DE102023126035A1 - Method for automatically adjusting the transverse position of the knife of a slicing machine and slicing machine suitable therefor - Google Patents

Abstract

In order to provide the knife (3) with optimal cutting conditions at all times, the load on the knife (3) is first measured in a starting position (AP) in the X and Y directions during slicing operation. The knife (3) is then moved in at least one of the two directions to several measuring positions (MP1, MP2, MP3), and the load on the knife (3) is also measured there during slicing operation. For the subsequent slicing operation, the knife axis (3') and thus the knife (3) are adjusted to the position in the X and Y directions for which the measurements at the measuring positions (MP1, MP2, MP3) resulted in an optimally low load.

Description

I. Area of application

The invention relates to slicing machines for slicing strand-shaped food products, so-called calibres, into slices, in particular high-speed slicing machines such as slicers, which are used primarily for slicing sausage or cheese calibres.

II. Technical background

In order to minimize wear on the knife and to keep the load on the knife drive as low as possible, as well as to reduce power consumption and consequently achieve the best possible cutting pattern on the slices and portions produced, it is important that the knife is subjected to as little load as possible during slicing, especially in the circumferential direction around the knife axis.

The load on the knife can be identified by the torque measurable on the knife or its knife drive and/or the current consumption of the knife motor during slicing operation.

• Hierfür sind Optimierungsmethoden bekannt.

The always correct, automatic adjustment of the cutting gap, i.e. the distance between the knife plane in which the cutting edge of the knife rotates, and a counter edge, especially measured in the direction of the knife's rotation axis, the Z-direction or axial direction, is essential for both the cutting result and the durability of the knife:

• Optimization methods are known for this purpose.

Furthermore, the load on the knife, especially in the circumferential direction around its axis of rotation, is also influenced by the position of the knife axis in the two transverse directions X and Y to the axial direction, primarily by the position in the Y direction, which is perpendicular to the axial direction as well as to the width direction, the X direction, of the slicing machine as viewed from above.

This determines the entry angle and the inclination of the cutting edge when entering and/or exiting the calibers, which are usually arranged next to one another and are to be cut at the same time, which influences the extent to which the cut made by the usually sickle-shaped knife is a pulling cut or a pushing cut.

In both cases, impurities adhering to the cutting edge of the knife or the counter edge can distort the measurement result of the load on the knife during slicing, which must also be taken into account.

III. Description of the invention

a) Technical task

It is therefore the object of the invention to provide a method for automatically adjusting the cutting gap when the knife is rotating, not only when idling but also during slicing operation, in order to be able to automatically adapt the cutting gap to the environmental parameters currently present at the knife, such as the basic type of product, product consistency, number of tracks, caliber size, caliber volume, product temperature, in particular at the cutting point, slice thickness, possible contact with the cutting frame, etc., and to provide a slicing machine suitable for this purpose.

b) Solution to the task

This object is achieved by the features of claims 1 and 13. Advantageous embodiments emerge from the subclaims.

First of all, it must be clarified that the operating torque of a knife around the axis of rotation of the knife during slicing operation is also subject to fluctuations within each revolution of the knife, depending on the environmental parameters mentioned, which also change during one revolution of the knife.

This is even more pronounced with sickle knives than with planetary orbiting circular disc knives.

• a) vor Beginn des Aufschneide-Betriebes die Messerachse in X- und Y-Richtung auf eine vorgegebene Ausgangs-Position einzustellen. Diese kann auf Erfahrungswerten basieren, insbesondere einem Erfahrungswert für das Einstellen in X- und Y-Richtung aus einem früheren Auftrag mit ähnlichen Aufschneide-Parametern wie beim neuen Auftrag,
• b) mit dem in dieser Ausgangs-Position befindlichen Messer wenigstens eine Scheibe von dem Kaliber als Ausgangs-Situation abzutrennen. Vorzugsweise werden die hierbei vorliegenden Aufschneide-Parameter ermittelt, also gemessen oder aus vorgegeben Parametern entnommen.

With regard to the method for automatically positioning the cutting machine during slicing by positioning its knife axis 3' in X and Y directions during slicing operation of the cutting machine, with which strand-shaped product calibers from a food product are to be sliced, it is known

• a) Before starting the slicing operation, set the knife axis in the X and Y directions to a specified starting position. This can be based on empirical values, in particular an empirical value for the X and Y direction setting from a previous order with similar slicing parameters as the new order.
• b) using the knife in this initial position to cut at least one slice from the initial caliber. Preferably, the slicing parameters present in this process are determined, i.e., measured or derived from predefined parameters.

According to the invention, according to step c), during the slicing operation, the knife axis is then moved from the starting position in the X and/or Y direction within a predetermined adjustment range to different measuring positions and at each of the measuring positions at least one slice is cut off.

According to step d), during separation at the individual measuring positions, the load on the rotating knife is measured and, in particular, stored, then together with the respective measuring position, whereby, as explained above, the load in the direction of rotation is primarily measured, preferably measured in the form of the torque of the knife or the knife drive, in particular the knife motor, or the current consumption of the knife motor.

Preferably, the loads are measured at the individual measuring positions in quick succession, in particular immediately one after the other, so that in particular at each measuring position as few slices as possible are cut off which are necessary to measure the load, preferably only one slice, and then the device moves immediately to the next measuring position.

This ensures that the slicing parameters at the cutting edge of the knife change as little as possible, for example due to a change in the consistency of the caliber along the feed direction.

Preferably, a step size is also specified with which the knife axis is adjusted from the starting position to the various measuring positions within the adjustment range.

After the loads have been determined over the adjustment range at least in the Y direction, preferably also in the X direction, over the entire adjustment range, according to step e) the knife axis is automatically set in the slicing operation to such an operating position in the X and Y directions, at or near whose X and/or Y value of a measuring position the load on the knife was the lowest.

