A pesticide spraying machine with a dispensing function

Abstract

The utility model discloses a kind of pesticide sprayer with dispensing function, including external frame, the external frame is provided with pesticide mechanism, the pesticide mechanism includes dispensing bucket and water pump, dispensing bucket is installed on external frame, water pump is connected at dispensing bucket bottom end, the external frame is fixed with support frame, the water pump output end is connected with output pipe, the output pipe is fixed on support frame, the output pipe top end is connected with connecting pipe, the connecting pipe is provided with multiple groups and top end is equipped with spray head, quick coupling mechanism is arranged between the spray head and connecting pipe, the quick coupling mechanism includes connecting sleeve and clamping pipe, connecting sleeve is fixed at connecting pipe top end, clamping pipe is fixed at spray head one end, rotating sleeve is rotatably connected on the connecting sleeve, only need to insert clamping pipe into rotating sleeve and connecting sleeve, positioning by positioning slot and positioning block, then anticlockwise rotating rotating sleeve drives clamping pipe to rotate, make clamping plate insert into insertion hole, and installation can be completed.

Description

Technical Field

[0001] This utility model relates to the field of agricultural technology, and more specifically, to a sprayer with a pesticide dispensing function. Background Technology

[0002] In agriculture, efficient and precise plant protection measures have a decisive impact on crop yield and quality. As a core tool for plant protection, sprayers with spraying capabilities directly affect operational efficiency and control effectiveness through their ease of use and adaptability. Currently, sprayers on the market face significant limitations in practical applications: different types of pesticides, fertilizers, or growth regulators often require different specifications and types of nozzles to achieve optimal atomization and coverage.

[0003] However, the nozzle design of traditional sprayers generally lacks flexibility. Operators need to frequently change nozzles for different crops, different pesticides, and different usage environments. Most sprayer nozzles in existing technologies use traditional methods such as threaded connections or snap-fit ​​fixings. These connection methods usually require the use of special tools for disassembly and assembly, which not only increases labor intensity but also reduces work efficiency. The problem of nozzle replacement is particularly prominent in large-scale planting areas and during the time-sensitive pest control season. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] In view of the problems existing in the prior art, this utility model provides a sprayer with a dispensing function to solve the technical problems mentioned in the background art.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, this utility model provides the following technical solution: a sprayer with a dispensing function, comprising an external frame, on which a spraying mechanism is provided. The spraying mechanism includes a dispensing tank and a water pump. The dispensing tank is mounted on the external frame, and the water pump is connected to the bottom of the dispensing tank. A support frame is fixedly provided on the external frame. An output pipe is connected to the output end of the water pump. The output pipe is fixed on the support frame. A connecting pipe is connected to the top end of the output pipe. Multiple sets of connecting pipes are provided, each with a nozzle at its top. A quick-connect mechanism is provided between the nozzle and the connecting pipe. The quick-connect mechanism includes a connecting sleeve and a clamping pipe. The connecting sleeve is fixed to the top end of the connecting pipe, and the clamping pipe is fixed to one end of the nozzle. A rotating sleeve is rotatably connected to the connecting sleeve. A clamping block is fixed inside the connecting sleeve. Multiple sets of clamping blocks are provided, each with an insertion hole on its outer wall. An installation block is fixed to the outer wall of the clamping pipe. Multiple sets of installation blocks are provided, each with a clamping plate fixed to its outer wall.

[0008] The present invention is further configured such that all of the multiple sets of card plates are arc-shaped and inserted into the insertion holes. The arc-shaped design provides a larger contact area and a more uniform stress distribution, allowing the card plates to slide smoothly into the insertion holes without jamming. At the same time, it enhances the firmness and torsional resistance of the connection, preventing the nozzle from loosening or falling off due to vibration or external force during use, and extending the service life and reliability of the quick-connect mechanism.

[0009] The present invention is further provided that the connecting sleeve is provided with a sealing gasket. The sealing gasket creates an efficient liquid sealing barrier, effectively preventing pesticides from leaking from the connection under high pressure, avoiding pesticide waste and environmental pollution, while reducing the risk of operators coming into contact with pesticides and improving the safety of equipment use. The design of the sealing gasket can also compensate for manufacturing tolerances and wear between components, ensuring that a good sealing effect is maintained even after long-term use.

