A sand and gravel screening device for road construction

Abstract

The present invention relates to the technical field of sand and gravel screening, and specifically to a sand and gravel screening device for road construction, comprising a vibrating screen body for screening sand and gravel in road construction, wherein the vibrating screen body comprises an outer shell, a bottom screen installed inside the outer shell, two groups of support frames arranged outside the outer shell, support springs installed on the support frames, and side plates installed on the support springs; the sand and gravel screening device for road construction, through a filtering and screening mechanism, the gaps between the first screening bar, a plurality of second screening bars, and a plurality of third screening bars in the filtering and screening mechanism can perform preliminary screening on the sand and gravel, and during screening, the gaps between the first screening bar, a plurality of second screening bars, and a plurality of third screening bars can be adjusted to prevent the smaller side of irregular stones from contacting the gap and clogging the gap, and at the same time, the stones located in the gap can be directly crushed, thereby further improving the screening efficiency of the sand and gravel, and facilitating the use of the sand and gravel in road construction.

Description

Technical Field

[0001] The invention relates to the technical field of sand and gravel screening, in particular to a sand and gravel screening device for road construction. Background Art

[0002] In road construction, gravel is an indispensable material used for laying roadbeds, pavements, etc. However, gravel directly obtained from the excavation site often contains stones of different sizes, which need to be screened to ensure the quality and applicability of the gravel. Screening gravel can remove impurities and large stones that do not meet the requirements, improve the uniformity and stability of gravel, and thus meet the quality requirements of road construction.

[0003] At present, when screening sand and gravel, a vibrating screen is often used for screening sand and gravel. For example, the existing Chinese patent application number: CN202122781071.8 discloses: a new type of vibrating screen, the upper screen of which is composed of a plurality of strip metal plates, and a certain gap is set between the plurality of strip metal plates. Through the vibration of the vibrating screen, sand and gravel that meet the screening size fall from the gap. However, in the actual sand and gravel screening process, due to the irregular shape of the stone, the smaller side of the stone contacts the gap during the vibration of the vibrating screen, causing the stone to be stuck, thereby affecting the screening of sand and gravel. Summary of the invention

[0004] The object of the present invention is to provide a sand and gravel screening device for road construction to solve the problems raised in the above background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a sand and gravel screening device for road construction, comprising a vibrating screen body for screening sand and gravel in road construction, the vibrating screen body comprising an outer shell, a bottom screen installed inside the outer shell, two groups of support frames arranged outside the outer shell, support springs installed on the support frames, side plates installed on the support springs, a rotating shaft passing through the outer shell, an eccentric wheel fixedly installed on the rotating shaft and located outside the outer shell, and a rotating mechanism for driving the eccentric wheel, a plurality of the side plates are fixedly installed on the outer shell, a filtering and screening mechanism is provided inside the outer shell and above the bottom screen, the filtering and screening mechanism is used to perform preliminary screening of sand and gravel and crush the sand and gravel at the same time;

[0006] The filtering and screening mechanism also includes a first screening bar, a plurality of second screening bars sequentially arranged on the left side of the first screening bar, a third screening bar sequentially arranged on the right side of the first screening bar, and a driving mechanism;

[0007] The driving mechanism is installed inside the shell, and the driving mechanism drives the first screening bar to adjust the gaps between the plurality of first screening bars and the plurality of second screening bars, thereby squeezing and crushing the sand and gravel stuck in the plurality of gaps to prevent sand and gravel from being blocked.

[0008] Furthermore, a plurality of cutting bars are fixedly installed on both sides of the outside of the first screening bar, the second screening bar and the third screening bar, and the sand and gravel are crushed by the plurality of cutting bars being squeezed close to each other.

[0009] Further, the driving mechanism includes a first moving block, a second moving block, a moving mechanism, a synchronous rotation mechanism, a support shaft and a connecting mechanism, wherein two first moving blocks are provided, and the two first moving blocks are respectively fixedly installed at the two ends of the bottom of the first screening bar, and the second moving blocks are fixedly installed at both ends of the bottom of the second screening bar and the third screening bar;

[0010] The moving mechanism is located on the housing and synchronously drives the two first moving blocks, and the plurality of second moving blocks are slidably connected to the moving mechanism;

[0011] The synchronous rotating mechanism synchronously drives the moving mechanism to drive;

[0012] The support shaft is fixedly installed at the bottom of the first moving block, and two connecting mechanisms are provided. One connecting mechanism is arranged between the second moving blocks at the bottom of multiple second screening bars and is connected to the support shaft, and the other connecting mechanism is arranged between the second moving blocks at the bottom of multiple third screening bars and is connected to the support shaft. Through the provided driving mechanism, the first screening bar can be moved while driving the multiple second screening bars and the multiple third screening bars on its outside to move synchronously, thereby realizing the function of adjusting the gap between the screening bars.

