An automatic stacking device for seedling trays

Abstract

This invention discloses an automatic stacking device for seedling trays, belonging to the technical field of seedling equipment. It includes a conveying mechanism for transporting seedling trays, a limiting mechanism at one end of the conveying mechanism, and a stacking mechanism at the end of the conveying mechanism near the limiting mechanism. The stacking mechanism includes a connecting frame slidably connected to the outside of the conveying mechanism, positioned above the limiting mechanism when stacking seedling trays. A first fixing part is symmetrically arranged inside the connecting frame, adapted to the seedling tray. A second fixing part is symmetrically arranged at the top of the connecting frame, including a support plate for supporting the seedling tray. A lifting mechanism is located below the limiting mechanism. This invention, through the coordinated operation of the conveying mechanism, limiting mechanism, stacking mechanism, and lifting mechanism, achieves full automation of the entire process from conveying to stacking seedling trays, significantly reducing manual labor intensity.

Description

Technical Field

[0001] This invention belongs to the technical field of seedling raising equipment, and in particular relates to an automatic stacking device for seedling trays. Background Technology

[0002] Rice seedling raising is a crucial step in rice cultivation. Seedling trays, as the essential carriers of the seedlings, need to be stacked after raising the seedlings to facilitate subsequent transportation, storage, and transplanting. Currently, the stacking of rice seedling trays mainly relies on manual operation or semi-automated equipment, which presents the following prominent problems: (1) High labor intensity and low efficiency. Manual stacking requires operators to repeatedly move and align seedling trays. Each stacking cycle takes a long time and the daily processing capacity is limited. Especially in large-scale seedling bases, the labor cost is high.

[0003] (2) Unstable stacking quality. The accuracy of manual alignment is affected by the operator's experience and fatigue level, which can easily lead to problems such as seedling trays shifting, tilting, and uneven stacking. This results in uneven stress on the bottom seedling trays, causing deformation and damage, which affects the survival rate of seedlings. Summary of the Invention

[0004] The purpose of this invention is to provide an automatic stacking device for seedling trays to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the present invention provides the following solution: The present invention provides an automatic stacking device for seedling trays, including a conveying mechanism for conveying seedling trays, a limiting mechanism at one end of the conveying mechanism, a stacking mechanism at the end of the conveying mechanism near the limiting mechanism, the stacking mechanism including a connecting frame slidably connected to the outside of the conveying mechanism, the connecting frame being located above the limiting mechanism when stacking the seedling trays, a first fixing part symmetrically provided inside the connecting frame, the first fixing part being adapted to the seedling tray, a second fixing part symmetrically provided at the top of the connecting frame, the second fixing part including a support plate for supporting the seedling tray, and a lifting mechanism provided below the limiting mechanism.

[0006] Optionally, the top of the conveying mechanism is symmetrically provided with a first guide plate, and the limiting mechanism includes a first connecting shaft rotatably connected to the first guide plate. A first connecting plate is fixedly connected to the first connecting shaft, and a first limiting plate is fixedly connected to the top surface of the first connecting plate away from the first connecting shaft. A limiting groove is provided on the side of the first limiting plate near the seedling tray. The limiting groove is adapted to the seedling tray. A first pressure sensor is provided in the limiting groove. A first driving part is drivenly connected to the first connecting shaft, and the first driving part is fixedly connected to the first guide plate.

[0007] Optionally, a first gear is fixedly connected to the top of the first connecting shaft, the first gear is located above the first connecting plate, the first driving part includes a first motor fixedly connected to the top surface of the first guide plate, and a second gear is fixedly connected to the output shaft of the first motor, the second gear meshing with the first gear.

[0008] Optionally, the first fixing part includes a second motor fixedly connected to the inner wall of the connecting frame. The output shaft of the second motor is fixedly connected to a first lead screw. The first lead screw is threadedly connected to a first fixing seat. The two ends of the first fixing seat are respectively provided with first through holes. A guide rod is slidably connected in the first through hole. The guide rod is fixedly connected to the inner wall of the connecting frame. The first fixing seat is provided with a first groove on the side near the seedling tray. The second fixing part is located in the first groove.

[0009] Optionally, the second fixing part includes a first electric telescopic rod fixedly connected to the inner top surface of the connecting frame, a second fixing seat fixedly connected to the bottom of the first electric telescopic rod, a second groove provided at the bottom of the second fixing seat, a support plate hinged in the second groove, the support plate being adapted to the seedling tray, a second motor fixedly connected to the outside of the second groove, and the second motor being drivenly connected to the support plate.

[0010] Optionally, a height detection mechanism is provided at the top of the connecting frame. The height detection mechanism includes a first connecting rod fixed to the top surface of the connecting frame. A limit seat is slidably connected to the bottom of the first connecting rod, and a second pressure sensor is embedded in the bottom surface of the limit seat.

