Small grain precision seeder

Abstract

The utility model relates to a small grain precision seeder which comprises a combined type rack, a power transmission assembly, a power harrow device, a press roller, a ditching, seeding and press unit, a soil covering device, a seed box assembly, a seed metering device seeding rate adjusting device and a seed adding pedal, the power transmission assembly is located on the front side of the combined type rack, and the power harrow device is arranged at the bottom of the front side of the combined type rack; a ditching, sowing and pressing unit is arranged at the bottom of the combined type rack, a soil covering device and a seed sowing device sowing amount adjusting device are arranged on the rear side of the bottom of the combined type rack, and a pressing roller driven by a power transmission assembly is further arranged on the power harrow device on the rear side of the harrow blade. According to the utility model, the whole structure is innovated, the working procedures of land ploughing, ditching, seeding, pressing and the like are integrated, high-standard and high-efficiency precision seeding can be achieved, the problem of single function of the existing seeding machine is solved, the conversion of large wheat and rape seeds can be quickly realized, and the problem of lack of general machines and tools for seeding small grains such as rape, wheat and the like is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of agricultural machinery, in particular to a precision seeder for small seeds. Background Art

[0002] At present, although there are many types of precision seeders for small seeds (such as barley, rapeseed, etc.) in China, the universality of the machines is poor, the overall working efficiency is low, the functions are single, and they cannot meet the requirements of modern large-field agricultural high-efficiency production. When the seeding unit sows seeds, it is unstable. The seeding rate adjustment mostly uses empirical data, which is prone to cause missed seeding and ridge breakage. The key components have no adjustment function, it is difficult to control the seeding depth of seeds during sowing, and the effect of covering the seeds is poor. Serious seed waste, low emergence rate, and uneven and weak seedlings. Content of the Utility Model

[0003] In order to solve the above problems, the purpose of the utility model is to provide a precision seeder for small seeds.

[0004] In order to achieve the above purpose, the technical solution of the utility model is: a precision seeder for small seeds, including a composite frame, a power transmission assembly, a power harrow device, a press roller, a ditching seeding and pressing unit, a soil covering device, a seed box assembly, a seeding rate adjustment device for the seed metering device, and a seed adding pedal. The power transmission assembly is located at the front side of the composite frame. A power harrow device is arranged at the bottom of the front side of the composite frame. A ditching seeding and pressing unit is arranged at the bottom of the composite frame. A soil covering device and a seeding rate adjustment device for the seed metering device are arranged at the rear side of the bottom of the composite frame. A seed box assembly is arranged inside the top of the front side of the composite frame. The seed box assembly is also provided with a seed adding pedal. The power transmission assembly drives the power harrow device to operate, and the power harrow device adopts a vertical rotary tillage structure. A double-layer steel plate structure is adopted at the bottom of the trough box of the power harrow device, and a harrow tooth fixing bracket is arranged. The harrow tooth fixing bracket fixes harrow discs through spring pins, and the harrow teeth are arranged in a staggered manner. A press roller driven by the power transmission assembly is also arranged at the rear side of the harrow discs of the power harrow device.

[0005] Further, the seeding rate adjustment device for the seed metering device includes a sprocket and chain drive and a ground wheel rotatably arranged at the outer end of the sprocket and chain drive. The ground wheel drives the transmission at one end of the multi-functional seed metering device to rotate through the sprocket and chain inside the sprocket and chain drive. The transmission is provided with a transmission adjustment rod for adjusting the transmission gear.

[0006] Furthermore, the ditching, seeding and rolling unit is arranged at the bottom of the rolling unit fixing frame of the composite frame. The rolling unit fixing frame includes a middle support square steel, a front square steel and a rear square steel which are fixedly connected before and after the middle support square steel. The front square steel, the rear square steel and the middle support square steel form a square steel frame. The upper end structures of the ditching, seeding and rolling unit are respectively fixedly connected to the front square steel and the rear square steel in a staggered manner. At both ends of the bottom of the driving harrow connecting frame, rolling unit connecting lugs III are respectively fixed. The rolling unit connecting lugs III are respectively rotatably connected to the middle support square steel through rolling unit connecting lugs I. Above the rolling unit connecting lugs III at each end, rolling unit connecting lugs IV are respectively fixed to the driving harrow connecting frame. Each rolling unit connecting lug IV is respectively rotatably connected to the middle support square steel through a rolling unit connecting lug II, so that the rolling unit connecting lug I, the rolling unit connecting lug II, the rolling unit connecting lug III and the rolling unit connecting lug IV form a quadrilateral link structure. A hydraulic telescopic oil cylinder is also arranged at the middle part of the middle support square steel.

