Extraction device, particularly for mining, and method for controlling the extraction device

[0001] The invention relates to a mining device, in particular for mining, with a first drive station and with a second, preferably by means of a tensioning mechanism mounted drive station, with chain wheels mounted in these drive stations, consisting of chain links and moved and / or recycled by means of motor-driven chain wheels a drive chain which extends between the sprockets in the upper and lower compartment and with at least one magnetic sensing device for detecting at least one state of the drive chain in the upper compartment or in the lower compartment. The invention also relates to a method of controlling a mining device, in particular for mining, with a first drive station and with a second, preferably by means of a tensioning mechanism mounted drive station,

[0002] For the working mode of a mining device with a circulating or reversibly driven drive chain, it is very important to evaluate or test, using appropriate means, the condition of the drive chain, and in particular the initial tension of the chain. In principle, in this respect, optical, electrical, magnetic and mechanical sensor devices have been proposed to provide data to determine the stress state of the drive chain and calculate control parameters for the tensioning device, or drive motors for drive stations based on relevant algorithms.

[0003] DE 34 06 519 A1 proposes the use of a magnetically operating sensing device that allows magnetic detection of the chain tension at the drive tensioning stations. The magnetic field generator proposed for this purpose in the solution according to DE 34 06519 is assigned to the chain compartment running from the drive station each time. The magnetic field generator designed for measuring the tension of the drive chain in the upper compartment is embedded in the bottom plate, and the magnetic field generator for measuring the tension of the drive chain in the lower compartment is embedded in the bottom sheet of the drive station above the lower compartment, which allows detection of magnetic field deformation resulting from changes distance between the test drive chain and chain links. In addition to the through chain, it should be possible to adjust the spacing between scrapers of the conveyor chain or to change the spacing between the chain links in combination with the regulation of the through-chain. The measuring principle, presented in DE 34 06 519, consists in generating a directional magnetic field, detuned as a result of diversified penetration of chain links into this magnetic field, whereby the detuning of the magnetic field under study can be estimated using measuring technique. Since the magnetic measuring sensor, including the measuring device, is embedded in the sheet metal bottom of the chain outlet, there is high wear, resulting in a very limited life span of such a magnetic measuring system.

The object of the invention is to develop a mining device design, as well as a method of commissioning a mining device, which will allow a reliable determination of the drive chain condition with a maintenance-free sensor device, with high system reliability with clearly increased service life.

[0005] From DE 201 17 949, a method and associated device for decreasing the power of drives for scraper chain conveyors is known, in which devices measuring the length of the chain from its longitudinal position can optically, electrically, magnetically or mechanically, also generate control parameters, on the basis of these parameters, to control the chain tensioning mechanisms in such a way that the chain slack in the outlet compartment is maintained, without exceeding the assumed value up or down. One transmitter of the measurement parameters reacts to the tension of the chain, i.e. to the reduction of the distance, and the other transmitter of the measurement parameters reacts to the increasing clearance, thus increasing the chain interval in the chain section from the optimal course. As a measuring parameter transmitter, for example, a penetrating drive station is described for a crosswise, intermittent radius interrupted by a chain link and then generating a corresponding pulse. Alternatively, inductive or capacitive transmitters, non-contact transmitters, and mechanical transmitters are also mentioned as basic measuring parameters transmitters.

[0006] These and other tasks of the mining device according to the invention are carried out in such a way that each sensor device is formed by a magnetic field generator as a transmitter function and a detector comprising a detector field with a plurality of magnetic field detectors, wherein the detector and the transmitter they are made, or embedded, on the side of the culvert for the tested drive chain compartment. The system-technical advantage of the cutting device according to the invention lies in the fact that the sensor device does not make a technical estimate of the magnetic field deformation due to the differential spacing of the chain links relative to the magnetic field generator or detector, but discerns the change in position or the change in scraping height or chain transversely to the direction of the chain run. In the mining device according to the invention, the magnetic field is introduced into the drive chain and a measurement signal is established for each detector of the magnetic field of the detector zone. If there is a change in the position of the chain link or the scraper within the sensing zone compared to its position from the previous passage or relatively to the defined zero position, it can be derived from whether the chain link or rummage is in a forward or downward position. If at the same time a time signal is detected for each scraper or chain link, it is possible to detect differential mutual intervals of chain links from scrapers, on the basis of which it becomes possible to determine further states of the drive chain, such as chain wear, twisting, etc.