• Wenn im Schritt c) die Messerachse von der Ausgangs-Position aus zunächst schrittweise über den gesamten Verstell-Bereich nur in Y-Richtung verstellt wurde und ggfs. anschließend von der Ausgangs-Position aus nur in X-Richtung, so ergibt sich sowohl in der X-Richtung als auch in der Y-Richtung jeweils ein Wert, an dem die Belastung am geringsten war, nämlich aus derjenigen Mess-Position, an der in der jeweiligen Richtung die geringste Belastung gemessen wurde.

There are different ways to do this:

• If in step c) the knife axis was first adjusted step by step from the starting position over the entire adjustment range only in the Y direction and then, if necessary, from the starting position only in the X direction, a value results in both the X direction and the Y direction at which the load was at its lowest, namely from the measuring position at which the lowest load was measured in the respective direction.

These two values can be combined for the setting according to step e) for the further slicing operation to form an X-Y position of the knife axis, i.e. the operating position.

However, since there can be interactions between the X position and the Y position that cannot be predicted, in step c) starting from the starting position, instead of only changing the X position in a first pass and then only the Y position in a second pass, measuring positions in the entire 2-dimensional adjustment range can be approached with the knife axis using the specified step sizes in the X and Y directions and cuts can be made there and the loads can be measured and, if necessary, saved, then again together with the respective measuring position.

Then, from these 2-dimensionally distributed measuring positions, a measuring position results at which the load in step d) was lowest, and this is selected as the operating position.

Furthermore, interpolations between measuring positions may also be necessary, for example because a curve placed through the measuring positions in the load diagram or in the position diagram shows that the lowest value of the curve lies between two measuring positions, both when the measuring positions change in only one transverse direction or in both transverse directions to the knife axis.

Preferably, even after the automatic adjustment, the slicing parameters occurring during the further slicing operation, i.e. with the knife axis in the operating position, are determined, preferably measured or, if known, stored, together with the Z position within the caliber in which the knife was located, which is known from the advance of the feed unit, and/or also the loads on the knife occurring during the further cuts, in particular each further cut.

• - vom Produkt abhängige Produkt-Parameter und/oder
• - von den herzustellenden Scheiben und / oder Portionen abhängige Scheiben-Parameter und/oder
• - von den für diesen Arbeitsauftrag vorgegebenen Maschinen-Einstellungen abhängige Maschinen-Parameter, wobei die entsprechend vorgegebene Maschinen-Einstellung auch direkt ein solcher Maschinen-Parameter sein kann. Konkret kann ein Produkt-Parameter
• - ein die grundsätzliche Art des Produktes, z.B. Hartkäse, Weichkäse, Wurst, luftgetrockneter Schinken etc. angebender Produkt-Parameter sein und/oder
• - ein die Größe, insbesondere die Querschnitts-Abmessungen des Produktes beschreibender Produkt-Parameter und/oder
• - ein die Temperatur, insbesondere die Oberflächentemperatur und/oder die Kerntemperatur, des Produkt-Kalibers beschreibender Produkt-Parameter.

The slicing parameters can include

• - product-dependent product parameters and/or
• - slice parameters depending on the slices and/or portions to be produced and/or
• - Machine parameters dependent on the machine settings specified for this work order, whereby the corresponding machine setting can also be such a machine parameter. Specifically, a product parameter can
• - a product parameter indicating the basic type of product, e.g. hard cheese, soft cheese, sausage, air-dried ham, etc. and/or
• - a product parameter describing the size, in particular the cross-sectional dimensions of the product and/or
• - a product parameter describing the temperature, in particular the surface temperature and/or the core temperature, of the product caliber.

A typical disk parameter can be the disk thickness.

• - die für diesen Arbeitsauftrag vorgegebene zu verwendende Anzahl von Spuren der Aufschneide-Maschine und/oder
• - die hierfür vorgegebene Messer-Drehzahl und/oder
• - die grundsätzliche Art des Messers, insbesondere Sichelmesser oder Kreisscheibenmesser und dabei wiederum konkreter bei einem Sichelmesser die konkrete Form des Sichelmessers und/oder
• - der aktuelle Abnutzungs-Zustand des Messers, beispielsweise angegeben anhand der Anzahl der mit dem Messer bereits durchgeführten Schnitte durch das Kaliber.

Machine parameters can be

• - the number of lanes of the slicing machine to be used for this work order and/or
• - the specified blade speed and/or
• - the basic type of knife, in particular sickle knife or circular disc knife and, more specifically in the case of a sickle knife, the specific shape of the sickle knife and/or
• - the current state of wear of the knife, for example indicated by the number of cuts already made with the knife through the caliber.

As a rule, when the knife cuts through the caliber within this knife revolution, even within its cutting segment in which the sickle knife is engaged in at least one caliber, the load on the knife does not remain constant but fluctuates.

Then, either the maximum value measured during this cut or its arithmetic mean between the maximum value and the minimum value during one revolution of the knife is used as the measured load.

Another possibility is to determine the center of gravity of the area of the curve via its minimum value from the load curve, in particular the torque curve, over a complete revolution of the knife at this cut and to use the resulting load value of this center of gravity as the load at this cut.

An even more differentiated analysis and approach can be achieved by determining the knife load across individual segments of a knife revolution. These rotational position segments can be defined and limited by the rotational position angles at which the knife enters or exits a caliber, for example, and/or at which the knife enters or exits the cutting frame channel.

The cutting frame channel is understood to be the channel whose cross-section corresponds to the circumferential contour of the cutting frame and which extends from the cutting frame in the feed direction of the calibers.

Such rotational position segments are usually directly adjacent to one another in the circumferential direction and preferably cover the entire cutting edge segment, i.e. the segment of the knife within which the circumferential contour is sharply ground as a cutting edge.

In such a segment-by-segment analysis, one possibility is to compare only the rotational position segment and the loads present in the individual measuring positions in which the highest load was determined in the initial position of the knife.

This is based on the idea that the maximum load on the knife during slicing should be reduced.

