EP3628631B1 - Method for detecting state of carriers - Google Patents

Description

The invention relates to a method for detecting the state of wear of suspension elements made of elastomeric material within a suspension or elevator system, which has a car or a suspension device which is connected to a suspension element running over deflection or drive rollers with a counterweight, the suspension elements being in have tension members or reinforcement elements embedded in their longitudinal direction in the belt body, preferably designed as twisted or laid cords, with selected physical properties of the suspension element being determined and stored as initial values after a run-in phase of the suspension or elevator system, and subsequently corresponding physical properties periodically or permanently during operation Properties of the suspension means as current values in relation to the initial values and given a warning signal or to the Au if predetermined threshold values for the differences between initial values and current values are exceeded replacement of the load-bearing equipment is requested. The invention also relates to a device for carrying out the method.

In the case of passenger and freight elevators in particular, the suspension elements in the cabins, usually steel cables, are subject to strict regulations with regard to their operational safety and tensile strength. The tensile strength can be reduced over the course of the service life of an elevator due to settlement, material wear or signs of fatigue within the suspension element. Appropriate regulations are specified for this in testing standards. Elevator systems are carefully checked by the relevant testing organizations for compliance with these regulations and statutory provisions.

As soon as a suspension element no longer meets the legal requirements, it must be exchanged, i.e. discarded, which means that it is removed from the elevator system and replaced with a new suspension element. This point in time is the so-called "discard maturity". The suspension means discussed here are those that are made of elastomeric material and have embedded tension members or reinforcement elements, ie, for example, carrying straps or carrying straps shaped in a special way.

The reaching of the discard state with the steel cables still frequently used in the prior art for elevators is determined, among other things, by a visual check. In the case of steel cables, for example, the state of the tensile strength can be assessed by visually checking the individual strands for breaks or by measuring the diameter of a steel cable that is changing. Such methods are included in the standardization and therefore belong to the state of the art.

In the case of the elevator belts or carrying belts, which are used more and more as suspension devices today and in which steel ropes or steel cords are embedded in a polymer or rubber matrix as tension members, such a check using purely optical methods is hardly possible, so that additional, more refined measuring methods are required.

A combination of optical and metrological or statistical methods is used here. As a rule, the optical integrity of the suspension means must first be checked and ensured. The strength of metallic tensile elements inside the plastic or rubber matrix can, for. B. done by resistance measurement. For this purpose, the individual tension members are electrically connected to one another. A change in the cross-section of the tension members as a result of friction (fretting) or broken strands, for example, change the resistance in the electrical conductor, which can be used as an indicator of the discard condition.

the U.S. 2004/0046540 A1 discloses a method in which wear of a rope or a rope/suspension means containing elevator belt with a plurality of ferromagnetic strands or cords can be checked in that the Changes in the magnetic field strength or changes in the magnetic flux can be detected. However, such a check during operation has the disadvantage that relatively complicated devices and apparatus have to be used for magnetization or for determining the change in field strength.

the EP 0 845 672 A1 also discloses a magnetic testing method during operation, which allows testing of the magnetic properties of a magnetizable elongated object, such as an elevator belt, with Hall sensors determining any changes in the diameter of the tension members based on the changes in the magnetic properties. This device also requires a relatively high structural and sensitive equipment effort.

In both disclosures, the application is also limited to suspension means with ropes/cords made of magnetizable or electromagnetically influenceable materials as tension members.

the JP 2001192183 A discloses an elevator provided with means capable of detecting deterioration of a suspension rope. The elevator provided with a plurality of parallel suspension ropes is provided with a means for detecting the position of a car and a counterweight in a shaft, which determines using another means for calculating an increase in the amount of elongation of each synthetic fiber rope.

The object of the invention was therefore to provide a method with which a reliable determination of the state of wear of tension or suspension belts in the form of suspension elements reinforced with tension members, in particular of elevator belts, is possible and which only requires relatively little equipment/construction effort for the associated devices included.

This problem is solved by the features of the main claim. Further advantageous developments are disclosed in the dependent claims.

First of all, the length and the elastic expansion of the suspension element during a defined lifting process during operation are determined and stored as initial values. The current values of the length of the suspension element and the elastic expansion of the suspension element are then periodically or permanently related to the initial values, with the positions of both the car and the counterweight within the elevator system or in the elevator shaft being determined via position measuring devices and, from this, both the initial Length L _start and the current length L _current of the suspension element and the different initial travel distances S _K of the car and the counterweight SG resulting from elastic stretching of the suspension element can be determined.