[0010] The present invention is further configured such that a positioning block is fixedly provided on the inner wall of the rotating sleeve, and multiple sets of positioning blocks are provided; an insert sleeve is fixedly provided on the outer wall of the clamping tube, and a positioning groove is provided on the outer wall of the insert sleeve, and multiple sets of positioning grooves are provided and respectively inserted into multiple sets of positioning blocks. This positioning system establishes a precise rotation reference point and a fixed angle position, ensuring that the clamping plate can be accurately aligned with the insertion hole for insertion, preventing assembly misalignment. At the same time, the design of multiple sets of positioning blocks and positioning grooves disperses the stress at the connection point, enhances the structural strength, and improves the stability and durability of the quick-connect mechanism during use.

[0011] The present invention is further configured such that a push spring is fixedly provided on the top surface of the insert sleeve, and the push spring constitutes an automatic separation mechanism. When the rotating sleeve rotates and the card plate is disengaged from the insertion hole, the push spring releases the stored elastic potential energy and automatically pushes the insert sleeve and the connected nozzle away from the connecting sleeve, thereby achieving rapid separation without the need for additional pulling action. This simplifies the operation steps, improves the efficiency of nozzle replacement, and is particularly suitable for scenarios where different nozzles need to be switched quickly during continuous operation.

[0012] The present invention is further configured such that an abutment ring is fixedly provided at the top of the push spring, and a pressure ring is fixedly provided on the inner wall of the rotating sleeve. This combination forms a pre-tightening force control system. When the clamping tube is inserted into the connecting sleeve, the abutment ring and the pressure ring contact to generate appropriate axial pressure, compress the push spring and provide a stable pre-tightening force, ensuring a firm connection and that the sealing gasket is subjected to uniform pressure to form a reliable seal. At the same time, the pre-tightening force design reduces the gap between components, reduces the risk of vibration and loosening during use, and extends the service life of the entire quick-connect system.

[0013] The present invention is further configured such that a limiting mechanism is provided at the top of the connecting sleeve, the limiting mechanism including a limiting sleeve and a limiting groove. The limiting sleeve is fixed to the bottom surface of the connecting sleeve and rotatably connected to the rotating sleeve. Multiple sets of limiting grooves are distributed on the outer wall of the rotating sleeve. The inner wall of the limiting sleeve is provided with sliding holes, and multiple sets of sliding holes are provided. Each set of sliding holes has a limiting block slidably disposed therein. Each set of limiting blocks is connected to the sliding holes with a compression spring. This limiting mechanism creates a safe and reliable locking system. The compression spring pushes the limiting block into the limiting groove to form a physical lock, preventing the rotating sleeve from rotating and loosening due to vibration during use. At the same time, the design of multiple sets of limiting blocks and limiting grooves provides multi-point locking, enhances the locking strength and anti-torsion ability, and ensures that the nozzle can still be stably connected under high-pressure working conditions.

[0014] The present invention is further configured such that the bottom ends of the multiple sets of limiting blocks and the limiting grooves are all arc-shaped and abut against each other. The arc-shaped design realizes a smooth sliding and transition experience. When the rotating sleeve rotates, the arc-shaped limiting blocks can slide smoothly along the limiting grooves without jamming, reducing operating resistance and component wear. At the same time, it provides a gradual disengagement contact, avoiding the impact that may be caused by sudden disengagement, making the entire rotation operation smoother and more fluid, and improving the reliability and user experience of long-term use.

[0015] (III) Beneficial Effects

[0016] Compared with the prior art, this utility model provides a sprayer with a dispensing function, which has the following beneficial effects:

[0017] 1. The quick-connect mechanism consists of a connecting sleeve and a clamping tube. Together with a rotating sleeve, a clamping block, and an installation block, it enables a quick connection between the nozzle and the connecting pipe. In use, simply insert the clamping tube into the rotating sleeve and the connecting sleeve, position it using the positioning groove and the positioning block, and then rotate the rotating sleeve counterclockwise to rotate the clamping tube, allowing the clamping plate to be inserted into the insertion hole to complete the installation. This design not only eliminates the need for special tools and complex operating steps required by traditional threaded connections or snap-fit ​​fixings, but also greatly improves the efficiency of agricultural and horticultural operations. It allows operators to quickly switch nozzles according to different crops, pesticides, and environmental needs, meeting the precision and efficiency requirements of modern plant protection.

