Multi-limit obtuse angle push-pull blackboard

Abstract

The utility model belongs to the technical field of education equipment, provide a kind of multiple limiting obtuse angle push-pull blackboard, the multiple limiting obtuse angle push-pull blackboard includes frame, push-pull plate, angle-changing plate, drive assembly, front limit sensor, rear limit sensor and middle limit sensor.The multiple limiting obtuse angle push-pull blackboard provided by the utility model, by setting rear limit sensor and middle limit sensor, and both are located in the height direction of angle-changing plate and away from the one end of drive assembly, when angle-changing plate rotates to abut with rear limit sensor or middle limit sensor, drive assembly and corresponding limit sensor respectively form support from different height positions of angle-changing plate, form multiple-point stable support structure, avoid the shaking of angle-changing plate when writing caused by only single side support in prior art, significantly improve use experience.

Description

Technical Field

[0001] This utility model belongs to the field of educational equipment technology, specifically relating to a multi-position obtuse angle push-pull blackboard. Background Technology

[0002] The obtuse-angled push-pull blackboard is a teaching device that combines mechanical innovation with safe design. Primarily used in educational settings, it is particularly suitable for classrooms where frequent switching between traditional blackboard writing and modern multimedia teaching is required. Its core features lie in its obtuse-angled structure, which optimizes space utilization and enhances safety, while its automated drive system enables convenient operation.

[0003] The adjustable angle panels on both sides of the blackboard feature an obtuse angle design (typically greater than 90 degrees) that slopes backward from the outside to the inside. When the sliding panel moves to the sides, the adjustable angle panels automatically adjust their angle via a hinge structure, avoiding the risk of pinching fingers and ensuring that the sliding panel is completely hidden behind the adjustable angle panels, maximizing the use of wall space. This design eliminates the need for manual flipping of the adjustable angle panels during opening and closing; the operation is automated through a push-pull assembly or a linear drive system, significantly improving efficiency.

[0004] However, the power output of the drive component of existing obtuse angle push-pull blackboards is usually only connected to the upper or lower part of the angle plate. As a result, after the angle plate is rotated into place, it can only provide support for one side of the angle plate. This causes the angle plate to wobble within a certain range when writing on it, affecting the user experience. Utility Model Content

[0005] This utility model provides a multi-limit obtuse angle push-pull blackboard, which aims to solve the technical problem that in existing multi-limit obtuse angle push-pull blackboards, after the push-pull plate moves to the rear of the angle plate, it is usually suspended between the push-pull plate and the angle plate, causing the angle plate to wobble within a certain range when writing on the angle plate.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A multi-position obtuse angle push-pull blackboard is provided, comprising a frame, a push-pull plate, a variable angle plate, and a drive assembly. The push-pull plate is slidably engaged with the frame, the variable angle plate is rotatably engaged with the frame, and the power output end of the drive assembly is connected to the variable angle plate to drive the variable angle plate to rotate. The blackboard also includes: A front limit sensor is located on the front side of the angle plate, fixedly connected to the frame, and protrudes from the frame. When the angle plate abuts against the front limit sensor, the drive assembly stops outputting power. A rear limit sensor is located on the rear side of the angle plate, at the end away from the drive assembly in the height direction. The rear limit sensor is fixedly connected to the frame and protrudes from the frame. When the angle plate abuts against the rear limit sensor, the drive assembly stops outputting power. The angle plate and the drive assembly simultaneously support the angle plate. A middle limit sensor is fixedly connected to the front side of the push-pull plate, at the end away from the drive assembly in the height direction. After the push-pull plate slides to the rear side of the angle plate, the middle limit sensor is located on the movement trajectory of the angle plate. When the angle plate abuts against the middle limit sensor, the drive assembly stops outputting power. The middle limit sensor and the drive assembly simultaneously support the angle plate. When the push-pull plate slides to the rear side of the angle plate, the angle plate rotates to the side where the push-pull plate is located and comes into contact with the middle limit sensor.

