A weatherproof enclosure for outdoor communication engineering equipment
By introducing airbags and scraper assemblies into the weatherproof enclosure of outdoor communication engineering equipment, and utilizing water level sensors and PLC controllers to achieve automatic lifting and cleaning of the cabinet, the problems of equipment immersion and jamming are solved, ensuring the safe and stable operation of the equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANDONG POST & TELECOM ENG CO LTD
- Filing Date
- 2025-04-09
- Publication Date
- 2026-06-30
AI Technical Summary
Traditional outdoor communication equipment lacks waterproof and anti-immersion features, which can lead to water damage during heavy rains, affecting equipment safety and communication functionality.
Design a weatherproof outer shell for outdoor communication engineering equipment, comprising components such as an airbag, a water level sensor, a PLC controller, a sliding frame, a screw, a slider, a drive frame, and a ring scraper. The water level sensor detects the water level, the PLC controls the airbag to lift the cabinet using buoyancy, and a timed motor drives the scraper to clean the sliding rod, achieving the functions of water immersion prevention and anti-jamming.
Effectively prevents equipment from being submerged in water, ensures equipment safety, prevents deposits from affecting the operation of the lifting mechanism, and maintains the safety and stability of the equipment.
Smart Images

Figure CN224439325U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of communication engineering cabinet technology, and in particular to a weatherproof shell for outdoor communication engineering equipment. Background Technology
[0002] Traditional weatherproof enclosures for outdoor communication equipment mainly rely on sealing strips, screw fastening, and high-protection-level materials to meet basic waterproof and dustproof requirements. However, factors such as heavy rainfall or sewer blockage may cause the water level at the location of the communication equipment cabinet to rise abnormally and submerge the cabinet. Traditional weatherproof enclosures do not have the function of preventing equipment from being submerged due to rising water levels.
[0003] Common weatherproof enclosures for outdoor communication equipment only contain rainproof components, which can prevent water ingress caused by rainfall. However, they lack anti-immersion and anti-jamming functions, which cannot guarantee the safety of the cabinet equipment. In heavy rain, the water level may be too high, causing the cabinet to be submerged. This can lead to moisture damage and short circuits in the internal electronic components, and deposits may affect the vertical movement of the cabinet, thus compromising the safety of the equipment.
[0004] Therefore, given that the aforementioned weatherproof enclosures for outdoor communication equipment lack anti-immersion and anti-jamming functions, and are prone to damage due to water damage caused by excessively high water levels during rainfall, there is an urgent need to design a new type of weatherproof enclosure for outdoor communication equipment. Utility Model Content
[0005] To overcome the common problem of outdoor communication equipment lacking waterproof and anti-immersion features, such as the cabinet being submerged by high water levels during rainfall, which can damage the equipment and cause communication malfunctions.
[0006] The technical solution of this utility model is as follows: a weatherproof outer shell for outdoor communication engineering equipment, including a cabinet; it also includes a base, an airbag, a waterproof air pump, a water level sensor, a PLC controller, a sliding frame, a screw, a slider, a drive frame, an annular scraper, a sliding sleeve, a sliding rod, and a limiting ring. The cabinet has a base at its bottom, an airbag on the top of its inner surface, a waterproof air pump connected to the top right side of the base's inner surface, the output end of the waterproof air pump connected to the airbag, and a water level sensor corresponding to the position of the waterproof air pump on the top right side of the base's inner surface. The bottom of the cabinet is near... A PLC controller is located near the water-resistant air pump. The PLC controller is electrically connected to the water level sensor. A sliding frame is located on the rear side of the cabinet. A screw is installed inside the sliding frame. A slider is threaded around the screw. A drive frame is located behind the slider. Eight annular scrapers are symmetrically arranged on the left and right sides of the top and bottom of the drive frame. Four sliding sleeves are located at the front and rear ends of the bottom of the left and right sides of the cabinet. Each of the four sliding sleeves contains a sliding rod. The four sliding rods are slidably connected to the drive frame and the annular scrapers. Limit rings are provided at the top and bottom of the four sliding rods.
