An Internet of Things-based traffic patrol drone with real-time positioning function

Abstract

The present invention relates to the technical field of unmanned aerial vehicles, and specifically discloses a traffic patrol unmanned aerial vehicle capable of real-time positioning based on the Internet of Things, including an unmanned aerial vehicle body. A mounting plate is horizontally placed at the bottom of the unmanned aerial vehicle body. A foam board is provided at the bottom of the mounting plate. A buffer mechanism is provided between the top end of the mounting plate and the support arm of the unmanned aerial vehicle body. Airbags are movably installed on both sides of the mounting plate along the length direction. First fixing blocks are installed on both sides of one end of the mounting plate close to the camera of the unmanned aerial vehicle body. By setting up a publicity curtain, a first fan, a second fan and a spring, when the unmanned aerial vehicle body patrols the road, through the warning and guiding slogans on the publicity curtain, it plays a guiding and warning role for pedestrians and vehicles on the road, reducing the occurrence of traffic accidents. When the unmanned aerial vehicle body runs out of power during patrol, the unmanned aerial vehicle body is under the weight of the mounting plate and other mechanisms on the mounting plate.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles, and particularly to a traffic patrol unmanned aerial vehicle based on the Internet of Things and capable of real-time positioning. Background Art

[0002] An unmanned aerial vehicle, abbreviated as "UAV" and with the English abbreviation "UAV", is an unpiloted aircraft controlled by a radio remote control device and a self-prepared program control device, or is completely or intermittently autonomously operated by an on-vehicle computer.

[0003] When a traffic patrol UAV conducts a patrol on a road, if there is an unexpected situation on the road and the UAV cannot return in time when the power runs out, at this time, the UAV loses its power source and will directly fall down, causing damage to the UAV and generating high maintenance costs. Moreover, if the UAV encounters strong wind weather during the patrol process, the stability of the UAV will also be affected, resulting in unclear images captured by the UAV, and the staff cannot timely judge the road conditions, etc. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies in the prior art, and a traffic patrol UAV based on the Internet of Things and capable of real-time positioning is proposed.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A traffic patrol UAV based on the Internet of Things and capable of real-time positioning includes a UAV body. A mounting plate is horizontally placed at the bottom of the UAV body. A foam board is provided at the bottom of the mounting plate. A buffer mechanism is provided between the top end of the mounting plate and the support arm of the UAV body. Airbags are movably mounted on both sides of the mounting plate along the length direction. First fixing blocks are mounted on both sides of one end of the mounting plate close to the camera of the UAV body. A rotating rod is rotatably mounted between the two first fixing blocks. A publicity curtain is wound around the outer side of the rotating rod. A first rotating motor is mounted on one side of one first fixing block. The output end of the first rotating motor movably penetrates through the first fixing block and is connected to the rotating rod. A cleaning mechanism is provided below the camera of the UAV body. A stabilizing mechanism is provided on the top of the mounting plate.

[0007] Preferably, the buffer mechanism includes a first connecting rod, a spring and a second connecting rod. The bottom ends of the support arms of the UAV body are all mounted with first connecting rods. First slots are vertically opened at the bottom ends of the first connecting rods. A second connecting rod is movably inserted into the interior of the first slots. A spring is connected between the top end of the second connecting rod and the top end of the inner wall of the first slots. The bottom end of the second connecting rod is connected to the top end of the mounting plate.

[0008] Preferably, two electric telescopic rods are embedded and installed on both sides of the mounting plate. The telescopic ends of the electric telescopic rods are all away from the mounting plate, and the telescopic ends of the electric telescopic rods are connected to the airbag.

[0009] Preferably, the cleaning mechanism includes a second slot, a third slot and a second fixing block. A second slot is vertically penetrated and opened at the top of the mounting plate near the camera of the UAV body. A third slot is vertically penetrated and opened on one side of the second slot close to the rotating rod. A second fixing block is vertically installed inside the second slot. A first sliding groove is vertically opened on one side of the second fixing block close to the third slot. A first electric slider is slidably installed inside the first sliding groove. One side of the first electric slider away from the first sliding groove is movably connected to a third connecting rod. One end of the third connecting rod away from the first electric slider is connected to a scraper.

