LOCKING DEVICE AND METHOD FOR LOCKING SCREW LOCKS

Description

[0001] The invention lies in the technical field of devices that automatically close screw caps of 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 force from the motor to the screw caps by means of the drive train.

[0002] It is known to close screw caps using a motor by appropriately translating the motor's power so that the cap is screwed onto a thread, for example, a thread on a container opening. A maximum motor torque is specified, for instance. This value can be readily measured with existing systems, and the motor can be controlled so that the maximum motor torque is not exceeded. Here, motor torque refers to the torque output by the motor. When transmitted to the cap, this motor torque is divided at least between the drive train's own torque and the torque acting on the screw cap. The tightness of a screw cap after closure can be quantified, for example, by the actual closure torque.The actual closing torque depends on the torque acting on the screw cap during the closing process. Furthermore, the properties of the screw cap and its counterpart, particularly the respective threads, also play a role in the closing process. To determine their influence on the actual closing torque, they can be quantified in the form of a counter-torque. For example, the coefficients of friction between the cap and its counterpart, the geometry of the threads, or the material elasticity can influence the magnitude of this counter-torque. The actual closing torque depends not only on the torque acting on the screw cap but also on this counter-torque.

[0003] Document DE 10 2006 025811 A1 describes a closing device for closing screw caps according to the preamble of claim 1.

[0004] Ideally, the actual locking torque should deviate as little as possible from a specified target locking torque. However, with known systems, a relatively wide variation in the actual locking torques results.

[0005] One of the problems underlying the invention is therefore to provide a closing device and a method for closing screw caps in which, on average, the deviation of the actual closing torque from the target closing torque is reduced.

[0006] The problem is solved by the subject matter of the independent claims. Preferred embodiments are described in the dependent claims.

[0007] The aforementioned locking device comprises, according to the invention, a control unit which is designed to dynamically adjust 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 locking torque, and an actual locking torque model.

[0008] Measuring the actual locking torque during operation is technically difficult. The inventors have also determined that a significant contribution to the deviations stems from the inertia and friction within the drive train, which can lead to a certain amount of overrun. Even if the actual locking torque were measured during operation and the motor were stopped upon reaching the target locking torque, the locking torque would still increase due to the drive train's overrun, with the amount depending on various system and / or operating parameters. Therefore, a simple offset correction does not always achieve the desired improvement.Furthermore, deviations in the properties of the closure and / or its counterpart, for example due to material factors, also play a role, since the temporal course of the counter-torque caused by them varies from closure process to closure process due to such deviations, especially the respective course towards the end of a closure process.

[0009] The claimed dynamic adjustment, however, enables a reliable reduction of the deviation of the actual locking torque from the target locking torque.

[0010] The target closing torque is a predetermined value that the actual closing torque should exhibit after the closing process is complete. The target closing torque can be stored in any location, for example, on a storage medium within the closing device and on a separate storage medium. It can also be set by a user. The specific value of the target closing torque, as well as its format and units, depends on the application and can be selected appropriately by a qualified professional.

[0011] In addition to the motor and drive train, the closing device can also include an element that interacts directly with the closure, such as a screw head, which is designed to hold the closure and / or to transmit force directly during the closing process. The motor can be, for example, an electric motor. The drive train can include, for example, gearboxes.

[0012] The screw closures can include closures, for example lids, for containers, wherein the closures have a thread, in particular an internal thread.

[0013] Dynamic adjustment, as used here, means that throughout the entire closing process, for example by means of a control process that receives the actual values ​​of the motor's operating parameters and adjusts them to the set values ​​in order to regulate to a predetermined target closing torque. The closing device can be designed in such a way that the measurement and adjustment of the motor operation, in particular the calculation of the actual closing torque using the actual closing torque model, are carried out continuously.

[0014] In particular, a continuous calculation of the drivetrain's intrinsic torque and the resulting derivation of the actual locking torque can be performed, 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 motor torque (torque output by the motor) and the drivetrain's intrinsic torque.

