CN108184345B - A device for picking up and crushing farmland soil and gravel and returning them to the field - Google Patents

Abstract

The invention relates to the technical field of agricultural machinery, in particular to a farmland soil broken stone picking, crushing and returning device which comprises a soil entering part, a soil screening part and a crushing and returning part, wherein the soil entering part comprises a soil entering shovel, the soil screening part comprises a soil screening driving roller, a soil screening driven roller and a soil screening grid, and the crushing and returning part comprises a soil crushing roller, a soil crushing roller fixing plate and a primary/secondary soil crushing baffle. The depth of the front depth limiting wheel set is adjusted to adjust the depth of the soil entering the soil shovel; the soil inlet shovel and the soil screening grid are provided with intervals, so that fine soil particles can be conveniently screened out; the grating bars are used for conveying the stone blocks to a crushing and returning part; the gap between the first-stage/second-stage soil crushing baffle and the soil crushing roller is adjustable; the soil crushing roller and the soil crushing roller fixing plate are respectively and alternately provided with a soil crushing moving knife and a soil crushing fixing knife, the soil crushing moving knife and the soil crushing fixing knife are alternately distributed, the soil crushing roller fixing plate is provided with grid gaps, broken sand and stones leak to the ground through the grid gaps, and the leaked stones are continuously crushed in the inner cavity of the crushing returning part until the broken sand and stones leak to the ground completely.

Description

A device for picking up and crushing farmland soil and gravel and returning it to the field

Technical Field

The invention relates to the technical field of agricultural machinery, and in particular to a device for picking up, crushing and returning farmland soil and gravel to the field.

Background technique

In the process of farmland soil transformation, most of the soil is from the Gobi Desert or the front of the mountain or the hills, which contains a certain amount of gravel (stones) of varying sizes. These gravels seriously affect the operation of agricultural machinery (rotary tillers, deep tillers, fertilizer applicators, etc.), while sandy soil is conducive to soil loosening and ventilation. Therefore, it is necessary to pick up, crush and return the gravel in the crop tillage layer to the field.

In the existing agricultural machinery production practice, there is only a stone picking machine that picks up large stones on the soil surface and unloads the stones at the edge of the field. Since the stones are crushed and returned to the field, it is conducive to the loosening of the soil and the growth of crops (such as grapes, potatoes, peanuts, sweet potatoes, etc.). Therefore, the present invention designs a farmland soil gravel picking, crushing and returning device, which is used to pick up, crush and return the stones in the crop tillage layer (5-15cm) to the field, complete the operation at one time, and ensure the sandy soil quality of the soil.

Through searching domestic and foreign patent documents, journals and other publicly published documents (such as the Internet), it is found that the present invention has not been reported at home or abroad, and we have not published any articles related to the content of the present invention. The present invention is unknown to the public at home and abroad.

Summary of the invention

In view of the problems existing in the existing production practice, the purpose of the present invention is to provide a device for picking up, crushing and returning farmland soil and gravel to the field, which is used to solve the technical problems of digging the cultivated layer of soil, separating the soil from the stones, crushing the stones, adjusting the size of the crushed stones, and finally returning the crushed sand and gravel to the field.

In order to achieve the above purpose, the technical solution adopted by the present invention is:

A device for picking up and crushing farmland soil and gravel and returning it to the field, comprising: a frame part, a soil entering part, a soil screening part, a crushing and returning part to the field and four depth limiting wheel groups 23;

The frame part includes: a frame 1, a three-point suspension 2, a gearbox 3 and a reinforcement rod 4;

There are three three-point suspensions 2, two of which are fixed at the front of the frame 1, and the three-point suspension 2 at the upper end is fixedly connected to the upper ends of two reinforcing rods 4, and the lower ends of the two reinforcing rods 4 are fixedly connected to the rear of the frame 1 near the left and right ends; the gearbox 3 is fixed on the upper front of the frame 1;

The burying part includes: a burying shovel 5 and a burying shovel fixing plate 6; a plurality of spaces are provided in the middle of the burying shovel 5; the upper part of the burying shovel 5 is fixed to the bottom of the frame 1 through the burying shovel fixing plate 6;

The soil screening part comprises: a soil screening sprocket chain power group 7, a soil screening active roller 8, a soil screening driven roller 9, a soil screening bar grid 10, and a soil screening fixed plate 11;

