A freely expandable fiber Bragg grating strain sensor

Abstract

The present application relates to the technical field related to optical deformation measurement equipment, and discloses a freely expandable fiber Bragg grating strain sensor. In order to solve the problem that the sensor is not easy to place in the deep hole area, two freely movable detection gear row arms are arranged on the mounting frame. When the deep hole needs to be inspected, it is only necessary to fix the mounting frame, and then use the two detection gear row arms to extend into the hole and support it. Since the length of the detection gear row arms can be adjusted according to the use requirements, it is possible to detect in the deep hole. After the detection gear row arms are supported on the part to be tested in the hole, the strain detection plate is fixed between the limit seats reserved to the outside of the hole. When the part to be tested is deformed, the deformation is transmitted to the strain detection plate outside the hole by using the detection gear row arms. The fiber Bragg grating sensor in the strain detection plate reflects the strain size and outputs it to the control end, and finally achieves the effect of expansion in the hole of the detection fixture and detection outside the hole.

Description

Technical Field

[0001] The present application relates to the technical field related to optical deformation measurement equipment, and in particular to a freely expandable fiber grating strain sensor. Background Art

[0002] The working principle of fiber Bragg grating strain sensor is based on the Bragg diffraction effect of fiber Bragg grating. When the fiber Bragg grating is subjected to strain perpendicular to the measurement direction, the fiber grid spacing will change, thereby changing the Bragg reflection characteristics of the fiber Bragg grating. At this time, the strain information can be obtained by reading the reflected light signal of the fiber Bragg grating. Specifically, the strain directly affects the wavelength drift of the fiber Bragg grating. By measuring this wavelength drift, the magnitude of the strain can be calculated.

[0003] At present, there are two main types of fixing methods for fiber Bragg grating strain sensors: adhesive fixing and bolt fastening. These two traditional fixing methods can effectively meet the needs of sensor layout in most application scenarios, ensuring that the sensors can work stably and accurately collect data. However, when the application environment becomes complex and special, such as in scenarios where geological conditions are complex such as surrounding rocks and mines and deep hole detection becomes necessary, the limitations of these fixing methods gradually become apparent.

[0004] In deep hole detection of surrounding rocks or mines, the size of the aperture is usually limited due to concerns that an overly large aperture may damage the structural integrity of the detection site. Although this small aperture design protects the detection site, it poses a huge challenge to the fixation of the sensor. Adhesive fixation may weaken the bonding force due to factors such as hole wall roughness, humidity or chemical properties, and the sensor cannot be firmly fixed in the hole; bolt fastening is limited by the aperture size, making it difficult to find a suitable installation space, and the tightening process of the bolt may also cause additional damage to the hole wall.

[0005] What is even more difficult is that as the hole depth increases, it is difficult for construction workers to directly reach the bottom of the hole, which further increases the difficulty of fixing the sensor. Even if the sensor can be barely inserted into the hole, the measurement data may be distorted due to loose fixation or position offset, and it may not truly reflect the strain situation in the deep hole. Therefore, in this special environment, traditional gluing and bolting methods are often not competent, thus limiting the wide application and advantages of fiber Bragg grating strain sensors in related fields. Summary of the invention

[0006] The present application proposes a freely expandable fiber Bragg grating strain sensor, which has the advantages of detecting expansion inside the fixture hole and detection outside the hole, and is used to solve the problem of difficulty in placing sensors in deep hole areas mentioned in the above background technology.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme: a freely expandable fiber grating strain sensor, comprising: a mounting frame, the two ends of the upper slide plate are movable on the inner side of the mounting frame using the upper sliding block, the two ends of the lower slide plate are movable on the inner side of the mounting frame using the lower sliding block, and the bottom of the upper slide plate and the surface of the lower slide plate are both movably mounted with detection tooth row arms; a fastening top rod, which is threadedly connected to the end of the detection tooth row arm; a strain detection plate, the bottom of which is fixed to the lower sliding block and the side is installed in the upper sliding block, a fiber grating sensor is arranged inside the strain detection plate, and optical fiber data lines are respectively connected to the two ends of the fiber grating sensor.

[0008] Furthermore, a synchronization rod is movably inserted between the detection gear row arms, and a plurality of cylindrical holes having a diameter equal to that of the synchronization rod are formed on the surface of the detection gear row arms.

[0009] Furthermore, it also includes: an adjusting box, which is fixed on the surface of the upper slide plate and has an adjusting cone seat installed inside; a one-way rack, which is arranged on the outer side of the adjusting cone seat; an adjusting bolt, which is sleeved on the top of the adjusting box, and the side of the adjusting bolt and the adjusting cone seat are threadedly connected, and an adjusting handle is fixed on the top; a guide tube, which is fixed to the middle part of the outer side of the adjusting box and has a locking push rod installed inside, and a locking spring located on the inner side of the guide tube is fixed to one end of the locking push rod; a punch push rod, which is fixed on the end face of the locking push rod; a limit seat, which is fixed to the end of the guide tube, and the strain detection plate passes between the limit seat and the end of the guide tube, and a limit hole is opened on the surface of the limit seat.

