PROCESS AND EQUIPMENT FOR WRAPPING PRODUCTS WITH STRETCHABLE FILM

Description

[0001] For packaging products, particularly food products, there is a known method of disposing the products in a tray made of expanded polystyrene, cardboard or other suitable material, and wrapping the whole with a stretchable and transparent film, normally made of any suitable thermoplastic material (PVC-PE). There are known machines for automatically forming packages of this type, being provided with means which unwind from a reel a portion of film whose length is matched to the dimensions of the product to be packaged, which dispose this film horizontally and subject it to a suitable stretching or pre-stretching and then raise the product to be packaged and force it against this portion of film and, while the product comes into contact with the film, there is also a known method of relaxing the tension of the film adequately with what is called a back-up phase. After the product has been raised, the flaps of the film are spread and overlapped in a suitable sequence under the tray carrying the product, and the tray is discharged, while at the correct time the wrapping film is cut and separated from the film obtained from the reel. A wrapping machine or packaging machine of this type is described, for example, in US Patent No. 3.967.433 (Bonfiglioli).

[0002] Known packaging machines using stretchable film, especially those of the latest generation, while operating at low speed, are designed to optimize the consumption of film and to adapt some of their movements automatically according to the characteristics, dimensions and shape of the product to be packaged.

[0003] The various operating elements of the packaging machines of known types are generally driven by actuators powered by electrical servo motors of various types, which operate at predetermined and substantially constant speeds. The diagrams showing the movement of the various operating elements of the machines have linear and disjointed variations. Moreover, the known packaging machines are not designed to modify the operating parameters of the said motors when there are variations in the ambient temperature and in the characteristics of the film used. A packaging machine which has been designed to operate without problems at an ambient temperature of approximately twenty degrees, for example, may produce packages which are partially torn or which deform the product and the tray excessively when it operates at a temperature of approximately four degrees Celsius, which is frequently required for maintenance of the cold sequence for the conservation of certain food products. A packaging machine which has been designed to operate with stretchable film of a particular make may develop operating problems when it is supplied with a film which, although stretchable, is of another make and has physical characteristics which are even slightly different from those of the film used in the initial testing.

[0004] Document EP 0 569 615 A discloses a machine for wrapping articles in a stretchable film comprising:

• means for unwinding from a reel a portion of stretchable film, whose length is proportional to the dimensions of the product to be wrapped, and means for pre-stretching the said film;
• means for raising the product against the pre-stretched film, while back-up means slacken the tension of the film;
• folding means which at the correct time fold and spread the flaps of the packaging film under the product which, by other means, is pushed to discharge it, while other means cut the said film and separate it from the supply reel;
• electric motors with electronic speed and phase control, for driving all the above mentioned means, said electric motors being controlled by a CPU;

[0005] EP 0 569 615 also discloses a process in accordance with the preamble of claim 1.

[0006] According to the present invention, there is proposed a new process as defined in claim 1 and equipment for wrapping products with stretchable film, in accordance with the teachings of EP 0 569 615 as above disclosed and outlined, characterized by the fact that the actuators moving the various operating means mentioned above are driven by electric motors, each of which is controlled by an electronic circuit card connected by an appropriate serial link to the master CPU or CPUs of the machine, in order to make the said actuators move with variable speed, with continuous variation and with accelerations and decelerations which make it possible to obtain the best compromise between the maximum speed of movement of the said means and the maximum use of the characteristics of stretchability of the film used, without the yielding or rupture of the said film.

[0007] Further characteristics of the invention, and the advantages derived therefrom, will be more clearly evident from the following description of a preferred embodiment of the invention, illustrated purely by way of example and without restriction in the figures on the six attached sheets of drawings, in which:

• Figs. 1 and 1a are diagrams of stretching at different speeds of two different types of stretchable film, the speed being applied in a known way;
• Figs. 2 and 2a show with the curves in broken lines the diagrams of stretching the films shown in Figures 1 and 1a, while the curves in solid lines represent the actual stretching profile obtained with a speed varied according to the invention;
• Figs. 3, 3a and 3b are speed/time diagrams of increasing stretching of films carried out by the new method;
• Fig. 4 shows a possible curve which represents the equation of acceleration and deceleration necessary to maintain the maximum possible degree of continuity of the movement in the phase of stretching the film according to the invention;
• Fig. 5 shows the speed curve corresponding to the preceding acceleration curve in Figure 4;
• Figs. 6 and 6a show the new speed curves of the phases of unwinding and stretching of the film in a packaging machine using stretchable film;
• Figs. 7 and 7a show the new speed curves for the phases of raising the product and back-up and partial closure of the wrapping film in a packaging machine using stretchable film;
• Figs. 8, 8a and 8b show the new speed curves for the phases of complete closure of the tray, cutting of the wrapping film and discharge of the product in a packaging machine using stretchable film;
• Fig. 9 is a block diagram of the electronic circuit which drives one of the variable speed motors of the packaging machine;
• Figs. 10, 11 and 12 are flow charts for the self-regulation of the operating program of the packaging machi with the variation of the film used and relate, respectively, to: the phases of unwinding and stretching; the phase of raising the product and back-up and partial closure of the package; and the phase of discharge, complete closure of the package and cutting of the film;
• Fig. 13 shows the main blocks of the self-regulation and calculation functions of the packaging machine during the normal operating cycle.

[0008] In known machines for wrapping products with stretchable film, for example in those cited in the introduction to the present disclosure or in wrapping or packaging machines of other types, the following three basic phases of manipulation of the film are present, wholly or in part: the phase of unwinding and stretching; the phase of wrapping the film around the top and sides of the tray; and the phase of total closure of the package, with the preparation of the film, if necessary, for wrapping the next product. The limitations of the known machines which carry out this type of wrapping are represented by the fact that these machines have not been designed to be able to make the best use of the physical and mechanical characteristics of the various films, since they are unable to adapt their movements to the characteristics of the stretchable films used or to the different behaviour of the films in the various situations in which they have to operate.

[0009] Each type of stretchable film used in machines of the type mentioned above or similar machines, whether it consists of PVC or PE, has its own physical characteristics which may be modified with a variation in the atmospheric conditions of the operating environment, particularly with a variation in humidity and especially with a variation in temperature, and these characteristics are also modified according to the speed at which the film is stretched and is deformed by the mechanical impact against the product raised in the packaging station.

[0010] Figures 1 and 1a are speed curves for the known stretching 13, 14, 15 and 16, 17, 18 of two films which, while they are both stretchable, have different characteristics. The film to which Figure 1 relates shows no yield before the rupture point 113, 114, 115, while the film to which Figure la relates has yield points 116, 117 before the rupture points 216, 217, 218. Figures 1 and 1a show how, in the same film, the slope of the curves and the rupture and yield points vary not only with a variation of temperature, but also, and especially, with a variation of the speed of stretching of the film. The slope of these curves increases with an increase in the stretch speed and with a decrease in ambient temperature. As the stretch speed increases and the ambient temperature decreases, the percentage elongation of the stretched film decreases, and the critical rupture or yield-rupture point of the film is reached more rapidly. It should also be noted that the stretchability of a particular film is related to the width of the portion of film subjected to stretching and that it increases with an increase in the width. The packaging machines in question are designed to operate with products of different sizes and therefore must operate with packaging films with different degrees of stretching.

