PACKAGING MACHINE WITH FOIL TRANSPORT DEVICE AND METHOD

Abstract

A packaging machine may include a foil transport device and a controlling system for controlling an operation of at least one drive unit of the foil transport device. The controlling system is designed to activate the drive unit during a production run of the packaging machine on the basis of a speed- and/or temperature-dependent friction moment characteristic curve detected by means of a rotationally driven measurement run carried out by the drive unit. The disclosure furthermore relates to a method for controlling a drive unit of a foil transport device.

Claims

1. A packaging machine, comprising: a foil transport device including a drive unit; and a controlling system for controlling an operation of the drive unit of the foil transport device, wherein the controlling system is designed to activate the drive unit during a production run of the packaging machine based on a speed- and/or temperature-dependent friction moment characteristic curve detected by means of a rotationally driven measurement run carried out by the drive unit.

2. The packaging machine according to claim 1, wherein the drive unit includes a servo drive.

3. The packaging machine according to claim 1, wherein the drive unit is activatable, for detecting the friction moment characteristic curve over a total speed range of the drive unit.

4. The packaging machine according to claim 3, wherein the drive unit is activatable to speed levels continuously increasing in steps to detect the friction moment characteristic curve.

5. The packaging machine according to claim 1, wherein the drive unit is activatable to speed levels continuously increasing in steps to detect the friction moment characteristic curve.

6. The packaging machine according to claim 1, wherein the controlling system is designed to determine a measurement run temperature of the drive unit rotationally driven during the measurement run.

7. The packaging machine according to claim 6, wherein the controlling system is configured to determine, based on a friction moment-temperature characteristic curve stored to the controlling system for the drive unit, a temperature compensation factor for the activation of the drive unit which is derived therefrom in view of a currently detected operating temperature of the drive unit and in view of the measurement run temperature detected during the measurement run.

8. The packaging machine according to claim 1, wherein the packaging machine is a deep-drawing packaging machine or a tray sealer.

9. The packaging machine according to claim 1, wherein the foil transport device includes a further drive unit, the controlling system being designed to activate the further drive unit during a production run of the packaging machine based on a speed- and/or temperature-dependent friction moment characteristic curve detected by means of a rotationally driven measurement run carried out by the further drive unit.

10. A method for controlling a drive unit of a foil transport device which supplies, at a packaging machine during a production run taking place thereat, a foil with a predetermined foil tension to a workstation of the packaging machine, wherein the drive unit is controlled, during the production run of the packaging machine, based on a speed- and/or temperature-dependent friction moment characteristic curve detected by means of a rotationally driven measurement run carried out by the drive unit.

11. The method according to claim 10, wherein a controlling system determines, based on a friction moment-temperature characteristic curve stored to the controlling system for the drive unit, a temperature compensation factor for activation of the drive unit in view of an operating temperature of the drive unit currently detected during the production run, and in view of a measurement run temperature detected during the measurement run.

12. The method according to claim 11, wherein the controlling system derives a power supply of the drive unit for achieving a desired foil tension from the detected friction moment characteristic curve during the production run and dynamically adapts the power supply by means of the temperature compensation factor determined in view of the current operating temperature.

13. The method according to claim 10, wherein the drive unit is rotated into both directions during a predetermined running-in interval before the measurement run.

14. The method according to claim 13, wherein the drive unit is accelerated in steps during a measurement section of the measurement run performed after the running-in interval with a continuously increasing speed for determining the friction moment characteristic curve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The disclosure will be described more in detail with reference to the following figures. In the drawing:

[0044] FIG. 1 shows a schematic side view of a packaging machine embodied as a deep-drawing packaging machine;

[0045] FIG. 2 shows a perspective representation of a packaging machine present as a tray sealer;

[0046] FIG. 3 shows a measurement run or friction detection run for a drive unit of a foil transport device of the packaging machine; and

[0047] FIG. 4 shows a friction moment-temperature characteristic curve for determining a temperature compensation factor.

[0048] Equal components are always provided with equal reference numerals in the figures.

DETAILED DESCRIPTION

[0049] FIG. 1 shows, in a schematic side view, a packaging machine 1 embodied as an intermittently operating deep-drawing packaging machine 2. This deep-drawing packaging machine 2 includes a shaping station 3, a sealing station 4, a cross cutter 5, and a longitudinal cutter 6 which are arranged in this order at a machine frame 7 in a direction of transport R. At the entry side, a feed roller 8 is located at the machine frame 7, a lower foil 9 being reeled off from said roller. Furthermore, the deep-drawing packaging machine 2 includes a transport chain 11, in particular transport chains or clamp chains 11, respectively, arranged at both sides, which grips the lower foil 9 and transports it further in the direction of transport R per main cycle.

