EP2203377B1 - Method and device for closing containers - Google Patents

Description

The present invention relates to a method and a device for closing containers according to the preamble of claims 1 and 9. From the prior art, such devices for sealing containers have long been known, see for example EP 1 249 426 A1 , In this case, a container for a beverage bottle is usually filled with the beverage and then sealed. In this closure, a screw cap is screwed onto the container. The plastic screw cap, which is screwed onto the containers, should meet several requirements. On the one hand, it must ensure tightness even at high internal pressures. Furthermore, he should also offer a visible guarantee band protection against manipulated opening and finally, the screw should be produced at a low price.

From the prior art, various screw caps with the mentioned warranty bands are known. These guarantee bands are pushed onto the container when screwed over a ring provided at the mouth of the container. If you open the closure, it inevitably leads to a tear of the guarantee strip so that it can be easily determined that the container has already been opened once. To meet the increasing demands in terms of product warranty, these guarantee bands of screw caps are always improved and are always close to the mouth of the bottle.

By this close concern, however, a very high Aufschraubmoment necessary to push the first time screwing the closure on the container, the guarantee strip on the corresponding ring. This means that from the prior art known devices for closing the containers and also with servo closer (?) A higher end torque is required so that the closure goes into the seal or so that the guarantee strip snaps into place at the mouth. However, this high end torque during the rotation is uncomfortable to handle, because the opening of the bottle is considerably more difficult.

It is therefore the object of the present invention to provide an apparatus and a method which make it possible to achieve a desired low end torque of the screw-on closure even when using tight-fitting guarantee bands. This is inventively achieved by the method of claim 1 and an apparatus according to claim 9. Advantageous embodiments and further developments are the subject of the dependent claims.

In a method according to the invention for closing containers with closures by means of a closing device, the closures are screwed or screwed onto openings of the containers for closing. An end torque is set for closing the containers, with which the closing operation is completed and this final torque is less than a maximum torque which is applied at least once during the entire closing process.

The final torque is thus understood to mean that torque at which the closing process is stopped or is ended. This is at the same time the final torque with which the bottle is closed. This final torque should, as mentioned above, on the one hand be high enough to ensure a tightness of the bottle, on the other hand, it should also be possible for the user to open the container closure without excessive force.

A maximum torque is achieved throughout the closing process, which is higher than the said final torque. This maximum torque occurs in particular in the temporal section in which just the guarantee band is pushed over the corresponding ring over the mouth of the container. While in the prior art, the final torque is at least equal to the maximum torque, but in particular higher than this, a reduction of the end torque is achieved by the inventive method. This overall high torque in the range of the guarantee strip is possible while still a desired low end torque of the screwed closure.

Preferably, the container is held and the torque applied to the closure of the container.

In a preferred method, a torque which is at least equal to the maximum torque is made possible for at least a period of the closing process. Preferably, in the said period of the closing operation, the closing device is not subject to any restrictions, so that the maximum torque is limited only by physical conditions of the closing device. In other words, will in the said period of the closing operation, the torque of the closing device is not limited. However, it would also be possible to define, in addition to the final torque, a maximum torque that is below the torque defined by physical conditions of the closure device, such as the maximum torque of the engine.

At least one characteristic of a torque of the closing device size is measured. This size is particularly preferably measured continuously during the closing process. Advantageously, the characteristic quantity is a current, i. H. the current with which a motor which drives the closing device is measured is measured. This current is at the same time a measure of the torque to be applied or applied. However, other sizes could be measured, for example, directly the transmitted forces or torques.

Changes in the characteristic size are determined during the sealing process. More specifically, it is determined whether the characteristic quantity and thus the applied torque increases, stays the same or decreases depending on the time or angle of rotation.

