A downhole walking device monitoring apparatus
By integrating laser sensors and a cleaning ring monitoring device into the downhole traveling equipment, the problem of traditional detection requiring shutdown has been solved, enabling online detection and cleaning, improving efficiency and accuracy, and ensuring the safe and continuous operation of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- YICHANG HUAXI MINING CO LTD
- Filing Date
- 2025-09-28
- Publication Date
- 2026-07-24
AI Technical Summary
Traditional inclined shaft assisted walking equipment needs to be shut down when the wire rope wear is detected, which affects efficiency and is inconvenient to use.
A monitoring device for underground traveling equipment was designed, which uses laser sensors and cleaning rings to detect and clean cables in real time. The device includes components such as winches, drive motors, transmission structures, winding wheels, baffles, fixed rollers, and guide rollers to achieve online monitoring and cleaning.
This technology enables real-time inspection and cleaning of cables without interrupting equipment operation, improving inspection efficiency and accuracy, reducing equipment downtime, and ensuring the continuity and safety of underground operations.
Smart Images

Figure CN224547754U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of mine walking equipment detection technology, specifically a monitoring device for underground walking equipment. Background Technology
[0002] An inclined shaft assistive walking device is used in inclined shaft environments such as mines and tunnels to help personnel walk more easily and safely within the shaft. It provides auxiliary power to personnel walking in the inclined shaft through mechanical transmission, electric drive, or other power sources, reducing physical exertion and improving walking efficiency and safety. The device is typically used in conjunction with tracks, wire ropes, and other facilities, utilizing friction or other forces to achieve its assistive function.
[0003] The most important component is the wire rope, which plays a crucial role in traction and load-bearing. During equipment operation, the wire rope will rub against various components and be subjected to multiple forces such as tension and bending, causing its surface to gradually wear down. If the wear exceeds a certain limit, the strength and load-bearing capacity of the wire rope will decrease significantly, potentially leading to breakage, equipment failure, or even serious safety accidents.
[0004] Traditional inspection requires the inclined shaft assist walking equipment to be shut down before the wire rope can be inspected, which affects efficiency and is not convenient to use. Based on this, this application provides a monitoring device for underground walking equipment. Utility Model Content
[0005] To address the shortcomings of existing technologies, this utility model provides a monitoring device for downhole walking equipment, which solves the problem that traditional detection methods require the wire rope to be inspected after the inclined shaft assist walking equipment is shut down, which affects efficiency and is not convenient to use.
[0006] The monitoring device for underground traveling equipment of this utility model includes a winch for cable winding, and a monitoring device is provided at the winding area of the winch for detecting and monitoring the cable. The winch includes a base plate, a drive motor is provided on the top of the base plate, a transmission structure is provided at the output end of the drive motor, and a winding wheel is provided on one side of the transmission structure. The drive motor drives the transmission structure to achieve the rotation of the winding wheel. The base plate has a snap-fit area on the side near the winding wheel, and a plug hole is provided on the bottom inner side of the snap-fit area. The inner side of the plug hole is compatible with the monitoring device. The monitoring device includes two symmetrically arranged baffles. Two symmetrically arranged fixed rollers are arranged on one side of the two baffles that are close to each other. A laser sensor and a cleaning ring are respectively installed on the two fixed rollers for cleaning the cable and detecting it through the laser detection sensor.
[0007] As a further improvement of this utility model, the two baffles are provided with screw holes on the side that is close to each other, and the fixed roller is provided with fixing protrusions at both ends, the fixing protrusions being adapted to the screw holes.
[0008] As a further improvement of this utility model, a positioning groove is provided in the middle of the side of the two baffles that are close to each other, between the two screw holes. A guide roller is installed on the inner side of the positioning groove, and the diameter of the guide roller is larger than the diameter of the fixed roller.
[0009] As a further improvement of this utility model, both ends of the guide roller are provided with positioning protrusions, and the positioning protrusions are rotatably connected to the positioning groove.
[0010] As a further improvement of this utility model, the top of both fixed rollers is provided with a downward-facing mounting surface, and the mounting surface is provided with locking holes at both ends of the fixed rollers.