[0011] Optionally, the top surface of the limiting seat is provided with a third groove, the bottom of the first connecting rod is slidably connected in the third groove, the bottom of the first connecting rod is symmetrically fixed with a second connecting plate, the second connecting plate is slidably connected in the third groove, a spring is provided between the top of the second connecting plate and the third groove, and a gap is provided between the second connecting plate and the bottom surface of the third groove.

[0012] Optionally, the lifting mechanism includes a second electric telescopic rod fixedly connected within the conveying mechanism, and a suction cup is fixedly connected to the top surface of the second electric telescopic rod. The suction cup is connected to an air source through a flexible hose.

[0013] Optionally, the conveying mechanism includes a conveyor frame, a conveyor belt is provided inside the conveyor frame, the first guide plate is fixedly connected to the top surface of the conveyor frame, and a second guide plate is fixedly connected to the end of the first guide plate away from the limiting mechanism.

[0014] Optionally, the top surface of the seedling tray is provided with limiting pins at the four corners, and the bottom surface of the seedling tray is provided with limiting holes at the four corners, with the limiting pins and limiting holes on two adjacent seedling trays being compatible.

[0015] This invention discloses the following technical effects: Through the coordinated operation of the conveying mechanism, limiting mechanism, stacking mechanism, and lifting mechanism, the entire process from conveying to stacking of seedling trays is automated, significantly reducing the intensity of manual labor; the connecting frame is slidably connected to the outside of the conveying mechanism, and can move back and forth between the stacking position and the storage position, with a compact structure and small space occupation; the first fixing part and the second fixing part fix the seedling tray from the side and bottom respectively, forming a double fixing method of side clamping bottom support, ensuring that the seedling tray is stable in posture during lifting and transfer, and will not slip or tilt; the lifting mechanism lifts the seedling tray from below, avoiding the deformation of the tray that may be caused by clamping from above, and is particularly suitable for the non-destructive handling of shallow tray-shaped seedling trays; the limiting mechanism accurately positions the seedling trays during stacking, ensuring that the stacking position of each layer of seedling trays is consistent and the stacking is highly neat. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The embodiments of this application and their descriptions are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the automatic stacking and palletizing device for seedling trays of the present invention; Figure 2 This is a schematic diagram of the automatic seedling tray stacking device of the present invention from another angle; Figure 3 for Figure 2 A magnified view of part A in the image; Figure 4 This is a schematic diagram of the palletizing mechanism of the present invention; Figure 5 This is a schematic diagram of the lifting mechanism of the present invention; Figure 6 This is a schematic diagram of the connection structure between the first connecting rod and the limiting seat of the present invention; Figure 7 This is a front view of the second fixing part of the present invention; Figure 8 This is a schematic diagram of the structure of the second fixing part of the present invention.

[0017] Figure label: 1. Connecting frame; 2. Seedling tray; 3. First guide plate; 4. First connecting shaft; 5. First connecting plate; 6. First limiting plate; 7. Limiting groove; 8. First gear; 9. First motor; 10. Second gear; 11. Second motor; 12. First lead screw; 13. First fixed seat; 14. First through hole; 15. Guide rod; 16. First groove; 17. First electric telescopic rod; 18. Second fixed seat; 19. Second groove; 20. Support plate; 21. First connecting rod; 22. Limiting seat; 23. Second pressure sensor; 24. Third groove; 25. Second connecting plate; 26. Spring; 27. Gap; 28. Second electric telescopic rod; 29. ​​Flexible hose; 30. Air source; 31. Conveyor frame; 32. Conveyor belt; 33. Second guide plate; 34. Limiting pin. Detailed Implementation

[0018] 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.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Reference Figures 1 to 8 As shown, this embodiment provides an automatic seedling tray stacking device, including a conveying mechanism for conveying seedling trays 2. One end of the conveying mechanism is provided with a limiting mechanism, and the end of the conveying mechanism near the limiting mechanism is provided with a stacking mechanism. The stacking mechanism includes a connecting frame 1 slidably connected to the outside of the conveying mechanism. When stacking seedling trays 2, the connecting frame 1 is located above the limiting mechanism. A first fixing part is symmetrically provided inside the connecting frame 1. The first fixing part is adapted to the seedling tray 2. A second fixing part is symmetrically provided on the top of the connecting frame 1. The second fixing part includes a support plate 20 for supporting the seedling tray 2. A lifting mechanism is provided below the limiting mechanism.