[0007] In one possible implementation of the multi-limit obtuse angle push-pull blackboard provided by this utility model, the front limit sensor, the rear limit sensor and the middle limit sensor are contact switches, pressure switches or micro switches.

[0008] In one possible implementation of the multi-limit obtuse angle push-pull blackboard provided by this utility model, the frame includes an upper frame, a lower frame, and two side frames. The upper frame is parallel and spaced above the lower frame, and the two side frames are located at both ends of the upper frame and connected to the two ends of the upper frame and the lower frame to form a rectangular frame structure.

[0009] In one possible implementation of the multi-limit obtuse angle push-pull blackboard provided by this utility model, the push-pull plate is slidably engaged with the upper frame and the lower frame, and one end of the variable angle plate is rotatably engaged with one end of the upper frame and the lower frame.

[0010] In one possible implementation of the multi-limit obtuse angle push-pull blackboard provided by this utility model, the front limit sensor and the rear limit sensor are disposed on the upper frame or the lower frame.

[0011] In one possible implementation of the multi-limit obtuse angle push-pull blackboard provided by this utility model, the front limit sensor and the rear limit sensor are disposed on the upper frame, and the driving component is disposed on the lower frame.

[0012] In one possible implementation of the multi-position obtuse angle push-pull blackboard provided by this utility model, the driving component includes: A drive plate is connected to the rear side of the angle plate, and a guide groove is provided on the drive plate; A guide frame is fixedly connected to the frame, and a drive block and a screw are provided on its upper side. The drive block is slidably mounted on the guide frame. The screw is set at an angle to the guide groove, and the screw passes through the drive block and is threadedly engaged with the drive block. The motor assembly is fixedly connected to the frame, and its power output end is connected to the screw to drive the screw to rotate; and A drive column, connected to the drive block and passing through the guide groove, is adapted to move within the guide groove along the extension direction of the screw, thereby driving the variable angle plate to rotate.

[0013] The beneficial effects of the multi-limit obtuse angle push-pull blackboard provided by this utility model are as follows: Compared with the prior art, the multi-limit obtuse angle push-pull blackboard provided by this utility model has a front limit sensor to ensure that the angle plate stops accurately and is stably supported in the front working position; a rear limit sensor to ensure that the angle plate is reliably positioned in the rear position without the obstruction of the push-pull plate; and a middle limit sensor to ensure that the angle plate and the push-pull plate are precisely matched and stably stopped when the push-pull plate slides to the rear side of the angle plate. The coordinated action of each limit sensor realizes the accurate positioning and stable support of the angle plate in different working states. By setting a rear limit sensor and a middle limit sensor, both of which are located at the end away from the drive component in the height direction of the angle plate, when the angle plate rotates to abut against the rear limit sensor or the middle limit sensor, the drive component and the corresponding limit sensor support the angle plate from different height positions, forming a multi-point stable support structure. This avoids the shaking of the angle plate during writing caused by only one side support in the prior art, and significantly improves the user experience. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the front view structure of the multi-position obtuse angle push-pull blackboard provided in the embodiment of this utility model; Figure 2 For along Figure 1 Cross-sectional view of line AA in the middle; Figure 3 for Figure 1 Enlarged view of part B in the image; Figure 4 A three-dimensional structural diagram of a multi-position obtuse angle push-pull blackboard provided for an embodiment of this utility model; Figure 5 for Figure 4 Enlarged view of section C in the image; Explanation of reference numerals in the attached figures: 11. Top border; 12. Bottom border; 13. Side border; 21. Sliding panel; 22. Angle panel; 31. Front limit sensor; 32. Middle limit sensor; 33. Rear limit sensor; 34. Connecting bracket; 41. Drive plate; 42. Guide frame; 43. Drive block; 44. Drive column; 45. Screw; 46. ​​Motor assembly. Detailed Implementation

[0015] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0016] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is actually illustrative only and is in no way intended to limit this application or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0017] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0018] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0019] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0020] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, and the spatial relative descriptions used herein will be interpreted accordingly.

