METHOD FOR DETERMINING A WEAR STATE, IN PARTICULAR FOR PREDICTING A REMAINING SERVICE LIFE AND / OR A REMAINING OPERATING TIME, OF AT LEAST ONE RUNNING STRAND OF A DEVICE AND DEVICE THAT USES THE AT LEAST ONE RUNNING STRAND FOR ITS INTENDED USE

Description

[0001] The invention relates to a method for determining a wear condition, in particular for predicting a remaining service life and / or a remaining operating time, of at least one running strand of a device using the at least one running strand for its intended use, in which method a position of strand segments of the at least one running strand is determined during operation of the device, wherein for each strand segment of the at least one running strand, when a load position L i of a load moved with the device changes to a subsequent load position L i+1, at least one wear parameter is determined, from which the wear condition of the at least one running strand is determined.Furthermore, the invention relates to a device which has at least one running strand and a strand guide means for the at least one running strand and a sensor device for detecting a movement speed of the strand guide means and / or a force acting on the at least one strand.

[0002] A running strand is a strand of a device which, when the device is used as intended, i.e. when it is in operation, is moved via strand guide means and is thereby deflected, i.e. bent (see, for example, the German VDI guideline 2358 from 2012, section 5.1).

[0003] Such a device may, for example, be a lifting device or a locking device.

[0004] A lifting device is a device designed to move a load, in particular to raise or lower it. A lifting device can be a load crane such as a tower crane, a harbor crane, a crawler crane, a luffing crane, or an elevator, which can be designed as a passenger or freight elevator. It is understood that an elevator is intended solely for the movement of an elevator car in or against the direction of gravity.

[0005] A moving leg of a lifting device can be designed as a lifting leg or an adjustable leg. The lifting leg allows the movement of a load to be moved with the lifting device in or against the direction of gravity, i.e., upwards or downwards. The adjustable leg enables the movement of adjustable, for example, pivotable lifting device elements such as booms or crane trolleys.

[0006] A closure device can be provided for opening a weir or lock, in which closure gates, also referred to as gates, can be opened or closed, for example, by moving chains. In particular, the closure gates can be horizontally movable, i.e., from a closed position to an open position or vice versa.

[0007] Strand guide means are all means that guide the running strand during its movement and can, for example, be designed as discs such as rope sheaves, as rollers such as rope pulleys, or as drums such as rope drums onto which the running strand can be wound or from which the running strand can be unwound.

[0008] Running strands can be designed as a rope, for example as a wire rope, fiber rope, hybrid rope, load strap, load belt or load chain.

[0009] While running ropes such as wire ropes are used primarily for cranes, load belts or load straps are used for passenger or freight elevators, for example. Load chains are used, for example, in locking devices such as locks or weirs.

[0010] A strand segment is a section of the at least one running strand that has a length of at least 0.20 mm, preferably 0.50 to 5.00 mm. The inventor has determined that a strand segment length between 0.5 mm and 5.00 mm results in a particularly precise method that, surprisingly, requires only a negligible additional computational effort, even for very long strands such as crane ropes, particularly when the method is designed as a computer-implemented method or simulation method. The sum of the lengths of all strand segments corresponds to a total length L of the at least one running strand.

[0011] The strand segments can also be several centimeters or several meters long. Although the strand segments can be of different sizes, in particular of different lengths, the strand segments are preferably of the same size.

[0012] According to Section 11 of the German VDI Guideline 2358 from 2012, the total operating time of a rope is defined as "the time between the laying of the rope and the achievement of one of the discard criteria specified in the standards," while the total service life is defined as "the time between the laying of the rope and the breakage of the rope." The total operating time is therefore the time the rope can be used reliably in the device, while the total service life is the time the rope can be used until failure. It is understood that the total operating time is shorter than the total service life. A rope is considered to be discarded if it must be replaced due to wear in order to continue to operate the device, especially a lifting device, safely (see, for example, ISO 4309 from August 2021).

[0013] The wear condition of a running train within the meaning of the present invention can be, for example, its remaining operating time or its remaining service life. The remaining operating time and the remaining service life are calculated from the total operating time specified for the running train or the total service life less any usage and load-dependent usage time already elapsed.

[0014] In particular, the remaining operating time or the remaining service life can be specified as the number of remaining bending cycles of the at least one running strand, on the basis of which it can be estimated how long the device can still be operated, i.e. how many bending cycles can still take place until the total operating time or the total service life is reached.

