Expansion three-in-one connector and connection assembly

Abstract

The utility model discloses an expandable three-in-one connecting piece and connecting assembly, which comprises an expansion pipe, a screw rod, an eccentric nut and a decorative cover. The expansion pipe comprises a front pipe section, a middle pipe section and a rear pipe section. The front pipe section comprises a coaxially connected front pipe limiting section and a front pipe connecting section. The outer wall of the front pipe limiting section is surrounded by a first front pipe flange area and a second front pipe flange area, and is provided with an upper limiting notch and a lower limiting notch. The outer wall of the middle pipe section is surrounded by a middle pipe section inverted tooth. A middle pipe section deformation groove is arranged between adjacent middle pipe section inverted teeth, and a claw piece is arranged between the two adjacent middle pipe section deformation grooves. The rear pipe section is provided with a first blind hole in the shape of a half-ellipse and a second blind hole in the shape of a half-circle on the side close to the middle pipe section. The first blind hole and the second blind hole are provided with an arc-shaped rib. The eccentric nut comprises an eccentric half-circle section and an eccentric half-ellipse section. The eccentric half-circle section is provided with an anti-slip pattern on the side away from the eccentric half-ellipse section. The utility model has low precision requirements for the connecting hole, is not easily affected by misalignment and is invisible during installation.

Description

Technical Field

[0001] This utility model relates to the field of furniture connection technology, and more specifically, to an expansion-type three-in-one connector and a connection assembly. Background Technology

[0002] Invisible connectors are used to achieve a completely hidden connection between two plates or metal components, with no nails, holes, or welds on the surface, improving visual integrity and a high-end feel. While new-generation fully invisible connectors such as Lamino, OVVO, A-rings, and spring clips are rapidly penetrating the high-end customization market; Lamino is a classic invisible connector brand originating from Europe, which later became the generic name for this type of connector; OVVO focuses on hole-free connections and quick assembly / disassembly, and is an upgraded version of Lamino; A-rings are simple snap-fit ​​connectors, named for their A-shaped shape, belonging to a non-invisible but low-profile connection method. However, traditional "three-in-one / two-in-one" connectors still dominate. "Three-in-one" connectors include an eccentric wheel (eccentric head or eccentric knob), a connecting screw, and a pre-embedded nut (plastic or metal). "Three-in-one" connectors are generally only used for boards with a thickness of ≥12mm. They have good load-bearing capacity, as well as excellent locking and tensile strength. They are commonly used for cabinet side panels, shelves, and partitions. Common defects include edge cracking, making them unsuitable for thin boards. The most obvious defect is that the large hole diameter results in a large decorative cover, affecting the appearance.

[0003] Prior art 1 (application number: 2022220242836, application date: 2022.08.02) discloses a connecting component and a connecting system. The connecting component includes a reinforcing member 1', an eccentric wheel 2', and a plug 3'. The reinforcing member 1' has a connecting end and a mounting end opposite to each other. A connecting channel is formed at the end of the connecting end. At least one deformation gap 14' is formed on the side wall of the connecting end. At least one elastic part is defined by the deformation gap 14' on a portion of the connecting end. A fastening protrusion 151' is formed on the outer side wall of the elastic part. An mounting space communicating with the connecting channel is formed on the outer side wall of the reinforcing member 1'. The eccentric wheel 2' is rotatably mounted in the mounting space. The plug 3' has a insertion channel extending through both ends of the plug 3'. One end of the plug 3' is inserted into the connecting channel from the connecting end. The plug 3' can switch between a loose position and a locked position. The above-mentioned solutions have insufficient concealment of the assembly gaps or protruding structures of multiple components, which affects the aesthetics; in addition, the installation space and the corresponding accuracy of the connection holes are required to be high, and misalignment can easily affect operation; furthermore, the openings of the plates can only be reduced to 10mm, which is not suitable for thinner plates.

[0004] Prior art 2 (application number: 2022210844478, application date: 2022.05.08) discloses an eccentric wheel and a connecting assembly for connecting a first component and a second component. The eccentric wheel includes a body, an eccentric groove at the bottom of the body, an operating hole at the top of the body, an insertion port communicating with the eccentric groove on the circumferential side of the body, and a connecting port communicating with the eccentric groove and extending circumferentially along the body on the circumferential side of the body. One end of the connecting port is connected to one side of the insertion port. The minimum distance L between the top of the insertion port and the connecting port is ≤1.5mm. According to this embodiment, the eccentric wheel ensures that the neck corresponding to the connecting groove of the connecting rod aligns with the connecting port by designing the minimum distance between the top of the insertion port and the connecting port. This provides positioning for the connecting rod during assembly to the eccentric wheel, avoiding the cumbersome method of positioning the eccentric wheel through holes in the plate as in the prior art, and reducing the difficulty of drilling. The above solution has strict requirements for the dimensional accuracy of L (1.0mm≤L≤1.5mm). Machining errors can easily lead to misalignment between the neck of the connecting rod and the connecting port, affecting assembly efficiency. The design with an outer diameter of 7 to 12mm still has insufficient installation space for extremely thin plates (thickness less than 10mm), and its versatility does not fully cover all scenarios.

[0005] Prior art 3 (application number: 2022114696484, application date: 2022.11.23) discloses a connector, a connecting assembly, and a connecting system. The connector is made of plastic. The connector includes a connector body, with a connecting channel extending axially along one end of the connector body. At least one fastening barb is formed on each of the left and right outer sides of the connector body. A preset plane and a guide surface are formed between the end of the fastening barb facing away from the connector body and the outer side wall of the connector body. The preset plane and the guide surface are sequentially arranged along the direction from one end of the connector body with the opening of the connecting channel to the other end. The connector in the above solution is made of plastic, which is prone to wear and breakage when subjected to large loads for a long time. Its reliability is lower than that of metal parts, and its applicable scenarios are limited. The depth and width of the avoidance recess are easily designed improperly (such as the depth being too shallow or the width not matching the plate mounting groove), which may lead to loosening with the plate and affect the connection stability.

[0006] Therefore, providing an expansion-type three-in-one connector suitable for ultra-thin plates, with low requirements for the correspondence between the installation space and the connection holes, and not easily affected by misalignment, while also being concealed and aesthetically pleasing, is a technical problem that urgently needs to be solved in this field. Utility Model Content

[0007] In view of this, the present invention provides an expansion-type three-in-one connector to solve the problems of high precision requirements for the connecting holes, easy misalignment, and lack of concealment during installation.

[0008] This application provides an expansion-type three-in-one connector, comprising: an expansion tube, a screw, and an eccentric knob, wherein,

[0009] The expansion tube includes a cylindrical section, a middle section, and a rear section connected sequentially along its length. Each of the three sections has a screw cavity at a position corresponding to its central axis. The screw cavities of the three sections are located on the same horizontal line.

[0010] The front section of the tube includes a cylindrical front limiting section and a cylindrical front connecting section integrally connected to the front limiting section. The front connecting section is located on the side of the front limiting section near the middle section of the tube, and the side of the front connecting section away from the front limiting section is integrally connected to the side of the middle section near the front section of the tube. The front limiting section extends in the direction from the front section to the rear section of the tube. The front limiting section and the front connecting section are integrally coaxially connected. The outer wall of the side of the front limiting section away from the front connecting section is surrounded by an arc-shaped first front flange area and a second front flange area. The first front flange area and the second front flange area are distributed on opposite sides of the screw cavity.

[0011] The front limiting section of the pipe has L-shaped upper limiting notches and lower limiting notches respectively opened on the opposite sides of the screw cavity. In the direction from the front section of the pipe to the rear section of the pipe, the orthographic projections of the upper limiting notches and lower limiting notches do not overlap with the orthographic projections of the first pipe front flange area and the second pipe front flange area.

[0012] The outer wall of the middle section of the pipe is surrounded by at least three levels of arc-shaped inverted teeth. The at least three levels of inverted teeth are arranged in the direction from the front section to the rear section of the pipe and in the circumferential direction of the middle section. The tooth height of each inverted tooth increases progressively. The cross-sectional shape of the inverted tooth perpendicular to its length extension direction is a first isosceles triangle. At least two deformation grooves are provided on the middle section between adjacent inverted teeth. The at least two deformation grooves are arranged in the circumferential direction of the middle section and extend in the direction from the front section to the rear section of the pipe. The deformation grooves are connected to the screw cavity of the middle section. At least two claw plates are provided on the middle section between two adjacent deformation grooves.

[0013] Along the direction from the upper notch to the lower notch, a semi-elliptical first blind hole and a semi-circular second blind hole are provided on the rear section of the pipe near the middle section. Part of the first blind hole penetrates the rear section of the pipe along the direction from the upper notch to the lower notch, while another part of the first blind hole is recessed along the direction from the upper notch to the lower notch, and the first blind hole is connected to the screw cavity of the rear section of the pipe. Similarly, part of the second blind hole penetrates the rear section of the pipe along the direction from the upper notch to the lower notch, while another part of the second blind hole is recessed along the direction from the upper notch to the lower notch, and the second blind hole is connected to the screw cavity of the rear section of the pipe. The first blind hole and the second blind hole are connected along the direction from the front section of the pipe to the rear section of the pipe. The first blind hole is located on the side of the second blind hole near the middle section of the pipe, and the openings of the first blind hole and the second blind hole are opposite each other.

[0014] A portion of the first blind hole and a portion of the second blind hole are provided with an arc-shaped rib extending in the direction from the front section of the pipe to the rear section of the pipe, and the arc-shaped rib protrudes in the direction of the central axis of the rear section of the pipe; an expansion port communicating with the second blind hole is opened on the side of the rear section of the pipe away from the middle section of the pipe, and the expansion port penetrates the rear section of the pipe in the direction from the upper notch of the limiting position to the lower notch of the limiting position.

[0015] Along the direction from the front section of the pipe to the rear section of the pipe, the screw includes an external threaded section, a limiting flange, a smooth section and a locking end connected in sequence. The limiting flange abuts against the first pipe front flange area and the second pipe front flange area. The smooth section is located in the pipe front limiting section, the pipe front connecting section, the pipe middle section and part of the pipe rear section. The locking end is located in the pipe rear section. The smooth section is spindle-shaped.

[0016] Along the circumferential direction of the second blind hole, the eccentric button includes an eccentric semicircular portion that matches the second blind hole and an eccentric semielliptical portion that is integrally connected with the eccentric semicircular portion. The eccentric semielliptical portion matches the first blind hole, and the eccentric semicircular portion and the eccentric semielliptical portion are respectively placed in the second blind hole and the first blind hole.

[0017] The minor radius of the eccentric semi-elliptical portion is smaller than the radius of the eccentric semicircular portion. At least two triangular prism-shaped anti-slip patterns are provided on the side of the eccentric semicircular portion away from the eccentric semi-elliptical portion. The at least two anti-slip patterns extend along the length direction of the first blind hole and are arranged along the circumferential direction of the second blind hole. An eccentric groove is provided at the top of the eccentric semicircular portion and the eccentric semi-elliptical portion, which is recessed towards its bottom.

