DE102008026731A1 - Method for determining wear state of oblong tension or power transmission unit, involves detecting change of length or expansion of wave guide, where wave guide is integrated at or in tension or power transmission unit - Google Patents

Abstract

The method involves detecting a change of the length or an expansion of a wave guide (3), where the wave guide is integrated at or in a tension or power transmission unit (1) with a signal reflected end over the length of the tension or power transmission unit. The impulse (10) is transferred on the basis of a switching circuit (7) over the wave guide, in which the switching circuit is returned. The change in length or expansion of the wave guide is determined from a change of an impulse transit time by the wave guide. The wave guide is a light wave guide made of glass or plastic. An independent claim is included for a device for determining a wear state of an oblong tension or power transmission unit.

Description

The The present invention relates to a method and an apparatus for determining a state of wear of an oblong, at least partially formed from fibers traction or power transmission means, in particular a rope or a belt.

When Traction or power transmission means, for example high strength synthetic fiber ropes are used. They reach partly higher strength than steel cables, at much lower Weight. So far, no method and no device are known to the state of wear of such a traction means made of synthetic fibers to determine metrologically.

From the German patent application DE 10 2005 057 055 A1 For example, a method and apparatus for detecting mechanical stresses on a pipeline is known. In the method, a change in length and / or a length of laid in or on the pipeline, associated with this waveguide is determined. For this purpose, a periodic input signal is coupled into the waveguide, coupled out a periodic output signal from the waveguide, the input signal and the output signal applied to a phase comparison circuit for generating a phase difference signal, the input frequency of the input signal changed until generating a constant phase difference signal and monitors the constant phase difference signal or a changing phase difference signal is signaled.

According to the known technical methods are thus two periodic signals in the frequency domain with respect to their phase shift to each other rated. Since the determined phase difference is not one-to-one Provides information about the length of the waveguide, the measurement must be carried out at at least two different frequencies. To a signal generator is needed whose periodic Output signal in the frequency can be varied. This form the measurement requires a large metrological Effort, whereby the measurement technique used is not compact enough can be designed, has high energy consumption and is expensive.

Further are in the art systems for building monitoring described using a strain measurement based on fiber Bragg gratings. In the known method is for determining a change in length or elongation a specially manipulated optical fiber needed. For electrical conductors, this method is not applicable. Furthermore, the total length of the sensor fiber through Evaluation of the so-called Bragg wavelength or their Displacement can not be determined. In addition, such need Systems for temperature compensation a second, mechanically unloaded Fiber. Due to the principle, Bragg grating sensors are sensitive to Bends of the sensor fiber. For use in textile Pulling means, such as fiber ropes, these are therefore unsuitable.

It is therefore the object of the present invention, a method and a device for determining a state of wear an elongated, at least partially made of fibers tensile train or to provide power transmission means, which with low device-side and metrological effort Reliable statements about the state of wear allow the traction or power transmission means, wherein In addition, the device field suitable and compact is and has a low energy requirement over long periods.

The Task is on the one hand by a method of the above type solved, with a change of a length or an elongation of at least one waveguide which is loop-shaped and double or simply stretched with a signal-reflecting End over the length of the traction or power transmission means integrated on or in the traction or power transmission means is detected by the fact that individual impulses starting from at least transmitted to a circuit via the waveguide, returned to the at least one circuit and from a change in a pulse transit time the waveguide the change in length or elongation of the waveguide is determined.

According to the invention a single waveguide to a respective state of wear of the To determine tensile or power transmission means. To have to thus no reference fibers, such as Bragg gratings such as in the prior art. Thus, a simple and inexpensive device for determining the state of wear of the traction or power transmission means available be put.

Becomes a waveguide with a measuring signal reflecting end stretched over the length of the traction or power transmission means used, the back and forth signal with Help of an optical or electrical directional coupler after on the Sensor fiber of the waveguide running transmitting and returning Split receive pulses and the timing supplied become.

In addition, the measuring method according to the invention, in which it is sufficient for a single pulse from the circuit via the waveguide to the circuit requires return, no expensive and therefore expensive measurement technology. Rather, the wear measuring device can be designed inexpensively, field suitable and compact.

