EP2481303A1 - Cutting device for a rod device for the tobacco processing industry and method for adjusting the blade feed in a cutting device for a rod device for the tobacco processing industry - Google Patents

Abstract

The cutting device has an adjustable knife (12) that is arranged in a knife holder of knife carrier (11). A drive unit (13) drives knife carrier such that the knife blade (14) is protruded from the adjustable knife by the rotation of the knife carrier to cut strand (15) of tobacco. A control unit (16) automatically controls feed motion of knife. An angular position encoder (18) indicates angular position of the knife. An evaluation unit (19) calculates actual length of the knife carrier when knife blade is protruded from knife. An independent claim is included for method for controlling knife feed motion of cutting device.

Description

The invention relates to a cutting device for a strand machine of the tobacco-processing industry, comprising a knife carrier with at least one knife holder, in which a by means of a setting device radially adjustable knife is arranged, wherein the knife carrier is assigned a drive for rotational driving, such that the or each Knife with the knife blade protruding from the knife carrier by the rotation of the knife carrier for cutting at least one strand is engageable with this.

The invention further relates to a method for controlling the knife feed in a cutting device for a strand machine of the tobacco-processing industry, wherein the cutting device comprises a knife carrier with at least one knife holder, in which a knife radially adjustable by means of an adjusting device is arranged, and the knife carrier A drive for rotational driving is associated, such that the or each knife is engaged with the knife blade protruding from the knife carrier by the rotation of the knife carrier for cutting at least one strand therewith, comprising the steps of: monitoring the or each knife, and radial Adjusting the or each blade by means of the adjusting device in the event that the monitoring results in an actual value that deviates from a predetermined desired value.

Such cutters and methods are used in the tobacco processing industry to cut single rod-shaped articles from strands such as tobacco, blends, filter material, and other materials or combinations of materials commonly used in the tobacco processing industry. The In this case, rod-shaped articles are separated from a knife arranged on a knife carrier, which describes a running circle as a result of the rotation of the knife carrier, when the knife strikes the strand to be cut substantially perpendicularly. The usually obliquely ground blades protrude with their knife blade out of the knife carrier.

For an optimal and trouble-free cut of the strand, it is necessary that the undamaged knife protrudes with a defined length in the radial direction of the knife carrier. If the blade length projecting beyond the outer edge is too large, the knife with its knife blade protrudes too high out of the knife carrier, collisions with the counter-bearing of the knife can occur, in the worst case destroying the counter-bearing and / or the knife and then too leads to a machine downtime. If the knife length is too small, the knife with its knife blade is too deep in the knife carrier, the complete average of the strand can no longer be ensured. By cutting each knife is subject to wear. Therefore, it is common for the knives to be reground. However, the wear and / or the grinding changes the length of the knife, that is to say the section of the knife blade protruding from the knife carrier. Too small or too large blade lengths can also be caused by a faulty blade advance or a blade change. Damage to the knives, e.g. broken knives, e.g. repaired by regrinding, but also has an impact on the knife length. As a result, lead both an incorrect knife position and / or knife length and defective blades each to an unsatisfactory cut result.

So far, the position of the knife, ie in particular the protruding from the knife carrier knife length, and thus the knife feed on the basis of experience and by inspection inspected and possibly adjusted by means of the adjusting device. However, this procedure is on the one hand inaccurate and on the other hand also unreliable, since the knife feed is uncontrolled and, for example, defects on the knife at the high rotational speeds of the knife carrier can not be detected. Incidentally, the adjustment / adjustment of the knife requires a lot of experience, which is why the result of the adjustment / adjustment when the knife feed in quality of the respective operator is dependent and not reproducible.

The invention is therefore based on the object to provide a relative to the knife advance and the handling improved cutting device. The further object is to propose a corresponding method.

