A protective cover for an LED display screen

By integrating the storage components, guide plates, and capillary ropes for the cleaning fluid, and combining blocking and sealing components to control the fluid supply, the problem of cumbersome cleaning and maintenance of LED displays is solved, achieving efficient integrated cleaning and convenient temporary writing.

CN122201138APending Publication Date: 2026-06-12SHENZHEN SANBUM OPTOELECTRONICS CO LTD

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
SHENZHEN SANBUM OPTOELECTRONICS CO LTD
Filing Date
2026-05-08
Publication Date
2026-06-12

AI Technical Summary

Technical Problem

The cleaning and maintenance of existing LED displays are cumbersome, making it difficult to achieve integration, and temporary writing and labeling are inconvenient, affecting display efficiency.

Method used

Design a protective cover for an LED display screen, integrating a storage unit, a cleaning unit, and an output unit for storing cleaning fluid. The cleaning fluid is evenly delivered through a guide plate and a capillary rope. The fluid supply is controlled by a blocking component and a sealing component. It also features a whiteboard writing function. A chute and slider structure allows the cleaning sponge block to move, improving cleaning efficiency and convenience.

Benefits of technology

It integrates display screen protection and cleaning, ensuring a uniform and efficient cleaning process, reducing the risk of dry wiping, meeting temporary writing needs, and improving maintenance efficiency and convenience.

✦ Generated by Eureka AI based on patent content.

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Abstract

The present application relates to the technical fields of display screen protection, more particularly, the present application relates to a protective cover for LED display screen, comprising an LED display screen, a protective member capable of being installed on the LED display screen is arranged on the LED display screen, a storage member for storing cleaning liquid is arranged on the protective member, the storage member further comprises a cleaning member capable of cleaning the LED display screen, and an output member capable of delivering the cleaning liquid to the cleaning member is arranged in the storage member, the present application integrates the storage member, the output member and the cleaning member on the protective member of the LED display screen, realizes controllable delivery and uniform distribution of the cleaning liquid, so that the display screen can be quickly cleaned without disassembly and assembly, and the maintenance problems caused by leakage, evaporation of the cleaning liquid and dryness of the cleaning member are reduced, meanwhile, a blocking member is arranged to realize opening or closing control of liquid supply, and the wetness of the cleaning member is maintained through capillary penetration, so that the convenience of continuous use is improved.
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Description

Technical Field

[0001] This invention relates to the field of display screen protection technology, and more specifically, to a protective cover for an LED display screen. Background Technology

[0002] In existing technologies, LED displays in office conference rooms, teaching venues and other settings are exposed to the air for a long time. Dust, oil and fingerprints easily adhere to the screen surface, requiring frequent cleaning. Conventional protective covers / frames are mostly for "shielding or collision protection" and are usually separate from cleaning and maintenance. This results in additional tools and consumables still needed for cleaning, making the maintenance process cumbersome and inefficient.

[0003] Current cleaning methods often use a combination of sprayed cleaning solution and sponges, which has problems such as uneven application of cleaning solution, scratches caused by local dry wiping, and liquid drips that contaminate the frame and equipment. In addition, the wiping parts are prone to drying out and need to be re-wetted before the next use, which affects continuous maintenance. At the same time, "temporary writing and annotation and presentation of key points" are often required in meetings. The traditional approach is to use an additional whiteboard or stickers, which has problems such as taking up space, inconvenience in switching, easy loss of whiteboard erasers and untimely cleaning, making it difficult to form an integrated display and maintenance experience with the display screen.

[0004] Therefore, we propose a protective cover for LED displays to solve the above problems. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a protective cover for an LED display screen to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a protective cover for an LED display screen, comprising an LED display screen: a protective component that can be installed on the LED display screen; a storage component for storing cleaning fluid on the protective component, and the storage component further comprising a cleaning component capable of cleaning the LED display screen, the storage component comprising an output component capable of conveying the cleaning fluid to the cleaning component; a blocking component installed on the protective component; and a writing component capable of writing on the protective component.