[0011] As a further improvement of this utility model, the inner sides of the two sets of card holes are respectively connected to the cleaning ring and the laser detection sensor, and are arranged symmetrically with the guide roller as the central axis.
[0012] As a further improvement of this utility model, a support plate is provided at the bottom of the cleaning ring, and a protrusion adapted to the card hole is provided at the bottom of the support plate for fixing the cleaning ring.
[0013] As a further improvement of this utility model, one of the baffles is provided with a plug rod on one side, the plug rod being adapted to a plug hole opened on the base plate for fixing the two baffles.
[0014] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention uses a laser detection sensor to continuously monitor the surface condition of cables without requiring equipment shutdown, greatly improving detection efficiency, reducing equipment downtime caused by detection, and ensuring the continuity of underground operations. Furthermore, the winch base plate is equipped with a snap-fit area and a plug-in hole. The baffle of the monitoring device is adapted to the plug-in hole of the base plate through the plug-in rod, so as to achieve quick installation and fixation. At the same time, the fixed roller is connected to the screw hole of the baffle through the fixed protrusion, the guide roller is rotatably connected to the positioning groove of the baffle through the positioning protrusion, and the cleaning ring and laser detection sensor are connected to the fixed roller through the snap-fit hole. These designs make the installation of each component of the device convenient and facilitate rapid construction and maintenance in the underground environment. Meanwhile, the cleaning ring and laser detection sensors of the monitoring device are symmetrically arranged with the guide roller as the central axis. As the cable passes through, the laser detection sensors on both sides can detect the cable from different angles. This symmetrical layout can obtain more comprehensive information about the cable surface, and compared with the traditional single detection method, it can more accurately detect defects such as wear and scratches on the cable surface, improving the accuracy and reliability of the detection. Furthermore, before testing, the cleaning ring cleans the cable surface to remove dust, oil, and other impurities. A cleaner cable surface allows the laser detection sensor to more clearly identify the cable's surface condition, reducing detection errors caused by impurities and further improving detection accuracy. Attached Figure Description
[0015] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a three-dimensional structural diagram of the winch of this utility model; Figure 2 This is a front view structural diagram of the winch of this utility model; Figure 3 This is a top view schematic diagram of the combination of the winch and monitoring device of this utility model; Figure 4 This is a three-dimensional structural diagram of the monitoring device of this utility model; Figure 5 This is a three-dimensional structural diagram of the monitoring device of this utility model from another angle; Figure 6 This is a top view of the monitoring device of this utility model.
[0016] In the diagram: 1. Winch; 2. Monitoring device; 3. Cleaning ring; 4. Laser detection sensor; 5. Support plate; 11. Base plate; 12. Drive motor; 13. Transmission structure; 14. Snap-fit area; 15. Insertion hole; 16. Rewinding wheel; 21. Baffle; 22. Positioning groove; 23. Snap hole; 24. Fixed roller; 25. Positioning protrusion; 26. Connecting rod; 27. Mounting plane; 28. Screw hole; 29. Guide roller; 210. Fixed protrusion. Detailed Implementation
[0017] The following illustrations will reveal several embodiments of the present invention. For clarity, many physical details will be described in the following description. However, it should be understood that these physical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these physical details are not essential. Furthermore, for the sake of simplicity, some conventional structures and components will be shown in a simple schematic manner in the illustrations.
[0018] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.
[0019] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4 Inclined shaft assist walking equipment is used in inclined shaft environments such as mines and tunnels. It provides auxiliary power for personnel to walk in inclined shafts through mechanical transmission, electric drive and other means, which can reduce physical consumption, improve walking efficiency and safety. It is often used in conjunction with tracks, wire ropes and other means to achieve assistance through friction.