[0021] The seedling tray 2 is fed in from the far end of the conveying mechanism (the end away from the limiting mechanism) and moves along the conveying mechanism towards the limiting mechanism. When the seedling tray 2 reaches the position of the limiting mechanism, the limiting mechanism limits and fixes the seedling tray 2 in the horizontal and vertical directions to ensure that the seedling tray 2 has an accurate posture when it reaches the stacking position. At this time, the connecting frame 1 in the stacking mechanism is located above the limiting mechanism, and the first fixing part and the second fixing part in the connecting frame 1 are both in standby state. When the system determines that a stacking action is required, the lifting mechanism below the limiting mechanism is activated to lift the seedling tray 2 from below and fix it with suction. Then the limiting mechanism opens to release the seedling tray 2. After the seedling tray 2 is lifted to the preset height, the support plate 20 of the second fixing part opens and descends to support the bottom of the seedling tray 2, and then moves upward to lift the seedling tray 2 to the position of the seedling tray 2 that has been stacked above for stacking. After stacking is completed, the first fixing part is released, and the second fixing part continues to move upward to transfer the bottom seedling tray 2 to the first fixing part for clamping and fixing, completing one layer of stacking. This cycle repeats to achieve automatic stacking of multi-layer seedling trays 2. When the stack reaches a preset number of layers or height, the height detection mechanism senses the pressure signal and controls the connecting frame 1 to move the stacked seedling trays 2 to the predetermined storage position. Then, the connecting frame 1 resets back above the limiting mechanism to continue the next round of stacking.

[0022] Through the coordinated operation of the conveying mechanism, limiting mechanism, stacking mechanism, and lifting mechanism, the entire process of transporting and stacking the seedling tray 2 is automated, significantly reducing the intensity of manual labor. The connecting frame 1 is slidably connected to the outside of the conveying mechanism and can move back and forth between the stacking position and the storage position. It has a compact structure and occupies little space. The first fixing part and the second fixing part fix the seedling tray 2 from the side and the bottom, respectively, forming a double fixing method of side clamping and bottom support, ensuring that the seedling tray 2 is stable in posture during lifting and transfer and will not slip or tilt. The lifting mechanism lifts the seedling tray 2 from below, avoiding the deformation of the tray that may be caused by clamping from above. It is especially suitable for the non-destructive handling of shallow tray-shaped seedling trays 2. The limiting mechanism accurately positions the seedling tray 2 during stacking, ensuring that the stacking position of each layer of seedling trays 2 is consistent and the stacking is highly neat.

[0023] In a further optimized design, a first guide plate 3 is symmetrically provided on the top of the conveying mechanism. The limiting mechanism includes a first connecting shaft 4 rotatably connected to the first guide plate 3. A first connecting plate 5 is fixedly connected to the first connecting shaft 4. A first limiting plate 6 is fixedly connected to the top surface of the first connecting plate 5 away from the first connecting shaft 4. A limiting groove 7 is provided on the side of the first limiting plate 6 near the seedling tray 2. The limiting groove 7 is adapted to the seedling tray 2. A first pressure sensor is provided in the limiting groove 7. A first driving unit is drivenly connected to the first connecting shaft 4. The first driving unit is fixedly connected to the first guide plate 3.

[0024] When the seedling tray 2 moves along the conveying mechanism to the position of the limiting mechanism, it first passes through the first guide plate 3 symmetrically arranged at the top of the conveying mechanism. The first guide plate 3 provides initial lateral guidance for the seedling tray 2. After the seedling tray 2 contacts the first limiting plate 6, the limiting groove 7 on the first limiting plate 6 matches the shape of the seedling tray 2, restricting the seedling tray 2 to a predetermined position. The first pressure sensor in the limiting groove 7 detects the contact pressure between the seedling tray 2 and the limiting groove 7 in real time. When the first pressure sensor detects that the seedling tray 2 has reached the position and the pressure value reaches the preset threshold, it indicates that the seedling tray 2 has been accurately positioned, and the system sends an action command to the lifting mechanism and the stacking mechanism. The first drive unit drives the first connecting shaft 4 to rotate through the transmission relationship. The first connecting shaft 4 drives the first connecting plate 5 and the first limiting plate 6 to rotate around the first connecting shaft 4, so that the first limiting plate 6 moves from the limiting position to the open position, releasing the seedling tray 2. After stacking is completed, the first limiting plate 6 is reset under the drive of the first drive unit, and limits the next seedling tray 2 again.

[0025] The first guide plate 3 provides initial guidance for the seedling tray 2, reducing positional deviation when the seedling tray 2 reaches the limiting mechanism and improving limiting accuracy. The first limiting plate 6 opens and closes via a rotating connection. Compared to a translational limiting mechanism, the rotating opening and closing action is faster, occupies less space, and does not interfere with other components on the conveying mechanism during the opening and closing process. The limiting groove 7 is adapted to the shape of the seedling tray 2, achieving precise positioning of the seedling tray 2 and ensuring that the coordinates of each seedling tray 2 are consistent when it reaches the stacking position, thereby ensuring the neatness of the stacking. The first pressure sensor is set in the limiting groove 7, which can accurately sense whether the seedling tray 2 is in place and the degree of compression when it is in place, providing a reliable arrival signal for the system and avoiding malfunctions that could damage the equipment or cause the seedling tray 2 to fall when it is not in place. The first drive unit is fixedly connected to the first guide plate 3, with a stable structure and reliable transmission. The first connecting shaft 4 is rotatably connected to the first guide plate 3, allowing for flexible rotation and smooth opening and closing of the limiting plate.