[0007] In a preferred embodiment, the protective component includes a protective frame disposed on the LED display screen. The protective frame is fixed to the LED display screen by two fixing screws. The protective frame is provided with two symmetrical sliding grooves, and a slider is slidably connected in each of the two sliding grooves. A vertical block is disposed between the two sliders on one side of the LED display screen, and a handle for easy pulling is fixedly connected to the side wall of the vertical block.

[0008] In a preferred embodiment, the storage component includes a storage box disposed in a vertical block, a threaded sleeve extending above one of the sliders is threadedly connected to the vertical block, a replenishment tank is fixedly connected to the upper end of the threaded sleeve, and a plurality of balls in contact with the protective frame are embedded in the replenishment tank, a cleaning component is connected to the side wall of the vertical block, and an output component extending into the storage box is provided in the cleaning component.

[0009] In a preferred embodiment, the cleaning component includes a connecting block fixedly connected to the side wall of the vertical block, a guide plate fixedly connected to the side wall of the connecting block, a plurality of guide cavities provided in the guide plate, the plurality of guide cavities being connected and arranged through a plurality of first guide channels, a second guide channel being provided at the output end of each of the plurality of guide cavities, a cleaning sponge block fixedly connected to the side wall of the guide plate, and two protective blocks for protecting the cleaning sponge block fixedly connected to the side wall of the guide plate.

[0010] In a preferred embodiment, the output component includes multiple mounting tubes that pass through the guide plate. Each mounting tube has an output tube fixedly connected to its inner sidewall. Each output tube has a protective plate fixedly connected to its inner sidewall. Each protective plate has a permeation hole on its sidewall. A single capillary rope passes through each protective plate. The multiple output tubes extend into the storage box, and the multiple capillary ropes extend into the storage box.

[0011] In a preferred embodiment, the blocking member includes a damping sleeve that extends through another slider. A rotating rod extending below the other slider is rotatably connected in the damping sleeve. The upper end of the rotating rod extends into the storage box, and a rotating disk is fixedly connected to the upper end of the rotating rod. A closing member is fixedly connected to the upper end of the rotating disk.

[0012] In a preferred embodiment, the sealing component includes a sealing plastic plate fixedly connected to the upper end of the rotating disk. The sealing plastic plate is arc-shaped, and the arc angle of the sealing plastic plate is consistent with the arc angle of the storage box. Two sealing rubber strips that contact the storage box are fixedly connected to the side wall of the sealing plastic plate. Both sealing rubber strips have permeable openings on their side walls. Multiple sealing rubber heads that match the output pipe are fixedly connected to the side wall of the sealing plastic plate. Each of the multiple sealing rubber heads has through holes on its side wall.

[0013] In a preferred embodiment, the writing component includes a whiteboard fixedly connected to the side wall of a vertical block. A mounting frame is fixedly connected to the side wall of the protective frame. Two telescopic cylinders are fixedly connected to the inner side wall of the mounting frame. Notably, each telescopic cylinder consists of a telescopic column and a telescopic rod, with a spring fixedly connected to one end of the telescopic rod. Simultaneously, one end of the spring is connected to the inner side wall of the telescopic column. The output ends of the two telescopic cylinders are mounted on the same mounting plate. The side wall of the mounting plate is provided with a slot. Two symmetrical rubber strips are fixedly connected to the inner side wall of the slot. Multiple locking blocks that contact the rubber strips are inserted into the slot. Whiteboard cleaning erasers for cleaning the whiteboard are fixedly connected to the side walls of the multiple locking blocks.

[0014] The technical effects and advantages of this invention are as follows: 1. This invention integrates protection and cleaning by setting a storage component for storing cleaning fluid, a cleaning component for cleaning the display screen, and an output component for delivering the cleaning fluid to the cleaning component on the protective component, thereby improving the efficiency of daily maintenance.

[0015] 2. The present invention distributes the cleaning liquid evenly to the cleaning sponge block through the guide cavity and guide channel of the guide plate, and achieves slow release penetration through the permeation hole and capillary of the output component, thereby keeping the sponge block moderately moist, reducing the risk of dry wiping and improving cleaning consistency.

