EP3947233B1 - Status monitoring of a load carrier - Google Patents

Description

The invention relates to a method for monitoring the physical condition of a suspension element, a device for carrying out the method and an elevator system with this device.

Elevators or elevator systems have an elevator car for accommodating people and/or objects, as well as a drive with a traction sheave and usually a suspension element. The suspension element is connected to the elevator car and guided over the traction sheave so that the drive can move the elevator car. Depending on the configuration of the elevator system, the suspension element is also connected to a counterweight. Furthermore, different suspension element guidance variants are possible. Depending on the variant of the suspension element, power transmission options are available, such as those known from cable pulls. In addition, an elevator installation can also have a plurality of suspension elements guided parallel to one another.

The most critical component of an elevator system is the suspension element. It is critical because on the one hand it carries people and on the other hand it is functionally exposed to the highest loads such as high, swelling tensile forces and bending cycles. A suspension means of the aforementioned type can be a load-bearing tension member or rope made from steel wire strands, aramid fibers or carbon fibers, which optionally has a plastic sheathing. However, it can also be an elevator belt, which is usually made of polyurethane and has load-bearing tension members made of steel wire strands, aramid fiber bundles and/or carbon fiber bundles in its interior.

Because the suspension element is guided via the traction sheave and possibly via deflection pulleys, not every length section of the suspension element is exposed to the same loads, so that the individual length sections show different signs of wear after a certain period of operation. The wear and tear that limits the service life is the reduction in the load-bearing cross-section as a result of wire or fiber breaks in the load-bearing tension members of the suspension element.

Due to these signs of wear, the suspension element has to be replaced periodically , whereby logically its most severely damaged section of length is decisive. Up to now, the number of bending cycles of the suspension element has usually been used as a measure of wear without taking into account the actual condition of the suspension element. This exchange is very expensive, which is why the operator is very interested in using the suspension element for as long as possible without risking the suspension element breaking during operation.

To meet this need, the US2003/0111298A1 monitoring of the suspension element in the elevator system. For this purpose, the suspension element is divided into segments by markings. The markings can be detected by a detection device so that a change in length of the individual segments can be measured. The changes in length of the individual segments are then compared with a limit value. As soon as one of the segments has reached the limit value, the suspension element must be replaced. By means of this monitoring, the point in time at which the suspension element is replaced, often also referred to as the discard condition, is no longer made dependent on the operating hours, but on the actual condition of the elevator suspension element.

The proposed method is based on the description of the US2003/0111298A1 However, it assumes that the change in length must always be determined for the same load, for example when traveling with an empty elevator car. Such empty runs provided for measurement purposes restrict the availability of the elevator system. In addition, the measured change in length also includes a setting of the wire strands or fiber bundles, which has no influence on the load-bearing capacity of the suspension element. The proposed solution can lead to the suspension element being replaced too early because of the harmless settling effects contained in the measurement result.

The object of the present invention is therefore to determine the discard state even more precisely from the state of the suspension element without restricting availability.

This object is achieved by a method for monitoring the physical condition of a suspension element that is connected to an elevator car and can move it. The suspension element has markings along its length, which can be detected by a detection device. The markings can be found on the Surface of the support means are applied, for example, by color printing or by thermal processes such as laser baking. In this case, the markings can be in the form of dots, horizontal lines, matrix codes, barcodes and the like. However, the markings can also be of a different nature, such as, for example, RFID tags arranged inside the suspension element and the like. Accordingly, the detection device is matched to the marking used and can be a laser scanner, an RFID reader, a camera and the like.

So that settlement effects do not have any influence on the state determination, according to the invention, instead of the pure change in length or expansion, the expansion difference of the suspension element is monitored segment by segment. The strain difference is determined by using a signal processing unit to determine a first strain at a first load and a second strain at a second load from a distance between two selected markings detected by the detection direction, and from the two strains one determines the elastic behavior of the elongation difference representing segments is calculated. In order to record the loads acting during the strain measurements, a load measuring device is available, by means of which the load acting on the suspension element between the two selected markings can be measured.

The use of the difference in elongation as a criterion for determining the discard condition is based on the knowledge that, in addition to the setting effects, an additional change in length occurs when individual wire strands or fibers are broken or subjected to wear and the load-bearing cross-section of the suspension element is reduced. This reduction leads to a change in the elastic behavior of the suspension element segment, in that it becomes more elastic or "softer". In other words, the difference in elongation of a segment that has wire strand breaks or fiber breaks changes or increases. It can be seen here that the most important criterion for determining the discard condition is used by means of the proposed method, namely the reduction of the load-bearing cross-section of the suspension element. Since the measurements to determine the difference in strain can be carried out independently of a specified load by recording the acting load, the determination of the difference in strain is possible at any time and thus during the normal operation possible.

The calculated strain difference can then be compared to a strain difference limit. If the elongation difference of a segment is equal to or greater than the elongation difference limit value, the signal processing unit preferably sends an alarm signal to a control unit of the elevator system and/or to an output unit, for example to fix the elevator system and/or to indicate that the suspension element needs to be replaced.

Alternatively or in addition, a cross-section loss of the load-bearing cross-section can be calculated from the difference in expansion and compared with a limit value for the maximum permissible cross-section loss, or a loss of load at break can be calculated from the difference in expansion and compared with a limit value for the maximum permissible loss of load at break.