The inventive method works completely in the time domain. There are neither periodic signals nor a frequency changeable Signal generator needed. This makes it possible the component cost and thereby the dimensions of the used Sensor electronics to a minimum. Due to the principle and by using temporally very short individual pulses as a measurement signal The invention enables a determination of the length or the change in length of the waveguide within a very short time interval. This makes this procedure special energy-saving and for autonomous, battery-powered Operation suitable.

In an advantageous embodiment of the present invention is in addition to the change in length or stretching at least one mechanical load of the tensile or Force transmission means detected and determined with the Length change or elongation evaluated. By the additional measurement of the actual load of the train or power transmission means may be a stress-strain diagram to be created. Of the thus real-time recoverable data Conclusions about the state of wear or the Ablegereife of the traction or power transmission means to be pulled.

In A preferred variant of the present invention is at a the sensor electronics associated with the waveguide detects a temperature. This allows a correction of the temperature-dependent Signal propagation time within the waveguide or within the transducer or lying in the signal path electronic components of the circuit.

It is particularly favorable if the measured and / or determined Transfer values wirelessly to a monitoring system become. Thus, a wireless data exchange to parent Systems take place where the measured and / or determined values can be displayed or further processed.

According to one preferred example of the present invention is at a fixed impermissible change in length or elongation of the traction or power transmission means and / or on reaching a specified impermissible temperature range Signal or warning signal issued. This allows the train or power transmission means in time exchanged before a potential danger or if necessary be repaired, or it can be prevented in time the traction or power transmission means with further high loads is charged.

In a particularly favorable embodiment In the present invention, multiple measurements of the pulse transit time conducted in quick succession and using statistical methods an average value of the pulse transit time is determined. This will increase the accuracy the measurement is improved by fluctuations in the measured value, if necessary occurring signal jitter can be compensated.

The Object is further by a device of the above type dissolved, wherein on or in the traction or power transmission means at least one waveguide looped and double or simply stretched with a signal-reflective end over the length of the traction or power transmission means is integrated and one or both ends of the waveguide with at least a circuit with elements for single pulse generation and pulse transit time measurement are connected.

The Device according to the invention allows An online monitoring of elongated, at least Partially made of fibers tensile or power transmission means. Since elements for single pulse generation and pulse transit time measurement are provided, which are both integrated in a circuit as may also be separate assemblies of an electronics, can the measurement of the state of wear of the train or Power transmission means in a simple manner by means of a single pulse coming from the circuit via the waveguide is returned to the circuit done. Accordingly, the required measurement technique is low and therefore can be made compact. Because that can be realized with the circuit Measuring principle only each short-term energy needed, can In addition, the device according to the invention in addition to the general network operation also in battery mode be used. Thus, the invention is suitable Device especially for field use.

It has proven to be particularly favorable when the train or power transmission means is a synthetic fiber rope. at such synthetic fiber ropes, it has not been possible during use a suitable provision of the to carry out respective wear condition. Become synthetic fiber ropes However, in practice as a tensile or power transmission means always interesting, because they have very high strengths.

In a further advantageous embodiment of the present invention, the waveguide is a fiber-shaped optical waveguide made of glass or plastic or a twisted wire-shaped electrical conductor. Thus, both optical and electrical measuring principles according to the invention be used. Depending on the field of application, an optical waveguide made of glass or plastic or an electrical waveguide, such as, for example, a twisted pair cable, can be used. If, for example, optical waveguides made of glass or plastic are used as waveguides, their permissible elongation lies in the same order of magnitude as the working strain of tensile or force transmission means of high-strength synthetic fibers. Accordingly, the optical waveguides used can be adapted suitably to the permissible strains in the tension or force transmission means whose wear state is to be determined, wherein the mechanical stresses in the traction or power transmission means do not lead to the destruction of the waveguide.

