A screening device for construction sand and gravel

Abstract

The application discloses a kind of screening devices of building sandstone, it is related to sandstone screening technical field, including screening frame, screening frame from high to low sequentially set first soil and stone screening mechanism and second stone screening mechanism, first soil and stone screening mechanism includes concentric roller and eccentric roller, is rotatably installed with several concentric rollers along the inclined direction of screening frame, eccentric roller is rotatably installed between adjacent two concentric rollers, and extrusion screening gap is formed between eccentric roller and concentric roller, second stone screening mechanism includes longitudinal screening plate and transverse screening beam, is arranged with several longitudinal screening plates along the width direction spacing of screening frame, is arranged with several transverse screening beams along the length direction spacing of screening frame, and transverse screening beam and longitudinal screening plate are staggered to form screening net, after first screening pretreatment, the purity of final screening under small diameter stone block is significantly improved, impurity content is greatly reduced, and plate type screening net structure has the advantages of larger bearing area, higher structural strength, prolongs the service life of equipment.

Description

Technical Field

[0001] This invention relates to the field of sand and gravel screening technology, specifically to a screening device for construction sand and gravel. Background Technology

[0002] In fields such as construction engineering, road paving, and concrete preparation, sand and gravel are core components of basic building materials, and their quality directly affects the stability and durability of engineering structures. Among them, small-diameter stones with smaller particle sizes are widely used in subbase paving and small component casting due to their good gradation and filling properties. High purity is required for these stones, and the mixing of impurities such as soil and fine sand must be minimized to ensure the quality of subsequent construction.

[0003] However, naturally mined or artificially collected sand and gravel raw materials often contain a large amount of soil clods, fine sand, and stones of different sizes, resulting in a complex composition and uneven particle size distribution. Current sand and gravel screening operations in the industry generally suffer from insufficient targeting: existing equipment designs are mostly focused on separating stones of different sizes, without specifically addressing the efficient screening of soil and fine sand embedded within the sand and gravel. During screening, soil clods easily adhere to fine sand and small-diameter stones, making it difficult for existing screening methods to effectively separate them. This results in small-diameter stones still containing a large amount of fine sand and soil. The presence of these impurities severely affects the performance of small-diameter stones: for example, in concrete mix design, excessive soil and sand reduce the bonding strength between aggregates and cementitious materials, leading to a decrease in the compressive and flexural strength of the concrete; in road subbase construction, impurities affect the compaction and smoothness of the subbase, potentially causing settlement and cracking over long-term use, significantly limiting the application scenarios and value of small-diameter stones.

[0004] On the other hand, the existing sand and gravel screening equipment has significant structural design flaws, making it difficult to balance screening efficiency with equipment lifespan. Currently, most mainstream screening methods rely on a single screening mesh structure for particle grading. However, sand and gravel raw materials not only contain a large number of large, hard stones, but are also often fed directly into the screen. When sand and gravel fall from a height onto the screen surface, they generate strong impact loads. Because the screening mesh itself has a mesh structure with low structural strength, it is prone to wire breakage and frame deformation after long-term impact from large stones, significantly shortening equipment lifespan and increasing maintenance costs. Simultaneously, fine sand and soil clods in the sand and gravel easily adhere to the mesh openings during screening, and some damp impurities can clump together, causing frequent screen blockages. Existing screening meshes are mostly fixed structures, lacking effective unblocking mechanisms. Blockages require manual cleaning after machine shutdown, which is not only cumbersome but also severely interrupts the screening process, leading to a significant reduction in screening efficiency and making it difficult to meet the continuous operation requirements of large-scale construction scenarios.

[0005] In summary, existing sand and gravel screening technologies have significant shortcomings in terms of the specificity of impurity separation, equipment structural stability, and clogging handling capabilities. There is an urgent need for a screening device that can efficiently separate soil and sand from stones, is highly impact-resistant, and is not prone to clogging, in order to solve the current pain points in the industry and improve the quality and efficiency of sand and gravel screening. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a screening device for building sand and gravel to solve the deficiencies of the prior art.

[0007] The objective of this invention is achieved through the following technical solution: a screening device for building sand and gravel, comprising a screening frame, wherein a primary soil and stone screening mechanism and a secondary stone screening mechanism are sequentially arranged from high to low on the screening frame. The primary soil and stone screening mechanism includes concentric rollers and eccentric rollers. A plurality of concentric rollers are rotatably installed along the inclined direction of the screening frame, and an eccentric roller is rotatably installed between two adjacent concentric rollers. A squeezing screening gap is formed between the eccentric rollers and the concentric rollers, and the size of the squeezing screening gap changes with the rotation of the eccentric rollers. The secondary stone screening mechanism includes longitudinal screening plates and transverse screening beams. A plurality of longitudinal screening plates are spaced apart along the width direction of the screening frame, and a plurality of transverse screening beams are spaced apart along the length direction of the screening frame. The transverse screening beams and longitudinal screening plates are interlaced to form a screening mesh.