If the calculated elongation difference or the calculated cross-sectional loss or the calculated breaking load loss of a segment is below the elongation difference, cross-sectional loss or breaking load loss limit value, the signal processing unit can, for example, by extrapolating older, determined elongation difference, cross-sectional loss, or breaking load loss values and the The remaining service life of the lifting gear in use can be calculated from the currently determined values. Using this remaining service life, the replacement of the suspension element can be planned in the sense of a forward-looking maintenance plan for both the operator and the maintenance company.

In order to reduce the amount of data resulting from the measurements and calculations, the strain differences of the individual segments can be compared with one another and a hierarchy of the segments can be created with regard to their strain difference. The segments can be selected analogously to this hierarchy, so that the expansion difference of segments with an already increased expansion difference is determined more frequently and compared with the expansion difference limit value than of segments with an unchanged expansion difference. Furthermore, a random algorithm can be present, according to which segments with previously unchanged or slightly changed elongation difference and their elongation differences are selected at random be determined.

Since the markings are arranged on the suspension element, they can also be subject to signs of wear. In order to continue to enable a trouble-free determination of the strain difference, there can be a detectability criterion with regard to the detectability of the markings. If a marking does not meet this detectability criterion and is therefore difficult or impossible to read, the next readable marking can be selected by the detection device or the signal processing unit.

In order to be able to assess the change in stiffness more precisely, it is advantageous not to use a standard value from the manufacturer, but instead to analyze the suspension element actually used in its new condition. For this purpose, a strain difference in the new condition of each segment can be measured and stored when the suspension element is put into operation by measuring several strains of the segment at different loads in the new condition and storing it as the force/strain curve reflecting the strain difference in the new condition. During operation, the elongation difference of the individual segments can then be compared periodically with the respective associated elongation difference of the force/elongation curve in the new state.

The cross-section loss of the load-bearing cross-section of this segment can also be calculated from the change in the expansion difference of a segment and the result can be transmitted to an output unit.

To carry out the method, a device is required, which has at least one suspension element divided into segments by means of markings, a load measuring device, a signal processing unit and a detection device for detecting the markings. The load measuring device can be configured very differently. For example, it can contain a load cell, which is arranged in the suspension element. Preferably, however, the load cell is not arranged in the suspension element, but rather is part of a suspension element end attachment point, at which one of the suspension element ends of the suspension element is attached either to the car, to the counterweight or to part of a structure, this structure logically being the Contains elevator system with the to-monitored support means.

The signal processing unit is set up to monitor the difference in stretching of the suspension element in segments by measuring, from a distance between two selected markings detected by the detection direction, a first stretching at a first measured load acting on the suspension element by the load measuring device and a second stretching at a second measured load acting on the suspension element by the load measuring device is determined and an expansion difference representing the elastic behavior is calculated from the two expansions. For this purpose, the signal processing unit has appropriate hardware with a processor and memory units as well as suitable software in which, among other things, the formulas listed in the description of the figures are also implemented.

Depending on the procedural sequences programmed in the software, a segment and accordingly two markings can be selected by the signal processing unit according to predetermined criteria. This selection can be transmitted to the detection device, which then detects the distance between the two selected markings. An optical system is preferably used here and the length of the segments is selected such that at least two markings can be detected simultaneously. To determine the elongation of a segment, the difference in detection time between the two selected markings and the speed or the speed profile of the suspension element relative to the detection device can also be recorded and calculated in order to determine the correct distance between the two markings or the elongation of the segment.

In order to be able to unambiguously localize the most serious wear points, each marking advantageously has an identifier that can be clearly distinguished from the other markings.

In order to facilitate detection, the two selected markings are preferably arranged one after the other on the suspension element and delimit the segment whose expansion difference is to be calculated.

However, it is also possible for further markings arranged on the suspension element to be present between the two selected markings which delimit the segment. If these two selected markings can no longer be detected simultaneously by the detection device, the length of the segment must be calculated from the detection time and the speed, as mentioned above.

The device described above can be a fixed, permanently present part of an elevator system. It is also conceivable, however, for the aforementioned device to be installed only temporarily in an elevator system in order to be able to more precisely estimate the imminent end of service life and to be able to better plan the upcoming replacement. Of course, an existing system can also be retrofitted with the device described.

A particularly precise monitoring can then be achieved if the elevator system comprises an updated digital double data set which contains the physical components of the elevator system in digital form as interconnected and interacting component model data sets with characterizing properties. In this case, the signal processing unit is set up to exchange data with the updated digital double data record.

The data transmitted from the signal processing unit to the updated digital double dataset can include the expansion differences of segments, which can be transferred as characterizing properties to assigned virtual segments of a suspension element of the updated digital double dataset that is mapped as a digital component model dataset. In this case, the corresponding previous characterizing properties or strain difference values of the virtual segments are replaced and the updated digital double data record is thereby updated.

Using the updated digital double data set, static and dynamic simulations can be carried out to determine the discard state or the remaining service life. Here, the updated digital double data set provides an excellent virtual simulation environment, since it contains all contains and depicts relevant characterizing properties of the physical components of the elevator system. For example, additional loads such as suspension element vibrations due to the changed stiffness can be simulated and their effects on the other components can be examined, so that, for example, the increased expansion difference of the segment or the correspondingly reduced load-bearing cross-section does not directly determine the discard point, but the changing vibration behavior of the suspension element and its effects, for example, on the ride comfort and other components of the elevator system such as the guide rails, the guide shoes of the elevator car and the like. The simulation results obtained in this way can then be evaluated in the signal processing unit using appropriately programmed logic; if necessary, an alarm signal can be generated by the signal processing unit and transmitted to a control unit of the elevator installation and/or an output unit. The output unit can have various configurations. For example, it can have display means such as loudspeakers or screens. Furthermore, the simulation results can be processed by the output unit with further data from the updated digital double data set and displayed on a screen as a three-dimensional virtual representation. Such a representation can also be dynamic, which means that in the virtual representation of the elevator system, three-dimensionally represented component model data sets can be moved analogously to the physical elevator system and behave dynamically according to their physical equivalents.

