This patent application claims priority of Italian Patent Application No. 102021000005468 filed on Mar. 9, 2021, the entire disclosure of which is incorporated herein by reference.
The present invention relates to a method to set up a movable operating member of an automatic machine for manufacturing or packaging consumer articles.
The present invention finds advantageous but not limiting application in an automatic packaging machine that manufactures packets of cigarettes and in the control method thereof, to which the following disclosure will make explicit reference without thereby losing generality.
An automatic packaging machine comprises a plurality of movable operating members which act on consumer articles (for example packets of cigarettes, food products, sanitary absorbent articles, etc.) to modify conformation, structure or position thereof. Generally, the movable operating members are mechanical parts of different shapes and sizes designed to process the consumer articles and are, in most cases, actuated by electric motors or pneumatic cylinders.
During the start-up of the automatic machine, due to the different assembly methods and the normal machining tolerances of the mechanical parts, it is often necessary, in order to obtain a high machining precision, to set up the movable operating members; namely, it is necessary to carry out calibration, filing, shimming and synchronization operations, which are necessary for the correct operation of the automatic machine. In the absence of this set up, in most cases, the product does not fall within the precision or quality specifications required by the customer, as the motion profile of the movable operating member does not accurately correspond to the one processed during the design stage of the automatic machine.
To date, these operations are carried out by expert technicians directly on site. These technicians insert shims and/or modify parts (by means of file, milling, cutting) in order to allow the movable operating member (namely, the last follower) to carry out the required processing with the desired precision.
The poor repeatability of these operations (each automatic machine is modified ad hoc according to the assembly and/or structural defects of the available parts) determines a non-calculable and difficult to record difference between automatic machines, or parts thereof, which should be identical.
Furthermore, the parts on which said technicians work, are usually mechanical parts (in particular portions of kinematic elements), since the main coordination procedure of the different motors belonging to an automatic machine has been, up to recent times, purely mechanical.
In addition, also due to the mechanical nature of the processed parts, these set up activities are rarely recorded and/or shared, thus causing a significant waste of time in understanding subsequent failures and in providing after-sales support to customers who purchase these automatic machines, as well as high difficulties in the mass production of identical machines.
Finally, the aforementioned technicians, although experts in assembly and set up, do not usually have the kinematic skills necessary to adjust the operating members according to their respective motion profiles, limiting their considerations according to the product and the desired movement thereof (namely, the effect of the aforementioned motion profiles). Therefore, in order to achieve set-up, these operators modify the motion profiles of the movable operating members in an empirical way, performing a large number of attempts before reaching the desired behaviour of the movable operating member. All this leads to an extension of the delivery times of the automatic machine.
The object of the present invention is to provide a method to set up a movable operating member of an automatic machine for manufacturing or packaging consumer articles, which is at least partially free from the drawbacks described above and, at the same time, is simple and inexpensive to obtain.
According to the present invention, a method is provided to set up a movable operating member of an automatic machine for manufacturing or packaging consumer articles according to what is claimed in the attached claims. A machine designed to implement the above method is also provided.
The claims describe preferred embodiments of the present invention forming an integral part of the present description.
The present invention will now be described with reference to the attached drawings, which illustrate some non-limiting embodiments thereof, wherein:
The automatic machine 1 comprises a base 2 on which a plurality of movable operating members are mounted (such as, for example, grippers, drums, pushers, counter-pushers, jumpers etc.), which carry out operations for manufacturing and/or packaging consumer articles (which in the non-limiting embodiment illustrated in
In particular, the automatic machine 1 comprises a wrapping unit 4 provided with a plurality of movable operating members, each of which is moved by a respective electric motor (or by any type of actuator device).
In the non-limiting embodiment of
In the non-limiting embodiment of
Therefore, the movable wheel 5, the pusher 7 and the counter-pusher 7′ are movable operating members, since they carry out processing (movements) on the packets 3. In some non-limiting examples, other movable operating members are sealing arms, for example to close the outer wrap (usually made of cellophane) of the packet 3 of cigarettes.
In the non-limiting embodiment illustrated in
In particular, the electric actuator systems 8, 9 and 9′ are connected to the movable operating members, namely, to the wheel 5, to the pusher 7 and to the counter-pusher 7′ with the interposition of a motion transmission system 12 (for example, as in the case of the pusher 7, a reducer 13 connected to a screw or an articulated quadrilateral which transforms the circular motion into linear motion, or, as in the case of the wheel 5, a reducer, for example epicyclic, which frees the wheel 5 from moving at exactly the same speed as the motor M).
