Buckle structure of glue pouring box and ultrasonic water meter shell adopting buckle structure

Abstract

The utility model discloses a glue pouring box buckle structure and an ultrasonic water meter shell adopting the buckle structure. The glue pouring box buckle structure comprises a first clamping block assembly, a second buckle assembly and a third buckle assembly. The glue pouring box is connected with the lower shell of the ultrasonic water meter through a first clamping block assembly; the glue pouring box is connected with the circuit board through a second buckle assembly. The glue pouring box is connected with the cover plate through a third buckle assembly, and the cover plate is used for sealing and covering the upper opening of the glue pouring box. The ultrasonic water meter shell comprises an upper shell body, a lower shell body and a glue pouring box, a containing cavity is defined by the upper shell body and the lower shell body, and the glue pouring box is arranged in the containing cavity and connected with the lower shell body, the circuit board and the cover plate through the buckle structure. The connecting structure is reasonable in structure, convenient to disassemble and assemble and favorable for improving the assembly efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of ultrasonic water meters, in particular to a glue-filling box buckle structure and an ultrasonic water meter shell adopting the buckle structure. Background Art

[0002] With the development of society, the application of ultrasonic water meters in the water meter market is gradually replacing traditional mechanical water meters. They usually include upper and lower shells, which are arranged above the fluid channel. The upper and lower shells form a accommodating cavity that contains electronic components such as circuit boards, power supplies and communication modules. Usually, a glue potting box is also provided in the aforementioned accommodating cavity. Electronic components such as circuit boards are placed in the glue potting box and sealed with glue to improve the sealing reliability.

[0003] In production practice, screws are often used to secure the potting box, the circuit board, and the cover plate at the opening of the potting box. Screws come in a variety of sizes and are connected by setting corresponding threaded holes or self-tapping threads. This presents the following problems: 1) Screw connections require an electric screwdriver or automatic screw-driving equipment, which is inefficient. 2) Due to the small size and limited strength of the screws, an appropriate torque must be set, otherwise the threads are prone to stripping. 3) Plastic threaded holes are susceptible to stress, leading to cracking and breakage, resulting in connection failure. 4) The small size of the screws makes the screw coating easily detached and rusts. 5) If a screw breaks, the broken part cannot be removed, causing the entire housing to be scrapped, which is uneconomical. 6) The variety of screw types leads to an increase in production materials and increased costs for incoming materials and warehousing control. 7) When problems arise in subsequent processes and require repair, the screws need to be removed, which is very inconvenient. Self-tapping screws are particularly prone to stripping and connection failure due to repeated installation. Utility Model Content

[0004] This utility model discloses a snap-fit ​​structure for a glue-filling box and an ultrasonic water meter housing employing the snap-fit ​​structure. It solves the technical problems of the prior art, such as the cumbersome and inefficient operation of attaching and securing the glue-filling box to adjacent components, which is difficult to maintain and uneconomical. The utility model has a rational structure, facilitates assembly and disassembly, and improves assembly efficiency. The technical solution employed is as follows:

[0005] A snap-fit ​​structure for a glue-filling box, comprising a first snap-fit ​​assembly, a second snap-fit ​​assembly, and a third snap-fit ​​assembly;

[0006] The first buckle assembly includes a first plane limit assembly and a first upper and lower limit assembly, and the glue filling box is connected to the lower housing of the ultrasonic water meter through the first clamping block assembly;

[0007] The second buckle assembly includes a second plane limit assembly and a second upper and lower limit assembly, and the glue potting box is connected to the circuit board through the second buckle assembly;

[0008] The third buckle assembly includes a third plane limiting assembly and a third upper and lower limiting assembly. The glue pouring box is connected to the cover plate through the third buckle assembly. The cover plate is used to seal the upper opening of the glue pouring box.

