Gravel screening machine
By designing the anti-knock structure and material discharge structure of the sand and gravel screening machine, the problems of screen clogging and sand and gravel agglomeration were solved, and efficient sand and gravel screening operation was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- POWERCHINA HUADONG ENG CORP LTD
- Filing Date
- 2025-05-21
- Publication Date
- 2026-05-01
AI Technical Summary
Existing sand and gravel screening machines are prone to screen clogging, and in humid environments, sand and gravel clump together, affecting the screening effect.
A sand and gravel screening machine was designed, comprising a mounting bracket, a screening box, a vibrator, a conveyor belt, a knocking structure, and a discharge structure. The knocking structure removes blockages, and the drying device in the discharge structure processes wet sand and gravel.
It effectively removes screen blockage, reduces sand and gravel agglomeration, and improves screening efficiency and effectiveness.
Smart Images
Figure CN224181380U_ABST
Abstract
Description
A sand and gravel screening machine Technical Field
[0001] This utility model relates to a sand and gravel screening machine. It is applicable to the field of screening equipment technology. Background Technology
[0002] Water conservancy projects are a general term for various engineering constructions undertaken to control, utilize, and protect surface and underground water resources and the environment. Sand and gravel are essential raw materials; therefore, sand and gravel screening machines are needed to obtain sufficient sand and gravel for construction in water conservancy projects.
[0003] However, the existing equipment has not solved the problem that after the sand and gravel screening machine is used, stones will easily clog the screen, making it impossible to screen sand and gravel. At the same time, it is time-consuming and laborious to manually clear the blockage. When the sand and gravel are in a relatively humid environment, the sand and gravel will be too wet and will clump together on the screening machine during the screening process, thus affecting the screening effect. Summary of the Invention
[0004] The technical problem to be solved by this utility model is: to solve the above-mentioned technical problem, this utility model provides a sand and gravel screening machine.
[0005] The technical solution adopted in this utility model is: a sand and gravel screening machine, which has the following features:
[0006] Mounting bracket;
[0007] The screening box is installed on the mounting bracket. The screening box is arranged at an angle and is open from top to bottom. The screening box contains a screen arranged along the length of the screening box. A material discharge structure is installed at the upper end of the screening box, and a material discharge port is provided at the lower end of the screening box at the position corresponding to the screen.
[0008] The oscillator structure is installed between the screening box and the mounting bracket, which can drive the screening box to oscillate on the mounting bracket;
[0009] The conveyor belt structure is installed on the mounting bracket below the screening box and can transport the materials screened out from the screening box.
[0010] The counter-tapping structure is installed on the mounting bracket and positioned below the screen in the screening box. The counter-tapping structure can move upward and tap the screen inside the screening box.
[0011] Inside the screening box, a first screen and a second screen are arranged sequentially from top to bottom. The diameter of the first screen is larger than that of the second screen. At the lower end of the screening box, a first discharge port and a second discharge port are respectively provided at positions corresponding to the first screen and the second screen.
[0012] At least two connecting brackets are connected between the screening box and the mounting bracket along the length of the screening box. The connecting bracket has a first mounting plate mounted on the mounting bracket and a second mounting plate mounted on the screening box. A telescopic rod is connected between the first mounting plate and the second mounting plate, and a first spring is fitted on the telescopic rod between the first mounting plate and the second mounting plate.
[0013] The conveyor belt structure has a first rotating shaft and a second rotating shaft mounted on a mounting bracket, a conveyor belt installed between the first rotating shaft and the second rotating shaft, a first motor mounted on the mounting bracket, and the first rotating shaft connected to the output shaft of the first motor.
[0014] The material feeding structure has a mounting frame that can be installed on a screening box, a vertically connected material feeding box is installed on the mounting frame, and a third screen is installed inside the material feeding box.
[0015] A first mounting hole is provided on the side wall of the material box, a second motor is installed in the first mounting hole, a fan blade is installed on the output shaft of the second motor, and a filter screen is installed in the first mounting hole.
[0016] The oscillator structure has a mounting base that is mounted on a mounting bracket via a support frame, and a vibrator is mounted on the mounting base. The vibrator is connected to a screening box.
[0017] The mounting bracket has a slot, and the support frame is fitted into the slot of the mounting bracket.
