EP0563836A2 - Method to measure the driving capability of a transporting device - Google Patents

Abstract

The invention relates to a method of measuring the driving capability of a drive, provided with a carrying rope run over a driving pulley, of a hoisting system, in particular a lift system, with a car hanging on one end of the carrying rope and a counterweight hanging on the other end of the carrying rope, the carrying rope being relieved of load on one side until the driving pulley slips under the carrying rope in sliding friction such that a measured value is determined in the process from which the driving capability is deduced, and to a lift system for carrying out the method. <IMAGE>

Description

The invention relates to a method and an elevator system for measuring the driveability of a drive of a conveyor system provided with a supporting cable guided over a traction sheave, in particular an elevator system with a car hanging on one end of the supporting cable and a counterweight hanging on the other end of the supporting cable.

Elevator systems that are driven by a traction sheave suspended from a suspension cable must be checked for their driving ability at intervals of two years. The driveability indicates the slip resistance of the friction connection between the suspension cable and the traction sheave.

According to the technical rules for lifts, edition July 1989, TRA102, published by the Association of Technical Inspection Associations e.V., Essen, the car loaded with 1.5 times the nominal load must be stopped when driving downwards with the greatest possible braking. It is desirable if the ropes slide over the traction sheave, since then the lowest friction value acts between the rope and traction sheave. Under these conditions, the car loaded with 1.5 times the nominal load must come to a standstill again.

According to the test specification, a higher load on the elevator system than in normal operation is therefore brought about. However, the test does not provide any information as to whether the system would slip under a slightly greater load than 1.5 times the nominal load. Furthermore, a rope slide is often used during the test not reached, so that the static friction between the rope and the pulley still works. Furthermore, it is disadvantageous that the entire elevator installation is subjected to high stresses due to the increased load of 1.5 times the nominal load and thus wears out more. Furthermore, loading the car with additional weights up to 1.5 times the nominal load is time-consuming and labor-intensive.

DE 39 11 391 A1 discloses a method for detecting physical parameters, in particular movement parameters of a goods and / or elevator, in which, among other things, the slip resistance (driving ability) of the cable driven by the traction sheave is determined. The driving capacity of the cable is determined with a force transducer, which is arranged between the cable and a fixed point by means of a cable clamp. By turning the traction sheave, the pulling force acting on the cable pull is increased until either a determined limit value is reached or the cable begins to slide on the traction sheave.

A disadvantage of this method is that the tensile force additionally acting on the cable pull by the force measuring signal transmitter considerably increases the loads on the elevator installation. Furthermore, a slipping of the cable on the traction sheave is not achieved if a further increase in tractive force is excluded for safety reasons.

The object of the invention is to provide a measuring method for the driving ability of a conveyor system, in particular an elevator, in which the rope slips safely and the elevator system thereby is not exposed to increased stress.

This object is achieved by a method of the type mentioned in that the suspension cable is relieved on one side until the traction sheave slips under the suspension cable in sliding friction, so that a measured value is determined from which the propulsion capacity is deduced.

The object is also achieved with a conveyor system of the type mentioned, a fixed stop being provided for relieving the supporting cable for the car or the counterweight and a force measuring device being arranged in the flow of force between the stop and the counterweight.

The advantage here is that by relieving the cable pull on one side, the cable tension ratio is brought into greater imbalance without the entire elevator installation being subjected to greater stress. The rope tension ratio is changed until the traction sheave slips under the pull rope. This ensures that the tensile force transmitted from the traction sheave to the rope by friction is transmitted by means of sliding friction.

In an advantageous embodiment it is provided that the car is placed on the measuring device which is arranged in the elevator shaft in a stationary manner, the traction sheave being rotated further in the same direction of rotation until the traction sheave slips under the supporting cable. By placing the car on the measuring device, the weight of the car hanging on the suspension cable is reduced. The weight relief is from the measuring device registered. When the load is relieved, the traction sheave begins to slip under the suspension cable. This means that the critical rope tension ratio has been reached and the driving ability of the suspension rope / traction sheave connection can be calculated.