The differences are the change in length of the suspension element ΔL = L _start - L _current , so to speak as permanent elongation, and the change in the initial ratio of the travel distances of the car and counterweight _SK-start / S _G-start in relation to the current ratio of the travel distances from Cabin and counterweight S _K-aktuell / S _G-aktuell calculated or determined as a measure for the change in elastic expansion.

If the specified threshold values for the differences determined and calculated in this way are exceeded, a warning signal is given or a request is made to replace the carrying strap.

The term "run-in new condition" means that condition of the suspension or elevator system and the traction device/pulling belt that has arisen after a series of several hundred load cycles due to settlement and running-in of the system. A one-off upward or downward stroke is to be understood here as a load cycle. With regard to the tension belt, i.e. the suspension element, the connection between the strength members or tension members and the polymer or rubber matrix and the entry into the deflection and drive rollers has taken place to such an extent that significant changes in condition only develop after much longer periods of time.

Here, on the one hand, the change in length of the suspension means serves as an indicator of aging or the reduction in load-bearing capacity or tensile strength and reaching the point of discard. In contrast to measuring electrical resistance or measuring magnetic properties, this method can be used to determine the position of the discarded area. In addition, no time-consuming "magnetization" or tension in the suspension element is required.

A precautionary, fixed and limited use of the suspension means is no longer necessary, since the state of wear and tear, i.e. the discard state, can be determined permanently or as required.

As a result of the respective load spectrum of a suspension element, signs of wear occur in the suspension element and in the reinforcements/tension members over the course of its service life. If you look at the interaction between the tensile stress on the suspension element and the number of bends on the deflection rollers and drive pulleys, a typical wear pattern emerges, which reduces the tensile strength of the suspension element to such an extent that the discard point is reached. This reduction in tensile strength is essentially due to a reduction in the load-bearing cross-section as a result of friction/wearing of the individual filaments relative to one another, so-called "fretting". A reduction in the load-bearing cross-section can also result from brittle fractures of individual filaments as a result of the continuous bending stress.

As a result of these processes and a geometric change in the individual tension elements within the polymer matrix, there is a change in the length of the tension means. The geometric change in the individual tension members/tension elements is caused, for example, by the friction/wear of the filaments that are laid/twisted together, i.e. by the movement of the individual filaments relative to one another during operation, i.e. by the fretting already mentioned, a change in shape and the position of the individual filaments and strands of a tension member. This creates a change in diameter within the tension members and thus also an elongation of the suspension element or pull strap that can be detected. The change in length is therefore a measure of the change in the tensile strain behavior of the suspension element, ie for the aging of the suspension element. With the corresponding correlation between the elongation of the suspension element or tension belt on the one hand and the aging or remaining load-bearing capacity of the suspension element on the other hand, the method according to the invention achieves a reliable and unambiguous control of the load-bearing capacity of the suspension element and the discard time / discard maturity can be determined with sufficient accuracy.

Of course, a specific number of load cycles or a specific operating time can also be specified, after which the ratio of the originally measured length and the then existing corresponding length of the suspension element is measured.

Another indicator of the discard state, which is also determined using the method according to the invention, is the change in the initial ratio of the travel distances of car S _K and counterweight SG over time, ie the time-dependent change in S _K /SG. The relationship between the travel distances/lifting distances S _K-start / S _G-start that initially develops is considered and assessed in relation to the current ratio of the travel distances of the car and counterweight S _K-aktuell / S _G-aktuell during operation.

Cabin and counterweight are moved by the same suspension element, which is guided between these two elements via several deflection rollers / drive rollers. Cabin and counterweight thus “hang” from one end of the same suspension element or elevator belt/elevator belt. The elastic stretching of the suspension means that the travel distances, ie the lifting or lowering movements of the cabin and counterweight are slightly different during lifting processes. The ratio of these two travel distances can therefore serve as a measure of the elastic stretching of the suspension element, especially when accelerating from the idle state, such as when starting off.

As already explained above, as a result of the respective load spectrum of a suspension element, wear and tear occurs in the suspension element and in the tension members over the course of its service life, which has an influence on the shape and tensile strength of the suspension element and e.g. a reduction in the load-bearing cross-sections as a result of friction / wear of the individual filaments can cause each other. As a result of such changes in shape and strength, ie also as a result of permanent stretching and constriction of the reinforcement members of a suspension element, its elastic behavior also changes, namely the elastic stretching during operation.

This also changes the ratio of the travel distances of the cabin and counterweight S _K / SG in the course of operation. This change can be determined using the method according to the invention and can be assessed using specified values/threshold values. When a certain threshold value is exceeded, the discard state is reached.