In a particularly favorable embodiment According to the present invention, the waveguide is between a supporting one Core of the traction or power transmission means and a the Nuclear surrounding, more stretchable jacket provided. Consequently The waveguide can be suitably fixed to the waveguide. Since the jacket is more elastic than the core and the waveguide or has a lower rigidity than the core and the waveguide is the waveguide at a high, the traction or power transmission means acting tensile force is not destroyed.

It has proven to be particularly favorable when the coat is formed of a braid. A braided coat possesses the advantageous property that it is at a tensile load contracting and thus increasing the stiction between the waveguide and the core of the traction or power transmission means causes. Is the stiction large enough, leaving a traction can be transferred to the waveguide, which is the elongation of the Waveguide causes a slip-free connection between Waveguide and rope structure can be realized.

In a preferred embodiment of the present invention is the Braided braided jacket. Thus, the waveguide can be simple be fixed between jacket and core. There is an adjustment the stiction between core, waveguide and cladding, so that the necessary to stretch the waveguide tensile force transmitted can be.

For example the jacket is made of polyester. This material is suitable especially to form a sheath braid with slight preload.

According to one Embodiment of the present invention may be the core be braided n-fold or be formed of parallel fibers. This can provide a high-strength core available with which high forces can be absorbed, so that the respective state of wear by means of the waveguide on long operating times of the traction or power transmission means can be determined reliably.

It is particularly advantageous if the device is a temperature sensor having. The temperature sensor may optionally be in a signal converter be integrated in the circuit or close to the circuit Signal converter of the circuit can be provided. The temperature sensor allows a correction of the temperature-dependent Signal propagation time within the converter or lying in the signal path electronic assemblies.

According to one Another embodiment of the invention, it is advantageous if the Circuit a timer and a non-volatile memory having. An additional timer circuit, preferably with date function, allows in conjunction with the non-volatile Memory that integrates into a microcontroller or as a stand-alone Circuit may be formed, creating a "burden past" of the Traction or power transmission means. For this individual Signature of the traction or power transmission means can Device according to the invention optionally automatically a current state of wear or a replacement time if the time-off of the monitored train or force transmission means determine or signal.

In a further preferred embodiment of the present invention Invention comprises the traction or power transmission means both ends of the waveguide connecting, loop-like end connector on, wherein the circuit within the loop-type end connector is provided. Thus, the circuit can suitably not disturbing position at the traction or power transmission means in direct connection be brought with the waveguide.

In a favorable development of the present invention are more on or in the train or power transmission means Waveguide loops or multiple elongated waveguides and at least a switch for the waveguide provided. Thus, you can different areas of the traction or power transmission means may be monitored separately or it may be due to use redundant waveguide higher reliability be provided to the monitoring.

In a further embodiment of the present invention the circuit has a temperature compensated crystal as reference for the timekeeping up. Thus, the accuracy of the Pulse transit time measurement can be increased.

advantageous Embodiments of the present invention, their structure and function will be described below with reference to the figures of the drawing explains

1 schematically shows a possible embodiment of the device according to the invention for determining a state of wear of a traction or power transmission means based on a general principle of operation;

2 schematically shows integration of a waveguide in a traction or power transmission means according to an embodiment of the present invention;

3 schematically shows a sectional view through a traction or force transmission means with a waveguide integrated therein or therein, wherein in the embodiment shown, the waveguide between a high-strength core and a sheath braid is provided; and

4 schematically shows an embodiment of the device of the present invention, wherein the circuit is provided within a loop-like end connector to the train or force transmission means to be monitored.

1 schematically shows an embodiment of the inventive device for determining a state of wear of an elongated, at least partially made of fibers 2 trained traction or power transmission means 1 based on a general principle of operation. In the in 1 The example shown is the traction or power transmission means 1 a rope made of high-strength synthetic fibers, which, as in 1 indicated, n-fold braided or, as in 2 indicated as parallel fibers 2 can be provided.

In other embodiments of the present invention, as a traction or power transmission means 1 whose wear is determined by the device according to the invention, a belt or toothed belt can be used. Thus, both fixed position as well as moving traction or power transmission means can be monitored by means of the device according to the invention.