[0020] Wire ropes in inclined shaft auxiliary walking equipment serve the functions of traction and load-bearing. During operation, the wire ropes rub against various components and bear tensile and bending forces, causing gradual wear on their surface. When the wear exceeds the limit, their strength and load-bearing capacity decrease significantly, potentially leading to breakage and causing equipment failure and safety accidents. Traditional inspections require the equipment to be shut down, affecting work efficiency and causing inconvenience. Based on this, this application provides a monitoring device 2 for underground traveling equipment, including a winch 1 for cable winding, and a monitoring device 2 is provided at the winding area of the winch 1 for detecting and monitoring the cable. The winch 1 includes a base plate 11, a drive motor 12 is provided on the top of the base plate 11, a transmission structure 13 is provided at the output end of the drive motor 12, and a winding wheel 16 is provided on one side of the transmission structure 13. The drive motor 12 drives the transmission structure 13 to achieve the rotation of the winding wheel 16. A snap-fit area 14 is provided on the side of the base plate 11 near the winding wheel 16. A plug-in hole 15 is provided on the bottom inner side of the snap-fit area 14. The inner side of the plug-in hole 15 is adapted to the monitoring device 2. The monitoring device 2 includes two symmetrically arranged baffles 21. Two symmetrically arranged fixed rollers 24 are arranged on the side of the two baffles 21 that are close to each other. A laser sensor and a cleaning ring 3 are respectively installed on the two fixed rollers 24 for cleaning the cable and detecting it through the laser detection sensor 4.
[0021] The winch 1 includes a base plate 11, which can be fixed to a suitable location underground by bolts or other means. A drive motor 12 is installed on top of the base plate 11. The drive motor 12 can be an explosion-proof motor suitable for the underground environment to ensure safe operation in underground environments where flammable and explosive gases may be present.
[0022] The output end of the drive motor 12 is connected to a transmission structure 13, which can be a belt drive, chain drive, or gear drive, etc. In this embodiment, a gear drive is used. A drive gear is mounted on the output shaft of the drive motor 12, and the drive gear meshes with a driven gear. The driven gear is mounted on the shaft of the take-up reel 16. When the drive motor 12 starts, the drive gear rotates, driving the driven gear to rotate, which in turn causes the take-up reel 16 to rotate, realizing the winding and unwinding operations of the cable.
[0023] A snap-fit area 14 is provided on the side of the base plate 11 near the winding wheel 16, and a plug-in hole 15 is provided on the bottom inner side of the snap-fit area 14. The shape and size of the plug-in hole 15 are adapted to the monitoring device 2 for accurate installation of the monitoring device 2, ensuring that the monitoring device 2 can stably detect and monitor the cable during the winding process.
[0024] The monitoring device 2 includes two symmetrically arranged baffles 21. These two baffles 21 can be installed in the insertion holes 15 of the snap-fit area 14 by means of bolts or the like, so as to achieve a fixed connection with the winch 1. Two symmetrically arranged fixed rollers 24 are provided on the side of the two baffles 21 that are close to each other. The two ends of the fixed rollers 24 are respectively rotatably connected to the baffles 21 to ensure that the cable can move smoothly when passing through the fixed rollers 24.
[0025] A laser sensor and a cleaning ring 3 are respectively installed on the two fixed rollers 24. The cleaning ring 3 can be made of materials with cleaning function such as sponge or brush, and its inner diameter is slightly smaller than the outer diameter of the cable. When the cable passes through the cleaning ring 3, the cleaning ring 3 can fully contact the surface of the cable to clean the dust, oil and other impurities on the surface of the cable. During the cable winding process, the cable continuously passes through the cleaning ring 3, thereby achieving continuous cleaning of the cable surface.
[0026] A laser sensor is mounted on another fixed roller 24. Its working principle involves emitting a laser beam that illuminates the cable surface. By receiving the reflected laser signal, it analyzes the cable surface's contour and condition. When defects such as wear or scratches exist on the cable surface, the reflected laser signal changes. The laser sensor converts these changes into electrical signals and transmits them to subsequent data analysis and processing equipment. This data analysis and processing equipment can be pre-set with parameters representing a normal cable surface. When the received signal exceeds this range, a problem is detected, and an alarm signal is issued to alert personnel for timely intervention.
[0027] When the downhole traveling equipment needs to wind up the cable, the drive motor 12 is started. The drive motor 12 drives the winding wheel 16 to rotate through the transmission structure 13, and the cable begins to wind up. During the winding process, the cable passes through the cleaning ring 3 and the laser sensor in sequence. The cleaning ring 3 cleans the surface of the cable and removes impurities; the laser sensor performs real-time detection on the cleaned cable and transmits the detection data to the data analysis and processing equipment to realize the detection and monitoring of the cable.
