Temporomandibular joint massager

Abstract

The invention relates to the technical field of temporomandibular joint massage, and discloses a temporomandibular joint massager. The temporomandibular joint massager comprises a head-mounted support and two massage boxes, wherein the head-mounted support is used for being worn on the head, and the two massage boxes are installed on the two sides of the head-mounted support respectively and can be attached to the left cheek and the right cheek respectively. A massage mechanism is mounted in the massage box, the massage mechanism comprises a driving mechanism and a massage part, the driving mechanism and the massage part are connected to the massage box, and the driving mechanism can drive the massage part to reciprocate between a massage position where the temporomandibular joint part can be massaged and a non-massage position away from the temporomandibular joint part. The temporomandibular joint massager can massage related acupuncture points and muscles of the temporomandibular joint so as to relieve pain caused by dysfunction of the temporomandibular joint.

Description

Technical Field

[0001] The present invention relates to the technical field of temporomandibular joint massage, and particularly to a temporomandibular joint massager. Background Art

[0002] Temporomandibular joint dysfunction is characterized by symptoms such as pain, clicking, and limited mouth opening in the temporomandibular joint area of the face. When temporomandibular joint dysfunction occurs, long-term massage of the temporomandibular joint area is an effective way to relieve pain. Long-term massage can relax local muscles, improve muscle tension and spasm states, promote blood circulation, and help relieve pain and improve joint mobility.

[0003] However, the pain attack time of temporomandibular joint dysfunction is random. When the pain attacks, people with temporomandibular joint dysfunction may be unable to massage their own temporomandibular joint area with both hands in time due to being busy with work or other matters. Summary of the Invention

[0004] The object of the present invention is to provide a temporomandibular joint massager that can massage the temporomandibular joint area.

[0005] To achieve the above object, the present invention provides a temporomandibular joint massager. The temporomandibular joint massager includes a head-mounted bracket for wearing on the head and two massage boxes. The two massage boxes are respectively installed on both sides of the head-mounted bracket and can respectively fit against the left cheek and the right cheek. A massage mechanism is installed in the massage box. The massage mechanism includes a driving mechanism and a massage member. The driving mechanism and the massage member are connected to the massage box. The driving mechanism can drive the massage member to reciprocate between a massage position where the temporomandibular joint area can be massaged and a non-massage position away from the temporomandibular joint area.

[0006] In some embodiments, the side of the massage box facing the human face is set as a first layer board; the massage member includes a transmission board and a plurality of flexible massage blocks installed on the transmission board. The transmission board is installed in the massage box, and all the flexible massage blocks can move through the first layer board to massage the cheek; the driving mechanism can drive the transmission board to drive all the flexible massage blocks to reciprocate between the massage position and the non-massage position.

[0007] In some embodiments, a plurality of support columns extending towards the human face side are installed on the transmission board. Elastic members are movably sleeved on the support columns, and one end of the elastic member is connected to the transmission board. A groove is provided on the side of the flexible massage block facing the transmission board. The other end of the elastic member is connected to the bottom wall of the groove. The end of the support column is movably inserted into the groove, and the end of the support column is spaced from the bottom wall of the groove by a preset distance.

[0008] In some embodiments, the driving mechanism includes a driving motor, a power source, a rotating shaft, a plurality of cams sleeved on the rotating shaft, and a plurality of elastic reset members. The driving motor and the power source are fixedly installed inside the massage box. The power source is electrically connected to the driving motor and can supply power to it. The rotating shaft is parallel to the first layer board. In the axial direction of the rotating shaft, the projections of all the cams coincide. The outer peripheral part of the cam contacts the surface of the transmission plate facing away from the first layer board. The massage box includes a second layer board distributed opposite to the first layer board. The transmission plate is connected to the second layer board through a plurality of elastic reset members distributed at intervals. Among them, the driving motor can drive the flexible massage block to move from the non-massage position to the massage position and can make the elastic reset members in a tension state. The elastic reset members in the tension state can drive the flexible massage block to move from the massage position to the non-massage position.

[0009] In some embodiments, a rotatable ball roller is embedded in the transmission plate, and the ball roller contacts the outer peripheral part of the cam.

[0010] In some embodiments, the temporomandibular joint massager further includes a hot compress box, and the hot compress box is detachably installed at the bottom of the massage box.

