A resettable thermal trigger fuse release and unlocking method

Abstract

The application discloses a resettable heat-triggered fuse release device and an unlocking method, and belongs to the technical field of locking / unlocking core components for high-end aerospace, aviation and weapon equipment. The release device comprises a shell, a pulling rod, a pulling spring, two symmetrically arranged limiting stop sheets, a fuse unlocking assembly, a magnetic attraction driving assembly and a tensioning reset adjusting assembly. Unlocking triggering is realized by fusing a non-metallic fuse wire through double-redundant heating resistors, reliable locking is realized by matching the angle of the limiting stop sheet with the angle-limiting boss structure of the pulling rod, the limiting stop sheet is smoothly unfolded by relying on the repulsive force of the magnetic attraction sheet and the component force of the pulling spring, and the tensioning degree of the fuse wire is controllable and the fuse wire is quickly reset for repeated use through the adjustable wire pressing structure. The application realizes low-impact, high-reliability and wide-environment-adaptability unlocking release, has compact and lightweight structure, is convenient to assemble and maintain, and can be widely applied to the limiting and releasing scenes of various high-end equipment, such as satellite / rocket separation, hatch unlocking, solar wing unfolding and the like.

Description

Technical Field

[0001] This invention relates to the technical field of locking / unlocking core components for high-end equipment in aerospace, aviation, and weaponry, specifically to a resettable thermally triggered fuse release device and unlocking method. Background Technology

[0002] Release mechanisms, as core locking / unlocking components, are widely used in high-end equipment fields such as aerospace, weaponry, and aviation. They undertake critical tasks such as satellite-rocket separation, hatch unlocking, warhead safety release, and solar array deployment. Their performance directly determines the success or failure of equipment missions and operational safety. As modern equipment develops towards lightweight, high reliability, and extreme environment adaptability, traditional release mechanisms can no longer meet the stringent application requirements, and technological bottlenecks are becoming increasingly prominent.

[0003] In existing technologies, traditional pyrotechnic release devices suffer from drawbacks such as complex structure and difficult assembly. Their unlocked state cannot be directly detected, requiring indirect judgment, which poses a risk of false alarms. Furthermore, the unlocking process involves significant impact and vibration, easily damaging precision instruments within the equipment. Additionally, inherent flaws in the design of the pyrotechnic agents and structure result in insufficient long-term storage stability and potential safety hazards such as malfunctions.

[0004] New thermal release devices, represented by shape memory alloy (SMA) driven types, have the advantage of low impact, but they have significant problems with poor environmental adaptability: the deformation capacity of shape memory alloys is significantly affected by the ambient temperature. The deformation capacity decreases significantly in low-temperature environments, which directly leads to insufficient pin pulling force, and the unlocking reliability cannot be guaranteed, making it difficult to adapt to the application requirements of extreme temperature environments such as aerospace.

[0005] Meanwhile, existing release devices generally suffer from problems such as non-reusability, difficulty in resetting, large structural size, and poor compatibility. During the testing phase, it is necessary to frequently replace the entire component, resulting in high usage costs and low assembly and maintenance efficiency. They cannot meet the development needs of modern equipment for lightweight, high reusability, and high adaptability. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a resettable thermally triggered fuse release device. This device solves the technical problems of existing release devices, such as large impact, low unlocking reliability, poor environmental adaptability, non-reusability, complex structure, and insufficient compatibility. It achieves unlocking and release functions with low impact, high reliability, wide environmental adaptability, quick reset and reusability, and compact and lightweight structure.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A resettable thermally triggered fuse release includes a housing, a pull rod, a pull spring, a limiting mechanism, a thermal fuse unlocking mechanism, a magnetic drive mechanism, and a tension adjustment mechanism. The pull rod is slidably installed in the inner cavity of the housing, and the pull spring is sleeved on the outer periphery of the pull rod. The two ends of the pull spring abut against the pull rod and the inner wall of the housing, respectively. The limiting mechanism includes two symmetrically hinged limiting baffles connected to the inner cavity of the outer shell. Each of the two limiting baffles has a limiting boss on its inner side. The rear end of the pull rod has a limiting step that matches the limiting boss. When the limiting boss abuts against the limiting step, the pull rod is axially limited, and the pull spring is in a compressed and stored energy state. In the locked state, the front end of the pull rod protrudes from the front end face of the outer shell. The thermal fuse unlocking mechanism includes a fuse wire, a circuit board, at least two heating resistors, and a power supply wire. The circuit board is fixed to the rear end of the inner cavity of the housing. The heating resistors are symmetrically arranged on the circuit board. The two ends of the fuse wire are respectively connected to the rear ends of the two limiting baffles. The middle section of the fuse wire is tightly fitted with the heating resistors. The power supply wire is electrically connected to the circuit board and extends to the outside of the housing. The magnetic drive mechanism includes two sets of paired magnetic plates. Each set of magnetic plates is fixed to the opposite side wall of the limiting baffle and the outer shell. The magnetic poles of the opposite surfaces of the two magnetic plates in the same set are the same, which provides a repulsive torque for the limiting baffle to rotate outward around the hinge point. The tension adjustment mechanism includes a pressure block, a pre-tightening screw, and a locking nut. The pressure block is slidably mounted on the circuit board. The pre-tightening screw passes through the back cover of the housing and abuts against the pressure block, which is used to push the pressure block to press the fuse wire to adjust its tension. The locking nut is threadedly engaged with the pre-tightening screw to lock the position of the pre-tightening screw.

