EP3795530B1 - Closure device and method for closing screw caps - Google Patents

Description

The invention is in the technical field of devices that automatically close screw caps on containers, for example motor-driven. It relates in particular to a closing device for closing screw caps comprising a motor and a drive train and designed to transmit power from the motor to the screw caps by means of the drive train.

It is known to close screw caps using a motor by appropriately translating the motor force so that the screw cap is turned onto a thread, for example a thread on a container opening. For example, a maximum motor torque is specified. This value can be easily recorded using existing systems and the motor can be controlled so that the maximum motor torque is not exceeded. The motor torque here refers to the torque output by the motor. When transferred to the cap, this motor torque is divided at least into the inherent torque of the drive train and the torque acting on the screw cap. How tightly a screw cap is closed after closing can be quantified, for example, by the actual closing torque. The actual closing torque depends on the torque acting on the screw cap during the closing process. In addition, the properties of the screw cap and the counterpart, in particular the respective thread, also play a role when closing. In order to determine their influence on the actual closing torque, these can be quantified in the form of a counter torque. For example, the friction coefficients of the closure and counterpart, the geometry of the thread or the elasticity of the material can influence the magnitude of the counter torque. The actual closure torque depends not only on the torque acting on the screw cap but also on this counter torque.

document DE 10 2006 025811 A1 describes a closing device for closing screw caps according to the preamble of claim 1.

In principle, it is desirable that the actual closing torque deviates as little as possible from a specified target closing torque. However, the known systems result in a relatively wide spread of the actual closing torques.

One object underlying the invention is therefore to provide a closing device and a method for closing screw caps, in which the deviation of the actual closing torque from the target closing torque is reduced on average.

The object is solved by the subject matter of the independent claims. Preferred embodiments are described in the dependent claims.

According to the invention, the closing device mentioned at the outset comprises a control device which is designed to dynamically adapt the motor operation using a measured actual value of an operating parameter of the motor, for example an actual speed of the motor, a target closing torque, and an actual closing torque model.

Measuring the actual closure torque during operation is technically difficult. The inventors have also determined that a significant contribution to the deviations is made by the inertia and friction that occur in the drive train, which can lead to a certain amount of lag, among other things. Even if the actual closure torque were measured during operation and the motor were stopped when the target closure torque was reached, the drive train's lag would still increase the closure torque by an amount that depends on various system parameters and/or operating parameters. A correction with a simple offset does not lead to the desired improvement in all cases. In addition, deviations in the properties of the closure and/or the closure's counterpart, for example due to the material, also play a role, since the temporal progression of the counter torque caused by them varies from closure process to closure process due to such deviations, in particular the respective progression towards the end of a closure process.

The claimed dynamic adjustment, however, enables a reliable reduction of the deviation of the actual closing torque from the target closing torque.

The target closure torque is understood to be a predetermined value that the actual closure torque should have after completion of the closure process. The target closure torque can be stored anywhere, for example on a storage medium of the closure device and a separate storage medium. It can have been stored by a user. How high the target closure torque is and in what form or units it is specified depends on the actual application and can be selected appropriately by the specialist.

In addition to the motor and the drive train, the closure device may further comprise an element that interacts directly with the closure, for example a screw head, which for holding the closure and/or the direct transmission of power during the closing process. The motor can be an electric motor, for example. The drive train can include a gear, for example.

The screw caps may comprise closures, for example lids, for containers, wherein the closures have a thread, in particular an internal thread.

Dynamic adaptation is understood here to mean that during the entire closing process, for example by means of a control process that receives the actual values of the operating parameters of the motor and adjusts the set values of the operating parameters of the motor in order to regulate to a predetermined target closing torque. The closing device can in particular be designed in such a way that measurement and adaptation of the motor operation, in particular a calculation of the actual closing torque using the actual closing torque model, take place continuously.

In particular, a continuous calculation of the drive train's own torque and the actual locking torque derived from this can be carried out and the values of the operating parameters can be adjusted based on this calculation. In the simplest case, the actual locking torque model can generate a value for the actual locking torque by calculating the difference between the engine torque (torque output by the engine) and the drive train's own torque.

According to the invention, the actual closure torque model is designed such that, based on a modeled torque acting on the closure, it provides a modeled actual closure torque resulting from this modeled torque.