Figur 1:

schematisch eine Aufzugsanlage mit einer erfindungsgemäßen Vorrichtung, welche ein mittels Markierungen in Segmente unterteiltes Tragmittel, eine Erfassungseinrichtung zur Erfassung der Markierungen sowie eine Lastmesseinrichtung aufweist;

Figur 2A bis 2C:

in einer möglichen Ausgestaltung ein Abschnitt eines mittels Markierungen in Segmente unterteiltes Tragmittel, wobei die Figuren verschiedene Stadien desselben Abschnitts zeigen;

Figur 3:

ein Diagramm mit den der Erfindung zugrunde liegenden Kraft-Dehnungskurven, wobei die erste Kurve die Dehnungsdifferenz eines Segmentes im Neuzustand und die zweite Kurve die Dehnungsdifferenz desselben Segmentes bei Erreichen der Ablegereife repräsentiert;

Figur 4:

in dreidimensionaler, detaillierterer Ansicht die Aufzugsanlage der Figur 1 mit einer erfindungsgemäßen Vorrichtung sowie ein die physische Personentransportanlage abbildender Aktualisierter-Digitaler-Doppelgänger-Datensatz (ADDD), der in einer Datenwolke (Cloud) gespeichert ist und mit welchem die Signalverarbeitungseinheit Daten austauschen kann.

Embodiments of the invention are described below with reference to the accompanying drawings, neither the drawings nor the description being to be construed as limiting the invention. Show it:

Figure 1:

schematically shows an elevator system with a device according to the invention, which has a suspension element divided into segments by means of markings, a detection device for detecting the markings and a load measuring device;

Figure 2A to 2C:

In one possible embodiment, a section of a suspension element divided into segments by means of markings, the figures show different stages of the same section;

Figure 3:

a diagram with the force-elongation curves on which the invention is based, the first curve representing the difference in elongation of a segment when it is new and the second curve representing the difference in elongation of the same segment when it reaches the point of discard;

Figure 4:

in a three-dimensional, more detailed view of the elevator system figure 1 with a device according to the invention and an updated digital double data record (ADDD) that maps the physical passenger transport system and that is stored in a data cloud (cloud) and with which the signal processing unit can exchange data.

figure 1 shows schematically an elevator system 1, which is arranged in an elevator shaft 3 of a building 5. The elevator system 1 connects several floors 7, 9 of the building 5 in the vertical direction and is used to transport people and/or objects.

The elevator installation 1 has an elevator car 11 , a drive 13 with a traction sheave 15 and a counterweight 17 . Furthermore, a device 21 according to the invention is arranged in the elevator installation 1 , which comprises a suspension element 23 divided into segments S by means of markings 25 , a detection device 29 , a signal processing unit 31 and a load measuring device 33 .

Depending on the type of elevator installation, wire ropes, aramid ropes, carbon fiber ropes or belts with tension members are used as suspension elements 23 . Steel strands, aramid fiber bundles or carbon fiber bundles surrounded by a polyurethane cover can be arranged inside the belt as tension members.

The one in the figure 1 The markings 25 shown are arranged along the length of the support means 23 and are shown as small projections. In order not to impair driving comfort, the markings 25 are preferably not designed to protrude, but applied to the surface of the suspension element 23, for example by color printing or by thermal processes such as laser baking processes. Openings or indentations arranged transversely to the longitudinal extension in the suspension element 23 could also serve as markings. The markings 25 can be in the form of points, horizontal lines, matrix codes, barcodes and the like. However, the markings 25 can also be of a different nature, such as, for example, RFID tags arranged inside the suspension element and the like.

The detection device 29 is matched to the markings 25 used and can be a laser scanner, an RFID reader, a camera and the like, so that the markings 25 can be detected without any problems. Like in the figure 1 shown, several markings 25 can be detected simultaneously by the detection device 29 . This has the decisive advantage that at least the distance between two adjacently arranged markings 25 and thus the segment length L of the segment S defined by the detectable markings 25 can be determined directly from the recording made by the detection device 29 and not the speed of the at the detection device 29 passing suspension means 23 must be detected in order to calculate the segment length L of the segment S between the two markings 25 by means of the speed and the detection time.

The one in the figure 1 The suspension element guidance variant shown shows a suspension element 23 whose both ends are connected to the structure 5 via suspension element end connections 35 and which is guided over the traction sheave 15 and over deflection rollers 19 of the counterweight 17 and the elevator car 11 . From this it can be clearly seen which alternating bending loads the suspension element 23 is exposed to during the operation of the elevator installation 1 . In addition, the suspension element 23 is subjected to high tensile forces by the elevator car 11 and the counterweight 17 . Since the elevator car 11 and the counterweight 17 are accelerated in both vertical directions and braked again, the tractive force is additionally superimposed by a rising tractive force. The tensile force or load acting on the suspension element 23 can be measured using the load measuring device 33, which is arranged on both suspension element end connections 35 in the present exemplary embodiment.

The load measuring device 33 and the detection device 29 are with the Signal processing unit 31 via the signal lines 37, 39 shown with a dot-dash line.