[0018] The counter-knocking structure has an auxiliary plate and a movable plate, which are connected to the auxiliary plate by a third spring. A knocking block is installed on the upper surface of the movable plate. A first mounting rod and a second mounting rod are installed on the side walls of the auxiliary plate and the movable plate. A first sliding groove and a second sliding groove are formed on the side walls of the mounting bracket at positions corresponding to the first and second mounting rods, arranged along the length of the sieve box. The first and second mounting rods extend out of the mounting bracket through the first and second sliding grooves, respectively. A plurality of first limiting grooves that can cooperate with the first mounting rod are formed on the lower side wall of the first sliding groove along the length of the first sliding groove. A plurality of second limiting grooves that can cooperate with the second mounting rod are formed on the upper side wall of the second sliding groove along the length of the second sliding groove.
[0019] Both the first mounting rod and the second mounting rod are threaded, and the first mounting rod and the second mounting rod are respectively mounted on the auxiliary plate and the movable plate through threaded engagement.
[0020] The beneficial effects of this utility model are as follows: This utility model uses a reverse-knocking structure to arrange a movable plate and an auxiliary plate connected by a third spring on a mounting bracket below the screening box. The first and second mounting rods pass through the first and second sliding grooves and are then threaded onto the auxiliary plate and movable plate. The cooperation between the first and second mounting rods with the first and second sliding grooves moves the auxiliary plate and movable plate to their corresponding positions. The reverse-knocking structure is then installed on the mounting bracket through the cooperation between the first and second mounting rods with the first and second limiting grooves. By pressing down on the second mounting rod, the movable plate moves towards the auxiliary plate, compressing the third spring. After releasing the second mounting rod, the movable plate moves upward under the action of the third spring. The knocking block on the movable plate strikes the screen inside the screening box, dislodging stones from the blockage. This reduces the likelihood of stones clogging the screen after use, preventing the screen from performing sand and gravel screening.
[0021] This invention features a material feeding structure installed at the top of the screening box. The sand and gravel to be screened are placed inside the box, and a third screen buffers the incoming material. During this buffering process, a drying fan provides simple drying of the sand and gravel. The dried sand and gravel are then discharged onto the screen of the screening box. This reduces the risk of sand and gravel clumping on the screening machine due to excessive moisture, which can affect the screening effect. The invention achieves a simple drying process during the initial feeding of the sand and gravel, reducing surface dryness and clumping. Attached Figure Description
[0022] Figure 1 is a three-dimensional structural diagram of this utility model.
[0023] Figure 2 is a schematic diagram of the mounting bracket in this utility model.
[0024] Figure 3 is a schematic diagram of the reverse knocking structure in this utility model.
[0025] Figure 4 is a schematic diagram of the sieving box in this utility model.
[0026] Figure 5 is a schematic diagram of the material feeding structure in this utility model.
[0027] In the diagram: 1. Mounting bracket; 1-1. Slot; 1-2. First sliding groove; 1-3. First limiting groove; 1-4. Second sliding groove; 1-5. Second limiting groove; 2. Screening box; 2-1. First screen; 2-2. First discharge port; 2-3. Second screen; 2-4. Second discharge port; 3. Discharge structure; 3-1. Mounting frame; 3-2. Discharge box; 3-3. Third screen; 3-4. First mounting hole; 3-5. Second motor; 3-6. Fan blade; 3-7. Filter screen; 4. Vibrator structure 4-1. Support frame; 4-2. Mounting base; 4-3. Vibrator; 5. Conveyor belt structure; 5-1. First rotating shaft; 5-2. Second rotating shaft; 5-3. Conveyor belt; 5-4. First motor; 6. Counter-knocking structure; 6-1. Auxiliary plate; 6-2. First mounting rod; 6-3. Moving plate; 6-4. Second mounting rod; 6-5. Third spring; 6-6. Knocking block; 7. Connecting bracket; 7-1. First mounting plate; 7-2. Second mounting plate; 7-3. Telescopic rod; 7-4. First spring. Detailed Implementation
[0028] The present invention will be further described in detail below with reference to the accompanying drawings and through embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.
[0029] Example 1 is a sand and gravel screening machine, which has the following features:
[0030] Mounting bracket 1;
[0031] Screening box 2 is installed on mounting bracket 1. Screening box 2 is arranged at an angle and is vertically connected. Screen mesh is arranged inside screening box 2 along the length of screening box 2. A material discharge structure 3 is installed at the upper end of screening box 2. A material discharge port is provided at the lower end of screening box 2 at the position corresponding to the screen mesh.