The torque acting on the shutter can result from the motor torque, the inherent torque of the drive train and possibly other system parameters, such as friction, and is the torque that is transferred to the shutter. The shutter torque depends on the torque acting on the shutter and the counter torque. The counter torque can, for example, depend on the properties of the shutter and/or its counterpart, in particular their thread, as explained above. These properties and parameters can therefore be incorporated into the modeled torque acting on the shutter and the modeled shutter torque.

The actual shutter torque model may be designed to provide the torque acting on the shutter using a drive train model, wherein the Drivetrain model in particular includes a modeled inherent torque of the drivetrain.

The drivetrain model may be configured to provide a value of the drivetrain's inherent torque based on inertia and/or friction in the drivetrain.

According to the invention, the control device is designed to dynamically adapt the engine operation based on a control loop.

According to the invention, the control loop is designed to output a value and/or a value range and/or an upper and/or lower limit for the value based on the measured actual value of the operating parameter and a predetermined target closure torque as input variables for at least one operating parameter to be set.

According to the invention, the control loop is designed to determine a current value of the actual closure torque using the actual closure torque model and, based on a comparison of the current value of the actual closure torque with the value of the target closure torque, to determine the value and/or the value range and/or the upper and/or lower limit for the value of the at least one operating parameter to be set.

The control loop can be designed to determine the value and/or the value range and/or the upper and/or lower limit for the value of the operating parameter to be set such that, according to the actual closure torque model, an approximation of the value of the actual closure torque to the target closure torque is to be expected when the value of the operating parameter to be set is set accordingly.

The control device can be designed to set a value for an operating parameter on the engine which corresponds to the output value and/or is within the output value range and/or is below the output upper limit and/or is above the output lower limit.

The operating parameter to be set may include an engine speed and/or an engine torque.

The closing device can be designed to determine a value of a counter torque, in particular the counter torque described above, which is caused for example by the screw cap, by means of the actual closure torque model using a or the set value of the operating parameter, an expected actual value of the operating parameter and the measured value of the operating parameter.

The description also provides a closer, not specifically claimed, comprising at least one of the closing devices described above. The closer can in particular be designed for continuous operation. The closer, in particular the closer designed for continuous operation, can be designed in the form of a machine comprising a plurality of the closing devices described above. The machine can in particular be designed in the form of a rotary machine and comprise a plurality of closing devices according to the invention. In this case, the closing devices can in particular be arranged on the outer circumference of a carousel of the rotary machine, which is designed to transport the containers to be closed. In particular, the closing devices can be arranged at equal intervals on the outer circumference of the carousel.

The provision of several closing devices is advantageous for increased throughput. Especially in arrangements with a large number of closing devices, especially in rotary machines, it is particularly advantageous due to this high throughput to carry out the closing in a motorized manner, as quickly as possible but still precisely, so that the use of the closing device described above enables a high throughput with high quality, especially in such machines.

The description also provides a filling system, in particular for filling foodstuffs, which is not specifically claimed and which comprises one or more of the closing devices described above, in particular at least one of the closing machines described above, in particular at least one of the rotary machines described above.

The invention also relates to methods for closing screw caps, wherein force is transmitted from a motor to the screw caps by means of a drive train for closing. The motor operation is dynamically adjusted using a measured actual value of an operating parameter of the motor, for example an actual speed, a target closure torque, and an actual closure torque model.

The actual closure torque model is designed such that, based on a modeled torque acting on the closure, it provides a modeled actual closure torque resulting from this modeled torque.

The process steps can be carried out as control processes, i.e. the steps can be carried out repeatedly and the values of the operating parameters can be adjusted dynamically. The measurement of the actual value of the operating parameter and adjustment of the engine operation can in particular be carried out continuously.

According to the invention, the engine operation is dynamically adapted based on a control loop. The control loop is designed to output a value and/or a value range and/or an upper and/or lower limit for the value based on the measured actual value of the operating parameter and a predetermined target closing torque as input variables for at least one operating parameter of the engine to be set.

According to the invention, the control loop is designed to determine a current value of the actual closure torque using the actual closure torque model and, based on a comparison of the current value of the actual closure torque with the target closure torque, to determine the value and/or the value range and/or the upper and/or lower limit for the value of the at least one operating parameter to be set.