[0007] Furthermore, the soil covering device includes a connecting telescopic square steel and spiral spring teeth. A plurality of spiral spring teeth are evenly and elastically fixed on the spiral spring tooth support square steel. Both ends of the spiral spring tooth support square steel are respectively fixedly connected to the connecting telescopic square steel on each side through soil covering connecting lugs I. At the other ends of the connecting telescopic square steel on each side, soil covering square pipes are respectively arranged. The soil covering square pipes are respectively fixedly connected to the soil covering connecting lugs II arranged on both sides of the seed adding pedal. The soil covering connecting lugs I on each side are fixedly connected to the soil covering angle adjusting plate of the connecting telescopic square steel.

[0008] Furthermore, each multi-functional seed metering device includes a seeding box and a grooved wheel group arranged at the inner bottom of the seeding box. A drawable seeding plug board is arranged above the grooved wheel group in the seeding box. A seed box cover is arranged at the upper opening of the seeding box in front of the grooved wheel group. A seeding tongue driven to open by the grooved wheel group is arranged at the bottom opening of the seeding box. A seeding tongue adjusting seat is arranged at the rotating part of the seeding tongue.

[0009] Furthermore, the ditching, seeding and rolling unit includes a rolling engagement and separation connecting arm and a rolling wheel soil cleaning plate arranged at the rear end of the rolling engagement and separation connecting arm. A fixed collar is arranged at the front end of the rolling engagement and separation connecting arm and is used for fixedly connecting with the corresponding part of the composite frame. A rolling buffer block is covered inside the fixed collar. A disc-shaped engagement and separation mud guard is fixed at the middle part of the rolling engagement and separation connecting arm. A freely rotatable engagement and separation disc is arranged on one side of the engagement and separation mud guard. An engagement and separation disc soil scraping plate is fixed at the top of the engagement and separation mud guard and is in contact with the periphery of the engagement and separation disc. A freely rotatable rolling wheel is arranged at the rear end of the rolling engagement and separation connecting arm. The outer end of the rolling wheel soil cleaning plate is in close contact with the periphery of the rolling wheel.

[0010] With the above settings, the utility model has the following characteristics:

[0011] The utility model is connected to a tractor. The composite frame adopts a three-point suspension method and is connected to the rear suspension of the tractor to drive the implement to operate.

[0012] That is, the combined machine mainly includes a front frame and a rear frame. The front frame is connected to the rear frame. The front frame mainly includes a power harrow device. The rear frame mainly includes a seed box assembly, a ditching, sowing and pressing unit, and a soil covering device. The rear frame is installed on the upper side steel of the pressing roller of the front frame, and the top is connected to the front frame by a high-strength adjustable connecting pin. From front to back, there are a power harrow device, a pressing roller, a ditching, sowing and pressing unit, and a soil covering device in sequence. The power harrow device mainly adopts a vertical rotary tillage method. The bottom of the trough box adopts a double-layer steel plate structure, and is equipped with a harrow tooth quick-change system. It adopts a spring pin design integrated in the harrow tooth fixing bracket. Only by rotating the spring pin can the harrow blades be replaced. All harrow teeth are arranged in a staggered manner at a certain angle and there is no interference between them during operation. A stone-proof deflector is set to protect the cutter shaft bearing mechanism. A pressing roller is arranged at the rear of the power harrow, which determines the working depth and the function of pressing the seedbed after harrowing. The seedbed pressing can ensure that the seeds sown subsequently are in close contact with the soil, achieving a good moisture-preserving effect and ensuring faster and neater emergence;

