A quickly replaceable forage seed combine harvester cleaning screen and replacement method

Abstract

The present invention discloses a quickly replaceable forage seed combine harvester cleaning screen and a replacement method. The cleaning screen includes a cleaning screen body and a cleaning screen pressing mechanism; the cleaning screen body includes an upper screen and a lower screen and a connecting rod mechanism for connecting the upper screen and the lower screen and enabling the upper screen and the lower screen to be opened and closed; the cleaning screen pressing mechanism is installed on a vibrating screen frame of the vibrating cleaning screen. The present invention is installed on a combine harvester. When replacing the cleaning screen, there is no need to disassemble the vibrating cleaning screen from the harvester as a whole. The screen piece to be replaced can be directly replaced, and the replaced cleaning screen is pressed by a unique pressing mechanism, thereby realizing the rapid replacement of the vibrating cleaning screen in the narrow space of the harvester, reducing labor intensity, improving work efficiency, reducing the damage to the machine caused by the overall disassembly of the vibrating screen, realizing the versatility of the forage seed vibrating cleaning screen, and providing equipment support for the harvesting of forage seeds.

Description

Technical Field

[0001] The invention relates to the technical field of forage seed combine harvester structures, and in particular to a quickly replaceable forage seed combine harvester cleaning screen and a replacement method. Background Art

[0002] my country has a wide variety of forage grasses and rich resources, but the seeds of various forage grasses have diverse shapes and large differences in physical properties. The planting area is not particularly large, which brings difficulties to mechanized harvesting. It is necessary to choose appropriate configuration parameters to obtain less loss and better harvesting effect.

[0003] At present, the harvesting of forage seeds in my country is generally carried out by seed combine harvesters. Due to the different physical properties of forage seeds, it is necessary to select the appropriate combine harvester configuration when harvesting different forage seeds. Among them, the vibrating cleaning screen device is a more important part of the combine harvester, which plays the function of sorting the forage seeds, broken segments and straw after harvesting and threshing.

[0004] At present, when a combine harvester harvests a large area of ​​rice and wheat seeds, it is not necessary to frequently replace the cleaning screen. However, when harvesting different types of forage seeds, due to the large variety of forage seeds, it is necessary to frequently replace the cleaning screen pieces of the vibrating cleaning screen. The forage seed combine harvester has a compact structure, and there is not enough space to remove the cleaning screen pieces on the combine harvester. Therefore, when replacing the cleaning screen pieces of the current forage seed combine harvester, the vibrating cleaning screen needs to be removed from the combine harvester as a whole for replacement. The frequent removal and replacement of the entire vibrating cleaning screen is time-consuming, troublesome, and the balance is destroyed, which causes great damage to the forage seed combine harvester. In view of the above, it is necessary to provide a quickly replaceable forage seed combine harvester cleaning screen and a replacement method. Summary of the invention

[0005] In view of the technical problems pointed out in the background technology, the object of the present invention is to provide a quickly replaceable forage seed combine harvester cleaning screen and a replacement method.

[0006] To achieve the above purpose, the technical solution provided by the present invention is as follows:

[0007] First aspect

[0008] The present invention provides a quickly replaceable cleaning screen for a forage seed combine harvester, wherein the cleaning screen can be detachably mounted on a vibrating cleaning screen, and comprises a cleaning screen body and a cleaning screen pressing mechanism for pressing the cleaning screen body;

[0009] The cleaning screen body comprises an upper screen and a lower screen arranged up and down, and a connecting rod mechanism for connecting the upper screen and the lower screen and enabling the upper screen and the lower screen to be opened and closed;

[0010] The upper screen comprises an upper screen frame, an upper screen compression spring, an upper screen piece, an upper screen pressure groove plate, an upper screen hexagonal bolt, and an upper screen locking butterfly nut. The front end of the upper screen piece is provided with a first long hole used in conjunction with the upper screen compression spring, and the rear end is provided with a first round hole used in conjunction with the upper screen hexagonal bolt; the upper screen frame is a square frame, the front end of which is provided with an upper screen compression spring, and both sides are provided with an inverted L-shaped upper screen pressure groove plate for guiding the installation of the upper screen piece. The upper screen piece is detachably mounted and hung on the upper screen frame through the upper screen compression spring, the upper screen hexagonal bolt, and the upper screen locking butterfly nut;