There are two soil screening fixed plates 11 fixed at the lower middle part of the frame 1, and both ends of the soil screening active roller 8 and the soil screening driven roller 9 are fixed on the soil screening fixed plates 11 through bearings respectively; the left output shaft of the gearbox 3 transmits power to the soil screening active roller 8 through the soil screening sprocket chain power group 7, and the soil screening active roller 8 drives the soil screening driven roller 9 to rotate through the soil screening bar 10, and the soil screening bar 10 is provided with gaps;

The crushing and returning to the field part includes: a crushing belt group 12, a crushing roller 13, a crushing moving knife 14, a crushing fixed knife 15 and a crushing roller fixing plate 16;

The soil crushing roller fixing plate 16 is fixed to the rear part of the frame 1, and a plurality of rows of soil crushing fixed knives 15 are arranged in a staggered manner on the soil crushing roller fixing plate 16, and each row of soil crushing fixed knives 15 includes a plurality of soil crushing fixed knives 15, and each row of soil crushing fixed knives 15 is arranged in a lower semicircle; the right output shaft of the gearbox 3 is connected to the soil crushing roller 13 through the soil crushing belt group 12, and a plurality of rows of soil crushing movable knives 14 are arranged in a staggered manner around the soil crushing roller 13, and each row of soil crushing movable knives 14 includes a plurality of soil crushing movable knives 14, and the soil crushing movable knives 14 and the soil crushing fixed knives 15 are arranged in a staggered manner;

The four depth-limiting wheel groups 23 are respectively fixed under the four corners of the frame 1 to support the farmland soil and gravel picking, crushing and returning device. The burying depth of the shovel 5 is adjusted by adjusting the depth of the two depth-limiting wheel groups 23 at the front end of the frame 1.

On the basis of the above technical solution, a bar grid reinforcement plate 24 perpendicular to the earth-entering shovel 5 is fixedly provided near the bottom of the earth-entering shovel 5 to enhance the strength of the earth-entering shovel 5 .

On the basis of the above technical solution, the crushing and returning to the field part further includes: a crushing upper cover plate 17, a plurality of first-level crushing baffles 18, a plurality of first-level crushing baffle adjustment shafts 19, a plurality of second-level crushing baffles 20, and a plurality of second-level crushing baffle adjustment shafts 21;

The soil crushing upper cover plate 17 is fixed to the rear part of the frame 1, and forms a closed inner cavity with a front entrance with the soil crushing roller fixing plate 16; one end of a plurality of the first-level soil crushing baffles 18 are respectively fixed to a plurality of first-level soil crushing plate fixing points 28 on the soil crushing upper cover plate 17, and the middle parts of a plurality of the first-level soil crushing baffles 18 are respectively fixedly connected to one end of a plurality of first-level soil crushing baffle adjusting shafts 19, and the other end of the first-level soil crushing baffle adjusting shafts 19 passes through the soil crushing upper cover plate 17 and is fixed on the soil crushing upper cover plate 17, and the plurality of first-level soil crushing baffles 18 are respectively rotated around a plurality of first-level soil crushing plate fixing points 28 by adjusting the plurality of first-level soil crushing baffle adjusting shafts 19, so as to adjust the gap between the first-level soil crushing baffle 18 and the soil crushing movable knife 14 on the soil crushing roller 13;

The secondary soil crushing baffle 20 is located at the lower rear of the primary soil crushing baffle 18, one ends of a plurality of secondary soil crushing baffles 20 are respectively fixed to a plurality of secondary soil crushing plate fixing points 26 on the soil crushing upper cover plate 17, the middle parts of the plurality of secondary soil crushing baffles 20 are respectively fixedly connected to one ends of a plurality of secondary soil crushing baffle adjusting shafts 21, the other ends of the secondary soil crushing baffle adjusting shafts 21 pass through the soil crushing upper cover plate 17 and are fixed on the soil crushing upper cover plate 17, and the plurality of secondary soil crushing baffles 20 are respectively rotated around a plurality of secondary soil crushing plate fixing points 26 by adjusting the plurality of secondary soil crushing baffle adjusting shafts 21 to adjust the gap between the secondary soil crushing baffle 20 and the soil crushing movable knife 14 on the soil crushing roller 13.