[0013] The seed box assembly adopts a partitioned box body, which is beneficial to maintaining the uniformity of the seeds in the box. The seed box assembly also includes a seed-adding pedal, which is convenient for manual seed addition and leveling; The ditching, sowing and pressing unit includes a multi-functional seed metering device, a seed metering device seeding rate adjustment device, an arch-shaped integrated double-disc ditching, sowing and pressing mechanism (i.e., the ditching, sowing and pressing unit), and multiple seed tubes and hoses;

[0014] The multi-functional seed metering devices are arranged and fixed at equal intervals at the bottom of the seed box. It is composed of a sowing box, a grooved wheel group, a sowing tongue, a sowing tongue adjustment seat, a seed box cover and an insertion plate. The seed metering device is convenient to replace; The seed metering device seeding rate adjustment device is composed of a ground wheel, a sprocket chain, a transmission and a transmission adjustment rod. The multi-functional seed metering device is driven by the ground wheel, and the seeding rate required for operation can be adjusted by the transmission adjustment rod before sowing;

[0015] The ditching, sowing and pressing unit is composed of a pressing buffer block, a pressing engagement and disengagement connecting arm, an engagement and disengagement mudguard, an engagement and disengagement disc, an engagement and disengagement disc soil scraping plate, a pressing wheel soil cleaning plate, a pressing wheel and bearings, and bearing seats, that is, an arch-shaped integrated double-disc ditching, sowing and pressing mechanism is formed. The pressing buffer block can effectively reduce the impact load caused by the unevenness of the field. The ditching, sowing and pressing units are installed in a staggered manner, increasing the gap between them, effectively solving the problem of the machine getting clogged with grass. The pressing engagement and disengagement connecting arm of the present utility model is made of aluminum alloy, with light weight, an arch shape, high yield strength and fatigue strength. The pressing wheel can be adjusted through a pressing adjustment device;

[0016] Multiple ditching, seeding and pressing units are fixed on two crossbeams, namely the front steel beam and the rear steel beam. The two crossbeams are fixed on the middle main crossbeam (i.e., the middle supporting square steel) one in front of the other. Connecting ears are provided on both sides of the middle supporting square steel for hinged fixation with the connecting ears on the crossbeam of the rear frame (i.e., the pressing unit fixing frame), enabling overall disassembly, facilitating the replacement of other monomers and subsequent maintenance. A hydraulic telescopic cylinder is welded at the middle part of the main crossbeam, and the hydraulic telescopic cylinder can adjust the height of the ditching, seeding and pressing unit;

[0017] The front and rear positions and angles of the soil covering device can be adjusted through the holes on the connecting ears to ensure the soil covering effect;

[0018] The power transmission assembly mainly includes a main transmission box. The main transmission box is connected to the PTO output device of the tractor through a universal joint, transmitting power to each power harrow tooth. The transmission gearbox adopts large-size bevel gears, and the meshing area between the teeth is larger, which can withstand ultra-high power loads.

[0019] In summary, the present utility model innovates the overall structure. The power harrow device forms a front-mounted vertical rotary harrowing structure, and a ditching, seeding and pressing unit is provided at the bottom of the composite frame. A soil covering device and a seeding rate adjusting device for the seed metering device are provided at the rear side of the bottom of the composite frame. A seed box assembly is provided inside the top of the front side of the composite frame, and a seed adding pedal is also provided on the seed box assembly, enabling the present utility model to integrate operations such as tilling the land, ditching, seeding, and pressing, achieving high-standard and high-efficiency precision seeding, solving the problem of the single function of existing seeders, and being able to quickly realize the conversion of barley, wheat and rapeseed seeds, solving the problem of the lack of general-purpose machines for sowing small seeds such as rapeseed and wheat. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a three-dimensional structure schematic diagram of the present utility model;

[0021] Figure 2 is a three-dimensional structure schematic diagram of the seeding rate adjusting device for the seed metering device of the present utility model;

[0022] Figure 3 is a three-dimensional structure schematic diagram of the pressing unit fixing frame of the present utility model;