In some non-limiting and not illustrated cases, the motion transmission system 12 is any device capable of transmitting the movement of the electrical actuator systems 8, 9 and 9′ to the respective movable operating members (in the embodiment of
According to some preferred but not limiting embodiments, the electric actuator systems 8, 9 and 9′ are asynchronous electric motors. In particular, the static power converters are actuators that control, on the basis of the desired method, the amount of current to be supplied to the respective electric actuator systems 8, 9 and 9′ and therefore control the electric motors M.
The automatic machine 1 comprises, furthermore, a control unit 14 (
Advantageously, the automatic machine 1 comprises an interface device 15 (illustrated in
In the non-limiting case of
In particular, the operator O will vary the motion profile of the motor M of the electric actuator system 9 by entering as a conversion parameter 50 an offset equal to the amount desired to increase the compression of the packet 3 or the stroke S of the pusher 7, all regardless of the motion transmission system 12.
Advantageously but not necessarily, the conversion parameter 50 is a parameter concerning the article to be produced (in this case the packets 3—and not to the motion of the motors M). In this way, the operator O is able, without the aid of technically expert personnel, to modify the behaviour of the automatic machine 1 by setting how the operator would like to modify the behaviour of the same on the article to be produced, rather than how the operator would like to modify the motion of the motors M. Therefore, the task of the operator O is simplified, since one can modify the motion profile of the motors M in a transparent way to the same, but referring exclusively to the conversion parameter 50, which defines an effect on the article to be processed. In other words, the conversion parameter 50 allows the operator O to set up the automatic machine by means of adjustments made at a higher conceptual level than the variation of the laws of motion of the individual motors M.
Advantageously but not necessarily, the conversion parameter 50 comprises a position of the article to be processed, its compression or a time or a force or a pressure of a given processing procedure.
In some non-limiting cases, the conversion parameter 50 comprises the format of article 3 being processed. In this way, the conversion parameter is used to scale parametric motion profiles (or families of motion profiles) according to the format (geometries, types of material, etc.) of the article being processed.
In some non-limiting cases, the conversion parameter 50 does not concern the format of the article 3 being processed, but exclusively the properties of (or deriving from) the processing carried out on the same.
Obviously, what has been described is also intended for cases other than the one mentioned wherein, in any case, the motion of a movable operating member is corrected by an operator O by means of the interface device 15, operating at the level of the movable operating member and not of the actuator system, correcting a respective conversion parameter 50. By way of example, other cases could be: an excessive stroke S that compresses the packet 3 inside the seat 6, an imprecise rotation of the wheel, a sealing time, etc.
According to the non-limiting embodiment of
Advantageously but not necessarily, the automatic machine 1 comprises a calculation unit 26, connected to the control unit 14 and configured to calculate the modified motion profiles on the basis of the modifications imparted by the operator O (to the conversion parameter 50) by means of the interface device 15. In particular, the profiles modified according to the variation of the conversion parameter 50 will then be commanded to the motors M of the automatic machine by means of the control unit 14.
In the flow diagram of
The method comprises a step 16 of defining a motion profile FP (illustrated in
In order to move the pusher with the desired motion profile, the method comprises the further step 17 of defining a motion profile SP of the electric actuator system 9, corresponding to the profile FP. In particular, the electric actuator system 9, through the motion transmission system 12, is mechanically connected to the movable operating member (namely, to the pusher 7) and moves the movable operating member with the motion profile FP. In other words, during the step 17, the motion profile SP is defined which the electric actuator system 9, namely, the electric motor M, must follow to make the pusher 7 move (namely, in this non-limiting case, the movable operating member, namely, the ultimate follower of the kinematic chain) with the profile FP.
According to the non-limiting example illustrated in
According to a non-limiting example such as the one illustrated in
Advantageously, the method also comprises a step 18 of determining possible imperfections in the processing of the articles (the packets 3) by the movable operating member (for example, the pusher 7). In other words, during this step, the correct operation of the movable operating member is checked. In the event that, during this step, no imperfections are found, the method concludes with step 30, in which the production of the packets 3 smoothly proceeds.
