A device for directional seeding of sand willow seedlings suitable for sandy environments

Abstract

This application relates to the field of forestry planting machinery and equipment technology, and discloses a directional sowing device for sandy willow seedlings suitable for sandy environments. The device includes a traveling vehicle with a lifting mechanism at its front end. A base is rotatably connected to the lifting end of the lifting mechanism. An outer shell is inserted through and fixedly connected to the center of the base. A high-frequency vibrator is installed on the outer wall of the base. An inner sleeve is embedded and slidably connected within the outer shell, and the two undergo axial relative displacement under the action of a cylinder. A conical valve assembly is installed at the bottom of the outer shell. Under gravity, the conical valve assembly remains perpendicular to the horizontal plane. The conical valve assembly is connected to the bottom of the inner sleeve via a linkage mechanism. The high-frequency vibrator, located on the outside of the base, induces a localized fluidization phase change in the surrounding sand during downward movement, maximizing the preservation of the fragile surface windbreak and sand-fixing crust, and fundamentally avoiding the planting risk of dry, shifting sand instantly flowing back and burying the planting holes.

Description

Technical Field

[0001] This invention relates to the field of forestry planting machinery and equipment technology, specifically to a directional sowing device for sandy willow seedlings suitable for sandy environments. Background Technology

[0002] As an extremely drought-resistant and wind-resistant shrub, *Salix psammophila* is widely used in desertification control and windbreak and sand-fixing projects. However, the mechanized large-scale sowing of *Salix psammophila* seedlings in arid sandy loam environments has always faced severe technical challenges due to the unique physical properties of the soil medium.

[0003] In conventional forestry or agricultural sowing operations, the topsoil is macroscopically cut and removed using machinery equipped with furrowing plows or augers. However, when these traditional agricultural machines are directly transplanted to desert environments, the dry sand particles lack cohesion and shear strength. When the machinery forcibly digs and breaks the soil, the dry, loose quicksand follows its unique angle of repose, instantly collapsing and flowing back towards the center of the newly dug trench. This not only makes it extremely difficult to create holes with machinery, but also causes sand willow seedlings to become severely tilted or even horizontally lodged when they fall into the trench due to the asymmetrical influx and compression of the surrounding sand. For plants like sand willow, which are often transplanted using semi-flexible cuttings or with roots, the inability to guarantee a directional planting posture with the buds facing upwards and vertical insertion will fatally reduce their photosynthetic efficiency and final survival rate.

[0004] Meanwhile, the terrain in desert areas is highly undulating, and vehicles inevitably pitch and roll when driving on sand dunes. Existing rigid pressing or plug-in seeding equipment often tilts in sync with the vehicle's posture, further amplifying the uncertainty of the seedling's entry angle into the soil. In addition, traditional mechanical cutting can disturb or even destroy the fragile windbreak and sand-fixing surface crust that has undergone a long period of natural evolution over a large area. This extensive operation method with large amounts of soil removal can easily lead to secondary desertification caused by intensified wind erosion in the work area.

[0005] To address these challenges, some studies have attempted to introduce multiple sets of electrically controlled actuators to separately control the opening, seedling placement, and soil covering actions. However, in field conditions with extreme winds and sandstorms and drastic temperature differences between day and night, the complex solenoid valves and sensing elements are prone to jamming and failure due to sand and dust intrusion; moreover, the vibrating environment often causes the clamping structure to become disconnected from the external opening action, resulting in engineering hazards such as seedlings slipping off prematurely or being crushed by the closing mechanism. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a directional sowing device for sandy willow seedlings suitable for sandy environments. It solves the problems of difficulty in hole formation and inaccurate vertical orientation of seedlings caused by the easy backflow and collapse of shifting sand when traditional forestry machinery is used in arid sandy soil, as well as the irreversible damage to the surface windbreak and sand-fixing crust caused by large-scale physical cutting and soil removal.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a directional sowing device for sandy willow seedlings suitable for sandy environments, comprising a traveling vehicle, a lifting mechanism at the front end of the traveling vehicle, a base rotatably connected to the lifting end of the lifting mechanism, an outer shell passing through and fixedly connected to the center of the base, a high-frequency vibrator on the outer wall of the base, an inner sleeve embedded and slidably connected within the outer shell, and the two undergo axial relative displacement under the action of a cylinder; a conical valve assembly is provided at the bottom end of the outer shell, and under the action of gravity, the conical valve assembly is horizontally... The surface remains vertical. The conical valve assembly is connected to the bottom end of the inner sleeve via a linkage mechanism. An auxiliary clamping assembly is provided inside the outer shell. When the inner sleeve is in a high position, the conical valve assembly is pulled by the linkage mechanism to maintain a closed state, and the auxiliary clamping assembly extends to flexibly clamp the sand willow seedling. When the inner sleeve is driven to move down by the cylinder and is in a low position, the inner sleeve pushes the conical valve assembly to unfold to a vertical state through the linkage mechanism, while simultaneously squeezing the auxiliary clamping assembly to retract, so that the sand willow seedling falls downward through the conical valve assembly under the action of gravity and vibration.

