Underground coal mine roof settlement monitoring device

Abstract

The invention relates to a coal mine underground roof settlement monitoring device, and belongs to the technical field of underground roof settlement monitoring, a plurality of layers of detection plates are arranged in a fixed cylinder of the device at intervals in the axial direction of the fixed cylinder, all the detection plates in each layer are arranged in an annular array, and when each detection plate extends out of the fixed cylinder to a set length, the detection plates are arranged in the fixed cylinder. The detection conductor is used as a guide and vertically slides down along a corresponding strip hole formed in the side wall of the fixed cylinder; the bottom end of the detection conductor is connected with one end of a breakpoint in a detection circuit, the detection plate is connected with the other end of the breakpoint, when the detection plate slides down to the corresponding position on the detection conductor, the part between the detection plate and the bottom end of the detection conductor is connected to the detection circuit, and the detection circuit can detect the voltage or current of the connected detection conductor; the voltage or the current is used for representing the sinkage of the top plate. According to the invention, more timely and accurate settlement monitoring of the top plate can be automatically and reliably realized.

Description

Technical Field

[0001] The invention relates to the technical field of roof settlement observation in a mine, and in particular to a roof settlement monitoring device in a coal mine. Background Art

[0002] The underground roof of a coal mine does not refer to a man-made plate, but a specific geological structure. It mainly refers to the rock and soil layer located a certain distance above the coal seam, which mainly includes three parts: pseudo roof, direct roof and old roof. The underground roof of a coal mine is an important geological structure in the process of coal mining. It has a direct impact on the safe production and working environment of coal mines. The management and control of the roof is an important part of the safe production of coal mines, because roof accidents are the most common type of coal mine safety accidents, which usually lead to casualties and equipment damage. Common roofs include pseudo roofs, which are located above the coal seam and are an extremely unstable rock layer with a thickness of generally less than 0.5 meters. They are extremely easy to collapse and usually collapse as mining progresses. False roofs only exist in some coal seams, not all coal seams, and are considered to be a safety hazard. The direct roof in the roof is located above the coal seam or pseudo roof, has a certain stability, and is generally between 1 and 2 meters thick. It is composed of shale, siltstone, etc., and is relatively not as hard as ordinary rocks. The direct roof usually has a certain mechanical strength. It is likely to collapse on its own with the completion of the coal mining face frame shifting or column return process. Therefore, it is also worth noting during coal mining. As for the old roof, it is mainly located above the direct roof or coal seam. It is a relatively thick and relatively strong rock layer. Under normal circumstances, it is difficult to collapse on its own. For example, some old roofs will collapse on their own after hanging above the goaf for a period of time, when the overhanging area of ​​the goaf is large.

[0003] Therefore, in view of the possible risk of roof collapse in coal mines, it must be closely monitored in daily production to grasp the settlement of the roof in real time. The management and control of the roof in coal mines is of great significance for preventing roof accidents and ensuring safe production in coal mines.

[0004] At present, the basic structure diagram of the special detection equipment used for the settlement monitoring of the roof in coal mines is as follows: Figure 6As shown, the anchor claw is installed in the drilled mounting hole. The sinking of the underground top plate changes the position of the anchor claw connected in the mounting hole, that is, it sinks with the top plate, thereby pulling the corresponding steel wire. The end of the steel wire is connected to a coil spring, and the roller of the coil spring rotates, thereby driving a scale to move, and at the same time driving a coaxial potentiometer to rotate, so that the output signal of the potentiometer is amplified and converted and displayed. When in use, use a mounting rod to push the first anchor claw 23 to the top of the drilled mounting hole, and then gently pull a steel wire until it feels tight. Then, in the same way, install the second anchor claw 24 at the set depth position of this mounting hole, insert the guide tube 22 axially into this mounting hole, fix the guide tube 22, straighten the steel wire, and then tighten the screws on the guide tube 22 to achieve the purpose of fixing the steel wire. At present, this type of monitoring equipment is basically the same, and the structural principle is roughly the same, so I will not go into details. However, as far as the anchor claws are used as direct monitoring elements, there are at least the following problems: First, in use, the two anchor claws are clamped and installed by squeezing contact with the inner wall of the installation hole, which is easy to be installed loosely; second, the installation depth of the anchor claws is not easy to determine, and it relies heavily on manual experience. It mainly relies on the primitive and rough manual installation of the rod to push it into place, which cannot be determined intuitively; third, there are only two sampling points in essence, and it is impossible to sample at multiple points and accurately monitor, and it is easy to have lag. Therefore, the existing underground roof settlement monitoring equipment is not only cumbersome to operate, but also has poor installation firmness and accuracy, and the monitoring results have a certain lag, and the monitoring results are one-sided due to the singleness of the data. Therefore, both reliability and the timeliness and accuracy of monitoring need to be improved. Summary of the invention