[0016] 3. The present invention controls the opening or closing of the output pipe by using a blocking component to drive a sealing component, and achieves stable limiting under the action of a damping sleeve. This allows for rapid liquid supply and wetting when needed, reliable sealing and leak prevention when not in use, and the maintenance of a small amount of permeation and moisture retention in the closed state.

[0017] 4. The present invention forms a guiding movement mechanism by means of the sliding groove, slider and vertical block of the protective frame, and the vertical block is driven by the pull handle to move the cleaning sponge block, thereby realizing controlled movement along the screen surface and improving wiping efficiency and consistency.

[0018] 5. This invention achieves rapid liquid replenishment and installation through the connection between the threaded sleeve and the liquid replenishment tank, and sets ball bearings on the liquid replenishment tank to contact the protective frame to reduce frictional resistance, thereby improving the convenience of liquid replenishment and the smoothness of movement.

[0019] 6. This invention provides a writing whiteboard on the side wall of a vertical block, and a telescopic cylinder and spring are installed in the mounting frame to keep the whiteboard cleaning wipe in constant contact with the whiteboard, so that the whiteboard can be wiped synchronously during the movement of the whiteboard. The cleaning wipe is replaceable, thereby meeting the needs of temporary labeling and display and improving cleaning convenience.

[0020] 7. This invention reduces the probability of external forces acting directly on the sponge block and extends the service life of the cleaning component by setting a protective block to protect the cleaning sponge block. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the connection structure of the present invention; Figure 2 This is a side view schematic diagram of the connection structure of the present invention; Figure 3 This is a schematic diagram of the first partial cross-sectional connection structure of the present invention; Figure 4 This is a schematic diagram of the second partial cross-sectional connection structure of the present invention; Figure 5 This is a schematic diagram of a partial connection structure of the present invention; Figure 6 for Figure 5 A side view diagram of the connection structure; Figure 7 This is a schematic diagram of the first partially disassembled connection structure of the present invention; Figure 8 for Figure 7 A partially enlarged schematic diagram of the connection structure at point A in the middle; Figure 9 This is a schematic diagram of the connection structure between the cleaning component and the output component in this invention; Figure 10 This is a schematic diagram of the second partially disassembled connection structure of the present invention; Figure 11 for Figure 10 A magnified schematic diagram of the connection structure at point B in the middle; Figure 12 This is a schematic diagram of the connection structure of the closure component in this invention; Figure 13 This is a schematic diagram of a partial connection structure of the writing component in this invention.

[0022] The attached diagram is labeled: 1 LED display screen; 2. Protective components; 21. Protective frame; 22. Fixing screws; 23. Slide groove; 24. Sliding block; 25. Vertical block; 26. Pull handle; 3 Storage component, 31 Storage box, 32 Threaded sleeve, 33 Liquid replenishment tank, 34 Ball bearing, 35 Cleaning component, 36 Output component; 351 Connecting block, 352 Guide plate, 353 Guide cavity, 354 First guide channel, 355 Second guide channel, 356 Cleaning sponge block, 357 Protective block; 361 Installation tube, 362 Output tube, 363 Protective plate, 364 Permeation hole, 365 Capillary rope; 4. Blocking component; 41. Damping sleeve; 42. Rotating rod; 43. Rotating disk; 44. Sealing component; 441 Sealed plastic sheet, 442 Sealed rubber strip, 443 Permeable opening, 444 Sealed rubber head, 445 Through hole; 5. Writing component, 51. Writing whiteboard, 52. Mounting frame, 53. Telescopic cylinder, 54. Mounting plate, 55. Card slot, 56. Rubber strip, 57. Card block, 58. Whiteboard cleaning wipe. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Reference Figure 1 and Figure 2 A protective cover for an LED display screen includes an LED display screen 1, which is a display screen used in office spaces to facilitate staff to display work content. The LED display screen 1 is existing technology and will not be described in detail here.

[0025] Reference Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 The protective component 2 includes a protective frame 21 installed on the LED display screen 1. The protective frame 21 is fixed to the LED display screen 1 by two fixing screws. The protective frame 21 is provided with two symmetrical sliding grooves 23. A slider 24 is slidably connected in each of the two sliding grooves 23. A vertical block 25 located on one side of the LED display screen 1 is provided between the two sliders 24. A handle 26 for easy pulling is fixedly connected to the side wall of the vertical block 25.

