Patent Application
20220153531
This application claims priority to German Patent Application No. DE 10 2020 130 342.4 filed on Nov. 17, 2020, the disclosure of which is incorporated in its entirety by reference herein.
The invention relates to slicing machines, in particular so-called slicers, which are used in the food industry to slice strands of an only slightly compressible product such as sausage or cheese, and in particular to their discharge unit, by means of which the sliced slices or shingled or stacked portions assembled therefrom are discharged from the cutting unit.
Since these strands can be produced with a cross section that is well shaped and dimensionally stable over their length, i.e., essentially constant, they are called product calibers or just calibers. For the purposes of the present application, however, the term caliber is intended to cover both such strands with a constant cross section over their length and those with a non-constant cross section.
In most cases, several product calibers are cut simultaneously in several tracks next to each other by cutting one slice each at a time from the same blade, which moves in a cross direction to the longitudinal direction of the product calibers.
The product calibers are pushed forward by a feed conveyor in the direction to a cutting unit and its blade, usually on an slanted downwardly directed feed conveyor, and are guided in each case through the product openings of a so-called cutting frame, at the front end of which the part of the product caliber protruding beyond this is cut off as a slice by the blade directly in front of the cutting frame.
The articles, i.e., individual slices or portions, generally fall onto a discharge unit by means of which they are transported away from the cutting unit and from there are usually transferred to a further conveyor which transports the articles to the next processing station, often an insertion machine for inserting the articles into the cavity of a thermoforming belt or individual trays.
Since the articles must have a correct rotational position as seen from above—unless they are individual round slices—as well as a correct transverse position in order to be completely positioned in the cavity, it is known to correct the position of the articles if necessary.
The later such a detection takes place in the passage direction, the better the optical accessibility for a camera, but the correction can also only be carried out at a correspondingly late stage, which undesirably increases the overall length of the machine because of an additional conveyor that may be required for this purpose.
For this purpose, it is first necessary to detect the actual position of the articles, which is possible, for example, in a non-contact manner by means of a camera, in particular a digital camera, directed at the discharge conveyor unit from above. This is known, for example, from WO 2004/000512 A1, which is coupled to the control of the machine referring their signals for controlling the moving parts of the machine.
In this context, a camera is to be understood as any unit operating without a guide, in particular an optical unit, which is possible to determine the actual position of the articles on a support surface, in particular a conveyor.
The upstream, first belt of the discharge unit, the so-called portioning belt, is very short in order to keep its mass low, since it must be intermittently accelerated and decelerated very quickly between the impact of the slice of a portion.
In addition, in some machines, each belt of the discharge unit, for example the portioning belt, comprises several individual belts lying next to each other in the transverse direction, which can be individually controlled, in order to be able to control the slicing on the individual tracks individually.
In this context, a belt or conveyor is to be understood as any type of conveyor in which the articles are moved lying on a movable support surface by the movement of this support surface, being an endless conveyor belt of a belt conveyor deflected around at least two deflecting rollers, or instead many endless conveyor straps of a strap conveyor lying at a small transverse distance from one another, or individual slides that can be moved in particular independently of one another, or other types of conveyors.
It is therefore the object of the invention to provide a method which solves this problem without increasing the overall length of the slicing machine and to provide a slicing machine, in particular a slicer, which is capable of carrying out this method.
With regard to the method, this object is solved in that the actual position of the article on the discharge unit is not only detected, preferably without contact, for example optically by means of a camera, but subsequently this actual position is also automatically compared with a predetermined target position and, in the event of an unacceptably high deviation from the target position, is automatically shifted to the target position, specifically by means of the part, in particular the conveyor of the discharge unit, on which the article rests.
As a result, the article has its target position at the end of the discharge unit at the latest, so that downstream of the discharge unit—regardless of whether this is an independent unit or part of the slicing machine—further conveyors are only required to move the articles to the next processing station, but no conveyors that can additionally perform a position change.
This keeps the length of the slicing machine low up to and including reaching the correct actual position of the articles.
Preferably, for the same reason, the actual position of the article is carried out, if required, either directly on the belt on which the detection of its actual position was also carried out, i.e., the detection belt, or on the belt or conveyor downstream thereof, and in particular immediately downstream thereof. This also promotes the reduction of the underlying.
It should be taken into account that in most cases one of the conveyors of the discharge unit is a weighing conveyor, and a weighing conveyor should generally not be used to change the actual position of the article lying on it in the transverse direction.