[0007] The detector and transmitter for the magnetic field made as detector zone can be located on the same side next to each other. In a preferred embodiment, the detector and transmitter are located opposite each other, so that the transmitter, on the one hand, introduces a magnetic field into chain links or scraper, and magnetic field detector detectors on the other side of the passage perform magnetic field research carried by chain links or scraper. In order to be able to detect detection chains in particular, it is particularly advantageous if the detector zone with multiple detectors extends over the height of the passage. In a particularly preferred embodiment, the detector zone is provided with a plurality of magnetic field detectors located next to each other and a plurality of magnetic field detectors located one above the other to examine the variable magnetic field in a sufficiently wide range, transmitted or passed further through the tested link or scraper transversely to the direction of passage. drive chain. For the sake of simplicity necessary to perform a range of calculations, magnetic field detectors can be arranged in rows and rows with constant distances. Due to the two-dimensionality of magnetic field detector configuration in the detector zone, measuring and testing of the transmitted magnetic field can be carried out using magnetic field detectors that, for example, measure,

[0008] It is very advantageous if the detector zone and / or the magnetic field generator are located in the periphery of the machine body or in the side walls of the drive station chain sprocket. The installation in the side walls or side walls means that neither the detector nor the magnetic field generator are subject to significant mechanical wear, because there is no contact between the detector chain or chain links or the transmitter and the transmitter and detector. In both side walls or side walls there is enough space available to integrate the detector zone and the transmitter for the magnetic field therein. To eliminate mutual interactions with the surrounding machine body structure, the detector zone and / or the transmitter are preferably located in a housing or supporting structure made of non-magnetic material, preferably brass, bronze, copper, aluminum, titanium, austenitic steel or alloys, ceramics or plastic. The material or material alloy used must meet all requirements in terms of explosion safety (for an aggressive and gas environment) for all applications.

[0009] By means of magnetic field generators it is possible, according to one embodiment of the invention, to create a static, temporal, permanent magnetic field. According to a preferred alternative embodiment, alternating magnetic field generators are used as transmitters to generate a dynamic alternating magnetic field. Thanks to the use of variable magnetic field generators as transmitters for a magnetic sensor device, a magnetic field is used for measuring, which prevents the occurrence of measurement errors due to the differentiated privileged magnetization directions of the tested chain links or scrapers. Tests carried out by the applicant have proved that that chain links and scrapers embedded in the drive chains of conveyors (chain scoops) during magnetization transverse to the direction of the drive chain run show distinctly different magnetic flux densities and the amplification of the magnetic field emitted by the magnetic generator. When using variable magnetic field generators, the dependence on the direction of magnetization of the tested chain links or scoops is eliminated, because the variable magnetic field is tested with detectors of the detector zone. In a particularly preferred embodiment, the transmitter or generator of an alternating magnetic field is formed by a rotating or rotatable magnet. The rotation speed of the magnet can be at least 100 rpm. and reach up to 1,000 rpm and more. Furthermore, the magnetic induction of the magnet may preferably be at least 0.5 T (Tesla). With rotating magnets or rotating magnets, the thing may in particular relate to a permanent magnet. The transmitter can hereby receive one or more rotating or rotating magnets to achieve high frequency variation of the alternating magnetic field even at low speed. Permanent magnets can be located especially in a rotating girder from non-magnetic material. To meet the requirements of explosion protection, the transmitter for a variable magnetic field preferably has a hydraulic rotational drive, in particular a hydraulic motor with a flow control valve for speed control. The hydraulic medium from the central underground hydraulic supply network for the casing section or the sandwich device can be fed to the hydraulic motor by a branch, the pressure of the medium being reduced by the pressure regulator to the value allowed for the hydraulic motor. Switching on and off can be carried out by means of multi-pilot pre-control valves. It is particularly advantageous if a rotary angle sensor is assigned to the rotary drive for the transmitter to determine the current angle of rotation of the modulator and transfer it to the control and computing unit. Switching on and off can be carried out by means of multi-pilot pre-control valves. It is particularly advantageous if a rotary angle sensor is assigned to the rotary drive for the transmitter to determine the current angle of rotation of the modulator and transfer it to the control and computing unit. Switching on and off can be carried out by means of multi-pilot pre-control valves. It is particularly advantageous if a rotary angle sensor is assigned to the rotary drive for the transmitter to determine the current angle of rotation of the modulator and transfer it to the control and computing unit.

