Multistage anti-blocking vibrating screen for asphalt pavement milling material

Abstract

This invention relates to the field of construction waste recycling technology, specifically to a multi-stage anti-clogging vibrating screen for asphalt pavement milling materials. The screen includes a screen box containing a first screening component, a limiting component, and a clearing mechanism. The first screening component includes multiple cantilever screen bars. The limiting component includes a limiting plate with multiple limiting grooves. A clearing mechanism is located beside the limiting component, comprising a drive component and rake teeth. An air outlet is located beside the clearing mechanism. The rake teeth insert into the gaps between the multiple cantilever screen bars to break the mechanical jamming of the material. Simultaneously, the directional airflow from the air outlet continuously cools the core area of ​​frictional heat generation between the rake teeth and the limiting grooves, strictly controlling the contact surface temperature below the asphalt softening point. This physical breaking combined with temperature control fundamentally eliminates the problem of screen clogging caused by asphalt melting and stringing due to frictional heat.

Description

Technical Field

[0001] This invention relates to the field of construction waste recycling technology, specifically to a multi-stage anti-clogging vibrating screen for asphalt pavement milling material. Background Technology

[0002] Reclaimed asphalt pavement (RAP) is waste asphalt mixture generated during road maintenance. To achieve resource recycling, RAP typically requires crushing and screening to obtain recycled aggregates of different particle sizes. However, RAP differs fundamentally from ordinary sand and gravel aggregates due to its surface being covered with an aged asphalt film, exhibiting strong adhesion and heat sensitivity. Currently, screening of RAP mainly employs traditional circular vibrating screens or vibrating screens with string patterns. Because RAP often contains irregularly shaped particles, either flaky or agglomerated, these particles easily become trapped in the screen mesh (especially the strip-shaped mesh), forming a wedging state. Existing vibrating screens, relying solely on the excitation force of the screen box itself, often struggle to eject these wedging particles, leading to a rapid reduction in the effective screening area and a significant decrease in screening efficiency. To address the clogging problem, some existing technologies have developed equipment with active unclogging devices, which require frequent insertion into the screen holes and friction with the screen bars during operation. The asphalt in RAP is extremely sensitive to temperature. Under continuous high-frequency friction, the local temperature at the metal contact surface rises rapidly. Once it exceeds the softening point of the asphalt, the originally brittle asphalt softens and becomes stringy, sticking the unblocking device to the screen bar like glue. This not only leads to unblocking failure but can even burn out the drive motor or break the unblocking rod. Existing technologies generally neglect the problem of asphalt softening caused by frictional heat. Summary of the Invention

[0003] To address the aforementioned problems, a multi-stage anti-clogging vibrating screen for asphalt pavement milling materials is provided. This screen breaks up the mechanical blockage of materials by inserting rake teeth into the gaps between multiple cantilever screen bars. Simultaneously, directional airflow from the outlet continuously cools the core friction-heating area between the rake teeth and the limiting groove, strictly controlling the contact surface temperature below the asphalt softening point. This combination of physical breaking and temperature control fundamentally eliminates the problem of screen clogging caused by asphalt melting and stringing due to frictional heat.

[0004] To address the problems of existing technologies, this invention provides a multi-stage anti-clogging vibrating screen for asphalt pavement milling materials, comprising a screen box for driving the material to move along the screening direction, a first screening component at the top of the screen box, the first screening component including multiple cantilever screen bars arranged inclined along the material flow direction, each cantilever screen bar having a fixed end fixedly connected to the screen box and a free end extending along the material flow direction; a limiting component is provided inside the screen box at the free end of the cantilever screen bar, the limiting component including a limiting plate with multiple limiting grooves, the free end of the cantilever screen bar being intermittently inserted into the limiting groove to limit the lateral swing of the cantilever screen bar; a clearing mechanism is provided beside the limiting component, the clearing mechanism including a driving component and rake teeth, the rake teeth being configured to reciprocate under the drive of the driving component to intermittently insert into the gap between the cantilever screen bar and the limiting groove; an air outlet is provided beside the clearing mechanism, the air outlet being configured to spray airflow toward the area where the rake teeth and the limiting groove are engaged.

