Writing board lifting structure, universal board, combined board and multifunctional board

Abstract

The utility model relates to the technical field of office and teaching equipment, in particular to a writing board lifting structure, a universal board, a combined board and a multifunctional board. The lifting structure comprises a fixing frame, a supporting mechanism and a lifting frame; the fixing frame is fixedly installed, the lifting frame is used for installing a writing board, and the lifting frame is installed on the fixing frame in a sliding mode and can ascend and descend relative to the fixing frame; the axis of the supporting mechanism and the horizontal plane form a preset angle range, the top end of the supporting mechanism is rotationally connected with the fixing frame, the bottom end of the supporting mechanism is rotationally connected with the lifting frame, and resistance of the fixing frame to the lifting frame can enable the lifting frame to hover at any position in the vertical direction. The overall weight is remarkably reduced, the installation process is simplified, and the technical effects that the writing board is smooth in lifting process and stable in hovering at any position are achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to office and teaching equipment technical field especially relates to a writing board lifting structure, universal board, combination board and multi -functional board. BACKGROUND

[0002] Writing board is widely used in education, office, display and other fields, and the traditional writing board is mostly fixed design, which cannot adapt to the writing needs of users with different heights or different scenes. To solve this problem, a lifting writing board structure appears in the prior art, which realizes height adjustment of the writing board through the lifting structure to improve the flexibility and convenience of use. The writing board lifting structure is mainly used for adjusting the height of the writing board to adapt to the needs of users with different heights or to switch the writing area in teaching and meeting scenes. Its core principle is to offset the gravity of the writing board and the lifting frame through a mechanical balance device to realize labor-saving operation and position hovering function in the lifting process.

[0003] The existing lifting structure is a lifting structure based on counterweight, which mainly includes a fixed frame, a lifting frame, a counterweight and a pull wire assembly. The fixed frame is vertically installed on the wall or support, and the lifting frame is slidably connected with the fixed frame through a guide rail to carry the writing board. The counterweight is connected with the lifting frame through a pull wire around a roller: when the lifting frame descends, the counterweight rises; on the contrary, the counterweight descends. This structure uses the gravity of the counterweight to offset the gravity of the writing board and the lifting frame, thereby realizing the balance of lifting operation.

[0004] The lifting structure in the form of counterweight has the following problems:

[0005] ① The overall weight is too large: the counterweight needs to match the gravity of the writing board and the lifting frame, which significantly increases the total mass of the device and the transportation and installation cost is high;

[0006] ② Installation and debugging are complex: the length of the pull wire and the weight of the counterweight need to be accurately adjusted to ensure balance, which is time-consuming and prone to safety hazards due to debugging errors;

[0007] ③ Insufficient reliability: the pull wire is prone to wear or breakage during long-term use, and the counterweight may cause safety accidents due to stall falling;

[0008] ④ Large space occupation: the counterweight needs additional installation space, which limits the compactness of the structure. UTILITY MODEL CONTENTS

[0009] In view of the deficiencies of the prior art, the purpose of the utility model embodiment is to provide a lightweight, high-safety writing board lifting structure, which replaces the traditional counterweight block assembly by a supporting mechanism, significantly reduces the overall weight and simplifies the installation process. At the same time, the supporting mechanism is arranged obliquely, dynamically adjusts the mechanical component force of the lifting frame, solves the problem of getting heavier caused by vertically arranging the supporting mechanism, and finally realizes the technical effects of smooth writing board lifting process and stable hovering at any position.

[0010] In order to realize the above-mentioned purpose, the utility model embodiment provides the following technical scheme:

[0011] A writing board lifting structure comprises a fixed frame, a supporting mechanism and a lifting frame; the fixed frame is fixedly installed, the lifting frame is used for installing a writing board, the lifting frame is slidingly installed on the fixed frame and can be lifted and moved relative to the fixed frame; the axis of the supporting mechanism is at a preset angle range with the horizontal plane, the top end of the supporting mechanism is rotationally connected with the fixed frame, the bottom end of the supporting mechanism is rotationally connected with the lifting frame, and the resistance of the fixed frame to the lifting frame can make the lifting frame hover at any position in the vertical direction.

[0012] Optionally, the preset angle range is 15°-50°.

[0013] Optionally, F0 / G=x is set, wherein F0 is the supporting force provided by the gas spring, G is the total gravity of the writing board and the lifting frame, and the range of x is 1.2-1.4.

