An induction switch and a front safety device for a coal mining machine

Abstract

The present invention relates to the technical field of coal mining machines, and discloses an inductive switch and a front safety device for coal mining machines, including a switch base and a signal device arranged on the switch base, wherein a liquid passage for liquid to flow through is opened in the switch base, and when liquid flows into the liquid passage, the signal device is triggered and sends a signal, and when the liquid in the liquid passage weakens or disappears, the signal device stops sending the signal. The inductive switch provided by the present invention is applied to the front safety device of the coal mining machine, and the inductive switch is started according to the liquid flowing in the pipeline for dust reduction, and is stopped according to the disappearance of the liquid, and has an accurate response, and automatically sends a start or stop inductive signal to the coal mining machine, without the need for manual participation and operation, and is efficient, accurate, and convenient to use.

Description

Technical Field

[0001] The present invention relates to the technical field of coal mining machines, and more specifically to an induction switch and a front safety device of a coal mining machine. Background Art

[0002] Before starting the coal mining machine, it is necessary to first spray water to reduce dust in the workplace. The front safety device of the coal mining machine includes a water spray dust reduction device. In the prior art, the front safety device is usually started first, and the coal mine is sprayed with water to reduce dust. Then the staff sends a signal to the coal mining machine operator and then starts the coal mining machine. During the coal mining process, it is also necessary to keep spraying water to reduce dust. If the front safety device is interrupted or stopped due to circumstances, a signal should be sent to the coal mining machine in time to stop the coal mining machine. During the whole process, if the signal transmission is carried out manually or manually, the process is cumbersome and inconvenient. Summary of the invention

[0003] The purpose of the present invention is to provide an induction switch, which is applied to the front safety device of a coal mining machine. The induction switch is activated according to the liquid flowing in the pipeline for dust reduction, and is stopped according to the disappearance of the liquid. It responds accurately and automatically sends an induction signal of starting or stopping to the coal mining machine. It does not require manual participation and operation, is efficient and accurate, and is easy to use. The purpose of the present invention is also to provide a front safety device of a coal mining machine including the induction switch.

[0004] To achieve the above-mentioned purpose, the present invention provides an inductive switch, comprising a switch base and a signal device arranged on the switch base, wherein a liquid passage for liquid to flow through is opened in the switch base, when liquid flows into the liquid passage, the signal device is triggered and sends a signal, and when the liquid in the liquid passage weakens or disappears, the signal device stops sending the signal.

[0005] Preferably, the signal device includes a signal device body for being electrically connected to a signal receiving device and a trigger component acting on the signal device body, wherein the trigger component is arranged in the liquid passage; when liquid flows into the liquid passage, the trigger component triggers the signal device body, and when the liquid in the liquid passage weakens or disappears, the trigger connection between the trigger component and the signal device body is disconnected.

[0006] Preferably, the trigger component is movably arranged in the liquid passage, and a reset structure for driving the trigger component to reset is also arranged on the switch base. When liquid flows into the liquid passage, the trigger component is pushed by the liquid and displaced to the trigger position. When the liquid in the liquid passage weakens or disappears, the trigger component returns to the original untriggered position under the action of the reset structure.

[0007] Preferably, a mobile carrier for carrying the trigger component is further included, the trigger component is wrapped inside the mobile carrier, the mobile carrier is movably arranged in the liquid passage, and the reset structure acts on the mobile carrier.

[0008] Preferably, it further comprises a fixed carrier arranged on the liquid passage, the movable carrier is movably arranged on the fixed carrier, and the reset structure comprises an elastic acting member whose two ends are respectively connected to or abutted against the movable carrier and the fixed carrier.

[0009] Preferably, the fixed carrier is provided with an avoidance through hole which is connected with the liquid passage and allows the liquid to flow through.

[0010] Preferably, the signal device body is connected to the fixed carrier, and the switch base is provided with a wiring compartment for accommodating wiring terminals and a wiring passage for wires connected to the signal device body to enter and exit the wiring compartment.

[0011] Preferably, the fixed carrier is provided with a through-shaped movable through hole for the movable carrier to penetrate, and a through-shaped anti-blocking passage is provided between the inner wall of the movable through hole and the outer wall of the movable carrier in the extending direction.