[0010] Furthermore, there are multiple one-way racks, and the cross-section of the one-way racks is a right triangle.

[0011] Furthermore, it also includes: a central slide, movably installed at the bottom of the upper slide, and two transmission rods are hinged on the top of which; a push rod slide is hinged at the end of one transmission rod, and a guide slider is movably installed at the end of the other transmission rod, and the push rod slide and the guide slider can both move in the horizontal direction of the upper slide; a limiting push rod is fixed on the surface of the push rod slide; a locking hole is provided at the bottom of the adjusting cone seat; a locking tooth head is fixed on the bottom of the guide slider; a driving rod is fixed on the top of the guide slider, and the driving rod is fixedly connected to the end of the locking spring.

[0012] Furthermore, there are multiple locking holes, and the multiple locking holes are distributed in a ring shape.

[0013] Furthermore, a pressure plate slider is movably installed on the side of the mounting frame, and the end of the pressure plate slider is fixedly connected to a fastening pressure plate located below the central slide seat, and the fastening pressure plate and the adjusting bolt are movably installed.

[0014] Furthermore, a warning gear is movably installed on the top of the driving rod, a warning tooth row meshing with the warning gear is fixedly installed on the outer side of the guide tube, a warning rod is fixedly connected to the side of the warning gear, and a metal bell is fixedly connected to the side of the guide tube.

[0015] The present invention has the following beneficial effects:

[0016] The present application provides a freely expandable fiber Bragg grating strain sensor, which integrates two independently adjustable and freely movable detection tooth row arms on a mounting frame. These detection tooth row arms are not only sturdy in structure, but also have a length that can be flexibly adjusted according to actual detection needs, ensuring that their ends can penetrate and adapt to holes of various depths / shapes.

[0017] When performing deep hole inspection, the mounting frame is first firmly fixed to the outside of the hole, and then the two detection tooth row arms are slowly extended into the hole through manual adjustment until they can be firmly supported on the key parts to be tested in the hole. This design cleverly solves the problem that traditional sensors are difficult to reach the inside of deep holes, and significantly improves the comprehensiveness and accuracy of inspection.

[0018] Once the detection teeth are correctly positioned in the hole, they become a bridge connecting the strain inside the hole with the detection equipment outside the hole. At this time, the strain detection plate is accurately installed between the limit seats reserved outside the hole to ensure a stable mechanical transmission path between it and the detection teeth. When the part to be tested in the hole is deformed due to external factors (such as pressure, temperature, etc.), this deformation will be immediately transmitted to the strain detection plate outside the hole through the detection teeth.

[0019] The strain detection board has a built-in high-precision fiber Bragg grating sensor, which has extremely high sensitivity and anti-interference ability. It can capture the changes in the grating wavelength caused by deformation in real time and accurately, and then convert these changes into electrical signals or digital signals, which are directly output to the control end or data processing system through the signal transmission line. The control end can quickly calculate the specific value of the strain in the hole by analyzing these signals, and display it to the user in an intuitive way, realizing the automation and intelligence of the whole process from expansion inside the hole to precise detection outside the hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute a part of the specification, illustrate embodiments disclosed in the present application and, together with the description, serve to explain the principles disclosed in the present application.

[0021] The present application can be more clearly understood from the following detailed description with reference to the accompanying drawings, in which:

[0022] Figure 1 It is a schematic diagram of the overall three-dimensional structure;

[0023] Figure 2It is a schematic diagram of the overall three-dimensional structure of the back;

[0024] Figure 3 It is a schematic diagram of the overall front plan section structure;

[0025] Figure 4 It is a schematic diagram of the positions and structures of the components between the upper and lower slides;

[0026] Figure 5 It is a schematic diagram of the internal three-dimensional structure of the regulating box;

[0027] Figure 6 This is a schematic diagram of the internal three-dimensional structure of the guide tube;

[0028] Figure 7 It is a schematic diagram of the three-dimensional structure of the adjusting cone seat;

[0029] Figure 8 Schematic diagram of the position of the fiber grating sensor when it is working.

[0030] In the figure: 1, mounting frame; 2, upper slide plate; 200, upper sliding block; 3, lower slide plate; 300, lower sliding block; 4, detection gear row arm; 400, synchronization rod; 401, fastening top rod; 5, fastening pressure plate; 500, pressure plate slider; 6, adjustment handle; 7, adjustment box; 8, adjustment bolt; 9, guide tube; 10, warning gear row; 11, warning gear; 12, warning rod; 13, metal bell; 14, limit seat; 14 0. Limit hole; 15. Strain detection plate; 16. Fiber Bragg grating sensor; 160. Fiber optic data line; 17. Drive rod; 18. Guide slider; 180. Locking tooth head; 19. Locking push rod; 190. Locking spring; 191. Punch plate push rod; 20. Adjusting cone seat; 201. One-way rack; 202. Locking hole; 21. Limit push rod; 210. Push rod slide; 22. Center slide; 220. Transmission pull rod. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0032] Embodiment 1

[0033] See also Figure 1 It can be seen that both sides of the mounting frame 1 are provided with "L"-shaped connectors fixedly connected by bolts. When fixing is required, the mounting frame 1 can be fixed as a whole to the outside of the hole to be measured by passing fasteners such as bolts through corresponding holes.