[0011] For a correct use of the film, it is necessary to operate not only below the rupture point, but also below the yield point, to avoid entering an uncontrollable situation which may result in the tearing of the film in the subsequent impact phase, when the product is raised and pushed against the pre-stretched portion of film. To avoid entering this uncontrollable condition and to make maximum use of the stretchability of the film, it would be possible to operate at sufficiently low speeds, for example as indicated by the curves 15 and 18 in Figures 1 and 1a, but this would considerably restrict the output of the packaging machine and would be unacceptable. At present, the choice is made to operate at medium speed, for example as indicated by the curves 14 and 17, with the evident compromises resulting from this choice.

[0012] The invention is designed to provide the best compromise between speed of packaging and safety of operation, with the concept of a solution illustrated in Figures 2 and 2a, according to which a move is made from the initial higher speed curve to the lower speed curve, as described in the examples shown in Figures 1 and 1a , before the critical conditions of processing the film are reached, as indicated by the curves in solid lines 19 and 20. It is evident that the limited percentage elongations may rapidly be achieved with the new solution and that the greatest advantages are obtained when the packaging machine is required to operate on products of small and medium size, for which the width of the packaging film is limited and the stretching and stretchability of the said film are also limited.

[0013] The result of the behaviour observed previously, as seen not in the traction/percentage elongation diagram but in the speed/time diagram, is shown in Figures 3, 3a and 3b, from which it is easier to understand the complexity required to optimize the aforesaid compromise between speed and safety. The stretch curve 21 in Figure 3 shows a speed profile corresponding to a relatively small stretch, while the stretch curves 22 and 23 in Figures 3a and 3b correspond to larger stretches and relate to films having different physical characteristics. It is evident from the curves in Figures 3, 3a and 3b that, in the passage from one stretch speed to another, phases of acceleration and deceleration are necessary to ensure that the variation of the stretching of the film is, as far as possible, continuous, progressive and constant.

[0014] In Figure 4, the curve 24 shows the profile of the acceleration and deceleration required to maintain the maximum possible degree of continuity in the movement. The curve 25 in Figure 5, however, shows the profile of the speed corresponding to the preceding curve 24.

[0015] The same considerations apply to the phases of operation of the packaging machine following the pre-stretching phase. In the phase of impact of the product against the pre-stretched film, the shock following this impact, especially if it takes place at high speed, initiates complex processes which may result in instantaneous deformations, particularly in the parts acted on by the corners of the tray containing the product, which may cause the tearing and rupture of the film.

[0016] The considerations mentioned for the other phases are also applicable to the phases of discharge of the product from the packaging station, final closure of the package and cutting of the film.

[0017] In packaging machines of the type referred to, particularly in those of the latest generation, the various moving elements are already controlled by independent electric motors, with actuators of various kinds, and in certain cases the phases of operation of these machines are co-ordinated by an electronic intelligent system which supervises the general control of the machines. The development which the invention is designed to bring about in these machines consists in creating a system in which the parameters of the movement of the individual motors, regardless of their type, and the parameters of interpolation between the various movements, are functions of the following variables:

• the quality of the product to be wrapped;
• the dimensions and shape of the product to be wrapped;
• the elongation-yield and rupture curves of the film used, stored in a suitable way in the operating program of the machine;
• the behaviour of the film with the variation of the characteristics of the atmosphere of the operating environment, in particular the temperature parameters;
• the speeds relative to other simultaneous movements;
• the stresses due to interaction of the film and product.

[0018] Figures 6, 7 and 8 show the speed/time diagrams relating to the operation of the motors responsible for the implementation of the main critical phases of operation of a machine for packaging products with stretchable film.

[0019] The curves 26 of Figure 6 and the curves 27 of Figure 6a represent, on the speed/time scale, one of the possible combinations of the functions of movement calculated by the machine program by means of the operating variables and parameters. They relate to the phase of unwinding and pre-stretching of the film, where the movement of the elements and the corresponding interpolations are carried out to optimize the performance and the safety of operation, with the objective of having, at the end of the said phase, a film which is uniformly stretched and therefore uniformly stressed.

[0020] The curve 28 in Figure 7 and the curve 29 in Figure 7a, however, relate to a possible result of the optimization of the second phase of manipulation of the film, relative to the back-up during the raising of the product against the film and the subsequent partial wrapping of the product. In this phase, the critical point is represented by the shock of the product which may tear the wrapping film.

[0021] Finally, the curve 30 in Figure 8, the curve 31 in Figure 8a and the curve 32 in Figure 8b relate to the movements and corresponding interpolations of the final phases of manipulation of the film for the discharge of the product, the completion of the wrapping of the product, and the cutting of the film, with preparation of the wrapping for the next tray if necessary.

[0022] The critical movements of the said motors of the packaging machine are controlled by cards shown in heavy lines in the lower part of Figure 9. Each card which controls the motors relating to the critical movements of the machine comprises its own intelligent system which monitors all the functions of communication, calculation and control of the movement and which comprises, in particular, a movement microprocessor 33, a power supply 34 which generates the necessary voltages, an EPROM 35 which contains the basic logic and the fixed programs of the system, a RAM 36 to load both the operating parameters and the variable programs sent from the other microprocessors, a control logic 37, a power unit 38 to drive the motor 101 with an encoder, and a parking brake 39 if required, and an attached input/output (I/O) logic 40. The upper part of Figure 9 shows schematically the interface to a master CPU 41 consisting of a serial connection 42 and a synchronizing I/O 43. The numbers 44 and 45 indicate the EPROM and RAM of the master CPU and the number 46 indicates a control unit for other motors.

[0023] To make it possible to provide maximum flexibility in the individual movement and consequently maximum flexibility in the machine as a whole, the basic functions to be carried out by the control card of each motor may be listed as follows:

• control of the communication with the other CPU cards to transmit and receive the operating parameters and programs;
• processing of the parameters to calculate and execute the required profiles;
• control of the synchronizing signals between the various CPUs in both input and output;
• checking and maintenance of the synchronization of the movement of the controlled motor with that of the other motors, by means of the signals from the other controllers;
• control of the execution of the movement in a correct way or in any case within the tolerances specified by the procedure followed at that moment, by means of an encoder and power factor correction sensors which also enable the movement to be synchronized in the initialization phase;
• production of new movements with alternative profiles if the system is unable to provide the required profile within the specified tolerances;
• transfer to the master card of the new parameters calculated in case of modification of the profile;
• supply of new synchronization signals;
• automatic adjustment;
• test functions.

[0024] As mentioned previously in the introduction to this disclosure, another object of the invention is to make it possible for the packaging machine to operate with film having characteristics different from those of the stretchable film with which it was tested, without the need to enter critical situations which would cause tearing or rupture of the film and, especially, without the need to write the new operating programs into the machine software.

[0025] As stated previously, the principal phases during which the film may be in risk situations and which must be automatically adapted to the conditions of the said film are:

a) the phases of unwinding and stretching of the film;

b) the phases of back-up and partial closure of the wrapping;

c) the phases of complete closure of the wrapping film around the product, cutting of the film and discharge of the packaged product.

[0026] For these phases, operator-guided tests are provided, with automatic acquisition and processing of the operating parameters by the packaging machine. The self-learning test for the first group of phases will now be described with reference to the flow chart in Figure 10.