[0014] Optionally, the top end of the supporting mechanism is rotationally connected with the top frame of the fixed frame, and the bottom end is rotationally connected with the side frame of the lifting frame; or the top end of the supporting mechanism is rotationally connected with the side frame of the fixed frame, and the bottom end is rotationally connected with the bottom frame of the lifting frame.

[0015] Optionally, the supporting mechanism comprises a supporting rod and a fixed seat, the fixed seat is hingedly installed at the top end and the bottom end of the supporting rod, the fixed seat at the top end is fixedly connected with the lifting frame, and the fixed seat at the bottom end is fixedly connected with the fixed frame.

[0016] Optionally, the hinge points of the supporting rod and the fixed seat adopt a mounting mode of pin shaft cooperating with bearing.

[0017] Optionally, the supporting mechanism comprises a supporting rod, and the supporting rod is a gas spring or a hydraulic damping rod.

[0018] Optionally, the gas spring comprises a cylinder body, a piston and a piston rod, the cylinder body is filled with gas, the piston is installed in the cylinder body, no inner sealing ring is installed between the piston and the cylinder body, and one end of the piston rod is connected with the piston.

[0019] Optionally, the cylinder body is rotationally connected with the lifting frame, and the piston rod is rotationally connected with the fixed frame; or the cylinder body is rotationally connected with the fixed frame, and the piston rod is rotationally connected with the lifting frame.

[0020] Optionally, the fixed frame comprises side frames on the left and right sides and bending plates on the upper and lower ends, the bending plate comprises a horizontal plate and a vertical plate, the horizontal plate is provided with a mounting hole for fixation, and the vertical plate is provided with an adjusting hole, which is a horizontally arranged long slot, and the bending plate is mounted on the side frame through the long slot.

[0021] Optionally, the back surface of the lifting frame is provided with a lifting guide slot, and the front surface of the side frame is provided with a lifting guide wheel set, the lifting guide wheel set comprises at least two guide wheels arranged alternately left and right, and the lifting guide wheel set slides in the lifting guide slot.

[0022] The utility model also provides a universal board, including writing board and writing board lifting structure as described above, the back surface of writing board is provided with horizontal moving guide slot, the front surface of lifting frame is provided with horizontal moving guide wheel set, horizontal moving guide wheel set includes at least two guide wheels arranged alternately up and down, and horizontal moving guide wheel set slides in horizontal moving guide slot.

[0023] The utility model also provides a combination board, including at least two universal boards as described above, and all the universal boards are arranged in the same vertical plane.

[0024] The utility model also provides a multifunctional board, including display screen and universal board as described above, and the universal board is located on the left and right sides of the display screen; or the universal board is located on the upper and lower sides of the display screen.

[0025] The one or more technical solutions provided in the embodiments of the utility model have at least the following technical effects or advantages:

[0026] 1、 the writing board lifting structure, through support mechanism balance writing board and the weight of fixed frame, compared with traditional counterweight scheme, this lifting structure reduces the overall weight, improves the convenience of transportation and installation;Reduce the debugging step, save installation time;Through more stable mechanical structure, avoid the security risk caused by component failure;Need not reserve installation space for counterweight, and the overall structure is more compact.

[0027] 2. The support mechanism is obliquely installed, the top end is rotationally connected with the fixing frame, and the bottom end is rotationally connected with the lifting frame. Through the oblique arrangement of the support mechanism, the component force of the support mechanism on the lifting frame is dynamically adjusted, the problem that the weight becomes heavier and heavier caused by vertically arranging the support mechanism is avoided, and the lifting process is more smooth. The difference between the total weight of the writing board and the lifting frame and the force of the gas spring is less than the frictional resistance of the gas spring, so that the writing board can stably hover at any position, and the difference is not zero, so that the writing board is easy to operate during lifting, and the use experience is improved.

[0028] The advantages of the additional aspects of the utility model will be given in the following description, some of which will become apparent from the following description, or be understood through practice of the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiment or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments described in the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor. In addition, the mutual distance or size is exaggerated to show the position of each component, and the schematic diagram is only used for illustration.