[0034] The upper sliding blocks 200 fixed by bolts at both ends of the upper slide plate 2 move on the inner side of the mounting frame 1. Similarly, the lower sliding blocks 300 fixed by bolts at both ends of the lower slide plate 3 move on the inner side of the mounting frame 1, and the lower slide plate 3 is located below the upper slide plate 2. Figure 1 and Figure 2 It can be clearly seen that the detection gear row arm 4 is movably mounted on the bottom of the upper slide 2 and the surface of the lower slide 3. Moreover, the detection gear row arm 4 and the upper slide 2 / lower slide 3 are connected by a dovetail groove, so that the detection gear row arm 4 can only reciprocate along a fixed direction. When the detection gear row arm 4 is inserted into the hole to be tested, since both the upper slide 2 and the lower slide 3 can move up and down along the inner side of the mounting frame 1, the spacing between the two detection gear row arms 4 can be changed by adjusting the spacing between the upper slide 2 and the lower slide 3, thereby adapting to the detection of holes of different sizes; at the same time, since the detection gear row arm 4 is limited by the dovetail groove to move only along the upper slide 2 / lower slide 3, the detection gear row arm 4 can be inserted into holes of different depths, and finally the detection gear row arm 4 can be fixed in detection holes of different depths / diameters. From Figure 2 As can be seen in the figure, the end of the detection gear row arm 4 is threadedly connected with a fastening push rod 401, so that the end of the detection gear row arm 4 is more easily limited to the required position inside the detection hole.

[0035] In order to facilitate the real-time transmission of information inside the hole to the outside, combined with Figure 8 It can be seen that the side of the lower sliding block 300 is provided with a strain detection plate 15 fastened by bolts, and the side of the strain detection plate 15 is installed in the upper sliding block 200. Since the middle of the strain detection plate 15 is provided with a fiber optic Bragg grating sensor 16 bonded by glue, both ends of the fiber optic Bragg grating sensor 16 are respectively connected with a fiber optic data line 160 for outputting the detection data to the outside. Therefore, when the upper sliding block 200 and the lower sliding block 300 move relative to each other, the displacement between the two will cause the strain detection plate 15 to drive the fiber optic Bragg grating sensor 16 inside it to deform, and the fiber optic Bragg grating sensor 16 uses electrical signals or data signals to output to the control end or the data processing system via the fiber optic data line 160, so that the operator can know the changes in the detection part here.

[0036] In actual application of the first embodiment, the mounting frame 1 is fixed to the outside of the hole to be tested by fasteners, and the detection gear row arm 4 is inserted into the hole to be tested. The upper slide plate 2 and the lower slide plate 3 move up and down along the mounting frame 1, so that the detection gear row arm 4 can adapt to different hole diameters; the detection gear row arm 4 is moved along the upper slide plate 2 / lower slide plate 3, so that the detection gear row arm 4 can adapt to detection at different depths. After the fastening push rod 401 at the top of the detection gear row arm 4 is pushed to the part to be tested in the hole, it is fastened to the upper sliding block 200 through the strain detection plate 15. Combined with the fact that the bottom of the strain detection plate 15 has been fastened to the lower sliding block 300 before installation, the strain detection plate 15 can accurately reflect whether displacement occurs between the upper sliding block 200 and the lower sliding block 300, that is, whether changes occur between the two detection gear row arms 4 due to deformation of the detection part.

[0037] When the detection part changes, the two detection tooth row arms 4 are forced to squeeze each other, and the strain detection plate 15 is squeezed synchronously. The fiber grating sensor 16 inside the strain detection plate 15 outputs the grating wavelength change caused by the deformation to an external control unit via the optical fiber data line 160, so that the operator can know the real-time data of the detection part here.

[0038] As a supplement to Example 1, Figure 1 and Figure 2 It can be seen that a synchronization rod 400 is movably inserted between the detection gear row arms 4, and a plurality of cylindrical holes are provided on the surface of the detection gear row arms 4 on the lower slide plate 3, and the diameter of the cylindrical holes is the same as that of the synchronization rod 400. Therefore, the synchronization rod 400 can not only make the detection gear row arms 4 extend synchronously, so that the center lines between the two fastening top rods 401 are on the same straight line, and accurate detection of the hole can be achieved; the different lengths of the detection gear row arms 4 extending into the hole can also be used to change the parts detected by the two fastening top rods 401, so as to better reflect the changes in various parts in the hole. This method can be selected by the operator, making the detection of the detection gear row arms 4 flexible.

