Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B66—HOISTING; LIFTING; HAULING
  • B66B—ELEVATORS; ESCALATORS OR MOVING WALKWAYS
  • B66B7/00—Other common features of elevators
  • B66B7/12—Checking, lubricating, or cleaning means for ropes, cables or guides
  • B66B7/1207—Checking means
  • B66B7/1215—Checking means specially adapted for ropes or cables
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B66—HOISTING; LIFTING; HAULING
  • B66B—ELEVATORS; ESCALATORS OR MOVING WALKWAYS
  • B66B7/00—Other common features of elevators
  • B66B7/12—Checking, lubricating, or cleaning means for ropes, cables or guides
  • B66B7/1207—Checking means
  • B66B7/1215—Checking means specially adapted for ropes or cables
  • B66B7/123—Checking means specially adapted for ropes or cables by analysing magnetic variables
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B66—HOISTING; LIFTING; HAULING
  • B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
  • B66C15/00—Safety gear

Definitions

• the invention relates to a method for determining a rope condition of a lifting rope of a lifting system according to patent claim 1 and a lifting system according to patent claim 15.
• An arrangement for monitoring an elevator having an elevator rope is known.
• the elevator rope is guided past an inductive sensor positioned so that a magnetic field generated by the inductive sensor, which extends at least partially across the elevator rope, is evaluated by a control device.
• An improved method for determining the rope condition of a hoisting rope of a hoisting system can be provided by providing a sensor device, a control unit with an evaluation device, a data interface connected to the evaluation device for data transmission, a data memory connected to the evaluation device for data transmission, and a hoisting rope with a plurality of wires. At least one sample set of several sample signal curves is stored in the data memory. Each sample signal curve is assigned information about a wire break.
• the data interface is connected to the sensor device for data transmission, wherein at least one section of the hoisting rope is moved past the sensor device.
• the sensor device provides a second sensor signal, which characterizes an interaction between the sensor device and the hoisting rope moved past the sensor device, via the data interface of the evaluation device.
• the evaluation device determines a second signal curve of the second sensor signal over the rope section. The evaluation device determines by assigning a the second signal waveform of the sample set matching a wire break in the section of rope moving past the sensor device.
• the information about the wire break can be designed such that the information has an assignment to a wire break or a multiple wire break and/or an assignment to a cable defect class.
• the sample signal curve can, for example, have information about at least one triangular curve and/or another characteristic value such as a density of zero crossings (a zero crossing is characterized by a change in the sign of the signal) and/or a number of zero crossings, a minimum and/or maximum peak value and/or a sequence of a change in sign of a signal curve section.
• the sample signal curve can, for example, be stored in the data memory in tabular form and/or as a mathematical function, for example as a mathematical series and/or spline and/or polynomial.
• the evaluation device can apply a pattern recognition, in particular a time warping algorithm, in particular a dynamic time warping algorithm and/or fast Fourier transformation and/or a wavelet transformation, in particular a direct wavelet transformation, in order to assign the pattern signal curve to the second signal curve and/or the second signal curve of the sensor signal to the first reference characteristic.
• a pattern recognition in particular a time warping algorithm, in particular a dynamic time warping algorithm and/or fast Fourier transformation and/or a wavelet transformation, in particular a direct wavelet transformation, in order to assign the pattern signal curve to the second signal curve and/or the second signal curve of the sensor signal to the first reference characteristic.
• At least one threshold characteristic with at least a plurality of different threshold values is stored in the data memory.
• the evaluation device determines a deviation between the second signal curve and the first reference characteristic.
• the evaluation device compares the deviation with the threshold characteristic. If at least one of the threshold values of the threshold characteristic is exceeded, the evaluation device verifies at least the information about the wire break. This allows the detection rate of the respective wire break to be further increased or the reliability of the detection to be further increased.
• the lifting system lifts a load of at least 20 t up to and including 10,000 t, with the second cable section being moved past the sensor device when lifting or lowering the load. This eliminates the need for additional measurement runs that This would interrupt regular production operations. Furthermore, the second sensor signal is improved by stretching the lifting rope under load.
• FIG 1 shows a schematic representation of a lifting system 10.
• the lifting system 10 is designed, for example, as a crane, in particular, for example, as a gantry crane.