[0015] A wear parameter can be the so-called bending cycle rate, known to those skilled in the art. A bending of the at least one running strand by a strand guide causes a bending cycle, with a full bending cycle being a curvature from straight to bent to straight. A full bending cycle has a bending cycle rate of 1.0.

[0016] For example, a strand segment undergoes a full bending change when it is completely guided over a strand guide and is thus bent twice, once from straight to bent when entering the strand guide and a second time from bent to straight when leaving the strand guide.

[0017] A half bend cycle would be a single curvature from straight to bent or vice versa and would have a bend cycle count of 0.5.

[0018] Different types of bending cycles and their associated number of bending cycles are described in the VDI guideline 2358 from 2012, for example on page 12 (section Abbreviations).

[0019] Further wear parameters can be geometric parameters of the strand guide means of the device, geometric parameters of the at least one running strand, such as its diameter or design, and / or a force acting on the at least one strand, in particular a force acting in a longitudinal direction of the at least one strand. Parameters used are those that are relevant to wear and that can be easily determined using appropriate sensors such as weight or force sensors.

[0020] The construction of a wire rope, for example, is determined by the number of strands and the number of strand layers (see ISO 4309 from August 2021). The construction of a rope can also be referred to as a rope class (see, for example, DIN EN 12385-2 from 2008).

[0021] In addition, the groove size of a strand guide device such as a strand guide disk can have an influence on strand wear if, for example, the strand is squeezed into the groove under tensile stress and is thus subjected to transverse forces.

[0022] A diameter of the strand guide means, which determines a radius of curvature of the strand during its guidance, is also relevant to wear.

[0023] It is conceivable that further wear parameters are determined from the aforementioned wear parameters, for example so-called bending cycle factors, which in turn depend on a strand bending length and / or a strand diameter.

[0024] The wear parameters can be used to determine the wear condition of the running strand. Prediction models exist for this purpose, for example, those found in "Wire Ropes - Design, Operation, Safety" (Klaus Freyrer, 3rd edition, Vieweg Verlag, ISBN 978-3-642-54295-4) or ISO 4309 (version: August 2021).

[0025] It is understood that transferring the prediction models to other rope types, such as fiber ropes or hybrid ropes, poses no problems for the expert. Further prediction models are known, in particular, from "Estimating the Service Life of Running High-Modular Fiber Ropes" (Gregor Novak, dissertation; Reports from the Institute for Materials Handling and Logistics, University of Stuttgart; November 2017) and from "Contribution to the Investigation of the Service Life Behavior of Wire Ropes Under a Combined Tension, Bending, and Torsion Load" (Tobias Weber, dissertation; Reports from the Institute for Materials Handling and Logistics, University of Stuttgart; September 2013).

[0026] With regard to the definitions mentioned in the present application, reference is also made to the German VDI guideline 2358 from 2012, which is known to the person skilled in the art, as well as to the standards cited therein, in particular ISO 4309.

[0027] DE 10 2013 017 110 A1 discloses a method and device for determining the discard date of a fiber rope of an operating tower crane based on a change in the torsional stiffness of the fiber rope. This method is based on the knowledge that the torsional stiffness of a fiber rope increases with increasing load. If a limit value is exceeded, an acoustic or visual signal is displayed to the crane operator, indicating that the rope is ready for discard.

[0028] DE 10 2013 014 265 A1 discloses a device and method for determining the remaining service life of a fiber rope of a crane. The parameter used to determine the service life of the rope is a change in the flexural stiffness of the fiber rope.

[0029] CN 103112781 A describes a method for determining the service life of a wire rope used in a crane in real time based on a bending cycle distribution. Because each rope is only allowed to experience a certain number of alternating bending loads before reaching the point of wear, it is possible to determine in real time when the rope needs to be replaced. The disadvantage of this method is that the point of wear is determined solely based on the bending cycle distribution and other wear-relevant factors, in particular the weight of a moving load, are not taken into account. This makes the method known from CN 103112781 A very inaccurate. CN 103112781 A also does not consider the interactions between a lifting line and an adjustment line.