[0009] Based on the above technical solution, the first plane limit assembly includes several first ribs arranged circumferentially, the first ribs are fixed on the lower shell of the ultrasonic water meter and are respectively connected to the bottom surface and side walls of the lower shell, the abutting surface of the first rib and the glue box includes an L-shaped end surface adapted to the outer edge surface of the glue box to support and limit the glue box; there are multiple first upper and lower limit assemblies and they are arranged circumferentially, the first upper and lower limit assemblies include a first card slot and a first card block, the first card slot and the first card block are arranged in corresponding positions and are respectively fixed on the outer wall surface of the glue box and the inner wall surface of the lower shell of the ultrasonic water meter.

[0010] On the basis of the above technical solution, the first card block and the first card slot are clearance-matched in the width direction of the first card block to horizontally limit the glue potting box, and the outer end surface of the first card block facing the glue potting box has an angle inclined outward from bottom to top to facilitate the first card block to be engaged into the first card slot; and the first card slot is designed so that when the first card block is engaged into the first card slot, the bottom surface of the glue potting box contacts the first rib.

[0011] Based on the above technical solution, the second plane limiting assembly includes a plurality of positioning posts fixed in the glue potting box, and the positioning posts can be embedded in the groove on the outer edge surface of the circuit board to limit the circuit board in the plane direction. The second upper and lower limiting assemblies include a plurality of second upper clips and a plurality of second lower clips. The plurality of second upper clips are fixed in the glue potting box and arranged circumferentially to contact the circuit board downward, and the plurality of second lower clips are fixed in the glue potting box and arranged circumferentially to contact the circuit board upward.

[0012] Based on the above technical solution, the outer end surface of the second upper clip facing the circuit board has an angle inclined outward from bottom to top, and the abutting surface of the second lower clip and the circuit board includes an L-shaped end surface adapted to the outer edge surface of the circuit board to support and limit the circuit board.

[0013] Based on the above technical solution, at least two of the second lower clips extend upward to be flush with the top surface of the glue potting box, and the upper end surface of the second lower clip facing the circuit board has an angle inclined inward from top to bottom to guide the circuit board into the glue potting box.

[0014] On the basis of the above technical solution, the third plane limiting assembly includes a number of third ribs fixed in the glue pouring box, and the number of the third ribs are arranged circumferentially and can abut against the outer edge surface of the cover plate to position the cover plate in the plane direction; the third upper and lower limiting assembly includes a number of third upper clips and a number of third lower clips, and the number of the third upper clips are fixed in the glue pouring box and arranged circumferentially to contact the cover plate downward, and the number of the third lower clips are fixed in the glue pouring box and arranged circumferentially to contact the cover plate upward.

[0015] Based on the above technical solution, the second lower buckle forms a third rib to position the cover in the planar direction, and the second upper buckle forms a third lower buckle, and the outer end surface of the third upper buckle facing the cover has an angle inclined from bottom to top and outward.

[0016] An ultrasonic water meter housing includes an upper housing, a lower housing, and a glue potting box. The upper housing and the lower housing are detachably connected and enclosed to form an accommodating cavity. The glue potting box is arranged in the accommodating cavity and is respectively connected to the lower housing, the circuit board, and the cover plate through the snap-fit ​​structure as described above.

[0017] Based on the above technical solution, the upper shell and the lower shell are connected by screws, the inner wall surface of the lower shell is provided with a lower convex portion, and the lower convex portion is formed with a lower threaded hole, the inner wall surface of the upper shell is provided with an upper convex portion, and the upper convex portion is provided with an upper threaded hole, and the outer edge surface of the glue filling box avoids the lower convex portion and the upper convex portion.

[0018] Beneficial effects

[0019] The utility model has a reasonable structure. The glue filling box adopts multiple snap-fit ​​components to realize assembly connection with the lower shell, circuit board and cover plate of the ultrasonic water meter respectively, which not only has high assembly operation efficiency, but also reduces the use of connecting parts such as screws, avoiding the use risks caused by the use of connecting parts. At the same time, it is convenient for disassembly and assembly, and convenient for subsequent inspection and maintenance, which is conducive to improving assembly efficiency and reducing labor labor.

[0020] The design of multiple snap assemblies in this utility model facilitates their integrated placement on the glue potting box, which not only improves the structural strength of the glue potting box, but also the structural strength of the snap assemblies themselves. Furthermore, the snap assemblies can be positioned not only in the plane but also vertically, effectively preventing the glue potting box, circuit board, or cover from shaking after assembly, thereby improving structural stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other implementation drawings can be derived from the provided drawings without inventive effort.