[0010] Preferably, a fourth rotating motor is installed at one end of the first electric slider away from the first sliding groove. The output end of the fourth rotating motor is away from the first electric slider. A fifth rotating motor is installed at the output end of the fourth rotating motor. The output end of the fifth rotating motor faces the mounting plate. The output end of the fifth rotating motor is connected to one end of the third connecting rod away from the scraper.

[0011] Preferably, the stabilizing mechanism includes a first blower and a second blower. First blowers are movably installed on both sides of the UAV body at the top end of the mounting plate. A second blower is movably installed at the top of the mounting plate at the end of the UAV body away from the camera.

[0012] Preferably, second rotating motors are embedded and installed at the bottom of the first blowers on the top of the mounting plate, and the output ends of the second rotating motors are respectively connected to the bottom ends of the first blowers. A third rotating motor is embedded and installed at the bottom of the second blower at the top end of the mounting plate, and the output end of the third rotating motor is connected to the bottom end of the second blower.

[0013] Preferably, triangular blocks are vertically installed on both sides of the scraper along the end wall direction. The length direction of the scraper is parallel to the length direction of the third slot, and the length of the scraper is less than the length of the third slot.

[0014] Compared with the prior art, the beneficial effects of the present invention are:

[0015] In the present invention, through the provision of a publicity curtain, a first fan, a second fan and a spring, when the UAV body patrols the road, the warning and guiding slogans on the publicity curtain play a guiding and warning role for pedestrians and vehicles on the road, reducing the occurrence of traffic accidents. When the UAV body runs out of power during patrol, under the weight of the mounting plate and other mechanisms on the mounting plate, the UAV body will show a falling manner with the mounting plate facing downwards. The foam board at the bottom of the mounting plate and the air bags on both sides will absorb part of the impact force when the device lands, and the remaining impact force will act on the second connecting rod. A squeezing force is generated on the spring through the second connecting rod. Through the absorption and conversion of the impact force by the spring, the impact force is further reduced, playing a further buffering role for the impact force. Finally, the remaining impact force will act on the support arm of the UAV body, reducing the damage to the UAV body;

[0016] When the UAV body works in strong wind weather, the UAV body will shake. According to the judgment of the wind direction, the corresponding first fan or second fan is turned on, so that the UAV body generates a driving force opposite to the wind direction, and the two offset each other, reducing the influence of strong wind on the UAV body and improving the clarity of the UAV body's shooting in strong wind.

[0017] In the present invention, through the provision of a first electric slider, a fourth rotating motor, a fifth rotating motor and a scraper, the scraper is flipped above the first electric slider through the fourth rotating motor, and then the first electric slider moves up and down repeatedly, so that the scraper scrapes off the water droplets on the camera, ensuring the clarity of the camera shooting of the UAV body. When the device falls into the water, the second fan starts, which can make the device generate a driving force. The fourth rotating motor flips the scraper below the first electric slider, and the fifth rotating motor drives the scraper to rotate, so that the rotation of the scraper in the water can play a role in adjusting the direction of the UAV body's forward movement in the water, facilitating the staff to adjust the recovery location of the UAV body.

[0018] In the present invention, through the provision of an air bag and an electric telescopic rod, when the device lands on the ground, the air bag can absorb the landing impact force and play a buffering role. When the device lands on the water surface, the electric telescopic rod drives the air bag to extend outwards, increasing the floating area of the mounting plate on the water surface, preventing the UAV body from tipping over during the forward movement, and increasing the use safety of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of the overall structure of the present invention;

[0020] Figure 2 is a schematic diagram of the mounting plate structure of the present invention;

[0021] Figure 3 is a schematic diagram of the second fixing block structure of the present invention;

[0022] Figure 4 This is a schematic cross-sectional view of the first connecting rod of the present invention.

