Preschool education enlightenment metronome for music teaching

Abstract

The invention relates to a preschool education enlightenment metronome for music teaching, and the metronome is provided with a beat display part which comprises a hollow stand column, the stand column is internally provided with a sliding body and an electromagnet from top to bottom, the sliding body is vertically installed in the stand column in a sliding manner through guide blocks at two sides, and the stand column is internally connected with a first pressing sounder through a suspension coil spring. A magnet is installed in the sliding body, an electromagnet is clamped and fixed below the supporting ring through a pair of threaded rings, and the lower end of the lower supporting ring is connected with a second pressing sounder; a piston rod is coaxially fixed at the upper end of the sliding body, and a connecting rod is coaxially fixed at the lower end of the sliding body; a cross-shaped part is axially inserted into a top end opening of the stand column, and the two ends of the cross-shaped part are each provided with an elastic rubber sheet capable of expanding and deforming towards the outer side; after the electromagnet is electrified, three-gear magnetic force can be achieved, the sliding body is pushed to move upwards by different positions, different sound effects and actions are triggered, and the effect of rhythm sound and visual double experience is achieved.

Description

Technical Field

[0001] This invention relates to the field of metronome technology, specifically to a metronome for early childhood music education. Background Technology

[0002] A metronome is a device or software tool that accurately produces a fixed beat. It primarily sets the rhythm based on stable time intervals and uses regular sounds (such as a "tick") or visual cues like swaying or flashing to clearly indicate the tempo and rhythmic divisions, helping users maintain a stable and accurate rhythm during musical activities such as playing instruments and singing. For instrument learners, whether studying piano, guitar, violin, or other instruments, or vocal students practicing singing, a metronome helps them accurately grasp rhythm, avoiding inconsistent tempo and thus solidly improving their playing and singing skills.

[0003] For early childhood music education, there is currently no dedicated metronome. Most metronomes are professional metronomes designed and used based on the accurate mastery of rhythm. However, early childhood music education does not require a high level of accurate mastery of rhythm. Instead, it focuses on cultivating interest and providing an intuitive and initial perception of rhythm. Traditional metronomes have relatively simple shapes and structures and a single form of expression, which are not attractive to young children. Moreover, young children cannot perceive rhythm as directly and accurately as adults through sound alone, resulting in poor teaching effectiveness. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a metronome for early childhood music education that can trigger different sound effects and movements to achieve a dual experience of sound and visual rhythm, thereby solving the problems mentioned in the background art.

[0005] This invention is achieved through the following technical solution: A metronome for early childhood music education, comprising a metronome body, with a beat display component fixed on each side of the metronome body. Each beat display component includes a hollow column, inside which a slider and an electromagnet are arranged from top to bottom. The slider is vertically slidably mounted in a vertical groove on the inner wall of the column via guide blocks on both sides. A first pressing sound generator is connected to the upper part of the vertical groove via a suspension spring. A magnet is installed inside the slider. The electromagnet is fixed below a support ring via a pair of threaded rings. The lower end of the support ring is connected to a second pressing sound generator. The upper end of the slider abuts against the inner wall of the top of the column via a pressure-resistant spring, so that the slider is normally positioned above the support ring. A piston rod is coaxially fixed to the upper end of the slider, and the lower end... A connecting rod is coaxially fixed, and a limit plate is connected to the bottom end of the connecting rod; a cross-shaped part is axially inserted into the top port of the column, and each end of the cross-shaped part is provided with an elastic rubber sheet that can expand and deform outward; when the electromagnet is energized, it can have three levels of magnetic force. At the low level of magnetic force, it can push the sliding body to move up to the position where the limit plate and the second pressing sound device are pressed and contacted, so that the second pressing sound device can make a sound; at the medium level of magnetic force, it can also push the sliding body to move up to the position where the guide block and the first pressing sound device are pressed and contacted, so that both the first pressing sound device and the second pressing sound device can make a sound; at the high level of magnetic force, it can also push the sliding body to move up to the position where the suspension spring is compressed, so that when the piston rod moves up, its piston column can push the airflow in the cross-shaped part to squeeze the elastic rubber sheet, so that the elastic rubber sheet bulges outward into a spherical shape.

