Patent Application
20240158120
This application claims foreign priority benefits under 35 U.S.C. § 119(a)-(d) to German patent application number DE 102022130350.0, filed Nov. 16, 2022, which is incorporated by reference in its entirety.
The disclosure relates to a packaging line comprising:
Both the discharge unit and the infeed unit consist of a plurality of conveyor belts arranged one behind the other in the direction of travel through the machine and, in the case of multi-track machines, also of a plurality of conveyor belts arranged side by side transversely to one another.
In practice, such an infeed unit is called an inserter or an infeed line. The infeed unit and the discharge unit of the slicing machine together form a transport route over which the portions must be transported from their creation to their insertion into or onto the packaging element.
The slicer is often referred to below, but this is not intended to limit the disclosure to this design of slicing machine.
In the case of such a packaging line, too, the focus is on its performance, usually specified in terms of the cycle time with which the packaging elements, which generally move forward step by step, are moved in the packaging machine.
This is because the packaging machine is usually a thermoforming packaging machine in which, immediately upstream of the infeed station at which the portions are stored on or in the packaging elements, a strip of thermoformable plastic foil is thermoformed in portions at a standstill, as a result of which packaging troughs are designed in the foil band, usually several packaging troughs in succession per track per thermoforming operation in the direction of travel.
The number and arrangement of packaging trays produced in a single thermoforming operation, or the corresponding number and arrangement of portions to be placed in these trays, is referred to as the format. Since these are usually multi-track slicing machines and also multi-track packaging machines, the troughs and corresponding portions form into a two-dimensional format.
Since, due to the step-by-step thermoforming process (thermoforming cycle), the foil band also moves forward step-by-step at the infeed station, a complete format of portions must be inserted into the corresponding format of trays at the infeed station each time it moves forward (infeed cycle=thermoforming cycle).
On the one hand, the infeed unit provides the representation of the portions in the correct formats and at the correct locations of the infeed unit, and on the other hand, it represents a buffer for portions and whole formats, in order that in the event of an interruption of the slicing operation—which regularly occurs when loading the slicer with one or more new product calibres—the packaging machine can continue to operate fed from this buffer.
For this reason, the slicing power or cutting capacity of the slicer is usually slightly higher than the infeed power or capacity of the packaging machine, in the case of a thermoforming packaging machine, usually its thermoforming power or capacity or other power limiting the packaging machine power.
Nevertheless, the average cycle frequency and thus the infeed power (with an inverse analogous increase in cycle time) of the packaging machine decreases when the cutting operation is interrupted, but not during the interruption, since during this time the packaging machine is fed from the buffer, but after the cutting operation has been resumed, since time is needed to close the gap between the last format in the inserter and the new portions produced on the transport route after the interruption.
This decrease in cycle frequency could be shortened by choosing the cutting power of the slicer much higher than the power of the packaging machine, which, however, represents a high additional effort on the part of the slicer.
Not all buffer belts within the infeed unit and, for the same reason, within the discharge unit can be considered as buffer bands, because a buffer belt must be able to transfer the one or more portions stored on it to the following band with positional accuracy even after a standstill.
Since the packaging elements, in particular the trough band, have a defined running speed during their movement phases, the last band of the infeed insertion unit, the so-called insertion band, which ejects the format on it, e.g. into the troughs, must also have the same running speed during insertion and thus frequently also the upstream bands, particularly buffer bands.
A conveyor band can therefore be ruled out as a buffer band because it is too short to bring a portion stored on it to this running speed when it is put into operation until the end of this conveyor band. If there is room for more than one portion on this buffer band in succession, only one or a part of these portion positions can be enabled as buffer positions, as the above condition is fulfilled for this, but one or some other buffer positions on this buffer band are not enabled for this, hereinafter referred to as non-buffer positions.
Similarly, a conveyor band cannot be used as a buffer band if it is not driven by a servo motor, since it cannot then be controlled precisely in terms of time and speed profile, which is why synchronous and positionally accurate transfer to a subsequent band is not possible.
Therefore—see
Functions such as weighing the portions, discharging reject portions, adjusting the portions running side by side to the track spacing of the packaging machine, rotating and aligning the portions, etc. are usually provided by the conveyor belts of the discharge unit of the slicer or the downstream first belts of the inserter infeed unit, in that these contain appropriately designed conveyor belts.
