METHOD FOR DETERMINING A WEAR STATE OF COMPONENTS OF A SUSPENSION MEANS ARRANGEMENT OF AN ELEVATOR SYSTEM

Abstract

A method and a monitoring device determine a wear state of components such as a cable-like suspension means, a traction sheave of a drive machine and deflection rollers of a suspension means arrangement of an elevator system. The method comprises at least the following steps: monitoring an actual time curve of a first parameter which correlates with the wear state of at least one first monitored component of the components; comparing the actual time curve of the monitored first parameter with a predetermined expected time curve of the first parameter; and determining the wear state of the monitored component based on a result of the comparison.

Claims

1-15. (canceled)

16. A method for determining a wear state of components of a suspension means arrangement of an elevator system, the method comprising steps of: generating an actual time curve by monitoring a first parameter that correlates with a wear state of a first monitored component of the components of the suspension means arrangement; comparing the actual time curve of the first parameter with a predetermined expected time curve of the first parameter; and determining the wear state of the first monitored component based on a result of the comparison, wherein the wear state is determined based on an incipient decrease in a modulus of elasticity of a cable-like suspension means of the suspension means arrangement after a preceding successive increase in the modulus of elasticity of the suspension means.

17. The method according to claim 16 wherein the suspension means arrangement includes: the suspension means; a traction sheave driven by a drive machine for moving the suspension means resting on a contact surface of the traction sheave; at least one anchoring fixing the suspension means on an elevator car to be moved by the suspension means arrangement and/or in an elevator shaft accommodating the suspension means arrangement; and wherein the first parameter being monitored is selected from a group of parameters including a length of the suspension means, elongation properties of the suspension means, radial dimensions of the suspension means, optical properties of the suspension means, magnetic properties of the suspension means, electrical properties of the suspension means, a mechanical stress on the suspension means, dimensions of a structure of the contact surface of the traction sheave, a slip occurring between the suspension means and the contact surface of the traction sheave, and a force exerted by the suspension means on the at least one anchoring.

18. The method according to claim 16 further comprising steps of: generating another actual time curve by monitoring a second parameter that influences the wear state of the first monitored component and/or correlates with the wear state of the first monitored component, wherein the second parameter differs from the first parameter; and determining the wear state of the first monitored component based both on the result of comparing the actual time curve with the predetermined expected time curve of the first parameter and on a result of the another actual time curve of the monitored second parameter.

19. The method according to claim 18 wherein the first parameter and the second parameter correlate with the wear state of the first monitored component in different ways.

20. The method according to claim 18 wherein the first parameter and the second parameter correlate with the wear state of the first monitored component in a mutually interactive manner.

21. The method according to claim 18 wherein, based on measurement results of the monitored second parameter, the predetermined expected time curve of the first parameter is selected from a plurality of possible predetermined expected time curves of the first parameter.

22. The method according to claim 18 wherein the second parameter being monitored is selected from a group of parameters including: a temperature in a region of the suspension means arrangement; a humidity in the region of the suspension means arrangement; and an air pressure in the region of the suspension means arrangement.

23. The method according to claim 18 wherein the second parameter being monitored indicates a frequency of journeys of an elevator car moved by the suspension means arrangement.

24. The method according to claim 16 wherein the wear state is determined based on a deviation of the actual time curve of the first parameter from the predetermined expected linear time curve of the first parameter.

25. The method according to claim 16 wherein the wear state is determined based on a reversal of a property of the actual time curve of the first parameter compared to a previous actual time curve of the first parameter.

26. The method according to claim 16 wherein the wear state is determined based on a sign change of a second time derivative of the actual time curve of the first parameter compared to a second time derivative of a previous actual time curve of the first parameter.

27. The method according to claim 16 wherein the predetermined expected time curve of the first parameter is predetermined on a basis of a plurality of measured values that were determined in different elevator systems.

28. A monitoring device for determining a wear state of components of a suspension means arrangement of an elevator system, wherein the monitoring device is adapted to carry out or control the method for determining according to claim 16.

29. A computer program product containing computer-readable instructions that, when executed on a computer, instruct the computer to carry out or control the method for determining according to claim 16.

30. A non-transitory computer-readable medium having the computer program product according to claim 29 stored thereon.

Description

DESCRIPTION OF THE DRAWINGS

[0110] FIG. 1 shows a monitoring device for determining a wear state of components of a suspension means arrangement in an elevator system according to an embodiment of the present invention.

DETAILED DESCRIPTION

[0111] FIG. 1 shows an elevator system 1 in which a wear state of components of a suspension means arrangement 5 can be determined by means of a monitoring device 3.

