Centralized drainage device for fully mechanized coal mining face

Abstract

The invention belongs to the field of drainage devices, and provides a fully mechanized coal mining face centralized drainage device which comprises a drainage middle box, the drainage middle box comprises a box body, the two sides of the box body are communicated with a water inlet pipe and a drainage pipe respectively, and a middle partition plate is arranged in the middle of the box body and divides the box body into a primary filtering cavity and a secondary filtering cavity; a primary filtering piece is arranged in the primary filtering cavity and comprises a filtering box arranged in the box body, a water inlet is formed in one side face of the filtering box, and the water inlet is communicated with a water inlet pipe; by arranging the primary filtering cavity, the secondary filtering cavity and the filtering box, during use, sewage is pumped into the primary filtering cavity, dirt is precipitated in the primary filtering cavity, the precipitated dirt is accumulated in the filtering box and can be conveniently cleaned and replaced, supernate enters the secondary filtering cavity after submerging the middle partition plate and can be precipitated again in the secondary filtering cavity, and the secondary filtering effect is achieved. And finally, relatively clear water is pumped out, so that dirt is prevented from entering the pipeline to cause blockage.

Description

Technical Field

[0001] The invention belongs to the field of drainage devices, in particular to a centralized drainage device for a fully mechanized mining working face. Background Art

[0002] The centralized drainage technology of fully mechanized mining faces is an important part of coal mining. With the continuous transportation of coal and rock formations, goafs will be formed underground. These goafs will continue to gush water. If these accumulated water are not discharged in time, it will seriously affect the safe production and operating efficiency of the mine. In coal mining projects, due to the large number of mining faces, multiple water-filled channels are formed, resulting in continuous gush of water in the goafs. These accumulated waters bring challenges to the safe production of mines.

[0003] However, at present, the drainage system of the fully mechanized mining face mostly uses the direct drainage method of submersible pumps. Although this method is simple, due to the complex underground environment, impurities such as coal slime and rock cuttings can easily enter the drainage pipes, causing pipe blockage and affecting drainage efficiency. In addition, manual cleaning is required after the pipes are blocked, which increases the difficulty of operation and safety risks.

[0004] To this end, those skilled in the art have proposed a centralized drainage device for fully mechanized mining working faces to solve the problems raised by the background technology.

[0005] The above information disclosed in this background technology is only used to increase the understanding of the background technology of the present invention and therefore, it may include information that does not constitute the prior art known to ordinary technicians in this field. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a centralized drainage device for a fully mechanized mining working face to solve the problem in the prior art that dirt easily clogs the pipes.

[0007] To achieve the above-mentioned purpose, the present invention provides a centralized drainage device for a comprehensive mining working face, including a drainage intermediate box, the drainage intermediate box including a box body, both sides of the box body are respectively connected to a water inlet pipe and a drainage pipe, an intermediate partition is provided in the middle of the box body, and the intermediate partition divides the box body into a primary filter chamber and a secondary filter chamber; a primary filter element is provided in the primary filter chamber, and the primary filter element includes a filter box arranged in the box body, and a water inlet is provided on one side of the filter box, and the water inlet is connected to the water inlet pipe.

[0008] Preferably, the height of the middle partition is smaller than the height of the box body, and the height of the filter box is smaller than the height of the middle partition.

[0009] Preferably, a pressure plate is slidably connected to the top of the filter box, and both the pressure plate and the filter box can filter impurities in the water.

[0010] Preferably, a re-filter element is provided in the re-filter chamber, and the re-filter element includes a mounting plate fixed in the re-filter chamber, a re-filter plate is mounted on the mounting plate, and the re-filter plate is located above the drain pipe.

[0011] Preferably, it also includes a movable part, which includes tongue plates arranged at the four corners of the top of the filter box, a guide rod is fixedly connected to the lower surface of the tongue plate, the bottom end of the guide rod is connected to the bottom of the filter box, and the pressure plate is slidably connected to the guide rod.

[0012] Preferably, the movable part further comprises a rotating shaft arranged at the center of the pressure plate, the rotating shaft is rotatably connected to a rotating rod, and a limiting member is provided on the upper surface of the middle partition, and the limiting member is adapted to the rotating rod.

[0013] Preferably, the limiting member also includes a limiting block arranged on the upper surface of the middle partition, the limiting block is a frame structure, one end of the limiting block is provided with an opening, the top of the limiting block is provided with a cover plate, and the end of the limiting block away from the opening is fixedly connected to the middle partition.