[0008] Furthermore, the rotational speed of the eccentric roller is greater than that of the concentric roller, and both ends of the eccentric roller are eccentrically fixed with eccentric shafts, while both ends of the concentric roller are coaxially fixed with screening shafts. The screening shafts and the eccentric shafts are rotatably connected to the screening frame.

[0009] Furthermore, a power box is installed on the screening frame, and a motor is installed inside the power box. A drive shaft and a driven shaft are rotatably arranged inside the power box. A drive sprocket and a driven sprocket are respectively mounted on the drive shaft and the driven shaft. The drive sprocket is connected to the driven sprocket via chain drive. The output shaft of the motor is connected to the drive shaft via a coupling. The screening shaft, located on the same side as the power box, passes through the power box and is connected to a first sprocket. An eccentric shaft, located on the same side as the power box, is equipped with a speed-increasing shaft. The speed-increasing shaft is rotatably connected to the screening frame. A second sprocket and a large gear are mounted on the speed-increasing shaft. Both the first sprocket and the second sprocket are driven and connected to a chain. The large gear meshes with an intermediate gear, and the intermediate gear meshes with a small gear. The small gear is mounted on the eccentric shaft. The number of teeth of the large gear, the intermediate gear, and the small gear gradually decreases.

[0010] Furthermore, the screening frame includes a left frame plate, a right frame plate, and mounting beams. Multiple mounting beams are spaced apart along the sand and gravel movement screening direction. Both ends of the mounting beams are connected to the left and right frame plates respectively by bolts. The primary soil and rock screening mechanism and the secondary stone screening mechanism are both located between the left and right frame plates. A central screening plate is fixed to the top of the mounting beams. Multiple longitudinal screening plates are arranged at equal intervals on both sides of the central screening plate. A guide shaft is provided below the mounting beams. Several first unblocking springs are fitted on the guide shafts. The longitudinal screening plates have slots for the mounting beams to pass through and circular holes for the guide shafts to pass through. A longitudinal screening plate is fitted between two adjacent first unblocking springs.

[0011] Furthermore, a linear groove is formed at the bottom of the mounting beam along its own length direction. The linear groove passes through one end of the mounting beam. The guide shaft is located in the linear groove and is fixedly connected to the mounting beam. The longitudinal screening plate forms a guide plate in the groove. The guide plate is slidably adapted to the linear groove. The circular hole is formed on the guide plate.

[0012] Furthermore, a longitudinal locking mechanism is provided below each of the mounting beams. The longitudinal locking mechanism includes a cam and a locking shaft. Both ends of the cam are fixed with locking shafts. The locking shafts at both ends of the cam are rotatably connected to the left frame plate and the right frame plate, respectively. A vertical groove is provided through the longitudinal screening plate. The cam passes through the vertical grooves of all the longitudinal screening plates at the same time. The downward pressure of the cam makes the longitudinal screening plate press against the mounting beam.

[0013] Furthermore, a sliding block is fixed at the bottom of the transverse screening beam, and a clearing groove is provided at the top of the middle screening plate corresponding to the position of the sliding block. The sliding block is slidably adapted to the clearing groove, and two sets of second clearing springs are provided in the clearing groove. The sliding block is arranged between the two sets of second clearing springs. The width of the transverse screening beam meets the requirement of always blocking the clearing groove, and the bottom surface of the transverse screening beam contacts the top surface of the longitudinal screening plate.

[0014] Furthermore, the central screening plate has a positioning hole extending through it along the length of the screening frame. The positioning hole passes through the unblocking groove, and a positioning shaft is installed inside the positioning hole. The embedded slider has a positioning hole through which the positioning shaft passes. The second unblocking spring is fitted onto the positioning shaft. Both ends of the central screening plate are connected to sealing plates by screws. The sealing plates are used to block the positioning holes.

[0015] Furthermore, the screening frame is provided with two sets of transverse locking mechanisms, and the transverse screening beam is located between the two sets of transverse locking mechanisms. The transverse locking mechanism includes a locking plate, which has the freedom to move along the width direction of the screening frame. The locking plate has a transverse locking groove on its end face near the transverse screening beam, and both ends of the transverse screening beam are respectively adapted to the transverse locking grooves of the two locking plates.

[0016] Furthermore, the screening frame is mounted on a screening base, and a vibrator is installed on the screening base to cause the screening frame to vibrate. A sand and gravel feed hopper is installed above the high end of the screening frame.