[0008] Furthermore, two heating resistors are provided, and the two heating resistors are symmetrically arranged at both ends of the circuit board to form a redundant heating structure with dual backups; the two heating resistors are arranged in a series-parallel combination, and the resistance value of the heating resistors is adjusted to adapt to different power supply voltages, melting temperatures and melting times.

[0009] Furthermore, both the contact surface of the limiting boss and the contact surface of the limiting step are set as inclined surfaces, and the inclination angle of both is θ, the value of which is in the range of 0°~10°. When θ=0°, the limiting boss and the limiting step are in planar contact, and the axial force of the pull spring does not generate a radial component force that drives the limiting baffle to rotate. At this time, the spring force mainly acts on the retraction of the pull rod, and the tension force transmitted to the fuse is minimal. When θ>0°, the inclined surface decomposes part of the axial force into a radial component force, driving the limiting baffle to rotate outward, while keeping the fuse taut.

[0010] Furthermore, the inner cavity of the outer shell is provided with limiting inclined surfaces corresponding to the limiting baffles one by one. The limiting inclined surfaces are used to limit the maximum outward rotation angle of the limiting baffles. When the limiting baffles rotate to the maximum rotation angle, the magnetic attracting pieces still maintain a repulsive force on the limiting baffles to prevent the limiting baffles from rebounding. The two magnetic attracting pieces are closest and have the greatest repulsive force when the limiting baffles are in the locked position. As the limiting baffles rotate outward and unfold, the magnetic gap increases but still maintains an effective repulsive force.

[0011] Furthermore, a support plate is fixed inside the outer shell, and the circuit board is fixedly mounted on the support plate. The front end face of the support plate is used to limit and buffer the retraction stroke of the pull rod.

[0012] Furthermore, the limiting baffle is hinged to the inner cavity of the housing by a pin, and the two limiting baffles are arranged symmetrically along the central axis of the pull rod.

[0013] Furthermore, the fusion wire is made of high-strength non-metallic rope, specifically aramid fiber rope.

[0014] Furthermore, in the unlocked state, the pull rod retracts into the inner cavity of the housing under the drive of the pull spring, releasing the restriction on the external mechanism.

[0015] Furthermore, the rear cover is detachably connected to the rear end of the outer shell, and the rear cover and the outer shell are connected by a threaded connection or a snap-fit ​​connection.