[0028] The monitoring device 2 for the underground traveling equipment described above can be used to clean and inspect cables in real time without affecting the normal operation of the underground traveling equipment. This allows for the timely detection of problems such as cable wear, improving the safety and reliability of the equipment. At the same time, it avoids the drawback of traditional inspection methods that require equipment shutdown, thus improving work efficiency.
[0029] Please see Figure 3 , Figure 4 , Figure 5 as well as Figure 6 The two baffles 21 are provided with screw holes 28 on the side that are close to each other, and the fixed roller 24 is provided with fixed protrusions 210 at both ends, which are adapted to the screw holes 28.
[0030] A positioning groove 22 is provided in the middle of the side of the two baffles 21 that are close to each other, between the two screw holes 28. A guide roller 29 is installed on the inner side of the positioning groove 22. The diameter of the guide roller 29 is larger than the diameter of the fixed roller 24.
[0031] Both ends of the guide roller 29 are provided with positioning protrusions 25, which are rotatably connected to the positioning groove 22.
[0032] The top of each of the two fixed rollers 24 has a downward-facing mounting surface 27, and the mounting surface 27 has a locking hole 23 at both ends of the fixed roller 24.
[0033] Based on the aforementioned monitoring device 2 for underground traveling equipment, screw holes 28 are provided on the side of the two baffles 21 that are close to each other, which provides a specific connection method for the installation of the fixed roller 24. Both ends of the fixed roller 24 are provided with fixing protrusions 210, and the fixing protrusions 210 are adapted to the screw holes 28. During actual installation, the operator can align the fixing protrusions 210 at both ends of the fixed roller 24 with the screw holes 28 on the baffles 21, and then use a suitable tool, such as a screwdriver, to screw the fixing protrusions 210 into the screw holes 28. This threaded connection method ensures that the fixed roller 24 is stably installed between the two baffles 21, preventing the fixed roller 24 from loosening or shifting during equipment operation, thereby ensuring that the laser sensor and cleaning ring 3 can accurately clean and inspect the cables.
[0034] Specifically, a positioning groove 22 is provided in the middle of the side of the two baffles 21 that are close to each other, between the two screw holes 28. The positioning groove 22 provides an installation position for the guide roller 29. The diameter of the guide roller 29 is larger than that of the fixed roller 24. This design allows the guide roller 29 to better guide the cable in the whole device. Both ends of the guide roller 29 are provided with positioning protrusions 25, which are rotatably connected to the positioning groove 22. When installing the guide roller 29, the operator only needs to align the positioning protrusions 25 at both ends of the guide roller 29 with the positioning groove 22 and then put it into the positioning groove 22. Since the positioning protrusions 25 are rotatably connected to the positioning groove 22, the guide roller 29 can rotate freely in the positioning groove 22. When the cable passes through the guide roller 29 during the winding process, the guide roller 29 can automatically adjust the rotation direction according to the movement direction and tension of the cable, so that the cable passes more smoothly through the cleaning ring 3 and laser sensor on the fixed roller 24, avoiding the phenomenon of cable jamming or deviation, and improving the efficiency and accuracy of cable detection and cleaning.