[0012] Preferably, a filter component for filtering the liquid is provided on the liquid passage.

[0013] The present invention also provides a front safety device for a coal mining machine, comprising a water spray dust reduction device and the induction switch as described above, wherein the signal device of the induction switch is used for being electrically connected to the coal mining machine.

[0014] The technical solution provided by the present application may include the following beneficial effects: In the technical solution provided by the present invention, the signal device of the induction switch operates according to the liquid in its own liquid passage, is started and generates a signal when liquid flows in, and is shut down and stops when the liquid disappears. The induction switch is applied to the front safety device of the coal mining machine. The induction switch generates signal changes according to the flow of liquid used for dust reduction in the water spray dust reduction pipeline. When the liquid flow starts to reduce dust, it is started in time and automatically sends a signal to the coal mining machine. When the liquid disappears and dust reduction stops, it is shut down in time and feedback information to the coal mining machine through this change, thereby realizing the automatic transmission of two types of signals of the coal mining machine by the front safety device, and the response is accurate and fast, efficient and precise, without manual participation and operation, and convenient to use.

[0015] The various technical effects that can be produced by the preferred technical solutions among the various technical solutions provided in this application are described in detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A schematic diagram of the internal structure of the induction switch in an embodiment of the present invention;

[0018] Figure 2 Schematic diagram of the composition of the induction switch in an embodiment of the present invention;

[0019] Figure 3 Schematic diagram of the structure of the anti-blocking passage in an embodiment of the present invention.

[0020] Figure 1-Figure 3 middle:

[0021] 1. Switch base; 11. Main body; 12. Connector; 13. Wiring compartment; 14. Liquid passage; 15. Wiring passage; 2. Fixed carrier; 21. Storage slot; 22. Avoidance through hole; 23. First through slot; 3. Mobile carrier; 31. Second through slot; 4. Trigger component; 5. Movable joint; 51. Screw pipe section; 52. Joint pipe section; 6. Elastic action member; 7. Cover; 8. Filter component. DETAILED DESCRIPTION

[0022] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0023] The purpose of this specific embodiment is to provide an induction switch, which is applied to the front safety device of the coal mining machine. The induction switch is activated according to the liquid flowing in the pipeline for dust reduction and is stopped according to the disappearance of the liquid. It responds accurately and automatically sends a start or stop induction signal to the coal mining machine. It does not require manual participation and operation, is efficient and accurate, and is easy to use. The purpose of this specific embodiment is also to provide a front safety device of the coal mining machine including the induction switch.

[0024] The following embodiments are described in detail with reference to the accompanying drawings. In addition, the embodiments shown below do not limit the content of the invention described in the claims. In addition, the entire content of the structure represented by the following embodiments is not limited to the solution required as the invention described in the claims.

[0025] Please refer to the attached Figure 1-3 The present embodiment provides an induction switch, which includes a switch base 1 and a signal device arranged on the switch base 1. A liquid passage 14 for liquid to flow through is provided in the switch base 1. When liquid flows into the liquid passage 14, the signal device is triggered and sends a signal. When the liquid in the liquid passage 14 weakens or disappears, the signal device stops sending the signal. That is, the signal device of the induction switch operates according to the liquid in its own liquid passage 14. It is activated and generates a signal when liquid flows in, and it is shut down and stops when the liquid disappears. The induction switch is applied to the front safety device of the coal mining machine. The signal device is connected to the coal mining machine through a wire, and the liquid passage 14 is connected to the water spray dust suppression pipeline. When the front safety device is activated and the liquid used for dust reduction flows into the pipeline and into the liquid passage 14, the signal device of the induction switch is triggered, the induction switch is activated, and the signal is transmitted to the coal mining machine. The staff at the coal mining machine can start the coal mining machine according to the signal or the controller can automatically start the coal mining machine according to the signal; when the water spray dust reduction equipment is automatically shut down due to a problem or is manually shut down due to need, the liquid in the pipeline is weakened and even disappears, the liquid in the induction switch liquid passage 14 is weakened or disappears, the signal device stops generating signals, and the induction switch is disconnected. The staff at the coal mining machine or the controller is informed of the signal change and can shut down the coal mining machine in time.