[0018] 2. The arc-shaped design of the clamping plate and the insertion hole forms a precise fit, enhancing the connection strength; the sealing gasket effectively prevents pesticide leakage, protecting the environment and operator safety; the combination of the push spring and the abutment ring provides appropriate axial preload, ensuring the connection remains stable even under vibration; the limit block and compression spring system in the limit mechanism automatically lock the position of the rotating sleeve to prevent accidental loosening. These designs work together to solve the problems of jamming and leakage caused by component wear or pesticide corrosion after long-term use of traditional connection methods, extending the service life of the equipment, reducing maintenance costs, and reducing the risk of environmental pollution. It is particularly suitable for professional plant protection teams to use in continuous operation or multi-area rotation spraying.

[0019] 3. When the nozzle needs to be replaced, simply rotate the rotating sleeve clockwise. The limiting block will slide along the sliding hole and compress the compression spring. At the same time, the rotating sleeve drives the clamping tube to rotate, causing the clamping plate to disengage from the insertion hole. The push spring resets and pushes the insertion sleeve away from the rotating sleeve, achieving quick disassembly of the nozzle. The entire process requires no tools and can be completed with one hand, greatly reducing the labor intensity of the operator. The arc-shaped limiting block and limiting groove design provides a smooth rotation experience and reduces operating resistance. Even in the presence of pesticide residues, it can maintain good operability. This convenient disassembly and assembly method not only improves the continuity of operations and saves valuable prevention and control time, but also reduces the risk of component damage caused by improper operation, meeting the comprehensive requirements of modern agriculture for high efficiency, safety and environmental protection. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of a sprayer with a dispensing function according to the present invention;

[0021] Figure 2 This is a schematic diagram of the disassembly structure of the nozzle in this utility model;

[0022] Figure 3 This is a cross-sectional view of the quick-connect mechanism in this utility model;

[0023] Figure 4 This is a cross-sectional view of the connecting sleeve and the rotating sleeve in this utility model.

[0024] Figure 5 This is a cross-sectional view of the limiting sleeve in this utility model.

[0025] In the diagram: 1. External frame; 2. Dosing tank; 3. Water pump; 4. Support frame; 5. Output pipe; 6. Connecting pipe; 7. Nozzle; 8. Connecting sleeve; 9. Clamping pipe; 10. Rotating sleeve; 11. Clamping block; 12. Insertion hole; 13. Mounting block; 14. Clamping plate; 15. Sealing gasket; 16. Positioning block; 17. Insertion sleeve; 18. Positioning groove; 19. Push spring; 20. Abutment ring; 21. Pressure ring; 22. Limiting sleeve; 23. Limiting groove; 24. Sliding hole; 25. Limiting block; 26. Compression spring. Detailed Implementation

[0026] It should be noted that, where there is no conflict, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0028] In this utility model, unless otherwise stated, the orientations used, such as "up" and "down", usually refer to the direction shown in the accompanying drawings, or to the vertical, perpendicular, or gravitational direction; similarly, for ease of understanding and description, "left" and "right" usually refer to the left and right shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not used to limit this utility model.

[0029] Please see Figures 1-5 A sprayer with a dispensing function includes an external frame 1, on which a spraying mechanism is mounted. The spraying mechanism includes a dispensing tank 2 and a water pump 3. The dispensing tank 2 is mounted on the external frame 1, and the water pump 3 is connected to the bottom of the dispensing tank 2. A support frame 4 is fixedly mounted on the external frame 1. An output pipe 5 is connected to the output end of the water pump 3. The output pipe 5 is fixed to the support frame 4. A connecting pipe 6 is connected to the top end of the output pipe 5. Multiple sets of connecting pipes 6 are provided, and each top end is provided with a nozzle 7. A quick-connect mechanism is provided between the nozzle 7 and the connecting pipe 6. The quick-connect mechanism includes a connecting sleeve 8 and a clamping pipe 9. The connecting sleeve 8 is fixed to the top end of the connecting pipe 6, and the clamping pipe 9 is fixed to one end of the nozzle 7. A rotating sleeve 10 is rotatably connected to the connecting sleeve 8. A clamping block 11 is fixedly mounted inside the connecting sleeve 8. Multiple sets of clamping blocks 11 are provided, and each outer wall is provided with an insertion hole 12. An installation block 13 is fixedly mounted on the outer wall of the clamping pipe 9. Multiple sets of installation blocks 13 are provided, and each outer wall is fixedly provided with a clamping plate 14.