[0018] Compared with the prior art, the expansion-type three-in-one connector provided by this utility model achieves at least the following beneficial effects:

[0019] First, the expansion-type three-in-one connector provided by this utility model can reduce the accuracy of hole positions during concealed installation and reduce the impact of misaligned installation. The eccentric knob provided by this utility model has an asymmetrical structure of an eccentric semi-elliptical portion and an eccentric semi-circular portion. The purpose of reducing the circular portion is to increase the eccentric distance when the eccentric knob is screwed on. Combined with the increase in the first and second blind holes, it forms an approximately elliptical surface, allowing the eccentric knob to be installed and used normally within the conventional allowable error range. Therefore, the eccentric knob with the eccentric semi-elliptical portion has a wider range of application scenarios.

[0020] Secondly, the expansion-type three-in-one connector provided by this utility model can also improve the stability of the connection. First, the semi-circular surface of the eccentric knob provided by this utility model can be interference-fitted with the semi-elliptical surfaces of the first and second blind holes during the torsion process, increasing the connection stability of the eccentric knob; furthermore, the eccentric knob is provided with anti-slip texture, which can prevent the eccentric knob from loosening; in addition, progressively expanding tube-section counter-tooth and claw plates are provided on the outside of the expansion tube, enhancing the connection stability between the expansion tube and the connecting plate; in addition, the deformation groove in the tube-section determines the maximum opening amount of the claw plates and the expansion stroke of the claw plates, while uniformly distributing the stress during the expansion of the expansion tube to each claw plate to reduce the risk of bursting; thus, the connection stability between the expansion tube and the connecting plate can be improved.

[0021] Of course, any product implementing this utility model does not necessarily need to achieve all the technical effects described above at the same time.

[0022] Other features and advantages of the present invention will become clear from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. Attached Figure Description

[0023] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present invention and, together with their description, serve to explain the principles of the present invention.

[0024] Figure 1 This is a schematic diagram of the first structure of the connection component provided by prior art 1;

[0025] Figure 2 This is a southeast isometric view of the expansion-type three-in-one connector provided by this utility model;

[0026] Figure 3 This is a top view of the expansion-type three-in-one connector provided by this utility model;

[0027] Figure 4 This is a schematic diagram of the expansion tube structure provided by this utility model;

[0028] Figure 5 This utility model provides Figure 3 Sectional view A-A' in the middle;

[0029] Figure 6 This is a partial structural diagram of the rear section of the pipe provided by this utility model;

[0030] Figure 7 This is a schematic diagram of the screw structure provided by this utility model;

[0031] Figure 8 This is a schematic diagram of the eccentric knob provided by this utility model;

[0032] Figure 9 This is a top view of the eccentric knob provided by this utility model;

[0033] Figure 10 This is a schematic diagram of the assembly structure of the locking end and the rear section of the tube provided by this utility model;

[0034] Figure 11 This is a cross-sectional view showing the installation variations of the eccentric knob provided by this utility model;

[0035] Figure 12 This is a partial structural schematic diagram of the expansion tube provided by this utility model;

[0036] Figure 13 This is an installation diagram of the expansion tube, eccentric knob, and connecting plate provided by this utility model;

[0037] Figure 14 This is a cross-sectional view of the connection between the expansion tube and the connecting plate provided by this utility model;

[0038] Figure 15 This is a cross-sectional view of the connection between the expansion tube, the eccentric knob, and the connecting plate provided by this utility model;

[0039] Figure 16 This is a side view of the decorative cover provided by this utility model;

[0040] Figure 17 This is a diagram showing the installation variations of the decorative cover provided by this utility model. Detailed Implementation

[0041] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present invention.

[0042] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0043] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0044] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0045] 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 discussed further in subsequent figures.

[0046] Example 1

[0047] Reference Figures 2 to 15 As shown, Figure 2 This is a southeast isometric view of the expansion-type three-in-one connector provided by this utility model; Figure 3 This is a top view of the expansion-type three-in-one connector provided by this utility model;

[0048] Figure 4 This is a schematic diagram of the expansion tube structure provided by this utility model; Figure 5 This utility model provides Figure 3 Sectional view A-A' in the middle; Figure 6 This is a partial structural diagram of the rear section of the pipe provided by this utility model; Figure 7 This is a schematic diagram of the screw structure provided by this utility model; Figure 8 This is a schematic diagram of the eccentric knob provided by this utility model; Figure 9 This is a top view of the eccentric knob provided by this utility model; Figure 10 This is a schematic diagram of the assembly structure of the locking end and the rear section of the tube provided by this utility model; Figure 11 This is a cross-sectional view showing the installation variations of the eccentric knob provided by this utility model; Figure 12 This is a partial structural schematic diagram of the expansion tube provided by this utility model; Figure 13 This is an installation diagram of the expansion tube, eccentric knob, and connecting plate provided by this utility model; Figure 14 This is a cross-sectional view of the connection between the expansion tube and the connecting plate provided by this utility model; Figure 15 This is a cross-sectional view showing the connection of the expansion tube, eccentric knob, and connecting plate provided by this utility model. This embodiment provides an expansion-type three-in-one connector, including an expansion tube 1, a screw 2, and an eccentric knob 3, wherein...

[0049] The expansion tube 1 includes a cylindrical front section 11, a middle section 12, and a rear section 13 connected sequentially along its length. Each of the three sections has a screw cavity 10 at a position corresponding to its central axis. The screw cavities 10 of the front section 11, the middle section 12, and the rear section 13 are located on the same horizontal line.

[0050] The front section 11 includes a front limiting section 11L and a cylindrical front connecting section 11U integrally connected to the front limiting section 11L. The front connecting section 11U is located on the side of the front limiting section 11L near the middle section 12, and the side of the front connecting section 11U away from the front limiting section 11L is integrally connected to the side of the middle section 12 near the front section 11. The front limiting section 11L extends along the front section 11 towards the rear section 13. The front limiting section 11L and the front connecting section 11U are integrally coaxially connected. The outer wall of the side of the front limiting section 11L away from the front connecting section 11U is surrounded by an arc-shaped first front flange area 11R and a second front flange area 11E. The first front flange area 11R and the second front flange area 11E are distributed on opposite sides of the screw cavity 10.

[0051] The pipe front limiting section 11L has L-shaped upper limiting notch 111 and lower limiting notch 112 respectively opened on the opposite sides of the screw cavity 10. In the direction from the pipe front section 11 to the pipe rear section 13, the orthographic projection of the upper limiting notch 111 and the lower limiting notch 112 does not overlap with the orthographic projection of the first pipe front flange area 11R and the second pipe front flange area 11E.

[0052] The outer wall of the pipe section 12 is surrounded by at least three levels of arc-shaped pipe section inverted teeth 121. The at least three levels of pipe section inverted teeth 121 are arranged in the direction from the front section 11 to the rear section 13 and in the circumferential direction of the pipe section 12. The tooth height of each pipe section inverted tooth 121 increases progressively. The cross-sectional shape of the pipe section inverted tooth 121 perpendicular to its length extension direction is a first isosceles triangle. At least two pipe section deformation grooves 122 are opened on the pipe section 12 between adjacent pipe section inverted teeth 121. The at least two pipe section deformation grooves 122 are arranged in the circumferential direction of the pipe section 12 and extend in the direction from the front section 11 to the rear section 13. The pipe section deformation grooves 122 are connected to the screw cavity 10 of the pipe section 12. At least two claw plates 123 are provided on the pipe section 12 between two adjacent pipe section deformation grooves 122.

[0053] Along the direction from the upper limiting notch 111 to the lower limiting notch 112, a semi-elliptical first blind hole 131F and a semi-circular second blind hole 131S are provided on the side of the rear section 13 near the middle section 12. Part of the first blind hole 131F penetrates the rear section 13 along the direction from the upper limiting notch 111 to the lower limiting notch 112, while another part of the first blind hole 131F is recessed along the direction from the upper limiting notch 111 to the lower limiting notch 112, and the first blind hole 131F communicates with the screw cavity 10 of the rear section 13; a part of the second blind hole 131S is recessed along the direction from the upper limiting notch 111 to the lower limiting notch 112. The upper notch 111 extends through the rear section 13 of the tube in the direction of the lower notch 112. The other part of the second blind hole 131S is recessed in the direction of the upper notch 111 extending to the lower notch 112, and the second blind hole 131S is connected to the screw cavity 10 of the rear section 13 of the tube. The first blind hole 131F and the second blind hole 131S are connected in the direction of the front section 11 extending to the rear section 13 of the tube. The first blind hole 131F is located on the side of the second blind hole 131S near the middle section 12 of the tube, and the opening part of the first blind hole 131F and the opening part of the second blind hole 131S are opposite to each other.

[0054] A portion of the first blind hole 131F and a portion of the second blind hole 131S are provided with an arc-shaped rib 134 extending in the direction from the front section 11 to the rear section 13 of the pipe. The arc-shaped rib 134 protrudes in the direction of the central axis of the rear section 13 of the pipe. An expansion port 132 communicating with the second blind hole 131S is opened on the side of the rear section 13 away from the middle section 12 of the pipe. The expansion port 132 penetrates the rear section 13 of the pipe in the direction from the upper limiting notch 111 to the lower limiting notch 112.

[0055] Along the direction from the front section 11 to the rear section 13, the screw 2 includes an external thread section 21, a limiting flange 22, a smooth section 23 and a locking end 24 connected in sequence. The limiting flange 22 abuts against the first front flange area 11R and the second front flange area 11E. The smooth section 23 is located in the front limiting section 11L, the front connecting section 11U, the middle section 12 and part of the rear section 13. The locking end 24 is located in the rear section 13. The smooth section 23 is spindle-shaped.

[0056] Along the circumferential direction of the second blind hole 131S, the eccentric button 3 includes an eccentric semicircular portion 3C that matches the second blind hole 131S and an eccentric semielliptical portion 3E that is integrally connected to the eccentric semicircular portion 3C. The eccentric semielliptical portion 3E matches the first blind hole 131F. The eccentric semicircular portion 3C and the eccentric semielliptical portion 3E are respectively placed in the second blind hole 131S and the first blind hole 131F.

[0057] The minor radius of the eccentric semi-elliptical portion 3E is smaller than the radius of the eccentric semi-circular portion 3C. At least two anti-slip patterns 33 are provided on the side of the eccentric semi-circular portion 3C away from the eccentric semi-elliptical portion 3E. The at least two anti-slip patterns 33 extend along the length direction of the first blind hole 131F and are arranged along the circumferential direction of the second blind hole 131S. An eccentric groove 31 is provided at the top of the eccentric semi-circular portion 3C and the eccentric semi-elliptical portion 3E, which is recessed towards its bottom.

[0058] Specifically, continue to refer to Figure 2 and Figure 4 As shown, this embodiment provides an expansion-type three-in-one connector, which includes an expansion tube 1, a screw 2, and an eccentric knob 3. The screw 2 is sleeved in the screw cavity 10 of the expansion tube 1 along the direction from the front section 11 to the rear section 13 of the tube. The eccentric knob 3 is engaged with the screw 2 inside the expansion tube 1 along the through direction of the first blind hole 131F.