On the basis of the above technical solution, a grid gap 27 is provided between each soil crushing fixed knife 15, so as to allow the stones crushed by the soil crushing movable knife 14 and the soil crushing fixed knife 15 to flow to the bottom surface.

On the basis of the above technical solution, the width of the grid gap 27 is determined according to the requirements of farmland soil.

Based on the above technical solution, the width of the grid gap 27 is 1-3 mm.

On the basis of the above technical solution, the inner sides of the primary soil crushing baffle 18 and the secondary soil crushing baffle 20 are both provided with trapezoidal distributed saw teeth 25 .

On the basis of the above technical solution, a soil retaining rubber plate 22 is arranged behind the inner cavity formed by the soil crushing upper cover plate 17 and the soil crushing roller fixing plate 16 to block the crushed small sand and soil to prevent dust from flying.

On the basis of the above technical solution, the farmland soil gravel picking, crushing and returning device is connected to the tractor via a three-point suspension 2.

On the basis of the above technical solution, the gearbox 3 is connected to the PTO power of the tractor through a coupling.

The present invention has the following advantages:

1. The soil screening part described in the present invention transmits power to the soil screening active roller 8 through the soil screening sprocket chain power group 7 through the left side output shaft of the gearbox 3. The soil screening active roller 8 drives the soil screening driven roller 9 to rotate through the soil screening bar grid 10. The two ends of the soil screening active roller 8 and the soil screening driven roller 9 are respectively fixed on the soil screening fixed plate 11 through bearings, and the soil screening fixed plate 11 is fixed on the frame 1 to realize the power transmission of soil screening.

2. The crushing and returning to the field part of the present invention is connected to the crushing roller 13 through the right side (based on the forward direction) output shaft of the gearbox 3 through the crushing belt group 12. Several rows of crushing knives 14 are arranged in a staggered manner around the crushing roller 13, and each row of crushing knives 14 includes a plurality of crushing knives 14. Several rows of crushing fixed knives 15 are arranged in a staggered manner on the crushing roller fixed plate 16, and each row of crushing fixed knives 15 includes a plurality of crushing fixed knives 15. Each row of crushing fixed knives 15 is arranged in a lower semicircular shape. The crushing knives 14 and the crushing fixed knives 15 are arranged in a staggered manner to crush stones. A grid gap 27 (usually the width of the grid gap 27 is 1-3mm) is set between the crushing fixed knives 15, and the crushed sand and stones can leak to the ground through the grid gap 27. The stones that cannot leak continue to be crushed and collided between the crushing knives 14 and the crushing fixed knives 15 until they leak to the ground, thereby achieving the crushing and returning of sand and stones to the field.

3. The two soil crushing roller fixing plates 16 described in the present invention are fixed to the rear part of the frame 1, and the soil crushing upper cover plate 17 is fixed to the upper rear part of the frame 1 to form a closed inner cavity with a small entrance with the soil crushing roller fixing plate 16. One ends of a plurality of primary soil crushing baffles 18 are respectively fixed to a plurality of primary soil crushing plate fixing points 28 on the soil crushing upper cover plate 17, and the middle parts of the plurality of primary soil crushing baffles 18 are respectively fixedly connected to one ends of a plurality of primary soil crushing baffle adjusting shafts 19, and the other ends of the primary soil crushing baffle adjusting shafts 19 pass through the soil crushing upper cover plate 17 and are fixed on the soil crushing upper cover plate 17. The plurality of primary soil crushing baffles 18 are respectively rotated around a plurality of primary soil crushing plate fixing points 28 by adjusting the plurality of primary soil crushing baffle adjusting shafts 19, so as to adjust the gap between the primary soil crushing baffle 18 and the soil crushing movable knife 14 on the soil crushing roller 13, thereby meeting the size requirements of soil and stone before and after crushing.

4. The secondary soil crushing baffle 20 and the secondary soil crushing baffle adjusting shaft 21 of the present invention are based on the same principle as the primary soil crushing baffle 18 and the primary soil crushing baffle adjusting shaft 19, and are also fixed on the soil crushing upper cover plate 17; the primary soil crushing baffle 18 and the secondary soil crushing baffle 20 are both provided with trapezoidal saw teeth 25 on the inner side, which can crush stones at multiple points.