According to the invention, with a decrease in the torque during the closing, the maximum torque of the closing device is also set the predetermined end torque. As stated above, the maximum torque is achieved during the closing process at the moment when the guarantee band is passed over the ring at the mouth of the Container slides. Then the torque decreases. Thus, the decrease of the torque is an indication that now the guarantee band has been pushed over the ring on the container. Thus, at this moment, the torque of the closing device can be set to the final torque to ensure in this way that the container is closed only with the final torque.

Preferably, therefore, the closing operation is divided into at least two sections, wherein in these sections different torques are permitted for rotating the closure body. In contrast, only a maximum torque is set in the prior art and this depends on the maximum torque which is necessary for placing the guarantee strip.

In a further advantageous method, a predetermined limit value for the characteristic quantity (D) is determined, and upon reaching this limit value, the shutter is rotated further by a predetermined angle of rotation or for a predetermined period of time starting from the rotational position at which this limit value occurs. While it is determined in the above variants by means of torque measurements or current measurements that a maximum torque has already been reached and thus the guarantee band has already been pushed over the ring, in this variant, the torque is determined in particular before the maximum torque is reached.

Starting from the limit value, the closure is then further screwed by a predetermined angle of rotation, this angle of rotation being sufficient for the guarantee strip to push over the ring. In this range, preferably, the torque is preferably not limited, so that the maximum torque range can be overcome.

Preferably, after the closure is rotated by the predetermined angle, the final torque is set, i. after overcoming the area that requires the maximum torque.

In a further predetermined method, the predetermined limit value is in time before reaching the maximum torque. This means that the predetermined limit is reached in the rising edge of the torque curve.

The present invention is further directed to a device for closing containers. This device has a holding device which holds the containers. Furthermore, a closure device is provided, which rotates container closures relative to the containers and preferably rotates onto the containers in order to close them. A control device is provided, which controls a torque with which the closures are rotated relative to the container, and furthermore a measuring device is provided, which determines a value characteristic of this torque, wherein the control device is designed such that it gives the closure a final torque , which is less than a maximum torque of the closing device. More specifically, the control means preferably provides the closing means with an end torque which is less than the maximum during the closing process reached torque. The measuring device is preferably a current measuring device. This can be integrated directly into the control structure of a drive motor for the device.

Furthermore, the control device determines a time characteristic of the characteristic value during the closing process. If this characteristic value, i. the current, and thus the torque decreases, a maximum torque (or end torque) is set according to the invention for the further course, which is below this determined value of the torque.

In a further preferred embodiment, the device has a rotational position sensor which determines a rotational position of the closure. With the help of this rotational position sensor, a certain rotational position can be approached, after which a certain limit of the torque has been detected. Thus, the device preferably also has a control device, which causes that upon reaching a certain limit value of the torque, the closure is further rotated by a predetermined angle.

• Darin zeigen:
  • Fig. 1 eine Detaildarstellung einer erfindungsgemäßen Vorrichtung zum Verschließen von Behältnissen.
  • Fig. 2 einen Verlauf des Drehmoments nach dem Stand der Technik.
  • Fig. 3 einen Verlauf des Drehmoments bei einem erfindungsgemäßen Verfahren; und
  • Fig. 4 einen Verlauf des Drehmoments bei einem weiteren erfindungsgemäßen Verfahren.

Further advantages and embodiments will be apparent from the attached drawings:

• Show:
  • Fig. 1 a detailed representation of a device for closing containers according to the invention.
  • Fig. 2 a curve of the torque according to the prior art.
  • Fig. 3 a curve of the torque in a method according to the invention; and
  • Fig. 4 a curve of the torque in a further inventive method.

Fig. 1 shows a detailed view of a device for closing containers. In this case, the reference numeral 10 refers to a container which has an opening 10a, on which a closure 14 can be screwed. For this purpose, a closing device 1 is provided, which initially moves the container closure to the mouth 10a and then rotates the closure 14 with respect to the mouth. The container below the mouth is held more accurately below a support ring of a holding device 12. The reference numeral 6 refers to a motor which causes the rotational movement of the closure relative to the container. This motor 6 has a measuring device (not shown), which measures the current with which the motor is acted upon. Furthermore, the motor also has a control device 16 which controls the applied torque. The reference numeral 18 refers to a rotational position sensor, which determines a rotational position of the closure, in particular with respect to the container 10.