[0026] Reference Figure 7 and Figure 8 The storage component 3 includes a storage box 31 disposed in the vertical block 25. A threaded sleeve 32 extending above one of the sliders 24 is threadedly connected to the vertical block 25. A replenishment tank 33 is fixedly connected to the upper end of the threaded sleeve 32, and a plurality of balls 34 that contact the protective frame 21 are embedded in the replenishment tank 33. A cleaning component 35 is connected to the side wall of the vertical block 25, and an output component 36 extending into the storage box 31 is provided in the cleaning component 35.

[0027] Reference Figure 8 and Figure 9The cleaning component 35 includes a connecting block 351 fixedly connected to the side wall of the vertical block 25. A guide plate 352 is fixedly connected to the side wall of the connecting block 351. The guide plate 352 is provided with multiple guide cavities 353. The multiple guide cavities 353 are connected through multiple first guide channels 354. The output end of each of the multiple guide cavities 353 is provided with a second guide channel 355. A cleaning sponge block 356 is fixedly connected to the side wall of the guide plate 352. Two protective blocks 357 for protecting the cleaning sponge block 356 are fixedly connected to the side wall of the guide plate 352.

[0028] Reference Figure 8 and Figure 9 The output component 36 includes multiple mounting tubes 361 that pass through the guide plate 352. Each mounting tube 361 has an output tube 362 fixedly connected to its inner sidewall. Each output tube 362 has a protective plate 363 fixedly connected to its inner sidewall. Each protective plate 363 has a permeation hole 364 on its sidewall. The same capillary rope 365 passes through each protective plate 363. The multiple output tubes 362 extend into the storage box 31, and the multiple capillary ropes 365 extend into the storage box 31.

[0029] Reference Figure 10 and Figure 11 The blocking member 4 includes a damping sleeve 41 that passes through another slider 24. A rotating rod 42 extending to the bottom of the other slider 24 is rotatably connected in the damping sleeve 41. The upper end of the rotating rod 42 extends into the storage box 31, and a rotating disk 43 is fixedly connected to the upper end of the rotating rod 42. A closing member 44 is fixedly connected to the upper end of the rotating disk 43. Reference Figure 11 and Figure 12 The sealing component 44 includes a sealing plastic plate 441 fixedly connected to the upper end of the rotating disk 43. The sealing plastic plate 441 is arc-shaped, and the arc angle of the sealing plastic plate 441 is consistent with the arc angle of the storage box 31. Two sealing rubber strips 442 that are in contact with the storage box 31 are fixedly connected to the side wall of the sealing plastic plate 441. Both sealing rubber strips 442 have permeation openings 443 on their side walls. Multiple sealing rubber heads 444 that match the output pipe 362 are fixedly connected to the side wall of the sealing plastic plate 441. Each of the multiple sealing rubber heads 444 has through holes 445 on its side wall.

[0030] Reference Figure 10 and Figure 13The writing component 5 includes a whiteboard 51 fixedly connected to the side wall of the vertical block 25. A mounting frame 52 is fixedly connected to the side wall of the protective frame 21. Two telescopic cylinders 53 are fixedly connected to the inner side wall of the mounting frame 52. It is worth noting that the telescopic cylinder 53 is composed of a telescopic column and a telescopic rod, and a spring is fixedly connected to one end of the telescopic rod. At the same time, one end of the spring is connected to the inner side wall of the telescopic column. The output ends of the two telescopic cylinders 52 are equipped with the same mounting plate 54. The side wall of the mounting plate 54 is provided with a slot 55. Two symmetrical rubber strips 56 are fixedly connected to the inner side wall of the slot 55. Multiple locking blocks 57 that contact the rubber strips 56 are inserted into the slot 55. Whiteboard cleaning erasers 58 for cleaning the whiteboard 51 are fixedly connected to the side walls of the multiple locking blocks 57.