5. A soil retaining rubber plate 22 is arranged behind the inner cavity formed by the soil crushing upper cover plate 17 and the soil crushing roller fixing plate 16 of the present invention, so as to facilitate the crushed small sand and soil to fall to the ground and avoid dust flying.

6. The four depth-limiting wheel groups 23 of the present invention are respectively fixed under the four corners of the frame 1, with two at the front end and two at the rear end, so as to balance the center of gravity of the machine. The two front depth-limiting wheel groups 23 can adjust the burying depth of the shovel 5.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention has the following accompanying drawings:

Figure 1 is a schematic diagram of the front view of the whole machine structure;

Figure 2 is a schematic top view of the entire structure;

Fig. 3 is a schematic diagram of the front view of the soil crushing roller part structure;

Fig. 4 is a schematic top view of a partial structure of a soil crushing roller;

FIG5 is a schematic cross-sectional view of the fixed position structure of the soil crushing movable knife and the soil crushing fixed knife.

Figure numerals: 1. Frame 2. Three-point suspension 3. Gearbox 4. Reinforced tie rod 5. Soil shovel 6. Soil shovel fixing plate 7. Soil screening sprocket chain power group 8. Soil screening active roller 9. Soil screening driven roller 10. Soil screening bar grid 11. Soil screening fixing plate 12. Soil crushing belt group 13. Soil crushing roller 14. Soil crushing moving knife 15. Soil crushing fixed knife 16. Soil crushing roller fixing plate 17. Soil crushing upper cover plate 18. First-level soil crushing baffle 19. First-level soil crushing baffle adjustment shaft 20. Second-level soil crushing baffle 21. Second-level soil crushing baffle adjustment shaft 22. Soil retaining rubber plate 23. Depth limiting wheel group 24. Bar grid reinforcement plate 25. Sawtooth 26. Second-level soil crushing plate fixing point 27. Grid gap 28. First-level soil crushing plate fixing point

Detailed ways

The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

The present invention is based on the following concept: (1) A device for picking up and crushing farmland soil and gravel and returning it to the field. According to the condition of soil and gravel, the height of the two depth-limiting wheel groups 23 in front of the device is adjusted, and then the soil entry depth of the soil shovel 5 is adjusted; according to the size of the soil stones before crushing and the requirements after crushing, the gaps between the first-level soil crushing baffle 18, the second-level soil crushing baffle 20 and the crushing moving knife (soil crushing moving knife) 14 are adjusted respectively; (2) The tractor is connected to the device of the present invention through a three-point suspension 2, and the tractor PTO power is connected to the gearbox 3 through a coupling, and then the soil screening part and the crushing and returning part are started respectively through the soil screening sprocket chain power group 7 and the soil crushing belt group 12; (3) The tractor is pulled As the machine moves, the soil-entering shovel 5 with a gap enters the soil and pushes the soil of the cultivated layer (the soil with a diameter larger than the gap of the soil-entering shovel 5) to the soil screening part. The soil screening part transports the soil with stones backward. The stones larger than the gap of the soil screening bar grid 10 continue to move backward under the push of the soil screening bar grid 10; the soil smaller than the gap of the soil screening bar grid 10 passes through the gap of the soil screening bar grid 10 and falls back to the ground; (4) The screened stones fall into the inner cavity of the crushing and returning part. Under the interactive action of the first-level crushing baffle 18, the second-level crushing baffle 20, the crushing movable knife 14, and the crushing fixed knife 15, the crushed small sand and gravel pass through the grid gap 27 between the crushing fixed knives 15 and fall to the ground; the stones that cannot fall out continue to stay in the crushing inner cavity and are hit by the crushing movable knife 14 and the crushing fixed knife 15 until they are crushed and leak out to the ground.