[0112] The elevator system 1 has a car 7 and a counterweight 9, which can be moved vertically between different floors 13 within an elevator shaft 11. The car 7 and the counterweight 9 can be held and moved by means of the suspension means arrangement 5. For this purpose, the suspension means arrangement 5 has a plurality of cable-like suspension means 15 such as cables, straps or belts. The suspension means 15 can be driven with a traction sheave 17 of a drive machine 19. For this purpose, the traction sheave 17 can have a structure which is adapted to a geometry of the suspension means 15, for example in the form of grooves, channels or the like, on a contact surface 21 on which the suspension means 15 rest on the traction sheave 17. In the example shown, the suspension means 15 are fixed to a ceiling 25 of the elevator shaft 11 via anchorings 23. From there, the suspension means 15 extend down to the deflection rollers 27, 29, which are attached to the car 7 or the counterweight 9, in order to then extend back up to the traction sheave 17 of the drive machine 19. An operation of the drive machine 19 is controlled by an elevator controller 31. The elevator controller 31 can communicate with the monitoring device 3.

[0113] A large number of sensors or sensor systems are provided in the elevator system 1, by means of which parameters can be monitored, which allow a conclusion to be drawn about states or properties within the elevator system 1 that correlate with or influence states of wear of components of the suspension means arrangement 5. These sensors or sensor systems can be wired to the monitoring device 3 or designed to be able to communicate wirelessly with the monitoring device 3, in order to be able to transmit measurement data or measurement signals which represent parameters measured by the sensors or sensor systems to the monitoring device 3.

[0114] For example, a length measurement sensor system 35 is provided at a lower end of the elevator shaft 11 in the vicinity of a buffer 33 adjacent to a travel path of the counterweight 9. A distance between the counterweight 9 and the buffer 33 can be determined by means of this length measurement sensor system 35 when the counterweight 9 is located in the lowest possible position thereof, i.e. when the car 7 is located on the highest possible floor 13. A current length of the suspension means 15, which can change over time, in particular due to material elongation, can be indirectly inferred from the measurement of this distance.

[0115] Radial dimensions of the suspension means 15, i.e. a diameter of suspension cables or a thickness of suspension belts, for example, can be measured using a sensor system specially adapted for this purpose. For example, a camera 37 can be used for this purpose, the field of view of which is directed towards the suspension means 15. Optionally, this camera 37 can alternatively or additionally also be used to detect optical properties of the suspension means, such as a change in surface textures on the suspension means and/or a change in color, reflectivity, etc.

[0116] Furthermore, a sensor system 39 can be provided for measuring magnetic properties of the suspension means 15. By means of this sensor system 39, a magnetic flux through one of the suspension means 15 can be measured, for example.

[0117] Additionally or alternatively, a sensor system 41 can be provided for measuring electrical properties of the suspension means 15. This sensor system 41 can, for example, measure electrical current flows or an electrical resistance through one of the suspension means 15.

[0118] The anchorings 23 can be designed as intelligent fixed points and configured to measure mechanical stresses on or in the suspension means 15. For example, strain gauges can be provided in the anchorings 23, which interact with the suspension means 15 or the anchored ends thereof. The anchorings 23 can optionally also be designed to measure forces exerted by the suspension means on the anchorings 23.

[0119] Furthermore, a sensor system 43 can be provided, by means of which dimensions of a structure of the contact surface 21 of the traction sheave 17 can be monitored. Such a sensor system 43 can, for example, in turn be implemented using a camera or other optical sensors, but sensors which function in a different manner can also be used.

[0120] In addition, the monitoring device 3 can receive data and information, on the basis of which other parameters which correlate with the wear of components of the suspension means arrangement 5 can be inferred, from the elevator controller 31 and/or other sensors 45, which can be used, for example, to determine a current position of the elevator car 7 in the elevator shaft 11.

[0121] For example, it is possible to infer elongation properties of the suspension means 15 from a way in which level adjustments are carried out by the elevator controller 31 when the elevator car 7 stops at a floor 13, i.e. how often and/or over what distance, for example.

[0122] By comparing a controlled movement distance, which was controlled by the drive machine 19 by means of the elevator controller 31, with an actual movement distance of the car 7 or the counterweight 9, as can be detected, for example, using the signals from the sensors 45, it is also possible to infer a slip occurring between the suspension means 15 and the contact surface 21 of the traction sheave 17.

[0123] Furthermore, a temperature sensor 47, a humidity sensor 49 and/or an air pressure sensor 51 can be provided in the elevator shaft in order to be able to measure corresponding prevailing conditions in the region of the suspension means 15.

