A high-voltage drop-out type fuse

Abstract

This invention relates to the field of high-voltage protection device technology, specifically a high-voltage drop-out fuse. It has a contact seat on its upper side, a return spring between the contact seat and the lower stationary contact, and an arc-extinguishing fuse tube with a built-in fuse wire below the stationary contact. A shape memory metal sheet is located at the top of the upper moving contact inside the first vent at the upper end of the arc-extinguishing fuse tube. At room temperature, the edge of this metal sheet adheres to the first vent, and the edge deforms upwards when the fuse wire heats up. A second vent is located at the lower end of the arc-extinguishing fuse tube, and a first telescopic block is installed on its side, extending into the lower contact assembly. During normal operation, the return spring provides stable contact pressure, and the shape memory metal sheet seals the vent and continuously tensions the fuse tube, resisting external interference and reducing the probability of non-faulty accidental drop-out. In case of a fault, the shape memory metal sheet actively pushes open the upper stationary contact, coordinating with bidirectional arc extinguishing and simultaneous unlocking at the lower end, thus solving the problem of traditional fuse tubes refusing to drop-out.

Description

Technical Field

[0001] This invention relates to the field of high-voltage protection devices, specifically a high-voltage drop-out fuse. Background Technology

[0002] As the most crucial short-circuit and overload protection device on the distribution transformer side, the high-voltage drop-out fuse's structural design directly determines the reliability of fault circuit interruption and the continuity of power supply. Currently, most high-voltage drop-out fuses on the market rely on the fuse wire inside the fuse tube to carry the rated operating current. When a short circuit or overload fault occurs in the line, the fuse wire melts rapidly under the action of a large current, and the fuse tube then drops rapidly around its lower shaft due to its own gravity, forming a clearly visible disconnection gap. This achieves physical isolation of the faulty circuit, facilitating maintenance personnel to quickly locate and handle the fault. Traditional structures use a single-sided clamping upper contact assembly. The metal fixing block on one side of the upper moving contact is embedded in the groove of the upper stationary contact. The conductive connection is achieved by the lateral clamping force provided by the outer spring. When there are burrs, oxide layers, or dust and oil stains on the contact surface, a lateral static friction force far exceeding the design value will be generated. When this friction force is greater than the weight of the fuse tube itself, the fuse tube cannot fall normally after the fuse melts, causing the fault circuit to remain energized. This can easily lead to serious accidents such as circuit burnout and transformer explosion. Moreover, the fault is highly concealed and difficult to detect during routine inspections.

[0003] To address the aforementioned problems, existing technologies offer several solutions. For example, patent application CN201921070977.5 discloses a drop-out fuse, which proposes the following solution: The traditional single-sided clamping contact is replaced with a multi-point contact structure with a vertical spherical surface at the top. Two to three contact ball sockets are machined on the upper stationary contact, and the same number of contact balls are correspondingly arranged on the upper moving contact. Each ball socket is independently equipped with a contact spring to provide vertically downward contact pressure. This solution eliminates the lateral friction of the traditional structure, fundamentally solving the problem of the fuse tube failing to drop. Simultaneously, the multi-point contact increases the... The total conductive area effectively distributes the current, reducing the current-carrying load of a single contact and extending the contact's service life. However, this solution has certain limitations in practical use: when operating in complex environments, it cannot withstand external interference such as bird strikes and wind and rain disturbances. When the equipment is installed in the outdoor power distribution tower for a long time, birds perching and pecking, wind shaking, and rain washing can easily cause the upper moving contact and the ball socket to loosen abnormally, causing the fuse tube to fall off without failure, resulting in unexplained power outages and interruptions in power supply. This not only affects the normal power consumption of users but also significantly increases the workload of maintenance personnel in inspection and power restoration. Summary of the Invention

[0004] The purpose of this invention is to provide a high-voltage drop-out fuse to solve the problem of the fuse tube failing to drop normally, and at the same time to solve the problem of non-faulty accidental drop caused by the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A high-voltage drop-out fuse includes an insulator, a contact seat on the upper side of the insulator, an upper stationary contact on the lower end of the contact seat, a return spring between the contact seat and the upper stationary contact, an arc-extinguishing fuse tube on the lower side of the upper stationary contact, a fuse wire inside the arc-extinguishing fuse tube, a first vent on the upper end of the arc-extinguishing fuse tube, an upper moving contact inside the first vent, and a shape memory metal sheet on the upper end of the upper moving contact. The edge of the shape memory metal sheet is in contact with the edge of the first vent at room temperature. The lower end of the shape memory metal sheet is fixedly connected to the fuse wire. Heating the fuse wire causes the edge of the shape memory metal sheet to deform upwards. A second vent on the lower end of the arc-extinguishing fuse tube, a lower contact assembly on the lower end of the second vent, a first telescopic block installed on the lower side of the arc-extinguishing fuse tube, and the other end of the fuse wire connected to the lower contact assembly through the second vent. The first telescopic block extends into the lower contact assembly.