[0011] In some embodiments, a first mounting plate is connected to the bottom of the massage box, a second mounting plate is connected to the first mounting plate, and the second mounting plate is spaced apart from the bottom of the massage box to form a mounting area. The hot compress box is installed in the mounting area. A T-shaped groove is provided at the bottom of the massage box, and a T-shaped protrusion is provided at the top of the hot compress box. The T-shaped protrusion is movably inserted into the T-shaped groove.

[0012] In some embodiments, the head-mounted bracket includes a first bracket for wearing on the top of the head, a second bracket for wearing on the back of the head, and a third bracket for wearing on the lower jaw. Both ends of the above three are respectively connected to two massage boxes.

[0013] In some embodiments, the distance between the third bracket and the first bracket is adjustable.

[0014] In some embodiments, a vertically extending channel is provided in the second layer board. The end of the third bracket can be movably inserted into the channel, and the channel has side walls that can limit the sway of the end of the third bracket. A cavity is provided in the second layer board, and the cavity is connected to the channel. A gear that can rotate and be positioned is provided in the cavity. A rack meshing with the gear is provided at the end of the third bracket, and the length direction of the rack is consistent with the length direction of the channel. A bolt is provided on the second layer board. The rod portion of the bolt passes through the cavity and the gear is rotatably sleeved on the rod portion of the bolt. A stop ring is fixedly installed on the rod portion of the bolt, and the stop ring can press the gear against the side wall of the cavity to position the gear. The head of the bolt is located outside the second layer board and is used for screwing.

[0015] The above technical solutions of the present invention have the following beneficial effects:

[0016] The user can wear the temporomandibular joint massager on the head and adjust the wearing position so that the inner sides of the two massage boxes are respectively attached to the painful areas of the left cheek and the right cheek. At this time, the temporomandibular joint massager is worn. Then, the driving mechanism can be turned on, so that the massage member reciprocates between the massage position and the non-massage position under the drive of the driving mechanism. Among them, when the massage member is in the massage position, the end of the massage member facing the human face presses on the cheek, and by pressing the acupoints and muscles related to the temporomandibular joint on the cheek, the massage effect can be achieved, which can relieve pain for the user. Therefore, the temporomandibular joint massager of the present invention can massage the acupoints and muscles related to the temporomandibular joint to relieve the pain caused by temporomandibular joint dysfunction. Description of the Drawings

[0017] Figure 1 is a schematic diagram of the temporomandibular joint massager according to an embodiment of the present invention;

[0018] Figure 2 is a schematic diagram of the driving mechanism and the massage member according to an embodiment of the present invention;

[0019] Figure 3 is a schematic diagram of the connection between the support column and the flexible massage block according to an embodiment of the present invention;

[0020] Figure 4 is a schematic diagram of the engagement between the rack and the gear of the third bracket according to an embodiment of the present invention;

[0021] Figure 5 is a schematic diagram of the installation of the third bracket according to an embodiment of the present invention;

[0022] Figure 6 is a schematic diagram of the cooperation between the bolt and the gear according to an embodiment of the present invention.

[0023] Description of the Reference Numerals

[0024] 1. Head-mounted bracket; 11. First bracket; 12. Second bracket; 13. Third bracket; 2. Massage box; 21. First layer board; 22. Second layer board; 3. Massage mechanism; 31. Driving mechanism; 311. Driving motor; 312. Rotating shaft; 313. Cam; 32. Massage member; 321. Transmission board; 322. Flexible massage block; 323. Elastic reset member; 324. Elastic member; 325. Support column; 326. Groove; 327. Ball roller; 4. First mounting board; 5. Second mounting board; 6. Channel; 61. Cavity; 7. T-shaped convex block; 8. Rack; 81. Gear; 82. Bolt; 83. Stop ring; 9. Hot compress box. Detailed Embodiment

[0025] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0026] In the present invention, unless otherwise specified, the orientation terms such as "upper" and "lower" generally refer to the orientation in the assembled and used state. "Inner" and "outer" refer to the inner and outer of the contour of each component itself.