[0005] In view of this, the purpose of the present invention is to provide a coal mine underground roof settlement monitoring device to solve the problems of the prior art in coal mine underground roof settlement monitoring, such as cumbersome operation, insufficient installation stability and reliability, and poor monitoring timeliness and accuracy.

[0006] The present invention is achieved through the following technical solutions:

[0007] A coal mine underground roof settlement monitoring device, comprising a fixed cylinder for fixing in a mounting hole, wherein a plurality of detection plates are arranged in the fixed cylinder at intervals along the axial direction thereof, wherein each layer of detection plates is slidably installed along the radial direction of the fixed cylinder, and all detection plates of each layer are arranged in a ring array; when each detection plate is extended out of the fixed cylinder to a set length, it is just sleeved on a rod-shaped detection conductor, and the detection conductor is arranged parallel to the axial direction of the fixed cylinder, so that the detection plate extended out of the fixed cylinder and inserted into the roof can slide vertically along the corresponding strip hole opened in the side wall of the fixed cylinder with the detection conductor as a guide when the roof settles;

[0008] The bottom end of the detection conductor is connected to one end at a breakpoint in a detection circuit, and the detection board is connected to the other end at the breakpoint. When the detection board slides down to the corresponding position on the detection conductor, the part between the detection board and the bottom end of the detection conductor is connected to the detection circuit. The detection circuit can measure the voltage or current of the connected detection conductor, and the voltage or current is used to characterize the sinking amount of the top plate.

[0009] Furthermore, the detection plate realizes axial sliding through a plurality of hydraulic rods or electric push rods radially installed in the fixed cylinder, and all the hydraulic rods or electric push rods move synchronously in telescopic manner.

[0010] Furthermore, the upper surface of the detection plate has a planar thread, and the upper surface of each layer of the detection plate is meshed with a corresponding planar thread ring, the planar thread ring is coaxially rotatably installed in the fixed tube, and all the planar thread rings are coaxially fixed on the same driving shaft through their own several connecting rods, the driving shaft is coaxially rotatably installed in the fixed tube, and its bottom end extends out of the fixed tube and can be connected to an external driving element to achieve self-rotation; the top surface of the detection conductor is used to support the lower surface of the detection plate and slide with it.

[0011] Furthermore, a plurality of journals are provided on the driving shaft. In a non-working state, one end of the detection plate contacts and engages with the journal, and the other end thereof is flush with the surface of the fixing tube.

[0012] Furthermore, the detection conductor includes an insulating core rod, on which a resistance wire is spirally wound along its length direction, and two adjacent turns of the resistance wire do not contact each other. The bottom end of the resistance wire is connected to one end at the breakpoint, and the part where the resistance wire contacts the sliding hole on the detection plate is used to connect to the other end at the breakpoint.

[0013] Furthermore, the bottom end of the sliding hole is a trumpet-shaped structure, the top end of the detection conductor has a rounded corner, and when the planar threaded ring is rotated to the limit, the detection plate just slides out to the position of the insulating core rod directly below the sliding hole.

[0014] Furthermore, the bottom end of the detection conductor is vertically fixed on the upper end face of the planar threaded ring opposite thereto, and the drive shaft can move axially upward when the detection plate slides out to a set length, so that the upper end of the detection conductor can be axially slidably inserted into the corresponding sliding hole.