[0030] DE 20 2011 001 846 U1 describes a method and a device for determining the remaining service life of a fiber rope used in a crane. Several parameters are used for this purpose, in particular a so-called indicator profile, which can be embedded in the core of a strand or between fiber strands and which shows changes under load faster than the fiber ropes or fiber strands of the fiber rope. A detection device records several magnetic, mechanical, optical, and / or electronic rope parameters, such as the distance traveled or the elongation of a rope section. An evaluation unit uses these parameters to determine whether the fiber rope is ready for discard.

[0031] A method for determining wear on a winch cable of a snow groomer and for determining the remaining service life is known from DE 10 2011 080 466 A1. For this purpose, sensors record various cable parameters, sometimes indirectly based on the position of a winch arm or a GPS position of the snow groomer.

[0032] Methods for determining the wear condition of a wire rope are also known from DE 10 2004 063 709 B3, US 2017 / 045493 A1 and JP 2020 040801 A.

[0033] It is also known from the state of the art that the service life of a running rope can be estimated by assuming certain load cases. Since these assumptions are often inaccurate in practice, such a service life prediction, referred to as a static service life prediction, is inaccurate. The disadvantage is that frequent visual inspections are required.

[0034] The invention is based on the object of creating a method of the type mentioned at the outset by which a more precise determination of the wear condition of a running strand of a device, which may be a lifting or a closing device, is possible, in particular in real time.

[0035] According to the invention, the object is achieved in that adjacent strand segments of the at least one running strand with the same number of bending cycles are combined to form a strand section forming a strand segment group, and load classes are formed within each strand segment group, wherein strand segments with the same wear load, in particular strand segments guided via strand guide means of the same size and / or loaded with the same longitudinal force, form a load class.

[0036] The formation of strand segment groups advantageously creates an efficient process, as a separate wear condition does not need to be calculated for each strand segment, but only for strand segment groups. For example, if a running strand has 100 strand segments that can be combined into three strand segment groups, the wear condition needs to be determined three times instead of 100 times. In particular, the strand segments can be directly adjacent.

[0037] For a moving strand of a lifting device, for example, the relevant wear parameters for determining the remaining service life and / or remaining operating time include a longitudinal force acting on the strand or its strand segments, a number of bending cycles, and a diameter of a strand guide. The inclusion of other relevant wear parameters, such as the groove depth of a strand guide, is conceivable.

[0038] Strand segments with the same wear load are, in particular, those within a strand segment group that were subjected to the same longitudinal force and / or were guided over strand guides of the same size, particularly over those with the same diameter and groove depth. The use of other wear parameters, such as the strand guide groove depth, is conceivable.

[0039] By forming strand segment groups, computer-aided calculation effort for determining the wear condition can be significantly reduced.

[0040] By forming load classes within a strand segment group, a particularly accurate method is created, since not only a number of bending cycles is taken into account to determine the wear condition, but also other relevant wear parameters that act as corrections, reducing the remaining service life or remaining operating time for the same number of bending cycles.

[0041] If, for example, a strand segment is guided over a strand guide means with a diameter d 1 , its wear is higher for the same number of bending cycles than if it is guided over a strand guide means with a diameter d 2 , where d 1 < d 2 .

[0042] In particular, a wear condition of strand segments which experience fewer bending cycles than other strand segments but are subject to higher loads than these because the bending cycles are carried out by strand guide means which, for example, have a particularly small diameter, can be determined by a method according to the invention, so that a wear condition of the entire running strand can be determined particularly precisely.

[0043] It is advantageous and user-friendly if a remaining service life or remaining operating time is determined as a number of remaining bending cycles and displayed to the user. It is conceivable that the remaining service life or remaining operating time is displayed to the user of a lifting device as the number of remaining load strokes.

[0044] By forming string segment groups with load classes, it is also ensured that even in the case of large load position changes, an accurate determination of the remaining service life and remaining operating time of the running string is possible, since intermediate steps can also be recorded.

[0045] The load positions L i and L i+1 refer to a spatial arrangement of a load that is moved by the device from a first position L i to a subsequent position L i+1.

[0046] For example, if a lifting load is lifted by a crane by 10 m, this would be a change from a first load position L 1 , in which the lifting load is attached to a crane hook, to a load position L 2 , in which the lifting load is lifted by 10 m.

[0047] If the lock gates of a lock are opened, this would result in a change from a load position L 1 , i.e., a closed position of the lock gates, to a load position L 2 , i.e., an open position of the lock gates. A horizontal movement of the lock gates, for example, would cause wear on a moving chain that causes the opening.

