EP4271648A1

EP4271648A1 - Device and method for closing a container by means of a screw closure

Info

Publication number: EP4271648A1
Application number: EP22700055.1A
Authority: EP
Inventors: Markus Schoenfelder; Maximilian Landstorfer; Lutz Kampmann; Simon Gebendorfer; Daniel Ludwig
Original assignee: Krones AG
Current assignee: Krones AG
Priority date: 2021-01-04
Filing date: 2022-01-04
Publication date: 2023-11-08
Also published as: WO2022144459A1; CN116783138A; DE102021100028A1

Abstract

The present invention relates to a device (1) for closing a container (8) by means of a screw closure (11), preferably for closing a beverage container by means of a screw closure (11) in a beverage packaging plant (5), the device comprising: a container holder (3) for holding a container (8) to be closed; and a closing unit (2), which can be moved in an application direction (12) relative to the container holder (3), wherein the closing unit (2) comprises an electric motor (13) for applying a torque (M) in the application direction (12) to a screw closure (11) received by the closing unit (2); and an open-loop/closed-loop control device (4), for open-loop/closed-loop control of the electric motor (13), wherein the open-loop/closed-loop control device (4) is designed to control the electric motor (13) in an open-loop/closed-loop manner such that a plurality of successive torque impulses (P) of a specified level (MP) can be applied to the screw closure (11). The invention also relates to a corresponding method.

Description

Device and method for closing a container with a screw cap

technical field

The present invention relates to a device and a method for closing a container with a screw cap, for example for closing a beverage container with a screw cap in a beverage bottling plant.

State of the art

It is known to close containers with a screw cap. For this purpose it is known to provide mechanical systems for controlling the screwing of the screw cap onto the container or onto its container mouth.

Mechanical systems offer no possibility of feedback or process monitoring with regard to the angle of rotation of the screw cap or with regard to the torque applied to the screw cap. In addition, mechanical systems only allow a fixed torque curve that is predetermined by their physical design.

In order to address the aforementioned disadvantages, devices are known which have an electric motor, for example a servo motor, for applying the screwing torque to the screw cap. Such a device and a corresponding method can be found in EP 2 203 377 B1. With the appropriate control, the speed, direction of rotation and torque can be changed or adapted to the respective application. Thus, when changing from the processing of containers of a first type to the processing of containers of another type, a modification or conversion of the device can be reduced compared to mechanical systems or even omitted entirely. This leads to shorter cleaning times in aseptic applications, for example. Presentation of the invention

Proceeding from the known prior art, it is an object of the present invention to provide an improved device for closing a container with a screw cap, preferably for closing a beverage container with a screw cap in a beverage bottling plant, and a corresponding method.

The object is achieved by a device for closing a container with a screw cap, preferably for closing a beverage container with a screw cap in a beverage bottling plant, with the features of claim 1. Advantageous developments result from the dependent claims, the description and the figures.

Accordingly, a device for closing a container with a screw cap, preferably for closing a beverage container with a screw cap in a beverage bottling plant, is proposed, comprising a container holder for holding a container to be closed and a closing unit that can be displaced in an application direction relative to the container holder, wherein the closing unit has an electric motor for applying a torque about the direction of application to a screw cap received by the closing unit, and a control/regulating device for controlling/regulating the electric motor. According to the invention, the control/regulating device is set up to control/regulate the electric motor in such a way that the screw cap can be subjected to a plurality of successive torque pulses of a predetermined level.

Due to the fact that the control/regulating device is set up to control/regulate the electric motor in such a way that the screw cap can be subjected to a plurality of successive torque pulses of a predetermined level, an improved sealing result can be achieved compared to conventional devices. Corresponding to the multiple application of the torque pulses with the specified level, it can be achieved that the closing torque of the screw cap at the end of the capping cycle corresponds particularly precisely to a specified value. In other words, the plurality of successive torque pulses of a predetermined magnitude correspond to a repeated application of a torque impact to the screw closure. Accordingly, the effect of an "electronic ratchet" can be provided by the plurality of consecutive torque pulses. The plurality of consecutive torque pulses corresponds to here the repeated retightening of the screw cap up to a specified torque or up to a torque of a specified amount in Nm.