[0006] A return spring is installed between the contact seat and the upper stationary contact at the upper end of the insulator. A shape memory metal sheet is installed at the upper moving contact inside the first outlet at the upper end of the arc-extinguishing fuse tube. The edge of the shape memory metal sheet is in contact with the first outlet at room temperature, and the lower end is fixedly connected to the fuse wire. The edge can deform upward as the fuse wire heats up. A second outlet is provided at the lower end of the arc-extinguishing fuse tube, and a first telescopic block extending into the lower contact assembly of the lower stationary contact is installed on its lower side. At the same time, the two ends of the fuse wire are respectively connected to the lower end of the shape memory metal sheet and the lower contact assembly. The return spring can be the upper stationary contact. It provides stable vertical contact pressure, ensuring reliable conductive connection between the upper stationary contact and the upper moving contact under normal operating conditions. Simultaneously, it buffers external vibrations and impacts. The shape memory metal sheet seals the first vent at room temperature, effectively preventing dust and rainwater from entering the arc-extinguishing fuse tube, thus avoiding environmental impact on fuse performance. Furthermore, during normal load operation, the shape memory metal sheet undergoes a slight upward deformation due to the operating temperature generated by the fuse current. This deformation is insufficient to open the first vent, but it continuously applies upward tension to the upper end of the arc-extinguishing fuse tube, gradually increasing the installation tightness over time. This effectively counteracts contact wear and fuse creep-induced loosening. Combined with the vertical contact pressure applied by the return spring, it significantly enhances the connection strength of the upper contact assembly, resisting external interference such as bird strikes and wind and rain disturbances, greatly reducing the probability of non-faulty accidental drop of the arc-extinguishing fuse tube, ensuring power continuity. In case of a fault, during the fuse's heating and melting process, the heated edge of the shape memory metal sheet deforms significantly upward, quickly opening the first vent and forming a bidirectional exhaust channel with the lower second vent, greatly improving the extinguishing efficiency. The arc gas discharge efficiency is improved, and the arc extinguishing is accelerated. It can also actively push open the upper stationary contact through the upward thrust generated by deformation, overcoming the lateral static friction caused by burrs, oxide layers, and dust and oil stains on the contact surface. This fundamentally solves the hidden danger of the arc-extinguishing fuse tube refusing to fall after the fuse blows. The first telescopic block extends into the structure of the lower contact assembly, which not only achieves stable connection and precise positioning between the arc-extinguishing fuse tube and the lower contact assembly during normal operation, but also provides reliable hinge support and movement guidance for the arc-extinguishing fuse tube in case of failure and fall, ensuring that its fall process is smooth and stable.

[0007] Preferably, the lower contact assembly includes a lower moving contact and a lower stationary contact. The lower moving contact is located below the second air outlet. A lower stationary contact is located below the lower moving contact. The end of the lower stationary contact away from the lower moving contact is fixedly installed on the lower side of the insulator. A mounting groove is provided on the side of the lower stationary contact opposite to the lower moving contact. The lower moving contact includes a pressure section and an actuation section. The pressure section and the actuation section are connected in an L-shape. Rotating pins are provided on both sides of the connection between the pressure section and the actuation section. The lower moving contact rotates in the mounting groove through the rotating pins. The arc-extinguishing air pressure of the second air outlet acts on the pressure section. The first telescopic block is connected to the actuation section.

[0008] By designing the lower contact assembly as a separate structure of the lower moving contact and the lower stationary contact, the lower moving contact is positioned below the second air outlet, with the lower stationary contact correspondingly positioned below it. The end of the lower stationary contact furthest from the lower moving contact is fixedly installed on the lower side of the insulator. A mounting groove is formed on the side opposite to the lower stationary and lower moving contacts. The lower moving contact is designed with an L-shaped connection between the pressure section and the actuation section. Rotating pins are provided on both sides of the connection between the pressure section and the actuation section, allowing the lower moving contact to rotate within the mounting groove. This allows the arc-extinguishing gas pressure from the second air outlet to directly act on the pressure section of the lower moving contact, extending... The first telescopic block entering the lower contact assembly connects to the actuating section of the lower moving contact. The L-shaped split-rotating structure converts the arc-extinguishing gas pressure impact force ejected from the second outlet during a fault into a rotational torque of the lower moving contact around the rotating pin. This achieves self-powered operation without an external power source, utilizing the energy generated by the fault itself to drive the unlocking action. By leveraging the lever principle, the force of the arc-extinguishing gas pressure is amplified, significantly improving the reliability and response speed of the lower moving contact driving the first telescopic block to complete the unlocking process. This avoids unlocking failure due to insufficient gas pressure. The support design of the double-sided rotating pins ensures the stability of the lower moving contact's rotation process, effectively preventing... The design addresses issues of jamming and wobbling. The mounting slot provides precise rotational limits for the lower moving contact, ensuring its travel and angle. The split structure allows for individual component replacement in case of damage, significantly reducing maintenance costs. Combined with the heating mechanism of the shape memory metal sheet actively opening the upper stationary contact, a dual unlocking system is constructed, eliminating the jamming risk associated with single-end unlocking. This solves the problem of the arc-extinguishing tube failing to fall after the fuse wire melts in traditional fuses. Furthermore, the design reuses the second air outlet pressure generated by the bidirectional arc-extinguishing structure as the power source for unlocking the lower contact, achieving efficient utilization of arc-extinguishing energy. Without the need for additional drive devices, the hinged support structure formed after the lower contact drives the first telescopic block to unlock, combined with the buffering effect of the return spring and the active opening action of the memory metal sheet, ensures the smooth and stable drop of the arc-extinguishing fuse tube. In addition, during normal operation, the stable clamping of the first telescopic block by the lower contact, together with the continuous tension of the memory metal sheet and the vertical contact pressure of the return spring, forms a coordinated fastening system, further enhancing the installation firmness of the arc-extinguishing fuse tube and greatly improving its ability to resist external interference such as bird strikes and wind and rain disturbances, and to prevent non-faulty accidental drops.