[0048] A first strand segment may be the strand segment through which the running strand is connected to a strand guide means such as a rope drum, while a last strand segment may be the one that is connected, for example, to a load-handling device such as a crane hook.

[0049] Advantageously, at least one wear parameter, in particular a number of bending cycles and / or a longitudinal force acting on the strand segment, is determined for each of the strand segments, and from this a remaining service life and / or a remaining operating life is determined for each strand segment.

[0050] For running strands such as wire ropes for lifting devices, e.g. cranes, relevant wear parameters include a number of bending cycles, a longitudinal force acting on the rope, which is determined by the weight of a lifting load, and a diameter of strand guide means over which the running strand is guided.

[0051] By determining a remaining service life and / or a remaining operating life for each strand segment, a particularly accurate prediction method is preferably created. To this end, the inventor has recognized that the strand segment(s) with the shortest remaining service life or remaining operating life correspond to the remaining operating life or the remaining service life of the running strand. Only those strand segments need to be subjected to an inspection, such as a visual inspection, so that the inspection effort for a running strand is significantly reduced by the method according to the invention.

[0052] It is conceivable that a correction factor is calculated which reduces the operating time and / or remaining service life expressed as the number of remaining bending cycles. Such a correction factor, which is less than 1 and greater than zero, can be calculated, for example, when a running strand is used with loads of different weights, or when some strand segments of a running strand have the same number of bending cycles as other strand segments, but were guided over a strand guide that has a smaller diameter than that over which the other strand segments were guided. The higher the load or the smaller the strand guide diameter, the greater the wear of a running strand or the affected strand segments and the shorter the remaining operating time or remaining service life of the running strand.

[0053] With the method according to the invention, a wear condition can be determined for each change in a load position L i . Advantageously, a dynamic method is developed that takes into account the actual changes in load positions and thus enables a more precise determination of the wear condition, in contrast to methods known from the prior art.

[0054] The position of each strand segment of the at least one running strand is expediently determined based on a position of a strand guide means guiding the at least one running strand and / or a movement speed of a strand guide means guiding the at least one running strand when changing the load position L i to the subsequent load position L i+1.

[0055] For this purpose, a sensor device with which the device is provided and which comprises a sensor for determining a movement speed of a strand guide means can be used to determine a position of the strand segments when the load position L i changes to the subsequent load position L i+1 after defined time steps Δt at times tj by using known geometric parameters of the strand guide means and / or a rotational speed of the strand guide means.

[0056] For example, in a tower crane, the lifting distance by which a load is lifted is determined by the number of revolutions of a rope drum onto which a hoist rope carrying a hoist load is wound during lifting, as well as its diameter and other geometric parameters. This allows the position of each rope segment to be determined at any time tj during the change from the hoist load position L i to the subsequent hoist load position L i+1.

[0057] In one embodiment of the invention, a load class remaining lifetime and / or a load class remaining service life is determined for each load class, and from this a remaining lifetime and / or a remaining service life of the string segment group is determined.

[0058] Advantageously, it is possible to determine which load class significantly determines the remaining service life and / or remaining operating life of a group of strand segments. It is advantageous to correct a remaining service life and / or remaining operating life based solely on the determination of the number of bending cycles. This creates a particularly precise method in which the wear status can be clearly displayed to the user.

[0059] In a further embodiment of the invention, the wear condition of the at least one running strand in the load position L i+1 is determined starting from the load position L i. To determine the wear condition of the at least one running strand, only a change compared to an existing wear condition is considered. Advantageously, a particularly efficient method is developed.

[0060] For example, a wear condition in the load position L i can be the remaining number of bending cycles until the current strand reaches the so-called discard point. The remaining number of bending cycles until the discard point is reached in the load position L i+1 would be the number of bending cycles in the load position L i minus a number of bending cycles determined by wear during the change from the load position L i to the subsequent load position L i+1.

[0061] In a further embodiment of the invention, the wear state of the at least one running strand is determined based on a damage hypothesis for which a movement of the at least one running strand and a force acting on the at least one running strand during the change of the load position L i to the subsequent load position L i+1 are taken into account.

[0062] A damage hypothesis can be an equation that inputs values ​​from determined wear parameters and outputs a remaining service life or remaining operating time as a function of the wear parameters. Examples of damage hypotheses can be found, for example, in the aforementioned book by Klaus Feyrer, "Wire Ropes - Design, Operation, Safety," particularly in Chapter 3.4 - General Calculation Method for Rope Drives.