[0022] Figure 1 : Schematic diagram of the explosion structure of the ultrasonic water meter housing in the utility model;

[0023] Figure 2 : Schematic diagram of the three-dimensional structure of the ultrasonic water meter housing after removing the upper housing in the utility model;

[0024] Figure 3 : Schematic diagram of the three-dimensional structure of the lower shell of the utility model;

[0025] Figure 4 : Schematic diagram of the three-dimensional structure of the glue filling box in this utility model Figure 1 ;

[0026] Figure 5 : Schematic diagram of the three-dimensional structure of the glue filling box in this utility model Figure 2 ; DETAILED DESCRIPTION

[0027] The following description and accompanying drawings sufficiently illustrate the specific embodiments herein to enable those skilled in the art to practice them. Portions and features of some embodiments may be included in or substituted for portions and features of other embodiments. The scope of the embodiments herein includes the entire scope of the claims, including all available equivalents thereof. Herein, the terms "first," "second," and the like are used solely to distinguish one element from another and do not require or imply any actual relationship or order between these elements. In practice, the first element can also be referred to as the second element, and vice versa. Furthermore, the terms "comprise," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a structure, device, or apparatus comprising a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such structure, device, or apparatus. Without further limitation, an element defined by the phrase "comprising a..." does not preclude the presence of other identical elements in the structure, device, or apparatus comprising the element. The various embodiments herein are described in a progressive manner, with each embodiment focusing on its differences from the other embodiments. Similar or identical parts between the various embodiments can be referenced to each other.

[0028] The terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used herein to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are intended only to facilitate the description of this document and simplify the description, and are not intended to 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 should not be construed as a limitation on the present invention. In the description herein, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, they can be mechanical or electrical connections, or they can be internal connections between two elements, they can be directly connected, or they can be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0029] As used herein, unless otherwise specified, the term "plurality" means two or more.

[0030] In this document, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0031] In this article, the term "and / or" is used to describe the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or, A and B.

[0032] like Figure 1 As shown, in this embodiment, the ultrasonic water meter includes an upper shell 1 and a lower shell 2 , and the glue filling box 3 is arranged in a receiving cavity enclosed by the upper shell 1 and the lower shell 3 .

[0033] like Figures 2 to 5 The buckle structure of a glue-filling box shown includes a first clamping block assembly, a second buckle assembly and a third buckle assembly;

[0034] The first buckle assembly includes a first plane limit assembly 101 and a first upper and lower limit assembly 102, and the glue box 3 is connected to the lower housing 2 of the ultrasonic water meter through the first clamping block assembly; Figure 3 As shown, the first plane limit assembly 101 includes a plurality of first ribs arranged circumferentially. The first ribs are fixed to the lower shell 2 of the ultrasonic water meter and are respectively connected to the bottom surface and side walls of the lower shell 2, which is beneficial to enhancing the structural strength of the lower shell 2 and the structural strength of the first ribs themselves. In this embodiment, the lower shell 2 and the first ribs are made of plastic and are integrally formed to simplify the process. Figure 3 As shown, the contact surface between the first rib and the glue potting box 3 includes an L-shaped end surface adapted to the outer edge surface at the corresponding position of the glue potting box 3, so as to support and limit the glue potting box 3 left and right and front and back;

[0035] There are multiple first upper and lower limit assemblies 102 and they are arranged circumferentially, such as Figure 2 and 3 As shown, the first upper and lower limit assembly 102 includes a first card slot 1021 and a first card block 1022. The first card slot 1021 and the first card block 1022 are arranged in a corresponding position, wherein the first card slot 1021 is fixed on the outer wall surface of the glue filling box 3 and is integrally formed with the glue filling box 3, and the first card block 1022 is fixed on the inner wall surface of the lower shell 2 and is integrally formed with the lower shell 2; wherein the first card block 1022 and the first card slot 1021 are spaced apart in the width direction of the first card block 1022. On the one hand, it is convenient for smooth engagement, and on the other hand, it can also horizontally limit the glue potting box 3 to improve reliability; in addition, the outer end surface of the first clamping block 1022 facing the glue potting box 3 has an angle inclined outward from bottom to top, so as to guide the first clamping block 1022 to be engaged into the first clamping groove 1021; at the same time, the first clamping groove 1021 is designed so that when the first clamping block 1022 is engaged into the first clamping groove 1021, the bottom surface of the glue potting box 3 contacts the first rib, so that the glue potting box 3 can be prevented from shaking up and down after assembly.