[0027] Block 47 represents " start control program". The acquisition and automatic storage program is started from the PC or from a dedicated user interface system.

[0028] Block 48 represents "select starting program". The test software starts from a basic unwinding and stretching procedure pre-existing in the machine software, to compare these data with the test data. Block 49 represents the "unwinding and stretching test start". After the starting parameters have been defined, the film unwinding and stretching parameters are defined. Block 50 represents the "unwinding and stretching start". The machine carries out the unwinding and stretching according to the specifications as drawn up. Block 51 represents "stretching stop". The machine is stopped in the position of transverse stretching of the film. Block 52 represents "record data with pocket/PC". The operator must record on the PC or on a dedicated interface system (pocket) the data required by the test program. The following inquiry table may, for example, appear on the screen connected to the PC:

UNWINDING PHASE

[0029] 

Unwinding carried out without rupture

YES/NO

STRETCH PHASE

[0030] 

Stretch carried out without rupture			YES/NO
ruptures in front part	Left □	Centre □	Right □
ruptures in central part	Left □	Centre □	Right □
ruptures in rear part	Left □	Centre □	Right □
End of recording	End of test program

[0031] When the answers YES or NO have been given, and when the boxes indicating the parts of the film affected by any ruptures have been ticked, the program is instructed to proceed with the new processing.

[0032] Block 53 represents "stop machine and remove tested film". The program stops the machine in conditions such that the operator can remove the pre-stretched portion of film on which the test has been performed. Block 54 represents "calculate new operating parameters". According to the data processed previously and the latest data entered with the test, the program calculates the new operating parameters of the machine for the phase in question. Block 55 represents "check sufficient parameters". The program checks whether the data acquired are sufficient to enable the corresponding parameters of the basic program to be processed, for adaptation to the characteristics of the film used. Block 56 is a switch dependent on whether the parameters are sufficient or not. If the parameters are not sufficient, the program moves to block 57, "calculate new unwinding and stretch", whereas if the parameters are sufficient the program moves to block 58, "calculate new program corrective data". In block 57, the program calculates the data which may still be required, prepares the machine for a new phase of unwinding and stretching and the flow returns to block 50. In block 58, the program calculates the final data for the film being tested and for the temperature of the operating environment, and enters these data in task tables. Block 59 is "calculate interpolation of various temperatures". Only if the parameters for the film tested at different temperatures are known, the complete parameters at the different temperatures are calculated with interpolations of the different data recorded. Block 60 represents "store working data". The data are stored in the PC or in a dedicated interface system and are simultaneously recorded in the store of the machine. The data can then be transferred finally from the PC or from the dedicated interface to the EPROM or RAM of all the machines. Block 61 represents "end of program".

[0033] The flow chart in Figure 11 relates to the test of the film for the aforesaid phases b) of back-up and partial closure of the wrapping. The test is conducted with sample trays to be introduced in sequence and according to specific requests of the machine program. Block 62 is "start control program". Block 63 is "select unwinding and stretch program defined by the preceding test". Block 64 represents "select start program". Block 65 represents "supply and raise tray containing product". Block 66 is "stop machine in wrapping phase". Block 67 represents "record data with PC/pocket". Block 68 represents "machine discharges product". Block 69 represents "calculate new working parameters". Block 70 is "check whether the acquired parameters are sufficient for the processing of the program". Block 71 is a switch, dependent on whether "the acquired parameters are sufficient or not". If the answer is negative, the program moves to block 72, "data on new product to be wrapped" and then to block 65. Conversely, if the acquired parameters are sufficient, the program moves to block 73, "calculate new program corrective data", then to block 74, "calculate interpolations for various temperatures", then to block 75, "store working data", and finally to block 76, "end of program".

[0034] The flow chart in Figure 12 relates to tests of the film for the aforesaid phases "c" of complete closure of the film around the tray, cutting of the film and discharge of the packaged product. In this case also, the same sample trays are used as in the preceding test. Block 77 is "start control program". Block 78 is "select unwinding and stretch program" and block 79 is "select back-up and transverse closing program". Block 80 is "select start program". Block 81 is "supply tray containing product, raise it against the film which backs up this raising and whose side flaps are spread under the tray". At block 82, the machine completes the wrapping of the product, cuts the film and discharges the packaged product. At block 83, "the data acquired at block 82 are recorded in the PC/pocket". Block 84 is "calculate new working program". Block 85 is "check whether the data acquired are sufficient". Block 86 is a switch dependent on whether the measured parameters are sufficient or not. If not, the program moves to block 87, "data on new product to be wrapped", and then returns to block 81. If the parameters are sufficient, the program moves instead to block 88, "calculate new program corrective data", then to block 89, "calculate interpolation for various temperatures", then to block 90, "store working data" and then to block 91, "end of program".

[0035] The corrective data for various types of film available on the market may be stored, possibly in advance, in the software of the machine, and each table of data is made to correspond to a specific code number. During the installation of the machine or during operation, when the decision is made to change films or to prepare the machine to operate with a known film, the new table corresponding to the type of film chosen is first selected, as indicated by block 92 of the flow chart in Figure 13 relating to the operating phase of the packaging machine. Block 92 is followed by block 93, for "selection of tray/product program", which allows for the shape and quality of the trays and of the products, and then by phase 94, for "check of operating temperature". In block 95, the program "loads the operating data for a temperature equal or close to the measured ambient temperature" and in the subsequent block 95 it "redefines the operating parameters". In block 97, it "starts the operating cycle", in block 98 "the tray containing the product enters", in block 99 "the calculations are performed according to the operating data" and in block 100 "the packaging movements are synchronized".

Claims

1. Process of wrapping products with stretchable film providing:

- a phase of unwinding a portion of film from a reel and phases of pre-stretching the said film;

- a phase of back-up of the pre-stretched film while the product is raised and forced against the said film;

- one or more phases of spreading and folding flaps of the packaging film under the product, while the film is separated at the correct time by a cut from the reel from which it has been unwound, and the packaged product is discharged from the packaging station;

characterized in that each movement, in each of the said phases, is carried out with a variable speed, with continuous and cyclical variation, with precise accelerations and decelerations, in such a way as to ensure the attainment of the best compromise between the highest rate of execution of the said phases and the greatest use of the stretchability of the film without the yielding and/or rupture of the film used.

2. Process according to Claim 1), in which each movement and the parameters of interpolation of the various movements of the various phases of the method of packaging a product with stretchable film, are conditioned automatically by the following variables:

- the characteristics of size, shape and quality of the product to be wrapped;

- the elongation-yield-rupture curves of the film used;

- the behaviour of the film with the variation of the temperature and humidity of the operating environment;

- the relative speeds of the various simultaneous movements;

- the stresses imparted by the product to the film in the phase of raising the product.

3. Equipment for wrapping products with stretchable film comprising:

- means for unwinding from a reel a portion of stretchable film, whose length is proportional to the dimensions of the product to be wrapped, and means for pre-stretching the said film;

- means for raising the product against the pre-stretched film, while back-up means slacken the tension of the film;

- folding means which at the correct time fold and spread the flaps of the packaging film under the product which, by other means, is pushed to discharge it, while other means cut the said film and separate it from the supply reel;

- electric motors with electronic speed and phase control, for driving all the above mentioned means, said electric motors being controlled by a CPU;

characterized in that the actuators moving the various means mentioned above are driven by the said electric motors, each of which is controlled by an electronic circuit card connected by an appropriate serial link (42) to the master CPU or CPUs (41) of the machine, in order to make the said actuators move with variable speed, with continuous variation and with accelerations and decelerations which make it possible to obtain the best compromise between the maximum speed of movement of the said means and the maximum use of the characteristics of stretchability of the film used, without the yielding or rupture of the said film.