[0124] The monitoring device 3 is configured to carry out a method using measurement data, as can be provided by at least one of the sensors or sensor systems described above, by means of which method information can be determined about a current and/or a future wear state of components of the suspension means arrangement 5.

[0125] For this purpose, the monitoring device 3 typically has a data processing device such as a data processor and a data memory in which measurement data can be stored and retrieved again at a later point in time, and data interfaces via which the monitoring device 3 can exchange data with the various sensors and sensor systems, for example.

[0126] Within the scope of the method, an actual curve of a first parameter is monitored continuously or at predetermined time intervals, for example by collecting and tracking measurement data from one or more of the sensors and sensor systems. The first parameter is selected in such a way that it correlates with the wear state of at least one of the components of the suspension means arrangement 5. The actual time curve of the first parameter monitored in this way is then compared with a predetermined expected time curve of this parameter, and the wear state of the monitored component is then determined based on a result of this comparison.

[0127] For example, the current length of the suspension means 15 can be determined as the first parameter based on the data provided by the length measuring sensor system 35. By accumulating the data over a certain time period, information can be derived about the actual time curve of this parameter, i.e. how the length of the suspension means 15 changes over time.

[0128] An expected time curve, which indicates how the length of the suspension means typically changes over time, can be predetermined from previously conducted experiments, simulations and/or knowledge obtained from other elevator systems. By comparing the actual time curve of the length behavior of the suspension means 15 with the expected time curve, a statement can then be determined about the current and/or a future wear state of the suspension means 15.

[0129] For example, it can be detected that the observed suspension means 15 lengthen faster over time than is known from the suspension means used as a reference and would thus be expected. This information can be used in order to be able to infer a progressing wear state and/or, for example, a point in time at which the suspension means 15 will have reached a permissible wear limit.

[0130] A second parameter is preferably also monitored in addition to the monitoring of the first parameter. Like the first parameter, this second parameter can correlate with the wear state of the monitored component. However, it may be preferable for the second parameter to even influence the wear state, i.e. a statement can be derived therefrom as to how the wear state changes over time.

[0131] Many different combinations of first and second parameters to be monitored are conceivable or advantageous. It may be advantageous, for example, to select the two parameters to be monitored to be dependent on one another. In particular, it may be advantageous to select the way in which the first parameter is monitored or evaluated to be dependent on a selection of the second parameter and/or dependent on actual time curves of the second parameter.

[0132] For example, a temperature prevailing in the elevator shaft 11 or prevailing directly on the suspension means 15 can be monitored as a second parameter, for example by means of the temperature sensor 47. The wear state of the suspension means 15 can then be determined in the aforementioned example based on the comparison of the actual curve of the length of the suspension means 15 and additionally on the actual curve of the measured temperature. The fact that a temperature prevailing over a longer time period has an influence on the wear occurring in the suspension means 15 and the wear can in turn be reflected in a change in the length of the suspension means 15 can be used in this case. An expected time curve of the changes in length in the suspension means 15 can in this case be predetermined based on the actual curve of the temperatures.

[0133] In this case, of a plurality of possible predetermined expected time curves of the changes in length, which were calculated, simulated, experimentally determined or observed in other systems for different temperatures prevailing during a monitoring period, the expected time curve of the changes in length that resulted for the actual time curve of the temperature conditions can be used for comparison with the actual curve of the changes in length.

[0134] In general, information about the current and/or future wear state of components of the suspension means arrangement 5 can in particular be determined based on detected deviations of the actual time curve of the monitored first parameter from a predetermined expected time curve of this parameter that can be assumed to be linear, for example. Reversals of properties of the actual time curve of the monitored parameter or sign changes of a second time derivative of the actual curve of the monitored parameter can provide a good indication or a good data basis for determining the wear state of the monitored component.

[0135] In a special variant of the proposed method, the expected time curve of the first parameter can be predetermined based on a large number of measured values which were measured in various other elevator systems 53. For this purpose, the monitoring device 3 can communicate with a server 55, for example, which can receive such measured values from the other elevator systems 53 and, if necessary, evaluate and/or temporarily store the values. The server 55 can, for example, be part of a data cloud (cloud) and/or can be arranged in a control center which monitors a large number of elevator systems 53.

[0136] Finally, it should be noted that terms such as “comprising,” “having,” etc. do not preclude other elements or steps, and terms such as “a” or “an” do not preclude a plurality. Furthermore, it should be noted that features or steps which have been described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above.

[0137] In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.