[0032] The oscillator structure 4 is installed between the screening box 2 and the mounting bracket 1, and can drive the screening box 2 to oscillate on the mounting bracket 1;
[0033] The conveyor belt structure 5 is installed on the mounting bracket 1 at the lower position of the screening box 2, and can transport the material screened out from the screening box 2;
[0034] The counter-tapping structure 6 is installed on the mounting bracket 1 and positioned below the screen of the screening box 2. The counter-tapping structure 6 can move upward and tap the screen inside the screening box 2.
[0035] In this embodiment, after the sand and gravel are fed into the feeding structure 3, they fall into the screening box 2. Under the action of the inclined screen and the vibrator structure 4, the sand and gravel are screened. Large-diameter sand and gravel move on the inclined screen and eventually fall out from the feeding port at the bottom of the screen. Small-diameter sand and gravel fall onto the conveyor belt structure 5 below the screen and are transported out by the conveyor belt structure 5, thus achieving sand and gravel screening. When screen blockage occurs, the counter-impact structure 6 is installed at the corresponding position on the mounting bracket 1. The counter-impact structure 6 can impact the screen upwards to push out the stones at the blockage position.
[0036] Example 2 is a sand and gravel screening machine. Based on Example 1, in this example, a first screen 2-1 and a second screen 2-3 are arranged sequentially from top to bottom inside the screening box 2. The diameter of the first screen 2-1 is larger than that of the second screen 2-3. At the lower end of the screening box 2, a first discharge port 2-2 and a second discharge port 2-4 are respectively provided at positions corresponding to the first screen 2-1 and the second screen 2-3. Thus, sand and gravel with a diameter larger than that of the first screen 2-1 are discharged through the first discharge port 2-2, sand and gravel with a diameter between that of the first screen 2-1 and the second screen 2-3 are discharged through the second discharge port 2-4, and sand and gravel with a diameter smaller than that of the second screen 2-3 are discharged through the conveyor belt structure 5.
[0037] Example 3 is a sand and gravel screening machine. Based on Example 1, in this example, at least two connecting brackets 7 are connected along the length of the screening box 2 between the screening box 2 and the mounting bracket 1. Each connecting bracket 7 has a first mounting plate 7-1 mounted on the mounting bracket 1 and a second mounting plate 7-2 mounted on the screening box 2. A telescopic rod 7-3 is connected between the first mounting plate 7-1 and the second mounting plate 7-2, and a first spring 7-4 is fitted onto the telescopic rod 7-3 between the first mounting plate 7-1 and the second mounting plate 7-2. Thus, when the vibrator structure 4 is running, the telescopic rod 7-3 between the screening box 2 and the mounting bracket guides the movement of the screening box 2, and the first spring 7-4 on the telescopic rod 7-3 provides good shock absorption.
[0038] Example 4 is a sand and gravel screening machine. Based on Example 1, in this example, the conveyor belt structure 5 has a first rotating shaft 5-1 and a second rotating shaft 5-2 mounted on a mounting bracket 1. A conveyor belt 5-3 is installed between the first rotating shaft 5-1 and the second rotating shaft 5-2. A first motor 5-4 is mounted on the mounting bracket 1, and the first rotating shaft 5-1 is connected to the output shaft of the first motor 5-4. Thus, when the first motor 5-4 is running, it can drive the first rotating shaft 5-1 to rotate, and drive the conveyor belt 5-3 to move between the first rotating shaft 5-1 and the second rotating shaft 5-2.
[0039] Example 5 is a sand and gravel screening machine. Based on Example 1, in this example, the material discharge structure 3 has a mounting frame 3-1 that can be installed on the screening box 2. A vertically connected material discharge box 3-2 is installed on the mounting frame 3-1, and a third screen 3-3 is installed inside the material discharge box 3-2.
[0040] A first mounting hole 3-4 is provided on the side wall of the material discharge box 3-2. A second motor 3-5 is installed in the first mounting hole 3-4. A fan blade 3-6 is installed on the output shaft of the second motor 3-5. A filter screen 3-7 is installed in the first mounting hole 3-4. In this way, the sand and gravel to be screened are put into the material discharge box 3-2, and the sand and gravel are buffered by the third screen 3-3. During the buffering process, the sand and gravel are simply dried by a dryer.