[0005] Preferably, the drive assembly includes a rotating shaft, an eccentric wheel, and a connecting rod; the rotating shaft is rotatably disposed inside the screen box, the eccentric wheel is sleeved on the rotating shaft, the bottom end of the connecting rod is sleeved on the eccentric wheel through a bearing, and the top end of the connecting rod extends to the limiting assembly and is connected to the rake teeth; when the eccentric wheel rotates, the connecting rod drives the rake teeth to reciprocate.

[0006] Preferably, the connecting rod has a waist-shaped guide groove in the middle, and the side wall of the screen box is provided with a positioning pin that passes through the guide groove; the configuration is to limit the movement of the connecting rod by using the positioning pin, so that the rake teeth move along an elliptical trajectory, the elliptical trajectory including a lifting section that inserts into the gap and a pushing section that swings in the discharge direction.

[0007] Preferably, the unblocking mechanism further includes a mounting frame connected to the top of the connecting rod; the rake teeth are multiple, and the multiple rake teeth are spaced apart and independently installed on the mounting frame, with the positions of the rake teeth corresponding one-to-one with the positions of the limiting grooves.

[0008] Preferably, the top of the rake teeth is conical to guide the free end gap of the inserted cantilever screen bar; the side of the rake teeth facing the material outflow direction is provided with a wedge-shaped pushing surface, which is configured to use the wedge-shaped pushing surface to split and push the material in the gap.

[0009] Preferably, the unblocking mechanism further includes a scraper plate fixedly connected below the retraction path of the rake teeth along the elliptical trajectory. The scraper plate has a scraping groove that matches the rake teeth, and is configured to scrape off the adhering material on the surface of the rake teeth by using the edge of the scraping groove when the rake teeth retract along the elliptical trajectory and pass through the scraping groove.

[0010] Preferably, a waste collection hopper is provided below the scraper; the scraper is arranged at an angle, with its lower end extending above the waste collection hopper, configured to guide the scraped-off adhering material into the waste collection hopper.

[0011] Preferably, a second screening component is provided directly below the first screening component for receiving and screening the undersize material passing through the gap between the cantilever screen bars; a fine material collection hopper is provided below the second screening component, and a partition is provided between the fine material collection hopper and the waste material collection hopper.

[0012] Preferably, the cantilever screen bar is made of wear-resistant steel bar with a rectangular or trapezoidal cross section; the clearance between the free end of the cantilever screen bar and the limiting groove is less than the minimum effective screening particle size of the asphalt milling material.

[0013] Preferably, there are two air outlets, which are located at both ends of the width direction of the limiting plate.

[0014] The advantages of this invention compared to the prior art are: 1. This invention breaks down the mechanical jamming of materials by inserting rake teeth into the gaps between multiple cantilever screen bars; simultaneously, it utilizes directional airflow from the outlet to continuously cool the core area of ​​frictional heat generation between the rake teeth and the limiting groove, strictly controlling the contact surface temperature below the softening point of the asphalt. This physical breaking combined with temperature control fundamentally eliminates the problem of screen clogging caused by the melting and stringing of asphalt due to frictional heat.

[0015] 2. This invention, through the arrangement of a rotating shaft, eccentric wheel, and connecting rod, utilizes a rotating guide rod mechanism to impart an elliptical motion trajectory to the rake teeth, involving vertical lifting, horizontal pushing, and retraction. This trajectory not only loosens tightly wedged materials but also actively pushes large, sticky agglomerates away from the screen surface using the horizontal component force, improving discharge efficiency. Simultaneously, the limiting component cleverly balances the contradiction between the high screen penetration rate of the cantilever screen bars' secondary vibration at the free end and structural stability, effectively preventing fatigue fracture caused by lateral swaying of the cantilever screen bars.

[0016] 3. This invention solves the secondary pollution and maintenance problems caused by sticky sludge. By coordinating the scraper and rake tooth retraction trajectory, the sludge on the rake tooth surface is peeled off in real time using the equipment's own cyclical motion, achieving maintenance-free operation of key components. Simultaneously, the baffle completely isolates the waste material and sludge discharged from the unblocking process from the fine finished material screened from the lower layer, ensuring that contaminated material does not mix with the clean material and strictly guaranteeing the gradation quality of the recycled asphalt mixture. Attached Figure Description

[0017] Figure 1 This is a three-dimensional structural diagram of a multi-stage anti-clogging vibrating screen for milling asphalt pavement materials.