[0017] The beneficial effects of this invention are:

[0018] 1. The targeted separation of soil and sand from stones is achieved by using the combination of concentric and eccentric rollers. When the eccentric roller rotates, the extrusion and screening gap between it and the concentric roller changes periodically. On the one hand, it forms a squeezing and kneading effect on the sand and gravel raw materials, effectively separating the soil and fine sand adhering to the surface of the stones. On the other hand, the rotation speed of the eccentric roller is greater than that of the concentric roller, and the speed difference further enhances the screening effect, allowing soil and sand impurities to pass through the gap quickly and be screened down. It can also push the stones upward and prevent them from being stuck in the screening gap. After the primary screening pretreatment, the material processed by the secondary stone screening mechanism has significantly reduced soil and sand impurities. The purity of the small-diameter stones that are finally screened down is significantly improved, and the impurity content is greatly reduced.

[0019] 2. The input sand and gravel first act on the primary soil and rock screening mechanism. The concentric rollers and eccentric rollers form a rigid support structure, which first bears the impact load of the input feeding. Large stones are buffered by the roller surface and enter the secondary screening smoothly, reducing the impact intensity. At the same time, the longitudinal screening plate and the transverse screening beam of the plate structure form a screening mesh. Compared with the traditional grid screening mesh, the plate beam structure has a larger bearing area and higher structural strength, which can effectively resist the impact of large stones, reduce the failure of mesh breakage, frame deformation and other failures, significantly extend the service life of the equipment and reduce the later maintenance and replacement costs.

[0020] 3. During vibration, the movement freedom of the longitudinal screening plate and the transverse screening beam is restricted, ensuring that the aperture size of the screen mesh remains unchanged during the screening process, thus guaranteeing screening accuracy. When blockage occurs, a clearing operation is performed to unlock the movement freedom of the longitudinal screening plate and the transverse screening beam, allowing the blocked mesh to be cleared quickly and effectively by increasing the movement of the longitudinal screening plate and the transverse screening beam. This significantly improves screening efficiency and meets the operational needs of large-scale construction scenarios. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of a screening device for building sand and gravel according to the present invention. Figure 1 ;

[0022] Figure 2 This is a schematic diagram of the structure of a screening device for building sand and gravel according to the present invention. Figure 2 ;

[0023] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0024] Figure 4 This is a top view of a screening device for building sand and gravel according to the present invention;

[0025] Figure 5 for Figure 4 Sectional view along line AA;

[0026] Figure 6 for Figure 5 Enlarged view at point B in the middle;

[0027] Figure 7 This is a schematic diagram showing the cooperation between the transverse screening beam and the middle screening plate in a screening device for building sand and gravel according to the present invention.

[0028] Figure 8 for Figure 7 Enlarged view at point C;

[0029] Figure 9 This is a schematic diagram of the structure of a screening device for building sand and gravel according to the present invention. Figure 3 ;

[0030] Figure 10 for Figure 9 Enlarged view at point D;

[0031] In the diagram, 1-screening frame, 2-concentric roller, 3-eccentric roller, 4-longitudinal screening plate, 5-transverse screening beam, 6-eccentric shaft, 7-screening shaft, 8-power box, 9-drive shaft, 10-driven shaft, 11-drive sprocket, 12-driven sprocket, 13-first sprocket, 14-speed-increasing shaft, 15-second sprocket, 16-large gear, 17-small gear, 18-left frame plate, 19-right frame plate, 20-mounting beam, 21-linear groove, 22-guide shaft, 23-first unblocking spring, 24-groove opening, 25-round hole, 26-guide Plate, 27-Cam, 28-Locking shaft, 29-Vertical groove, 30-Embedded slider, 31-Unblocking groove, 32-Second unblocking spring, 33-Positioning hole, 34-Positioning shaft, 35-Positioning round hole, 36-Sealing plate, 37-Locking plate, 38-Horizontal locking groove, 39-Screening base, 40-Sand and gravel feed hopper, 41-Intermediate gear, 42-Telescopic rod, 43-Vibration spring, 44-Central screening plate, 45-Hydraulic cylinder, 46-Rack, 47-Linkage column, 48-Locking gear, 49-Linkage inclined groove, 50-Linkage shaft. Detailed Implementation