In an alternative view, this electronic ratchet can also be regarded as a kind of torque wrench.

Correspondingly, the proposed device can reduce the probability of incorrect closures in comparison to conventional devices, so that the percentage of containers with incorrectly closed closures that are rejected is lower.

Furthermore, the proposed device can be used to ensure that the desired unscrewing torque for the respective container closure is achieved independently of any short-term resistance during the screwing-on process - for example due to adhesions or irregularities or tolerances in the shape and dimensioning of the thread on the container mouth or in the closure so that a product-safe closure is achieved.

According to a preferred embodiment, the control/regulating device is set up to provide for the application of the plurality of successive torque pulses to the screw cap when a predetermined condition of a process of screwing the screw cap onto the container is reached, and/or to provide for the device to be switched off in response to a switch-off command.

According to a further preferred embodiment, the predetermined condition of the screwing-on process corresponds to reaching a predetermined angle of rotation of the electric motor and/or the screw cap.

Alternatively or additionally, the specified condition of the screwing process can correspond to the achievement of a specified final torque, with the first torque pulse of the plurality of torque pulses preferably corresponding to the achievement of the final torque.

The control/regulating device is preferably designed to determine the angle of rotation, preferably by means of an angle of rotation sensor.

Alternatively or additionally, the control/regulation device can be designed to determine the torque curve of the electric motor, preferably based on the determination of a Actual current value of the electric motor, the control/regulating device preferably being designed to control/regulate the electric motor as a function of the angle of rotation.

According to a further preferred embodiment, the predefined level of at least the first torque pulse corresponds to a predefined final torque of a screwing-on process. The further pulses can then be applied at different and/or variable and, for example, lower torques.

The number of torque pulses can preferably be set, with the plurality of torque pulses preferably corresponding to at least 2, 3, 4, 5, 6, 7 or 8 torque pulses.

According to a further preferred embodiment, a predetermined pulse duration is provided between two consecutive torque pulses, with the pulse duration preferably being the same between all of the respective consecutive torque pulses.

The pulse duration is preferably adjustable, with the pulse duration preferably being 10 ms to 0.1 s, particularly preferably 20 ms to 70 ms, particularly preferably 40 ms to 60 ms and very particularly preferably 50 ms.

According to a further preferred embodiment, each torque pulse is followed by a torque drop of a predetermined level, with the torque drop preferably corresponding to 10% to 40%, particularly preferably 20% to 35%, very particularly preferably 25% to 30% of the predetermined level of the torque pulses, or the torque drop corresponds to a complete drop to zero. In other words, a surging load or a surging torque curve can be provided by the plurality of torque pulses and the torque drop provided in between.

Alternatively, the torque drop can be greater than the specified magnitude of the torque pulses. In other words, each torque pulse is followed by a load change, and therefore a change to a torque that is negative in relation to the sign of the torque pulses. The level of the negative torque is preferably 2% to 10% of the predetermined level of the torque pulses.

It has been found to be advantageous if the control/regulation device is set up in such a way that at least the torque pulses following the first torque pulse are applied suddenly and/or the control/regulation device is set up in such a way that the curve of the increase in torque increases exponentially or linearly or obeying another increasing function at least in the torque pulses following the first torque pulse before a torque pulse.

The object set above is also achieved by a method for closing a container with a screw cap, preferably for closing a beverage container with a screw cap in a beverage bottling plant, with the features of claim 8. Advantageous developments of the method result from the dependent claims and the present description and the figures.

Accordingly, a method for closing a container with a screw cap, preferably for closing a beverage container with a screw cap in a beverage bottling plant, is proposed, comprising lowering a screw cap onto a container to be closed in an application direction, applying a torque about the application direction to the screw cap . According to the invention, the screw cap is subjected to a plurality of successive torque pulses of a predetermined magnitude.