[0023] In the figure: 1, UAV body; 2, mounting plate; 3, first connecting rod; 4, first slot; 5, spring; 6, second connecting rod; 7, airbag; 8, electric telescopic rod; 9, first fixing block; 10, rotating rod; 11, first rotating motor; 12, promotional curtain; 13, first fan; 14, second fan; 15, second rotating motor; 16, third rotating motor; 17, second slot; 18, third slot; 19, second fixing block; 20, first chute; 21, first electric slider; 22, fourth rotating motor; 23, fifth rotating motor; 24, third connecting rod; 25, scraper; 26, triangular block. Detailed implementation manners

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0025] Refer to Figures 1-4, An Internet of Things-based traffic patrol drone with real-time positioning function, including a drone body 1. A mounting plate 2 is horizontally placed at the bottom of the drone body 1. A foam board is provided at the bottom of the mounting plate 2. A buffer mechanism is provided between the top end of the mounting plate 2 and the support arm of the drone body 1. Airbags 7 are movably installed on both sides of the mounting plate 2 along the length direction. On both sides of one end of the mounting plate 2 close to the camera of the drone body 1, first fixing blocks 9 are installed. A rotating rod 10 is rotatably installed between the two first fixing blocks 9. A publicity curtain 12 is wound and installed on the outer side of the rotating rod 10. A first rotating motor 11 is installed on one side of one first fixing block 9. The output end of the first rotating motor 11 movably penetrates through the first fixing block 9 and is connected to the rotating rod 10. A cleaning mechanism is provided below the camera of the drone body 1. A stabilizing mechanism is provided on the top of the mounting plate 2. When the drone body 1 patrols the road, during the traffic peak period, the publicity curtain 12 wound and installed on the outer side of the rotating rod 10 is opened. Through the warning and guiding slogans on the publicity curtain 12, it plays a guiding and warning role for pedestrians and vehicles on the road, reducing the occurrence of traffic accidents. When the drone body 1 runs out of power during patrol, under the weight of the mounting plate 2 and other mechanisms on the mounting plate 2, the drone body 1 will fall in a way that the mounting plate 2 faces downwards. The buffer mechanism buffers the impact force when the drone body 1 lands on the ground, playing a protective role for the drone body 1 and reducing the expenditure on maintenance costs when the drone is damaged. In rainy days, the cleaning mechanism scrapes off the water droplets attached to the camera of the drone body 1 to ensure the clarity of shooting. In strong wind weather, through the stabilizing mechanism, the drone body 1 is prevented from shaking violently, resulting in unclear shooting.

[0026] As a technical optimization scheme of the present invention, the buffer mechanism includes a first connecting rod 3, a spring 5 and a second connecting rod 6. The bottom ends of the support arms of the drone body 1 are all installed with first connecting rods 3. A first slot 4 is vertically opened at the bottom end of the first connecting rod 3. A second connecting rod 6 is movably inserted and installed inside the first slot 4. A spring 5 is connected between the top end of the second connecting rod 6 and the top inner wall of the first slot 4. The bottom end of the second connecting rod 6 is connected to the top end of the mounting plate 2. The impact force will act on the second connecting rod 6. Subsequently, the second connecting rod 6 moves in the first slot 4 inside the first connecting rod 3 and generates a squeezing force on the spring 5. Through the absorption and conversion of the impact force by the spring 5, the impact force is further reduced, playing a buffering role for the impact force.

[0027] As a technical optimization scheme of the present invention, two electric telescopic rods 8 are embedded and installed on both sides of the mounting plate 2. The telescopic ends of the electric telescopic rods 8 are all away from the mounting plate 2. The telescopic ends of the electric telescopic rods 8 are connected to the airbags 7. The electric telescopic rods 8 drive the airbags 7 to extend outwards, increasing the floating area of the mounting plate 2 on the water surface, preventing the drone body 1 from tipping over during the forward movement, and increasing the use safety of the device.

[0028]

[0028] As a technical optimization solution of the present invention, the cleaning mechanism includes a second slot 17, a third slot 18 and a second fixing block 19. A second slot 17 is vertically penetrated and opened at the top of the mounting plate 2 near one end of the camera of the UAV body 1. A third slot 18 is vertically penetrated and opened on one side of the second slot 17 close to the rotating rod 10. A second fixing block 19 is vertically installed inside the second slot 17. A first sliding groove 20 is vertically opened on one side of the second fixing block 19 close to the third slot 18. A first electric slider 21 is slidably installed inside the first sliding groove 20. One side of the first electric slider 21 away from the first sliding groove 20 is movably connected to a third connecting rod 24. One end of the third connecting rod 24 away from the first electric slider 21 is connected to a scraper 25. The first electric slider 21 moves up and down repeatedly inside the first sliding groove 20, so that the scraper 25 scrapes off the water droplets on the camera, ensuring the clarity of the image captured by the camera of the UAV body 1.