[0039] Embodiment 2

[0040] Further improvements are made based on Example 1. Figure 2 , Figure 3 and Figure 5 It can be clearly seen that the surface of the upper slide plate 2 is fixedly connected to the inner hollow adjustment box 7, and the adjustment box 7 is internally provided with an adjustment cone seat 20 that can move up and down along its central axis. Figure 7As shown, the shape of the adjusting cone seat 20 is a combination of a top truncated cone and a bottom cylindrical shape, wherein a plurality of one-way racks 201 distributed at equal angles are connected to the cylindrical outer side of the adjusting cone seat 20, and the cross-sectional shape of the one-way rack 201 is a right triangle. When the locking push rod 19 pushes against the one-way rack 201, the adjusting cone seat 20 is limited to one-way rotation. The top movable sleeve of the adjusting box 7 is provided with an adjusting bolt 8, and the adjusting bolt 8 and the adjusting cone seat 20 are threadedly connected. The top of the adjusting bolt 8 is fixedly connected with an adjusting handle 6. The adjusting handle 6 is manually turned to enable the adjusting bolt 8 to rotate synchronously. The bottom end of the adjusting bolt 8 is arranged with a ball. When the bottom of the adjusting bolt 8 reaches the upper surface of the lower slide 3, the ball can be used to reduce the friction resistance between the lower slide 3 and the adjusting bolt 8.

[0041] For the arrangement of the locking push rod 19, refer to Figure 2 It can be clearly seen that the middle part of the outer side of the adjustment box 7 is fixedly connected with the guide tube 9, and the guide tube 9 is internally provided with a locking push rod 19 extending into the adjustment box 7, and one end of the locking push rod 19 is fixed with a locking spring 190 located inside the guide tube 9, and the elastic force of the locking spring 190 is used to make the end of the locking push rod 19 always press against the side of the adjustment cone seat 20. Figure 4 , Figure 6 and Figure 8 It can be clearly seen that the end face of the locking push rod 19 is symmetrically arranged with a punching plate push rod 191 located inside the guide tube 9. Correspondingly, the end of the guide tube 9 is fixedly connected with a limit seat 14 relatively far away from the adjustment box 7, and the strain detection plate 15 passes between the limit seat 14 and the end of the guide tube 9. The surface of the limit seat 14 is provided with a limit hole 140 corresponding to the punching plate push rod 191. When the punching plate push rod 191 passes through the strain detection plate 15 and enters the limit seat 14, the punching plate push rod 191 is relative to the punching head, and the limit hole 140 is equivalent to the punching die. Therefore, the punching plate push rod 191 is used to punch the strain detection plate 15. After the punching plate push rod 191 passes through the strain detection plate 15, the punched circular hole is used to limit the position of the strain detection plate 15 by the punched out punching plate push rod 191.

[0042] In actual application, a fiber optic Bragg grating sensor 16 of appropriate length is selected for pre-installation. Specifically, the bottom of the strain detection plate 15 is fastened to the lower sliding block 300 by bolts, and the side of the strain detection plate 15 is slidingly connected to the upper sliding block 200 and the limit seat 14 respectively. Therefore, the lower sliding block 300 can be used to push the strain detection plate 15 to move relatively along the upper sliding block 200 and the limit seat 14.

[0043] Under normal conditions, the locking push rod 19 is subjected to the elastic force of the locking spring 190 so that its top is pressed against the outer inclined surface of the adjusting cone seat 20. At this time, the punching plate push rod 191 is relatively far away from the strain detection plate 15. After the detection gear row arm 4 is manually adjusted to make the fastening push rod 401 push against the desired detection position in the hole, the adjusting handle 6 is rotated forward to make the adjusting bolt 8 move downward along the adjusting cone seat 20. As the adjusting bolt 8 moves downward, it will eventually push against the surface of the lower slide plate 3. When the adjusting bolt 8 pushes against the surface of the lower slide plate 3, its downward movement will be blocked. With the continued twisting of the adjusting handle 6, the upper slide plate 2 and the lower slide plate 3 have a tendency to move away from each other, causing the fastening push rods 401 on the upper slide plate 2 and the lower slide plate 3 to be pressed against the measured position in the hole.

[0044] The adjusting handle 6 is continuously turned, so that the upward strength of the adjusting cone seat 20 along the adjusting bolt 8 can overcome the elastic force of the locking spring 190. As the adjusting cone seat 20 moves upward along the adjusting bolt 8, it pushes the locking push rod 19 to move to the left. The direction is referenced Figure 3 The left locking push rod 19 will push the punch push rod 191 to squeeze the strain detection plate 15, and finally leave a cylindrical hole on the surface of the strain detection plate 15. The punch push rod 191 passes through the cylindrical hole and enters the limit hole 140. The continuously upward adjustment cone seat 20 will make the locking push rod 19 push to the one-way rack 201, thus completing the limitation of the position of the strain detection plate 15.

[0045] Finally, by rotating the adjustment handle 6 in the reverse direction, the adjustment bolt 8 moves upward along the adjustment cone seat 20. At the same time, because the locking push rod 19 is pressed against the one-way rack 201, when the adjustment handle 6 rotates in the reverse direction and drives the adjustment cone seat 20 to rotate, the one-way movement between the locking push rod 19 and the one-way rack 201 is limited, forcing the adjustment cone seat 20 not to rotate in the reverse direction with the adjustment handle 6. After the adjustment bolt 8 rotates in the reverse direction along the adjustment cone seat 20, its bottom will be away from the lower slide plate 3. When the detection part has a relative displacement, the relative movement between the upper slide plate 2 and the lower slide plate 3 will not be disturbed by the adjustment bolt 8, thereby ensuring the stable detection work.