[0059] The expansion tube 1 is a cylinder of varying thickness, with a screw cavity 10 formed along its length. The screw cavity 10 is a cylinder mathematically similar to the expansion tube 1, and its shape matches the outer wall of the screw 2. The diameter of the screw cavity 10 is no greater than the outer diameter of the expansion tube 1; along the direction from the front section 11 to the rear section 13, the length of the screw cavity 10 is less than the length of the expansion tube 1. The expansion tube 1 includes a front section 11, a middle section 12, and a rear section 13 along its length, all integrally formed and located on the same horizontal line. The side of the screw cavity 10 closest to the front section 11 and the side of the front section 11 furthest from the rear section 13 are on the same horizontal vertical plane. The rear section 13 of the tube is used to fix the eccentric knob 3, and the front section 11 of the tube is used for positioning in the horizontal direction with the surface of the connecting plate 100 during installation, ensuring that the eccentric groove 31 of the eccentric knob 3 and the hole 011 of the connecting plate 100 are aligned (see reference). Figure 14 and Figure 15 Correspondingly, the front section 11 and the middle section 12 of the tube are used together to thread the screw 2. The plate hole 011 of the connecting plate 100 is the connecting hole on one side of the plane of the connecting plate 100.

[0060] The front section 11 is cylindrical, and any cross-sectional shape of the front section 11 along its axial direction is T-shaped. The front section 11 includes a front limiting section 11L and a front connecting section 11U coaxially integrated with the front limiting section 11L. The front limiting section 11L and the front connecting section 11U are coaxially connected but are cylinders with the same radius. The radii of the front connecting section 11U and the front limiting section 11L are the same as the radius of the middle section 12. The end hole 012 is the connecting hole on one side of the connecting plate 100 in the thickness direction. The opening direction of the plate hole 011 and the opening direction of the end hole 012 are perpendicular to each other. The side of the front connecting section 11U away from the front limiting section 11L is coaxially connected to the middle section 12. The front limiting section 11L is used to limit the plugging of the expansion tube 1 in the end hole 012.

[0061] The outer wall of the pipe-front limiting section 11L, on the side away from the pipe-front connecting section 11U, is surrounded by an arc-shaped first pipe-front flange area 11R and a second pipe-front flange area 11E. Both the first pipe-front flange area 11R and the second pipe-front flange area 11E are formed by arc-shaped bending of rectangular sheet metal, and they have the same structure and size. The first pipe-front flange area 11R and the second pipe-front flange area 11E are distributed on opposite sides of the screw cavity 10; the arc-shaped bending direction of the first pipe-front flange area 11R and the second pipe-front flange area 11E is the central axis of the pipe-front section 11. The sum of the thicknesses of the first pipe-front flange area 11R and the second pipe-front flange area 11E along the radial direction of the pipe-front section 11, and the sum of the outer diameters of the pipe-front connecting section 11U, are equal to the diameter of the end hole 012. The hole depth of end face 012 is often subject to error. When the connecting plate 100 is medium density board, end face 012 is prone to cracking. The first tube front flange area 11R and the second tube front flange area 11E are used to support end face 012 and prevent it from cracking.

[0062] A limiting upper notch 111 and a limiting lower notch 112 are further provided on the side of the pipe-front limiting section 11L away from the pipe-front connecting section 11U. Both the limiting upper notch 111 and the limiting lower notch 112 are notches formed by subtracting two semi-circular grooves from the pipe-front limiting section 11L. Perpendicular to the connecting line direction of the limiting upper notch 111 and the limiting lower notch 112, the orthographic projections of the limiting upper notch 111 and the limiting lower notch 112 are both L-shaped, and the L-shaped orthographic projections of the limiting upper notch 111 and the limiting lower notch 112 are symmetrical about the central axis of the pipe-front limiting section 11L. The limiting upper notch 111 and the limiting lower notch 112 are used for engagement and positioning when the expansion tube 1 is installed in the end face 012. The connecting line direction of the limiting upper notch 111 and the limiting lower notch 112 is the thickness direction of the connecting plate 100. When the upper limiting notch 111 and the lower limiting notch 112 are clamped and kept parallel to the connecting plate 100 by the installation tool 03 on the outside of the connecting plate 100, the opening direction of the first blind hole 131F and the second blind hole 131S can be perpendicular to the plate surface of the connecting plate 100. This makes it convenient for the blind hole 11 and the plate hole 011 to be positioned in the circumferential direction of the expansion tube 1 when installing the expansion tube 1, thereby facilitating the screwing of the eccentric knob 3 in the plate hole 011 of the connecting plate 100.

[0063] Continue to refer to Figure 2 and Figure 4 As shown, the outer wall of the pipe section 12 is surrounded by at least three levels of arc-shaped inverted teeth 121. All three levels of inverted teeth 121 are progressively expanding structures. The progressively expanding structure of the inverted teeth 121 means that the inverted teeth 121 have multiple levels. As the height of the tooth column of the inverted teeth 121 gradually increases from the front section 11 to the rear section 13, it facilitates the gradual increase of the inverted teeth 121 from the radial direction inward, forming a reverse taper similar to a "barb." This gradual compression achieves a tighter connection between the pipe section 12 and the connecting plate 100, improving connection stability. The inverted teeth 121 are arc-shaped rings arranged along the circumference of the pipe section 12. The inner diameter of the inverted teeth 121 gradually increases, and its outer diameter is equal to the diameter of the end face hole 012. The cross-sectional shape of the inverted teeth 121 in the middle section of the tube, perpendicular to its length extension direction, is a first isosceles triangle. The inverted teeth 121 are integrally connected to the middle section 12 of the tube on one side of the base of the first isosceles triangle. The inverted teeth 121 in the middle section of the tube are provided in at least three levels along the length direction of the tube expansion 1 from the front section 11 to the rear section 13. This embodiment takes three levels as an example, and it is not intended to be a limitation on the number of inverted teeth. The inverted teeth 121 in the middle section of the tube are provided in at least three levels from the front section 11 to the rear section 13 of the tube, and the tooth height of each inverted tooth 121 increases progressively.

[0064] Optionally, the tooth height of each inverted tooth 121 in the middle section of the tube can gradually decrease or increase along the direction from the front section 11 to the rear section 13. The purpose of this is to save effort when assembling the expansion tube 1 or installing the screw 2, that is, to loosen first and then tighten or tighten first and then loosen when inserting the expansion tube 1 or the screw 2. Of course, depending on the actual situation, if the inverted tooth 121 in the middle section of the tube is made of a highly elastic plastic material, it can also be made so that the tooth height of each inverted tooth 121 in the middle section of the tube is equal along the direction from the front section 11 to the rear section 13.

[0065] Furthermore, along the circumferential direction of the pipe section 12, at least two pipe section deformation grooves 122 are formed on the pipe section 12 between adjacent pipe section countersunk teeth 121. The at least two pipe section deformation grooves 122 are arranged along the circumferential direction of the pipe section 12, and are symmetrical about the central axis of the pipe section 12. The at least two pipe section deformation grooves 122 extend from the front section 11 to the rear section 13. The pipe section deformation grooves 122 penetrate the pipe section 12 along the pipe wall thickness direction; along the circumferential direction of the pipe section 12, the width of the pipe section deformation grooves 122 is typically controlled between 1.5 and 3 mm. The pipe section deformation grooves 122 communicate with the screw cavity 10 of the pipe section 12. The tube mid-section deformation groove 122 is used to reserve sufficient deformation space for the tube mid-section 12, and to avoid stress concentration that could cause the tube wall of the tube mid-section 12 to crack. That is, after the connecting plate 100 is installed on the expansion tube 1, the two sides of the tube mid-section deformation groove 122 on the tube mid-section 12 of the expansion tube 1 are squeezed and deformed, and the diameter of the screw cavity 10 in the tube mid-section 12 of the expansion tube 1 becomes smaller. In order to prevent the expansion tube 1 from being squeezed and deformed too much, the tube mid-section deformation groove 122 plays the role of limiting the excessive deformation of the expansion tube 1 and reducing the risk of the expansion tube 1 bursting, while ensuring that the screw 2 is successfully embedded in the next step. In this embodiment, two tube deformation grooves 122 are formed on the tube section 12 between adjacent tube section countertooth 121 along the circumferential direction of the tube section 12. The two tube deformation grooves 122 are evenly distributed along the circumferential direction of the expansion tube 1 and have a gap. The two tube deformation grooves 122 are used to make the deformation of the subsequent expansion tube 1 more uniform, prevent excessive force on one side, and release the deformation stress of the expansion tube 1 when the screw 2 is screwed in. The purpose of the two tube deformation grooves 122 is to increase the flexibility or elasticity of the cooperation between the expansion tube 1 and the screw 2, reduce the difficulty of installing the screw 2, and increase the pulling force of the expansion tube 1 when it opens and bites the connecting plate 100.

[0066] At least two claw plates 123 are provided on the pipe section 12 between two adjacent pipe section deformation grooves 122; the claw plates 123 are arranged along the length extension direction of the pipe section deformation grooves 122. The claw plates 123 are used to engage with the connecting plate 100 after the expanded pipe 1 is deformed, thereby enhancing the connection stability between the expanded pipe 1 and the connecting plate 100.

[0067] Continue to refer to Figures 2 to 6As shown, the rear section 13 of the tube has a first blind hole 131F and a second blind hole 131S that match the eccentric knob 3. The opening direction of the first blind hole 131F and the second blind hole 131S is perpendicular to the central axis of the rear section 13 of the tube, and their specific penetration direction is the direction from the upper limiting notch 111 to the lower limiting notch 112. The first blind hole 131F is a semi-elliptical cylinder, that is, it is based on the semi-circle plus to become elliptical. Similarly, the eccentric button 3 is based on the semi-circle minus to become elliptical. It can be understood that: the first blind hole 131F is based on the semi-circle plus by cutting off part of the rear section 13 of the tube to form the semi-elliptical first blind hole 131F; the eccentric button 3 is based on the semi-circle minus to become the eccentric semi-elliptical part 3E that matches the semi-elliptical shape of the first blind hole 131F; the second blind hole 131S is a semi-circular cylinder; that is, along the direction from the upper limiting notch 111 to the lower limiting notch 112, the orthographic projection shape of the first blind hole 131F is semi-elliptical; the orthographic projection shape of the second blind hole 131S is semi-circular. The minor axis of the semi-ellipse of the first blind hole 131F is the same as the diameter of the semi-circle of the second blind hole 131S. The side corresponding to the minor axis of the first blind hole 131F coincides with the side corresponding to the diameter of the second blind hole 131S. Furthermore, the end of the first blind hole 131F near the limiting notch 111 and the end of the second blind hole 131S near the limiting notch 111 are on the same horizontal plane. Along the penetration direction of either the first blind hole 131F or the second blind hole 131S, the orthographic projections of the first blind hole 131F and the second blind hole 131S completely coincide within the orthographic projection of the rear section 13 of the pipe.