[0030] Figure 1 is a front view of the lifting structure provided by the utility model embodiment;

[0031] Figure 2 is a back view of the lifting structure provided by the utility model embodiment;

[0032] Figure 3 is a schematic view of the fixing frame provided by the utility model embodiment;

[0033] Figure 4 is a schematic view of the fixing frame and the lifting frame provided by the utility model embodiment;

[0034] Figure 5 is a schematic view of the support mechanism provided by the utility model embodiment;

[0035] Figure 6 is a schematic view of the gas spring (right side) and the conventional gas spring (left side) provided by the utility model embodiment;

[0036] Figure 7 is a schematic view of three states of the lifting structure provided by the utility model embodiment;

[0037] Figure 8 is a schematic view of the universal plate provided by the utility model embodiment;

[0038] Figure 9It is the writing board and the cooperation schematic view of the lifting frame provided by the embodiment of the utility model;

[0039] Figure 10 It is the multifunctional board schematic view provided by the embodiment of the utility model;

[0040] In the drawing: 1, fixed frame; 11, side frame; 12, lifting guide wheel set; 13, mounting hole; 14, bending plate; 15, adjusting hole; 2, lifting frame; 21, lifting guide slot; 3, supporting mechanism; 31, gas spring; 311, cylinder body; 312, piston; 313, piston rod; 314, outer sealing ring; 315, inner sealing ring; 32, fixed seat; 4, writing board; 41, transverse movement guide slot; 42, transverse movement guide wheel set; 5, display screen; DETAILED DESCRIPTION

[0041] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the utility model. Unless otherwise specified, all technical and scientific terms used in the utility model have the same meaning as that generally understood by ordinary skilled persons in the technical field to which the utility model belongs. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in the specification, they indicate the presence of a feature, step, operation, device, component and / or their combination.

[0042] Embodiment 1

[0043] As shown in Figure 1 , Figure 2 , the embodiment provides a writing board 4 lifting structure, the writing board 4 can be blackboard, whiteboard, magnetic board, light energy board and the like, and the lifting structure can also be used in other various board structures.

[0044] The lifting structure includes a fixed frame 1, a supporting mechanism 3 and a lifting frame 2; the fixed frame 1 is fixedly installed, the lifting frame 2 is used for installing the writing board 4, the lifting frame 2 is slidingly installed on the fixed frame 1 and can be lifted and moved relative to the fixed frame 1; the axis of the supporting mechanism 3 is at a preset angle range with the horizontal plane, the top end of the supporting mechanism 3 is rotationally connected with the fixed frame 1, and the bottom end of the supporting mechanism 3 is rotationally connected with the lifting frame 2, wherein the upward component force of the supporting mechanism 3 on the lifting frame 2 is F, the maximum resistance of the fixed frame 1 on the lifting frame 2 when the lifting frame 2 is lifted is Fr, Fe is the friction between the lifting frame and the fixed frame, the gravity of the writing board 4 and the lifting frame 2 is G, and at any position of the lifting frame in the vertical direction, the absolute value of the difference between F and G is not greater than Fr+Fe, so that the writing board can be stably hovered at any position.

[0045] When the installation of the support mechanism (i.e. gas spring) is in the vertical state with the piston rod at the lower end, as the writing board is lowered, the gas spring is gradually compressed, making the upward support force provided by the gas spring increasingly large, resulting in the writing board being pulled down increasingly heavy. Conversely, if the installation of the gas spring is with the piston rod at the upper end, as the writing board is raised, the gas spring is gradually compressed, making the upward support force provided by the gas spring increasingly large, resulting in the writing board being pushed up increasingly heavy.

[0046] When the piston rod is at the lower end, the writing board has a first position and a second position during the lowering process, where the second position is lower than the first position, the angle between the gas spring and the vertical direction at the first position is a1, at this time the support force of the gas spring is f1; the angle between the gas spring and the vertical direction at the second position is a2, at this time the support force of the gas spring is f2. Therefore, at the first position, the vertical component force F1 provided by the gas spring is f1*cos a1; at the second position, the vertical component force F2 provided by the gas spring is f2*cos a2. The second position is compressed shorter than the first position, so f2 is greater than f1, and with the rotation of the gas spring, a2 is greater than a1, cosa2 is less than cosa1, therefore, the vertical component force provided by the second position compared with the first position does not change or changes little, thus avoiding the "pulling heavier and heavier" problem caused by the vertical arrangement of the gas spring.

[0047] In order to meet the hovering of the writing board at any position, |F0cosa-G|≤(Fr+Fe), where F0 is the support force provided by the gas spring, G is the gravity of the writing board and the lifting frame, Fr is the sealing friction force between the cylinder and the piston rod, which is measured when the pressure inside the cylinder is equal to the external pressure, i.e. the friction force measured when the gas inside the gas spring is released, Fe is the friction force between the lifting frame and the fixed frame, which is usually ignored due to its smallness, a is the angle between the gas spring and the vertical direction.

