Aggregate screening device and method for road and bridge construction

Abstract

The invention relates to the technical field of building equipment, in particular to an aggregate screening device and method for road and bridge construction.The aggregate screening device comprises a screening hopper, the bottom of the screening hopper is elastically connected with a supporting mechanism through a damping spring, a vibration motor is further arranged on the outer side wall of the screening hopper, and the aggregate screening device further comprises a screening plate; a plurality of rows of screen holes are evenly formed in the surface of the screening plate in the width direction of the screening plate, and each row of screen holes are evenly distributed in the length direction of the screening plate at intervals. According to the stone screening device, the pushing mechanism is arranged, the pushing mechanism is provided with a plurality of pushing columns, the pushing columns can penetrate through the screening holes from bottom to top so as to push out stone blocks blocked in the screening holes, and compared with a traditional knocking vibration mode, the stone screening device cannot damage the screening device, and it can be guaranteed that the screening plate is in a smooth state for a long time.

Description

Technical Field

[0001] The invention relates to the technical field of construction equipment, and in particular to an aggregate screening device and method for road and bridge construction. Background Art

[0002] In the process of road and bridge construction, aggregate screening is a crucial link, and its screening effect directly affects the quality of subsequent concrete and the strength and stability of the entire road and bridge project. Most of the existing aggregate screening devices for road and bridge construction use screening nets to grade and screen aggregates. However, in actual use, the existing screening meshes are easily blocked. Since the aggregates used in road and bridge construction are of different sizes and shapes, during the screening process, some stones with irregular shapes or particle sizes close to the mesh size are very likely to get stuck in the mesh, resulting in a significant reduction in screening efficiency. When a blockage occurs, the stone that is stuck in the mesh is usually knocked and vibrated to make it fall off. However, this method has many disadvantages. For example, frequent knocking will damage the screening mechanism, which not only reduces the service life of the screening device, but also increases the equipment maintenance cost; and this method cannot completely remove the stones that are blocked in the mesh. Although some stones are loosened by knocking and vibration, some will still remain in the mesh, affecting the subsequent screening quality of aggregates, and thus affecting the engineering quality of road and bridge construction.

[0003] Therefore, it is urgent to design an aggregate screening device for road and bridge construction that can effectively avoid clogging of the screening mesh and will not cause damage to the screening mechanism. To this end, we propose an aggregate screening device and method for road and bridge construction to well solve the above-mentioned drawbacks. Summary of the invention

[0004] The object of the present invention is to provide an aggregate screening device and method for road and bridge construction, so as to solve the problems raised in the above-mentioned background technology.

[0005] The present invention is realized by the following technical scheme: an aggregate screening device for road and bridge construction, comprising a screening bucket, the bottom of which is elastically connected to a supporting mechanism via a shock-absorbing spring, and the outer side wall of the screening bucket is also provided with a vibration motor, and further comprising: A screening plate, the screening plate is horizontally arranged in the middle of the screening bucket, a plurality of rows of screening holes are evenly arranged on the surface of the screening plate along the width direction of the screening plate, and each row of screening holes is evenly spaced along the length direction of the screening plate; A pushing mechanism, which is movably arranged below the screening plate and has pushing columns corresponding to each row of screening holes, and the pushing columns can be raised and lowered in the height direction; A material pushing mechanism, wherein the material pushing mechanism is movably arranged above the screening plate, and the material pushing mechanism and the top pushing mechanism are fixedly connected; A driving assembly, which is arranged inside the screening hopper and is used to drive the pushing mechanism to slide along the length direction of the screening plate; Wherein, a discharge port is further opened on the side wall of the screening hopper, and the inner bottom surface of the discharge port is flush with the upper surface of the screening plate.

[0006] Optionally, slide rails are symmetrically arranged on the left and right sides of the inner wall of the screening hopper, and both sides of the screening plate are slidably matched with the two slide rails respectively.

