EP2368825B2 - Device for controlling coils with coiled film material - Google Patents

Description

The present invention relates to a packaging machine with a device for checking spools with wound film material. The coil comprises a core on which the film material is wound. Furthermore, a sensor arrangement is assigned to the coil, by means of which one end of the film material on the coil can be identified.

As in the German patent application DE 10 2008 020 299 A1 disclosed, a packaging machine comprises two reels of wound film material. One of the two reels is always a supply reel, which then supplies film material to the packaging process for the objects to be packaged if the film material wound on the active reel runs out. For environmental and cost reasons, it is necessary to use the film material on the active coil to such an extent that it is unwound as far as possible down to the core. The end of the film on the active reel must be indicated so that the second reel (reserve reel) can be introduced into the packaging process, in order to make the film material wound on it available for the packaging process.

As in the Krones AG company brochure about the fully automatic "Vario Pack Pro" packaging machine, a packaging machine for a wide range of applications is disclosed. Here the bottles entering the packaging machine are separated into groups. The foils used to wrap the individual groups are pulled off an active spool. The groups are then wrapped in the film and then run through a shrink tunnel. The individual foil blanks are separated from the foil material drawn from the reel with a cutting knife according to the required length for the wrapping of the objects. The second reel, which is also assigned to the packaging machine, is then included in the packaging process when the film wound on the first reel is running out.

The German Offenlegungsschrift DE 40 21 402 A1 describes a device for controlling emptying coils. This device is mainly used in wrapping machines for articles. The relevant control device consists essentially of detection means which work in the area of a feed station for the tape at a wrapping station and / or in the vicinity of a group of reel and support shaft arranged in the area of the station. These detection means serve to detect a predetermined value of an electrical impedance that is generated by the group of coil and / or support shaft and / or determine functions of at least one radial dimension of the group of coil and support shaft. For this purpose, the device sits on the spool and moves with decreasing thickness of the foil material wound on the spool in the direction of the core or the axis of the spool in order to deduce from the measured signals the amount of foil material that is still on the Bobbin is wound.

The German Offenlegungsschrift DE 195 43 246 discloses an apparatus for controlling spools for wrapping machines. The web material (film material) is wound on a reel for the wrapping machines. The coil has a corresponding core around which the foil material is wound. The spool rotates around its own axis of rotation in order to make the film material wound on it available to the wrapping machine. An optoelectronic and light-sensitive sensor is assigned to the reel, which sensor can be moved along a substantially radial direction of the reel itself during the unwinding of the reel. The sensor is used to detect the value of a chromatic property of a region of the coil and to send a signal to the scanning device of a color shade corresponding to a previously entered sample value. The film material, which is rolled up directly on the core of the spool, is colored so that the sensor registers a different color value of the film when the end of the film material on the spool approaches and thus indicates the end of the film material on the respective active coil.

the US patent application 2008/0142631 A1 discloses a system and method that indicates the supply of paper to a printer. The paper is rolled up around a core on a spool. The core has a fixed diameter. The paper rolled up on the core decreases in diameter over the life of the paper being used by the printer. A scanning device is provided which determines the core diameter and the paper diameter. A signal is output when the length of the paper material rolled onto the core falls below a certain threshold value.

The European patent application EP 2 093 172 A2 describes a paper supply for a printer, in which the paper supply is arranged on at least one spool. The paper supply includes at least two differently arranged receptacles for the spools, so that different sizes of the paper spools can be processed with the printer. An adjustable end sensor is provided for end detection of the paper that is wound on a core. The adjustability makes it possible to adjust the sensor to the respective position of the coil.

The Japanese patent application JP 600 12 449 A describes a device for end detection of a film material which is rolled up on a spool. For this purpose, a magnetic strip is introduced across the width of the film material, which is located in the vicinity of the end of the film material. When the film material is unrolled from the spool, a detector detects this magnetic strip, which in turn marks the end of the film material on the spool indicates.

Furthermore, in Japanese patent application JP 61 08 63 55 A an arrangement is described with which a connection point or the end of long film-like material can be detected. The connection point runs across the film web and is detected by two photo sensors. The photo sensors are arranged in the direction of transport of the film material.

The German Offenlegungsschrift DE 44 42 154 describes a method for initiating a premature bobbin change. For this purpose, a non-contact temperature measurement is provided at the front. On the basis of the measured temperature in the vicinity of the core of the bobbin, one can infer the amount of paper that is still on the bobbin or that has already been wound onto the bobbin.

