Return sieve

Abstract

The utility model discloses a material returning screen which comprises a material returning screen box body, two vibration motors installed on the material returning screen box body, an upper screen mesh and a lower screen mesh, and the number of the vibration motors is two, and the vibration motors are installed on the outer side of the material returning screen box body through motor installation frames respectively. An output shaft of the vibration motor inwards extends into the inner side of the material returning screen box body and is positioned between the upper screen mesh and the lower screen mesh; an eccentric part is arranged on the output shaft of the vibration motor; a sleeve is arranged on the motor installation frame, the sleeve is located in the material returning screen box body and arranged on the outer sides of output shafts of the vibration motors on the two sides in a sleeving mode, and the two ends of the sleeve are connected with the motor installation frame on the two sides so that the sleeve can form a relatively-closed cavity. According to the material returning screen, the outer side of the output shaft of the vibration motor is sleeved with the material returning screen, the output shaft and eccentric parts on the output shaft can be effectively protected against interference of materials, generated dust and the like, smooth rotation is guaranteed, the service life of the vibration motor is prolonged, and normal use of the material returning screen is guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model relates to screening device technical field especially relates to a return material screen. BACKGROUND

[0002] The mobile screening station can be transported to the operation site to realize on-site screening, and has the advantages of convenient use and high production efficiency. The return material screen of the mobile screening station is provided with a vibrator to provide vibration power to realize vibration screening. The commonly used vibrator is a vibration motor, and an eccentric part is arranged on the output shaft of the vibration motor. The eccentric force generated by the high-speed rotation of the shaft and the eccentric block provides the exciting force. When the return material screen is assembled in the conventional way, the output shaft and the eccentric part thereon are located inside the return material screen. This arrangement can reduce the space occupation and facilitate the integration of the return material screen. However, the output shaft and the eccentric part thereon of the vibration motor are located inside the return material screen. The material to be screened and the dust generated act on the output shaft and the eccentric part thereon, which can easily affect the smooth rotation of the output shaft and even damage the output shaft and the eccentric part thereon, thereby affecting the normal use of the return material screen. SUMMARY

[0003] In view of the above problems, the utility model provides a return material screen which can solve the problem that the output shaft and the eccentric part thereon of the electric motor of the existing return material screen are easily disturbed by the material and dust and thus affect the normal operation.

[0004] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme:

[0005] A return material screen comprises a return material screen box, a vibration motor mounted on the return material screen box, an upper screen located at the top of the return material screen box, and a lower screen located below the upper screen. The upper screen and the lower screen are located inside the material screen box. The vibration motor is provided with an eccentric part on the output shaft. The output shaft of the vibration motor extends into the inside of the return material screen box and is located between the upper screen and the lower screen. The motor mounting bracket is provided with a sleeve. The sleeve is located inside the return material screen box and is sleeved on the outside of the output shaft of the vibration motor on both sides. The two ends of the sleeve are connected to the motor mounting brackets on both sides to form a relatively closed chamber.

[0006] Further, the motor mounting brackets on both sides are provided with extension plates. The extension plates of the two motor mounting brackets on both sides are oppositely arranged, and the extension plates on both sides are connected by connecting rods.

[0007] Further, the sleeve is provided with a maintenance window at the middle position, and a window baffle is detachably arranged at the position corresponding to the maintenance window.

[0008] Furthermore, circular rings coaxial with the sleeve are respectively provided at both ends of the sleeve, one side of the circular ring is in contact with and connected to the motor mounting frame, and a reinforcing rib is provided on the other side.

[0009] Furthermore, there are multiple upper screens, which are arranged in sequence longitudinally and cover the top opening of the return screen box;

[0010] Both sides of the upper screen are respectively provided with a first bending portion bent upward, and the first bending portion forms a first bayonet;

[0011] Tightening strips are provided on both sides of the return screen box at positions corresponding to the first bending portion. The cross section of the tightening strip is U-shaped, and one side of the tightening strip is hooked into the first bayonet. The tightening strip is detachably provided on the return screen box.

[0012] Furthermore, a supporting frame is fixedly provided at the top opening of the return screen box, and the upper screen is placed on the supporting frame.