[0041] Example 6 is a sand and gravel screening machine. Based on Example 1, in this example, the vibrator structure 4 has a mounting base 4-2 mounted on the mounting bracket 1 via a support frame 4-1. A vibrator 4-3 is mounted on the mounting base 4-2 and is connected to the screening box 2.
[0042] A slot 1-1 is formed on the mounting bracket 1, and the support frame 4-1 is fitted into the slot 1-1 of the mounting bracket 1. In this way, when the vibrator 4-3 is running, it can drive the screening box 2 to vibrate on the mounting bracket 1, thereby screening the material on the screening box 2.
[0043] Example 7 is a sand and gravel screening machine. Based on Example 1, in this example, the counter-knocking structure 6 has an auxiliary plate 6-1 and a moving plate 6-3. The moving plate 6-3 and the auxiliary plate 6-1 are connected by a third spring 6-5. A knocking block 6-6 is installed on the upper surface of the moving plate 6-3. A first mounting rod 6-2 and a second mounting rod 6-4 are installed on the side walls of the auxiliary plate 6-1 and the moving plate 6-3. The side walls of the mounting bracket 1 are provided with positions corresponding to the first mounting rod 6-2 and the second mounting rod 6-4. The first slide 1-2 and the second slide 1-4 are arranged along the length of the screening box 2. The first mounting rod 6-2 and the second mounting rod 6-4 extend out of the mounting bracket 1 through the first slide 1-2 and the second slide 1-4 respectively. The lower side wall of the first slide 1-2 is provided with a number of first limiting grooves 1-3 that can cooperate with the first mounting rod 6-2 along the length of the first slide 1-2. The upper side wall of the second slide 1-4 is provided with a number of second limiting grooves 1-5 that can cooperate with the second mounting rod 6-4 along the length of the second slide 1-4.
[0044] Both the first mounting rod 6-2 and the second mounting rod 6-4 are threaded, and are respectively mounted on the auxiliary plate 6-1 and the movable plate 6-3 via threaded engagement. Thus, the movable plate 6-3 and the auxiliary plate 6-1, connected by the third spring 6-5, are positioned below the screening box 2 on the mounting bracket 1. The first mounting rod 6-2 and the second mounting rod 6-4 are passed through the first sliding groove 1-2 and the second sliding groove 1-4, and then threaded onto the auxiliary plate 6-1 and the movable plate 6-3. The engagement of the first mounting rod 6-2 with the first sliding groove 1-2 and the second mounting rod 6-4 with the second sliding groove 1-4 moves the auxiliary plate 6-1 and the movable plate 6-3 to their corresponding positions, and the first mounting rod 6-2 engages with the first limiting groove 1-3... The second mounting rod 6-4 and the second limiting groove 1-5 are used to install the counter-knocking structure 6 on the mounting bracket 1. By pressing down the second mounting rod 6-4, the moving plate 6-3 moves towards the auxiliary plate 6-1, and the third spring 6-5 is compressed. After releasing the second mounting rod 6-4, the moving plate 6-3 moves upward under the action of the third spring 6-5. The knocking block 6-6 on the moving plate 6-3 will hit the screen in the screening box 2, pushing out the stones at the blocked position. This reduces the likelihood of stones blocking the screen position after the sand and gravel screening machine is used, which would prevent the screen from performing sand and gravel screening operations.
[0045] Example 8 is a sand and gravel screening machine. In this example, it has the following features:
[0046] Mounting bracket 1;
[0047] Screening box 2 is installed on mounting bracket 1. Screening box 2 is arranged at an angle and is vertically connected. Screen mesh is arranged inside screening box 2 along the length of screening box 2. A material discharge structure 3 is installed at the upper end of screening box 2. A material discharge port is provided at the lower end of screening box 2 at the position corresponding to the screen mesh.
[0048] The oscillator structure 4 is installed between the screening box 2 and the mounting bracket 1, and can drive the screening box 2 to oscillate on the mounting bracket 1;
[0049] The conveyor belt structure 5 is installed on the mounting bracket 1 at the lower position of the screening box 2, and can transport the material screened out from the screening box 2;
[0050] The counter-tapping structure 6 is installed on the mounting bracket 1 and positioned below the screen of the screening box 2. The counter-tapping structure 6 can move upward and tap the screen inside the screening box 2.