As below using the Figures 2A to 2C and the figure 3 is explained in detail, the state of the suspension element 23 can be monitored with an elevator installation 1 which has a corresponding device 21 . The values calculated here for the difference in elongation, the loss of cross-section or the loss of breaking load can then be compared with a corresponding limit value. If these calculated values of a segment S are equal to or greater than the corresponding limit value, the signal processing unit 31 can send an alarm signal via a signal line 43 to a control unit 45 of the elevator installation 1 and/or wired or wirelessly to an output unit 47 in order to trigger further actions , such as fixing the elevator installation 1 and/or indicating that the suspension element 23 needs to be replaced.

The Figures 2A to 2C 12 show a possible embodiment of the same section of a suspension element 23 divided into segments S ₁ , S ₂ , S _n by means of markings 25A, 25B, 25C in different stages. Each of the markings 25A, 25B, 25C is a matrix code printed on the material of the suspension element 23, which has a clear, distinguishable identification, which is why the reference numbers of the markings 25A, 25B, 25C shown have been supplemented alphanumerically.

Like in the Figure 2A specified, the markings 25A, 25B, 25C delimit the segments S ₁ , S ₂ , S _n , the segment boundaries 41 being defined by the lower edges of the markings 25A, 25B, 25C in the present exemplary embodiment. Of course, the middle, the upper edge, a specific centering point of each marking 25A, 25B, 25C or other clearly identifiable properties of the marking 25A, 25B, 25C could also be used to define the segment boundary 41.

To facilitate detection, the two markings 25A, 25B, 25C selected to define a segment S ₁ , S ₂ , S _n are preferably arranged one after the other on the suspension element 23 and delimit the segment S ₁ , S ₂ , S _{n ,} its expansion difference Δε (please refer figure 3 ) is to be calculated. In the present example, these are the segment S ₁ with the segment length L ₁ and the segment S ₂ with the segment length L ₂ .

Logically, not only are the two segments S ₁ , S ₂ with their segment lengths L ₁ , L ₂ present, but preferably the entire suspension element 23 is divided into segments S _n with a comparable segment length L _n , as is shown in FIG figure 1 is indicated.

However, it is also possible that a marking 25A, 25B, 25C can no longer be detected by the detection device 29 due to signs of wear on the surface of the suspension element. In this case, the illegible mark 25A, 25B, 25C can be skipped and the next mark 25A, 25B, 25C selected. In the present example, the middle of the three markings 25B shown is illegible for the detection device 29, so that it is skipped and another marking 25B arranged on the suspension element 23 is present between the two selected markings 25A, 25C, which delimit the segment S ₃ . As a result, this newly defined segment S ₃ has the segment length L ₃ . If these two selected markings 25A, 25C can no longer be detected simultaneously by the detection device 29, the segment length L ₃ of the segment S ₃ must, as mentioned above, be calculated from the detection time of the two markings 25A, 25C and the speed of the suspension element 23 .

In order to be able to show different influences on the suspension element 23 better, FIG Figure 2A a section of the suspension element 23 in a brand new, unloaded state, so that the segments S ₁ , S ₂ have the segment lengths L ₁ , L ₂ created by the imprinting of the markings 25A, 25B, 25C.

The Figure 2B shows the same section as the Figure 2A likewise in new condition, but for example under the load F _N , which corresponds, for example, to the maximum permissible load or maximum permissible loading of the elevator car 11 . Here, the suspension element 23 is stretched, so that the segment S ₁ has the segment length L ₁ + ε _NS1 and the segment S ₂ has the segment length L ₂ + ε _NS2 .

The Figure 2C shows the same section as the Figure 2B under the same load F _N , but after the suspension element 23 has been used for a long time, when it has reached the end of its service life or has reached the point of discard. How compared to Figure 2B clear As can be seen, the segment length L ₁ +R+ε _ABS1 of the first segment S ₁ has increased at least by the setting effects R for the same load F _N . The settling effects R of segment S 1 alone do not lead to discard, since these are essentially caused by the irreversible alignment of the tension members under load and/or by irreversible or permanent elongations as a result of rolling effects on the deflection rollers and the load-bearing cross-section of suspension element 23 as a result is not significantly reduced.

As the indices reveal, the proportion of length of elongation at discard ε _ABS1 can also differ from the proportion of length of elongation in new condition ε _NS1 . However, this can only be determined if the pure length component of the setting effects R were known. However, this cannot be determined in isolation from the elongation.

The segment S ₂ also has setting effects R, so that it has the segment length L ₂ +R+ε _NS2AB . Because the two segments like that Figure 2A shows, originally had about the same segment lengths L ₁ , L ₂ and as the Figure 2B shows that each segment S ₁ , Sz also has a comparable strain ε _NS1 , ε _NS2 and thus a comparable strain difference ΔΣ, the segment lengths L ₁ , L ₂ in the Figure 2C also be about the same length. However, this is not the case since segment S ₂ is significantly longer than segment S ₁ . This difference is due to a reduction in the strain difference Δε in this segment S2. This change correlates directly with a reduction in the load-bearing cross section of the suspension element 23, since this reduction makes segment S2 "softer" and allows it to stretch more with the same load F _N . By determining the expansion difference Δε during the operation of the elevator system 1 for each segment S ₁ , S ₂ , S _n according to the invention, the problems relating to the setting effects R shown above can be avoided.