[0050] In the represented embodiment, the shaping station 3 is embodied as a deep-drawing station in which troughs M are formed into the lower foil 9 by deep-drawing, for example by means of compressed air and/or a vacuum. The shaping station 3 can be designed such that several troughs M are formed next to each other in the direction perpendicular to the direction of transport R. In the direction of transport R downstream of the shaping station 3, a filling section 10 is provided in which the troughs M formed in the lower foil 9 are filled with products.

[0051] The sealing station 4 has a hermetically closable chamber 4a in which the atmosphere in the troughs M is e.g., evacuated and/or can be replaced by a replacement gas or a gas mixture by gas flushing before they are sealed with the upper foil 30 discharged by an upper foil transport device 12.

[0052] The transverse cutter 5 can be embodied as a stamping machine which cuts through the lower foil 9 and the upper foil 30 in a direction transverse to the direction of transport R between adjacent troughs M. In the process, the transverse cutter 5 operates such that the lower foil 9 is not cut through across its total width, but is not cut through at least in an edge region. This permits a controlled further transport through the transport chain 11.

[0053] The longitudinal cutter 6 can be embodied as a knife arrangement by which the lower foil 9 and the upper foil 30 are cut through between adjacent troughs M and at the lateral edge of the lower foil 9 in the direction of transport R so that singled packages V are provided downstream of the longitudinal cutter 6.

[0054] The deep-drawing packaging machine 2 furthermore includes a controlling system 13. The latter has the task of controlling and monitoring the processes running in the deep-drawing packaging machine 2. A display device 14 with operational controls 15 serves to visualize or influence the process operations in the deep-drawing packaging machine 2 for or by an operator.

[0055] FIG. 2 shows a tray sealing machine 16. This is also referred to as a tray sealer by experts. Package bowls S are provided at the tray sealer 16 on a feed belt 17. The tray sealer 16 has a gripper device 18 by means of which the package bowls S provided on the feed belt 17 are picked up and transferred to a lower sealing tool part 19 of the sealing station 20 for a tray sealing operation. During the tray sealing operation, the lower sealing tool part 19 is lifted against an upper sealing tool part 21 positioned above it to seal the package bowls S with an upper foil 22 guided through the sealing station 20. Via the upper sealing tool part 21 and/or the lower sealing tool part 19, a gas treatment process can be performed before the tray sealing operation to produce a desired atmosphere within the package bowls S positioned in the sealing station 20. After the tray sealing operation, the sealing station 20 is opened by lowering the lower sealing tool part 19. Now, the packages sealed with a desired atmosphere can be picked up by means of the gripper device 18 and transferred to a discharge belt 23.

[0056] The tray sealer 16 of FIG. 2 has a controlling system 24. The latter has the task of controlling and monitoring the processes running in the deep-drawing packaging machine 16.

[0057] At the packaging machines shown in FIG. 1 and in FIG. 2, that means at the deep-drawing packaging machine 2 and at the tray sealer 16, it is advantageous to supply the respective foils to the respective workstations with a certain constant foil tension reproducible per machine cycle.

[0058] In the deep-drawing packaging machine 1, a lower foil transport device 26 is employed for this as a foil transport device 25a in the entry of the deep-drawing packaging machine 1. The lower foil transport device 26 comprises a drive unit 27. The controlling system 13 is configured to control an operation of the drive unit 27. By means of the drive unit 27 and by means of an activation of a further, non-depicted drive unit of the transport chains 11, the lower foil 9 can be supplied to the shaping station 3 with a desired foil tension for the shaping process taking place therein.

[0059] Furthermore, FIG. 1 shows, as the foil transport device 25b, the upper foil transport device 12 which includes a drive unit 28 to supply the upper foil 30 to the sealing station 4 with a desired foil tension. The upper foil transport device 12 can be activated by means of the controlling system 13 such that the upper foil 30 is supplied to the sealing station 4 with the desired foil tension. The drive unit 28 of the upper foil transport device 12 can here be activated in a manner coordinated with the transport chains 11 to achieve the desired foil tension in the upper foil 30.

[0060] In FIG. 2, as the foil transport device 25c, a further upper foil transport device 29 is provided which is configured to supply the upper foil 22 to the sealing station 20 with a desired foil tension. The upper foil transport device 29 shown in FIG. 2 has a drive unit 31 which can be activated by means of the controlling system 24. The tray sealer 16 furthermore has a remainder foil winder 42 which winds up the upper foil 22 remaining after the sealing process. The drive unit 31 and a drive unit 32 of the remainder foil winder 42 can be activated by means of the controlling system 24 for a controlled foil transport with a desired foil tension.