[0011] The lower screen comprises a lower screen frame, a lower screen compression spring, a lower screen piece, a lower screen pressure groove plate, a lower screen hexagonal bolt, and a lower screen locking butterfly nut. The front end of the lower screen piece is provided with a second long hole used in conjunction with the lower screen compression spring, and the rear end is provided with a second round hole used in conjunction with the lower screen hexagonal bolt; the lower screen frame is a square frame, the front end of which is provided with a lower screen compression spring, and both sides are provided with the lower screen pressure groove plate which is horizontal and used for guiding the installation of the lower screen piece. The lower screen piece is detachably mounted and hung on the lower screen frame through the lower screen compression spring, the lower screen hexagonal bolt, and the lower screen locking butterfly nut;

[0012] The cleaning screen pressing mechanism is installed on the vibrating screen frame of the vibrating cleaning screen, and the vibrating screen frame is provided with a fixing groove for installing the cleaning screen body. The inner sides of the fixing groove are symmetrically connected to the left and right pressing screen mechanisms. The left pressing screen mechanism includes a long connecting rod, a short connecting rod, a serrated connecting rod and a pull rod. The lower ends of the long connecting rod and the short connecting rod are respectively hingedly connected to the two ends of the serrated connecting rod, and the upper end of the short connecting rod is hingedly connected to the inner side of the vibrating screen frame near the front end of the vibrating cleaning screen. The middle part of the long connecting rod is hingedly connected to the vibrating The moving screen frame is hingedly connected to the inner side near the rear end of the vibrating cleaning screen, the upper end of the long connecting rod is detachably connected with a pull rod, a fixing plate is provided on the vibrating screen frame, one end of the pull rod passes through the fixing plate and is threadedly connected with the tightening nut, and the pull rod is tightened by using the tightening nut, wherein the long connecting rod and the short connecting rod are arranged in parallel and the distance between the hinge points of the two and the hinge point of the serrated connecting rod is equal, the long connecting rod, the short connecting rod and the serrated connecting rod form a parallelogram connecting rod mechanism with the vibrating screen frame, and the serrated connecting rod is pressed on the upper part of the upper screen.

[0013] A vibrating screen support plate is respectively arranged below the left pressing screen mechanism and the right pressing screen mechanism, a lower screen limiting plate is arranged at the lower part of the fixed groove close to the front end of the vibrating cleaning screen, an upper screen limiting plate is arranged above the lower screen limiting plate, the bottom of the lower screen is tightly attached to the vibrating screen support plate, the front end of the lower screen is tightly attached to the lower screen limiting plate, and the front end of the upper screen is tightly attached to the upper screen limiting plate.

[0014] Second aspect

[0015] The present invention also provides a method for replacing a quickly replaceable forage seed combine harvester cleaning screen, the method being used for replacing the above-mentioned quickly replaceable forage seed combine harvester cleaning screen, and is specifically as follows:

[0016] When installing the cleaning screen: rotate the left and right pressing screen mechanisms to raise the sawtooth connecting rod to the position of the rotating hinge point;

[0017] Put the upper screen frame and the lower screen frame together, with the lower screen at the front and the upper screen at the rear;

[0018] Put the closed cleaning screen between the concave plate of the threshing drum and the vibrating cleaning screen, press the bottom of the lower screen against the vibrating screen support plate, press the front end of the lower screen against the lower screen limit plate, then rotate the upper screen around the lower screen, press the front end of the upper screen against the upper screen limit plate, rotate the left pressing screen mechanism and the right pressing screen mechanism to press the serrated connecting rod against the upper screen, then use the tensioning nut to thread the tie rod, tighten the tie rod, and complete the installation of the cleaning screen;

