EP4065499A1

EP4065499A1 - Method for determining a wear state of components of a suspension means arrangement of an elevator system

Info

Publication number: EP4065499A1
Application number: EP20811376.1A
Authority: EP
Inventors: Florian Dold
Original assignee: Inventio AG
Current assignee: Inventio AG
Priority date: 2019-11-29
Filing date: 2020-11-27
Publication date: 2022-10-05
Anticipated expiration: 2040-11-27
Also published as: US20230002194A1; KR20220101109A; JP2023503516A; EP4065499B1; CN114728766A; WO2021105347A1

Abstract

The invention relates to a method and to a monitoring apparatus for determining a wear state of components such as a rope-like suspension means (5), a sheave (17) of a prime mover (19) and pulleys (27, 29) of a suspension means arrangement (5) of an elevator system (1). The method comprises at least the following steps: - monitoring an actual temporal progression of a first parameter which correlates to the wear state of at least one first of the monitored components - comparing the actual temporal progression of the monitored first parameter to a predetermined expected temporal progression of the first parameter; - determining the wear state of the monitored components on the basis of an outcome of the comparison.

Description

Method for determining a state of wear of components of a suspension element arrangement of an elevator installation

description

The present invention relates to a method with the aid of which a state of wear of components of a suspension element arrangement in an elevator installation can be determined. The invention also relates to a monitoring device for executing or controlling such a method, a computer program product for programming such a monitoring device and a computer-readable medium with such a computer program product.

In an elevator system, a suspension element arrangement is used to move an elevator car and, if necessary, a counterweight within an elevator shaft and, as a rule, also to hold their weight.

In general, the suspension element arrangement comprises a plurality of elongate, flexible suspension elements such as, for example, ropes, belts or belts. Ropes can be composed of a large number of wires or strands, which are usually made of metal, in particular steel. Belts or belts can also have wires or strands, for example made of steel or fiber materials, as load-bearing elements, which are accommodated in a matrix material such as for example a polymer or elastomer.

Depending on the type of suspension implemented in an elevator system, these suspension elements can be anchored to the elevator car and / or the counterweight in order to hold them. Alternatively, the support means can be anchored in the elevator shaft, for example on a shaft ceiling, and hold the elevator car and / or the counterweight via deflection pulleys attached to them, which are often also referred to as pulleys.

The suspension means are mostly moved by a drive machine in order to be able to move the elevator car held by them and the counterweight in opposite directions within the elevator shaft. The suspension elements run in the Generally via a drive pulley driven in rotation by the drive machine. Depending on the type of suspension used, the traction sheave can have a profiled surface. For example, the traction sheave for suspension elements can be designed in the form of ropes with circumferential grooves in which the ropes can engage in order to achieve sufficient traction between the traction sheave and the ropes. In the case of suspension elements in the form of belts or belts, these can have a profiled surface, for example a V-shaped toothed surface, and the traction sheave can have a complementarily profiled surface on its outer surface.

The components mentioned, i.e. in particular the suspension elements, the drive machine with its traction sheave, the deflection rollers and the anchorages of the suspension elements, as well as other components, can together form the suspension element arrangement.

During the operation of an elevator system, the components of the suspension element arrangement usually wear.

For example, suspension elements can gradually lose their mechanical strength due to friction with the traction sheave or the deflection rollers and / or as a result of frequent bending during deflection by the traction sheave or the deflection rollers. The wear and tear can be the result of material abraded on the surface and / or material fatigue and possibly material breaks. Wear on suspension elements usually leads to a change in their physical properties. In particular, wear on the suspension elements can lead to a reduced load-bearing capacity of these suspension elements. In the worst case, suspension elements can tear. In addition, wear and tear on suspension elements can affect their elasticity. For example, suspension means can become more elastic or softer over time, so that it can be difficult, for example, to precisely position an elevator car held thereon by means of these suspension means.

Signs of wear can also occur on the traction sheave and the deflection pulleys. For example, profiling a jacket surface of these components can change their structure over time, in particular due to abrasion. Wear-related changes to the traction sheave or the deflection pulleys can be added, among other things lead that a frictional connection between these components and the suspension means driven or guided by them changes. For example, a slip between the traction sheave and driven suspension elements can increase over time due to wear, especially if the expansion module changes. A lateral guidance of suspension elements caused by the traction sheave and / or the deflection rollers can also decrease due to wear. In addition, when the diameter of the suspension element decreases, the conveying radius is reduced and more revolutions of the traction sheave are required over the service life for the same route between two specific floors.

Various other types of wear and tear can also occur, which can cause other types of changes in the physical properties of the suspension element arrangement.

Various approaches have been developed in order to limit or monitor the wear of components within an elevator installation, in particular the wear of components of the suspension element arrangement. In EP 3 130 555 A1,

CN 104627762 A, WO 2018/139434 A1, CN 109987480 A, JP 2011-132010 A,

EP 2299251 A1, EP 0 849208 A1, JP 2011-126710, WO 2019/081412 A1,

WO 2003/035531 A1, WO 2007/141371 A2, JP 2019-085242 A, EP 2 628 698 B1 and WO 2016/040452 A1 describe some of these approaches.

Among other things, there may be a need for a method with the aid of which wear on components of a suspension element arrangement can be monitored more efficiently, more reliably and / or more cost-effectively. Furthermore, there may be a need for a monitoring device set up to carry out or control such a method, a corresponding computer program product and a computer-readable medium storing this.