In or on the traction or power transmission means 1 a waveguide is integrated. In the example of 1 is as a waveguide 3 an optical waveguide provided. The optical fiber is a sensor fiber made of glass or plastic. In other embodiments of the present invention may also be a waveguide 4 be used in the form of an electrical conductor. For example, the use of a twisted pair cable is suitable for this purpose. Whether an optical waveguide or an electrical waveguide is used as waveguide can be freely determined depending on the particular field of application of the device according to the invention.

The waveguide 3 , or in other embodiments of the waveguide 4 , has a length l and extends in a loop and twice over the length L of the traction or power transmission means 1 , Both ends 5 . 6 of the waveguide 3 are with a circuit 7 connected. A first end 5 of the waveguide 3 is with a signal converter 18 connected and a second end 6 of the waveguide 3 is with a signal converter 19 connected.

In other, not shown embodiments of the present invention, it is also possible, the waveguide 3 or 4 stretched, so not in the form of a conductor loop in the train or power transmission means 1 contribute. In this embodiment are at the end of the waveguide 3 . 4 To make arrangements that the transmitted pulse signal can be reflected back. For example, this can be done at the coupling point or connection point of the waveguide 3 . 4 So-called directional coupler can be used. This additional element, which can operate both optically and electrically, makes it possible to separate the signal path in the transmitting and receiving direction, wherein the propagating pulse 10 or the transmit pulse on the same sensor fiber of the waveguide 3 . 4 is transmitted as the returning, finally reflected receive pulse.

Moreover, according to a further preferred embodiment of the invention, it is possible that on or in the traction or power transmission means 1 a plurality of waveguide loops or a plurality of elongated waveguides and at least one switch with sensor electronics for switching the waveguides 3 . 4 are provided.

The signal converter 18 obtained by a pulse generator 8th at least a single pulse 10 passing through the waveguide 3 is transmitted and via the signal converter 19 in the circuit 7 is returned. Occurs at the train or power transmission means 1 a change in the length L or an elongation of the traction or power transmission means 1 on, the length l of the waveguide also changes 3 , which causes a change in the pulse transit time t through the waveguide 3 results. The change Δt is in the circuit 7 through a time measuring unit 9 detected. The accuracy of the time measurement can be increased when the circuit 7 a temperature-compensated quartz as a timing reference has.

In addition, it may be favorable if several measurements of the pulse transit time t are carried out in quick succession and statistical methods for Determination of the signal propagation time can be used. This improves the accuracy of the measurement of the pulse transit time by compensating for measured value fluctuations by signal jitter that may occur.

The time measuring unit 9 and the pulse generator 8th are directly with a control unit or a microcontroller 20 coupled to a non-volatile memory 16 as well as a measured value and signal output.

The control unit 20 is again with a standard measuring system 21 for determining a tensile force on the traction or power transmission means 1 , a temperature sensor 14 and a timer 15 coupled. The temperature sensor 14 may also be in one of the signal converter 18 . 19 or directly on the traction or power transmission means 1 or the waveguide 3 be integrated.

The timer 15 can also have an electronic calendar.

The device after 1 works as follows: With the help of the integrated circuit 7 or the pulse generator contained therein 8th become single short electrical impulses 10 generated. These are via the signal converter 18 directly into the waveguide 3 transmitted and via the signal converter 19 to the circuit 7 recycled. The time measuring unit 9 of the circuit 7 now determines a time span between the transmission and the reception of the pulse 10 , The time difference .DELTA.t is sent to the control unit or the microcontroller 20 transfer. This is calculated on the basis of the knowledge of the electrical or optical properties of the waveguide 3 and the electrical characteristics of the signal transducers 18 . 19 the length of the waveguide 3 ,

The with the control unit 20 coupled and near the signal converter 18 . 19 provided or directly integrated temperature sensor 14 allows a correction of the temperature-dependent signal propagation time t within the signature converter 18 . 19 , the waveguide 3 as well as further in the signal path lying electronic assemblies.

With the standard measuring system 21 In addition, a tensile force or tensile stress on or in the traction or power transmission means 1 certainly. From this can by the circuit 7 or a parent monitoring system 11 Stress-strain diagrams or partial areas can be determined from this.