[0013] The moving mechanism comprises a reciprocating screw, a connecting rod, a sliding rod and a threaded sleeve, wherein two reciprocating screws are provided, and four connecting rods are provided, and the four connecting rods are fixedly mounted at both ends of the two reciprocating screws in pairs, and the reciprocating screws are rotatably connected to the housing through the connecting rods at both ends thereof, wherein one end of the two connecting rods penetrates one side of the housing and is connected to the synchronous rotation mechanism;

[0014] A moving hole is provided on the first moving block, and a threaded sleeve is fixedly inserted through the moving hole. The first moving block is threadedly sleeved on the outside of the reciprocating screw through the threaded sleeve, and a plurality of the second moving blocks are slidably sleeved on the outside of the connecting rod;

[0015] There are four sliding rods, and the four sliding rods are distributed in pairs on the outside of the two reciprocating screws. The first moving block and multiple second moving blocks are all slidably connected to the outside of two adjacent sliding rods. Through the provided moving mechanism, the two first moving blocks are synchronously driven.

[0016] Furthermore, the synchronous rotation mechanism includes a first rotating gear, a gear belt and a second rotating gear, two first rotating gears are provided, and the two first rotating gears are respectively fixedly mounted on one end of two connecting rods;

[0017] The second rotating gear is fixedly sleeved on the outside of one of the rotating shafts, and the second rotating gear is located on the outside of the shell. The gear belt transmission is connected to the outside of the second rotating gear and the two first rotating gears, and the synchronous rotation mechanism is provided to achieve the effect of synchronous rotation of two of the connecting rods.

[0018] Further, the connection mechanism includes a first connection support rod, a second connection support rod, a third connection support rod and a fourth connection support rod, one end of the first connection support rod is rotatably sleeved on the outside of the support shaft, and the second connection support rod and the third connection support rod are each provided with a plurality of them, and the plurality of the second connection support rods and the plurality of the third connection support rods are distributed in a V shape between each other, and the plurality of the second connection support rods and the plurality of the third connection support rods are hinged to each other through a pin shaft; and the plurality of the second connection support rods and the plurality of the third connection support rods are hinged to the second moving block adjacent to them through a pin shaft;

[0019] One of the second connecting rods is hinged to one end of the first connecting rod through a pin;

[0020] One of the third connecting struts is hinged to the fourth connecting strut via a pin, and the fourth connecting strut is rotatably connected to the inside of the shell via a pin, so as to achieve the function of synchronously driving the first moving block and the multiple second moving blocks on the left side or the multiple second moving blocks on the right side through a connection mechanism.

[0021] Furthermore, two grooves are provided on both sides of the interior of the shell, and one end of the fourth connecting rod is rotatably connected to the groove through a pin shaft, thereby achieving the function of connecting the fourth connecting rod.

[0022] Furthermore, two guide mechanisms are installed inside the shell, and the two guide mechanisms are used to guide the first screening bar, the plurality of second screening bars and the plurality of third screening bars.

[0023] Furthermore, the guide mechanism includes a guide rod fixedly installed inside the outer shell, and guide blocks respectively arranged at the bottom of the first screening bar, the second screening bar and the third screening bar. A plurality of the guide blocks are slidably sleeved on the outside of the guide rod, thereby achieving the function of auxiliary support for the first screening bar, the second screening bar and the third screening bar.

[0024] Furthermore, the first screening bar, the second screening bar and the third screening bar are all fixedly installed with connecting plates at the bottom, the connecting plate is sleeved with a connecting shell at the bottom, and the connecting shell is threaded with locking bolts for locking the connecting plate. The first screening bar, the second screening bar and the third screening bar are all connected to the driving mechanism through the connecting shell at the bottom, thereby facilitating the disassembly and replacement of the first screening bar, the second screening bar and the third screening bar.

