DEVICE FOR MEASURING A FORCE ON A LIFT SYSTEM, METHOD FOR CHECKING THE BALANCE OF A LIFT SYSTEM, AND A LIFT SYSTEM FOR EXECUTING THE METHOD

Description

[0001] The present invention relates to a device for an elevator system, a method for checking the balancing of an elevator system, and an elevator system.

[0002] An elevator system has vertically moving components, such as a cabin and at least one counterweight. These moving components are connected by at least one load-bearing element. The load-bearing element runs over at least one traction sheave of the elevator's drive unit. On one side of the traction sheave, the load-bearing element carries the constant weight of the counterweight. On the other side, it carries the variable weight of the cabin and any load being transported within. The drive unit applies a torque to compensate for the difference in these weight forces. This torque is transmitted to the load-bearing element through friction, or traction, between the load-bearing element and the traction sheave.

[0003] Before commissioning and / or during maintenance work, the functionality of the elevator system must be checked. In particular, the balance of the elevator system, i.e., the weight ratio between the cabin and the counterweight(s), may need to be checked.

[0004] WO2008071301A1 describes a method and a device for testing elevator systems.

[0005] WO2013068648A1 describes a method and a device for measuring the balance of an elevator and a method for balancing the elevator.

[0006] WO2021084012A1 reveals a cabin brake of an elevator system.

[0007] DE4311011A1 describes a method and a device for testing a lift.

[0008] There may be a need for an improved device and a simplified procedure for checking the balance of an elevator system. Furthermore, there may be a need for an elevator system in which a simplified procedure for checking the balance of the elevator system can be carried out.

[0009] Such a need can be met by a device, a method for checking the balancing of an elevator system, and an elevator system according to the main claims. Advantageous embodiments are defined in the dependent claims and described in the description.

[0010] The approach presented here simplifies the balancing check and eliminates the need for additional weight, which was conventionally used, for example, with lead blocks to alter the tensile force between the traction sheave and the cabin. Instead of the familiar additional weight in the cabin, one of the moving components is temporarily fixed, for example, to a rail system of the elevator, and the tensile force in the suspension system is changed. Unlike with additional weight, the tensile force can also be reduced. The force resulting from the changed tensile force is then measured at the fixed component.

[0011] Using the measured force, conclusions can be drawn about the weight of the counterweight and / or cabin, and thus about the balancing of the elevator system.

[0012] By measuring the force on the fixed component, the need to provide and return the additional weight, as well as to load and unload the cabin with the additional weight, can be eliminated. Measuring the force requires only at least one easily transportable device, such as the one presented here, with a locking mechanism and a measuring device.

[0013] According to a first aspect of the invention, a device for an elevator system according to claim 1 is presented.

[0014] According to a second aspect of the invention, a method for verifying the balancing of an elevator system according to claim 6 is presented, wherein the elevator system comprises at least one elevator control, a guide rail, at least one counterweight, and a cabin, wherein the at least one counterweight is connected to the cabin via at least one support means, comprising the steps: Connecting at least one device according to one aspect of the invention to the at least one guide rail; placing the at least one counterweight and / or the cabin onto the at least one device; changing a tensile force transmitted via support means to the at least one counterweight and / or the cabin; detecting a force value based on a force derived via the device into the rail system.

[0015] According to a third aspect of the invention, an elevator system is presented comprising at least one, preferably two, counterweight(s), a cabin and an elevator control system, wherein the elevator control system is configured for connection with a device according to a first aspect of the invention and for carrying out a method according to a second aspect of the invention.

[0016] A locking device can substantially prevent movement of at least one counterweight and / or the cabin along the guide rail in at least one direction. This direction can be, in particular, vertical. The locking device can constitute an insurmountable obstacle for the moving component (at least one counterweight and / or the cabin) in this direction. The locking device can transfer compressive and / or tensile forces exerted by the moving component into the rail system.

[0017] The locking device can have at least one hook for engaging in a corresponding recess in the rail system. The hook can be inserted into the recess and moved along it until a contact surface of the hook rests against an edge of the recess. The force can then be transferred into the rail system via the hook. The hook allows for tool-free assembly and disassembly of the device. The rail system can have several suitable recesses, allowing the device to be engaged at different positions within the rail system. The locking device can, in particular, have several identical hooks. Multiple hooks provide redundancy and increase the operational reliability of the device. They also allow a greater force to be transferred into the rail system.