The European patent application EP 0 730 960 A2 describes a method and a device for determining the end of film material rolled up on a spool. For this purpose, at least two strips are provided on the film material across the film material, which are detected by a corresponding sensor device. In one embodiment, the sensor device consists of a light source and a correspondingly assigned photodetector. The strips that indicate the amount of film material still rolled onto the core are detected by means of the sensor device.

The German Offenlegungsschrift DE 198 47 466 A1 describes a method and a device for detecting defects in unwindable plastic webs. The sensor is attached to a lever arm that moves in the direction of the core depending on the film material unwound from the spool. The sensor detects marking elements that are attached to the film material and protrude laterally from the face of the film material.

The U.S. Patent 6,059,222 discloses a method for determining the tension of a paper web being withdrawn from a roll. For this purpose, a signal that controls the drive motor of the roller is supplied to a control device from an angle sensor arrangement which comprises several magnets and Hall sensors. The control makes it possible to maintain a predefined tension even when the paper material is decreasing on the roll.

The object of the invention is to create a packaging machine with which the end of the film material on the reel in the packaging machine can be detected inexpensively, cost-efficiently, safely and independently of parameters of the film material wound on a reel.

The above object is achieved by a packaging machine which comprises the features of claim 1.

In the packaging machine, the film material is wound onto a core of a reel. The end of the film material on the reel can be detected with a sensor arrangement. The sensor arrangement is designed in such a way that it comprises at least one optoelectronic sensor. The optoelectronic sensor is arranged in a stationary manner in relation to an end face of the coil. The sensor is designed in such a way that part of the end face of the rotating coil can be optically detected.

The optoelectronic sensor is arranged in relation to the coil in such a way that the part of the outer circle of the rotating coil detected by the optoelectronic sensor comprises the core and the film material immediately following the core.

According to a further embodiment, the optoelectronic sensor is arranged in relation to the coil in such a way that the part of the end face of the rotating coil detected by the optoelectronic sensor creates a possible air gap between the mandrel and the core, the core itself and the one directly following the core Includes sheet material.

The optoelectronic sensor is a line sensor that detects part of the outer circle of the core of the rotating coil without additional lighting. A control is also provided with which a control signal is generated if a height of the film material wound on the core, registered by the optoelectronic sensor, falls below a predetermined threshold value.

In addition to the optoelectronic sensor, the sensor arrangement can have a capacitive sensor. The capacitive sensor is arranged so that it can move radially in relation to the coil. The radial height in relation to the coil can be measured by means of the capacitive sensor. A control is also provided with which a control signal can be generated if the radial height of the film material wound on the core, registered by the capacitive sensor, falls below a predetermined threshold value.

The controller can be designed in such a way that a combined or common control signal is only output if the height registered by the optoelectronic sensor and the radial height registered by the capacitive sensor fall below the predetermined threshold value.

The advantages of the invention emerge in the packaging machine for creating containers from articles. As already mentioned at the beginning, two reels with wound film material are assigned to a packaging machine. One of the two coils is always the active coil. In order not to interrupt the production process of the containers for unnecessarily long, it is necessary to identify the end of the film on the active reel. When determining the end of the foil material on the spool, make sure that the foil material is used up as much as possible. You want to avoid replacing the spool too early and thus producing waste of foil material, which one could actually still use for the packaging of containers. When the end of the film or the approaching end of the film material on the reel is detected, a signal is output and a change is made to the supply reel.

The outer edge (circular arc) of the foil core and the outer diameter of the foil reel are detected by means of the optoelectronic sensor (line sensor), which is fixedly positioned at the front in the direction of the foil reel. A defined, one-time programmed value specifies the minimum distance (threshold value) of the diameter of the foil reel, from which a signal is output that indicates the end of the foil material on the reel. If this threshold value is not reached, a signal is sent to the machine control that the film material on the active reel has been used up. The invention has the advantage that a reliable detection of the end of the film material on the coil can be determined regardless of the diameter of the core of the coil.

Figur 1

zeigt einen schematischen Aufbau einer Verpackungsmaschine, wie diese bereits aus dem Stand der Technik bekannt ist.