Alternatively, the counterweight can be placed on the measuring device instead of the car.

In a further embodiment it is provided that the measuring device is arranged on a buffer assigned to the car or the counterweight in the elevator shaft pit. The measuring device can thus be installed in the elevator shaft of the elevator system to be tested with little effort.

If the measuring device is arranged in the elevator shaft so that the point of contact of the car or the counterweight is within the normal driving range of the elevator system, the driving ability is determined on a rope section which is subject to wear and tear due to normal operation of the elevator system.

In another embodiment of the method it is provided that the car is connected to a fixed point arranged above it via an auxiliary rope and the measuring device, the traction sheave being rotated further in the same direction of rotation after hanging up until the traction sheave slips under the suspension rope. The auxiliary rope absorbs part of the weight of the car. The relief is recorded with the measuring device.

Alternatively, the counterweight can be hung on the auxiliary rope with the measuring device instead of the car.

In a preferred embodiment it is provided that the auxiliary rope is led from the elevator shaft into a machine room arranged above to a fixed point. The measuring device can be conveniently arranged between the auxiliary rope and the fixed point.

The length of the auxiliary rope is advantageously chosen so that the suspension point of the car or counterweight is within the normal driving range, preferably in the most frequently used driving range of the elevator system. This measures the ability to drive on a section of rope that is subject to great wear.

In another embodiment it is provided that a rope clamping device is attached to the support rope, which is placed on the stationary measuring device, after the attachment the traction sheave is rotated in the same direction until the traction sheave slips under the support rope. With this method, a relief according to the invention can be achieved either on the car side or on the counterweight side of the suspension cable, so that when the traction sheave slips under the suspension cable, the critical cable tension ratio, i.e. the driving ability can be calculated.

Pressure transducers, strain gauges or spring scales are advantageously used as measuring devices. Spring scales allow direct reading of the relieving weight force. The measured values of Pressure transducers or strain gauges can advantageously be temporarily stored on data loggers or directly digitally processed on a microcomputer. As an alternative to this, the measured values can also be displayed analogously on an x / y recorder. The measured relief over time is advantageously plotted as a load curve.

In addition to measuring the driving ability between the traction sheave and the suspension cable, the same measuring arrangement can also be used to determine the actual weight of the car, counterweight and the half load from the difference. All that is required is that when the car or counterweight is attached or suspended, the supporting cable is fixed to the traction sheave with a cable clamp, so that after the traction sheave is turned further, the supporting cable leading to the attached or suspended car or counterweight sags and the weight of the car or Counterweight can be measured with the measuring device.

In the following, three preferred variants of the method are explained with reference to the attached figures, with further advantageous configurations being shown in the figures.

Fig. 1

zwei beispielhafte Meßkurven,

Fig. 2

eine Aufzuganlage als Schema,

Fig. 3

eine Aufzuganlage mit Meßvorrichtung und aufgesetztem Aufzug,

Fig. 4

eine Aufzuganlage mit Meßvorrichtung und aufgesetztem Gegengewicht,

Fig. 5

eine Aufzuganlage mit Hilfsseil befestigt am Fahrkorb,

Fig. 6

eine Aufzuganlage mit Hilfsseil befestigt am Gegengewicht,

Fig. 7

eine Aufzuganlage mit am fahrkorb- bzw. gegengewichtsseitigen Tragseilteil befestigter Klemmvorrichtung.

The figures show in detail:

Fig. 1

two exemplary measurement curves,

Fig. 2

an elevator system as a scheme,

Fig. 3

an elevator installation with a measuring device and an attached elevator,

Fig. 4

an elevator system with measuring device and counterweight,

Fig. 5

an elevator system with auxiliary rope attached to the car,

Fig. 6

an elevator system with auxiliary rope attached to the counterweight,

Fig. 7

an elevator system with a clamping device attached to the car or counterweight-side support cable part.

FIG. 1 shows two measurement curves 17 by way of example. The steep rise in the measurement curve according to FIG. 1 represents the placing of the car or the counterweights on the measuring device. The maximum is reached when the static friction acting between the suspension cable and the traction sheave is exceeded. When the traction sheave is turned further, a short transient action takes place to the relief value M1 or M2 relevant for the method according to the invention with sliding friction acting between the suspension cable and the traction sheave.

