Intelligent spraying tool for anticorrosive paint of foundation bolt

Abstract

The utility model belongs to the technical field of electric power equipment maintenance tools, and particularly relates to an intelligent spraying tool for anticorrosive paint of a foundation bolt, which comprises a sleeve, a spraying head, a spraying head and a spraying head, the annular cavity is formed in the side wall of the sleeve, arc-shaped partition plates are arranged in the annular cavity at equal intervals, a coating channel is formed between every two adjacent partition plates, and a plurality of rows of spraying holes are formed in the positions, corresponding to the coating channels, of the inner wall face of the coating cavity; the sealing cover is arranged at the top end of the sleeve; the gun body is connected with the sealing cover, and a feeding main pipe with the tail end capable of being connected with a pressure pump pipeline is arranged on the gun body; the bottom ends of the feeding branch pipes are connected with the sealing cover, the feeding branch pipes are arranged corresponding to the coating channels respectively, and the top ends of the feeding branch pipes are connected with the feeding main pipe. The device has the advantages that the anticorrosion quality and the coating efficiency of the foundation bolt are improved, the labor intensity and the maintenance cost are effectively reduced, and the reliability and the stability of the operation of substation equipment are practically enhanced.

Description

Technical Field

[0001] This utility model relates to the technical field of power equipment maintenance tools; specifically, this utility model relates to an intelligent spraying tool for anti-corrosion coating of anchor bolts. Background Technology

[0002] In the daily operation and maintenance of substations, the corrosion protection of foundation anchor bolts plays a crucial role in the stability and safety of the equipment. Traditionally, applying anti-corrosion coating to anchor bolts relies mainly on manual labor using brushes or simple tools. However, this traditional method has several significant drawbacks. Manual application makes it difficult to ensure the anti-corrosion coating is evenly distributed across all parts of the bolt, especially in areas deep within the threads and at the bottom. Insufficient coating or inconsistent thickness is common, severely weakening the bolt's anti-corrosion performance and significantly increasing the risk of bolt loosening and damage due to rust, thus posing a serious threat to the normal operation of substation equipment. Furthermore, traditional manual operation is extremely inefficient, requiring a large investment of manpower and time to handle a large number of anchor bolts. When encountering bolts in special locations, such as in confined spaces or at high altitudes, the difficulty of operation increases dramatically, often requiring additional climbing equipment or special tools. This not only significantly increases the difficulty of the work but also significantly increases the operational risks, bringing numerous inconveniences and challenges to power equipment maintenance. Utility Model Content

[0003] In view of this, the present invention provides an intelligent spraying tool for anti-corrosion coating of anchor bolts, which solves the problems of uneven application, low efficiency and inconvenient operation in traditional anti-corrosion coating methods, and fully improves the anti-corrosion quality and coating efficiency of anchor bolts, effectively reduces labor intensity and maintenance costs, and effectively enhances the reliability and stability of substation equipment operation.

[0004] To achieve the aforementioned objectives, this utility model provides an intelligent spraying tool for anti-corrosion coating on anchor bolts, comprising:

[0005] The sleeve has a central cavity that can be fitted onto the outside of the anchor bolt from top to bottom;

[0006] An annular cavity is provided inside the side wall of the sleeve. Arc-shaped partitions are equidistantly arranged inside the annular cavity, and a paint channel is formed between two adjacent partitions. The inner wall surface of the encapsulated cavity is provided with multiple rows of spray holes corresponding to each paint channel.

[0007] A cap is provided at the top of the sleeve to seal the top of the annular cavity;

[0008] The gun body is connected to the cover, and the gun body is provided with a main feed pipe whose tail end can be connected to a pressure pump pipe;

[0009] The feed pipe is connected to the cap at its bottom end, and one is provided for each paint channel. The top end of the feed pipe is connected to the feed main pipe. The feed pipe is used to transport paint from the feed main pipe to the paint channel.

[0010] In the aforementioned intelligent spraying tool for anti-corrosion coating of anchor bolts, optionally, the top of the partition is a pointed tip, the cover includes a first circular part, a second circular part, a conical part and a third circular part distributed from top to bottom, the bottom end of the feeding pipe is connected to the first circular part, the outer surface of the first circular part is connected to the top end of the outer wall of the annular cavity, the outer diameter of the second circular part is smaller than the outer diameter of the third circular part, the outer diameter of the third circular part is adapted to the inner diameter of the partition, and the bottom height of the third circular part is smaller than the bottom height of the tip of the partition.