The advantages and effects described with regard to the device can be achieved in an analogous manner by the method.

According to a preferred embodiment, the screw cap is acted upon by the plurality of successive torque pulses when a predetermined condition of a process of screwing the screw cap onto the container is reached, and/or in response to a switch-off command.

According to a further preferred embodiment, the predetermined condition of the screwing-on process corresponds to reaching a predetermined angle of rotation of an electric motor and/or the screw cap. Alternatively or additionally, the predetermined condition of the screwing process corresponds to reaching a predetermined final torque at the end of a process of screwing the screw cap onto the container, with the first torque pulse of the plurality of torque pulses preferably corresponding to reaching the final torque.

Preferably, the angle of rotation of the screw cap or an electric motor providing the torque required for screwing on is determined, preferably by means of a angle of rotation sensor. Alternatively or additionally, the torque curve of the electric motor can be determined, preferably based on the determination of an actual current value of the electric motor, with the electric motor preferably being controlled/regulated as a function of the angle of rotation.

According to a further preferred embodiment, the predetermined level of at least the first torque pulse corresponds to a predetermined final torque of a screwing process. The further pulses can then be applied at different and/or variable and, for example, lower torques.

The number of torque pulses can also advantageously be set, with the plurality of torque pulses preferably corresponding to at least 2, 3, 4, 5, 6, 7 or 8 torque pulses.

According to a further preferred embodiment, a predetermined pulse duration is provided between two consecutive torque pulses, with the pulse duration preferably being the same between all consecutive torque pulses, with the pulse duration preferably being adjustable, with the pulse duration preferably being 10 ms to 0.1 s, particularly preferably 20 ms to 70 ms, particularly preferably 40 ms to 60 ms and very particularly preferably 50 ms.

According to a further preferred embodiment, each torque pulse is followed by a torque drop of a predetermined level, with the torque drop preferably corresponding to 10% to 40%, particularly preferably 20% to 35%, very particularly preferably 25% to 30% of the predetermined level of the torque pulses, or the torque drop corresponds to a complete drop to zero.

Alternatively, the drop in torque can also be greater than 100% of the specified level of the torque pulses, so that the screw closure is subject to alternating loads.

According to a further preferred embodiment, at least the torque pulses following the first torque pulse are applied suddenly. In other words, the course of the increase in torque increases exponentially or linearly or obeying another increasing function, at least in the case of the torque pulses following the first torque pulse before a torque pulse.

Short description of the figures Preferred further embodiments of the invention are explained in more detail by the following description of the figures. show:

FIG. 1 shows a schematic side view of a device for closing a container with a screw cap according to a preferred embodiment;

FIG. 2 shows a schematic top view of a beverage bottling plant, comprising a device according to FIG. 1;

FIG. 3 schematically shows a torque curve for a method for closing a container with a screw cap according to a first embodiment;

FIG. 4 schematically shows a torque curve for a method for closing a container with a screw cap according to a further embodiment;

FIG. 5 schematically shows a torque curve for a method for closing a container with a screw cap according to a further embodiment; and

FIG. 6 schematically shows a torque curve for a method for closing a container with a screw cap according to a further embodiment.

Detailed description of preferred exemplary embodiments

Preferred exemplary embodiments are described below with reference to the figures. Elements that are the same, similar or have the same effect are provided with identical reference symbols in the different figures, and a repeated description of these elements is sometimes dispensed with in order to avoid redundancies.