[0021] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0022] Please refer to the following: Figures 1 to 5 The present invention provides a multi-position obtuse angle push-pull blackboard. The multi-position obtuse angle push-pull blackboard includes a frame, a push-pull plate 21, a variable angle plate 22, a drive assembly, a front limit sensor 31, a rear limit sensor 33, and a middle limit sensor 32. The push-pull plate 21 is slidably engaged with the frame, and the variable angle plate 22 is rotatably engaged with the frame. The power output end of the drive assembly is connected to the variable angle plate 22 to drive the variable angle plate 22 to rotate. Figure 2 and Figure 4 As shown, the front limit sensor 31 is located on the front side of the variable angle plate 22, fixedly connected to the frame, and protrudes from the frame. When the variable angle plate 22 abuts against the front limit sensor 31, the drive assembly stops outputting power; Figure 2As shown, the rear limit sensor 33 is located on the rear side of the angle plate 22, at the end furthest from the drive assembly in the height direction. The rear limit sensor 33 is fixedly connected to the frame and protrudes from the frame. When the angle plate 22 abuts against the rear limit sensor 33, the drive assembly stops outputting power, and the angle plate 22 and the drive assembly simultaneously support the angle plate 22. Figure 3 As shown, the middle limit sensor 32 is fixedly connected to the front side of the push-pull plate 21 and the end away from the drive assembly in the height direction. After the push-pull plate 21 slides to the rear side of the variable angle plate 22, the middle limit sensor 32 is located on the movement trajectory of the variable angle plate 22. When the variable angle plate 22 abuts against the middle limit sensor 32, the drive assembly stops outputting power. The middle limit sensor 32 and the drive assembly simultaneously support the variable angle plate 22.

[0023] When the push-pull plate 21 slides to the rear side of the variable angle plate 22, the variable angle plate 22 rotates toward the side where the push-pull plate 21 is located and abuts against the middle limit sensor 32.

[0024] It should be noted that when the push-pull plate 21 needs to slide to the rear of the angle plate 22, the angle plate 22 first rotates outward to make room for the push-pull plate 21; then the push-pull plate 21 slides to the rear of the angle plate 22. At this time, there is a certain gap between the angle plate 22 and the push-pull plate 21. Therefore, after the push-pull plate 21 moves into position, the drive assembly drives the angle plate 22 to rotate to the side of the push-pull plate 21 until the angle plate 22 abuts against the middle limit sensor 32 on the push-pull plate 21. The drive assembly stops outputting power. At this time, the lower side of the angle plate 22 is supported by the drive assembly, and the upper side is supported by the middle limit sensor 32.

[0025] The beneficial effects of the multi-limit obtuse angle push-pull blackboard provided in this embodiment of the present invention are as follows: Compared with the prior art, the multi-limit obtuse angle push-pull blackboard provided in this embodiment of the present invention ensures that the front limit sensor 31 ensures that the angle plate 22 stops accurately and is stably supported in the front working position; the rear limit sensor 33 ensures that the angle plate 22 is reliably positioned in the rear position without the obstruction of the push-pull plate 21; and the middle limit sensor 32 ensures that the angle plate 22 and the push-pull plate 21 are precisely matched and stably stopped when the push-pull plate 21 slides to the rear side of the angle plate 22. The coordinated action of each limit sensor realizes the accurate positioning and stable support of the angle plate 22 in different working states.

[0026] By setting a rear limit sensor 33 and a middle limit sensor 32, both located at the end of the variable angle plate 22 away from the drive component in the height direction, when the variable angle plate 22 rotates to abut against the rear limit sensor 33 or the middle limit sensor 32, the drive component and the corresponding limit sensor support the variable angle plate 22 from different height positions, forming a multi-point stable support structure. This avoids the shaking of the variable angle plate 22 during writing caused by only one side support in the prior art, and significantly improves the user experience.