[0007] Optionally, the pushing mechanism includes a pushing part, which is a cuboid rod-shaped structure. An installation cavity is opened inside the pushing part. A guiding column penetrates through the top surface of the pushing part, and the bottom end of the guiding column extends into the installation cavity. A pushing plate is arranged at the top end of the guiding column, and a plurality of pushing columns are evenly spaced on the upper surface of the pushing plate.

[0008] Optionally, a seat plate is arranged at the bottom end of the guiding column, a return spring is sleeved outside the guiding column, and both ends of the return spring are respectively abutted against the inner top surface of the installation cavity and the seat plate. A permanent magnet block is fixedly embedded on the bottom surface of the seat plate, and an electromagnet is arranged on the inner bottom surface of the installation cavity. When the electromagnet is energized, the opposite ends of the electromagnet and the permanent magnet block have the same magnetic poles; in the natural state, the return spring is in a compressed state.

[0009] Optionally, conductive columns are symmetrically arranged on the left and right sides of the bottom surface of the pushing part, and the two conductive columns are respectively connected to the two lead wires of the electromagnet; a plurality of conductive sheets are arranged on the left and right sides of the inner wall of the screening hopper, and the number of conductive sheets on each side corresponds to the number of rows of sieve holes. When the two conductive columns are respectively abutted against two conductive sheets on both sides, the pushing column is located directly below the corresponding sieve hole; A power supply is further arranged inside the screening hopper, and a plurality of conductive sheets on both sides of the screening hopper are respectively connected to the positive and negative poles of the power supply through wires.

[0010] Optionally, the pushing mechanism and the pushing mechanism are staggered in the horizontal direction, and the distance between the pushing mechanism and the discharge port is greater than the distance between the pushing mechanism and the discharge port; The pushing mechanism includes a pushing part, which is a cuboid rod-shaped structure. Oblique rods are arranged at both ends of the pushing part. A through hole for the oblique rod to pass through is opened on the slide rail, and the bottom end of the oblique rod passes through the through hole and is connected to the pushing part.

[0011] Optionally, two telescopic grooves are opened on the surface of the pushing part facing the discharge port. Pushing columns are movably arranged in the telescopic grooves. The outer ends of the two pushing columns are jointly connected to a pushing plate, and a pushing spring is connected between the inner ends of the pushing columns and the inner ends of the telescopic grooves; in the natural state, the pushing spring is in a compressed state.

[0012] Optionally, a towing rope is provided at the inner end of the pushing column. Threading channels for the towing rope to pass through are further opened at both ends of the pushing part, and a threading hole is also penetratingly opened on the inclined rod. Strip-shaped openings are formed at both ends of the pushing part. A movable column is arranged in each strip-shaped opening. The inner end of the movable column is fixedly connected to the seat plate. One end of the towing rope passes through the threading channel and the threading hole and is fixedly connected to the movable column.

[0013] Optionally, a movable gate is arranged in the discharge port. A gate opening for the movable gate to extend into is formed on the inner top surface of the discharge port. A gate rod is further arranged on the outer surface of the movable gate.

[0014] The present invention also provides an aggregate screening method applicable to the above-mentioned aggregate screening device, including the following steps: Pour the aggregate to be screened from above the screening hopper, and start the vibration motor. The vibration motor drives the screening hopper to vibrate, so that small-particle aggregates pass through the screening plate and are discharged from below the screening hopper, while large-particle aggregates remain above the screening plate. Take out the excess aggregate remaining on the screening plate through the discharge port. When many sieve holes on the screening plate are blocked, the driving assembly can be started at this time, and the driving assembly is used to drive the pushing mechanism to slide back and forth. When the pushing mechanism moves towards the discharge port side, the pushing column reciprocates up and down to push out the blocked aggregate. At the same time, the pushing mechanism pushes the pushed-out aggregate towards the discharge port side.