An advantageous further development consists in the fact that the initial and the current values of the lengths and the elastic elongation of the suspension element are determined and calculated for a given, defined, identical state of the suspension or elevator system. With such an embodiment of the method, one obtains a very good comparability of the position measurements and a high level of information accuracy about the differences.

The same applies to a further advantageous embodiment of the method, which consists in determining and calculating the initial and current values of the elastic expansion of the suspension element during a defined lifting process of the suspension or elevator system, i.e. for example during an empty trip from the ground floor to the 2nd Floor.

A further advantageous embodiment is that the positions of both the car and the counterweight are recorded and stored temporarily or permanently. With such a procedure, over time, very exact load spectra are created, which result in the further operation of the elevator system extraordinarily accurate predictions about the discard maturity.

A further advantageous embodiment of the method is that a percentage frequency of certain identical or similar lifting processes is determined and correlated with the differences determined and/or predetermined threshold values.

• Abwarten der Einlaufphase,
• Sicherstellen eines gleichbleibenden definierten Zustandes (z.B. Kabine leer in Etage 1),
• Ermittlung der Position der Kabine und des Gegengewichtes mithilfe der Positionsmesseinrichtungen,
• Berechnung der Gesamtlänge des Tragriemens bzw. Tragmittels,
• Speichern der Gesamtlänge des Tragmittels als Basiswert,
• Aufzeichnung der einzelnen Fahrten der Aufzugskabine,
• Dauerhafte Ermittlung des theoretischen Belastungsgrades der Tragmittelabschnitte
• Messung der prozentualen Belastung anhand der Häufigkeit der angefahrenen Etagen (z. B. : 1.Etage zur 2.Etage → 30%; 2.Etage zur 3.Etage → 20%; 3.Etage zur 4.Etage → 20% )
• Wiederherstellung des Zustandes zum Zeitpunkt der Aufzeichnung des Basiswertes (z. B. Kabine leer in Etage 1)
• Ermittlung der Position der Kabine und des Gegengewichtes
• Erneute Berechnung der Gesamtlange des Tragmittels
• Errechnung der Gesamtlängung des Tragmittels (ΔL = L_Anfang - L_Aktuell)
• Kalkulation der Lägenänderung bezogen auf bestimmte Bereiche (welcher Tragmittelbereich steuert welche Längendifferenz bei), wobei die Ablegereife in den Bereichen zuerst erreicht wird, die am häufigsten frequentiert wird.

With such an embodiment of the method, the following sequence, for example, makes sense with regard to determining the change in length of the suspension element:

• waiting for the running-in phase,
• Ensuring a constant defined state (e.g. empty cabin on floor 1),
• Determining the position of the cabin and the counterweight using the position measuring devices,
• Calculation of the total length of the carrying strap or carrying means,
• Saving the total length of the suspension element as a base value,
• Recording of the individual journeys of the elevator car,
• Permanent determination of the theoretical degree of loading of the suspension element sections
• Measurement of the percentage load based on the frequency of the floors approached (e.g.: 1st floor to 2nd floor → 30%; 2nd floor to 3rd floor → 20%; 3rd floor to 4th floor → 20% )
• Restoration of the status at the time the base value was recorded (e.g. empty cabin on floor 1)
• Determination of the position of the cabin and the counterweight
• Recalculation of the total length of the suspension element
• Calculation of the total elongation of the suspension element (ΔL = L _start - L _current )
• Calculation of the change in length in relation to certain areas (which suspension element area contributes which length difference), whereby the discard state is reached first in the areas that are most frequently used.

After that, the maximum change in length in the corresponding areas is compared with a determined and stored limit value and a decision is made as to whether it is time to discard.

An elevator system is particularly suitable for carrying out the method, with a car or support device which is connected to a support means running over deflection or drive rollers with a counterweight, the support means having reinforcement elements or strength members embedded in the support means body in its longitudinal direction, the elevator system has at least one separate position measuring device for the positions of the cabin and/or counterweight.

A further advantageous embodiment of the elevator system is that it has at least one separate position measuring device, for example within an elevator shaft, preferably in the form of measuring cables or measuring belts guided over deflection rollers, with an incremental encoder being provided in at least one of the deflection rollers of the position measuring device and Cabin and/or counterweight are articulated on the measuring ropes or measuring belts via drivers. These so-called "shaft copyings" are extremely precise and can be used to determine changes in length or expansion of < 1 cm over the entire length of the rope.

A further advantageous embodiment of the elevator system is that a separate position measuring device is provided for the positions of either the car or the counterweight, with an incremental rotary encoder in one of the Deflection rollers of the support means is provided. This simplifies the design of the elevator system, since no "duplicate" separate position measuring devices for the car and counterweight are required.