[0027] Each limit sensor achieves its limit by contacting the angle plate 22 or the push-pull plate 21, which avoids structural collisions or damage caused by excessive rotation of the angle plate 22. At the same time, the stable support structure reduces wear during equipment use, extends the service life of the equipment, and improves the safety and reliability of the overall structure.

[0028] In one specific embodiment of the multi-limit obtuse angle push-pull blackboard provided in this utility model, the front limit sensor 31, the rear limit sensor 33 and the middle limit sensor 32 are contact sensors such as contact switches, pressure switches or micro switches.

[0029] It should be noted that, among these, the contact switch achieves circuit switching through physical contact between the angle plate 22 or the push-pull plate 21; the pressure switch is triggered by a contact pressure threshold signal; and the micro switch completes limit detection by driving the internal spring to move through a small mechanical displacement. All three types of switches are mature mechanical trigger sensors, requiring no complex optical or electromagnetic induction modules, and can withstand a certain amount of pressure, providing good support for the angle plate 22.

[0030] Contact switches are not sensitive to classroom dust and changes in light. Compared with photoelectric sensors, they are better able to adapt to the complex environment of teaching scenarios and reduce the risk of accidental triggering.

[0031] like Figure 1 and Figure 4 As shown in the embodiment of the multi-limit obtuse angle push-pull blackboard provided in this utility model, the frame includes an upper frame 11, a lower frame 12, and two side frames 13. The upper frame 11 is parallel and spaced above the lower frame 12, and the two side frames 13 are located at both ends of the upper frame 11 and connected to both ends of the upper frame 11 and the lower frame 12 to form a rectangular frame structure. The frame material is preferably high-strength aluminum alloy or cold-rolled steel plate, and it is fixed by bolts or welding to ensure the rigidity of the overall structure.

[0032] It should be noted that the rectangular frame distributes the load evenly through the force distribution on its four sides. Compared with an asymmetrical structure, it can more evenly bear the impact force generated by the sliding of the sliding plate 21 and the rotation of the angle plate 22, reducing the risk of deformation after long-term use. The rectangular structure is highly matched with the installation dimensions of the classroom wall, which can maximize the use of wall space, while providing regular movement trajectory constraints for the sliding plate 21 and the angle plate 22.

[0033] The standardized rectangular frame facilitates mass production, and the detachable connection design of the top and bottom borders 12 and the side borders 13 reduces the difficulty of transportation and installation, and improves production efficiency.

[0034] like Figure 1 and Figure 4 As shown in a specific embodiment of the multi-limit obtuse angle push-pull blackboard provided in this utility model, the push-pull plate 21 is slidably engaged with the upper frame 11 and the lower frame 12, and one end of the variable angle plate 22 is rotatably engaged with one end of the upper frame 11 and the lower frame 12. The upper and lower ends of the variable angle plate 22 are rotatably connected to the ends of the upper frame 11 and the lower frame 12 through hinges or bushings, and the rotation axis is parallel to the frame axis, ensuring that the variable angle plate 22 can rotate around the end to adjust the angle. like Figure 2 and Figure 3 As shown in a specific embodiment of the multi-limit obtuse angle push-pull blackboard provided in this utility model, the front limit sensor 31 and the rear limit sensor 33 are disposed on the upper frame 11 or the lower frame 12. Specifically, they can be fixed to the inside of the frame by buckles or threads, and the sensor trigger end faces the rotation trajectory of the angle plate 22 to ensure that the angle plate 22 can accurately abut when it rotates into place.

[0035] It should be noted that the upper and lower frame 12 is directly connected to the rotation axis of the angle plate 22. Installing the sensor here can shorten the detection distance, reduce signal delay, and ensure timely limit response.

[0036] Installing the sensor away from the side frame 13 avoids conflict with the sliding track of the push-pull plate 21, prevents the sensor from being damaged by the push-pull plate 21, and simplifies the internal wiring structure of the frame.