[0015] Compared with the prior art, the present invention provides an aggregate screening device and method for road and bridge construction, having the following beneficial effects: 1. The present invention is provided with a pushing mechanism. The pushing mechanism has a plurality of pushing columns. The pushing columns can pass through the sieve holes from bottom to top to push out the stones blocked in the sieve holes. Compared with the traditional knocking and vibrating method, the present invention will not damage the screening device and can ensure that the screening plate is always unblocked. 2. The driving assembly in the present invention can control the pushing mechanism to slide along the length direction of the screening plate. During the movement of the pushing mechanism, the pushing column can make a reciprocating up and down movement. Each time the pushing column moves to below the sieve hole, the pushing column automatically rises, thus realizing efficient hole cleaning operation. 3. The pushing mechanism of the present invention is provided with a pushing plate. Whenever the pushing column rises, the pushing plate can automatically extend a certain distance towards the discharge port side, so as to push the aggregate pushed out by the pushing column towards the discharge port side to prevent the aggregate from falling into the sieve hole again. Description of the Drawings

[0016] Figure 1 It is a structural schematic diagram of the present invention; Figure 2Schematic diagram of another state structure of the present invention; Figure 3 Schematic diagram of the jacking mechanism and the material pushing mechanism of the present invention; Figure 4 Cross-sectional view of the jacking mechanism and the material pushing mechanism of the present invention; Figure 5 Schematic diagram of the screening plate structure of the present invention; Figure 6 Schematic diagram of the split structure of the material pushing part of the present invention; Figure 7 is Figure 1 Magnified corresponding view at position A in Figure 8 is Figure 2 Magnified corresponding view at position B in Figure 9 is Figure 2 Magnified corresponding view at position C in Figure 10 is Figure 3 Magnified corresponding view at position D in

[0017] In the figure: 100, screening hopper; 101, vibration motor; 102, discharge port; 103, movable gate; 104, gate opening; 105, gate rod; 106, slide rail; 107, through hole; 108, conductive sheet; 200, support mechanism; 300, screening plate; 301, sieve hole; 400, jacking mechanism; 401, jacking part; 402, installation cavity; 403, guide post; 404, jacking plate; 405, seat plate; 406, return spring; 407, permanent magnet block; 408, electromagnet; 409, conductive column; 410, jacking column; 500, material pushing mechanism; 501, material pushing part; 502, inclined rod; 503, telescopic groove; 504, material pushing column; 505, material pushing spring; 506, material pushing plate; 507, traction rope; 508, threading channel; 509, threading hole; 510, strip-shaped opening; 511, movable column; 600, drive assembly. Specific embodiments

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0019] Embodiment 1: Please refer to Figure 1 - Figure 10, An aggregate screening device for road and bridge construction, including a screening hopper 100. The bottom of the screening hopper 100 is elastically connected to a support mechanism 200 through shock-absorbing springs. A vibration motor 101 is also provided on the outer side wall of the screening hopper 100. Among them, the screening hopper 100 is a funnel-shaped structure with a wider top and a narrower bottom. The support mechanism 200 includes several support columns. The tops of several support columns are jointly connected to a connecting frame in the shape of a rectangular square. Several shock-absorbing springs are connected between the connecting frame and the outer wall of the screening hopper 100. When the vibration motor 101 is started, it can drive the screening hopper 100 to generate high-frequency vibrations.

[0020] This embodiment also includes a screening plate 300, a top-pushing mechanism 400, and a pushing mechanism 500. Among them, the screening plate 300 is horizontally arranged in the middle part inside the screening hopper 100. A number of rows of screening holes 301 are evenly opened on the surface of the screening plate 300 along the width direction of the screening plate 300, and each row of screening holes 301 is evenly spaced along the length direction of the screening plate 300; that is, a number of rows of screening holes 301 are evenly spaced along the width direction of the screening plate 300, as Figure 5 shown, and in this embodiment, the aperture of the screening holes 301 is 3.5 - 5 cm, and the gap between two adjacent screening holes 301 does not exceed 3 cm.

[0021] The top-pushing mechanism 400 is movably arranged below the screening plate 300. The top-pushing mechanism 400 has top-pushing columns 410 corresponding to each row of screening holes 301 one by one, and the top-pushing columns 410 can move up and down in the height direction; the pushing mechanism 500 is movably arranged above the screening plate 300, and the pushing mechanism 500 and the top-pushing mechanism 400 are fixedly connected; among them, the top-pushing mechanism 400 is used to push the stones stuck in the screening holes 301 upward, and the pushing mechanism 500 is used to push the aggregate pushed out by the top-pushing mechanism 400 to one side.