[0030] Multiple sets of clamping plates 14 are all designed to be arc-shaped and inserted into the sockets 12. The arc-shaped clamping plates 14 provide a progressive insertion force. When the clamping plates 14 are inserted into the sockets 12, the arc design gradually increases the contact area and the stress distribution is more uniform. At the same time, the arc structure increases the friction and pull-out resistance after clamping, forming a stable mechanical lock and preventing the connection from loosening due to vibration or pressure fluctuations during use.

[0031] The connecting sleeve 8 is equipped with a sealing gasket 15. After the connection is completed, the sealing gasket 15 is compressed and deformed to fill the tiny gap between the connecting sleeve 8 and the clamping pipe 9, forming a continuous liquid barrier layer to prevent high-pressure pesticides from leaking from the interface. At the same time, the elastic properties of the sealing gasket 15 can compensate for manufacturing tolerances and wear during use, maintaining a long-term stable sealing effect.

[0032] The inner wall of the rotating sleeve 10 is fixedly provided with a positioning block 16, and multiple sets of positioning blocks 16 are provided. The outer wall of the snap-fit ​​tube 9 is fixedly provided with a plug sleeve 17, and the outer wall of the plug sleeve 17 is provided with a positioning groove 18. Multiple sets of positioning grooves 18 are provided and are respectively inserted into multiple sets of positioning blocks 16. Multiple sets of positioning blocks 16 and positioning grooves 18 form an angular positioning system to ensure that the snap-fit ​​tube 9 can be aligned with the plug hole 12 at the correct angle when inserted. At the same time, the multiple sets of designs disperse the torque load and improve the connection strength. This cooperation method also prevents the snap-fit ​​tube 9 from axially shaking during the rotation locking process.

[0033] A push spring 19 is fixedly provided on the top surface of the insert 17. When the snap tube 9 is inserted into the connecting sleeve 8, the push spring 19 is compressed and stores elastic potential energy. When disassembly is required, after rotating to release the locking between the snap plate 14 and the insertion hole 12, the push spring 19 releases the stored energy and automatically pushes the insert 17 and the connected snap tube 9 out of the connecting sleeve 8 without additional pulling force, thus realizing a semi-automatic disassembly auxiliary function.

[0034] The push spring 19 is fixedly provided with an abutment ring 20 at its top end, and the rotating sleeve 10 is fixedly provided with a pressure ring 21 on its inner wall. When the retaining tube 9 is fully inserted, the abutment ring 20 and the pressure ring 21 contact each other to form an axial force point, which applies a predetermined compression amount to the push spring 19 and generates a stable pre-tightening force to act on the connection, ensuring that the sealing gasket 15 is subjected to uniform pressure to form a reliable seal. At the same time, the pre-tightening force reduces the gap between components and improves the overall connection rigidity.

[0035] A limiting mechanism is provided at the top of the connecting sleeve 8. The limiting mechanism includes a limiting sleeve 22 and a limiting groove 23. The limiting sleeve 22 is fixed to the bottom surface of the connecting sleeve 8 and is rotatably connected to the rotating sleeve 10. Multiple sets of limiting grooves 23 are provided on the outer wall of the rotating sleeve 10. A sliding hole 24 is provided on the inner wall of the limiting sleeve 22. Multiple sets of sliding holes 24 are provided. A limiting block 25 is slidably provided in each set of sliding holes 24. A compression spring 26 is connected between each set of limiting blocks 25 and the sliding hole 24. The compression spring 26 continuously pushes the limiting block 25 to abut against the limiting groove 23, forming a physical block to prevent the rotating sleeve 10 from rotating on its own. When the rotating sleeve 10 is actively rotated, the limiting block 25 overcomes the elastic force of the compression spring 26 and retracts into the sliding hole 24, allowing rotation. After rotating to the correct position, the limiting block 25 pops out again under the action of the compression spring 26 and enters a new limiting groove 23, realizing the automatic positioning and locking function.