[0046] The second embodiment of the present invention essentially provides a method for fixing the fastening pressure plate 5. This method only requires that after the mounting frame 1 is fixed, the operator manually rotates the adjustment handle 6 to make the fastening top rod 401 tightly press against the desired detection position, and then the strain detection plate 15 can be fixed, thereby limiting its working order and ensuring that the fixation of the strain detection plate 15 is based on the stable placement of the detection tooth row arm 4. This method can greatly improve the flexibility and accuracy during construction, especially when working at high altitudes. When using this equipment, there is no need to carry out other fastening work, and it is easier to arrange the fiber optic grating sensor 16 at high altitudes.

[0047] Embodiment 3

[0048] Further improvements are made based on Example 2. Figure 3 and Figure 5 It can be clearly seen that a central slide 22 is movably mounted at the bottom of the upper slide 2, and the central slide 22 can reciprocate up and down along the bottom of the upper slide 2, and two transmission rods 220 are hinged at the top of the central slide 22, a top rod slide 210 is hinged at the end of one transmission rod 220, and a guide slider 18 is movably mounted at the end of the other transmission rod 220, and both the top rod slide 210 and the guide slider 18 can move in the horizontal direction of the upper slide 2. Specifically, when the central slide 22 moves upward, the transmission rod 220 will push the top rod slide 210 and the guide slider 18 away from each other; similarly, when the central slide 22 moves downward, the transmission rod 220 pulls the guide slider 18 and the top rod slide 210 closer to each other.

[0049] The surface of the push rod slide 210 is fixedly mounted with a limit push rod 21 located inside the adjustment box 7. Figure 7 It can be seen that the bottom of the adjusting cone seat 20 is provided with a locking hole 202 corresponding to the limiting push rod 21. There are multiple locking holes 202, and the multiple locking holes 202 are distributed in a ring shape. Since the adjacent locking holes 202 are relatively close to each other, the limiting push rod 21 can be selectively inserted into the locking hole 202. In order to facilitate insertion, the top of the limiting push rod 21 and the opening of the locking hole 202 are both provided with an oblique angle. Combined with the above, since the limiting push rod 21 can only move horizontally along the surface of the upper slide plate 2, when the limiting push rod 21 is inserted into the locking hole 202, the limiting push rod 21 can be used to limit the rotation of the adjusting cone seat 20.

[0050] The bottom of the guide slider 18 is fixedly installed with a locking tooth head 180 located on one side of the detection gear row arm 4. Since the guide slider 18 can move horizontally along the surface of the upper slide 2, when the locking tooth head 180 is close to the detection gear row arm 4, the engagement between the two is used to restrict the detection gear row arm 4 from moving, thereby restricting the relative movement between the detection gear row arm 4 and the upper slide 2 / lower slide 3. The top of the guide slider 18 is fixedly installed with a driving rod 17 extending into the guide tube 9. Figure 6 It can be clearly seen that the drive rod 17 is fixedly connected to the end of the locking spring 190, one end of the locking spring 190 is fixed to the locking top rod 19, and the other end is fixed to the drive rod 17. Under the action of its own elastic force, the drive rod 17 is forced to always have a tendency to move away from the locking top rod 19.

[0051] When applying it in specific Figure 3As shown, under normal conditions, the limit push rod 21 is inserted into the locking hole 202, and is pulled by the transmission pull rod 220 and the center slide 22 so that the guide slider 18 drives the locking tooth head 180 to be relatively away from the detection gear row arm 4. At the same time, the locking spring 190 is squeezed between the driving rod 17 and the locking push rod 19, and the locking push rod 19 is forced to always press against the inclined surface of the adjusting cone seat 20 by the elastic force of the locking spring 190.

[0052] After the mounting frame 1 is fixed to the outside of the hole to be tested and the detection gear row arm 4 is inserted into the hole to a suitable depth, the adjusting handle 6 is turned forward to make the adjusting bolt 8 move downward along the adjusting cone seat 20. Finally, the lower slide plate 3 is pressed by the bottom of the adjusting bolt 8 so that the detection gear row arm 4 on the upper slide plate 2 and the lower slide plate 3 is pressed into the hole to be tested. As the adjusting handle 6 is turned forward, the adjusting cone seat 20 is guided and moves upward by the limiting push rod 21. As the adjusting cone seat 20 is pushed upward on the inclined surface, the locking push rod 19 further presses the locking spring 190, and the locking push rod 19 pushes the punching plate push rod 191 to punch the strain detection plate 15. Finally, the locking push rod 19 reaches the one-way rack 201. As the adjusting cone seat 20 continues to move upward, the locking hole 202 will disengage from the limiting push rod 21. After that, the elastic force of the locking spring 190 will force the locking push rod 19 to drive the guide slider 18 to the left, and finally the locking tooth head 180 will abut against the detection gear row arm 4, thereby restricting the detection gear row arm 4 from moving along the upper slide plate 2.