This object is achieved by a cutting device of the type mentioned above in that the cutting device comprises a control unit for automatic control of the knife feed. In this context, knife advance means the position of the knife relative to the knife carrier. In other words, not the speed of the adjustment but the amount, ie the change in length of the protrusion of the knife or of the knife blade beyond the knife carrier, is designated by the knife advance both to increase the length and to reduce the length. By the control unit for automatic control of the knife feed this is independent of operators and above all reproducible feasible. The automatic control allows the knife feed to be controlled during the operation of the cutting device and to react immediately quasi on-line to wrong knife lengths and / or defective knives.

Appropriately, the cutting device comprises a measuring means for outputting a signal when passing a knife on the measuring means, an angular position sensor for indicating the angular position of the knife, and an evaluation unit for assigning the angular position to the signal of the measuring means. In other words, the measuring means is designed and set up in order to detect the or each knife as it passes by and to display it in the form of an output signal with a positive and a negative edge. The evaluation unit receives the output signal of the measuring means and the indication of the angular position sensor and processes this information. With the positive edge of the output signal, the knife length can be determined. In general, the later the knife is detected, the greater the angle and the shorter the knife. Conversely, this means that the sooner the knife is detected, the smaller the angle and the longer the knife. With the negative edge of the output signal, the state of the knife can be determined. If, for example, a knife breaks out at the trailing end, the negative edge of the output signal is detected earlier, ie at a smaller angle. In other words, the solution of the invention provides an association between the output signal (positive and / or negative edge) of the measuring means and the angle of the knife, resulting from the geometry of the knife, the blade length, ie the length of protruding from the blade carrier portion, and the Derive condition of the knife. The evaluation unit then outputs a control signal.

A preferred development of the cutting device according to the invention is characterized in that the evaluation unit is designed and set up for calculating the actual actual length of the knife blade protruding from the knife carrier of the knife and / or the knife state by means of the assignment of the angular position to the signal of the measuring means. Since the knives are ground obliquely, the evaluation unit from the incoming information with the positive edge of the output signal, the length with which the knife or knife blade protrudes from the knife carrier, and the negative edge of the output signal Ausausstellen the knife exactly, for example Millimeters, calculate.

Advantageously, the control unit for determining a control signal for the adjusting device of the knife from a predetermined target length and / or a predetermined target state and the actual length and / or the actual state is formed and configured. In other words, the control unit is able to determine from a reference signal and the control signal, a difference value from which a control signal is generated. By means of this control signal then the actuator is controllable to activate the blade advance.

A particularly preferred embodiment of the invention is characterized in that the measuring means comprises at least one sensor. With this embodiment, the knife length and, secondly, the state of the knife are to be controlled in a particularly simple manner on the one hand. A single sensor is sufficient to generate a signal that is processed by the evaluation unit to calculate the actual length of the knife and the actual knife state.

A further particularly preferred embodiment of the invention is characterized in that the measuring means comprises at least two sensors. By the two spaced sensors two measuring points and thus two signals are generated. As a result, in addition to the length and condition of the knife, a statement about the pitch of the knife blade can be made. This embodiment thus also allows, for example, a check of the grinding device or of the generated grinding pattern of the knives.

A further particularly preferred embodiment of the invention is characterized in that the measuring means comprises at least three sensors. This embodiment is particularly suitable for determining the shape of the knife blade in order to control the knife feed accordingly.

Advantageously, the measuring means is designed as a fork light barrier. Thus, a fixed assignment of transmitter and receiver is achieved, which increases the precision of the signal output and thus ultimately the accuracy of the calculation of the actual length and / or the actual state. This is precisely at such high speeds of e.g. 5000 U / min, as they are achieved during the rotation of the knife carrier, of importance.

The object is also achieved by an aforementioned method in that the knife feed is automatically controlled by a control unit. The resulting advantages have already been explained in connection with the cutting device. To avoid repetition, reference is therefore made to the corresponding passages.

• Fig. 1 eine schematische Darstellung einer erfindungsgemäßen Schneideinrichtung,
• Fig. 2a eine schematische Darstellung einer Sensorerkennung für ein kurzes Messer,
• Fig. 2b eine schematische Darstellung einer Sensorerkennung für ein langes Messer,
• Fig. 3a eine schematische Darstellung einer Sensorerkennung eines unbeschädigten Messers,
• Fig. 3b eine schematische Darstellung einer Sensorerkennung eines beschädigten Messers, und
• Fig. 4 einen Signalflussplan der erfindungsgemäßen Regelung des Messervorschubs in einer Schneideinrichtung gemäß Figur 1.