It is therefore an object in accordance with the disclosure to provide a method for operating a packaging line which minimizes and in particular avoids the increase in the average cycle time of the packaging machine due to an interruption in the slicing operation of the slicing machine, and to provide a packaging line suitable for this purpose without significantly increasing the constructional expenditure for the packaging line.
With respect to the method of operating a packaging line, typically comprising as set forth:
wherein
in normal operation, the slicing machine is operated only with such a real slicing capacity that—per track—the number of portions available on the transport route corresponds at most to the total number of depositing positions for one portion each, the buffer positions, available in the buffer route.
This ensures that in the event of an interruption of the infeed process at the infeed point and consequent immediate stop of the cutting operation, the portions present on the transport route upstream of the powder route can be transported further into the buffer route and can all be accommodated there.
Since the buffer belts there each have servo motors as drives, after a restart of the inserter operation, the contents of the buffer route can gradually be correctly inserted at the insertion point onto or into the packaging element.
The real cutting power or capacity is the separated number of slices per unit time and particularly per track. The maximum cutting power, which is limited by the maximum speed of the knife of the slicing, is usually somewhat higher.
However, in order to set the slicing machine to a given real cutting power, the speed of the knife is not reduced, but the speed is used, which would result in the maximum number of slices per time unit, if slices were also cut off with each rotation of the knife. However, such a number of empty cuts is provided—in which the knife does not cut off any slice due to lack of contact with the calibre—that instead of the possible maximum cutting power, the desired lower real cutting power is present.
A storage position for a portion is understood to be the room, in particular the extension in the direction of transport, at which a portion can be stored on a conveyor band. Thus, if there is room for two portions one behind the other in the direction of transport on one lane of a conveyor band, but there is no room for a third portion, this conveyor belt has two storage positions.
For example, if the buffer route comprises four buffer belts, each of which is long enough to have two storage positions for one portion each, the buffer route has a total of eight storage positions.
The existing object is achieved by the fact that in the special case of a foreseeable interruption of the cutting operation of the slicing machine, the slicing machine is temporarily operated with a real cutting power which is so much higher than the real cutting power that the number of portions per track in the buffer route reaches a special number which is higher by a predetermined special difference than the number of buffer positions on the buffer route.
The number of normal buffer positions on the buffer route together with the additional special difference released in special operation thus results in the increased special number of portions that may be present on the entire transport route at maximum, i.e.:
number of buffer positions+special difference=increased special number.
This solution is based on the assumption that during the short period of special operation, in which the transport route is more heavily occupied with portions than in normal operation, i.e. substantially the period of interruption of the cutting operation of the slicer, presumably no standstill of the infeed insertion unit and/or the discharge unit of the slicer will be additionally forced by other circumstances, but these will continue to run and the infeed insertion unit will continue to supply the packaging machine with formats by stepwise forward movement.
This continuously frees up buffer positions on the infeed inserter unit, because otherwise the portions—particularly those on non-buffer belts—would have to be discharged or at least manually inserted, as they could no longer be automatically transferred to the downstream belts with positional accuracy.
Preferably, the special difference is determined in such a manner that the special number per lane corresponds to a maximum of the total number of storage positions for portions available in the transport route. This ensures that a separate deposit position is also available for each portion present on the transport route.
To keep the described risk as low as possible, the period of increased occupancy is kept as short as possible. For this purpose, the preliminary period is preferably placed immediately before the stop of the cutting operation.
For the same reason, the length of the preliminary period is chosen in such a manner that the special number is reached only with the last cutting operation before the stop of the slicing operation.
Likewise, the preliminary period is started particularly as late as possible, in particular so late that just the desired special number can be built up until the interruption.
As a rule, the packaging means are moved forward step by step in the packaging machine with receptacle of a format consisting of a plurality of portions—one behind the other in the transport direction and, in the case of a multi-track machine, a plurality of portions next to one another in the transverse direction. In this process, the formats are assembled from individual portions with the help of the infeed unit.
Then the special number per track corresponds at most to the portion number per track of two formats, at most to the portion number per track of only one format, in order not to drive up the additional occupancy too much.
If, however, the discharge unit and/or the infeed unit come to a standstill during the period of special operation, i.e. during the increased occupancy of the transport route, the portions on the non-buffer belts are normally discharged from the packaging line and/or placed manually on the packaging means when the line is restarted.
A packaging line for the production and packaging of portions each comprising one or more slices separated from a calibre of product generally comprises, as is well known:
With regard to such a packaging line, the existing object is achieved according to the disclosure in that the packaging line, in particular its controller, is designed in such a way that it is capable of performing the method described above.