Thus, if a discharge unit comprises only three conveyors, namely a portioning belt, a discharge belt and a transfer belt to the next assembly, the target position can still be achieved within the discharge unit despite this embodiment of the second belt immediately following the portioning belt, the discharge belt, as a weighing belt, in that at least the transfer belt following the weighing belt is embodied as a displacement belt for displacing the article from the actual position to the target position, at least in the transverse direction.
To achieve this, it is advantageous to carry out the detection of the actual position as far upstream as possible, preferably directly on the portioning belt. The position correction can then be carried out either on the immediately following second belt, if this is not a weighing belt, or on the third belt, if the second belt is a weighing belt.
Due to the inclination of the portioning belt towards the overhanging cutting frame, it may be difficult for a camera to view it.
Depending on the job and the inclined position of the portioning belt or in general, it may therefore be better to detect the actual position on the second belt, i.e., the belt after the portioning belt, especially if this is a weighing belt, because then this belt and thus the article thereon is generally stationary for a short time for the purpose of weighing, so that during this standstill a particularly accurate detection of the actual position in the transverse direction and/or with regard to the rotational position viewed in the top view is possible. Then, however, the position correction should be carried out on the immediately following then third and often also last belt of the discharge unit.
If the actual position is to be determined, for example by means of a camera, either on the first belt or on the second belt, then either two cameras are required, and it must be possible to switch from one to the other, or instead a switchable deflecting mirror is required in the beam path between the camera, in particular the only camera, and the discharge unit.
Since detection of the actual position on the portioning belt is also difficult because, on the one hand, the portioning belt can oscillate until the last slice of a portion hits it and, on the other hand, moving parts such as the approaching slice can reach into the beam path of the camera until the last slice is deposited, it can be useful to carry out the scanning, in particular optical scanning, not from above but from below.
This can be achieved, for example, with the aid of a transparent belt and a camera positioned under the upper run, preferably between the upper run and the lower run of the positioning belt, whereby a so-called line scanner is also well suited for this purpose, whose light-receiving surface is very long and narrow, in particular only one pixel width narrow, and can extend with its main direction of extension transversely under the upper run of the positioning belt.
All these solutions allow a reliable detection of the actual position and a position correction before the end of the discharge conveyor.
Often the actual position of the article is not in the target position with regard to the rotational position viewed from the top.
Then the rotational position is corrected, for example by driving parts of the belt, in the case of a strap conveyor only some straps thereof, at a different speed to the rest of the belt, whereby the article lying on it can be rotated by an angle of rotation about an upright axis.
Especially if the actual position has to be changed with respect to the transverse position as well as with respect to the rotational position, belt conveyors consisting of a plurality of narrow straps lying next to each other and drivable separately controlled for the change of the rotational position are preferably suitable for this purpose, if the downstream deflecting pulleys for these belts can be displaced—at least jointly, ideally individually controlled—in transverse direction so that they run inclined to the general passage direction through the machine and can thus also displace the article in transverse position, at least by a part of the transverse distance between the two deflecting pulleys.
Since an incorrect actual position is usually caused by the cutting process, it is desirable to determine the cause of the deviation from the target position, and preferably to determine it automatically, instead of spending a lot of time on manual determination or try-and-error position correction.
According to the invention, the cause is therefore deduced from the type and degree of deviation from the target position, for which the control of the machine must be embodied, which is possible in particular if the control contains artificial intelligence.
Depending on the determined cause, the control can then change the causal parameter.
For example, a cutting surface on the blade that has become radially too long due to regrinding can cause the cut-off slice to adhere too long to the blade and thus be ejected in a slightly wrong direction.
The same can be the case if the material of the slice adheres too strongly, for example because the temperature of the slice is too high or the flexibility of the slice is too low.
In this case, or in the case of other causes, the control can either automatically change the speed of the blade or ask the operator to change the blade and, in particular, to prescribe a different design for the new blade and/or to ask for one or more of the product parameters of the next calibers to be sliced to be changed.
In this way, it is also possible to memorize from each cutting situation the parameters that have led to a correct actual position, and to refer back to these parameters from the beginning for the same or similar new cutting job.
In order to be able to draw such conclusions, it is important that as many as possible of the machine parameters on the machine side as well as the caliber parameters on the product side are known or determined, and therefore the corresponding sensors must be available on the machine for the determination if such an automatic cause determination is to be carried out.