[0009] Preferably, an installation sleeve is provided on the lower side of the arc-extinguishing fuse tube, and a first telescopic channel is provided on the side of the execution section opposite to the arc-extinguishing fuse tube. A first magnet is provided at the end of the first telescopic channel away from the arc-extinguishing fuse tube. One end of the first telescopic block moves left and right within the first telescopic channel, and the end of the first telescopic block extending out of the first telescopic channel is hinged to the installation sleeve. A pressure hole is provided at the position corresponding to the second air outlet in the pressure section. A pressure chamber is provided in the pressure hole, and the pressure chamber connects the pressure hole and the first telescopic channel. An air supply pipe is provided between the pressure hole and the second air outlet, and the air supply pipe is made of plastic.

[0010] An installation sleeve is installed on the lower side of the arc-extinguishing fuse tube. A first telescopic channel is opened on the side of the execution section opposite to the arc-extinguishing fuse tube. A first magnet is installed at the end of the first telescopic channel away from the arc-extinguishing fuse tube, allowing one end of the first telescopic block to move left and right within the first telescopic channel. The end of the first telescopic block extending out of the first telescopic channel is hinged to the installation sleeve. Simultaneously, a pressure hole is opened at the position corresponding to the second air outlet in the pressure section. A pressure chamber is set in the pressure hole, connecting the pressure hole and the first telescopic channel. A plastic gas supply pipe is installed between the pressure hole and the second air outlet. The plastic gas supply pipe can accurately guide the arc-extinguishing gas pressure generated at the second air outlet into the pressure chamber. The energy generated by the fault itself drives the first telescopic block to complete the unlocking action. This system operates without requiring an additional power source, featuring a simple and low-cost structure. The pressure chamber acts as a pressure buffer and pressurization space, stabilizing air pressure output and preventing instantaneous air pressure fluctuations from causing delays or failures in the unlocking action. This significantly improves the stability and reliability of the unlocking response. During normal operation, the first magnet stably attracts the first telescopic block, keeping it extended and forming a reliable hinge with the mounting sleeve. This provides a stable connection and positioning for the lower end of the arc-extinguishing fuse tube. Simultaneously, the magnetic attraction force effectively counteracts the loosening effects caused by external vibrations and wind swaying, further enhancing the installation's firmness. The hinge structure between the first telescopic block and the mounting sleeve can directly serve as the rotation fulcrum for the arc-extinguishing fuse tube's fall after unlocking, ensuring a precise and unbiased drop trajectory. To avoid problems such as jamming and impact damage, the plastic gas supply pipe automatically melts and breaks under the high temperature of the fault arc, which can promptly cut off the gas pressure path and prevent the continuous leakage of arc-extinguishing gas from affecting subsequent operation and maintenance. Moreover, the plastic material has good insulation properties and will not cause the risk of conductive short circuit. The overall structure organically combines magnetic positioning and gas pressure drive, realizing a precise switch between firm locking during normal operation and rapid unlocking during faults. The unlocking action is crisp and clean, without intermediate jamming. The core execution and power transmission structure of the L-shaped lower moving contact lever unlocking mechanism is that the arc-extinguishing gas pressure acting on the pressure section is converted into linear driving force in the first telescopic channel through the gas supply pipe and pressure chamber, replacing the simple reliance on the lower The indirect transmission method, in which the moving contact rotates to drive the first telescopic block, significantly improves the response speed and force accuracy of the unlocking action of the first telescopic block. At the same time, the magnetic locking of the first magnet and the stable clamping of the L-shaped lower moving contact form a double lower-end locking system, further enhancing the installation firmness of the lower end of the arc-extinguishing fuse tube and effectively preventing non-faulty accidental drops. The hinge structure between the first telescopic block and the mounting sleeve, together with the smooth rotation design of the double-sided rotating pins, ensures the smooth and stable drop process of the arc-extinguishing fuse tube, avoiding jamming, swaying, or impact damage. In addition, the air pressure buffering effect of the pressure chamber can also offset the instantaneous impact force when the L-shaped lower moving contact rotates, extending the service life of the lower moving contact and the rotating pin.

[0011] Preferably, a second telescopic channel is provided on the upper side of the execution section, the second telescopic channel is connected to the pressure chamber, a second telescopic block is provided in the second telescopic channel, a locking block is provided on the side of the second telescopic block facing the arc-extinguishing fuse tube, a connecting block is provided on the upper end of the mounting sleeve, a triangular locking groove is provided on the connecting block, and the connecting block cooperates with the locking block through the triangular locking groove.