[0018] Figure 2 This is a front view of a multi-stage anti-clogging vibrating screen for milling asphalt pavement materials.

[0019] Figure 3 This is a top view of a multi-stage anti-clogging vibrating screen for milling asphalt pavement materials.

[0020] Figure 4 This is a schematic diagram of the cross-sectional structure of a multi-stage anti-clogging vibrating screen for asphalt pavement milling material when the rake teeth are located in the lifting section.

[0021] Figure 5 This is a schematic diagram of the cross-sectional structure of a multi-stage anti-clogging vibrating screen for asphalt pavement milling material when the rake teeth are located in the pushing section.

[0022] Figure 6 This is a schematic diagram of the cross-sectional structure of a multi-stage anti-clogging vibrating screen for asphalt pavement milling material when the rake teeth are located in the retraction section.

[0023] Figure 7 This is a schematic diagram of the cross-sectional structure of a multi-stage anti-clogging vibrating screen for asphalt pavement milling material when the rake teeth are located in the avoidance section.

[0024] Figure 8 This is a cross-sectional three-dimensional structural diagram of a multi-stage anti-clogging vibrating screen for asphalt pavement milling materials. Figure 1 .

[0025] Figure 9 yes Figure 8 Enlarged view of point A in the middle.

[0026] Figure 10 yes Figure 8 Enlarged view of point B in the middle.

[0027] Figure 11 This is a cross-sectional three-dimensional structural diagram of a multi-stage anti-clogging vibrating screen for asphalt pavement milling materials. Figure 2 .

[0028] The diagram is labeled as follows: 1. Screen box; 11. Limiting assembly; 111. Limiting plate; 112. Limiting groove; 12. Unblocking mechanism; 121. Drive assembly; 1211. Rotating shaft; 1212. Eccentric wheel; 1213. Connecting rod; 12131. Guide groove; 12132. Positioning pin; 122. Rake teeth; 123. Mounting frame; 124. Scraper; 1241. Scraper trough; 125. Waste collection hopper; 13. Air outlet; 2. First screening assembly; 21. Cantilever screen bar; 22. Second screening assembly; 221. Fine material collection hopper; 222. Baffle plate. Detailed Implementation

[0029] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0030] like Figures 1 to 4 , Figures 8 to 10 As shown: A multi-stage anti-clogging vibrating screen for asphalt pavement milling material includes a screen box 1 for driving the material to move along the screening direction. A first screening component 2 is provided on the top of the screen box 1. The first screening component 2 includes multiple cantilever screen bars 21 arranged inclined along the material flow direction. Each cantilever screen bar 21 has a fixed end fixedly connected to the screen box 1 and a free end extending along the material flow direction. A limit component 11 is provided inside the screen box 1 at the free end of the cantilever screen bars 21. The limit component 11 includes a limit plate 111 with multiple limit grooves 112. The free end of the cantilever screen bar 21 is interposed in the limiting groove 112 to restrict the lateral swing of the cantilever screen bar 21; a clearing mechanism 12 is provided on the side of the limiting component 11, the clearing mechanism 12 includes a driving component 121 and rake teeth 122, the rake teeth 122 are configured to reciprocate under the drive of the driving component 121 to intermittently insert into the gap between the cantilever screen bar 21 and the limiting groove 112; an air outlet 13 is provided on the side of the clearing mechanism 12, the air outlet 13 is configured to spray airflow toward the area where the rake teeth 122 and the limiting groove 112 are mated.