[0006] Furthermore, the connecting rod is axially slidably inserted into a seat tube. The bottom end of the seat tube is fixed to the center of the limiting plate, and the top end of the connecting rod is slidably inserted into it. The insertion end of the connecting rod has a guide frustum, which is axially slidably installed inside the seat tube. The guide frustum and the inner wall of the top end of the seat tube are in contact through a pressure spring. When the electromagnet has a low magnetic force, the connecting rod and the seat tube move axially synchronously. When the electromagnet has a medium magnetic force, the connecting rod can slide upward relative to the seat tube. Before the piston rod moves upward to its limit in the cross section, the pressure spring is still in a state that can continue to be compressed.

[0007] Furthermore, the cross-shaped part includes a plug-in post axially inserted into the top port of the column, and a horizontal extension integrally formed on both sides of the upper part of the plug-in post. The top of the plug-in post is hemispherical. The plug-in post has a smooth hole section and an inner expansion hole section coaxially connected from top to bottom. The diameter of the inner expansion hole section is larger than that of the smooth hole section. Under normal conditions, the piston post is located at the bottom end of the inner expansion hole section. When the piston post is inserted into the smooth hole section, it compresses the air in the smooth hole section to push the elastic rubber to expand and deform.

[0008] Furthermore, the sidewall of the inner expansion section has several ventilation holes.

[0009] Furthermore, the top of the smooth hole segment is connected to the center of the horizontal tube installed in the two horizontal extensions, and the two ends of the horizontal tube each pass through a sealing plate and enter the closed space enclosed by the elastic rubber and the sealing plate.

[0010] Furthermore, the end of the horizontal extension section is tapered, and the inner wall of the port of the horizontal extension section has an annular stop; the sealing plate is disc-shaped and is coaxially threaded and installed in the horizontal extension section, and the edge of the elastic rubber is firmly pressed against the inner wall of the stop.

[0011] Furthermore, the elastic rubber expands and deforms into a gourd shape.

[0012] Furthermore, it also includes a current controller that can adjust the current of the electromagnet to achieve adjustment of three levels of magnetic force.

[0013] Furthermore, both the first and second press-activated sound generators are airbags with whistles, and the two airbags produce different sounds.

[0014] Furthermore, a base plate is fixed on each side of the metronome body, and the column is fixed on the upper surface of the center of the base plate.

[0015] The beneficial effects of this invention are as follows: This music teaching metronome for early childhood education uses a metronome with an added beat display to present the beat not only in sound form but also by showing the strength of the beat through the inflating of elastic rubber. This makes the beat visible to the naked eye, with extremely rich expressive forms, easily capturing children's attention and enhancing their learning interest.

[0016] Specifically, in this invention, three levels of magnetic force are used, each corresponding to the sound emitted by the second pressing sound device, which can represent a weak beat. At the medium level of magnetic force, both pressing sound devices emit sound, which can represent a secondary strong beat. At the high level of magnetic force, not only do the pressing sound devices emit sound, but the elastic rubber at both ends also expands and bulges, thus representing a strong beat in a combined sound and visual way. This allows children to experience the changes in rhythm more intuitively.

[0017] Furthermore, this invention can be directly applied to existing metronomes, and when in use, the original beat sound of the metronome itself can be turned off, or the two can be used together to enrich the forms of beat music and avoid the monotony and distortion caused by using only electronic sounds.

[0018] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0019] Figure 1 This is a front view of the music teaching metronome for early childhood education according to the present invention; Figure 2 This is a left view of the music teaching metronome for early childhood education according to the present invention; Figure 3 This is a partial cross-sectional view of the beat display component of the present invention; Figure 4 When the magnetic force is low, a partial structural diagram of the beat display component is shown. Figure 5 When the magnetic force is medium, a partial structural diagram of the beat display component is shown. Figure 6 When the magnetic force is high, a partial structural diagram of the beat display component is shown. Figure 7 For the present invention Figure 5 A magnified view of the area at point K.