[0026] So configured, the induction switch provided in this embodiment generates signal changes according to the flow of liquid used for dust reduction in the water spray dust reduction pipeline. When the dust reduction work starts due to the flow of liquid, it is promptly started and automatically sends a signal to the coal mining machine. When the dust reduction stops due to the disappearance of the liquid, it is promptly shut down and feedback information is given to the coal mining machine through this change, thereby realizing the automatic transmission of two types of signals from the front safety device to the coal mining machine. No manual participation or any switch operation is required throughout the process. The application is convenient, which provides great convenience for coal mine work. At the same time, it also improves the safety of the staff, and is triggered to start according to the dust reduction liquid, with fast response, efficiency and accuracy. On the other hand, the induction switch itself is provided with a liquid passage 14 for connecting to the pipeline. The signal device generates a signal operation through the flow of liquid in the liquid passage 14, and will not be mistakenly triggered by other conditions, and the response is accurate.

[0027] As shown in the drawings, two liquid passages 14 and two groups of signal devices can be arranged on the switch base 1. The two liquid passages 14 are arranged side by side and are both used to access the pipeline. They can be connected to the same pipeline and flow in the same direction. The two groups of signal devices act synchronously to enhance signal transmission. At the same time, if one of them fails, the other can ensure that it continues to work normally, thereby enhancing durability.

[0028] The two liquid passages 14 can also be connected to different pipelines respectively, such as one is connected to the pipeline for spraying liquid and the other is connected to the pipeline for liquid return. The two sets of signal devices can respectively provide sensing feedback on the spraying and return of liquid, thereby enhancing the detection and security of the device usage status.

[0029] The signal device of the induction switch can be a liquid induction sensor in the prior art, such as a non-metallic induction switch, a flow sensor, a liquid level sensor, etc. Alternatively, the signal device can also include a signal device body for electrical connection with a signal receiving device and a trigger component 4 acting on the signal device body, wherein the trigger component 4 is arranged in the liquid passage 14; when liquid flows into the liquid passage 14, the trigger component 4 is triggered by the inflow of liquid and the signal device body is triggered; when the liquid in the liquid passage 14 weakens or disappears, the trigger connection between the trigger component 4 and the signal device body is disconnected.

[0030] Specifically, the trigger component 4 is movably arranged in the liquid passage 14, and a reset structure for driving the trigger component 4 to reset is also arranged on the switch base 1. When liquid flows into the liquid passage 14, the trigger component 4 is pushed by the liquid and moves to the trigger position. When the liquid in the liquid passage 14 weakens or disappears, the trigger component 4 returns to the original untriggered position under the action of the reset structure. In the preferred embodiment, if Figure 1 As shown, the displacement direction of the trigger component 4 is the same as the extension direction of the liquid passage 14, that is, the flow direction of the liquid, and the reset structure may include an elastic reset member.

[0031] In order to prevent the trigger component 4 from being directly soaked in liquid and damaged, in this embodiment, the induction switch also includes a mobile carrier 3 for carrying the trigger component 4, and the trigger component 4 is wrapped inside the mobile carrier 3. The mobile carrier 3 can be movably arranged in the liquid passage 14. When liquid flows into the liquid passage 14, the mobile carrier 3 is impacted by the water flow and moves with the trigger component 4 to the trigger position. When the liquid in the liquid passage 14 weakens or disappears, the mobile carrier 3 returns to the original untriggered position under the action of the reset structure. Such a setting strengthens the protection of the trigger component 4, and at the same time, it also reduces the use requirements of the trigger component 4, which can expand the types of signal devices.

[0032] The mobile carrier 3 may be directly connected to the inner wall of the liquid passage 14, or, as Figure 1 As shown, the induction switch also includes a fixed carrier 2 arranged on the liquid passage 14, and a movable carrier 3 is movably arranged on the fixed carrier 2. The fixed carrier 2 and the liquid passage 14 extend in the same direction, and the two ends of the elastic acting member 6 of the reset structure are respectively connected to or abutted against the movable carrier 3 and the fixed carrier 2.