[0011] In the aforementioned intelligent spraying tool for anti-corrosion coating of anchor bolts, optionally, the inner wall of the annular cavity is divided into a first annular plate and a plurality of second annular plates distributed sequentially from the top of the first annular plate upwards. The first annular plate and the second annular plates are of the same size. The spray holes are evenly distributed on the first annular plate and the plurality of second annular plates. The first annular plate is fixedly connected to the inner bottom wall of the annular cavity. The second annular plates located at the top of the first annular plate and the two adjacent second annular plates are rotatably fitted together. The bottom end of the third circular part contacts the top of the uppermost second annular plate. The width of the partition is greater than the width of the coating channel. The sleeve is provided with a control component that can control the rotation of each second annular plate so that the spray holes are blocked by the partition.

[0012] In the aforementioned intelligent spraying tool for anti-corrosion coating of anchor bolts, optionally, the control component includes a guide rod fixedly disposed on the inner surface of the second partition, a lifting rod capable of moving up and down within the covering cavity, a spiral groove disposed on the surface of the lifting rod for driving the guide rod to perform circular motion, and an upper straight groove and a lower straight groove respectively disposed at the upper and lower ends of the spiral groove for the guide rod to enter and exit the spiral groove.

[0013] In the aforementioned intelligent spraying tool for anti-corrosion coating of anchor bolts, optionally, the center of the cover is provided with a through hole for the lifting rod to pass through, the top end of the lifting rod passes through the through hole and is fixedly connected to the front end of the gun body, the inner wall of the through hole is provided with a strip slider that slides in the upper straight groove, and when the lifting rod is in the lowest position, all guide rods are located in the upper straight groove.

[0014] In the aforementioned intelligent spraying tool for anti-corrosion coating of anchor bolts, optionally, the feeding pipe is a flexible hose, and the feeding pipe is located outside the lifting rod.

[0015] In the aforementioned intelligent spraying tool for anti-corrosion coating of anchor bolts, optionally, the inner surface of the partition plate is provided with a groove, and a baffle group capable of displacement along the inner circumferential direction of the groove is provided between two adjacent second ring plates. The two adjacent baffle groups are respectively located in two adjacent grooves. The baffle group includes a long baffle and a short baffle. The top end of the long baffle is fixed to the surface of the upper second ring plate among the two adjacent second ring plates, and the short baffle is fixed to the surface of the lower second ring plate among the two adjacent second ring plates. The bottom end of the long baffle extends to the surface of the lower second ring plate and contacts the short baffle.

[0016] In the aforementioned intelligent spraying tool for anti-corrosion coating of anchor bolts, optionally, the top of the first circular part is rotatably engaged with the outer inner wall of the annular cavity, and when the spray hole is aligned with the corresponding coating channel, the short baffle contacts one side of the inner wall of the groove; when the spray hole is blocked by the partition, the long baffle contacts the other side of the inner wall of the groove.

[0017] This utility model relates to an intelligent spraying tool for anti-corrosion coating on anchor bolts. By using a sleeve, the anchor bolts are directly fitted from top to bottom, covering them within the covering cavity. The tool then uses side spray holes to spray the coating onto the anchor bolts in a 360-degree circumferential manner. This not only improves spraying efficiency and reduces operational difficulty, but also makes the anti-corrosion coating more evenly applied, effectively reducing labor intensity and maintenance costs. Attached Figure Description

[0018] The disclosure of this utility model will become more apparent with reference to the accompanying drawings. It should be understood that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this utility model. In the drawings:

[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0020] Figure 2 This utility model Figure 1 A schematic diagram of the middle sleeve and the first annular plate after being cut open;

[0021] Figure 3 This utility model Figure 2 Enlarged view of point A in the middle;

[0022] Figure 4 This utility model Figure 2 Enlarged view at point B in the middle;

[0023] Figure 5 This utility model Figure 1 A schematic diagram of the sleeve, the first annular plate, and the partition plate in the middle;

[0024] Figure 6 This is a cross-sectional view of the sleeve, the first annular plate, and the cap of this utility model;

[0025] Figure 7 This is a schematic diagram of the first ring plate of this utility model;

[0026] Figure 8 This is a schematic diagram of the lifting rod of this utility model.