As shown in FIG. 1 and FIG. 2 , a farmland soil gravel picking, crushing and returning device mainly comprises: a frame part, a soil entering part, a soil screening part and a crushing and returning part;

The frame part includes: a frame 1, a three-point suspension 2, a gearbox 3 and a reinforcement rod 4;

The burying part includes: a burying shovel 5, a burying shovel fixing plate 6 and a bar grid reinforcement plate 24;

The soil screening part comprises: a soil screening sprocket chain power group 7, a soil screening active roller 8, a soil screening driven roller 9, a soil screening bar grid 10, and a soil screening fixed plate 11;

The crushing and returning to the field part includes: a soil crushing belt group 12, a soil crushing roller 13, a soil crushing moving knife 14, a soil crushing fixed knife 15, a soil crushing roller fixing plate 16, a soil crushing upper cover plate 17, a plurality of primary soil crushing baffles 18, a plurality of primary soil crushing baffle adjustment shafts 19, a plurality of secondary soil crushing baffles 20, and a plurality of secondary soil crushing baffle adjustment shafts 21;

The reinforcing rod 4 is connected to the three-point suspension 2 to fix the entire farmland soil and gravel picking, crushing and returning device to the field. The three-point suspension 2 and the gearbox 3 are both fixed on the frame 1;

There are multiple spaces in the middle of the soil shovel 5, which is convenient for soil entry and sifting out some fine soil (fine soil particles). A bar grid reinforcement plate 24 is fixed near the bottom to enhance the strength of the soil shovel 5. The soil shovel 5 is fixed to the frame 1 by a soil shovel fixing plate 6.

As shown in Figures 1 and 2, the output shaft on the left side (based on the forward direction) of the gearbox 3 transmits power to the soil screening active roller 8 through the soil screening sprocket chain power group 7. The soil screening active roller 8 drives the soil screening driven roller 9 to rotate through the soil screening bar grid 10. The two ends of the soil screening active roller 8 and the soil screening driven roller 9 are respectively fixed on the soil screening fixed plate 11 through bearings, and the soil screening fixed plate 11 is fixed on the frame 1.

As shown in Fig. 1-5, the right side (based on the forward direction) output shaft of the gearbox 3 is connected to the soil crushing roller 13 through the soil crushing belt group 12. A plurality of soil crushing movable knives 14 are arranged alternately around the soil crushing roller 13, and a plurality of soil crushing fixed knives 15 are arranged alternately on the soil crushing roller fixed plate 16. The soil crushing movable knives 14 and the soil crushing fixed knives 15 are arranged alternately to crush stones. Grid gaps 27 are provided between the soil crushing fixed knives 15 (depending on the requirements of farmland soil, the width of the grid gaps 27 is usually 1-3 mm). The crushed stones can leak to the ground through the grid gaps 27. The stones that cannot leak continue to be crushed and collided between the soil crushing movable knives 14 and the soil crushing fixed knives 15 until they leak to the ground.

The soil crushing roller fixing plate 16 is fixed to the rear part of the frame 1, and the soil crushing upper cover plate 17 is fixed to the rear part of the frame 1 to form a single-sided closed inner cavity with the soil crushing roller fixing plate 16. A plurality of soil crushing plate fixing points 28 on the soil crushing upper cover plate 17 are respectively fixed to one end of a plurality of primary soil crushing baffles 18, and the middle parts of the plurality of primary soil crushing baffles 18 are respectively connected to one end of a plurality of primary soil crushing baffle adjusting shafts 19, and the other end of the primary soil crushing baffle adjusting shaft 19 passes through the soil crushing upper cover plate 17 and is fixed on the soil crushing upper cover plate 17. By adjusting the plurality of primary soil crushing baffle adjusting shafts 19, the plurality of primary soil crushing baffles 18 are respectively rotated around the plurality of primary soil crushing plate fixing points 28, and then the gap between the primary soil crushing baffle 18 and the soil crushing movable knife 14 on the soil crushing roller 13 is adjusted;

The secondary soil crushing baffle 20 and the secondary soil crushing baffle adjusting shaft 21 are based on the same principle as the primary soil crushing baffle 18 and the primary soil crushing baffle adjusting shaft 19, and are also fixed on the soil crushing upper cover plate 17;

The first-stage soil crushing baffle 18 and the second-stage soil crushing baffle 20 have trapezoidal saw teeth 25 on their inner sides, which can crush rocks at multiple points.

A soil retaining rubber plate 22 is arranged behind the inner cavity formed by the soil crushing upper cover plate 17 and the soil crushing roller fixing plate 16 to facilitate the crushed small sand and soil to fall to the ground and avoid dust flying.

The four depth-limiting wheel groups 23 are respectively fixed under the four corners of the frame 1, distributed at two front ends and two rear ends, so as to support the farmland soil and gravel picking, crushing and returning device. The two front depth-limiting wheel groups 23 can adjust the soil entry depth of the soil shovel 5.

