BELT, DEVICE AND SYSTEM

Description

[0001] The invention relates to a belt, a device and a system.

[0002] Belts are generally known from the prior art. A belt is preferably a drive belt for transmitting tensile forces. The service life of a belt is at least partly determined by the elongation of the belt, in particular the elongation in a circumferential direction. Elongation of a belt usually occurs repeatedly during the corresponding revolutions of the belt. A belt is often exposed to pretension, useful forces, centrifugal forces and / or bending. A belt is often used in such a way that the belt partially wraps around at least two pulleys so that the belt can be driven in a rotating manner. The rotational speed at which the belt moves and / or the power required to drive the belt can provide information about the load on the belt. However, this load can only provide a rough estimate of the actual local elongation of the belt.An exact determination based on the previously mentioned load is not possible.

[0003] Strain gauges are known from the prior art. However, the use of a strain gauge requires an electrical measuring circuit that is coupled to the strain gauge in order to evaluate the strain detected by the strain gauge or to provide a corresponding evaluation signal. Therefore, using a strain gauge for a belt also requires the aforementioned evaluation circuit. Particularly if the belt is exposed to high temperatures during use, which are influenced, for example, by friction between the belt and a pulley and / or by a high ambient temperature, a correspondingly robust evaluation circuit can only be manufactured with considerable technical effort and correspondingly high costs.

[0004] US 2009 / 178902 A1 describes a belt monitoring system that uses a belt with at least one reinforcement element made of a conductive reinforcement material. A belt monitoring device is arranged in connection with the belt. The belt monitoring device includes a field inductor that is excited by an applied signal. An electrical characteristic of at least a portion of the field inductor, which is influenced by changes in the electrical properties of the conductive reinforcement element, is monitored to determine a physical condition of the conductive reinforcement element and thereby monitor a physical property of the belt. This monitoring can be performed by a measuring inductor arranged adjacent to or in connection with the field inductor.

[0005] The invention is therefore based on the object of providing a belt, a device and / or a system with which a robust detection of the stretching of a belt - even during operation - can be ensured or at least supported.

[0006] According to a first aspect of the invention, the object is achieved by a belt having the features of claim 1. Thus, a belt is provided which has a base material, a strength member, and an antenna. The belt is designed to run annularly in the circumferential direction, wherein the strength member is embedded in the base material of the belt as a continuous, helically wound cord. The antenna is also embedded in the base material, so that there is a direct, material-to-material connection between the entire surface of the antenna and the base material. The connection between the antenna and the base material is designed such that stretching of the belt in the circumferential direction leads to a longitudinal stretching of the antenna. The antenna is designed for coupling into an alternating electromagnetic field, so that an electromagnetic wave with a resonant frequency is generated in the antenna.Furthermore, the antenna is designed such that the resonant frequency depends on the length of the antenna. The antenna is designed to vary the alternating electromagnetic field, so that the change in the alternating electromagnetic field represents a longitudinal extension of the antenna.

[0007] The antenna embedded in the base material of the belt offers several advantages. For example, the antenna is protected from external mechanical influences by the base material. Furthermore, forces acting on the belt in the circumferential direction can be transmitted directly to the antenna via the base material, so that an extension of the belt leads to a corresponding longitudinal extension of the antenna. Antennas are generally known from the prior art. The antenna can, for example, be a wire-shaped antenna and / or a rod-shaped antenna. Due to its ability to couple into the alternating electromagnetic field, the antenna is designed to change the alternating field. The change depends on the electromagnetic wave generated in the antenna, which in turn depends on the length and / or the longitudinal extension of the antenna.The antenna is thus designed to vary the alternating electromagnetic field depending on the length and / or longitudinal extension of the antenna. As a result, the change in the alternating field represents the longitudinal extension of the antenna. The longitudinal extension of the antenna is preferably a relative extension of the length of the antenna. The longitudinal extension can, for example, refer to a length of the antenna in a predetermined initial state. The antenna can also be referred to as a radio antenna and / or be designed as a radio antenna. Therefore, the antenna can be designed to couple in and / or vary the alternating field, which preferably takes place wirelessly and / or via radio.

[0008] The belt with the antenna embedded in the associated base material therefore offers the possibility of wirelessly and instantaneously inferring the longitudinal expansion of the antenna and, based on this, the longitudinal expansion of the belt. Preferably, the longitudinal expansion of the antenna corresponds to the longitudinal expansion of the belt. However, a linear relationship, in particular a constant factor, can also exist between the two longitudinal expansions. The longitudinal expansion of the belt preferably refers to the section of the belt in which the antenna is embedded in the associated base material. Thus, a local expansion of the belt can be inferred wirelessly and / or instantaneously. If the alternating field is detected, the change in the alternating field can also be detected. Based on this, a change in the expansion of the belt during operation can be inferred at least at a fixed point in time and / or continuously.This does not require any interruption of operation. Furthermore, no electrical evaluation circuitry needs to be integrated into the belt for the antenna. Instead, the belt can be designed to withstand particularly high temperatures. This also applies particularly to the base material and / or the antenna.