[0018] At least one hook can be symmetrical. This allows the hook to be inserted into the recess in opposite orientations. Alternatively or additionally, the symmetrical hook can transfer tensile forces of the load-bearing element upwards and the weight of the moving component downwards into the rail system. When the direction of the force changes, the hook can slide in the recess until the opposite side of the hook rests against the opposite side of the recess. This allows the device to be supported both upwards and downwards by the rail system.

[0019] The locking device can have a cabin side and a counterweight side for connection to the rail system. The measuring device can be used on a cabin of the elevator system if the cabin side is connected to the rail system. Alternatively, the measuring device can be used on a counterweight of the elevator system if the counterweight side is connected to the rail system. A cabin guide of the rail system can differ from a counterweight guide of the rail system. The cabin side can be adapted to the cabin guide. The counterweight side can be adapted to the counterweight guide. The cabin side and the counterweight side can be connected to the rail system on different sides.

[0020] According to one embodiment, the device can be connected to the counterweight and / or the cabin by means of a screw device.

[0021] According to the claim, the device comprises a screw device with which, in the assembled state, a tensile force transmitted via load-bearing means to the at least one counterweight and / or the cabin can be changed.

[0022] According to the claim, the screw device has a thread, preferably a threaded rod, by means of which the counterweight and / or the cabin can be moved by a defined distance to change the pulling force. Preferably, the counterweight and / or the cabin can be raised by means of the screw device to reduce the pulling force. Preferably, alternatively or additionally, the counterweight and / or the cabin can be pushed or pulled downwards by the screw device to increase the pulling force.

[0023] The measuring device can be designed so that the force value can be transmitted as a signal to the elevator control system. This allows the device to be connected to the elevator control system. This enables at least partial automation of the processes in which the device's measuring device is used. This feature can be implemented, for example, via a wired connection and / or a wireless connection.

[0024] The device can be designed to include a display showing the force values ​​measured by the measuring device. Thus, when using the device to measure tensile forces, the force value set and displayed in a static state can be read and, for example, used by inputting it into the elevator control system.

[0025] An elevator system can be a passenger transport system. The elevator system can have at least one counterweight per cabin. In particular, the elevator system can have two counterweights per cabin. At least one load-bearing element is arranged between the cabin and the counterweights. The load-bearing element can be, for example, a rope or a belt. The load-bearing element can be guided over at least one traction sheave of a drive unit of the elevator system. The traction sheave can be arranged at an upper end of a rail system of the elevator system. The counterweights can move in the opposite direction to the cabin.

[0026] The rail system can have at least one guide per cabin and at least one guide per counterweight. In particular, the rail system can have two parallel, vertical guide rails between which the cabin is mounted so as to move vertically. Each guide rail can have a guide on its outer side for one of the counterweights.

[0027] The device can be temporarily connected to the rail system. It can also be connected to another static element, such as a rail bracket or a shaft wall. The device can be mechanically connected to the rail system. For example, it can be screwed or clamped to the guide rail. With two guide rails, the devices can be used in pairs. The guide rail can have at least one predefined attachment point for the device, allowing for a positive connection. The device can be connected to the elevator car in close proximity to the car brake. This allows the force measured by the measuring device to more accurately correspond to the actual force at the load sensor integrated into the car brake.The device can be positioned above or below the moving component.

[0028] A measuring device can be, for example, a load cell or a weighing beam. The measuring device can be positioned between an interface of the device to the rail system and an interface of the device to the moving component. An applied force can cause a slight elastic deformation of the measuring device. This deformation can be represented as an electrical signal. The signal can represent the force. The measuring device can be calibrated. For example, the measuring device can be zeroed before the moving component is fixed.

[0029] The pulling force can be increased or decreased.

[0030] The tensile force can be changed using a screw mechanism on the device. This screw mechanism can have a threaded section over which the movable component can be moved a defined distance to alter the tensile force. The component can be raised using the screw mechanism to decrease the tensile force. Likewise, the component can be pushed down or pulled down using the screw mechanism to increase the tensile force.