[0029] As a technical optimization solution of the present invention, a fourth rotating motor 22 is installed at one end of the first electric slider 21 away from the first sliding groove 20. The output end of the fourth rotating motor 22 is away from the first electric slider 21. A fifth rotating motor 23 is installed at the output end of the fourth rotating motor 22. The output end of the fifth rotating motor 23 faces the mounting plate 2. The output end of the fifth rotating motor 23 is connected to one end of the third connecting rod 24 away from the scraper 25. The fourth rotating motor flips the scraper 25 below the first electric slider 21, so that the scraper 25 can freely adjust its direction and does not affect the normal shooting of the camera. The first electric slider 21 moves downward inside the first sliding groove 20, so that the scraper 25 extends into the water surface. The fifth rotating motor 23 drives the scraper 25 to rotate, so that the rotation of the scraper 25 in the water can produce a function of adjusting the direction for the forward movement of the UAV body 1 in the water, facilitating the staff to adjust the recovery location of the UAV body 1.

[0030]

[0029] As a technical optimization solution of the present invention, the stabilizing mechanism includes a first blower 13 and a second blower 14. The first blowers 13 are movably installed on both sides of the UAV body 1 at the top end of the mounting plate 2. The second blower 14 is movably installed at the top of the mounting plate 2 at one end of the UAV body 1 away from the camera. When the UAV body 1 works in strong wind weather, the UAV body 1 will shake. According to the judgment of the wind direction, the corresponding first blower 13 or second blower 14 is turned on, so that the UAV body 1 generates a driving force opposite to the wind direction, and the two cancel each other out, reducing the influence of strong wind on the UAV body 1 and improving the clarity of the image captured by the UAV body 1 in strong wind.

[0031] As a technical optimization solution of the present invention, second rotating motors 15 are embedded and installed at the top of the mounting plate 2 under the bottom of the first blower 13, and the output ends of the second rotating motors 15 are respectively connected to the bottom ends of the first blower 13. A third rotating motor 16 is embedded and installed at the top of the mounting plate 2 under the bottom of the second blower 14, and the output end of the third rotating motor 16 is connected to the bottom end of the second blower 14. By driving the first blower 13 to rotate with the second rotating motor 15 and driving the second blower 14 to rotate with the third rotating motor 16, the air outlet directions of the first blower 13 and the second blower 14 can be slightly adjusted, so that the device can adapt to different wind directions during use, improving the practicability of the device.

[0032] As a technical optimization solution of the present invention, triangular blocks 26 are vertically installed along the end wall direction on both sides of the scraper 25. The length direction of the scraper 25 is parallel to the length direction of the third slot 18, and the length of the scraper 25 is less than the length of the third slot 18. This ensures that the scraper 25 will not interfere with the third slot 18 during rotation, guaranteeing the smooth operation of the device. When the direction of the scraper 25 is adjusted, the triangular block 26 can generate a tangential force with water, reducing the resistance between the scraper 25 and water and increasing the operating speed of the device in water.

[0033] When the present invention is in use, the UAV body 1 can complete its own real-time positioning through the Internet of Things by itself, and this technology is an existing technology, so it will not be described in detail again. The power supply source of the UAV body 1 is separated from the power supply sources of other electrical appliances of this device. The staff controls the UAV body 1 to take off through existing technical products and patrols the road. During the peak traffic congestion period at the commuting time, the first rotating motor 11 is started to drive the rotating rod 10 to rotate, and the publicity curtain 12 wound around the outside of the rotating rod 10 is opened. Through the warning and guiding slogans on the publicity curtain 12, it plays a role of guiding and warning pedestrians and vehicles on the road, reducing the occurrence of traffic accidents. The warning slogans on the publicity curtain 12 are made of photosensitive material, so that the publicity curtain 12 can also be used at night. When the publicity curtain 12 is not in use, only need to drive the rotating rod 10 to rotate through the first rotating motor 11 and wind the publicity curtain 12 again.