Such a need can be met by the subjects according to the independent claims. Advantageous embodiments are defined in the dependent claims and the description below. According to a first aspect of the invention, a method for determining a state of wear of components of a suspension element arrangement of an elevator system is proposed, the method having at least the following method steps, preferably in the specified order:

Monitoring of an actual time profile of a first parameter which correlates with the wear state of at least one of the first monitored components

- comparing the actual time profile of the monitored first parameter with a predetermined expected time profile of the first parameter;

- Determining the state of wear of the monitored component based on a result of the comparison.

According to a second aspect of the invention, a monitoring device for determining the state of wear of components of a suspension element arrangement of an elevator installation is proposed, which is configured to execute or control an embodiment of the method according to the first aspect of the invention.

According to a third aspect of the invention, a computer program product is proposed which contains computer-readable instructions which, when executed on a computer, in particular a computer-like programmable monitoring device according to the second aspect of the invention, instruct the latter to carry out the method according to an embodiment of the first aspect of the invention or control.

According to a fourth aspect of the invention, a computer-readable medium is proposed on which a computer program product according to the third aspect of the invention is stored.

Possible features and advantages of embodiments of the invention can be viewed, inter alia and without restricting the invention, as being based on the ideas and findings described below.

In conventional approaches with which the wear of components of a suspension element arrangement is to be monitored, a parameter is typically that Conclusions about this wear enabled, monitored. For example, the dimensions of the suspension elements, that is to say, for example, the diameter of a rope, are monitored. As further examples, surface structures on the traction sheave or the deflection pulleys, magnetic fluxes through suspension elements, an expansion behavior of suspension elements or a slip between suspension elements and, for example, the traction sheave can be monitored. As a rule, a current measured value of the parameter is used to infer a current state of wear of the respective component. For example, the current measured value is compared with a predetermined limit value and if the limit value is exceeded or undershot, a conclusion is drawn that the monitored component has reached a critical state of wear.

In the approach presented here, however, a single measurement of a parameter at a single point in time should not be used in order to determine the state of wear of a component of the suspension element arrangement. Instead, a parameter should be monitored over time. In other words, the aim is to track how the monitored parameter changes over time. To this end, it is generally necessary to measure the monitored parameter continuously or at time intervals, for example periodically, and to keep track of the measured values obtained, i.e. to store them, for example.

The time course of the parameter determined in this way should then not be compared with a single limit value or the like, as is the case with conventional approaches. Instead, the determined time profile should be compared with a predetermined expected time profile of this parameter.

Such an expected time course of the parameter can have been determined beforehand, for example based on experiments, data that were collected from other elevator systems and their suspension element arrangements, simulations or the like. Alternatively or additionally, an expected course of the parameter over time can also have been determined based on a course of the parameter observed earlier on the same component, that is to say for example by extrapolating a previously determined course of the parameter. By comparing the actual time profile of the monitored parameter with the predetermined expected time profile of the parameter, information about the current state of wear and / or possibly also information about a future state of wear of the observed component of the suspension element arrangement can then be determined.

This approach is based on the observation that a state of wear of a component of the suspension arrangement is in some cases not necessarily reflected in the current physical properties of this component and can thus be determined by measuring a parameter that correlates with it, or that information about a future state of wear is found in some Do not allow cases to be deduced solely from parameters measured at a single point in time. Instead, it has been observed that monitoring a behavior over time with which the physical properties of these components change can enable more reliable and / or more precise conclusions to be drawn about current and, in particular, future wear states of the components.

The parameter to be monitored with regard to its actual temporal course within the scope of the approach described here is intended to correlate with the wear state of at least one first monitored component of the plurality of components in the suspension element arrangement. Such a correlation can be expressed in that the parameter changes its value as a function of the current state of wear of the monitored component, preferably changes in a clearly determined manner.

Since, as explained in more detail below, it can be advantageous in some embodiments to monitor yet another parameter, the parameter to be monitored in all embodiments is referred to herein as the first parameter and the further parameter to be monitored additionally in some embodiments is referred to as the second parameter.

According to one embodiment, the first parameter to be monitored is selected from the group of parameters comprising:

- a length of the suspension element,

- elongation properties (reversible and / or irreversible) of the suspension element, - radial dimensions of the suspension element,

- optical properties of the suspension element,

- magnetic properties of the suspension element,

- electrical properties of the suspension element,

- a mechanical tension of the suspension element,

- dimensions on a structure of the contact surface of the traction sheave,

- A slip that occurs between the suspension element and the contact surface of the traction sheave, and

- a force caused by the suspension element on the anchorage, in particular also

- Temporal progression of vibrations or micro-accelerations, which can be assigned to the suspension element based on its structure. e.g. a shift in the length of the rope lay, and in particular

- Change in the natural frequency of the elevator system (car and / or counterweight) in the longitudinal direction of the shaft at a given position (due to the acceleration sensor, car mass remains the same, therefore inferring the belt), and in particular

- Evaluation of the readjustments of the elevator car, and in particular

- Ambient temperature (main driver of plastic aging), and in particular

- Air humidity (main driver of plastic aging).

Each of the parameters mentioned correlates to a certain extent with the current state of wear of a component of the suspension element arrangement. At best, a parameter or its course over time also correlates with a future state of wear of the component. The individual parameters can be measured in different ways and can correlate in different ways with states of wear of the same component or different components of the suspension element arrangement. The parameters mentioned can be measured in a relatively simple and / or precise manner, preferably using measuring devices that are structurally simple and thus more cost-effective and / or provided in any case in an elevator system.

The length of the suspension element, that is to say a distance between ends of the suspension element that are anchored, for example, in the elevator shaft or on one of the components to be moved with the suspension element, often depends heavily on the state of wear of this suspension element. Typically, the length of the suspension element increases increasing wear. The length of the suspension element can be measured in different ways, directly or indirectly. For example, a distance between the counterweight held by the suspension element and a buffer provided on the floor of the elevator shaft can be measured when the elevator car is on the top floor. This distance becomes smaller, the longer the suspension element is. This distance can be measured relatively easily and thus allows an exact conclusion about the current length of the suspension element.