[0027] Reference numerals: 1-Sleeve; 2-Covering cavity; 3-Annular cavity; 3.1-First annular plate; 3.2-Second annular plate; 4-Baffle; 5-Paint channel; 6-Spray hole; 7-Cap; 7.1-First circular part; 7.2-Second circular part; 7.3-Conical part; 7.4-Third circular part; 8-Gun body; 9-Main feed pipe; 10-Feed branch pipe; 11-Guide rod; 12-Lifting rod; 13-Spiral groove; 14-Upper straight groove; 15-Lower straight groove; 16-Through hole; 17-Strip slider; 18-Groove; 19-Baffle assembly; 19.1-Long baffle; 19.2-Short baffle. Detailed Implementation

[0028] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0029] like Figures 1 to 8 As shown, this utility model provides an intelligent spraying tool for anti-corrosion coating on anchor bolts, comprising:

[0030] The sleeve 1 has a centrally located covering cavity 2 that can be fitted onto the outside of the anchor bolt from top to bottom. When spraying anti-corrosion coating onto the anchor bolt, the sleeve 1 is first fitted onto the anchor bolt from top to bottom, covering the anchor bolt in a relatively enclosed area. This ensures that the anti-corrosion coating can be sprayed directly onto the anchor bolt more efficiently during the spraying operation, without being affected by ambient wind. At the same time, it can prevent dust from being stirred up in the vicinity of the anchor bolt during the anti-corrosion coating process and then adhering to the anchor bolt along with the anti-corrosion coating, thus ensuring the spraying effect.

[0031] An annular cavity 3 is located inside the side wall of the sleeve 1. Arc-shaped partitions 4 are equidistantly arranged inside the annular cavity 3, and a paint channel 5 is formed between two adjacent partitions 4. The inner wall surface of the covering cavity 2 is provided with multiple rows of spray holes 6 corresponding to each paint channel 5. The multiple rows of spray holes 6 surround the anchor bolts in the circumferential direction, so that the anti-corrosion coating can be sprayed on all parts of the anchor bolts in the circumferential direction during the spraying process. The limitation of the narrow space on the side of the anchor bolts near the equipment can avoid the disadvantage of conventional spray guns not being able to directly face or brushes not being able to directly contact the surface of the anchor bolts in the narrow space, which would prevent the anti-corrosion coating from being sprayed in all directions.

[0032] The cap 7 is provided at the top of the sleeve 1 to seal the top of the annular cavity 3; the gun body 8 is connected to the cap 7 and has a main feed pipe 9 whose tail end can be connected to a pressure pump pipe; the feed branch pipe 10 is connected to the cap 7 at its bottom end and is provided for each paint channel 5. The top end of the feed branch pipe 10 is connected to the main feed pipe 9 and the feed branch pipe 10 is used to transport the paint from the main feed pipe 9 to the paint channel 5.

[0033] By operating the trigger on the spray gun, the main spray gun control pipe opens, allowing the anti-corrosion coating, pumped into the main feed pipe 9 by the pressure pump, to enter the annular cavity 3 through the feed branch pipe 10. Then, under pressure, it is sprayed from the nozzle 6 onto the anchor bolts. Simultaneously, during the spraying operation, rotating the sleeve 1 allows the nozzle 6 to rotate around the anchor bolts, enabling more uniform and all-around application of the anti-corrosion coating.

[0034] In this embodiment, the top of the partition 4 is a pointed tip, and the cover 7 includes a first circular portion 7.1, a second circular portion 7.2, a conical portion 7.3 and a third circular portion 7.4 distributed from top to bottom. The bottom end of the feed pipe 10 is connected to the first circular portion 7.1. The outer surface of the first circular portion 7.1 is connected to the top of the outer wall of the annular cavity 3. The outer diameter of the second circular portion 7.2 is smaller than the outer diameter of the third circular portion 7.4. The outer diameter of the third circular portion 7.4 is adapted to the inner diameter of the partition 4, and the bottom height of the third circular portion 7.4 is smaller than the bottom height of the tip of the partition 4.