[0032] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0033] Example 1

[0034] like Figures 1 to 10As shown, a screening device for construction sand and gravel includes a screening frame 1. The screening frame 1 has a primary soil and stone screening mechanism and a secondary stone screening mechanism arranged sequentially from high to low. The primary soil and stone screening mechanism includes concentric rollers 2 and eccentric rollers 3. Several concentric rollers 2 are rotatably mounted along the inclined direction of the screening frame 1. An eccentric roller 3 is rotatably mounted between two adjacent concentric rollers 2. The rotational speed of the eccentric roller 3 is greater than the rotational speed of the concentric rollers 2. Eccentric shafts 6 are eccentrically fixed at both ends of the eccentric roller 3. Screening shafts 7 are coaxially fixed at both ends of the concentric rollers 2. The screening shafts 7 and eccentric shafts 6... The eccentric roller 3 and concentric roller 2 are rotatably connected to the screening frame 1. A squeezing gap is formed between them, and the size of the squeezing gap changes with the rotation of the eccentric roller 3. The secondary stone screening mechanism includes longitudinal screening plates 4 and transverse screening beams 5. Several longitudinal screening plates 4 are arranged at intervals along the width direction of the screening frame 1, and several transverse screening beams 5 are arranged at intervals along the length direction of the screening frame 1. The transverse screening beams 5 and the longitudinal screening plates 4 are interlaced to form a screening mesh. The screening frame 1 is mounted on the screening base 39, and a vibrator is mounted on the screening base 39. The vibrator is used for... The screening frame 1 vibrates. A sand and gravel feed hopper 40 is installed above the high end of the screening frame 1. Sand and gravel raw materials are fed into the sand and gravel feed hopper 40 by an excavator. The sand and gravel first fall onto the primary soil and rock screening mechanism. The rotation of the concentric roller 2 and the eccentric roller 3 transports the sand and gravel downwards. At the same time, the vibrator causes the screening frame 1 to vibrate up and down on the screening base 39, which strengthens the movement of the sand and gravel and prevents the sand and gravel from accumulating and affecting the screening effect. The rotation of the eccentric roller 3 causes the screening gap to change periodically. On the one hand, it can squeeze and crush the clumps of soil and prevent the screening gap from being blocked. On the other hand, it can squeeze and knead the soil layer on the sand and gravel, which has the effect of peeling off the soil and fine sand adhering to the surface of the stones. Secondly, the rotation speed of the eccentric roller 3 is greater than that of the concentric roller 2, forming a speed difference to further enhance the screening effect, so that soil and sand impurities can be quickly screened through the screening gap. It can also push the stones upward to move upward, avoiding the stones from being stuck in the screening gap. After the primary screening pretreatment, the material processed by the secondary stone screening mechanism has significantly reduced soil and sand impurities, and the purity of the small-diameter stones that are finally screened out is significantly improved, and the impurity content is greatly reduced.This ensures the performance of small-diameter stones in concrete preparation and road subbase paving, avoiding problems such as insufficient structural strength and poor compaction caused by impurities, thus expanding the application scenarios and value of small-diameter stones. Stones entering the secondary stone screening mechanism are screened by size through a screening mesh formed by the longitudinal screening plate 4 and the transverse screening beam 5. Because the sand and gravel are buffered by the primary soil and stone screening mechanism, the impact force of the stones is significantly reduced, lowering the impact force when the stones enter the secondary stone screening mechanism and reducing the burden on the secondary stone screening mechanism. Furthermore, the longitudinal screening plate 4 and the transverse screening beam 5 are plate structures. Compared to traditional mesh screening meshes, the plate-beam structure has a larger load-bearing area and higher structural strength, effectively resisting the impact of large-particle stones, reducing mesh breakage, frame deformation, and other failures, significantly extending the service life of the equipment and reducing subsequent maintenance and replacement costs. In specific implementation, the screening frame 1 is installed on the screening base 39 through a spring damping component. The spring damping component includes a vertically arranged telescopic rod 42 and a vibration spring 43 fitted on the telescopic rod 42. The two ends of the telescopic rod 42 are respectively connected to the screening frame 1 and the screening base 39, so that the vibrator can smoothly make the screening frame 1 vibrate up and down. This is the prior art and will not be described in detail.

[0035] Example 2

[0036] Based on Example 1, such as Figures 1 to 6As shown, a power box 8 is installed on the screening frame 1. A motor is installed inside the power box 8. A drive shaft 9 and a driven shaft 10 are rotatably mounted inside the power box 8. A drive sprocket 11 and a driven sprocket 12 are respectively mounted on the drive shaft 9 and driven shaft 10. The drive sprocket 11 is connected to the driven sprocket 12 via a chain drive. The output shaft of the motor is connected to the drive shaft 9 via a coupling. A screening shaft 7, located on the same side as the power box 8, passes through the power box 8 and is connected to a first sprocket 13. An offset sprocket 7, also located on the same side as the power box 8, is... The spindle 6 is equipped with a speed-increasing shaft 14, which is rotatably connected to the screening frame 1. A second sprocket 15 and a large gear 16 are mounted on the speed-increasing shaft 14. Both the first sprocket 13 and the second sprocket 15 are connected to a chain. The large gear 16 meshes with an intermediate gear 41, which in turn meshes with a small gear 17. The small gear 17 is mounted on the eccentric shaft 6. The number of teeth on the large gear 16, intermediate gear 41, and small gear 17 gradually decreases. The motor drives the drive shaft 9 to rotate, which in turn drives the drive sprocket. The drive sprocket 11 rotates, driving the driven sprocket 12 to rotate via a chain. The rotation of the chain drives the first sprocket 13 and the second sprocket 15 to rotate. The first sprocket 13 drives the concentric roller 2 to rotate via the screening shaft 7. The second sprocket 15 drives the speed-increasing shaft 14 to rotate. The speed-increasing shaft 14 drives the large gear 16 to rotate. The large gear 16 drives the small gear 17 to rotate via the intermediate gear 41. The small gear 17 drives the eccentric shaft 6 to rotate. The eccentric shaft 6 drives the eccentric roller 3 to rotate, thus driving a series of rotations. The source synchronously drives the eccentric roller 3 and the concentric roller 2 to rotate, resulting in a compact structure and high synchronization. Secondly, the number of teeth of the large gear 16, the intermediate gear 41 and the small gear 17 gradually decreases, which can increase the rotational speed of the eccentric roller 3, so that the eccentric roller 3 and the concentric roller 2 form a differential conveying, allowing the eccentric roller 3 to have a higher rotational speed to complete the plucking of stones and avoid the stones from being stuck in the screening gap. The setting of the intermediate gear 41 makes the eccentric roller 3 and the concentric roller 2 rotate in the same direction, which can smoothly convey the stones.