[0012] By setting a second telescopic channel connecting the pressure chamber on the upper side of the execution section, and installing a second telescopic block inside the second telescopic channel, a locking block is set on the side of the second telescopic block facing the arc-extinguishing fuse tube. Simultaneously, a connecting block with a triangular groove is set on the upper end of the sleeve installed at the lower end of the arc-extinguishing fuse tube. The connecting block engages with the locking block through the triangular groove. During normal operation, the locking block embeds into the triangular groove to form a rigid locking connection, effectively eliminating gaps at the hinge, reducing vibration and noise during operation, and minimizing component wear. It can also withstand greater axial and radial loads, significantly improving the connection strength at the lower end of the arc-extinguishing fuse tube. The inclined guide structure of the triangular groove also enables automatic centering and locking during installation, eliminating the need for precise alignment and significantly reducing the difficulty of on-site installation and commissioning. In case of failure, the arc-extinguishing air pressure in the pressure chamber can synchronously drive the second telescopic block to retract upwards, causing the locking block to quickly disengage from the triangular groove, completing a secondary unlocking action at the lower end. The unlocking response is fast and decisive, with no risk of jamming. Combined with other unlocking mechanisms, it can further enhance the overall performance. To ensure reliable unlocking, the arc-extinguishing air pressure in the pressure chamber is directly reused as the power source, achieving multi-level efficient utilization of arc-extinguishing energy. This, combined with the linear unlocking action of the first telescopic block, forms a dual-point synchronous unlocking mechanism at the lower end, avoiding the problem of failure of a single unlocking mechanism leading to rejection of the fuse. Simultaneously, the rigid locking of the locking block and the triangular slot, along with the magnetic locking of the first magnet and the stable clamping of the L-shaped lower moving contact, constitute a triple lower-end fastening system, further enhancing the overall installation firmness of the arc-extinguishing fuse tube and significantly improving its ability to resist external interference such as bird strikes and wind and rain disturbances, effectively reducing the probability of non-faulty accidental drops. Furthermore, the air pressure buffering effect of the pressure chamber also applies to the second telescopic block, stabilizing its extension speed and preventing instantaneous air pressure impacts from damaging the mating surface of the locking block and the triangular slot, extending the service life of the components. The design of both blocks sharing the same pressure chamber ensures a high degree of synchronization between the unlocking actions of the first and second telescopic blocks, avoiding jamming or stuck problems caused by time differences in action.

[0013] Preferably, a hook is provided on the side of the second telescopic block opposite to the locking block. The hook includes a fixed section and a hook head section, which are connected in an L-shape. A hook plate is provided on the upper side of the lower stationary contact head. When the hook is installed normally, the hook head section and the hook plate cooperate.

[0014] By setting a hook on the side opposite to the locking block of the second telescopic block, the hook is composed of a fixed section and a hook head section connected in an L-shape. A hook plate is correspondingly set on the upper side of the lower stationary contact. During normal installation, the hook head section and the hook plate cooperate with each other. During normal operation, the rigid engagement of the hook head section and the hook plate forms an additional axial anti-disengagement lock, which can withstand greater axial tensile force and impact load, eliminating the risk of upward movement and loosening of the arc-extinguishing fuse tube caused by external impact. At the same time, it can effectively limit the abnormal retraction of the second telescopic block, prevent the locking block from accidentally disengaging from the triangular slot, and ensure the long-term reliability of the locking structure. In case of failure, the second telescopic block retracts upward under the pressure of the pressure chamber, while driving the hook to move synchronously, so that the hook head section automatically disengages from the hook plate to complete the unlocking. No additional power source is required. The unlocking action and the action of the locking block disengaging from the triangular slot are completely synchronized with each other, with no time difference, avoiding the arc-extinguishing fuse tube jamming caused by local locking residue. To prevent falls, the power source driving the second telescopic block through the pressure chamber achieves a triple unlocking action at the lower end: the first telescopic block retracts, the locking block disengages from the triangular slot, and the hook disengages from the hook plate. This significantly improves the overall unlocking efficiency and reliability. Simultaneously, the rigid engagement of the locking block and the triangular slot, the magnetic locking of the first magnet, and the stable clamping of the L-shaped lower moving contact together constitute a four-fold lower-end fastening system, forming a progressively enhanced protection against accidental falls. This system can withstand stronger external interference such as bird strikes and strong winds and rain, further reducing the probability of non-malfunction accidental falls. Furthermore, the cooperation between the hook and the hook plate can precisely limit the extension and retraction of the second telescopic block, preventing excessive retraction that could damage the pressure chamber sealing structure and extending the service life of the components. The rigid cooperation of both also counteracts the vibration of the second telescopic block during operation, reducing wear on the mating surfaces of the locking block and the triangular slot, and improving the durability of the locking structure.

[0015] Preferably, a torsion spring is provided between the hook section and the fixed section. One end of the torsion spring acts on the fixed section, and the other end acts on the hook section. The torsion spring can be compressed towards one side of the arc-extinguishing fuse tube.

[0016] By installing a torsion spring between the hook section and the fixed section, with one end of the torsion spring acting on the fixed section and the other end acting on the hook section, and compressing it towards the arc-extinguishing fuse tube, the hook section is pushed towards the hook plate during installation. After the hook section contacts the hook plate, the torsion spring is compressed towards the arc-extinguishing fuse tube under the pressure. Once the hook section has successfully passed the hook plate and completed the assembly, the torsion spring releases its elastic potential energy to automatically reset the hook section to the locking position that matches the hook plate. This achieves automatic engagement between the hook and the hook plate, eliminating the need for manual manipulation of the hook section. This significantly simplifies the on-site installation of high-voltage drop-out fuses, reduces installation difficulty, and avoids the problem of component deformation and damage caused by rigid hooks forcibly aligning the installation. Furthermore, it provides a continuous and stable preload force to the hook section after installation, eliminating the clearance between the hook section and the hook plate and reducing the need for additional preload. To mitigate the risks of component wear and loosening due to vibration during operation, and to effectively prevent accidental disengagement when the hook head is subjected to minor external disturbances such as bird strikes or wind swaying, the torsion spring design provides crucial installation adaptability and pre-tightening support for the rigid hook locking structure. This not only compensates for the inconvenience of installing a purely rigid hook, but also further enhances the axial anti-disengagement locking effect, ensuring that the hook will not detach from the hook plate due to vibration or external disturbances during normal operation. At the same time, in case of failure, it will not hinder the second telescopic block from synchronously retracting and unlocking the hook. It complements the hook engagement structure, together improving the axial anti-disengagement link in the lower four-fold fastening system, further enhancing the installation firmness of the arc-extinguishing fuse tube and its ability to resist external interference. It also ensures the synchronicity and reliability of the unlocking action, avoiding the problem of the arc-extinguishing fuse tube refusing to fall.