The timer 15 , which may additionally have a date function, allows in connection with the non-volatile memory 16 which is both in the control unit 20 integrated or formed as a separate circuit, the creation of a "burden history" of the traction or power transmission means 1 , From this individual signature of the traction or power transmission means 1 The device according to the invention may optionally automatically a current state of wear or a tauschzeitpunkt on reaching the Ablegereife of the traction or power transmission means 1 determine or signal.

All components used in the device according to the invention, with the exception of the optical converter 18 . 19 , have a low energy requirement. The increased power consumption of optical converters 18 . 19 , which only when using optical fibers 3 As a sensor fiber can be reduced by short turn-on. The measuring device according to the invention is therefore particularly well suited for battery operation.

The control unit or the microcontroller 20 allows a data exchange to higher-level systems, such as the monitoring system schematically illustrated here 11 , Depending on the application, the data exchange can be wired or wireless.

The electronic components of the circuit 7 can be made so compact that they, as it is in 1 or in 4 is shown, directly on the traction or power transmission means 1 can be attached.

2 schematically shows an embodiment of a traction or power transmission means 1 at which its wear state can be determined with the device according to the invention. The traction or power transmission means 1 is in the in 2 example shown a rope made of high-strength synthetic fibers 2 which is a bearing core 12 of the traction or power transmission means 1 form. To the core 12 is a coat 13 provided that stronger than the core 12 is stretchable. Between the supporting core 12 and the core 12 surrounding coat 13 is the waveguide 3 provided, which in the in 2 example shown is an optical waveguide made of glass or plastic. In other embodiments of the arrangement 2 may instead of the waveguide 3 also an electrical waveguide 4 be provided in the form of a twisted pair cable, which may be shielded or unshielded.

The principle 2 is schematically based on 3 clarified in more detail. So shows 3 schematically in a sectional side view of a section of the traction or power transmission means 1 with the high-strength core 12 , the coat 13 and the intermediate core 12 and coat 13 looped and double over the length L of the traction or power transmission means 1 provided waveguide 3 ,

In the in 3 the example shown consists of the jacket 13 from a network. The coat 13 is more elastic than the core 12 and the waveguide 3 or has a lower rigidity than the core 12 and the waveguide 3 on. This allows the sensor fiber of the waveguide 3 not permanently or immediately by an increased tensile force on the traction or power transmission means 1 gets destroyed.

The coat braid of the coat 13 is braided with slight pretension and consists in the in 3 shown example of polyester. In this way, the sensor fiber of the waveguide 3 between the coat 13 and the core 12 be fixed, that is, there is an adaptation of the static friction between the core 12 , the waveguide 3 and the coat 13 , so that the stretching of the waveguide 3 necessary traction can be transmitted. There is thus an almost slip-free connection between the waveguide 3 and the cable structure of the traction or power transmission means 1 ,

The mechanical stresses in the traction or power transmission means 1 can reach very high values that exceed the allowable forced voltages of the waveguide 3 exceed. If an arrangement according to 2 or 3 used, may be a kinking of the sensor fiber of the waveguide 3 at the entry or exit point from the traction or power transmission means 1 be prevented. This is achieved here by the sensor fiber of the waveguide 3 between the carrying rope core 12 and the surrounding, more stretchy coat braid of the coat 13 is introduced. In the area of the sensor fiber of the waveguide 3 As a result, the resulting forced voltages are significantly lower. Accordingly, a buckling of the sensor fiber of the waveguide 3 prevented in this way. The frictional connection between the cable structure and the sensor fiber of the waveguide 3 can still be made large enough to almost slip-free transmission of rope elongation of the traction or power transmission means 1 on the sensor fiber of the waveguide 3 to ensure.

4 schematically shows a variant of the device according to the invention for determining a state of wear of a traction or power transmission means 1 in the form of a high-strength synthetic fiber rope. In the example shown is at one end of the traction or power transmission means 1 one both ends 5 . 6 of the waveguide 3 connecting, loop-type end connector 17 intended. Within the loop 22 of the end connector 17 is the circuit 7 housed, with the sensor electronics of the circuit 7 directly with the ends 5 . 6 of the waveguide 3 connected is. At the in 4 embodiment shown is the waveguide 3 an optical fiber, but may also be an electrical waveguide in other embodiments of the present invention 4 be.