[0008] Preferably, the conical valve assembly includes four clips, which are arranged in a circular array around the axis of the outer shell. The top of each clip is rotatably connected to the bottom of the outer shell. When the four clips come together and abut, they form a cone for breaking sand.

[0009] Preferably, the linkage mechanism includes a push-pull rod, one end of which is rotatably connected to the bottom end of the inner sleeve, and the other end is rotatably connected to a rotating seat. The bottom wall of the rotating seat is fixedly connected to the side of the clamping petal facing the axis of the outer shell.

[0010] Preferably, the auxiliary clamping assembly includes four sliders, which are respectively embedded and slidably connected in the inner walls of the four corners of the outer casing. A return spring is also provided between the slider and the outer casing. The return spring is used to provide a horizontal preload force to the slider in the direction of the axis of the outer casing. The upper part of the slider is provided with an inclined surface that matches the slope of the bottom wall of the inner sleeve. When the inner sleeve moves down, the slider is driven to retract into the outer casing through the inclined surface.

[0011] Preferably, flexible bristles are fixedly connected to the side wall of the slider facing the axis of the outer shell. The flexible bristles are used to contact the sand willow seedlings and provide protective friction limit.

[0012] Preferably, a pressure ring is fitted and slidably connected to the lower outer wall of the outer casing. The pressure ring is connected to the top flange of the inner sleeve by a second return spring. When the inner sleeve moves down and is in a low position, the pressure ring is squeezed by the second return spring to move to the bottom of the outer casing. At this time, the lowest point of the cone valve assembly is higher than the bottom wall of the pressure ring. When the inner sleeve moves up and is in a high position, the pressure ring is pulled up by the second return spring.

[0013] Preferably, a spring return pin is also provided in the groove where the slider is embedded in the outer shell. One end of the outer cylinder wall of the spring return pin abuts against the first return spring, and the other end is fixedly connected to the side wall of the pressure ring. The telescopic end of the spring return pin passes through the first return spring. A groove matching the spring return pin is opened on the inner side of the pressure ring. When the inner sleeve moves down and drives the slider to retract into the outer shell, the slider pushes the spring return pin to move outward, so that the telescopic end of the spring return pin extends out of the outer shell. At this time, the telescopic end of the spring return pin is embedded in the groove, so that the pressure ring and the outer shell form a relatively fixed connection.

[0014] Preferably, the vibration frequency generated by the high-frequency exciter causes the sand in contact with the outer wall of the outer shell to produce a local fluidization effect. The lifting end of the lifting mechanism is fixedly connected to a vibration isolation support, and the top of the vibration isolation support is fixedly connected to a bearing seat. The rotating shafts at both ends of the base are inserted through and fixedly connected to the inner ring of the bearing in the bearing seat.

[0015] This invention provides a directional sowing device for willow seedlings suitable for sandy environments. It has the following beneficial effects: 1. This invention uses a high-frequency vibrator configured on the outside of the base to induce a local fluidization phase change in the surrounding sand during the downward movement, thereby sinking into the sand layer with extremely low physical resistance. After the seedlings are sown, during the process of the outer shell being pulled out, the fluidized sand gradually and automatically backfills due to the restriction of the outer shell. This in-situ piercing strategy completely abandons the powerful trenching and cutting mode of conventional agricultural machinery, preserves the integrity of the fragile surface windbreak and sand-fixing crust to the greatest extent, and fundamentally avoids the planting risk of dry quicksand instantly flowing back and burying the holes.

[0016] 2. This invention utilizes a purely mechanical rigid transmission—a push-pull rod forcibly opening the conical valve and the inclined surface of the inner sleeve squeezing the slider to retract—to convert the single axial downward displacement of the inner sleeve driven by the cylinder during seedling release into a synchronized action of opening the bottom valve and unlocking the internal mechanism. This achieves absolute synchronization between the lower sand-breaking channel's retraction and the loosening of the internal flexible clamping mechanism, eliminating the engineering risks of seedlings slipping prematurely or being jammed by structural components under strong vibration conditions. Simultaneously, the internal retraction and unlocking action is further endowed with the function of triggering external structural transformation. When the clamping slider retracts outward, it precisely pushes the spring reset pin into the groove on the inner side of the pressure ring, instantly completing the relative fixation between the pressure ring and the outer shell. At this moment, the bottom wall of the pressure ring is precisely at the lowest point of the entire component. This physical locking, directly induced by internal seedling release, smoothly transforms the outer components into a rigid, compacted ground surface without the need for additional electronically controlled valves or extra drives. With the pressure ring locked at the lowest point, the device can seamlessly engage in the subsequent root-fixing stage after the seedlings have fallen out. By controlling the lifting mechanism to drive the outer shell to move up and down, the rigid convex pressure ring can directly compact the sandy soil around the sowing position with high intensity. This in-situ compaction process greatly improves the density of the backfilled sand, which not only makes the seedling roots more firmly fixed, but also significantly enhances the ability of the newly planted area to resist natural wind erosion. Attached Figure Description