[0013] Furthermore, both ends of the lower screen are respectively provided with a second bending portion bent downward, and the second bending portion forms a second bayonet;

[0014] A fixed positioning plate and a movable tensioning plate are fixedly provided in the return material screen box, and long holes are respectively opened on both sides of the middle of the return material screen box, and the two ends of the movable tensioning plate pass through the long holes to pass through the return material screen box and can move in the long holes along the length direction of the long holes; the second bent parts at both ends of the lower screen are hooked on the fixed positioning plate and the movable tensioning plate respectively through the second bayonet;

[0015] A fixed base plate and a movable base plate are fixedly provided on both sides of the return screen box, respectively. A first through hole is provided on the fixed base plate, and a first threaded hole is provided on the movable base plate at a position opposite to the first through hole. A screw passes through the first through hole and is screwed into the first threaded hole.

[0016] The movable base plate is attached to the side surface of the return material screen box body, and a through opening for passing the end portion of the movable tensioning plate is provided on the movable base plate.

[0017] Furthermore, a dustproof plate is fixedly provided on one side of the movable base plate attached to the return material screen box, and the dustproof plate is attached to the side surface of the return material screen box;

[0018] The dustproof plate is provided with a through hole of the same size as the end of the movable tensioning plate so that the end of the movable tensioning plate can pass through the dustproof plate, and the dustproof plate covers the long hole.

[0019] Furthermore, there are two lower screens, and the two lower screens are arranged side by side in front and back;

[0020] The corresponding two fixed positioning plates are respectively arranged in the middle of the return material screen box body, and the movable tensioning plates are respectively arranged at both ends of the return material screen box body. Maintenance windows are respectively provided at both ends of the return material screen box body, and maintenance window baffles are detachably provided at the positions corresponding to the maintenance windows.

[0021] Furthermore, dust baffles are respectively provided at the bottom edges of the return material screen box body, and the dust baffles are arranged to be inclined inwards and have a certain degree of flexibility.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: the return material screen of the present invention is arranged to be sleeved on the outside of the output shaft of the vibration motor and is connected to the motor mounting frames on both sides so that the sleeve forms a relatively closed chamber, effectively protecting the output shaft and the eccentric part thereon from interference from materials and generated dust, etc., ensuring smooth rotation, avoiding damage to the output shaft and the eccentric part thereon, extending the service life of the vibration motor, and ensuring the normal use of the return material screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the following briefly introduces the drawings required for describing the embodiments.

[0024] Figure 1 This is a schematic structural diagram of the return screen of the present utility model;

[0025] Figure 2 This is a schematic top view of the return screen of the present invention;

[0026] Figure 3 This is a schematic cross-sectional view of the return screen of the present utility model;

[0027] Figure 4 This is a structural diagram of the vibration motor, motor mounting bracket, etc. of the present utility model;

[0028] Figure 5 It is a cross-sectional schematic diagram of the utility model vibration motor, motor mounting frame, etc.;

[0029] Figure 6 It is a structural diagram of the load-bearing frame, upper screen, etc. of the utility model;

[0030] Figure 7 This is a schematic diagram of the assembly of the upper screen and the hooking strip of the utility model;

[0031] Figure 8 for Figure 1 A magnified schematic diagram of point A in the middle;

[0032] Figure 9 for Figure 3 Enlarged schematic diagram of point B in the middle.

[0033] Among them, the marks shown in the figure are: 10-return screen box; 11-hook and tightening strip; 12-carrying frame; 13-fixed positioning plate; 14-movable tensioning plate; 15-fixed base plate; 16-movable base plate; 17-screw; 18-through port; 19-dustproof plate; 110-maintenance window baffle; 111-dustproof baffle; 112-long hole; 20-vibration motor; 21-motor mounting bracket; 22-sleeve; 23-eccentric piece; 24-extension plate; 25-connecting rod; 26-window baffle; 27-ring; 28-reinforcement rib; 29-universal coupling; 30-upper screen; 31-first bending part; 32-first bayonet; 33-screw and nut assembly; 40-lower screen; 41-second bending part; 42-second bayonet; 50-spring assembly. DETAILED DESCRIPTION

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

[0035] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] Please refer to Figures 1 to 9 A preferred embodiment of the present invention provides a return screen, which mainly includes a return screen box 10, a vibration motor 20 installed on the return screen box 10, an upper screen 30 arranged on the top of the return screen box 10, and a lower screen 40 located below the upper screen 30.