[0036] The bottom ends of multiple sets of limiting blocks 25 and limiting grooves 23 are all set to be arc-shaped and abut against each other. When the rotating sleeve 10 rotates, the arc surface of the bottom end of the limiting block 25 slides smoothly along the arc inner wall of the limiting groove 23, which reduces contact stress and frictional resistance, making the rotation operation smoother. At the same time, the arc contact also avoids the wear and jamming problems that may be caused by the sharp corner contact, and extends the service life of the component.

[0037] In this embodiment, during use, the clamping tube 9 is inserted into the rotating sleeve 10 and the connecting sleeve 8, and is positioned and inserted into the positioning block 16 through multiple sets of positioning grooves 18. At the same time, the abutting ring 20 abuts against the bottom surface of the pressure ring 21 and squeezes the push spring 19. Rotating the rotating sleeve 10 counterclockwise drives the clamping tube 9 to rotate and causes multiple sets of clamping plates 14 to be inserted into the insertion hole 12. Multiple sets of pressure springs 26 push the limiting block 25 to abut against the limiting groove 23 to limit the rotating sleeve 10, thus completing the quick installation of the nozzle 7. The water pump 3 is started to extract the pesticide in the mixing tank 2 and transport it to multiple sets of connecting pipes 6 through the delivery pipe. Then, the pesticide is sprayed through multiple sets of nozzles 7.

[0038] More specifically, when it is necessary to disassemble the nozzle 7, rotate the rotating sleeve 10 clockwise. This pushes the multiple sets of limiting blocks 25 along the sliding hole 24 through the multiple sets of limiting grooves 23 and compresses the multiple sets of compression springs 26. Continuously rotating the rotating sleeve 10 causes the multiple sets of limiting blocks 25 to move within the multiple sets of limiting grooves 23. The rotating sleeve 10 drives the locking tube 9 to rotate. The rotation of the locking tube 9 causes the multiple sets of locking plates 14 to disengage from the insertion hole 12. The push spring 19 resets and pushes the insertion sleeve 17, causing the insertion sleeve 17 to disengage from the rotating sleeve 10, thus completing the quick disassembly of the nozzle 7.

[0039] In summary, when using or operating the entire equipment: During use, the clamping tube 9 is inserted into the rotating sleeve 10 and connecting sleeve 8, and positioned and inserted into the positioning block 16 via multiple sets of positioning grooves 18. Simultaneously, the abutting ring 20 abuts against the bottom surface of the pressure ring 21 and squeezes the push spring 19. Rotating the rotating sleeve 10 counterclockwise causes the clamping tube 9 to rotate, and multiple sets of clamping plates 14 are inserted into the insertion hole 12. Multiple sets of pressure springs 26 push the limiting block 25 to abut against the limiting groove 23, limiting the rotation sleeve 10 and completing the rapid installation of the nozzle 7. The water pump 3 is then started to extract pesticide from the mixing tank 2 and transport it through the delivery pipe to multiple sets of connecting pipes 6. Subsequently, the pesticide is sprayed through multiple sets of nozzles 7.

[0040] However, when it is necessary to disassemble the nozzle 7, rotate the rotating sleeve 10 clockwise. Through multiple sets of limiting grooves 23, push multiple sets of limiting blocks 25 to slide along the sliding hole 24 and compress multiple sets of compression springs 26. Continue to rotate the rotating sleeve 10 so that the multiple sets of limiting blocks 25 move within the multiple sets of limiting grooves 23. The rotating sleeve 10 drives the locking tube 9 to rotate. The rotation of the locking tube 9 causes multiple sets of locking plates 14 to disengage from the insertion hole 12. Through the push spring 19, the insertion sleeve 17 is pushed back to disengage from the rotating sleeve 10, thus completing the quick disassembly of the nozzle 7.