4. Equipment according to Claim 3), in which the processor which controls the operation of the machine is provided with means for modifying the program for driving the motors with variable motion, according to the following variables:

- the characteristics (size, shape and quality) of the product to be wrapped;

- the elongation-yield-rupture curves of the film used;

- the behaviour of the film with the variation of the temperature and humidity of the operating environment;

- the relative speeds of the various simultaneous movements;

- the stresses imparted by the product to the film in the phase of raising the product.

5. Equipment according to Claim 3), in which each card for controlling the variable motion motors of the packaging machine comprises: a movement microprocessor (33) connected by an appropriate serial link to the master CPU of the machine; a power supply (34) which generates the necessary voltages; an EPROM (35) which contains the basic logic and the fixed programs of the system; a RAM (36) to load both the operating parameters and the variable parameters sent from the other microprocessors; a control logic (37); a power unit (38) to drive the motor with an encoder and parking brake (39) if required, and an input/output logic unit (40).

6. Equipment according to Claim 5), in which the card which controls each motor with electronic speed and phase control comprises:

- means for controlling the communication with the other CPU cards, to transmit and receive the operating parameters and programs;

- means for processing the parameters to calculate and execute the required profiles;

- means for controlling the synchronizing signals between the various CPUs in both input and output;

- means for checking and maintaining the synchronization of the movement of the controlled motor with that of the motors controlled by the other cards, by means of the signals from the other controllers;

- means for controlling the execution of the movement of the motor in a correct way or in any case within the tolerances specified by the procedure followed at that moment, an encoder and power factor correction sensors being provided for this purpose and also enabling the movement to be synchronized in the initialization phase;

- means for producing new movements with alternative profiles if the system is unable to execute the required profile within the specified tolerances;

- means for transferring to the master card the new parameters calculated in case of modification of the profile;

- means for supplying new synchronization signals;

- means of automatic adjustment;

- means for test functions.

7. Equipment according to the preceding claims, in which, for the execution of the test relating to the phases of unwinding and stretching, for the automatic adaptation of the operating program of the packaging machine to the use of film of various characteristics, there are provided:

- means (47) for starting the control program;

- means (48) for selecting the starting program;

- means (49) for processing the data for the first phase of unwinding and stretching;

- means (50) for commanding the execution of the phases of unwinding and stretching according to the specifications as drawn up;

- means (51) for stopping the machine in the stretching position;

- means (52) to enable the operator to record on the PC connected to the machine, or on a dedicated interface system, the data required for the test program, particularly to indicate whether and where ruptures or yielding have occurred and then to instruct the program to proceed to the new processing;

- means (53) for stopping the packaging machine in conditions which permit the removal of the stretched and tested film;

- means (54) for making the program calculate the new operating parameters according to the data previously processed and the latest data entered;

- means (55) for checking whether the acquired parameters are sufficient for the re-processing of the program;

- exchange means (56) by which, if the acquired parameters are not sufficient, means (57) connected to the preceding actuating means (50) are activated to calculate a new phase of unwinding and stretching, whereas, if the data acquired are sufficient, means (58) for calculating the corrective data of the new program are activated;

- means (59) for the calculation of the final data for the tested film and for the specific temperature in which the operation is carried out, these being entered in task tables;

- means (60) for storing the data acquired on the PC or on the dedicated interface system and for recording them simultaneously in the store of the machine and means (61) for interrupting the test program.

8. Equipment according to the preceding claims, in which, for the execution of the test relating to the phases of raising the product, back-up of the film and folding the lateral flaps of the film under the product, for the automatic adaptation of the operating program of the packaging machine to the use of films having various characteristics, there are provided:

- means (62) for starting the control program;

- means (63) for selecting the unwinding and stretching program defined by the preceding test and dedicated for this purpose;

- means (64) for selecting the starting program relating to the phase for which the test is to be performed;

- means (65) for commanding the machine to supply and raise the tray containing the product;

- means (66) for stopping the machine in the phase of transverse wrapping of the product;

- means (67) for recording the acquired data by means of the PC or dedicated interface system;

- means (68) for commanding the machine to discharge the product;

- means (69) for calculating the new operating parameters;

- means (70) for checking whether the acquired parameters are sufficient for the processing of the operating program;

- exchange means (71) by which, if the acquired parameters are not sufficient, means are activated to obtain data on a new product to be wrapped, these means then activating the preceding means (65) of supplying and raising the product, whereas, if the data acquired are sufficient, means (73) are activated for calculating the corrective data for the new program;

- means (74) for calculating interpolation at the various temperatures;

- means (75) for storing the operating data and means (76) for interrupting the test program.

9. Equipment according to the preceding claims, in which, for the execution of the test relating to the phases of final closure of the package of the product, of cutting the film and discharge of the packaged product, for the automatic adaptation of the operating program of the packaging machine to the use of films having various characteristics, there are provided:

- means (77) for starting the control program;

- means (78) for selecting the unwinding and stretching program re-adapted by the preceding test;

- means (79) for selecting the back-up and transverse closing program re-adapted by the preceding test;

- means (80) for selecting the starting program;

- means (81) for commanding the machine to supply the tray containing the product and to raise it against the unwound and pre-stretched film, while means slacken the tension of the film and fold the lateral flaps of the said film under the product;

- means (82) for commanding the machine to complete the wrapping of the product, to cut the packaging film and to discharge the packaged product;

- means (83) to record on the PC or on a dedicated interface system the data acquired from the preceding means;

- means (84) for calculating the new operating program;

- means (85) for checking whether the acquired data are sufficient;

- exchange means (86) by which, if the acquired data are not sufficient, means (87) are activated to inform the machine about the characteristics of the new product to be wrapped, after which the machine repeats the packaging cycle on the new product, whereas, if the data acquired are sufficient, means (88) are activated for calculating the corrective data for the new program;

- means (89) for calculation of interpolation at the various temperatures;

- means (90) for storing the acquired operating data, and end-of-program means (91).

10. Equipment according to the preceding claims, in which, for the test phases which require the product to be raised against the pre-stretched film, as in the preceding Claims 8) and 9), sample trays are used as the product and are introduced in sequence when this is specifically requested by the machine program.

11. Equipment according to the preceding claims, characterized in that it comprises means for reading into the software of the packaging machine the corrective data for various types of film available on the market, and means for making each table of data correspond to a specific code number, means (92) being provided which, when the machine is to be prepared for operation with a known type of film, enable the table relating to the selected type of film to be selected, after which the following means are activated:

- means (93) which permit the selection of the program for the tray/product on which the operation is to be executed;

- means (94) for checking the operating temperature;

- means (95) for having the data relating to the temperature equal or close to the measured ambient temperature loaded into the operating program of the packaging machine;

- means (97) for starting the operating cycle;

- means (98) for supplying into the machine the product to be packaged;

- means (99) for executing the calculations according to the operating data;

- means (100) for synchronizing the various movements of the packaging machine according to the operating program calculated by the preceding means.