[0009] The base material of the belt can be formed at least partially from rubber material and / or at least partially from polyurethane material. The base material is preferably made of rubber material or polyurethane material. The base material can be electrically insulating. This offers the advantage that the antenna can be embedded in the belt in an electrically insulated manner by the base material. The insulation allows a change in the electromagnetic alternating field to represent the longitudinal expansion of the antenna that is robust against interference variables. This is because the electrical insulation of the antenna can prevent the resonant frequency of the wave in the antenna from being disturbed by other, in particular electrically conductive elements and / or active components in the belt. The antenna can be arranged and / or formed separately from other possible components in the belt by means of the base material, preferably mechanically insulated and / or electrically insulated.The insulation can therefore also refer to a mechanical separation from other components.

[0010] The cord embedded in the base material can be formed, for example, from a metal wire or from a ribbon-, fiber-, or wire-shaped filament made of plastic. The cord is embedded in the base material in several turns in the circumferential direction of the belt, so that the cord is embedded in the base material continuously and helically wound. The belt is therefore preferably designed as a drive belt, a transmission belt, or a transmission belt. The belt can serve to transmit forces in the circumferential direction of the belt. The belt is preferably not designed as a conveyor belt and also preferably not as a conveyor belt.

[0011] The antenna is preferably embedded in an elongated form into the base material of the belt. This particularly advantageously ensures that stretching of the belt leads to a corresponding stretching of the antenna. However, the elongated design of the antenna is not absolutely necessary. The antenna can also have another advantageous geometric shape. For example, it has proven advantageous if the antenna is coiled and / or spiral-shaped and is embedded in a corresponding shape in the base material. The antenna preferably has several turns. In this form, the antenna can also be embedded, for example, coiled around a strand section of the cord that is also embedded in the base material. However, it is also possible for the antenna to be embedded in the base material in a different geometric shape.For example, the antenna can be designed as a flat band antenna and / or as a film-shaped antenna. In the latter case, the antenna can be made from a film that is embedded in the base material. The film can have a thickness of between 5 micrometers and 0.5 mm. The antenna can extend over a predetermined length. It is also possible for the antenna to extend over a (further) predetermined length in the circumferential direction of the belt. Furthermore, it is possible for the antenna to extend over a predetermined width of the belt and / or over the entire width of the belt. However, it is preferably provided that the antenna does not extend all the way to the side flanks of the belt in order to prevent the antenna from coming into contact with external objects, in particular pulleys.A particularly advantageous and easy-to-manufacture antenna has a wire or rod shape with an average diameter between 5 micrometers and 0.5 mm. This antenna can be embedded in the base material of the belt in an elongated form in the circumferential direction of the belt.

[0012] An advantageous embodiment of the belt is characterized in that fabric layers are embedded in the base material. The fabric layers preferably serve to reinforce the belt, in particular to reinforce the cross-section of the belt. The fabric layers or at least one fabric layer can also be arranged on the outside of the base material. The antenna of the belt can be woven into the fabric material and / or surrounded by the fabric material. This allows forces acting on the belt in the circumferential direction of the belt to be transmitted particularly reliably to the antenna, so that stretching of the belt leads to a corresponding longitudinal stretching of the antenna.

[0013] A further advantageous embodiment of the belt is characterized in that the antenna is designed as a purely passive antenna. The antenna therefore preferably has no active electrical components. Furthermore, it is preferably provided that the antenna is not electrically connected to any other electrical component, in particular to any other active electrical component. The antenna is preferably designed as a single piece. This allows the antenna to be embedded in the base material and thus separated from other components by the base material and / or electrically insulated by the base material. The change in the alternating field caused by the antenna can therefore particularly reliably represent the elongation of the antenna without being influenced by other physical effects.

[0014] An advantageous embodiment of the belt is characterized in that the antenna is formed from a metal wire. The metal wire can form a particularly bend-robust and at the same time advantageous design of the antenna. Preferably, the antenna is formed from a metal wire stretched in the circumferential direction of the belt. The metal of the metal wire can be a ferromagnetic material. Furthermore, the antenna is preferably designed to be electrically conductive. This ensures that the antenna is designed to couple in the alternating electromagnetic field in such a way that an electromagnetic wave can be generated in the antenna at the resonant frequency. However, the metal wire can also be embedded in the base material in a different geometric shape. For example, the metal wire forming the antenna can be coiled, preferably coiled around a cord in the belt.Other advantageous geometric designs of the metal wire to form the antenna are also possible.