[0017] Figure 1 This is a three-dimensional schematic diagram of the present invention; Figure 2 This is a side view schematic diagram of the present invention; Figure 3 This is a schematic diagram of the linkage mechanism in this invention; Figure 4 for Figure 3 Enlarged view of point A in the middle; Figure 5 This is a schematic diagram of the auxiliary clamping component in the present invention; Figure 6 for Figure 5 Enlarged view at point B in the middle; Figure 7 for Figure 5 Enlarged view of point C in the middle.

[0018] The components include: 1. Walking vehicle; 2. Lifting mechanism; 3. Base; 4. Outer shell; 5. High-frequency vibrator; 6. Inner sleeve; 7. Cylinder; 8. Conical valve assembly; 801. Clamping disc; 9. Auxiliary clamping assembly; 901. Slider; 902. Return spring one; 903. Flexible bristles; 10. Push-pull rod; 11. Rotating seat; 12. Pressure ring; 1201. Groove; 13. Return spring two; 14. Spring return pin; 15. Vibration isolation support; 16. Bearing seat. Detailed Implementation

[0019] 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.

[0020] Please see the appendix Figure 1 - Appendix Figure 7 This invention provides a directional sowing device for sandy willow seedlings suitable for sandy environments, including a traveling vehicle 1. A lifting mechanism 2 is located at the front end of the traveling vehicle 1. A base 3 is rotatably connected to the lifting end of the lifting mechanism 2. An outer shell 4 is inserted through and fixedly connected to the center of the base 3. A high-frequency vibrator 5 is installed on the outer wall of the base 3. An inner sleeve 6 is embedded in and slidably connected to the outer shell 4, and the two undergo axial relative displacement under the action of a cylinder 7. A conical valve assembly 8 is located at the bottom of the outer shell 4. Under the action of gravity, the conical valve assembly 8 remains perpendicular to the horizontal plane. The component 8 is connected to the bottom end of the inner sleeve 6 by a linkage mechanism. An auxiliary clamping component 9 is provided inside the outer shell 4. When the inner sleeve 6 is in a high position, the linkage mechanism pulls the conical valve component 8 to keep it closed, and the auxiliary clamping component 9 extends to flexibly clamp the sand willow seedling. When the cylinder 7 drives the inner sleeve 6 to move down and is in a low position, the inner sleeve 6 pushes the conical valve component 8 to unfold to a vertical position through the linkage mechanism, while squeezing the auxiliary clamping component 9 to retract, so that the sand willow seedling falls downward through the conical valve component 8 under the action of gravity and vibration.

[0021] The vibration frequency generated by the high-frequency exciter 5 causes the sand around the outer wall of the outer shell 4 to produce a local fluidization effect. The lifting end of the lifting mechanism 2 is fixedly connected to the vibration isolation support 15. The top of the vibration isolation support 15 is fixedly connected to the bearing seat 16. The rotating shafts at both ends of the base 3 are inserted and fixedly connected to the bearing inner ring of the bearing seat 16.

[0022] First, the walking vehicle 1 is driven into the target sand dune area with undulating terrain, and the ground clearance of the seeding execution assembly is initially adjusted by the lifting mechanism 2 at the front end. Secondly, by utilizing the suspended rotating connection structure, the rotational degree of freedom of the seeding actuator is released, allowing it to hang freely under its own gravity and complete the attitude calibration perpendicular to the horizontal plane. Finally, the high-frequency vibrator 5, which is fixed to the outside of the seeding actuator assembly, is activated to transmit mechanical vibration to the actuator end, providing high-frequency excitation force for cutting into the dry sand layer.

[0023] In terms of specific mechanical structure assembly, the lifting end of the lifting mechanism 2 is rotatably connected to the base 3, and the outer shell 4 is vertically inserted and fixedly connected to the center of the base 3. The outer shell 4 is the basic reference component that subsequently supports all seedling release and compaction actions.

[0024] The aforementioned suspended articulated arrangement constructs a pendulum-like mechanical system unaffected by the chassis. Sand dune terrain often causes the vehicle 1 to be tilted uphill or downhill, but because the base 3 can rotate freely within the bearing seat 16, and the outer shell 4 and its internal core sleeve assembly possess considerable self-weight, the entire seeding assembly can continuously and stably maintain an absolutely vertical state under gravity. This physical characteristic ensures, from the outset, that the sand willow seedlings are aligned with the direction of gravity when planted.