Die beschriebenen Berechnungen und Formeln vernachlässigen das Seilgewicht der Tragseile, das Gewicht der Hängekabel, die die elektrische Verbindung zwischen Fahrkorb und Maschinensteuerung bilden, und das Gewicht eventuell vorhandener Unterseile.In FIG. 2, G denotes the weight of the counterweight 6, F the weight of the empty car 3, which counteracts the deflection of the suspension cable 2 via a traction sheave 1. In the same direction as the weight of the car 3, the weight of the load L acts, so that there is a rope tension S 1 in the counterweight-side support cable part 5 and one in the car-side support cable part 4 Rope tension S₂ results. The nominal load is designated with Q. A rope tension ratio can be defined from this, which results as follows:

The calculations and formulas described neglect the weight of the suspension ropes, the weight of the suspension cables that form the electrical connection between the car and the machine control, and the weight of any lower ropes that may be present.

In general, the counterweight 6 in elevator systems is dimensioned such that it corresponds to the weight of the empty car 3 plus half the nominal load. The unfavorable operating case occurs when the empty car 3 is stopped in the upward movement. All other operating cases up to loading the car with nominal load have a lower rope tension ratio.

In the test method according to the invention, on the one hand, it should be ensured that the test is carried out with sliding ropes, and, on the other hand, the maximum possible load is determined which the traction sheave 1 can just hold due to the sliding friction.

To determine the maximum possible load, the rope tension ratio is increased by relieving one side until the traction sheave 1 slips under the supporting ropes 2. The relief force required for this type of operation is measured and from this the driving ability of the Traction sheave 2 calculated.

Since the driving ability for conventional elevator systems is almost independent of the load, the load can be determined from the measured value if the car weight and counterweight are known, which the system can still hold in the state of sliding friction.

In this way it is possible to make a statement about the reserve that the system has in the case of sliding friction compared to 1.5 times the overload.

Basically, three variations of the measurement are possible, whereby for each variant the rope tension ratio can be increased by relieving the load on the counterweight or car side. This results in a total of six different measurement orders:
Place the car or counterweight on the measuring device in the pit.
Attachment of an auxiliary rope to the car or counterweight, relief against a fixed point in the machine room on the measuring device.
Attaching a clamping device on the supporting cables in the machine room on the car or counterweight side, relief by placing the clamping device on the measuring device in the machine room.

FIG. 3 shows the method according to the invention, the measuring device 7 being mounted on the buffer 9 in the shaft pit 10. The car 3 is driven to the lower floor and then with the Return control or manually placed on the measuring device 7. After attaching the traction sheave 1 is rotated until the ropes 2 slip under the traction sheave 1.

Dabei beendet M₁ den Meßwert bei aufgesetztem Fahrkorb.The following rope tension ratio results at this operating point:

M 1 ends the measured value with the car in place.

Dabei bedeutet M₂ den Meßwert bei aufgesetztem Gegengewicht.FIG. 4 shows the method according to the invention, the measuring device being mounted on the buffer 9 in the shaft pit 10. The counterweight 6 is moved to the lower floor and then placed on the measuring device with the return control or by hand. After attaching the traction sheave 1 is rotated until the ropes 2 slip under the traction sheave 1. The following rope tension ratio results at this operating point:

M₂ means the measured value with the counterweight attached.

FIG. 5 shows the method, wherein an auxiliary rope 12 is fastened to the car 3 and is guided through the opening 18 for the ropes in the machine room floor 19 up to a fixed point 11 above the floor 19.

The measuring device 7 is set at this fixed point. The auxiliary rope 12 is attached to the measuring device 7 with a device.

The car 3 is moved downwards with the return control or by hand until the traction sheave 1 slips under the ropes 2.

Dabei bedeutet M₃ den Meßwert bei entlastetem Fahrkorb.The following rope tension ratio results in this operating state:

M₃ means the measured value with the car unloaded.