[0025] The present invention has at least the following beneficial effects:

[0026] When the present invention is in use, through the filtering and screening mechanism provided, the gaps between the first screening bar, multiple second screening bars and multiple third screening bars in the filtering and screening mechanism can perform preliminary screening on sand and gravel, and while screening, the gaps between them can be adjusted to prevent the smaller side of irregular stones from contacting the gaps and clogging the gaps, and at the same time, the stones located in the gaps can be directly crushed, further improving the screening efficiency of sand and gravel, and facilitating the use of sand and gravel in road construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 It is a side view schematic diagram of the overall mechanism of the present invention;

[0029] Figure 3 It is a top view of the overall structure of the present invention;

[0030] Figure 4 This is a schematic diagram of the eccentric wheel structure of the present invention;

[0031] Figure 5 This is a schematic diagram of the internal structure of the housing of the present invention;

[0032] Figure 6 For the present invention Figure 5 A schematic diagram of the enlarged structure of the middle A area;

[0033] Figure 7 For the present invention Figure 5 Schematic diagram of the enlarged structure of the middle B area;

[0034] Figure 8 This is a schematic diagram of the front view structure of the housing of the present invention;

[0035] Fig. 9 For the present invention Figure 8 Schematic diagram of the enlarged structure of the middle C area;

[0036] Fig.10 It is a schematic diagram of the structure of the first screening bar, the second screening bar and the third screening bar of the present invention;

[0037] Fig.11 It is a schematic diagram of the structure of the mobile mechanism of the present invention;

[0038] Fig.12 For the present invention Fig.11 Schematic diagram of the enlarged structure of the middle D area;

[0039] Fig.13 It is a schematic diagram of the explosion structure of the connecting plate and the connecting shell of the present invention.

[0040] In the figure: 1, vibrating screen body; 11, shell; 111, groove; 12, bottom screen; 13, support frame; 14, support spring; 15, side plate; 16, rotating shaft; 17, eccentric wheel; 18, rotating mechanism; 2, filtering and screening mechanism; 3, first screening bar; 4, second screening bar; 5, third screening bar; 6, driving mechanism; 61, first moving block; 611, moving hole; 62, second moving block; 63, moving mechanism; 631, reciprocating screw; 632, connecting Rod; 633, sliding rod; 634, threaded sleeve; 64, synchronous rotation mechanism; 641, first rotating gear; 642, gear belt; 643, second rotating gear; 65, supporting shaft; 66, connecting mechanism; 661, first connecting support rod; 662, second connecting support rod; 663, third connecting support rod; 664, fourth connecting support rod; 7, cutting strip; 8, guiding mechanism; 81, guide rod; 82, guide block; 9, connecting plate; 91, connecting shell; 92, locking bolt. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] Embodiment 1

[0043] See also Figure 1-Figure 3A sand and gravel screening device for road construction comprises a vibrating screen body 1 for screening sand and gravel in road construction, the vibrating screen body 1 comprises a shell 11, a bottom screen 12 installed inside the shell 11, two sets of support frames 13 arranged outside the shell 11, support springs 14 installed on the support frames 13, side plates 15 installed on the support springs 14, a rotating shaft 16 penetrating the shell 11, an eccentric wheel 17 fixedly installed on the rotating shaft 16 and located outside the shell 11, and a rotating mechanism 18 for driving the eccentric wheel 17, a plurality of side plates 15 are fixedly installed on the outside of the shell 11, that is, when the eccentric wheel 17 rotates, the rotating shaft 16 thereon is synchronously driven to rotate relative to the shell 11, and due to the rotation of the eccentric wheel 17, the shell 11 supported by the support springs 14 vibrates, so that the shell 11 performs a vibration screening effect on the sand and gravel inside the shell 11;

[0044] At the same time, in actual use, the bottom screen 12 structure inside the housing 11 can also be set to a structure consisting of a first screening bar 3, a plurality of second screening bars 4 and a plurality of third screening bars 5, and the gap in this state is adjusted accordingly;

[0045] The rotating mechanism 18 in this embodiment is an existing fixed seat, a servo motor and a coupling, that is, the fixed seat is installed on the outside of the housing 11, and the servo motor is fixedly installed on the fixed seat, and the servo motor is connected to the corresponding eccentric wheel 17 through the coupling, so that the servo motor is operated, so that the output end thereof drives the coupling to rotate, and the coupling is not affected by the vibration of the housing 11 and synchronously drives the eccentric wheel 17 to rotate. A filtering and screening mechanism 2 is provided inside the housing 11 and above the bottom screen 12, and the filtering and screening mechanism 2 is used for preliminary screening of sand and gravel and crushing the sand and gravel at the same time;