[0038] The return screen box 10 is a chamber structure with open top and bottom. The upper screen 30 and the lower screen 40 are located inside the return screen box 10. The upper screen 30 is located at the open top of the return screen box 10, lower than the top of the return screen box 10 to form a groove structure with the top of the return screen box 10, so that the material can temporarily accumulate on the upper screen 30 after falling and will not fall out from the side of the return screen box 10. Of course, it is understandable that the return screen box 10 of the return screen is tilted as a whole, and the upper screen 30 is also tilted. For materials that cannot pass through the upper screen 30, they will be discharged from the lower end.

[0039] Spring assemblies 50 are respectively provided on both sides of the return screen box 10. There are multiple spring assemblies 50. The top of the spring assembly 50 is connected to the side of the return screen box 10 through a spring mounting seat, and a spring seat is provided at the bottom for connecting to an external support device, such as the main body of the screening station. At this time, the return screen box 10 is installed on the screening station through the spring assembly 50, and vibration screening is achieved through the deformation and reset function of the spring assembly 50.

[0040] Preferably, there are two vibration motors 20, each mounted on the outside of the return material screen housing 10 via a motor mounting bracket 21. The motor mounting bracket 21 is fixedly mounted on the side of the return material screen housing 10 and extends into the interior of the return material screen housing 10. The output shaft of the vibration motor 20 extends inwardly into the inside of the return material screen housing 10 and is located between the upper screen 30 and the lower screen 40. An eccentric member 23 is provided on the output shaft of the vibration motor 20. When the vibration motor 20 is running, it drives the output shaft and the eccentric member 23 thereon to rotate together. The centrifugal force generated by the high-speed rotation of the output shaft and the eccentric member 23 thereon obtains an exciting force, thereby achieving vibration. The two vibration motors 20 are arranged relative to each other and are located in the middle of the return material screen housing 10 to better drive the return material screen to vibrate. The output shafts of the two vibration motors 20 are connected to each other and are connected to each other at the connection point by a universal coupling 29. The movement of the eccentric members 23 on the output shafts of the two vibration motors 20 is consistent. The vibration motor 20 is a 64KN high-power vibration motor with a strong amplitude, which can screen larger and heavier materials.

[0041] The sleeve 22 is arranged on the motor mounting frame 21, is located in the return material screen box body 10, is sleeved outside the output shaft of the two side vibration motors 20, and is connected with the two side motor mounting frames 21 at both ends to form a relatively closed cavity. By forming the relatively closed cavity through the sleeve 22 and the two side motor mounting frames 21, the material and the generated dust can be effectively prevented from acting on the output shaft and the eccentric part thereon, the output shaft and the eccentric part thereon are effectively protected from the interference of the material and the generated dust, smooth rotation is ensured, the output shaft and the eccentric part thereon are prevented from being damaged, the service life of the vibration motor is prolonged, and normal use of the return material screen is ensured.

[0042] The extension plates 24 are arranged at the two sides of the motor mounting frame 21, the extension plates 24 of the two motor mounting frames 21 are oppositely arranged, and the extension plates 24 at the two sides are connected through the connecting rods 25. By arranging the connecting rods 25, the two motor mounting frames 21 are connected with each other, the stability between the motor mounting frames 21 is enhanced, loosening of the motor mounting frame 21 and the like during use is avoided, the stability of the sleeve 22 is ensured, and the output shafts of the two vibration motors 20 are centrally arranged. The sleeve 22 is provided with a maintenance window at the middle position, and the window baffle 26 is detachably arranged at the position corresponding to the maintenance window. The detachable connection is a screw connection. The maintenance window is aligned with the positions of the eccentric part 23, the universal joint 29 and the like, so that when maintenance is needed, the window baffle 26 can be temporarily removed for maintenance, and the entire sleeve 22 does not need to be removed, the maintenance efficiency is improved. The two ends of the sleeve 22 are respectively provided with the coaxial annular rings 27. One side of the annular ring 27 is in abutment and connected with the motor mounting frame 21, and the connection can be a screw connection. The other side is provided with the reinforcing ribs 28. The annular ring 27 can increase the contact area with the motor mounting frame 21 to facilitate installation. The reinforcing ribs 28 are axially arranged and fixedly connected with the annular ring 27 and the outer side of the sleeve 22, and can enhance the connection strength of the sleeve 22 and the annular ring 27.