FIG. 6 shows the method in which an auxiliary rope 12 is fastened to the counterweight 6 and is guided through the opening 18 for the ropes 2 in the machine room floor 19 up to a fixed point 11 above the floor 19.

The measuring device 7 is placed on this fixed point 11. The auxiliary rope 12 is attached to the measuring device 7 with a device.

The counterweight 6 is moved downwards with the return control or by hand until the traction sheave 1 slips under the ropes 2.

Dabei bedeutet M₄ den Meßwert bei entlastetem Gegengewicht.The following rope tension ratio results at this operating point:

M₄ means the measured value with the counterweight relieved.

FIG. 7 shows the method, with a clamping device 14 being attached to the supporting cables. This is possible on the car side or on the counterweight side.

The clamping device 14 is placed on the measuring device 7, which is attached to a fixed point 11 in the machine room 13.

The car or the counterweight is moved downwards with the return control or by hand until the traction sheave slips under the ropes.

Dabei bedeutet M₅ den Meßwert bei entlastetem Fahrkorb.

Dabei bedeutet M₆ den Meßwert bei entlastetem Gegengewicht.The following rope tension ratio results at this operating point:

M₅ means the measured value with the car unloaded.

M₆ means the measured value with the counterweight relieved.

The measuring device is described below:
A pressure transducer is used for the measurement, which can be attached in a simple manner between a fixed point and the relief device for the car or counterweight. With this measuring method the Force curve recorded that the car or the counterweight generates from the moment of unloading until the traction sheave is driven through. The data is recorded in a data logger, which is not shown in detail because it is known, in order not to have to lay measuring lines.

The recorded force curve 17 is read from this data logger into a laptop 16, which then displays it on the screen. This curve profile can be printed out for the respective system using the printer.

The characteristic values characteristic of the system can be read from the course of the curve and are then available for further calculation.

If the pressure cell and laptop can be attached or used in the same room, it is possible to dispense with the data logger and read the force curve from the pressure cell directly into the laptop.

To calculate the maximum permissible overload, knowledge of the car weight, the counterweight and also the half load is required. This data is contained in the preliminary examination documents of the elevator examination book and can be adopted from there. If there are concerns about the correctness of this information due to changes or other measures, these values can also be determined with the existing measuring device.

After the car has been placed over the relief device and the suspension cables have slipped over the traction sheave, the system is installed in it Condition stopped via the braking device. Then the rope clamp is put on and the traction sheave is turned with the handwheel until slack rope forms on the car side. The measured value then corresponds to the weight of the empty car.

The same measuring method can be used for the counterweight if the measuring device is attached to the counterweight side.

The half load can be calculated from the car weight and the counterweight. This semi-load is loaded into the car as a check. The system is then driven electrically upwards and downwards, the motor current being measured using a clamp ammeter. With this method, the half load can be detected very precisely.

After removing the half load, the empty car is also moved electrically through the shaft, the currents for the upward direction and for the downward direction being determined. These can be recorded as plant characteristics.

In the next tests, simply checking these current values can be used to determine whether weight changes have been made to the system.

Wobei Ü die maximal zulässige Überlast ist.The maximum overload is determined as follows:
Since the rope tension ratio is almost independent of the load for conventional elevator systems, the maximum possible overload can be inferred from the measured values. First The following relationships apply:

Where Ü is the maximum permissible overload.

The measured values for the unloaded counterweight side and the unloaded car side are of different sizes. In this way, a simple control measurement is possible, via which the accuracy of the determined values can be confirmed.

Furthermore, after knowledge of the half load of the same measured values, a control calculation can also be made, so that a statement can also be made about the accuracy of the determined values and the resulting maximum overload.

The measurement data are evaluated as follows:
The measured values are determined from the recorded load curves and entered into the laptop's calculation program. The driving ability, the maximum overload and also the control values are determined via the program if several measurements have been carried out.

The system data, the measured values and the current values are saved for the tested elevator system and called up again during the next main test. This is a comparison of the current test data possible with those of previous years, so that a statement can be made about the temporal course of the driving ability and the decrease in the maximum possible overload. This makes it possible to estimate at an early stage when the driving ability is no longer sufficient and the traction sheave and suspension cables have to be replaced.