[0048] Fm=Fr-|F0cosa-G|, where Fm is the pushing force of the operator when pushing the writing board, in order to make the operator push and pull more labor-saving, therefore F0cosa-G cannot be 0.

[0049] F0cosa-G≤Fr, or G-F0cosa≤Fr;

[0050] Assuming F0 / G=x, Fr / G=y, then: xGcosa-G≤yG, cosa≤(1+y) / x; or G-xGcosa≤yG, cosa≥(1-y) / x.

[0051] The preset angle range is 15°-50°, and the range of x is 1.2-1.4. Through the cooperation of the coefficient and the inclined arrangement of the gas spring, the hovering of the writing board at any position is realized, and the pushing and pulling of the writing board is more labor-saving.

[0052] The following is described with a specific example:

[0053] Basic parameters of the universal plate: the weight of the writing board is 15 kg, the weight of the lifting frame is 5 kg, and the total weight is 20 kg; the force of the gas spring in the upper position of the writing board is 25 kg; the sealing friction force between the piston rod and the guide sleeve of the gas spring is 2-2.2 kg; the inner diameter of the cylinder body is 20 mm, and the diameter of the piston rod is 10 mm. In this embodiment, the minimum angle of the gas spring (i.e. when the writing board is in the upper position) is 25°, and the maximum angle (i.e. when the writing board is in the lower position) is 42°.

[0054] As shown in Figure 1 , the top end of the support mechanism 3 is rotationally connected with the top frame of the fixed frame 1, and the bottom end is rotationally connected with the side frame 11 of the lifting frame 2; in other embodiments, the top end of the support mechanism 3 can also be rotationally connected with the side frame 11 of the fixed frame 1, and the bottom end can be rotationally connected with the bottom frame of the lifting frame 2.

[0055] These two connection modes change the pivot position of the support mechanism 3 and adjust the range of the inclination angle. Through the flexible connection mode, the support mechanism 3 can adapt to fixed frames 1 and lifting frames 2 of different sizes and shapes, improving the universality and installation convenience of the structure. At the same time, the design of rotational connection ensures that the support mechanism 3 can dynamically adjust the angle during lifting, maintaining the balance of force.

[0056] As shown in Figure 5 , the support mechanism 3 includes a support rod and a fixed seat 32, and the fixed seat 32 is hingedly installed at the top end and the bottom end of the support rod. The fixed seat 32 at the top end is fixedly connected with the lifting frame 2, and the fixed seat 32 at the bottom end is fixedly connected with the fixed frame 1.

[0057] The two ends of the support rod are hingedly connected through the fixed seat 32, and the fixed seat 32 is rigidly connected with the lifting frame 2 and the fixed frame 1 respectively. The hinged design enables the support mechanism 3 to dynamically adjust the angle during lifting, ensuring the balance of the component force F and the gravity G, thereby realizing the stable hovering of the writing board 4. The design of pin shaft cooperating with bearing is adopted at the hinge point, which reduces the rotational friction and ensures the flexibility of the angle adjustment of the support mechanism 3. The installation position of the fixed seat 32 can be adjusted slightly according to the weight distribution of the writing board 4, for example, multiple mounting holes 13 are arranged on the top frame of the fixed frame 1 and / or the side frame 11 of the lifting frame 2 to adapt to gas springs 31 of different specifications.

[0058] The support rod can be selected from a gas spring 31 or a hydraulic damping rod, etc., and the output force is automatically adjusted by the internal pressure. The gas spring 31 generates a reverse thrust by gas compression, and the force value curve matches the gravity change of the lifting frame 2 and the writing board 4. The hydraulic damping rod provides damping by liquid flow resistance. Compared with the hydraulic damping rod, the gas spring 31 scheme is lighter and has no risk of liquid leakage, and is suitable for frequent lifting scenarios; the hydraulic damping rod is suitable for heavy load occasions.

[0059] As shown in Figure 6 , the gas spring 31 includes a cylinder body 311, a piston 312, and a piston rod 313. The piston 312 is installed in the cylinder body 311, the cylinder body 311 is filled with gas and hydraulic oil, an outer sealing ring 314 is installed between the piston rod 313 and the cylinder body 311 to prevent hydraulic oil leakage, and an inner sealing ring 315 is not installed between the piston 312 and the cylinder body 311. One end of the piston rod 313 is connected with the piston 312.

[0060] The gas spring 31 of the embodiment Figure 6 (right side) compared with the conventional gas spring Figure 6 (left side), removes the inner sealing ring 315 between the piston 312 and the cylinder body 311, reduces the abnormal noise generated when the piston moves, and reduces the movement resistance of the piston 312, so that the lifting operation is smoother.