[0043] In a preferred embodiment, there are three upper screens 30, and the upper screens 30 are manganese steel woven screens, which are resistant to smashing and have high wear resistance. The three upper screens 30 are arranged in sequence longitudinally and cover the top opening of the return screen box 10. At this time, the upper screen 30 adopts a segmented design and is divided into three identical sections. When necessary, the three sections can be replaced with each other, which has high interchangeability and is convenient for after-sales maintenance. When one upper screen 30 is damaged, the upper screen 30 can be replaced separately without replacing all the upper screens 30, thereby shortening the maintenance time and improving production efficiency. The upper screen 30 is provided with a first bending portion 31 that bends upward on both sides. The first bending portion 8131 bends upward and then continues to bend toward the inside of the return screen box 10. The bend forms an acute angle bend, and the first bending portion 31 forms a first bayonet 32. The two sides of the return screen box 10 are provided with hooking strips 11 at the positions corresponding to the first bending portion 31. The cross section of the hooking strips 11 is U-shaped as a whole. Figure 7 , one side of the hooking strip 11 is hooked into the first bayonet 32, and the U-shaped opening faces the outside of the return screen box 10. The hooking strip 11 is detachably arranged on the return screen box 10, and the detachable method is to connect the screw and nut assembly 33. By tightening the screw and nut assembly 33, the hooking strip 11 can be fixed to both sides of the return screen box 10, and when the screw and nut assembly 33 is tightened, the hooking strip 11 can be moved back and forth to the outside of the material screen box 10. At this time, the first bayonet 32 ​​formed by the first bent portion 31 is hooked by the hooking strip 11, which can realize the hooking and tightening of the upper screen 30 from both sides. The upper screen 30 is tightened by side tensioning, and the upper screen 30 is tightened by locking the hooking strip 11 with the screw and nut assembly 33. It is quick and convenient to install and easy to operate.

[0044] A load-bearing frame 12 is fixedly provided at the top opening of the return screen box 10. The load-bearing frame 12 is a frame structure, and the upper screen 30 is placed on the load-bearing frame 12. The load-bearing frame 12 can support the upper screen 30 to a certain extent, and when the upper screen 30 has a certain slack after long-term use, it can be taken up by the load-bearing frame 12, thereby slowing down the scrapping speed and extending the operation time.

[0045] In a preferred embodiment, the lower screen 40 is provided with downwardly curved second bends 41 at each end, forming second openings 42. After bending downward, the second bends 41 further bend toward the inside of the return screen housing 10, forming an acute angle. The lower screen 40 adopts a banana screen structure, with a curved screen that allows for more thorough and clean screening of materials.

[0046] A fixed positioning plate 13 and a movable tensioning plate 14 are fixedly installed in the return material screen box 10. An elongated hole 112 is respectively opened on both sides of the middle portion of the return material screen box 10. The length direction of the elongated hole 112 is the front and rear end direction of the return material screen box 10. The two ends of the movable tensioning plate 14 pass through the elongated hole 112 to pass through the return material screen box 10 and can move in the elongated hole 112 along the length direction of the elongated hole 112. The second bent portions 41 at both ends of the lower screen 40 are hooked on the fixed positioning plate 13 and the movable tensioning plate 14 respectively through the second bayonet 42. It can be understood that when the movable tensioning plate 14 moves away from the fixed positioning plate 13, it can drive the end of the lower screen 40 hooked on the movable tensioning plate 14 to move away from the fixed positioning plate 13. At this time, the end hooked on the fixed positioning plate 13 does not move, and the lower screen 40 is tightened.