[0031] In asphalt pavement recycling processes, milled asphalt often has strong adhesion due to the presence of aged asphalt, and it easily generates heat during screening friction, causing the asphalt to soften, thus sticking to the screen or accumulating at the end of the screening process. In this embodiment, the screen box 1 vibrates under the drive of a vibration source, and the material enters the first screening component 2 at the top of the screen box 1. By suspending the cantilever screen bar 21 with one end fixed and the other end free, the secondary vibration effect of the free end (with an amplitude greater than that of the screen box 1) is used to throw the material up, preventing adhesion. To prevent the cantilever from being too long and causing lateral swaying or breakage, a limiting plate 111 is set at the free end of the cantilever screen bar 21, and the end of the cantilever screen bar 21 is inserted into the limiting groove 112 of the limiting plate 111, retaining only the freedom of vertical vibration. When large clumps of material slide to the end of the screening (i.e., the area where the cantilever screen bar 21 and the limiting groove 112 meet) and become stuck, the unblocking mechanism 12 is activated. Driven by the drive assembly 121, the rake teeth 122 reciprocate, intermittently inserting into the mating gap between the free end of the cantilever screen bar 21 and the limiting groove 112, forcibly pushing out the jammed material. Simultaneously, the air outlet 13 of the air-cooling mechanism continuously sprays high-speed airflow into the friction mating area between the rake teeth 122 and the limiting groove 112, using air cooling to remove the heat generated by mechanical friction. The cantilever screen bar 21 improves the screening throughput, and combined with the active rake teeth 122 for unclogging, it solves the mechanical jamming problem. The air-cooling system also controls the temperature of the rake teeth 122 and the limiting groove 112, keeping the temperature below the softening point of the asphalt, preventing the asphalt from melting and forming fibers due to frictional heat, and ensuring the long-term stable operation of the unclogging mechanism 12. The limiting assembly 11 effectively restricts the harmful lateral sway of the cantilever screen bar 21, extending the service life of the screen bar.

[0032] like Figures 4 to 11 As shown: The drive assembly 121 includes a rotating shaft 1211, an eccentric wheel 1212, and a connecting rod 1213; the rotating shaft 1211 is rotatably disposed inside the screen box 1, the eccentric wheel 1212 is sleeved on the rotating shaft 1211, the bottom end of the connecting rod 1213 is sleeved on the eccentric wheel 1212 through a bearing, and the top end of the connecting rod 1213 extends to the limiting assembly 11 and is connected to the rake teeth 122; when the eccentric wheel 1212 rotates, the connecting rod 1213 drives the rake teeth 122 to reciprocate.

[0033] The rotating shaft 1211 is preferably driven by a motor. The motor drives the rotating shaft 1211 to rotate, allowing it to rotatably mount horizontally within the screen box 1. Simultaneously, an eccentric wheel 1212 is securely fitted onto the rotating shaft 1211, and the bottom end of the connecting rod 1213 is fitted onto the outer ring of the eccentric wheel 1212 via a heavy-duty bearing. When the rotating shaft 1211 drives the eccentric wheel 1212 to rotate, the center of the eccentric wheel 1212 rotates around the shaft, thereby driving the connecting rod 1213 to move up and down in a corresponding reciprocating motion. The top end of the connecting rod 1213 extends directly to the limiting assembly 11 and connects to the rake teeth 122. The arrangement of the eccentric wheel 1212 and the connecting rod 1213 provides a strong lifting force sufficient to break up hardened or wedged asphalt clumps.

[0034] like Figures 4 to 11 As shown: The connecting rod 1213 has a waist-shaped guide groove 12131 in the middle, and the side wall of the screen box 1 is provided with a positioning pin 12132 passing through the guide groove 12131; the configuration is to limit the movement of the connecting rod 1213 by using the positioning pin 12132, so that the rake teeth 122 move along an elliptical trajectory, the elliptical trajectory including a lifting section for inserting into the gap and a pushing section for swinging in the discharge direction.

[0035] If the rake teeth 122 only move in a straight up-and-down motion, they can only loosen the stuck material, but the material may get stuck again after falling, making it impossible to discharge effectively. By opening a waist-shaped guide groove 12131 in the middle of the connecting rod 1213 and fixing a positioning pin 12132 on the side wall of the screen box 1, with the positioning pin 12132 passing through the guide groove 12131, when the bottom of the connecting rod 1213 rotates with the eccentric wheel 1212, the middle part of the connecting rod 1213 is restricted by the pin and can only swing and slide. As a result, the rake teeth 122 at the top of the connecting rod 1213 will form a specific elliptical trajectory, which is divided into a lifting section, a pushing section, a retraction section, and a clearance section. First, the rake teeth 122 enter the lifting section, where they vertically insert into the gaps of the cantilever screen bars 21, forcibly breaking the wedging state of the material. Then, the rake teeth 122 enter the pushing section, where they swing towards the material discharge direction near the highest point, pushing the material outward. Finally, the rake teeth 122 reach the retraction and reset sections, moving downward and backward to avoid the material falling later, forming an elliptical motion trajectory. This gives the rake teeth 122 the dual functions of cleaning and conveying. By utilizing the horizontal displacement of the pushing section, large, sticky agglomerates that are difficult to screen are forcibly pushed away from the screen surface, completely solving the problem of accumulation at the end of the screen surface.