[0026] In a further optimized design, a first gear 8 is fixedly connected to the top of the first connecting shaft 4. The first gear 8 is located above the first connecting plate 5. The first driving unit includes a first motor 9 fixedly connected to the top surface of the first guide plate 3. A second gear 10 is fixedly connected to the output shaft of the first motor 9, and the second gear 10 meshes with the first gear 8.

[0027] When the first pressure sensor detects that the seedling tray 2 is in place, the control system (not shown in the figure) sends a start command to the first motor 9 in the first drive unit. The output shaft of the first motor 9 drives the second gear 10 to rotate. The second gear 10 meshes with the first gear 8 fixed to the top of the first connecting shaft 4, transmitting the rotational motion to the first connecting shaft 4. The first connecting shaft 4 rotates around its axis, driving the first connecting plate 5 and the first limiting plate 6 fixed to it to rotate synchronously. The first limiting plate 6 rotates from the vertical limiting position to the horizontal opening position, releasing the seedling tray 2. After the stacking action is completed and the seedling tray 2 is taken away by the lifting mechanism, the first motor 9 rotates in the opposite direction. Through the meshing transmission of the second gear 10 and the first gear 8, it drives the first connecting shaft 4 to rotate in the opposite direction, causing the first limiting plate 6 to reset to the limiting position, waiting for the arrival of the next seedling tray 2. The first gear 8 is located above the first connecting plate 5, avoiding interference of the first connecting plate 5 with the gear transmission and ensuring smooth transmission.

[0028] The system employs a gear-driven transmission method, ensuring precise transmission ratios and high efficiency. The opening and closing angles of the first limiting plate 6 are controllable, and the opening and closing actions are smooth and reliable, without any impact. The first gear 8 is positioned above the first connecting plate 5, rationally arranging the spatial relationship between the transmission components and the limiting plate to avoid motion interference and resulting in a compact structure. The gear transmission has a self-locking characteristic (when the transmission ratio is appropriate), ensuring that even under external disturbances, the first limiting plate 6 will not accidentally open when the seedling tray 2 is in the limited position, thus improving the reliability and safety of the limiting mechanism. The first motor 9 is fixed to the top surface of the first guide plate 3, facilitating easy installation and maintenance. Furthermore, the motor's high position minimizes the risk of collision with the seedling tray 2 or other components.

[0029] In a further optimized design, the first fixing part includes a second motor 11 fixedly connected to the inner wall of the connecting frame 1. The output shaft of the second motor 11 is fixedly connected to a first lead screw 12. The first lead screw 12 is threadedly connected to a first fixing seat 13. The two ends of the first fixing seat 13 are respectively provided with first through holes 14. A guide rod 15 is slidably connected in the first through hole 14. The guide rod 15 is fixedly connected to the inner wall of the connecting frame 1. The first fixing seat 13 is provided with a first groove 16 on the side near the seedling tray 2. The second fixing part is located in the first groove 16.

[0030] When the seedling tray 2 is lifted to the stacking position by the lifting mechanism, and the support plate 20 of the second fixing part supports the bottom of the seedling tray 2 and is ready to move upward, the first fixing part needs to clamp and fix the side of the seedling tray 2 that has been stacked. The second motor 11 starts, and its output shaft drives the first lead screw 12 to rotate. The first lead screw 12 is threadedly connected to the first fixing seat 13. The rotation of the first lead screw 12 is converted into the linear movement of the first fixing seat 13 along the guide rod 15. The guide rod 15 passes through the first through holes 14 at both ends of the first fixing seat 13 and is fixed to the inner wall of the connecting frame 1, providing guidance and support for the movement of the first fixing seat 13 and preventing the first fixing seat 13 from rotating with the first lead screw 12. The first fixing seat 13 moves towards the seedling tray 2 along the guide rod 15. When the first fixing seat 13 approaches the seedling tray 2, the first groove 16 on the first fixing seat 13 is adapted to the side wall of the seedling tray 2, forming a clamp or support on the side of the seedling tray 2. Two sets of first fixing parts are symmetrically distributed inside the connecting frame 1, clamping the seedling tray 2 from both sides simultaneously to ensure uniform clamping force. When it is necessary to release the seedling tray 2, the second motor 11 rotates in the opposite direction, and the first fixing seat 13 retracts along the guide rod 15, releasing the clamping force on the seedling tray 2. The second fixing part is located within the first groove 16, indicating that while the first fixing part clamps the seedling tray 2, the second fixing part (support plate 20) is housed in the first groove 16, without spatial conflict with the first fixing part.