[0037] The rigid connection between the sensor and the frame can withstand the impact force when the angle plate 22 abuts. The load-bearing capacity of the top and bottom frames 12 is better than that of the side frames 13, reducing the risk of sensor loosening. like Figure 1 and Figure 2 As shown in a specific embodiment of the multi-limit obtuse angle push-pull blackboard provided in this utility model, the front limit sensor 31 and the rear limit sensor 33 are disposed on the upper frame 11. The drive assembly is connected to the lower frame 12 and disposed inside the lower frame 12.

[0038] Specifically, the front limit sensor 31 is fixedly connected to the front side of the upper frame 11 via the connecting bracket 34.

[0039] It should be noted that the upper frame 11 is far from the ground, which can reduce interference factors such as dust accumulation and student touch, and reduce the risk of sensor failure due to contamination or accidental touch.

[0040] like Figure 4 and Figure 5 As shown in the embodiment of the multi-limit obtuse angle push-pull blackboard provided in this utility model, the driving assembly includes a driving plate 41, a guide frame 42, a motor assembly 46, and a driving column 44. The driving plate 41 is connected to the rear side of the variable angle plate 22, and a guide groove is provided on the driving plate 41. The guide frame 42 is fixedly connected to the frame, and a driving block 43 and a screw 45 are provided on its upper side. The driving block 43 is slidably disposed on the guide frame 42. The screw 45 is set at an angle to the guide groove, and the screw 45 passes through the driving block 43 and is threadedly engaged with the driving block 43. The motor assembly 46 is fixedly connected to the frame, and its power output end is connected to the screw 45 to drive the screw 45 to rotate. The driving column 44 is connected to the driving block 43 and passes through the guide groove. The driving column 44 is adapted to move in the guide groove along the extension direction of the screw 45 to drive the variable angle plate 22 to rotate.

[0041] It should be noted that the drive plate 41 is rigidly connected to the rear side of the angle plate 22 by bolts or welding, and the guide groove on its surface is an arc-shaped or oblique long groove, the width of which is adapted to the diameter of the drive column 44; the guide frame 42 is fixed to the frame (preferably the lower frame 12 or the side frame 13) by bolts, and the drive block 43 on it slides with the guide frame 42 through a slide rail or slide groove, and can move along the length of the guide frame 42; the screw 45 forms a preset angle with the guide groove, and the two ends of the screw 45 are rotatably connected to the guide frame 42 through bearing seats. It also engages with the internal threaded hole of the drive block 43 to form a screw drive structure; the motor assembly 46 (such as a servo motor or stepper motor) is fixed to the frame, and its output shaft is connected to one end of the screw 45 through a coupling, which can drive the screw 45 to rotate in both directions; the drive column 44 is vertically fixed to the side of the drive block 43, and its end passes through the guide groove and slides in contact with the inner wall of the guide groove. When the drive block 43 moves along the screw 45, the drive column 44 can slide in the guide groove and push the drive plate 41, thereby driving the variable angle plate 22 to rotate around the rotation axis.

[0042] The threaded engagement between the screw 45 and the drive block 43 provides rigid transmission, which can precisely control the displacement of the drive block 43. Combined with the constraint of the guide groove and the drive column 44, it can achieve precise control of the rotation angle of the variable angle plate 22, avoiding positioning errors caused by transmission clearance. At the same time, the self-locking characteristic of the threaded transmission can lock the position of the variable angle plate 22 when the motor stops working, preventing it from shifting due to external forces (such as writing pressure), and significantly improving support stability.

[0043] The lead screw drive structure can efficiently convert the rotational motion of the motor into linear driving force, providing a large push and pull force, adapting to angle plates 22 of different weights, and when the angle plate 22 is subjected to writing pressure, the overall rigid support of the drive component can effectively resist deformation and further reduce shaking.

[0044] In addition, the drive component can also be an electric actuator located on the front side of the angle plate 22, with the electric actuator hinged to the frame and the power output end hinged to the angle plate 22.