[0027] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances for the embodiments of the present invention described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0028] As Figure 1 shown, the present invention provides a temporomandibular joint massager. The temporomandibular joint massager includes a head-mounted bracket 1 for wearing on the head and two massage boxes 2. The two massage boxes 2 are respectively installed on both sides of the head-mounted bracket 1 and can respectively fit against the left cheek and the right cheek. A massage mechanism 3 is installed in the massage box 2. The massage mechanism 3 includes a driving mechanism 31 and a massage member 32. The driving mechanism 31 and the massage member 32 are connected to the massage box 2. The driving mechanism 31 can drive the massage member 32 to reciprocate between a massage position where it can massage the temporomandibular joint area and a non-massage position away from the temporomandibular joint area.

[0029] Specifically, the user can wear the temporomandibular joint massager on the head and adjust the wearing position so that the inner sides of the two massage boxes 2 respectively fit against the painful areas of the left cheek and the right cheek. At this time, the temporomandibular joint massager is worn. Then, the driving mechanism 31 can be turned on, and the massage member 32 is driven by the driving mechanism 31 to reciprocate between the massage position and the non-massage position. Among them, when the massage member 32 is in the massage position, the end of the massage member 32 facing the human face presses on the cheek. By pressing the acupoints and muscles on the cheek related to the temporomandibular joint, the massage effect is achieved, and the pain of the user can be relieved. Therefore, the temporomandibular joint massager of the present invention can massage the acupoints and muscles related to the temporomandibular joint to relieve the pain caused by temporomandibular joint dysfunction.

[0030] In addition, the switch of the drive motor 311 can be arranged outside the second layer plate 22 for easy operation by the user. Of course, the switch of the drive motor 311 can also be a hand-held remote control switch that is signal-connected to the drive motor 311.

[0031] As Figure 2 shown, in some embodiments of the present invention, the side of the massage box 2 facing the human face is set as the first layer plate 21; the massage member 32 includes a transmission plate 321 and a plurality of flexible massage blocks 322 mounted on the transmission plate 321. The transmission plate 321 is installed inside the massage box 2, and all the flexible massage blocks 322 can move through the first layer plate 21 to massage the cheeks; the driving mechanism 31 can drive the transmission plate 321 to drive all the flexible massage blocks 322 to reciprocate between a massage position and a non-massage position.

[0032] Specifically, the driving mechanism 31 drives the transmission plate 321 to reciprocate between a massage position and a non-massage position, and the flexible massage blocks 322 mounted on the transmission plate 321 move together with the transmission plate 321. When the flexible massage blocks 322 are in the massage position, the end of the flexible massage block 322 facing the human face presses on the human face, thereby realizing the massage of the acupoints related to the temporomandibular joint.

[0033] As Figure 3 shown, in some embodiments of the present invention, a plurality of support columns 325 extending toward the human face side are mounted on the transmission plate 321, and an elastic member 324 is movably sleeved on the support column 325. One end of the elastic member 324 is connected to the transmission plate 321. A groove 326 is provided on the side of the flexible massage block 322 facing the transmission plate 321, and the other end of the elastic member 324 is connected to the bottom wall of the groove 326. The end of the support column 325 is movably inserted into the groove 326, and the end of the support column 325 is spaced apart from the bottom wall of the groove 326 by a preset distance. It should be noted that the preset distance refers to the distance between the end of the support column 325 and the bottom wall of the groove 326 in the natural state of the elastic member 324.

[0034] Specifically, the massage member 32 is driven by the driving mechanism 31 to move towards the human face side. Before the end of the flexible massage block 322 facing the human face comes into contact with the cheek, the elastic member 324 can be in a natural state without compression or elongation. During the process from the end of the flexible massage block 322 facing the human face starting to contact the cheek to reaching the massage position, the elastic member 324 is gradually compressed under force, and the end of the support column 325 gradually approaches the bottom wall of the groove 326. With such a setting, on the one hand, the contact between the flexible massage block 322 and the cheek is an elastic contact, which can improve the comfort of massage; on the other hand, setting a compressible preset distance for each flexible massage block 322 enables the flexible massage block 322 to compress itself according to the height of the corresponding cheek part, enabling the flexible massage block 322 to fit the curved surface of the human cheek for massage and making the massage force received by different parts of the cheek relatively uniform.