[0033] It can be that the cross section of the fixed carrier 2 is smaller than the cross section of the liquid passage 14, the fixed carrier 2 does not block the liquid passage 14, and a gap is left between the two for the liquid to flow through; or, the outer wall of the fixed carrier 2 is connected to the inner wall of the liquid passage 14 and blocks the liquid passage 14. The fixed carrier 2 is also provided with an avoidance through hole 22 that is connected to the liquid passage 14 and allows the liquid to flow through. There can be multiple avoidance through holes 22, all of which are through-shaped along the extension direction of the fixed carrier 2. The fixed carrier 2 can be connected to the switch base 1 by an interference fit, or fixed to the switch base 1 by fasteners such as screws or screws. The fixation of the fixed carrier 2 can ensure the accurate displacement of the movable carrier 3.

[0034] The movable carrier 3 directly penetrates into the movable through hole of the fixed carrier 2 and slides. The movable carrier 3 can be set in a tubular column shape. The movable through hole can be through-shaped. The elastic action member 6 is sleeved on the movable carrier 3, one end of which is against the movable carrier 3 through the blocking boss protruding on the movable carrier 3 or connected to the movable carrier 3 through a fixed pin, and the other end is against the fixed carrier 2. The fixed carrier 2 is provided with a sink groove for the end of the elastic action member 6 to be embedded and abutted. Figure 1 As shown, the movable carrier 3 penetrates the fixed carrier 2, one end of which is located on the upstream side of the fixed carrier 2 to receive the thrust of the liquid, and the other end is located on the downstream side of the fixed carrier 2 and is sleeved with an elastic acting member 6, which is configured as a compression spring.

[0035] The movable carrier 3 and the fixed carrier 2 are nested and relatively slidably arranged. If impurities in the liquid, such as mud and sand, are stuck in the gap between the two, it will cause blockage or jamming, affecting the normal movement of the movable carrier 3 and causing the induction switch to malfunction. Figure 3 As shown, the movable through hole is through-connected along the extension direction of the fixed carrier 2, and an anti-blocking passage for passing impurities such as mud and sand is provided between the outer wall of the movable carrier 3 and the inner wall of the movable through hole, and the anti-blocking passage is also through-connected along the extension direction of the two.

[0036] Specifically, the diameter of the movable through hole on the fixed carrier 2 is larger than the diameter of the movable carrier 3. Furthermore, a through groove is provided on at least one of the fixed carrier 2 and the movable carrier 3. Figure 3 As shown, a first through groove 23 extending in the axial direction is provided on the inner wall of the movable through hole of the fixed carrier 2, and a second through groove 31 extending in the axial direction is provided on the outer wall of the movable carrier 3. The provision of the first through groove 23 and the second through groove 31 increases the gap between the movable through hole and the movable carrier 3, effectively avoiding the jamming and blocking of impurities such as mud and sand, and ensuring the smooth and stable displacement of the movable carrier 3.

[0037] The fixed carrier 2 and the movable carrier 3 can both be connected to the elastic member action member 6: for example, the end of the movable carrier 3 located outside the fixed carrier 2 is provided with a hoop shaft section that abuts against the inner wall of the compression spring to allow the compression spring to be firmly sleeved; and the diameter of the sunken groove on the fixed carrier 2 for the compression spring to be embedded and abut against is matched with the outer diameter of the compression spring, and the groove wall abuts against the outer wall of the compression spring to prevent the compression spring from escaping from the sunken groove. In this way, through the connection of the two ends of the compression spring located in the middle, the compression spring can be prevented from escaping from the fixed carrier 2 or the movable carrier 3, and the movable carrier 3 can also be prevented from excessive displacement when returning to its original position, thereby enhancing stability.

[0038] The trigger component 4 is wrapped inside the mobile carrier 3 , and the mobile carrier 3 is provided with a cavity or a countersunk hole to accommodate the trigger component 4 , and the opening of the cavity or the countersunk hole is blocked by a blocking head.