[0022] Among them, a discharge port 102 is also opened on the side wall of the screening hopper 100. The inner bottom surface of the discharge port 102 is flush with the upper surface of the screening plate 300. When the screening is over, the staff can take out the excess aggregate on the screening plate 300 through the discharge port 102 to avoid the accumulation of excess aggregate on the screening plate 300. An activity gate 103 is arranged in the discharge port 102. A gate opening 104 for the activity gate 103 to extend into is opened on the inner top surface of the discharge port 102. A gate rod 105 is also arranged on the outer surface of the activity gate 103. In the natural state, due to the gravity of the activity gate 103, the activity gate 103 is always in a closed state, as Figure 9 shown; when the user holds the gate rod 105 and pulls it upward, the lower part of the activity gate 103 can be exposed to allow the stones to be discharged from the discharge port 102.

[0023] In the specific implementation process of this embodiment, the staff pour the aggregate stones to be screened into the interior of the screening hopper 100 from above the screening hopper 100. Under the action of the vibration motor 101, the screening hopper 100 vibrates at a high frequency, so that the stones with a particle diameter smaller than the sieve holes 301 pass through the screening plate 300 and are discharged from the bottom of the screening hopper 100.

[0024] In another embodiment of the present application, slide rails 106 are symmetrically arranged on the left and right sides of the inner wall of the screening hopper 100, and both sides of the screening plate 300 are respectively in sliding fit with the two slide rails 106. The pushing mechanism 400 includes a pushing part 401. The pushing part 401 is in the shape of a rectangular parallelepiped rod. An installation cavity 402 is formed inside the pushing part 401. A guiding column 403 penetrates through the top surface of the pushing part 401. The bottom end of the guiding column 403 extends into the installation cavity 402. A pushing plate 404 is arranged at the top end of the guiding column 403. A number of pushing columns 410 are evenly spaced on the upper surface of the pushing plate 404; that is, the guiding column 403 can move up and down vertically.

[0025] In addition, a seat plate 405 is arranged at the bottom end of the guiding column 403. A return spring 406 is sleeved outside the guiding column 403. The two ends of the return spring 406 are respectively abutted against the inner top surface of the installation cavity and the seat plate 405. A permanent magnet block 407 is fixedly embedded in the bottom surface of the seat plate 405. An electromagnet 408 is arranged on the inner bottom surface of the installation cavity 402. When the electromagnet 408 is energized, the opposite ends of the electromagnet 408 and the permanent magnet block 407 have the same magnetic poles; in the natural state, the return spring 406 is in a compressed state. It should be noted that when the electromagnet 408 is energized, due to the repulsion between like poles, the electromagnet 408 will apply an upward thrust to the guiding column 403, causing the guiding column 403 and the pushing columns 410 to move upward; when the electromagnet 408 is de-energized, under the action of the return spring 406 and gravity, the guiding column 403 will immediately retract.

[0026] Furthermore, conductive columns 409 are symmetrically arranged on the left and right sides of the bottom surface of the pushing part 401. The two conductive columns 409 are respectively connected to the two leads of the electromagnet 408; a number of conductive sheets 108 are arranged on the left and right sides of the inner wall of the screening hopper 100, and the number of conductive sheets 108 on each side corresponds to the number of rows of the sieve holes 301. When the two conductive columns 409 are respectively abutted against two conductive sheets 108 on both sides, the pushing columns 410 are located directly below the corresponding sieve holes 301; a power supply is also arranged in the screening hopper 100. A number of conductive sheets 108 on both sides of the screening hopper 100 are respectively connected to the positive and negative poles of the power supply through wires. And, a number of conductive sheets 108 on both sides are all aligned one by one. The conductive sheets 108 and the conductive columns 409 are both made of copper. Among them, the conductive sheets 108 are in an arched shape. The two ends of the conductive sheets 108 are connected to the screening hopper 100 and are insulated to prevent current from being transmitted to the screening hopper 100. In addition, the power supply uses a DC battery and the voltage is 12V.