In another variant of the embodiment, the magnet, or a plurality of transmitter magnets, can form a magnet system, the position and / or configuration of which varies with respect to the magnetic field sensor, which makes it possible in particular to generate an alternating magnetic field on the magnetic field thickness. To achieve this, the transmitter may advantageously be provided with a magnet system consisting of a plurality of concentric around the central axis of the ring magnets to be mounted, the ring system being able to be rotated axially by means of the actuator. It is particularly advantageous if it is possible to position the magnet system in different twisting positions with the actuator drive. This can be achieved, for example, by a self-locking actuator with a high reduction ratio,

[0011] The mining device can be made as a scraper conveyor in the drive chain and then each drive station is equipped for example with only one sensor device assigned to that compartment, which in each direction of the chain has an outlet from the drive station behind the chain wheel. As there is usually one main drive and one auxiliary drive on the conveyors, one sensor device would be located in the lower compartment of the main drive and the other sensing device in the upper compartment of the auxiliary drive. Alternatively, it may refer to a mining device such as, for example, a plow unit with a reversibly driven drive chain, whereby each drive station is equipped with two sensing devices, of which at each drive station one sensor device is assigned, or will be, an upper compartment and one sensor device to the lower compartment. In reversible chains, the drives of the drive stations, depending on the direction of the mining machine run, have to perform the main work task, so that the chain overhang can occur on each drive station, both before and after the chain. However, also for the conveyors, a sensor device can be assigned to each compartment in the drive station. so that the chain overhang can occur on each drive station, both before and after the sprocket. However, also for the conveyors, a sensor device can be assigned to each compartment in the drive station. so that the chain overhang can occur on each drive station, both before and after the sprocket. However, also for the conveyors, a sensor device can be assigned to each compartment in the drive station.

[0012] Furthermore, preferably a transmitter on the same side of the passage can be assigned magnetic field sensors for detecting the real magnetic field generated by the transmitter as a reference value.

The object of the invention defined at the outset is implemented in such a way that each sensor device generates a static magnetic field or a dynamic alternating magnetic field, tested by a plurality of magnetic field detectors arranged in the detector zone, wherein the tested drive chain interval passes between the generator the magnetic field and the detector zone, and on the basis of the change detected in the detector zone of the magnetic field or the alternating magnetic field, the state of the drive chain is determined.

In the method according to the invention, it is particularly advantageous that each detector of the magnetic field of the detector zone is emitted by the transmitter and transmitted by the drive chain, i.e. by chain links or scrapers, magnetic field or alternating magnetic field and from the detector position detecting the maximum field strength The state of the chain, in particular the location of chain links or scrapers, is determined. It is particularly advantageous if the calculation and control unit has such numbers as, for example, the number of revolutions of drive motors of the drive station and depending on the detected chain condition it is possible to adjust the number of revolutions and / or change the tension state of the tensioning device. The chain condition detected by the magnetic sensing device can be included in the actuation program of the tensioning device without determining the number of rotations. According to another variant of the method according to the invention using a transmitter generating a dynamic variable magnetic field, it is possible to detect the real magnetic field generated by the variable magnetic field transmitter and send it as a reference value to the calculation and control unit and / or determine the angle of rotation of the rotary drive for this transmitter and sending it as a reference value to the calculation and control unit. These reference values ​​can be used to additionally check the measured result in terms of the occurrence of measurement errors.

[0015] Since a single scraper, or individual chain link, as shown by the measurements made by the inventors, may exhibit not only different preferential directions, but even identical magnetization may have various changes in the introduced magnetic field or alternating magnetic field, and may also occur alternating interactions between adjacent scrapers or chain links, in a particularly preferred embodiment of the method according to the invention, a reference or calibration chain flight occurs at each stop of the drive chain in which a base magnetic induction reference value is determined for each cell or for each rake. in working mode it is compared to the currently measured value in the detector zone,as a result of which a change in the chain condition is determined, for example a change of position, or excessive consumption of individual chain links or scrapers.