[0007] Preferably, by setting up an airbag, a water level sensor detects that the water level exceeds the danger height, and the PLC controller controls a waterproof water pump to inflate the airbag. The inflated airbag pushes the cabinet upwards by the buoyancy of the water. When there are attachments on the sliding rod, a timer motor is activated. The timer motor drives the screw to rotate, which in turn moves the slider on the screw up and down. The slider moves the annular scraper on the drive frame up and down, so as to achieve the purpose of lifting the cabinet by buoyancy and automatically cleaning the sliding rod by the annular scraper. This solves the common problem of weatherproof shells for outdoor communication engineering equipment, which only contain rainproof components and can prevent water ingress caused by rain, but lack the cabinet lifting and cleaning functions, cannot guarantee the safety of the cabinet equipment, and have the problem of the cabinet being submerged in water when the water level is too high during heavy rain, resulting in damage to electronic components and attachments obstructing the lifting of the cabinet.
[0008] Preferably, a timer motor is installed at the top of the sliding frame. The timer motor is electrically connected to the PLC controller. The output end of the timer motor passes through the top of the sliding frame and is connected to the screw. The other end of the screw is rotatably connected to the bottom of the sliding frame. A rainproof cover is installed at the top of the sliding frame.
[0009] As a preferred option, louvers are provided on the upper left and right sides of the cabinet unit, and a fan is located in the center of the lower inner surface of the cabinet unit.
[0010] As a preferred option, a lampshade is installed on the upper inner surface of the cabinet, and a light is installed inside the lampshade.
[0011] Preferably, the front surface of the cabinet unit is connected to a cabinet door via a hinge. A handle is provided on the left end of the front surface of the cabinet door, and a door stop is provided on the upper right corner of the rear surface of the cabinet door. The other end of the door stop is connected to the top of the cabinet unit.
[0012] Preferably, the top of the cabinet unit is equipped with a drainage slope, and the front surface of the base is equipped with four drainage outlets.
[0013] Preferably, the top of the limiting ring at the lower end of the sliding rod is provided with four fixing grooves, and fixing screws are threaded into the interior of each of the four fixing grooves.
[0014] The beneficial effects of this utility model are:
[0015] 1. By setting up an airbag, when the water level sensor detects that the water level exceeds the safety threshold, the PLC controller controls the waterproof air pump to inject gas into the airbag. The buoyancy of the airbag in the water pushes the cabinet, causing the cabinet to move upward along the sliding rod, so as to realize the function of raising the cabinet and avoiding water immersion.
[0016] 2. By setting a timer motor and starting it, the timer motor drives the screw at the output end to rotate, which in turn drives the slider connected to the screw threaded on the screw. The slider drives the drive frame to move up and down, and the drive frame drives the scraper to move up and down. The scraper removes the protruding attachments around the sliding rod, thereby achieving the anti-jamming function. Attached Figure Description
[0017] Figure 1 The diagram shown is a front view of the overall structure of the weatherproof shell of an outdoor communication engineering device according to this utility model.
[0018] Figure 2 The image shown is an exploded rear view of the overall weatherproof shell of an outdoor communication engineering device according to this utility model.
[0019] Figure 3 This utility model presents a weatherproof outer shell for outdoor communication engineering equipment. Figure 2 Enlarged view of point A in the middle;
[0020] Figure 4 The diagram shown is a top view of the structure of a weatherproof outer shell base for an outdoor communication engineering device according to this utility model.
[0021] Figure 5 The diagram shown is a schematic representation of the internal structure of a weatherproof outer shell cabinet for outdoor communication engineering equipment according to this utility model.
[0022] Figure 6 The diagram shown is a schematic diagram of the top structure of a weatherproof outer shell cabinet for outdoor communication engineering equipment according to this utility model.