[0037] Example 3

[0038] Based on Example 2, such as Figures 1 to 3As shown, the screening frame 1 includes a left frame plate 18, a right frame plate 19, and mounting beams 20. Multiple mounting beams 20 are spaced apart along the sand and gravel movement screening direction. Both ends of each mounting beam 20 are bolted to the left frame plate 18 and the right frame plate 19 respectively. The primary soil and rock screening mechanism and the secondary stone screening mechanism are located between the left frame plate 18 and the right frame plate 19. A central screening plate 44 is fixed to the top of each mounting beam 20. Multiple longitudinal screening plates 4 are equally spaced on both sides of the central screening plate 44. A guide shaft 22 is located below each mounting beam 20. A number of first unblocking springs 23 are fitted onto the guide shaft 22. A slot 24 is provided on the longitudinal screening plate 4 for the installation beam 20 to pass through. A circular hole 25 is provided on the longitudinal screening plate 4 for the guide shaft 22 to pass through. A longitudinal screening plate 4 is fitted between two adjacent first unblocking springs 23. A linear groove 21 is provided at the bottom of the installation beam 20 along its length. The linear groove 21 passes through one end of the installation beam 20. The guide shaft 22 is located within the linear groove 21 and is fixedly connected to the installation beam 20. The longitudinal screening plate 4 forms a guide shaft within the slot 24. The guide plate 26 slides and adapts to the linear groove 21. Circular holes 25 are formed on the guide plate 26. The longitudinal screening plates 4 are installed from both ends of the mounting beam 20. First, a first unblocking spring 23 is mounted on the guide shaft 22, then a longitudinal screening plate 4 is mounted, followed by another first unblocking spring 23. This process is repeated to complete the installation of multiple longitudinal screening plates 4. After the longitudinal screening plates 4 are installed, the last first unblocking spring 23 is mounted, so that the two outermost first unblocking springs 23 contact the left frame plate 18 and... The right frame plate 19 allows multiple longitudinal screening plates 4 to be slidably mounted on the mounting beam 20 via multiple first unblocking springs 23. The mounting beam 20 guides the movement of the longitudinal screening plates 4, and the movement of the longitudinal screening plates 4 adjusts the gap between adjacent longitudinal screening plates 4. By increasing the distance between the longitudinal screening plates 4, stones stuck between two longitudinal screening plates 4 can be discharged, achieving rapid unblocking. The unblocking operation can be completed without disassembling the longitudinal screening plates 4 and the transverse screening beam 5, making the operation simple and quick. Furthermore, the guide shaft 22 and the first unblocking springs 23 are protected within the linear groove 21, preventing the screened stones from affecting the first unblocking springs 23 and extending their service life.

[0039] Example 4

[0040] Based on Example 3, such as Figures 1 to 5As shown, each mounting beam 20 is equipped with a longitudinal locking mechanism below it. The longitudinal locking mechanism includes a cam 27 and a locking shaft 28. Both ends of the cam 27 are fixed with locking shafts 28. The locking shafts 28 at both ends of the cam 27 are rotatably connected to the left frame plate 18 and the right frame plate 19, respectively. Vertical slots 29 are opened through the longitudinal screening plates 4. The cam 27 passes through all the vertical slots 29 of the longitudinal screening plates 4. By pressing down on the cam 27, the longitudinal screening plates 4 are pressed against the mounting beam 20. The cam 27 can unlock and lock the degree of freedom of movement of the longitudinal screening plates 4, realizing the switching between screening and unblocking operations. Specifically, during screening, the distal end of the cam 27... The downward deflection causes cam 27 to simultaneously press down all the longitudinal screening plates 4, pressing them against the mounting beam 20. This ensures that the position of the longitudinal screening plates 4 does not change during vibrating screening, thus maintaining the screen mesh aperture size and improving the screening accuracy of stones, enabling precise differentiation of stones of different sizes. When clearing blockages, cam 27 rotates in the opposite direction, separating the distal end of cam 27 from the longitudinal screening plates 4, unlocking the sliding freedom of the longitudinal screening plates 4 on the mounting beam 20. At this time, by increasing the distance between the longitudinal screening plates 4 at the blockage point, the blocked stones fall down, achieving rapid clearing without disassembly.