[0061] As shown in Figure 1 , the cylinder body 311 is rotatably connected with the lifting frame 2, and the piston rod 313 is rotatably connected with the fixed frame 1. In other embodiments, the cylinder body 311 can be rotatably connected with the fixed frame 1, and the piston rod 313 can be rotatably connected with the lifting frame 2.

[0062] Both installation methods can adapt to angle changes through rotary connection to ensure the balance of the component force F and the gravity G, so as to realize the stable hovering of the writing board 4.

[0063] It should be understood that the maximum length of the gas spring should be able to meet the requirement of lifting the writing board to the highest position, and the minimum length of the gas spring should be able to meet the requirement of lowering the writing board to the lowest position, so as to ensure that the gas spring still has enough stroke space when the writing board moves to the top and the bottom, and avoid that the length of the gas spring hinders the extreme position of the writing board.

[0064] As shown in Figure 3 , the fixed frame 1 includes left and right side frames 11 and upper and lower bending plates 14. The bending plate 14 includes a horizontal plate and a vertical plate. The horizontal plate is provided with a mounting hole 13 for fixation. The vertical plate is provided with an adjusting hole 15. The adjusting hole 15 is a horizontally arranged long slot. The bending plate 14 is installed on the side frame 11 through the long slot.

[0065] The long hole is arranged to adjust the relative position of the bending plate 14 and the side frame 11. When the installation base (wall surface) is uneven, the relative position of the side frame 11 and the bending plate 14 can be adjusted through the long holes on both sides to eliminate the frame distortion caused by the uneven wall surface, so that the side frames 11 on both sides are located on the same vertical plane, thereby avoiding the influence of the uneven installation base on the lifting balance state of the writing board 4. In addition, when multiple writing boards 4 are used together, the positions of the side frames 11 and the bending plates 14 can be adjusted through the long holes to align all the writing boards 4, and the overall effect is more neat.

[0066] As shown in Figure 4 , the back of the lifting frame 2 is provided with a lifting guide groove 21, and the front of the side frame 11 is provided with a lifting guide wheel set 12. The lifting guide wheel set 12 includes at least two left and right staggered guide wheels, and the lifting guide wheel set 12 slides in the lifting guide groove 21. The lifting guide wheel set 12 adopts double guide wheels staggered left and right, which are respectively embedded in the two side recessed tracks of the lifting guide groove 21. This design forms double guide constraints to prevent the lifting frame 2 from shaking.

[0067] Embodiment 2

[0068] This embodiment provides a universal plate, as shown in Figure 8 , including a writing board 4 and a writing board 4 lifting structure as described in embodiment 1, as shown in Figure 9 , the back of the writing board 4 is provided with a horizontal movement guide groove 41, and the front of the lifting frame 2 is provided with a horizontal movement guide wheel set 42. The horizontal movement guide wheel set 42 includes at least two guide wheels staggered up and down, and the horizontal movement guide wheel set 42 slides in the horizontal movement guide groove 41.

[0069] When the writing board 4 needs to move horizontally, the user applies a horizontal pushing force, and the guide wheels roll along the guide groove to achieve smooth left and right movement of the writing board 4. The guide wheels staggered up and down form double limiting to prevent the writing board 4 from shaking. Through the cooperation of the horizontal movement guide groove 41 and the horizontal movement guide wheel set 42, the writing board 4 can realize horizontal movement, further improving the flexibility and convenience of use, and being suitable for scenarios that require writing at different positions, such as large-scale teaching or conference environment.

[0070] Embodiment 3

[0071] This embodiment provides a combination plate, including at least two universal plates as described in embodiment 2, and all the universal plates are arranged in the same vertical plane. The design of the combination plate can significantly expand the writing area to meet the needs of multiple people writing at the same time. At the same time, all the universal plates are arranged in the same vertical plane to ensure the stability and aesthetics of the overall structure.

[0072] Embodiment 4

[0073] This embodiment provides a multifunctional plate, as shown inFigure 10 As shown, the multifunctional board comprises a display screen 5 and a universal board as described in Embodiment 2, which is arranged on the left and right sides of the display screen 5; or the universal board is arranged on the upper and lower sides of the display screen 5.