[0016] Further advantages of the solution according to the invention have been presented in the embodiment in the drawing, where the individual figures show:

Fig. 1 is a schematic simplification of a mining device according to the invention made as a conveyor for underground mining;

Fig. 2 a drive station drive body for a mining device of Fig. 1 with a built-in sensor device in a large schematic simplification;

Fig. 3 AC position detection by means of a magnetic sensor device according to the invention on a system image, schematically simplified;

Fig. 4 a schematic view drawing of a mining device made as a plowing device with a sensing device according to the invention, similar to Fig. 1;

Fig. 5 AC detecting different chain positions in the plow device of Fig. 4;

Fig. 6 illustrates an embodiment of a variable magnetic field generator in a schematic simplified view from the front;

Fig. 7 illustrates an exemplary embodiment of a magnetic field generator with variable magnetic field, in schematic simplification, in a frontal view with partial opening; and

Fig. 8 is a magnetic field generator from Fig. 7 in top view.

[0017] Fig. 1 schematically shows a conveyor device 10 for underground mining. The conveyor device 10 includes known in the art: a first drive station 1 with schematically marked drive motor 2 and a chain wheel 3 and a second drive station 4 located at the other end of the conveyor device 10 with another chain wheel 5 and associated drive motor 6. Drive motors 2 and 6 may be suitably equipped depending on the purpose of their use, made as synchronous motors, frequency converters, etc. and may be equipped with gears, regulating devices, overload clutches, etc. Between the two sprockets 3, 5 in the transport direction indicated by the arrow F follows the endless chain link 6, wherein the mineral recovered from the wall of the underground excavation by means of appropriate mining tools is transported in the upper compartment 6A using schematically in FIGS. 2 and 3A-C the scuffles 11 in the direction towards the drive station 1, which is the main drive here. The upper compartment passing through the sprockets 3, 5 of the drive chain is assigned in FIG. 1 to the marking 6A, and the marking 6B has been assigned to the return compartment or to the idling compartment of the drive chain 6. In an underground conveyor system, the propulsive power has a higher propulsion force, into which the upper 6A range enters, and therefore in the lower compartment 6B behind the chain wheel 3 of the drive station 1, as well as in the lower compartment 6A behind the sprocket 5 of the drive station 4 there is a risk of chain slack. To compensate for the different stress states of the drive chain 6 using the conveyor device 10, the auxiliary drive, i.e. drive station 4, is assigned a hydraulic tensioning device 7 by means of which it is possible to change the spacing between the sprockets 3, 5 of the drive station 1.4. The extension or retraction of the tensioning device 7 is dependent on the control signal of the hydraulic control device 9 indicated by line 8. by means of which it is possible to change the distance between sprockets 3, 5 drive stations 1.4. The extension or retraction of the tensioning device 7 is dependent on the control signal of the hydraulic control device 9 indicated by line 8. by means of which it is possible to change the distance between sprockets 3, 5 drive stations 1.4. The extension or retraction of the tensioning device 7 is dependent on the control signal of the hydraulic control device 9 indicated by line 8.