[0015] Furthermore, a positioning shoulder is fixed on a section of the driving shaft extending out of the bottom end of the fixed cylinder, and a pressure spring is sleeved between the positioning shoulder and the bottom end of the fixed cylinder. The pressure spring always tends to push the positioning shoulder downward so that the planar threaded ring and the detection plate in a non-working state maintain a meshing transmission relationship. When the bottom end of the driving shaft is pushed upward, all the planar threaded rings are separated from the detection plate, and the detection conductor moves upward and is inserted into the corresponding sliding hole.

[0016] Furthermore, a threaded sleeve with a threaded outer surface is coaxially provided on the outside of the pressure spring, the threaded sleeve is coaxially fixed to the bottom end of the fixed cylinder, a locking screw sleeve is threadedly matched with the outer surface of the threaded sleeve, a plane bearing is coaxially provided at the bottom end of the locking screw sleeve, the plane bearing is in contact with the end face of the positioning shoulder, and a hand wheel is coaxially fixed to the outside of the locking screw sleeve.

[0017] Furthermore, the fan-shaped plate structure of the detection plate has a large end side for inserting into the top plate.

[0018] The beneficial effects of the present invention are:

[0019] The underground coal mine roof settlement monitoring device uses multi-layer detection plates for embedded monitoring. Firstly, it has multi-layer detection plates, which can monitor multiple depths in real time, and each layer has several detection plates, so data collection is more comprehensive, timely and accurate.

[0020] In addition, the detection plate is mechanically inserted into the top plate. Once inserted, it is not easy to fall off automatically during subsequent use. It has extremely high reliability, and the data can directly reflect the settlement range based on the corresponding voltage or current value. It has a simple structure and a high degree of automation and accuracy in monitoring. Once the anchor claw of traditional equipment is stuck in the installation hole, it is difficult to pull it out. Once pulled out, it is easy to be damaged and has certain limitations in reuse. However, as long as there is no serious collapse-type settlement, this monitoring device has the possibility of recycling, that is, the drive shaft can be reversed to retract the detection plate, and then the fixed tube can be pulled out to achieve recycling. The detection plate will not be as easily damaged as the anchor claw; even if it sinks to a certain extent, the drive shaft can be pulled down to restore the threaded engagement between the flat threaded ring and the detection plate, and then reversed and retracted into the fixed tube for overall pull-out.

[0021] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A partially cutaway front view of the present invention;

[0023] Figure 2 It is a front view of the present invention;

[0024] Figure 3 A schematic diagram of the structure of the detection plate of the present invention when it is in sliding plug-in contact with the detection conductor;

[0025] Figure 4 Another structural schematic diagram of the detection plate of the present invention when it is in sliding plug-in contact with the detection conductor;

[0026] Figure 5 A top view of a specific structure of the detection board of the present invention;

[0027] Figure 6 It is a schematic diagram of the structural principle of existing monitoring equipment.