Figur 2

zeigt eine Vorrichtung zum Bestimmen des Endes von Folienmaterial auf einer Spule, gemäß dem Stand der Technik.

Figur 3

zeigt schematisch eine Seitenansicht der Folienspule mit dem zugeordneten optoelektronischen Sensor.

Figur 4

zeigt eine Stirnansicht der Folienspule mit dem zugeordneten optoelektronischen Sensor.

Figur 5

zeigt eine Detailansicht des durch den optoelektronischen Sensor registrierten Bereichs um den Kern der Spule.

Figur 6

zeigt einen kapazitiven, in radialer Richtung zur Folienspule beweglichen Sensor, der zusammen mit dem optoelektronischen Sensor das Ende des Folienmaterials auf der Spule ermittelt.

In the following, exemplary embodiments are intended to explain the invention and its advantages in more detail with reference to the accompanying figures. The proportions of the individual elements to one another in the figures do not always correspond to the real proportions, since some forms are simplified and other forms are shown enlarged in relation to other elements for better illustration.

Figure 1

shows a schematic structure of a packaging machine as it is already known from the prior art.

Figure 2

shows a device for determining the end of sheet material on a spool, according to the prior art.

Figure 3

shows schematically a side view of the film coil with the associated optoelectronic sensor.

Figure 4

shows a front view of the film coil with the associated optoelectronic sensor.

Figure 5

shows a detailed view of the area registered by the optoelectronic sensor around the core of the coil.

Figure 6

shows a capacitive sensor which can be moved in the radial direction to the film reel and which, together with the optoelectronic sensor, determines the end of the film material on the reel.

Identical reference symbols are used for identical or identically acting elements of the invention. Furthermore, for the sake of clarity, only reference symbols are shown in the individual figures that are necessary for the description of the respective figure. The illustrated embodiments merely represent examples of how the packaging machine can be designed and do not represent a final limitation.

Figure 1 shows a schematic view of a packaging machine 100 according to the prior art. The individual groups 101 of objects 102 are wrapped with a foil blank 105. The foil blanks 105 are made available by at least one spool 10 made of foil material 12. In the in Figure 1 The embodiment shown, two coils 10 made of film material 12 are provided. In this case, a coil 10 is the active coil 10A, which means that the film material 12 is drawn off from this coil for the wrapping of the groups 101 of the objects 102. The supply reel 10V is used when the foil material 12 on the active reel 10A is running low. It should be possible to switch from the active coil 10A to the supply coil 10V as smoothly as possible.

Figure 2 shows a sensor arrangement 2 according to the prior art, by means of which one end of the film material 12 on the spool 10 can be detected. The sensor arrangement 2 consists of a light source 20 which is designed as a laser. The light source 20 emits a light beam 21 which arrives at a detector 22. The light beam 21 only reaches the detector 22 when a certain amount of the film material 12 has been pulled off the spool 10. The film material 12 is wound on a core 8. In Figure 2 the situation is shown that the film material 12 _{1 is} pulled from the almost full spool 10 of film material 12. In this situation, the light beam 21 is blocked by the film material 12 which is rolled up on the spool 10. If a certain amount of the film material 12 has been unrolled from the spool 10, which is identified by the reference number 12 ₂ , the light beam 21 passes the circumference of the film material 12 still on the core 8 and reaches the detector 22. A signal from the detector 22 can now which indicates the end of the sheet material 12 on the spool 10. A disadvantage of this arrangement of the prior art is that, depending on the diameter D of the core 8, the end of the film material on the spool 10 is not reliably detected. Thus, on the one hand, the situation can arise that with a large diameter D of the film core 8, the end of the film material 12 on the spool 10 is not even recognized. However, if the diameter D of the core 8 is small, the light beam 21 already reaches the detector 22 when there is still sufficient film material 10 wound on the core 8 of the spool 10 that can still be used for wrapping the article. In this case, a lot of film material 12 that can still be used will be thrown away unnecessarily.