[0023] Explanation of reference numerals in the attached diagram: 1. Base; 2. Drain outlet; 3. Airbag; 4. Waterproof air pump; 5. Water level sensor; 6. PLC controller; 7. Sliding frame; 8. Rainproof cover; 9. Timer motor; 10. Screw; 11. Slider; 12. Drive frame; 13. Annular scraper; 14. Cabinet unit; 15. Sliding sleeve; 16. Sliding rod; 17. Louver; 18. Fan; 19. Cabinet door; 20. Handle; 21. Lampshade; 22. Door stopper; 23. Drainage slope; 24. Lighting lamp; 25. Limiting ring; 26. Fixing groove; 27. Fixing screw. Detailed Implementation
[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0025] Please see Figures 1-6 This utility model provides an embodiment of a weatherproof outer shell for outdoor communication engineering equipment, including a cabinet 14; it also includes a base 1, an airbag 3, a waterproof air pump 4, a water level sensor 5, a PLC controller 6, a sliding frame 7, a screw 10, a slider 11, a drive frame 12, an annular scraper 13, a sliding sleeve 15, a sliding rod 16, and a limiting ring 25. The base 1 is located at the bottom of the cabinet 14, the airbag 3 is located at the top of the inner surface of the base 1, and the waterproof air pump 4 is connected to the top of the right side of the inner surface of the base 1. The output end of the waterproof air pump 4 is connected to the air bag 3. A water level sensor 5 is installed on the top right side of the inner surface of the base 1, corresponding to the position of the waterproof air pump 4. A PLC controller 6 is installed on the bottom inner surface of the cabinet 14 near the waterproof air pump 4. The PLC controller 6 is electrically connected to the water level sensor 5. A sliding frame 7 is installed on the rear side of the cabinet 14. A screw 10 is installed inside the sliding frame 7. A slider 11 is threaded around the screw 10. A drive frame 12 is installed on the rear side of the slider 11. The top of the drive frame 12... Eight annular scrapers 13 are symmetrically arranged on the left and right sides of the bottom of the cabinet 14. Four sliding sleeves 15 are arranged at the front and rear ends of the bottom of the left and right sides of the cabinet 14. Each of the four sliding sleeves 15 has a sliding rod 16 installed inside. The four sliding rods 16 are slidably connected to the drive frame 12 and the annular scrapers 13. Limit rings 25 are provided at the top and bottom of the four sliding rods 16. By setting an inflatable airbag 3 and a water level sensor 5 of model FKC-20, when the water level exceeds the safety threshold, the PLC controller 6 controls the waterproof air pump 4 to inject gas into the airbag 3 to generate buoyancy and lift the main body of the cabinet 14, so as to avoid the equipment from being submerged in water. At the same time, by timed activation of the timer motor 9, the annular scrapers 13 on the drive frame 12 are driven to reciprocate between the limit rings 25 of the sliding rods 16, so as to realize the function of automatically removing impurities on the surface of the sliding rods 16, thereby maintaining the cleanliness of the equipment lifting channel and solving the problems of equipment damage caused by abnormal rise in water level and the impact of attachment on the mechanical structure on the operational stability.
[0026] Please see Figures 2-6 In this embodiment, a timer motor 9 is provided at the top of the sliding frame 7. The timer motor 9 is electrically connected to the PLC controller 6. The output end of the timer motor 9 passes through the top of the sliding frame 7 and is connected to the screw 10. The other end of the screw 10 is rotatably connected to the bottom of the sliding frame 7. A rainproof cover 8 is provided at the top of the sliding frame 7. Louvers 17 are provided at the upper ends of both the left and right sides of the cabinet 14. A fan 18 is provided at the center of the lower inner surface of the cabinet 14. A lampshade 21 is provided on the upper inner surface of the cabinet 14. A lighting lamp 24 is provided inside the lampshade 21. A drainage slope 23 is provided at the top of the cabinet 14. The front surface of the base 1 is provided with four drainage holes 2. The rainproof cover 8 protects the timer motor 9 from water immersion. The louvers 17 on both sides of the cabinet 14 are tilted outward to allow air circulation and block most of the rainwater. The fan 18 promotes air circulation and dissipates heat for the equipment inside the cabinet 14. The lamp cover 21 blocks moisture to protect the lighting lamp 24. The drainage slope 23 can prevent water from accumulating on the top of the cabinet 14. The drainage holes 2 can prevent water from accumulating inside the base 1 during normal rainy weather, preventing the cabinet 14 from accidentally rising in non-emergency situations, which could cause the power cord and other connecting wires to break and affect normal use.
[0027] Please see Figures 1-6 In this embodiment, the front surface of the cabinet 14 is movably connected to the cabinet door 19 via a hinge. A handle 20 is provided at the left end of the front surface of the cabinet door 19, and a door stopper 22 is provided at the upper right corner of the rear surface of the cabinet door 19. The other end of the door stopper 22 is connected to the top of the cabinet 14. The top of the limiting ring 25 at the lower end of the sliding rod 16 has four fixing grooves 26. Each of the four fixing grooves 26 is threaded with a fixing screw 27. The door 19 of the cabinet 14 can be stably opened and closed by the hinge of the door stopper 22. The fixing grooves 26 are fixed to the ground by the fixing screws 27 to ensure the stability of the sliding rod 16.