This can greatly reduce the dead times of the machine, in particular the setting time of the machine for a new product.
A correct actual position of the slice is particularly difficult to achieve if the slice is not deposited lying in one plane, but is deposited as a folded slice, which is known to be achieved by arranging a rotating folding shaft in the falling path of the separated slice, which can not only rotate during the falling of the slice, but also change its position in the process.
In this case, if the actual shape of the folded slice is found to deviate from the target shape, especially if the deviation is in the shape of the fold, the speed of the folding shaft and/or the position or path of the folding shaft are automatically changed during the folding process if a predetermined acceptance value is exceeded. This can also be a change in the path of the folding shaft over part of the time or the entire time of the folding process.
Preferably, in a multi-track slicing machine, this is done separately for each track if separately controllable folding shafts are available.
In this way, a time-consuming manual try and error search for the correct folding process is avoided.
With regard to the slicing machine with the known basic components of cutting unit, feed unit for calibers, discharge unit for conveying the slices or portions—which, as is known, comprises at least one further conveyor in addition to the portioning belt—and with the additional presence of a camera for detecting the actual position of the slice or portion on the discharge unit, the control system of the machine, which is always present, must be embodied and intended to carry out the aforesaid method in order to achieve the advantages set out for the process.
Preferably, the camera for detecting the actual position is directed to the first and/or the second belt of the discharge conveyor unit, to the second belt preferably if it is a weighing belt.
If the second belt is not a weighing belt, the camera can either be directed to the portioning belt and the second belt is already embodied as a displacement belt for changing the position of the article, or the camera is directed to this second belt and by means of this belt, which is embodied as a change belt, the change of position of the article is also carried out immediately.
The camera is preferably arranged above the respective belt, but in special situations it could also be arranged below the upper run, which must then preferably be transparent, and in particular be embodied as a camera with only a small extension in the passage direction, in particular as a line camera.
The embodiment as a line camera is preferably useful if the displacement belt is not the detection belt, but a downstream belt.
Preferably, the slicing machine has sensors that are data-connected to the control.
The sensors should be able to detect machine parameters, e.g.,
Sensors can also be present to determine caliber parameters, preferably upstream of the blade unit, for example
For transverse displacement, a displacement belt can be positioned in a belt cassette which is controlled as a whole and can be displaced transversely, preferably by means of a simple crank drive, in the transverse direction.
Another possibility is that the belt is a strap conveyor whose downstream deflecting rollers are transversely displaceable, preferably individually and independently of each other, whereby the transverse position of an article transported thereon can be changed.
If the running speed of the belts can also be controlled individually and independently of each other, the rotational position of the article lying on it can also be changed.
If the slicing machine comprises a folding unit with a folding shaft which can be displaced in a controlled manner as well as rotated, the camera should be embodied and arranged in such a way that it is also able to determine the folding shape of the folded slice and the control should be embodied in such a way that it can compare this folded actual shape with a folded target shape, which can be solved in particular by means of artificial intelligence in the control.
Based on the determined discrepancy, the control can then—if the discrepancy is above a predetermined acceptance value—automatically control the folding shaft differently during the folding process so that the actual shape then corresponds to the target shape.
Preferably, the folding unit should be embodied separately for each path in a multi-path slicing machine.
Embodiments according to the invention are described in more detail below by way of example. They show:
The basic structure of the slicer 1 is that to a cutting unit 7 with a rotating sickle blade 3 are fed, in this case, four product calibers K lying next to each other transversely to the feeding direction 10 by a feed unit 20, from the front ends of which the rotating sickle blade 3 cuts off a slice S in each case during one revolution, i.e., quasi simultaneously.
The feed unit 20 comprises a feed conveyor 4 in the form of an endless, circulating feed belt 4, the upper run of which can be driven at least in the feeding direction 10, and preferably also in the opposite direction. The calibers K rest on the feed belt 4 and are positioned in the transverse direction 11 by spacers 15 which project radially outwards from the feed belt 4.
For cutting the product calibers K, the feed conveyor 4 is in the inclined position shown in
The rear end of a caliber K lying in the feed unit 20 is in each case held form-fit by a gripper 14a-d with the aid of gripper claws 16. These grippers 14a-14d are attached to a common gripper unit 13, which can be moved along a rod-shaped gripper guide 18 in the feed direction 10.