[0053] In combination with the contents described in Example 2, since the two detection gear row arms 4 are connected together by a synchronization rod 400, when the detection gear row arm 4 below the upper slide plate 2 cannot move, the detection gear row arm 4 on the lower slide plate 3 cannot move either. This method can ensure that after the detection gear row arm 4 is fastened inside the hole to be tested, the detection gear row arm 4 is locked by the locking tooth head 180, thereby preventing the detection gear row arm 4 from moving along the upper slide plate 2 / lower slide plate 3 and causing the detection part to shift, and ultimately limiting the detection gear row arm 4 during the detection process, and can only rely on the upper sliding block 200 / lower sliding block 300 on the upper slide plate 2 / lower slide plate 3 to move up and down along the mounting frame 1, thereby ensuring that the movement changes between the detection gear row arms 4 can cause the strain detection plate 15 to drive the fiber grating sensor 16 to deform.

[0054] On this basis, combined with Figure 2 and Figure 3It can be clearly seen that a pressure plate slider 500 located between the upper sliding block 200 and the lower sliding block 300 is movably installed on the side of the mounting frame 1, and the pressure plate slider 500 can reciprocate up and down along the mounting frame 1, and the end of the pressure plate slider 500 is fixedly connected to a fastening pressure plate 5 located below the center slide seat 22, and is movably installed between the fastening pressure plate 5 and the adjusting bolt 8. The connection position between the fastening pressure plate 5 and the adjusting bolt 8 is relatively fixed, but the adjusting bolt 8 can rotate in the fastening pressure plate 5. In specific implementation, when the adjusting bolt 8 rotates forward, the adjusting bolt 8 moves downward through the adjusting cone seat 20, and the bottom of the adjusting bolt 8 pushes the fastening pressure plate 5 to drive the pressure plate slider 500 to move synchronously downward along the mounting frame 1.

[0055] When the punch plate push rod 191 locks the strain detection plate 15, it means that the locking hole 202 has been separated from the limit push rod 21. Figure 3 It can be seen that when the cone seat 20 is adjusted to move upward and the locking hole 202 is separated from the limit push rod 21, the guide slider 18 is pushed to the left by the elastic force of the punch plate push rod 191. At the same time, the guide slider 18 will pull the center slide 22 upward through the transmission pull rod 220 during the movement to the left. After the center slide 22 moves upward, it will push the push rod slide 210 to move to the right according to the transmission pull rod 220, so that the limit push rod 21 is relatively away from the locking hole 202, and the limit push rod 21 moves to the inner side of the annular locking hole 202.

[0056] Afterwards, by twisting the adjustment handle 6 in the reverse direction, the adjustment cone seat 20 cannot rotate in the reverse direction due to the restriction of the locking push rod 19 against the one-way rack 201, so that the adjustment bolt 8 pulls the fastening plate 5 to move upward. When the fastening plate 5 presses against the center slide 22, it will further push the center slide 22 to move upward, and the upward movement trend of the center slide 22 increases. On the one hand, the strength of the driving pull rod 220 to push the guide slider 18 to move to the left increases, so that the contact strength between the locking tooth head 180 and the detection gear row arm 4 increases, and the movement of the detection gear row arm 4 is further restricted; on the other hand, the driving pull rod 220 is used to push the push rod slide 210 to the right, so that the limit push rod 21 is further away from the locking hole 202. As the adjustment bolt 8 is continuously tightened, the fastening plate 5 is blocked by the center slide 22 and cannot move. When the adjustment cone seat 20 is pressed downward, it will be pressed tightly to the top of the limit push rod 21. The limit of the limit push rod 21 prevents the adjustment cone seat 20 from moving downward.

[0057] It can be seen that when the adjusting handle 6 drives the adjusting bolt 8 to be continuously turned in the opposite direction, the outer side of the adjusting cone seat 20 will always be at the one-way rack 201, which can prevent the locking push rod 19 from further extending into the adjusting box 7 under the elastic force of the locking spring 190. This method can ensure that the punch push rod 191 is always connected to the strain detection plate 15, thereby ensuring the stability of the connection; at the same time, through the pressure on the center slide 22, the connection strength between the locking tooth head 180 and the detection tooth row arm 4 is forced to increase, further limiting the detection tooth row arm 4 from being able to move freely during the detection process, thereby further ensuring the accuracy / stability of the detection.

[0058] Embodiment 4

[0059] Further improvements based on Example 3 are provided. Figure 4-Figure 6 As can be seen in the figure, the top of the driving rod 17 is movably mounted with a warning gear 11 that moves with it. Correspondingly, the outer side of the guide tube 9 is fixedly mounted with a warning tooth row 10 that meshes with the warning gear 11. When the driving rod 17 moves along the center line of the guide tube 9, the meshing of the warning gear 11 on the warning tooth row 10 forces it to rotate. The side of the warning gear 11 is fixedly connected with a warning rod 12. At the same time, the side of the guide tube 9 is fixedly connected with a metal bell 13. There are two metal bells 13, which are respectively located near the ends of the warning tooth row 10.