The two sensor devices 20 are preferably mutually identical and comprise a transmitter which in the described embodiment generates a magnetic field and in Fig. 2 and Figures 3A-C has been marked with number 21, as well as a detector zone 22 with several side by side and one above the other. positioned magnetic field detectors 23 as a detector of variable magnetic field generated by the transmitter 21. A variable magnetic field transmitter 21 mounted in one of two planes 14 on one side of the culvert 15 for scoops 11 and chain links 12, 13 and the detector zone 22 is located on a second surface 15 facing the transmitter 21. In FIG. 2, the main drive station 1 forming the drive is shown schematically. The magnetic transmitter 21 and the detector zone 23 have been incorporated into the side walls 14, 15 in the region of the lower compartment 6B of the drive chain 6 in such a position in which, by changing the height of the scoops 11 relative to the tangential outlet from the sprocket 3, it is possible to detect the chain overhang which in Fig. 1 is shown in the form of a lowering 6 '. Both the transmitter 12 and the detector zone 22 can be embedded in a housing made of non-magnetic material. Also the sidings could be, at least partially, made of a suitable non-magnetic material. The magnetic field generator 21 may preferably consist of a permanent magnet, and in the absence of explosion protection requirements, an electromagnet that is mounted on a motor with an advantageously adjustable number of revolutions, with spinning speeds of up to 1000 rpm, allowing the generation of a modulated . a relatively dynamic magnetic field (variable magnetic field) for testing through the detector zone 22. The driving of one or more magnets is carried out, in particular, by means of a (not drawn) hydraulic motor which is rotated due to the flow of the hydraulic medium. The detector zone 22 in turn comprises a matrix with an appropriate number of magnetic field detectors 23 located side by side and one above the other, and by means of each individual magnetic field detector 23, it is possible to perform a magnetization test carried out on one side with a transmitter 21 on a scraper 11 and transient magnetization. The driving of one or more magnets is carried out, in particular, by means of a (not drawn) hydraulic motor, which is set in rotation due to the flow of the hydraulic medium. The detector zone 22 in turn comprises a matrix with an appropriate number of magnetic field detectors 23 located side by side and one above the other, and by means of each individual magnetic field detector 23, it is possible to perform a magnetization test carried out on one side with a transmitter 21 on a scraper 11 and transient magnetization. The driving of one or more magnets is carried out, in particular, by means of a (not drawn) hydraulic motor, which is set in rotation due to the flow of the hydraulic medium. The detector zone 22 in turn comprises a matrix with an appropriate number of magnetic field detectors 23 located side by side and one above the other, and by means of each individual magnetic field detector 23, it is possible to perform a magnetization test carried out on one side with a transmitter 21 on a scraper 11 and transient magnetization.

[0019] Fig. 3A, 3B and 3C schematically depict scoops 11 in three different positions relative to the detector zone 22. In the highest position in Fig. 3 is shown a screar 11 passing through the passage 15 between the alternating magnetic field generator 21 and the detector zone 22 from matrix-shaped magnetic field in a medium position, i.e. with normal chain tension. The individual detectors 23 of the detector zone 22 detect variations in the intensity of the magnetic field from which the average position can be calculated. The variable magnetic field emitted by the transmitter 21 and transferred to the ridge 11 is illustrated in the figure in the form of schematic lines of the magnetic field. In FIG. 3B the scraper 11 went up due to excessive chain tension. Magnetic field lines indicate that the variable magnetic field 21 generated at band 21 has moved upwards, whereby the detectors 23 of the magnetic field located above detect the maximum breaking of the field strength, while the magnetic field detectors 23 located deeper detect much lower intensities magnetic field. Since the magnetic field introduced on the comb 11 is a modulated field, it is obvious that the magnetic field detectors 23 detect magnetic field modulated according to the frequency rotation of the alternating magnetic field. However, based on a sufficiently high frequency of rotation of the alternating magnetic field during the scraper flight, a sufficient number of changes in the variable magnetic field amplitude are detected, allowing the current position of the scraper 11 to be determined confidently from the magnetisation of the scraper 11. Fig. 3C shows the state before or during the chain overhang. The ridge 11 is in the position at the lower end of the detector zone 22, so that the deepest detectors 23 of the magnetic field detect the maximum changes in the amplitudes of the alternating magnetic field introduced on the scraper 11 by the transmitter 21. The momentary magnetic field shift is represented by the different position of the magnetic field lines at transmitter 21. free from the magnetisation effect of the scoops 11. Fig. 3C shows the state before or during the chain overhang. The ridge 11 is in the position at the lower end of the detector zone 22, so that the deepest detectors 23 of the magnetic field detect the maximum changes in the amplitudes of the alternating magnetic field introduced on the scraper 11 by the transmitter 21. The momentary magnetic field shift is represented by the different position of the magnetic field lines at transmitter 21. free from the magnetisation effect of the scoops 11. Fig. 3C shows the state before or during the chain overhang. The ridge 11 is in the position at the lower end of the detector zone 22, so that the deepest detectors 23 of the magnetic field detect the maximum changes in the amplitudes of the alternating magnetic field introduced on the scraper 11 by the transmitter 21. The momentary magnetic field shift is represented by the different position of the magnetic field lines at transmitter 21.