[0031] Alternatively or additionally, the tractive force can be varied by adjusting the torque supplied by the drive unit via the traction sheave. This torque can be varied via the drive unit's motor control unit. The torque can also be varied by applying a brake to the traction sheave. The magnitude of the change can be specified to the motor control unit and / or an actual change in torque can be measured and output by the motor control unit.

[0032] The component can be mechanically connected to the device attached to the rail system. The device can be connected to the rail system below the moving component and then mechanically connected to the moving component from below. This mechanical connection increases the tensile force of the load-bearing element without causing the component to lift off the device. Alternatively, the device can be connected to the rail system above the moving component and mechanically connected to the moving component from above. In this case, the moving component can be suspended from the device, thus relieving the load on the load-bearing element. The component can also be pressed downwards by the device. Furthermore, this mechanical fixation allows for safe work to be carried out on the elevator.

[0033] The procedure can begin by checking the weight of at least one counterweight and / or the cabin. A service technician can count the number of counterweight elements (e.g., concrete elements) for this purpose. In an elevator system with two counterweights, the service technician can ensure that both counterweights weigh the same. For example, they can count the number of counterweight elements of the first counterweight and the counterweight elements of the second counterweight and compare the numbers. If the number of counterweight elements is the same, it can be assumed that the counterweights weigh the same, meaning the system is balanced.

[0034] In a further step of the elevator control process, the completed test can be confirmed. Specifically, confirmation can be obtained by entering data into a mobile device connected to the elevator control system. For example, in an elevator system with only one counterweight, the service technician can enter the counterweight weight (number of counterweight elements) or confirm a target value displayed by the mobile device. In an elevator system with two counterweights, the service technician can confirm the balance of the counterweights by entering data into a mobile device connected to the elevator control system. The elevator control system thus knows the actual counterweight and the balance of the elevator system.

[0035] After placing the component on the service fixture, the elevator's brake can be activated. The drive unit can then be switched to torque-free operation. The brake can then be released to change the pulling force. Once a static state is established, the force value can be recorded. This force value can be compared to a reference value. The unloaded or empty cabin may be lighter than the counterweight(s). The ratio between the mass of the cabin and the mass of the counterweights can be described as the balance of the elevator system. The balance might be, for example, 4 / 6, in which case the cabin mass is approximately 66% of the counterweight mass. To check the balance, the counterweight or both counterweights can be placed on the service fixture.When the counterweight is placed on the elevator car, the drive unit compensates for the weight difference between the counterweight and the car by applying torque to the drive pulley. The brake is located on the car and blocks any movement of the elevator system, so that after the drive unit disengages, the entire load-bearing structure is subjected to the weight of the counterweight. The force sensor can now be zeroed and the brake released. When the brake is released, only the weight of the car is held by the load-bearing structure, as the weight difference between the counterweight and the car is held by the service device and reflected in the force reading. With two counterweights, each counterweight can be connected to the device(s) and measured using the described procedure. If it was determined in the previously described step that the two counterweights are of the same weight (e.g.,By counting the counterweight elements in each of the two counterweights, it may be sufficient to perform the described steps for one of the two counterweights. Then, knowing the identical weight of each counterweight, the total weight of both can be determined. The balance of the elevator system can be checked by comparing the determined total weight of the counterweights with a reference value.

[0036] The reference value can be determined based on the elevator system's balancing factor and the cabin's nominal weight. In particular, a reference range, corresponding to a tolerance range around the reference value, can be defined. The reference value can be calculated, for example, from a cabin weight and a balancing factor (both dependent on the elevator system type). For instance, the cabin's nominal weight (empty cabin) could be 610 kg and the balancing factor 4 / 6, resulting in a total counterweight weight of (610 / 4*6=) 915 kg. The device should therefore measure a force on the counterweight that corresponds to a weight of (915 / 2) 457.5 kg. To assess the elevator system's balance, a tolerance range around the reference value can be defined, within which the elevator system is considered balanced. For example, a tolerance range of + / -10% could be chosen.In this case, the elevator system is considered balanced if the force value measured corresponds to a weight of (+ / -10% of 457.5) 411.75 to 503.25 kg.