However, it is also possible that a certain operating position causes a reduction in the load value compared to the initial position within the rotational position segment with the highest load values, but an increase in the load compared to the initial position can be observed in other rotational position segments.

It may then be useful to determine the size of the segment, particularly of these two mentioned rotational position segments, and to determine from the respective product of segment size and the decrease or increase in load that has occurred therein compared to the initial position whether the amount of the decrease product or the increase product is greater.

Depending on this, if the increase product is larger, the selected operating position can be retained, but if the decrease product is larger, the selected operating position and the measurement position on or near which the operating position was located can be discarded and a new operating position can be determined using the described procedures without taking them into account.

Preferably, the adjustment of the knife axis in the slicing operation according to step e) is carried out at least at the beginning of each new batch of calibers to be sliced.

In particular, if one of the slicing parameters, in particular measured ones, differs during the slicing operation by a predetermined absolute or relative difference value from its initial value, as determined during slicing in the initial position of the knife, the knife axis should be adjusted again.

If, when the knife enters or exits the cutting frame channel, the load on the knife changes beyond a specified tolerance value, this also indicates that the knife is contacting the cutting frame during slicing operation, whereupon appropriate countermeasures should be carried out, for example, an automatic increase in the axial distance of the knife and thus the knife plane from the cutting frame.

As a further side effect, irregularities in relation to the slicing machine, for example an incorrect caliber loading of the slicing machine and/or a malfunction of the measuring and/or the knife drive, can be determined from the knife load, in particular the torque around the knife axis measured on the knife drive, preferably the knife motor, and/or the current consumption of the knife motor.

According to one embodiment, if the knife load changes when the rotation angle is incorrect compared to the target caliber, this can be used to conclude that the knife is incorrectly loaded with an actual caliber with an incorrect cross-section and a warning signal can be sent to the operator and/or an automatic stop of the slicing machine can be carried out.

Additionally or alternatively, if the knife load changes too much or too little at a rotation angle compared to the rotation angle expected for a target caliber, this can be used to conclude that the caliber is incorrectly loaded with an actual caliber with the wrong consistency or freezing state and a warning signal can be given to the operator and/or an automatic stop of the slicing machine can be carried out.

Furthermore, if the load on the knife fluctuates too much away from the contact with the caliber, especially during blank cuts or during a revolution away from the cutting segment, it can be concluded that there is a malfunction in the knife, for example a loose knife fastening, and a warning signal is given to the operator and/or an automatic stop of the machine is carried out.

Furthermore, in step b) several, in particular at least three, better at least five, better at least ten, cuts can be carried out, and then it can be checked whether during this time the load on the knife does not decrease by more than a specified load difference, otherwise it can be concluded that there is contamination and the cutting unit can be manually checked for contamination.

According to a further embodiment, the power supply to the knife motor in the slicing mode can be controlled as a function of changes in the rotational speed of the knife during a complete knife revolution. If a specified tolerance difference between the lowest and the highest rotational speed occurring during a complete knife revolution is exceeded, the power supply to the knife motor is increased; if the rotational speed has dropped to an unacceptable level, the power supply is reduced in the opposite case, in each case until the rotational speed is again within the permissible range.

Additionally or alternatively, the power supply to the knife motor in slicing mode can be controlled depending on the deviations of the actual rotation speed from a target rotation speed during a complete knife revolution by increasing the power supply to the knife motor if a specified tolerance deviation is exceeded. if the orbital speed has dropped to an unacceptable level, in the opposite case it is reduced until the orbital speed is again within the permissible range.

• - einem Grundgestell,
• - einem um eine Messerachse mittels eines Messer-Motors rotierend antreibbaren Messer, welches eine Schneidkante aufweist,
• - einer Gegenkante zur Schneidkante, die vorzugsweise an einer vorderen Kaliber-Führung, etwa dem Schneidrahmen für das aufzuschneidende Kaliber ausgebildet ist,
• - einer Verstell-Vorrichtung zum Verstellen des Messers mit der Messerachse und damit der Position des Messers quer zur Richtung der Messerachse, insbesondere auch des Messers entlang der Messerachse,
• - einer Steuerung zum Ansteuern der Verstell-Vorrichtung sowie des Messer-Motors wird die bestehende Aufgabe erfindungsgemäß dadurch gelöst, dass
• - ein Belastungs-Sensor zum Messen der Belastung des Messers vorhanden ist und die Steuerung der Maschine so ausgebildet ist, dass sie in der Lage ist, das zuvor beschriebene Verfahren durchzuführen.

Regarding a generic slicing machine with

• - a base frame,
• - a knife which can be driven in rotation around a knife axis by means of a knife motor and which has a cutting edge,
• - a counter edge to the cutting edge, which is preferably formed on a front caliber guide, such as the cutting frame for the caliber to be cut,
• - an adjustment device for adjusting the knife with the knife axis and thus the position of the knife transverse to the direction of the knife axis, in particular also the position of the knife along the knife axis,
• - a control for controlling the adjustment device and the knife motor, the existing object is achieved according to the invention in that
• - a load sensor is provided to measure the load on the knife and the control system of the machine is designed to be able to carry out the process described above.

The load sensor can be a torque sensor on the knife or the knife drive, in particular the knife motor, or a current sensor on the knife motor that measures the strength of the current consumed during slicing.

Preferably, the machine is provided with a rotation angle sensor which is capable of determining the rotational position of the knife during the slicing operation, in particular within one revolution of a plurality of revolutions.

c) Examples of implementation

• 1a: eine Aufschneide-Maschine in Form eines Slicers gemäß dem Stand der Technik in perspektivischer Ansicht,
• 1b: in der Seitenansicht einen vereinfachten vertikalen Längsschnitt durch die Aufschneide-Maschine der 1a, in dem die verschiedenen Förderbänder besser zu erkennen sind, da die in Blickrichtung davorliegenden Abdeckungs- und Verkleidungsteile vor der Schnittebene liegen, mit in die Aufschneidestellung hochgeklapptem Zufuhrband,
• 2: in der Seitenansicht der 1b, aber demgegenüber vergrößert, das Abtrennen von Scheiben,
• 3a, b: Diagramme, welche die Belastung des Messers in Abhängigkeit von der Y-Position des Messers darstellen,
• 3c: ein Diagramm mit der Verteilung der Mess-Positionen in X-und Y-Richtung,
• 4a - g: unterschiedliche Drehlagen des Messers zum Schneidrahmen betrachtet in axialer Richtung,
• 5a: ein Drehmoment-Diagramm in Abhängigkeit dieser Drehlagen,
• 5b: ein Geschwindigkeits-Diagramm, und
• 6a, b: unterschiedliche Stellungen der Schneidebene zum Schneidrahmen in der Seitenansicht.