[0035] The anti-corrosion coating in the feed pipe 10 first passes through the cap 7 and then enters the coating channel 5. By setting the conical part 7.3 and making the outer diameter of the second circular part 7.2 smaller than that of the third circular part 7.4, the distance between the second circular part 7.2 and the outer inner wall of the annular cavity 3 is larger, making this distance greater than the bottom diameter of the feed pipe 10. The anti-corrosion coating entering the cap 7 is guided by the conical part 7.3 and the tip of the baffle 4 and converges into the coating channel 5. At the same time, as the space through which the anti-corrosion coating passes continuously decreases, the anti-corrosion coating can be pressurized, improving its spraying effect.

[0036] Furthermore, the inner wall of the annular cavity 3 is divided into a first annular plate 3.1 and a plurality of second annular plates 3.2 distributed sequentially from the top of the first annular plate 3.1 upwards. The first annular plate 3.1 and the second annular plate 3.2 are the same size. The nozzles 6 are evenly distributed on the first annular plate 3.1 and the plurality of second annular plates 3.2. The first annular plate 3.1 is fixed to the inner bottom wall of the annular cavity 3. The second annular plates 3.2 located at the top of the first annular plate 3.1 and adjacent second annular plates 3.2 are rotatably fitted together. The bottom end of the third circular part 7.4 contacts the top of the uppermost second annular plate 3.2. The width of the partition plate 4 is greater than the width of the paint channel 5. The sleeve 1 is provided with a control component that can control the rotation of each second annular plate 3.2 so that the nozzles 6 are blocked by the partition plate 4.

[0037] In this embodiment, the second ring plate 3.2 can be rotated to control the spray holes 6 on its sidewalls to enter the area of ​​the partition plate 4 and be blocked by the partition plate 4, thus sealing the spray holes 6 on the second ring plate 3.2. Therefore, during the spraying operation, depending on the height of the anchor bolt being sprayed, the second ring plate 3.2 with a height greater than the top height of the anchor bolt can be rotated to seal the spray holes 6 on that part of the second ring plate 3.2, thereby ensuring that the anti-corrosion coating can be sprayed more fully and effectively onto the anchor bolt, improving the utilization rate of the anti-corrosion coating and reducing waste of the anti-corrosion coating.

[0038] Specifically, the control components include a guide rod 11 fixedly disposed on the inner surface of the second partition 4, a lifting rod 12 capable of moving up and down within the covering cavity 2, a spiral groove 13 disposed on the surface of the lifting rod 12 for driving the guide rod 11 to perform circular motion, and an upper straight groove 14 and a lower straight groove 15 respectively disposed at the upper and lower ends of the spiral groove 13 for the guide rod 11 to enter and exit the spiral groove 13.

[0039] By operating the lifting rod 12 to move downwards, the guide rod 11 enters the spiral groove 13 from the lower straight groove 15. As the guide rod 11 passes through the spiral groove 13, the spiral groove 13 causes the second ring plate 3.2 to rotate via the guide rod 11, thereby controlling the nozzle 6 to enter the area of ​​the partition 4 and be closed. After passing the spiral groove 13, the guide rod 11 enters the upper straight groove 14. The upper straight groove 14 keeps the second ring plate 3.2 stable via the guide rod 11, so that the nozzle 6 remains closed by the partition 4. Conversely, when the lifting rod 12 rises, the guide rod 11 located in the upper straight groove 14 will pass downwards through the spiral groove 13 and the lower straight groove 15 in sequence. Then, when the lifting rod 12 rises to the initial height, the second ring plate 3.2 returns to the initial position. At this time, the nozzle 6 is located within the paint channel 5 and is in an open state.

[0040] Furthermore, when spraying anti-corrosion coating on the anchor bolts, after the sleeve 1 is put on the anchor bolts, the lifting rod 12 is directly lowered to the top of the anchor bolts. At this time, the lifting rod 12 is lowered to the lowest position, and the spray holes 6 on the second ring plate 3.2 corresponding to the guide rod 11 that enters the upper straight groove 14 in the guide rod 11 with a height greater than that of the anchor bolts are all in a closed state.