[0035] Both fixed rollers 24 have downward-facing mounting surfaces 27 at their tops. Each end of the mounting surface 27 has locking holes 23. The mounting surfaces 27 provide a flat base for the laser sensor and cleaning ring 3, facilitating accurate mounting of these components onto the fixed rollers 24. The locking holes 23 further secure the laser sensor and cleaning ring 3; during installation, they can be fixed to the mounting surfaces 27 using clips that fit the locking holes 23. This prevents the laser sensor and cleaning ring 3 from slipping or wobbling during the rotation of the fixed rollers 24, ensuring stable cleaning and detection of the cables. When the downhole traveling equipment begins to wind up the cable, the cable first passes through the guide roller 29. The guide roller 29, with its large diameter and rotatable characteristics, provides initial guidance and tension adjustment for the cable, allowing it to enter the area of the fixed roller 24 at a suitable angle and state. Next, the cable passes through the cleaning ring 3 and the laser sensor in sequence. Driven by the fixed roller 24, the cleaning ring 3 cleans the surface of the cable, removing dust, oil, and other impurities. At the same time, the laser sensor monitors the cleaned cable in real time and transmits the detected signals to the data analysis and processing equipment. Throughout the process, the fixed roller 24 is stably installed between the baffles 21 through the connection between the fixed protrusion 210 and the screw hole 28. The guide roller 29 achieves free rotation through the cooperation of the positioning protrusion 25 and the positioning groove 22. The laser sensor and the cleaning ring 3 are firmly installed on the fixed roller 24 through the design of the mounting plane 27 and the locking hole 23, which together ensure the stable operation and efficient work of the downhole traveling equipment monitoring device 2.
[0036] Please see Figure 4 , Figure 5 , Figure 6 The inner sides of the two sets of card holes 23 are connected to the cleaning ring 3 and the laser detection sensor 4 respectively, and are symmetrically arranged with the guide roller 29 as the central axis.
[0037] The bottom of the cleaning ring 3 is provided with a support plate 5, and the bottom of the support plate 5 is provided with a protrusion that matches the card hole 23 for fixing the cleaning ring 3.
[0038] One of the baffles 21 has a plug rod 26 on one side, which is adapted to the plug hole 15 opened on the base plate 11 for fixing the two baffles 21.
[0039] Two sets of locking holes 23 are located at both ends of the mounting plane 27 of the two fixed rollers 24, and their inner sides are connected to the cleaning ring 3 and the laser detection sensor 4, respectively, ensuring that the cleaning ring 3 and the laser detection sensor 4 can be stably installed on the fixed rollers 24. With the guide roller 29 as the central axis, the cleaning ring 3 and the laser detection sensor 4 are symmetrically arranged. When the cable is guided from the guide roller 29 into the area of the fixed roller 24, the symmetrical arrangement of the cleaning ring 3 and the laser detection sensor 4 can make the cable be evenly acted on on both sides. For example, when the cable passes through the cleaning ring 3, the cleaning ring 3 can clean the cable and improve the cleaning effect; when the laser detection sensor 4 performs detection, the symmetrical layout can detect the cable from different angles, making the detection results more comprehensive and accurate, and better able to detect defects such as wear and scratches that may exist on the surface of the cable.
[0040] The bottom of the cleaning ring 3 is provided with a support plate 5, which serves to support and fix the cleaning ring 3. The bottom of the support plate 5 is provided with a protrusion that matches the locking hole 23. When installing the cleaning ring 3, the operator only needs to align the protrusion at the bottom of the support plate 5 with the locking hole 23 on the mounting plane 27 of the fixed roller 24, and then insert the protrusion into the locking hole 23 to fix the cleaning ring 3. This also ensures that the cleaning ring 3 will not shake or shift during the rotation of the fixed roller 24. When the cable passes through the cleaning ring 3, the cleaning ring 3 can stably clean the surface of the cable, ensuring the consistency and stability of the cleaning effect. At the same time, this fixing method also facilitates the replacement and maintenance of the cleaning ring 3. If the cleaning ring 3 is worn or damaged after a period of use, the staff can easily remove it from the fixing roller 24 for replacement.
[0041] One side of one of the baffles 21 is provided with a plug rod 26, and the base plate 11 has a plug hole 15 that matches the plug rod 26. When installing the monitoring device 2, the operator aligns the side of the baffle 21 with the plug rod 26 with the plug hole 15 on the base plate 11, and then inserts the plug rod 26 into the plug hole 15 to fix the two baffles 21 to the base plate 11 together. This fixing method allows the monitoring device 2 to be firmly installed on the winch 1, ensuring the stability of the entire device during operation. During the operation of the underground traveling equipment, the winding and unwinding of the cable will generate a certain amount of tension and vibration. If the connection between the baffle 21 and the base plate 11 is not firm, it may cause the monitoring device 2 to shake or shift, affecting the cleaning and detection effect. By using the plug rod 26 and the plug hole 15, this situation can be effectively avoided, ensuring that the monitoring device 2 can continuously and stably clean and detect the cable. Moreover, this plug-in fixing method also facilitates the installation and disassembly of the entire monitoring device 2. When it is necessary to repair or replace parts of the monitoring device 2, the staff can easily remove it from the winch 1.