[0027] When the pushing mechanism 400 approaches the discharging port 102, the conductive column 409 can intermittently contact several conductive sheets 108, and the pushing column 410 will reciprocate vertically; each time the pushing mechanism 400 moves to directly below the sieve hole 301, the pushing column 410 can move upward and penetrate through the sieve hole 301; when the pushing mechanism 400 is gradually misaligned with the sieve hole 301, the pushing column 410 will immediately retract to avoid rigid collision between the pushing column 410 and the inner wall of the sieve hole 301. It should be noted that when the electromagnet 408 is powered off, the top end of the pushing column 410 is lower than the lower surface of the screening plate 300.

[0028] Furthermore, this embodiment further includes a driving assembly 600. The driving assembly 600 is arranged inside the screening hopper 100 and is used to drive the pushing mechanism 400 to slide along the length direction of the screening plate 300; the driving assembly 600 adopts a linear slide, and the slide of the linear slide is fixedly connected to the side wall of the pushing part 401.

[0029] In summary, in the actual application process of this embodiment, in the initial state, the pushing mechanism 400 is located on the side far from the discharging port 102; after the vibration screening is completed, the staff can open the movable gate 103 and use tools to take out the excess large-grained aggregates on the screening plate 300. When it is necessary to clean the blocked aggregates in the sieve hole 301, the driving assembly 600 can be started to drive the pushing mechanism 400 to approach the discharging port 102 by means of the driving assembly 600. During the movement of the pushing mechanism 400 approaching the discharging port 102, since several conductive sheets 108 are evenly spaced, the conductive column 409 will also intermittently contact several conductive sheets 108, so that the pushing column 410 can reciprocate intermittently.

[0030] When the pushing column 410 rises, the top end of the pushing column 410 can penetrate through the sieve hole 301 to push the stones stuck in the sieve hole 301 upward, so as to ensure that several sieve holes 301 on the screening plate 300 are always unblocked, so as not to affect the screening efficiency.

[0031] In another embodiment of the present application, the pusher mechanism 500 and the pushing mechanism 400 are staggeredly distributed in the horizontal direction, and the distance between the pusher mechanism 500 and the discharge port 102 is greater than the distance between the pushing mechanism 400 and the discharge port 102; that is, the pushing mechanism 400 is closer to the pusher mechanism 500. The pusher mechanism 500 includes a pusher part 501, and the pusher part 501 is a rectangular parallelepiped rod-shaped structure. Oblique rods 502 are provided at both ends of the pusher part 501. A through hole 107 for the oblique rod 502 to pass through is opened on the slide rail 106. The bottom end of the oblique rod 502 passes through the through hole 107 and is connected to the pushing part 401. The two ends of the oblique rod 502 are fixedly connected to the pusher part 501 and the pushing part 401 by bolts respectively, and the oblique rod 502 is made of a rigid rod body, such as stainless steel material, to improve the connection strength between the pusher part 501 and the pushing part 401.

[0032] Further, two telescopic grooves 503 are opened on the surface of the pusher part 501 facing the discharge port 102. Pusher columns 504 are movably arranged in the telescopic grooves 503. A pusher plate 506 is commonly connected to the outer ends of the two pusher columns 504. A pusher spring 505 is connected between the inner ends of the pusher columns 504 and the inner ends of the telescopic grooves 503; in the natural state, the pusher spring 505 is in a compressed state; that is, the pusher spring 505 always exerts an outward thrust on the pusher plate 506.

[0033] In addition, a traction rope 507 is provided at the inner end of the pusher column 504. Threading channels 508 for the traction rope 507 to pass through are also opened at both ends of the pusher part 501. Threading holes 509 are also penetrated through the oblique rod 502; strip-shaped openings 510 are opened at both ends of the pushing part 401. Movable columns 511 are arranged in the strip-shaped openings 510. The inner ends of the movable columns 511 are fixedly connected to the seat plate 405. One end of the traction rope 507 passes through the threading channels 508 and the threading holes 509 and is fixedly connected to the movable column 511, and both traction ropes 507 are in a taut state.