[0041] Of all the solutions mentioned above, those involving the connection between two components can be selected according to the actual situation, such as welding, bolt and nut connection, bolt or screw connection, or other well-known connection methods. They will not be elaborated here. For all the fixed connections mentioned above, welding is the preferred option.

[0042] In all the solutions mentioned above, those involving the operation of electrical components, unless otherwise specified, are controlled by a controller. Since the devices matched with the controllers are common devices, their control principles and circuit connections are existing, well-known, and mature technologies, and their specific circuit structures will not be described in detail here.

[0043] Of all the solutions mentioned above, those involving motors can be combined with reducers if necessary. The connection structure and working principle between the motor and the reducer are existing known technologies and will not be addressed in this utility model.

[0044] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A sprayer with a dispensing function, comprising an external frame (1), characterized in that: The external frame (1) is equipped with a spraying mechanism, which includes a mixing tank (2) and a water pump (3). The mixing tank (2) is installed on the external frame (1), and the water pump (3) is connected to the bottom of the mixing tank (2). A support frame (4) is fixedly installed on the external frame (1). An output pipe (5) is connected to the output end of the water pump (3). The output pipe (5) is fixed on the support frame (4). A connecting pipe (6) is connected to the top end of the output pipe (5). The connecting pipe (6) is provided with multiple sets, each with a nozzle (7) at its top. The nozzle (7) is connected to the connecting pipe (6). 6) A quick-connect mechanism is provided between them. The quick-connect mechanism includes a connecting sleeve (8) and a clamping tube (9). The connecting sleeve (8) is fixed to the top of the connecting tube (6), and the clamping tube (9) is fixed to one end of the nozzle (7). A rotating sleeve (10) is rotatably connected to the connecting sleeve (8). A clamping block (11) is fixed inside the connecting sleeve (8). The clamping block (11) is provided in multiple sets and each has an insertion hole (12) on its outer wall. An installation block (13) is fixed on the outer wall of the clamping tube (9). The installation block (13) is provided in multiple sets and each has a clamping plate (14) fixed on its outer wall.

2. A sprayer with a dispensing function according to claim 1, characterized in that: All of the aforementioned card plates (14) are configured to be arc-shaped and inserted into the sockets (12).

3. A sprayer with a dispensing function according to claim 2, characterized in that: The connecting sleeve (8) is provided with a sealing gasket (15).

4. A sprayer with a dispensing function according to claim 3, characterized in that: The inner wall of the rotating sleeve (10) is fixedly provided with a positioning block (16), and there are multiple sets of positioning blocks (16). The outer wall of the snap tube (9) is fixedly provided with a plug sleeve (17), and the outer wall of the plug sleeve (17) is provided with a positioning groove (18). There are multiple sets of positioning grooves (18) and they are respectively plugged into multiple sets of positioning blocks (16).

5. A sprayer with a dispensing function according to claim 4, characterized in that: A push spring (19) is fixedly provided on the top surface of the sleeve (17).

6. A sprayer with a dispensing function according to claim 5, characterized in that: The push spring (19) is fixedly provided with an abutment ring (20) at its top end, and the rotating sleeve (10) is fixedly provided with a pressure ring (21) on its inner wall.

7. A sprayer with a dispensing function according to claim 6, characterized in that: The top of the connecting sleeve (8) is provided with a limiting mechanism, which includes a limiting sleeve (22) and a limiting groove (23). The limiting sleeve (22) is fixed to the bottom surface of the connecting sleeve (8) and rotatably connected to the rotating sleeve (10). The limiting groove (23) is provided in multiple sets distributed on the outer wall of the rotating sleeve (10). The inner wall of the limiting sleeve (22) is provided with a sliding hole (24). The sliding hole (24) is provided in multiple sets. A limiting block (25) is slidably provided in each of the multiple sets of sliding holes (24). A compression spring (26) is connected between each of the multiple sets of limiting blocks (25) and the sliding hole (24).

8. A sprayer with a dispensing function according to claim 7, characterized in that: The bottom ends of the multiple sets of limiting blocks (25) and the limiting grooves (23) are all set to be arc-shaped and abut against each other.

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