Both the feed of the gripper unit 13 and the feed conveyor 4 can be driven in a controlled manner, but the actual feed speed of the calibers K is effected by a so-called upper and lower driven product guide 8, 9, which engage on the upper and lower sides of the calibers K to be cut open in their front end regions near the blade unit 7:
The front ends of the calibers K are each guided through a product openings 6a-d provided for each caliber, which are formed in a plate-shaped cutting frame 5. Immediately in front of the front end face of the cutting frame 5, which points obliquely downwards, runs the cutting plane 3″, in which the sickle blade 3 rotates with its cutting edge 3a and thus cuts off the projection of the calibers K from the cutting frame 5 as a slice S. The cutting plane 3″ is defined by the cutting edge 3a. The cutting plane 3″ is spanned by the two transverse directions 11, 12.
Here, the inner circumference of the goggle openings 6a-d of the cutting edge 3a of the blade 3 serves as a counter cutting edge.
Frequently, the two product guides 8, 9 in the 1st transverse direction 11 are separate for each caliber K and can be controlled separately.
The upper product guide 8 can be displaceable in the 2nd transverse direction 12—which is perpendicular to the surface of the upper run of the feed conveyor 4 tilted up into the cutting position—for adaptation to the height H of the caliber K in this direction. Furthermore, at least one of the product guides 8, 9 can be embodied so as to be pivotable about one of its deflecting pulleys 8a, 8b, 9a, 9b, in order to be able to change to a limited extent the direction of the conveyor belt resting against the caliber K.
The slice S, which is at an angle in space and has just been cut off, falls onto a discharge unit 17 starting below the cutting frame 5, which in this case consists of several discharge conveyors 17a, b, c arranged one behind the other with their upper runs approximately aligned in the passage direction 10*.
Below the feed unit 20 there is an approximately horizontally running end piece conveyor 21, also in the form of an endlessly circulating conveyor belt, which starts with its front end below the cutting frame 5 and directly below or behind the discharge unit 17 and with its upper run transports end pieces falling on it to the rear against the passage direction 10*.
Therefore, at least the first conveyor 17a in passage direction 10* can be driven with its upper run against the passage direction 10*, so that an end piece falling thereon, for example, can be transported to the rear and falls onto the lower-lying end piece conveyor 21.
In the transport direction 10 in which the articles A—here a portion P consisting of only two shingled slices S—are to be conveyed away, there are three discharge conveyors 17a, b, c in succession, in each case endlessly circulating belts, which circulate via an upstream deflecting roller 17a1, 17b1, 17c1 and a downstream deflecting roller 17a2, 17b2, 17c2 in the transport direction 10 and on the upper runs of which the article A rests for transport and transfer to the next conveyor. In reality, the second and third conveyors 17b, 17c are considerably longer in the transport direction 10 than the first conveyor 17a.
As shown in the area on the right, the overhang of the caliber K projecting downward from the inclined cutting frame 5 is cut off by means of the blade 3, which is moved closely along the underside of the cutting frame 5, and the slices S fall one after the other onto the portioning belt 17a, which is moved one step by step after each slice S has impacted to produce a shingled portion P in the longitudinal direction, the transport direction 10.
Once the article A to be produced, in this case the portion P, has been produced on the portioning belt 17a, the latter is set in motion and the article A is transferred to the subsequent discharge belt 17b, which in this case is embodied as a weighing belt WB and encloses a scale, not shown, in order to weigh the article A thereon, for which purpose the discharge belt 17b is generally stopped briefly.
Thereafter, by driving the discharge belt 17b, the article A is transferred to the next belt, the transfer belt 17c, whose main task is to transfer the article A to a subsequent conveyor of another processing unit.
As can be seen, the first two conveyors 17a, 17b are usually mounted and supported in a pivot unit 30, usually in its pivot frame 30a, which is usually pivotable about a pivot axis 30′ arranged near its downstream end—which here coincides with the rotation axis of the downstream deflecting roller 17b2 of the discharge conveyor 17b—in order, in particular, to determine the angle and the distance in height of the portioning belt 17a relative to the cutting frame 5 and thus the drop distance for the slices S as required.
For the same reason, the portioning belt 17a is usually additionally pivotable about a pivot axis running in transverse direction 11, which is usually identical with the rotation axis of the downstream deflecting roller 17a2 of the portioning belt 17a, relative to the pivot frame 30a.