[0037] The device can be connected to the elevator control system via communication technology. At least one, preferably all, of the process steps from the list—setting up at least one counterweight and / or the cabin, changing a tensile force transmitted via the suspension means to the counterweight and / or the cabin, displaying a force value, activating the brake, deactivating the brake, torque-free switching of the drive unit, and / or comparison—can be executed by the elevator control system. This allows the balancing check procedure to be at least partially automated. For example, a service technician can initiate the process after attaching the device to the rail system by entering a command into a mobile device connected to the elevator system (i.e., the elevator control system). The elevator control system can then perform the aforementioned steps sequentially.The device can detect the counterweight's contact with the elevator via the measuring unit and communicate this detection to the elevator control system. The elevator control system can then initiate the next steps. In the next step, the elevator control system can activate the brake. After the elevator control system detects that the brake has engaged (for example, via a sensor on the brake), it can disengage the drive mechanism. As soon as a torque-free state is detected (e.g., by a current measurement in the elevator drive's inverter), the elevator control system can monitor the force applied to the device and wait for a static state. Upon reaching this static state, a force value is applied, and the elevator control system evaluates this value. This process can thus be automated and performed with minimal manual intervention by a service technician.

[0038] A load sensor can also be designed as a load cell or a load beam. The load sensor can be located at an interface between the lifting device and the cabin. The load sensor can be integrated into a braking system of the cabin. The cabin can also have multiple load sensors.

[0039] To calibrate the load sensor, a load value measured by the load sensor can be compared with a known value. If the load value deviates from the known value, a correction factor can be determined and the load value corrected using this factor.

[0040] It should be noted that some of the possible features and advantages of the invention are described herein with reference to different embodiments of methods on the one hand and of devices on the other. A person skilled in the art will recognize that the features can be suitably combined, adapted, or exchanged to arrive at further embodiments of the invention.

[0041] Embodiments of the invention are described below with reference to the accompanying drawings, whereby neither the drawings nor the description are to be interpreted as limiting the invention.

[0042] Fig. 1a and 1b show illustrations of a service device according to an exemplary embodiment; and

[0043] Fig. 2 shows a weight measurement according to an exemplary embodiment.

[0044] The figures are schematic only and not to scale. Identical reference symbols denote identical or equivalent features.

[0045] Fig. 1a Figure 1 shows a representation of a device 100 according to an exemplary embodiment. Fig. 1b shows an exploded view of device 100.

[0046] The device 100 comprises a locking device 102 and a measuring device 104. The locking device 102 is designed to be mechanically connected to a rail system of an elevator and to support or attach a component of the elevator system, such as a cabin or a counterweight, which is movably mounted on the rail system, to the rail system and to transfer a force from the movable component into the rail system. The measuring device 104 is designed to represent the force transferred from the movable component into the rail system via the locking device 102 as a force value 106.

[0047] The blocking device 102 has at least one rail interface 108 for connection to the rail system and at least one component interface 110 for connection to the component. The measuring device 104 is arranged between the rail interface 108 and the component interface 110.

[0048] The device 100 has a substantially cuboid housing 112 composed of stamped and bent parts. The housing 112 has two side panels 114 and two covers 116. The side panels 114 are U-shaped and are connected to one of the covers 116 at opposite end faces. The side panels 114 and the covers 116 enclose an interior space of the device 100. The side panels 114 and the covers 116 are made of metal.

[0049] The rail interface 108 has hooks 118 for engaging in corresponding recesses of the rail system. The hooks 118 are stamped from a sheet material. The hooks 118 are also made of metal. The hooks 118 protrude from slots 120 in the side parts 114 and can be inserted into corresponding elongated recesses of the rail system. After insertion, the hooks 118 can be moved along the recess until they grip an edge of the respective recess of the rail system and fix the device 100 to the edge.

[0050] The component interface 110 has a threaded rod 122. The threaded rod 122 is made of metal. The threaded rod 122 runs through the interior and through one hole 124 in each cover 116. At least two nuts 126 are screwed onto the threaded rod 122. The nuts 126 support the threaded rod 122 on at least one of the covers 116. The length of the threaded rod 122 protruding from the housing 112 can be varied. Different lengths of the threaded rod 122 can be set depending on the application.

[0051] The measuring device 104 is arranged on the threaded rod 122 between the nuts 126 and the cover 116.

[0052] The length of the threaded rod 122 can also be changed after the component is mounted on the device 100. In this case, the threaded rod 122 can be referred to as a screw device 127. The component can be moved a certain distance by changing its length. While the component is being moved, a tensile or compressive force is also exerted on it, which can be represented by the measuring device 104 as the force value 106.