[0063] Depending on the application, more complex damage hypotheses may be used, which also consider the forces actually acting on the moving strand for each strand segment. These forces can be frictional forces between the strand and a strand guide, or transverse forces that occur due to the strand being guided by the strand guide. It is conceivable that by incorporating geometric parameters of the strand guide, such as its diameter or groove depth and / or width, correction factors can be determined that significantly determine the wear condition, meaning, in particular, that they reduce the remaining operating life and / or service life.

[0064] Advantageously, the wear condition of at least one running strand is continuously determined during operation of the device.

[0065] Advantageously, a person performing maintenance or inspection of the at least one running strand can concentrate on those strand sections that are particularly worn. Furthermore, a real-time method for determining the wear status of the at least one running strand is advantageously implemented.

[0066] In contrast to state-of-the-art static methods, which require assumptions about possible load positions to determine the remaining service life or remaining service life of a running train, continuous, real-time determination of the wear condition advantageously enables a more accurate service life or service life prediction, as well as the ability to identify train sections that are particularly worn. These can, for example, be subjected to additional, intensive visual inspection.

[0067] In one embodiment of the invention, for each running strand of a lifting device having a plurality of running strands, a wear condition of a lifting strand and / or an adjustment strand of the lifting device in the load position L i+1 is determined, preferably in such a way that interactions of the plurality of running strands are taken into account.

[0068] In a lifting device, a load position is a spatial arrangement of a lifting load.

[0069] One running strand can be a lifting strand, while another running strand can be an adjustment strand of the lifting device.

[0070] Currently known methods for determining the wear condition of at least one moving leg typically only concern the wear condition of the load leg, without considering wear experienced by the lifting leg due to movement of the adjustment leg. The adjustment leg is typically not considered in the prior art methods and is only subjected to a regular, time-consuming visual inspection during which the lifting device is not usable.

[0071] Interactions of strands occur, for example, when a strand guide means that guides a lifting strand changes its spatial position due to a first movement of an adjusting strand in such a way that the lifting strand experiences more bending cycles, for example due to a second movement, which can be a vertical lifting load movement, than without taking into account the first, horizontal movement of the strand guide means.

[0072] A wear condition of the lifting line in the load position L i+1 can be determined by superimposing wear conditions caused by the two movements, which can be considered independently of each other.

[0073] It is understood that more than two independent movements are conceivable.

[0074] Advantageously, a particularly accurate determination of the wear condition of the running strands of the lifting device is possible and thus a particularly reliable determination of a remaining service life and / or a remaining operating time after which a replacement of at least one strand must take place.

[0075] The method according to the invention is particularly advantageous for lifting devices which, for example, have several driven strand drums such as rope drums, for example tower cranes, luffing cranes, mobile cranes, crawler cranes or container loading cranes.

[0076] In a further embodiment of the invention, the method is designed as a computer-implemented method.

[0077] For this purpose, the computer can have a database in which positions of strand guide means, the changeable positions of the strand segments, as well as geometric parameters of the running strand used and the strand guide means are stored.

[0078] When changing the load position L i to the subsequent load position L i+1, the position change of each strand segment can be determined during the position change using the data stored in the database. Furthermore, a change in the spatial position of a strand guide device can be taken into account.

[0079] If, for example, a wear-relevant movement of one of the strand segments is detected during this position change, for example, via a strand guide, an entry is made in the database for this strand segment in a strand segment data record. For example, for winding a strand segment onto a drum, the strand segment data record can be supplemented with a bending cycle rate of 0.5.

[0080] For the strand segments or for strand sections that have strand segments with the same wear parameters, a wear condition is calculated, and an output signal is generated and output. For this purpose, various wear parameters and calculation methods for determining the wear condition, such as damage hypotheses, can be stored in the database based on the wear parameters.

[0081] It is understood that wear-relevant geometric parameters of one of the strand guide means that a strand segment has passed during the change of the load position L i to the subsequent load position L i+1 can supplement the strand segment data set.

[0082] It is also understood that strand segment groups and / or load classes can be formed and stored in the database, whereby a parameter of the strand segment data set is its affiliation to a strand segment group and / or a load class.