With regard to the reference symbols L ₁ , L ₂ , R, ε _NS1 ε _NS2AB it should be noted that these would have different units according to the usual meaning. The in the Figures 2A to 2B The selected addition is only intended to indicate the parts of the length change based on various causes.

figure 3 shows a diagram with the force-strain curves D _NEW , D _AB and D _S1 on which the invention is based. The first force-strain curve D represents _NEW the elongation difference Δε _NEW of a segment S ₁ , S ₂ , S _n when new and the second force-elongation curve D _AB the elongation difference Δε _AB of a segment S ₁ , S ₂ , S _n when the discard state is reached. The ordinate of the diagram shows the elongation Σ of a segment S ₁ , S ₂ , S _n as a percentage of the original segment length L ₁ , L ₂ , L _n and the abscissa shows that in segment S ₁ , S ₂ , S _n or on the suspension element 23 applied load F applied.

The diagram shown clearly shows that the setting effects R have no influence on the monitoring of the state of the suspension element 23 . The setting effects R are a pure offset between the two force-strain curves D _NEW , D _AB . According to the invention, instead of the pure elongation ε, the elongation difference Δε of the suspension element 23 is monitored in segments. The determination of the strain difference Δε is done in that by means of in the figure 1 shown signal processing unit 31 determines a first strain ε ₁ for a first load F1 and a second strain ε ₂ for a second load F2 from a distance or the segment length L ₁ , L ₂ , L _n between two selected markings 25 detected by the detection direction 29 and from the two strains ε ₁ , ε ₂ a strain difference Δε representing the elastic behavior is calculated according to the following general formula: $$\mathrm{strain\; differential}\Delta \mathrm{e}={\mathrm{e}}_2-{\mathrm{<figure-callout\; id="1"\; label="e"\; filenames="imgf0003.png"\; state="\{\{state\}\}">e</figure-callout>}}_1$$

• Dehnungsdifferenz im Neuzustand: Δε_NEU = ε_NEU2 - ε_NEU1
• Dehnungsdifferenz bei ablegereife: Δε_AB = ε_AB2 - ε_AB1

wobei die Formelzeichen sind:

• ε_NEU1 = Dehnung Neuzustand bei Last F₁
• ε_NEU2 = Dehnung Neuzustand bei Last F₂
• ε_AB1 = Dehnung Ablegereife bei Last F₁
• ε_AB2 = Dehnung Ablegereife bei Last F₂

The following applies to the "new condition" and "discard condition" cases shown in the diagram:

• Elongation difference in new condition: Δε _NEW = ε _NEW2 - ε _NEW1
• Elongation difference when ready for discard: Δε _AB = ε _AB2 - ε _AB1

where the symbols are:

• ε _NEW1 = elongation when new at load F ₁
• ε _NEW2 = elongation when new at load F ₂
• ε _AB1 = elongation discard at load F ₁
• ε _AB2 = elongation discard at load F ₂

wobei die Formelzeichen sind:

• F₁= erste Last
• F₂ = zweite Last, welche grösser ist als die erste Last F₁
• E = Elastizitätsmodul des tragenden Querschnitts
• Δε_NEU = Dehnungsdifferenz im Neuzustand
• Δε_AB Dehnungsdifferenz bei Ablegereife

The cross-section loss ΔA of the load-bearing cross-section of the suspension element 23 in the corresponding segment S ₁ , S ₂ , S _n can also be calculated using the determined expansion differences Δε _NEW , Δε _AB : $$\mathrm{cross\; section\; loss}\Delta \mathrm{A}=\frac{f2-f1}{E\ast \Delta \mathrm{e}\mathit{NEW}}-\frac{f2-f1}{E\ast \Delta \mathrm{\epsilon }\mathrm{AWAY}}$$

where the symbols are:

• F ₁ = first load
• F ₂ = second load, which is greater than the first load F ₁
• E = Young's modulus of the supporting section
• Δε _NEW = elongation difference in new condition
• Δε _AB Elongation difference at discard point

wobei die Formelzeichen sind:

• F_{Bruch NEU} = Bruchlast des Tragmittels im Neuzustand
• A_NEU = Querschnittfläche des tragenden Querschnitts des Tragmittels im Neuzustand
• ΔA = Querschnittverlust

The breaking load loss in this segment S ₁ , S ₂ , S _n can also be calculated: $$\mathrm{breaking\; load\; loss}\Delta {\mathrm{f}}_{\mathrm{fracture}}=\frac{\mathit{ANEW}-\mathit{\Delta A}}{\mathit{ANEW}}\ast {\mathrm{f}}_{\mathrm{fracture}\mathrm{NEW}}$$

where the symbols are:

• F _{Fracture NEW} = breaking load of the suspension element when new
• A _NEW = Cross-sectional area of the load-bearing cross-section of the suspension element when new
• ΔA = loss of area

From the above explanations it can be seen that the cross-sectional loss ΔA or breaking load loss ΔF _break can be compared with defined limit values for the maximum permissible cross-sectional loss ΔA _limit or the maximum permissible breaking load loss ΔF break _limit . When these limit values are reached, discard maturity is reached.

In figure 3 is also shown with a dot-dash line the example of a force-strain curve D _S1 , which shows the difference in strain Δε _S1 of the segment S ₁ after several hours of operation. The setting effects R _S1 , which have not yet progressed that far, can also be seen for this specific segment S ₁ . Like the parallel progression of the force-strain curve D _S1 of the segment S ₁ already loaded by the operation Force-elongation curve in the new condition D _NEW can be clearly seen, the difference in elongation Δε _S1 of the segment S ₁ does not differ from the difference in elongation in the new condition Δε _NEW despite the number of hours of operation, and the suspension element 23 is therefore not yet discardable in relation to this segment S ₁ reached. Even if the setting effects R _S1 of segment S ₁ were equal to the setting effects R, the suspension element 23 would not yet be ready for discard in relation to this segment S ₁ due to the lack of difference in the expansion differences Δε _S1 , Δε _NEW .