The drive of the portioning belt 17a, i.e., of its conveyor belt, is realized via a drive motor A17a, which is arranged here coaxially on the rotation axis of the downstream deflecting roller 17a2, and likewise coaxially thereto can be arranged the pivot motor S17a, which effects the pivoting of the portioning belt 17a relative to the pivot frame 30a.
The pivoting of the entire pivoting unit 30 is effected by means of a pivot motor S30, which is arranged coaxially to the pivot axis and thus to the downstream deflecting roller 17b2, while the drive motor A17b for the conveyor belt of the discharge conveyor 17b is arranged coaxially to the other deflecting roller 17b1 of the discharge conveyor 17b.
The special feature according to the invention consists first of all in the fact that a camera 22 is arranged above the discharge conveyor 17—two of which are shown in
While a camera 22 which is to record this actual position on the discharge conveyor 17b, i.e., the middle of the three belts, can be arranged centrally above it, this is not possible in the case of detection on the portioning belt 17a because of the inclined overhanging cutting frame 5 and the blade 3—the flying circle 3* of which is drawn in
Such a camera, which is shown here on the right, has a correspondingly inclined viewing angle of the portioning belt 17a, so when the latter is tilted down with its upstream end in order to reduce the angle between the cutting frame 5 and the upper run of the portioning belt 17a. This belt view complicates the evaluation and the accuracy of the evaluation of the actual position of the article A, which is why the middle belt, i.e., the discharge belt 17b, is preferably also used as detection belt DB for determining the actual position of the article thereon, especially if it is embodied as weighing belt WB.
In the event of a deviation of the actual position from the target position in transverse direction 11, in any case greater than a predetermined tolerance value, this actual position is corrected, as shown in
Its deflecting rollers 17c1, 17c2 are mounted as a first solution in a so-called belt cassette 23, usually an enclosing frame as seen in plan view, and also the drive motor A17c for this conveyor belt is attached to this frame of the belt cassette 23.
The entire belt cassette 23 can be displaced in a controlled manner for a desired amount in the transverse direction 11, for example along guides 23a, b as shown in
If, therefore, as seen in the top view of
The same aim is achieved with the second solution, also shown in a top view in
If the downstream deflecting roller 17c2 can be moved in a controlled manner in the transverse direction 11—for which a crank drive 28+29, as described in
If the target position of the article A on the detection belt DB, here the middle discharge conveyor 17b, was different from the target position by the transverse distance Q, then for the correction of the position of the article the downstream deflecting roller 17c2 is deflected in the corresponding direction by this transverse distance Q and remains in this position during the time in which the article A is on this transfer conveyor 17c.
As can be seen in
Furthermore, the belt conveyor 17c shown in
For this purpose, during transport along the strap conveyor 17c, the individual straps 24 are driven at different speeds—individually or in groups—in order to thereby rotate the article A lying thereon.
If, for example, the upper straps 24 shown in
In this case, however, a single drive motor A17c—as shown—is not sufficient, e.g., for the entire driving of deflecting roller e.g., 17c1, but the individual straps or groups of straps must be separately drivable for this purpose and have a separate drive motor for this purpose.
In addition, various sensors are shown in
Thus, the temperature of the front surface of the caliber K to be cut can be measured by means of a sensor 25, which can be located, for example, on the base frame of the machine. Before the caliber K is cut, this is the surface temperature, and after the first centimeters have been cut off—if this is done quickly enough—it is the core temperature of the caliber K. The temperature influences the adhesion of the slices S to the blade 3 and also the bending stiffness of the slices and thus also the shape of the slice S when it hits the portioning belt 17a and in particular the result of the slice folding process, if such a process is carried out.
For this purpose, a sensor 26, whose measuring direction is an approximately horizontal transverse direction, can detect the shape of the fold of a folded slice lying on the, in this case, middle conveyor 17b and compare it with a target shape of a folded slice.
With the same viewing direction, a sensor 27 with its detection direction in transverse direction 11 can be arranged just below the cutting frame 5 in the falling path of the slices S, which detects the bending of the falling slices in the side view, from which the bending stiffness of the slice S can also be concluded.
In order to determine the salt content of the caliber and/or the electrical conductivity of the caliber and from this the water content, a sensor 28 contacting the caliber K is usually necessary, which can be arranged in the feed unit 20 for the calibers K, for example in the gap between the driven lower product guide 9 and the feed conveyor 4, which however are not shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 102020130342.4 | Nov 2020 | DE | national |