[0017] Preferably, the hook section has a first conical surface on the side opposite to the insulator, and the hook plate has a second conical surface on the side opposite to the arc-extinguishing fuse tube, and the taper of the first conical surface and the second conical surface are both 1:2.

[0018] By setting a first conical surface on the side of the hook section opposite to the insulator and a second conical surface on the side of the hook plate opposite to the arc-extinguishing fuse tube, and setting the taper of both the first and second conical surfaces to 1:2, the first and second conical surfaces will form a sloped guiding fit when the arc-extinguishing fuse tube is installed and the hook section is pushed towards the hook plate. This automatically converts the axial thrust into a lateral force on the hook section towards the arc-extinguishing fuse tube, guiding the hook section to retract smoothly and avoid the impact. This eliminates the need for manual adjustment and significantly reduces the difficulty of on-site installation of high-voltage drop-out fuses. It also avoids the problems of deformation, jamming, and component damage caused by rigid collisions on pure planes. The 1:2 taper ratio precisely balances smooth guiding and self-locking stability after engagement, ensuring smooth and jam-free retraction. This design not only prevents the hook section from slipping and loosening laterally due to external interference such as vibration, bird strikes, or wind swaying during normal operation, but also overcomes the inherent defects of pure planar hook structures, such as difficulty in installation alignment, easy jamming, and large fitting gaps. It further enhances the axial anti-loosening locking effect. At the same time, the conical torsion spring reset structure forms a synergistic effect. The conical guide combined with the elastic reset force of the torsion spring allows the hook section to reset more accurately and smoothly to the locked position after passing the hook plate, improving installation efficiency and locking accuracy. In case of failure, it will not hinder the second telescopic block from driving the hook to retract upward synchronously to unlock, ensuring the synchronicity and smoothness of the unlocking action. This further improves the installation firmness of the arc-extinguishing fuse tube and its ability to resist external interference, and also avoids the problem of the arc-extinguishing fuse tube refusing to fall due to unlocking jamming.

[0019] Preferably, a guide hole is provided on the side of the pressure hole away from the pressure chamber, and the guide hole is used to fix the fuse.

[0020] By creating a guide hole on the side of the pressure orifice away from the pressure chamber and using it to fix the fuse, this positioning and fixing design can accurately guide the fuse through the pressure section of the lower moving contact and achieve reliable fixing. This prevents the fuse from getting tangled, loosening, or rubbing against metal parts during assembly and long-term outdoor operation, ensuring that the fuse is always under the designed tension and can quickly melt at the predetermined position in case of failure. Furthermore, integrating the fuse fixing point on one side of the pressure orifice inlet prevents the fuse from blocking the pressure orifice during assembly, ensuring unobstructed airflow throughout the pneumatic transmission path, and eliminating the need for an additional independent fuse. The fixed component simplifies the overall structure of the lower contact assembly, reduces the number of parts, and the guide hole provides key fuse positioning for the pneumatic transmission system, reducing potential defects such as easy fuse displacement and easy blockage of the transmission path. It significantly improves the pneumatic utilization efficiency of the gas supply pipe and pressure chamber, ensures that the first telescopic block can obtain sufficient and stable driving force to complete the unlocking action, ensures stable conductive connection of the fuse and firm installation of the arc-extinguishing fuse tube during normal operation, and ensures rapid response and reliable execution of the pneumatic unlocking action in case of failure. It fundamentally avoids the problem of the arc-extinguishing fuse tube failing to fall due to fuse loosening, insufficient air pressure, or blockage of the transmission path.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The design employs a dual unlocking system, combining the upper memory metal sheet and reset spring, with a lower L-shaped lower moving contact lever structure and pneumatic drive for triple synchronous unlocking. This system, along with a bidirectional air-outlet arc-extinguishing structure, allows the memory metal sheet to deform significantly upon heating during a fault, actively opening the upper stationary contact. This overcomes the lateral static friction caused by burrs and oxide layers on the contact surface. Simultaneously, the air pressure from the second outlet is amplified by the lever, driving the first and second telescopic blocks to retract synchronously, completing the triple unlocking at the lower end. The system utilizes the fault's own energy for self-powered operation, eliminating the risk of jamming during single-end unlocking. This fundamentally solves the problem of traditional fuses where the arc-extinguishing fuse tube fails to fall after the fuse wire melts, significantly improving the reliability of fault circuit disconnection.

[0022] 2. The fastening system design, which combines the vertical contact pressure of the upper return spring with the continuous tension of the memory metal sheet, the magnetic attraction of the lower first magnet, the clamping of the L-shaped lower moving contact, the locking of the triangular slot of the locking block, and the axial anti-dislodgement of the hook plate, with the torsion spring pre-tightened to the 2-conical guide fit structure, can eliminate the gaps between the mating surfaces during normal operation, offset the loosening of the connection caused by contact wear and fuse creep, effectively resist external interference such as bird strikes and strong winds and rain, greatly reduce the probability of non-faulty accidental drop of the arc extinguishing fuse tube, ensure power supply continuity, and reduce the workload of operation and maintenance inspection and power restoration.