The control loop can in particular be designed to determine the value and/or the value range and/or the upper and/or lower limit for the value of the operating parameter to be set in such a way that, according to the actual closure torque model, an approximation of the value of the actual closure torque to the target closure torque is to be expected when the value of the operating parameter to be set is set accordingly.

The method may comprise setting a value for the operating parameter by means of a control device on the engine, which value corresponds to the output value and/or is within the output value range and/or is below the output upper limit and/or is above the output lower limit.

The features and advantages described in connection with the device are also applicable analogously to the method.

• Figur 1 eine schematische, nicht-maßstabsgetreue Darstellung einer Verschließvorrichtung gemäß einer Ausführungsform und
• Figur 2 einen Regelkreis gemäß einer Ausführungsform.

Further features and advantages are explained below using the example figures. They show:

• Figure 1 a schematic, non-scale representation of a closing device according to an embodiment and
• Figure 2 a control loop according to an embodiment.

In Figure 1 A closure device 1 of an embodiment of the invention is shown schematically and not to scale. The closure device comprises a motor 2, a drive train 3 and a screw head 4.

Furthermore, the figure shows a holder 5, which can be part of the closing device, but does not have to be, and is designed to hold a container 6, in particular to hold the container in the working area of the screw head.

In addition, a screw cap 7 held by the screw head is shown. The screw cap has a thread 7a, here an internal thread. To illustrate the thread, a cross-section through the screw cap is shown here. The container has a thread 6a on the end to be closed, here an external thread for example, which matches the thread of the screw cap. It is understood that the closing device is not limited to closing exactly this type of container and closure.

The figure also shows a sensor 8, which can be attached to the engine or formed integrally with the engine. The sensor is designed to measure actual values of at least one operating parameter of the engine, for example to detect the engine speed and/or the engine torque.

Furthermore, a control device 9 is shown, which is connected to the sensor via a data connection 10, wherein the sensor and the control device are designed such that data detected by the sensor are transmitted to the control device. Alternatively, the control device and the sensor can be designed integrally.

The control device is designed to set the respective value of one or more operating parameters of the engine. For this purpose, the control device can have a data connection 11 to the engine. Alternatively, the control device can be designed integrally with the engine.

The following describes a method for closing screw caps, which can be carried out in particular with the closing device described above.

In particular, to close a screw cap, the screw cap can be screwed onto the thread of a container. For example, the container can be held by a holder and the screw cap by a screw head. The The motor can be operated, for example controlled by a control device, and the motor power can be transmitted to the screw cap by a drive train, in particular via the screw head. The transmission of the motor power can include a transmission and/or redirection of the motor power.

The engine operation is dynamically adjusted using a measured actual value of an operating parameter of the engine, for example an actual speed, a target closure torque, and an actual closure torque model. A control loop can be used for this purpose, for example the one described below in connection with Figure 2 control loop described in detail.

For example, based on the measured actual value of the operating parameter and a specified target closing torque as input variables, a value and/or a value range and/or an upper and/or lower limit for the value can be determined and output by means of the actual closing torque model for at least one operating parameter of the engine to be set.

For example, an engine speed to be set and/or an engine torque to be set and/or a maximum value for the engine torque to which the engine torque is limited, i.e. an upper limit for the engine torque, can be determined and output.

The method can include determining a current actual closure torque using the actual closure torque model, and determining the value and/or the value range and/or the upper and/or lower limit for the at least one operating parameter to be set based on the current actual closure torque and the target closure torque. For this purpose, for example, the actual closure torque can be compared with the target closure torque, in particular subtracted.

The value and/or value range and/or the upper and/or lower limit for the value of the operating parameter to be set can be determined in such a way that, according to the actual closure torque model, an approximation of the value of the actual closure torque to the target closure torque is to be expected when the value of the operating parameter to be set is set accordingly.

A value is then set on the engine for the operating parameter that corresponds to the output value and/or is within the output value range and/or is below the output upper limit and/or is above the output lower limit.

The process steps described above are carried out as control processes, i.e. the steps are carried out repeatedly and the values of the operating parameters are dynamically adjusted. The measurement, determination and output can in particular be carried out continuously.

An exemplary control circuit 12 which can be used for the method described above and/or in the closing device described above for dynamically adjusting the engine operation is shown in Figure 2 shown. The control loop comprises in particular a closure torque controller 13. Here, the closure torque is controlled, the input variables for the closure torque controller being the target closure torque and the actual closure torque.