[0053] Alternatively or additionally, the threaded rod 122 can also be screwed into a thread of the component. When used as a screw device 127, the threaded rod 122 can be turned in the thread of the component to move the component by the specified distance and to exert force on the component.

[0054] In one embodiment, the locking device 102 has two rail interfaces 108. The two rail interfaces 108 are arranged on opposite sides of the housing 112. One rail interface 108 is configured as the car side 128. The other rail interface 108 is configured as the counterweight side 130. When the car side 128 is connected to the rail system, the component interface 110 can be connected to the car of the elevator system. When the counterweight side 130 is connected to the rail system, the component interface 110 can be connected to the counterweight of the elevator system.

[0055] In one embodiment, the hooks 118 on the cabin side 128 are designed as symmetrical double hooks. The double hooks can thus transfer forces acting on the locking device 102 from opposite directions into the rail system.

[0056] In one embodiment (not shown), the device 100 has an interface for communication with an elevator control system. This interface can be implemented, for example, as a wireless connection or a wired connection. In another embodiment, the device 100 has a display for showing the measured values ​​measured by the measuring device 104. In a further alternative embodiment, the measured values ​​are transmitted wirelessly to a display unit. This display unit can be a smartphone.

[0057] Fig. 2 Figure 1 shows a weight measurement according to an exemplary embodiment. The weight measurement is performed using a service device 100 according to the approach presented here. The service device 100 essentially corresponds to the service device in Figure 1. Fig. 1The weight measurement is shown here on a counterweight 200 as the moving component 202 of an elevator system 204, but can also be carried out analogously on a cabin of the elevator system 204.

[0058] For weight measurement, the locking device 102 of the service device 100 is mechanically connected to a rail 206 of a rail system 208 of the elevator system 204. For this purpose, the hooks 118 of the concealed counterweight side of the rail interface 108 of the locking device 102 are engaged in recesses 210 of the rail 206. The locking device 102 thus blocks a travel path of the counterweight 200 along the rail 206. The measuring device 104 is arranged on the upper side of the service device 100.

[0059] For measurement, the counterweight 200 is slowly placed onto the threaded rod 122 of the component interface 110 by a drive unit of the elevator system 102, by lifting the cabin. During placement, at least a portion of the counterweight 200's weight force 212 is transferred via the service device 100 into the rail system 208. This portion can become large enough to establish a static equilibrium between the weight force of the cabin and the remaining weight force 212 of the counterweight 200. This portion of the weight force 212 can then be measured by the measuring device 104.

[0060] The counterweight 200 can also be lowered only to the point where the component interface 110 and the counterweight 200 just touch. Then, a brake of the elevator system 204 can be activated and the drive unit switched to torque-free operation. After the brake is released, static equilibrium is established as the counterweight 200 settles until the excess weight of the counterweight 200 is transferred via the service device 100 into the rail system 208 and detected by the measuring device 104. In this way, the weight difference between the counterweight(s) and the cabin (also called balancing) resulting from the weight difference selected for the elevator system can be measured.

[0061] After the counterweight 200 is placed on the counterweight, the drive unit can continue to lift the cabin until a load-bearing element between the drive unit and the counterweight 200 becomes slack. Upon slackening, the tensile force of the load-bearing element is reduced to approximately zero. The weight force 212 of the counterweight 200 is now transferred almost completely to the rail 206 by the locking device 102. The measuring device 104 can then represent the full weight force 212 in the force value 106.

[0062] After the measurement, the lifting element is tensioned by the drive unit by lowering the cabin again and increasing the tensile force in the lifting element until the counterweight 200 lifts off the component interface 110 again. The service device 100 is then removed from the rail 206. The measurement process can now be repeated on the other counterweight of the cabin.

[0063] The measuring device can also be removed from the apparatus, and the locking device can be used without the measuring device as a safety device to fix one of the moving components. This allows, for example, maintenance work to be carried out safely on the elevator system.

[0064] Finally, it should be noted that terms such as "comprising," "encompassing," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality. Furthermore, it should be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps from other embodiments described above. Reference numerals in the claims are not to be considered as limitations.