[0023] 3. Through the design of guide holes, plastic insulated gas supply pipes, lower contact assemblies, and multiple guide and positioning structures, the guide holes simultaneously achieve precise fixation of the fuse and protection of the gas pressure path, avoiding fuse misalignment, entanglement, and pressure hole blockage. The plastic gas supply pipes are self-breaking at high temperatures and are insulated and safe. The triangular slots and conical guide structures simplify on-site installation and alignment. The split components are easy to replace individually, eliminating the need for additional independent fixing and driving components, reducing the number of parts, lowering production and maintenance costs, and improving the long-term stability and service life of the equipment. Attached Figure Description

[0024] Figure 1 This is a front view of the high-voltage drop-out fuse of the present invention; Figure 2 This is a top view of the high-voltage drop-out fuse of the present invention; Figure 3 for Figure 2 A sectional view of AA in the diagram; Figure 4 for Figure 3 Enlarged view of point B in the middle; Figure 5 for Figure 3 Enlarged view of point C in the middle; Figure 6 This is a schematic diagram of the high-voltage drop-out fuse of the present invention; Figure 7 for Figure 6 Enlarged view of point D in the middle.

[0025] In the diagram: 1. Insulator; 101. Contact seat; 102. Upper stationary contact; 103. Return spring; 2. Arc-extinguishing fuse; 201. Fuse wire; 202. First air outlet; 203. Upper moving contact; 204. Memory metal sheet; 205. Second air outlet; 206. First telescopic block; 207. Mounting sleeve; 208. Connecting block; 209. Triangular slot; 3. Lower moving contact; 301. Lower stationary contact; 302. Mounting groove; 303. Pressure section; 304. Execution section; 305. Rotating pin; 306. First telescopic channel; 307. First magnet; 308. Pressure hole; 309. Pressure chamber; 4. Air supply pipe; 5. Second telescopic channel; 501. Second telescopic block; 502. Locking block; 6. Hook; 601. Fixing section; 602. Hook head section; 603. First conical surface; 604. Second conical surface; 7. Hook plate; 8. Torsion spring; 9. Guide hole. Detailed Implementation

[0026] Please see Figures 1 to 7 This invention provides a high-voltage drop-out fuse, the technical solution of which is as follows: For details, please refer to Figures 1 to 7A high-voltage drop-out fuse includes an insulator 1. A contact seat 101 is located on the upper side of the insulator 1. An upper stationary contact 102 is located at the lower end of the contact seat 101. A return spring 103 is located between the contact seat 101 and the upper stationary contact 102. An arc-extinguishing fuse tube 2 is located below the upper stationary contact 102. A fuse wire 201 is installed inside the arc-extinguishing fuse tube 2. A first vent 202 is located at the upper end of the arc-extinguishing fuse tube 2. An upper moving contact 203 is located inside the first vent 202, and a shape memory metal sheet 204 is located at the upper end of the upper moving contact 203. The edge of the shape memory metal sheet 204 is in contact with the edge of the first vent 202 at room temperature. The lower end of the shape memory metal sheet 204 is fixedly connected to the fuse wire 201. The center of the bottom of the shape memory metal sheet 204 is welded to the fuse wire 201 for arc extinguishing. When the temperature of the fuse tube 2 does not exceed 80°C, the shape memory metal sheet 204 only undergoes a deformation of 0.1mm. The heating of the fuse wire 201 causes the edge of the shape memory metal sheet 204 to deform upwards. When the arc-extinguishing fuse tube 2 triggers the high-temperature arc extinguishing process, the temperature rises to over 240°C, and the shape memory metal sheet 204 is completely deformed, resulting in an axial deformation of 2mm. A second vent 205 is provided at the lower end of the arc-extinguishing fuse tube 2, and a lower contact assembly is provided at the lower end of the second vent 205. The other end of the fuse wire 201 is connected to the lower contact assembly through the second vent 205. The first telescopic block 206 extends into the lower contact assembly. The lower contact assembly includes a lower moving contact 3 and a lower stationary contact 301. The lower moving contact 3 is located below the second vent 205, and the lower stationary contact 301 is located below the lower moving contact 3. The end of the head 301 away from the lower moving contact 3 is fixedly installed on the lower side of the insulator 1. A mounting groove 302 is provided on the side of the lower stationary contact 301 opposite to the lower moving contact 3. The lower moving contact 3 includes a pressure section 303 and an execution section 304, which are connected in an L-shape. A mounting sleeve 207 is provided on the lower side of the arc-extinguishing fuse tube 2. A connecting block 208 is provided on the upper end of the mounting sleeve 207, and a triangular groove 209 is provided on the connecting block 208. A first telescopic block 206 is installed on the lower side of the arc-extinguishing fuse tube 2. A first telescopic channel 306 is provided on the side of the execution section 304 opposite to the arc-extinguishing fuse tube 2. A first magnet 307 is provided at the end of the first telescopic channel 306 away from the arc-extinguishing fuse tube 2. One end of the first telescopic block 206 is located in the first telescopic channel 306. When the first telescopic block 206 moves left and right within the channel 306 and a short circuit occurs, the first telescopic block 206 extends to its maximum extent. At this time, the end of the first telescopic block 206 inside the first telescopic channel 306 is locked at the channel opening to maintain connection, and the end of the first telescopic block 206 extending out of the first telescopic channel 306 is hinged to the mounting sleeve 207. Rotating pins 305 are provided on both sides of the connection between the pressure section 303 and the execution section 304. The lower moving contact 3 rotates in the mounting groove 302 through the rotating pins 305. The arc-extinguishing gas pressure of the second air outlet 205 acts on the pressure section 303. The first telescopic block 206 is connected to the execution section 304. Pressure holes 308 are provided at the positions corresponding to the pressure section 303 and the second air outlet 205. An air supply pipe 4 is provided between the pressure hole 308 and the second air outlet 205.The gas supply pipe 4 is made of plastic and is inserted into the second gas outlet 205. A guide hole 9 is provided on the side of the pressure hole 308 away from the pressure chamber 309. The guide hole 9 is used to fix the fuse 201, which is pressed into the guide hole 9. A pressure chamber 309 is provided inside the pressure hole 308, connecting the pressure hole 308 to the first telescopic channel 306. A second telescopic channel 5 is provided on the upper side of the execution section 304, connecting the pressure chamber 309. Sealing rings are provided in both the first telescopic channel 306 and the second telescopic channel 5 to prevent air pressure leakage and ensure the telescopic block can be driven. A second telescopic block 501 is provided inside the second telescopic channel 5. A locking block 502 is provided on the side of the second telescopic block 501 facing the arc-extinguishing fuse 2. The connecting block 208 passes through the triangular locking groove 2. In conjunction with the locking block 502, the second telescopic block 501 has a hook 6 on the side opposite to the locking block 502. The hook 6 includes a fixed section 601 and a hook head section 602, which are connected in an L-shape. A torsion spring 8 is provided between the hook head section 602 and the fixed section 601. One end of the torsion spring 8 acts on the fixed section 601, and the other end acts on the hook head section 602. The torsion spring 8 can be compressed towards one side of the arc-extinguishing fuse tube 2. A hook plate 7 is provided on the upper side of the lower stationary contact 301. The side of the hook head section 602 opposite to the insulator 1 has a first conical surface 603, and the side of the hook plate 7 opposite to the arc-extinguishing fuse tube 2 has a second conical surface 604. The taper of both the first conical surface 603 and the second conical surface 604 is 1:2. During normal installation, the hook head section 602 and the hook plate 7 cooperate.