[0014] Preferably, two rotating rods are provided, and the two rotating rods have the same size and shape. Two limit plates are provided on the top of the rotating shaft, and the two limit plates are respectively fitted with the upper and lower surfaces of the rotating rod.

[0015] Preferably, a accommodating box is provided on one side of the box body, the accommodating box is provided with an accommodating cavity, a telescopic block is slidably connected to the accommodating cavity, a spring is fixedly connected in the accommodating cavity, and the other end of the spring is fixedly connected to the telescopic block.

[0016] Preferably, the telescopic block is provided with a guiding inclined surface, the opening of the accommodating cavity is adapted to the telescopic block, and the portion of the telescopic block extending out of the box body has the same shape as the limiting block.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a primary filter chamber, a secondary filter chamber and a filter box. When in use, sewage is pumped into the primary filter chamber, and dirt is precipitated in the primary filter chamber. The precipitated dirt is accumulated in the filter box and can be easily cleaned and replaced. The supernatant passes through the middle partition and enters the secondary filter chamber, where it can be precipitated again. Finally, relatively clear water is pumped out to prevent dirt from entering the pipeline and causing blockage.

[0019] By arranging a pressure plate on the top of the filter box, both the pressure plate and the filter box can filter impurities in the water. The pressure plate can be pressed downward from the top of the filter box. The pressure plate is provided with the same filter holes as the filter box. The pressure plate covers the top of the filter box when pumping water into the filter box, and can block dirt under the pressure plate, thereby preventing dirt from entering the re-filtration chamber. The pressure plate can be pressed down as needed. For example, when cleaning the filter box, the pressure plate can be pressed down to press out the water in the filter box, and the volume used for sedimentation in the filter box can be changed according to the height of the pressure plate.

[0020] By arranging a re-filter chamber and a re-filter plate in the box body, the filter holes of the re-filter plate are smaller than the filter holes of the filter box and the pressure plate, so that finer filtration can be achieved. The mounting plate and the re-filter plate are placed above the drain pipe, so that the water passing through the middle partition needs to be filtered again by the re-filter plate before falling into the re-filter chamber, thereby further increasing the filtration effect. The filtered dirt accumulates on the re-filter plate, and can be easily cleaned and the filtration effect can be maintained by simply replacing the re-filter plate.

[0021] By setting a limit piece and a rotating rod, the telescopic block plays the same role as the limit piece when it is fully extended from the accommodating box. At this time, the other rotating rod is stuck in the telescopic block, so that force is applied to the pressure plate from both sides at the same time. When the filter box needs to be taken out, the telescopic block can be stored back in the accommodating box without affecting the use. By setting two rotating rods, force can be applied to the pressure plate from both sides at the same time, and the position of the pressure plate can be fixed during filtering to prevent the pressure plate from floating out of the filter box. In addition, the relative height of the pressure plate can be adjusted according to the different lengths of the rotating shaft. When the two rotating rods are moved out of the limit piece, the pressure plate can be moved out of the filter box and taken out separately for cleaning.

[0022] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of a centralized drainage device for a fully mechanized mining working face in an embodiment of the present invention;

[0024] Figure 2 It is a schematic cross-sectional structure diagram of a centralized drainage device for a fully mechanized mining working face in an embodiment of the present invention;

[0025] Figure 3 It is a cross-sectional front view schematic diagram of a centralized drainage device for a fully mechanized mining working face in an embodiment of the present invention;

[0026] Figure 4 for Figure 1 Enlarged view of point A in .

[0027] Figure 5 It is a structural schematic diagram of another embodiment of a centralized drainage device for a fully mechanized mining working face in an embodiment of the present invention.

[0028] Figure 6 for Figure 5 Enlarged view of point B.

[0029] Figure 7 It is a schematic diagram of the cross-sectional structure of a containing box of a centralized drainage device for a fully mechanized mining working face in an embodiment of the present invention.

[0030] In the figure:

[0031] 1. Drainage intermediate box; 11. Box body; 12. Water inlet pipe; 13. Drainage pipe; 14. Middle partition; 15. Primary filter chamber; 16. Secondary filter chamber; 2. Primary filter element; 21. Filter box; 22. Pressing plate; 23. Water inlet; 3. Secondary filter element; 31. Mounting plate; 32. Secondary filter plate; 4. Movable part; 41. Tongue plate; 42. Guide rod; 43. Rotating shaft; 44. Rotating rod; 5. Limiting part; 51. Limiting block; 511. Opening; 512. Cover plate; 52. Accommodating box; 521. Accommodating chamber; 522. Telescopic block; 523. Guide slope; 524. Spring;. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. It should be pointed out that the drawings are schematic and not drawn to scale. For the sake of clarity and convenience in the figures, the relative sizes and proportions of the parts shown in the figures are exaggerated or reduced in size, and any size is only exemplary and not restrictive.