Further expedient and / or advantageous features and developments of the invention will become apparent from the dependent claims and the description. A particularly preferred embodiment and the method principle according to the invention are explained in more detail with reference to the accompanying drawing. In the drawing shows:

• Fig. 1 a schematic representation of a cutting device according to the invention,
• Fig. 2a a schematic representation of a sensor detection for a short knife,
• Fig. 2b a schematic representation of a sensor detection for a long knife,
• Fig. 3a a schematic representation of a sensor detection of an undamaged knife,
• Fig. 3b a schematic representation of a sensor detection of a damaged blade, and
• Fig. 4 a signal flow chart of the inventive control of the knife feed in a cutting device according to FIG. 1 ,

The invention relates to a cutting device for a strand machine of the tobacco-processing industry.

A cutting device 10 according to FIG. 1 comprises a knife carrier 11 with at least one knife holder, not explicitly shown, in which a knife 12, which is radially adjustable by means of a setting device also not explicitly shown, is arranged. Preferably, the knife carrier 11 has two or more knife holders, each with a knife. The blade carrier 11 is associated with a drive 13 for rotational driving, such that the or each blade 12 is engageable with the knife blade 14 protruding from the knife carrier 11 by the rotation of the knife carrier 11 for cutting at least one strand 15 with this. Such cutting devices 10 are well known, which is why a more detailed description and representation of all the details in the figures is omitted. According to the invention, the cutting device 10 is assigned a control unit 16 for automatic control of the knife feed. In other words, the cutting device 10 according to the invention comprises a control unit 16 by means of which the knives 12 are automatically adjustable in the radial direction with the aid of the adjusting device.

The features and embodiments described below represent further developments of the cutting device 10 according to the invention, which can be implemented individually or in combination with each other.

The embodiment shown comprises two blades 12. However, the cutting device 10 can also be equipped with only one blade 12 or more than two blades 12. The blades 12 themselves are arranged at least in the radial direction outwardly adjustable in the knife holder. Optionally, however, it is also possible to provide an adjustment possibility directed inwardly towards the center M of the knife carrier 11. When rotating the knife carrier 11 each knife 12 describes a running circle. In this running circle are the strands 15 to be cut. In other words, the running circle of the knives 12 crosses the strands 15 to be cut, so that the engagement of the knives 12 in the strands 15 leads to the complete severing thereof. When cutting, ie during operation of the cutting device 10, each knife 12, which is ground obliquely, projects beyond the outer edge of the knife carrier 11. Due to the oblique shape or the oblique cut of the knife blade 14, each knife 12, seen in the direction of rotation R, projects longer with the trailing end out of the knife carrier 11 than with the leading end. The longer length of the blade 12 defines the actual blade length h. As a result, each knife 12 first strikes the or each strand 15 with the shorter knife length, in order then to ensure the complete average of each strand 15 by the rotation of the knife carrier 11 and the increasing knife length up to the knife length h.

The cutting device 10 comprises a measuring means 17 for outputting a signal when passing a knife 12 on the measuring means 17, an angular position sensor 18 for indicating the angular position of the knife 12 and an evaluation unit 19 for assigning the angular position to the signal of the measuring means 17. As measuring means 17 are suitable All common components that detect the passage / passing the blade 12 on the measuring means 17 and display. Especially suitable are sensors, eg simple light barriers. As angular position sensor 18 also all common types are used, in particular all sensors for detecting a rotation angle or its change to a shaft relative to a fixed part. The angular position sensors 18 can be designed as analog or digital components.