[0041] Example 5

[0042] Based on Example 4, such as Figures 1 to 8As shown, a sliding block 30 is fixed to the bottom of the transverse screening beam 5. A clearing groove 31 is provided on the top of the middle screening plate 44 corresponding to the position of the sliding block 30. The sliding block 30 slides within the clearing groove 31. Two sets of second clearing springs 32 are provided within the clearing groove 31. The sliding block 30 is arranged between the two sets of second clearing springs 32. The width of the transverse screening beam 5 meets the requirement of always blocking the clearing groove 31, and the bottom surface of the transverse screening beam 5 contacts the top surface of the longitudinal screening plate 4. The middle screening plate 44 extends along the length of the screening frame 1. A positioning hole 33 is provided through the unblocking groove 31. A positioning shaft 34 is installed inside the positioning hole 33. A positioning hole 35 is provided on the embedded slider 30 for the positioning shaft 34 to pass through. The second unblocking spring 32 is fitted onto the positioning shaft 34. Both ends of the middle screening plate 44 are connected to the sealing plate 36 by screws. The sealing plate 36 is used to block the positioning hole 33. After the longitudinal screening plate 4 is installed, the transverse screening beam 5 is installed. The second unblocking spring 32 is installed in the unblocking groove 31. Two second unblocking springs are installed in each unblocking groove 31. Spring 32, causing the two second unblocking springs 32 to abut against the side walls at both ends of the unblocking chute 31 respectively, creating a space between the two second unblocking springs 32 for assembling the mounting slider 30. The mounting slider 30 is installed between the two second unblocking springs 32 in the unblocking chute 31. Then, one of the sealing plates 36 is removed, and the positioning shaft 34 is inserted into the positioning hole 33 of the middle screening plate 44, so that the positioning shaft 34 passes through the positioning hole 35 of the mounting slider 30, thereby slidingly connecting the transverse screening beam 5 to the middle screening plate 44. At this time, the second unblocking springs... Spring 32 is sleeved on positioning shaft 34, so that transverse screening beam 5 will not detach from the middle screening plate 44 and can move along the axial direction of positioning shaft 34. Transverse screening beam 5 only contacts longitudinal screening plate 4 and does not directly connect to longitudinal screening plate 4, so that longitudinal screening plate 4 can slide on mounting beam 20. At the same time, transverse screening beam 5 can slide on middle screening plate 44. Transverse screening beam 5 and longitudinal screening plate 4 move at the same time, which can increase the transverse and longitudinal dimensions of the blocked mesh at the same time, so that the stones blocked in the mesh can fall down quickly to complete the unblocking.

[0043] Example 6

[0044] Based on Example 5, such as Figures 1 to 10As shown, the screening frame 1 is equipped with two sets of transverse locking mechanisms. The transverse screening beam 5 is located between the two sets of transverse locking mechanisms. The transverse locking mechanism includes a locking plate 37, which has the freedom to move along the width direction of the screening frame 1. The locking plate 37 has a transverse locking groove 38 on its end face near the transverse screening beam 5. Both ends of the transverse screening beam 5 are respectively fitted into the transverse locking grooves 38 of the two locking plates 37. During screening, the locking plate 37 moves close to the transverse screening beam 5, so that the ends of the transverse screening beam 5 are fitted into the transverse locking grooves 38. This prevents the transverse screening beam 5 from moving along the length of the longitudinal screening plate 4. Combined with the locking mechanism of the cam 27 on the longitudinal screening plate 4, the mesh size of the screening net formed by the longitudinal screening plate 4 and the transverse screening beam 5 is fixed, ensuring precise screening of stones of the required size. During unblocking, the distal end of the cam 27 separates from the longitudinal screening plate 4, and the locking plate 37 separates from the transverse screening beam 5. Simultaneously, the transverse movement freedom of the longitudinal screening plate 4 and the longitudinal movement freedom of the transverse screening beam 5 are unlocked. At this point, no more sand or gravel is added, and the vibrator... The vibrating screen frame 1 causes the clogged stones to move downwards, which in turn moves the longitudinal screening plate 4, deforming the first unblocking spring 23. The transverse screening beam 5 moves, deforming the second unblocking spring 32. This increases the mesh size at the blockage, allowing the stones to fall smoothly and achieving rapid unblocking. After a period of unblocking, the vibrator is turned off, and the unblocking status of the secondary stone screening mechanism is checked. If the blockage is not completely cleared, workers use a jack to strike the clogged stones downwards. The blockage of stones is caused by the compression of the transverse screening beam 5 and the longitudinal screening plate 4, which move to complete the unblocking process. After the unblocking is complete, the longitudinal screening plate 4 is reset under the action of the first unblocking spring 23, and the transverse screening beam 5 is reset under the action of the second unblocking spring 32. Then, the cam 27 reverses and resets, pressing the longitudinal screening plate 4 onto the mounting beam 20. The end face of the transverse screening beam 5 is fitted into the transverse locking groove 38, thereby restricting the degree of freedom of movement of the transverse screening beam 5 and the longitudinal screening plate 4, fixing the aperture of the screening mesh, and achieving precise screening. In specific implementation, when it is necessary to screen stones of different volume ranges, multiple sets of secondary stone screening mechanisms are set up. Multiple sets of secondary stone screening mechanisms are connected in sequence along the screening direction of the stones. The mesh size formed by the secondary stone screening mechanisms from top to bottom gradually increases, thereby obtaining stones of different volume ranges.