[0016] The present invention also provides a method for unlocking a resettable thermally triggered fuse release, based on the above-mentioned resettable thermally triggered fuse release, comprising the following steps: S1 Locking State Maintenance: Two limit plates are tightened and bound by a fusible wire. The limit boss on the inner side of the limit plate abuts against the limit step of the pull rod, restricting the axial movement of the pull rod. The pull spring is in a compressed and stored energy state. The front end of the pull rod protrudes from the outer shell to limit the external mechanism. S2 unlock trigger: Power is supplied to the circuit board through the power supply wire, and the heating resistor converts electrical energy into heat energy, which heats the bonded fuse wire until the fuse wire reaches the temperature threshold for loss of its fracture strength and breaks, thus releasing the binding constraint on the two limit plates. S3 Limiting baffle unfolds: After the fuse breaks, the limiting baffle, under the combined action of the component of the axial force of the pull spring and the repulsive force of the paired magnetic plates, rotates and unfolds around the pin axis until it abuts against the limiting inclined surface of the outer shell. The limiting boss and the limiting step disengage, releasing the axial limitation on the pull rod. S4 Pull Rod Retraction Unlock: Driven by the pull spring, the pull rod retracts into the inner cavity of the housing, and the locking tongue at the front end of the pull rod retracts into the housing, completing the unlocking and release of the external mechanism.

[0017] The beneficial effects of this invention are as follows: This invention employs a non-metallic rope unlocking method that uses thermal melting to replace traditional pyrotechnic agents and shape memory alloys. The unlocking process is free from severe impact, preventing damage to precision instruments. Furthermore, the non-metallic melting wire has a low melting temperature and no significant heat conduction, making it unaffected by extreme ambient temperatures. This significantly improves the environmental adaptability and operational stability of the release device and solves the problems of insufficient deformation capacity and lack of pin-pulling force at low temperatures in shape memory alloy-driven devices.

[0018] This invention employs a dual-redundant symmetrical arrangement of heating resistors to form a dual-path backup heating structure. Even if a single heating resistor fails, the fuse wire can still be melted and unlocked, significantly improving unlocking reliability. At the same time, the heating resistors can be adapted to different power supply voltage requirements of satellites, rockets, etc., through series and parallel combinations and resistance value adjustment. Without adjusting the mechanical structure and external power interface, precise control of melting temperature and melting time can be achieved, demonstrating extremely strong compatibility and adaptability.

[0019] This invention achieves flexible matching of locking force and unlocking driving force through a symmetrical limiting baffle and pull rod angle-adaptive limiting boss structure: by adjusting the tilt angle θ of the limiting boss, the distribution ratio of the axial force of the pull spring to the rotational torque of the limiting baffle can be adjusted according to the pull force requirements. When θ = 0°, the axial force of the pull spring does not generate a radial component, and the spring force is mainly used for the pull rod retraction, while minimizing the force transmitted to the fuse wire, reducing the load on the fuse wire, and adapting to scenarios with large pull force and high stiffness springs; when θ > 0°, increasing the θ angle can increase the rotational driving force of the limiting baffle, ensuring smooth unlocking, while keeping the fuse wire in a taut state at all times, maintaining a continuous and tight fit with the heating resistor, further ensuring the reliability of the fuse, and adapting to scenarios with small pull force requirements.

[0020] This invention employs a dual-drive unfolding structure utilizing the repulsive force of magnetic clasps and the component force of a pull-out spring. Combined with the limiting bevel design of the outer shell, this ensures that the limiting baffle can quickly and smoothly rotate outwards after the fuse line melts, while the limiting bevel precisely controls the unfolding angle. The two magnetic clasps are closest and exert the greatest repulsive force when the limiting baffle is in the locked position, facilitating a rapid response in the initial unlocking phase. As the limiting baffle rotates outwards, the magnetic gap increases but still maintains effective repulsive force. This continuous repulsive force prevents the limiting baffle from springing back after unfolding, completely avoiding the problem of secondary jamming between the limiting boss and the limiting step, ensuring a fully controllable and fault-free unlocking process.

[0021] This invention features a detachable back cover and a tension adjustment mechanism. After unlocking, simply open the back cover to replace the fuse wire, adjust the tension of the fuse wire using the pre-tightening screw, and then lock it with the locking nut to reset the release device. This allows for reuse without replacing the entire structure, significantly reducing testing and usage costs and improving assembly and maintenance efficiency. The overall structure is compact with few parts, enabling miniaturization and lightweight design, making it suitable for various space-constrained high-end equipment installation scenarios. Attached Figure Description

[0022] Figure 1 This is a top view of a resettable thermally triggered fuse release device according to a specific embodiment of the present invention; Figure 2 This is a front view of a resettable thermally triggered fuse release device according to a specific embodiment of the present invention; Figure 3 This is a cross-sectional view of a resettable thermally triggered fuse release device according to a specific embodiment of the present invention; Figure 4 This is a rear view of the resettable thermally triggered fuse release device after removing the back cover in a specific embodiment of the present invention; Figure 5 This is a schematic diagram of the resettable thermally triggered fuse release device in the fuse-unlocked state according to a specific embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the limiting baffle in a specific embodiment of the present invention; Figure 7 This is a schematic diagram of the pull rod in a specific embodiment of the present invention.