[0034] It is worth mentioning that the threading channel 508 is L-shaped. The threading channel 508 includes a vertical section and a horizontal section. One end of the threading channel 508 is located on the side wall of the pusher part 501, and the other end of the threading channel 508 is located above the telescopic groove 503, and the corner of the threading channel 508 is chamfered. In addition, for the convenience of opening the threading channel 508, the pusher part 501 is composed of two upper and lower parts, such as Figure 6As shown, the upper and lower parts together form the horizontal section of the wire threading channel 508. Moreover, in this embodiment, the elastic force of the reset spring 406 is always greater than that of the pushing spring 505. When the electromagnet 408 is powered off from the energized state, the reset spring 406 can overcome the elastic force of the pushing spring 505 and pull the traction rope 507 downward, causing the pushing column 504 to retract; when the electromagnet 408 is energized, the electromagnet 408 can overcome the elastic force of the reset spring 406 and push the guiding column 403 upward. At the same time, the traction rope 507 is released, and then the pushing column 504 will extend outward.

[0035] Embodiment 2: An aggregate screening method is proposed in an embodiment of the present application, which is applicable to the aggregate screening device in Embodiment 1, and specifically includes the following steps: Pour the aggregate to be screened from above the screening hopper 100, and start the vibration motor 101. The vibration motor 101 drives the screening hopper 100 to vibrate, so that the small particle aggregates pass through the screening plate 300 and are discharged from below the screening hopper 100, while the large particle aggregates will remain above the screening plate 300; Take out the excess aggregate remaining on the screening plate 300 through the discharge port 102; When many sieve holes 301 on the screening plate 300 are blocked, the driving assembly 600 can be started at this time, and the driving assembly 600 is used to drive the pushing mechanism 400 to slide back and forth; When the pushing mechanism 400 moves toward the discharge port 102, the pushing column 410 reciprocates up and down to push out the blocked aggregate. At the same time, the pushing mechanism 500 pushes the pushed-out aggregate toward the discharge port 102. It should be noted that while the pushing column 410 moves upward, the pushing plate 506 will move toward the discharge port 102 to push the aggregate pushed out by the pushing column 410 to one side, as Figure 8 shown in the state. The function is to prevent the aggregate from falling into the sieve holes 301 again when the pushing column 410 retracts.

[0036] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the element.

[0037] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An aggregate screening device for road and bridge construction, including a screening hopper. The bottom of the screening hopper is elastically connected to a support mechanism through shock-absorbing springs. A vibration motor is also provided on the outer side wall of the screening hopper, and it is characterized in that, It further includes: A screening plate, which is horizontally arranged at the middle part inside the screening hopper. A number of rows of screening holes are evenly formed on the surface of the screening plate along the width direction of the screening plate, and each row of screening holes is evenly spaced along the length direction of the screening plate; A pushing mechanism, which is movably arranged below the screening plate. The pushing mechanism has pushing columns corresponding to each row of screening holes one by one, and the pushing columns can move up and down in the height direction; A material pushing mechanism, which is movably arranged above the screening plate, and is fixedly connected between the material pushing mechanism and the pushing mechanism; A driving component, which is arranged inside the screening hopper, and the driving component is used to drive the pushing mechanism to slide along the length direction of the screening plate; Among them, a discharge port is further formed on the side wall of the screening hopper, and the inner bottom surface of the discharge port is flush with the upper surface of the screening plate.

2. The aggregate screening device for road and bridge construction according to claim 1, characterized in that: Sliding rails are symmetrically arranged on the left and right sides of the inner wall of the screening hopper, and both sides of the screening plate are respectively in sliding fit with the two sliding rails.

3. An aggregate screening device for road and bridge construction according to claim 2, characterized in that: The pushing mechanism includes a pushing part, the pushing part is a cuboid rod-shaped structure. An installation cavity is formed inside the pushing part. A guiding column penetrates through the top surface of the pushing part, the bottom end of the guiding column extends into the installation cavity, a pushing plate is arranged at the top end of the guiding column, and a number of the pushing columns are evenly spaced on the upper surface of the pushing plate.