[0019] When disassembling the cleaning screen: unscrew the tightening nut at one end of the pull rod from the pull rod, remove the pull rod from the connecting rod, rotate the left and right pressing screen mechanisms to raise the serrated connecting rod, and pull the cleaning screen body out from between the concave plate of the threshing drum and the vibrating cleaning screen to achieve rapid disassembly of the cleaning screen.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] The present invention is installed on a longitudinal axial flow forage seed combine harvester. When replacing the cleaning screen, there is no need to disassemble the vibrating cleaning screen from the harvester as a whole. The screen piece to be replaced can be directly replaced, and the replaced cleaning screen is compacted by a unique compacting mechanism, thereby realizing rapid replacement of the vibrating cleaning screen in a small space of the harvester, reducing labor intensity, improving work efficiency, reducing damage to the machine caused by overall disassembly of the vibrating screen, and realizing the versatility of the forage seed vibrating cleaning screen, so as to solve the difficult problem restricting the forage seed harvesting in my country and provide equipment support for the forage seed harvesting. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the structure of the cleaning screen body provided in the embodiment of the present application;

[0023] Figure 2 A schematic diagram of the structure of the upper screen provided in the embodiment of the present application;

[0024] Figure 3 A schematic diagram of the structure of the upper screen frame provided in an embodiment of the present application;

[0025] Figure 4 A schematic diagram of the structure of the upper screen provided in an embodiment of the present application;

[0026] Figure 5 A schematic diagram of the structure of the lower screen provided in the embodiment of the present application;

[0027] Figure 6 A schematic diagram of the structure of the lower screen frame provided in an embodiment of the present application;

[0028] Figure 7 A schematic diagram of the structure of the lower screen provided in an embodiment of the present application;

[0029] Figure 8 A schematic diagram of the structure of a vibrating cleaning screen provided in an embodiment of the present application;

[0030] Fig. 9 A schematic diagram of the installation structure of the left pressing screen mechanism provided in an embodiment of the present application;

[0031] Fig.10 A schematic diagram of the structure of the left pressing screen mechanism provided in an embodiment of the present application;

[0032] Fig.11 A schematic diagram of the structure of the cleaning screen installation process provided in the embodiment of the present application;

[0033] In the figure, lower screen 1; connecting rod mechanism 2; upper screen 3; upper screen compression spring 4; upper screen frame 5; upper screen piece 6; upper screen pressing slot plate 7; upper screen hexagonal bolt 8; upper screen locking butterfly nut 9; lower screen compression spring 10; lower screen frame 11; lower screen piece 12; lower screen pressing slot plate 13; left pressing screen mechanism 14; cleaning screen body 15; right pressing screen mechanism 16; vibrating screen frame 17; fixing plate 19; pulling rod 20; long connecting rod 21; vibrating screen support plate 22; serrated connecting rod 23; short connecting rod 24; lower screen limit plate 25; upper screen limit plate 26; threshing drum concave plate 27; vibrating cleaning screen 28; cleaning screen body 29; upper screen hexagonal bolt 30; upper screen locking butterfly nut 31. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0036] In the description of this patent, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, it can be fixedly connected or set, or it can be detachably connected or set, or connected or set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in this patent can be understood according to specific circumstances.

[0037] See also Figure 1-Figure 11 The structure of the embodiment provided by the present invention is shown in FIG.

[0038] This embodiment provides a quickly replaceable cleaning screen for a forage seed combine harvester, wherein the cleaning screen can be detachably mounted on a vibrating cleaning screen, and comprises a cleaning screen body 15 and a cleaning screen pressing mechanism for pressing the cleaning screen body;

[0039] The cleaning screen body comprises an upper screen 3 and a lower screen 1 arranged up and down, and a connecting rod mechanism for connecting the upper screen 3 and the lower screen 1 and enabling the upper screen 3 and the lower screen 1 to open and close;