[0015] An advantageous embodiment of the belt is characterized in that the antenna is designed as a printed, electrically conductive line. The antenna can be formed by a printed metallic rod and / or wire. However, it is also possible for the antenna to be formed from a material mixture of metallic material and another printable material. During production of the belt, the antenna can be printed at a designated location in order to then completely embed the antenna in the base material. This enables particularly simple and precise embedding of the antenna in the base material.

[0016] An advantageous embodiment of the belt is characterized in that the antenna is formed from an electrically conductive rubber strand. This rubber strand can be formed from a different material than the base material. Ferromagnetic material and / or substance can be admixed with the rubber strand. In particular, it is preferably provided that the base material is electrically insulating and that the rubber strand is electrically conductive. However, it is also possible for the conductivity of the electrically conductive rubber strand as a configuration of the antenna to be at least ten times the conductivity of the base material of the belt. This applies in particular when the base material is formed entirely or partially from rubber material. The rubber strand can have an average thickness and / or an average diameter of up to 3 mm. Other dimensions are also possible, however.The electrically conductive rubber strand designed as an antenna is also embedded in the base material. This is particularly possible when the base material is formed from rubber. In this case, a connection between the antenna, namely formed here by the electrically conductive rubber strand, and the base material, in particular formed from a different rubber material, can be designed such that an expansion of the belt in the circumferential direction leads to a longitudinal expansion of the antenna. This is because the rubber strand can have a material-to-material connection to the base material, in particular if it is formed from rubber material. This allows a particularly precise detection of the expansion of the belt by means of the antenna and a correspondingly precise change in the alternating field, depending on the expansion of the antenna and / or the belt.

[0017] A further advantageous embodiment of the belt is characterized in that the antenna is formed from an electrically conductive polyurethane strand. The previously mentioned advantageous explanations, preferred features, effects and / or advantages discussed in connection with the electrically conductive rubber strand as a configuration of the antenna preferably apply analogously to the electrically conductive polyurethane strand as a further configuration of the antenna. It should also be noted at this point that the base material can be formed entirely or partially from a different polyurethane material instead of rubber material. Therefore, the corresponding explanations, features, effects and / or advantages, as explained with reference to rubber, can apply correspondingly to polyurethane.

[0018] A further advantageous embodiment of the belt is characterized in that the antenna is arranged without contact to the strength member. It is therefore preferably provided that the antenna has no direct contact with the strength member or the coiled cord and / or the fabric insert. Rather, it is preferably provided that the antenna is embedded in the base material in such a way that the antenna is completely covered by the base material. This is particularly advantageous if the base material is electrically insulating. This is because it can effectively prevent a negative effect on the generation of the resonant frequency in the antenna. Rather, the resonant frequency is then at least substantially determined by the length of the antenna. By designing the antenna without contact to the strength member, it is also prevented that the antenna can rub against the strength member when the belt is in use.This prevents wear on the antenna and / or the reinforcement. Both must be avoided. Firstly, the shape and / or geometric arrangement of the antenna must be prevented from being altered by friction. This is the only way to ensure reliable measurements. Friction between the antenna and the reinforcement must also be avoided to ensure that the reinforcement does not develop a friction-related weak point. Rather, friction of the reinforcement must be prevented as much as possible so that the reinforcement retains the desired tensile strength.

[0019] A further advantageous embodiment of the belt is characterized by the fact that it is free of active, electrical components. Active electrical components increase the complexity of the belt. However, this should be avoided, as the belt is often used under high mechanical loads and / or high thermal loads. By not having any active electrical components, the belt can be ensured to be particularly robust, in particular mechanically and / or thermally robust. This has the effect that the belt provides a particularly robust option for indirectly detecting force peaks in the system.

[0020] According to a second aspect of the invention, the object mentioned at the outset is achieved by a device having the features of claim 9. A device is therefore provided which has a transmitter and an evaluation unit. The evaluation unit can be combined with the transmitter and / or formed integrally. The transmitter can be referred to and / or formed as a transmitter unit. The transmitter is designed to generate an alternating field into which an antenna can be coupled, which causes an electromagnetic wave in the antenna with a resonant frequency that depends on a length of the antenna and a change in the alternating field such that the change in the alternating field represents a longitudinal expansion of the antenna. The transmitter is also designed to detect the change in the alternating field.The evaluation unit is configured to determine the longitudinal extension of the antenna based on the detected change in the alternating field, preferably in a predetermined range around the resonance frequency. Furthermore, the evaluation unit is configured to determine a length value representing a longitudinal extension of the belt based on the longitudinal extension of the antenna.