Claims

1. An apparatus (100) for a lift installation (204), wherein the apparatus (100) has a blocking mechanism (102) and a measuring mechanism (104), wherein the blocking mechanism (102) is configured to connect a counterweight and / or a lift car of the lift installation (204) to a rail system (208) of the lift installation (204) and / or to support it on the rail system (208), wherein the measuring mechanism (104) is configured to map a force transferred from the counterweight and / or lift car into the rail system (208) as a force value (106), characterized in that the device (100) can be connected to the counterweight (200) and / or the car (302) by means of a screw device (127); and when the device (100) is assembled, the tensile force (306) transmitted to the at least one counterweight (200) and / or the car (302) via support means (308) can be varied by means of the screw device (127); and the screw device (127) has a thread, preferably a threaded rod (122), by means of which the counterweight (200) and / or the car (302) can be moved by a defined distance in order to change the tensile force (306), whereby preferably the counterweight (200) and the car (302) are lifted via the screw device in order to reduce the tensile force (306), whereby the counterweight (200) and / or the car (302) are preferably pressed down or pulled down by the screw device in order to increase the tensile force (306).

2. The apparatus (100) according to claim 1, wherein the blocking mechanism (102) comprises at least one hook (118) to be inserted into a corresponding recess (210) in the rail system (208).

3. The apparatus (100) according to claim 2, wherein the hook (118) is designed to be symmetrical and is configured to be inserted into the recess (210) in opposite orientations.

4. The apparatus (100) according to any of claims 1 to 3, wherein the blocking mechanism (102) has a car side (128) and a counterweight side (130) for connecting to the rail system (208), wherein the measuring mechanism (104) is configured to be used on a car (302) of the lift installation (204) when the car side (128) is connected to the rail system (208), or the measuring mechanism (104) is configured to be used on a counterweight (200) of the lift installation (204) when the counterweight side (130) is connected to the rail system (208).

5. The apparatus (100) according to any of the preceding claims, wherein the measuring mechanism (104) is configured such that the force value is transmittable in the form of a signal to an elevator controller of the lift installation (204).

6. A method for checking the balancing of a lift installation (204), wherein the lift installation (204) comprises at least one elevator controller, at least one guide rail and at least one counterweight and a car, wherein the at least one counterweight is connected to the car via at least one support means, the method comprising the steps of: - connecting at least one apparatus (100) according to claims 1 to 5 to the at least one guide rail; - placing the at least one counterweight and / or the car onto the at least one apparatus (100); - changing a tensile force transmitted to the at least one counterweight and / or the car via support means; - recording a force value on the basis of a force transferred to the rail system via the apparatus.

7. The method according to claim 6, wherein the tensile force (306) is varied using a screwing apparatus (127) of the device (100); and / or wherein the tensile force (306) is varied using a drive unit of the lift installation (204).

8. The method according to any of claims 6 to 7, wherein the at least one counterweight and / or the car is mechanically connected to the apparatus (100).

9. The method according to any of claims 6 to 8, wherein in a first step the weight of the at least one counterweight and / or the car is tested.

10. The method according to claim 9, wherein in a further method step the elevator controller confirms the test carried out, wherein the confirmation is confirmed in particular via an input in a mobile device connected to the elevator controller.

11. The method according to claims 6 to 10, wherein, after the at least one counterweight and / or the car has been placed on the apparatus (100), a brake of the lift installation (204) is activated and a drive unit of the lift installation (204) is switched torque-free, wherein the brake is then released in order to change the tractive force (306) and, after a static state has been set, the force value (106) is detected, wherein the force value (106) is compared with a reference value.

12. The method according to claim 11, wherein the reference value is determined as a function of a balancing factor of the lift installation and a desired car weight, wherein in particular a reference range corresponding to a tolerance range around the reference value is determined.

13. The method according to any of claims 6 to 12, wherein the apparatus is connected to the elevator controller by means of communication technology, wherein at least one, preferably all, of the method steps from the list can be carried out by the elevator controller: placing at least one counterweight and / or the car, changing a tensile force transmitted to the counterweight and / or the car via the support means, mapping a force value, activating the brake, deactivating the brake, switching the drive unit without torque and / or comparing.

14. A lift installation having at least one, preferably two counterweights, a car and an elevator controller, wherein the elevator controller is configured to connect to an apparatus according to any of claims 1 to 5 and to carry out a method according to any of claims 6 to 13.