[0068] Along the direction from the upper limiting notch 111 to the lower limiting notch 112, the first blind hole 131F partially penetrates the rear section 13 of the tube, while the other part of the first blind hole 131F is only recessed; the recessed depth of the first blind hole 131F is greater than the depth of the eccentric knob 3 along the direction from the upper limiting notch 111 to the lower limiting notch 112. The side of the first blind hole 131F near the front section 11 of the tube is perpendicularly connected to the side of the screw cavity 10 away from the front section 11 of the tube.

[0069] Along the direction from the upper limiting notch 111 to the lower limiting notch 112, the second blind hole 131S partially penetrates the rear section 13 of the tube, while the other part of the second blind hole 131S is only recessed. The side of the second blind hole 131S near the first blind hole 131F is connected and communicates with the first blind hole 131F and the screw cavity 10. The first blind hole 131F and the second blind hole 131S communicate along the direction from the front section 11 to the rear section 13 of the tube, and the direction of penetration of the first blind hole 131F and the second blind hole 131S is the same as the direction from the front section 11 to the rear section 13 of the tube. The first blind hole 131F is located on the side of the second blind hole 131S near the middle section 12 of the tube, and the opening portion of the first blind hole 131F is opposite to the opening portion of the second blind hole 131S. After the screw 2 passes through the screw cavity 10, the end of the screw 2 away from the front section 11 of the tube can be inserted into the first blind hole 131F and the second blind hole 131S. The pre-positioning section 11L of the front section 11 can also be used to limit and fix the expansion tube 1 during installation, preventing excessive plugging that would cause the first blind hole 131F and the second blind hole 131S to misalign with the plate hole 011 in the axial direction. The rear section 13 has a locking end on one side corresponding to the semi-elliptical first blind hole 131F, and a non-locking end on one side corresponding to the semi-circular second blind hole 131S. The different positions of the locking end and the non-locking end of the rear section 13 relative to the fixed eccentric knob 3 allow for the fixation of the eccentric knob 3.

[0070] Furthermore, some of the first blind holes 131F and some of the second blind holes 131S are provided with arc-shaped ribs 134 extending in the direction from the front section 11 to the rear section 13 of the tube. The material of the arc-shaped ribs 134 is the same as that of the front section 11 of the tube, and it can be integrally cast or injection molded. The arc-shaped ribs 134 are arc-shaped protrusions, which can be crescent-shaped arc surfaces. The central axis of the arc-shaped ribs 134 along its length direction is on the same horizontal plane as the central axis of the expansion tube 1 in the direction from the front section 11 to the rear section 13 of the tube. Both ends of the arc-shaped ribs 134 along its length direction are smoothly connected to the first blind hole 131F or the second blind hole 131S. The arc-shaped concave direction of the arc-shaped ribs 134 is away from the central axis of the first blind hole 131F or the second blind hole 131S. The arc-shaped ribs 134 are used to reinforce and fix the eccentric knobs 3 in the first blind holes 131F and the second blind holes 131S. During its rotation within the first blind hole 131F and the second blind hole 131S, the eccentric knob 3 generates deformation pressure on the rear section 13 of the tube. An expansion port 132, communicating with the second blind hole 131S, is provided on the side of the rear section 13 away from the middle section 12. The expansion port 132 is used to alleviate the deformation pressure on the rear section 13. Specifically, the expansion port 132 is a through hole, its opening direction being from the upper limiting notch 111 to the lower limiting notch 112.

[0071] Optionally, the first blind hole 131F or the second blind hole 131S can also be a completely blind hole.

[0072] Continue to refer to Figures 2 to 7 As shown, the screw 2 is based on the currently widely used and mature standard screw specifications, ensuring versatility and continuity, with a spindle-shaped structure only in the middle of the shaft. Along the direction from the front section 11 to the rear section 13, the screw 2 includes a sequentially connected external thread section 21, a limiting flange 22, a smooth section 23, and a locking end 24. The limiting flange 22 abuts against the first front flanged area 11R and the second front flanged area 11E. The smooth section 23 is located in the front limiting section 11L, the front connecting section 11U, the middle section 12, and part of the rear section 13. The locking end 24 is located in the rear section 13.

[0073] The external thread section 21 is located on the side of the screw 2 near the front section 11 of the pipe. The outer wall of the external thread section 21 is a metric M6, M8, imperial, or non-standard full thread, specifically a thread angle of 60°, 55°, or a non-standard triangular thread. The starting end of the external thread section 21 near the front section 11 of the pipe has a 15° guide chamfer 133 to facilitate quick alignment with the internal thread of the mating part and avoid "jamming". A circular limiting flange 22 is provided along the circumference of the external thread section 21 near the smooth section 23. The limiting flange 22 is a radially protruding annular structure, mainly used for mating and limiting. The radius of the limiting flange 22 is larger than the radius of the screw cavity 10 near the front section 11 of the tube. When the screw 2 is screwed into the screw cavity 10 of the expansion tube 1, the end face of the limiting flange 22 will tightly abut against the limiting flange 22 of the front section 11 of the tube and the first front flange area 11R and the second front flange area 11E of the tube, precisely limiting the screw 2's screwing depth. The smooth section 23 connects the limiting flange 22 and the locking end 24. The smooth section 23 is spindle-shaped, with its shape gradually thickening from both ends to the middle and then narrowing from the middle to both ends, similar to the outline of a spindle. The diameter of the smooth section 23 is smaller at both ends near the limiting flange 22 and the locking end 24, and is thickest in the middle. The maximum diameter of the smooth section 23 is the same as the diameter of the screw cavity 10 of the expansion tube 1.

[0074] When the screw 2 is turned and pushed forward, the spindle-shaped structure slides along the screw cavity 10 of the expansion tube 1. The thickest part of the smooth section 23 evenly squeezes the middle section 12 of the tube, forcing the middle section 12 of the tube to expand outward and fit against the wall of the mounting hole. The locking end 24 is located on the side of the screw 2 near the rear section 13 of the tube. It is mushroom-shaped, and its maximum diameter is smaller than the diameter of the screw cavity 10, the first blind hole 131F, or the second blind hole 131S. When the locking end 24 is inserted into the eccentric button 3, rotating the eccentric button 3 can make the inner wall of the eccentric button 3 tightly engage with the step between the neck and head of the mushroom head, forming a mechanical lock.

[0075] Continue to refer to Figures 2 to 9As shown, the eccentric knob 3 is an uneven cylinder whose length extends in the direction of penetration of the first blind hole 131F. Along the circumferential direction of the first blind hole 131F and the second blind hole 131S, the eccentric knob 3 includes an eccentric semicircular portion 3C that matches the second blind hole 131S and an eccentric semielliptical portion 3E integrally connected to the eccentric semicircular portion 3C. The eccentric semielliptical portion 3E matches the first blind hole 131F, and the eccentric semicircular portion 3C and the eccentric semielliptical portion 3E are correspondingly positioned within the second blind hole 131S and the first blind hole 131F. The minimum absolute difference between the minor radius of the eccentric semielliptical portion 3E and the radius of the eccentric semicircular portion 3C can be 0.5 mm. Preferably, the absolute difference between the minor radius of the eccentric semielliptical portion 3E and the radius of the eccentric semicircular portion 3C can range from 0.5 to 1 mm. Along the through-hole direction of the first blind hole 131F, the orthographic projections of the eccentric semicircular portion 3C and the eccentric semielliptical portion 3E coincide with the orthographic projections of the first blind hole 131F and the second blind hole 131S. In the non-locked state of the eccentric button 3, the eccentric semicircular portion 3C is located near the rear section 13 of the tube, and the eccentric semielliptical portion 3E is located near the front section 11 of the tube.

[0076] The eccentric semi-elliptical portion 3E is formed by cutting away a complete semi-circular surface. The eccentric semi-circular portion 3C of the eccentric knob 3 is the locking end. On the side of the eccentric semi-circular portion 3C away from the eccentric semi-elliptical portion 3E, there is an anti-slip texture 33 extending along the penetrating direction of the first blind hole 131F. The anti-slip texture 33 is a triangular prism extending along the penetrating direction of the first blind hole 131F. At least two of them are arranged parallel to each other along the circumference of the semi-circle of the eccentric knob 3 on the side corresponding to the semi-circle of the eccentric knob 3. The anti-slip texture 33 is used to increase the connection stability between the eccentric wheel and the blind hole 131, and to prevent the eccentric knob 3 from rotating and reducing the tension and locking force, thus causing loosening and separation of the eccentric knob 3 from the rear section 13 of the tube.

[0077] When the eccentric semicircular part 3C coincides with the semicircular part of the second blind hole 131S, the eccentric button 3, the first blind hole 131F and the second blind hole 131S are in an unlocked state, the outer diameter of the tube mid-section reverse tooth 121 on the outer wall of the tube mid-section part 12 is the same as the diameter of the end hole 012; the arc rib 134 does not directly contact the eccentric button 3. When the eccentric button 3 rotates clockwise 180° within the first blind hole 131F and the second blind hole 131S, the eccentric semicircular portion 3C of the eccentric button 3 passes through the second blind hole 131S, through the arc-shaped rib 134, and gradually squeezes into the semi-elliptical shape of the first blind hole 131F, thus fixing the eccentric semicircular portion 3C within the first blind hole 131F. When the eccentric button rotates, the eccentric semicircular portion 3C of the eccentric button 3 squeezes the arc-shaped rib, forcing the two sides of the expansion tube to expand outwards. The reverse teeth 121 in the middle section of the tube bite into the connecting plate 100, increasing the tension and locking force to prevent separation. The eccentric semicircular portion 3C of the eccentric button 3 and the semicircular surface of the first blind hole 131F together clamp the arc-shaped rib 134, which increases the connection stability between the eccentric button 3 and the first blind hole 131F. Specifically, the eccentric button 3 achieves its clockwise locking rotation of 180° through the eccentric slot 31. An eccentric knob 3 has an eccentric slot 31 at one end along its length, which is recessed into either the first blind hole 131F or the second blind hole 131S. The orthographic projection of the eccentric slot 31 completely overlaps with the orthographic projection of the eccentric knob 3 along the through-hole direction of the first blind hole 131F. The orthographic projection shape of the eccentric slot 31 can be cross-shaped. Users can use tools such as screwdrivers to turn the eccentric knob 3 through the eccentric slot 31.

[0078] Alternatively, the eccentric slot 31 can also be an internal hexagonal slot, a square slot, or a pentagonal slot. This embodiment does not impose many limitations on its specific slot shape. This embodiment only uses a cross-shaped eccentric slot 31 as an example.