The inventive device, which, for example, schematically in the 1 to 4 is shown, can be used in a variety of applications. For example, the device according to the invention is suitable for structural monitoring or for bridge construction, where, for example, cable-stayed bridges are used, in which monitoring of the length of the suspension cables is necessary. In the construction supervision or in bridge construction, the device according to the invention is a good alternative to the Bragg sensors described in the prior art. In contrast to the applications with Bragg sensors, however, the device according to the invention has a simpler structure. Furthermore, no specially doped fibers with lattices provided therein, as described in the prior art, according to the invention are necessary. Since glass and also plastic optical waveguides have a permissible elongation which is of the same order of magnitude as the working strain of high-strength synthetic ropes, these can be used particularly advantageously in the device according to the invention. In particular plastic optical waveguides are preferably used, since even greater strains than with glass optical waveguides can be measured with such optical waveguides.

Further the device according to the invention is suitable for a mission in aircraft towing. Critical here is a break in the Rope breaking point due to excessive load during towing shortly after the start at low altitudes. Will the here used according to the invention, can be issued a warning before breaking the breaking point, that the pull rope lengthens more than predefined, which a sign of excessive traction. Thereupon can the sluggish pilot slightly reduces the traction. The breaking point stays intact. Accordingly, a dangerous flight situation can be avoided become.

The device according to the invention can also be used particularly favorably at high elevators. For very long or high elevators, z. As in skyscrapers, conventional lifts with steel cables are limited in length according to the number of floors to be operated. If the steel cables are too long, they already tear because of their high weight. This problem can be solved by using high-strength synthetic fiber ropes. These bear higher loads than steel cables and are also much lighter. However, most plastics tend more or less to crawl, that is, they are under constant stress getting longer and thinner. Therefore, if the state of wear measuring device according to the invention is used, this elongation of the supporting cables can be measured and warnings can be issued based on predefined criteria.

Another possible application of the device according to the invention for determining a state of wear of a traction or power transmission means 1 is the crane building. Here, too, high-strength synthetic fiber ropes are of interest, since large cranes can cause unintentional center of gravity shifts due to the high mass of steel cables. The inventively proposed device can be used here for monitoring the rope length. A rope that has become severely elongated would tear at a lower load due to the tendency to creep, even if it seems otherwise completely intact, as it has become thinner and thus has a smaller load-bearing cable cross-section.

Either in elevator and crane construction is a measurement of the load with the aid of the device according to the invention A detection of the elongation also measurable. Because with big loads For example, load cells are very expensive, the measurement of Stress on the detection of an elongation the advantage that it can be cheaper from an economic point of view.

A further application of the invention Device is the online monitoring of belts or Toothed belt. Since here the possibility of a contactless Energy supply and measured value output is, is suitable Thus, the device according to the invention also for use on moving traction or power transmission means.

Consequently has the device according to the invention and the Measuring method according to the invention has the advantage that generally an online monitoring of traction or power transmission means, in particular ropes or belts of high-strength synthetic fibers, realizable is. It can be both short and long distances of traction or power transmission means with the aid of plastic or glass fiber optic cables are monitored. It is both a mains and a battery operation possible. Further can be warned against critical load conditions according to the invention become. In addition, due to the "history" of the Traction or power transmission means a current state of wear as well as the Ablegereife of the traction or power transmission means be derived.