The evaluation unit 19 may e.g. be a computer or control unit. Accordingly, the evaluation unit 19 for calculating the actual actual length (as a control signal) of the knife carrier 11 protruding from the knife blade 11 of the knife 12 and / or the actual knife state by means of the assignment of the angular position to the signal of the measuring means 17 and be configured. This means that the evaluation unit 19 due to the geometry of the knife 12 with the oblique knife blade 14 from the collected data, namely the angular position of the blade 12 and the signal of the measuring means 17, the actual length of the blade 12 and / or the actual width of the blade 12 can calculate. The control unit 16 is for determining a control signal for the adjusting device of the blade 12 from a reference signal, namely here the desired length and / or a predetermined target state (eg full nominal width corresponds to the desired state), and the control signal, here the actual Length and / or the actual state, trained and set up.

With regard to the design and arrangement of the measuring means 17, there are different possibilities. In an embodiment, the measuring means 17 comprises a sensor. By means of this one sensor, the positive edge of the signal can be used to determine the blade length, e.g. in mm. With the negative edge of the signal it can be calculated whether the blade 12 is undamaged or e.g. has broken out. This is done e.g. over the blade width. The evaluation unit 19 can also be used to determine the degree of damage, e.g. in mm. In a further embodiment of the measuring means 17, this may have two sensors. As a result, in addition to the results already mentioned, it is also necessary to make a statement about the slope of the knife 12 or the knife blade 14. In a further embodiment, the measuring means 17 has three sensors or more. With more than two sensors, the actual shape of the knife 12 or the knife blade 14 can be calculated.

The multiple sensors can be arranged in a single measuring module. In this embodiment, the sensors can be arranged one above the other, one behind the other, offset from one another and in any other way from each other. With a single measuring module there is also only one building site for the measuring means 17. This building site, that is to say the allocation of the measuring means 17 to the knife carrier 11, is located Preferably, on the or the each strand 15 opposite side of the knife carrier 11. However, the position of the measuring means 17 may also vary. With regard to the distance of the measuring means 17 to the knife carrier 11, it is preferred that the measuring means 17 is arranged at a distance from the center M of the knife carrier 11, which corresponds to the distance from the center M of the knife carrier 11 to the central axis of the strand 15 to be cut. However, as long as the blade 12 or the knife blade 14 is arranged in a distance to the knife carrier 11 that triggers the signal by the measuring means 17, each distance of the measuring means 17 to the knife carrier 11 is variable. There is also the possibility that several individual measuring modules, each of which carries at least one sensor, form the measuring means 17. The individual measuring modules can be arranged in different ways to the blade carrier 11, that is to say at different building sites. Particularly advantageous is the formation of the measuring means 17 has shown as fork light barrier. Such a forked light barrier has in fixed association with one another on opposite sides at least one transmitter and at least one corresponding receiver.

Overall, the inventive design of the cutting device 10 is a closed loop. This is formed by the blade carrier 11 with the associated measuring means 17 and angular position sensor 18 together with the evaluation unit 19 and the control unit 16. In the knowledge of the calculated by the evaluation unit 19 blade length and / or the knife state can be responded to changes in the blade length and / or changes in the blade state directly and controlled by the blade advance is controlled on the basis of the control signal. In addition to checking the blade length, eg after a blade change, the setting and the condition of the grinding device, which is usually associated with the blades 12 of the cutting device 10, can be checked. Damage to the blade 12 can be reduced or even completely eliminated by a targeted increase in the blade advance. The control signals from the control unit 16 may further be displayed as a warning or stop message, for example via suitable acoustic and / or optical components.