[0039] The signaler body can be arranged on the switch base 1, or can be connected to the fixed carrier 2, and the switch base 1 is provided with a wiring compartment 13 for accommodating the wiring terminals connected to the signaler body, and the switch base 1 is also provided with a wiring passage 15 for the wires connected to the signaler body to enter and exit the wiring compartment 13. Figure 1 As shown, the wiring compartment 13 is arranged in the middle area of ​​the two liquid passages 14 on the switch base 1, and a receiving groove 21 for accommodating the main body of the signal device is arranged on the side of the fixed carrier 2, and the notch of the receiving groove 21 faces the wiring compartment 13. The wiring passage 15 on the switch base 1 connects the notch of the receiving groove 21 with the wiring compartment 13, which is equivalent to opening a window on the side wall of the wiring compartment 13. The signal device can be a magnetically controlled switch, and the magnet of the magnetically controlled switch forms the trigger component 4, and the reed switch part forms the main body of the signal device. The magnet is arranged on the mobile carrier 3. When impacted by the water flow, the mobile carrier 3 is pushed and displaced. When the compression spring is compressed at the same time, the displacement stops, and the magnet moves to a position opposite to the reed switch. By adsorbing the reed switch, the induction switch is turned on, and the start signal is transmitted to the coal mining machine through the wire. When the water flow weakens or stops flowing or disappears, the compression spring pushes the magnet to leave the adsorption position, the magnet is disconnected from the reed switch, and the electrical signal transmitted by the induction switch at the coal mining machine disappears, and this change transmits the shutdown signal.

[0040] Of course, the signal device can also be other switch structures, such as a proximity switch. If it is set as a metal proximity switch, the metal sheet forms the trigger component 4, the sensing body of the switch forms the signal device body, the movable carrier 3 and the fixed carrier 2 are both set to non-metallic materials, and the elastic acting member 6 is set on the upstream side of the trigger component 4 and is not within the sensing range.

[0041] Alternatively, the signal device's signal body is set as a push switch, and the trigger component 4 is a push block-type component. The connection position of the push switch is downstream of the off position. In the initial position, it is in the off state. One end of the button's connection position is tilted. The trigger component 4 moves through the off position to press down the tilted connection end of the button, and the switch is turned on. At the same time, the off end of the button is tilted. When the trigger component 4 returns to its position, the off end is pressed down to cause the connection end to tilt.

[0042] The opening of the wiring compartment 13 is sealed by the cover 7, and the cover 7 and the opening of the wiring compartment 13 can be opened and closed. Specifically, the cover 7 can be connected and opened and closed by fasteners, and a sealing ring or a sealing gasket is provided between the cover 7 and the opening.

[0043] In order to prevent the impurities in the liquid from damaging the induction switch, in this embodiment, a filter component 8 for filtering the liquid is provided on the liquid passage 14 of the induction switch. In a preferred embodiment, the filter component 8 is located upstream of the mobile carrier 3. The filter component 8 can be a filter net or filter cotton, etc. The filter component 8 is detachably connected to the switch base 1 through a snap structure or fasteners such as screws to facilitate later replacement.

[0044] To facilitate the removal and replacement of the filter component 8, the switch base 1 includes a main body 11 and a connector 12 connected to both ends of the main body 11 along the extension direction of the liquid passage 14. The connector 12 is detachably connected to the main body 11, and the filter component 8 is installed on the end attachment of the main body 11 or the end attachment of the connector 12.

[0045] Since the switch base 1 is to be connected to the pipeline, both ends of the switch base 1 can be connected with a movable joint 5, which is detachably connected to the switch base 1 through a threaded structure or a snap-fit ​​structure, and the movable joint 5 is also provided with a connection structure detachably connected to the pipeline. The connection structure can be a threaded connection, a plug-in connection, a snap-fit ​​connection, or a fastened connection. One side of the connector 12 of the switch base 1 is connected to the main body 11, and the other side is connected to the movable joint 5. The movable joint 5 includes a screwing pipe section 51 connected to the connector 12 and a joint pipe section 52 connected to the screwing pipe section 51.

