An aggregate screening device and method for road and bridge construction

Abstract

The present invention relates to the technical field of construction equipment, and specifically relates to an aggregate screening device and method 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. It also includes a screening plate. The screening plate 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. In the present invention, there is a pushing mechanism. The pushing mechanism has a number of pushing columns. The pushing columns can pass through the screening holes from bottom to top to push out the stones blocked in the screening holes. Compared with the traditional knocking and vibrating method, the present invention will not cause damage to the screening device and can ensure that the screening plate is always unobstructed for a long time.

Description

Technical Field

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

[0002] During the road and bridge construction process, the screening of aggregates 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 classify and screen aggregates. However, in actual use, the existing screening net holes are prone to blockage. Since the aggregates used in road and bridge construction vary in size and shape, during the screening process, some stones with irregular shapes or particle sizes close to the net hole size are extremely likely to get stuck in the net holes, resulting in a significant reduction in screening efficiency.

[0003] When blockage occurs, currently, the method of knocking and vibrating is usually used to make the stones blocked in the net holes fall off. However, this method has many drawbacks. For example, frequent knocking will damage the screening mechanism, not only reducing the service life of the screening device but also increasing the equipment maintenance cost; moreover, this method cannot completely remove the stones blocked in the net holes. Although some stones become loose under knocking and vibration, there will still be a part remaining in the net holes, affecting the subsequent screening quality of aggregates and thus the engineering quality of road and bridge construction.

[0004] Therefore, there is an urgent need to design an aggregate screening device for road and bridge construction that can effectively avoid blockage of the screening net holes and does not damage the screening mechanism. For this reason, we have proposed an aggregate screening device and method for road and bridge construction to well solve the above drawbacks. Summary of the Invention

[0005] The purpose of the present invention is to provide an aggregate screening device and method for road and bridge construction to solve the problems raised in the above background art.

[0006] The present invention is achieved through the following technical solutions: 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, and a vibration motor is also provided on the outer side wall of the screening hopper. It further includes:

[0007] A screening plate, the screening plate is horizontally arranged in the middle part inside the screening hopper, and 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;

[0008] A pushing mechanism, the pushing mechanism 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;

[0009] A pusher mechanism, which is movably arranged above the screening plate, and is fixedly connected between the pusher mechanism and the pushing mechanism;

[0010] A driving component, 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;

[0011] 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.

[0012] Optionally, 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.

[0013] Optionally, the pushing mechanism includes a pushing part, the pushing part 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, 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.

[0014] Optionally, a seat plate is arranged at the bottom end of the guiding column, a return spring is sleeved outside the guiding column, 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.

[0015] 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 leads 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;

[0016] 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.

[0017] Optionally, the pusher mechanism and the pushing mechanism are staggered in the horizontal direction, and the distance between the pusher mechanism and the discharge port is greater than the distance between the pushing mechanism and the discharge port;

[0018] The pusher mechanism includes a pusher part, the pusher part is a cuboid rod-shaped structure, inclined rods are arranged at both ends of the pusher part, through holes for the inclined rods to pass through are opened on the sliding rails, and the bottom ends of the inclined rods pass through the through holes and are connected to the pushing part.

[0019] Optionally, two telescopic grooves are formed in one side of the material pushing part facing the discharge port. A material pushing column is movably arranged in each telescopic groove. The outer ends of the two material pushing columns are jointly connected with a material pushing plate. A material pushing spring is connected between the inner end of the material pushing column and the inner end of the telescopic groove. In the natural state, the material pushing spring is in a compressed state.

[0020] Optionally, a towing rope is arranged at the inner end of the material pushing column. Threading channels for the towing rope to pass through are further formed at both ends of the material pushing part. A threading hole is also formed through the inclined rod.

[0021] Strip-shaped openings are formed at both ends of the top pushing part. A movable column is arranged in each strip-shaped opening. The inner end of the movable column is fixedly connected with the seat plate. One end of the towing rope passes through the threading channel and the threading hole and is fixedly connected with the movable column.

[0022] Optionally, 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. A gate rod is further arranged on the outer surface of the movable gate.

[0023] The present invention also provides an aggregate screening method applicable to the above-mentioned aggregate screening device, including the following steps:

[0024] 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.

[0025] Take out the redundant aggregate remaining on the screening plate through the discharge port.

[0026] When many screening 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 top pushing mechanism to slide back and forth.