[0079] In the specific implementation process, continue to refer to Figures 2 to 15 As shown, this embodiment can be used for splicing two connecting plates 100, and its specific operation is as follows:

[0080] The first step is the assembly of the expansion tube 1 and the eccentric knob 3: The expansion tube 1 and the eccentric knob 3 are assembled into one piece by a hardware factory, so that the end of the eccentric knob 3 away from its eccentric slot 31 is inserted into the first blind hole 131F and the second blind hole 131S near the limiting notch 111 along the through direction of the first blind hole 131F; the eccentric semi-elliptical part 3E of the eccentric knob 3 matches the semi-circular part of the first blind hole 131F, and one side of the semi-circular part of the eccentric knob 3 matches the semi-circular part of the second blind hole 131S. The groove in the middle of the eccentric knob 3 fits precisely into the arc-shaped rib 134 in the eccentric knob hole of the expansion tube 1. The eccentric slot 31 has a directional mark, with the longer end of the mark pointing towards the expansion port 132 to avoid incorrect installation and also for identification during on-site installation or disassembly. The directional mark on the eccentric slot 31 is prior art in this embodiment, and will not be described in detail here.

[0081] The second step involves the installation of the eccentric knob 3, the expansion tube 1, and the connecting plate 100. The furniture factory uses a special installation tool 03 to embed the expansion tube 1, which has had the eccentric knob 3 installed in the first step, into the end face hole 012. The installation tool 03 can match the upper limiting notch 111 and the lower limiting notch 112 of the tube front section 11. The limiting plate on the installation tool 03 is level with the surface of the connecting plate 100 to ensure that the upper limiting notch 111 and the lower limiting notch 112 are level with the surface of the connecting plate 100. The first tube front flange area 11R and the second tube front flange area 11E are limited by the depth of the end face hole 012 of the connecting plate 100 to ensure accuracy. Otherwise, there will be a deviation between the eccentric groove 31 and the surface hole 011. At the same time, it is ensured that the eccentric groove 31 of the eccentric knob 3 corresponds exactly to the surface hole 011 of the board. In this way, Phillips head tools such as screwdrivers can be used to screw the eccentric knob 3 through the surface hole 011 of the board. Then the assembled eccentric knob 3, expansion tube 1 and connecting plate 100 are sent to the actual installation site.

[0082] The third step, on-site installation: The steps on-site are the same as the existing installation process, and will not be elaborated on in this embodiment. It should be noted that: when the screw 2 is acted upon by the eccentric knob 3 and moves from the front section 11 to the rear section 13 of the tube, the spindle shape of the screw 2 gradually approaches the reverse teeth 121 of the middle section of the expansion tube 1, forcing the reverse teeth 121 of the middle section of the outer wall of the expansion tube 1 to further bite into the connecting plate 100.

[0083] Compared with the prior art, the expansion-type three-in-one connector provided in this embodiment achieves at least the following beneficial effects:

[0084] First, the expansion-type three-in-one connector provided in this embodiment can reduce the hole position accuracy of concealed installation and reduce the impact of misaligned installation. The eccentric knob 3 provided in this embodiment has an asymmetrical structure of an eccentric semi-elliptical portion 3E and an eccentric semi-circular portion 3C. The purpose of reducing the circular portion 3E is to increase the eccentric distance when the eccentric knob 3 is screwed on. Combined with the increments of the first blind hole 131F and the second blind hole 131S, it forms an approximately elliptical surface, allowing the eccentric knob 3 to be installed and used normally within the allowable error range. Therefore, the eccentric knob 3 with the eccentric semi-elliptical portion 3E has a wider range of application scenarios.

[0085] Secondly, the expansion-type three-in-one connector provided in this embodiment can also improve the stability of the connection. First, the semi-circular surface of the eccentric knob 3 provided in this embodiment can be interference-fitted with the semi-elliptical surfaces of the first blind hole 131F and the second blind hole 131S during the torsion process, which increases the connection stability of the eccentric knob 3. Furthermore, the eccentric knob 3 is provided with anti-slip texture 33, which can prevent the eccentric knob 3 from loosening. In addition, a progressively expanding tube-middle section inverted tooth 121 and claw plate 123 are provided on the outside of the expansion tube 1, which enhances the connection stability between the expansion tube 1 and the connecting plate 100. In addition, the tube-middle section deformation groove 122 determines the maximum opening amount of the claw plate 123 and the expansion stroke of the claw plate 123, while uniformly distributing the stress during the expansion of the expansion tube 1 to each claw plate 123 to reduce the risk of bursting. This can improve the connection stability between the expansion tube 1 and the connecting plate 100.

[0086] In one alternative embodiment, continue to refer to Figures 2 to 12 As shown, at least two claws 123 are arranged along the direction from the front section 11 of the tube to the rear section 13 of the tube and along the circumferential direction of the second blind hole 131S. Each claw 123 is close to the side of the deformation groove 122 in the middle section of the tube. The cross-sectional shape of the claw 123 is triangular along the direction from the upper limiting notch 111 to the lower limiting notch 112. The cross-sectional shape of the claw 123 is trapezoidal along the direction from the middle section 12 of the tube to the screw cavity 10 in the middle section 12 of the tube.

[0087] Specifically, triangular prism claws 123 are formed on the outer wall of the pipe section 12 along the length of the pipe section deformation groove 122. The claws 123 are integrally formed with the pipe section 12 and are triangular prism structures that protrude outward along the outer side of the pipe wall of the pipe section 12. The thickness of the claws 123 gradually decreases from the bottom edge to the top corner, which ensures structural strength and gives the tip a certain sharpness. In addition, it also avoids cracking of the connecting plate 100, especially since medium-density fiberboard is prone to cracking. The position of each claw 123 corresponds to the edge of the pipe section deformation groove 122, so that the claws 123 become extensions of the pipe walls on both sides of the pipe section deformation groove 122. When the screw 2 enters from the front section 11 of the expansion tube 1, the claw 123 and the deformation groove 122 in the middle section of the tube are forced to flip and open along the horizontal direction of the plate surface of the connecting plate 100 as the tube wall of the expansion tube 1 deforms. The apex of the claw 123 will gradually move away from the central axis of the expansion tube 1 and produce a radial interference fit with the hole wall.

[0088] Through the above scheme, the claw plate 123 forms a radial interference fit with the inner wall of the connecting plate 100: the apex and side of the claw plate 123 press tightly against the hole wall of the end face hole 012. For wood or fiber connecting boards, the acute angle of the claw plate 123 will slightly embed into the fiber structure of the connecting plate 100, forming a mechanical interlock; for plastic or metal substrates, the claw plate 123 generates huge friction with the hole wall through elastic pressure. This fit can not only counteract the axial tension of the screw 2, but also restrict the circumferential rotation of the expansion tube 1 in the hole, ultimately achieving a firm connection between the tube section 12 and the substrate. When disassembly is required, the screw 2 is unscrewed in the reverse direction, and the tube section 12 contracts under its own elasticity, the claw plate 123 returns to the wall-adhering state, and can be easily removed from the hole, avoiding irreversible damage to the substrate.

[0089] In one alternative embodiment, the trapezoidal cross-sectional area of ​​the claw 123 is smaller than the cross-sectional area of ​​the first isosceles triangle of the inverted tooth 121 in the middle section of the tube.

[0090] Specifically, due to different force requirements, the inverted tooth 121 in the middle section of the pipe, as the active force transmission component, needs to bear the load at the driving end and convert it into radial force; its large cross-sectional area can reduce stress concentration. The claw 123, as the driven component, is only subjected to radial reaction force; its trapezoidal structure, through uniform stress distribution, allows for strength requirements to be met with a small cross-section. Furthermore, due to differences in space constraints, the claw 123 needs radial expansion and contraction; its small cross-sectional area reduces space occupation and adapts to different pipe diameters. The inverted tooth 121 in the middle section of the pipe is located on the central axis, with axial movement as the primary motion; ample radial space allows for a larger cross-section. Moreover, according to functional adaptation needs, the trapezoidal surface of the claw 123 cooperates with the inverted tooth 121 in the middle section of the pipe to achieve efficient force conversion; the small cross-section reduces weight and improves response speed; the large cross-section of the inverted tooth 121 in the middle section of the pipe ensures tooth surface strength and reduces wear and cracking.

[0091] With the above scheme, when the screw 2 is screwed into the expansion tube 1 and the expansion tube 1 expands and deforms, the force transmission efficiency of the expansion tube 1 engaging with the connecting plate 100 is high. The cross-section matching between the claw plate 123 and the inverted tooth 121 in the middle section of the tube can reduce energy loss and improve the expansion accuracy. The structure has strong reliability. The large cross-section of the inverted tooth 121 in the middle section of the tube has strong overload resistance, and the small cross-section of the claw plate 123 is flexible and not easy to jam. It has a wide range of applicability. The claw plate 123 saves space and can be adapted to more pipe diameters. It is economical. The reinforced design of the inverted tooth 121 in the middle section of the tube extends its service life, and the lightweight claw plate 123 reduces material costs and reduces maintenance frequency, thus comprehensively improving the stability and cost performance of the expansion tube 1.

[0092] In one alternative embodiment, continue to refer to Figures 2 to 6 The orthographic projection of the expansion port 132 along the direction from the upper limiting notch 111 to the lower limiting notch 112 is an isosceles trapezoid. The isosceles trapezoid includes an upper base and a lower base that are arranged opposite each other. The upper base is located on the side of the lower base away from the front section 11 of the pipe. The upper base is smaller than the lower base. The upper base and the side of the rear section 13 away from the front section 11 of the pipe are on the same horizontal plane.

[0093] Specifically, on the side of the rear section 13 away from the front section 11, there is an expansion port 132 extending along the penetration direction of the first blind hole 131F; the orthographic projection of the expansion port 132 along the penetration direction of the first blind hole 131F is an isosceles trapezoid. The upper base of the isosceles trapezoid is smaller than its lower base; this smaller upper base facilitates the gradual widening of the expansion port 132 from the rear section 13 towards the front section 11, forming a progressive expansion guide structure. This ensures that the deformation of the expansion tube 1 under the action of the screw 2 smoothly transitions from the rear section 13 to the middle section 12, avoiding local stress concentration that could lead to tearing of the tube wall. The side of the expansion port 132 corresponding to its upper base is on the same horizontal plane as the side of the rear section 13 away from the front section 11.

[0094] With the above solution, the bottom edge of the expansion port 132 is flush with the end face of the rear section 13 of the tube, avoiding assembly jamming caused by the stepped structure. The isosceles trapezoidal expansion port 132 is narrow at the top and wide at the bottom, combined with the symmetrical waist-shaped design, so that the expansion tube 1 gradually expands from the rear section 13 to the middle of the tube under the action of the screw 2, avoiding tube wall tearing caused by excessive local deformation and improving structural durability.

[0095] In one alternative embodiment, continue to refer to Figures 2 to 6 A chamfer 133 is provided on the side of the rear section 13 away from the front section 11.