The general working process of the present invention is as follows: according to the condition of soil crushing, the two depth-limiting wheel groups 23 in front of the present invention are adjusted, and then the soil-entering depth of the soil-entering shovel 5 is adjusted; according to the size of the stones in the soil and the requirements after crushing, the gaps between the first-level soil-crushing baffle 18, the second-level soil-crushing baffle 20 and the crushing moving knife 14 are adjusted respectively by adjusting the first-level soil-crushing baffle adjustment shaft 19 and the second-level soil-crushing baffle adjustment shaft 21; the tractor is connected to the device of the invention through a three-point suspension 2, and the tractor PTO power is connected to the gearbox 3 through a coupling, and the soil screening part and the crushing and returning part are started respectively through the soil screening sprocket chain power group 7 and the soil crushing belt group 12; the tractor is running, the soil-entering shovel 5 enters the soil, and the soil-entering shovel 5 with a gap moves the soil of the cultivated layer The soil (soil with a diameter larger than the gap between the shovels 5) is pushed to the soil screening part, and the soil screening part transports the soil with stones backward. The stones larger than the soil screening bars 10 continue to move backward under the push of the soil screening bars 10; the soil smaller than the soil screening bars 10 falls back to the ground through the gaps between the soil screening bars 10; the screened stones fall into the inner cavity of the crushing and returning to the field part, and under the interactive action of the first-level soil crushing baffle 18, the second-level soil crushing baffle 20, the crushing movable knife 14, and the crushing fixed knife 15, the crushed small sand and gravel pass through the grid gap 27 between the crushing fixed knives 15 and fall to the ground; the stones that cannot leak out continue to stay in the crushing inner cavity, and are hit by the crushing movable knife 14 and the crushing fixed knife 15 until they are crushed and leak out to the ground.

The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the essence and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention is defined by the claims.

The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims (8)