The use of the expansion difference Δε as a criterion for determining the discard condition is based on the knowledge that, in addition to the setting effects R, an additional change in length occurs if individual wire strands or fibers of the load-bearing cross-section of a suspension element 23 are broken and the load-bearing cross-section of the suspension element 23 is reduced as a result . This reduction leads to a changed elastic behavior of the segment S ₁ , S ₂ , S _n , which has been weakened by fractures and wear and tear, in that it becomes more extensible or «softer». In other words, the difference in elongation Δε of a segment S ₁ , S ₂ , S _n that has wire strand breaks or fiber breaks changes or increases. It can be seen that the proposed method uses the most important criterion for determining the discard condition, namely the reduction of the load-bearing cross-section of the suspension element 23. Since the measurements for determining the strain difference Δε are independent of the detection of the acting load F ₁ , F ₂ a fixed load F ₁ , F ₂ can take place, the determination of the expansion difference Δε is possible at any time and thus during normal operation of the elevator installation 1 . The two loads F ₁ , F z should logically be different and the measurements should preferably be carried out with the elevator car 11 traveling in the same direction. In order to record the loads F ₁ , F ₂ acting on the suspension element 23 between the two selected markings 25 during the strain measurements, the figure 1 illustrated load measuring device 33 is provided.

If the calculated elongation difference Δε of a segment S ₁ , S ₂ , S _n is below the elongation difference limit value Δε _limit , the remaining service life of the suspension element 23 in use can be calculated in the signal processing unit 31, for example by extrapolating older, determined elongation difference values Δε and the most recent elongation difference values Δε be calculated. Using this remaining service life, plan the replacement of the suspension element 23 in the sense of a forward-looking maintenance plan both for the operator and for the maintenance company.

In order to be able to assess the change in the difference in elongation Δε more precisely, it is advantageous if the suspension element 23 actually used is analyzed in its new state rather than resorting to a standard value from the manufacturer. For this purpose, a strain difference in the new condition Δε _NEW of each segment S ₁ , S ₂ , S _n can be measured and stored when the suspension element 23 is put into operation by measuring several strains of the segment S ₁ , S ₂ , S _n in the new condition at different loads F ₁ , F ₂ is measured and stored as the force/strain curve representing the strain difference in the new state Δε _NEW . During operation, the expansion difference of the individual segments S ₁ , S ₂ , S _n can then be compared periodically with the respective associated expansion difference in the new state Δε _NEW .

figure 4 shows the elevator system 1 in more detail in a three-dimensional view figure 1 with a device 21 according to the invention. In contrast to the one shown very schematically figure 1 , are in the elevator system 1 of figure 4 there are clearly three support means 23A, 23B, 23C arranged parallel to one another, which belong to the device 21. Due to different setting effects, dynamic load differences, friction and the like, not all three suspension elements 23A, 23B, 23C are loaded equally, that is, they are subjected to the same load. In order to take this into account and the strain differences Δε of the segments S ₁ , S ₂ , S _n (see Figures 2A to 2C ) of each individual suspension element 23A, 23B, 23C as precisely as possible, each of the three suspension elements 23A, 23B, 23C is assigned a load measuring device 33A, 33B, 33C, which also belongs to the device 21. The detection device 29 provided for the device 21 can detect the markings (not shown) of all three suspension elements 23A, 23B, 23C.

A particularly precise monitoring of the state of the suspension element can be achieved if the elevator system 1 includes an updated digital double data set 101 that contains the physical components of the elevator system 1 in digital form as interconnected and interacting component model data sets with characterizing properties. Here, the signal processing unit 31 of the device 21, as represented by the double arrow 161, is set up to to exchange data 131 with the updated digital double record 101 . The updated digital double data record 101 that maps the elevator installation 1 is referred to below as ADDD 101 for better legibility.

The ADDD 101 is a virtual image that is as comprehensive as possible and tracks the current physical state of the elevator system 1 and therefore represents a virtual elevator system assigned to the elevator system 1. This means that the ADDD 101 is not just a virtual shell model of the elevator system 1, which is approximately its dimensions, but each individual physical component from the elevator car 11, the shaft doors 49, the counterweight 17 to the last screw with as many characterizing properties of these components as possible is also in digitized form in the ADDD 101 as a component model data set of the elevator car 111, as a component model data set of the shaft doors 149, as a component model data set of the counterweight 117, etc. and are shown. Likewise, interfaces of the elevator system 1 such as the elevator shaft 3 belonging to the structure 5 can be mapped as a component model data record 103 in the ADDD 101 .

The characterizing properties of their physical counterparts of the elevator system 1 contained in the component model data sets 111, 149, 117 can be geometric dimensions of the components such as a length, a width, a height, a cross section, radii, roundings, etc. The surface properties of the components such as roughness, textures, coatings, colors, reflectivities, etc. are also part of the characterizing properties. Furthermore, material values such as the modulus of elasticity, the reverse bending strength value, the hardness, the notched impact strength value, the tensile strength value, etc. can also be stored as characterizing properties of the respective component. These are not theoretical properties (target data), such as can be found on a production drawing, but characterizing properties actually determined on the physical component (actual data). Information relevant to assembly, such as the tightening torque actually applied to a screw and thus its pretensioning force, is preferably assigned to the respective component.