[0035] In some embodiments, the elastic member 324 can be set as a spring or a rubber tube, etc., but a spring is preferably used.

[0036] In some embodiments of the present invention, the driving mechanism 31 includes a driving motor 311, a power source, a rotating shaft 312, a plurality of cams 313 sleeved on the rotating shaft 312, and a plurality of elastic reset members 323. The driving motor 311 and the power source are fixedly installed inside the massage box 2. The power source is electrically connected to the driving motor 311 and can supply power to it. The rotating shaft 312 is parallel to the first layer plate 21. In the axial direction of the rotating shaft 312, the projections of all the cams 313 coincide. The outer peripheral part of the cam 313 contacts the surface of the transmission plate 321 facing away from the first layer plate 21. The massage box 2 includes a second layer plate 22 distributed opposite to the first layer plate 21. The transmission plate 321 is connected to the second layer plate 22 through a plurality of elastically spaced reset members 323. Among them, the driving motor 311 can drive the flexible massage block 322 to move from the non-massage position to the massage position and can make the elastic reset member 323 in a tensioned state. The elastic reset member 323 in the tensioned state can drive the flexible massage block 322 to move from the massage position to the non-massage position.

[0037] Specifically, when the driving motor 311 operates, the cam 313 rotates with the rotation of the rotating shaft 312, and the outer peripheral part of the cam 313 always contacts the surface of the transmission plate 321 facing away from the first layer plate 21. When the convex part of the cam 313 rotates to contact the surface of the transmission plate 321 facing away from the first layer plate 21, the transmission plate 321 is extruded by the cam 313 and moves towards the first layer plate 21, so that the flexible massage block 322 moves towards the massage position to press the cheek, and the elastic reset member 323 is stretched. When the convex part of the cam 313 rotates away from the transmission plate 321, the transmission plate 321 moves in the direction away from the first layer plate 21 under the pull of the elastic reset member 323, and the flexible massage block 322 leaves the cheek and enters the non-massage position.

[0038] In addition, the switch of the drive motor 311 can be set at the second layer board 22 and exposed, so as to facilitate the user to operate the switch. Of course, the switch of the drive motor 311 can also be a hand-held remote control switch, which is signal-connected to the drive motor 311, and the user controls the operation of the drive motor 311 by manipulating the hand-held remote control switch.

[0039] In some embodiments of the present invention, ball rollers 327 are movably embedded in the transmission plate 321, and the ball rollers 327 are in contact with the outer peripheral portion of the cam 313, which can make the rotation of the outer peripheral portion of the cam 313 relative to the transmission plate 321 smoother.

[0040] In some embodiments of the present invention, the temporomandibular joint massager further includes a hot compress box 9, and the hot compress box 9 is detachably installed at the bottom of the massage box 2.

[0041] Specifically, the hot compress box 9 is provided with a water injection structure that can be opened and closed. When hot compress is needed, hot water can be injected into the hot compress box 9 from the water injection structure, and when the hot compress is over, the water can be discharged from the water injection structure.

[0042] In some embodiments of the present invention, a first mounting plate 4 is connected to the bottom of the massage box 2, a second mounting plate 5 is connected to the first mounting plate 4, and the second mounting plate 5 is spaced apart from the bottom of the massage box 2 to form a mounting area. The hot compress box 9 is installed in the mounting area. A T-shaped groove is provided at the bottom of the massage box 2, and a T-shaped protrusion 7 is provided at the top of the hot compress box 9. The T-shaped protrusion 7 is movably inserted into the T-shaped groove.

[0043] Specifically, the top of the first mounting plate 4 is connected to the bottom of the second layer board 22, the second mounting plate 5 is horizontally arranged, and one end thereof close to the second layer board 22 is connected to the bottom of the first mounting plate 4. In the direction perpendicular to the first layer board 21, the first mounting plate 4 and the second mounting plate 5 are connected in an L shape. When the hot compress box 9 is installed in the mounting area, the top surface of the hot compress box 9 is in contact with the bottom surface of the massage box 2, one side of the hot compress box 9 facing away from the first layer board 21 is in contact with the first mounting plate 4, and the bottom surface of the hot compress box 9 is in contact with the second mounting plate 5. A T-shaped groove is provided at the bottom of the massage box 2, and a T-shaped protrusion 7 is provided at the top of the hot compress box 9, which can make the hot compress box 9 more firmly installed in the mounting area. Of course, the upper width of the T-shaped groove is greater than its lower width, and the upper width of the T-shaped protrusion 7 is greater than its lower width, so as to facilitate the fixation of the hot compress box 9 after the two are matched.