[0060] Under normal conditions, the limit push rod 21 is inserted into the locking hole 202. As described in the third embodiment, the driving rod 17 is pressed against the locking spring 190 through the central slide 22 and the guide slider 18. At this time, the warning rod 12 is against the metal bell 13 on the right.

[0061] As the adjustment handle 6 is continuously turned in the forward direction, when the limit push rod 21 disengages from the locking hole 202, it indicates that the strain detection plate 15 has been fixed. At the same time, the locking spring 190 will push the drive rod 17 to move to the left. When the drive rod 17 drives the warning gear 11 to move to the left, the warning gear 11 deflects counterclockwise through the engagement with the warning tooth row 10, so that the warning rod 12 hits the metal bell 13 on the left, and the metal bell 13 on the left makes a sound, thereby alerting the user that the strain detection plate 15 has been fixed.

[0062] If at this time, the strain detection plate 15 needs to be removed for adjustment, the adjustment handle 6 is turned forward so that the adjustment bolt 8 no longer applies pressure to the center slide 22, and the warning rod 12 is manually pulled so that the warning rod 12 is pressed tightly against the metal bell 13 on the right. At this time, the warning gear 11 will pull the driving rod 17 to move to the right, thereby moving the guide slider 18 away from the detection gear row arm 4. At the same time, the guide slider 18 pushes the center slide 22 downward through the transmission pull rod 220, so that the transmission pull rod 220 pulls the top rod slide 210 to move to the left, forcing the limit top rod 21 to move to the bottom of the locking hole 202. On this basis, the adjustment handle 6 is continuously turned in the opposite direction so that the adjustment handle 6 is pressed on the center slide 22 and cannot continue to move upward. Since the limiting push rod 21 is located below the locking hole 202 at this time, when the adjusting bolt 8 rotates to force the adjusting cone seat 20 to move downward, the locking hole 202 will be inserted into the limiting push rod 21. As the adjusting handle 6 is continuously turned in the opposite direction, the locking push rod 19 will again push onto the inclined surface of the adjusting cone seat 20. The locking push rod 19 is forced by the elastic force of the locking spring 190 to drive the punching plate push rod 191 away from the strain detection plate 15, thus releasing the position restriction of the punching plate push rod 191 on the strain detection plate 15, thereby facilitating the position adjustment of the strain detection plate 15.

[0063] This fourth embodiment can ensure that after the detection gear row arm 4 is tightened, the warning rod 12 is used to knock the metal bell 13 to warn the operator that it has been installed in place. When the installed detection gear row arm 4 needs to be adjusted in position, the detection position can be flexibly adjusted by pulling the warning rod 12 and cooperating with the rotation of the adjustment handle 6.

Claims

1. A freely expandable fiber Bragg grating strain sensor, characterized in that: include: The mounting frame (1) comprises an upper slide plate (2) and an upper slide block (200) at both ends of which are movable inside the mounting frame (1). The lower slide plate (3) and the lower slide block (300) are movable inside the mounting frame (1). The bottom of the upper slide plate (2) and the surface of the lower slide plate (3) are both movably mounted with a detection tooth row arm (4). The mounting frame (1) is fixed to the outside of the hole to be tested by fasteners. The detection tooth row arm (4) is inserted into the hole to be tested. The upper slide plate (2) and the lower slide plate (3) move up and down along the mounting frame (1), so that the detection tooth row arm (4) can adapt to different hole diameters. The detection tooth row arm (4) is moved along the upper slide plate (2) and the lower slide plate (3), so that the detection tooth row arm (4) can adapt to detection of different depths. A fastening push rod (401) is threadedly connected to the end of the detection gear row arm (4), and the fastening push rod (401) is pushed to the position to be tested in the hole to be tested; A strain detection plate (15) having a bottom fixed to a lower sliding block (300) and a side mounted in an upper sliding block (200); a fiber optic Bragg grating sensor (16) is arranged inside the strain detection plate (15); and both ends of the fiber optic Bragg grating sensor (16) are respectively connected to optical fiber data lines (160); The regulating box (7) is fixed on the surface of the upper slide plate (2), and an regulating cone seat (20) is mounted inside the regulating cone seat (20), wherein the regulating cone seat (20) is a combination of a top truncated cone and a bottom cylindrical shape; A one-way rack (201) is arranged on the cylindrical outer side of the adjusting cone seat (20), there are a plurality of one-way racks (201), and the cross-section of the one-way rack (201) is in the shape of a right triangle; An adjusting bolt (8) is sleeved on the top of the adjusting box (7), a side of the adjusting bolt (8) and an adjusting cone seat (20) are threadedly connected, and an adjusting handle (6) is fixed on the top; The guide tube (9) is fixed to the middle part of the outer side of the regulating box (7), and a locking push rod (19) is mounted inside the guide tube (9). A locking spring (190) located inside the guide tube (9) is fixed to one end of the locking push rod (19); A punch plate push rod (191) is fixed on the end surface of the locking push rod (19); A limit seat (14) is fixed to the end of the guide tube (9), and the strain detection plate (15) passes between the limit seat (14) and the end of the guide tube (9). A limit hole (140) is provided on the surface of the limit seat (14); Under normal conditions, the locking push rod (19) is subjected to the elastic force of the locking spring (190) so that its top is pressed against the outer inclined surface of the adjusting cone seat (20), and at this time, the punch plate push rod (191) is relatively far away from the strain detection plate (15); when the detection tooth row arm (4) is manually adjusted to make the fastening push rod (401) press against the position to be tested in the hole to be tested, the adjusting handle (6) is rotated forward to make the adjusting bolt (8) move downward along the adjusting cone seat (20), and as the adjusting bolt (8) moves downward, it will eventually press against the surface of the lower slide plate (3), and when the adjusting bolt (8) presses against the surface of the lower slide plate (3), its downward movement will be blocked, and as the adjusting handle (6) continues to be turned, the upper slide plate (2) and the lower slide plate (3) have a tendency to move away from each other, so that the fastening push rods (401) on the upper slide plate (2) and the lower slide plate (3) are pressed against the position to be tested in the hole to be tested; The adjusting handle (6) is continuously turned, so that the upward strength of the adjusting cone seat (20) along the adjusting bolt (8) can overcome the elastic force of the locking spring (190). As the adjusting cone seat (20) moves upward along the adjusting bolt (8), the locking push rod (19) is pushed to the left. The left-moving locking push rod (19) pushes the punch plate push rod (191) to squeeze the strain detection plate (15), leaving a cylindrical hole on the surface of the strain detection plate (15). The punch plate push rod (191) passes through the cylindrical hole and enters the limiting hole (140). The continuously upward adjusting cone seat (20) causes the locking push rod (19) to push to the one-way rack (201), thereby completing the limitation of the position of the strain detection plate (15); Finally, by rotating the adjusting handle (6) in the reverse direction, the adjusting bolt (8) moves upward along the adjusting cone seat (20). Since the locking push rod (19) is pressed against the one-way rack (201), when the adjusting handle (6) rotates in the reverse direction and drives the adjusting cone seat (20) to rotate, the one-way movement between the locking push rod (19) and the one-way rack (201) is restricted, forcing the adjusting cone seat (20) not to rotate in the reverse direction with the adjusting handle (6). After the adjusting bolt (8) rotates in the reverse direction along the adjusting cone seat (20), its bottom is away from the lower slide plate (3). When the part to be tested has a relative displacement, the relative movement between the upper slide plate (2) and the lower slide plate (3) will not be disturbed by the adjusting bolt (8), thereby ensuring the stable progress of the detection work.