[0021] As already mentioned, it is preferably provided that the transmitter and the evaluation unit are designed as a common or combined unit, which can also be referred to as a transmitter-evaluation unit. This common or combined unit can also form the device or at least form part of the device.

[0022] The transmitter is designed to generate the alternating field, which is an alternating electromagnetic field. For this purpose, the transmitter can, for example, have an electrical circuit, such as a resonator circuit, which is designed to generate the alternating electromagnetic field. For this purpose, the circuit can, for example, have at least one electrical coil. An antenna, in particular the antenna of the belt according to the first aspect of the invention, can be brought into this alternating electromagnetic field. For example, the belt can be driven in such a way that the antenna is moved into the alternating electromagnetic field generated by the transmitter. The preferred embodiments, preferred features, effects and / or advantages, as explained above for the antenna in connection with the belt, are therefore not applicable to the antenna of a belt which iswhich is moved into the alternating electromagnetic field of the transmitter, is referred to in an analogous manner. The antenna can therefore be designed to couple into the alternating electromagnetic field that can be generated by the transmitter, so that the electromagnetic wave is generated in the antenna with the resonant frequency. As explained previously, the resonant frequency depends on the length of the antenna, so that the antenna is designed to change the alternating field, in such a way that the change in the alternating field represents a longitudinal extension of the antenna. The transmitter is also designed to detect the change in the alternating electromagnetic field, whereby the change depends on the antenna or the longitudinal extension of the antenna. The change in the alternating electromagnetic field detected by the transmitter therefore represents the longitudinal extension of the antenna.To detect the alternating electromagnetic field, the transmitter can have at least one corresponding electrical circuit, in particular with at least one coil.

[0023] Furthermore, the evaluation unit is configured to determine the longitudinal extension of the antenna. It should be noted again that the transmitter can preferably detect the change in the alternating field beforehand, with the change in the alternating electromagnetic field representing the longitudinal extension of the antenna. This information is therefore used by the evaluation unit to determine the longitudinal extension of the antenna based on the detected change in the alternating field. The change in the alternating field preferably occurs in a predetermined frequency range of the alternating electromagnetic field around the resonant frequency corresponding to the electromagnetic wave in the antenna.

[0024] The evaluation unit is also configured to determine a length value representing a longitudinal extension of the belt based on the longitudinal extension of the antenna. The longitudinal extension of the belt can be a relative extension of the length of the belt and / or a relative extension of a length of a section of the belt in which the antenna is arranged. The longitudinal extension of the belt preferably refers to the length of the belt or the length of the section of the belt, respectively, in a predetermined initial state.

[0025] The length value, which represents the longitudinal elongation of the belt, can be used to monitor the belt. For example, the measured length value can be evaluated to determine the belt's condition.

[0026] The transmitter and / or the device is / are preferably arranged at a predetermined distance from the belt to avoid contact with the belt. This minimizes the influence of the device on the operation of the belt.

[0027] An advantageous embodiment of the device is characterized in that a circumferential length of the belt is stored by the evaluation unit, wherein the evaluation unit is configured to determine a longitudinal elongation value, which represents an absolute change in length of the belt, based on the length value and the circumferential length of the belt. An absolute change in length of the belt determined in this way can be of interest for the use of the belt in active operation. In particular, a status value can be derived from this value, which provides information about the operating status of the belt.

[0028] A further advantageous embodiment of the device is characterized in that the evaluation unit is configured to determine a remaining service life of the belt based on a history of determined longitudinal values ​​and / or longitudinal elongation values. The device or the associated evaluation unit can thus be designed to determine several longitudinal values ​​and / or longitudinal elongation values ​​one after the other. The determination can take place at fixed intervals. However, it is also possible for the determination to be triggered by the detection of the change in the alternating field. The detected longitudinal elongation values ​​and / or longitudinal values ​​can be stored by the evaluation unit. Based on these determined longitudinal values ​​and / or longitudinal elongation values, the evaluation unit can therefore be configured to determine a remaining service life of the belt.A correspondingly determined remaining service life can be used to plan the maintenance intervals and / or the replacement of the belt in advance.