[0031] The screw drive has the advantages of high transmission accuracy and good self-locking. The first fixed seat 13 can precisely control the clamping position and clamping force, and will not loosen due to vibration or external force in the clamping state, ensuring reliable side fixation of the seedling tray 2 during the transfer process. The sliding fit between the guide rod 15 and the first through hole 14 provides a stable linear motion guide for the first fixed seat 13, preventing the first fixed seat 13 from swaying or jamming under the screw drive, and ensuring smooth movement. The design of the first groove 16 not only provides storage space for the second fixed part, but also makes the first fixed part and the second fixed part complementary in structure, resulting in high internal space utilization of the connecting frame 1 and a compact overall structure. The two sets of first fixed parts are symmetrically arranged, clamping from both sides simultaneously, with symmetrical distribution of clamping force, so that the seedling tray 2 is evenly stressed and will not tilt or deform due to clamping from one side. The first fixed part achieves clamping through a motor-driven screw, and the clamping stroke can be adjusted according to the size of the seedling tray 2, making it highly adaptable.

[0032] In a further optimized design, the second fixing part includes a first electric telescopic rod 17 fixedly connected to the inner top surface of the connecting frame 1. A second fixing seat 18 is fixedly connected to the bottom of the first electric telescopic rod 17. A second groove 19 is provided at the bottom of the second fixing seat 18. A support plate 20 is hinged in the second groove 19. The support plate 20 is adapted to the seedling tray 2. A second motor 11 is fixedly connected to the outside of the second groove 19. The second motor 11 is connected to the support plate 20 in a transmission connection.

[0033] When the seedling tray 2 is lifted to a preset height by the lifting mechanism from below, the second fixing part begins to operate; the first electric telescopic rod 17 is activated, and its piston rod extends downward, driving the second fixing seat 18 at the bottom to move downward; when the second fixing seat 18 descends to near the bottom of the seedling tray 2, the support plate 20 in the second groove 19 changes from a vertical state to a horizontal state under the drive of the second motor 11; the support plate 20 contacts the bottom surface of the seedling tray 2, and after the support plate 20 becomes horizontal, it forms a supporting surface, supporting the bottom of the seedling tray 2; at this time, the bottom of the seedling tray 2 is supported by the support plate 20. Then, the first electric telescopic rod 17 retracts, driving the second fixing seat 18 and the support plate 20 to move upward, lifting the seedling tray 2 as a whole. When the seedling tray 2 rises to align with the seedling trays 2 already stacked above, the first fixing part releases (if the first fixing part was already clamped at this time), and the seedling trays 2 are stacked. After stacking, the first electric telescopic rod 17 continues to rise, bringing the bottom seedling tray 2 to the position of the first fixing part. The first fixing seat 13 of the first fixing part extends and clamps the seedling tray 2, completing the interlayer transfer. The tray 20 can rotate relative to the second fixing seat 18 under the drive of the second motor 11. When support is not needed, the second motor 11 keeps the tray 20 in a vertical state to avoid interference with other components.

[0034] The first electric telescopic rod 17 provides the lifting power for the second fixing part, with controllable stroke, enabling precise lifting of the seedling tray 2 to the target height and ensuring accurate stacking. The support plate 20 is adapted to the bottom surface of the seedling tray 2, providing a large support area and even force distribution, avoiding indentations or cracks on the bottom of the tray that may be caused by point or line contact, making it particularly suitable for non-destructive support of the plastic seedling tray 2. The second motor 11 drives the support plate 20 to open and close, with flexible movement and fast response speed. It can automatically control the state of the support plate 20 according to the presence or absence of the seedling tray 2, demonstrating a high degree of intelligence. The design of the second groove 19 is mainly to facilitate the rotation of the support plate 20 without affecting the overall size of the connecting frame 1 and the movement of other components. The second fixing part supports the seedling tray 2 from the bottom, complementing the first fixing part's side clamping, achieving all-round fixation of the seedling tray 2's bottom support and side clamps. During transfer, the seedling tray 2 remains stable and will not slip or overturn.

[0035] To further optimize the design, a height detection mechanism is provided at the top of the connecting frame 1. The height detection mechanism includes a first connecting rod 21 fixed to the top surface of the connecting frame 1. A limit seat 22 is slidably connected to the bottom of the first connecting rod 21. A second pressure sensor 23 is embedded in the bottom surface of the limit seat 22.

[0036] When the seedling trays 2 are stacked, the topmost seedling tray 2 gradually approaches the inner top surface of the connecting frame 1. The first connecting rod 21 is fixed to the inner top surface of the connecting frame 1, and its bottom is slidably connected to a limiting seat 22. Under the action of its own weight and / or the force of the spring 26, the limiting seat 22 is initially in a downward position (closer to the direction of the seedling tray 2). As the stacking height of the seedling trays 2 increases, the top surface of the topmost seedling tray 2 gradually rises, contacts the bottom surface of the limiting seat 22, and applies upward pressure to the limiting seat 22. The second pressure sensor 23 embedded in the bottom surface of the limiting seat 22 detects the pressure value in real time. When the pressure value reaches a preset threshold, it indicates that the stacking height of the seedling trays 2 has reached the preset number of layers or height. After receiving the signal, the control system stops the stacking action and drives the connecting frame 1 to move the stacked seedling trays 2 to the predetermined storage position. After the seedling trays 2 are removed, the limiting seat 22 resets under the action of gravity or the force of the spring 26, waiting for the next round of stacking.