The elongation properties of the suspension element, i.e. a way in which the suspension element can be lengthened in response to the forces exerted on it, also depend heavily on the state of wear of the suspension element. The elongation properties of the suspension element can be represented by its modulus of elasticity. They can refer to an elasticity of extension and / or an elasticity of bending. The elongation properties can be measured directly, for example by measuring changes in length of the suspension element with known mechanical loads. The elongation properties of suspension elements can also be determined directly, for example, with the aid of strain gauges or the like attached to the suspension elements. Alternatively or in addition, the elongation properties can be measured indirectly, for example by monitoring how strongly and / or how often a so-called level compensation has to be carried out. With such a level adjustment, the elevator car is stopped at a target position and then changes its level, that is to say its height in the elevator shaft, when the car is loaded or unloaded due to the associated changes in length of the suspension elements. The change in level is then compensated for by appropriately displacing the suspension elements with the drive machine. The strength and / or frequency with which such a level adjustment must be carried out can enable a conclusion to be drawn about the current expansion properties of the suspension elements.

The elongation and, accordingly, the modulus of elasticity also correlate with the natural frequency of the system. Thus, by measuring the natural frequency, conclusions can be drawn about the modulus of elasticity and, conversely, by determining the elastic modulus, conclusions can be drawn about the natural frequency. The radial dimensions of suspension elements, that is, for example, a diameter of a rope or a thickness of a belt, can decrease over time due to wear, in particular due to abrasion, and thus represent a suitable measure for determining the current state of wear of suspension elements Suspension means can be measured directly or indirectly. For example, the radial dimensions can be determined using optical sensors. A decrease in the radial dimensions of a suspension element beyond a certain amount can be an indication that the suspension element is ready for discard, ie that the suspension element should be replaced.

The optical properties of the suspension element can also change over time due to wear and tear. For example, increasing wear can change a color, reflectivity and / or optically recognizable structures such as surface roughness or macroscopic structures on the surface of the suspension element, for example in the form of protruding wires of a rope. The measurement of the optical properties of the suspension element can thus enable a relatively simple conclusion to be drawn about its state of wear. The optical properties of a suspension element can be monitored with suitable sensors such as light sensors, photodiodes, cameras, etc.

The magnetic properties of the suspension element also frequently correlate strongly with its state of wear. In the case of ferromagnetic suspension elements in particular, increasing wear can have a considerable influence on the magnetic flux occurring in the suspension element. A measurement of the magnetic flux through the suspension element, which can be carried out relatively easily, can thus be used to draw conclusions about its state of wear.

In many cases, the electrical properties of the suspension element are also influenced by its state of wear. In particular in the case of suspension elements with good electrical conductivity, such as steel cables or belts with load-bearing steel strands, increasing wear can have a considerable influence on an electrical resistance caused by the suspension element. For example, with increasing wear, breaks or cracks in individual strands of the many strands in a suspension element can lead to the electrical resistance that is passed through the suspension element electric current increases over time. A measurement of the electrical resistance through the suspension element, which is relatively easy to carry out, can thus be used to draw conclusions about its state of wear.

The mechanical tension acting in the suspension elements during the operation of the elevator installation can also depend on the state of wear of the suspension elements. In particular for the typical case in which the elevator car and the counterweight are held and displaced with the aid of a plurality of suspension elements, wear can have the effect that individual suspension elements change more in length than others. The forces to be held by the individual suspension elements and thus the mechanical stresses acting in the suspension elements change accordingly over time. Such mechanical stresses can be measured relatively easily and thus enable conclusions to be drawn about signs of wear.

While the parameters discussed above mainly relate to the determination of a state of wear of the suspension element, other parameters can be monitored in order to be able to detect wear on other components of the suspension element arrangement.

For example, dimensions on a structure of the contact surface of the traction sheave can change with increasing wear. The traction sheave can have structures such as, for example, grooves, grooves, webs, axial side boundaries, etc. on its contact surface, ie typically on its lateral surface where the suspension elements come into contact with the traction sheave. These structures can be designed to move the suspension elements with the aid of the traction sheave with a desired traction or a desired slip and / or to guide them laterally. Over time, these structures can wear out due to wear, ie change in their dimensions. For example, grooves on the outer surface of the traction sheave can wear out over time, in particular become rounded or change in terms of their depth. Monitoring the dimensions of such structures can thus enable conclusions to be drawn about a state of wear of the traction sheave. Since the traction sheave also interacts with the suspension elements, a state of wear of the suspension elements can optionally also be inferred indirectly. The slip that occurs between the suspension elements and the contact surface of the traction sheave can also change over time as a result of wear. This can result as a result of the aforementioned changes in the dimensions of the structures on the contact surface of the traction sheave. However, there can also be other reasons due to wear, such as an increasing occurrence of soiling on the drive pulley and / or the suspension elements, for example due to over-lubrication and / or the use of the wrong lubricant. The mentioned slip can easily be measured directly or indirectly. For example, a car travel path covered by the elevator car during a movement can be compared with a traction sheave travel path or a pulley travel path, ie with the distance by which the outer surface of the traction sheave or the deflection roller shifts during the travel process.