[0029] According to a third aspect, the object mentioned at the outset is achieved by a system having the features of claim 12. A system is therefore provided which has a belt and a device. The belt is preferably a belt according to the first aspect of the invention and / or one of the associated, advantageous embodiments. With regard to the belt, reference is made at least analogously to the explanations of advantageous, preferred features, advantages and / or effects as have already been explained for the belt. The device of the system is preferably the device according to the second aspect of the invention and / or one of the associated, advantageous embodiments.With regard to the device, reference is made at least in an analogous manner and preferably to the explanations of advantageous, preferred features, effects and / or advantages as have been discussed in connection with the device already explained.

[0030] The antenna that can be coupled into the alternating field generated by the device's transmitter is the antenna of the belt.

[0031] An advantageous embodiment of the system is characterized in that the system has at least two pulleys, wherein the belt at least partially wraps around the pulleys, wherein a length of the antenna of the belt is less than the smallest span length, in particular of the at least one tension span, of the belt. The length of the antenna can therefore be less than the smallest span length of the at least one tension span of the belt. In other words, it can be provided that the length of the antenna is less than the smallest span length of a tension span of the belt. This makes it particularly easy to ensure that the antenna is arranged completely in the tension span of the belt between two pulleys at least for one point in time and / or a predetermined period of time as the belt revolves around the pulleys.In addition, the transmitter can be arranged in such a way that the alternating electromagnetic field penetrates the area between the pulleys in which the tensioning strand is located. This ensures that the antenna can be coupled into the alternating electromagnetic field if the antenna is arranged in the tensioning strand. This in turn offers the possibility of detecting the load acting in the tensioning strand using the antenna. This is because the antenna is subject to longitudinal stretching caused by the stretching of the belt. The belt is usually subject to the greatest stretching in the tensioning strand. This also often corresponds to the greatest load on the belt. If the antenna is therefore coupled into the alternating field generated by the transmitter in the tensioning strand, the transmitter can also detect the change in the alternating field caused by the antenna, whereby the changed alternating field represents the longitudinal stretching of the antenna.The evaluation unit of the system device can use this information to determine the longitudinal extension of the antenna and / or to determine the longitudinal extension of the belt. Furthermore, the evaluation unit can be configured to determine the longitudinal extension value, which represents an absolute change in the length of the belt, based on the longitudinal extension of the belt and a circumferential length of the belt.

[0032] A further advantageous embodiment of the belt is characterized in that the antenna length is a maximum of 90%, 80%, 70%, 60%, or 50% of the span length. This is preferably the smallest span length, in particular the smallest span length of a tension span of the belt. Because the antenna length, i.e. the length of the antenna in the circumferential direction, is smaller than the previously mentioned preferred span length, it is particularly easy to ensure that the stretching of the belt in the corresponding span leads to a correspondingly equal longitudinal stretching of the antenna. This allows reliable detection of the longitudinal stretching of the antenna or the longitudinal stretching of the belt.

[0033] An advantageous embodiment of the system is characterized in that the transmitter, in particular as part of a combined transmitter-evaluation unit, and / or the entire device is arranged at a predetermined distance of between 1 mm and 50 cm from a strand of the belt. This is preferably a tension strand of the belt. The predetermined distance ensures that the transmitter has no direct mechanical contact with the belt. The transmitter therefore has no negative mechanical influence on the belt. The operation of the belt as such is not negatively influenced by the transmitter or the device. Rather, the longitudinal expansion of the antenna and / or the longitudinal expansion of the belt can be detected and / or determined during operation without any negative influence on the system or the belt.

[0034] Further features, advantages, and possible applications of the present invention will become apparent from the following description of the exemplary embodiments and the figures. All described and / or illustrated features, individually and in any combination, constitute the subject matter of the invention, regardless of their composition in the individual claims or their references. In the figures, the same reference numerals continue to represent the same or similar objects. Figure 1 shows an advantageous embodiment of the system with an advantageous embodiment of the belt and an advantageous embodiment of the device, each in a schematic view. Figure 2 shows a section of an advantageous embodiment of the belt in a schematic view. Figure 3 shows a section of another advantageous embodiment of the belt in a schematic view. Figure 4 shows a section of the reinforcement member advantageously configured as a cord, wherein at least some of the antennas are coiled around the cord.

[0035] In the Figure 1 An advantageous embodiment of the belt 2 is shown schematically. In addition, Figure 1 the device 16 and the system 22 are shown schematically in an advantageous embodiment.

[0036] Although the Figure 1Since the schematically illustrated belt 2 forms part of a belt drive 30, the belt 2 may relate to a separate aspect of the invention. The device 16 may form a further aspect of the invention. Furthermore, an aspect of the invention may relate to the system 22, which comprises the device 16 and the belt 2. In the following, the belt 2 will be discussed first.