4. An aggregate screening device for road and bridge construction according to claim 3, characterized in that: A seat plate is arranged at the bottom end of the guiding column, a return spring is sleeved outside the guiding column, and both ends of the return spring are respectively abutted against the inner top surface of the installation cavity and the seat plate. A permanent magnet block is fixedly embedded on the bottom surface of the seat plate, and an electromagnet is arranged on the inner bottom surface of the installation cavity. When the electromagnet is powered on, the opposite ends of the electromagnet and the permanent magnet block have the same magnetic poles; in the natural state, the return spring is in a compressed state.

5. The aggregate screening device for road and bridge construction according to claim 4, characterized in that: Conductive columns are symmetrically arranged on the left and right sides of the bottom surface of the pushing part, and the two conductive columns are respectively connected to the two lead wires of the electromagnet; a number of conductive sheets are arranged on the left and right sides of the inner wall of the screening hopper, and the number of conductive sheets on each side corresponds to the number of rows of screening holes. When the two conductive columns are respectively abutted against the two conductive sheets on both sides, the pushing column is located directly below the corresponding screening hole; A power supply is further arranged inside the screening hopper, and a number of conductive sheets on both sides of the screening hopper are respectively connected to the positive and negative poles of the power supply through wires.

6. An aggregate screening device for road and bridge construction according to claim 4, characterized in that: The material pushing mechanism and the pushing mechanism are staggered in the horizontal direction, and the distance between the material pushing mechanism and the discharge port is greater than the distance between the pushing mechanism and the discharge port; The material pushing mechanism includes a material pushing part, the material pushing part is a cuboid rod-shaped structure. Oblique rods are arranged at both ends of the material pushing part, and through holes for the oblique rods to pass through are formed on the sliding rails. The bottom ends of the oblique rods pass through the through holes and are connected to the pushing part.

7. An aggregate screening device for road and bridge construction according to claim 6, characterized in that: Two telescopic grooves are formed on the surface of the material pushing part facing the discharge port. Pushing columns are movably arranged in the telescopic grooves. A pushing plate is jointly connected to the outer ends of the two pushing columns. A pushing spring is connected between the inner ends of the pushing columns and the inner ends of the telescopic grooves; in the natural state, the pushing spring is in a compressed state.

8. An aggregate screening device for road and bridge construction according to claim 7, characterized in that: A traction rope is arranged at the inner end of the pushing column, threading channels for the traction rope to pass through are further formed at both ends of the material pushing part, and threading holes are further formed through the oblique rods; Both ends of the pushing part are provided with strip-shaped openings, and movable columns are arranged in the strip-shaped openings. The inner ends of the movable columns are fixedly connected to the seat plate, and one end of the traction rope passes through the threading channel and the threading hole and is fixedly connected to the movable column.

9. The aggregate screening device for road and bridge construction according to claim 1, characterized in that: A movable gate is arranged in the discharge port. A gate opening for the movable gate to extend into is formed in the inner top surface of the discharge port, and a gate rod is further arranged on the outer surface of the movable gate.

10. An aggregate screening method, applicable to the aggregate screening device according to any one of claims 1-9, characterized in that, It includes the following steps: Pour the aggregate to be screened from above the screening hopper, and start the vibration motor. The vibration motor drives the screening hopper to vibrate, so that the small-particle aggregate passes through the screening plate and is discharged from below the screening hopper, while the large-particle aggregate remains above the screening plate. Take out the excess aggregate remaining on the screening plate through the discharge port. When many sieve holes on the screening plate are blocked, the driving assembly can be started at this time, and the driving assembly is used to drive the pushing mechanism to slide back and forth. When the pushing mechanism moves towards the discharge port side, the pushing column reciprocates up and down to push out the blocked aggregate, and at the same time the pushing mechanism pushes the pushed-out aggregate towards the discharge port side.

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