[0037] The height detection mechanism is located inside the top of the connecting frame 1, directly detecting the top surface position of the top seedling tray 2. It offers high detection accuracy and is unaffected by external environmental interference. The second pressure sensor 23 is embedded in the bottom surface of the limiting seat 22, accurately sensing changes in the stacked height of the seedling trays 2. It converts mechanical contact into an electrical signal, providing reliable height feedback to the control system. The height detection mechanism has a simple structure, without complex photoelectric or laser components, resulting in low cost and high reliability. It is suitable for long-term stable operation in the dusty and humid environment of the seedling nursery. The height detection mechanism enables automatic control of the stacking layers, avoiding errors from manual counting and ensuring consistent layer counts in each stack of seedling trays 2, facilitating subsequent management and transportation.

[0038] In a further optimized design, the top surface of the limiting seat 22 is provided with a third groove 24, the bottom of the first connecting rod 21 is slidably connected in the third groove 24, the bottom of the first connecting rod 21 is symmetrically fixed with a second connecting plate 25, the second connecting plate 25 is slidably connected in the third groove 24, a spring 26 is provided between the top of the second connecting plate 25 and the third groove 24, and a gap 27 is provided between the second connecting plate 25 and the bottom surface of the third groove 24.

[0039] The top surface of the limiting seat 22 is provided with a third groove 24, and the bottom of the first connecting rod 21 is slidably connected in the third groove 24, providing guidance for the up-and-down movement of the limiting seat 22. A second connecting plate 25 is symmetrically fixed to the bottom of the first connecting rod 21, and the second connecting plate 25 is also slidably connected in the third groove 24, further enhancing the stability of the limiting seat 22's movement and preventing it from tilting or rotating during its up-and-down movement. A spring 26 is provided between the top of the second connecting plate 25 and the top surface of the third groove 24. The spring 26 provides a downward preload to the limiting seat 22, keeping it in the descending position (detection position) when there is no contact with the seedling tray 2. A gap 27 is provided between the second connecting plate 25 and the bottom surface of the third groove 24. This gap 27 allows the limiting seat 22 sufficient upward travel when subjected to upward pressure from the seedling tray 2, while also preventing direct contact and wear between the second connecting plate 25 and the bottom surface of the third groove 24. When the seedling trays 2 are stacked to a preset height, the bottom surface of the seedling trays 2 contacts the bottom surface of the limiting seat 22 and applies pressure. The limiting seat 22 moves upward against the force of the spring 26, and the second connecting plate 25 slides downward along the third groove 24, stretching the spring 26. The second pressure sensor 23 detects the pressure change and sends a signal. When the seedling trays 2 are removed, the spring 26 resets, pushing the limiting seat 22 back to its initial position.

[0040] The third groove 24 provides a precise guide groove for the first connecting rod 21 and the second connecting plate 25, ensuring that the limiting seat 22 can only move vertically without horizontal offset or rotation, resulting in high detection accuracy. The symmetrically arranged second connecting plate 25 ensures even force distribution and smooth movement of the limiting seat 22, avoiding jamming or uneven wear that might occur with unilateral guidance. The spring 26 provides adjustable preload; by replacing springs 26 with different stiffnesses, the sensitivity of height detection and the trigger pressure threshold can be easily adjusted to adapt to different stacking requirements. The gap 27 between the second connecting plate 25 and the bottom surface of the third groove 24 ensures that the limiting seat 22 has sufficient upward travel to accommodate stacking of seedling trays 2 at different heights, while avoiding rigid contact, reducing wear and noise, and extending the service life of the mechanism. The overall structure uses a purely mechanical detection method, with no electronic components exposed externally, providing good dust and water resistance, making it suitable for the harsh environment of the seedling nursery.

[0041] The scheme is further optimized. The lifting mechanism includes a second electric telescopic rod 28 fixed in the conveying mechanism. A suction cup is fixed to the top surface of the second electric telescopic rod 28. The suction cup is connected to an air source 30 through a flexible hose 29.

[0042] When the first pressure sensor detects that the seedling tray 2 has reached the position of the limiting mechanism, the control system sends an action command to the lifting mechanism. The second electric telescopic rod 28 is activated, and its piston rod extends upward, driving the suction cup on the top surface to move upward. When the suction cup rises to the bottom surface of the seedling tray 2, the suction cup is tightly attached to the bottom surface of the seedling tray 2. The air source 30 supplies air to the suction cup through the flexible hose 29 (or draws air to create negative pressure), causing the suction cup to generate suction force and firmly adsorb the seedling tray 2 onto the suction cup. At this time, the seedling tray 2 is fixed by the suction cup from below, while the sides are still limited by the first limiting plate 6 of the limiting mechanism. Subsequently, the first limiting plate 6 of the limiting mechanism opens under the drive of the first drive unit, releasing the side constraint of the seedling tray 2. The second electric telescopic rod 28 continues to extend upward, lifting the suction cup holding the seedling tray 2 to the preset height (stacking position). During this process, the flexible hose 29 bends and deforms with the extension and retraction of the second electric telescopic rod 28, always maintaining airflow. Once the stacking action is completed and the seedling tray 2 is taken over by the support plate 20 of the second fixed part, the air source 30 stops supplying air (or breaks the vacuum), the suction cup releases the seedling tray 2, and the second electric telescopic rod 28 retracts back to its original position, ready for the next lifting action.