[0061] FIG. 3 shows a speed diagram which is performed by means of one of the drive units 27, 28, 31, 32 shown or not shown in FIGS. 1 and 2. The speed diagram of FIG. 3 shows a running-in interval 33. During the running-in interval 33, the drive unit 27, 28, 31, 32 is moved in both directions to remove an adhesion effect. Subsequently, a measurement run 34 takes place. During the measurement run 34, the drive unit 27, 28, 31, 32 is accelerated in steps over its total speed range. By means of the measurement run 34 performed in this manner, the own friction of the drive unit 27, 28, 31, 32 can be determined for the respective speed steps. The measurement run 34 thus represents a friction detection run for the respective drive units 27, 28, 31, 32.

[0062] FIG. 3 shows that during the measurement run 34, speed steps that become increasingly larger are carried out. Along the constant velocity plateaus 40 arising therefrom, the friction moment of the drive units 27, 28, 31, 32 resulting for it can be detected. Here, the respective friction moment is directly proportional to a power supply employed for the respective velocity plateau 40 whose progression is shown in FIG. 3 below the speed curve.

[0063] Above all, FIG. 3 shows that directly at the beginning of the measurement run 34 during the switching to the first velocity plateau 40, at the drive unit 27, 28, 31, 32, a transition 35 between a static friction and a sliding friction can be measured. This transition 35 is shown in FIG. 3 by the increase of the intensity of current between the running-in interval 33 and the measurement run 34.

[0064] FIG. 3 furthermore shows, in the current progression represented therein, that an increase in the speed at the beginning of the velocity plateau 40 leads to peak powers 41 in the power supply. The peak powers 41 provoked at the respective velocity plateaus 40 at the beginning by the controlled speed increase then, however, flatten with a constant speed. By means of the power supply values occurring during the measurement run 34 for the velocity plateaus 40 and which are substantially smoothed, a friction moment characteristic curve 38 (see FIG. 4) can be determined by means of the controlling system 13, 24.

[0065] FIG. 4 shows a friction moment-temperature characteristic curve 36 which can be, for example, stored for one of the drive units 27, 28, 31, 32, or for one of the above-mentioned, other drive units of the controlling system 13, 24.

[0066] By means of the friction moment-temperature characteristic curve 36 shown in FIG. 4, a temperature compensation factor 37 can be determined for the corresponding drive unit 27, 28, 31, 32. The temperature compensation factor 37 forms a quotient from a torque which is depicted by means of the friction moment-temperature characteristic curve 36 for a currently measured operating temperature of the drive unit 27, 28, 31, 32, and from a friction moment which is present in the friction moment-temperature characteristic curve 36 at the temperature at which the measurement run 34 of FIG. 3 has been carried out.

[0067] By means of the temperature compensation factor 37, it is possible to adapt the speed required for a desired foil tension of FIG. 3, that means the power supply assumed for this based on the friction moment characteristic curve 38, in view of the current operating temperature of the drive unit 27, 28, 31, 32, so that during the production run, a constant foil tension can be achieved even at varying operating temperatures of the drive unit 27, 28, 31, 32.

[0068] In FIG. 4, the friction moment from the friction moment-temperature characteristic curve 36 for an operating temperature of 15° C. is determined by way of example, which is, according to FIG. 4, approximately 6 Nm. It is furthermore assumed that the measurement run 34 of FIG. 3 has been performed at a measurement run temperature of 5° C. The friction moment-temperature characteristic curve 36 of FIG. 4 indicates a friction moment of 9 Nm for 5° C., so that the quotient from the respective friction moments is ⅔.

[0069] FIG. 4 furthermore shows the only schematically represented friction moment characteristic curve 38 which is accomplished by means of the measurement run 34, i.e., depending on the power supply of the drive unit 27, 28, 31, 32 required for this and shown in FIG. 3. On the basis of the friction moment characteristic curve 38, for the drive unit 27, 28, 31, 32, the controlling system 13, 24 can determine a power supply 38' compensated for the operating temperature 15 measured during the production run using the temperature compensation factor 37, by means of which the drive unit 27, 28, 31, 32 can be operated to maintain the foil tension constant at an operating temperature of 15° C. Here, the assumed power supply resulting from the measurement run 34 for the speed to achieve the foil tension is corrected by the temperature compensation factor 37.

[0070] FIGS. 3 and 4 show that a power supply that can be derived from the measurement run 34 to achieve a certain desired foil tension in view of an operating temperature of the drive unit 27, 28, 31, 32 changing during the production run, provoked by the running operation of the drive unit 27, 28, 31, 32, can be adapted by means of the calculable temperature compensation factor 37 to calculate the power supply of the drive unit 27, 28, 31, 32 actually required for the detected operating temperature which is necessary for achieving a constant and reproducible foil tension.

[0071] As one skilled in the art would understand, the controlling systems 13, 24, and any other controller, system, or subsystem 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 for performing the particular algorithms represented by the various functions and/or operations described herein, including interaction between and/or cooperation with each other. 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).