Advantageously, in the event that imperfections in the processing of the articles have been determined during the step 18, the method comprises the further step 19 of correcting the conversion parameter 50 (
According to the non-limiting embodiment of
Advantageously but not necessarily, the method comprises the further step 21 of modifying the control in order to control the electric actuator system 9 so as to carry out the corresponding modified profile MSP. In this way, the electric actuator system 9 moves, through the interposition of the motion transmission system 12, the pusher 7 with the desired and correct modified profile MFP.
Advantageously but not necessarily, the step 18 of determining possible imperfections and/or the step of correcting these imperfections are carried out by the operator O of the automatic machine 1, who uses the interface device 15 of the automatic machine 1. In this way, the setting up of a movable operating member is much faster with respect to the cases of the known art in which the operator must mechanically work certain components of the automatic machine 1, must forward the problem to an engineer, in particular a programming office, or must independently attempt to set the motion profiles by performing numerous experimental tests (which causes a waste of time and material).
In some preferred non-limiting cases, the method provides, furthermore, the step of defining a tolerance window to limit the modification of the conversion parameter 50. In particular, the limits of this tolerance window are illustrated to the operator O, by means of the interface device 15, during the correction step of the conversion parameter 50. In detail, therefore, the conversion parameter 50 allows one to convert the modification of the motion profiles described so far into the modification of a parameter correlated to the article to be produced.
Advantageously but not necessarily, the step 18 of determining possible imperfections is repeated following the step 19 of correcting the motion profile FP (more precisely following the step 21 of modifying the control of the electric actuator system 9). In particular, once the step 19 of correcting the profile FP has been carried out, a step 27 of analysing is carried out following which, if the motion profile MFP carried out by the movable operating member (for example by the pusher 7) is satisfactory (such as in
Advantageously but not necessarily, the motion profile FP and the corresponding motion profile SP comprise at least one work phase WP (the movable operating member moves) and at least one recovery phase RP (the movable operating member is still), during which the step 21 of modifying the control takes place. In this way, the correction of the control that modifies the profile FP in the profile MFP avoids disturbing the movement of the electric actuator system 9 (namely, of the motor M).
Advantageously but not necessarily, the method comprises a step 22 of identifying one or more centres K (knots) of the motion profile FP. At least part of these centres can be modified by varying the conversion parameter 50 by means of the interface device 15, more precisely by the operator O.
In particular, during the step of correlating the profile FP with at least one conversion parameter 50, a mathematical law is defined which links the conversion parameter 50 to the centres K. More in particular, therefore, the step 19 of correcting the profile FP is carried out by modifying the value of the conversion parameter 50, which determines a variation, according to the aforementioned correlation, of the position of the movable operating member at the centres K.
According to some non-limiting embodiments, such as the one illustrated in
Alternatively, or in addition, the motion profile FP comprises at least one polynomial function segment PF (for example a polynomial of order greater than or equal to the fifth, a B-Spline of order greater than or equal to the third, . . . ). In particular, the centres K are the inflection points or the junction points of these function segments LF and PF.
Advantageously but not necessarily, the method comprises a step 23 of defining a tolerance interval I to limit the modification of each centre K. According to some non-limiting embodiments, such as the one illustrated in
According to some further and non-limiting embodiments not illustrated, the tolerance interval I has a circular shape, the centre of which is a centre K.
Advantageously but not necessarily, before the step 20 during which the reverse kinematics is calculated, the control unit 14 checks (in the step 24 of
Advantageously but not necessarily, the method comprises a step 25 of gathering a plurality of data items (for example, which variables have been modified and how big the modification is) concerning step 19 of correcting the motion profile FP. In particular, plural data items are used to carry out corrections on the motion profile FP during the design phase of the machine 1 and/or to understand possible calculation errors. In this way, it is possible to identify any errors due to the purchase of mechanical parts, design or calculation errors of the motion profiles FPS. In this way it is also possible to keep track of the modifications made to each automatic machine both during the set-up step and with the passing of time and with increasing wear of the components.
In some advantageous and non-limiting cases, the plurality of gathered data items are used to train artificial intelligence systems. In particular, the plurality of gathered data items is analysed by means of decision tree algorithms to identify, in the case of similar corrections on a plurality of automatic machines 1 with similar parts, possible improvements to be implemented directly during the design phase.
According to some non-limiting embodiments, the step 21 of modifying the control takes place while the automatic machine 1 is still. In this way, it is possible to ensure greater safety for the operator O, who, following each modification, checks the effectiveness of the same.