[0023] Figure 4 is a three-dimensional structure schematic diagram of the soil covering device of the present utility model;

[0024] Figure 5 is a three-dimensional structure schematic diagram of the multi-functional seed metering device of the present utility model;

[0025] Figure 6 is a three-dimensional structure schematic diagram of the ditching, seeding and pressing unit of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The technical solution of the present utility model will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present utility model, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without making creative efforts belong to the scope of protection of the present utility model. In the description of the present utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0027] In the description of the present utility model, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0028] The following is a detailed description of this embodiment in conjunction with the accompanying drawings:

[0029] This embodiment provides a small-grain precision seeder. Please refer to the accompanying drawings in the specification together Figure 1-6 .

[0030] As Figure 1-6 shown, a small-grain precision seeder includes a composite frame 1, a power transmission assembly 2, a power harrow device 3, a press roller 31, a ditching, sowing and pressing unit 4, a soil covering device 5, a seed box assembly 6, a seed metering device 61 for adjusting the seeding rate, and a seed adding pedal 62. The power transmission assembly 2 is located at the front side of the composite frame 1. The power harrow device 3 is arranged at the bottom of the front side of the composite frame 1. The ditching, sowing and pressing unit 4 is arranged at the bottom of the composite frame 1. The soil covering device 5 and the seed metering device 61 for adjusting the seeding rate are arranged at the rear side of the bottom of the composite frame 1. The seed box assembly 6 is arranged inside the top of the front side of the composite frame 1. The seed box assembly 6 is also provided with a seed adding pedal 62. The power transmission assembly 2 drives the power harrow device 3 to operate, and the power harrow device 3 adopts a vertical rotary tillage structure. A double-layer steel plate structure is adopted at the bottom of the trough box of the power harrow device 3, and a harrow tooth fixing bracket is arranged. The harrow tooth fixing bracket fixes harrow discs through spring pins, and the harrow teeth are arranged in a staggered position. A press roller 31 driven by the power transmission assembly 2 is also arranged at the rear side of the harrow discs of the power harrow device 3.

[0031] The seeding rate adjusting device 61 of the seed metering device includes a sprocket and chain drive 612 and a ground wheel 611 rotatably arranged at the outer end of the sprocket and chain drive 612. The ground wheel 611 drives a transmission 614 at one end of the multi-functional seed metering device 41 to rotate through the sprockets and chains in the sprocket and chain drive 612. The transmission 614 is provided with a transmission adjusting rod 613 for adjusting the gear position of the transmission 614.

[0032] The ditching, sowing and pressing unit 4 is arranged at the bottom of the pressing unit fixing frame of the composite frame 1. The pressing unit fixing frame includes an intermediate support square steel 408 and a front square steel 409 and a rear square steel 407 fixedly connected before and after the intermediate support square steel 408. The front square steel 409, the rear square steel 407 and the intermediate support square steel 408 form a square steel frame. The upper end structures of the ditching, sowing and pressing unit 4 are respectively fixedly connected to the front square steel 409 and the rear square steel 407 in an alternating manner. At both ends of the bottom of the driving harrow connecting frame 406, there are respectively fixed pressing unit connecting ears three 403. The pressing unit connecting ears three 403 are respectively rotatably connected to the intermediate support square steel 408 through the pressing unit connecting ears one 401. Above the pressing unit connecting ears three 403 at each end, the driving harrow connecting frame 406 is respectively fixed with pressing unit connecting ears four 404. Each pressing unit connecting ear four 404 is respectively rotatably connected to the intermediate support square steel 408 through the pressing unit connecting ears two 402, so that the pressing unit connecting ears one 401, the pressing unit connecting ears two 402, the pressing unit connecting ears three 403 and the pressing unit connecting ears four 404 form a quadrilateral link structure. A hydraulic telescopic cylinder 405 is also arranged at the middle part of the intermediate support square steel 408.