[0028] During operation, the drain outlet 2 on the front surface of the base 1 prioritizes drainage. If the water level rises abnormally due to external factors such as rainfall and sewer blockage, the water level sensor 5 at the bottom of the base 1 detects that the water level exceeds the preset safety line. The PLC controller 6 controls the waterproof air pump 4 to inflate the airbag 3. Using the buoyancy in the water, the main body of the cabinet 14 is lifted smoothly along the sliding rod 16 to isolate the equipment from the water. This achieves the function of actively avoiding water when the water level is abnormal. When the attachment attaches to the sliding rod 16, the timer motor 9 is started, causing the precision screw 10 in the sliding frame 7 to rotate. This drives the threaded slider 11 to move up and down. Through the rigidly connected drive frame 12, the threaded annular scraper 13 is controlled to scrape the entire sliding rod 16 to remove the obstruction to the lifting mechanism at regular intervals.
[0029] Through the above steps, by setting up airbag 3, when the water level sensor 5 detects that the water level exceeds the safety threshold, the PLC controller 6 will activate the waterproof air pump 4 to inject gas into airbag 3. The buoyancy of airbag 3 in water pushes cabinet 14, causing cabinet 14 to move upward along sliding rod 16, realizing the function of raising cabinet 14 and avoiding water immersion. By setting up timer motor 9, when the timer motor 9 is started, the timer motor 9 drives the screw 10 at the output end to rotate, driving the slider 11 threaded on the screw 10. The slider 11 drives the drive frame 12 to move up and down. 12 drives the ring scraper 13 to move up and down, realizing the function of cleaning and removing dirt from the sliding rod 16 when it is contaminated by attached substances. This solves the problem that the existing weatherproof shell structure is only equipped with basic rainproof components, which can cope with the water ingress caused by normal rainfall, but is not equipped with a cabinet lifting mechanism and anti-jamming module, resulting in insufficient equipment safety protection capabilities. In extreme rainstorms and drainage failure scenarios, the excessively high water level formed by rainwater accumulation can easily cause cabinet water immersion accidents, which in turn lead to the risk of damage to electronic components. The accumulation of external attachments will directly affect the normal operation of the cabinet lifting mechanism.
[0030] Preferably, in a specific application scenario, each structural component is described in a preferred or alternative manner.
[0031] The base structure serves as the fundamental support for the entire device, employing a robust frame design typically composed of crisscrossing steel beams to form a stable load-bearing platform. Its connection is achieved through anchor bolts or welding, securely anchoring it to the riverbank or other fixed support points to ensure the device remains stable during salvage operations. Its location is at the very bottom of the device, with the surface in contact with the water remaining level, providing a stable foundation for other components. The base dimensions are customizable based on the scale of the salvage operation and the application scenario. Small device bases may have an area of a few square meters, while large device bases can reach tens of square meters or even larger. The length-to-width ratio is usually optimized based on actual needs and the aquatic environment to ensure stability and ease of operation. The material used is high-strength, corrosion-resistant steel, such as stainless steel or specially treated carbon steel. The steel possesses excellent strength and toughness, capable of withstanding the weight of the device itself and various external forces generated during salvage, while its corrosion resistance effectively combats chemical erosion in the aquatic environment, extending the device's service life.
[0032] The salvage arm structure consists of multiple telescopic arm sections connected by joints to achieve multi-angle rotation. The arm sections typically contain hydraulic or electric drive units to control extension, retraction, and rotation. One end is connected to a rotating platform on the base via a high-strength pin, allowing for 360-degree rotation and facilitating salvage operations in different directions. The arm sections are connected by a nesting and locking mechanism, ensuring both rigidity during extension and flexible retraction. The arm is mounted on a rotating platform above the base, initially in a horizontal position, with the angle and extension length adjustable according to the location of the floating object. The total length of the arm is determined by the salvage area requirements; smaller units typically have arm lengths of 5-10 meters, while larger units can reach tens of meters. The diameter and wall thickness of each arm section are designed and calculated based on the load to ensure sufficient strength. The main body of the arm is made of lightweight, high-strength aluminum alloy or carbon fiber composite material. Aluminum alloys have a good strength-to-weight ratio and corrosion resistance, while carbon fiber composites have higher strength and lower weight, which can effectively reduce the weight of the boom, improve the control performance and energy utilization efficiency of the device, and ensure long-term stable operation in complex aquatic environments.