This makes it possible to achieve the advantages described on the basis of the method.
Preferably, the packaging line comprises for this purpose:
and/or
and/or
and/or
and/or
and/or
and/or
and/or
With the help of these conveyors in the packaging line, the intended purpose can be achieved very easily.
Embodiments in accordance with the disclosure are described in more detail below by way of example. In the figures:
It can be seen that the basic structure of a slicer 100 according to the prior art is that a cutting unit 7 with a knife 3 rotating about a knife axis 3′, in this case a sickle knife 3, is fed with several, in this case four, product calibres K lying transversely to the feed direction 10 next to one another on a feed conveyor 4 with spacers 15 of the feed conveyor 4 between them by this feed unit 20, from the front ends of which the rotating knife 3 cuts off a slice S with its cutting edge 3a in each case in one operation, that is to say almost simultaneously.
For the cutting of the product calibres K, the feed conveyor 4 is in the cutting position shown in
The rear end of each calibre K lying in the feed unit 20 is—see
In this case, both the feed of the gripper slide 13 and of the feed conveyor 4 can be driven in a controlled manner, wherein, however, the actual feed speed of the calibres K is effected by a so-called upper and lower product guide 8, 9 which is also driven in a controlled manner and which engages the upper side and lower side of the calibres K to be cut open in their front end areas near the cutting unit 7.
The front ends of the calibres K are guided in each case through a so-called product opening 6a-d of a plate-shaped cutting frame 5, wherein directly in front of the front end face of the cutting frame 5, which faces obliquely downwards, extends the cutting plane 3″ in which the knife 3 rotates with its cutting edge 3a and thus cuts off the projection of the calibres K from the cutting frame 5 as a slice S, as can be seen better in the principle representation of
In this case, the inner circumference of the product openings 6a-d serves as a counter cutting edge of the cutting edge 3a of the knife 3.
Since both product guides 8, 9 can be driven in a controlled manner, particularly independently of one another and/or possibly separately for each track SP1 to SP4, these determine the—continuous or clocked—feed speed of the calibres K through the cutting frame 5.
Below the feed conveyor unit 20—see
The slices S, which are at an angle in the room when they are cut off, fall onto a discharge unit 17 which starts below the cutting frame 5 and extends in the direction of travel 10*, and which in this case consists of several discharge units 17a, b, c arranged one behind the other with their upper runs approximately aligned in the direction of travel 10*, of which the first discharge unit 17a in the direction of travel 10 can be designed as a portioning band 17a.
The slices S can hit the discharge unit 17 individually and spaced apart from one another in the direction of travel 10* or, by appropriate control of the portioning belt 17a of the discharge unit 17—whose movement, like almost all moving parts, is controlled by the controller 1*— form shingled (see
The side view of
The packaging line 1 shown in
Downstream of this is the actual buffer route 30, consisting of one or more, in the present case three, buffer bands 27.1-27.3, wherein in the present case the equalizing or balancing band 25 and the format band 26 also still belong to the buffer route 30, since they also—apart from the above-mentioned functions—also fulfil a buffer function as buffer bands.
The buffer bands 27.3 and 27.2 can each accommodate at least one format F of portions P, whereas the buffer band 27.1 can only accommodate a part of a format F, in this case only one portion, while the immediately preceding so-called format band 26 can also accommodate a portion P, so that both can buffer a format F together, in particular in the correct relative position of the two portions P of which it consists with respect to each other, especially in the direction of travel 10*.
At the end, the infeed band 28, which is directed downwards at an angle, stores the format F, consisting in this case of eight portions P, on the thermoforming band TB passing underneath it in the analogue format F* from troughs M of the thermoforming band TB, for which the thermoforming band TB and the infeed band 28 are brought to the same speed in the direction of travel 10*.
It goes without saying that the successive bands are so closely arranged to one another that they are able to take a corresponding portion P from the upstream previous band and pass it on to the downstream next band.
The length of the format F, F* in the direction of travel 10* and/or the cycle frequency as well as the speed in their movement phases are determined by how many troughs M are deep-drawn one after the other in the direction of travel 10*— and of course next to one another in the transverse direction 11, this usually simultaneously over all tracks—in the deep-drawing station between the upper die 303 and the lower die 304 from the flat deep-drawing band TB.
In the direction of travel 10*, a format F* comprises two troughs M one behind the other per track SP1-SP4 and, similarly, a format F comprises two portions P per track SP1-SP4.