[0023] Explanation of reference numerals in the attached drawings: 1-Pull rod, 2-Outer shell, 3-Limit stop plate, 4-Fuse wire, 5-Rear cover, 6-Preload screw, 7-Locking nut, 8-Power supply wire, 9-Pin, 10-Magnetic suction plate, 11-Pull spring, 12-Support plate, 13-Circuit board, 14-Heating resistor, 15-Filling block, 16-Limit boss, 17-Limit step, 18-Limit slope. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0025] like Figures 1 to 7 As shown, the present invention discloses a resettable thermally triggered fuse release device (thermal knife pin remover), which includes six core parts: housing 2, pull rod 1, pull spring 11, limit mechanism, thermal fuse unlocking mechanism, magnetic drive mechanism and tension adjustment mechanism.

[0026] The outer shell 2 is a hollow cylindrical shell structure made of high-strength lightweight alloy material. The front end is provided with a guide sliding hole that matches the pull rod 1, and the rear end is provided with a detachable back cover 5. The back cover 5 is connected to the outer shell 2 by threads, which makes it easy to open for replacement of the fuse wire 4 and equipment reset.

[0027] Pull rod 1 has a stepped shaft structure and is slidably installed in the inner cavity of housing 2. The front end of pull rod 1 passes through the guide slide hole at the front end of housing 2 and protrudes from the front end face of housing 2, forming a locking tongue structure for limiting the external mechanism. The middle section of pull rod 1 is provided with a spring abutment step. Pull spring 11 is sleeved on the outer periphery of pull rod 1. The front end of pull spring 11 abuts against the spring abutment step, and the rear end of pull spring 11 abuts against the inner wall at the front end of housing 2. When pull rod 1 moves backward, it compresses pull spring 11 to complete energy storage.

[0028] The limiting mechanism includes two limiting baffles 3, which are symmetrically hinged to the inner cavity of the outer shell 2 via pins 9 and arranged symmetrically along the central axis of the pull rod 1. Each of the inner front ends of the two limiting baffles 3 is integrally provided with a limiting boss 16, and the rear end of the pull rod 1 is provided with a limiting step 17 that matches the limiting boss 16. When the limiting boss 16 and the limiting step 17 abut against each other, an axial limiting structure is formed, restricting the axial movement of the pull rod 1 backward. At this time, the pull spring 11 is in a compressed and stored energy state, and the locking tongue of the pull rod 1 remains protruding, achieving stable limiting of the external mechanism.

[0029] The contact surfaces of the limiting boss 16 and the limiting step 17 are both set as inclined surfaces, with an inclination angle of θ. The value of θ ranges from 0° to 10° and can be adjusted according to the actual pulling force load requirements. When θ = 0°, the limiting boss 16 and the limiting step 17 are in planar contact, and the axial force of the pulling spring 11 does not generate a radial component force that drives the limiting baffle 3 to rotate. At this time, the spring force mainly acts on the retraction of the pulling rod 1, and the tension force transmitted to the fuse wire 4 is minimal. This maximizes the use of the spring force to achieve the retraction action of the pulling rod 1, making it suitable for application scenarios with large pulling force and high stiffness springs. When θ is set to 5° or 10°, the axial force of the pull spring 11 is decomposed into a radial component through the inclined surface, and the torque transmitted to the limit plate 3 rotating around the pin shaft 9 increases, which can accelerate the rotation and unfolding of the limit plate 3, adapting to the application scenarios of small pull force and small stiffness spring, while ensuring that the fuse wire 4 is always in a taut state and tightly attached to the heating resistor 14.