[0040] The upper screen 3 includes an upper screen frame 5, an upper screen compression spring 4, an upper screen piece 6, an upper screen pressure groove plate 7, an upper screen hexagonal bolt 8, and an upper screen locking butterfly nut 9. The front end of the upper screen piece 6 is provided with a first long hole used in conjunction with the upper screen compression spring 4, and the rear end is provided with a first round hole used in conjunction with the upper screen hexagonal bolt 8; the upper screen frame 5 is a square frame, the front end of which is provided with an upper screen compression spring 4, and both sides are provided with an inverted L-shaped upper screen pressure groove plate 7 for guiding the installation of the upper screen piece 6. The upper screen piece 6 is detachably mounted and hung on the upper screen frame 5 through the upper screen compression spring 4, the upper screen hexagonal bolt 8, and the upper screen locking butterfly nut 9;

[0041] The lower screen 1 comprises a lower screen frame 11, a lower screen compression spring 10, a lower screen piece 12, a lower screen pressing groove plate 13, a lower screen hexagonal bolt 30, and a lower screen locking butterfly nut 31. The front end of the lower screen piece 12 is provided with a second long hole used in conjunction with the lower screen compression spring 10, and the rear end is provided with a second round hole used in conjunction with the lower screen hexagonal bolt 30; the lower screen frame 11 is a square frame, the front end of which is provided with a lower screen compression spring 10, and both sides are provided with the lower screen pressing groove plate 13 which is horizontal and used for guiding the installation of the lower screen piece 12. The lower screen piece 12 is detachably mounted and hung on the lower screen frame 11 through the lower screen compression spring 10, the lower screen hexagonal bolt 30, and the lower screen locking butterfly nut 31;

[0042] The cleaning screen pressing mechanism is installed on the vibrating screen frame 17 of the vibrating cleaning screen, and the vibrating screen frame 17 is provided with a fixing groove for installing the cleaning screen body, and the inner sides of the fixing groove are symmetrically arranged with a left pressing screen mechanism 14 and a right pressing screen mechanism 16, and the left pressing screen mechanism 14 includes a long connecting rod 21, a short connecting rod 24, a serrated connecting rod 23, and a pull rod 20. The lower ends of the long connecting rod 21 and the short connecting rod 24 are respectively hingedly connected to the two ends of the serrated connecting rod 23, and the upper end of the short connecting rod 24 is hingedly connected to the inner side of the vibrating screen frame 17 near the front end of the vibrating cleaning screen, and the middle part of the long connecting rod 21 is hingedly connected to the vibrating screen frame 1 7 is hingedly connected to the inner side near the rear end of the vibrating cleaning screen, the upper end of the long connecting rod 21 is detachably connected with the pull rod 20, and a fixing plate 19 is provided on the vibrating screen frame 17. One end of the pull rod 20 passes through the fixing plate 19 and is threadedly connected with the tightening nut 18, and the tightening nut 18 is used to tighten the pull rod 20, wherein the long connecting rod 21 and the short connecting rod 24 are arranged in parallel and the distance between the hinge points of the two and the hinge point of the serrated connecting rod 23 is equal, the long connecting rod 21, the short connecting rod 24 and the serrated connecting rod 23 and the vibrating screen frame 17 form a parallelogram connecting rod mechanism, and the serrated connecting rod 23 is pressed on the upper part of the upper screen 3.

[0043] A vibrating screen support plate 22 is respectively arranged below the left pressing screen mechanism 14 and the right pressing screen mechanism 16, a lower screen limiting plate 25 is arranged at the lower part of the fixed groove near the front end of the vibrating cleaning screen, an upper screen limiting plate 26 is arranged above the lower screen limiting plate 25, the bottom of the lower screen 1 is tightly attached to the vibrating screen support plate 22, the front end of the lower screen 1 is tightly attached to the lower screen limiting plate 25, and the front end of the upper screen 3 is tightly attached to the upper screen limiting plate 26.

[0044] Preferably, the connecting rod mechanism comprises two pairs of connecting rods 2 which are parallel and of equal length and located on both sides of the upper screen 3 and the lower screen 1, the upper and lower ends of the two pairs of connecting rods 2 are respectively hingedly connected to the upper screen 3 and the lower screen 1, and the two pairs of connecting rods 2 form a parallelogram structure with the upper screen 3 and the lower screen 1.