• the lifting system 10 can, for example, be designed to be mounted in a large-scale industrial production facility, for example, in a building of a continuous casting machine or a cast-rolling composite plant, or another building used for steel or metal production, in order to lift heavy objects, in particular, for example, ladles and/or steel slabs and/or steel coils, using a lifting rope 20 of the lifting system 10.
• the lifting system 10, in particular the lifting rope 20 is subject to high loads and is subject to corresponding wear and aging.
• the lifting rope 20 may only be used as long as it is not worn out and ready for disposal.
• the control unit 15 has a data memory 35, an evaluation device 40, and a data interface 45.
• the data interface 45 is connected to the evaluation device 40 via a first data connection 50.
• the evaluation device 40 is connected to the data memory 35 via a second data connection 55.
• the data interface 45 is connected to the sensor device 25 via a third data connection 60.
• FIGS 2A and 2B show the sensor device 25 from different perspective views on the lifting rope 20.
• FIG 3 shows a flowchart of a method for operating the FIG 1 and 2A, 2B shown lifting system 10.
• FIG 4 shows a schematic first diagram of a first reference characteristic 100.
• FIG 5 shows a schematic second diagram of a second signal curve 120 of a second sensor signal over a second cable position p2(I).
• FIGS 6A to 6F each show an example sample signal curve of the sample set.
• FIG 7 shows a third schematic diagram of the first reference characteristic 100 with the associated second signal curve 120.
• FIG 8 shows an evaluation of wire breaks B plotted against the first rope position p1(I).
• a minimum speed, a predefined maximum threshold value M related to a reference length and the sample set of sample signal curves are stored in the data memory 35 (cf. FIGS 6A to 6F ).
• Each sample signal waveform of the sample set is assigned a type of wire break or a multiple wire break or a cable defect class (label).
• FIGS 6A to 6F Example sample signal waveforms are given.
• Each sample signal waveform has a different characteristic and represents a different wire break B and/or multiple wire break formed from several wire breaks B essentially at the same first cable position p1(I) and/or a different cable defect class. The characteristic is primarily characterized by the shape of the sample signal waveform and/or its features.
• FIG 6A The first sample waveform shown shows a double wire break that is close to another single wire break.
• FIG 6B shows a 12-fold wire break, which correlates with the lifting rope 20 being ready for discard.
• FIG 6C For example, shows a single wire break with a nearby quadruple wire break.
• FIG 6D shows, for example, a 6-fold wire break.
• FIG 6E shows, for example, a single wire break.
• FIG 6F shows a 4-way wire break (with negative amplitude).
• the lifting rope 20 is mounted in the lifting system 10 essentially in a new or barely worn condition, and the sensor device 25 is permanently mounted on the lifting rope 20, so that during each lifting or lowering operation or during each movement of the lifting rope 20 by the lifting device 30, the lifting rope 20 is guided past the sensor device 25.
• a second method step 310 for example, the lifting rope 20 is completely unwound or completely wound up once.
• a crane hook of the lifting system 10 can be completely raised and moved to the lowest point within the usage range of the lifting system 10.
• a starting point 95 of the lifting rope 20 is thereby defined.
• the starting point 95 serves as a reference point on the lifting rope 20.
• the first rope position p1(I) can be referenced and related to the starting point 95.
• a third method step 315 the lifting cable 20 is guided past the sensor device 25 at the minimum speed in a first direction of travel.
• the minimum speed can be at least 0.1 m/s, in particular at least 0.2 m/s.
• the speed at which the lifting cable is moved should not exceed 50 m/s.
• the sensor device 25 is activated in the third method step 315.
• the magnetic field generator provides the magnetic field.
• the magnetic field of the magnetic field generator acts on the lifting cable 20 and the individual wires of the lifting cable 20.
• the ferromagnetic and/or austenitic material of the lifting cable 20 changes the magnetic field flux.
• the magnetic field sensor is arranged at a distance from the magnetic field generator and provides a first sensor signal depending on the detected magnetic field.
• the first sensor signal is transmitted via the third data connection 60 to the data interface 45 and from the data interface 45 via the first data connection 50 to the evaluation device 40.
• the evaluation device 40 detects the first sensor signal.