[0028] In the figure: a fixed cylinder 1, a detection plate 2, a detection conductor 3, an insulating core rod 301, a resistance wire 302, a plane threaded ring 4, a connecting rod 5, a drive shaft 6, a journal 7, a sliding hole 8, a bar hole 9, a positioning shoulder 10, a plane bearing 11, a hand wheel 12, a pressure spring 13, a threaded sleeve 14, a locking screw sleeve 15, a conductive sleeve 16, an indicator 21, a guide tube 22, a first measuring point 23, a second measuring point 24, and a top plate 25 to be measured underground. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0032] See also Figure 1-2The structure shown in the figure, the present invention provides a technical solution: a coal mine underground roof settlement monitoring device, the main structure includes: a fixed tube 1 used to be fixed in a pre-drilled installation hole, like the existing detection equipment, it is necessary to drill a hole in advance at the part to be tested, the installation hole is used to install the detection device, the size of the hole is designed according to the adaptability required, the fixed tube 1 can be fixed in the installation hole by all existing fixing rods or tubes, for example, a flange is set at the top of the fixed tube 1, a number of anchor rods are installed, inserted into the flange hole, and then fixed at the bottom of the installation hole or other depth positions, or concrete can be directly poured at the bottom of the installation hole to fix the fixed tube 1 in a basic manner, or other adaptively selected methods, therefore, the specific installation hole construction operation and the pre-fixed installation process of the fixed tube 1 are not repeated in this embodiment. In this embodiment, the most critical point is that the fixed tube 1 is provided with multiple layers of detection plates 2 at intervals along its axial direction, for example, 4 detection plates 2 are provided in one layer, each extending in the four directions of front, back, left, and right, respectively detecting the roof settlement state in the four directions. Specifically, in this embodiment, each layer of detection plates 2 is preferably installed in a radially sliding manner along the fixed cylinder 1, that is, telescopically installed, and all detection plates 2 of each layer are arranged in a ring array to better disperse detection; and more specifically, these detection plates 2 are processed as follows Figure 5 The fan-shaped plate structure shown in the figure has a large end for inserting into the top plate, so that it can be better plugged into the top plate as a whole, increasing the force-bearing area. During use, when each detection plate 2 extends outward from the fixed tube 1 to a set length, that is, when it is inserted into the top plate to a certain depth and integrated with the top plate, Figure 3-4, this detection board 2 is just sleeved on a rod-shaped detection conductor 3, and these detection conductors 3 are arranged parallel to the axial direction of the fixed tube 1, so that after these detection boards 2 extend out of the fixed tube 1 and are inserted into the top plate, when the top plate sinks, these detection boards 2 in a free state will inevitably sink or move down, and move down in a straight line guided by the detection conductor 3, and then slide down vertically stably under the guidance of the corresponding bar holes 9 opened on the side wall of the fixed tube 1, so as to intuitively reflect the sinking state of the top plate. At the same time, based on the above structural design, the bottom end of the detection conductor 3 in this embodiment is to be connected to one end at a breakpoint in a detection circuit, and the detection board 2 is to be connected to the other end at the breakpoint accordingly, which is equivalent to cutting off a section of the above detection conductor 3 and putting it into the breakpoint, so that the detection circuit is closed. In other words, when the detection plate 2 slides down to the corresponding position on the detection conductor 3, the part between the detection plate 2 and the bottom end of the detection conductor 3 is naturally connected to the detection circuit. In practice, this detection circuit can measure the voltage of the connected detection conductor 3, or measure its corresponding current. Then the voltage or current on the detection conductor 3 indirectly reflects the specific position of the above-mentioned detection plate 2. These parameters can be used to characterize the amount of sinking of the top plate, thereby realizing intuitive and automatic detection of the amount of sinking of the top plate.

[0033] In this embodiment: the detection plates 2 mentioned are realized by hydraulic rods or electric push rods. Specifically, these hydraulic rods or electric push rods are radially installed in the fixed tube 1. When they are extended or retracted respectively, they automatically slide. When all the hydraulic rods or electric push rods are extended or retracted synchronously, all the detection plates 2 are automatically inserted into the detection positions at different depths of the top plate.

[0034] The above synchronous movement of the detection plate 2 requires the arrangement of more hydraulic pipelines or cables. In order to simplify the structure, Figure 1-2 As shown, in this embodiment, the upper surface of the detection plate 2 has a plane thread, and the upper surface of each layer of the detection plate 2 is meshed with a corresponding plane thread ring 4, and the plane thread ring 4 is coaxially rotatably installed in the fixed tube 1, and at the same time, these plane thread rings 4 can also move axially for a certain distance. In use, all the plane thread rings 4 are coaxially fixed on the same driving shaft 6 through their respective connecting rods 5, so that by driving this special driving shaft 6, all the plane thread rings 4 can be synchronously rotated for a set number of circles, so that all the detection plates 2 can be inserted at different top plate depths. Specifically, this driving shaft 6 is coaxially rotatably installed in the fixed tube 1, and its bottom end extends out of the fixed tube 1 and can be connected to an external driving element, such as a motor main shaft in the outside world, so as to realize the in-situ rotation of the driving shaft 6; at the same time, it is also required that the top surface of the detection conductor 3 is used to support the lower surface of the detection plate 2 to realize the sliding installation of the detection plate, that is, to allow the detection plate 2 to be installed in cooperation with the sliding contact.