[0037] An advantageous embodiment of the belt 2 is shown in Figure 2shown schematically using a section of the belt 2 in a semi-transparent manner. The belt 2 has a base material 4, which consists for example of rubber material or polyurethane material. The belt 2 also has a strength member 6. The strength member 6 is embedded in the base material 4 of the belt 2 as a wire-shaped, helically wound cord 10. The strength member 6 or the cord 10 is therefore preferably wound several times in the circumferential direction U of the belt 2 and thus embedded helically in the base material 4. The individual turns of the cord 10 can be separated by the base material 4 of the belt 2. The cord 10 is preferably a continuous, i.e. uninterrupted cord 10. The cord 10 can be a wire rope, for example, or be formed from a rope made of plastic fibers. In principle, the belt 2 can have several strength members 6.However, purely by way of example, it is assumed that the belt 2 has only one strength member 6, which is embedded in the base material 4 of the belt 2. The belt 2 is designed to be annular in the circumferential direction U. The same can therefore apply to the windings of the strength member 6.

[0038] The belt 2 also has an antenna 8. The antenna 8 is embedded in the base material 4 of the belt 2. The antenna 8 is preferably designed as a purely passive antenna 8. It is therefore not coupled to other electronic components. Rather, it is preferably provided that the antenna 8 is completely enveloped and embedded in the base material 4 of the belt 2. This ensures that the antenna 8 is arranged without contact with the strength member 6 of the belt 2. This in turn offers the advantage that the antenna 8 does not cause any friction on the strength member 6, even when the belt 2 is loaded. This particularly effectively ensures that no friction and / or wear is caused on the antenna 8 and / or on one of the windings of the strength member 6 during operation of the belt 2. The belt 2 is therefore particularly robust.

[0039] An advantageous embodiment of the belt 2 is characterized in that the antenna 8 is embedded in the base material 4 in a manner stretched in the circumferential direction U of the belt 2. In addition, the antenna 8 is embedded in the base material 4 in such a way that a direct material connection exists between the entire surface 12 of the antenna 8 and the base material 4. The connection between the antenna 8 and the base material 4 is therefore designed in such a way that an elongation of the belt 2 in the circumferential direction U leads to a longitudinal elongation of the antenna 8. This applies in particular if the elongation occurs in a part of the belt 2 in the circumferential direction U in which the antenna 8 is arranged. For example, if the Figure 2 If the section of the belt 2 shown is stretched, this leads to a corresponding longitudinal stretching of the antenna 8.

[0040] The Figure 1The exemplary embodiment of the device 16 can have a transmitter 18. The transmitter 18 is preferably designed to generate an alternating electromagnetic field 14. The transmitter 18 can be arranged at a distance from a strand 28 of the belt 2 such that the alternating electromagnetic field 14 that can be generated by the transmitter 18 penetrates the strand 28 of the belt 2.

[0041] The belt 2 is characterized in that the antenna 8 embedded in the base material 4 is designed for coupling into the alternating electromagnetic field, so that an electromagnetic wave with a resonant frequency is generated in the antenna 8. The antenna 8 is designed such that the resonant frequency depends on a length A of the antenna 8. Stretching the antenna 8 in the circumferential direction U can lead to an increase in the resonant frequency.

[0042] The antenna 8 of the belt 2 is also designed to change the alternating electromagnetic field 14. This is because the coupling of the antenna 8 into the alternating electromagnetic field 14 results in a reaction from the antenna 8 to the alternating electromagnetic field 14, whereby the reaction depends on the resonant frequency of the electromagnetic wave generated in the antenna 8. The resonant frequency, in turn, depends on the length A of the antenna 8. This results in a dependence of the change in the alternating field 14 by the antenna 8 on the length A of the antenna 8 or a longitudinal extension of the antenna 8. Therefore, the antenna 8 is designed to change the alternating electromagnetic field 14 in such a way that the change in the alternating electromagnetic field 14 represents a longitudinal extension of the antenna 8.

[0043] For example, the expansion of antenna 8 in the circumferential direction U can increase the resonant frequency of the electromagnetic wave generated in antenna 8, which in turn has a feedback effect on the frequency spectrum of alternating electromagnetic field 14. The frequency spectrum can thus be subject to a shift corresponding to the change in the resonant frequency. This change in the frequency spectrum of alternating electromagnetic field 14 is therefore representative of the elongation of antenna 8.