[0027] When the top pushing mechanism moves towards the discharge port side, the top pushing columns reciprocate up and down to push out the blocked aggregate, and at the same time the material pushing mechanism pushes the pushed-out aggregate towards the discharge port side.

[0028] 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:

[0029] 1. The present invention is provided with a top pushing mechanism. The top pushing mechanism has a plurality of top pushing columns. The top pushing columns can pass through the screening holes from bottom to top to push out the stones blocked in the screening 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.

[0030] 2. The drive 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 perform reciprocating lifting motion. Each time when the pushing column moves to below the screening hole, the pushing column automatically rises, thus realizing efficient hole cleaning operation.

[0031] 3. The pushing mechanism of the present invention has a pushing plate. Whenever the pushing column rises, the pushing plate can automatically extend a certain distance towards the discharge port side, thereby pushing the aggregate pushed out by the pushing column towards the discharge port side to prevent the aggregate from falling into the screening hole again. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic structural diagram of the present invention;

[0033] Figure 2 is a schematic structural diagram of another state of the present invention;

[0034] Figure 3 is a schematic diagram of the pushing mechanism and the material pushing mechanism of the present invention;

[0035] Figure 4 is a cross-sectional view of the pushing mechanism and the material pushing mechanism of the present invention;

[0036] Figure 5 is a schematic structural diagram of the screening plate of the present invention;

[0037] Figure 6 is a schematic diagram of the split structure of the material pushing part of the present invention;

[0038] Figure 7 is Figure 1 the enlarged corresponding view at A in

[0039] Figure 8 is Figure 2 the enlarged corresponding view at B in

[0040] Figure 9 is Figure 2 the enlarged corresponding view at C in

[0041] Figure 10 is Figure 3 the enlarged corresponding view at D in

[0042] 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 holes; 400, pushing mechanism; 401, pushing part; 402, installation cavity; 403, guiding column; 404, pushing plate; 405, seat plate; 406, return spring; 407, permanent magnet block; 408, electromagnet; 409, conductive column; 410, pushing 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, towing rope; 508, threading channel; 509, threading hole; 510, strip-shaped opening; 511, movable column; 600, driving assembly. Specific implementation mode

[0043] 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.

[0044] 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 the several support columns are commonly connected to a connecting frame in the shape of a rectangular square frame. 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.

[0045] This embodiment also includes a screening plate 300, a pushing mechanism 400, and a material pushing mechanism 500. Among them, the screening plate 300 is horizontally arranged in the middle part inside the screening hopper 100. A plurality of rows of sieve 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 sieve holes 301 is evenly spaced along the length direction of the screening plate 300; that is, several rows of sieve 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 sieve holes 301 is 3.5 - 5 cm, and the gap between two adjacent sieve holes 301 does not exceed 3 cm.

[0046] The pushing mechanism 400 is movably arranged below the screening plate 300. The pushing mechanism 400 has pushing columns 410 corresponding one by one to each row of screening holes 301, and the pushing columns 410 can move up and down in the height direction. The feeding mechanism 500 is movably arranged above the screening plate 300, and the feeding mechanism 500 and the pushing mechanism 400 are fixedly connected. Among them, the pushing mechanism 400 is used to push the stones stuck in the screening holes 301 upward, and the feeding mechanism 500 is used to push the aggregates pushed out by the pushing mechanism 400 to one side.

[0047] Among them, a discharge port 102 is also opened on the side wall of the screening hopper 100, and the inner bottom surface of the discharge port 102 is flush with the upper surface of the screening plate 300. After screening, the staff can take out the excess aggregates on the screening plate 300 through the discharge port 102 to avoid the accumulation of excess aggregates on the screening plate 300. A movable gate 103 is arranged in the discharge port 102, a gate opening 104 for the movable gate 103 to extend into is opened on the inner top surface of the discharge port 102, and a gate rod 105 is also arranged on the outer surface of the movable gate 103. In the natural state, due to the gravity of the movable gate 103, the movable gate 103 is always in the closed state, as Figure 9 shown; when the user holds the gate rod 105 and pulls it upward, the lower part of the movable gate 103 can be exposed to allow the stones to be discharged from the discharge port 102.

[0048] In the specific implementation process of this embodiment, the staff pours 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 screening holes 301 pass through the screening plate 300 and are discharged from the bottom of the screening hopper 100.

[0049] 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 slidably matched with the two slide rails 106. The pushing mechanism 400 includes a pushing part 401. The pushing part 401 is a cuboid rod-shaped structure. An installation cavity 402 is opened inside the pushing part 401. A guiding column 403 penetrates through the top surface of the pushing part 401, and 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 plurality 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.