[0041] Furthermore, the center of the cover 7 has a through hole 16 for the lifting rod 12 to pass through. The top end of the lifting rod 12 passes through the through hole 16 and is fixedly connected to the front end of the gun body 8. The inner wall of the through hole 16 is provided with a strip-shaped slider 17 that slides in the upper straight groove 14. When the lifting rod 12 is at its lowest position in the sleeve 1, all guide rods 11 are located in the upper straight groove 14. The strip-shaped slider 17 can block the upper straight groove 14, preventing the anti-corrosion coating from escaping from the upper straight groove 14 during the process of spraying anti-corrosion coating on the anchor bolts. At the same time, it also prevents external dust from entering the covering cavity 2 from the upper straight groove 14. In addition, the strip-shaped slider 17 can prevent the lifting rod 12 from rotating, thereby keeping the gun body 8 stable and preventing the feeding pipe 10 from being pulled.

[0042] The feed pipe 10 is a flexible hose, and it is located outside the lifting rod 12. During the process of pressing down the gun body 8, the hose bends itself to ensure that the anti-corrosion coating can stably enter the coating channel 5 from the feed main pipe 9.

[0043] The partition 4 has a groove 18 on its inner surface. A baffle group 19 is provided between two adjacent second ring plates 3.2, which can be displaced in the inner circumferential direction of the groove 18. The two adjacent baffle groups 19 are located in the two adjacent grooves 18 respectively. The baffle group 19 includes a long baffle 19.1 and a short baffle 19.2. The top end of the long baffle 19.1 is fixed to the surface of the upper second ring plate 3.2 of the two adjacent second ring plates 3.2. The short baffle 19.2 is fixed to the surface of the lower second ring plate 3.2 of the two adjacent second ring plates 3.2. The bottom end of the long baffle 19.1 extends to the surface of the lower second ring plate 3.2 and contacts the short baffle 19.2.

[0044] By setting the baffle assembly 19, in the initial state, the uppermost guide rod 11 enters the lower straight groove 15, and then the lifting rod 12 is directly rotated to apply a pushing force to the short baffle 19.2 using the long stop rod, so that all the second ring plates 3.2 can be restored to the initial state. At the same time, it can be controlled that the spray holes 6 on all the second ring plates 3.2 are located within the paint channel 5 in the initial state.

[0045] Furthermore, the first circular portion 7.1 rotates with the top of the outer inner wall of the annular cavity 3, and when the nozzle 6 is aligned with the corresponding paint channel 5, the short baffle 19.2 contacts one side of the inner wall of the groove 18. When the nozzle 6 is blocked by the partition 4, the long baffle 19.1 contacts the other side of the inner wall of the groove 18. With this configuration, in the initial state, directly rotating the gun body 8 causes the lifting rod 12 to rotate. At this time, by using the long baffle 19.1 to apply a pushing force to the short baffle 19.2, all the second ring plates 3.2 can be rotated to the state where the nozzle 6 is aligned with the paint channel 5.

[0046] The technical scope of this utility model is not limited to the contents of the above description. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this utility model, and all such modifications and variations should fall within the scope of this utility model.

Claims

1. An intelligent spraying tool for anti-corrosion coating on anchor bolts, characterized in that, include: The sleeve (1) has a covering cavity (2) in the center that can be fitted from top to bottom onto the outside of the anchor bolt. An annular cavity (3) is located inside the side wall of the sleeve (1). Arc-shaped partitions (4) are equidistantly arranged inside the annular cavity (3). A paint channel (5) is formed between two adjacent partitions (4). The inner wall surface of the covering cavity (2) is provided with multiple rows of spray holes (6) corresponding to each paint channel (5). The cap (7) is set at the top of the sleeve (1) to seal the top of the annular cavity (3); The gun body (8) is connected to the cover (7), and the gun body (8) is provided with a feed pipe (9) whose tail end can be connected to a pressure pump pipe. The feed pipe (10) is connected to the cap (7) at its bottom end and is provided for each paint channel (5). The top end of the feed pipe (10) is connected to the feed main pipe (9). The feed pipe (10) is used to transport the paint from the feed main pipe (9) to the paint channel (5).