[0034] If the drone body 1 encounters strong winds during flight, the drone body 1 will shake due to the wind, causing the picture taken by the drone body 1 to be unclear. At this time, the corresponding first fan 13 or the second fan 14 is turned on according to the judgment of the wind direction, so that the drone body 1 generates a propulsion force opposite to the wind direction, and the two are offset, reducing the impact of the strong wind on the drone body 1 and improving the clarity of the pictures taken by the drone body 1 in strong winds. The first fan 13 is driven to rotate by the second rotating motor 15 and the second fan 14 is driven to rotate by the third rotating motor 16, so that the air outlet direction of the first fan 13 and the second fan 14 can be fine-tuned, so that the device can adapt to different wind directions when in use, thereby improving the practicality of the device.

[0035] When the drone body 1 is working in the rain, the camera is easily attached to rainwater, resulting in unclear shooting. At this time, the fourth rotary motor 22 drives the third connecting rod 24 to rotate, so that the scraper 25 flips to the top of the first electric slider 21, and then the first electric slider 21 moves up and down repeatedly inside the first slide groove 20, so that the scraper 25 scrapes off the water droplets on the camera, ensuring the clarity of the shooting of the camera of the drone body 1.

[0036] When the drone body 1 runs out of power during patrol, the drone body 1 will fall directly downward. At this time, the drone body 1 will fall with the mounting plate 2 facing downward under the counterweight of the mounting plate 2 and other mechanisms on the mounting plate 2, preventing the drone body 1 from directly hitting the ground, causing damage to the drone body 1 and generating considerable repair costs. When the drone body 1 falls on the road, the foam plate at the bottom of the mounting plate 2 and the airbags 7 on both sides of the mounting plate 2 will first contact the ground, forming a first buffer, and the remaining impact force will act on the second connecting rod 6. Then the second connecting rod 6 moves in the first slot 4 inside the first connecting rod 3 and generates an extrusion force on the spring 5. The impact force is further reduced by the absorption and conversion of the impact force by the spring 5. Finally, the remaining impact force will act on the supporting wall of the drone body 1, greatly reducing the damage suffered by the drone body 1 when it falls on the ground and reducing the expenditure of repair costs.

[0037] When the UAV body 1 falls on the water surface, the foam board at the bottom of the mounting plate 2 and the air bags 7 on both sides of the mounting plate 2 can provide a buoyancy at this time, so that the UAV body 1 can float on the water surface and will not directly sink to the bottom of the water, causing damage to the UAV body 1 due to water immersion. When the UAV body 1 floats on the water surface, it is difficult for the staff to recover it. At this time, the second fan 14 is started, so that a driving force is generated on the water surface for the UAV body 1, which can make the UAV body 1 move on the water surface. The first electric slider 21 moves downward inside the first chute 20, so that the scraper 25 extends into the water surface. Subsequently, the fifth rotating motor 23 drives the third connecting rod 24 to rotate, so that the scraper 25 rotates, and the triangular block 26 generates a tangential force with the water during the forward movement of the UAV body 1 in the water. Through the rotation of the triangular block 26 and the scraper 25 in the water, an effect of adjusting the direction can be exerted on the forward movement of the UAV body 1 in the water, so that the UAV body 1 moves to a position convenient for the staff to recover, increasing the convenience of use of the device. During the forward movement of the UAV body 1, the electric telescopic rod 8 extends outward, driving the air bag 7 to move outward, increasing the floating area of the mounting plate 2 on the water surface, preventing the UAV body 1 from tipping over during the forward movement, and increasing the safety of use of the device. It enables the UAV body 1 to float on the water surface, facilitating the positioning system to accurately position the UAV body 1 and improving the positioning accuracy of the UAV body 1.