[0030] The thermal fuse unlocking mechanism includes a fuse wire 4, a circuit board 13, two heating resistors 14, and a power supply wire 8. A support plate 12 is fixed to the rear end of the inner cavity of the outer casing 2. The circuit board 13 is fixed to the rear end face of the support plate 12 with screws. The front end face of the support plate 12 faces the rear end of the pull rod 1, limiting and buffering the retraction stroke of the pull rod 1 to prevent collision between the pull rod 1 and the circuit board 13. The two heating resistors 14 are symmetrically welded and fixed to both ends of the circuit board 13, forming a redundant heating structure with dual backups. Both ends of the fuse wire 4 are respectively bound and fixed to the rear ends of the two limiting baffles 3. The middle section of the fuse wire 4 laterally wraps around the heating surfaces of the two heating resistors 14, tightly fitting against them. One end of the power supply wire 8 is electrically connected to the power supply circuit of the circuit board 13, and the other end extends through the rear cover 5 to the outside of the outer casing 2 for connection to an external power supply system.

[0031] The two heating resistors 14 can be arranged in series or parallel as needed. By adjusting the resistance value of the heating resistors 14, they can be adapted to different power supply voltage requirements of satellites, rocket launch vehicles, etc. At the same time, the resistance value can be adjusted according to the material and thickness of the fuse wire 4 to match the corresponding fusing current, so as to achieve precise control of fusing temperature and fusing time. There is no need to adjust the mechanical structure and external power interface, making it highly adaptable. In this embodiment, the fuse wire 4 is made of high-strength non-metallic rope such as aramid fiber rope (such as Kevlar rope). Non-metallic ropes have good flexibility and unrestricted bending radius, which can adapt to different binding and limiting structures. At the same time, the fusing temperature is lower, there is no significant heat conduction, heat is easily accumulated, the fusing release efficiency is higher, and the unlocking process is shock-free.

[0032] The magnetic drive mechanism includes two sets of paired magnetic plates 10. Each set of magnetic plates 10 includes two permanent magnets with the same pole facing each other. One permanent magnet is fixed to the outer wall of the limiting stop 3, and the other permanent magnet is fixed to the inner wall of the outer shell 2 opposite to the limiting stop 3. The magnetic poles of the two magnetic plates 10 in the same set are the same, and they always generate a repulsive force, providing a continuous repulsive torque for the limiting stop 3 to rotate outward around the pin 9. The two magnetic plates 10 are closest and have the greatest repulsive force when the limiting stop 3 is in the locked position, which is conducive to a rapid response in the initial unlocking stage. As the limiting stop 3 rotates outward and unfolds, the magnetic gap increases but still maintains an effective repulsive force, continuously preventing the limiting stop 3 from rebounding. Meanwhile, the inner cavity of the outer shell 2 is provided with limiting inclined surfaces 18 that correspond one-to-one with the limiting baffles 3. The limiting inclined surfaces 18 are set on the rotation path of the limiting baffles 3. When the limiting baffles 3 rotate outward to the maximum angle, its side wall abuts against the limiting inclined surfaces 18 to achieve precise limitation of the unfolding angle. At this time, the magnetic suction piece 10 still maintains the repulsive force on the limiting baffles 3, which can effectively prevent the limiting baffles 3 from rebounding and avoid secondary jamming between the limiting protrusions 16 and the limiting steps 17, ensuring reliable unlocking.

[0033] The tension adjustment mechanism includes a pressure block 15, a pre-tightening screw 6, and a locking nut 7. The pressure block 15 is slidably mounted in the middle of the circuit board 13, located between the two heating resistors 14. The pre-tightening screw 6 passes through the rear cover 5 axially, with its front end abutting against the rear end face of the pressure block 15. Rotating the pre-tightening screw 6 pushes the pressure block 15 forward, pressing the middle section of the fusible wire 4, thereby adjusting the overall tension of the fusible wire 4 and maintaining a stable and predictable tension state, ensuring a tight fit with the heating resistors 14. The locking nut 7 is threadedly engaged with the pre-tightening screw 6 on the outer side of the rear cover 5. Tightening the locking nut 7 locks the pre-tightening screw 6 in its current position, preventing it from loosening due to vibration or other reasons, and ensuring the long-term stability of the locked state.