[0044] In some embodiments of the present invention, the head-mounted bracket 1 includes a first bracket 11 worn on the top of the head, a second bracket 12 worn on the back of the head, and a third bracket 13 worn on the lower jaw, and both ends of the above three are respectively connected to two massage boxes 2.

[0045] Specifically, the first bracket 11, the second bracket 12, and the third bracket 13 are respectively U-shaped or C-shaped brackets, which are respectively worn at different positions on the head, and the three brackets together make the massage box 2 fit on the user's cheek part.

[0046] In some embodiments, the first bracket 11, the second bracket 12, and the third bracket 13 can also be set as elastic bands. Those skilled in the art can select the structure and material of the head-mounted bracket 1 that can firmly wear the massage box 2 according to needs, and the present invention does not make limitations.

[0047] In some embodiments of the present invention, the distance between the third bracket 13 and the first bracket 11 is adjustable, so that the head-mounted bracket 1 can adapt to different users.

[0048] Such as Figure 1 、 Figure 4 、 Figure 5 and Figure 6 As shown, in some embodiments of the present invention, a vertically extending channel 6 is provided in the second layer plate 22. The end of the third bracket 13 can be movably inserted into the channel 6, and the channel 6 has side walls that can limit the sway of the end of the third bracket 13; a cavity 61 is provided in the second layer plate 22, and the cavity 61 is communicated with the channel 6. A gear 81 that can rotate and be positioned is provided in the cavity 61. A rack 8 that meshes with the gear 81 is provided at the end of the third bracket 13, and the length direction of the rack 8 is the same as the length direction of the channel 6. A bolt 82 is provided on the second layer plate 22. The rod portion of the bolt 82 passes through the cavity 61 and the gear 81 is rotatably sleeved on the rod portion of the bolt 82. A stop ring 83 is fixedly installed on the rod portion of the bolt 82. The stop ring 83 can press the gear 81 against the side wall of the cavity 61 to position the gear 81. The head of the bolt 82 is located outside the second layer plate 22 and is used for screwing.

[0049] Specifically, when the user wears the headband bracket, the head of the bolt 82 can be screwed in the reverse direction so that the stop ring 83 no longer presses the gear 81 against the side wall of the cavity 61. At this time, the gear 81 can rotate. Then the third bracket 13 is pulled down, the rack 8 at the end of the third bracket 13 descends, and the gear 81 meshing with the rack 8 will rotate around the rod portion of the bolt 82. After wearing, the user pushes up the third bracket 13. When it is adjusted to the appropriate position, then screw the head of the bolt 82 in the forward direction so that the stop ring 83 presses the gear 81 against the side wall of the cavity 61. The gear 81 no longer rotates and the gear 81 clamps and positions the rack 8, thereby fixing the position of the third bracket 13.

[0050] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0051] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any appropriate manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination manners.

[0052] Furthermore, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A temporomandibular joint massager, characterized in that: The invention comprises a head-mounted bracket (1) for being worn on the head and two massage boxes (2), wherein the two massage boxes (2) are respectively mounted on both sides of the head-mounted bracket (1) and can be respectively fitted on the left cheek and the right cheek. A massage mechanism (3) is installed in the massage box (2), and the massage mechanism (3) comprises a driving mechanism (31) and a massage piece (32). The driving mechanism (31) and the massage piece (32) are connected to the massage box (2), and the driving mechanism (31) can drive the massage piece (32) to move back and forth between a massage position capable of massaging the temporomandibular joint and a non-massage position away from the temporomandibular joint.

2. The temporomandibular joint massager according to claim 1, characterized in that: The side of the massage box (2) facing the human face is set as a first layer plate (21); the massage element (32) comprises a transmission plate (321) and a plurality of flexible massage blocks (322) mounted on the transmission plate (321); the transmission plate (321) is mounted in the massage box (2); all the flexible massage blocks (322) can move through the first layer plate (21) to massage the cheeks; the driving mechanism (31) can drive the transmission plate (321) to drive all the flexible massage blocks (322) to move back and forth between the massage position and the non-massage position.