[0046] This embodiment also provides a front safety device for a coal mining machine, including a water spray dust reduction device and the induction switch as described in the above embodiments, and the signal device of the induction switch is used to be electrically connected to the coal mining machine. A controller is provided on the coal mining machine, and the signal device of the induction switch is connected to the controller. The front safety device for the coal mining machine provided in this embodiment has the function of automatically transmitting two types of signals, start or shut down, to the coal mining machine, without the need for manual participation, and is easy to use. The transmission of the signal is efficient and accurate, and the response is timely, which provides great convenience and safety for coal mine work. The derivation process of this beneficial effect is generally similar to the derivation process of the beneficial effect brought about by the above-mentioned induction switch, and will not be repeated in this article.

[0047] It should be noted that the words "first", "second" and the like described herein are not intended to limit a specific order, but are merely used to distinguish between various components or functions. The words "horizontal", "vertical", "up", "down", "left" and "right" described herein refer to the induction switch when it is in a natural placement state.

[0048] It is understood that the same or similar parts in the above embodiments can refer to each other, and the content not described in detail in some embodiments can refer to the same or similar content in other embodiments. The multiple solutions provided by the present invention include the basic solution itself, which are independent of each other and do not restrict each other, but they can also be combined with each other without conflict to achieve multiple effects together.

[0049] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A front safety device for a coal mining machine, characterized in that: It includes a water spray dust suppression device and an induction switch, wherein the signal device of the induction switch is used to be electrically connected to the coal mining machine; The inductive switch comprises a switch base (1) and a signal device arranged on the switch base (1); a liquid passage (14) for liquid to flow through is provided in the switch base (1); when liquid flows into the liquid passage (14), the signal device is triggered and sends a signal; when the liquid in the liquid passage (14) decreases or disappears, the signal device stops sending the signal; The signal device comprises a signal device body for being electrically connected to a signal receiving device and a trigger component (4) acting on the signal device body, wherein the trigger component (4) is arranged in the liquid passage (14); when liquid flows into the liquid passage (14), the trigger component (4) triggers the signal device body; when the liquid in the liquid passage (14) weakens or disappears, the trigger connection between the trigger component (4) and the signal device body is disconnected; The trigger component (4) is movably arranged in the liquid passage (14), and a reset structure for driving the trigger component (4) to reset is also arranged on the switch base (1); when liquid flows into the liquid passage (14), the trigger component (4) is pushed by the liquid to move to a trigger position; when the liquid in the liquid passage (14) decreases or disappears, the trigger component (4) returns to an original non-triggered position under the action of the reset structure; The inductive switch further comprises a movable carrier (3) for carrying the trigger component (4), the trigger component (4) being wrapped inside the movable carrier (3), the movable carrier (3) being movably arranged in the liquid passage (14), and the reset structure acting on the movable carrier (3); The inductive switch further comprises a fixed carrier (2) arranged on the liquid passage (14), the movable carrier (3) being movably arranged on the fixed carrier (2), and the reset structure comprising an elastic acting member (6) having two ends respectively connected to or abutting against the movable carrier (3) and the fixed carrier (2); Both ends of the switch base (1) are connected to movable joints (5), the movable joints (5) are detachably connected to the switch base (1) via a threaded structure or a snap-fit ​​structure, and a connection structure detachably connected to a pipeline is also provided on the movable joint (5).

2. The front safety device of the coal mining machine according to claim 1, characterized in that: The fixed carrier (2) is provided with an avoidance through hole (22) which is connected to the liquid passage (14) and allows liquid to flow through.

3. The front safety device of the coal mining machine according to claim 1, characterized in that: The signal device body is connected to the fixed carrier (2), and the switch base (1) is provided with a wiring compartment (13) for accommodating wiring terminals and a wiring passage (15) for wires connected to the signal device body to enter and exit the wiring compartment (13).

4. The front safety device of the coal mining machine according to claim 2, characterized in that: The fixed carrier (2) is provided with a through-shaped movable through hole for the movable carrier (3) to penetrate, and an anti-blocking passage is provided between the inner wall of the movable through hole and the outer wall of the movable carrier (3) in a through-shaped manner along the extension direction.

5. The front safety device of the coal mining machine according to claim 1, characterized in that: The liquid passage (14) is provided with a filter component (8) for filtering the liquid.

Images