Wear on the suspension element arrangement can also lead to changes in the forces exerted by the suspension elements on their anchoring. The possible wear-related changes in the mechanical stresses in suspension elements already mentioned above can also have an effect on their anchoring. If the tension of the suspension element deviates excessively from a target value, it may be necessary to re-tension the suspension element. Otherwise, uneven suspension element tensions can lead, for example, to uneven or inhomogeneous wear phenomena within the elevator installation, for example on guide shoes of the elevator car and / or the counterweight. Unequal suspension element tensions can also lead to suspension elements jumping on the traction sheave and / or deflection pulleys and / or an inclined position of deflection pulleys on the elevator car or the counterweight. Ultimately, this in turn enables increased wear and tear on the components of the suspension element arrangement to be both brought about and verified.

The forces caused by the suspension elements on their anchorages can be determined, for example, with the help of so-called intelligent fixed points. A fixation of the suspension elements, for example on an elevator shaft ceiling, not only serves to hold the suspension elements mechanically. Instead, the fixation is also equipped with suitable technical means in order to be able to determine the forces exerted on the fixation by the suspension element. The determined forces or stresses in the fixation or the anchoring can be determined with relatively little effort with sufficient precision to be able to draw conclusions about wear conditions within the suspension element arrangement, in particular conclusions about wear conditions on various components of the suspension element arrangement.

According to one embodiment of the invention, the proposed method additionally comprises the following steps:

- Monitoring an actual time course of a second parameter which influences the wear state of at least one of the monitored components and / or correlates with the wear state of at least one of the monitored components, the second parameter being different from the first parameter;

Determination of the state of wear of the first monitored component based both on the result of comparing the actual time profile of the monitored first parameter with a predetermined expected time profile of the first parameter and on the result of monitoring the actual time profile of the monitored second parameter.

In other words, in addition to monitoring the actual time profile of the first parameter, a further, second parameter can be monitored with regard to its actual time profile. This second parameter can, for example, reproduce a physical property of one of the components of the suspension element arrangement, which, similar to the case of the first parameter, correlates with the state of wear of the relevant monitored component. Alternatively or in addition, the second parameter can influence the state of wear of the monitored component, that is to say the second parameter can reproduce a physical property that has an influence on how the wear in the relevant component changes over time. The second parameter can thus reproduce a physical property that is not necessarily a property of the relevant component itself, but rather a property of ambient conditions or boundary conditions in which the component is operated and which also influence wear and tear on the component.

The component whose state of wear is influenced by or correlates with the second parameter can be the same component as the first Component whose state of wear correlates with the first parameter monitored according to the method. However, the components can also differ.

The state of wear of the first monitored component can then be determined on the basis of the two monitored parameters, i.e. the actual time profile of the first parameter and the actual time profile of the second parameter. In other words, information about the current and / or future wear state of the first component can be based both on the actual time profile of the first parameter and a comparison of this profile with the associated predetermined expected time profile of the first parameter and based on the actual time profile Course of the second parameter can be derived.

By taking into account actual temporal progressions of two different parameters, various advantageous effects can be achieved which can have a positive effect on reliability, accuracy and / or other properties of the information determined about the state of wear of the component.

For example, according to one embodiment, the first parameter and the second parameter can correlate in different ways with the state of wear of the first monitored components.

In other words, the state of wear of the first monitored component can have different effects on the first and second parameters or can be influenced by them. Both parameters then correlate with the state of wear of the monitored component or influence it, but a manner of qualitative and / or quantitative correlation can differ between the two parameters. Thus, by measuring both parameters, a certain redundancy can be achieved for the determination of the state of wear. On the other hand, the different types of correlation with the state of wear can lead to the fact that, overall, a more precise statement can be made about the state of wear. According to a further embodiment of the method, the first parameter and the second parameter can correlate in an interacting manner with the state of wear of the first of the monitored components.

In other words, the two parameters to be monitored in the method with regard to their actual temporal course can advantageously be selected in such a way that the properties they represent interact, i.e. influence one another. In particular, the parameters can be selected in such a way that variations in the second parameter influence the wear occurring in the component monitored therewith in a way that can be recognized with the aid of the first parameter.

For example, an ambient temperature in an elevator shaft accommodating the suspension element can be measured as a second parameter. This ambient temperature generally influences the wear that occurs on the suspension element. The state of wear of the suspension element can then be determined, for example, based on a first parameter that correlates with the state of wear of the suspension element, i.e. for example a length of the suspension element to be measured or a modulus of elasticity of the suspension element, and the ambient temperature can also be taken into account.

In a further exemplary embodiment, for example, the ambient temperature and the slip behavior of a belt are correlated.

According to one embodiment, based on measurement results of the monitored second parameter, the predetermined expected time profile of the first parameter can be selected from a plurality of possible predetermined expected time profiles of the first parameter.

In other words, it can be known in advance that the physical properties reproduced by the second parameter generally influence the course over time of wear occurring in a component of the suspension element arrangement in a predetermined manner. This can be done in advance, for example, through experiments, observations on existing elevator systems, calculations or simulations have been determined. Accordingly, the expected time course of the first parameter, which correlates with this wear, can differ, depending on how the physical property reproduced by the second parameter actually occurs.

By measuring the second parameter and monitoring its actual course over time, a more precise statement or a more precise assumption can be made with regard to the expected course over time of the first parameter. Since the monitored actual time profile of the first parameter can be compared with an expected time profile of the first parameter predetermined more precisely in this way, overall more reliable and / or more accurate information about the state of wear of the monitored component can be derived.

In the embodiments described above, the second parameter to be monitored can be selected in concrete terms from the group of parameters comprising:

- a temperature in the area of the suspension arrangement,

- a humidity in the area of the suspension element arrangement, and

- an air pressure in the area of the suspension element arrangement.