[0036] like Figures 4 to 11As shown: The unblocking mechanism 12 also includes a mounting frame 123, which is connected to the top of the connecting rod 1213; there are multiple rake teeth 122, and the multiple rake teeth 122 are spaced apart and independently installed on the mounting frame 123, and the positions of the rake teeth 122 correspond one-to-one with the positions of the limiting grooves 112.

[0037] In actual production, the wear degree of the screen bars varies at different locations, and the rake teeth 122 directly collide with the hard milled material, making them vulnerable parts. If the rake teeth 122 and the connecting rod 1213 were an integral structure, replacement would be extremely difficult. In this embodiment, a horizontal mounting bracket 123 is connected to the top of the connecting rod 1213. Multiple rake teeth 122 are independently fixed to the mounting bracket 123 with bolts or pins according to the one-to-one spacing corresponding to the limiting grooves 112. This enables independent disassembly and replacement of the rake teeth 122. When a single rake tooth 122 is worn or damaged, it is not necessary to disassemble the entire large drive mechanism; only the damaged single tooth needs to be replaced, significantly reducing maintenance costs and downtime.

[0038] like Figures 4 to 9 As shown: the top of the rake tooth 122 is conical and is used to guide the free end gap of the inserted cantilever screen bar 21; the rake tooth 122 is provided with a wedge-shaped pushing surface on the side facing the material outflow direction, which is configured to use the wedge-shaped pushing surface to generate a splitting and pushing effect on the material in the gap.

[0039] When the rake teeth 122 are inserted into the gap between the screen bars at high speed, misalignment can easily occur, leading to impact; and the sticky asphalt can easily adhere to flat surfaces. By setting the top of the rake teeth 122 to a pointed cone shape, it plays a guiding and correcting role during insertion. The pointed cone structure improves the fault tolerance of the mechanism's operation and prevents the rake teeth 122 from rigidly colliding with the cantilever screen bars 21 and damaging the equipment. The side of the rake teeth 122 facing the discharge direction is set as a wedge-shaped pushing surface. When the rake teeth 122 swing forward along an elliptical trajectory, the wedge-shaped surface cleaves into the interior of the adhered material clumps like an axe. The wedge-shaped pushing surface transforms the pushing into splitting, breaking the internal cohesion of the asphalt clumps, making them easier to disintegrate and discharge, while the streamlined surface reduces asphalt adhesion.

[0040] like Figures 4 to 9 and Figure 11 As shown: The unblocking mechanism 12 further includes a scraper plate 124 fixedly connected below the retraction path of the rake teeth 122 along the elliptical trajectory. The scraper plate 124 has a scraper groove 1241 that matches the rake teeth 122. It is configured to scrape off the adhering material on the surface of the rake teeth 122 by using the edge of the scraper groove 1241 when the rake teeth 122 retracts along the elliptical trajectory and passes through the scraper groove 1241.

[0041] Although air outlet 13 is provided for air cooling, fine asphalt sludge inevitably adheres to the surface of the rake teeth 122 during long-term operation. If not cleaned in time, the sludge will accumulate and thicken, causing the rake teeth 122 to coarsen and eventually jam in the limiting groove 112. A scraper plate 124 is fixedly connected below the retraction path of the rake teeth 122, with a scraping groove 1241 that fits tightly against the cross-section of the rake teeth 122. Using the elliptical trajectory of the drive assembly 121 driving the rake teeth 122, when the rake teeth 122 retract downwards, they are forced to pass through the scraping groove 1241. The edge of the scraping groove 1241 forcibly scrapes off the deposits on the surface of the rake teeth 122. Without manual intervention, the machine's own motion cycle achieves real-time cleaning of the rake teeth 122, keeping the surface of the rake teeth 122 smooth and preventing mechanical jamming due to deposit accumulation.

[0042] like Figures 4 to 8 and Figure 11 As shown: A waste collection hopper 125 is provided below the scraper 124; the scraper 124 is arranged at an inclination, and its lower end extends above the waste collection hopper 125, configured to guide the scraped-off adhering material into the waste collection hopper 125.