[0042] When the downhole traveling equipment begins to wind up the cable, the cable first passes through the guide roller 29, which guides and adjusts the tension of the cable. Then, the cable enters the area of the fixed roller 24. The symmetrically arranged cleaning rings 3, driven by the fixed roller 24, stably clean the surface of the cable through the fixing method of the bottom protrusion of the support plate 5 and the locking hole 23. After cleaning, the cable then passes through the symmetrically arranged laser detection sensors 4, which detect the surface of the cable and transmit the detection data to the data analysis and processing equipment. Throughout the process, the baffle 21 is fixed to the insertion hole 15 on the base plate 11 through the insertion rod 26, ensuring the stability of the monitoring device 2. This allows the entire downhole traveling equipment monitoring device 2 to complete the cleaning and detection of the cable efficiently and accurately.
[0043] The above description is merely an embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this utility model should be included within the scope of the claims of this utility model.
Claims
1. A monitoring device for underground traveling equipment, comprising a winch (1) for cable winding, wherein a monitoring device (2) is provided at the winding area of the winch (1) for detecting and monitoring the cable; Its features are: The winch (1) includes a base plate (11), a drive motor (12) is provided on the top of the base plate (11), a transmission structure (13) is provided at the output end of the drive motor (12), and a winding wheel (16) is provided on one side of the transmission structure (13). The winding wheel (16) is rotated by the drive motor (12) driving the transmission structure (13). The base plate (11) has a snap-fit area (14) on the side near the winding wheel (16). The bottom inner side of the snap-fit area (14) has a plug hole (15), and the inner side of the plug hole (15) is adapted to the monitoring device (2). The monitoring device (2) includes two symmetrically arranged baffles (21). Two symmetrically arranged fixed rollers (24) are arranged on the side of the two baffles (21) that are close to each other. A laser sensor and a cleaning ring (3) are respectively installed on the two fixed rollers (24) for cleaning the cable and detecting it through the laser detection sensor (4).
2. The monitoring device for downhole traveling equipment according to claim 1, characterized in that: The two baffles (21) are provided with screw holes (28) on the side that is close to each other, and the fixed roller (24) is provided with fixed protrusions (210) at both ends, and the fixed protrusions (210) are adapted to the screw holes (28).
3. The monitoring device for downhole traveling equipment according to claim 1, characterized in that: A positioning groove (22) is provided in the middle of the side of the two baffles (21) that are close to each other, between the two screw holes (28). A guide roller (29) is installed on the inner side of the positioning groove (22). The diameter of the guide roller (29) is larger than the diameter of the fixed roller (24).
4. The monitoring device for downhole traveling equipment according to claim 3, characterized in that: Both ends of the guide roller (29) are provided with positioning protrusions (25), and the positioning protrusions (25) are rotatably connected to the positioning groove (22).
5. The monitoring device for downhole traveling equipment according to claim 1, characterized in that: The top of each of the two fixed rollers (24) is provided with a downward-facing mounting surface (27), and the mounting surface (27) is provided with a locking hole (23) at both ends of the fixed roller (24).
6. The monitoring device for downhole traveling equipment according to claim 5, characterized in that: The inner sides of the two sets of card holes (23) are connected to the cleaning ring (3) and the laser detection sensor (4) respectively, and are symmetrically arranged with the guide roller (29) as the central axis.
7. The monitoring device for downhole traveling equipment according to claim 1, characterized in that: The bottom of the cleaning ring (3) is provided with a support plate (5), and the bottom of the support plate (5) is provided with a protrusion that matches the card hole (23) for fixing the cleaning ring (3).
8. The monitoring device for downhole traveling equipment according to claim 1, characterized in that: One of the baffles (21) is provided with a plug rod (26) on one side. The plug rod (26) is adapted to the plug hole (15) opened on the base plate (11) for fixing the two baffles (21).