According to other non-limiting embodiments, the step 21 of modifying the control takes place while the automatic machine 1 is moving. In this way, it is possible to speed up the set-up of the movable operating member (for example the pusher 7).
Advantageously but not necessarily, the motion profile FP and the motion SP profile have a cam relation with a master profile MP. The terminology “have a cam relation” we mean that the motion profiles FP and SP are connected to a reference profile (the master profile MP) with a variable ratio from moment to moment. In other words, with this terminology we mean, for example, that for each position of the master profile MP a position of the movable operating member (the pusher 7), is respectively defined (and therefore, unrelated to the electric actuator system 9). Therefore, the master profile MP is related, by points, to the motion profile FP of the movable operating member. This relationship is useful for maintaining the synchronism of all the movable operating members of the automatic machine, which, being connected directly or indirectly to the same master axis, follow the latter in a coordinated way not only at steady state, but also in the acceleration and deceleration steps of the automatic machine 1, in particular at the start and at the end of the production of the articles.
In some non-limiting cases, the master profile MP is the profile of a physical axis, such as a sprocket or wheel. In some non-limiting cases, the master profile MP is the profile of a virtual axis.
In
Advantageously and as illustrated in the non-limiting embodiment of
Advantageously but not necessarily, the correction of a conversion parameter 50 determines, in the case of multiple operating members 5, 7, 7′ to carry out a single function, the variation of a plurality of motion profiles FPS.
In the non-limiting embodiment of
According to some non-limiting embodiments, the master profile MP is a linear profile. In particular, at steady state, the master profile MP is a motion profile whose speed is constant.
According to some non-limiting embodiments, as the one illustrated in
According to some non-limiting and not illustrated embodiments, the motion profile FP and the motion profile SP are speed profiles.
Alternatively, or in addition, the motion profile FP and the SP motion profile determine torque profiles.
In some non-limiting cases, such as for example the embodiment of
Advantageously but not necessarily, the motion profile FP is divided into several subsections, which are divided by centres K. In particular, in the event that the format of the article to be processed is the conversion parameter 50, at least one of these subsections is scaled according to the format set and the others are interpolated accordingly.
In use, the operator O, once having determined imperfections in the processing of the articles (for example, once having determined a stroke S that is too short, a compression that is too light or an excessive/insufficient sealing), interacts with the control unit 14, by means of the interface device 15 correcting the respective conversion parameter 50, so as to modify the position of the centres K and therefore the shape of the motion profile FP. In the non-limiting embodiment of
Advantageously but not necessarily, the interface device 15 allows, in an additional and/or alternative way, the modification of the conversion parameter 50, modification also of part of the centres K (for example those comprised in the blocks 34 and whose ordinate can be modified in any case ensuring the correct functioning of the automatic machine 1), while it does not allow the modification of the values contained in the blocks 35, which represent constraints necessary for the correct processing of the articles.
Advantageously but not necessarily, the automatic machine 1 is configured to carry out the method described up to now.
Although the invention described above makes particular reference to a very precise embodiment, it is not to be considered limited to this embodiment, as it comprises all those alternatives, modifications or simplifications that would be evident to those skilled in the art, such as for example: the addition of additional actuators, another type of automatic machine other than a packaging machine for the tobacco industry, a different shape of the motion profiles, a different order of the phases of the method, a different number of motors, a different type of conversion parameters, etc.
The present invention has multiple advantages.
First of all, it allows one to set up a movable operating member directly on site and in a short time, without the waste of materials, such as shims, and the use of tools, such as drills, cutters, files, etc.
Furthermore, the method described above makes it possible to detect and calculate the difference between different automatic machines which are substantially similar, but which undergo different adjustments due to assembly and/or structural defects of the available parts.
Lastly, the present invention makes it possible to record and share a plurality of data items concerning the set up of the movable operating members and therefore, it allows to understand, at a distance and/or with the aid of digital systems, whether there have been errors in the machine design and possibly solve said errors.
Further advantages linked to the process according to the present invention relate to the improvement of the after-sales support. For example, a machine operator, if a movable operating member gradually wears out, can autonomously modify its motion profile based on what is seen or detected and therefore, the present invention avoids the immediate replacement of parts of the automatic machine and/or having to continually send experienced personnel to customers.
Number | Date | Country | Kind |
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102021000005468 | Mar 2021 | IT | national |
Filing Document | Filing Date | Country | Kind |
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PCT/IB2022/052089 | 3/9/2022 | WO |