[0047] A fixed base plate 15 and a movable base plate 16 are fixedly provided on both sides of the return screen box 10. The fixed base plate 15 is provided with a first through hole, and a first threaded hole is provided on the movable base plate 16 at a position opposite the first through hole. A screw 17 passes through the first through hole and is screwed into the first threaded hole. The movable base plate 16 is attached to the side of the return screen box 10. At this time, the fixed base plate 15, the movable base plate 16 and the screw 17 form a screw substructure. By turning the screw 17, the movable base plate 16 can be driven to move. The direction of movement of the movable base plate 16 is the front and rear end direction of the return screen box 10. The movable base plate 16 is provided with a through hole 18 for passing the end of the movable tensioning plate 14. When the end of the movable tensioning plate 14 enters the through hole 18 of the movable base plate 16, it is limited by the through hole 18 so that when the movable base plate 16 moves back and forth in the front and rear end direction of the material screen box 10, it can move back and forth in the front and rear end direction of the material screen box 10 together with it.

[0048] There are two lower screens 40, which are arranged side by side in front and back. The corresponding two fixed positioning plates 13 are respectively set in the middle of the return material screen box 10, and the movable tensioning plates 14 are respectively set at both ends of the return material screen box 10. Two sets of fixed base plates 15, movable base plates 16, and screws 17 are respectively provided, located at the front and rear ends of the return material screen box 10. One set of fixed base plates 15, movable base plates 16, and screws 17 corresponds to one lower screen 40. During operation, by turning the screw 17, the movable base plates 16 are driven to move back and forth toward the end of the material screen box 10, thereby driving the movable tensioning plates 14 to move back and forth toward the end of the material screen box 10 to achieve the tensioning of the lower screen 40. The tightening method of the lower screen 40 is to tighten at both ends. The purpose of adjusting the tightening of the lower screen 40 is achieved by adjusting the tightness of the screw 17 at the end of the return screen box 10. The tightening form at both ends can eliminate the need for maintenance personnel to climb into the screen body to replace the screen, further improving the safety performance of maintenance personnel and avoiding unnecessary accidents.

[0049] The two ends of the return screen box body 10 are respectively provided with maintenance windows, and maintenance window baffles 110 are detachably arranged at positions corresponding to the maintenance windows. When maintenance of the lower screen 40 is required, the maintenance window baffles 110 are removed to realize the maintenance.

[0050] The dustproof plate 19 is fixedly arranged on one side of the return screen box body 10 and is attached to the side of the return screen box body 10. The dustproof plate 19 is provided with a through hole with the same size as the end of the movable tension plate 14, so that the end of the movable tension plate 14 can pass through the dustproof plate 19. The dustproof plate 19 covers the long hole 112. The dustproof plate 19 is made of a rubber plate with a certain flexibility. The long hole 112 has a certain length, and the movable tension plate 14 needs to move in it and cannot be completely covered. At this time, the dust generated by the screening will come out of the long hole 112 and fall into the screw hole of the screw rod 17 and the movable base plate 16, thereby being not conducive to the screwing of the screw rod 17. By arranging the dustproof plate 19, even if the movable base plate 16 moves, the dustproof plate 19 will cover the entire long hole 112, so that dust will not float out, effectively avoiding the interference of dust on the screw rod 17 and the screw hole of the movable base plate 16.

[0051] In the preferred embodiment, dustproof baffles 111 are arranged at the bottom edges of the return screen box body 10. The dustproof baffles 111 are inwardly inclined and have a certain flexibility. The flexible dustproof baffles 111 can be made of a rubber plate or the like. Because they have a certain flexibility, they can be inclined and deformed upward when the return screen box body 10 moves downward, and can be unfolded when the return screen box body 10 moves upward, thereby being attached to the device (such as a conveyor belt) below the return screen box body 10. On the one hand, it can effectively prevent the material coming out of the bottom of the return screen box body 10 after screening from going out from both sides to prevent material leakage, and on the other hand, it can effectively prevent dust from spreading out from the bottom to pollute the surrounding links.