FIG. 1 shows a schematic side view of a device 1 for closing a container 8 with a screw cap 11 according to a preferred embodiment. The device comprises a container holder 3 for holding the container 8 to be closed and a closing unit 2 that can be displaced in an application direction 12 relative to the container holder 3, the closing unit 2 having an electric motor 13, presently in the form of a servo motor, for applying a torque about the application direction 12 a screw cap 11 accommodated by the capping unit 2 . The screw cap 11 is accommodated in a cap receptacle 14 of the capping unit 2 which is rotatably coupled to the electric motor 13 . The device 1 also includes a control/regulation device 4 for controlling/regulating the electric motor 13, which is set up to control/regulate the electric motor 13 in such a way that the screw cap 11 is subjected to a plurality of successive torque pulses of a predetermined level, as described below in Explained in more detail with regard to FIG.

The screw cap 11 is applied by lowering the closing unit 2 towards the container 8 until the screw cap 11 comes into contact with a thread 10 arranged on the container mouth 9 . The rotary motion introduced via the electric motor 13 onto the closure receptacle 14 causes the screw closure 11 to be screwed onto the thread 10.

As explained in more detail with regard to Figure 3, the control/regulating device 4 is set up to provide for the loading of the screw cap 11 with the plurality of successive torque pulses when a predetermined condition of a screwing process of the screw cap 11 onto the container 8 is reached, which in the present case corresponds to the achievement of the Final torque corresponds to the end of the actual screwing process.

Alternatively, the screw closure 11 can be acted upon by the plurality of successive torque pulses in response to a switch-off command for switching off the device 1 .

The control/regulating device 4 is optionally designed to determine the angle of rotation of the electric motor 13 and/or the screw cap 11, preferably with a rotation angle sensor, not shown here. In addition, the control/regulation device 4 can determine the torque curve of the electric motor 13, in this case based on the determination of an actual current value of the electric motor 13. The control/regulation device 4 can optionally be designed to control/regulate the electric motor 13 as a function of the angle of rotation.

FIG. 2 shows a schematic top view of a beverage bottling plant 5, which includes a capper carousel 6 in a rotary design, on which a multiplicity of devices 1 according to FIG. 1 are arranged.

The closing carousel 6 comprises a closing area 7 in which the closing of the containers 8 by the devices 1 is provided. The sealing area 7 extends in the direction of the table angle <t> of the sealing carousel, seen from a beginning TA of the sealing area 7 to an end TE of the sealing area 7. FIG. 3 shows schematically a torque curve M for a method for closing a container 8 with a screw cap 11 according to a first embodiment, as is used in the device 1 according to FIG. 1 and FIG.

FIG. 3 shows a diagram in which the ordinate shows the torque M in Nm and the abscissa shows the time t in seconds or equivalently the table angle <t> in degrees.

From the starting point in time TA, the screwing of the screw cap 11 onto the thread 10 begins (see FIG. 1). The torque M initially increases successively from the starting point in time TA until it reaches the end torque Mend provided for the closing process. Reaching the final torque Mend corresponds to the end of a conventional screwing process. The screw cap 11 is now subjected to a plurality of successive torque pulses P of a predetermined magnitude Mp, with the first torque pulse P representing the achievement of the final torque Mend.

After the final torque Mend or the first torque pulse P has been reached, the torque curve M experiences a reduction in the amount of a predetermined torque drop AM via the control device 4 . This is followed by a renewed increase in torque M up to the specified level Mp, which represents the next torque pulse P. In the present case, the predefined level Mp of the torque M of a torque pulse P corresponds to the level of the final torque Mend.

As can be seen from FIG. 3, four torque pulses P are provided here as an example. Consequently, at the end of the screwing-on process, the screw cap 11 is subjected to the final torque Mend four times in succession, in each case separated by the interim decrease in the torque M by the torque drop AM.

The number of torque pulses P can preferably be set via the control device 4 .

According to this optional embodiment, the final torque Mend is 1.3 Nm and the torque drop AM is 30% of the specified height Mp of the torque pulses P, and consequently 30% of the final torque Mend.

Every two consecutive torque pulses P are spaced apart from each other by a predetermined pulse duration Tp, with the pulse duration Tp in the present case between each consecutive torque pulses P is equal. According to this embodiment, it is 50 ms.

The time duration of the pulse duration Tp can preferably be set via the control device 4 .