[0020] In the diagram: 1. Metronome body; 2. Metronome display component; 3. Base plate; 4. Column; 5. Vertical groove; 6. Sliding body; 7. Magnet; 8. Guide block; 9. Support ring; 10. Threaded ring; 11. Electromagnet; 12. Connecting rod; 13. Limiting disc; 14. Pressure-bearing coil spring; 15. Guide frustum; 16. Press-to-produce sound device; 17. Suspension coil spring; 18. Pressure-resistant coil spring; 18. Cross section; 1801. Insertion post; 1802. Horizontal extension section; 180201. Stop section; 19. Piston rod; 20. Piston column; 21. Seat tube; 22. Inner expansion section; 23. Smooth hole section; 24. Horizontal tube; 25. Elastic rubber; 26. Sealing disc. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] Please see Figures 1-2 This invention provides a technical solution: a metronome for early childhood music education, mainly comprising a metronome body 1. The metronome body 1 can emit electronic or mechanical sounds of rhythm, and can be any existing metronome. The difference is that, as a metronome for early childhood education, in order to capture children's attention and stimulate their interest, this embodiment also specifically includes a rhythm display component 2 fixed on each side of the metronome body 1. This rhythm display component 2 is mainly used to visually demonstrate the actual actions matching the rhythm, and also includes a press-to-produce sound device 15 to assist in displaying additional sounds. Specifically, as... Figure 3 The beat display component 2 includes a hollow column 4, and a base plate 3 is fixed on each side of the metronome body 1. The column 4 is fixed on the upper surface of the center of the base plate 3.

[0025] In specific implementation, such as Figure 3 Inside the column 4, from top to bottom, there are a sliding body 5 and an electromagnet 10. Guide blocks 7 are installed on both sides of the sliding body 5. The guide blocks 7 are vertically slidably installed in the vertical groove 401 on the inner side wall of the column 4, and the two are slidably connected. In addition, at the upper part of the vertical groove 401, the first pressing sound device 15 of the above-mentioned volume pressing sound device 15 is connected by a suspension spring 16. That is, a cylindrical elastic with a high stiffness coefficient and vertical setting is used to connect the first pressing sound device 15. Its stiffness coefficient should be such that the first pressing sound device 15 is stable in its normal position. A magnet 6 is installed inside the sliding body 5. An electromagnet 10 is clamped and fixed below the support ring 8 by a pair of threaded rings 9. The threaded rings 9 are threaded into the column 4, clamping the electromagnet 10 between them, thus fixing the electromagnet 10 in place. Simultaneously, the installation position of the threaded rings 9 can be pre-adjusted to initially adjust the repulsive force of the electromagnet 10 on the magnet 6, determining the force of the squeezing and impact between the limiting plate 12 (mentioned later) and the corresponding pressing sound generator 15 after energization, thereby changing the sound volume. On the other hand, in a specific implementation, the lower end of the lower support ring 8 is connected to the second pressing sound generator 15 to achieve the installation of the second pressing sound generator 15. The upper end of the sliding body 5 is connected to the inner wall of the top of the column 4 by a pressure-resistant round spring 17, so that the sliding body 5 is normally located at the upper end of the support ring 8, while the sliding body 5 is elastically slidably installed inside the column 4. A piston rod 19 is coaxially fixed to the upper end of the sliding body 5, and the piston rod 19 slides vertically. A connecting rod 11 is coaxially fixed to the lower end of the sliding body 5, and the bottom end of the connecting rod 11 is connected to a limit plate to follow the movement of the sliding body 5. Figure 3In this embodiment, a cross-shaped part 18 is axially inserted into the top port of the column 4. Each end of this cross-shaped part 18 has an elastic rubber sheet 25 that can expand and deform outwards. When the electromagnet 10 is energized, adjusting the corresponding knob allows the electromagnet 10 to have three levels of magnetic force. Specifically, at the low magnetic force level, such as... Figure 4 This can push the slider 5 upwards to the position where the limiting plate and the second pressing sound device 15 are in contact, so that the second pressing sound device 15 produces a sound. At medium magnetic force, such as... Figure 5 It can also push the slider 5 upward to the position where the guide block 7 and the first pressing sound generator 15 are in contact, at which point both the first pressing sound generator 15 and the second pressing sound generator 15 will produce sound. In high-level magnetic force, such as Figure 6 It can also push the slider 5 to move up to the position where the suspension spring 16 is compressed, so that when the piston rod 19 moves up, its piston column 20 can push the airflow in the cross part 18 to squeeze the elastic rubber 25, so that the elastic rubber 25 bulges outward into a spherical shape.