With each determination of strain differences Δε _S1 , Δε _S2 , Δε _Sn of the individual segments S ₁ , S ₂ , S _n these can be transmitted from the signal processing unit 31 to the ADDD 101 . The newly determined expansion differences Δε _S1 , Δε _S2 , ΔΣsn of the individual suspension elements 23A, 23B, 23C replace the previously existing expansion differences Δε _S1 , Δε _S2 , Δε _Sn of the component model data records, which are also divided into segments S ₁ , S ₂ , S _n of the support means 123A, 123B, 123C in order to update the ADDD 101 continuously.

In other words, the data 131 transmitted from the signal processing unit 31 to the ADDD 101 can include the strain differences Δε _S1 , ΔΣ _S2 , Δε _Sn of segments S ₁ , S ₂ , S _n , which as characterizing properties refer to associated virtual segments S ₁ , S ₂ , S _n of a support means 123A, 123B, 123C of ADDD 101 mapped as a digital component model data record. Logically, the measured lengths L ₁ , L ₂ , Ln of the segments S ₁ , S ₂ , S _n can also be transmitted, so that the component model data records of the suspension elements 123A, 123B, 123C also have the effective lengths of their physical counterparts.

The ADDD 101 is not tied to a specific storage location or processing location. It can be stored, for example, in the signal processing unit 31 of the device, but also in the control unit 45, in a computer 121 or in a network with a number of computer systems. In particular, as shown, ADDD 101 can be implemented in a computer network that stores and processes data in the form of a data cloud 50 (cloud). For this purpose, the computer network can have a memory, or as shown symbolically, memory resources 151 in the data cloud 50, in which the data of the ADDD 101 (symbolically shown with broken lines as a three-dimensional image of the physical passenger transport system 1) can be stored, for example electronically or magnetic form. This means that the ADDD 101 can be stored in any memory location.

The ADDD 101 can be used to carry out static and dynamic simulations to determine the discard period or remaining service life t _AB . The ADDD 101 provides an excellent virtual simulation platform, as it contains and maps all relevant characterizing properties of the physical components. The simulations can, for example, in the data cloud 50, but also by temporary The ADDD 101 is stored and processed in the signal processing unit 31 . In this way, additional loads such as suspension element vibrations due to the changed expansion differences Δε _S1 , Δε _S2 , Δε _Sn and/or due to the changed length of the suspension element 23A, 23B, 23C can be simulated and their effects on the other components examined, so that, for example, the increased expansion difference is not immediately apparent Δε _S1 , Δε _S2 , Δε _Sn of segment S ₁ , S ₂ , S _n or the correspondingly reduced load-bearing cross-section determines the discard condition, but the changing vibration behavior of the suspension element 23A, 23B, 23C and its effects, for example on the ride comfort and the components of the elevator installation 1 such as the guide rails 55, the guide shoes of the elevator car 11 and the like. Simulated interpolation using previously determined expansion differences Δε _S1 , Δε _S2 , Δε _Sn which were stored chronologically allows the time remaining until discard, also referred to as remaining service life t _AB , to be calculated.

The simulation results 159 obtained in this way can then be transmitted to an output unit, in the present example the screen 122 of a portable computer 121, as shown by the arrow 163. Furthermore, alarm signals 155 can also be generated and transmitted to the output unit 122, in particular, of course, when the calculations and/or simulations have shown that the suspension element 23A, 23B, 23C has reached its discard state. In this case, the output unit does not necessarily have to be a screen 122, but can also be a loudspeaker and the like, for example. The alarm signal 155 can, for example, also be forwarded to the control unit 45 of the physical elevator installation 1 and the like and processed there, triggering corresponding actions.

Furthermore, as symbolically represented by the arrow 157 , the simulation results can be processed with further data from the ADDD 101 and represented as a three-dimensional virtual representation 128 on the screen 122 . Such a virtual representation 128 can also be dynamic, which means that in the virtual representation 128 of the elevator system, all three-dimensionally represented component model data sets 111, 117, 149, which are provided with degrees of freedom, move through the data of the ADDD 101 as in the physical elevator system 1 and behave dynamically according to their physical equivalents.

Although the Figures 1 to 4 relate to different aspects of the present invention and these have been described in detail using the example of an elevator system 1 with a so-called 2:1 suspension element guidance variant, it is obvious that the method steps described and a corresponding device can also be used for elevator systems 1 with other suspension element guidance variants such as 1: 1, 3 :1, etc. apply. In addition, the signal processing unit 31 in the figures 1 and 4 presented as a self-contained unit of hardware and software. However, the signal processing unit 31 can also be implemented separately from the physical elevator installation 1 , for example on the portable computer 121 or in the data cloud 50 .

Finally, it should be noted that terms such as "comprising," "comprising," etc. do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality. 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. Any reference signs in the claims should not be construed as limiting.