As can be seen from FIG. 3, the torque pulses P following the first torque pulse P are applied almost suddenly. In other words, the progression of the torque increase in the torque pulses P following the first torque pulse P before a torque pulse P is exponential in each case. In a variant that is not shown, the profile can also be designed to increase linearly or be designed to obey another increasing function.

The unscrewing ends at the end time TE.

FIG. 4 schematically shows a torque curve M for a method for closing a container 8 with a screw cap 11 according to a further embodiment. The method essentially corresponds to that described for FIG. 3, in which case, in contrast to the method according to FIG. 3, the torque drop AM is 100% of the specified level Mp. In other words, after each torque pulse P, the screw closure 11 is essentially completely relieved.

Alternatively, the torque drop AM can also be greater than 100% of the specified height Mp of the torque pulses P. Correspondingly, after each torque pulse P, a negative torque is then applied to the screw cap 11, for example at a level of −5% of the specified level Mp of the torque pulses P.

FIG. 5 schematically shows a torque curve M for a method for closing a container 8 with a screw cap 11 according to a further embodiment. The method essentially corresponds to that from FIG. 3, with the torque curve M being designed here in accordance with a screw cap 11 with a guarantee band (not shown). Correspondingly, before reaching the final torque Mend at the end of unscrewing the screw cap 11, the torque curve M has a local maximum MG, which represents a torque that occurs when the guarantee strip of the screw cap 11 is pushed over a ring (not shown) correspondingly provided on the container mouth 9 for fixing the anti-tamper strip occurs, as further detailed in EP 2 203 377 B1.

FIG. 6 shows a schematic of a torque curve M for a method for closing a container 8 with a screw cap 11 according to a further embodiment, which essentially corresponds to that described for FIG the final torque Mend or the specified height Mp of the torque pulses P.

As far as applicable, all of the individual features that are presented in the exemplary embodiments can be combined with one another and/or exchanged without departing from the scope of the invention.

1 device

2 capping unit

3 container holder

4 control/regulator

5 beverage bottling plant

6 capping carousel

7 sealing area

8 containers

9 container mouth

10 threads

11 screw cap

12 direction of application

13 electric motor

14 shutter mount

TA Start time of the sealing area

TE End time of the capping area

<t> table angle

P torque pulse

M torque curve

Mp Default altitude

Mend final torque

MG Local Maximum (Warranty Band Torque)

AM torque drop

Tp pulse duration

Claims

Expectations

1 . Device (1) for closing a container (8) with a screw cap (11), preferably for closing a beverage container with a screw cap (11) in a beverage bottling plant (5), comprising a container holder (3) for holding a container (8 ) and a closing unit (2) that can be displaced in an application direction (12) relative to the container holder (3), the closing unit (2) having an electric motor (13) for applying a torque (M) about the application direction (12) to a through the closing unit (2) has received screw cap (11), and a control/regulation device (4) for controlling/regulating the electric motor (13), characterized in that the control/regulation device (4) is set up to close the electric motor (13) in such a way control/regulate that the screw cap (11) can be subjected to a plurality of successive torque pulses (P) of a predetermined level (Mp).

2. Device (1) according to claim 1, characterized in that the control device (4) is set up to act on the screw cap (11) with the plurality of successive torque pulses (P) when a predetermined condition of an unscrewing process of the screw cap is reached (11) to be provided on the container (8), and/or to be provided in response to a shutdown command for shutting down the device (1).

3. Device (1) according to claim 2, characterized in that the specified condition of the screwing-on process corresponds to reaching a specified angle of rotation of the electric motor (13) and/or the screw cap (11), and/or the specified condition of the screwing-on process corresponds to reaching a predetermined final torque (Mend), wherein preferably the first torque pulse (P) of the plurality of torque pulses (P) corresponds to reaching the final torque (Mend).