[0043] The material scraped off by the scraper 124 is typically highly viscous asphalt sludge. If left to fall freely, it would contaminate the transmission components below or mix into the finished product. By arranging the scraper 124 at an angle, it also functions as a sliding plate. Its lower end extends directly above the waste collection hopper 125. The scraped sludge slides down the slope under gravity and directly enters the waste hopper. This allows for the centralized diversion and collection of highly viscous and polluting sludge waste, maintaining the cleanliness of the internal environment of the screen box 1 and preventing secondary pollution inside the equipment.

[0044] like Figures 4 to 8 and Figure 11 As shown: A second screening component 22 is provided directly below the first screening component 2 for receiving and screening the undersize material passing through the gap of the cantilever screen bar 21; a fine material collection hopper 221 is provided below the second screening component 22, and a partition 222 is provided between the fine material collection hopper 221 and the waste material collection hopper 125.

[0045] The asphalt recycling process has strict requirements for gradation and must ensure the purity of the finished product. A second screening component 22 is installed directly below the first screening component 2 to receive material passing through the cantilever gap for secondary fine screening. Crucially, a vertical partition 222 is installed between the fine material collection hopper 221 below the second screening component 22 and the waste material collection hopper 125 below the unblocking mechanism 12. This partition 222 completely isolates the screening and material discharge area from the unblocking and waste discharge area. The partition 222 physically prevents the contaminated material (large agglomerates, scraped sludge) discharged from the unblocking mechanism 12 from mixing into the clean material (finely screened finished aggregate), ensuring the accuracy of the gradation and the quality of the raw materials in the recycled asphalt mixture.

[0046] like Figure 1 , Figure 3 , Figure 8 and Figure 9 As shown: the cantilever screen bar 21 is made of wear-resistant steel bar with a rectangular or trapezoidal cross section; the clearance between the free end of the cantilever screen bar 21 and the limiting groove 112 is less than the minimum effective screening particle size of the asphalt milling material.

[0047] Circular cross-section screen bars are prone to asphalt coating and rotational sliding along the circumference, leading to jamming. This is addressed by using wear-resistant steel bars with rectangular or trapezoidal cross-sections. The trapezoidal cross-section (wider at the top and narrower at the bottom) forms an inverted funnel-shaped screen opening. Once material passes through the upper surface, the space below increases, making it easy for the material to fall off due to gravity. The clearance is set to be less than the minimum effective particle size, ensuring that only materials smaller than this size can pass through, while materials larger than this size are forced to remain on the screen surface and processed by the rake teeth 122. The sharp edges formed by the trapezoidal or rectangular cross-section have a shearing effect, cutting off some of the adhering material; while the lower-widening, upper-narrowing clearance utilizes gravity to prevent particles from wedging and jamming deep within the screen openings.

[0048] like Figures 1 to 4 and Figure 11 As shown: There are two air outlets 13, which are located at both ends of the width direction of the limiting plate 111.

[0049] To cover the unblocking area of ​​the wide screen surface and avoid cooling dead zones, this embodiment provides air outlets 13 at both ends of the limiting plate 111 in the width direction. Airflow is sprayed from both sides or across the entire width, covering all the mating gaps between the rake teeth 122 and the limiting grooves 112. This ensures that each rake tooth 122 and each limiting groove 112 receives sufficient cooling, eliminating local hot spots and preventing asphalt melting and adhesion due to excessively high local temperatures.

[0050] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A multi-stage anti-clogging vibrating screen for asphalt pavement milling material, comprising a screen box (1) for driving the material to move along the screening direction, characterized in that, The top of the screen box (1) is provided with a first screening component (2), which includes a plurality of cantilever screen bars (21) arranged inclined along the flow direction of the material. The cantilever screen bars (21) have a fixed end that is fixedly connected to the screen box (1) and a free end that extends along the flow direction of the material. The screen box (1) is provided with a limiting component (11) at the free end of the cantilever screen bar (21). The limiting component (11) includes a limiting plate (111) with multiple limiting grooves (112). The free end of the cantilever screen bar (21) is inserted into the limiting groove (112) to limit the lateral swing of the cantilever screen bar (21). A clearing mechanism (12) is provided on the side of the limiting component (11). The clearing mechanism (12) includes a driving component (121) and rake teeth (122). The rake teeth (122) are configured to reciprocate under the drive of the driving component (121) so as to intermittently insert into the gap between the cantilever screen bar (21) and the limiting groove (112). The unblocking mechanism (12) is provided with an air outlet (13) on its side, and the air outlet (13) is configured to spray airflow toward the area where the rake teeth (122) and the limiting groove (112) cooperate.