[0033] The salvage net has a funnel-shaped structure, consisting of a frame and a net body. The frame is made of sturdy metal to support the net and maintain its shape. The net body is woven from high-strength, corrosion-resistant nylon or polyester fiber, with the mesh size selected based on the size of the floating debris to be salvaged. It is connected to the end of the salvage arm via hooks or bolts, ensuring the net does not detach during salvage. Its position is at the very front of the extended salvage arm, directly contacting the floating debris in the water during operation. The net's opening diameter is determined by the scale of the salvage operation and the distribution of common floating debris; small nets typically have an opening diameter of 1-2 meters, while large nets can reach several meters. The net's depth is usually between 0.5-1.5 meters to ensure it can hold a certain amount of floating debris. The frame is made of stainless steel or aluminum alloy, offering good strength and corrosion resistance, allowing for prolonged use in water. The nylon or polyester fiber material of the net has high strength and abrasion resistance, as well as corrosion resistance, which can effectively prevent the net from being torn or corroded during the salvage process, ensuring the continuity and effectiveness of the salvage operation.
[0034] The drive unit structure includes components such as a hydraulic pump, motor, and reducer. The hydraulic drive unit pressurizes hydraulic oil through the pump and delivers it to various actuators (such as hydraulic cylinders) via oil pipes, enabling the extension, retraction, and rotation of the retrieval arm. The electric drive unit uses a motor to drive a reducer, converting the motor's high-speed, low-torque output into a low-speed, high-torque output to drive the rotating platform and other mechanical components. Connections: The hydraulic pump and motor of the hydraulic drive unit are connected via a coupling, and the hydraulic pump and hydraulic cylinders are connected via high-pressure oil pipes. The motor and reducer of the electric drive unit are connected via a belt or chain, and the reducer's output shaft is connected to the transmission shaft of the rotating platform or other mechanical components via a coupling. Positions: The motor and hydraulic pump of the hydraulic drive unit are generally installed in specific locations on the base for easy maintenance and operation, while the hydraulic cylinders are installed at positions corresponding to the joints of the retrieval arm for precise motion control. The motor and reducer of the electric drive unit are typically installed near the rotating platform or other components requiring drive to minimize transmission losses. Dimensions: The dimensions of each component of the drive unit are determined based on the power requirements and load size of the device. For example, the motor power of a small device may be several kilowatts, resulting in a relatively small motor and reducer size; the motor power of a large device can reach tens of kilowatts or even higher, and the size of the motor and reducer also increases accordingly. The materials used are as follows: the motor housing is made of cast iron or aluminum alloy, providing good heat dissipation and mechanical strength. The reducer housing is usually made of cast iron, and the internal gears are made of high-strength alloy steel, heat-treated to improve hardness and wear resistance. The pump body of the hydraulic pump and the cylinder body of the hydraulic cylinder are generally made of high-quality steel to withstand the pressure of high-pressure hydraulic oil. These material choices ensure the reliability of the drive device during long-term operation and meet the performance requirements under different working conditions.