Embodiments according to the invention are described in more detail below by way of example. They show:

• 1a : a slicing machine in the form of a slicer according to the prior art in perspective view,
• 1b : in side view a simplified vertical longitudinal section through the slicing machine of the 1a , in which the various conveyor belts are easier to see, since the cover and cladding parts in front of them are in front of the cutting plane, with the feed belt folded up into the cutting position,
• 2 : in the side view of the 1b , but in contrast, enlarged, the cutting of slices,
• 3a , b: Diagrams showing the load on the knife as a function of the Y-position of the knife,
• 3c : a diagram with the distribution of the measuring positions in X and Y directions,
• 4a - g: different rotational positions of the knife relative to the cutting frame viewed in axial direction,
• 5a : a torque diagram depending on these rotational positions,
• 5b : a speed diagram, and
• 6a , b: different positions of the cutting plane to the cutting frame in the side view.

The 1a shows a perspective view of a slicing machine 1 in the form of a slicer 1 for the simultaneous slicing of several product calibers K next to each other and, if necessary, depositing in shingled portions P each consisting of several slices S - see 2 - with a general horizontal direction of passage 10* of the material to be cut through the slicer 1 from right to left.

1b shows a vertical section through such a slicer 1 - simplified by omitting details less important for the invention - cut in the longitudinal direction 10, the feed direction of the calibers K to the cutting unit 7 and thus the longitudinal direction of the calibers K located in the slicer 1, and thus also cut in the general throughput direction 10*.

The basic structure of a slicer 1 according to the prior art consists in that a cutting unit 7 with a sickle knife 3 driven in rotation about a knife axis 3' by a knife motor 22, several, in this case four, adjacent transversely to the feed direction 10, in 1a not shown, product caliber K are fed from a feed unit 20, from the front ends of which the rotating sickle knife 3 simultaneously cuts off a slice S.

For this purpose, the feed unit 20 comprises a feed conveyor 4 in the form of an endless, circulating feed belt 4, wherein the calibers K lying next to one another in the width of this feed conveyor 4 in this transverse direction 11 by elevations 15 which protrude outwards from the feed belt 4.

For cutting the product caliber K, the feed conveyor 4 is located in the 1a , b shown inclined position with low-lying cutting-side, front end and high-lying rear end - the slicing position - from which it can be folded down relative to the base frame 2 of the slicing machine 1 about a pivot axis 4' running in the first transverse direction 11, which is located near the cutting unit 7, into an approximately horizontal loading position in which new product calibers K are already placed on the feed conveyor 4, while the remainder KR of the previous calibers K are still held on the gripper 14 and between the upper and lower product guides 8, 9 and are fully sliced.

The rear end of each caliber K located in the feed unit 20 - see 1b - is held by a gripper 14a - d in a form-fitting manner with the aid of gripper claws 16.

These activatable and deactivatable grippers 14a - 14d are attached to a common gripper unit 13, which can be guided in a controlled manner along a rod-shaped gripper guide 18 in the feed direction 10, whereby, however, the actual feed speed of the calibers K is effected by a so-called upper and lower product guide 8, 9, which each consist of an endless, circulating guide belt and which engage the top and bottom of the calibers K to be cut at their front end areas near the cutting unit 7, whereby all moving parts of the machine 1 are controlled by its control system 1*.

For slicing, the front ends of the calibers K are each guided through a so-called product opening 6a - d which is provided for each caliber and is formed in a plate-shaped cutting frame 5, wherein the cutting plane 3" runs directly in front of the front, diagonally downward facing end face of the cutting frame 5, in which cutting plane the sickle knife 3 rotates with its cutting edge 3a and thus separates the excess of the calibers K from the cutting frame 5 as slices S. The cutting plane 3" runs perpendicular to the upper run of the feed conveyor 4 and/or is spanned by the two transverse directions 11, 12.

A load sensor 24 arranged on the knife drive (see for example 1b) measures the knife load MB present on the knife drive or on the knife 3 itself.

The upper product guide 8 is displaceable in the second transverse direction 12—which runs perpendicular to the surface of the upper run of the feed conveyor 4 folded up into the slicing position—to adapt to the height H of the caliber K in this direction, which can be determined by a height sensor 19. Furthermore, at least one of the product guides 8, 9 can be pivotable about one of its deflection rollers 8a, 8b, 9a, 9b in order to be able to change the direction of the run of its conveyor belt adjacent to the caliber K to a limited extent.

The slices S, which are positioned at an angle in space according to the inclination of the feed unit 20 and the cutting plane 3", fall - see 2 - to a discharge unit 17 beginning below the cutting frames 5 and running in the direction of travel 10*, which in this case consists of several discharge conveyors 17a, b, c arranged one behind the other with their upper strands approximately aligned in the direction of travel 10*, one of which can also be designed as a weighing unit.

Below the feed unit 20 there is also an approximately horizontally running residue conveyor 21, which begins with its front end below the cutting frame 5 and immediately below and/or behind the discharge unit 17 and with its upper run transports residues falling onto it backwards from there against the throughput direction 10*.

For this purpose, at least the first discharge conveyor 17a in the throughput direction 10* can be driven with its upper run counter to the throughput direction 10*, so that a remaining piece KR falling onto it, for example, can be transported backwards and falls onto the lower-lying remainder conveyor 21.