Claims (14)

1. Method for monitoring the physical state of a suspension means (23, 23A, 23B, 23C) which is connected to an elevator car (11) and can move the same, the suspension means (23, 23A, 23B, 23C) comprising markings (25, 25A, 25B, 25C) along its length which divide the suspension means (23, 23A, 23B, 23C) into segments (S₁, S₂, S_n) and which markings (25, 25A, 25B, 25C) can be detected by means of a detection device (29), characterized in that a strain difference (Δε) of the suspension means (23, 23A, 23B, 23C) is monitored segment by segment, by a first strain (ε₁) at a first load (F₁) and a second strain (ε₂) at a second load (F₂) being determined by means of a signal processing unit (31) from a distance between two selected markings (25, 25A, 25B, 25C) detected by the detection device (29) and a strain difference (Δε) representing the elastic behavior of the segment (S₁, S₂, S_n) being calculated from the two strains (ε₁, ε₂), wherein the load (F₁, F₂) acting on the suspension means (23, 23A, 23B, 23C) between the two selected markings (25, 25A, 25B, 25C) can be measured by means of a load measuring device (33, 33A, 33B, 33C).
2. Method according to claim 1, wherein the calculated strain difference (Δε) is compared with a strain difference limit value (Δε_Grenz), or a cross-sectional loss (ΔA) is calculated from the strain difference (Δε) and this is compared with a limit value for the maximum permissible cross-sectional loss (ΔA_Grenz) or a breaking load loss (ΔF_Bruch) is calculated from the strain difference (Δε) and this is compared with a limit value for the maximum permissible breaking load loss (ΔF_{Bruch Grenz}).
3. Method according to claim 2, wherein the strain difference (Δε) of the individual segments (S₁, S₂, S_n) are compared with one another, a hierarchy of the segments (S₁, S₂, S_n) is created with regard to the strain difference (Δε) thereof and the segments (S₁, S₂, S_n) are selected analogously to this hierarchy, such that the strain difference (Δε) of segments (S₁, S₂, S_n) having an already increased strain difference (Δε) are determined more frequently than that of segments (S₁, S₂, S_n) having an unchanged strain difference (Δε).
4. Method according to any of claims 1 to 3, wherein a detectability criterion with regard to the detectability of the markings (25, 25A, 25B, 25C) is present and if a marking (25, 25A, 25B, 25C) does not meet this detectability criterion and is therefore not readable or difficult to read, the next readable marking (25, 25A, 25B, 25C) is selected.
5. Method according to any of claims 1 to 4, wherein when the suspension means (23, 23A, 23B, 23C) is put into operation, a strain difference in the new state (Δε_NEU) of each segment (S₁, S₂, S_n) is measured and stored, and during operation, the strain difference (Δε) of the individual segments (S₁, S₂, S_n) is periodically compared with the respectively assigned strain difference in the new state (Δε_NEU).
6. Apparatus (21) for carrying out the method according to any of claims 1 to 5, the apparatus (21) having at least one suspension means (23, 23A, 23B, 23C) divided into segments (S₁, S₂, S_n) by means of markings (25, 25A, 25B, 25C), a load measuring device (33, 33A, 33B, 33C), a signal processing unit (31) and a detection device (29) for detecting the markings (25, 25A, 25B, 25C), characterized in that the signal processing unit (31) is designed to monitor the strain difference (Δε) of the suspension means (23, 23A, 23B, 23C) segment by segment, by said signal processing unit determining a first strain (ε₁) at a first measured load (F₁), acting on the suspension means (23, 23A, 23B, 23C) from the load measuring device (33, 33A, 33B, 33C), and a second strain (ε₂) at a second measured load (Fz), acting on the suspension means (23, 23A, 23B, 23C) from the load measuring device (33, 33A, 33B, 33C), from a distance between two selected markings (25, 25A, 25B, 25C) detected by the detection device (29) and a strain difference (Δε) representing the elastic behavior of the segment (S₁, S₂, S_n) being calculated from the two strains (ε₁, ε₂).
7. Apparatus (21) according to claim 6, wherein a segment (S₁, S₂, S_n) and correspondingly two markings (25, 25A, 25B, 25C) can be selected according to predetermined criteria by the signal processing unit (31) and the selection can be transmitted to the detection device (29).
8. Apparatus (21) according to either claim 6 or claim 7, wherein each marking (25, 25A, 25B, 25C) has an identification which is clearly distinguishable from the other markings (25, 25A, 25B, 25C).
9. Apparatus (21) according to any of claims 6 to 8, wherein the two selected markings (25, 25A, 25B, 25C) are arranged successively on the suspension means (23, 23A, 23B, 23C) and delimit the segment (S₁, S₂, S_n), of which the strain difference (Δε) is to be calculated.
10. Apparatus (21) according to any of claims 6 to 8, wherein the two selected markings (25, 25A, 25B, 25C) delimit the segment (S₁, S₂, S_n), of which the strain difference (Δε) is to be calculated and wherein further markings (25, 25A, 25B, 25C) arranged on the suspension means (23, 23A, 23B, 23C) are present between the two selected markings (25, 25A, 25B, 25C).
11. Elevator system (1) comprising an apparatus (21) according to any of claims 7 to 10.
12. Elevator system (1) according to claim 11, wherein it comprises an updated digital twin data record (101) which contains the physical components (11, 17, 49) of the elevator installation (1) in digital form as component model data records (111, 117, 149) having characterizing properties, wherein the signal processing unit (31) is configured to exchange data with the updated digital twin data record (101).
13. Elevator system (1) according to claim 12, wherein the data transmitted by the signal processing unit (31) include the strain differences (Δε) of segments (S₁, S₂, S_n) which, as characterizing properties, can be transferred to assigned virtual segments of a suspension means (123, 123A, 123B, 123C) of the updated digital twin data record (101) depicted as a digital component model data record and replace the corresponding, previous characterizing properties of the segments (S₁, S₂, S_n).
14. Elevator system (1) according to claim 13, wherein the updated digital twin data record (101) can carry out static and dynamic simulations for determining the point of discard or remaining service life (t_AB) and the simulation results can be transmitted to a control unit (45) of the elevator system (1) and/or to an output unit (122).

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