[0036] like Figure 4 and 5 As shown, the second snap assembly includes a second plane limit assembly 201 and a second upper and lower limit assembly 202, and the glue potting box 3 is connected to the circuit board through the second snap assembly; specifically, the second plane limit assembly 201 includes three positioning columns fixed in the glue potting box 3, and the positioning columns are fixed downward on the inner bottom surface of the glue potting box 3, one of the positioning columns is arranged close to one end of the circuit board, and the other two positioning columns are arranged close to the other end of the circuit board. An arc-shaped groove is provided at the corresponding position of the outer edge surface of the circuit board, so that the positioning column can be embedded in the groove of the outer edge surface of the circuit board to limit the circuit board in the plane direction. In addition, a gap is left between the fixed position and the inner wall surface of the glue potting box to facilitate the removal and placement of the circuit board.

[0037] The second upper and lower limit components 202 include a plurality of second upper buckles 2021 and a plurality of second lower buckles 2022. The plurality of second upper buckles 2021 are fixed on the bottom surface of the glue potting box 3 and arranged circumferentially to contact the circuit board downward. Figure 4 As shown, the outer end surface of the second upper buckle 2021 facing the circuit board has an angle inclined outward from bottom to top to guide the circuit board to be engaged between the second upper buckle 2021 and the second lower buckle 2022 .

[0038] Several second lower clips 2022 are fixedly mounted within the glue potting box 3 and arranged circumferentially. The contact surfaces between the second lower clips and the circuit board include L-shaped end surfaces that mate with the outer edge of the circuit board to support and position the circuit board. Specifically, three of the second lower clips 2022 connect the inner bottom surface of the glue potting box 3 with the positioning post, thereby limiting the circuit board and improving the structural strength of the positioning post, resulting in a sophisticated structure. Furthermore, multiple second lower clips 2022 connect the bottom and side surfaces of the glue potting box 3 and extend upward to be flush with the top surface of the glue potting box 2. The upper end surfaces of the second lower clips 2022 facing the circuit board are inclined inward from top to bottom to guide the circuit board into the glue potting box, facilitating assembly operations and improving assembly quality.

[0039] The third snap assembly includes a third plane limit assembly 301 and a third upper and lower limit assembly 302. The cover plate 5 is arranged above the circuit board. The glue potting box 3 is connected to the cover plate 5 through the third snap assembly. The cover plate 5 is used to seal the opening on the glue potting box 3 to protect the circuit board.

[0040] The third plane limiting assembly 301 includes a plurality of third ribs fixedly mounted in the glue potting box 3. The plurality of third ribs are arranged circumferentially and can abut against the outer edge of the cover plate 5 to position the cover plate 5 in the plane direction. In this embodiment, the second lower clip 2022 having a substantially L-shape forms the third rib to simplify the structure and process.

[0041] The third upper and lower limit assembly 302 includes a plurality of third upper buckles 3021 and a plurality of third lower buckles 3022. The plurality of third upper buckles 3021 are fixed on the inner wall surface of the glue filling box 3 and are arranged circumferentially to contact the cover plate 5 downward. The outer end surface of the third upper buckle 3021 facing the cover plate 5 has an angle inclined from bottom to top and outward to guide the cover plate 5 to be engaged between the third upper buckle 3021 and the third lower buckle 3022.

[0042] Several third lower clips 3022 are fixedly mounted within the glue potting box 3 and arranged circumferentially to contact the cover plate upward. In this embodiment, the second upper clips 2021 form the third lower clips 3022. That is, the top surface of the second upper clips 2021 can contact the bottom surface of the cover plate 5 to support the cover plate 5. In addition, the top surface of the positioning column can also contact the bottom surface of the cover plate to support the cover plate 5.