After separation, the slices S fall either directly onto these conveyors 17a - c, as in 1b shown, or, as in 2 shown, onto a packaging element V placed thereon, such as a carrier carton or a flat plastic tray.

The 3a -c show the procedure for determining the optimal knife position with the lowest knife load.

3a shows a single load diagram in which the measured knife load MB is visible both for the starting position AP and for different measuring positions MP(0/1) - MP(0/7), preferably further away from it by the Y increment SW-Y. These measuring positions thus differ from the starting position AP only in their Y value, but whose X position is the same as for the starting position AP. The measuring positions preferably cover the entire adjustment range 27-Y in the Y direction.

Of these, the measuring positions MP(0/1) to MP(0/3) are located to the left of the starting position AP, so they have a lower Y value, while the others have a higher Y value.

• Entweder man betrachtet nur die Messer-Belastungen an den einzelnen Mess-Positionen. Dann stellt man fest, dass an der Mess-Position MP(0/4) die Belastung des Messers die geringste war, also MP(0/4) = MPmin, und auch geringfügig kleiner als an der Ausgangs-Position. Der Fachmann könnte dann den Y-Wert der Messerachse 3' von der Ausgangs-Position aus auf den Y-Wert der Mess-Position MP (0/4) also der Messer-Position MPmin mit der geringsten Messer-Belastung verstellen für den weiteren Aufschneide-Betrieb.

If the knife position is to be optimized only with regard to the Y-direction, these measured values can still be handled in two ways:

• Either one considers only the knife loads at the individual measuring positions. Then one determines that the knife load was lowest at the measuring position MP(0/4), i.e., MP(0/4) = MPmin, and also slightly lower than at the starting position. The specialist could then adjust the Y value of the knife axis 3' from the starting position to the Y value of the measuring position MP(0/4), i.e., the knife position MPmin with the lowest knife load, for further slicing operations.

Alternatively, a more precise determination of the optimal Y position can be performed. This can be achieved by plotting a curve through all available measurement positions MP(0/1) - MP(0/7), including the starting position AP, where the load was also measured, and determining the lowest point Pmin of this curve, i.e., the point with the lowest knife load. The expert would then change the position of the knife axis 3' from the starting position AP to the Y value of Pmin.

If an optimization of the position of the knife axis in the X-direction is desired, the knife axis 3' in the X-direction would be reduced from the starting position AP step by step preferably always by the same X-step width SW-X - in this case four times - and also increased - in this case also four times - and for each of the X-positions according to 3a with lower and higher Y-value, set measuring positions MP (.../1) to MP (.../7) and do this for all X-values and thereby the 3b The set of curves shown with the load curves MB (1/Y) to MB (8/Y) is obtained in addition to the load curve MB (AP/Y), which was determined with an X value of the knife axis 3' corresponding to the starting position.

In 3b For each load curve, the minimum load value Pmin1 - Pmin8 - already interpolated between measuring positions of this load curve - is visible and plotted, which in this case all lie on a straight line running obliquely to the axis of the load value MB, although this does not have to be the case.

Furthermore, the family of curves shows that these lowest load values Pmin1 - Pmin8, as well as the load curves on which they lie, increasingly deviate from the initial load curve MB(AP/Y) with increasing X-value deviations, both with increasing and decreasing X-values. Qualitatively, however, the individual load curves have essentially the same shape.

Above all, the family of curves shows that in this case the lowest load value across all load curves is Pmin1, i.e. the minimum load value on the load curve MB(1/Y), i.e. the load curve that was determined at the lowest X-value of its measuring positions.

The expert would therefore take the lowest load value from this set of curves, which is at Pmin1, and the knife axis 3' would be aligned both on the 3b visible Y-value as well as the X-value with which this load curve MB(1/Y) was determined.

The same situation as 3b shows 3c , but in an XY diagram in which the individual measuring positions MP (1/1) to MP (8/7) are marked, at which load measurements were carried out.

Accordingly, the X values are spaced apart by the same X increment SW-X, and the Y values of the measurement positions MP are spaced apart by the same Y increment SW-Y, as mentioned above. However, the two increments do not have to match. The increments are usually specified and also depend on the adjustment range in both directions, i.e., 27-Y and 27-X.

The amount of the respective charge is the one in 3c invisible third dimension, i.e. in the direction of view of the 3c , and thus results in a 3-dimensional structure, whose section along the line MP (1/...), e.g. the load curve MB(1/Y) from 3b and whose section along the X-position MP (8/...) gives the load curve MB(8/Y) from 3b is.

This leads 3c Of course, to the same result, namely that when creating a 3-dimensional curved surface that contains all measuring positions MP, the lowest point Pminmin of this three-dimensional curved surface has the X and Y value at which the knife load MB is the lowest, so that for the further slicing operation the knife axis 3' on the X and Y-value of this lowest point should be set to Pminmin.

This point is according to 3b on or near the X and Y values of the measuring position MP(1/4), but can deviate slightly from this in the X direction due to the interpolating effect of the 3-dimensional curved surface, but only upwards, since the load curve is the last, lowest of the family of curves, but is also slightly offset in the Y direction from the measuring position MP(1/4) in the direction of MP(1/5), as can be seen from 3b visible.

However, the knife load MB also varies during a single cut, i.e. a single rotation of the knife when cutting a slice S.

In the 4a to 4g is a sickle knife 3 used in this case in different rotational positions - which are detected by a rotational position sensor 26 - about its rotational axis 3', the Z-direction, shown when separating a disc S from the in this case only two calibers K1 and K2 arranged next to each other and cut open simultaneously by the knife 3.

The position of the rotation axis 3' and thus of the entire knife 3 can be controlled by means of an adjusting device 23 in the X and Y directions relative to the cutting frame 5.