[0038] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A traffic patrol drone capable of real-time positioning based on the Internet of Things, comprising a drone body (1), characterized in that, A mounting plate (2) is horizontally placed at the bottom of the UAV body (1). A foam board is provided at the bottom of the mounting plate (2). A buffer mechanism is provided between the top end of the mounting plate (2) and the support arm of the UAV body (1). Air bags (7) are movably mounted on both sides of the mounting plate (2) along the length direction. First fixing blocks (9) are mounted on both sides of the mounting plate (2) near one end of the camera of the UAV body (1). A rotating rod (10) is rotatably mounted between the two first fixing blocks (9). A publicity curtain (12) is wound and mounted on the outer side of the rotating rod (10). A first rotating motor (11) is mounted on one side of one first fixing block (9). The output end of the first rotating motor (11) movably penetrates through the first fixing block (9) and is connected to the rotating rod (10). A cleaning mechanism is provided below the camera of the UAV body (1). A stabilizing mechanism is provided on the top of the mounting plate (2). The cleaning mechanism includes a second slot (17), a third slot (18) and a second fixing block (19). A second slot (17) is vertically penetrated and opened at the top of the mounting plate (2) near one end of the camera of the UAV body (1). A third slot (18) is vertically penetrated and opened on one side of the second slot (17) close to the rotating rod (10). A second fixing block (19) is vertically mounted inside the second slot (17). A first sliding slot (20) is vertically opened on one side of the second fixing block (19) close to the third slot (18). A first electric slider (21) is slidably mounted inside the first sliding slot (20). One side of the first electric slider (21) far from the first sliding slot (20) is movably connected to a third connecting rod (24). One end of the third connecting rod (24) far from the first electric slider (21) is connected to a scraper (25).

2. The traffic patrol drone capable of real-time positioning based on the Internet of Things according to claim 1, wherein The buffer mechanism includes a first connecting rod (3), a spring (5) and a second connecting rod (6). First connecting rods (3) are mounted at the bottom ends of the support arms of the UAV body (1). A first slot (4) is vertically opened at the bottom end of the first connecting rod (3). A second connecting rod (6) is movably inserted and mounted inside the first slot (4). A spring (5) is connected between the top end of the second connecting rod (6) and the top end of the inner wall of the first slot (4). The bottom end of the second connecting rod (6) is connected to the top end of the mounting plate (2).

3. The traffic patrol drone capable of real-time positioning based on the Internet of Things according to claim 1, wherein, Two electric telescopic rods (8) are embedded and mounted on both sides of the mounting plate (2). The telescopic ends of the electric telescopic rods (8) are all far from the mounting plate (2). The telescopic ends of the electric telescopic rods (8) are connected to the air bags (7).

4. The traffic patrol drone capable of real-time positioning based on the Internet of Things according to claim 1, characterized in that, One end of the first electric slider (21) far from the first sliding slot (20) is mounted with a fourth rotating motor (22). The output end of the fourth rotating motor (22) is far from the first electric slider (21). The output end of the fourth rotating motor (22) is mounted with a fifth rotating motor (23). The output end of the fifth rotating motor (23) faces the mounting plate (2). The output end of the fifth rotating motor (23) is connected to one end of the third connecting rod (24) far from the scraper (25).

5. The traffic patrol drone capable of real-time positioning based on the Internet of Things according to claim 1, characterized in that, The stability mechanism includes a first fan (13) and a second fan (14). At the top of the mounting plate (2), the first fans (13) are movably installed on both sides of the UAV body (1), and the second fan (14) is movably installed at the top of the mounting plate (2) at the end of the UAV body (1) away from the camera.

6. The traffic patrol drone capable of real-time positioning based on the Internet of Things according to claim 1, wherein At the top of the mounting plate (2), second rotating motors (15) are embedded at the bottom of the first fans (13), and the output ends of the second rotating motors (15) are respectively connected to the bottom ends of the first fans (13). At the top of the mounting plate (2), a third rotating motor (16) is embedded at the bottom of the second fan (14), and the output end of the third rotating motor (16) is connected to the bottom end of the second fan (14).

7. The traffic patrol drone capable of real-time positioning based on the Internet of Things according to claim 1, wherein, On both sides of the scraping plate (25), triangular blocks (26) are vertically installed along the end wall direction. The length direction of the scraping plate (25) is parallel to the length direction of the third slot (18), and the length of the scraping plate (25) is less than the length of the third slot (18).

Images