[0051] Inside the screening box 2, a first screen 2-1 and a second screen 2-3 are arranged sequentially from top to bottom. The screen diameter of the first screen 2-1 is larger than that of the second screen 2-3. At the lower end of the screening box 2, a first discharge port 2-2 and a second discharge port 2-4 are respectively arranged at positions corresponding to the first screen 2-1 and the second screen 2-3.
[0052] At least two connecting brackets 7 are connected between the screening box 2 and the mounting bracket 1 along the length of the screening box 2. The connecting bracket 7 has a first mounting plate 7-1 mounted on the mounting bracket 1 and a second mounting plate 7-2 mounted on the screening box 2. A telescopic rod 7-3 is connected between the first mounting plate 7-1 and the second mounting plate 7-2. A first spring 7-4 is fitted on the telescopic rod 7-3 between the first mounting plate 7-1 and the second mounting plate 7-2.
[0053] The conveyor belt structure 5 has a first rotating shaft 5-1 and a second rotating shaft 5-2 mounted on the mounting bracket 1. A conveyor belt 5-3 is installed between the first rotating shaft 5-1 and the second rotating shaft 5-2. A first motor 5-4 is mounted on the mounting bracket 1. The first rotating shaft 5-1 is connected to the output shaft of the first motor 5-4.
[0054] The material discharge structure 3 has a mounting frame 3-1 that can be installed on the screening box 2. A material discharge box 3-2 that runs vertically through the material discharge box 3-2 is installed on the mounting frame 3-1. A third screen 3-3 is installed inside the material discharge box 3-2.
[0055] A first mounting hole 3-4 is provided on the side wall of the material box 3-2. A second motor 3-5 is installed in the first mounting hole 3-4. A fan blade 3-6 is installed on the output shaft of the second motor 3-5. A filter screen 3-7 is installed in the first mounting hole 3-4.
[0056] The oscillator structure 4 has a mounting base 4-2 mounted on the mounting bracket 1 via a support frame 4-1, and a vibrator 4-3 is mounted on the mounting base 4-2. The vibrator 4-3 is connected to the screening box 2.
[0057] A slot 1-1 is formed on the mounting bracket 1, and the support frame 4-1 is fitted into the slot 1-1 of the mounting bracket 1.
[0058] The anti-knocking structure 6 has an auxiliary plate 6-1 and a movable plate 6-3. The movable plate 6-3 is connected to the auxiliary plate 6-1 by a third spring 6-5. A knocking block 6-6 is installed on the upper surface of the movable plate 6-3. A first mounting rod 6-2 and a second mounting rod 6-4 are installed on the side walls of the auxiliary plate 6-1 and the movable plate 6-3. A first mounting rod 6-2 is formed on the side walls of the mounting bracket 1 at positions corresponding to the first mounting rod 6-2 and the second mounting rod 6-4, arranged along the length of the sieve box 2. The first mounting rod 6-2 and the second mounting rod 6-4 extend out of the mounting bracket 1 through the first sliding groove 1-2 and the second sliding groove 1-4 respectively. The lower side wall of the first sliding groove 1-2 is provided with a plurality of first limiting grooves 1-3 that can cooperate with the first mounting rod 6-2 along the length direction of the first sliding groove 1-2. The upper side wall of the second sliding groove 1-4 is provided with a plurality of second limiting grooves 1-5 that can cooperate with the second mounting rod 6-4 along the length direction of the second sliding groove 1-4.
[0059] Both the first mounting rod 6-2 and the second mounting rod 6-4 are threaded. The first mounting rod 6-2 and the second mounting rod 6-4 are respectively mounted on the auxiliary plate 6-1 and the movable plate 6-3 through threaded engagement.
[0060] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.
Claims
1. A sand and gravel screening machine, characterized in that: It has: a mounting bracket (1); a screening box (2), which is mounted on the mounting bracket (1), the screening box (2) is inclined and the screening box (2) is vertically connected, the screening box (2) is arranged with a screen along the length of the screening box (2), a material dropping structure (3) is installed at the upper end of the screening box (2), and a material dropping port is set at the lower end of the screening box (2) at the position corresponding to the screen; a vibrator structure (4), which is installed between the screening box (2) and the mounting bracket (1) and can drive the screening box (2) to vibrate on the mounting bracket (1); a conveyor belt structure (5), which is installed on the mounting bracket (1) at the lower position of the screening box (2) and can transport the material screened from the screening box (2); and a knocking structure (6), which is installed on the mounting bracket (1) and arranged at the lower position of the screen of the screening box (2). The knocking structure (6) can move upward and knock the screen inside the screening box (2).