[0033] Embodiment 1:

[0034] See also Figure 1 - Figure 2 As shown, a centralized drainage device for a comprehensive mining working face includes a drainage intermediate box 1, and the drainage intermediate box 1 includes a box body 11. The two sides of the box body 11 are respectively connected to a water inlet pipe 12 and a drainage pipe 13. An intermediate partition 14 is provided in the middle of the box body 11, and the intermediate partition 14 divides the box body 11 into a primary filter chamber 15 and a secondary filter chamber 16; a primary filter element 2 is provided in the primary filter chamber 15, and the primary filter element 2 includes a filter box 21 arranged in the box body 11, and a water inlet 23 is provided on one side of the filter box 21, and the water inlet 23 is connected to the water inlet pipe 12.

[0035] Specifically, the height of the middle partition 14 is less than the height of the box body 11, and the height of the filter box 21 is less than the height of the middle partition 14. The surface of the filter box 21 is provided with filter holes for water permeability and blocking dirt. The water inlet pipe 12 is connected to an external water pump, and the water pump pumps the accumulated water on the working surface into the drainage intermediate box 1. The sewage enters the drainage intermediate box 1 and first enters the filter box 21 through the water inlet 23. The dirt with higher density in the filter box 21 is first precipitated until the water level in the primary filter chamber 15 rises to the height of the middle partition 14. At this time, the supernatant liquid submerges the middle partition 14 and enters the re-filter chamber 16. In the re-filter chamber 16, a certain amount of precipitation can be carried out and the supernatant liquid is taken again for filtration. Finally, most of the dirt is filtered in the drainage intermediate box 1, reducing the dirt flowing in the pipeline and reducing the possibility of pipeline blockage.

[0036] As can be seen from the above, by setting the primary filter chamber 15, the secondary filter chamber 16 and the filter box 21, sewage is pumped into the primary filter chamber 15 during use, and the dirt is precipitated in the primary filter chamber 15. The precipitated dirt is accumulated in the filter box 21 and can be easily cleaned and replaced. The supernatant passes through the middle partition 14 and enters the secondary filter chamber 16, where it can be precipitated again, and finally clearer water is pumped out to prevent dirt from entering the pipeline and causing blockage.

[0037] Embodiment 2:

[0038] See also Figure 2 As shown, this embodiment is basically the same as the previous embodiment, except that a pressing plate 22 is slidably connected to the top of the filter box 21, and both the pressing plate 22 and the filter box 21 can filter impurities in the water.

[0039] Specifically, the pressure plate 22 can be pressed downward from the top of the filter box 21. The pressure plate 22 is provided with the same filter holes as the filter box 21. The pressure plate 22 covers the top of the filter box 21 when pumping water into the filter box 21, and can block dirt under the pressure plate 22, thereby preventing dirt from entering the re-filtration chamber 16, and the pressure plate 22 can be pressed down as needed. For example, when cleaning the filter box 21, the pressure plate 22 can be pressed down to press out the water in the filter box 21, and according to the height of the pressure plate 22, the volume used for sedimentation in the filter box 21 can be changed.

[0040] See also Figure 3 and Figure 4 As shown, further, it also includes a movable part 4, which includes a tongue plate 41 arranged at the four corners of the top of the filter box 21, and a guide rod 42 is fixedly connected to the lower surface of the tongue plate 41, and the bottom end of the guide rod 42 is connected to the bottom of the filter box 21, and the pressure plate 22 is slidably connected to the guide rod 42. By setting the guide rod 42, the pressure plate 22 is connected to the guide rod 42 to limit the sliding direction of the pressure plate 22 so that it can only slide up and down along the guide rod 42. The size of the tongue plate 41 is slightly larger, and at the same time it can play a limiting role to prevent the pressure plate 22 from floating out of the filter box 21.

[0041] The movable part 4 also includes a rotating shaft 43 arranged at the center of the pressure plate 22, and the rotating shaft 43 is rotatably connected to a rotating rod 44. A limit piece 5 is provided on the upper surface of the middle partition 14, and the limit piece 5 is adapted to the rotating rod 44. The rotating rod 44 rotates around the rotating shaft 43. After the rotating shaft 43 is rotated to a certain angle, it can be stuck in the limit piece 5, thereby fixing the height of the pressure plate 22.