[0020] Turning back to Fig. 1, signals emitted from the detector zone 22 for individual magnetic field detectors 23 are transmitted to the master control unit 50. Via the signal conduits 25, shown in Fig. 1, it is possible to transmit to the master control unit 50 data related to the current number of rotations of the drive motors 2 or 6. On the basis of the measured data 25 from the detector zone 22 and the current data on the number of rotations of the drive motors 2, 6 the calculation and control unit 50 can generate control signals that are transmitted to the hydraulic control 9,whereupon through the signal line 8, the extension or pulling of the hydraulic tensioning device 7 is activated in order to change the position of the sprocket 5 in the auxiliary drive to eliminate the chain overhang or to reduce the tension under too much tension of the drive chain 6. The control unit 50 can generate signals in parallel controls for drive motors 2, 6 changing the instantaneous speed of these drive motors 2, 6 to prevent overhangs or excessive chain tension.6 changing the instantaneous speed of these drive motors 2, 6 to prevent overhangs or excessive chain tension.6 changing the instantaneous speed of these drive motors 2, 6 to prevent overhangs or excessive chain tension.

The measuring principle of the sensor device 30 in the present embodiment is based on the introduction of a modulated magnetic field (variable magnetic field) on the scraper and reading by means of the detector zone 32 with a plurality of detectors 33 of the modulated magnetic field taken over by the scraper when the magnetic field generator of the alternating magnetic field is exceeded. The measuring signals of the detector zone 32 can be transmitted to the measuring and control device 50 also via the signal lines 35.

[0022] Fig. 4 is a schematic pictorial drawing of the same system technique used in plow apparatus 110 for underground mining. The mining planer 160 is driven by a substantially endless chain link 106 consisting of one and the other vertical and horizontal chain links / 112, 113, fig 5 / and moves reversibly from one drive station 101 to a second drive station 104, or vice versa. as indicated by the double arrow R in Fig. 4. The drive station 101 is equipped with unplugged drive motors and a drive wheel 105 and a tensioning device 107. Depending on the direction of travel, the drive 160 is the main drive and the other at this time is an auxiliary drive. The plow chain 106 again forms the upper compartment 106A and the lower section 106B, which - depending on the direction of travel R of the jet 116 - constitute a train compartment or a return compartment. Because the overhang of the chain and / or the high chain tension can occur both at the inlet and at the outlet of each of the sprockets 103 depending on the direction R of the plow body 160, four identical sensor devices 120 are provided for plow device 110, which are equipped with on one side in the detector zone 122 with a sufficient number of magnetically arranged magnetic field detectors 123 and located on the side of the culvert 106. Each detector zone 122 is schematically shown in Figures 5A, 5B and 5C as indicated by a variable magnetic field generator 121 located opposite the detector zone 122 and in the same way from the side of the culvert 115 for the chain link 106. Since the detectors 122 of the magnetic field introduced into the horizontal chain links 112 are detected at the plow device 110 by the detectors 123 of the detector zone 122, the distance between the detector 121 and the detector zone 122 is clearly smaller than in the previous embodiment. In addition, the generator 121 and the detector zone 122, alternatively to the machine body, can be mounted directly in the side walls of the unplugged plow box, in which the sprockets 103 or 105 are mounted to examine changes in the modulated magnetic field from a relatively secure position. Similarly to the previous embodiment, the shift of the plow chain 106 determined on the basis of the detection of the maximum amplitude of the alternating magnetic field by the higher detectors 123 of the magnetic field, as shown in FIG. 5B, or magnetic detectors 123 located deeper as shown in FIG. 5C, indicates that the chain is overstressed if it moves upwardly from the center position or the resulting chain overhang as it moves it falls down from this central position. Also in the case of the plow device 110, a control and calculation unit 150 is provided, to which all measurement values ​​of at least four detector zones 122 of the sensor devices 120 are transmitted. The signal trans- mission can be implemented with signal lines 125 or a system bus, or wirelessly via radio via a radio 126 and a radio receiver 127 (figure 4). It is understood that the radio receiver 127 may be used for bi-directional data transfer. or by magnetic field detectors 123 located deeper, as shown in Fig. 5C, indicates that the chain is overstressed if it moves upwardly from the center position or the resulting chain overhang as it moves down from this central position . Also in the case of the plow device 110, a control and calculation unit 150 is provided, to which all measurement values ​​of at least four detector zones 122 of the sensor devices 120 are transmitted. The signal trans- mission can be implemented with signal lines 125 or a system bus, or wirelessly via radio via a radio 126 and a radio receiver 127 (figure 4). It is understood that the radio receiver 127 may be used for bi-directional data transfer. or by magnetic field detectors 123 located deeper, as shown in Fig. 5C, indicates that the chain is overstressed if it moves upwardly from the center position or the resulting chain overhang as it moves down from this central position . Also in the case of the plow device 110, a control and calculation unit 150 is provided, to which all measurement values ​​of at least four detector zones 122 of the sensor devices 120 are transmitted. The signal trans- mission can be implemented with signal lines 125 or a system bus, or wirelessly via radio via a radio 126 and a radio receiver 127 (figure 4). It is understood that the radio receiver 127 may be used for bi-directional data transfer.