According to the invention by means of the in the tensile or power transmission means 1 integrated waveguide, the length or change in length of the traction or power transmission means 1 be determined. By additional measurement of the acting tensile loads, the stress-strain behavior can be determined and based on the respective tensile or force transmission means 1 criteria to be determined the state of wear of the traction or power transmission means 1 be determined. The inventive method is inherently insensitive to a disturbing influence of bends of the traction or power transmission means 1 on the measured variable.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• - DE 102005057055 A1 [0003]

Claims (20)

Method for determining a state of wear of an elongated, at least partially made of fibers ( 2 ) trained traction or power transmission means ( 1 ), characterized in that a change of a length (l) or an elongation of at least one waveguide ( 3 . 4 ) which is looped and double or simply stretched with a signal reflecting end over the length (L) of the traction or power transmission means ( 1 ) on or in the traction or power transmission means ( 1 ) is detected by detecting individual pulses ( 10 ) starting from at least one circuit ( 7 ) over the waveguide ( 3 . 4 ), in the at least one circuit ( 7 ) and from a change of a pulse transit time (t) through the waveguide ( 3 . 4 ) the change in length or elongation of the waveguide ( 3 . 4 ) is determined. A method according to claim 1, characterized in that in addition to the change in length or elongation at least one mechanical load of the traction or power transmission means ( 1 ) is detected and evaluated with the determined change in length or elongation. A method according to claim 1, characterized in that from the detected change in length or elongation at a known stress-strain behavior of the traction or power transmission means ( 1 ) a mechanical load of the traction or power transmission means ( 1 ) is determined. Method according to one of the preceding claims, characterized in that on one of the waveguides ( 3 . 4 ) associated electronics a temperature (T) is detected. Method according to one of the preceding claims, characterized in that the measured and / or determined values are transmitted wirelessly to a monitoring system ( 11 ) be transmitted. Method according to one of the preceding claims, characterized in that at a specified impermissible change in length or elongation of the traction or power transmission means ( 1 ) and / or reaching a specified impermissible temperature range a message or warning signal is issued. Method according to one of the preceding claims, characterized in that several measurements of the pulse transit time (t) be carried out in quick succession and an average the pulse transit time (t) is determined. Device for determining a state of wear of an elongated, at least partially made of fibers ( 2 ) trained traction or power transmission means ( 1 ), characterized in that on or in the traction or power transmission means ( 1 ) at least one waveguide ( 3 . 4 ) looped and double or simply stretched with a signal reflecting end over the length (L) of the traction or power transmission means ( 1 ) and one or both ends ( 5 . 6 ) of the waveguide ( 3 . 4 ) with at least one circuit ( 7 ) with elements for single pulse generation ( 8th ) and pulse transit time measurement ( 9 ) are connected. Apparatus according to claim 8, characterized in that the traction or power transmission means ( 1 ) is a synthetic fiber rope. Device according to claim 8 or 9, characterized in that the waveguide ( 3 . 4 ) a fiber-shaped optical waveguide ( 3 glass or plastic or a twisted, wire-shaped electrical conductor ( 4 ). Device according to one of claims 8 to 10, characterized in that the waveguide ( 3 . 4 ) between a supporting core ( 12 ) of the traction or power transmission means ( 1 ) and one the core ( 12 ) surrounding, more extensible jacket ( 13 ) is provided. Device according to claim 11, characterized in that the jacket ( 13 ) is formed of a mesh. Device according to claim 12, characterized in that the jacket ( 13 ) is braided with bias. Device according to one of claims 11 to 13, characterized in that the jacket ( 13 ) is formed of polyester. Device according to one of claims 11 to 14, characterized in that the core ( 12 ) n-fold or from parallel fibers ( 2 ) is trained. Device according to one of claims 8 to 15, characterized in that the device is a temperature sensor ( 14 ) having. Device according to one of claims 8 to 16, characterized in that the circuit ( 7 ) a timer ( 15 ) and a non-volatile memory ( 16 ) having. Device according to one of claims 8 to 17, characterized in that the traction or power transmission means ( 1 ) one or both ends ( 5 . 6 ) of the waveguide ( 3 . 4 ) connecting, loop-like end connector ( 17 ), wherein the circuit ( 7 ) within the loop-type end connector ( 17 ) is provided. Device according to one of claims 8 to 18, characterized in that on or in the traction or power transmission means ( 1 ) a plurality of waveguide loops or a plurality of elongated waveguides and at least one switch for the waveguide are provided. Device according to one of claims 8 to 19, characterized in that the circuit ( 7 ) has a temperature compensated crystal as a reference for the time measurement.