[0044] The Figure 1The transmitter 18 shown by way of example can also be designed to detect the alternating electromagnetic field 14, in particular to detect the change in the alternating electromagnetic field 14. Furthermore, it is preferably provided that the evaluation device 20 of the device 16 is coupled to the transmitter 18 and / or that the evaluation unit 20 and the transmitter 18 form a combined and / or common unit. Furthermore, the evaluation unit 20 is preferably configured to determine the longitudinal extension of the antenna 8 based on the detected change in the alternating electromagnetic field 14. As a result, the device 16 can be used to contactlessly determine an extension of a belt 2 without interrupting the operation of a belt drive 30 with the belt 2 according to the invention.

[0045] As already noted above, another aspect of the invention relates to the device 16. This is indicated by the dashed line in Figure 1 shown schematically. The device 16 comprises the transmitter 18 and the evaluation unit 20. The two units 18, 20 can be formed integrally or separately. If the transmitter 18 and the evaluation unit 20 are formed separately, the two units 18, 20 can be coupled to one another by a signal connection 32 in order to transmit a detection signal provided by the transmitter 18, which represents the change in the alternating field 14, to the evaluation unit 20.

[0046] A further aspect of the invention relates to the system 22, which comprises the belt 2 and the device 16. The device 16 is preferably arranged at a predetermined distance K, which is preferably less than 50 cm, less than 20 cm, or less than 10 cm, from a run 28 of the belt 2, particularly when the belt 2 at least partially wraps around two pulleys 24, 26 of a belt drive 30. The system 22 can therefore also comprise the belt drive 30 with the two pulleys 24, 26.

[0047] During operation of the belt drive 30, the belt 2 is driven in such a way that the belt 2 rotates and is deflected accordingly by the two pulleys 24, 26. At a constant speed of the belt 2 in the circumferential direction U, the antenna 8 of the belt 2, which is embedded in the base material 4, passes the transmitter 18 of the device 16 at periodic intervals. The antenna 8 is exposed to the alternating electromagnetic field 14 generated by the transmitter 18. The transmitter 18 is also designed to detect changes in the alternating electromagnetic field 14. This change in the alternating electromagnetic field 14 is evaluated by the evaluation unit 20 in order to determine a longitudinal extension of the antenna 8. Furthermore, this longitudinal extension of the antenna 8 can be used by the evaluation unit 20 to determine a longitudinal extension of the belt 2.This longitudinal extension of the belt 2 preferably refers to the section of the belt 2 in which the antenna 8 is arranged.

[0048] It is advantageous if the device 16 is arranged opposite a tension strand 34 of the belt 2 of a belt drive 30. This is because the tension strand 34 of the belt 2 of a belt drive 30 is usually subject to the highest tensile force acting in the circumferential direction U, which leads to the greatest stretching of the belt 2 during operation. By arranging the device 16 and / or preferably the associated transmitter 18 opposite, preferably at a predetermined distance K, the tension strand 34 of the belt 2, a variable particularly relevant to the condition of the belt 2, namely the longitudinal stretch of the antenna 8 and / or the longitudinal stretch of the belt 2, can be determined.

[0049] In order to record the aforementioned variables as robustly as possible against external influences, it has proven advantageous if the length A of the antenna 8 is smaller than the smallest span length of the tension span 34 of the belt 2. In this case, the antenna 8 passes through the tension span 34 at least at one point in time during the rotation of the belt 2 in such a way that the antenna 8 is not in a wrap-around area 38, 40 of one of the two pulleys 24, 26. In this case, a particularly large change in the alternating field 14 can be detected by the transmitter 18, which is representative of the maximum load or stretch of the belt 2.

[0050] A further advantageous embodiment of a belt 2 is shown schematically and with reference to a section of the belt 2 in the Figure 3. Here, the antenna 8 is formed by a plate-shaped or film-shaped body, in particular made of metal. The antenna 8 is not arranged between the strength members 6. Rather, it is preferably provided that the antenna 8 is embedded above or below the strength members 6 in the base material 4 of the belt 2. Furthermore, it can be provided for the antenna 8 to be elongated in the circumferential direction U.

[0051] However, the design of the antenna 8 extending in the circumferential direction U does not mean that the antenna 8 cannot also extend and be formed in the transverse direction Q of the belt. In principle, it is also possible for the antenna 8 to be designed to extend across the entire width in the transverse direction Q.

[0052] A further advantageous embodiment of a shape for the antenna 8 is shown schematically in Figure 4. Here, the antenna 8 is shown in a helical and / or spiral configuration. The antenna 8 is arranged coiled around a strand of the cord 10 without touching the cord 10.