3. The temporomandibular joint massager according to claim 2, characterized in that: The transmission plate (321) is provided with a plurality of support columns (325) extending toward one side of the human face, and an elastic member (324) is movably sleeved on the support column (325), and one end of the elastic member (324) is connected to the transmission plate (321); A groove (326) is provided on one side of the flexible massage block (322) facing the transmission plate (321); the other end of the elastic member (324) is connected to the bottom wall of the groove (326); the end of the support column (325) is movably inserted into the groove (326); and the end of the support column (325) is spaced apart from the bottom wall of the groove (326) by a preset distance.

4. The temporomandibular joint massager according to claim 3, characterized in that: The driving mechanism (31) comprises a driving motor (311), a power source, a rotating shaft (312), a plurality of cams (313) sleeved on the rotating shaft (312), and a plurality of elastic reset members (323); the driving motor (311) and the power source are fixedly installed inside the massage box (2); the power source is electrically connected to the driving motor (311) and can supply power to the driving motor (311); the rotating shaft (312) is parallel to the first layer plate (21); in the axial direction of the rotating shaft (312), the projections of all the cams (313) overlap; the outer periphery of the cam (313) contacts the side of the transmission plate (321) facing away from the first layer plate (21); The massage box (2) comprises a second layer plate (22) arranged opposite to the first layer plate (21), and the transmission plate (321) is connected to the second layer plate (22) via a plurality of elastic reset members (323) arranged at intervals; Wherein, the driving motor (311) can drive the flexible massage block (322) to move from the non-massage position to the massage position and can put the elastic reset member (323) in a tensioned state; The elastic reset member (323) in the tensioned state can drive the flexible massage block (322) to move from the massage position to the non-massage position.

5. The temporomandibular joint massager according to claim 4, characterized in that: A rotatable ball roller (327) is embedded in the transmission plate (321), and the ball roller (327) is in contact with the outer periphery of the cam (313).

6. The temporomandibular joint massager according to claim 2, characterized in that: The temporomandibular joint massager further comprises a hot compress box (9), and the hot compress box (9) is detachably mounted on the bottom of the massage box (2).

7. The temporomandibular joint massager according to claim 6, characterized in that: The bottom of the massage box (2) is connected to a first mounting plate (4), the first mounting plate (4) is connected to a second mounting plate (5), the second mounting plate (5) is spaced apart from the bottom of the massage box (2) to form a mounting area, the hot compress box (9) is mounted in the mounting area, the bottom of the massage box (2) is provided with a T-shaped groove, the top of the hot compress box (9) is provided with a T-shaped protrusion (7), and the T-shaped protrusion (7) is movably inserted into the T-shaped groove.

8. The temporomandibular joint massager according to claim 5, characterized in that: The head-mounted bracket (1) comprises a first bracket (11) for wearing on the top of the head, a second bracket (12) for wearing on the back of the head, and a third bracket (13) for wearing on the lower jaw, and both ends of the three brackets are respectively connected to the two massage boxes (2).

9. The temporomandibular joint massager according to claim 8, characterized in that: The distance between the third bracket (13) and the first bracket (11) is adjustable.

10. The temporomandibular joint massager according to claim 9, characterized in that: A vertically extending channel (6) is provided in the second layer plate (22), and the end of the third bracket (13) can be movably inserted into the channel (6), and the channel (6) has a side wall capable of limiting the shaking of the end of the third bracket (13); a cavity (61) is provided in the second layer plate (22), and the cavity (61) is connected to the channel (6), and a gear (81) capable of rotation and positioning is provided in the cavity (61), and a rack (8) meshing with the gear (81) is provided at the end of the third bracket (13), and the length of the rack (8) is The second plate (22) is provided with a bolt (82), wherein the rod of the bolt (82) passes through the cavity (61) and the gear (81) is rotatably sleeved on the rod of the bolt (82), and a stop ring (83) is fixedly installed on the rod of the bolt (82), and the stop ring (83) can press the gear (81) against the side wall of the cavity (61) to position the gear (81), and the head of the bolt (82) is located on the outer side of the second plate (22) and is used for screwing.

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