[0035] In this embodiment, in order to increase the length of the detection plate 2 as much as possible, Figure 1 As shown, the drive shaft 6 is provided with a plurality of journals 7 , which are obviously thinner than the rest of the drive shaft 6 . In the non-working state, one end of the detection plate 2 is in contact with the journal 7 , and the other end thereof is flush with the surface of the fixed cylinder 1 .

[0036] In this embodiment, the detection conductor 3 may be a separate conductor with a certain resistivity, or may be a structure as follows: Figure 1-2 and Figure 3-4 As shown, the detection conductor 3 includes an insulating core rod 301, and a resistance wire 302 is spirally wound on the outer surface of the insulating core rod 301 along its length direction. The two adjacent turns of the resistance wire 302 do not contact each other to avoid mutual conduction. Specifically in practice, the bottom end of the resistance wire 302 can be connected to one end at the breakpoint, and the part of the resistance wire 302 that contacts the sliding hole 8 on the detection plate 2 is used to connect to the other end at the breakpoint, so that the corresponding length segment of the resistance wire 302 is connected to the circuit to detect the current or voltage corresponding to the resistance wire 302. It should be noted that since the sliding hole 8 of the detection plate 2 is sleeved with the resistance wire, there is usually more than one circle of the resistance wire 302 in contact with the inner wall of the sliding hole 8, preferably about 3 circles, which not only avoids the poor contact that may exist when there is one circle, but also avoids the disadvantage of large errors when there are too many circles in contact. In order to facilitate the sliding sleeve connection with the detection conductor 3, as shown Figure 1 As shown, the bottom end of the slide hole 8 is a trumpet-shaped structure, and the top end of the detection conductor 3 has a rounded corner. During use, when the plane threaded ring 4 is rotated to the limit, that is, when it is rotated to the set number of revolutions, the detection plate 2 just slides out to the position where the slide hole 8 is directly opposite to the insulating core rod 301 below it. Subsequently, as long as the top plate sinks, the detection plate 2 will be sleeved on the detection conductor 3 under the guidance of the bar hole 9 on the side wall of the fixed cylinder 1. As for the specific position of the sleeve on the detection conductor 3, it represents the amplitude of the top plate sinking.

[0037] In this embodiment: Figure 1 , the bottom end of the detection conductor 3 is vertically fixed on the upper end surface of the plane threaded ring 4 opposite to it, and the driving shaft 6 can be axially moved upward by a displacement when the detection plate 2 slides out to the set length, that is, when the sliding hole 8 is opposite to the detection conductor 3, so that the upper end of the detection conductor 3 can be accurately and quickly axially slidably inserted into the corresponding sliding hole 8, so that in the detection part where the top plate has not settled, the sliding sleeve connection between the detection plate 2 and the detection conductor 3 is maintained, avoiding the initial matching relationship of the corresponding components being affected by some unknown accidental factors during long-term placement, resulting in the top plate settling in the subsequent detection at a certain moment, and the sliding hole 8 of the detection plate 2 may not be able to align with the detection conductor 3 for sleeve matching, thereby causing the problem of detection failure.

[0038] In this embodiment: In order to realize a series of driving actions of the drive shaft 6, such as Figure 1 As shown, a section of the drive shaft 6 extending out of the bottom end of the fixed cylinder 1 is fixed with a positioning shoulder 10, and a pressure spring 13 is sleeved between the positioning shoulder 10 and the bottom end of the fixed cylinder 1. The pressure spring 13 always tends to push the positioning shoulder 10 downward. Combined with factors such as the dead weight of the plane threaded ring 4, the plane threaded ring 4 in a non-working state can always maintain a meshing transmission relationship with the detection plate 2, that is, the two do not disengage. Then, in subsequent use, when the bottom end of the drive shaft 6 is pushed upward, all the plane threaded rings 4 are separated from the detection plate 2 at the same time, and when the drive shaft 6 is pressed upward or pushed to the limit, the detection conductor 3 moves upward and is inserted into the corresponding sliding hole 8.