In other words, as a variant of this embodiment, the second parameter to be monitored can be the temperature in the area of the suspension element arrangement, ie for example an air temperature prevailing in the elevator shaft or a temperature measured directly on one of the components of the suspension element arrangement. This temperature generally influences the wear that occurs on the suspension element arrangement over time. The wear and tear often increases as the temperature rises. In this case, it can be advantageous for the proposed method that the temperature is not measured at a single point in time and an attempt is then made to draw a conclusion about the wear from this, but instead that a time profile of the temperature is monitored. Information about this temperature profile over time or an average temperature calculated therefrom during a period enables a more precise statement to be made about wear that is typically to be assumed within this time period and thus about an expected time profile of the first parameter. By comparing the determined actual temporal course of the first parameter with the temperature-dependent expected temporal course of the first parameter, statements about the current state of wear of the monitored component can then be determined with relatively high accuracy. For example, in particular the condition of the casing of plastic-coated suspension elements that are subject to aging phenomena can be determined in this way.

It may even be possible to determine statements about a future state of wear of this component. For example, if the actual time profile matches the expected time profile within an acceptable tolerance, a time extrapolation can be used to deduce a future point in time, in addition, the wear will exceed an acceptable level. This information can be used, for example, to plan maintenance work on the elevator system in advance. This can save work and / or costs.

As an alternative or in addition, the second parameter to be monitored can be the air humidity in the area of the suspension element arrangement. The prevailing air humidity also typically has an influence on wear that occurs in a suspension element arrangement. For example, increased air humidity can lead to greater wear, for example due to corrosion phenomena. In this case too, based on the actual temporal course of the air humidity or a mean value derived therefrom, a conclusion can be drawn as to how wear will occur in the observed period and which temporal course of the first parameter is to be expected accordingly. The actual time profile of the first parameter can then be compared again with the expected time profile of the first parameter, which is predetermined based on the second parameter.

As a further possibility, the second parameter to be monitored can be the air pressure in the area of the suspension element arrangement. The air pressure prevailing during an observation period can also have an influence on the wear that occurs in the suspension element arrangement, so that the information about the actual time The course of the air pressure can in turn be used in order to be able to realistically pre-determine the expected course of the first parameter over time.

As an alternative or in addition, in the embodiments described above, the second parameter to be monitored can specify a frequency of journeys by an elevator car moved by the suspension element arrangement.

The frequency with which the elevator car is displaced with the aid of the suspension element arrangement within an observation period naturally also has an influence on the occurrence of signs of wear on the suspension element arrangement. By observing as a second parameter how often the elevator car has been moved in relation to a unit of time or within a period of time since the beginning of the observation, information can be obtained on the basis of which, in turn, an expected temporal course of the first parameter can be predetermined so that the actually observed temporal course of the first parameter can again be compared with this expected time profile in order to be able to draw conclusions about the state of wear of the monitored component.

It may also be possible to take into account how far, i.e. over what travel distance, the observed journeys were, which payload was transported during the observed journeys and / or other variables that can influence the wear and tear that occurs with the journeys. Furthermore, in addition to the monitoring of the frequency of journeys, other parameters can be monitored as second parameters, such as the temperature, air humidity and / or air pressure already explained in the area of the suspension element arrangement.

According to one embodiment, the state of wear can be determined based on a deviation of the actual time profile of the monitored first parameter from a predetermined expected linear time profile of the first parameter.

In other words, the monitored actual time profile and the predetermined expected time profile of the first parameter can be compared with one another permanently or at certain time intervals. For the predetermined In this case, a linear course can be assumed over time, ie it can be assumed that the properties of the monitored component of the suspension element arrangement, which are reproduced by the first parameter, change in a linear manner over time. A way in which the actual time profile of the monitored first parameter differs from the predetermined expected linear time profile of this first parameter can make it possible to draw conclusions about prevailing or future wear conditions.

In many cases or over longer periods of time, for example, the monitored actual time profile of the first parameter will also change linearly over time. A proportionality factor reflecting the time dependency of the changes can be the same or different for the actual time profile and the expected time profile. Depending on how the two proportionality factors differ from one another, conclusions can be drawn about a current state of wear of the monitored component.

In an alternative scenario, the monitored actual temporal course of the first parameter can initially change linearly, but then change its temporal development and no longer change linearly as a function of time but, for example, disproportionately or disproportionately. The discrepancy to be observed here between the actual time profile of the first parameter and the predetermined expected linear time profile of the first parameter can enable a conclusion to be drawn about current and / or future wear states.

According to one embodiment, the state of wear can be determined based on a reversal of a property of the actual time profile of the monitored first parameter compared to a previous time profile of the first parameter.

In other words, it can be observed that the monitored first parameter develops over a certain period of time in a certain direction, that is to say follows a trend. From a certain point in time, the direction in which the property reproduced by the first parameter changes can reverse, ie it comes to a trend reversal. If such a trend reversal is recognized by comparing the actual time profile of the first parameter with the expected time profile of the first parameter, this can contain information about the current and / or future wear state of the monitored component. In this case, the expected time profile of the first parameter can correspond to a previous time profile of the first parameter. In other words, the trend reversal can be recognized when the actual time profile of the first parameter differs significantly over time from a time extrapolation of a previous actual time profile of the first parameter.

According to one embodiment, the state of wear can be determined based on a change in sign of a second time derivative of the actual time profile of the monitored first parameter compared to a second time derivative of the previous actual time profile of the first parameter.

In other words, it can be observed how the actual time course of the monitored first parameter changes over time. The changes that occur over time can be reproduced by a first time derivative of the actual time profile of the first parameter. In doing so, they can follow a trend, i.e. they can become successively smaller, for example, so that the physical property represented by the first parameter appears to be approaching a saturation value. If such a trend changes, this can mean that the changes in the first parameter, which originally became smaller and smaller as a function of time, suddenly become larger again. This can typically be accompanied by a change in sign in the second time derivative of the actual time profile of the monitored first parameter. Such a sudden change in the previous trend and the associated change in sign can be an indication of the existence of a certain state of wear on the component in question.