Fig. 2 shows a curve of the torque D in a method according to the prior art. The closure is screwed onto the thread 10a. Once the guarantee strip on the ring of the estuary, which is also called Pilverprof ring is called starts, is a correspondingly high torque D _max which represents a local maximum and thus for the motor requires an increased current (area A). This increased torque D _max is represented by the lower dashed horizontal line. As soon as the guarantee strip has been overcome or arranged in its target area, the torque drops again, as illustrated by area B. In the further course, ie as soon as the closure is screwed substantially completely on the mouth, the torque of the closing device will rise again to a value which is also higher than the maximum torque D _max for pushing the guarantee strip. Thus, the end torque must be higher here than the screw-on torque of the guarantee strip. If the final torque D _{end were} lower, the shutter would stop at the rise of the belt and would not seal the container 10 tightly.

Fig. 3 shows a curve of a torque for a method according to the invention. The final torque D _{End is} lower than the maximum torque D _max .

Here, the closing process is divided into two sections. First, in a first section I comprising the sections A and B, the maximum torque of the drive device is released. If it now requires the maximum torque D _max to overcome the guarantee strip, then falls off the required torque. This also reduces the current consumption of the servomotor. As soon as the power consumption decreases, this is measured, more precisely, a predetermined size of the waste is measured. Thus, a second section II is defined and in this second section II, the maximum end torque D _{End is} set. More specifically the drive motor for the closing only the required power for this final torque D _End provided. This makes it possible to achieve a final torque which is lower than the maximum torque D _max .

The current is preferably measured over the entire range A and B, and the second portion is only initiated when the torque D drops over a slightly larger portion ΔT. In this way, even small torque fluctuations can be taken into account so that the final torque is not accidentally set at the wrong time and in particular too early. It should be noted that it can also locally in the area A for a short time to torque decreases. If one does it in this area to set the final torque D _end, the bottle could not be reliably closed.

Thus, it is possible, for example, to measure the torque in fixed temporal intervals and only, if also results from such a measurement, an actual reduction of the torque to set the torque D _End . By way of illustration, in region A, a subregion Z is shown in which the torque decreases locally. If one were to take this area as the basis for the machine control, the torque D _end would be inadvertently set in this area. Therefore, it is preferable to measure the torque over a larger time range t in order to be able to filter out such measurement fluctuations as in the region Z. The time t is plotted on the ordinate, but it would also be possible on the ordinate to apply a machine or rotation angle for the closure.

The reference M refers to an adjustable minimum torque drop. As soon as the torque falls below the value represented by the line M again starting from the maximum torque D _max , the final torque D _End can be set. Also in this way it is possible to avoid an accidental specification of the final torque D _End due to slight fluctuations in the torque D. The reference M _ges denotes the total torque drop.

The torque _Dend is the torque needed to close the container tightly.

Fig. 4 shows a further inventive method. In this method, a higher current is given at the beginning of the closing process, as is necessary to overcome the increased intermediate torque or the maximum torque D _max . In this case, the maximum current consumption of the motor can be allowed.

Now, when the current consumption rises during the closing process, a predetermined current value is defined as a _switching changeover point D. Starting from this current value or the rotation angle of the shutter 14 corresponding to this current quantity, the shutter is further rotated by a predetermined head rotation angle ω (for example by 100 °.) This rotation angle is further rotated (for example by 100 °.) This rotation angle is selected such that the motor increases or even maximum current consumption overcomes the maximum torque D _max .