• the control unit 15 can filter and/or smooth the first speedometer signal before further processing, with averaging being used, in particular, for smoothing.
• the control unit 15 can have an additional second filter for filtering.
• the lifting rope 20 is wound up or unwound over an available rope length starting from the starting point up to a maximum movable end 105 and guided past the sensor device 25.
• a fourth method step 320 following the third method step 315 the evaluation device 40 determines a first cable position p1(I) relative to the starting point 95, which is assigned to the first sensor signal, on the basis of the distance a between the second sensor unit 75 and the first sensor unit 70 and the speed information of the first tachometer signal via the hoist cable 20.
• a first sensor signal is determined at a distance of a certain length from the starting point 95 at the respectively assigned first cable position p1(I).
• the evaluation device 40 determines a first signal profile of the first sensor signal for the respectively assigned first cable position p1(I) between the start position 95 and the end 105.
• the evaluation device 40 stores the first signal profile in the data memory 35 as a first reference characteristic 100. It is further assumed that the new lifting cable 20 is essentially free of wire breaks B, or has only very few - e.g., fewer than 10 - wire breaks over the entire detectable cable length.
• the evaluation device 40 preferably stores a first time information associated with the first reference characteristic 100, which essentially corresponds to the detection time of the first sensor signal.
• the first reference characteristic 100 forms a first fingerprint of the lifting rope 20, which is individual for the respective lifting rope 20.
• the first sensor signal correlates with a stray flux D of a magnetic flux in the hoisting rope 20.
• the stray flux D of the first sensor signal corresponds to an interruption/weakening of the magnetic flux, for example, due to one or more wire breaks B at the assigned first rope position p1(I).
• the first reference characteristic 100 (cf. FIG 4 ), for example, exhibits a jagged first profile of the first sensor signal across the first cable position p1(I). The greater the amplitude of the first sensor signal at an associated first cable position p1(I), the more strongly/severely the leakage flux D changes at the respective associated first cable position p1(I). Therefore, if the first sensor signal has a high amplitude, the hoisting cable 20 exhibits one or more wire breaks B at the respective associated first cable position p1(I).
• the evaluation device 40 can determine the threshold characteristic with at least the first threshold based on the first reference characteristic 100.
• the evaluation device 40 determines an envelope around the first reference characteristic 100 based on the first reference characteristic 100. Based on the envelope, the evaluation device 40 determines the threshold characteristic.
• At least the first threshold and preferably the additional threshold values further away from the first threshold can, for example, each have a predefined minimum distance from the envelope of the first reference characteristic 100.
• a cable section 110 of the lifting cable 20 is guided past the sensor device 25 at the minimum speed.
• the cable section 110 can be located between the starting point 95 and the end 105 of the lifting cable 20.
• the cable section 110 can be shorter than the maximum length of the lifting cable 20 between the starting point 95 and the end 105 of the lifting cable 20.
• the cable section 110 can also extend completely between the starting point 95 and the end 105 of the lifting cable 20, so that a maximum available length of the lifting cable 20 is guided past the sensor device 25.
• the first sensor unit 70 provides a second sensor signal based on the interaction between the first sensor unit 70 and the cable section 110 of the hoisting cable 20 being guided past, which second sensor signal characterizes an interaction between the sensor device 25 and the hoisting cable 20 moving past the sensor device 25.
• the first sensor unit 70 provides the second sensor signal to the evaluation device 40 via the data interface 45.
• the minimum speed is an important prerequisite for the second sensor signal to have plausible and usable values for the leakage flux D over the entire signal curve and thus to be further processed by the evaluation device 40.
• the speedometer wheel 80 rolls on the hoisting cable 20 at a distance a offset from the first sensor unit 70, and the speed sensor 90 provides, for example, information about the speed of the hoisting cable 20 as part of a second speedometer signal via the third data connection 60 to the data interface 45 and via the second data connection 55 to the evaluation device 40.
• the evaluation device 40 detects the second speedometer signal.
• the evaluation device 40 determines the second cable position p2(I) within the cable section 110 for the respectively detected second sensor signal on the basis of the distance a and the speed information of the second speedometer signal.