According to one embodiment using a specific example, the state of wear can be based on an incipient decrease in a modulus of elasticity rope-like suspension element of the suspension element arrangement can be determined after a preceding successive increase in the modulus of elasticity of the rope-like suspension element.

In this specific example, the suspension element can be a rope with a large number of inner and outer strands. Typically, the inner strands effect a large part of the load-bearing capacity of the rope and take over a major part of the mechanical stresses within the rope during use. The outer strands surround the inner strands and protect them. Although the outer strands normally contribute to the flexural rigidity of the rope, they only take on a small part of the load-bearing capacity and thus the mechanical stresses in the rope. The rope core (inner strands) has a higher mechanical longitudinal tension than the outer strands in solid steel ropes (in the typical elevator load range between 2 and 8.33% minimum rope breaking load). The tension level of the outer strands is massively lower than that of the rope core due to the stranded structure.

Over time, the inner strands in particular may experience a gradual increase in the elasticity of the rope due to symptoms of fatigue, i.e. a decrease in the rope's modulus of elasticity. The rope is apparently becoming increasingly softer, so that readjustments when approaching floors and level adjustments when loading and unloading the elevator car increase over time.

After a certain point in time, the more frequent and stronger stretching of the rope can lead to tears or breaks in the inner strands. This means that the load-bearing capacity of the rope is no longer, as before, mainly taken over by the inner strands, but increasingly also by the outer strands. This can lead to a trend reversal in the effective modulus of elasticity of the entire rope, ie, after the modulus of elasticity of the rope has initially decreased successively, it can suddenly increase again. This trend reversal can be seen in a change in sign of the second time derivative of the actual time profile of a modulus of elasticity to be measured or of a measured variable that is correlated with it. The trend reversal can provide an indication that a certain state of wear has set in the rope or will set in the future. For example, based on the trend reversal, it can be concluded that inside the rope The strands are no longer able to cope with the mechanical stresses that are normally to be absorbed there and therefore the rope should be discarded, ie replaced, in the near future.

According to one embodiment, the predetermined expected time profile of the first parameter can be predetermined based on a large number of measured values that were determined on different elevator systems.

In other words, the actual temporal progression of the first parameter can be compared with an expected temporal progression of this parameter, which was determined in advance in that measured values were recorded on a large number of elevator systems that correspond to this first parameter or at least correlate with it. The actual temporal course of the first parameter recognized on a certain suspension element arrangement of an elevator installation can thus be compared, for example, with previously recorded actual temporal courses, as they were observed on other elevator installations. Based on such a comparison, in particular based on deviations between the actual temporal course observed on the specific elevator system and the actual temporal course of the first parameter previously observed on other elevator systems, the current or future wear conditions of the monitored component in the suspension element arrangement of the concrete Elevator system can be inferred.

According to the second aspect of the invention, a monitoring device is described which is configured to implement embodiments of the method described above.

For this purpose, the monitoring device can have one or a plurality of sensors, with the aid of which the first and / or the second and / or further parameters can be measured. For example, the monitoring device can have sensors for measuring the length of the suspension element, sensors for measuring expansion properties of the suspension element, sensors for measuring radial dimensions of the suspension element, sensors for measuring optical properties of the suspension element, sensors for measuring magnetic properties of the suspension element, sensors for measuring electrical properties of the suspension element, sensors for measuring mechanical stresses within the suspension element, sensors for measuring dimensions on a structure of the contact surface of the traction sheave, sensors for measuring any slip that occurs between the suspension element and the contact surface of the traction sheave and / or sensors for measuring forces, which are exerted on an anchorage by the suspension element. Such sensors can include, for example, optical sensors such as photodiodes or cameras, electrical sensors, mechanical sensors, magnetic sensors, etc.

The sensors can generate and forward a measurement signal, in particular an electrical measurement signal, as a function of a currently measured parameter. The monitoring device can have an evaluation device in which the measurement signals are received and evaluated. The evaluation device can have a processor with which measurement signals or measurement data can be processed. In particular, the monitoring device can have a data memory in which measurement signals can be temporarily stored. Specifically, the monitoring device can be configured to record measurement signals and ultimately to monitor the actual time course of a parameter by temporarily storing them.

The monitoring device can be connected to a control of the elevator installation in order to be able to exchange data with it. In particular, information about the state of wear determined in the monitoring device can be passed on to the control of the elevator system. As an alternative or in addition, the monitoring device of the elevator installation can be connected to a control center, for example, in order to be able to transmit the information about the determined state of wear to the control center. Furthermore, the monitoring device of the elevator system can optionally be connected to monitoring devices of other elevator systems and can exchange data with them.

The proposed according to the third aspect of the invention computer program product contains software in the form of computer-readable instructions that a computer, for example part of the monitoring device described above may be, instructs to carry out or control embodiments of the method proposed herein. The computer program product can be formulated in any computer language.

According to the fourth aspect of the invention, the computer program product can be stored on a computer-readable medium. The computer-readable medium can be implemented technically in different ways. For example, the computer-readable medium can be a flash memory, a CD, a DVD or other portable, volatile or non-volatile memory. Alternatively, the computer-readable medium can be part of a network of computers or servers, in particular part of the Internet or part of a data cloud, from which the computer program product can be downloaded.

It is pointed out that some of the possible features and advantages of the invention are described herein with reference to different embodiments on the one hand of the method described herein and on the other hand of the monitoring device implemented for its execution. A person skilled in the art recognizes that the features can be combined, transferred, adapted or exchanged in a suitable manner in order to arrive at further embodiments of the invention.