[0083] The output signal can be a remaining number of bending cycles until the end of service or strand failure, or a remaining number of load strokes. Conveniently, the at least one wear parameter and / or the wear state of the at least one running strand is displayed graphically over a length of the running strand on a display screen, preferably during or after each change from the load position L i to the subsequent load position L i+1 .

[0084] Such a graphical representation may be a diagram in which the at least one wear parameter and / or the wear state is displayed as a function of a strand position between 0 and a total length L of the running strand.

[0085] It is conceivable that a display is made as a function of the strand segments, with a first strand segment starting at position 0 and a last strand segment ending at position L (total length of the strand).

[0086] It is advantageous to enable real-time monitoring of the running strand, which also makes it easy to identify strand areas that are particularly stressed.

[0087] In one embodiment of the invention, a change in the at least one wear parameter and / or the wear state of the at least one running strand during the change of the load position L i to the subsequent load position L i+1 is continuously displayed graphically on a display screen over a length of the running strand.

[0088] Such a graphical representation can be a diagram that changes after each time step Δt, in which at least one wear parameter and / or the wear state is displayed as a function of a strand position between 0 and a total length L of the running strand. Δt is a time step after which a position determination of strand segments takes place during a change in the load position L i to L i+1.

[0089] Advantageously, wear can be tracked in real time while a load position is changing.

[0090] In a further embodiment of the invention, the method is designed as a simulation method in which a prediction of a wear state of a running strand is made when a load position L i of a moving load changes to a subsequent load position L i+1.

[0091] If a method according to the invention is implemented as a simulation method, a designer of a lifting or closing device can simulate various load cases and determine the wear condition of a running strand of the lifting or closing device. Based on the simulation results, it is conceivable that the design of the lifting or closing device can be modified in such a way that, under the same load cases, a longer remaining service life or a longer remaining service life of the running strand is achieved. For this purpose, strand guide means such as cable pulleys can be geometrically modified, or their spatial position within the lifting or closing device can be changed.

[0092] Advantageously, a method according to the invention designed as a simulation method makes it possible to design a lifting or closing device that is optimized for strand wear.

[0093] A device according to the invention, which is in particular a lifting device or a closing device, is characterized in that the device comprises at least one drive device for moving the at least one running strand and is designed to carry out a method according to the invention.

[0094] A drive device is provided for moving the at least one running strand and would, for example, in a crane, be a drum drive, i.e. a driven rope drum onto which a running hoist rope can be wound and unwound.

[0095] It is not necessary for the device itself to have an evaluation device such as a computer. It is conceivable that only sensor data from the device are collected and wirelessly transmitted to the evaluation device via a transmission device, wherein the evaluation device is configured to determine the wear condition, which can be a remaining service life and / or a remaining operating time of the at least one running strand.

[0096] Advantageously, sensor data from various operating devices can be stored and processed centrally. In particular, a database can be provided in which all sensor data is stored. It is conceivable that historical sensor data could be used to determine the wear condition of at least one running strand using new or previously unused prediction models or damage hypotheses. Advantageously, the method according to the invention can be adapted during continuous operation of the device in such a way that an even more precise determination of the wear condition is possible.

[0097] In one embodiment of the invention, the device has at least one adjustment line and / or at least one lifting line. Advantageously, it is possible to reliably determine the wear status of running lines even for complex devices with multiple lines, for example, for cranes such as tower cranes, container loading cranes, or other lifting devices.

[0098] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings relating to the exemplary embodiments. They show: Fig. 1A device according to the invention, which is designed as a lifting device, in five different lifting load positions L 1 to L 5 , Fig. 2A further device according to the invention, which is designed as a lifting device and which has a running adjustment cable, in two lifting load positions L 1 and L 2 , Fig. 3Method steps of a method according to the invention for determining a wear state of at least one running strand.

[0099] An embodiment of the method according to the invention according to Fig. 3 and a determination of a remaining lifetime and a remaining operating life is carried out in Fig. 1 and 2 shown embodiments, which show simple lifting devices.

[0100] One in Fig. 1The schematically shown lifting device 1, designed as a crane, comprises a running hoist rope 2 with a total length L, which is deflected via a rotatable pulley 3, with a wrap angle of 90 degrees. This means that the hoist rope 2 is deflected by 90 degrees by the pulley 3. In this embodiment, the running hoist rope 2 is designed as a twisted wire rope.