[0050] In addition, a seat plate 405 is provided at the bottom end of the guide post 403. A return spring 406 is sleeved outside the guide post 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 provided 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 guide post 403, causing the guide post 403 and the push post 410 to move upward. When the electromagnet 408 is de-energized, under the action of the return spring 406 and gravity, the guide post 403 will immediately retract.

[0051] Furthermore, conductive posts 409 are symmetrically provided on the left and right sides of the bottom surface of the pushing part 401. The two conductive posts 409 are respectively connected to the two leads of the electromagnet 408. A plurality of conductive sheets 108 are provided 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 posts 409 are respectively abutted against two conductive sheets 108 on both sides, the push post 410 is located directly below the corresponding sieve hole 301. A power supply is also provided in the screening hopper 100. A plurality 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 plurality of conductive sheets 108 on both sides are aligned one by one. The conductive sheets 108 and the conductive posts 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 with a voltage of 12V.

[0052] When the pushing mechanism 400 approaches the discharge port 102, the conductive posts 409 can intermittently abut against a plurality of conductive sheets 108, and the push post 410 will reciprocate up and down vertically. Each time when the pushing mechanism 400 moves to directly below the sieve hole 301, the push post 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 push post 410 will immediately retract to avoid rigid collision between the push post 410 and the inner wall of the sieve hole 301. And it should be noted that when the electromagnet 408 is de-energized, the top end of the push post 410 is lower than the lower surface of the screening plate 300.

[0053] Furthermore, this embodiment further includes a driving assembly 600. The driving assembly 600 is provided inside the screening hopper 100. The driving assembly 600 is used to drive the pushing mechanism 400 to slide along the length direction of the screening plate 300. The driving assembly 600 uses a linear slide. The slide of the linear slide is fixedly connected to the side wall of the pushing part 401.

[0054] In summary, in the actual application process of this embodiment, in the initial state, the jacking mechanism 400 is located on the side away from the discharge 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-sized aggregate on the screening plate 300. When it is necessary to clean the blocked aggregate in the sieve holes 301, the driving assembly 600 can be started, and the driving assembly 600 is used to drive the jacking mechanism 400 to approach the discharge port 102. During the movement of the jacking mechanism 400 approaching the discharge port 102, since a plurality of conductive sheets 108 are evenly spaced, the conductive column 409 will also intermittently contact the plurality of conductive sheets 108, so that the jacking column 410 can intermittently reciprocate up and down.

[0055] When the jacking column 410 rises, the top end of the jacking column 410 can penetrate through the sieve hole 301 to push the stone stuck in the sieve hole 301 upward, so as to ensure that a plurality of sieve holes 301 on the screening plate 300 are always unblocked, so as not to affect the screening efficiency.

[0056] In another embodiment of the present application, the pushing mechanism 500 and the jacking mechanism 400 are staggeredly distributed in the horizontal direction, and the distance between the pushing mechanism 500 and the discharge port 102 is greater than the distance between the jacking mechanism 400 and the discharge port 102; that is, the jacking mechanism 400 is closer to the pushing mechanism 500. The pushing mechanism 500 includes a pushing part 501, and the pushing part 501 is a cuboid rod-shaped structure. Oblique rods 502 are provided at both ends of the pushing 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 jacking part 401. The two ends of the oblique rod 502 are respectively fixedly connected to the pushing part 501 and the jacking part 401 by bolts, and the oblique rod 502 is made of a rigid rod body, such as stainless steel, to improve the connection strength between the pushing part 501 and the jacking part 401.

[0057] Further, two telescopic grooves 503 are opened on the surface of the pushing part 501 facing the discharge port 102. Pushing columns 504 are movably arranged in the telescopic grooves 503. The outer ends of the two pushing columns 504 are commonly connected to a pushing plate 506. A pushing spring 505 is connected between the inner ends of the pushing columns 504 and the inner ends of the telescopic grooves 503. In the natural state, the pushing spring 505 is in a compressed state; that is, the pushing spring 505 always exerts an outward thrust on the pushing plate 506.