[0096] Specifically, a chamfer 133 is provided on the side of the rear section 13 away from the front section 11. When the eccentric button is tightened, because the maximum diameter of the eccentric button 3 conflicts with the minimum diameter of the first blind hole 131F and the second blind hole 131S, the chamfer 133 releases the diameter of the first blind hole 131F and the second blind hole 131S in the rear section 13. The chamfer 133 forms an angle with the end face of the rear section 13, with the axis of the expansion tube 1 as the reference. The chamfer 133 not only releases the diameter of the rear section 13, but also acts as a guide and buffer when the expansion tube 1 is inserted into the hole: when the rear section 13 contacts the edge of the hole, the chamfer 133 can guide the expansion tube 1 to smoothly enter the hole, reducing the feeling of jamming during assembly. Through the above solution, the chamfer 133 reduces the obstruction when the expansion tube 1 is inserted, and can still guide smoothly, especially when the hole position accuracy is low.

[0097] In one alternative embodiment, continue to refer to Figures 2 to 10 As shown, the outer wall of the rear section 13 of the tube is provided with a strip-shaped first rear section inverted tooth 135 and at least two levels of arc-shaped second rear section inverted teeth 136. The first rear section inverted tooth 135 is located on the side of the second rear section inverted tooth 136 near the middle section 12 of the tube. The at least two levels of second rear section inverted teeth 136 are arranged along the direction from the front section 11 to the rear section 13 and the circumferential direction of the second blind hole 131S. The length extension direction of the first rear section inverted tooth 135 is perpendicular to the arc length extension direction of the second rear section inverted tooth 136.

[0098] Along the direction from the upper limiting notch 111 to the lower limiting notch 112, the orthographic projections of the first pipe rear section reverse teeth 135 and the second pipe rear section reverse teeth 136 do not overlap with the orthographic projections of the first blind hole 131F and the second blind hole 131S.

[0099] Specifically, both the first and second rear section inverted teeth 135 and 136 are strip-shaped. The length extension direction of the first rear section inverted teeth 135 is the same as the length extension direction of the rear section 13. At least two first rear section inverted teeth 135 are provided along the circumference of the rear section 13; this embodiment only uses two as an example. The two first rear section inverted teeth 135 are symmetrically arranged with respect to the central axis of the rear section 13 or the length direction of the expansion port 132. One end of the first rear section inverted tooth 135 along its length direction is perpendicularly connected to the middle of the second rear section inverted tooth 136, and the connection is integrally formed. The length extension direction of the at least two-stage arc-shaped second rear section inverted teeth 136 is the circumference of the rear section 13. The second tube rear section inverted teeth 136 with at least two levels of arc are symmetrical about the central axis of the first blind hole 131F and the second blind hole 131S; along the direction from the upper limiting notch 111 to the lower limiting notch 112, the orthographic projections of the first tube rear section inverted teeth 135 and the second tube rear section inverted teeth 136 do not overlap with the orthographic projections of the first blind hole 131F and the second blind hole 131S.

[0100] With the above scheme, when the eccentric button 3 is rotated and fixed, and generates deformation pressure on the rear section 13 of the tube, the rear section 13 of the tube can further engage the end of the expansion tube 1 in the hole 011 of the plate through the first rear section reverse tooth 135 and the second rear section reverse tooth 136, so that the connection between the rear section 13 of the tube and the connecting plate 100 is more stable.

[0101] In one alternative embodiment, continue to refer to Figure 2 and Figure 4 As shown, the cross-sectional shape of the first pipe rear section reverse tooth 135 along the circumferential direction of the second blind hole 131S is a second isosceles triangle, and the cross-sectional shape of the second pipe rear section reverse tooth 136 along the direction from the upper limiting notch 111 to the lower limiting notch 112 is a second isosceles triangle. The tooth height of the first pipe rear section reverse tooth 135 is the same as the tooth height of the second pipe rear section reverse tooth 136; the tooth height of the second pipe rear section reverse tooth 136 is less than the tooth height of the pipe middle section reverse tooth 121.

[0102] Through the above scheme, the first tube's rear reverse teeth 135, when used to install the expansion tube 1 or screw 2, prevent the expansion tube 1 or screw 2 from rotating off-center. The tooth height of the second tube's rear reverse teeth 136 is less than the tooth height of the middle tube reverse teeth 121. This firstly makes it easier to apply torque and thrust when installing the tool 03 or embedding the screw 2, causing the middle tube reverse teeth 121 to press and bite into the plate. Furthermore, when rotating the eccentric knob 3, the torque locking force of the screw 2 is relatively large, sometimes making it impossible to properly turn the eccentric knob 3. The tooth height of the second tube's rear reverse teeth 136 is less than the tooth height of the middle tube reverse teeth 121, ensuring that the eccentric knob 3 can smoothly lock the screw 2. In an optional embodiment, continue to refer to... Figure 2 and Figure 12 As shown, the at least three-stage arc-shaped pipe mid-section inverted teeth 121 include a first sub-pipe mid-section inverted teeth 121A, a second sub-pipe mid-section inverted teeth 121B, and a third sub-pipe mid-section inverted teeth 121C. The first sub-pipe mid-section inverted teeth 121A, the second sub-pipe mid-section inverted teeth 121B, and the third sub-pipe mid-section inverted teeth 121C are arranged in the direction from the front section 11 of the pipe to the rear section 13 of the pipe.

[0103] Along the direction from the upper limit notch 111 to the lower limit notch 112, the tooth height of the inverted tooth 121A in the middle section of the first sub-tube is the same as that of the inverted tooth 121C in the middle section of the third sub-tube, and the tooth height of the inverted tooth 121B in the middle section of the second sub-tube is greater than that of the inverted tooth 121A in the middle section of the first sub-tube.

[0104] Specifically, due to the spindle-shaped smooth rod section 23, the expansion tube 1 preferentially begins to deform from the middle section inverted tooth 121, and the middle section inverted tooth 121B of the second sub-tube begins to participate in the stress. As the smooth rod section 23 advances, the middle section inverted teeth 121A and 121C of the first and third sub-tubes gradually come into contact with the claw plate 123 and participate in the stress. Since the tooth height of the middle section inverted tooth 121B of the second sub-tube is higher than the tooth height of the middle section inverted teeth 121A and 121C of the first and third sub-tubes on both sides, the deformation of the middle section inverted tooth 121 can be gradually extended from the middle to both ends, avoiding "lagging deformation" in the middle area due to the first stress on both sides, thereby reducing local stress concentration.

[0105] By controlling the force sequence and the force transmission path, the uniformity, stability and reliability of the deformation process of the inverted tooth 121 in the middle section of the pipe can be achieved through the above scheme.

[0106] In one alternative embodiment, continue to refer to Figures 2 to 8 As shown, an arc-shaped U-hole 32U is provided in the eccentric semicircular portion 3C along the direction from the eccentric semielliptical portion 3E to the eccentric semicircular portion 3C. The arc-shaped U-hole 32U penetrates the eccentric semicircular portion 3C along the direction from the eccentric semicircular portion 3C to the eccentric semielliptical portion 3E.

[0107] The eccentric semi-elliptical portion 3E has a first arc-shaped hole 32F and a second arc-shaped hole 32S connected in the direction from the eccentric semi-elliptical portion 3E to the eccentric semi-circular portion 3C. The second arc-shaped hole 32S is located on the side of the first arc-shaped hole 32F close to the arc-shaped U-hole 32U. The first arc-shaped hole 32F, the second arc-shaped hole 32S and the arc-shaped U-hole 32U are interconnected in the eccentric semi-circular portion 3C and the eccentric semi-elliptical portion 3E.

[0108] Along the direction perpendicular to the eccentric semi-elliptical portion 3E and pointing to the eccentric semi-circular portion 3C, the arc width of the first arc-shaped hole 32F is greater than the arc width of the second arc-shaped hole 32S.

[0109] Specifically, the arc-shaped U-hole 32U is a through hole penetrating the eccentric semi-elliptical portion 3C in a direction pointing from the eccentric semi-circular portion 3E to the eccentric semi-circular portion 3C. The U-shaped opening direction of the arc-shaped U-hole 32U is perpendicular to the axial direction of the eccentric semi-circular portion 3C. At least two anti-slip patterns 33 are provided along the eccentric semi-circular portion 3C corresponding to the positions of the arc-shaped U-hole 32U, and the length extension direction of the at least two anti-slip patterns 33 is perpendicular to the U-shaped opening direction of the arc-shaped U-hole 32U. The first arc-shaped hole 32F and the second arc-shaped hole 32S penetrate the eccentric semi-elliptical portion 3E in a direction pointing from the eccentric semi-circular portion 3C; in a direction perpendicular to the eccentric semi-elliptical portion 3E pointing from the eccentric semi-circular portion 3C, the arc width of the first arc-shaped hole 32F is greater than the arc width of the second arc-shaped hole 32S. The second arc-shaped hole 32S is located on the side of the first arc-shaped hole 32F near the arc-shaped U-hole 32U. The first arc-shaped hole 32F, the second arc-shaped hole 32S, and the arc-shaped U-hole 32U are interconnected within the eccentric semicircular portion 3C and the eccentric semi-elliptical portion 3E. The communicating cavity of the first arc-shaped hole 32F, the second arc-shaped hole 32S, and the arc-shaped U-hole 32U is used together to engage the end of the locking end 24 away from the smooth rod section 23. The first arc-shaped hole 32F, the second arc-shaped hole 32S, and the arc-shaped U-shaped hole 32U form an involute cam curve radially within the eccentric semicircular portion 3C and the eccentric semi-elliptical portion 3E. When the eccentric groove 31 rotates from 0° to 180°, the end of the locking end 24 away from the smooth rod section 23 moves radially within the first arc-shaped hole 32F, the second arc-shaped hole 32S, and the arc-shaped U-shaped hole 32U. The distance from the side of the tube rear section 13 corresponding to the first blind hole 131F to the central axis of the eccentric semicircular portion 3C decreases, resulting in a radial displacement of at least 2.5 mm, thereby pulling the locking end 24 into the screw cavity 10.

[0110] The connecting cavity between the first arc-shaped hole 32F, the second arc-shaped hole 32S, and the arc-shaped U-hole 32U is a precisely designed involute cam curve groove. The groove forms an involute cam curve within the eccentric semicircular portion 3C and the eccentric semielliptical portion 3E, exhibiting an eccentric offset characteristic with the central axis of the eccentric semicircular portion 3C and the eccentric semielliptical portion 3E as a reference. During the rotation from 0° to 180° of the eccentric semicircular portion 3C and the eccentric semielliptical portion 3E, the contact point between the inner wall of the eccentric semicircular portion 3C and the locking end 24 moves along the involute curve: at the initial position (0°), the locking end 24 contacts the farthest end of the inner wall of the connecting cavity between the first arc-shaped hole 32F, the second arc-shaped hole 32S, and the arc-shaped U-hole 32U. At this time, the eccentric semicircular portion 3C and the eccentric semielliptical portion 3E are at their central axis... The maximum distance is approximately 5 to 6 mm. As the rotation angle increases, the contact point gradually moves towards the proximal end of the eccentric hole 32, and the distance from the inner wall of the eccentric semicircular portion 3C and the eccentric semielliptical portion 3E to the central axis decreases accordingly. When the eccentric semicircular portion 3C and the eccentric semielliptical portion 3E rotate to 180°, the minimum distance is approximately 2.5 to 3.5 mm. The difference between the two forms a radial displacement space of at least 2.5 mm, thereby pulling the locking end 24 into the screw cavity 10.