[0027] Working principle: Please refer to Figures 1 to 7During normal operation of the high-voltage drop-out fuse, the arc-extinguishing fuse tube 2 is installed below the upper stationary contact 102 at the upper end of the insulator 1. The return spring 103 applies a stable vertical contact pressure to the upper stationary contact 102, making the upper stationary contact 102 and the upper moving contact 203 at the upper end of the arc-extinguishing fuse tube 2 fit tightly together, achieving a reliable conductive connection. The shape memory metal sheet 204 at the first outlet 202 at the upper end of the arc-extinguishing fuse tube 2 is sealed to the first outlet 202 at room temperature, and its lower end is fixedly connected to the fuse wire 201, continuously applying tension to the upper end of the arc-extinguishing fuse tube 2. The lower end of the arc-extinguishing fuse tube 2 is hinged to the first telescopic block 206 through the mounting sleeve 207. The first telescopic block 206 extends into the first telescopic channel 306 of the lower moving contact 3, and is stably attracted and protected by the first magnet 307. With the first telescopic block 206 fixed in a fixed state, the locking block 502 on the second telescopic block 501 is embedded in the triangular locking groove 209 of the upper connecting block 208 of the mounting sleeve 207 to form a rigid locking connection. The locking hook 6 on the outside of the second telescopic block 501, under the pre-tightening of the torsion spring 8 and the cooperation of the 1:2 conical surface guide, stably hooks the hook head section 602 with the hook plate 7 on the lower stationary contact 301. The lower end of the fuse 201 is precisely fixed through the guide hole 9 and connected to the lower contact assembly. The whole structure forms a quadruple fastening structure of upper end spring compression and memory metal sheet 204 tension, lower end magnetic attraction, locking, and hooking. It can resist external interference such as bird touch and wind and rain disturbance, and prevent the arc extinguishing fuse tube 2 from falling off without failure. When the circuit has an overload or short circuit fault, the fuse 201 heats up and melts quickly. The metal plate 204 deforms significantly upwards upon heating, actively pushing open the upper stationary contact 102 and opening the first air outlet 202. High-pressure arc-extinguishing gas is generated inside the arc-extinguishing fuse tube 2, and is discharged bidirectionally from the upper first air outlet 202 and the lower second air outlet 205 to achieve rapid arc extinguishing. The arc-extinguishing gas pressure ejected from the second air outlet 205 is introduced into the pressure hole 308 and pressure chamber 309 through the plastic gas supply pipe 4. The gas pressure in the pressure chamber 309 synchronously drives the first telescopic block 206 to retract and detach from the first magnet 307, and the second telescopic block 501 to move upward, driving the locking block 502 to exit the triangular locking groove 209. The locking hook 6 retracts synchronously, causing the hook head section 602 to detach from the hook plate 7 from above, completing the triple synchronous unlocking at the lower end. The L-shaped lower moving contact 3 rotates around the rotating pin 305 under the action of gas pressure, and enters... The unlocking force is amplified in one step. The upper memory metal sheet 204 actively pushes open, and the lower multi-pressure unlocking action is synchronized. The arc-extinguishing fuse tube 2 loses its upper and lower locking support and falls quickly and steadily around the lower hinge point under its own gravity, forming a clear disconnection gap, realizing the rapid and reliable disconnection of the faulty circuit. After the fault is cleared, a new arc-extinguishing fuse tube 2 is reinstalled and pushed upward to reset. The first conical surface 603 of the hook 6 cooperates with the second conical surface 604 of the hook plate 7 for guidance. The hook head section 602 compresses the torsion spring 8 to avoid it. After passing the hook plate 7, the torsion spring 8 automatically resets and hooks. The locking block 502 automatically engages with the triangular locking slot 209. The first telescopic block 206 is re-attracted and locked by the first magnet 307. The upper memory metal sheet 204 returns to its room temperature contact state.The reset spring 103 re-presses the upper stationary contact 102, restoring the fuse to normal operation and allowing it to be put back into protective function.