[0045] Alternatively, the driving component may be a hydraulic rod with its two ends hinged to the frame and the angle plate 22, respectively, etc., a mechanism capable of driving the angle plate 22 to rotate.

[0046] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A multi-position obtuse angle push-pull blackboard, comprising a frame, a push-pull plate (21), a variable angle plate (22), and a driving assembly, wherein the push-pull plate (21) is slidably engaged with the frame, the variable angle plate (22) is rotatably engaged with the frame, and the power output end of the driving assembly is connected to the variable angle plate (22) to drive the variable angle plate (22) to rotate, characterized in that, Also includes: A front limit sensor (31) is located on the front side of the variable angle plate (22), fixedly connected to the frame, and protrudes from the frame. When the variable angle plate (22) abuts against the front limit sensor (31), the drive assembly stops outputting power. The rear limit sensor (33) is located on the rear side of the variable angle plate (22) at the end away from the drive assembly in the height direction. The rear limit sensor (33) is fixedly connected to the frame and protrudes from the frame. When the variable angle plate (22) abuts against the rear limit sensor (33), the drive assembly stops outputting power. The variable angle plate (22) and the drive assembly support the variable angle plate (22) simultaneously. A middle limit sensor (32) is fixedly connected to the front side of the push-pull plate (21) at one end away from the drive assembly in the height direction. After the push-pull plate (21) slides to the rear side of the variable angle plate (22), the middle limit sensor (32) is located on the movement trajectory of the variable angle plate (22). When the variable angle plate (22) abuts against the middle limit sensor (32), the drive assembly stops outputting power. The middle limit sensor (32) and the drive assembly simultaneously support the variable angle plate (22). When the push-pull plate (21) slides to the rear side of the variable angle plate (22), the variable angle plate (22) rotates to the side where the push-pull plate (21) is located and abuts against the middle limit sensor (32).

2. The multi-position obtuse angle push-pull blackboard as described in claim 1, characterized in that, The front limit sensor (31), the rear limit sensor (33), and the middle limit sensor (32) are contact switches, pressure switches, or micro switches.

3. The multi-position obtuse angle push-pull blackboard as described in claim 1, characterized in that, The frame includes an upper frame (11), a lower frame (12) and two side frames (13). The upper frame (11) is arranged parallel to each other on the upper side of the lower frame (12). The two side frames (13) are arranged at both ends of the upper frame (11) and connected to both ends of the upper frame (11) and the lower frame (12) to form a rectangular frame structure.

4. The multi-position obtuse angle push-pull blackboard as described in claim 3, characterized in that, The push-pull plate (21) is slidably engaged with the upper frame (11) and the lower frame (12), and one end of the variable angle plate (22) is rotatably engaged with one end of the upper frame (11) and the lower frame (12).

5. The multi-position obtuse angle push-pull blackboard as described in claim 4, characterized in that, The front limit sensor (31) and the rear limit sensor (33) are located on the upper frame (11) or the lower frame (12).

6. The multi-position obtuse angle push-pull blackboard as described in claim 5, characterized in that, The front limit sensor (31) and the rear limit sensor (33) are located on the upper frame (11), and the driving component is located on the lower frame (12).

7. The multi-position obtuse angle push-pull blackboard as described in any one of claims 1-6, characterized in that, The driving component includes: A drive plate (41) is connected to the rear side of the variable angle plate (22), and a guide groove is provided on the drive plate (41); The guide frame (42) is fixedly connected to the frame, and a drive block (43) and a screw (45) are provided on the upper side. The drive block (43) is slidably disposed on the guide frame (42). The screw (45) is set at an angle to the guide groove, and the screw (45) passes through the drive block (43) and is threadedly engaged with the drive block (43). The motor assembly (46) is fixedly connected to the frame, and its power output end is connected to the screw (45) to drive the screw (45) to rotate; and A drive column (44) is connected to the drive block (43) and passes through the guide groove. The drive column (44) is adapted to move in the guide groove along the extension direction of the screw (45) to drive the variable angle plate (22) to rotate.

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