[0111] Through the above scheme, the connecting cavity of the first arc-shaped hole 32F, the second arc-shaped hole 32S, and the arc-shaped U-shaped hole 32U of the involute cam curve guides the locking end 24 to gradually generate radial displacement from 0° to 180°. The total displacement of 2.5mm is controllable and uniform, avoiding locking failure caused by sudden displacement and ensuring a higher fit with the screw cavity 10. The opening of the eccentric hole 32 faces away from the eccentric groove 31, avoiding interference between the tool and the locking end 24 when the tool is inserted into the eccentric groove 31. During rotation, the contact point moves smoothly along the curve, reducing operating resistance.

[0112] In one alternative embodiment, the expansion tube 1 is made of plastic, and the screw 2 is made of steel.

[0113] Specifically, the expansion tube 1 is made of plastic, such as high-strength modified nylon or engineering plastic, and is injection molded. The screw 2 is made of steel, such as carbon structural steel, such as 45# steel, and is integrally cold-forged and then heat-treated with tempering, with the surface electroplated with zinc-nickel or Dacromet anti-rust layer.

[0114] The above solution combines steel and plastic components. The steel screw provides high pull-out force and rigidity, while the plastic shell protects the substrate, disperses stress, and prevents hole wall cracking. It is cost-effective; the plastic parts can be mass-produced, and screw 2 is a standard fastener, resulting in a lower overall cost compared to all-metal expansion bolts. Installation is convenient; the lightweight plastic shell reduces labor costs for both manual and automated assembly, and the universal thread of screw 2 is compatible with existing tools.

[0115] Example 2

[0116] This embodiment is an extension of embodiment 1, and will continue to be referred to... Figures 2 to 17 As shown, Figure 16 This is a side view of the decorative cover provided by this utility model; Figure 17 This is a variation diagram of the decorative cover installation provided by this utility model; this embodiment provides a connecting assembly, including a connecting plate 100, an expansion-type three-in-one connector 200, and a decorative cover 300, wherein the expansion-type three-in-one connector 200 is the aforementioned expansion-type three-in-one connector, wherein,

[0117] The connecting plate 100 is rectangular in shape. A hole 011 is provided on the front side of the connecting plate 100 near the edge. The hole 011 is recessed into the connecting plate 100 along the thickness direction. An end hole 012 communicating with the hole 011 is provided on the side of the connecting plate 100. An L-shaped hole is formed between the hole 011 and the end hole 012. The front section 11, the middle section 12 and the rear section 13 of the tube are respectively matched with the end hole 012.

[0118] The front section 11, the middle section 12 and the rear section 13 of the tube are inserted into the end hole 012. Along the thickness direction of the connecting plate 100, the orthographic projections of the eccentric semicircular part 3C and the eccentric semielliptical part 3E completely overlap with the orthographic projection of the plate hole 011.

[0119] The decorative cover 300 is fitted into the hole 011 of the panel. It includes a metal cover 42 and a fixing post 41 that is coaxially glued to the metal cover 42. The fixing post is placed inside the hole 011 of the panel. The side of the metal cover 42 away from the fixing post 41 is flush with the surface of the connecting plate.

[0120] The metal cover 42 and the fixing post 41 are both cylindrical structures, with the radius of the metal cover 42 being larger than that of the fixing post 41. The outer wall of the fixing post 41 has a fixing groove 411 recessed towards its central axis. The cross-sectional shape of the fixing groove 411 along the thickness direction of the connecting plate 100 is C-shaped, and the C-shaped opening of the fixing groove 411 is away from the central axis of the fixing post 41. A silicone ring 43 is fitted inside the fixing groove 411. The cross-section of the silicone ring 43 along the thickness direction of the connecting plate 100 is shaped like a figure 9. The circular end of the figure 9 in the silicone ring 43 is fitted into the fixing groove 411. The figure 9 in the silicone ring 43 rotates along the arc surface of the fixing groove 411, and the vertical part of the silicone ring 43 abuts against the side of the metal cover 42 near the fixing post 41.

[0121] Specifically, continue to refer to the above. Figures 2 to 15 The shape of the connecting plate 100 can be rectangular, arc-shaped or irregular. Of course, the shape of the connecting plate 100 can be designed according to the actual situation. This embodiment does not limit this. This embodiment only uses a rectangle as an example.

[0122] Based on currently available commercial products, the material and density of the connecting plate 100 can be arbitrarily selected. According to existing installation technology, a circular hole 011 is provided on the front side of the connecting plate 100 near its edge; along the thickness direction of the connecting plate 100, the hole 011 is a blind hole recessed into the interior of the connecting plate 100, but not penetrating through it. An end hole 012 communicating with the hole 011 is provided on the side of the connecting plate 100 closest to the hole 011; the hole 011 and the end hole 012 form an L-shaped hole inside the connecting plate 100; the front section 11, the middle section 12, and the rear section 13 of the tube are respectively matched with the end hole 012 along its depth direction. The front section 11, the middle section 12, and the rear section 13 of the tube are inserted into the end hole 012, and along the thickness direction of the connecting plate 100, the orthographic projections of the eccentric semicircular portion 3C and the eccentric semielliptical portion 3E completely overlap with the orthographic projection of the hole 011.

[0123] Continue to refer to the above. Figures 2 to 17 The decorative cover 300 is fitted onto the hole 011 in the panel. The decorative cover 300 is a cylinder of uneven thickness, which includes a metal cover 42 and a fixing post 41 coaxially glued to the metal cover 42. The fixing post is placed inside the hole 011 in the panel, and the side of the metal cover 42 away from the fixing post 41 is flush with the surface of the connecting plate.

[0124] Both the metal cover 42 and the fixing post 41 are cylindrical structures. The radius of the metal cover 42 is larger than the radius of the fixing post 41, and the radius of the metal cover 42 is smaller than the radius of the hole 011 in the plate. A fixing groove 411 recessed towards its central axis is formed on the outer wall of the fixing post 41. The length of the fixing groove 411 extends in the circumferential direction of the fixing post 41. The orthographic projection of the fixing groove 411 along the thickness direction of the connecting plate 100 is circular, and the cross-sectional shape of the fixing groove 411 along the thickness direction of the connecting plate 100 is C-shaped. The C-shaped opening of the fixing groove 411 is away from the central axis of the fixing post 41. A silicone ring 43 is fitted inside the fixing groove 411. The silicone ring 43 is used to increase the connection elasticity between the fixing post 41 and the connecting plate 100, allowing the fixing post 41 and the metal cover 42 to elastically engage with the connecting plate 100. The orthographic projection of the silicone ring 43 along the thickness direction of the connecting plate 100 is a hollow ring. The inner diameter of the silicone ring 43 is equal to the inner diameter of the fixing groove 411, and the outer diameter of the silicone ring 43 is larger than the diameter of the fixing post 41. The cross-section of the silicone ring 43 along the thickness direction of the connecting plate 100 is shaped like a figure 9. The circular end of the figure 9 in the silicone ring 43 is fitted into the C-shape of the fixing groove 411. The figure 9 in the silicone ring 43 rotates along the arc surface of the fixing groove 411, and the vertical part of the silicone ring 43 abuts against the side of the metal cover 42 near the fixing post 41.

[0125] The silicone ring 43 is made of an elastic material. Optionally, the silicone ring 43 can be made of materials with elastic properties such as silicone, rubber, or plastic. This embodiment does not limit the specific material of the silicone ring 43; this embodiment only uses the silicone ring 43 as an example. The fixing post 41 is made of plastic, specifically high-strength modified nylon or engineering plastic, and is injection molded.

[0126] In specific usage: First, as in Embodiment 1, the operations are performed sequentially from step one to step three. The expansion tube 1, screw 2, and eccentric knob 3 are installed in the connecting plate 100, such that the front section 11, middle section 12, and rear section 13 of the tube are inserted into the end hole 012. Along the thickness direction of the connecting plate 100, the orthographic projections of the eccentric semicircular portion 3C and the eccentric semielliptical portion 3E completely overlap with the orthographic projection of the plate hole 011. This embodiment will not elaborate further; please refer to the specific operating steps of Embodiment 1 above for details.

[0127] Then, fasten the decorative cover 300, fitting it into the hole 011 in the panel according to actual needs. Specifically, fasten the end of the fixing post 41 away from the metal cover 42 onto the hole 011, and press the metal cover 42 along the opening direction of the hole 011. The silicone ring 43 on the fixing post 41 moves into the hole 011 and rotates, achieving elastic fixation between the metal cover 42, the fixing post 41, and the hole 011. After installation, the side of the decorative cover 300 away from the fixing post 41 is flush with the surface of the connecting plate 100. When disassembly or maintenance is required, the decorative cover 300 can be removed by using a strong neodymium magnet.

[0128] Through the above solution, and by rotating and deforming the silicone ring 43 of the decorative cover 300, it can be tightly fastened inside the hole 011 of the board, preventing it from falling off due to hole diameter errors or vibrations or moving furniture. This reduces the requirement for the hole diameter accuracy of the decorative cover 300 on the board hole 011. Existing similar decorative covers are almost all higher than the board surface. This new decorative cover uses an elastic rubber ring, allowing the decorative cover to be flush with the board surface without protrusions, making it more aesthetically pleasing and comfortable. Furthermore, the diameter of the decorative cover 300 is the same as the hole diameter of the board hole 011 and is flush with the board surface of the connecting plate 100. The shortest length of the decorative cover 300 can be 2.5mm, and it is fixed by rotating and deforming the silicone ring 43, directly simplifying the design structure of the decorative cover 300 and reducing the visibility of the diameter of the decorative cover 300 by 70%.

[0129] In one alternative embodiment, continue to refer to Figure 17 As shown, the fixed post 41 has a hollow part 412 that is recessed towards the metal cover 42 at the end away from the metal cover 42. The hollow part 412 is cylindrical in shape.

[0130] Specifically, at the end of the fixing post 41 furthest from the metal cover 42, there is a recessed portion 412 that is recessed towards the metal cover 42. The recessed portion 412 is cylindrical in shape. The end of the recessed portion 412 furthest from the metal cover 42 is on the same plane as the end of the fixing post 41 furthest from the metal cover 42. The radius of the recessed portion 412 is not greater than the radius of the fixing post 41.

[0131] The above solution can further reduce the overall weight and manufacturing cost of the fixing post 41, which is conducive to increasing the fastening stability of the fixing post 41 when it is fastened upside down, and improving economic efficiency.

[0132] The various technical features of this utility model are mutually complementary and functionally supportive of each other. In other words, the technical solution is not a "simple superposition" of technical features among multiple prior art documents. Therefore, this utility model does not fall under the category of "simple superposition" in Chapter 4 of Part II of the Patent Examination Guidelines.