Ansprüche

1. Verfahren zum Verpacken von Gegenständen mit dehnbarer Folie, mit:

- einem Schritt, in dem ein Folienabschnitt von einer Rolle abgewickelt wird und Schritten, in denen die Folie vorgedehnt wird;

- einem Schritt, in dem die vorgedehnte Folie entlastet wird, während der Gegenstand angehoben und gegen die Folie gedrückt wird;

- einem oder mehreren Schritten, worin Lappen der Verpackungsfolie ausgebreitet und unter den Gegenstand gefaltet werden, während die Folie zum richtigen Zeitpunkt durch einen Schnitt von der Rolle getrennt wird, von der sie abgewickelt wurde, und der verpackte Gegenstand aus der Verpackungsstation ausgestoßen wird,

dadurch gekennzeichnet, daß jede Bewegung in jedem der Schritte mit veränderlicher Geschwindigkeit mit kontinuierlichen und zyklischen Veränderungen und präzisen Beschleunigungen und Verzögerungen in einer Art durchgeführt wird, daß sichergestellt ist, daß der beste Kompromiß zwischen der höchsten Durchführungsrate der Schritte und besten Ausnutzung der Dehnbarkeit der Folie erreicht wird, ohne daß die verwendete Folie nachgibt und/oder reißt.

2. Verfahren nach Anspruch 1, worin jede Bewegung und die Interpolationsparameter der verschiedenen Bewegungen der verschiedenen Schritte des Verfahrens zum Verpacken eines Gegenstands mit dehnbarer Folie automatisch durch die folgenden Variablen bestimmt werden:

- die Eigenschaften von Größe, Form und Qualität des zu verpackenden Gegenstandes;

- die Dehnungs-Festigkeits-Zerreiß-Kurven der verwendeten Folie;

- das Verhalten der Folie bei Veränderung der Temperatur und Feuchtigkeit der Betriebsumgebung;

- die Relativgeschwindigkeiten der verschiedenen, simultanen Bewegungen;

- die von dem Gegenstand auf die Folie ausgeübten Spannungen in der Anhebephase des Gegenstands.

3. Vorrichtung zum Verpacken von Gegenständen mit dehnbarer Folie mit:

- Mitteln zum Abwickeln eines Folienabschnitts von einer Rolle, dessen Länge proportional zu den Abmessungen des zu verpackenden Gegenstandes ist, und Mitteln zum Vor-Dehnen der Folie;

- Mitteln zum Anheben des Gegenstandes gegen die vorgedehnte Folie, wobei Entlastungsmittel die Spannung der Folie abschwächen;

- Mittel zum Falten und Ausbreiten der Lappen der Verpackungsfolie zum richtigen Zeitpunkt unter den Gegenstand, der von anderen Mitteln für den Auswurf verschoben wird, während weitere Mittel die Folie abschneiden und von der Versorgungsrolle trennen;

- elektrischen Motoren mit elektronischer Geschwindigkeits- und Phasenregelung bzw. -steuerung für den Antrieb der vorgenannten Mittel und Einrichtungen, die von einer CPU gesteuert bzw. geregelt sind;

dadurch gekennzeichnet, daß die die diversen oben genannten Mittel bewegenden Antriebe von den elektrischen Motoren betätigt werden, von denen jeder mittels einer elektronischen Schaltungskarte gesteuert bzw. geregelt wird, die über eine geeignete serielle Verbindung (42) mit der Haupt-CPU oder den CPUs (41) der Maschine verbunden ist, um die Antriebe dazu zu bringen, sich mit veränderlicher Geschwindigkeit, mit fortdauernden Veränderungen und mit Beschleunigungen und Verzögerungen zu bewegen, die es ermöglichen, einen bestmöglichen Kompromiß zwischen maximaler Bewegungsgeschwindigkeit der Mittel und bestmöglicher Ausnutzung der Eigenschaften der Dehnbarkeit der verwendeten Folie zu erreichen, ohne die Folie zu überdehnen oder zu zerreißen.

4. Vorrichtung nach Anspruch 3, worin der den Betrieb der Maschine kontrollierende Prozessor mit Mitteln versehen ist, um das Programm für den Antrieb der Motoren mit veränderlicher Bewegung entsprechend der nachfolgenden Variablen zu modifizieren:

- den Eigenschaften von Größe, Form und Qualität des zu verpackenden Gegenstandes;

- den Dehnungs-Festigkeits-Zerreiß-Kurven der verwendeten Folie;

- dem Verhalten der Folie bei Veränderung der Temperatur und Feuchtigkeit der Betriebsumgebung;

- der Relativgeschwindigkeiten der verschiedenen, simultanen Bewegungen;

- der von dem Gegenstand auf die Folie ausgeübten Spannungen in der Anhebephase des Gegenstands.

5. Vorrichtung nach Anspruch 3, worin jede Karte zum Steuern bzw. Regeln der veränderbaren Bewegungsmotoren der Verpackungsmaschine aufweist: einen über eine geeignete serielle Verbindung mit der Haupt-CPU der Maschine verbundenen Bewegungs-Mikroprozessor; eine Stromversorgung (34), die die erforderlichen Spannungen erzeugt; einen EPROM (35), der die Grundschaltung und die gleichbleibenden Programme des Systems enthält; einen RAM (36) zum Einlesen sowohl der Betriebsparameter als auch der veränderlichen Parameter, die von den anderen Mikroprozessoren ausgegeben werden; eine zentrale Logik (37); eine Leistungseinheit (38) zum Antrieb des Motors mit einem Kodiergerät und ggf. einer Feststellbremse; und eine Eingangs-/Ausgangs-Logikeinheit.

6. Vorrichtung nach Anspruch 5, worin die jeden Motor mit elektronischer Geschwindigkeits- und Phasensteuerung bzw. -regelung steuernde bzw. regelnde Karte aufweist:

- Mittel zum Steuern bzw. Regeln der Kommunikation mit den anderen CPU-Karten, um die Betriebsparameter und Programme zu übermitteln und zu empfangen;

- Mittel zum Verarbeiten der Parameter zum Errechnen und Ausführen der benötigten Profile;

- Mittel zum Steuern bzw. Regeln der Synchronisiersignale zwischen den verschiedenen CPUs sowohl beim Ein- als auch beim Ausgang;

- Mittel zum Überprüfen und Erhalten der Synchronisierung der Bewegung des gesteuerten bzw. geregelten Motors mit denen der von anderen Karten kontrollierten Motoren mit Hilfe der von den anderen Regel- bzw. Steuergeräten ausgegebenen Signale;

- Mittel zum Überwachen der Ausführung der Bewegung des Motors in vorschriftsmäßiger Weise oder jedenfalls innerhalb der von der momentan ablaufenden Prozedur vorgegebenen Toleranzen, wozu ein Kodiergerät und Leistungsfaktor-Korrektursensoren vorgesehen sind, und die eine Synchronisierung der Bewegung in der Initialisierunsphase erlauben;

- Mittel zum Erstellen neuer Bewegungsabläufe mit alternativen Profilen für Fälle, in denen das System nicht in der Lage ist, das geforderte Profil innerhalb der gesetzten Toleranzen auszuführen;

- Mittel zum Übertragen der im Falle einer Modifikation des Profils errechneten neuen Parameter an die Master-Karte;

- Mittel, um neue Synchronisierungssignale auszugeben;

- Einstellmittel;

- Mittel für Testfunktionen.