[0026] In this embodiment, as Figures 3-4 As shown, the connecting rod 11 is axially slidably inserted into a seat tube 21. The bottom end of the seat tube 21 is fixed to the center of the limiting plate 12, and the top end is for the bottom end of the connecting rod 11 to slide into. The insertion end of the connecting rod 11 has a guide frustum 14. The guide frustum 14 is axially slidably installed in the seat tube 21. The guide frustum 14 and the inner wall of the top end of the seat tube 21 are in contact through a pressure spring 13. Relying on the pushing force of the pressure spring 13, the connecting rod 11 and the seat tube 21 are temporarily kept as a whole and can move together as a whole. The elastic force of the aforementioned bearing spring 13 must satisfy the following conditions: when the electromagnet 10 is in a low magnetic force setting, the connecting rod 11 and the seat tube 21 move axially synchronously, i.e., the whole unit moves together; while in a medium magnetic force setting, the connecting rod 11 can slide upward relative to the seat tube 21, i.e., the connecting rod 11 slides axially relative to the seat tube 21. During this process, the piston rod 20 moves in the inner expansion section 22 mentioned below, and preferably does not enter the smooth section 23. When the magnetic force is in a high magnetic force setting, when the piston rod 20 moves upward to its limit in the cross section 18, the bearing spring 13 is still in a state that can continue to compress, to ensure that the piston rod 20 can move upward to the set position to achieve the inflation and expansion of the elastic rubber 25.

[0027] In this embodiment, as Figure 6As shown, the cross section 18 includes an insertion post 1801 axially inserted into the top port of the column 4, and horizontal extensions 1802 integrally formed on both sides of the upper part of the insertion post 1801. The top of the insertion post 1801 is hemispherical. Inside the insertion post 1801, from top to bottom, there are a smooth hole section 23 and an inner expansion hole section 22 coaxially connected. The inner wall of the smooth hole section 23 is smooth and dynamically seals with the piston column 20. The diameter of the inner expansion hole section 22 is larger than that of the smooth hole section 23. Under normal conditions, the piston column 20 is located at the bottom end of the inner expansion hole section 22. When the piston column 20 moves, the elastic rubber 25 does not change significantly. However, when the piston column 20 is inserted into the smooth hole section 23, the air inside the smooth hole section 23 is squeezed, which can quickly push the elastic rubber 25 to expand and deform. During manufacturing, the larger and longer the smooth hole section 23 is, the greater the stroke of the piston column 20, and the more obvious the inflation and expansion effect on the elastic rubber 25. The inner expansion section 22 and the smooth section 23 can be sealed with air, or the inner expansion section can have several vent holes (not shown in the figure) on its side wall to allow air to enter. The specific design can be adapted according to the size of the beat display component 2.