REFERENCE SIGN LIST

1

Traction sheave

2nd

Suspension cable

3rd

Car

4th

an end

5

other end

6

Counterweight

7

Measuring device

8th

Elevator shaft

9

buffer

10th

Pit

11

Benchmark

12

Auxiliary rope

13

Engine room

14

Rope clamp

15

stationary measuring device

16

Microcomputer

17th

Load curve

18th

Openings

19th

ground

Claims (14)

Method for measuring the driving ability of a conveyor system drive provided with a supporting rope (2) guided over a traction sheave (1), in particular an elevator system with a car (3) hanging at one end (4) of the supporting rope (2) and at the other end (5 ) of the suspension rope hanging counterweight (6), characterized in that the suspension rope (2) is relieved on one side until the traction sheave (1) slips under the suspension rope (2) in sliding friction, and a measured value is determined from which on the Driving ability is closed. A method according to claim 1, characterized in that the weight of the relief (M) is directly detected as a measured value with a measuring device (7) and that the driving ability (T) is determined as a critical rope tension ratio with

where F is the load on the support cable of the side of the traction sheave to be relieved before the relief and G is the load on the support cable on the other side of the traction sheave. Method according to Claim 2, characterized in that the car (3) is placed on the measuring device (7) which is arranged in a fixed position in the elevator shaft (8), the traction sheave (1) being rotated further in the same direction of rotation until the traction sheave (1 ) slips under the suspension cable (3). Method according to Claim 2, characterized in that the counterweight (6) is placed on the measuring device (7) which is arranged in a fixed position in the elevator shaft (8), the traction sheave (1) being rotated further in the same direction of rotation until the traction sheave (1 ) slips under the suspension cable (2). Method according to claim 3 or 4, characterized in that the measuring device is arranged on a buffer (9) assigned to the car or the counterweight in the elevator shaft pit (10). Method according to claim 3, 4 or 5, characterized in that the measuring device is arranged in the elevator shaft (8) so that the point of contact of the elevator car or the counterweight is within the normal travel range of the elevator system. Method according to Claim 2, characterized in that the car (3) is connected to a fixed point (11) above it via an auxiliary cable (12) and the measuring device (7), the driving pulley (1) being connected after the car (3) has been connected ) is rotated further in the same direction of rotation until the traction sheave (1) slips under the suspension cable (2). Method according to Claim 2, characterized in that the counterweight (6) is connected to a fixed point (11) above it via an auxiliary cable (12) and the measuring device (7), the traction sheave (1 ) is rotated further in the same direction of rotation until the traction sheave (1) slips under the suspension cable (2). Method according to claim 7 or 8, characterized in that the auxiliary rope is led from the elevator shaft (8) into a machine room (13) arranged above it to the fixed point (11). A method according to claim 7, 8 or 9, characterized in that the length of the auxiliary rope (12) is selected so that the suspension point of the elevator car or the counterweight is within the normal driving range, preferably in the most frequently used driving range, of the elevator system. A method according to claim 2, characterized in that a cable clamping device (14) is attached to the supporting cable, with which the measuring device, which is preferably arranged in a fixed position, is connected, the driving pulley being rotated further in the same direction after being placed on it until the traction pulley (1) slips under the suspension cable (2). Method according to one of the preceding claims, characterized in that pressure measuring cells, strain gauges or spring scales are used as the measuring device (7). Method according to one of the preceding claims, characterized in that the measuring device is connected to a data logger, an x / y recorder or a microcomputer (16) and the measurement data are recorded in the form of load curves (17). Elevator system for carrying out the method according to one of the preceding claims for measuring the driving ability of a conveyor system drive provided with a supporting cable guided over a traction sheave, in particular an elevator system with a car hanging on one end of the supporting cable and a counterweight hanging on the other end of the supporting cable according to one or more of the preceding claims, characterized in that a fixed stop for the car or the counterweight is provided to relieve the load-bearing cable and in the flow of force between the stop and Counterweight a force measuring device is arranged.

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