• the evaluation device 40 compares the speed information of the second speedometer signal with the minimum speed stored in the data memory 35. If the minimum speed is undershot, the further method steps are discontinued, since the leakage flux D detected at the second signal position p2(I) is deemed unusable for further evaluation. If the minimum speed is exceeded, the evaluation device 40 proceeds to a ninth method step 345.
• the evaluation device 40 determines a second signal curve 120 of the second sensor signal over the cable section 110 (cf. FIG 5 ).
• the second signal curve 120 is assigned to the respectively determined second cable position p2(I) within the cable section 110.
• the second cable position p2(I) extends, for example, between a starting point of the detection of the leakage flux D with the minimum speed to an end point of the detection of the leakage flux D with the minimum speed.
• the starting point can be different from the starting point 95 and/or the end point can be different from the end 105.
• the evaluation device 40 can check a second running direction based on the second tachometer signal with which the cable section 110 is guided past the sensor device 25 in the sixth method step 330. If the second running direction corresponds to the first running direction of the first reference characteristic 100, the evaluation device 40 continues with the determined second signal curve 120.
• the evaluation device 40 inverts the second signal curve 120 by inverting the determined second cable position p2(I) with reference to the starting point and the end point, for example by mirroring at a reversal point located between the starting point and the end point, for example, centrally, and accordingly updates the second signal curve 120 of the sensor signals via the respectively assigned second cable position p2(I) within the cable section 110.
• the evaluation device 40 compares the second signal curve 120 of the second sensor signals over the cable section 110 with the first reference characteristic 100 and assigns the second signal curve 120 to a reference section 115 of the first reference characteristic 100, for example by means of pattern recognition and/or Fast Fourier Transformation and/or a Wavelet Transformation, in particular a Direct Wavelet Transformation (cf. FIG 7 ).
• the evaluation device 40 can determine a matrix profile for each of the first reference characteristic 100 and the second signal waveform 120.
• the matrix profile can be a vector that represents a normalized Euclidean distance between a subsequence of the first reference characteristic 100 and the second signal waveform 120.
• the first reference characteristic 100 can represent a time- and location-related series (x1), with the second signal waveform 120 representing a nearest neighbor of a series (x2).
• the evaluation device 40 can, for example, break down both the first reference characteristic 100 and the second signal waveform 120 into subsequences and select them as characteristic patterns for the time- or location-related series.
• the evaluation device 40 selects intervals for the first reference characteristic 100 and/or the second signal curve in which the first reference characteristic 100 has deflections in its amplitude and/or signal shape sections in its curve which indicate one or more wire breaks B.
• the evaluation device 40 can efficiently determine a distance within a selected subsequence of the first reference characteristic 100 to each subsequence of the second signal curve 120 and determine the smallest distance within the matrix.
• the evaluation device 40 can, for example, determine recurring patterns or motifs between the first reference characteristic 100 and the second signal profile 120. Using the recurring patterns or motifs, the evaluation device 40 can, for example, assign the second signal profile 120 to a reference section 115 of the first reference characteristic 100.
• the evaluation device 40 assign the second signal profile 120 to a reference section 115 of the first reference characteristic 100, preferably by means of a Fast Fourier Transformation (FFT for short) and/or preferably a time-warping algorithm, in particular a dynamic time-warping algorithm.
• the time-warping algorithm in particular the dynamic time-warping algorithm, has the advantage that an elongation of the lifting cable 20 over time and/or an elasticity of the lifting cable 20 and/or a slip of the speedometer wheel 80 on the lifting cable 20 can be compensated and/or taken into account.
• the Fast Fourier Transformation has the advantage of providing a very precise amplitude characteristic, which can promote local assignments between the first reference characteristic 100 and the second signal curve 120 even without the presence of wire breaks.
• the dynamic time warping algorithm and/or the Fast Fourier Transformation thus provides an improved match between the second signal curve 120 and the first reference characteristic 100 within the framework of pattern recognition.
• the evaluation device 40 can reliably assign the second cable position p2(I) of the second sensor signal to the respective first cable position p1(I) of the first reference characteristic 100 on the basis of the first reference characteristic 100.
• the evaluation device 40 further determines at least one matching region 116 of the second signal curve 120 within the reference section 115 of the first reference characteristic 100, in which the second signal curve 120 substantially matches the first reference characteristic 100 (cf. FIG 4 ).