2. The multi-stage anti-clogging vibrating screen for asphalt pavement milling material according to claim 1, characterized in that, The drive assembly (121) includes a rotating shaft (1211), an eccentric wheel (1212), and a connecting rod (1213). The rotating shaft (1211) is rotatably disposed inside the screen box (1). The eccentric wheel (1212) is sleeved on the rotating shaft (1211). The bottom end of the connecting rod (1213) is sleeved on the eccentric wheel (1212) through a bearing. The top end of the connecting rod (1213) extends to the limiting assembly (11) and is connected to the rake teeth (122). When the eccentric wheel (1212) rotates, the connecting rod (1213) drives the rake teeth (122) to reciprocate.

3. A multi-stage anti-clogging vibrating screen for asphalt pavement milling material according to claim 2, characterized in that, The connecting rod (1213) has a waist-shaped guide groove (12131) in the middle, and the side wall of the screen box (1) is provided with a positioning pin (12132) that passes through the guide groove (12131); the configuration is to limit the movement of the connecting rod (1213) by using the positioning pin (12132), so that the rake teeth (122) move along an elliptical trajectory, the elliptical trajectory including a lifting section that inserts into the gap and a pushing section that swings in the discharge direction.

4. A multi-stage anti-clogging vibrating screen for asphalt pavement milling material according to claim 2, characterized in that, The unblocking mechanism (12) also includes a mounting frame (123), which is connected to the top of the connecting rod (1213); there are multiple rake teeth (122), and the multiple rake teeth (122) are spaced apart and independently installed on the mounting frame (123), and the position of the rake teeth (122) corresponds one-to-one with the position of the limiting groove (112).

5. A multi-stage anti-clogging vibrating screen for asphalt pavement milling material according to claim 1, characterized in that, The top of the rake tooth (122) is conical and is used to guide the free end gap of the inserted cantilever screen bar (21); the rake tooth (122) is provided with a wedge-shaped pushing surface on the side facing the material outflow direction, which is configured to use the wedge-shaped pushing surface to generate splitting and pushing action on the material in the gap.

6. A multi-stage anti-clogging vibrating screen for asphalt pavement milling material according to claim 3, characterized in that, The The unblocking mechanism (12) also includes a scraper plate (124) fixedly connected below the retraction path of the rake teeth (122) along the elliptical trajectory. The scraper plate (124) has a scraper groove (1241) that matches the rake teeth (122). It is configured to scrape off the adhering material on the surface of the rake teeth (122) by using the edge of the scraper groove (1241) when the rake teeth (122) retract along the elliptical trajectory and pass through the scraper groove (1241).

7. A multi-stage anti-clogging vibrating screen for asphalt pavement milling material according to claim 6, characterized in that, A waste collection hopper (125) is provided below the scraper (124); the scraper (124) is arranged at an angle, and its lower end extends above the waste collection hopper (125), configured to guide the scraped-off adhering material into the waste collection hopper (125).

8. A multi-stage anti-clogging vibrating screen for asphalt pavement milling material according to claim 7, characterized in that, A second screening component (22) is provided directly below the first screening component (2) for receiving and screening the undersize material passing through the gap of the cantilever screen bar (21); a fine material collection hopper (221) is provided below the second screening component (22), and a partition (222) is provided between the fine material collection hopper (221) and the waste material collection hopper (125).

9. A multi-stage anti-clogging vibrating screen for asphalt pavement milling material according to any one of claims 1-8, characterized in that, The cantilever screen bar (21) is made of wear-resistant steel bar with a rectangular or trapezoidal cross section; the clearance between the free end of the cantilever screen bar (21) and the limiting groove (112) is less than the minimum effective screening particle size of the asphalt milling material.

10. A multi-stage anti-clogging vibrating screen for asphalt pavement milling material according to any one of claims 1-8, characterized in that, The air outlet (13) has two outlets, which are located at the two ends of the width direction of the limiting plate (111).

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