[0045] Preferably, the upper screen 6 comprises a flat woven screen, and the flat woven screen is wrapped with metal sheets to prevent curling and deformation.

[0046] Preferably, the lower screen plate 12 comprises a flat woven screen, and the flat woven screen is wrapped with metal sheets to prevent curling and deformation.

[0047] Preferably, one end of the pull rod (20) is hung in the upper end hole of the long connecting rod 21.

[0048] Preferably, the bottom of the sawtooth connecting rod 23 is sawtooth-shaped, which is conducive to compacting the vibrating screen.

[0049] This embodiment also provides a method for replacing a quickly replaceable forage seed combine harvester cleaning screen, which is used for replacing the above-mentioned quickly replaceable forage seed combine harvester cleaning screen, and is specifically as follows:

[0050] When installing the cleaning screen: rotate the left pressing screen mechanism 14 and the right pressing screen mechanism 16 to raise the sawtooth connecting rod 23 to the position of the rotating hinge point;

[0051] The upper screen frame 5 and the lower screen frame 11 are attached together, with the lower screen 1 at the front end and the upper screen 3 at the rear end;

[0052] Put the closed cleaning screen 29 between the concave plate 27 of the threshing drum and the vibrating cleaning screen 28, make the bottom of the lower screen 1 close to the vibrating screen support plate 22, and the front end of the lower screen 1 close to the lower screen limit plate 25, then rotate the upper screen 3 around the lower screen 1, and make the front end of the upper screen 3 close to the upper screen limit plate 26, and rotate the left pressing screen mechanism 14 and the right pressing screen mechanism 16 to make the serrated connecting rod 23 press on the upper screen 3, then use the tightening nut 18 to thread the pull rod 20, tighten the pull rod 20, and complete the installation of the cleaning screen;

[0053] When disassembling the cleaning screen: the process of disassembling the cleaning screen is the opposite of that of installing. Unscrew the tightening nut 18 at one end of the pull rod 20 from the pull rod 20, remove the pull rod 20 from the connecting rod, rotate the left clamping screen mechanism 14 and the right clamping screen mechanism 16 to raise the serrated connecting rod 23, and pull the cleaning screen body out from between the concave plate 27 of the threshing drum and the vibrating cleaning screen 28 to achieve rapid disassembly of the cleaning screen.

[0054] In addition, the disassembly and installation process of the cleaning screen body is as follows: after removing the upper screen hexagonal bolt 8, the upper screen locking butterfly nut 9 at the tail of the upper screen 3 and the lower screen hexagonal bolt 30 and the lower screen locking butterfly nut 31 at the tail of the lower screen 1 of the disassembled cleaning screen body, the upper screen plate 6 is pulled out along the middle of the track formed by the upper screen pressure slot plate 7 and the upper screen frame 5, and the lower screen plate 12 is pulled out along the track formed by the lower screen pressure slot plate 13 and the lower screen frame 11. Subsequently, the upper screen plate and the lower screen plate to be replaced are respectively installed on the upper screen frame 5 and the lower screen frame 11 through the corresponding tracks, and the front end is respectively compressed with the upper screen compression spring 4 and the lower screen compression spring 10, and the rear end is respectively locked with the upper screen hexagonal bolt 8, the upper screen locking butterfly nut 9 and the lower screen hexagonal bolt 30 and the lower screen locking butterfly nut 31 at the tail of the lower screen 1, so that the upper screen plate 6 and the lower screen plate 12 are respectively tightly fixed on the corresponding screen frames.