• Beim Schneiden von Strängen 15 der Tabak verarbeitenden Industrie rotiert der Messerträger 11 umlaufend, so dass das oder jedes daran angeordnete Messer 12 einen Laufkreis beschreibt. Die Messer 12 können beim Rotieren neben dem Eingriff in den oder jeden Strang 15 auch noch mit Schleifscheiben einer Schleifeinrichtung in Kontakt kommen. Durch das Schneiden der Stränge und/der das Nachschleifen der Messer 12 verändert sich die Länge der Messer 12, genauer die Länge der aus dem Messerträger 11 herausragenden Messerklingen 14. Geht man in einem Beispiel davon aus, dass die Messerklingen 14 mit einer Messerlänge h als Sollwert von 10mm aus dem Messerträger 12 herausragen, reduziert sich diese Länge durch Verschleiß und/oder Schleifen. Um ein Unterschreiten einer kritischen Länge (z.B. bei einem Ist-Wert von 9mm im vorliegenden Beispiel), bei der die Messer 12 den oder jeden Strang 15 nicht mehr zuverlässige durchschneiden, erkennen zu können, wird jedes Messer überwacht. Durch eine Erhöhung des Messervorschubs durch Betätigen der Verstelleinrichtung wird das entsprechende Messer radial nachgestellt, sobald die kritische Länge unterschritten ist. Das Messer 12 kann beim Schneiden und/oder Schleifen auch ausbrechen, also Beschädigungen an der Messerklinge 14 aufweisen. Um solche Schäden zu begrenzen oder ganz zu beheben, wird ebenfalls der Messervorschub erhöht.

The method principle is explained in more detail below by way of example with reference to the drawing:

• When cutting strands 15 of the tobacco processing industry, the knife carrier 11 rotates circumferentially, so that the or each arranged thereon knife 12 describes a running circle. The blades 12 may come in contact with the rotation in addition to the engagement in the or each strand 15 also with grinding wheels of a grinding device in contact. By cutting the strands and / or the regrinding of the blades 12, the length of the blades 12 changes, more precisely, the length of the knife blades 14 projecting from the blade carrier 11. If, in an example, it is assumed that the blade blades 14 have a blade length h Specification of 10mm protrude from the blade carrier 12, this length is reduced by wear and / or grinding. In order to be able to detect falling below a critical length (for example, with an actual value of 9 mm in the present example), at which the knives 12 no longer reliably cut through the or each strand 15, each knife is monitored. By increasing the blade advance by operating the adjusting device, the corresponding blade is readjusted radially as soon as the critical length is reached. The knife 12 may also break when cutting and / or grinding, so have damage to the knife blade 14. In order to limit or completely eliminate such damage, the knife advance is also increased.

According to the invention, the knife feed is automatically controlled by the control unit 16. This means that the results on the knife length and the knife state resulting from the monitoring directly and automatically lead to the setting device receiving a control signal for changing the knife feed. The monitoring of the knife length and / or the knife state is performed by the measuring means 17 and the angular position sensor 18 in conjunction with the evaluation unit 19. When passing a knife 12 on the measuring means 17, a signal S _{1 is} output. The angular position sensor 18 outputs a signal S ₂ to the current angular position of the blade 12 permanently. The two signals S ₁ and S ₂ are assigned to one another in the evaluation unit 19. From the assignment, the evaluation unit 19 calculates the actual actual value (actual length and / or actual state) of the blade 12 and generates a signal S ₃ as a control signal. In this case, the positive edge of the signal S ₁ for calculating the Knife length used. With the negative edge of the signal S ₁ , the state of the blade 12 is calculated or determined.

Such as from the FIG. 2a can be seen, the knife 12 hits with a short blade length h _small later, ie in the direction of rotation R at a larger angle of the blade carrier 11, the measuring means 17, while a knife 12 with a larger blade length h _large (see FIG. 2b ) rather, so at a smaller angle, the measuring means 17 hits. Basically, the later the blade 12 is detected, the greater the angle and vice versa. Upon detection of broken knives 12 (see FIGS. 3a and 3b ), the negative edge of the signal S _{1 is} used. If the knife 12 has broken out, for example, at the trailing end (see FIG. 3b ), the negative edge of the signal S _{1 is} detected at a smaller angle of the blade carrier 11. If the knife 12 is intact (see FIG. 3a ), the negative edge of the signal S ₁ is detected later, ie at a larger angle.

The output by the evaluation unit 19 signal S ₃ as a control signal is compared with a signal S ₄ as a reference signal. For example, by subtraction one obtains the signal S ₅ as an input signal into the control unit 16. Therein a control signal S _{6 is} generated and forwarded to the blade carrier 11 or more precisely to the adjusting device. With the control signal S ₆ , the blade advance of the blade 12 is actuated, wherein the blade advance can lead to the increase or decrease of the blade length in dependence of the signal S ₆ . It is thus formed a closed loop. The blades 12 of a blade carrier 11 can be synchronously or separately monitored and readjusted.