2. The sand and gravel screening machine according to claim 1, characterized in that: A first screen (2-1) and a second screen (2-3) are arranged sequentially from top to bottom inside the screening box (2). The screen diameter of the first screen (2-1) is larger than that of the second screen (2-3). A first discharge port (2-2) and a second discharge port (2-4) are respectively arranged at the lower end of the screening box (2) at positions corresponding to the first screen (2-1) and the second screen (2-3).
3. The sand and gravel screening machine according to claim 1, characterized in that: At least two connecting brackets (7) are connected between the screening box (2) and the mounting bracket (1) along the length of the screening box (2). The connecting bracket (7) has a first mounting plate (7-1) mounted on the mounting bracket (1) and a second mounting plate (7-2) mounted on the screening box (2). A telescopic rod (7-3) is connected between the first mounting plate (7-1) and the second mounting plate (7-2). A first spring (7-4) is fitted on the telescopic rod (7-3) between the first mounting plate (7-1) and the second mounting plate (7-2).
4. The sand and gravel screening machine according to claim 1, characterized in that: The conveyor belt structure (5) has a first rotating shaft (5-1) and a second rotating shaft (5-2) mounted on a mounting bracket (1), a conveyor belt (5-3) is installed between the first rotating shaft (5-1) and the second rotating shaft (5-2), a first motor (5-4) is mounted on the mounting bracket (1), and the first rotating shaft (5-1) is connected to the output shaft of the first motor (5-4).
5. A sand and gravel screening machine according to claim 1, characterized in that: The material feeding structure (3) has a mounting frame (3-1) that can be installed on the screening box (2), and a vertically through material feeding box (3-2) is installed on the mounting frame (3-1), and a third screen (3-3) is installed inside the material feeding box (3-2).
6. A sand and gravel screening machine according to claim 5, characterized in that: A first mounting hole (3-4) is provided on the side wall of the material box (3-2). A second motor (3-5) is installed in the first mounting hole (3-4). A fan blade (3-6) is installed on the output shaft of the second motor (3-5). A filter screen (3-7) is installed in the first mounting hole (3-4).
7. A sand and gravel screening machine according to claim 1, characterized in that: The oscillator structure (4) has a mounting base (4-2) mounted on a mounting bracket (1) via a support frame (4-1), and a vibrator (4-3) is mounted on the mounting base (4-2), the vibrator (4-3) being connected to the sieve box (2).
8. A sand and gravel screening machine according to claim 7, characterized in that: A slot (1-1) is made on the mounting bracket (1), and the support frame (4-1) is fitted into the slot (1-1) of the mounting bracket (1).
9. A sand and gravel screening machine according to claim 1, characterized in that: The counter-knocking structure (6) has an auxiliary plate (6-1) and a movable plate (6-3). The movable plate (6-3) is connected to the auxiliary plate (6-1) by a third spring (6-5). A knocking block (6-6) is installed on the upper surface of the movable plate (6-3). A first mounting rod (6-2) and a second mounting rod (6-4) are installed on the side walls of the auxiliary plate (6-1) and the movable plate (6-3). On the side walls of the mounting bracket (1), at positions corresponding to the first mounting rod (6-2) and the second mounting rod (6-4), a first mounting rod (6-6) is formed along the length direction of the sieve box (2). A first sliding groove (1-2) and a second sliding groove (1-4) are provided. The first mounting rod (6-2) and the second mounting rod (6-4) extend out of the mounting bracket (1) through the first sliding groove (1-2) and the second sliding groove (1-4) respectively. The lower side wall of the first sliding groove (1-2) is provided with a number of first limiting grooves (1-3) that can cooperate with the first mounting rod (6-2) along the length direction of the first sliding groove (1-2). The upper side wall of the second sliding groove (1-4) is provided with a number of second limiting grooves (1-5) that can cooperate with the second mounting rod (6-4) along the length direction of the second sliding groove (1-4).
10. A sand and gravel screening machine according to claim 9, characterized in that: Both the first mounting rod (6-2) and the second mounting rod (6-4) are threaded. The first mounting rod (6-2) and the second mounting rod (6-4) are respectively mounted on the auxiliary plate (6-1) and the movable plate (6-3) through threaded engagement.