[0055] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A quickly replaceable forage seed combine harvester cleaning screen, characterized in that: The cleaning screen is detachably mounted on the vibrating cleaning screen, and comprises a cleaning screen body and a cleaning screen pressing mechanism for pressing the cleaning screen body; The cleaning screen body comprises an upper screen (3) and a lower screen (1) arranged one above the other, and a connecting rod mechanism for connecting the upper screen (3) and the lower screen (1) and enabling the upper screen (3) and the lower screen (1) to open and close; The upper screen (3) comprises an upper screen frame (5), an upper screen compression spring (4), an upper screen plate (6), an upper screen pressure groove plate (7), an upper screen hexagonal bolt (8), and an upper screen locking butterfly nut (9); the front end of the upper screen plate (6) is provided with a first long hole for use in conjunction with the upper screen compression spring (4), and the rear end is provided with a first round hole for use in conjunction with the upper screen hexagonal bolt (8); the upper screen frame (5) is a square frame, the front end of which is provided with an upper screen compression spring (4), and both sides are provided with an inverted L-shaped upper screen pressure groove plate (7) for guiding the installation of the upper screen plate (6); the upper screen plate (6) is detachably mounted and hung on the upper screen frame (5) through the upper screen compression spring (4), the upper screen hexagonal bolt (8), and the upper screen locking butterfly nut (9); The lower screen (1) comprises a lower screen frame (11), a lower screen compression spring (10), a lower screen plate (12), a lower screen pressure groove plate (13), a lower screen hexagonal bolt (30), and a lower screen locking butterfly nut (31); the front end of the lower screen plate (12) is provided with a second long hole used in conjunction with the lower screen compression spring (10), and the rear end is provided with a second round hole used in conjunction with the lower screen hexagonal bolt (30); the lower screen frame (11) is a square frame, the front end of which is provided with a lower screen compression spring (10), and both sides are provided with the lower screen pressure groove plate (13) which is transverse and used for guiding the installation of the lower screen plate (12); the lower screen plate (12) is detachably mounted and hung on the lower screen frame (11) through the lower screen compression spring (10), the lower screen hexagonal bolt (30), and the lower screen locking butterfly nut (31); The cleaning screen pressing mechanism is installed on a vibrating screen frame (17) of the vibrating cleaning screen. The vibrating screen frame (17) is provided with a fixing groove for installing the cleaning screen body. On both sides of the inner side of the fixing groove, there are a left pressing screen mechanism (14) and a right pressing screen mechanism (16) in a symmetrical structure. The left pressing screen mechanism (14) includes a long connecting rod (21), a short connecting rod (24), a sawtooth connecting rod (23), and a pull rod (20). The lower ends of the long connecting rod (21) and the short connecting rod (24) are respectively hingedly connected to the two ends of the sawtooth connecting rod (23). The upper end of the short connecting rod (24) is hingedly connected to the inner side of the vibrating screen frame (17) near the front end of the vibrating cleaning screen. The middle part of the long connecting rod (21) is hingedly connected to the vibrating screen frame (17). The inner side of the vibrating cleaning screen is hingedly connected near the rear end, the upper end of the long connecting rod (21) is detachably connected with a pull rod (20), and a fixing plate (19) is provided on the vibrating screen frame (17). One end of the pull rod (20) passes through the fixing plate (19) and is threadedly connected with a tightening nut (18), and the pull rod (20) is tightened by the tightening nut (18), wherein the long connecting rod (21) and the short connecting rod (24) are arranged in parallel and the distance between the hinge points of the two and the hinge point of the sawtooth connecting rod (23) is equal, and the long connecting rod (21), the short connecting rod (24) and the sawtooth connecting rod (23) and the vibrating screen frame (17) form a parallelogram connecting rod mechanism, and the sawtooth connecting rod (23) is pressed on the upper part of the upper screen (3); A vibrating screen support plate (22) is respectively arranged below the left pressing screen mechanism (14) and the right pressing screen mechanism (16); a lower screen limiting plate (25) is arranged at the lower part of the fixed groove near the front end of the vibrating screen; an upper screen limiting plate (26) is arranged above the lower screen limiting plate (25); the bottom of the lower screen (1) is tightly attached to the vibrating screen support plate (22); the front end of the lower screen (1) is tightly attached to the lower screen limiting plate (25); and the front end of the upper screen (3) is tightly attached to the upper screen limiting plate (26).