[0033] The soil covering device 5 includes a connecting telescopic square steel 501 and spiral spring teeth 502. A plurality of spiral spring teeth 502 are elastically fixed on the spiral spring tooth support square steel 507 evenly. Both ends of the spiral spring tooth support square steel 507 are respectively fixedly connected to the connecting telescopic square steel 501 on each side through the soil covering connecting ears one 503. At the other ends of the connecting telescopic square steel 501 on each side, there are respectively arranged soil covering square pipes 504. The soil covering square pipes 504 are respectively fixedly connected to the soil covering connecting ears two 505 arranged on both sides of the seed adding pedal 62. The soil covering connecting ears one 503 on each side are fixedly connected to the soil covering angle adjusting plate 506 of the connecting telescopic square steel 501.

[0034] Each multi-functional seed metering device 41 includes a sowing box 411 and a grooved wheel group 412 arranged at the inner bottom of the sowing box 411. The sowing box 411 above the grooved wheel group 412 is provided with a drawable sowing plug board 413. Above the sowing box 411 in front of the grooved wheel group 412, there is an opening with a seed box cover 414. At the bottom opening of the sowing box 411, there is a sowing tongue 415 driven to open by the grooved wheel group 412. A sowing tongue adjusting seat 416 is arranged at the rotating part of the sowing tongue 415. The grooved wheel group 412 is in transmission connection with the power output shaft of the transmission 614, such as the grooved wheel group 412 and the transmission 614 structures commonly used in current seeders.

[0035] The ditching, seeding and pressing unit 4 includes a pressing engagement and disengagement connecting arm 432 and a soil cleaning plate 437 for the pressing wheel arranged at the rear end of the pressing engagement and disengagement connecting arm 432. A fixed collar is arranged at the front end of the pressing engagement and disengagement connecting arm 432 and is used for fixedly connecting with the corresponding part of the composite frame 1. A pressing buffer block 431 is covered inside the fixed collar. A disc-shaped engagement and disengagement mud guard 433 is fixed at the middle part of the pressing engagement and disengagement connecting arm 432. A rotatable engagement and disengagement disc 434 is arranged on one side of the engagement and disengagement mud guard 433. An engagement and disengagement disc soil scraping plate 435 is fixed at the top of the engagement and disengagement mud guard 433 and is in contact with the periphery of the engagement and disengagement disc 434. A rotatable pressing wheel 436 is arranged at the rear end of the pressing engagement and disengagement connecting arm 432. The outer end of the soil cleaning plate 437 for the pressing wheel is in close contact with the periphery of the pressing wheel 436.

[0036] Certainly, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A small-seed precise seeder, comprising a composite frame (1), a power transmission assembly (2), a power harrow device (3), a press roller (31), a ditching, sowing and pressing unit (4), a soil covering device (5), a seed box assembly (6), a seeding rate adjusting device (61) for the seed metering device, and a seed adding pedal (62), characterized in that: The power transmission assembly (2) is located on the front side of the compound frame (1). A power harrow device (3) is provided at the bottom of the front side of the compound frame (1). A ditching, seeding and pressing unit (4) is provided at the bottom of the compound frame (1). A soil covering device (5) and a seeder seeding rate adjusting device (61) are provided at the rear side of the bottom of the compound frame (1). A seed box assembly (6) is provided inside the top of the front side of the compound frame (1). The seed box assembly (6) is also provided with a seed adding pedal (62). The power transmission assembly (2) drives the power harrow device (3) to operate, and the power harrow device (3) adopts a vertical rotary tillage structure. A double-layer steel plate structure is adopted at the bottom of the trough box of the power harrow device (3), and a harrow tooth fixing bracket is provided. The harrow tooth fixing bracket fixes harrow discs through spring pins, and the harrow teeth are arranged in a staggered manner. A pressing roller (31) driven by the power transmission assembly (2) is also provided at the rear side of the harrow discs of the power harrow device (3).

2. The precision seeder for small seeds according to claim 1, characterized in that: The seeder seeding rate adjusting device (61) includes a sprocket and chain drive (612) and a ground wheel (611) rotatably provided at the outer end of the sprocket and chain drive (612). The ground wheel (611) drives a transmission (614) at one end of a multi-functional seeder (41) to rotate through the sprockets and chains inside the sprocket and chain drive (612). The transmission (614) is provided with a transmission adjusting rod (613) for adjusting the gear position of the transmission (614).