1. A device for picking up and crushing farmland soil and gravel and returning it to the field, characterized in that it comprises a frame part, a soil entering part, a soil screening part, a crushing and returning part to the field and four depth limiting wheel groups (23); The frame part comprises: a frame (1), a three-point suspension (2), a gearbox (3) and a reinforcing tie rod (4); There are three three-point suspensions (2), the two three-point suspensions (2) at the lower end are respectively fixed to the front of the frame (1), the three-point suspension (2) at the upper end is fixedly connected to the upper ends of two reinforcing rods (4), and the lower ends of the two reinforcing rods (4) are respectively fixedly connected to the rear of the frame (1) near the left and right ends; the gearbox (3) is fixed to the upper front of the frame (1); The burying part comprises: a burying shovel (5) and a burying shovel fixing plate (6); a plurality of spaces are arranged in the middle of the burying shovel (5); the upper part of the burying shovel (5) is fixed to the bottom of the frame (1) through the burying shovel fixing plate (6); The soil screening part comprises: a soil screening sprocket chain power group (7), a soil screening active roller (8), a soil screening driven roller (9), a soil screening bar grid (10), and a soil screening fixed plate (11); There are two soil screening fixed plates (11) fixed at the lower middle part of the frame (1); the two ends of the soil screening active roller (8) and the soil screening driven roller (9) are respectively fixed on the soil screening fixed plates (11) through bearings; the left output shaft of the gearbox (3) transmits power to the soil screening active roller (8) through the soil screening sprocket chain power group (7); the soil screening active roller (8) drives the soil screening driven roller (9) to rotate through the soil screening bar grid (10); the soil screening bar grid (10) is provided with gaps; The crushing and returning to the field part comprises: a soil crushing belt group (12), a soil crushing roller (13), a soil crushing moving knife (14), a soil crushing fixed knife (15) and a soil crushing roller fixing plate (16); The soil crushing roller fixing plate (16) is fixed to the rear of the frame (1), and a plurality of rows of soil crushing fixed knives (15) are arranged in a staggered manner on the soil crushing roller fixing plate (16), each row of soil crushing fixed knives (15) includes a plurality of soil crushing fixed knives (15), and each row of soil crushing fixed knives (15) is arranged in a lower semicircular shape; the right output shaft of the gearbox (3) is connected to the soil crushing roller (13) through a soil crushing belt group (12), and a plurality of rows of soil crushing movable knives (14) are arranged in a staggered manner around the soil crushing roller (13), each row of soil crushing movable knives (14) includes a plurality of soil crushing movable knives (14), and the soil crushing movable knives (14) and the soil crushing fixed knives (15) are arranged in a staggered manner; The four depth-limiting wheel groups (23) are respectively fixed below the four corners of the frame (1) and are used to support the farmland soil and gravel picking, crushing and returning device. The depth of the soil-entering shovel (5) is adjusted by adjusting the depth of the two depth-limiting wheel groups (23) at the front end of the frame (1); A bar grid reinforcement plate (24) perpendicular to the earth-entering shovel (5) is fixedly provided near the bottom of the earth-entering shovel (5); The crushing and returning to the field part also includes: a crushing upper cover plate (17), a plurality of first-level crushing baffles (18), a plurality of first-level crushing baffle adjustment shafts (19), a plurality of second-level crushing baffles (20), and a plurality of second-level crushing baffle adjustment shafts (21); The soil crushing upper cover plate (17) is fixed to the rear of the frame (1) and forms a closed inner cavity with a front entrance with the soil crushing roller fixing plate (16); one end of a plurality of the first-level soil crushing baffles (18) are respectively fixed to a plurality of first-level soil crushing plate fixing points (28) on the soil crushing upper cover plate (17); the middle of a plurality of the first-level soil crushing baffles (18) are respectively fixedly connected to one end of a plurality of first-level soil crushing baffle adjustment shafts (19); the other end of the first-level soil crushing baffle adjustment shaft (19) passes through the soil crushing upper cover plate (17) and is fixed to the soil crushing upper cover plate (17); by adjusting the plurality of first-level soil crushing baffle adjustment shafts (19), the plurality of first-level soil crushing baffles (18) are respectively rotated around the plurality of first-level soil crushing plate fixing points (28) to adjust the gap between the first-level soil crushing baffles (18) and the soil crushing movable blade (14) on the soil crushing roller (13); The secondary soil crushing baffle (20) is located at the lower rear of the primary soil crushing baffle (18), one end of a plurality of secondary soil crushing baffles (20) is respectively fixed to a plurality of secondary soil crushing plate fixing points (26) on the soil crushing upper cover plate (17), the middle of the plurality of secondary soil crushing baffles (20) is respectively fixedly connected to one end of a plurality of secondary soil crushing baffle adjusting shafts (21), the other end of the secondary soil crushing baffle adjusting shaft (21) passes through the soil crushing upper cover plate (17) and is fixed on the soil crushing upper cover plate (17), and the plurality of secondary soil crushing baffles (20) are respectively rotated around the plurality of secondary soil crushing plate fixing points (26) by adjusting the plurality of secondary soil crushing baffle adjusting shafts (21) to adjust the gap between the secondary soil crushing baffle (20) and the soil crushing movable knife (14) on the soil crushing roller (13). 2. The farmland soil gravel picking, crushing and returning device as described in claim 1 is characterized in that a grid gap (27) is provided between each soil crushing fixed knife (15). 3. The farmland soil gravel picking, crushing and returning device as described in claim 2 is characterized in that the width of the grid gap (27) is determined according to the farmland soil requirements. 4. The farmland soil gravel picking, crushing and returning device as claimed in claim 3 is characterized in that the width of the grid gap (27) is 1-3 mm. 5. The farmland soil gravel picking, crushing and returning device as described in claim 1 is characterized in that the inner sides of the first-level soil crushing baffle (18) and the second-level soil crushing baffle (20) are both provided with trapezoidal distributed saw teeth (25). 6. The farmland soil gravel picking, crushing and returning device as described in claim 1 is characterized in that a soil retaining rubber plate (22) is arranged behind the inner cavity formed by the soil crushing upper cover plate (17) and the soil crushing roller fixing plate (16). 7. The device for picking up, crushing and returning farmland soil and gravel to the field as described in claim 1 is characterized in that the device for picking up, crushing and returning farmland soil and gravel to the field is connected to the tractor through a three-point suspension (2). 8. The farmland soil gravel picking, crushing and returning device as claimed in claim 1, characterized in that the gearbox (3) is connected to the PTO power of the tractor through a coupling.