Of course, other suitable position measuring systems can also be used, in which an encoded magnetic tape is mounted in an elevator shaft and on the Cabin or sensor attached to the counterweight along which the magnetic tape is guided.

Fig. 1

in prinzipieller Darstellung ein hier angesprochenes Tragmittel,

Fig. 2

die geometrische Veränderung eines Zugträgers aus getwisteten/geschlagenen metallischen Filamenten innerhalb des Zugriemens nach Fig. 1,

Fig. 3

schematisch eine vorteilhafte Ausbildung eines zur Durchführung des erfindungsgemäßen Verfahrens geeigneten Aufzugsystems.

The invention will be explained in more detail using an exemplary embodiment. Show it

1

in a basic representation of a suspension means mentioned here,

2

the geometric change of a tension member made of twisted/laid metallic filaments within the tension belt 1 ,

3

schematically shows an advantageous embodiment of an elevator system suitable for carrying out the method according to the invention.

1 shows a basic representation of a suspension element 1 which is provided with tension members or reinforcement members 2 running in the longitudinal direction. Each of these reinforcements consists of beaten filaments 20, such as metal, as detailed in the figure 2 are shown.

2 shows the geometric change of a reinforcement 2 made of twisted/laid metallic filaments 20 within a suspension element over time. The geometric change in the individual reinforcements arises, for example, from the fact that friction/wear of the filaments 20 that are beaten/twisted together, as shown in the left-hand part of FIG figure 2 are shown in their original position, can be changed in their shape and position by the movement of the individual filaments relative to one another during operation and the resulting "fretting".

The change in the shape and position of the individual filaments and strands of a reinforcement could then be about as they are in the right part of the figure 2 is shown. The view shown here is only an example and is to be understood qualitatively, not quantitatively. But here you can clearly see the difference between what then came about diameter of the reinforcement compared to the original diameter. This change in diameter also produces a change in length and a change in the elastic elongation of the suspension element, which can be detected.

3 1 schematically shows an elevator system 10 according to the invention that is particularly suitable for carrying out the method according to the invention.

The elevator system also has two separate position measuring devices 7, 8 inside the elevator shaft, which is not shown in detail here.

In each of the position measuring devices 7, 8, a measuring cable 11 guided over deflection rollers 9 is provided. The lower deflection pulleys are below the floor of the elevator shaft and are not shown in detail here. The deflection rollers 9 of the position measuring devices 7, 8 are equipped with a known incremental rotary encoder that is not shown in detail here and, depending on the design, can detect minimal rotary movements and thus lifting movements of the cabin 3 or counterweight 6. For this purpose, the cabin and/or counterweight are articulated on the measuring cables 11 via drivers 12 . This is a so-called shaft copying, which is known as such in the technical field, but has hitherto been used purely for height measurements or controls of the lifting movement and not in duplicate and within the method according to the invention.

With the help of the position measuring devices 7, 8, an exact determination of the lifting distances or the travel distances S _G and S _K of the counterweight 6 of the cabin 3 is possible.

• Abwarten der Einlaufphase
• Sicherstellen eines gleichbleibenden definierten Gewichtszustandes der Kabine (leer)
• Ermittlung der Position der Kabine und des Gegengewichtes
• Verfahren der Kabine über alle Stockwerke
• Aufzeichnung und ständiger Vergleich des Verfahrweges der Kabine und des Gegengewichtes
• Ermittlung der einzelnen Abweichnungen der elastischen Dehnung
• Speichern der einzelnen Abweichungen als Basiskurve
• Bestimmung z.B. gemäß: Verfahrweg SG (Bewegung des Gegengewichts) = Verfahrweg S_K (Bewegung der Kabine) + x + y , wobei x = Abweichnungen aus elastischem Verhalten (zeitlicher gleichmäßige Anstieg in Korrelation zur Ablegereife in der Kurve), y = Alle anderen Einflüsse (z.B. Aufklettern, Riemenriss etc. Sprunghaftes Verhalten in Kurve)
• Durchführung weiterer Messungen und Vergleich mit Basiskurve
• Bewertungskriterien: Wenn Grenzwert erreicht, dann ablegen, Wenn Sprungfunktion erkannt, dann Kontrolle.