By means of the control unit 16, it is thus possible to check and readjust the blade length quite generally. With the invention, it is also possible to check the setting and the state of the grinding device and to respond to it. Malfunctions of the knife feed can also be detected and corrected. After a knife change, the knives 12 can be advanced quickly to the optimum knife length. By specifically increasing the blade advance damage to the blade 12 can be reduced or eliminated. The signals obtained by the monitoring and control can furthermore be used for this purpose to generate warning messages and / or stop messages to prevent damage to the blade carrier 11, the blades 12 or other components of the cutting device 10.

Claims (12)

Cutting device (10) for a stranding machine of the tobacco processing industry, comprising a knife carrier (11) with at least one knife holder, in which a by means of an adjusting device radially adjustable knife (12) is arranged, wherein the knife carrier (11) has a drive (13) for associated with rotating driving, such that the or each blade (12) with the knife blade (14) protruding from the knife carrier (11) by the rotation of the knife carrier (11) for cutting at least one strand (15) is engageable with this , characterized in that the cutting device (10) comprises a control unit (16) for automatic control of the knife feed. Cutting device according to claim 1, characterized in that the cutting device (10) comprises a measuring means (17) for outputting a signal when passing a knife (12) on the measuring means (17), an angular position sensor (18) for indicating the angular position of the knife (12 ) and an evaluation unit (19) for assigning the angular position to the signal of the measuring means (17). Cutting device according to claim 2, characterized in that the evaluation unit (19) for calculating the actual actual length of the knife carrier (11) protruding knife blade (14) of the knife (12) and / or the knife state by means of the assignment of the angular position to the signal the measuring means (17) is designed and set up. Cutting device according to claim 3, characterized in that the control unit (16) for determining a control signal for the adjusting device of the blade (12) from a predetermined target length and / or a predetermined desired state and the actual length and / or the actual Condition is trained and set up. Cutting device according to one of claims 2 to 4, characterized in that the measuring means (17) comprises at least one sensor. Cutting device according to claim 2 or 5, characterized in that the measuring means (17) comprises at least two sensors. Cutting device according to one of claims 2 to 6, characterized in that the measuring means (17) comprises at least three sensors. Cutting device according to one of claims 2 to 7, characterized in that the measuring means (17) is designed as a fork light barrier. Cutting device according to one of claims 2 to 7, characterized in that the measuring means (17) on the or each strand (15) opposite side of the knife carrier (11) is arranged. Cutting device according to one of claims 2 to 9, characterized in that the measuring means (17) is arranged at a distance from the center M of the knife carrier (11), which corresponds to the distance from the center M of the knife carrier (11) to the central axis of the strand to be cut , Method for controlling the knife feed in a cutting device (10) for a stranding machine of the tobacco-processing industry, wherein the cutting device (10) has a knife carrier (11) with at least one knife holder in which a knife (12) radially adjustable by means of an adjusting device is arranged, comprises, and the knife carrier (11) is associated with a drive (13) for rotating driving, such that the or each blade (12) with the knife blade (14) protruding from the knife carrier (11) by the rotation of the knife carrier (11) for cutting at least one strand (15) therewith, comprising the steps of: - monitoring the or each blade (12), and - Radial adjustment of the or each blade (12) by means of the adjusting device in the event that the monitoring results in an actual value that deviates from a predetermined target value, characterized in that the blade feed is controlled automatically by a control unit (16) , A method according to claim 11, characterized in that from an assignment of a signal from a measuring means (17) which outputs a signal when passing a knife (12) on the measuring means (17) to an angular position of the knife (12) an actual actual Length of the knife blade protruding from the knife carrier of the knife and / or an actual actual state is calculated or determined, which is compared with a desired length and / or a desired state to from a control signal for the actuator to produce.

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