[0028] As one of the specific production details, such as Figure 3 , Figure 6 The top of the smooth perforated section 23 is connected to the center of the horizontal tube 24 horizontally installed in the two horizontal extensions 1802. Each end of the horizontal tube 24 passes through a sealing plate, thus entering the enclosed space formed by the elastic rubber 25 and the sealing plate. This allows air to be injected into the two enclosed spaces through the horizontal tube 24, causing the corresponding elastic rubber 25 to expand and expose the ends of the horizontal extensions, creating a rhythmic visual effect. In the production of red silk, the ends of the horizontal extensions can be made into a tapered structure, and as... Figure 7 The inner wall of the port of the horizontal extension section has an annular stop portion 180201. Correspondingly, the sealing plate is disc-shaped with threads machined on the outer cylindrical surface to allow for coaxial threaded installation within the horizontal extension section. This firmly presses the edge of the elastic rubber 25 against the inner wall of the stop portion 180201, achieving both fixation and detachable installation of the elastic rubber 25, facilitating replacement. Simultaneously, it forms the aforementioned enclosed space, resulting in a compact structure that is easy to manufacture. When the elastic rubber 25 expands, it can deform into a gourd shape to highlight the visual effect of the beat. In practice, the magnetic control of the electromagnet 10 can be based on existing technology. For example, it may also include a current controller that adjusts the current of the electromagnet 10 to achieve adjustment of the three levels of magnetic force. As for the first and second press-activated sound devices 15, both can be airbags with whistles, and the two airbags produce different sounds. The airbags with whistles can be designed with reference to children's squeaky shoes.

[0029] In the above embodiments, in order to more fully demonstrate the changes in rhythm in the form of coordinated actions of corresponding components, the following design is particularly recommended: connect the inner wall of several coils of the pressure-resistant coil spring 17, preferably one coil, to the outer wall of the bottom end of the plug post 1801 to avoid affecting the normal extension and contraction of the spring. The purpose of this design is to allow the cross portion 18 to slide out of the column 4 as the pressure-resistant coil spring 17 contracts. That is, when the sliding body 5 moves upward, the pressure-resistant coil spring 17 is compressed upward, which will move the plug post 1801 upward, that is, move the cross portion 18 axially towards the outer side of the top of the column 4. Then, the visual effect of the cross portion 18 sliding at the top of the column 4 can be seen for the corresponding rhythm, so that the rhythm can be experienced not only by sound, but also by the corresponding visual changes.

[0030] In the above description of the present invention, it should be noted that the terms "one side," "the other side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is conventionally placed during use. These terms are used only for the convenience of describing the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0031] Furthermore, terms such as "identical" do not imply that components must be absolutely identical; minor differences are permissible. The term "perpendicular" simply means that the positional relationship between components is more perpendicular than "parallel," not that the structure must be perfectly perpendicular; a slight tilt is acceptable.

[0032] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A music teaching early education rhythm instrument, comprising a rhythm instrument body (1), characterized in that: Beat display component (2) is respectively fixed on both sides of metronome body (1), the beat display component (2) includes hollow column (4), and hollow column (4) is provided with sliding body (5), electromagnet (10) from top to bottom, sliding body (5) is vertically slidably installed in vertical strip slot (401) on the inner wall of column (4) by the guide block (7) on both sides, and the upper part in vertical strip slot (401) is connected with first press sounder (15) by suspending round spring (16), and the inside of sliding body (5) is provided with magnet (6), and the lower part of support ring (8) is fixed with the electromagnet (10) by a pair of threaded rings (9), and the lower end of the lower part of support ring (8) is connected with second press sounder (15);Sliding body (5) top end is in contact with the inner wall of the top end of column (4) by pressure-resistant round spring (17), so that sliding body (5) is normally located at the upper end of support ring (8);Sliding body (5) upper end is coaxially fixed with piston rod (19), lower end is coaxially fixed with connecting rod (11), and the bottom end of connecting rod (11) is connected with limit plate; The top end of the column (4) is axially inserted into the cross section (18), and the two ends of the cross section (18) are respectively provided with an elastic rubber (25) which can expand and deform outwardly;The electromagnet (10) can have three grades of magnetic force after being energized, when the low-grade magnetic force, the sliding body (5) can be pushed up to the position where the limit plate and the second press sounder (15) are in extrusion contact, so that the second press sounder (15) sounds;When the medium-grade magnetic force, the sliding body (5) can also be pushed up to the position where the guide block (7) and the first press sounder (15) are in extrusion contact, so that the first press sounder (15) and the second press sounder (15) both sound;When the high-grade magnetic force, the sliding body (5) can also be pushed up to the position where the suspending round spring (16) is compressed, so that the piston rod (19) can push the airflow in the cross section (18) to extrude the elastic rubber (25) when it moves up, so that the elastic rubber (25) bulges outward.