[0043] like Figure 1 and 2 The ultrasonic water meter housing shown includes an upper housing 1, a lower housing 2 and a glue potting box 3. The upper housing 1 and the lower housing 2 are square in shape. The upper housing 1 and the lower housing 2 are detachably connected and enclosed to form an accommodating cavity. The glue potting box 3 is arranged in the accommodating cavity and is respectively connected to the lower housing 2, the circuit board and the cover plate 5 through the snap-fit ​​structure as described above.

[0044] like Figure 1 and 3As shown, the upper shell 1 and the lower shell 2 are connected by screws arranged at the four corners. The inner wall surface of the lower shell 2 is provided with a lower convex portion 21, and the lower convex portion 21 is formed with a lower threaded hole. The inner wall surface of the upper shell 1 is provided with an upper convex portion, and the upper convex portion is provided with an upper threaded hole or a countersunk hole. The outer edge surface of the glue filling box 3 avoids the lower convex portion 21 and the upper convex portion.

[0045] Assembly process

[0046] First, insert one end of the circuit board into the positioning post, and place the circuit board between the second upper clip 2021 and the second lower clip 2022. Press the other end of the circuit board so that the circuit board is inserted into the other two positioning posts, and at the same time, insert the other end of the circuit board between the second upper clip 2021 and the second lower clip 2022 at the corresponding position to complete the circuit board assembly.

[0047] Afterwards, place the cover plate 5 in the concave cavity formed by several third ribs, then place one end of the cover plate 5 between the third upper clip 3021 and the third lower clip 3022 at the corresponding position, press the other end of the cover plate 5 so that the cover plate 5 is snapped into the third upper clip 3021 and the third lower clip 3022 at the corresponding position, and complete the assembly of the cover plate 5.

[0048] Afterwards, place the assembled glue potting box 3, circuit board and cover plate 5 in the concave cavity enclosed by several first ribs, then place one end of the glue potting box between the first upper buckle 1021 and the first lower buckle 1022 at the corresponding position, press the other end of the glue potting box 3 so that the glue potting box 3 is snapped into the first upper buckle 1021 and the first lower buckle 1022 at the corresponding position, and complete the assembly of the glue potting box 3.

[0049] The present invention is described above by way of examples, but the present invention is not limited to the above specific embodiments. Any changes or modifications based on the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A snap-fit ​​structure for a glue-filling box, characterized in that: It includes a first buckle assembly, a second buckle assembly and a third buckle assembly; The first buckle assembly comprises a first plane limit assembly (101) and a first upper and lower limit assembly (102); the glue filling box (3) is connected to the lower housing (2) of the ultrasonic water meter via the first clamping block assembly; The second snap assembly comprises a second plane limiting assembly (201) and a second upper and lower limiting assembly (202), and the glue potting box (3) is connected to the circuit board via the second snap assembly; The third snap assembly comprises a third plane limiting assembly (301) and a third upper and lower limiting assembly (302). The glue potting box (3) is connected to the cover plate (5) via the third snap assembly. The cover plate (5) is used to seal the upper opening of the glue potting box (3).

2. The snap-fit ​​structure of the glue-filling box according to claim 1, characterized in that: The first plane limiting assembly (101) comprises a plurality of first ribs arranged circumferentially, the first ribs being fixedly mounted on the lower shell (2) of the ultrasonic water meter and respectively connected to the bottom surface and side walls of the lower shell (2), the abutting surface of the first ribs with the glue potting box (3) comprising an L-shaped end surface adapted to the outer edge surface of the glue potting box (3) to support and limit the glue potting box (3); the first upper and lower limiting assemblies (102) are provided in plurality and arranged circumferentially, the first upper and lower limiting assemblies comprising a first card slot (1021) and a first card block (1022), the first card slot (1021) and the first card block (1022) being arranged in corresponding positions and respectively fixedly mounted on the outer wall surface of the glue potting box (3) and the inner wall surface of the lower shell (2) of the ultrasonic water meter.