[0046] See also Figure 3-Figure 4 as well as Fig.10 The filtering and screening mechanism 2 also includes a first screening bar 3, a plurality of second screening bars 4 sequentially arranged on the left side of the first screening bar 3, a third screening bar 5 sequentially arranged on the right side of the first screening bar 3, and a driving mechanism 6. In this embodiment, the first screening bar 3, the second screening bar 4 and the third screening bar 5 are all made of high-strength metal materials, thereby ensuring that the first screening bar 3, the screening bar and the third screening bar 5 can screen sand and gravel while ensuring their own strength;

[0047] The driving mechanism 6 is installed inside the housing 11, and the driving mechanism 6 drives the first screening bar 3 to adjust the gap between the first screening bar 3 and the plurality of second screening bars 4, thereby squeezing and crushing the sand and gravel stuck in the plurality of gaps to prevent sand and gravel from being blocked.

[0048] A plurality of cutting bars 7 are fixedly installed on both sides of the outside of the first screening bar 3, the second screening bar 4 and the third screening bar 5. The cutting bars 7 are made of high-strength metal material, so that stones stuck in the gaps can be squeezed and crushed in a certain size of gap, and the sand and gravel can be crushed by squeezing the plurality of cutting bars 7 close to each other.

[0049] See also Figure 4-Figure 6 , Figure 8 , Fig. 9 and Figure 11-Figure 12 The driving mechanism 6 includes a first moving block 61, a second moving block 62, a moving mechanism 63, a synchronous rotation mechanism 64, a support shaft 65 and a connecting mechanism 66. Two first moving blocks 61 are provided. The two first moving blocks 61 are respectively fixedly installed at the two ends of the bottom of the first screening bar 3, and the second moving blocks 62 are fixedly installed at both ends of the bottom of the second screening bar 4 and the third screening bar 5;

[0050] The moving mechanism 63 is located on the housing 11 and synchronously drives the two first moving blocks 61, and the plurality of second moving blocks 62 are slidably connected to the moving mechanism 63;

[0051] The synchronous rotating mechanism 64 synchronously drives the moving mechanism 63 to drive;

[0052] The support shaft 65 is fixedly installed at the bottom of the first moving block 61, and two connecting mechanisms 66 are provided. One connecting mechanism 66 is arranged between the second moving blocks 62 at the bottom of multiple second screening bars 4 and is connected to the support shaft 65, and the other connecting mechanism 66 is arranged between the second moving blocks 62 at the bottom of multiple third screening bars 5 and is connected to the support shaft 65.

[0053] See also Figure 10-12 The moving mechanism 63 includes a reciprocating screw 631, a connecting rod 632, a sliding rod 633 and a threaded sleeve 634. There are two reciprocating screws 631, and four connecting rods 632. The four connecting rods 632 are fixedly installed at both ends of the two reciprocating screws 631 in pairs. The reciprocating screw 631 is rotatably connected to the housing 11 through the connecting rods 632 at both ends, wherein one end of the two connecting rods 632 passes through one side of the housing 11 and is connected to the synchronous rotation mechanism 64;

[0054] The first moving block 61 is provided with a moving hole 611, and a threaded sleeve 634 is fixedly passed through the moving hole 611. The first moving block 61 is threadedly sleeved on the outside of the reciprocating screw 631 through the threaded sleeve 634, and the plurality of second moving blocks 62 are slidably sleeved on the outside of the connecting rod 632;

[0055] There are four slide bars 633 , and the four slide bars 633 are distributed in pairs on the outside of the two reciprocating screws 631 . The first moving block 61 and the plurality of second moving blocks 62 are all slidably sleeved on the outside of two adjacent slide bars 633 .

[0056] See also Figure 4 The synchronous rotation mechanism 64 includes a first rotating gear 641, a gear belt 642, and a second rotating gear 643. Two first rotating gears 641 are provided. The two first rotating gears 641 are respectively fixedly mounted on one end of two connecting rods 632. One end of the connecting rod 632 passes through one side of the housing 11, and the connecting rod 632 is rotatably connected to the housing 11 through a bearing.