[0052] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto. Any changes or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A return screen, comprising a return screen box (10), a vibration motor (20) mounted on the return screen box (10), an upper screen (30) arranged on the top of the return screen box (10), and a lower screen (40) located below the upper screen (30), wherein the upper screen (30) and the lower screen (40) are located inside the return screen box (10), characterized in that: There are two vibration motors (20), which are respectively mounted on the outside of the return screen box (10) through motor mounting frames (21). The output shaft of the vibration motor (20) extends inwardly into the inside of the return screen box (10) and is located between the upper screen (30) and the lower screen (40). An eccentric piece (23) is provided on the output shaft of the vibration motor (20); a sleeve (22) is provided on the motor mounting frame (21), and the sleeve (22) is located in the return screen box (10) and is sleeved on the outside of the output shafts of the vibration motors (20) on both sides. The two ends of the sleeve (22) are respectively connected to the motor mounting frames (21) on both sides so that the sleeve (22) forms a relatively closed chamber. The two ends of the lower screen (40) are respectively provided with second bent portions (41) bent downwards, and the second bent portions (41) form second bayonet openings (42); A fixed positioning plate (13) and a movable tensioning plate (14) are fixedly provided in the return screen box (10); long holes (112) are respectively opened on both sides of the middle of the return screen box (10); both ends of the movable tensioning plate (14) pass through the long holes (112) to pass through the return screen box (10) and can move in the long holes (112) along the length direction of the long holes (112); the second bending parts (41) at both ends of the lower screen (40) are respectively hooked on the fixed positioning plate (13) and the movable tensioning plate (14) through the second bayonet (42); A fixed base plate (15) and a movable base plate (16) are fixedly provided on both sides of the return screen box (10), respectively. A first through hole is provided on the fixed base plate (15), and a first threaded hole is provided on the movable base plate (16) at a position opposite to the first through hole. A screw (17) passes through the first through hole and is screwed into the first threaded hole. The movable base plate (16) is attached to the side surface of the return screen box (10), and a through opening (18) for passing the end of the movable tensioning plate (14) is provided on the movable base plate (16).

2. The return screen according to claim 1, characterized in that: Extension plates (24) are provided on both sides of the motor mounting frame (21), and the extension plates (24) of the two motor mounting frames (21) on both sides are arranged opposite to each other, and the extension plates (24) on both sides are connected by connecting rods (25).

3. The return screen according to claim 1, characterized in that: The sleeve (22) is provided with a maintenance window at a middle position, and a window baffle (26) is detachably provided at a position corresponding to the maintenance window.

4. The return screen according to claim 1, characterized in that: Circular rings (27) coaxial with the sleeve (22) are respectively provided at both ends of the sleeve (22); one side of the circular ring (27) abuts and is connected to the motor mounting frame (21); and a reinforcing rib (28) is provided on the other side.

5. The return screen according to claim 1, characterized in that: There are a plurality of upper screens (30), which are arranged in sequence longitudinally and cover the top opening of the return screen box (10); Both sides of the upper screen (30) are respectively provided with first bending portions (31) bent upwards, and the first bending portions (31) form first bayonet openings (32); Tightening strips (11) are provided on both sides of the return screen box (10) at positions corresponding to the first bending portion (31); the cross section of the tightening strip (11) is U-shaped; one side of the tightening strip (11) is hooked into the first bayonet (32); and the tightening strip (11) is detachably provided on the return screen box (10).

6. The return screen according to claim 5, characterized in that: A supporting frame (12) is fixedly provided at the open top of the return screen box (10), and the upper screen (30) is placed on the supporting frame (12).

7. The return screen according to claim 1, characterized in that: The movable base plate (16) is attached to one side of the return material screen box (10) and is fixedly provided with a dustproof plate (19), and the dustproof plate (19) is attached to the side surface of the return material screen box (10); The dustproof plate (19) is provided with a through hole of the same size as the end of the movable tensioning plate (14) so ​​that the end of the movable tensioning plate (14) can pass through the dustproof plate (19), and the dustproof plate (19) covers the long hole (112).

8. The return screen according to claim 1, characterized in that: There are two lower screens (40), and the two lower screens (40) are arranged side by side in front and back; Two corresponding fixed positioning plates (13) are respectively arranged in the middle of the return material screen box (10), and the movable tensioning plates (14) are respectively arranged at both ends of the return material screen box (10). Maintenance windows are respectively provided at both ends of the return material screen box (10), and maintenance window baffles (110) are detachably provided at positions corresponding to the maintenance windows.

9. The return screen according to claim 1, characterized in that: Dust-proof baffles (111) are respectively provided at the bottom edges of the return screen box (10); the dust-proof baffles (111) are arranged inwardly inclined and have a certain degree of flexibility.

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