Embodiments of the invention are described below with reference to the accompanying drawing, neither the drawing nor the description being to be interpreted as restricting the invention.

1 shows a monitoring device for determining a state of wear of components of a suspension element arrangement in an elevator installation according to an embodiment of the present invention.

The figure is only schematic and not true to scale. Identical reference symbols denote identical or identically acting features 1 shows an elevator installation 1 in which a state of wear of components of a suspension element arrangement 5 can be determined with the aid of a monitoring device 3.

The elevator installation 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 with the aid of the support means arrangement 5. For this purpose, the suspension arrangement 5 has several rope-like suspension elements 15 such as ropes, belts or belts. The support means 15 can be driven with a drive pulley 17 of a drive machine 19. For this purpose, the traction sheave 17 can have a structure adapted to a geometry of the suspension means 15, for example in the form of grooves, grooves or the like, on a contact surface 21 on which the suspension elements 15 rest on the traction sheave 17. In the example shown, the support means 15 are fixed to a ceiling 25 of the elevator shaft 11 via anchors 23. From there, the support means 15 run down to pulleys 27, 29, which are attached to the cabin 7 or the counterweight 9, in order to then run up to the drive pulley 17 of the drive machine 19 again. Operation of the drive machine 19 is controlled by an elevator control 31. The elevator control 31 can communicate with the monitoring device 3.

A large number of sensors or sensor systems are provided in the elevator system 1, with the aid of which parameters can be monitored, which enable a conclusion to be drawn about states or properties within the elevator system 1 that correlate with or influence the wear states of components of the suspension element 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 reflect parameters measured by them, to the monitoring device 3.

For example, a length measuring sensor system 35 is provided at a lower end of the elevator shaft 11 in the vicinity of a buffer 33 adjoining a travel path of the counterweight 9. With the aid of this length measuring sensor system 35, a distance between the counterweight 9 and the buffer 33 can be determined when the counterweight 9 is in its lowest possible position, that is, when the car 7 is located on the highest possible floor 13. From the measurement of this distance, a current length of the suspension element 15, which can change over time, in particular due to material expansions, can be inferred indirectly.

Radial dimensions of the suspension element 15, that is to say, for example, a diameter of suspension cables or a thickness of suspension belts, can be measured with the aid of 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 onto the suspension element 15. If necessary, this camera 37 can alternatively or additionally also be used in order to be able to recognize optical properties of the suspension elements such as a change in surface textures on the suspension elements and / or a change in color, reflectivity, etc.

Furthermore, a sensor system 39 can be provided for measuring magnetic properties of the suspension elements 15. With the aid of this sensor system 39, for example, a magnetic flux through one of the suspension elements 15 can be measured.

In addition or as an alternative, a sensor system 41 for measuring electrical properties of the suspension element 15 can be provided. This sensor system 39 can, for example, measure electrical current flows or an electrical resistance through one of the suspension elements 15.

The anchorages 23 can be designed as intelligent fixed points and can be configured to measure mechanical stresses on or in the suspension elements 15. For example, strain gauges can be provided in the anchors 23, which interact with the support means 15 or their anchored ends. If necessary, the anchors 23 can also be designed to measure forces caused by the suspension means on the anchors 23.

Furthermore, a sensor system 43 can be provided, with the aid of which dimensions on 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 with the aid of a camera or others optical sensors, but sensors that act differently can also be used.

In addition, the monitoring device 3 can receive data and information from the elevator control 31 and / or from further sensors 45, with the aid of which, for example, a current position of the elevator car 7 in the elevator shaft 11 can be determined, based on which additional parameters related to the wear of components correlate the suspension element arrangement 5, can be inferred.

For example, from a way, i.e. for example how often and / or over what distance, level controls are carried out by the elevator control 31 when the elevator car 7 stops on a floor 13, conclusions can be drawn about the expansion properties of the suspension elements 15.

By comparing a controlled displacement distance, which was controlled by the drive machine 19 controlled by the elevator control 31, with an actual displacement distance of the car 7 or the counterweight 9, as can be recognized, for example, from the signals of the sensors 45, an occurring Slippage between the suspension means 15 and the contact surface 21 of the drive pulley 17 can be inferred.

Furthermore, a temperature sensor 47, an air 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 area of the suspension elements 15.

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

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 is stored and retrieved at a later point in time can be called up, and data interfaces via which the monitoring device 3 can exchange data with the various sensors and sensor systems, for example.

As part of the method, an actual course 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 state of wear of at least one of the components of the suspension element arrangement 5. The actual time profile of the first parameter monitored in this way is then compared with a predetermined expected time profile of this parameter and, based on a result of this comparison, the state of wear of the monitored component is then determined.

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

From previous experiments, simulations and / or knowledge obtained from other elevator systems, an expected course over time can be predetermined, which indicates how the length of the suspension elements typically changes over time. By comparing the actual temporal course of the length behavior of the suspension elements 15 with the expected temporal course, a statement about the current and / or a future state of wear of the suspension elements 15 can then be determined.

For example, it can be recognized that the observed suspension elements 15 elongate more rapidly over time than is known from suspension elements serving as reference and would therefore be expected. This information can be used in order to be able to draw conclusions about a progressive state of wear and / or, for example, a point in time at which the suspension means 15 will have reached a permissible wear limit. In addition to the monitoring of the first parameter, a second parameter is preferably also monitored. Similar to the first parameter, this second parameter can correlate with the state of wear of the monitored component. However, it can be preferred that the second parameter even influences the state of wear, ie a statement can be derived from it as to the way in which the state of wear changes over time.