[0015] According to the invention, the actual locking torque model is designed such that, based on a modeled torque acting on the lock, it provides a modeled actual locking torque resulting from this modeled torque.

[0016] The torque acting on the closure can result from the motor torque, the drivetrain's own torque, and potentially other system parameters, such as friction, and is the torque transmitted to the closure. The closure torque depends on the torque acting on the closure as well as the counter-torque. The counter-torque can depend, for example, on the properties of the closure and / or its counterpart, particularly its threads, as explained above. These properties and parameters can therefore be incorporated into the modeled torque acting on the closure and the modeled closure torque.

[0017] The actual locking torque model can be designed to provide the torque acting on the locking mechanism using a drive train model, wherein the drive train model in particular includes a modeled intrinsic torque of the drive train.

[0018] The powertrain model can be designed to provide a value for the intrinsic torque of the powertrain based on inertia and / or friction in the powertrain.

[0019] The control device is designed according to the invention to dynamically adapt the motor operation based on a control loop.

[0020] According to the invention, the control loop is designed to output a value and / or a range of values ​​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 locking torque as input variables, for at least one operating parameter to be set.

[0021] According to the invention, the control loop is designed to determine a current value of the actual locking torque using the actual locking torque model, and to determine the value and / or the range of values ​​and / or the upper and / or lower limit for the value of the at least one operating parameter to be set based on a comparison of the current value of the actual locking torque with the value of the target locking torque.

[0022] The control loop can be designed to determine the value and / or the range of values ​​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 locking torque model, an approximation of the value of the actual locking torque to the target locking torque can be expected when the value of the operating parameter to be set is adjusted accordingly.

[0023] The control unit can be configured to set a value for an operating parameter on the motor 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.

[0024] The operating parameter to be set can include motor speed and / or motor torque.

[0025] The closing device can be designed to determine a counter-torque value, in particular the counter-torque described above, which is caused, for example, by the screw cap, using the actual closing torque model and the set value of the operating parameter, an expected actual value of the operating parameter and the measured value of the operating parameter.

[0026] The description also provides a capper not specifically claimed, comprising at least one of the capping devices described above. The capper can be designed for continuous operation. The capper, particularly the capper designed for continuous operation, can be in the form of a machine comprising a plurality of the capping devices described above. The machine can be in the form of a rotary unit and comprise a plurality of capping devices according to the invention. In this case, the capping devices can be arranged, in particular, on the outer circumference of a carousel of the rotary unit, which is designed to transport the containers to be capped. In particular, the capping devices can be arranged at regular intervals on the outer circumference of the carousel.

[0027] The use of multiple sealing devices is advantageous for increased throughput. Especially in systems with a large number of sealing devices, particularly in rotary machines, it is particularly beneficial to perform the sealing process in a motorized manner, as quickly as possible, yet with precision, due to this high throughput. Therefore, the use of the sealing device described above enables high throughput with high quality, especially in such machines.

[0028] The description also provides a filling plant, not specifically claimed, in particular for filling foodstuffs, which includes one or more of the above-described closing devices, in particular at least one of the above-described cappers, in particular at least one of the above-described rotary machines.

[0029] 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 closing torque, and an actual closing torque model.

[0030] The actual locking torque model is designed in such a way that, based on a modeled torque acting on the locking mechanism, it provides a modeled actual locking torque resulting from this modeled torque.

[0031] The process steps can be executed as a control procedure, meaning the steps can be repeated and the values ​​of the operating parameters can be dynamically adjusted. In particular, the measurement of the actual value of the operating parameter and the adjustment of the motor operation can be performed continuously.

[0032] According to the invention, the motor 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 locking torque as input variables, for at least one adjustable operating parameter of the motor.

[0033] According to the invention, the control loop is designed to determine a current value of the actual locking torque using the actual locking torque model, and to determine the value and / or the range of values ​​and / or the upper and / or lower limit for the value of the at least one operating parameter to be set based on a comparison of the current value of the actual locking torque with the target locking torque.