[0034] The complete working process of the resettable thermally triggered fuse release in this embodiment is as follows: Locked state: Pull the pull rod 1 outward to compress the pull spring 11 to the stored state. Rotate the two limiting plates 3 inward so that the limiting boss 16 on the inner side of the limiting plate 3 abuts against the limiting step 17 at the rear end of the pull rod 1. The rear ends of the two limiting plates 3 are tightened and bound by the fuse 4, preventing the limiting plates 3 from rotating outward around the pin 9 and maintaining the axial limit of the pull rod 1. Rotate the preload screw 6 to push the pressure block 15 to press the fuse 4. Adjust the fuse 4 to the preset tension and tighten the locking nut 7 to lock the preload screw 6, completing the locking assembly. At this time, the locking tongue at the front end of the pull rod 1 protrudes from the outer shell 2, achieving stable limiting of the external mechanism.

[0035] Unlocking process: An external power supply is connected via power supply wire 8. Circuit board 13 supplies power to two heating resistors 14. Heating resistors 14 convert electrical energy into heat energy, which accumulates continuously. When the temperature exceeds the breaking strength threshold of the fuse wire 4, the fuse wire 4 breaks at the heating resistor 14, releasing the binding constraint on the rear ends of the two limiting baffles 3. After the fuse wire 4 breaks, the limiting baffles 3, under the combined action of the radial component of the axial force of the pull spring 11 and the repulsive force of the paired magnetic plates 10, rapidly rotate and unfold outward around the pin shaft 9 until they abut against the limiting inclined surface 18 of the outer shell 2, completing the unfolding action. At the same time as the limiting baffles 3 unfold, the limiting boss 16 on its inner side completely disengages from the limiting step 17 of the pull rod 1, releasing the axial constraint on the pull rod 1. Driven by the pull spring 11, the pull rod 1 quickly retracts into the inner cavity of the outer shell 2, and the locking tongue at the front end of the pull rod 1 completely retracts into the inner shell 2, releasing the limiting constraint on the external mechanism and completing the low-impact, high-reliability unlocking and release.

[0036] Reset process: After unlocking, unscrew the back cover 5, loosen the locking nut 7 and the pre-tightening screw 6, replace the new fuse wire 4, reconnect both ends of the fuse wire 4 to the rear ends of the two limit plates 3, pull the pull rod 1 outward, rotate the limit plate 3 so that the limit boss 16 abuts against the limit step 17, adjust the fuse wire 4 to the target tension using the pre-tightening screw 6, tighten the locking nut 7 to lock, and reinstall the back cover 5 to complete the overall reset of the release device and enable reuse.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. For example, the fuse wire 4 can be replaced by a high-strength rope made of various non-metallic materials, the hinge connection between the limiting baffle 3 and the outer shell 2 can be replaced by a hinge connection instead of a pin hinge, and the number of heating resistors 14 can be set to 3 or more as needed. These are all alternative solutions and within the scope of protection of the present invention.

Claims

1. A resettable thermally triggered fuse release device, characterized in that, Includes housing, pull rod, pull spring, limit mechanism, thermal fuse unlocking mechanism, magnetic drive mechanism and tension adjustment mechanism; The pull rod is slidably installed in the inner cavity of the housing, and the pull spring is sleeved on the outer periphery of the pull rod. The two ends of the pull spring abut against the pull rod and the inner wall of the housing, respectively. The limiting mechanism includes two sets of limiting baffles symmetrically hinged to the inner cavity of the outer shell. Each set of limiting baffles has a limiting boss on its inner side. The rear end of the pull rod has a limiting step that matches the limiting boss. When the limiting boss abuts against the limiting step, the pull rod is axially limited and the pull spring is in a compressed and stored energy state. The thermal fuse unlocking mechanism includes a fuse wire, a circuit board, at least two heating resistors, and a power supply wire. The circuit board is fixed to the rear end of the inner cavity of the housing. The heating resistors are symmetrically arranged on the circuit board. The two ends of the fuse wire are respectively connected to the rear ends of the two sets of limiting baffles. The middle section of the fuse wire is tightly fitted with the heating resistors. The power supply wire is electrically connected to the circuit board and extends to the outside of the housing. The magnetic drive mechanism includes two sets of paired magnetic plates. Each set of magnetic plates is fixed to the opposite side wall of the limiting baffle and the outer shell. The magnetic poles of the opposite surfaces of the two magnetic plates in the same set are the same, which provides a repulsive torque for the limiting baffle to rotate outward around the hinge point. The tension adjustment mechanism includes a pressure block, a pre-tightening screw, and a locking nut. The pressure block is slidably mounted on the circuit board. The pre-tightening screw passes through the back cover of the housing and abuts against the pressure block, which is used to push the pressure block to press the fuse wire to adjust its tension. The locking nut is threadedly engaged with the pre-tightening screw to lock the position of the pre-tightening screw.