2. The quickly replaceable forage seed combine harvester cleaning screen according to claim 1, characterized in that: The connecting rod mechanism comprises two pairs of connecting rods (2) which are parallel and of equal length and are located on both sides of an upper screen (3) and a lower screen (1); the upper ends and lower ends of the two pairs of connecting rods (2) are respectively hingedly connected to the upper screen (3) and the lower screen (1); the two pairs of connecting rods (2) and the upper screen (3) and the lower screen (1) form a parallelogram structure.

3. The quickly replaceable forage seed combine harvester cleaning screen according to claim 1, characterized in that: The upper screen (6) comprises a flat woven screen, and the flat woven screen is wrapped by metal sheets to prevent curling and deformation.

4. The quickly replaceable forage seed combine harvester cleaning screen according to claim 1, characterized in that: The lower screen plate (12) comprises a flat woven screen, and the flat woven screen is wrapped around by metal sheets to prevent curling and deformation.

5. The quickly replaceable forage seed combine harvester cleaning screen according to claim 1, characterized in that: One end of the pull rod (20) is hung in the upper end hole of the long connecting rod (21).

6. The quickly replaceable forage seed combine harvester cleaning screen according to claim 1, characterized in that: The bottom of the sawtooth connecting rod (23) is sawtooth-shaped.

7. A method for replacing a quickly replaceable grass seed combine harvester cleaning screen, characterized in that: The method is used for replacing a quickly replaceable forage seed combine harvester cleaning screen as described in any one of claims 1 to 6, and is specifically as follows: When installing the cleaning screen: the left pressing screen mechanism (14) and the right pressing screen mechanism (16) are rotated to raise the sawtooth connecting rod (23) to the position of the rotating hinge point; The upper screen frame (5) and the lower screen frame (11) are fitted together, with the lower screen (1) at the front end and the upper screen (3) at the rear end; The closed cleaning screen (29) is fed between the concave plate (27) of the threshing drum and the vibrating cleaning screen (28), the bottom of the lower screen (1) is pressed against the vibrating screen support plate (22), the front end of the lower screen (1) is pressed against the lower screen limit plate (25), and then the upper screen (3) is rotated around the lower screen (1), and the front end of the upper screen (3) is pressed against the upper screen limit plate (26), and the left pressing screen mechanism (14) and the right pressing screen mechanism (16) are rotated to press the serrated connecting rod (23) against the upper screen (3), and then the tensioning nut (18) is threadedly connected to the pull rod (20), and the pull rod (20) is tightened to complete the installation of the cleaning screen; When disassembling the cleaning screen: unscrew the tension nut (18) at one end of the pull rod (20) from the pull rod (20), remove the pull rod (20) from the connecting rod, rotate the left pressing screen mechanism (14) and the right pressing screen mechanism (16) to raise the sawtooth connecting rod (23), and pull the cleaning screen body out from between the concave plate (27) of the threshing drum and the vibrating cleaning screen (28), so as to realize the rapid disassembly of the cleaning screen.

8. A method for replacing a quickly replaceable forage seed combine harvester cleaning screen according to claim 7, characterized in that: The disassembly and installation process of the cleaning screen body is as follows: after removing the upper screen hexagonal bolt (8) and the upper screen locking butterfly nut (9) at the tail of the upper screen (3) and the lower screen hexagonal bolt (30) and the lower screen locking butterfly nut (31) at the tail of the lower screen (1), the upper screen plate (6) is pulled out along the middle of the track formed by the upper screen pressure groove plate (7) and the upper screen frame (5), and the lower screen plate (12) is pulled out along the track formed by the lower screen pressure groove plate (13) and the lower screen frame (11). Subsequently, the upper screen plate and the lower screen plate to be replaced are respectively installed on the upper screen frame (5) and the lower screen frame (11) through corresponding rails, and the front ends are respectively compressed by the upper screen compression spring (4) and the lower screen compression spring (10), and the rear ends are respectively locked by the upper screen hexagonal head bolt (8), the upper screen locking butterfly nut (9) and the lower screen hexagonal head bolt (30) and the lower screen locking butterfly nut (31) at the tail of the lower screen (1), so that the upper screen plate (6) and the lower screen plate (12) are respectively tightly fixed on the corresponding screen frames.

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