[0045] Example 7

[0046] Based on Example 6, such as Figures 1 to 10As shown, each set of transverse locking mechanisms is equipped with a linkage drive mechanism, which includes a hydraulic cylinder 45, a rack 46, and a linkage column 47. The cylinder body of the hydraulic cylinder 45 is mounted on the screening frame 1. The telescopic shaft of the hydraulic cylinder 45 is connected to the locking plate 37. A locking gear 48 is mounted on the locking shaft 28. Multiple locking gears 48 on the same side simultaneously mesh with the rack 46. The rack 46 is slidably mounted on the screening frame 1. The linkage column 47 is fixed to the bottom of the locking plate 37. A linkage groove 49 is opened on the bottom surface of the linkage column 47. A linkage shaft 50 is fixed to the top of the rack 46. The top of the linkage shaft 50 moves into the linkage groove 49. When locking the longitudinal screening plate 4 and the transverse screening beam 5, the hydraulic cylinder 45 drives the locking plate 37 to move closer to the transverse screening beam 5. At the same time, the locking plate 37 drives the linkage column 47 to move. Under the action of the linkage groove 49, the linkage shaft 50 drives the rack 46 to move. The rack 46 simultaneously drives the linkage column 47. Some locking gears 48 deflect, causing locking shaft 28 to drive cam 27 to press the longitudinal screening plate 4 downwards. When the end face of transverse screening beam 5 is fitted into transverse locking groove 38, the longitudinal screening plate 4 is pressed against mounting beam 20. Thus, locking the longitudinal screening plate 4 and transverse screening beam 5 is completed simultaneously by a single power source. When the movement freedom of transverse screening beam 5 and longitudinal screening plate 4 is unlocked, hydraulic cylinder 45 drives locking plate 37 to move away from transverse screening beam 5. Locking plate 37 simultaneously drives linkage column 47 to move in the opposite direction, causing linkage shaft 50 to drive rack 46 to move in the opposite direction. Rack 46 drives locking gear 48 to deflect in the opposite direction, thereby causing cam 27 to deflect in the opposite direction, separating the distal end of cam 27 from longitudinal screening plate 4. At the same time, transverse screening beam 5 disengages from transverse locking groove 38, completing the unlocking action of transverse screening beam 5 and longitudinal screening plate 4. The synchronization is high, and only one power source is needed, making the structure more compact.

Claims

1. A screening device for construction sand and gravel, comprising a screening frame, characterized in that, The screening frame is arranged with a primary soil and rock screening mechanism and a secondary stone screening mechanism from high to low. The primary soil and rock screening mechanism includes concentric rollers and eccentric rollers. Several concentric rollers are rotatably installed along the inclined direction of the screening frame. An eccentric roller is rotatably installed between two adjacent concentric rollers. The rotational speed of the eccentric roller is greater than that of the concentric roller. An eccentric shaft is eccentrically fixed at both ends of the eccentric roller. A screening shaft is coaxially fixed at both ends of the concentric roller. The screening shaft and the eccentric shaft are rotatably connected to the screening frame. A squeezing screening gap is formed between the eccentric roller and the concentric roller. The size of the squeezing screening gap changes with the rotation of the eccentric roller. The secondary stone screening mechanism includes longitudinal screening plates and transverse screening beams. Several longitudinal screening plates are arranged at intervals along the width direction of the screening frame, and several transverse screening beams are arranged at equal intervals along the length direction of the screening frame. The transverse screening beams and longitudinal screening plates are interlaced to form a screening mesh. The longitudinal screening plates and transverse screening beams are plate structures used to resist the impact of large stone particles. The secondary stone screening mechanism is set up in multiple groups, and the multiple groups of the secondary stone screening mechanism are connected together in sequence along the screening direction of the stone. The mesh size formed by the secondary stone screening mechanism from top to bottom gradually increases, thereby obtaining stones of different volume ranges.