4. Device (1) according to one of the preceding claims, characterized in that the specified level (Mp) of at least the first torque pulse (P) corresponds to a specified final torque (Mend) of a screwing process, and/or that the number of torque pulses (P) can be adjusted, with the plurality of torque pulses (P) preferably being at least 2, 3, 4,

5,

6,

7 or 8 torque pulses (P). Device (1) according to one of the preceding claims, characterized in that a predetermined pulse duration (Tp) is provided between two successive torque pulses (P), the pulse duration (Tp) preferably being the same between all successive torque pulses (P), wherein the pulse duration (Tp) is preferably adjustable, the pulse duration (Tp) preferably being 10 ms to 0.1 s, particularly preferably 20 ms to 70 ms, particularly preferably 40 ms to 60 ms and very particularly preferably 50 ms. Device (1) according to one of the preceding claims, characterized in that each torque pulse (P) is followed by a torque drop (AM) of a predetermined level, with the torque drop (AM) preferably being 10 to 40%, particularly preferably 20 to 35% particularly preferably 25 to 30% of the predetermined height (Mp) of the torque pulses (P) corresponds, or the torque drop (AM) corresponds to a complete drop to zero. Device (1) according to one of the preceding claims, characterized in that the control/regulating device (4) is set up such that at least the torque pulses (P) following the first torque pulse (P) are applied suddenly and/or that the curve of the torque increase at least in the torque pulses (P) following the first torque pulse (P) before a torque pulse (P) increases exponentially or linearly or obeying another increasing function. Method for closing a container (8) with a screw cap (11), preferably for closing a beverage container with a screw cap (11) in a beverage bottling plant (5), comprising lowering a screw cap (11) onto a container to be closed

(8) in an application direction (12), and the application of a torque (M) to the application direction (12) on the screw cap (11), characterized in that that the screw cap (11) is subjected to a plurality of successive torque pulses (P) of a predetermined level (Mp).

9. The method according to claim 8, characterized in that the screw cap (11) is acted upon by the plurality of successive torque pulses (P) when a predetermined condition of a process of screwing the screw cap (11) onto the container (8) is reached, and/or in response to a shutdown command.

10. The method according to claim 9, characterized in that the predetermined condition of the screwing process corresponds to reaching a predetermined angle of rotation of an electric motor (13) and/or the screw cap (11), and/or the predetermined condition of the screwing process corresponds to reaching a predetermined final torque ( Mend) corresponds, wherein preferably the first torque pulse (P) of the plurality of torque pulses (P) corresponds to reaching the final torque (Mend).

11 . Method according to one of Claims 8 to 10, characterized in that the specified level (Mp) of at least the first torque pulse (P) corresponds to a specified end torque (Mend) of a screwing process, and/or that the number of torque pulses (P) is adjustable, wherein preferably the plurality of torque pulses (P) corresponds to at least 2, 3, 4, 5, 6, 7 or 8 torque pulses (P).

12. The method according to any one of claims 8 to 11, characterized in that a predetermined pulse duration (Tp) is provided between two consecutive torque pulses (P), the pulse duration (Tp) preferably being the same between all the respective consecutive torque pulses (P), the pulse duration (Tp) preferably being adjustable, the pulse duration (Tp) preferably being 10 ms to 0.1 s, particularly preferably 20 ms to 70 ms, particularly preferably 40 ms to 60 ms and very particularly preferably 50 ms.

13. The method according to any one of claims 8 to 12, characterized in that each torque pulse (P) is followed by a torque drop (AM) of a predetermined magnitude, with the torque drop (AM) preferably being 10% to 40%, particularly preferably 20% to 35% %, most preferably 25% to 30% of the predetermined height (Mp) of corresponds to torque pulses (P) or the torque decay (AM) corresponds to a complete drop to zero.

Device according to one of Claims 8 to 13, characterized in that at least the torque pulses (P) following the first torque pulse (P) are applied suddenly and/or that the progression of the torque increase at least in the torque pulses (P ) before a torque pulse (P) increases exponentially or linearly or obeying some other increasing function.