[0028] The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.

Claims

1. A high-voltage drop-out type fuse, comprising an insulator (1), the upper end side of the insulator (1) is provided with a contact seat (101), the lower end of the contact seat (101) is provided with an upper static contact (102), the contact seat (101) and the upper static contact (102) are provided with a reset spring (103), the lower side of the upper static contact (102) is provided with an arc-extinguishing fuse tube (2), and the arc-extinguishing fuse tube (2) is provided with a fuse (201) inside, characterized in that, The arc-extinguishing fuse tube (2) is provided with a first air outlet (202) at its upper end. An upper moving contact (203) is provided inside the first air outlet (202), and a memory metal sheet (204) is provided at the upper end of the upper moving contact (203). The edge of the memory metal sheet (204) is in contact with the edge of the first air outlet (202) at room temperature. The lower end of the memory metal sheet (204) is fixedly connected to the fuse (201). The heating of the fuse (201) causes the edge of the memory metal sheet (204) to deform upward. The arc-extinguishing fuse tube (2) is provided with a second air outlet (205) at its lower end. A lower contact assembly is provided at the lower end of the second air outlet (205). A first telescopic block (206) is installed on the side of the lower end of the arc-extinguishing fuse tube (2). The other end of the fuse (201) is connected to the lower contact assembly through the second air outlet (205). The first telescopic block (206) extends into the lower contact assembly. The lower contact assembly includes a lower moving contact (3) and a lower stationary contact (301). The lower moving contact (3) is located below the second air outlet (205). The lower stationary contact (301) is located below the lower moving contact (3). The end of the lower stationary contact (301) away from the lower moving contact (3) is fixedly installed on the lower side of the insulator (1). A mounting groove (302) is provided on the side of the lower stationary contact (301) opposite to the lower moving contact (3). The lower moving contact (3) includes a pressure... The pressure section (303) and the execution section (304) are connected in an L-shape. Rotating pins (305) are provided on both sides of the connection between the pressure section (303) and the execution section (304). The lower moving contact (3) rotates in the mounting groove (302) through the rotating pins (305). The arc-extinguishing gas pressure of the second air outlet (205) acts on the pressure section (303). The first telescopic block (206) is connected to the execution section (304). An installation sleeve (207) is provided on the lower side of the arc-extinguishing fuse tube (2). A first telescopic channel (306) is provided on the side of the execution section (304) opposite to the arc-extinguishing fuse tube (2). A first magnet (307) is provided at the end of the first telescopic channel (306) away from the arc-extinguishing fuse tube (2). One end of the first telescopic block (206) moves left and right in the first telescopic channel (306), and the end of the first telescopic block (206) extending out of the first telescopic channel (306) is hinged to the installation sleeve (207). A pressure hole (308) is provided at the position corresponding to the second air outlet (205) of the pressure section (303). A pressure chamber (309) is provided in the pressure hole (308). The pressure chamber (309) connects the pressure hole (308) and the first telescopic channel (306). A gas supply pipe (4) is provided between the pressure hole (308) and the second air outlet (205).

2. The high-voltage drop-out fuse according to claim 1, characterized in that, The execution section (304) is provided with a second telescopic channel (5) on its upper side. The second telescopic channel (5) is connected to the pressure chamber (309). The second telescopic channel (5) is provided with a second telescopic block (501). The side of the second telescopic block (501) facing the arc-extinguishing fuse tube (2) is provided with a locking block (502). The upper end of the mounting sleeve (207) is provided with a connecting block (208). The connecting block (208) is provided with a triangular slot (209). The connecting block (208) cooperates with the locking block (502) through the triangular slot (209).

3. A high-voltage drop-out fuse according to claim 2, characterized in that, The second telescopic block (501) is provided with a hook (6) on the side opposite to the locking block (502). The hook (6) includes a fixed section (601) and a hook head section (602). The fixed section (601) and the hook head section (602) are connected in an L-shape. A hook plate (7) is provided on the upper side of the lower stationary contact (301). When the hook (6) is installed normally, the hook head section (602) cooperates with the hook plate (7).

4. A high-voltage drop-out fuse according to claim 3, characterized in that, A torsion spring (8) is provided between the hook section (602) and the fixed section (601). One end of the torsion spring (8) acts on the fixed section (601) and the other end acts on the hook section (602). The torsion spring (8) can be compressed toward one side of the arc-extinguishing melting tube (2).

5. A high-voltage drop-out fuse according to claim 3, characterized in that, The hook section (602) has a first conical surface (603) on the side opposite to the insulator (1), and the hook plate (7) has a second conical surface (604) on the side opposite to the arc-extinguishing fuse tube (2), and the taper of the first conical surface (603) and the second conical surface (604) is 1:

2.

6. A high-voltage drop-out fuse according to claim 1, characterized in that, A guide hole (9) is provided on the side of the pressure hole (308) away from the pressure chamber (309), and the guide hole (9) is used to fix the fuse (201).

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