[0025] Meanwhile, a high-frequency vibrator 5 is installed on the outer wall of the base 3. The mechanical oscillations output by the high-frequency vibrator 5 are transmitted downward along the rigid pipe wall of the outer shell 4 to change the physical phase state of the dry sand medium.

[0026] The lifting end of the lifting mechanism 2 is rigidly connected to a vibration isolation support 15, and the top of the vibration isolation support 15 is fixedly connected to a bearing seat 16. The two ends of the base 3 extend horizontally to form a rotating shaft, which passes through and is tightly fitted in the bearing inner ring of the bearing seat 16.

[0027] In this structural layout, the vibration isolation support 15 is connected in series on the force transmission path between the lifting mechanism 2 and the bearing seat 16, physically blocking the reverse transmission of the excitation force generated by the high-frequency vibrator 5 to the vehicle body 1. This structure effectively prevents high-frequency resonance from damaging the hydraulic system and electronic control components of the vehicle 1, and improves the mechanical fatigue life of the entire forestry machinery under harsh desert conditions.

[0028] The cone valve assembly 8 includes four clamping discs 801, which are arranged in a ring array with the outer housing 4 as the center. The top of the clamping discs 801 is rotatably connected to the bottom of the outer housing 4. When the four clamping discs 801 come together and abut, they form a cone for breaking sand.

[0029] In this embodiment, the structure and physical penetration mechanism of the outer shell 4 and its sand-breaking components are described in detail. To achieve low-disturbance puncture in dry sand, this invention utilizes the mechanical oscillation output by the high-frequency vibrator 5 to directly intervene in the physical characteristics of the interface between the actuator and the sand layer.

[0030] As the outer shell 4 gradually descends vertically under the drive of the lifting mechanism 2, the high-frequency vibrator 5 installed on the outer wall of the base 3 continues to work, transmitting the excitation force it generates along the pipe wall of the outer shell 4 to the ground surface. This high-frequency vibration input breaks the static friction and mechanical interlocking state between the stationary dry sand particles, forcing the sand particles around the outer wall of the outer shell 4 into a dynamic process of high-frequency free movement and rearrangement.

[0031] During this physical process, the local sand layer close to the outer wall of the outer shell 4 undergoes a fluidization phase change effect, exhibiting rheological properties similar to non-Newtonian fluids. Simultaneously, driven by the lifting mechanism 2, the outer shell 4 penetrates the surface windbreak and sand-fixing crust and the deep sand body, with its penetration resistance significantly reduced. This process primarily relies on the in-situ displacement and concession of sand particles, without macroscopic soil cutting and excavation, thus avoiding the irreversible damage to the desert surface ecological structure caused by traditional trenching operations.

[0032] To facilitate the fluidized bed puncture process and maintain a stable seedling space beneath the sand, this invention incorporates a dedicated conical valve assembly 8 at the bottom of the outer casing 4. This conical valve assembly 8 serves the dual mechanical functions of breaking up sand, guiding flow, and isolating the internal and external environments.

[0033] When the entire device sinks into the sand, the side edges of the four clamping petals 801 come together tightly and abut against each other due to the upward squeezing reaction force of the sand. In this posture, the four clamping petals 801 are geometrically assembled to form a streamlined solid cone, and the maximum outer diameter of the cone smoothly transitions with the outer wall of the outer shell 4.

[0034] As the fluidized sand grains slide upwards along the outer contour of the cone, the closed flaps 801 completely seal the opening at the bottom of the outer shell 4. This mechanical closure structure cuts off the path for the external high-pressure flowing sand to flow back into the equipment, thus ensuring that the interior of the outer shell 4 remains a hollow and clean tubular cavity deep within the dry sand, providing the foundation space for the subsequent vertical lowering of the sand willow seedlings.

[0035] The linkage mechanism includes a push-pull rod 10, one end of which is rotatably connected to the bottom end of the inner sleeve 6, and the other end is rotatably connected to a rotating seat 11. The bottom wall of the rotating seat 11 is fixedly connected to the side of the clamping petal 801 facing the axis of the outer shell 4.

[0036] The auxiliary clamping assembly 9 includes four sliders 901, which are respectively embedded and slidably connected in the inner walls of the four corners of the outer shell 4. A return spring 902 is also provided between the sliders 901 and the outer shell 4. The return spring 902 is used to provide a horizontal preload force to the sliders 901 in the direction of the axis of the outer shell 4. The upper part of the slider 901 is provided with an inclined surface that matches the slope of the bottom wall of the inner sleeve 6. When the inner sleeve 6 moves down, the slider 901 is driven to retract into the outer shell 4 through the inclined surface.