[0057] The second rotating gear 643 is fixedly sleeved on the outside of one of the rotating shafts 16, and the second rotating gear 643 is located on the outside of the housing 11, and the gear belt 642 is transmission-connected to the second rotating gear 643 and the outside of the two first rotating gears 641, that is, when one of the rotating shafts 16 rotates, the second rotating gear 643 is synchronously driven to rotate, and when the second rotating gear 643 rotates, the gear belt 642 further drives the two first rotating gears 641 to rotate synchronously, and when the two first rotating gears 641 rotate synchronously, the connecting rod 632 further drives the reciprocating screw 631 thereon to rotate;

[0058] At the same time, in this embodiment, a synchronous rotation mechanism 64 is set, which is driven by one of the rotating shafts 16, so there is no need to add additional driving force, which not only saves energy consumption, but also prevents the continuous vibration of the shell 11 when an additional motor or drive is added, which affects the service life of the motor or drive.

[0059] See also Figure 11 to Figure 12 The connecting mechanism 66 includes a first connecting rod 661, a second connecting rod 662, a third connecting rod 663 and a fourth connecting rod 664. One end of the first connecting rod 661 is rotatably sleeved on the outside of the support shaft 65. A plurality of second connecting rods 662 and a plurality of third connecting rods 663 are provided. The plurality of second connecting rods 662 and the plurality of third connecting rods 663 are distributed in a V shape in pairs. The plurality of second connecting rods 662 and the plurality of third connecting rods 663 are hinged to each other through pins; and the plurality of second connecting rods 662 and the plurality of third connecting rods 663 are hinged to the adjacent second moving block 62 through pins.

[0060] One of the second connecting rods 662 is hinged to one end of the first connecting rod 661 through a pin;

[0061] One of the third connecting rods 663 is hinged to the fourth connecting rod 664 through a pin, and the fourth connecting rod 664 is rotatably connected to the inside of the shell 11 through the pin. Two grooves 111 are provided on both sides of the inside of the shell 11, and one end of the fourth connecting rod 664 is rotatably connected to the groove 111 through the pin.

[0062] Two guide mechanisms 8 are installed inside the housing 11 , and the two guide mechanisms 8 are used to guide the first screening bar 3 , the plurality of second screening bars 4 , and the plurality of third screening bars 5 .

[0063] See also Figure 5 and Figure 7 The guide mechanism 8 includes a guide rod 81 fixedly installed inside the shell 11, and guide blocks 82 respectively arranged at the bottom of the first screening bar 3, the second screening bar 4 and the third screening bar 5, and multiple guide blocks 82 are slidably sleeved on the outside of the guide rod 81.

[0064] Specific implementation process: During the road construction process, when screening sand and gravel, the sand and gravel are introduced into one end of the vibrating screen body 1, and two servo motors are operated synchronously, so that the eccentric wheel 17 is swung, so that the shell 11 is supported by the support spring 14 to vibrate relatively, so as to achieve preliminary screening of the sand and gravel on the first screening bar 3, the plurality of second screening bars 4 and the plurality of third screening bars 5, and the screened sand and gravel are then screened twice through the bottom screen 12 inside the shell 11;

[0065] In the process of vibrating and screening the sand and gravel and vibrating and moving downward along the inclined shell 11, as the eccentric wheel 17 rotates, the two connecting rods 632 drive the reciprocating screws 631 thereon to rotate synchronously under the drive of the synchronous rotation mechanism 64. While the two reciprocating screws 631 rotate, the threaded sleeve 634 at the first moving block 61 at the bottom of the first screening bar 3 receives the driving force, and due to the limiting action of the two sliding rods 633 at the first moving block 61, the first moving block 61 moves leftward or rightward along the inside of the shell 11.

[0066] As the instruction manual Figure 3 That is, the schematic diagram provided in the present invention is a state in which the first moving block 61 moves rightward and to the rightmost end relative to the inside of the shell 11. In this state, due to the connection of the first connecting support rod 661, the second connecting support rod 662, the third connecting support rod 663 and the fourth connecting support rod 664 to the multiple second moving blocks 62 on the left side of the first moving block 61, the gaps between the multiple second screening bars 4 on the left side, the gap between one of the second screening bars 4 close to the inner side of the shell 11 and the gap between one of the second screening bars 4 close to the first screening bar 3 are kept at the maximum. In this state, after the stones in the maximum gap state are squeezed and crushed, the crushed stones fall down, while the larger-sized stones vibrate and fall along the inside of the shell 11;

[0067] The gaps between the third screening bars 5 on the right side, the gap between one of the third screening bars 5 close to the inner side of the housing 11, and the gap between one of the third screening bars 5 close to the first screening bar 3 are kept at the minimum. In this state, the stones stuck in the gaps are squeezed and crushed by the cutting bars 7 between the first screening bar 3 and the third screening bar 5.