[0023] Magnetic sensor devices can also serve, for example, to detect chain wear or scrapers. For high reliability of detecting chain overhangs, a reference or calibration cycle can be performed after each machine tool stoppage, in which a reference value is determined for each chain link or for each horizontal chain link of the plow device or each scraper of the conveyor device. In a preferred case, the computing and control device has data on the number of horizontal links in the chain or scoops built into the system. Thanks to the reference data stored in the memory for each scraper, or each chain link, and therefore that the individual magnetic field of each scraper and each horizontal chain link changes with the increase of its consumption, on the basis of comparison of reference values ​​of the previous calibration cycle, and with longer life from comparing current values ​​with reference values ​​from the change of transmitted magnetic field when passing through a variable field magnetic generated by the transmitter it is possible to determine the current state of wear, which allows the implementation of the maintenance interval in a timely manner before the chain break or tp occurs. damage. In connection with the above, the operation of the sensor device used at the mining equipment is not limited to detecting chain overhangs. and with a longer operating time from comparing the current values ​​with the reference values ​​from the change of the transmitted magnetic field when passing through the variable magnetic field generated by the transmitter, it is possible to determine the current consumption state, allowing the maintenance interval to be implemented in a timely manner before the chain break or tp occurs. damage. In connection with the above, the operation of the sensor device used at the mining equipment is not limited to detecting chain overhangs. and with a longer operating time from comparing the current values ​​with the reference values ​​from the change of the transmitted magnetic field when passing through the variable magnetic field generated by the transmitter, it is possible to determine the current consumption state, allowing the maintenance interval to be implemented in a timely manner before the chain break or tp occurs. damage. In connection with the above, the operation of the sensor device used at the mining equipment is not limited to detecting chain overhangs. before the chain break or tp occurs. damage. In connection with the above, the operation of the sensor device used at the mining equipment is not limited to detecting chain overhangs. before a chain break occurs or tp. damage. In connection with the above, the operation of the sensor device used at the mining equipment is not limited to detecting chain overhangs.

[0024] In the embodiments, a system of alternating magnetic field generators and a detector zone has been schematically represented. The detector zone can be equipped with more than just nine or twelve magnetic field sensors, for example to increase the resolution of the system, it can contain 16 or 27 magnetic field sensors. A high efficiency long-lasting magnet (the so-called super-magnet) can be used to generate a modulated magnetic field, for example a neodymium compound with iron and boron (NdFeB) or other material suitable for making super-magnets with a sufficiently high magnetic induction, for example 1T, driven at a rotational speed, for example, up to 1000 revolutions per minute to generate a variable magnetic field with a sufficient number of amplitude changes during the flight of scrapers or chain links. The angle of rotation can be used as a reference value. The transmitter can be assigned, for example, magnetic field sensors mounted on the same side of the culvert. The state of magnetization of the scoops or chain links caused by the variable field is clearly different from the initial state of magnetization of scrapers or chain links, so that the dynamic, modulated, variable magnetic field can certainly be distinguished from the state of magnetization of the starting scraper when crossing the sensor zone. The sensor system should take measurements in at least two directions, and it is best if