[0037] A flexible brush 903 is fixedly connected to the side wall of the slider 901 facing the axis of the outer shell 4. The flexible brush 903 is used to contact the sand willow seedling and provide protective friction limit.

[0038] In this embodiment, to achieve precise clamping and non-destructive synchronous release of the willow seedlings, the present invention constructs a purely mechanical linkage system based on axial relative sliding inside the outer shell 4. An inner sleeve 6 is embedded and slidably connected within the inner cavity of the outer shell 4, and the top end of the inner sleeve 6 is connected to the power output end of the cylinder 7. Driven by the cylinder 7, the inner sleeve 6 can generate controllable vertical relative displacement along the central axis inside the outer shell 4.

[0039] The outer casing 4 contains an auxiliary clamping assembly 9 for stabilizing the seedling's planting posture. In terms of spatial layout, this auxiliary clamping assembly 9 includes four sliders 901, which are respectively embedded in and horizontally slidably connected to the four corner inner wall grooves of the outer casing 4. Each slider 901 is fitted with a return spring 902 between itself and the inner substrate of the outer casing 4. The return spring 902 is in a compressed working state, continuously providing a horizontal radial preload force to the slider 901 in the direction of the outer casing 4's axis.

[0040] Furthermore, flexible bristles 903 are fixedly connected to the vertical sidewall of the slider 901 facing the center of the outer casing 4. When the cylinder 7 is in the extended state and the inner sleeve 6 is in the high position, the four sliders 901 extend towards the center of the cavity under the elastic thrust of the return spring 902. At this time, the sand willow seedling inserted from the top of the inner sleeve 6 is contacted and wrapped by the flexible bristles 903 around it. This structure provides protective physical friction limit for the seedling, firmly maintaining it in a vertical and neutral posture, avoiding damage to the bark of the branches caused by mechanical rigid compression. At the same time, the flexible bristles 903 also isolate high-frequency vibrations, preventing vibration from damaging the seedlings.

[0041] A linkage mechanism is provided between the cone valve assembly 8 and the bottom end of the inner sleeve 6. This linkage mechanism includes four push-pull rods 10. One end of each push-pull rod 10 is rotatably connected to the hinge point at the bottom end of the inner sleeve 6 via a pin, and the other end is rotatably connected to a rotating seat 11. The bottom wall of the rotating seat 11 is rigidly welded or bolted to the surface of the corresponding clamping petal 801 facing the inner side of the outer casing 4 axis.

[0042] During the seeding and release stage, cylinder 7 outputs a downward thrust to drive the inner sleeve 6 downward. A specific geometric slope is pre-formed on the upper part of slider 901, and this slope perfectly matches the slope of the end face of the bottom wall of the inner sleeve 6. As the inner sleeve 6 approaches and enters its lower position, its bottom wall directly abuts against the slope, generating relative sliding and converting the axial downward linear driving force into a radially outward lateral force. This lateral force overcomes the preload of the return spring 902, forcing the four sliders 901 to simultaneously retract into the inner wall of the outer shell 4, instantly releasing the flexible bristles 903 from clamping and binding the seedlings.

[0043] In perfect sync with the retraction action of the slider 901, the continuously descending inner sleeve 6 transmits rigid thrust to the conical valve assembly 8 at the bottom via four push-pull rods 10. Based on the rotational connection origin at the top of the clamping petals 801, the thrust applied to the rotating seat 11 by the push-pull rods 10 is converted into a flipping torque, pushing the four closed clamping petals 801 outward until each clamping petal 801 reaches a vertical state perpendicular to the horizontal plane. Under this condition, the lower anti-sand shield is completely opened, and the sand willow seedlings, no longer clamped, fall vertically along the through-hole under the combined action of their own gravity and the surrounding high-frequency vibrations, precisely positioning themselves at the bottom of the sand pit.

[0044] A pressure ring 12 is fitted and slidably connected to the lower outer wall of the outer casing 4. The pressure ring 12 is connected to the top flange of the inner sleeve 6 by a return spring 2 13. When the inner sleeve 6 moves down and is in a low position, the return spring 2 13 squeezes the pressure ring 12 to move to the bottom of the outer casing 4. At this time, the lowest point of the cone valve assembly 8 is higher than the bottom wall of the pressure ring 12. When the inner sleeve 6 moves up and is in a high position, the return spring 2 13 pulls the pressure ring 12 up.