In addition to the closing torque controller, the control loop includes a section 14 that uses an actual closing torque model to determine the actual closing torque from the actual speed of the engine and the (limited) engine torque and outputs it to the closing torque controller. The section also carries out a modeling of the inherent torque of the drive train as an example.

It is understood that in general the features mentioned in the previously described embodiments are not limited to these specific combinations and are also possible in any other combinations.

Claims (10)

1. A closing device (1) for closing screw caps (7) comprising a motor (2) and a drive train (3) and configured to transmit force from the motor (2) to the screw caps (7) by means of the drive train (3),

   further comprising a control device (9) which dynamically adjusts the motor operation using a measured actual value of an operating parameter of the motor (2), a target closing torque and an actual closing torque model,

   wherein the actual closing torque model is configured in such a way that it provides a modelled actual closure torque resulting from this modelled torque based on a modelled torque acting on the closure,

   wherein the control device (9) is configured to dynamically adjust the motor operation based on a control loop (12),

   characterised in that the control loop (12) is configured to represent a value and/or a value range and/or an upper and/or lower limit for the value based on the measured actual value of the operating parameter and a predetermined target closing torque as input variables at least for one operating parameter to be set,

   wherein the control loop (12) is configured to determine a current value of the actual closing torque using the actual closing torque model and to determine the value and/or the value range and/or the upper and/or lower limit for the at least one operating parameter to be set based on a comparison of the current value of the actual closing torque with the value of the target closing torque.
2. The closing device (1) according to claim 1, wherein the actual closing torque model provides the torque acting on the cap using a drivetrain model, wherein the drivetrain model comprises in particular a modelled intrinsic torque of the drivetrain (3).
3. The closing device (1) according to claim 2, wherein the drive train model provides a value for the intrinsic torque of the drive train (3) as a function of mass inertia and/or friction in the drive train (3).
4. The closing device (1) according to claim 1 to 3, wherein the control loop (12) is configured to determine the value and/or the value range and/or the upper and/or lower limit for the operating parameter to be set in such a way that, according to the actual closing torque model, an approximation of the value of the actual closing torque to the value of the target closing torque is to be expected when the value of the operating parameter to be set is set accordingly.
5. The closing device (1) according to claim 1 or 4, wherein the control device (9) is configured to set a value on the motor (2) which corresponds to the output value and/or is in the output value range and/or is below the output upper limit and/or is above the output lower limit.
6. The closing device (1) according to any of claims 1, 4 or 5, wherein the operating parameter to be set comprises a motor speed and/or a motor torque.
7. The closing device (1) according to any of the preceding claims, wherein the device is configured to determine a counter-torque caused by the screw cap (7) by means of the actual closing torque model using a or the set value of the operating parameter, an expected actual value of the operating parameter and the measured value of the operating parameter.
8. A method for closing screw caps (7), wherein force is transmitted from a motor (2) to the screw caps (7) by means of a drive train (3) for closing,

   wherein the motor operation is dynamically adapted using a measured actual value of an operating parameter of the motor (2), a target closing torque and an actual closing torque model;

   wherein the actual closing torque model is configured in such a way that it provides a modelled actual closure torque resulting from this modelled torque based on a modelled torque acting on the closure,

   wherein the motor operation is dynamically adapted based on a control loop (12),

   characterised in that the control circuit (12) is configured to output a value and/or a value range and/or an upper and/or lower limit for the value based on the measured actual value of the operating parameter and a predetermined target closing torque as input variables at least for one operating parameter of the motor (2) to be set,

   wherein the control loop (12) is configured to determine a current value of the actual closing torque using the actual closing torque model and to determine the value and/or the value range and/or the upper and/or lower limit for the at least one operating parameter to be set based on a comparison of the current value of the actual closing torque with the target closing torque.
9. The method according to claim 8, wherein the control loop (12) is configured to determine the value and/or the value range and/or the upper and/or lower limit for the operating parameter to be set in such a way that, according to the actual closing torque model, an approximation of the value of the actual closing torque to the target closing torque is to be expected when the value of the operating parameter to be set is set accordingly.
10. The method according to claim 9, wherein by means of a control device (9) on the motor (2) a value is set which corresponds to the output value and/or lies within the output value range and/or lies below the output upper limit and/or lies above the output lower limit.

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