[0039] In this embodiment: Figure 1 Since the plane threaded ring 4 is located on the upper end surface of the detection plate 2, when the user works underground and applies torque to the drive shaft 6 upward, the plane threaded ring 4 may move up and separate from the detection plate 2. Since the elastic force of the pressure spring 13 is limited after all, and the elastic force is relatively not a stable force, it is necessary to Figure 1 As shown, a threaded sleeve 14 with a threaded outer surface is coaxially provided on the outside of the pressure-bearing spring 13, and the threaded sleeve 14 is coaxially fixed to the bottom end of the fixed cylinder 1, and can be manufactured integrally with the fixed cylinder 1. In addition, a locking screw sleeve 15 is required to be threadedly matched with the outer surface of the threaded sleeve 14, and a plane bearing 11 is coaxially fixedly provided at the bottom end of the locking screw sleeve 15, and the plane bearing 11 is in contact with the end face of the positioning shoulder 10. When in use, the locking screw sleeve 15 is mainly screwed to keep the plane bearing 11 in reliable contact with the positioning shoulder 10, and to withstand the axial pressure, so as to avoid the drive shaft 6 moving up during the installation process, which causes the plane threaded ring 4 and the detection plate 2 to separate. In addition, in order to facilitate the adjustment of the height position of the plane bearing 11, a hand wheel 12 can be coaxially fixed on the outside of the locking screw sleeve 15. By turning the hand wheel 12, the plane bearing 11 can be determined to be in contact with the positioning shoulder 10. When the detection plate 2 is extended into place, the locking screw sleeve 15 can be screwed upward, and the plane bearing 11 is separated from the positioning shoulder 10. When the locking screw sleeve 15 and the end face of the fixed tube 1 are in contact, it moves up to the limit. At this time, the drive shaft 6 is pushed upward, and the positioning shoulder 10 compresses the pressure spring 13 to the position in contact with the plane bearing 11. At this time, the detection plate 2 that has been inserted into the top plate, its sliding hole 8 is axially penetrated by the above-mentioned detection conductor 3 to reach the initial contact position.

[0040] In the above description of the present invention, it should be noted that the terms "one side", "the other side", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0041] In addition, the term "same" does not mean that the parts must be absolutely the same, but slight differences are allowed. The term "vertical" only means that the positional relationship between the parts is more vertical than "parallel", and does not mean that the structure must be completely vertical, but can be slightly tilted.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A coal mine roof settlement monitoring device, characterized in that: The invention comprises a fixed cylinder (1) for fixing in a drill hole, wherein a plurality of detection plates (2) are arranged in the fixed cylinder (1) at intervals along its axial direction, wherein each layer of detection plates (2) is slidably installed along the radial direction of the fixed cylinder (1), and all detection plates (2) of each layer are arranged in a ring array; when each detection plate (2) extends out of the fixed cylinder (1) to a set length, it is just sleeved on a rod-shaped detection conductor (3), and the detection conductor (3) is arranged parallel to the axial direction of the fixed cylinder (1), so that the detection plate (2) extending out of the fixed cylinder (1) and inserted into the top plate can slide vertically along the corresponding strip hole (9) opened on the side wall of the fixed cylinder (1) with the detection conductor (3) as a guide when the top plate sinks; The bottom end of the detection conductor (3) is connected to one end at a breakpoint in a detection circuit, and the detection board (2) is connected to the other end at the breakpoint. When the detection board (2) slides down to a corresponding position on the detection conductor (3), the portion between the detection board (2) and the bottom end of the detection conductor (3) is connected to the detection circuit. The detection circuit can measure the voltage or current of the connected detection conductor (3), and the voltage or current is used to characterize the amount of sinking of the top plate.