[0045] A spring return pin 14 is also provided in the groove where the slider 901 is embedded in the outer shell 4. One end of the outer cylinder wall of the spring return pin 14 abuts against the return spring 902, and the other end is fixedly connected to the side wall of the pressure ring 12. The telescopic end of the spring return pin 14 passes through the return spring 902. The inner side of the pressure ring 12 is provided with a groove 1201 that matches the spring return pin 14. When the inner sleeve 6 moves down and drives the slider 901 to retract into the outer shell 4, the slider 901 pushes the spring return pin 14 to move outward, so that the telescopic end of the spring return pin 14 extends out of the outer shell 4. At this time, the telescopic end of the spring return pin 14 is embedded in the groove 1201, so that the pressure ring 12 and the outer shell 4 form a relatively fixed connection.

[0046] In this embodiment, the specific structure and action transmission mechanism of the mechanical interlocking triggered synchronously during the seedling release stage and the conversion to in-situ compaction mode are described in detail. In order to achieve tight compaction of the sandy soil around the sowing, the present invention assembles a pressure ring linkage system on the outside of the outer shell 4, which is directly triggered by the internal seedling release action.

[0047] An annular pressure ring 12 is fitted and slidably connected to the lower middle outer wall of the outer casing 4. This pressure ring 12 is configured to slide up and down within a defined range on the outer wall of the outer casing 4, primarily serving as the execution base for direct contact with the ground surface and vertical compaction. The upper edge of the pressure ring 12 is connected to the flange at the top of the inner sleeve 6 via a second return spring 13, which acts as the transmission medium for transmitting relative displacement and accumulating preload.

[0048] To construct a physical channel for transmitting internal actions to external components, spring return pins 14 are further horizontally slidably connected within four grooves where four sliders 901 are embedded in the outer casing 4. These spring return pins 14 are located in the rear space of the sliders 901, with one end of their outer cylindrical wall abutting and limiting the movement against the outer periphery of the aforementioned return spring 902. The telescopic probe end of the spring return pin 14 extends outward through the central axis of the return spring 902. Correspondingly, a locking groove 1201, whose position and diameter match the telescopic end of the spring return pin 14, is pre-formed on the inner cylindrical surface of the pressure ring 12. It should be noted that this locking groove 1201 consists of a transition groove axially penetrating the inner wall of the pressure ring 12 and a limiting hole. The limiting hole is located in the middle of the transition groove and has the greatest depth in terms of dimensions. The depth of the transition groove gradually increases from the limiting hole to the end face of the pressure ring 12, forming a symmetrical slope centered on the limiting hole.

[0049] When the device enters the seedling release mode, the inner sleeve 6 is driven downward by the cylinder 7 and is in a low position. The return spring 13 connected to the flange of the inner sleeve 6 is gradually compressed. This process converts the downward kinetic energy of the inner sleeve 6 into elastic potential energy, continuously applying a downward preload force to the pressure ring 12, forcing the pressure ring 12 to move downward along the outer wall of the outer shell 4 until it contacts the ground. After the seedlings are released, the lifting mechanism 2 drives the outer shell 4 upward until it is pulled out of the ground. At this time, the pressure ring 12, under its own weight and the downward preload force of the return spring 13, remains in contact with the ground. Simultaneously, the slider 901, squeezed by the inclined surface at the bottom of the inner sleeve 6, is rapidly retracting into the depth of the inner groove of the outer shell 4. At the end of the retraction displacement, the rigid rear wall of the slider 901 directly contacts and pushes the spring return pin 14 located in the same groove to move outward. The telescopic end of the spring return pin 14 then passes through the side wall hole of the outer casing 4. Simultaneously, during the relative displacement between the pressure ring 12 and the outer casing 4, the telescopic probe of the spring return pin 14 has an elastic telescopic function—that is, its telescopic probe can slide and extend along its outer cylinder. When it contacts the pressure ring 12, guided by the transition groove, the telescopic probe gradually retracts. When it passes the limiting hole, the compression disappears, and the telescopic probe instantly extends and inserts into the limiting hole, fixing the pressure ring 12 relative to the outer casing 4. At this time, the lowest point of the unfolded cone valve assembly 8 (i.e., the four clamping petals 801 in a vertical state) is higher than the bottom wall of the pressure ring 12, ensuring that the flat bottom surface of the pressure ring 12 becomes the final physical interface between the entire device and the external sand.

[0050] The above process instantly establishes a very firm relative connection between the originally sliding pressure ring 12 and the outer shell 4. This mechanical locking action requires no additional power source or solenoid valve control; its triggering sequence is rigidly nested within the same physical process of the slider 901 releasing the seedling. After the seedling successfully falls into the sandpit, the outer shell 4, which was originally responsible for the perforation shield, undergoes a fundamental transformation in its mechanical properties due to the bottom end being locked with the sturdy and flat pressure ring 12. It is ready to receive the macroscopic impact load transmitted from the upper lifting mechanism 2 at any time.