[0058] In addition, a towing rope 507 is provided at the inner end of the pusher column 504. Threading channels 508 for the towing rope 507 to pass through are also formed at both ends of the pusher part 501, and a threading hole 509 is formed through the inclined rod 502. Strip-shaped openings 510 are formed at both ends of the pushing part 401. A movable column 511 is arranged in the strip-shaped openings 510. The inner end of the movable column 511 is fixedly connected to the seat plate 405. One end of the towing rope 507 passes through the threading channels 508 and the threading hole 509 and is fixedly connected to the movable column 511, and both towing ropes 507 are in a taut state.

[0059] 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 forming the threading channel 508, the pusher part 501 is composed of an upper part and a lower part. As Figure 6 shown, the upper and lower parts together form the horizontal section of the threading channel 508. And in this embodiment, the elastic force of the return spring 406 is always greater than the elastic force of the pusher spring 505. When the electromagnet 408 is powered off from the energized state, the return spring 406 can overcome the elastic force of the pusher spring 505 and pull the towing rope 507 downward, so that the pusher column 504 retracts; when the electromagnet 408 is energized, the electromagnet 408 can overcome the elastic force of the return spring 406 and push the guide column 403 upward. At the same time, the towing rope 507 is released, and then the pusher column 504 will extend outwards.

[0060] Embodiment 2: An aggregate screening method proposed in an embodiment of the present application is applicable to the aggregate screening device in Embodiment 1, and specifically includes the following steps:

[0061] 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 aggregate passes through the screening plate 300 and is discharged from below the screening hopper 100, while the large-particle aggregate remains above the screening plate 300;

[0062] Take out the excess aggregate remaining on the screening plate 300 through the discharge port 102;

[0063] 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;

[0064] When the jacking mechanism 400 moves towards the discharging port 102 side, the jacking column 410 reciprocates up and down to eject the blocked aggregate. At the same time, the material pushing mechanism 500 pushes the ejected aggregate towards the discharging port 102 side. It should be noted that when the jacking column 410 moves upward, the pushing plate 506 will move towards the discharging port 102 side to push the aggregate ejected by the jacking 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 jacking column 410 retracts.

[0065] 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 actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising 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 "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0066] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. 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, comprising 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, characterized in that, It further includes: A screening plate, which is horizontally arranged at the middle part inside the screening hopper. A plurality 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 top-pushing mechanism, which is movably arranged below the screening plate. The top-pushing mechanism has top-pushing columns corresponding to each row of screening holes one by one, and the top-pushing columns can move up and down in the height direction; A material-pushing mechanism, which 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 the driving assembly is used to drive the top-pushing mechanism to slide along the length direction of the screening plate; Wherein, 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; Sliding rails are symmetrically arranged on the left and right sides of the inner wall of the screening hopper, and the two sides of the screening plate are respectively in sliding fit with the two sliding rails; The top-pushing mechanism includes a top-pushing part, the top-pushing part is a cuboid rod-shaped structure. An installation cavity is formed inside the top-pushing part. A guiding column penetrates through the top surface of the top-pushing part, the bottom end of the guiding column extends into the installation cavity, a top-pushing plate is arranged at the top end of the guiding column, and a plurality of the top-pushing columns are evenly spaced on the upper surface of the top-pushing plate; A seat plate is arranged at the bottom end of the guiding column, a return spring is sleeved outside the guiding column, and the two 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; The material-pushing mechanism and the top-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 top-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. Through holes for the oblique rods to pass through are formed on the sliding rails, and the bottom ends of the oblique rods pass through the through holes and are connected to the top-pushing part; 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; 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; Strip-shaped openings are formed at both ends of the top-pushing part. Moving columns are arranged in the strip-shaped openings. The inner ends of the moving columns are fixedly connected to the seat plate, and one end of the traction rope passes through the threading channels and the threading holes and is fixedly connected to the moving columns.

2. The aggregate screening device for road and bridge construction according to claim 1, wherein: On the left and right sides of the bottom surface of the pushing part, conductive columns are symmetrically arranged, and the two conductive columns are respectively connected to the two leads of the electromagnet; on the left and right sides of the inner wall of the screening hopper, a plurality of conductive sheets are arranged, 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 in contact with two conductive sheets on both sides, the pushing column is located directly below the corresponding sieve hole; A power supply is also arranged in the screening hopper, and a plurality of conductive sheets located on both sides of the screening hopper are respectively connected to the positive and negative electrodes of the power supply through wires.

3. An 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 opened on the inner top surface of the discharge port, and a gate rod is further arranged on the outer surface of the movable gate.

4. An aggregate screening method, applicable to the aggregate screening device according to any one of claims 1-3, 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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