3. The snap-fit ​​structure of the glue-filling box according to claim 2, characterized in that: The first clamping block (1022) and the first clamping slot (1021) are clearance-matched in the width direction of the first clamping block (1022) to horizontally limit the glue potting box (3), and the outer end surface of the first clamping block (1022) facing the glue potting box (3) has an angle inclined from bottom to top and outward to facilitate the first clamping block (1022) to be clamped into the first clamping slot (1021); and the first clamping slot (1021) is designed so that when the first clamping block (1022) is clamped into the first clamping slot (1021), the bottom surface of the glue potting box (3) contacts the first rib.

4. The snap-fit ​​structure of the glue-filling box according to claim 1, characterized in that: The second plane limiting assembly (201) includes a plurality of positioning posts fixed in the glue potting box, and the positioning posts can be embedded in the grooves on the outer edge surface of the circuit board to limit the circuit board in the plane direction. The second upper and lower limiting assembly (202) includes a plurality of second upper buckles (2021) and a plurality of second lower buckles (2022). The plurality of second upper buckles (2021) are fixed in the glue potting box (3) and arranged circumferentially to contact the circuit board downwardly, and the plurality of second lower buckles (2022) are fixed in the glue potting box (3) and arranged circumferentially to contact the circuit board upwardly.

5. The snap-fit ​​structure of the glue-filling box according to claim 4, characterized in that: The outer end surface of the second upper buckle (2021) facing the circuit board has an angle inclined outward from bottom to top, and the contact surface of the second lower buckle (2022) with the circuit board includes an L-shaped end surface adapted to the outer edge surface of the circuit board to support and limit the circuit board.

6. The snap-fit ​​structure of the glue-filling box according to claim 5, characterized in that: At least two oppositely arranged second lower buckles (2022) extend upwards to be flush with the top surface of the glue potting box (3), and the upper end surfaces of the second lower buckles (2022) facing the circuit board have an angle inclined inward from top to bottom, so as to guide the circuit board to be placed in the glue potting box (3).

7. The snap-fit ​​structure of the glue-filling box according to claim 5 or 6, characterized in that: The third plane limiting assembly (301) comprises a plurality of third ribs fixedly mounted in the glue potting box, wherein the plurality of third ribs are arranged circumferentially and can abut against the outer edge surface of the cover plate (5) to position the cover plate (5) in the plane direction; the third upper and lower limiting assembly (302) comprises a plurality of third upper buckles (3021) and a plurality of third lower buckles (3022), wherein the plurality of third upper buckles (3021) are fixedly mounted in the glue potting box and arranged circumferentially to contact the cover plate (5) downward, and the plurality of third lower buckles (3022) are fixedly mounted in the glue potting box (3) and arranged circumferentially to contact the cover plate (5) upward.

8. The snap-fit ​​structure of the glue-filling box according to claim 7, characterized in that: The second lower buckle (2022) forms a third rib to position the cover plate (5) in a planar direction, the second upper buckle (2021) forms a third lower buckle (3022), and the outer end surface of the third upper buckle (3021) facing the cover plate (5) has an angle inclined outward from bottom to top.

9. An ultrasonic water meter housing, characterized in that: The invention comprises an upper shell (1), a lower shell (2) and a glue potting box (3), wherein the upper shell (1) and the lower shell (2) are detachably connected and enclosed to form a receiving cavity, and the glue potting box (3) is arranged in the receiving cavity and is respectively connected to the lower shell (2), the circuit board and the cover plate (5) through the snap-fit ​​structure according to any one of claims 1 to 6.

10. The ultrasonic water meter housing according to claim 9, characterized in that: The upper shell (1) and the lower shell (2) are connected by screws. The inner wall surface of the lower shell (2) is provided with a lower convex portion (21), and the lower convex portion (21) is formed with a lower threaded hole. The inner wall surface of the upper shell (1) is provided with an upper convex portion, and the upper convex portion is provided with an upper threaded hole. The outer edge surface of the glue filling box (3) avoids the lower convex portion and the upper convex portion.

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