[0051] In this embodiment, a detailed analysis is provided of the dynamic operation process of the directional seeding device for sandy soil seedlings, suitable for sandy environments, throughout its entire life cycle within a single seeding cycle. This section uses time evolution as a guide to systematically demonstrate the physical linkage and operating condition switching mechanisms of the aforementioned sub-structural modules in a real sandy environment.

[0052] During the preparation phase, the mobile vehicle 1 drives into the target sand dune. Relying on the rotational hinge point constructed by the vibration isolation support 15 and the bearing seat 16, the outer shell 4 and the internal assembly naturally sag under gravity, automatically completing vertical centering. Subsequently, the cylinder 7 is in the extended state, the inner sleeve 6 is kept in the high position, and the bottom conical valve assembly 8 is pulled into a tightly closed state by the push-pull rod 10. At this time, the slider 901 of the auxiliary clamping assembly 9 extends under the push of the return spring 902, and the sand willow seedling is sent from the top of the device into the inner sleeve 6 by manual or robotic arm. The seedling falls down, and the roots are supported by the flexible bristles 903. The main stem of the seedling is located on the central axis of the inner sleeve 6.

[0053] Upon entering the drilling phase, the high-frequency vibrator 5 is activated, and simultaneously the lifting mechanism 2 is lowered to lower the actuator assembly. The four clamping petals 801 close to form a closed cone that cuts into the ground surface, and high-frequency oscillations are continuously transmitted outward through the outer shell 4. Under the excitation of high-frequency vibration, the dry sand particles at the contact interface lose their original static frictional engagement and undergo localized fluidization phase change. The outer shell 4 penetrates the windbreak and sand-fixing crust with minimal macroscopic penetration resistance and extends deep into the quicksand layer. Because the external sand is in a rheological state, it spontaneously yields to both sides, preventing excess sand from being turned over to the surface. The cone valve assembly 8 also prevents quicksand from entering the inner chamber.

[0054] After the device reaches the predetermined planting depth, it enters the seedling release and mechanical locking mode. Cylinder 7 retracts, driving the inner sleeve 6 to move downward relative to the inner cavity of the outer shell 4. The descending inner sleeve 6 forces the slider 901 to retract against the spring preload through the inclined end face, while the push-pull rod 10 at the bottom flips the clamping petals 801 downward to a vertically open state. The seedling, freed from lateral friction restraint, falls into the bottom sand pit without obstruction under the combined action of its own weight and high-frequency micro-vibration, achieving in-situ planting with zero drop. At the same frequency as the seedling falls, the retraction displacement of the slider 901 forcibly pushes the spring return pin 14 to move outward. At this time, the return spring 13, compressed by the downward pressure of the inner sleeve 6, has pushed the pressure ring 12 to contact the ground.

[0055] After in-situ planting, the lifting mechanism 2 drives the outer shell 4 to move upward. During this process, the pressure ring 12, under the combined action of its own weight and the downward preload of the return spring 13, remains in contact with the ground. At this time, the external appearance is that the pressure ring 12 is stationary while the outer shell 4 rises. During the rise of the outer shell 4, the surrounding sand in a fluidized state collapses and backfills towards the center under the action of gravity and vibration. When the outer shell 4 rises to a certain height, the spring return pin 14 contacts the groove 1201 of the pressure ring 12. Under the guidance of the transition groove, the telescopic probe gradually retracts. When it passes the limiting hole, the pressure disappears, and the telescopic probe instantly extends and inserts into the limiting hole, making the pressure ring 12 and the outer shell 4 relatively fixed. At this time, since the pressure ring 12 is at the lowest point and the bottom surface of the pressure ring 12 is flat, it completely protects the vertical clamping petals 801. The bottom of the outer shell 4 is physically transformed from a sand-breaking cone into a rigid, flat, and compacted working surface.