7. Vorrichtung nach einem der vorangegangenen Ansprüche, bei der für die Durchführung des die Schritte Abwickeln und Dehnen betreffenden Tests für die automatische Adaption des Betriebsprogramms der Verpackungsmaschine zur Verwendung von Folien mit verschiedenen Eigenschaften vorgesehen sind:

- Mittel (47) zum Starten des Kontrollprogramms;

- Mittel (48) zum Auswählen des Startprogramms;

- Mittel (49) zum Verarbeiten der Daten für den ersten Schritt des Abwickelns und Dehnens;

- Mittel (50), um die Ausführung der Schritte des Abwickelns und Dehnens entsprechend den ausgezogenen Vorgaben zu veranlassen;

- Mittel (51) zum Anhalten der Maschine in der Dehnstellung;

- Mittel (52), um den Betreiber in die Lage zu versetzen, am mit der Maschine verbundenen PC oder einem dafür bestimmten Schnittstellensystem die erforderlichen Daten für das Testprogramm aufzuzeichnen, insbesondere um anzuzeigen, ob und wo Risse oder Überdehnungen aufgetreten sind und dann das Programm anzuweisen, mit einem weiteren Prozeß fortzufahren;

- Mittel (53) zum Anhalten der Verpackungsmaschine in Zuständen, die ein Entfernen der gedehnten und getesteten Folie erlauben;

- Mittel (54), die das Programm veranlassen, die neuen Betriebsparameter nach den zuvor bearbeiteten Daten und den zuletzt eingegebenen Daten zu berechnen;

- Mittel (55) zum Überprüfen, ob die erhaltenen Parameter ausreichen, um das Programm erneut durchlaufen zu lassen;

- Austauschmittel (56), mit deren Hilfe im Falle von nicht ausreichend erhaltenen Parametern Mittel (57) aktiviert werden, die an die vorerwähnten Betätigungsmittel (50) angeschlossen sind, um einen neuen Schritt des Abwickelns und Dehnens zu berechnen, wobei, wenn die ermittelten Daten ausreichend sind, Mittel (58) zum Berechnen von Korrekturdaten des neuen Programms aktiviert werden;

- Mittel (59) zum Berechnen der endgültigen Daten für die geprüfte Folie und für die spezifische Temperatur, bei der die Operation ausgeführt wird, wobei diese Daten in Auftragstabellen eingetragen werden;

- Mittel (60) zum Speichern der ermittelten Daten in einem PC oder auf einem dafür bestimmten Schnittstellensystem und zu ihrem gleichzeitigen Aufzeichnen im Speicher der Maschine und Mittel (61) zum Unterbrechen des Testprogramms.

8. Vorrichtung nach einem der vorangegangenen Ansprüche, bei der für die Durchführung des die Schritte Anheben des Gegenstands, Entspannen der Folie und Falten der seitlichen Folienlappen unter den Gegenstand betreffenden Tests für die automatische Adaption des Betriebsprogramms der Verpackungsmaschine zur Verwendung von Folien mit verschiedenen Eigenschaften vorgesehen sind:

- Mittel (62) zum Starten des Kontrollprogramms;

- Mittel (63) zum Auswählen des Abwickel- und Dehnprogramms, wie es durch den vorangegangen Test festgelegt und für diesen Zweck bestimmt wurde;

- Mittel (64) zum Auswählen des Startprogramms, das den Schritt betrifft, für den der Test durchgeführt werden soll;

- Mittel (65), um der Maschine zu befehlen, das den Gegenstand enthaltende Tablett einzuführen und anzuheben;

- Mittel (66) zum Anhalten der Maschine beim Schritt des seitlichen Verpackens des Gegenstands;

- Mittel (67) zum Aufzeichnen der ermittelten Daten mit Hilfe des PCs oder vorgesehenen Schnittstellensystems;

- Mittel (68) zum Anweisen der Maschine, den Gegenstand auszustoßen;

- Mittel (70) zum Überprüfen, ob die ermittelten Parameter ausreichend für die Durchführung des Programms sind;

- Austauschmittel (71), mittels derer im Falle von nicht in ausreichendem Maße erfaßten Parametern Mittel aktiviert werden, um Daten für einen neuen zu verpackenden Gegenstand zu erhalten, wobei diese Mittel dann die vorerwähnten Mittel (65) zum Zuführen und Anheben des Gegenstandes aktivieren, wobei bei ausreichend ermittelten Daten Mittel (73) in Gang gesetzt werden, um die Korrekturdaten für das neue Programm zu berechnen.

9. Vorrichtung nach einem der vorangegangenen Ansprüche, bei der für die Durchführung des die Schritte abschließendes Verschließen der Folie und Ausstoßen des verpackten Gegenstands betreffenden Tests für die automatische Adaption des Betriebsprogramms der Verpackungsmaschine zur Verwendung von Folien mit verschiedenen Eigenschaften vorgesehen sind:

- Mittel (77) zum Starten des Kontrollprogramms;

- Mittel (78) zum Auswählen des Abwickel- und Dehnprogramms, wie es durch den vorangegangen Test neu festgelegt wurde;

- Mittel (79) zum Auswählen des Entspann- und Seitlich-Schließ-Programms , wie es durch den vorangegangen Test neu festgelegt wurde;

- Mittel (80) zum Auswählen des Startprogramms;

- Mittel (81), um der Maschine zu befehlen, das den Gegenstand enthaltende Tablett einzuführen und gegen die abgewickelte und vorgedehnte Folie anzuheben, während Mittel die Spannung der Folie verringern und die seitlichen Folienlappen unter den Gegenstand falten;

- Mittel (82), um der Maschine zu befehlen, das Verpacken des Gegenstandes zu vervollständigen, die Folie abzutrennen und den verpackten Gegenstand auszustoßen;

- Mittel (83) zum Aufzeichnen der von den vorstehenden Mitteln ermittelten Daten in einem PC oder einem dafür bestimmten Schnittstellensystem;

- Mittel (84) zum Berechnen eines neuen Betriebsprogramms;

- Mittel (85) zum Überprüfen, ob die ermittelten Daten ausreichend sind;

- Austauschmittel (86), mit deren Hilfe bei nicht ausreichend ermittelten Daten Mittel (87) aktiviert werden, um die Maschine von den Eigenschaften des zu verpackenden Gegenstandes in Kenntnis zu setzen, wonach die Maschine den Verpackungszyklus mit dem neuen Gegenstand wiederholt, wobei, wenn die erfaßten Daten ausreichen, Mittel (88) in Gang gesetzt werden, um die Korrekturdaten für das neue Programm zu berechnen;

- Mittel (89) zum Berechnen von Interpolationen bei verschiedenen Temperaturen;

- Mittel (90) zum Speichern der ermittelten Betriebsdaten und Programm-Ende-Mittel (91).

10. Vorrichtung nach einem der vorangegangenen Ansprüche, bei der für die Testdurchläufe, die es erforderlich machen, daß der Gegenstand gegen die vorgedehnte Folie entsprechend den vorstehenden Ansprüchen 8. und 9. angehoben wird, Mustertabletts als Gegenstand verwendet und nacheinander eingeführt werden, wenn dies ausdrücklich von dem Maschinenprogramm gefordert wird.