[0031] Working principle: When the operator needs to use this device, they first add special cleaning fluid for the display screen to the replenishment tank 33. Once the replenishment tank 33 is full, the operator can directly pour the cleaning fluid into the storage box 31. It is particularly noteworthy that both the vertical block 25 and the side wall of the storage box 31 have openings with protective glass, further facilitating the operator's viewing of the cleaning fluid content in the storage box 31. After the storage box 31 is full, the operator can directly rotate the replenishment tank 33 onto one of the sliders 24 via the threaded sleeve 32. This positions the output end of the replenishment tank 33 above the storage box 31. The slider 24 has a threaded hole that matches the threaded sleeve 32, facilitating the installation of the replenishment tank 33. After the cleaning fluid in the storage box 31 is replenished, the operator can directly rotate the rotating rod 42. Notably, with the assistance of the damping sleeve 41, the rotating rod 42 is limited and will not rotate unless subjected to external force. When the rotating rod 42 rotates, the rotating disk 43 rotates, causing the sealing plastic plate 441 to rotate. This moves the sealing rubber strip 442 away from the output pipe 362, allowing the cleaning fluid to enter the guide plate 352 from the output pipe 362. The guide cavity 353, first guide channel 354, and second guide channel 355 in the guide plate 352 enable the cleaning fluid to quickly cover the cleaning sponge block 356, thus wetting the cleaning sponge block 356. Then, the operator pulls the handle 26, and with the assistance of the slide groove 23 and the slider 24, the vertical block 25 can move normally. It is particularly noteworthy that both slide grooves 23 are provided with openings that communicate with them, which ensures the normal movement of the threaded sleeve 32 and the rotating rod 42. When the vertical block 25 moves, the cleaning sponge block 356 can move with it, further cleaning the LED display screen 1. When the cleaning sponge block 356 moves to the protective frame... After the end of 21, the operator can directly reset the rotating rod 42, which will reset the rotating disk 43 and thus the sealing plastic plate 441. When the sealing plastic plate 441 is reset, the sealing rubber strip 442 will be positioned on both sides of the output pipe 362, and the sealing rubber head 444 will block the output pipe 362. This will reduce the amount of cleaning fluid entering the output pipe 362. However, with the assistance of the penetration opening 443, through hole 445 and capillary rope 365, a small amount of cleaning fluid can gradually penetrate into the cleaning sponge block 356, keeping the cleaning sponge block 356 moist for the operator's next use.

[0032] The whiteboard 51 facilitates writing and presentation of content for staff. When not in use, staff can move the vertical block 25 to move the whiteboard 51 to one side of the protective frame 21. Notably, the protective frame 21 has an opening on its side wall that matches the whiteboard 51, further facilitating its movement. During this movement, the whiteboard cleaning eraser 58 comes into contact with the whiteboard 51 with the assistance of the telescopic cylinder 53, allowing staff to easily wipe it. The spring in the telescopic cylinder 53 ensures the eraser 58 adheres tightly to the whiteboard 51, guaranteeing a thorough cleaning. Staff can then pull the eraser 58, moving the locking block 57 within the slot 55 for easy replacement, thus enhancing the device's practicality and meeting staff needs.

[0033] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change. Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other. In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A protective cover for an LED display screen, comprising an LED display screen (1), characterized in that: The LED display screen (1) is provided with a protective component (2) that can be installed on the LED display screen (1). The protective component (2) is provided with a storage component (3) for storing cleaning fluid, and the storage component (3) also includes a cleaning component (35) capable of cleaning the LED display screen (1). The storage component (3) is provided with an output component (36) capable of delivering cleaning fluid to the cleaning component (35). A blocking element (4) is installed on the protective component (2); The protective component (2) is equipped with a writing component (5) capable of writing.

2. The protective cover for an LED display screen according to claim 1, characterized in that: The protective component (2) includes a protective frame (21) set on the LED display screen (1). The protective frame (21) is fixed to the LED display screen (1) by two fixing screws. The protective frame (21) is provided with two symmetrical sliding grooves (23). Sliding blocks (24) are slidably connected in both sliding grooves (23). A vertical block (25) located on one side of the LED display screen (1) is provided between the two sliding blocks (24). A handle (26) for easy pulling is fixedly connected to the side wall of the vertical block (25).