Many different combinations of first and second parameters to be monitored are conceivable or advantageous. It can be advantageous, for example, to select the two parameters to be monitored as a function of one another. In particular, it can be advantageous to determine the way in which the first parameter is monitored or evaluated as a function of a selection of the second parameter and / or as a function of actual time courses of the second parameter.

For example, a temperature prevailing in the elevator shaft 11 or directly prevailing on the suspension elements 15 can be monitored as a second parameter, for example with the aid of the temperature sensor 47 Suspension means 15 and can also be determined on the actual course of the measured temperature. It can be used here that a temperature prevailing over a longer period of time has an influence on the wear that occurs in the suspension elements 15 and the wear can in turn manifest itself in a change in length of the suspension elements 15. In this case, on the basis of the actual course of the temperatures, an expected course of the length changes in the suspension elements 15 can be predetermined.

Here, from a plurality of possible, predetermined, expected time profiles of the changes in length, which were calculated, simulated, experimentally determined or observed on other systems for different temperatures prevailing during a monitoring period, the expected time profile of the changes in length can be used to compare with the actual profile of the changes in length , which resulted for the actual temporal course of the temperature conditions. In general, information about the current and / or future state of wear of components of the suspension element arrangement 5 can be determined, in particular based on detected deviations of the actual time profile of the monitored first parameter from a predetermined expected time profile of this parameter, which is assumed to be linear, for example. Reversals of properties of the actual time profile of the monitored parameter or a change in sign of a second time derivative of the actual profile of the monitored parameter can also provide a good indication or a good database for determining the state of wear of the monitored component.

In a special variant of the proposed method, the expected course over time of the first parameter can be predetermined based on a large number of measured values that were measured at 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 them. The server 55 can, for example, be part of a data cloud and / or be arranged in a control center which monitors a large number of elevator systems 53.

Finally, it should be pointed out that terms such as “having”, “comprising”, etc. do not exclude any other elements or steps and that terms such as “a” or “a” do not exclude a multitude. Furthermore, it should be pointed out that features or steps that have been described with reference to one of the above exemplary embodiments can also be used in combination with other features or steps of other exemplary embodiments described above. Reference signs in the claims are not to be regarded as a restriction.

Claims

1. A method for determining a state of wear of components of a suspension element arrangement (5) of an elevator installation (1), the method comprising:

- Monitoring an actual time course of a first parameter which correlates with the wear state of at least one first monitored component;

- Determination of the state of wear of the monitored component based on a result of the comparison, characterized in that the state of wear is based on an incipient decrease in the modulus of elasticity of a rope-like suspension element (15) of the suspension element arrangement (5) after a preceding successive increase in the elasticity module of the rope-like suspension element (15 ) is determined.

2. The method according to claim 1, wherein the suspension element arrangement has at least the following components:

- At least one rope-like suspension element (15),

- A drive pulley (17) driven by a drive machine (19) for displacing the suspension element (15) resting on a contact surface (21) of the drive pulley (17),

- At least one anchorage (23) of the suspension element (15) on an elevator car (7) to be displaced by the suspension element arrangement (5) and / or in an elevator shaft (11) accommodating the suspension element arrangement (5), the first parameter to be monitored being selected from the group of parameters comprising:

- a length of the suspension element (15),

- elongation properties of the suspension element (15),

- radial dimensions of the suspension element (15),

- optical properties of the suspension element (15),

- magnetic properties of the suspension element (15),

- electrical properties of the suspension element (15),

- a mechanical tension of the suspension element (15),

- Dimensions on a structure of the contact surface (21) of the traction sheave

(17), - A slip that occurs between the suspension element (15) and the contact surface (21) of the traction sheave (17), and

- A force caused by the suspension element (15) on the anchorage (23).

3. The method according to any one of the preceding claims, further comprising:

4. The method according to claim 3, wherein the first parameter and the second parameter correlate in different ways with the state of wear of the first monitored components.

5. The method according to any one of claims 3 and 4, wherein the first parameter and the second parameter correlate in an interacting manner with the state of wear of the first monitored one of the components.

6. The method according to any one of claims 3 to 5, wherein based on measurement results of the monitored second parameter, the predetermined expected time course of the first parameter is selected from a plurality of possible predetermined expected time courses of the first parameter.

7. The method according to any one of claims 3 to 6, wherein the second parameter to be monitored is selected from the group of parameters comprising:

- a temperature in the area of the suspension arrangement (5),

- A humidity in the area of the suspension element arrangement (5), and

- An air pressure in the area of the suspension element arrangement (5).

8. The method according to any one of claims 3 to 6, wherein the second parameter to be monitored indicates a frequency of journeys by an elevator car (7) moved by the suspension element arrangement (5).

9. The method according to any one of the preceding claims, wherein the state of wear is determined based on a deviation of the actual time profile of the monitored first parameter from a predetermined expected linear time profile of the first parameter.

10. The method according to any one of the preceding claims, wherein the state of wear is determined based on a reversal of a property of the actual time profile of the monitored first parameter compared to a previous time profile of the first parameter.

11. The method according to any one of the preceding claims, wherein the state of wear is determined based on a change in sign of a second time derivative of the actual time profile of the monitored first parameter compared to a second time derivative of the previous actual time profile of the first parameter.

12. The method according to any one of the preceding claims, wherein the predetermined expected time course of the first parameter is predetermined based on a plurality of measured values that were determined on different elevator systems (1).

13. Monitoring device for determining a state of wear of components of a suspension arrangement (5) of an elevator installation (1), the monitoring device (3) being configured to carry out or control the method according to one of the preceding claims.

14. Computer program product which contains computer-readable instructions which, when executed on a computer, instruct the latter to execute or control the method according to one of claims 1 to 12.

15. Computer-readable medium with a computer program product according to claim 14 stored thereon.