Figure 3 shows a schematic representation of the assignment of the sensor arrangement 2 to a coil 10 made of film material 12. The film material 12 is open a core 8 of a coil 10 is wound. The coil 10 is seated on a mandrel 4 which can be rotated about an axis 6. The sensor arrangement 2 consists of the in Figure 3 The embodiment shown consists of an optoelectronic sensor 14. The optoelectronic sensor 14 is connected to a controller 5.
The line sensor 14 is arranged opposite an end region 7 of the coil 10. The line sensor 14 has a detection area 15 (see Figure 5 ) and the line sensor 14 is arranged in a stationary manner with respect to the rotating bobbin 10. The arrangement of the line sensor 14 and its detection area 15 are designed such that both the core 8 of the coil 10 and at least part of the film material 12 rolled onto the core 8 come to lie in the detection area 15 of the line sensor 14.

Figure 4 shows an end view of the spool 10 with the film material 12 rolled up on the core 8. Figure 4 shows that the optoelectronic sensor 14 (or line sensor) is arranged in relation to the end face 7 of the coil 10 in such a way that at least the core 8 and part of the film material 12 rolled onto the core 8 is detected. At the in Figure 4 The embodiment shown, the optoelectronic sensor 14 is designed such that a detection area 15 of the optoelectronic sensor 14 extends from the mandrel 4 of the coil 10 to far beyond the core 8 of the coil 10. With this arrangement, it is possible to detect the removal of the film material 12 on the spool 10. The in Figure 4 The dashed circle shown represents an outer circle 18 of the film material 12, which is still present on the spool 10 at a certain processing time. With the embodiment of the optoelectronic sensor 14 shown here, it is already possible to detect the decrease in film material 12 on the spool 10 over time. It is also possible with the optoelectronic sensor 14 to detect a potential air gap 25 between the mandrel 4 and an inner circle 8 _{I of} the core 8 of the coil 10. If the remainder of the film material 12 remaining on the core 8 of the spool 10 has reached a predefined height H relative to an outer circle 8 _{A of} the core 8, this is registered by the optoelectronic sensor 14 and a corresponding signal is output to the controller 5.

Figure 5 shows the section 16 or the signal image of the section 16 of the end face 7 of the rotating coil 10, which the optoelectronic sensor 14 detects. The optoelectronic sensor 14 is arranged in relation to the end face 7 of the coil 10 in such a way that in the detection area 15 of the optoelectronic sensor 14 (line sensor) at least both a part of the core 8 and a part of the film material 12 rolled up on the coil 10 are closed come to lie.

Figure 5 shows the signal image of the section 16 of the optoelectronic sensor 14 as shown in FIG Figure 4 is arranged. The optoelectronic sensor 14 detects a part 17 of the outer circle 18 (see Figure 4 ) the amount of film material 12 on the spool 10, which changes over time. The change in a distance D _T1 , D _{T2 over time} is shown in FIG Figure 5 indicated by the dashed arrow 30. It is also possible with this arrangement of the optoelectronic sensor 14 to detect a part 17 of the outer circle 18 of the film material 12 rolled up on the core 8. When the film material 12 rolled up on the core 8 approaches the end, the part 17 of the outer circle 18 determines the predefined height H, which finally indicates the end of the film material 12 rolled up on the core 8. The distance between the part 17 of the outer circle 18 of the film material 12 reaches the predefined height H, which indicates the near end of the film material 12. Furthermore, a part 19 _{A of} the outer circle 8 _A and a part 19 _{I of} the inner circle 8 _{I of} the core 8 can also be detected. If an air gap 25 forms between the core 8 and the mandrel 4, this can also be detected with the optoelectronic sensor 14, since with this embodiment of the arrangement of the optoelectronic sensor 14 it is possible to create the air gap 25 between the core 8 and the mandrel 4 to capture. _{In addition to changing a distance D T1} , D _{T2 of} the outer circle 18 of the film material 12 over time, the optoelectronic sensor 14 also performs a security function, so that a possible malfunction can be indicated. In addition to the outer circle 18 of the decreasing film material 12, the outer circle 8 _{A of} the core 8, the inner circle 8 _{I of} the core 8, the optoelectronic sensor 14 now also detects the air gap 25 between the core 8 and the mandrel 4 be programmed so that, as a safety function, in addition to the time-decreasing distance D _T1 , D _{T2 of} the foil material to the outer circle 8 _{A of} the core 8, the absolute diameter of the core 8 and foil material 12 on the spool 10 can be queried and set accordingly by the controller 5 .