[0068] That is, when the first moving block 61 moves to the left or right, the stones blocking the gap can be fully crushed and then fall down, that is, the sieve can be used for screening and prevent the gap from being blocked.

[0069] At the same time, in this embodiment, the settings of the maximum gap and the minimum gap can be set according to the actual sand and gravel screening needs, so as to ensure that the sand and gravel within the size range are screened.

[0070] Embodiment 2

[0071] See also Fig.13 , Example 2 is a further supplementary explanation of Example 1, specifically: the first screening bar 3, the second screening bar 4 and the third screening bar 5 are all fixedly installed with a connecting plate 9 at the bottom, a connecting shell 91 is sleeved on the bottom of the connecting plate 9, and a locking bolt 92 for locking the connecting plate 9 is threadedly connected on the connecting shell 91, and the first screening bar 3, the second screening bar 4 and the third screening bar 5 are all connected to the driving mechanism 6 through the connecting shell 91 at the bottom thereof.

[0072] Therefore, when the first screening bar 3, the second screening bar 4 and the third screening bar 5 or the cutting bar 7 on the screening bar appear to be worn or broken, the first screening bar 3, the second screening bar 4 or the third screening bar 5 can be disassembled and replaced by rotating the locking bolt 92, thereby improving the sand and gravel screening efficiency.

[0073] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0074] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A gravel screening device for road construction, comprising a vibrating screen body (1) for screening gravel in road construction, the vibrating screen body (1) comprising a housing (11), a bottom screen (12) mounted inside the housing (11), two sets of support frames (13) arranged outside the housing (11), support springs (14) mounted on the support frames (13), side plates (15) mounted on the support springs (14), a rotating shaft (16) passing through the housing (11), an eccentric wheel (17) fixedly mounted on the rotating shaft (16) and located outside the housing (11), and a rotating mechanism (18) for driving the eccentric wheel (17), wherein a plurality of the side plates (15) are fixedly mounted outside the housing (11), and characterized in that: A filtering and screening mechanism (2) is provided inside the housing (11) and above the bottom screen (12), wherein the filtering and screening mechanism (2) is used to perform preliminary screening of sand and gravel and crush the sand and gravel at the same time; The filtering and screening mechanism (2) further comprises a first screening bar (3), a plurality of second screening bars (4) arranged in sequence on the left side of the first screening bar (3), a third screening bar (5) arranged in sequence on the right side of the first screening bar (3), and a driving mechanism (6); The driving mechanism (6) is installed inside the housing (11), and the driving mechanism (6) drives the first screening bar (3) to adjust the gaps between the plurality of first screening bars (3) and the plurality of second screening bars (4), thereby squeezing and crushing the sand and gravel stuck in the plurality of gaps to prevent blockage by the sand and gravel; The driving mechanism (6) comprises a first moving block (61), a second moving block (62), a moving mechanism (63), a synchronous rotation mechanism (64), a support shaft (65) and a connecting mechanism (66), wherein two first moving blocks (61) are provided, and the two first moving blocks (61) are respectively fixedly mounted at two ends of the bottom of the first screening bar (3), and second moving blocks (62) are fixedly mounted at two ends of the bottom of the second screening bar (4) and the third screening bar (5); The moving mechanism (63) is located on the housing (11) and synchronously drives the two first moving blocks (61), and the plurality of second moving blocks (62) are slidably connected to the moving mechanism (63); The synchronous rotation mechanism (64) synchronously drives the moving mechanism (63) to be driven; The support shaft (65) is fixedly mounted at the bottom of the first moving block (61), and two connecting mechanisms (66) are provided, one connecting mechanism (66) is arranged between the second moving blocks (62) at the bottom of the plurality of second screening bars (4) and is connected to the support shaft (65), and the other connecting mechanism (66) is arranged between the second moving blocks (62) at the bottom of the plurality of third screening bars (5) and is connected to the support shaft (65).

2. A sand and gravel screening device for road construction according to claim 1, characterized in that: A plurality of cutting bars (7) are fixedly mounted on both sides of the outside of the first screening bar (3), the second screening bar (4) and the third screening bar (5), and the sand and gravel are crushed by the plurality of cutting bars (7) being pressed close to each other.