[0043] The suction cup adsorption method enables non-destructive gripping of the seedling tray 2. The adsorption force is evenly distributed on the bottom surface of the seedling tray 2, preventing localized stress concentration that could cause the tray to crack, making it particularly suitable for brittle plastic seedling trays 2. The second electric telescopic rod 28 provides the lifting power and stroke control, enabling precise lifting of the seedling tray 2 to the target height and ensuring accurate stacking. The flexible hose 29 connects the air source 30 and the suction cup, solving the air path connection problem during the lifting mechanism's movement. The hose can freely bend with the extension and retraction of the telescopic rod, without restricting the movement stroke or causing pipeline damage due to rigid pipe connections. The lifting mechanism lifts the seedling tray 2 from below, avoiding the squeezing damage to the edges of the seedling tray 2 that might be caused by gripping from above, and the bottom lifting method is more conducive to the stable handling of shallow tray-shaped seedling trays 2. The suction cup adsorption force can be adjusted via the air source 30 pressure, making it highly adaptable and allowing adjustment of the adsorption force according to different materials and weights of seedling trays 2. The second electric telescopic rod 28 is fixed inside the conveying mechanism, with a stable structure. The lifting force is directly transmitted to the frame of the conveying mechanism, without generating additional overturning torque.

[0044] The scheme is further optimized. The conveying mechanism includes a conveyor frame 31, a conveyor belt 32 is provided inside the conveyor frame 31, a first guide plate 3 is fixedly connected to the top surface of the conveyor frame 31, and a second guide plate 33 is fixedly connected to the end of the first guide plate 3 away from the limiting mechanism.

[0045] The stacking operation of the seedling trays 2 uses a conveyor mechanism as the basic transportation platform. The conveyor frame 31 serves as the main frame of the conveyor mechanism, and its interior contains a conveyor belt 32, which is driven by a drive device (not shown in the figure) to rotate cyclically. The seedling trays 2 are placed on the conveyor belt 32 and moved from the far end (feeding end) to the near end (limiting mechanism end) of the conveyor mechanism by the conveyor belt 32. The first guide plate 3 is fixed to the top surface of the conveyor frame 31, located above the conveyor belt 32, and provides lateral guidance for the seedling trays 2, preventing them from shifting left or right during transport. A second guide plate 33 is fixed to the end of the first guide plate 3 furthest from the limiting mechanism. The second guide plate 33 cooperates with the first guide plate 3 to form a gradually changing guide channel, allowing the seedling trays 2 to gradually transition from a wider feeding area to the precise positioning area at the limiting mechanism, ensuring that the seedling trays 2 reach the limiting position smoothly and accurately. Once the stacking is complete, the stacked seedling trays 2 are moved away from the limiting mechanism position by the connecting frame 1, and the conveyor belt 32 continues to operate, sending in the next seedling tray 2.

[0046] To further optimize the design, limiting pins 34 are provided at the four corners of the top surface of the seedling tray 2, and limiting holes are provided at the four corners of the bottom surface of the seedling tray 2. The limiting pins 34 and limiting holes on two adjacent seedling trays 2 are compatible.

[0047] Each seedling tray 2 has four upward-protruding limiting pins 34 at the four corners of its top surface and four downward-recessed limiting holes at the four corners of its bottom surface. When one seedling tray 2 is stacked on top of another, the limiting holes on the bottom surface of the upper seedling tray 2 correspond one-to-one with the limiting pins 34 on the top surface of the lower seedling tray 2 and are inserted into each other. After the limiting pins 34 are inserted into the limiting holes, precise positioning and fixation between the upper and lower seedling trays 2 are achieved, preventing the upper seedling tray 2 from sliding or rotating in the horizontal direction. During the stacking process, when the support plate 20 of the second fixing part lifts the seedling tray 2 to the position of the existing seedling tray 2 above, the limiting pins 34 automatically insert into the limiting holes, achieving automatic alignment and locking of the seedling trays 2 without the need for an additional alignment mechanism. When it is necessary to dismantle the stack, simply lift the upper seedling tray 2 upwards, and the limiting pins 34 will disengage from the limiting holes.

[0048] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to 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 of this invention.