11. Vorrichtung nach einem der vorangegangenen Ansprüche, gekennzeichnet durch Mittel zum Einlesen der Korrekturdaten für verschiedene am Markt erhältliche Folientypen in die Software der Verpackungsmaschine, und durch Mittel, um jede Datentabelle einer bestimmten Codenummer zuzuweisen, wobei Mittel (92) vorgesehen sind, die bei der Vorbereitung der Maschine für den Betrieb mit einer bekannten Folientype es ermöglichen, daß die der ausgewählten Folientype entsprechende Tabelle ausgewählt wird, wonach die nachstehenden Mittel aktiviert werden:

- Mittel (93), die die Auswahl des Programms für das Tablett/den Gegenstand erlauben, womit der Betrieb ausgeführt werden soll;

- Mittel (94) zum Überprüfen der Betriebstemperatur;

- Mittel (95), um die Daten, die sich auf die Temperatur beziehen, die gleich oder annähernd gleich zu der gemessenen Umgebungstemperatur ist, in das Betriebsprogramm der Verpackungsmaschine zu laden;

- Mittel (97) zum Starten des Betriebszyklus;

- Mittel (98) zum Zuführen des zu verpackenden Gegenstandes in die Maschine;

- Mittel (99) zum Ausführen der Berechnungen gemäß den Betriebsdaten;

- Mittel (100) zum Synchronisieren der verschiedenen Bewegungen der Verpackungsmaschine entsprechend dem von den vorstehenden Mitteln errechneten Betriebsprogramm.

Revendications

1. Procédé pour envelopper des produits de film étirable comprenant :

- une phase de déroulement d'un tronçon de film d'une bobine et des phases de préétirage du film ;

- une phase d'appui du film préétiré alors que le produit est soulevé et appliqué à force sur le film ;

- une phase ou plusieurs phases de déploiement et de pliage de flans du film d'emballage sous le produit, alors que le film est séparé, au bon moment par une coupure, de la bobine duquel il est déroulé et le produit emballé est déchargé du poste d'emballage ;

   caractérisé en ce que chaque mouvement dans chacune desdites phases est effectué à une vitesse variable, avec une variation continue et cyclique, avec des accélérations et des décélérations précises, de façon à assurer le compromis le meilleur possible entre la vitesse d'exécution la plus grande desdites phases et l'utilisation la plus grande de l'étirabilité du film sans atteindre la limite élastique et/ou la rupture du film utilisé.

2. Procédé suivant la revendication 1, dans lequel chaque mouvement et les paramètres d'interpolation des divers mouvements des diverses phases du procédé d'emballage d'un produit par du film étirable sont conditionnés automatiquement par les variables suivantes :

- les caractéristiques de dimension, forme et qualité du produit à envelopper ;

- la courbe allongement-limite élastique-rupture du film utilisé ;

- le comportement du film lorsque la température et l'humidité ambiante varient ;

- les vitesses relatives des divers mouvements simultanés ;

- les contraintes imparties par le produit au film dans la phase où le produit est soulevé.

3. Equipement pour envelopper des produits de film étirable comprenant :

- des moyens pour dérouler d'une bobine un tronçon de film étirable, de longueur proportionnelle aux dimensions du produit à envelopper, et des moyens pour préétirer le film ;

- des moyens pour soulever le produit contre le film préétiré, tandis que des moyens d'appui diminuent la tension du film ;

- des moyens de pliage qui, au bon moment, plient et déploient les flans du film d'emballage sous le produit qui, par d'autres moyens, est poussé en vue d'être déchargé, tandis que d'autres moyens coupent le film et le séparent de la bobine d'alimentation ;

- des moteurs électriques à commande électronique de vitesse et de phase pour entraîner tous les moyens mentionnés ci-dessus, les moteurs électriques étant commandés par une unité centrale de traitement ;

   caractérisé en ce que les actionneurs déplaçant les divers moyens mentionnés ci-dessus sont entraînés par les moteurs électriques, chacun d'eux étant commandé par une carte électronique de circuit connectée par une liaison (42) série appropriée à l'unité centrale de traitement maître ou aux unités centrales de traitement (41) maîtres de la machine, de manière à faire en sorte que les actionneurs se déplacent à une vitesse variable avec une variation continue et avec des accélérations et des décélérations qui rendent possibles d'obtenir le compromis le meilleur possible entre la vitesse maximum de déplacement des moyens et l'utilisation maximum des caractéristiques d'étirabilité du film utilisé sans atteindre la limite élastique ni la rupture du film.

4. Equipement suivant la revendication 3, dans lequel le processeur qui commande le fonctionnement de la machine est muni de moyens de modification du programme d'entraînement des moteurs à mouvement variable en fonction des variables suivantes :

- les caractéristiques (dimension, forme et qualité) du produit enveloppé ;

- les courbes allongement-limite d'élasticité-rupture du film utilisé ;

- le comportement du film lorsque la température et l'humidité ambiante varient ;

- les vitesses relatives des divers mouvements simultanés ;

- les contraintes imparties par le produit au film dans la phase où le produit est soulevé.

5. Equipement suivant la revendication 3, dans lequel chaque carte de commande des moteurs à déplacement variable de la machine d'emballage comprend : un microprocesseur (33) de mouvement relié par une liaison série appropriée à l'unité centrale de traitement maître de la machine ; une source (34) d'alimentation en courant qui engendre les tensions nécessaires ; une EPROM (35) qui contient la logique de base et les programmes fixés du système ; une RAM (36) pour charger à la fois les paramètres de fonctionnement et les paramètres variables envoyés par les autres microprocesseurs ; une logique (37) de commande ; une unité (38) de puissance pour entraîner le moteur ayant un codeur et un frein (39) d'arrêt si nécessaire, et une unité (40) logique d'entrée/sortie.

6. Equipement suivant la revendication 5, dans lequel la carte qui commande chaque moteur ayant une commande électronique de vitesse et de phase comprend :

- des moyens pour commander la communication avec les autres cartes d'unité centrale de traitement, pour transmettre et recevoir les paramètres de fonctionnement et les programmes ;

- des moyens de traitement des paramètres pour calculer et exécuter les profils requis ;

- des moyens de commande des signaux de synchronisation entre les diverses unités centrales de traitement à la fois en entrée et en sortie;

- des moyens pour vérifier et maintenir la synchronisation du mouvement du moteur commandé avec ceux des moteurs commandés par les autres cartes au moyen des signaux provenant des autres dispositifs de commande ;

- des moyens pour commander l'exécution du mouvement du moteur d'une façon correcte ou en tout cas dans les tolérances précisées par la procédure suivie à cet instant, un codeur et des capteurs de correction de facteur de puissance étant prévus à cet effet et permettant également de synchroniser le mouvement dans la phase d'initialisation ;

- des moyens pour produire de nouveaux mouvements ayant d'autres profils si le système est incapable d'exécuter le profil requis dans les tolérances précisées ;

- des moyens pour transférer à la carte maître les nouveaux paramètres calculés dans le cas d'une modification du profil ;

- des moyens pour envoyer de nouveaux signaux de synchronisation ;

- des moyens d'ajustement automatique ;

- des moyens de fonctions de test.