The cutting edge 3a approaching from above in this illustration penetrates in the axial direction 10 according to 4a initially from a rotation angle α5A - measured from the penetration direction 25 of the knife 3, which in this case still has a negative value - into the upper side 5b of the cutting frame channel 5*, which extends from the illustrated cutting frame 5 towards the viewer of this 4a extends.

The angle of rotation α is the angle of the immersion direction 25 - the perpendicular from the knife axis 3' to the upper side 5b of the cutting frame channel 5* in the knife plane 3" - to a radial reference line 27, namely the radial beam in the knife plane 3" from the knife axis 3' to the beginning of the cutting edge 3a, at which the latter has the smallest distance to the knife axis 3'.

Normally, the knife 3 should maintain a small axial distance, the cutting gap 100, in the axial direction to the front surface of the cutting frame 5, as shown in the side view of the 6a visible.

Upon further rotation of the sickle blade 3, its cutting edge 3a reaches 4b for the first time the cross-section of the first of the product openings 6.1, and thus the caliber K1 located therein, at a rotation angle αK1A.

Upon further rotation, the cutting edge 3a initially reaches 4c the cross-section of the second of the product openings 6.2, and thus the caliber K2 located therein, at a rotation angle αK2A.

Upon further rotation, the cutting edge 3a initially reaches 4d the underside 5c and thus for the first time the end of the cutting frame channel 5* at a rotation angle α5E.

After further rotation, according to 4e the cutting edge 3a from the cross-sectional channel of the first product opening 6b in the direction of rotation of the knife 3 and thus as the cross-section of the first caliber K1, whereby this order can also be reversed depending on the size ratios and design of the cross-section of the product openings 6.1 and 6.2 and of the knife 3.

At the latest shortly before reaching the rotational position according to 4d the peripheral edge of this product opening 6.1 acts as a counter edge 5a to the cutting edge 3a, as in 6a and 4d shown.

As in 4f As shown, the cutting edge 3a then emerges from the cross section of the last product opening 6.2 in the direction of rotation of the knife 3 at an exit angle αK2E, and thus from the caliber K2 accommodated therein, and here too, before reaching this rotational position, the peripheral edge of this product opening 6.2 acts as a counter edge 5a to the cutting edge 3a.

The intermediate angle between αK1A and αK2E thus represents the cutting segment αK1A-αK2E.

As in 4g As shown, the cutting edge 3a then emerges from the cross section of the cutting frame channel 5* at an exit angle α5E.2 upon further rotation.

• Am Beginn der Umdrehung sollte das Messer 3 bis zum Eintritt in den Querschnitt des ersten Kalibers 6.1 beim Drehlagen-Winkel αK1A keine Berührung weder mit diesem Kaliber 6.1 noch dem Schneidrahmen 5 haben und bis dahin im Leerlauf-Drehmoment, also mit der Leerlauf-Belastung MB-L, drehen.

The 5a shows how this can affect the knife load MB of knife 3 within one full rotation of knife 3:

• At the beginning of the rotation, the knife 3 should not have any contact with this caliber 6.1 or the cutting frame 5 until it enters the cross section of the first caliber 6.1 at the rotation angle αK1A and should rotate until then at the idle torque, i.e. with the idle load MB-L.

From the moment the cutting edge 3a penetrates the cross-section of the first caliber K1 at αK1A, the knife 3 suddenly experiences an increased resistance and is subject to a load which is higher than the no-load load MB-L, which increases slightly with increasing penetration of the knife 3 into the cross-section of this caliber K1 due to the increasing contact surface between the knife and caliber K6.1 on the back of the knife 3 and the disc S which has already been partially separated from it on the front of the knife 3.

As shown, even within such segments the load always fluctuates slightly due to other factors, which is why a horizontal wavy line is drawn as the load curve for the no-load load MB-L, and likewise a mostly non-horizontal wavy line is drawn in all other rotational position segments.

From the angle of rotation αK2A, the knife 3 also dips into the adjacent second caliber K6.2, which in turn causes a sudden increase in the knife load MB at αK2A, whereby from then on until the knife 3 exits the first caliber 6.1 at the angle of rotation αK1E, the knife load MB increases substantially and usually reaches its maximum value MBmax at αK1E.

As mentioned above, either this maximum value MBmax could be used as the knife load MB for this cut or another value derived from the load curve of this cut, for example the average knife load MBØ within the cutting segment, either in the form of the arithmetic mean between the idle load MB-L and the maximum value MBmax or in the form of the center of gravity of the area between the idle load MB-L and the MB curve above.

In the last part of this segment, the knife load MB could possibly decrease if the load decrease due to the decreasing contact area with the caliber K6.1 is greater than the load increase due to the increasing contact area with the second caliber 6.2.

When the cutting edge 3a exits the cross-section of the first caliber 6.1 at αK1E, the knife load MB drops suddenly.

Since from this angle of rotation the contact area of the knife 3 to the second caliber 6.2 remains essentially the same, from here on the knife load MB is initially approximately constant and then decreases until the cutting edge 3a exits the second caliber 6.2 at αK2E due to the decreasing contact area of the knife 3 to the caliber 6.2 on the one hand and the disk S which has already been largely separated from it on the other hand, normally up to the idle load MB-L, at which the knife load MB remains until the end of the revolution.

When cutting off a disc S, the cutting edge 3a runs at a small, constant distance, which is 6a drawn cutting gap 100, along the front surface 5.1 of the cutting frame 5 facing the knife 3, since the knife plane 3" defined by the cutting edge 3a lies parallel to the front surface 5.1 of the cutting frame 5. As a rule, the knife 3 is flat in that its cutting edge 3a defines a knife plane 3".

The peripheral edge of the product opening 6 on the front side 5.1 of the cutting frame 5 acts as a counter edge 5a for the cutting edge 3a, at least over part of the circumference of the product opening 6.

The cutting gap 100 is necessary above all so that the knife 3 with its cutting edge 3a does not slide along the front surface 5.1 of the cutting frame 5 with each cut, since this would, on the one hand, cause the cutting edge 3a to become blunt very quickly and, on the other hand, damage the front surface 5.1 and in particular the counter edge of the cutting frame 5.