[0049] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A device for automatic stacking of seedling trays, characterized in that: The device includes a conveying mechanism for conveying seedling trays (2), one end of which is provided with a limiting mechanism, and the end of the conveying mechanism near the limiting mechanism is provided with a stacking mechanism. The stacking mechanism includes a connecting frame (1) slidably connected to the outside of the conveying mechanism. The connecting frame (1) is located above the limiting mechanism when stacking the seedling trays (2). A first fixing part is symmetrically provided inside the connecting frame (1), and the first fixing part is adapted to the seedling trays (2). A second fixing part is symmetrically provided at the top of the connecting frame (1), and the second fixing part includes a support plate (20) for supporting the seedling trays (2). A lifting mechanism is provided below the limiting mechanism.

2. The automatic stacking and stacking device of the seedling raising tray according to claim 1, characterized in that: The top of the conveying mechanism is symmetrically provided with a first guide plate (3). The limiting mechanism includes a first connecting shaft (4) rotatably connected to the first guide plate (3). A first connecting plate (5) is fixedly connected to the first connecting shaft (4). A first limiting plate (6) is fixedly connected to the top surface of the first connecting plate (5) away from the first connecting shaft (4). A limiting groove (7) is provided on the side of the first limiting plate (6) close to the seedling tray (2). The limiting groove (7) is adapted to the seedling tray (2). A first pressure sensor is provided in the limiting groove (7). A first driving part is drivenly connected to the first connecting shaft (4). The first driving part is fixedly connected to the first guide plate (3).

3. The automatic stacking device for the seedling raising tray according to claim 2, characterized in that: A first gear (8) is fixedly connected to the top of the first connecting shaft (4). The first gear (8) is located above the first connecting plate (5). The first driving part includes a first motor (9) fixedly connected to the top surface of the first guide plate (3). A second gear (10) is fixedly connected to the output shaft of the first motor (9). The second gear (10) meshes with the first gear (8).

4. The automatic stacking device for the seedling raising tray according to claim 1, wherein: The first fixing part includes a second motor (11) fixedly connected to the inner wall of the connecting frame (1). The output shaft of the second motor (11) is fixedly connected to a first lead screw (12). The first lead screw (12) is threadedly connected to a first fixing seat (13). The two ends of the first fixing seat (13) are respectively provided with first through holes (14). A guide rod (15) is slidably connected in the first through hole (14). The guide rod (15) is fixedly connected to the inner wall of the connecting frame (1). The first fixing seat (13) is provided with a first groove (16) on the side near the seedling tray (2). The second fixing part is located in the first groove (16).

5. The automatic stacking and stacking device for the seedling raising tray according to claim 4, characterized in that: The second fixing part includes a first electric telescopic rod (17) fixedly connected to the inner top surface of the connecting frame (1). A second fixing seat (18) is fixedly connected to the bottom of the first electric telescopic rod (17). A second groove (19) is provided at the bottom of the second fixing seat (18). The tray (20) is hinged in the second groove (19). The tray (20) is adapted to the seedling tray (2). A second motor (11) is fixedly connected to the outside of the second groove (19). The second motor (11) is connected to the tray (20) in a transmission connection.

6. The automatic stacking device for the seedling raising tray according to claim 1, wherein: The connecting frame (1) is provided with a height detection mechanism at the top. The height detection mechanism includes a first connecting rod (21) fixed to the top surface of the connecting frame (1). The bottom of the first connecting rod (21) is slidably connected to a limiting seat (22). The bottom surface of the limiting seat (22) is embedded with a second pressure sensor (23).

7. The automatic stacking device for the seedling raising tray according to claim 6, characterized in that: The top surface of the limiting seat (22) is provided with a third groove (24). The bottom of the first connecting rod (21) is slidably connected in the third groove (24). The bottom of the first connecting rod (21) is symmetrically fixed with a second connecting plate (25). The second connecting plate (25) is slidably connected in the third groove (24). A spring (26) is provided between the top of the second connecting plate (25) and the third groove (24). A gap (27) is provided between the second connecting plate (25) and the bottom surface of the third groove (24).

8. The automatic stacking device for the seedling raising tray according to claim 1, wherein: The lifting mechanism includes a second electric telescopic rod (28) fixedly connected to the conveying mechanism. A suction cup is fixedly connected to the top surface of the second electric telescopic rod (28), and the suction cup is connected to an air source (30) through a flexible hose (29).

9. The automatic stacking device for the seedling raising tray according to claim 2, characterized in that: The conveying mechanism includes a conveyor frame (31), a conveyor belt (32) is provided inside the conveyor frame (31), the first guide plate (3) is fixed to the top surface of the conveyor frame (31), and a second guide plate (33) is fixed to one end of the first guide plate (3) away from the limiting mechanism.

10. The automatic stacking device for the seedling raising tray according to claim 1, wherein: The seedling tray (2) has four corners on the top surface with limiting pins (34) and four corners on the bottom surface with limiting holes. The limiting pins (34) and limiting holes on two adjacent seedling trays (2) are compatible.

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