3. A sand and gravel screening device for road construction according to claim 1, characterized in that: The moving mechanism (63) comprises a reciprocating screw (631), a connecting rod (632), a sliding rod (633) and a threaded sleeve (634), wherein two reciprocating screws (631) are provided, and four connecting rods (632) are provided, and the four connecting rods (632) are fixedly mounted on both ends of the two reciprocating screws (631) in pairs, and the reciprocating screw (631) is rotatably connected to the housing (11) via the connecting rods (632) at both ends thereof, wherein one end of the two connecting rods (632) passes through one side of the housing (11) and is connected to the synchronous rotation mechanism (64); A moving hole (611) is provided on the first moving block (61), and a threaded sleeve (634) is fixedly inserted through the moving hole (611); the first moving block (61) is threadedly sleeved on the outside of the reciprocating screw (631) through the threaded sleeve (634); and a plurality of the second moving blocks (62) are slidably sleeved on the outside of the connecting rod (632); Four sliding rods (633) are provided, and the four sliding rods (633) are distributed in pairs outside the two reciprocating screws (631), and the first moving block (61) and the plurality of second moving blocks (62) are all slidably sleeved on the outsides of two adjacent sliding rods (633).

4. A sand and gravel screening device for road construction according to claim 1, characterized in that: The synchronous rotation mechanism (64) comprises a first rotating gear (641), a gear belt (642) and a second rotating gear (643); two first rotating gears (641) are provided, and the two first rotating gears (641) are respectively fixedly mounted on one end of two of the connecting rods (632); The second rotating gear (643) is fixedly sleeved on the outside of one of the rotating shafts (16), and the second rotating gear (643) is located on the outside of the housing (11), and the gear belt (642) is transmission-connected to the outside of the second rotating gear (643) and the two first rotating gears (641).

5. A sand and gravel screening device for road construction according to claim 1, characterized in that: The connecting mechanism (66) comprises a first connecting support rod (661), a second connecting support rod (662), a third connecting support rod (663) and a fourth connecting support rod (664); one end of the first connecting support rod (661) is rotatably sleeved on the outside of the support shaft (65); a plurality of the second connecting support rods (662) and a plurality of the third connecting support rods (663) are provided; the plurality of the second connecting support rods (662) and the plurality of the third connecting support rods (663) are distributed in a V shape; the plurality of the second connecting support rods (662) and the plurality of the third connecting support rods (663) are hinged to each other through a pin shaft; and the plurality of the second connecting support rods (662) and the plurality of the third connecting support rods (663) are hinged to the adjacent second moving blocks (62) through a pin shaft; One of the second connecting rods (662) is hingedly connected to one end of the first connecting rod (661) via a pin; One of the third connecting rods (663) is hingedly connected to the fourth connecting rod (664) via a pin, and the fourth connecting rod (664) is rotatably connected to the inside of the housing (11) via the pin.

6. A sand and gravel screening device for road construction according to claim 5, characterized in that: Two grooves (111) are provided on both sides of the interior of the housing (11), and one end of the fourth connecting rod (664) is rotatably connected to the groove (111) via a pin.

7. A sand and gravel screening device for road construction according to claim 1, characterized in that: Two guide mechanisms (8) are installed inside the housing (11), and the two guide mechanisms (8) are used to guide the first screening bar (3), the plurality of second screening bars (4), and the plurality of third screening bars (5).

8. A sand and gravel screening device for road construction according to claim 7, characterized in that: The guide mechanism (8) comprises a guide rod (81) fixedly mounted inside the housing (11), and guide blocks (82) respectively arranged at the bottom of the first screening bar (3), the second screening bar (4) and the third screening bar (5), wherein a plurality of the guide blocks (82) are slidably sleeved on the outside of the guide rod (81).

9. A sand and gravel screening device for road construction according to claim 1, characterized in that: A connecting plate (9) is fixedly mounted on the bottom of each of the first screening bar (3), the second screening bar (4) and the third screening bar (5); a connecting shell (91) is sleeved on the bottom of the connecting plate (9); and a locking bolt (92) for locking the connecting plate (9) is threadedly connected to the connecting shell (91); and the first screening bar (3), the second screening bar (4) and the third screening bar (5) are connected to the driving mechanism (6) via the connecting shell (91) at the bottom thereof.

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