On the other hand, a cutting gap 100 that is too large prevents a sufficient effect of the counter edge 5a on the cutting edge 3a and worsens the cutting result.

However, if these two surfaces are not parallel to each other in both transverse directions X and Y - i.e., if they are more than a tolerance angle ß to be defined - then a constant cutting gap 100 cannot be set over the complete rotation of the knife 3, so that the slices S produced have a different thickness in their different cross-sectional areas, and the parallelism of the cutting plane 3" to the front surface 5.1 of the cutting frame 5 should first be restored, for example by the operator adjusting this front surface 5.1 in its spatial position parallel to the cutting plane 3".

• Denn dann erhöht sich die Messer-Belastung MB von der Leerlauf-Belastung MB-L aus bereits bei Eintritt der Schneidkante 3a in den Schneiderahmen-Kanal 5* bei α5A ein erstes Mal, und von da ab analog weiter entsprechend der Eintritte in und Austritte aus den einzelnen Kalibern und sinkt erst beim endgültigen Austritt der Schneidkante 3a aus dem Schneiderahmen-Kanal 5* bei α5E2 zurück auf die der Leerlauf-Belastung MB-L.

Grinds the cutting edge 3a of the knife 3, - for example due to non-parallelism of the cutting plane 3" to the front surface 5.1 of the cutting frame 5 - as for example in 6b shown, this is usually done using the load diagram according to 5a for the operator or automatically by the control system, as shown there with straight lines instead of wavy lines:

• Because then the knife load MB increases from the idle load MB-L already when the cutting edge 3a enters the Cutting frame channel 5* at α5A for the first time, and from then on analogously according to the entries into and exits from the individual calibers and only drops back to the idle load MB-L at the final exit of the cutting edge 3a from the cutting frame channel 5* at α5E2.

If the cutting edge 3a already exits the cutting frame channel 5* at another point, for example at α5E1, here shortly before αK1E, a first reduction in the knife load MB can already occur there.

5b shows the possible fluctuation range δv of the rotational speed v of the idle knife 3 during one complete revolution, so that the actual rotational speed Ist-v mostly oscillates around the desired target rotational speed Soll-v and the knife motor 22 is controlled depending on this during speed control.

If the relative fluctuations δv are greater than a specified tolerance difference δvD, the current supply is increased during speed control if the rotational speed v has dropped to an unacceptable level, and reduced in the opposite case, until the rotational speed is again within the permissible range.

If the absolute deviations from the target rotational speed Soll-v are greater than a specified tolerance deviation Tol-δv, the current supply is increased during speed control if the rotational speed has dropped to an unacceptable level, and reduced in the opposite case, until the rotational speed v is again within the permissible range.

LIST OF REFERENCE SYMBOLS

1

Slicing machine, slicer

1*

steering

2

Base frame

3

Knife

3'

Knife axis

3''

Knife plane, cutting plane

3a

cutting edge

4

Feed conveyor, feed belt

4'

Swivel axis

5

Caliber guide, cutting frame

5.1

Front surface

5a

Counter edge

6, 6a - d

Product opening

7

Cutting unit

8

upper product guide

8a, b

pulley

9

lower product guide

9a, b

pulley

10

axial direction, feed direction

10a

Approach direction

10b

Spacing direction

11

first cross direction (width slicer)

12

second transverse direction (height direction caliber)

13

Gripper unit, gripper carriage

14:14a-d

gripper

15

Survey

16

Gripper claw

17

Discharge unit

17a, b, c

Portioning belt, discharge conveyor

18

Gripper guide

19

Altitude sensor

20

Feed unit

21

Remnant conveyor

22

Knife motor

23

adjustment device

24

Load sensor

25

Immersion direction

26

Rotation position sensor

27

Adjustment range

100

Cutting gap

α

Rotation angle of the knife ...

α5A

... when the cutting edge enters the cutting frame area

α5E

... when the cutting edge exits the cutting frame area

αK1A

... when the cutting edge enters caliber K1

αK1E

... when the cutting edge exits caliber K1

αK1A - αK2E

Rotational position segment

β

Difference angle

AP

Starting position

BP

Operating position

MP1/1

Measuring position

K

Caliber, product caliber

MB

Knife load

MB-L

Blade load at idle

MD1

first moment difference

MD2

second moment difference

MBmax

maximum blade load achieved within one revolution

MBØ

average blade load within one revolution

S

disc

V

Packaging element

v

Orbital speed

δv

Fluctuation range, change

δvD

Tolerance difference of the orbital speed

Tol-δv

Tolerance deviation of the orbital speed

Claims (15)