[0056] Finally, the in-situ compaction and repositioning process begins. The lifting mechanism 2 outputs alternating driving force, causing the outer shell 4 of the rigidly locked pressure ring 12 to move up and down in a limited stroke. The bottom wall of the pressure ring 12 directly compacts the loose sand layer around the seedling planting point. During this process, the fluidized surrounding sand is forcefully compressed and compacted by the pressure ring 12, firmly anchoring the willow seedling. After compaction, the lifting mechanism 2 lifts the outer shell 4 away from the sand surface, and the cylinder 7 immediately retracts and pulls up the inner sleeve 6. The spring reset pin 14, under the tension of its internal spring, disengages from the groove 1201, releasing the pressure ring 12 from locking. The push-pull rod 10 pulls the clamping petals 801 to close again, and the device returns to its initial position, ready for the next seedling planting cycle.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A directional sowing device for sandy willow seedlings suitable for sandy environments, comprising a traveling vehicle (1), characterized in that, The front end of the traveling vehicle (1) is provided with a lifting mechanism (2). The lifting end of the lifting mechanism (2) is rotatably connected to a base (3). A shell (4) is inserted through and fixedly connected to the center of the base (3). A high-frequency vibrator (5) is provided on the outer wall of the base (3). An inner sleeve (6) is embedded and slidably connected inside the shell (4). The two are axially relative to each other under the action of the cylinder (7). A conical valve assembly (8) is provided at the bottom of the shell (4). Under the action of gravity, the conical valve assembly (8) remains perpendicular to the horizontal plane. The conical valve assembly (8) and the bottom of the inner sleeve (6) are connected. The ends are connected by a linkage mechanism. An auxiliary clamping assembly (9) is provided inside the outer shell (4). When the inner sleeve (6) is in a high position, the linkage mechanism pulls the cone valve assembly (8) to keep it closed, and the auxiliary clamping assembly (9) extends to flexibly clamp the sand willow seedling. When the cylinder (7) drives the inner sleeve (6) to move down and is in a low position, the inner sleeve (6) pushes the cone valve assembly (8) to unfold to a vertical position through the linkage mechanism, and at the same time squeezes the auxiliary clamping assembly (9) to retract, so that the sand willow seedling falls down through the cone valve assembly (8) under the action of gravity and vibration. The auxiliary clamping assembly (9) includes four sliders (901). The four sliders (901) are respectively embedded and slidably connected in the inner walls of the four corners of the outer shell (4). A return spring (902) is also provided between the slider (901) and the outer shell (4). The return spring (902) is used to provide a horizontal preload force to the slider (901) in the direction of the axis of the outer shell (4). The upper part of the slider (901) is provided with an inclined surface that matches the slope of the bottom wall of the inner sleeve (6). When the inner sleeve (6) moves down, the slider (901) is driven to retract into the outer shell (4) through the inclined surface. A pressure ring (12) is fitted and slidably connected to the lower outer wall of the outer shell (4). The pressure ring (12) is connected to the top flange of the inner sleeve (6) by a second return spring (13). When the inner sleeve (6) moves down and is in a low position, the second return spring (13) provides a pre-tightening force to the pressure ring (12) to move down. At this time, the lowest point of the cone valve assembly (8) is higher than the bottom wall of the pressure ring (12). When the inner sleeve (6) moves up and is in a high position, the second return spring (13) pulls the pressure ring (12) up. A spring reset pin (14) is also provided in the groove where the slider (901) is embedded in the outer shell (4). One end of the outer cylinder wall of the spring reset pin (14) abuts against the first reset spring (902), and the other end is fixedly connected to the side wall of the pressure ring (12). The telescopic end of the spring reset pin (14) passes through the first reset spring (902). The inner side of the pressure ring (12) is provided with a groove (1201) that matches the spring reset pin (14). When the inner sleeve (6) moves down and drives the slider (901) to retract into the outer shell (4), the slider (901) pushes the spring reset pin (14) to move outward, so that the telescopic end of the spring reset pin (14) extends out of the outer shell (4). At this time, the telescopic end of the spring reset pin (14) is embedded in the groove (1201), so that the pressure ring (12) and the outer shell (4) form a relatively fixed connection.

2. The directional sowing device for *Salix psammophila* seedlings suitable for sandy environments according to claim 1, characterized in that, The conical valve assembly (8) includes four clamping petals (801). The four clamping petals (801) are arranged in a circular array with the axis of the outer shell (4) as the center. The top of the clamping petals (801) is rotatably connected to the bottom of the outer shell (4). When the four clamping petals (801) come together and abut, they form a cone for breaking sand.

3. The directional sowing device for *Salix psammophila* seedlings suitable for sandy environments according to claim 2, characterized in that, The linkage mechanism includes a push-pull rod (10), one end of which is rotatably connected to the bottom end of the inner sleeve (6), and the other end is rotatably connected to a rotating seat (11). The bottom wall of the rotating seat (11) is fixedly connected to the side of the clamping petal (801) facing the axis of the outer shell (4).

4. The directional sowing device for *Salix psammophila* seedlings suitable for sandy environments according to claim 1, characterized in that, The slider (901) has a flexible brush (903) fixedly connected to the side wall facing the axis of the outer shell (4). The flexible brush (903) is used to contact the sand willow seedling and provide protective friction limit.

5. A directional sowing device for sandy willow seedlings suitable for sandy environments according to claim 1, characterized in that, The vibration frequency generated by the high-frequency vibrator (5) causes the sand around the outer wall of the outer shell (4) to produce a local fluidization effect. The lifting end of the lifting mechanism (2) is fixedly connected to the vibration isolation support (15). The top of the vibration isolation support (15) is fixedly connected to the bearing seat (16). The rotating shafts at both ends of the base (3) are inserted and fixedly connected to the bearing inner ring of the bearing seat (16).

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