2. The freely expandable fiber Bragg grating strain sensor according to claim 1, characterized in that: A synchronization rod (400) is movably inserted between the detection gear row arms (4), and a plurality of cylindrical holes having a diameter equal to that of the synchronization rod (400) are provided on the surface of the detection gear row arms (4).

3. The freely expandable fiber Bragg grating strain sensor according to claim 1, characterized in that: Also included are: A central slide (22) is movably mounted on the bottom of the upper slide (2), and two transmission pull rods (220) are hinged on the top of the central slide; A push rod slide seat (210) is hingedly connected to the end of one transmission rod (220), and a guide slide block (18) is movably mounted on the end of the other transmission rod (220), and both the push rod slide seat (210) and the guide slide block (18) can move in the horizontal direction of the upper slide plate (2); A limiting ejector rod (21) is fixed on the surface of the ejector rod sliding seat (210); A locking hole (202) corresponding to the limiting push rod (21) is formed at the bottom of the adjusting cone seat (20); A locking tooth head (180) is fixed to the bottom of the guide slide block (18). When the locking tooth head (180) is close to the detection tooth row arm (4), the detection tooth row arm (4) is restricted from moving by meshing therebetween, thereby restricting the relative movement between the detection tooth row arm (4) and the upper slide block (2) and between the detection tooth row arm (4) and the lower slide block (3); The driving rod (17) is fixed on the top of the guide slider (18), and the driving rod (17) is fixedly connected to the end of the locking spring (190).

4. The freely expandable fiber Bragg grating strain sensor according to claim 3, characterized in that: There are multiple locking holes (202), and the multiple locking holes (202) are distributed in a ring shape.

5. The freely expandable fiber Bragg grating strain sensor according to claim 3, characterized in that: A pressure plate slider (500) is movably mounted on the side of the mounting frame (1). The pressure plate slider (500) can reciprocate up and down along the mounting frame (1). The end of the pressure plate slider (500) is fixedly connected to a fastening pressure plate (5) located below the central slide seat (22). The fastening pressure plate (5) and the adjusting bolt (8) are movably mounted. The connection position between the fastening pressure plate (5) and the adjusting bolt (8) is relatively fixed, and the adjusting bolt (8) rotates in the fastening pressure plate (5).

6. The freely expandable fiber Bragg grating strain sensor according to claim 5, characterized in that: A warning gear (11) is movably mounted on the top of the driving rod (17) and moves with it; a warning tooth row (10) meshing with the warning gear (11) is fixedly mounted on the outer side of the guide tube (9); a warning rod (12) is fixedly connected to the side of the warning gear (11); and a metal bell (13) is fixedly connected to the side of the guide tube (9).

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