In the case of a procedural determination of the discard state of the suspension element based on the changed elastic elongation exceeding a threshold value, the following sequence for carrying out the method according to the invention would be possible, for example:

• Wait for the running-in phase
• Ensuring a constant defined weight status of the cabin (empty)
• Determination of the position of the cabin and the counterweight
• Movement of the cabin over all floors
• Recording and constant comparison of the travel of the car and the counterweight
• Determination of the individual deviations of the elastic strain
• Saving the individual deviations as a base curve
• Determination, for example, according to: travel SG (movement of the counterweight) = travel S _K (movement of the cabin) + x + y, where x = deviations from elastic behavior (timely uniform increase in correlation to the discard point in the curve), y = all other influences (e.g. climbing, broken belt etc. Erratic behavior in curves)
• Carrying out further measurements and comparison with base curve
• Evaluation criteria: If the limit is reached, then put it down, if the jump function is recognized, then check.

Reference List (part of the description)

1

carrying means

2

reinforcement / cord

3

elevator car

4

pulley

5

drive roller

6

counterweight

7

position measuring device

8th

position measuring device

9

Pulley with incremental encoder

10

elevator system

11

measuring rope

12

carrier of the weight

13

driver of the cabin

20

filaments of the reinforcement

SG

Counterweight travel/stroke

SK

Travel/lift of the cabin

Claims (8)

1. Method for detecting the state of wear of suspension means (1) of elastomeric material within a suspension or lift system (10), which has a cage (3) or a carrying device, which is connected by a suspension means (1) running over deflecting or driving rollers (4, 5) to a counterweight (6), wherein the suspension means has in its longitudinal direction strengthening supports (2) or reinforcing elements embedded in the body of the suspension means, preferably formed as cords twisted from filaments (20), wherein, after a running-in phase of the suspension lift system, selected physical properties of the suspension means (1) are determined as initial values and stored and subsequently, during operation, corresponding physical properties of the suspension means (1) are periodically or permanently set in relation to the initial values as current values and, if predetermined threshold values for the differences between initial values and current values are exceeded, a warning signal is given or replacement of the suspension means (1) is requested, characterized in that the length of the suspension means (1) and the elastic elongation of the suspension means in a defined lifting action during operation are determined as initial values and stored and subsequently the respectively current values of the length of the suspension means and the elastic elongation of the suspension means are periodically or permanently set in relation to the initial values, wherein by means of position measuring devices (7, 8) the positions both of the cage (3) and of the counterweight (6) within the lift system (10) or in the lift shaft are determined and from them both the initial length L_initial and the current length L_current of the suspension means (1) and the different initial travelling distances S_K and S_G of the cage (3) and the counterweight (6) caused by elastic elongation of the suspension means are determined, wherein the change in length of the suspension means ΔL = L_initial - L_current and the change in the initial ratio of the travelling distances of the cage and the counterweight S_K-initial / S_G-initial are set in relation to the current ratio of the travelling distances of the cage and the counterweight S_K-current / S_G-current as differences and from them the change in the elastic elongation of the suspension means (1) is calculated or determined.
2. Method according to Claim 1, in which the initial values and the current values of the lengths and the elastic elongation of the suspension means (1) in a predetermined, defined identical state of the suspension or lift system (10) are determined and calculated.
3. Method according to Claim 1 or 2, in which the initial values and the current values of the elastic elongation of the suspension means (1) in a defined lifting action of the suspension lift system (10) are determined and calculated.
4. Method according to one of Claims 1 to 3, in which a temporary or permanent recording and storage of the positions both of the cage (3) and of the counterweight (6) takes place.
5. Method according to Claim 4, in which a percentage frequency of specific identical or similar lifting actions is determined and set in correlation with the determined differences and/or predetermined threshold values.
6. Lift system for carrying out the method according to Claims 1 to 5, with a cage (3) or carrying device, which is connected by a suspension means (1) running over deflecting or driving rollers (4, 5) to a counterweight (6), wherein the suspension means has in its longitudinal direction strengthening supports (2) or reinforcing elements embedded in the body of the suspension means, wherein the lift system (10) has at least one separate position measuring device (7, 8) for the positions of the cage and/or the counterweight.
7. Lift system according to Claim 6, in which the lift system (10) has within a lift shaft at least one separate position measuring device (7, 8) in the form of measuring cables (11) or measuring bands led over deflecting rollers (9), wherein an incremental rotary encoder is provided in at least one of the deflecting rollers (9) of the position measuring device and the cage (3) and/or the counterweight (6) are articulated on the measuring cables (9) or measuring bands by means of driver lugs (12, 13).
8. Lift system according to Claim 6 or 7, in which a separate position measuring device (7, 8) is provided for the positions of either the cage (3) or the counterweight and an incremental rotary encoder is provided in one of the deflecting rollers or driving rollers of the suspension means for the determination of the position of the other part (cage or counterweight), respectively.

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