[0053] Additionally, it should be noted that "comprising" does not exclude other elements or steps, and "a" or "an" does not exclude a plurality. Furthermore, it should be noted that features described with reference to one of the above embodiments may also be used in combination with other features of other embodiments described above. Reference signs in the claims are not to be considered as limitations. List of reference symbols (part of the description)

[0054] AAntenna length KAspacing QTransverse direction UCircumferential direction 2Belt 4Base material 6Strength support 8Antenna 10Cord 12Surface 14Alternating field 16Device 18Transmitter unit 20Evaluation unit 22System 24Pulley 26Pulley 28Trunk 30Belt drive 32Signal connection cable 34Tension strand 36Wrap area 38Wrap area

Claims

1. Belt (2), comprising: a base material (4), in particular at least partially of rubber material or polyurethane material, a reinforcing element (6) and an antenna (8), preferably in the form of a wire, the belt (2) being designed as circulating in a circumferential direction (U) in the form of a ring, the reinforcing element (6) being embedded in the base material (4) as a continuous, helically coiled cord (10), the antenna (8) being embedded in the base material (4), preferably in a form in which it is made to extend in the circumferential direction (U) of the belt (2), so that there is a direct material bond between the entire surface (12) of the antenna (8) and the base material (4), the bond between the antenna (8) and the base material (4) being formed in such a way that an elongation of the belt (2) in the circumferential direction (U) leads to a longitudinal elongation of the antenna (8), the antenna (8) being designed for coupling into an electromagnetic alternating field (14), so that an electromagnetic wave is produced in the antenna (8) with a resonant frequency, the antenna (8) being designed in such a way that the resonant frequency depends on a length of the antenna (8), and the antenna (8) being designed to change the alternating field (14), so that the change in the alternating field (14) represents a longitudinal elongation of the antenna (8).

2. Belt (2) according to the preceding claim, characterized in that fabric layers are embedded in the base material (4).

3. Belt (2) according to one of the preceding claims, characterized in that the antenna (8) is designed as a purely passive antenna (8).

4. Belt (2) according to one of the preceding claims, characterized in that the antenna (8) is formed by a metal wire.

5. Belt (2) according to either of the preceding Claims 1 and 2, characterized in that the antenna (8) is formed as a printed, electrically conductive line.

6. Belt (2) according to either of the preceding Claims 1 and 2, characterized in that the antenna (8) is formed by an electrically conductive rubber strand or by an electrically conductive polyurethane strand.

7. Belt (2) according to one of the preceding claims, characterized in that the antenna (8) is arranged free from contact with the reinforcing element (6).

8. Belt (2) according to one of the preceding claims, characterized in that the belt (2) is formed free from active electrical components.

9. Device (16), comprising: a transmitter (18) and an evaluation unit (20), which may be combined with the transmitter, the transmitter (18) being designed for generating an alternating field (14) into which an antenna (8) can be coupled, which induces an electromagnetic wave in the antenna (8) with a resonant frequency which depends on a length of the antenna (8) and induces a change in the alternating field (14) in such a way that the change in the alternating field (14) represents a longitudinal elongation of the antenna (8), the transmitter (18) being designed for detecting the change in the alternating field (14), the evaluation unit (20) being configured to determine the longitudinal elongation of the antenna (8) on the basis of the detected change in the alternating field (14), preferably in a predetermined range around the resonant frequency, and the evaluation unit (20) being configured to determine on the basis of the longitudinal elongation of the antenna (8) a length value which represents a longitudinal elongation of the belt (2).

10. Device (16) according to Claim 9, characterized in that a circumferential length of the belt (2) is stored by the evaluation unit (20), the evaluation unit (20) being configured to determine on the basis of the length value and the circumferential length a longitudinal elongation value which represents an absolute change in length of the belt (2).

11. Device (16) according to either of the preceding Claims 9 and 10, characterized in that the evaluation unit (20) is configured to determine on the basis of a history of determined longitudinal values and / or longitudinal elongation values a remaining service life of the belt (2).

12. System (2), comprising: a belt (2) according to one of the preceding Claims 1 to 8, and a device (16) according to one of the preceding Claims 9 to 11.

13. System (2) according to the preceding claim, characterized in that the system (2) has at least two belt pulleys (24, 26), the belt (2) wrapping at least partially around the belt pulleys (24, 26), a length of the antenna (8) being less than the smallest length of a side of the belt (2).

14. System (2) according to the preceding claim, characterized in that the maximum antenna length (A) is 90%, 80%, 70%, 60% or 50% of the length of a side.

15. System (2) according to one of the preceding Claims 12 to 14, characterized in that the transmitter (18), in particular as part of a combined transmitter / evaluation unit, and / or the entire device (16) is arranged at a distance (K) of between 1 mm and 50 cm from a side (28) of the belt (2).