[0042] As can be seen from the above, when long-term filtration is required, the rotating rod 44 can be rotated and the rotating rod 44 can be stuck in the limit piece 5. At this time, as the water level rises, the pressure plate 22 gradually floats up, but the tongue plate 41 and the limit piece 5 can hold the position of the pressure plate 22, and according to the different lengths of the rotating shaft 43, the height of the pressure plate 22 pressed down can be changed, thereby adjusting the position of the pressure plate 22. When it is necessary to control the pressure plate 22 to be pressed down, it is only necessary to rotate the rotating rod 44 to disengage it from the limit piece 5, and the pressure plate 22 can be pressed down to press the dirt to the bottom of the filter box 21.

[0043] Embodiment three:

[0044] See also Figure 2 As shown, this embodiment is basically the same as the previous embodiment, except that a re-filter element 3 is provided in the re-filter chamber 16, and the re-filter element 3 includes a mounting plate 31 fixed in the re-filter chamber 16, and a re-filter plate 32 is installed on the mounting plate 31, and the re-filter plate 32 is located above the drain pipe 13.

[0045] Specifically, the filter holes of the re-filter plate 32 are smaller than the filter holes of the filter box 21 and the pressure plate 22, and can perform finer filtering. The mounting plate 31 and the re-filter plate 32 are placed above the drain pipe 13, so that the water passing through the middle partition 14 needs to be filtered again by the re-filter plate 32 before falling into the re-filter chamber 16, thereby further increasing the filtering effect, and the filtered dirt accumulates on the re-filter plate 32, and only needs to replace the re-filter plate 32 to easily clean and maintain the filtering effect.

[0046] Embodiment 4:

[0047] See also Figure 5 and Figure 6 As shown, this embodiment is basically the same as the previous embodiment, except that the tongue plate 41 and the guide rod 42 are no longer provided, and the limit member 5 also includes a limit block 51 arranged on the upper surface of the middle partition 14, the limit block 51 is a frame structure, an opening 511 is provided at one end of the limit block 51, a cover plate 512 is provided on the top of the limit block 51, and the end of the limit block 51 away from the opening 511 is fixedly connected to the middle partition 14.

[0048] The opening 511 of the limit block 51 is used for the rotating rod 44 to enter. After the rotating rod 44 rotates and enters the limit block 51, as the pressure plate 22 floats up, it can be stuck inside the limit block 51, thereby limiting the floating of the pressure plate 22 and fixing the position of the pressure plate 22.

[0049] See also Figure 5 As shown, there are two rotating rods 44, and the two rotating rods 44 have the same size and shape. Two limit plates are provided on the top of the rotating shaft 43, and the two limit plates are respectively fitted with the upper and lower surfaces of the rotating rod 44. By setting the limit plates, the up and down movement of the rotating rod 44 can be limited, so that after the rotating rod 44 is stuck in the limit block 51, the pressure plate 22 can be pressed by the rotating shaft 43.

[0050] See also Figure 5 and Figure 7 As shown, a accommodating box 52 is provided on one side of the box body 11, and the accommodating box 52 is provided with a accommodating cavity 521. The accommodating cavity 521 is slidably connected to a telescopic block 522, and a spring 524 is fixedly connected in the accommodating cavity 521. The other end of the spring 524 is fixedly connected to the telescopic block 522. When the telescopic block 522 is fully extended out of the accommodating box 52, it plays the same role as the limit block 51. At this time, the other rotating rod 44 is stuck in the telescopic block 522, so as to apply force to the pressure plate 22 from both sides at the same time. When the filter box 21 needs to be taken out, the telescopic block 522 can be stored back in the accommodating box 52 without affecting the use.

[0051] The telescopic block 522 is provided with a guiding slope 523, and the opening 511 of the accommodating chamber 521 is adapted to the telescopic block 522. The portion of the telescopic block 522 extending out of the box body 11 has the same shape as the limiting block 51. The guiding slope 523 is provided at the bottom edge of the telescopic block 522. The guiding slope 523 can press the guiding slope 523 when the filter box 21 is lifted, and then the telescopic block 522 is pressed into the accommodating chamber 521. The telescopic block 522 compresses the spring 524. When the filter box 21 passes, the spring 524 pushes the telescopic block 522 out again.

[0052] By setting two rotating rods 44, force can be applied to the pressure plate 22 from both sides at the same time, so that the position of the pressure plate 22 can be fixed during filtering to prevent the pressure plate 22 from floating out of the filter box 21, and the relative height of the pressure plate 22 can be adjusted by setting different lengths of the rotating shaft 43. When the two rotating rods 44 move out of the limit piece 5, the pressure plate 22 can be moved out of the filter box 21, and the pressure plate 22 can be taken out separately for cleaning.