Figure 6 shows a further embodiment for determining the amount of the film material 12 present on the spool 10. The sensor arrangement 2 is designed as a capacitive sensor 25. The capacitive sensor 25 lies lightly on the film material 12 rolled up on the spool 10 or is at least arranged in the immediate vicinity of the film material 12. The capacitive sensor 25 can be moved radially with respect to the core 8 of the coil 10. With the capacitive sensor 25, the radial height R of the film material 12 located on the core 8 of the coil 10 can be detected. The capacitive sensor 25 migrates depending on the film material 12 withdrawn from the spool 10 closer in the direction of the core 8. The capacitive sensor 25 also outputs a signal to the controller 5 when the capacitive sensor 25 registers a radial height R that is below a predetermined threshold.

The capacitive sensor 25 serves as an additional means to the optoelectronic sensor 14, which determines the remaining height H of the film material on the core 8. If the capacitive sensor 25 and the optoelectronic Sensor 14 deliver a signal to the controller 5, it can be assumed that the end of the film material 12 on the core 8 has been reached or a reel change is necessary in order to ensure the continuous operation of the machine which is consuming the film material 12. The optoelectronic sensor 14 then outputs a signal when the height H of the film material 12 on the core 8 falls below a certain threshold value. In parallel, the capacitive sensor 25 outputs a signal when the radial height R of the film material 12 on the core falls below a predefined threshold value. This additional protection by the capacitive sensor 25 makes the determination of the end of the film material 12 on the reel 10 more reliable.

It goes without saying for a person skilled in the art that the capacitive sensor 25 provides additional security for determining the end of the film material 12 on the reel. For the determination of the end of the film material 12 on the spool 10, however, the optoelectronic sensor 14 alone is completely sufficient.

Claims (9)

1. A packaging machine (100) comprising a device (1) for controlling a reel (10) of wound film material (12) wound on a core (8) of the reel (10) and a sensor assembly (2) by means of which an end of the film material (12) on the reel (10) can be detected,
   characterized in that
   the sensor assembly (2) comprises at least one optoelectrical sensor (14) which is stationary with respect to an end face (7) of the rotating reel (10) placed on a dome (4) and is formed such that a part of the end face (7) of the rotating reel (10) can be optically detected,
   wherein the optoelectronic sensor (14) is a line sensor which detects a part (19A) of the outer circumference (8A) of the core (8) of the rotating reel (10) without additional illumination.
2. The packaging machine (100) according to claim 1, wherein the optoelectronic sensor (14) is arranged with respect to the reel (10) such that the part of the end face (7) of the rotating reel detected by the optoelectronic sensor (14) comprises a potential air gap (25) between the dome (4) and the core (8), the core (8) itself and the film material (12) immediately adjacent the core (8).
3. The packaging machine (100) according to claims 1 to 2, wherein a controller (5) is provided with which a control signal can be generated if a height (H) sensed by the optoelectronic sensor (14) between the outer circumference (8A) of the core (8) and an outer circumference (18) of the film material (12) wound onto the core (8) decreases below a predetermined threshold value.
4. The packaging machine (100) according to claims 1 to 3, wherein the optoelectronic sensor (14) is programmable in such a way that the outer circumference (18) of the decreasing film material (12), the outer circumference (8A) of the core (8), the inner circumference (81) of the core (8) and/or the air gap (25) between the core (8) and the dome (4) can be detected.
5. The packaging machine (100) according to claim 4, wherein the optoelectronic sensor (14) fulfils a safety function and also detects a distance (DT1, DT2) between the film material (12) and the outer circumference (8A) of the core (8) decreasing with time and the absolute diameter of core (8) and film material (12) on the reel (10).
6. The packaging machine (100) according to claims 1 to 5, wherein the sensor assembly (2) additionally comprises a capacitive sensor (25) which is configured radially movable with respect to the reel (10).
7. The packaging machine (100) according to claim 6, wherein the radial height (R) of the film material (12) located on the core (8) of the reel (10) can be detected by means of the capacitive sensor (25).
8. The packaging machine (100) according to claims 6 and 7, wherein a controller (5) is provided with which a control signal can be generated if the radial height (R) of the film material (12) wound onto the core (8) sensed by the capacitive sensor (25) decreases below a predetermined threshold value.
9. The packaging machine (100) according to Claims 3 or 6, wherein the controller (5) is configured such that a common control signal can be output only if the height (H) sensed by the optoelectronic sensor (14) and the radial height (R) sensed by the capacitive sensor (25) decrease below the predetermined threshold value.

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