2. The early education and early childhood education metronome for music teaching according to claim 1, characterized in that: The connecting rod (11) is axially slidably inserted into a seat tube (21), the bottom end of the seat tube (21) is fixed in the center of the limit disc (12), the top end is slidably inserted into the bottom end of the connecting rod (11), and the insertion end of the connecting rod (11) has a guide circular table (14), the guide circular table (14) is axially slidably installed in the seat tube (21), the guide circular table (14) and the inner wall of the top end of the seat tube (21) are in contact through the pressure spring (13), and the connecting rod (11) and the seat tube (21) move axially synchronously when the electromagnet (10) is in low-grade magnetic force, while the connecting rod (11) can slide upward relative to the seat tube (21) when it is in medium-grade magnetic force, and the pressure spring (13) is still in a state of being able to continue to compress before the piston rod (20) moves up to the limit in the cross section (18).

3. The early education and early childhood education rhythm instrument for music teaching according to claim 1, characterized in that: The cross part (18) comprises a plug-in column (1801) axially plugged into the top end of the column (4), and a horizontal extension (1802) integrally arranged on both sides of the upper part of the plug-in column (1801), and the top end of the plug-in column (1801) is hemispherical; the plug-in column (1801) is sequentially provided with a smooth hole section (23) and an inner expansion hole section (22) coaxially connected from top to bottom, the diameter of the inner expansion hole section (22) is larger than that of the smooth hole section (23), and normally, the piston column (20) is located at the bottom end of the inner expansion hole section (22), when the piston column (20) is inserted into the smooth hole section (23), the air in the smooth hole section (23) is extruded to push the elastic rubber (25) to expand and deform.

4. The early education rhythm instrument for music teaching according to claim 3, characterized in that: The side wall of the inner expansion section has a plurality of air holes.

5. The early education and early childhood education metronome for music teaching according to claim 3, characterized in that: The top end of the smooth hole section (23) is in communication with the center of the transverse pipe (24) horizontally mounted in the two horizontal extensions (1802), and the two ports of the transverse pipe (24) respectively pass through a sealing plate to enter the closed space surrounded by the elastic rubber (25) and the sealing plate.

6. The early education rhythm instrument for music teaching according to claim 5, characterized in that: The end of the horizontal extension section is a tapered structure, and the inner wall of the port of the horizontal extension section has an annular stop portion (180201); the sealing plate is a disc, and is coaxially and threadedly fitted in the horizontal extension section, and the edge of the elastic rubber (25) is tightly pressed on the inner wall of the stop portion (180201).

7. The early education and early childhood education metronome for music teaching according to claim 3, characterized in that: The elastic rubber (25) expands and deforms into a gourd shape; a bottom plate (3) is fixed on each side of the metronome body (1), and the upper surface of the center of the bottom plate (3) is fixed with the column (4).

8. The early education and early childhood education metronome for music teaching according to claim 1, characterized in that: Further comprising a current controller, which can adjust the current of the electromagnet (10) to realize the adjustment of the three-grade magnetic force.

9. The educational music teaching and preschool beat-booster according to claim 1, characterized in that: The first pressing sound generator (15) and the second pressing sound generator (15) are both air bags with whistles, and the whistles of the two air bags sound differently.

10. The early education and early childhood education metronome for music teaching according to claim 3, characterized in that: The inner wall of a plurality of turns of the pressure-resistant circular spring (17) is connected with the outer wall of the bottom end of the plug-in column (1801), so that the cross part (18) slides out of the column (4) along with the contraction of the pressure-resistant circular spring (17).

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