3. The precision seeder for small seeds according to claim 1, characterized in that: The ditching, seeding and pressing unit (4) is provided at the bottom of the pressing unit fixing frame of the compound frame (1). The pressing unit fixing frame includes an intermediate support square steel (408) and a front square steel (409) and a rear square steel (407) fixedly connected to the front and rear of the intermediate support square steel (408). The front square steel (409), the rear square steel (407) and the intermediate support square steel (408) form a square steel frame. The upper end structures of the ditching, seeding and pressing unit (4) are respectively fixedly connected to the front square steel (409) and the rear square steel (407) in a staggered manner. Two ends of the bottom of the driving harrow connecting frame (406) are respectively fixedly provided with pressing unit connecting lugs three (403). The pressing unit connecting lugs three (403) are respectively rotatably connected to the intermediate support square steel (408) through pressing unit connecting lugs one (401). Above each pressing unit connecting lug three (403) of the driving harrow connecting frame (406), pressing unit connecting lugs four (404) are respectively fixedly provided. Each pressing unit connecting lug four (404) is respectively rotatably connected to the intermediate support square steel (408) through pressing unit connecting lugs two (402), so that the pressing unit connecting lugs one (401), the pressing unit connecting lugs two (402), the pressing unit connecting lugs three (403) and the pressing unit connecting lugs four (404) form a quadrilateral link structure. A hydraulic telescopic cylinder (405) is also provided at the middle part of the intermediate support square steel (408).

4. A precise small-seed grain planter according to claim 1, characterized in that: The soil covering device (5) includes a connecting telescopic square steel (501) and spiral spring teeth (502). A plurality of spiral spring teeth (502) are evenly and elastically fixed on a spiral spring tooth support square steel (507). The two ends of the spiral spring tooth support square steel (507) are respectively fixedly connected to the connecting telescopic square steel (501) on each side through a soil covering connecting ear one (503). The other ends of the connecting telescopic square steels (501) on each side are respectively provided with soil covering square pipes (504), and the soil covering square pipes (504) are respectively fixedly connected to soil covering connecting ears two (505) arranged on both sides of the seeding pedal (62). The soil covering connecting ear one (503) on each side is fixedly connected to a soil covering angle adjusting plate (506) of the connecting telescopic square steel (501).

5. The precision seeder for small seeds according to claim 1, wherein: Each multifunctional seed metering device (41) includes a seeding box (411) and a grooved wheel group (412) arranged at the inner bottom of the seeding box (411). A drawable seeding plug board (413) is arranged in the seeding box (411) above the grooved wheel group (412). An opening is provided above the seeding box (411) in front of the grooved wheel group (412) with a seed box cover (414). An opening is provided at the bottom of the seeding box (411) with a seeding tongue (415) driven to open by the grooved wheel group (412). A seeding tongue adjusting seat (416) is arranged at the rotating part of the seeding tongue (415).

6. The precision seeder for small seeds according to claim 1, wherein: The furrowing, seeding and pressing unit (4) includes a pressing engagement and disengagement connecting arm (432) and a pressing wheel soil cleaning plate (437) arranged at the rear end of the pressing engagement and disengagement connecting arm (432). A fixed collar is arranged at the front end of the pressing engagement and disengagement connecting arm (432) for fixedly connecting to the corresponding part of the composite frame (1). A pressing buffer block (431) is covered inside the fixed collar. A disc-shaped engagement and disengagement mud guard (433) is fixed at the middle part of the pressing engagement and disengagement connecting arm (432). A rotatable engagement and disengagement disc (434) is arranged on one side of the engagement and disengagement mud guard (433). An engagement and disengagement disc soil scraping plate (435) is fixed at the top of the engagement and disengagement mud guard (433) and contacts the periphery of the engagement and disengagement disc (434). A rotatable pressing wheel (436) is arranged at the rear end of the pressing engagement and disengagement connecting arm (432). The outer end of the pressing wheel soil cleaning plate (437) is in close contact with the periphery of the pressing wheel (436).

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