• the evaluation device 40 further determines, for example, a deviation range 117 in which the second signal curve 120 deviates from the reference section 115 of the first reference characteristic 100 (cf. FIG 4 ).
• the deviation range 117 in FIG lies, for example, between two agreement ranges 116.
• the hoisting rope 20 has been used only to a limited extent since the first reference characteristic 100 was determined, it may be the case that there is essentially an identity between the second signal curve 120 and the reference section 115 and the evaluation device 40 does not determine a deviation range 117.
• the evaluation device 40 breaks down the deviation range 117 and/or the deviation ranges 117, in which the second signal curve 120 deviates from the first reference characteristic 100, into a respective individual evaluation range 118, 119 (cf. FIG 5 ).
• the analysis can be performed, for example, based on a profile, for example in the area of a peak, for example, before and after a peak.
• the evaluation device 40 can determine the first cable position p1(I) of the respective evaluation area 118, 119 in a defined manner.
• the evaluation device 40 compares the at least one evaluation range 118, 119 with the sample set of sample signal waveforms.
• each of the evaluation ranges 118, 119 of the second signal waveform 120 is preferably compared with a plurality of sample signal waveforms of the sample set (cf. FIGS 6A to 6F ), for example in its form, compared and/or evaluated.
• the evaluation device 40 can, for example, apply a pattern comparison method. Furthermore, the evaluation device 40 selects, for example, the sample signal waveform from the sample set that exhibits the greatest correspondence with the respective evaluation range 118, 119 of the second signal waveform 120. As already explained, the information about a wire break B and, if applicable, a wire break number B and/or the cable defect class is stored in the data memory 35 for each sample signal waveform.
• the evaluation device 40 can identify the corresponding assigned wire break B based on the correspondence of the evaluation area 118, 119 with one of the sample signal curves and, via the assignment of the second signal curve 120 to the first reference characteristic 100, determine the first cable position p1(I) assigned to the wire break B or the multiple wire breaks B based on the first reference characteristic 100 and store the respective first cable position p1(I) for the determined wire break B in the data memory 35.
• the evaluation device 40 can determine a deviation b between the second signal curve 120 and the first reference characteristic 100 at the first cable position p1(I).
• the evaluation device 40 can determine a number of wire breaks B per reference length, preferably across the entire updated second reference characteristic 125, based on a predefined reference length stored in the data memory 35.
• the reference length can, for example, correspond to six times the outer diameter or, for example, thirty times the outer diameter of the lifting rope 20.
• the evaluation device 40 for example, sums up the wire breaks B determined within the predefined reference length.
• a fourteenth method step 370 which follows the thirteenth method step 365, the evaluation device 40 compares the determined number of wire breaks B per reference length with a predefined maximum threshold value M, which is stored in the data memory 35.
• the predefined maximum threshold value M corresponds to the value at which the lifting rope 20 is ready for discarding in order to be subjected to the loads permitted for the lifting rope 20.
• the maximum threshold value M is in FIG 8 represented by a dashed line.
• the evaluation device 40 provides information about the discard readiness of the lifting rope 20 at the data interface 45 if the predefined maximum threshold value M is exceeded by the determined number of wire breaks B per reference length.
• the evaluation device 40 can determine a maximum MAX of the determined number of wire breaks B within the reference length.
• the maximum MAX can be smaller than the maximum threshold value M.
• the evaluation device 40 additionally determines a minimum distance c, for example by calculating the difference, between the maximum MAX of the determined number of wire breaks B per reference length and the predefined maximum threshold value M.
• the evaluation device 40 Based on the minimum distance c, the evaluation device 40 provides warning information or, based on the time interval between the determination of the second signal curve 120 and the first reference characteristic 100, a prediction about an impending discard readiness of the lifting rope 20 at the data interface 45.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Length Measuring Devices With Unspecified Measuring Means (AREA)

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Citations (4)

• 2024
  • 2024-03-28 EP EP24167436.5A patent/EP4624405A1/fr active Pending
• 2025
  • 2025-03-04 WO PCT/EP2025/055859 patent/WO2025201812A1/fr active Pending

Patent Citations (4)

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