[0025] FIG. 6 schematically illustrates an exemplary embodiment of a variable magnetic field generator 221 as a transmitter for a sensor device according to the invention. The magnetic field generator 221 preferably has a box-like housing 250, which can be mounted in a mounting recess located, for example, in the side of the machine body and in which a rotating shaft 240 is mounted, on which the block magnets 241 are secured with torsion resistance. The permanent magnet system, which in this case consists of block magnets 241, each possesses a magnetically compatible magnetization. In the embodiment shown, all poles marked with the letter N and all poles marked with the letter S of the block magnets 241 are each positioned one on the other with the orientation one above the other. The drive 241 and the magnets 241 connected to it are also intended for a hydraulic drive 242, coupled to a 243 gear with an output shaft 244, on which 245 is mounted, which in turn engages with another, rigidly. with a rotary shaft 240 connected by a gear 246. The hydraulic drive may consist, in particular, of a hydraulic motor with a flow regulator (not shown) for speed control. When rotation of the rotating shaft 240 on the entire height of the generator 221 of the alternating magnetic field, a dynamic alternating magnetic field is created,

[0026] The above description of the drawings refers to a mining device with a sensing device having a variable magnetic field generator as a transmitter of a dynamic magnetic field. The transmitter could also generate a static magnetic field, tested in the sensing zone of a mining device, as described above. Fig. 7 and Fig. 8 show an exemplary embodiment for such a magnetic field generator 321 that can produce a static, however, alternating magnetic field. Inside the box-shaped housing 350 on the longitudinal sides, of which - in the working mode - one faces the machine side and the other towards the drive station, the pole plates 351, 352 are located from a magnetically soft magnetizable iron material between which a magnetic package is embedded. 348, in this case, with a plurality of magnetized ring magnets 341 arranged one above the other. The ring magnets 341 are configured such that in each case all poles N lie one above the other and all poles S are each stacked on top of each other. All ring magnets 341 are mounted on one magnetic shaft 340, which by means of the diagrammatically shown in FIG. 8 and connected to it, for example by means of rotating drive gears 342, can be rotated relative to pole plates 351, 352, depending on the relative position of the magnetic package 348 in relation to the pole plates 351, 352 to introduce magnetic fields of varying intensities on these plates and on flywheels or chain links. The spinning of the magnetic shaft takes place preferably only during the calibration cycle, in contrast to which the magnetic shaft in the current operating mode is held in standstill by the disconnected rotary drive and the active reducer. The magnetic field generator 321 in the function of the transmitter of the sensor device can generate a static, non-modulated magnetic field, which on one side of the machine body is inserted on the rakes, and on the other side of the machine body is tested in the detector zone. As a result of changing the orientation of the magnetic package 348 in relation to the passage or to the detector zone, it is possible to perform the measurement each time using the optimal magnetic field. in contrast to which the magnetic shaft in the current operating mode is kept in standby by the disconnected rotary drive and the active reducer. The magnetic field generator 321 in the function of the transmitter of the sensor device can generate a static, non-modulated magnetic field, which on one side of the machine body is inserted on the rakes, and on the other side of the machine body is tested in the detector zone. As a result of changing the orientation of the magnetic package 348 in relation to the passage or to the detector zone, it is possible to perform the measurement each time using the optimal magnetic field. in contrast to which the magnetic shaft in the current operating mode is kept in standby by the disconnected rotary drive and the active reducer. The magnetic field generator 321 in the function of the transmitter of the sensor device can generate a static, non-modulated magnetic field, which on one side of the machine body is inserted on the rakes, and on the other side of the machine body is tested in the detector zone. As a result of changing the orientation of the magnetic package 348 in relation to the passage or to the detector zone, it is possible to perform the measurement each time using the optimal magnetic field. which on one side of the machine body is introduced to the raking tools, and on the other side of the machine body is tested in the detector zone. As a result of changing the orientation of the magnetic package 348 in relation to the passage or to the detector zone, it is possible to perform the measurement each time using the optimal magnetic field. which on one side of the machine body is introduced to the raking tools, and on the other side of the machine body is tested in the detector zone. As a result of changing the orientation of the magnetic package 348 in relation to the passage or to the detector zone, it is possible to perform the measurement each time using the optimal magnetic field.

[0027] The invention is not limited to the schematically shown embodiments. At least one of the drive stations could also be a non-powered turning station with a chainwheel only for turning the drive chain.