[0034] The control loop can be designed in particular to determine the value and / or the range of values ​​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 locking torque model, an approximation of the value of the actual locking torque to the target locking torque can be expected when the value of the operating parameter to be set is adjusted accordingly.

[0035] The procedure may include setting a value for the operating parameter on the motor by means of a control device, 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.

[0036] The features and advantages described in connection with the device are also applicable to the method by analogy.

[0037] Further features and advantages are explained below using the example figures. These show: Figure 1 a schematic, non-scale representation of a locking device according to one embodiment and Figure 2 a control loop according to one embodiment.

[0038] In Figure 1A schematic and not-to-scale drawing of a locking device 1 of an embodiment of the invention is shown. The locking device comprises a motor 2, a drive train 3, and a screw head 4.

[0039] Furthermore, the figure shows a holder 5, which may 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.

[0040] Furthermore, 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. The container has a thread 6a at the end to be closed, here an example of an external thread, which fits the thread of the screw cap. It is understood that the closing device is not limited to closing precisely this type of container and closure.

[0041] The figure also shows a sensor 8, which can be attached to the motor or integrated into the motor. The sensor is designed to measure actual values ​​of at least one operating parameter of the motor, for example, to detect the motor speed and / or the motor torque.

[0042] Furthermore, a control unit 9 is shown which is connected to the sensor via a data connection 10, wherein the sensor and the control unit are designed such that data acquired by the sensor are transmitted to the control unit. Alternatively, the control unit and the sensor can be integrally designed.

[0043] The control unit is designed to set the respective value of one or more operating parameters of the motor. For this purpose, the control unit can have a data connection 11 to the motor. Alternatively, the control unit can be integrated with the motor.

[0044] The following describes a method for closing screw caps, which can be carried out in particular with the closing device described above.

[0045] In particular, to close a screw cap, the screw cap can be screwed onto the threaded end of a container. For example, the container can be held by a holder and the screw cap by a screw head. The motor can be operated, for example, controlled by a control unit, and the motor power can be transmitted to the screw cap via a drive train, especially through the screw head. The transmission of the motor power can include a gear reduction and / or redirection of the motor power.

[0046] Motor operation is dynamically adjusted using a measured actual value of a motor operating parameter, such as actual speed, target locking torque, and an actual locking 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.

[0047] For example, based on the measured actual value of the operating parameter and a specified target locking 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 using the actual locking torque model for at least one operating parameter of the motor to be set.

[0048] For example, a set motor speed and / or a set motor torque and / or a maximum value for the motor torque, to which the motor torque is limited, i.e. an upper limit for the motor torque, can be determined and output.

[0049] The procedure may include determining a current actual locking torque using the actual locking torque model, and, based on the current actual locking torque and the target locking torque, determining the value and / or range of values ​​and / or the upper and / or lower limit for the at least one operating parameter to be set. This may involve, for example, comparing the actual locking torque with the target locking torque, and in particular, subtracting them.

[0050] The value and / or range of values ​​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 locking torque model, an approximation of the value of the actual locking torque to the target locking torque can be expected when the value of the operating parameter to be set is adjusted accordingly.

[0051] The motor then sets a value 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.

[0052] The process steps described above are executed as a control procedure, meaning that the steps are repeated and the values ​​of the operating parameter are dynamically adjusted. Measurement, determination, and output can be performed continuously.

[0053] An exemplary control loop 12, which can be used for the procedure described above and / or in the closing device described above for dynamically adjusting the motor operation, is shown in Figure 2The control loop includes, in particular, a locking torque controller 13. Here, the locking torque is controlled, with the input variables for the locking torque controller being the target locking torque and the actual locking torque.

[0054] In addition to the locking torque controller, the control loop includes a section 14 which, using a locking torque model, determines the actual locking torque from the motor's current speed and the (limited) motor torque and outputs it to the locking torque controller. This section also performs an example model of the drive train's intrinsic torque.

[0055] 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

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.