2. The intelligent spraying tool for anti-corrosion coating of anchor bolts according to claim 1, characterized in that, The top of the partition (4) is a pointed tip. The cover (7) includes a first circular part (7.1), a second circular part (7.2), a conical part (7.3) and a third circular part (7.4) distributed from top to bottom. The bottom end of the feed pipe (10) is connected to the first circular part (7.1). The outer surface of the first circular part (7.1) is connected to the top of the outer wall of the annular cavity (3). The outer diameter of the second circular part (7.2) is smaller than the outer diameter of the third circular part (7.4). The outer diameter of the third circular part (7.4) is adapted to the inner diameter of the partition (4). The bottom height of the third circular part (7.4) is smaller than the bottom height of the tip of the partition (4).

3. The intelligent spraying tool for anti-corrosion coating of anchor bolts according to claim 2, characterized in that, The inner wall of the annular cavity (3) is divided into a first ring plate (3.1) and a plurality of second ring plates (3.2) arranged sequentially from the top of the first ring plate (3.1) upwards. The first ring plate (3.1) and the second ring plate (3.2) are the same size. The nozzles (6) are evenly distributed on the first ring plate (3.1) and the plurality of second ring plates (3.2). The first ring plate (3.1) is fixed to the inner bottom wall of the annular cavity (3). The second ring plates (3.2) located at the top of the first ring plate (3.1) and the two adjacent second ring plates (3.2) are rotatably fitted together. The bottom end of the third circular part (7.4) is in contact with the top of the uppermost second ring plate (3.2). The width of the partition plate (4) is greater than the width of the paint channel (5). The sleeve (1) is provided with a control component that can control the rotation of each second ring plate (3.2) so that the nozzles (6) are blocked by the partition plate (4).

4. The intelligent spraying tool for anti-corrosion coating of anchor bolts according to claim 3, characterized in that, The control assembly includes a guide rod (11) fixedly disposed on the inner surface of the second partition (4), a lifting rod (12) capable of moving up and down within the covering cavity (2), a spiral groove (13) disposed on the surface of the lifting rod (12) for driving the guide rod (11) to make circular motion, and an upper straight groove (14) and a lower straight groove (15) respectively disposed at the upper and lower ends of the spiral groove (13) for the guide rod (11) to enter and exit the spiral groove (13).

5. The intelligent spraying tool for anti-corrosion coating of anchor bolts according to claim 4, characterized in that, The center of the cover (7) is provided with a through hole (16) for the lifting rod (12) to pass through. The top end of the lifting rod (12) passes through the through hole (16) and is fixed to the front end of the gun body (8). The inner wall of the through hole (16) is provided with a strip slider (17) that slides in the upper straight groove (14). When the lifting rod (12) is located at the lowest position in the sleeve (1), all guide rods (11) are located in the upper straight groove (14).

6. The intelligent spraying tool for anti-corrosion coating on anchor bolts according to claim 5, characterized in that, The feeding manifold (10) is a flexible hose, and the feeding manifold (10) is located outside the lifting rod (12).

7. The intelligent spraying tool for anti-corrosion coating of anchor bolts according to claim 5, characterized in that, The inner surface of the partition (4) is provided with a groove (18), and a baffle group (19) is provided between two adjacent second ring plates (3.2) that can be displaced in the groove (18) along the inner circumferential direction. The two adjacent baffle groups (19) are respectively located in two adjacent grooves (18). The baffle group (19) includes a long baffle (19.1) and a short baffle (19.2). The top end of the long baffle (19.1) is fixed to the surface of the upper second ring plate (3.2) of the two adjacent second ring plates (3.2), and the short baffle (19.2) is fixed to the surface of the lower second ring plate (3.2) of the two adjacent second ring plates (3.2). The bottom end of the long baffle (19.1) extends to the surface of the lower second ring plate (3.2) and contacts the short baffle (19.2).

8. The intelligent spraying tool for anti-corrosion coating of anchor bolts according to claim 7, characterized in that, When the first circular part (7.1) rotates and engages with the top of the outer inner wall of the annular cavity (3), and the spray hole (6) is aligned with the corresponding paint channel (5), the short baffle (19.2) contacts one side of the inner wall of the groove (18), and when the spray hole (6) is blocked by the partition (4), the long baffle (19.1) contacts the other side of the inner wall of the groove (18).

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