2. The screening device for building sand and gravel according to claim 1, characterized in that, A power box is installed on the screening frame, and a motor is installed inside the power box. A drive shaft and a driven shaft are rotatably arranged inside the power box. A drive sprocket and a driven sprocket are respectively mounted on the drive shaft and the driven shaft. The drive sprocket is connected to the driven sprocket via chain drive. The output shaft of the motor is connected to the drive shaft via a coupling. The screening shaft, located on the same side as the power box, passes through the power box and is connected to a first sprocket. An eccentric shaft, also located on the same side as the power box, is equipped with a speed-increasing shaft. The speed-increasing shaft is rotatably connected to the screening frame. A second sprocket and a large gear are mounted on the speed-increasing shaft. Both the first sprocket and the second sprocket are driven by a chain. The large gear meshes with an intermediate gear, and the intermediate gear meshes with a small gear. The small gear is mounted on the eccentric shaft. The number of teeth of the large gear, intermediate gear, and small gear gradually decreases.

3. The screening device for building sand and gravel according to claim 1, characterized in that, The screening frame includes a left frame plate, a right frame plate, and mounting beams. Multiple mounting beams are spaced apart along the direction of sand and gravel movement and screening. Both ends of the mounting beams are connected to the left and right frame plates respectively by bolts. The primary soil and rock screening mechanism and the secondary stone screening mechanism are located between the left and right frame plates. A central screening plate is fixed to the top of the mounting beams. Multiple longitudinal screening plates are arranged at equal intervals on both sides of the central screening plate. A guide shaft is provided below the mounting beams. Several first unblocking springs are fitted on the guide shaft. The longitudinal screening plates have slots for the mounting beams to pass through and circular holes for the guide shaft to pass through. A longitudinal screening plate is fitted between two adjacent first unblocking springs.

4. The screening device for building sand and gravel according to claim 3, characterized in that, The bottom of the mounting beam has a linear groove along its length, the linear groove passes through one end of the mounting beam, the guide shaft is located in the linear groove and is fixedly connected to the mounting beam, the longitudinal screening plate forms a guide plate in the groove, the guide plate slides to fit the linear groove, and the circular hole is opened on the guide plate.

5. A screening device for building sand and gravel according to claim 4, characterized in that, Each of the mounting beams is provided with a longitudinal locking mechanism, which includes a cam and a locking shaft. Both ends of the cam are fixed with locking shafts, and the locking shafts at both ends of the cam are rotatably connected to the left frame plate and the right frame plate, respectively. Vertical slots are opened through the longitudinal screening plates, and the cam passes through the vertical slots of all the longitudinal screening plates at the same time. The downward pressure of the cam makes the longitudinal screening plates press against the mounting beam.

6. The screening device for building sand and gravel according to claim 3, characterized in that, The bottom of the transverse screening beam is fixed with an embedded slider. The top of the middle screening plate is provided with a clearing groove corresponding to the position of the embedded slider. The embedded slider is slidably adapted in the clearing groove. Two sets of second clearing springs are provided in the clearing groove. The embedded slider is arranged between the two sets of second clearing springs. The width of the transverse screening beam meets the requirement of always blocking the clearing groove, and the bottom surface of the transverse screening beam contacts the top surface of the longitudinal screening plate.

7. A screening device for building sand and gravel according to claim 6, characterized in that, The central screening plate has a positioning hole extending through it along the length of the screening frame. The positioning hole passes through the unblocking groove and a positioning shaft is installed inside the positioning hole. The embedded slider has a positioning hole for the positioning shaft to pass through. The second unblocking spring is fitted onto the positioning shaft. Both ends of the central screening plate are connected to sealing plates by screws. The sealing plates are used to block the positioning holes.

8. A screening device for building sand and gravel according to claim 7, characterized in that, The screening frame is equipped with two sets of transverse locking mechanisms. The transverse screening beam is located between the two sets of transverse locking mechanisms. The transverse locking mechanism includes a locking plate. The locking plate has the freedom to move along the width direction of the screening frame. The end face of the locking plate near the transverse screening beam is provided with a transverse locking groove. The two ends of the transverse screening beam are respectively adapted to the transverse locking grooves of the two locking plates.

9. A screening device for building sand and gravel according to claim 1, characterized in that, The screening frame is mounted on the screening base, and a vibrator is installed on the screening base to make the screening frame vibrate. A sand and gravel feed hopper is installed above the high end of the screening frame.

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