe versehen ist.After the pre-pressing at the pre-printing station 4, the final pressing of the material to be pressed 13 takes place at the main printing station 5 using the main pressure rollers 14 and 15. The main pressure rollers 14 and 15 are mounted in a printing frame which, in the exemplary embodiment shown in FIG. 2, consists of two carriers 16 and 17, which are connected by a rod 18. Of course, there is the possibility of storing the pressure rollers 14 and 15 differently. It is important, however, that their mutual distance is adjustable by means of a servomotor M 1 ' which is provided with a gear.

Der Stellmotor M1 wirkt auf eine Spindel 22, die mit einem Schneckenrad 21 im Eingriff steht. Dieses Schneckenrad 21 sitzt auf einer Gewindespindel 20, die mit ihren Endabschnitten in Gewindehülsen 23 und 24 sitzt.The servomotor M 1 acts on a spindle 22 which is in engagement with a worm wheel 21. This worm wheel 21 sits on a threaded spindle 20 which is seated with its end sections in threaded sleeves 23 and 24.

Bei einem Umlauf der Spindel 22 rotiert das Schneckenrad 21 und damit die Spindel 20. Je nach der Drehrichtung der Spindel 20 werden die beiden Endabschnitte des Stabes 18 entsprechend dem Doppelpfeil 19 zueinander oder voneinander fort verstellt, so daß damit auch der Abstand der Hauptdruckrollen 14 und 15 verstellt wird. Eine Vergrößerung des gegenseitigen Abstandes der Hauptdruckrollen 14 und 15 durch Betätigung des Stellmotors M1 erfolgt bei Überschreiten einer vorgegebenen Vorpreßkraftgrenze entsprechend der nachfolgenden Darstellung.When the spindle 22 rotates, the worm wheel 21 and thus the spindle 20 rotate. Depending on the direction of rotation of the spindle 20, the two end sections of the rod 18 are adjusted in relation to one another or from one another in accordance with the double arrow 19, so that the distance between the main pressure rollers 14 and 15 is adjusted. The mutual distance between the main pressure rollers 14 and 15 is increased by actuating the servo motor M 1 when a predetermined pre-pressing force limit is exceeded in accordance with the following illustration.

Die Vordruckrollen 11 und 12 sind in bekannter - und in der Zeichnung nicht wiedergegebener - Art von einem Träger gehalten, der mit Dehnungsmeßstreifen versehen ist, mit denen sich die Durchbiegung des Trägers, die abhängig ist von der Vorpreßkraft der Vordruckrollen 11 und 12 bzw. der Stempel 9 und 10, messen und in Spannungssignale umwandeln läßt, die dem Vorpreßdruck proportional sind. Die Dehnungsmeßstreifen sind dafür nach dem Prinzip einer Vollbrücke bzw. einer Wheatstoneschen Brücke geschaltet entsprechend der Darstellung in Figur 3. Die Spannungsänderung, die in den Dehnungsstreifen bzw. der Brücke 25 beim Pressen auftritt, wird über einen Verstärker 26 verstärkt auf einen Mikroprozessor 27 gegeben. In diesem Mikroprozessor 27 erfolgt eine Auswertung der Signale unter Berücksichtigung der vorgegebenen Preßkraftgrenzen und bei Überschreitung einer Vorpreßkraftgrenze eine Signalgebung auf den Stellmotor M, für eine Verstellung der Hauptdruckrollen 14 und 15 sowie auf den Hauptantriebsmotor M2 der Matrizenscheibe 1 für eine Stillsetzung ihres Umlaufes.The form rollers 11 and 12 are held in a known - and not shown in the drawing - type of a carrier, which is provided with strain gauges with which the deflection of the carrier, which is dependent on the pre-pressing force of the form rollers 11 and 12 and the Stamp 9 and 10, measure and convert into voltage signals that are proportional to the pre-pressure. For this purpose, the strain gauges are connected according to the principle of a full bridge or a Wheatstone bridge, as shown in FIG. 3. The change in voltage that occurs in the strain gauges or bridge 25 during pressing is amplified to a microprocessor 27 via an amplifier 26. In this microprocessor 27, the signals are evaluated taking into account the predetermined pressing force limits and if a pre-pressing force limit is exceeded, a signal is sent to the servomotor M, for adjusting the main pressure rollers 14 and 15 and to the main drive motor M 2 of the die plate 1 for stopping its circulation.