2. The coal mine roof settlement monitoring device according to claim 1, characterized in that: The detection plate (2) achieves axial sliding through a plurality of hydraulic rods or electric push rods radially installed in the fixed cylinder (1), and all the hydraulic rods or electric push rods move synchronously in telescopic manner.

3. The coal mine roof settlement monitoring device according to claim 1, characterized in that: The upper surface of the detection plate (2) has a planar thread, and the upper surface of each layer of the detection plate (2) is meshed with a corresponding planar thread ring (4), and the planar thread ring (4) is coaxially rotatably mounted in the fixed tube (1), and all the planar thread rings (4) are coaxially fixed on the same driving shaft (6) through their respective connecting rods (5), and the driving shaft (6) is coaxially rotatably mounted in the fixed tube (1), and its bottom end extends out of the fixed tube (1) and can be connected to an external driving element to achieve self-rotation; the top surface of the detection conductor (3) is used to support the lower surface of the detection plate (2) and slide with it.

4. The coal mine roof settlement monitoring device according to claim 3 is characterized in that: The driving shaft (6) is provided with a plurality of shaft journals (7). In a non-working state, one end of the detection plate (2) is in contact with the shaft journal (7), and the other end thereof is flush with the surface of the fixing cylinder (1).

5. The coal mine roof settlement monitoring device according to claim 3, characterized in that: The detection conductor (3) comprises an insulating core rod (301), on which a resistance wire (302) is spirally wound along its length direction, and two adjacent turns of the resistance wire (302) do not contact each other. The bottom end of the resistance wire (302) is connected to one end of the breakpoint, and the part where the resistance wire (302) contacts the sliding hole (8) on the detection plate (2) is used to connect to the other end of the breakpoint.

6. The coal mine roof settlement monitoring device according to claim 3, characterized in that: The bottom end of the sliding hole (8) is a trumpet-shaped structure, the top end of the detection conductor (3) has a rounded corner, and when the plane threaded ring (4) is rotated to the limit, the detection plate (2) just slides out to the position where the sliding hole (8) is directly opposite to the insulating core rod (301) below it.

7. The coal mine roof settlement monitoring device according to claim 6, characterized in that: The bottom end of the detection conductor (3) is vertically fixed to the upper end surface of the planar threaded ring (4) opposite thereto, and the drive shaft (6) can be axially moved upward by a displacement when the detection plate (2) slides out to a set length, so that the upper end of the detection conductor (3) can be axially slidably inserted into the corresponding sliding hole (8).

8. The coal mine roof settlement monitoring device according to claim 7, characterized in that: A positioning shoulder (10) is fixed on a section of the driving shaft (6) extending out of the bottom end of the fixing tube (1), and a pressure spring (13) is sleeved between the positioning shoulder (10) and the bottom end of the fixing tube (1). The pressure spring (13) always tends to push the positioning shoulder (10) downward, so that the plane threaded ring (4) and the detection plate (2) in a non-working state maintain a meshing transmission relationship. When the bottom end of the driving shaft (6) is pushed upward, all the plane threaded rings (4) are separated from the detection plate (2), and the detection conductor (3) moves upward and is inserted into the corresponding sliding hole (8).

9. The coal mine roof settlement monitoring device according to claim 8, characterized in that: A threaded sleeve (14) with a threaded outer surface is coaxially provided on the outside of the pressure-bearing spring (13). The threaded sleeve (14) is coaxially fixed to the bottom end of the fixed cylinder (1). A locking screw sleeve (15) is threadedly matched with the threaded outer surface of the threaded sleeve (14). A plane bearing (11) is coaxially provided at the bottom end of the locking screw sleeve (15). The plane bearing (11) is in contact with the end surface of the positioning shaft shoulder (10), and a hand wheel (12) is coaxially fixed to the outside of the locking screw sleeve (15).

10. The coal mine roof settlement monitoring device according to claim 1, characterized in that: The detection plate (2) has a fan-shaped plate structure, and its large end is used to be inserted into the top plate.

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