[0133] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. An expansion-type three-in-one connector, characterized in that, include: Expansion tube, screw, and eccentric knob, among which, The expansion tube includes a cylindrical section, a middle section, and a rear section connected sequentially along its length. Each of the three sections has a screw cavity at a position corresponding to its central axis. The screw cavities of the three sections are located on the same horizontal line. The front section of the tube includes a cylindrical front limiting section and a cylindrical front connecting section integrally connected to the front limiting section. The front connecting section is located on the side of the front limiting section near the middle section of the tube, and the side of the front connecting section away from the front limiting section is integrally connected to the side of the middle section near the front section of the tube. The front limiting section extends in the direction from the front section of the tube to the rear section of the tube. The front limiting section and the front connecting section are integrally coaxially connected. The outer wall of the side of the front limiting section away from the front connecting section is surrounded by an arc-shaped first front flange area and a second front flange area. The first front flange area and the second front flange area are distributed on opposite sides of the screw cavity. The tube front limiting section has an L-shaped upper limiting notch and a lower limiting notch respectively opened on the opposite sides of the screw cavity. In the direction from the tube front section to the tube rear section, the orthographic projection of the upper limiting notch and the lower limiting notch does not overlap with the orthographic projection of the first tube front flange area and the second tube front flange area. The outer wall of the middle section of the pipe is surrounded by at least three levels of arc-shaped inverted teeth. The at least three levels of inverted teeth are arranged along the direction from the front section of the pipe to the rear section of the pipe and along the circumference of the middle section of the pipe. The tooth height of each inverted tooth increases progressively. The cross-sectional shape of the inverted tooth perpendicular to its length extension direction is a first isosceles triangle. At least two deformation grooves are formed on the middle section of the pipe between adjacent inverted teeth. The at least two deformation grooves are arranged along the circumference of the middle section of the pipe and extend along the direction from the front section of the pipe to the rear section of the pipe. The deformation grooves are connected to the screw cavity of the middle section of the pipe. At least two claw plates are provided on the middle section of the pipe between two adjacent deformation grooves. Along the direction from the upper limiting notch to the lower limiting notch, a semi-elliptical first blind hole and a semi-circular second blind hole are provided on the rear section of the pipe near the middle section. A portion of the first blind hole penetrates the rear section of the pipe along the direction from the upper limiting notch to the lower limiting notch, while another portion of the first blind hole is recessed along the direction from the upper limiting notch to the lower limiting notch, and the first blind hole communicates with the screw cavity of the rear section of the pipe. Similarly, a portion of the second blind hole penetrates the rear section of the pipe along the direction from the upper limiting notch to the lower limiting notch, while another portion of the second blind hole is recessed along the direction from the upper limiting notch to the lower limiting notch, and the second blind hole communicates with the screw cavity of the rear section of the pipe. The first blind hole and the second blind hole communicate along the direction from the front section of the pipe to the rear section of the pipe. The first blind hole is located on the side of the second blind hole near the middle section of the pipe, and the opening portions of the first blind hole and the second blind hole are opposite each other. A portion of the first blind hole and a portion of the second blind hole are provided with an arc-shaped rib extending in the direction from the front section of the pipe to the rear section of the pipe, and the arc-shaped rib protrudes in the direction of the central axis of the rear section of the pipe; an expansion port communicating with the second blind hole is opened on the side of the rear section of the pipe away from the middle section of the pipe, and the expansion port penetrates the rear section of the pipe in the direction from the upper limiting notch to the lower limiting notch; Along the direction from the front section of the pipe to the rear section of the pipe, the screw includes an externally threaded section, a limiting flange, a smooth section, and a locking end connected in sequence. The limiting flange abuts against the first pipe front flange area and the second pipe front flange area. The smooth section is located in the front limiting section, the front connecting section, the middle section of the pipe, and part of the rear section of the pipe. The locking end is located in the rear section of the pipe. The smooth section is spindle-shaped. Along the circumferential direction of the second blind hole, the eccentric button includes an eccentric semicircular portion that matches the second blind hole and an eccentric semielliptical portion that is integrally connected to the eccentric semicircular portion. The eccentric semielliptical portion matches the first blind hole, and the eccentric semicircular portion and the eccentric semielliptical portion are respectively placed in the second blind hole and the first blind hole. The minor radius of the eccentric semi-elliptical portion is smaller than the radius of the eccentric semicircular portion. The eccentric semicircular portion has at least two triangular prism-shaped anti-slip patterns on the side away from the eccentric semi-elliptical portion. The at least two anti-slip patterns extend along the length direction of the first blind hole and are arranged along the circumferential direction of the second blind hole. The top of the eccentric semicircular portion and the eccentric semi-elliptical portion are provided with eccentric grooves that are recessed towards their bottom.

2. The expansion-type three-in-one connector according to claim 1, characterized in that, At least two of the claws are arranged along the direction from the front section of the tube to the rear section of the tube and along the circumferential direction of the second blind hole, with each claw close to the deformation groove side of the middle section of the tube; along the direction from the upper limiting notch to the lower limiting notch, the cross-sectional shape of the claw is triangular, and along the direction from the middle section of the tube to the screw cavity of the middle section of the tube, the cross-sectional shape of the claw is trapezoidal.

3. The expansion-type three-in-one connector according to claim 2, characterized in that, The trapezoidal cross-sectional area of ​​the claw is smaller than the cross-sectional area of ​​the first isosceles triangle of the inverted teeth in the middle section of the tube.

4. The expansion-type three-in-one connector according to claim 1, characterized in that, The orthographic projection of the expansion port along the direction from the upper notch of the limiting position to the lower notch of the limiting position is an isosceles trapezoid. The isosceles trapezoid includes an upper base and a lower base that are arranged opposite each other. The upper base is located on the side of the lower base away from the front section of the pipe. The upper base is smaller than the lower base. The upper base and the side of the rear section of the pipe away from the front section of the pipe are located on the same horizontal plane.

5. The expansion-type three-in-one connector according to claim 1, characterized in that, The outer wall of the rear section of the tube is provided with a strip-shaped first rear section inverted tooth and at least two levels of arc-shaped second rear section inverted teeth. The first rear section inverted tooth is located on the side of the second rear section inverted tooth closer to the middle section of the tube. The at least two levels of the second rear section inverted teeth are arranged along the direction from the front section of the tube to the rear section of the tube and along the circumferential direction of the second blind hole. The length extension direction of the first rear section inverted tooth is perpendicular to the arc length extension direction of the second rear section inverted tooth. Along the direction from the upper notch of the limiting point to the lower notch of the limiting point, the orthographic projections of the first pipe rear section inverted teeth and the second pipe rear section inverted teeth do not overlap with the orthographic projections of the first blind hole and the second blind hole.

6. The expansion-type three-in-one connector according to claim 1, characterized in that, The cross-sectional shape of the first tube rear section reverse tooth along the circumferential direction of the second blind hole is a second isosceles triangle, and the cross-sectional shape of the second tube rear section reverse tooth along the direction from the upper limiting notch to the lower limiting notch is a second isosceles triangle. The tooth height of the first tube rear section reverse tooth is the same as the tooth height of the second tube rear section reverse tooth. The tooth height of the reverse teeth in the rear section of the second tube is less than the tooth height of the reverse teeth in the middle section of the tube.

7. The expansion-type three-in-one connector according to claim 1, characterized in that, The at least three-level arc-shaped inverted teeth in the middle section of the tube include a first sub-tube middle section inverted teeth, a second sub-tube middle section inverted teeth, and a third sub-tube middle section inverted teeth, wherein the first sub-tube middle section inverted teeth, the second sub-tube middle section inverted teeth, and the third sub-tube middle section inverted teeth are arranged in a direction from the front section of the tube to the rear section of the tube; Along the direction from the upper notch of the limiting position to the lower notch of the limiting position, the tooth height of the reverse tooth in the middle section of the first sub-tube is the same as that of the reverse tooth in the middle section of the third sub-tube, and the tooth height of the reverse tooth in the middle section of the second sub-tube is greater than that of the reverse tooth in the middle section of the first sub-tube.

8. The expansion-type three-in-one connector according to claim 1, characterized in that, An arc-shaped U-hole is provided in the eccentric semicircular portion along the direction from the eccentric semielliptical portion to the eccentric semicircular portion, and the arc-shaped U-hole penetrates the eccentric semicircular portion along the direction from the eccentric semicircular portion to the eccentric semielliptical portion. The eccentric semi-elliptical portion has a first arc-shaped hole and a second arc-shaped hole connected in the direction from the eccentric semi-elliptical portion to the eccentric semi-circular portion. The second arc-shaped hole is located on the side of the first arc-shaped hole close to the arc-shaped U-hole. The first arc-shaped hole, the second arc-shaped hole and the arc-shaped U-hole are interconnected in the eccentric semi-circular portion and the eccentric semi-elliptical portion. Along a direction perpendicular to the eccentric semi-elliptical portion and pointing towards the eccentric semi-circular portion, the arc width of the first arc-shaped hole is greater than the arc width of the second arc-shaped hole.

9. A connecting component, characterized in that, include: The connector comprises a connecting plate, an expansion-type three-in-one connector, and a decorative cover, wherein the expansion-type three-in-one connector is any one of the expansion-type three-in-one connectors described in claims 1 to 8, wherein... The connecting plate is rectangular or arc-shaped, and a hole is formed on the front side of the connecting plate near the edge. Along the thickness direction of the connecting plate, the hole is recessed into the interior of the connecting plate. An end hole is formed on the side of the connecting plate, communicating with the hole. An L-shaped hole is formed between the hole and the end hole. The front section, the middle section, and the rear section of the tube are respectively matched with the end hole. The front section, the middle section, and the rear section of the tube are inserted into the end hole. Along the thickness direction of the connecting plate, the orthographic projections of the eccentric semicircular portion and the eccentric semielliptical portion completely overlap with the orthographic projections of the plate hole. The decorative cover fits into the hole in the panel, and includes a metal cover and a fixing post coaxially glued to the metal cover. The fixing post is placed inside the hole in the panel, and the side of the metal cover away from the fixing post is flush with the surface of the connecting plate. The metal cap and the fixing post are both cylindrical structures, with the radius of the metal cap being larger than the radius of the fixing post. The outer wall of the fixing post has a fixing groove recessed towards its central axis. The cross-sectional shape of the fixing groove along the thickness direction of the connecting plate is C-shaped, and the C-shaped opening of the fixing groove is away from the central axis of the fixing post. A silicone ring is fitted inside the fixing groove. The cross-sectional shape of the silicone ring along the thickness direction of the connecting plate is a figure-9 shape. The circular end of the figure-9 shape in the silicone ring is fitted into the fixing groove, and the figure-9 shape rotates along the arc surface of the fixing groove. The vertical portion of the silicone ring abuts against the side of the metal cap closest to the fixing post.

10. The connecting component according to claim 9, characterized in that, The fixed post has a recessed part at the end away from the metal cover, which is cylindrical in shape.

Images