[0035] The control system structure consists of a controller, sensors, and an operation panel. The controller, typically a programmable logic controller (PLC), receives data from sensors such as water level and angle sensors to precisely control the drive unit. Sensors collect various parameters during operation, while the operation panel allows operators to input control commands and monitor the unit's operating status in real time. Connections: Sensors are connected to the controller via cables, transmitting their collected signals. The controller connects to the drive unit's motors, solenoid valves, and other actuators via output cables to control the unit. The operation panel connects to the controller via a communication cable, enabling human-machine interaction. Location: The controller is generally installed in a control cabinet, typically in a location easily accessible to operators, such as an operating room near the shore or the control center of the unit. Sensors are installed in appropriate locations depending on the parameters they monitor; for example, water level sensors are installed near the water, and angle sensors are installed at the joints of the salvage arm. The operation panel is installed in a convenient location for operators, such as a control panel in the operating room. The dimensions of the control cabinet are determined by the number and size of the controllers, power modules, relays, and other components installed inside. Small control cabinets are typically only a few tens of centimeters square, while large cabinets can be several meters high and wide. The dimensions of sensors and control panels are designed according to their functions and application scenarios, generally being compact for easy installation and operation. The control cabinet is made of stainless steel or cold-rolled steel, providing excellent protection against dust and moisture, effectively preventing the entry of electrical components. The sensor housings are made of suitable materials based on their operating environment; for example, underwater level sensors use waterproof and corrosion-resistant materials such as stainless steel or special engineering plastics. Control panels are usually made of plastic with a specially treated surface, offering good wear resistance and a pleasant tactile feel for easy operation. These material choices ensure the reliability and stability of the control system in complex environments while meeting the requirements for long-term operation of the device.
Claims
1. A weatherproof enclosure for outdoor communication equipment, comprising a cabinet (14), characterized in that: It also includes a base (1), an airbag (3), a waterproof air pump (4), a water level sensor (5), a PLC controller (6), a sliding frame (7), a screw (10), a slider (11), a drive frame (12), a ring scraper (13), a sliding sleeve (15), a sliding rod (16), and a limit ring (25). The bottom of the cabinet (14) is provided with a base (1), the top of the inner surface of the base (1) is provided with an airbag (3), the top of the right side of the inner surface of the base (1) is connected to a waterproof air pump (4), the output end of the waterproof air pump (4) is connected to the airbag (3), the top of the right side of the inner surface of the base (1) is provided with a water level sensor (5) corresponding to the position of the waterproof air pump (4), and the bottom of the cabinet (14) is provided with a PLC controller near the waterproof air pump (4). The PLC controller (6) is electrically connected to the water level sensor (5). A sliding frame (7) is provided on the rear side of the cabinet (14). A screw (10) is provided inside the sliding frame (7). A slider (11) is threaded around the screw (10). A drive frame (12) is provided on the rear side of the slider (11). Eight annular scrapers (13) are symmetrically arranged on the left and right sides of the top and bottom of the drive frame (12). Four sliding sleeves (15) are provided at the front and rear ends of the bottom of the left and right sides of the cabinet (14). A sliding rod (16) is fitted inside each of the four sliding sleeves (15). The four sliding rods (16) are slidably connected to the drive frame (12) and the annular scrapers (13). Limit rings (25) are provided at the top and bottom of each of the four sliding rods (16).
2. A weather protective enclosure for outdoor communications equipment according to claim 1, wherein: A timer motor (9) is installed on the top of the sliding frame (7). The timer motor (9) is electrically connected to the PLC controller (6). The output end of the timer motor (9) passes through the top of the sliding frame (7) and is connected to the screw (10). The other end of the screw (10) is rotatably connected to the bottom of the sliding frame (7). A rainproof cover (8) is installed on the top of the sliding frame (7).
3. A weather-resistant enclosure for outdoor communication equipment as defined in claim 1, wherein: The cabinet unit (14) has louvers (17) on the upper left and right sides, and a fan (18) is installed in the center of the lower inner surface of the cabinet unit (14).
4. A weather protective enclosure for outdoor communication equipment as defined in Claim 3, wherein: The cabinet (14) has a lampshade (21) on its inner upper surface, and a lighting lamp (24) is installed inside the lampshade (21).
5. A weather enclosure for outdoor communication equipment according to claim 4, wherein: The front surface of the cabinet unit (14) is connected to the cabinet door (19) by a hinge. A handle (20) is provided on the left end of the front surface of the cabinet door (19). A door stopper (22) is provided on the upper right corner of the rear surface of the cabinet door (19). The other end of the door stopper (22) is connected to the top of the cabinet unit (14).
6. A weather-resistant enclosure for outdoor communication equipment as defined in claim 5, wherein: The top of the cabinet (14) is provided with a drainage slope (23), and the front surface of the base (1) is provided with four drainage outlets (2).
7. A weather-resistant enclosure for outdoor communication equipment as defined in claim 1, wherein: The top of the limiting ring (25) at the lower end of the sliding rod (16) is provided with four fixing grooves (26), and the interior of each of the four fixing grooves (26) is threaded with a fixing screw (27).