Entsprechend der Figur 4, in der die Größe F der Preßkräfte über der Zeit bei drei verschiedenen Betriebszuständen aufgezeigt ist, ist die Vorpreßkraft V regelmäßig kleiner als die Hauptpreßkraft H. Beim Betrieb ist zu verhindern, daß die Hauptpreßkraft H eine vorgegebene Preßkraftgröße B überschreitet, da dann die Gefahr eines Stempelbruches gegeben ist. Dafür wird die Größe der Vorpreßkraft V berücksichtigt. Liegt die Vorpreßkraft V, unterhalb einer vorgegebenen Vorpreßkraftgröße A, so kann davon ausgegangen werden, daß die nachfolgende Hauptpreßkraft H, ebenfalls unterhalb der Toleranzgrenze B liegt. Überschreitet die Vorpreßkraft V2 hingegen die vorgegebene Grenze A, so muß damit gerechnet werden, daß die nachfolgende Hauptpreßkraft H2 ebenfalls die Toleranzgrenze B überschreitet. Um das zu verhindert, wird erfindungsgemäß bei einem Überschreiten der einstellbaren Größe A durch die Vorpreßkraft V3 die Maschine stillgesetzt und die Hauptdruckrollen auseinandergefahren, so daß nachfolgend eine zu messende Hauptpreßkraft H3 weit unterhalb der Toleranzgrenze B liegt.According to FIG. 4, in which the size F of the pressing forces is shown over time in three different operating states, the pre-pressing force V is regularly smaller than the main pressing force H. During operation, the main pressing force H must be prevented from exceeding a predetermined pressing force quantity B, since then there is a risk of a stamp break. The size of the pre-compression force V is taken into account. If the pre-pressing force V is below a predetermined pre-pressing force quantity A, it can be assumed that the subsequent main pressing force H is also below the tolerance limit B. However, if the pre-pressing force V 2 exceeds the predetermined limit A, it must be expected that the subsequent main pressing force H 2 will also exceed the tolerance limit B. In order to prevent this, according to the invention, when the adjustable size A is exceeded by the pre-pressing force V 3, the machine is stopped and the main pressure rollers are moved apart, so that subsequently a main pressing force H 3 to be measured is far below the tolerance limit B.

Claims (5)

1. Rotative tablet-compressing machine to compress powdery or grained material (13), which shows a rotative disk (1) of matrices with matrices placed and spread over its periphery as well as superior and inferior punches (9, 10) placed over or under the disk of matrices, which press the material (13) into tablets with adjustable preliminary and principal pressure rollers (11, 12, 14, 15), in which a preliminary pressure roller (14, 15) is supplied with a servomotor (M1), which is controlled by a computer (27), by which the distance between the principal pressure rollers (14,15) can be modified, characterized in that a computer (27) controlls the servomotor (M1) for the distance of the principal pressure rollers (14, 15) depending on the measured pressing power of the preliminary pressure rollers (11, 12).
2. Tablet-compressing machine according to claim 1, characterized in that a transmitter (25), which is fixed on the supports of the preliminary pressure rollers (11, 12), is connected with the servomotor (M1) of the principal pressure rollers by the computer (27).
3. Method of controlling the principal pressure rollers (14, 15) of a rotative tablet-compressing machine, in which the material is preliminary pressed in the matrices (2) of a disk of matrices (1), characterized in that the rotation of the disk of matrices (1) of the tablet-compressing machine is interrupted, when a predetermined preliminary pressing power is passed over and that the distance between the principal pressure rollers (14, 15) is increased before the tablet (8) has passed and is reduced after the tablet (8) has passed.
4. Method according to claim 3, characterized in that the rotation of the disk of matrices (1) is interrupted ahead of the principal pressure rollers after the passing through the preliminary pressure rollers (11, 12), when the preliminary pressure of the tablet (8) has been too high.
5. Method according to claim 4, characterized in that the driving motor (M2) of the disk of matrices (1) and the servomotor (M1) for the adjustment of the principal pressure rollers (14, 15) are triggered by a computer (27), when a predetermined preliminary pressing power is passed over.
EP86107315A 1985-06-05 1986-05-30 Tablet-compressing machine Expired EP0204266B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19853520203 DE3520203A1 (en) 1985-06-05 1985-06-05 ROTARY ROTARY TABLETING MACHINE AND METHOD FOR CONTROLLING YOUR PRINT ROLLERS
DE3520203 1985-06-05

Publications (2)

Publication Number Publication Date
EP0204266A1 EP0204266A1 (en) 1986-12-10
EP0204266B1 true EP0204266B1 (en) 1988-10-12

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP86107315A Expired EP0204266B1 (en) 1985-06-05 1986-05-30 Tablet-compressing machine

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US (1) US4680158A (en)
EP (1) EP0204266B1 (en)
DE (2) DE3520203A1 (en)

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US5401156A (en) * 1993-12-08 1995-03-28 Carruthers Equipment Co. Machine for inserting a sized portion of a food product into a container
US5478512A (en) * 1994-04-19 1995-12-26 H-C Industries, Inc. Method of detecting cam overload in a plastic molding apparatus
DE19502596C2 (en) * 1995-01-28 1997-08-28 Fette Wilhelm Gmbh Measuring device and computer for checking the tablets of the current production made on a rotary press
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US6106262A (en) 1997-12-25 2000-08-22 Metropolitan Computing Corporation Press simulation apparatus
DE19828004B4 (en) * 1998-06-24 2005-10-13 Korsch Ag Method for achieving a constant pressing force in tableting machines
DE19955196A1 (en) * 1999-11-16 2001-05-23 Korsch Pressen Ag Method to maintain breaking resistance of e.g. washing powder tablets etc. with constant automatic adaptation of dosing resp. compacting rollers to compensate for charging variations
DE10135283C2 (en) * 2001-07-19 2003-09-18 Fette Wilhelm Gmbh Process for pressing powder material
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Also Published As

Publication number Publication date
EP0204266A1 (en) 1986-12-10
US4680158A (en) 1987-07-14
DE3520203A1 (en) 1986-12-11
DE3660887D1 (en) 1988-11-17

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