7. Equipement suivant les revendications précédentes, dans lequel, pour l'exécution du test relatif aux phases de déroulement et d'étirage pour l'adaptation automatique du programme de fonctionnement de la machine d'emballage à l'utilisation de film ayant des caractéristiques diverses, il est prévu :

- des moyens (47) pour faire commencer le programme de commande ;

- des moyens (48) pour sélectionner le programme initial ;

- des moyens (49) pour traiter les données de la première phase de déroulement et d'étirage ;

- des moyens (50) pour ordonner l'exécution des phases de déroulement et d'étirage suivant les spécifications arrêtées ;

- des moyens (51) pour arrêter la machine en la position d'étirage;

- des moyens (52) pour permettre à l'opérateur d'enregistrer sur l'ordinateur relié à la machine ou sur un système d'interface dédié des données requises pour le programme de test, en particulier pour indiquer si et ou il s'est produit des ruptures ou des atteintes de la limite élastique, puis pour instruire le programme de procéder au nouveau traitement ;

- des moyens (53) pour arrêter la machine d'emballage dans un état qui permet d'enlever le film étiré et testé ;

- des moyens (54) pour faire que le programme calcule les nouveaux paramètres de fonctionnement suivant les données préalablement traitées et les dernières données entrées ;

- des moyens (55) pour vérifier si les paramètres acquis sont suffisants pour le retraitement du programme ;

- des moyens (56) d'échange par lesquels, si les paramètres acquis ne sont pas suffisants, des moyens (57) reliés aux moyens (50) d'actionnement précédents sont activés pour calculer une nouvelle phase de déroulement et d'étirage, tandis que, si les données acquises sont suffisantes, des moyens (58) pour calculer les données de correction du nouveau programme sont activés ;

- des moyens (59) pour le calcul des données finales pour le film testé et pour la température précise à laquelle l'opération est effectuée, celles-ci étant entrées dans des tables de tâches ;

- des moyens (60) pour mémoriser les données acquises sur l'ordinateur ou sur le système d'interface dédié et pour les enregistrer simultanément dans la mémoire de la machine et des moyens (61) pour interrompre le programme d'essai.

8. Equipement suivant les revendications précédentes, dans lequel, pour l'exécution du test relatif aux phases d'élévation du produit, d'appui du film et de pliage des flans latéraux du film sous le produit, pour l'adaptation automatique du programme de fonctionnement de la machine d'emballage à l'utilisation des films ayant diverses caractéristiques, il est prévu :

- des moyens (62) pour faire démarrer le programme de commande;

- des moyens (63) pour sélectionner le programme de déroulement et d'étirage défini par le test précédent et dédié à cet effet ;

- des moyens (64) pour sélectionner le programme de démarrage relatif à la phase pour laquelle on doit effectuer le test ;

- des moyens (65) pour ordonner à la machine d'envoyer et de soulever la barquette contenant le produit ;

- des moyens (66) pour arrêter la machine dans la phase d'enveloppement transversal du produit ;

- des moyens (67) pour enregistrer les données acquises à l'aide de l'ordinateur ou du système d'interface ;

- des moyens (68) pour ordonner à la machine de décharger le produit ;

- des moyens (69) pour calculer les nouveaux paramètres de fonctionnement ;

- des moyens (70) pour vérifier si les paramètres acquis sont suffisants pour le traitement du programme de fonctionnement ;

- des moyens (71) d'échange par lesquels, si les paramètres acquis ne sont pas suffisants, des moyens sont activés pour obtenir des données sur un nouveau produit à envelopper, ces moyens activant ensuite les moyens (65) précédents d'alimentation et de soulèvement du produit, tandis que, si les données acquises sont suffisantes, des moyens (73) sont activés pour calculer les données de correction pour le nouveau programme ;

- des moyens (74) pour calculer une interpolation aux diverses températures ;

- des moyens (75) pour mémoriser les données de fonctionnement et des moyens (76) pour interrompre le programme d'essai.

9. Equipement suivant les revendications précédentes, dans lequel, pour l'exécution du test relatif aux phases de fermeture finale de l'emballage du produit, de coupe du film et de déchargement du produit emballé, pour l'adaptation automatique du programme de fonctionnement de la machine d'emballage à l'utilisation de films ayant des caractéristiques diverses, il est prévu :

- des moyens (77) pour faire démarrer le programme de commande;

- des moyens (78) pour sélectionner le programme de déroulement et d'étirage réadapté par le test précédent ;

- des moyens (79) pour sélectionner le programme d'appui et de fermeture transversale réadapté par le test précédent ;

- des moyens (80) pour sélectionner le programme de démarrage;

- des moyens (81) pour ordonner à la machine d'envoyer la barquette contenant le produit et de la soulever contre le film non déroulé et préétiré, tandis que des moyens diminuent la tension du film et plient les flans latéraux du film sous le produit ;

- des moyens (82) pour ordonner à la machine de compléter l'enveloppement du produit, de couper le film d'emballage et de décharger le produit emballé ;

- des moyens (83) pour enregistrer sur l'ordinateur ou sur un système d'interface dédié les données acquises à partir des moyens précédents;

- des moyens (84) pour calculer le nouveau programme de fonctionnement ;

- des moyens (85) pour vérifier si les paramètres acquis sont suffisants ;

- des moyens (86) d'échange par lesquels, si les données acquises ne sont pas suffisantes, des moyens (87) sont activés pour informer la machine des caractéristiques du nouveau produit à envelopper, après quoi la machine répète le cycle d'emballage sur le nouveau produit, tandis que si les données acquises sont suffisantes, des moyens (88) sont activés pour calculer les données de correction pour le nouveau programme ;

- des moyens (89) pour calculer une interpolation aux diverses températures ;

- des moyens (90) de mémorisation des données acquises de fonctionnement et des moyens (91) de fin de programme.

10. Equipement suivant les revendications précédentes, dans lequel, pour les phases d'essai qui exigent de soulever le produit contre le film préétiré, comme dans les revendication 8 et 9 précédentes, des barquettes échantillons sont utilisées comme produits et sont introduites en séquence quand cela est requis spécifiquement par le programme de la machine.

11. Equipement suivant les revendications précédentes, caractérisé en ce qu'il comprend des moyens pour lire dans le logiciel de la machine d'emballage les données de correction pour divers types de films disponibles sur le marché et des moyens pour faire que chaque table de données correspond à un nombre de code précis, des moyens (92) étant prévus, lorsque la machine doit être préparée pour fonctionner avec un type connu de film, permettant de sélectionner la table relative au type sélectionné de film, après quoi les moyens suivants sont activés :

- des moyens (93) qui permettent de sélectionner le programme pour la barquette/produit sur lequel doit être effectuée l'opération ;

- des moyens (94) pour vérifier la température de fonctionnement;

- des moyens (95) pour faire en sorte que les données relatives à la température soient égales ou proches de la température ambiante mesurée chargée dans le programme de fonctionnement de la machine d'emballage ;

- des moyens (97) pour faire commencer le cycle de fonctionnement ;

- des moyens (98) pour alimenter la machine en le produit à emballer ;

- des moyens (99) pour exécuter les calculs suivant les données de fonctionnement ;

- des moyens (100) pour synchroniser les divers mouvements de la machine d'emballage suivant le programme de fonctionnement calculé par les moyens précédents.

Drawing