3. The protective cover for an LED display screen according to claim 2, characterized in that: The storage unit (3) includes a storage box (31) disposed in the vertical block (25). A threaded sleeve (32) extending above one of the sliders (24) is threadedly connected to the vertical block (25). A replenishment tank (33) is fixedly connected to the upper end of the threaded sleeve (32), and a plurality of balls (34) that contact the protective frame (21) are embedded in the replenishment tank (33). A cleaning component (35) is connected to the side wall of the vertical block (25), and an output component (36) extending into the storage box (31) is provided in the cleaning component (35).

4. The protective cover for an LED display screen according to claim 3, characterized in that: The cleaning component (35) includes a connecting block (351) fixedly connected to the side wall of the vertical block (25). A guide plate (352) is fixedly connected to the side wall of the connecting block (351). The guide plate (352) is provided with multiple guide cavities (353). The multiple guide cavities (353) are connected through multiple first guide channels (354). The output end of each of the multiple guide cavities (353) is provided with a second guide channel (355). A cleaning sponge block (356) is fixedly connected to the side wall of the guide plate (352). Two protective blocks (357) for protecting the cleaning sponge block (356) are fixedly connected to the side wall of the guide plate (352).

5. The protective cover for an LED display screen according to claim 4, characterized in that: The output component (36) includes multiple mounting tubes (361) that pass through the guide plate (352). Each mounting tube (361) has an output tube (362) fixedly connected to its inner sidewall. Each output tube (362) has a protective plate (363) fixedly connected to its inner sidewall. Each protective plate (363) has a permeation hole (364) on its sidewall. The same capillary rope (365) passes through each of the protective plates (363). Each output tube (362) extends into the storage box (31), and each capillary rope (365) extends into the storage box (31).

6. The protective cover for an LED display screen according to claim 5, characterized in that: The blocking member (4) includes a damping sleeve (41) that passes through another slider (24). A rotating rod (42) extending to the bottom of the other slider (24) is rotatably connected in the damping sleeve (41). The upper end of the rotating rod (42) extends into the storage box (31), and a rotating disk (43) is fixedly connected to the upper end of the rotating rod (42). A closing member (44) is fixedly connected to the upper end of the rotating disk (43).

7. A protective cover for an LED display screen according to claim 6, characterized in that: The sealing component (44) includes a sealing plastic plate (441) fixedly connected to the upper end of the rotating disk (43). The sealing plastic plate (441) is arc-shaped, and the arc angle of the sealing plastic plate (441) is consistent with the arc angle of the storage box (31). Two sealing rubber strips (442) that are in contact with the storage box (31) are fixedly connected to the side wall of the sealing plastic plate (441). Both sealing rubber strips (442) have permeation openings (443) on their side walls. Multiple sealing rubber heads (444) that match the output pipe (362) are fixedly connected to the side wall of the sealing plastic plate (441). Multiple sealing rubber heads (444) have through holes (445) on their side walls.

8. The protective cover for an LED display screen according to claim 7, characterized in that: The writing component (5) includes a writing whiteboard (51) fixedly connected to the side wall of the vertical block (25). A mounting frame (52) is fixedly connected to the side wall of the protective frame (21). Two telescopic cylinders (53) are fixedly connected to the inner side wall of the mounting frame (52). It is worth noting that the telescopic cylinder (53) is composed of a telescopic column and a telescopic rod. A spring is fixedly connected to one end of the telescopic rod, and one end of the spring is connected to the inner side wall of the telescopic column. The output ends of the two telescopic cylinders (52) are equipped with the same mounting plate (54). A slot (55) is provided on the side wall of the mounting plate (54). Two symmetrical rubber strips (56) are fixedly connected to the inner side wall of the slot (55). Multiple blocks (57) that contact the rubber strips (56) are inserted into the slot (55). Whiteboard cleaning erasers (58) for cleaning the writing whiteboard (51) are fixedly connected to the side wall of the multiple blocks (57).