Here,
In normal operation, there are 9 portions in the present case because the buffer route 30, i.e. from the compensation or balancing band 25 to the infeed band 28, offers 9 storage positions for one portion P each, including per track SP1-SP4.
The portions distributed over the entire transport route 217 in the state shown could therefore be transported further until they are all within the buffer route 30, from where a position-accurate transfer and insertion into the troughs M as packages or packaging means V would be possible even after a standstill of bands of the transport route.
At the time shown, therefore, in
there are within the buffer route 30:
wherein the bands 25 and 26 together fulfil the function of a format band on which, in total, two portions P are arranged in succession per track SP1-SP4 at the correct distance from one another.
Upstream of buffer route 30, there is the following per track:
In contrast,
In this case, 8 portions per track were released as a special difference, so that compared to normal operation with 9 portions per track in accordance with
The additionally released 8 portions are the portions created last, wherein during their production the remaining portions P were transported on accordingly, so that above all the buffer route 30 is now loaded more heavily, in the present case completely, in that now, in comparison with the state of
In the special operation shown in
However, for the special operation, a special difference of further portion positions for the receptacle of portions P to be produced is now released and also filled, which together with the normal buffer results in the released special number. In the present case, the released special difference is the total number of free portion positions that the non-buffer bands have.
From this it is clear that—provided there is no standstill of the infeed unit 200 during the interruption of the cutting operation—during the interruption of the cutting operation the packaging machine 300 can be supplied with formats F not only from the buffer route 30, but from the entire infeed unit 200.
Meanwhile, the free portion positions created mainly in the upstream area of the infeed unit 200 are closed by the slicer 100—which then creates portions P faster than they are consumed by the packaging machine 300—faster after the cutting operation is resumed than during normal operation until the cutting operation is interrupted.
How this is done and for what purpose is illustrated by
On the one hand, as in the case of the infeed line 1 in accordance with
On the other hand, the slicer 100, which can produce one slice S per track at regular time distances corresponding to the circulation time of the knife, can produce more than the 6 slices per track required for one format, namely 8 slices, within an infeed cycle time ET. In normal operation, therefore, after production of the 6 slices required for a format F, two blank cuts are performed within an infeed cycle time ET, e.g. by retracting the calibre K slightly to the rear for this purpose and thus no longer making contact with the knife 3.
Thus, the occupancy of the transport route 217 with portions P changes cyclically, for example, between 21 and 27 portions.
If, in accordance with
Since, after loading, one wants to increase the average occupancy of the transport route 217 back to the same level and thus the same buffer size as before loading as a safety measure, no empty cuts are performed by the slicer 100 during the first infeed cycle times ET, so that it produces eight instead of six slices S per lane in one infeed cycle time ET.
As can be seen, a significant number of infeed cycle times ET are required to achieve occupancy of the transport route as it was prior to the interruption of operation of the slicer 100.
This is improved in accordance with the disclosure by introducing a special operation in accordance with
With the same duration of the loading process, the loading at the end of the cutting operation thus only drops to 11, and accordingly, with appropriate operation of the slicer after the end of the interruption of operation of the slicer, initially without empty cuts, the original loading level is reached all the more quickly.
This advantage outweighs the disadvantage that during overcrowding of the transport route shortly before the slicer 100 stops, an additional stop of the infeed unit 200 would result in some portions P either having to be manually inserted into the packaging machine 300 or becoming rejects.
As one skilled in the art would understand, the controller 1*, as well an any other unit, machine, apparatus, element, sensor, device, component, system, subsystem, arrangement, or the like described herein may individually, collectively, or in any combination comprise appropriate circuitry, such as one or more appropriately programmed processors (e.g., one or more microprocessors including central processing units (CPU)) and associated memory, which may include stored operating system software and/or application software executable by the processor(s) for controlling operation thereof and/or for performing the particular algorithms represented by the various functions and/or operations (e.g., methods) described herein, including interaction and/or cooperation between any such controller, unit, machine, apparatus, element, sensor, device, component, system, subsystem, arrangement, or the like. One or more of such processors, as well as other circuitry and/or hardware, may be included in a single ASIC (Application-Specific Integrated Circuitry), or several processors and various circuitry and/or hardware may be distributed among several separate components, whether individually packaged or assembled into a SoC (System-on-a-Chip).
| Number | Date | Country | Kind |
|---|---|---|---|
| 102022130350.0 | Nov 2022 | DE | national |