[0074] The multifunctional board combines the display screen 5 and the universal board, which can be arranged on the left and right sides or the upper and lower sides of the display screen 5, and the writing board 4 can be slidably covered or unfolded, so as to facilitate switching between the writing and the electronic display area. The design of the multifunctional board integrates the writing and display functions, thereby improving the utilization rate of the equipment and the space utilization rate. Meanwhile, the mobility of the universal board ensures that the positions of the writing and display areas can be flexibly adjusted in different scenarios, thereby meeting the multimedia teaching or conference requirements.

[0075] Although the specific embodiments of the utility model have been described in combination with the drawings, it is not a limitation on the protection scope of the utility model, and those skilled in the art should understand that various modifications or deformations made by those skilled in the art on the basis of the technical scheme of the utility model without creative labor are still within the protection scope of the utility model.

Claims

1. A writing board lifting structure, characterized in that, include: Fixed frame, support mechanism and lifting frame; The fixed frame is fixedly installed, and the lifting frame is used to install the writing board. The lifting frame is slidably installed on the fixed frame and can move up and down relative to the fixed frame. The axis of the support mechanism is within a preset angle range with the horizontal plane. The top end of the support mechanism is rotatably connected to the fixed frame, and the bottom end of the support mechanism is rotatably connected to the lifting frame. The resistance of the fixed frame to the lifting frame enables the lifting frame to be suspended at any position in the vertical direction.

2. The writing board lifting structure as described in claim 1, characterized in that, The preset angle range is 15°-50°.

3. The writing board lifting structure as described in claim 1, characterized in that, Let F0 / G = x, where F0 is the supporting force provided by the gas spring, G is the total weight of the writing board and the lifting frame, and x ranges from 1.2 to 1.

4.

4. The writing board lifting structure as described in claim 1, characterized in that, The top end of the support mechanism is rotatably connected to the top frame of the fixed frame, and the bottom end is rotatably connected to the side frame of the lifting frame. Alternatively, the top end of the support mechanism is rotatably connected to the side frame of the fixed frame, and the bottom end is rotatably connected to the bottom frame of the lifting frame.

5. The writing board lifting structure as described in claim 4, characterized in that, The support mechanism includes a support rod and a fixed seat. The fixed seat is hinged to the top and bottom of the support rod. The fixed seat at the top is fixedly connected to the lifting frame, and the fixed seat at the bottom is fixedly connected to the fixed frame.

6. The writing board lifting structure as described in claim 5, characterized in that, The hinge point between the support rod and the fixed seat is installed using a pin-shaft and bearing assembly.

7. The writing board lifting structure as described in claim 1, characterized in that, The support mechanism includes a support rod, which is a gas spring or a hydraulic damping rod.

8. The writing board lifting structure as described in claim 7, characterized in that, The gas spring includes a cylinder, a piston, and a piston rod. The cylinder is filled with gas, the piston is installed in the cylinder, and no inner sealing ring is installed between the piston and the cylinder. One end of the piston rod is connected to the piston.

9. The writing board lifting structure as described in claim 8, characterized in that, The cylinder body is rotatably connected to the lifting frame, and the piston rod is rotatably connected to the fixed frame; Alternatively, the cylinder body is rotatably connected to the fixed frame, and the piston rod is rotatably connected to the lifting frame.

10. The writing board lifting structure as described in claim 1, characterized in that, The fixing frame includes side frames on the left and right sides and bent plates at the top and bottom. The bent plates include horizontal plates and vertical plates. The horizontal plates have mounting holes for fixing, and the vertical plates have adjustment holes. The adjustment holes are horizontally arranged elongated holes, and the bent plates are installed on the side frames through the elongated holes.

11. The writing board lifting structure as described in claim 10, characterized in that, The lifting frame has a lifting guide groove on its back and a lifting guide wheel assembly is installed on the front of the side frame. The lifting guide wheel assembly includes at least two guide wheels arranged alternately on the left and right sides, and the lifting guide wheel assembly slides in the lifting guide groove.

12. A universal joint, characterized in that, The invention includes a writing board and a writing board lifting structure as described in any one of claims 1-11, wherein a transverse guide groove is provided on the back of the writing board, and a transverse guide wheel assembly is provided on the front of the lifting frame, the transverse guide wheel assembly including at least two guide wheels arranged vertically and horizontally, the transverse guide wheel assembly sliding in the transverse guide groove.

13. A composite panel, characterized in that, It includes at least two universal joints as described in claim 12, all of which are arranged in the same vertical plane.

14. A multi-functional board, characterized in that, The device includes a display screen and a universal joint as described in claim 12, wherein the universal joint is located on the left and right sides of the display screen; or, the universal joint is located on the top and bottom sides of the display screen.

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