Once the motor has reached the resulting critical angle, which can be determined, for example via rotary position sensor, the final torque D _{End is} specified. Also in this way it is possible to overcome a strict lock guarantee band to allow the engine high power consumption and thus a high torque. Once the warranty strip has been overcome, the motor current draw is limited to the desired closing end torque.

Preferably, the above-mentioned head rotation angle ω is set so that the rotational position of the shutter is in the range of a minimum of the torque. This head rotation angle ω can be determined beforehand on the basis of empirical data. To determine this head rotation angle ω, a plurality of the in Fig. 4 evaluated courses are evaluated. Furthermore, the device according to the invention can have a storage device in which different head rotation angles ω are stored depending on different types of bottles.

In any case, the head rotation angle ω should be sufficient to allow the closure of a region A of the in Fig. 4 Course shown in a range B to rotate.

In the Fig. 4 The procedure shown is particularly suitable in cases where a high intermediate torque or maximum torque D _max occurs. Furthermore, this method is particularly suitable when the torque drop M is very small or too different due to closure inaccuracies.

Instead of specifying a certain angle of rotation ω, it would also be possible, starting from the D _switching nor the rotation for continue for a certain period of time and then set the limit to the final torque D _End defined. This period of time corresponds to a certain angle of rotation which is sufficient to overcome the maximum torque D _max defined. In this case, the apparatus preferably has a timer which allows rotation for the above-mentioned period of time.

Claims (11)

1. Method for closing containers (10) with closures (14) by means of a closing device (1), wherein the closures (14) are rotated onto mouths (10a) of the containers (10) for closing purposes, and for closing the containers (10), a final torque (D_final) is predefined, with which the closing operation is completed, and this final torque (D_final) is lower than a maximum torque (D_max) which is applied at least once during the entire closing operation and wherein at least one variable characteristic of a torque (D) of the closing device is measured, wherein changes of the characteristic variable during the closing operation are determined,
   characterised in that
   with a decrease of the torque during the closing operation the maximal torque of the closing device (1) is set to the final torque (D_final).
2. Method according to claim 1, characterised in that, for at least one period of time during the closing operation, a torque is possible which is at least equal to the maximum torque (D_max).
3. Method according to claim 1, characterised in that, for at least one period of time during the closing operation, a torque (D) of the closing device (1) remains unlimited.
4. Method according to claim 1, characterised in that the characteristic variable is a current (I) with which the closing device (1) is operated.
5. Method according to at least one of the preceding claims, characterised in that the closing operation is divided into at least two sections (I, II), wherein different torques for rotating the closing bodies are permitted in these sections (I, II).
6. Method according to at least one of the preceding claims, characterised in that a predetermined limit value (D_changeover) for the characteristic variable (D) is determined and, when this limit value is reached, the closure is rotated further by a predefined rotation angle (ω) or for a predefined duration.
7. Method according to claim 6, characterised in that the final torque (D_final) is set after rotating the closure (14).
8. Method according to claim 6, characterised in that the predetermined limit value (D_changeover) is determined temporally before the maximum torque (D_max) is reached.
9. Device for closing containers (10), comprising a holding device (12) which holds the containers (10) and a closing device (1) which rotates container closures relative to the containers (10) in order to close the latter, wherein a control device (16) is provided which controls a torque with which the closures are rotated relative to the containers (10), and wherein a measuring device is provided which determines a value characteristic of this torque, wherein the control device (16) is configured in such a way that it defines for the closing device (1) a final torque (D_final) which is lower than a maximum torque (D_max) of the closing device (1), which is reached at least once during the closing operation,
   characterised in that
   the control device (16) determines a course of time of the characteristic value during the closing operation and wherein the control device (16) sets the maximal torque of the closing device (1) to the final torque (D_final) in case of a decrease of the torque during the closing operation.
10. Device according to claim 9, characterised in that the measuring device is a current measuring device.
11. Device according to at least one of the preceding claims 9 - 10, characterised in that the device comprises a rotary position sensor (18) which determines a rotary position of the closure (14).

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