Method for automatically positioning the knife axis (3') running in the Z direction of a rotatingly driven knife (3) in the X and/or Y direction during the slicing operation of a slicing machine (1) for slicing strand-shaped product calibers (K) from a food product into slices (S), by the method steps a) before the start of the slicing operation, setting the knife axis (3') in the X and Y directions to a starting position, which is predetermined in particular as a function of the slicing parameters present for this order, b) separating at least one slice (S) from the caliber (K) with the knife (3) in the starting position as the starting situation, and in particular measuring the knife load (MB) and in particular slicing parameters in this starting situation, characterized by c) during the slicing operation, displacing the knife axis (3') from the starting position in the X and/or Y direction to different measuring positions (MP), in particular in quick succession, in particular within a predetermined adjustment range (27), d) during the slicing operation, measuring the knife load (MB) of the rotating knife (3) at least in the direction of rotation (U) at the different measuring positions (MP), e) during the slicing operation, adjusting the knife axis (3') in the X and Y directions to an operating position at whose X and/or Y value of a measuring position (MP) the load was the lowest. Procedure according to Claim 1 , characterized in that the torque about the knife axis (3') and/or the current consumption of the knife motor (22) measured on the knife (3) or its knife drive, in particular the knife motor (22), is used as a measure for the load (MB) of the knife (3). Method according to one of the preceding claims, characterized in that - the operating position (BP) is one of the measuring positions (MP) or is a position interpolated with respect to the X and/or Y value between several measuring positions (MP). Method according to one of the preceding claims, characterized in that - during the slicing operation, slicing parameters are determined, in particular measured, and stored together with the operating position (BP) of the knife (3), - in particular for determining the starting position (AP) of the knife (3) for subsequent batches of similar calibers (K). Method according to one of the preceding claims, characterized in that the slicing parameters comprise: - product parameters dependent on the product caliber and/or - slice parameters dependent on the slices to be produced and/or - machine parameters dependent on the machine settings specified for this work order. Method according to one of the preceding claims, characterized in that , in the case of a varying load (MB) of the knife (3) measured within one revolution of the knife (3), its maximum value (MBmax) or its mean value (MBØ), for example in the form of the arithmetic mean value between its maximum value (MBmax) and the no-load load (MB-L) or in the form of the center of gravity of the area between between the load curve and the no-load load (MB-L), in the cutting segment of this one revolution is used as the knife load (MB). Method according to one of the preceding claims, characterized in that - the knife load (MB) of the knife (3) is determined for individual rotational position segments of the knife (3) within a full revolution, - in particular for the rotational position segments of the knife (3) by rotational position angles (α) which correspond to the entry or exit of the knife (3) into one of the simultaneously cut product calibers (K1, K2) and/or the entry or exit of the knife (3) into the cutting frame channel (5*) and/or - in particular the rotational position segments directly adjoin one another and in particular cover the entire cutting edge segment. Method according to one of the preceding claims, characterized in that only that rotational position segment is taken into account in which the highest knife load (MB) was determined in the starting position (AP) of the knife (3). Method according to one of the preceding claims, characterized in that the adjustment of the knife axis (3') - takes place at least at the beginning of each new batch of calibers (K), - in particular additionally if one of the slicing parameters differs during the slicing operation by a predetermined absolute or relative difference value from its initial value which existed when cutting with the knife (3) in its initial position (AP). Method according to one of the preceding claims, characterized in that - in the event of a change in the knife load (MB) of the knife (3) above a predetermined tolerance value when the knife (3) enters or exits the cutting frame channel (5*), this is evaluated as an indication of contact with the cutting frame (5) by the knife (3) during slicing operation and corresponding countermeasures are carried out, - in particular an automatic increase in the axial distance of the knife plane (3") from the cutting frame (5) is carried out, and/or - in the event of a change in the knife load (MB) with an incorrect rotational angle (α) compared to a target caliber, this is inferred to indicate incorrect caliber loading, in particular with an actual caliber with an incorrect cross-section, and a warning signal is given to the operator and/or an automatic stop of the slicing machine (1) is carried out, and/or - in the event of an excessive or insufficient change in the knife load (MB) during a Rotation angle (α) of the rotation angle (a) to be expected for a target caliber, from this it is concluded that there is an incorrect loading with an actual caliber with the wrong consistency or freezing state and a warning signal is given to the operator and/or an automatic stop of the slicing machine (1) is carried out, and/or - in the event of an excessive fluctuation in the knife load (MB) away from the contact with the product caliber (K), in particular during empty cuts or during a revolution away from the cutting segment, it is concluded that there is a fault in the knife (3) and a warning signal is given to the operator and/or an automatic stop of the slicing machine (1) is carried out. Method according to one of the preceding claims, characterized in that in step b) - several, in particular at least three, better at least five, better at least ten, cuts are carried out, - it is checked whether during this time the load (MB) of the knife (3) does not decrease by more than a specified load difference, - otherwise it is concluded that there is contamination and the cutting unit (7) is manually checked for contamination. Method according to one of the preceding claims, characterized in that - the power supply to the knife motor (22) in the slicing operation is controlled as a function of occurring changes (δv) in the rotational speed (v) of the knife (3) during one complete knife revolution, in that - if a specified tolerance difference (δvD) between the lowest and the highest occurring rotational speed during one complete knife revolution is exceeded, the power supply to the knife motor (22) is increased, if the rotational speed has dropped to an unacceptable extent, in the opposite case it is reduced, in each case until the rotational speed is again within the permissible range and/or - the power supply to the knife motor (22) in the slicing operation is controlled as a function of occurring deviations (δv) of the actual rotational speed (Ist-v) from a target rotational speed (Soll-v) during one complete knife revolution, in that - if a specified tolerance deviation (Tol-δv) is exceeded, the power supply to the knife motor (22) is increased when the orbital speed has dropped to an unacceptable level, in the opposite in the opposite case, until the orbital speed is again within the permissible range. Slicing machine (1) with - a base frame (2), - a knife (3) which can be driven to rotate about a knife axis (3') by means of a knife motor (22) and which has a cutting edge (3a), - a counter edge (5a), in particular designed on a front caliber guide (5), in particular a cutting frame (5), for the product caliber (K) to be sliced, - an adjusting device (23) for adjusting the knife (3) transversely to the direction of the knife axis (3'), - a controller (1*) for controlling the adjusting device (23) and the knife motor (22), characterized in that - a load sensor (24) is provided for measuring the load on the knife (3), - the controller (1*) is designed such that it is able to carry out the method according to one of the preceding claims. Slicing machine according to Claim 13 , characterized in that - a rotation angle sensor (26) is provided for determining the rotational position of the knife (3), - the rotation angle sensor is able to determine the rotation angle of the knife (3) within one revolution. Slicing machine according to Claim 13 or 14 , characterized in that - viewed in the axial direction (10), the contour of the peripheral edge of the knife (3) is shaped and dimensioned in such a way and the axis of rotation (3') of the knife (3) to the cutting frame (5) is arranged in such a way, in particular at such a transverse distance to the cutting frame (5), that of a full 360° revolution of the knife (3), this is between 1/4 and 1/3 of a full revolution without overlap with the cutting frame (5) and/or - the largest radius of the knife (3) is between 300 mm and 600 mm.

Images