Claims

1. Method for determining a state of wear, in particular for predicting a remaining service life and / or a remaining operating time, of at least one running strand (2; 2a, 18) of an apparatus (1; 1a) using the at least one running strand for its intended use, in which, during operation of the apparatus, a position of strand segments (12; 12a, 23) of the at least one running strand (2; 2a, 18) is determined, wherein at least one wear parameter is determined for each strand segment (12; 12a, 23) of the at least one running strand (2; 2a, 18) when a load position Li of a load (6, 9; 6a) moved by the apparatus (1; 1a) is changed to a subsequent load position Li+1, from which wear parameter the state of wear of the at least one running strand (2; 2a, 18) is determined, characterized in that adjacent strand segments (12; 12a, 23) of the at least one running strand (2; 2a, 18) with the same number of bending cycles are combined to form a strand section (13-17; 13a, 14a, 15a) forming a strand segment group (S1-S5), and load classes (K1, K2) are formed within each strand segment group (S1-S5), wherein strand segments (12; 12a, 23) with the same wear characteristics, in particular strand segments guided by strand guiding means of the same size and / or loaded with the same longitudinal force, form a load class (K1, K2).

2. Method according to claim 1, characterized in that for each of the strand segments (12; 12a, 23) the at least one wear parameter, in particular a number of bending cycles and / or a longitudinal force acting on the strand segment, is determined, and a remaining service life and / or a remaining operating time is determined therefrom for each strand segment (12; 12a, 23).

3. Method according to claim 2, characterized in that a load class residual service life and / or a load class residual operating time is determined for each load class (K1, K2), and a residual service life and / or a residual operating time of the strand segment group (S1-S5) is determined therefrom.

4. Method according to claim 3, characterized in that the remaining service life and / or the remaining operating time of the running strand (2; 2a, 18) is determined on the basis of a remaining service life and / or a remaining operating time of that strand segment group (S1-S5) with the lowest remaining strand segment service life and / or the lowest remaining strand segment operating time.

5. Method according to any one of claims 1 to 4, characterized in that the state of wear of the at least one running strand (2; 2a, 18) is determined on the basis of a damage hypothesis, for which a movement of the at least one running strand (2; 2a, 18) and a force acting on the at least one running strand are taken into account when the load position Li is changed to the subsequent load position Li+1.

6. Method according to any one of claims 1 to 5, characterized in that for each running strand (2a, 18) of a hoisting apparatus (1a) having a plurality of running strands (2a, 18), a wear state of a hoisting strand (2a) and / or of an adjusting strand (18) of the hoisting apparatus (1a) is determined in the load position Li+1, preferably in such a way that interactions of the plurality of running strands (2a, 18) are taken into account.

7. Method according to any one of claims 1 to 6, characterized in that the method is designed as a computer-implemented method.

8. Method according to any one of claims 1 to 7, characterized in that the at least one wear parameter and / or the state of wear of the at least one running strand (2; 2a, 18) is displayed graphically over a length of the running strand on a dis play screen, preferably during or after each change of the load position Li to the subsequent load position Li+1.

9. Method according to any one of claims 1 to 8, characterized in that a change in the at least one wear parameter and / or the state of wear of the at least one running strand (2; 2a, 18) during the change of the load position Li to the subsequent load position Li+1 is displayed graphically continuously on a display screen over a length of the running strand.

10. Method according to any one of claims 1 to 9, characterized in the method is designed as a simulation method in which a prediction of a state of wear of a running strand is carried out during or after the change of the load position Li of a moving load (6, 9; 6a) to the subsequent load position Li+1.

11. Apparatus, in particular hoisting apparatus (1; 1a) or closing apparatus, which has at least one running strand (2; 2a, 18), a strand guiding means (3, 5; 3a, 5a, 21, 22) for the at least one running strand (2; 2a, 18) and a sensor device comprising at least one sensor (10, 11; 10a, 11a, 24) for detecting a speed of movement of the strand guiding means and / or for detecting a force acting on the at least one strand, characterized in that the apparatus (1; 1a) comprises at least one driving device (5; 5a, 22) for moving the at least one running strand (2; 2a, 18) and is designed to carry out the method according to one of claims 1 to 9.

12. The apparatus according to claim 11, characterized in that the apparatus (1; 1a) has at least one adjusting strand (18) and / or at least one hoisting strand (2; 2a).