2. The resettable thermally triggered fuse release device according to claim 1, characterized in that, The heating resistor is configured as two, and the two heating resistors are symmetrically arranged at both ends of the circuit board to form a redundant heating structure with dual backups; the two heating resistors are arranged in a series-parallel combination, and the resistance value of the heating resistors is adjusted to adapt to different power supply voltages, fusing temperatures and fusing times.

3. The resettable thermally triggered fuse release device according to claim 1, characterized in that, The contact surfaces of the limiting boss and the limiting step are both set as inclined surfaces, and the inclination angle of both is θ, the value of which is in the range of 0° to 10°. When θ = 0°, the limiting boss and the limiting step are in planar contact. When θ > 0°, the inclined surface is used to decompose the axial force of the pull spring into a radial component that drives the limiting baffle to rotate outward.

4. The resettable thermally triggered fuse release device according to claim 1, characterized in that, The inner cavity of the outer shell is provided with limiting inclined surfaces that correspond one-to-one with the limiting baffles. The limiting inclined surfaces are used to limit the maximum outward rotation angle of the limiting baffles. When the limiting baffles rotate to the maximum rotation angle, the magnetic attracting plate still maintains a repulsive force on the limiting baffles to prevent the limiting baffles from rebounding.

5. The resettable thermally triggered fuse release device according to claim 1, characterized in that, The inner cavity of the outer shell is also fixed with a support plate, and the circuit board is fixedly installed on the support plate. The front end face of the support plate is used to limit and buffer the retraction stroke of the pull rod.

6. The resettable thermally triggered fuse release device according to claim 1, characterized in that, The limiting baffle is hinged to the inner cavity of the outer shell by a pin, and the two sets of limiting baffles are arranged symmetrically along the central axis of the pull rod.

7. The resettable thermally triggered fuse release device according to claim 1, characterized in that, The fuse is made of high-strength non-metallic rope, specifically Kevlar rope.

8. The resettable thermally triggered fuse release device according to claim 1, characterized in that, The front end of the pull rod protrudes from the front face of the housing, forming a locking tongue structure for limiting the external mechanism; in the unlocked state, the pull rod retracts into the inner cavity of the housing under the drive of the pull spring, releasing the limitation on the external mechanism.

9. The resettable thermally triggered fuse release device according to claim 1, characterized in that, The rear cover is detachably connected to the rear end of the outer shell, and the rear cover and the outer shell are connected by a threaded connection or a snap-fit ​​connection.

10. A method for unlocking a resettable thermally triggered fuse release, characterized in that, Based on the resettable thermally triggered fuse release device according to any one of claims 1-9, the implementation includes the following steps: S1 Locking State Maintenance: Two sets of limit plates are tightened and bound by a fusible wire. The limit boss on the inner side of the limit plate abuts against the limit step of the pull rod, restricting the axial movement of the pull rod. The pull spring is in a compressed and stored energy state. The front end of the pull rod protrudes from the outer shell to limit the external mechanism. S2 unlock trigger: Power is supplied to the circuit board through the power supply wire, and the heating resistor converts electrical energy into heat energy, which heats the attached fuse wire until the temperature of the fuse wire exceeds its melting temperature and melts, thus releasing the binding constraint on the two sets of limit plates. S3 Limiting baffle unfolds: After the fuse wire melts, the limiting baffle, under the combined action of the component of the axial force of the pull spring and the repulsive force of the paired magnetic plates, rotates and unfolds around the pin axis until it abuts against the limiting inclined surface of the outer shell. The limiting boss and the limiting step disengage, releasing the axial limitation on the pull rod. S4 Pull Rod Retraction Unlock: Driven by the pull spring, the pull rod retracts into the inner cavity of the housing, and the locking tongue at the front end of the pull rod retracts into the housing, completing the unlocking and release of the external mechanism.

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