[0053] The standard parts used in the present invention can all be purchased from the market, and the special-shaped parts can be customized according to the description and the drawings. The specific connection methods of each part adopt conventional means such as mature bolts, rivets, welding, etc. in the prior art. The machinery, parts and equipment all adopt conventional models in the prior art, and the circuit connection adopts the conventional connection method in the prior art, which will not be described in detail here. The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0054] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0055] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0057] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0058] In the drawings of the embodiments disclosed in the present invention, only the structures related to the embodiments disclosed in the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other.

[0059] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A centralized drainage device for a fully mechanized mining working face, characterized in that: include, A drainage intermediate box (1), the drainage intermediate box (1) comprising a box body (11), the two sides of the box body (11) are respectively connected to a water inlet pipe (12) and a drainage pipe (13), a middle partition (14) is provided in the middle of the box body (11), and the middle partition (14) divides the box body (11) into a primary filter chamber (15) and a secondary filter chamber (16); A primary filter element (2) is arranged in the primary filter chamber (15), and the primary filter element (2) comprises a filter box (21) arranged in the box body (11). A water inlet (23) is arranged on one side of the filter box (21), and the water inlet (23) is connected to the water inlet pipe (12).

2. A centralized drainage device for fully mechanized mining working face according to claim 1, characterized in that: The height of the middle partition (14) is smaller than the height of the box body (11), and the height of the filter box (21) is smaller than the height of the middle partition (14).

3. A centralized drainage device for fully mechanized mining working face according to claim 2, characterized in that: A pressing plate (22) is slidably connected to the top of the filter box (21), and the pressing plate (22) and the filter box (21) are used to filter impurities in water.

4. A centralized drainage device for fully mechanized mining working face according to claim 3, characterized in that: A re-filter element (3) is arranged in the re-filter chamber (16), and the re-filter element (3) comprises a mounting plate (31) fixed in the re-filter chamber (16), a re-filter plate (32) is mounted on the mounting plate (31), and the re-filter plate (32) is located above the drain pipe (13).

5. A centralized drainage device for fully mechanized mining working face according to claim 4, characterized in that: The invention also comprises a movable part (4), wherein the movable part (4) comprises tongue plates (41) arranged at the four corners of the top of the filter box (21), a guide rod (42) being fixedly connected to the lower surface of the tongue plate (41), the bottom end of the guide rod (42) being connected to the bottom of the filter box (21), and the pressure plate (22) being slidably connected to the guide rod (42).

6. A centralized drainage device for fully mechanized mining working face according to claim 5, characterized in that: The movable member (4) further comprises a rotating shaft (43) arranged at the center of the pressure plate (22), the rotating shaft (43) being rotatably connected to a rotating rod (44), and a limiting member (5) is provided on the upper surface of the middle partition plate (14), and the limiting member (5) is adapted to the rotating rod (44).

7. A centralized drainage device for fully mechanized mining working face according to claim 6, characterized in that: The limiting member (5) further comprises a limiting block (51) arranged on the upper surface of the middle partition (14); the limiting block (51) is a frame structure; an opening (511) is arranged at one end of the limiting block (51); a cover plate (512) is arranged at the top of the limiting block (51); and an end of the limiting block (51) away from the opening (511) is fixedly connected to the middle partition (14).

8. A centralized drainage device for fully mechanized mining working face according to claim 7, characterized in that: Two rotating rods (44) are provided, and the two rotating rods (44) have the same size and shape. Two limiting plates are provided on the top of the rotating shaft (43), and the two limiting plates are respectively fitted with the upper and lower surfaces of the rotating rod (44).

9. A centralized drainage device for fully mechanized mining working face according to claim 8, characterized in that: A accommodating box (52) is provided on one side of the box body (11), the accommodating box (52) is provided with an accommodating cavity (521), a telescopic block (522) is slidably connected to the accommodating cavity (521), a spring (524) is fixedly connected inside the accommodating cavity (521), and the other end of the spring (524) is fixedly connected to the telescopic block (522).

10. A centralized drainage device for fully mechanized mining working face according to claim 9, characterized in that: The telescopic block (522) is provided with a guiding inclined surface (523), the opening (511) of the accommodating cavity (521) is adapted to the telescopic block (522), and the portion of the telescopic block (522) extending out of the box body (11) has the same shape as the limiting block (51).

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