Limiting latch device driven by shape memory effect

Abstract

The invention relates to the field of aircraft structures and latch structures, and provides a shape memory effect driven limiting latch device which comprises a first SMA wire, a driving module, a locking module, a reset module, a fixing module and a pin shaft. The first SMA wire material shrinks when being electrified and heated, and drives the driving module to move; the driving module pushes the pin shaft to extend from an initial position to a full stroke position through mechanical transmission; the locking module is used for locking the position of the pin shaft when the pin shaft extends to the full-stroke position; the reset module is used for opening the locking state of the locking module and driving the pin shaft to return to the initial position from the full stroke position. The fixing module is used for bearing the pin shaft, the first SMA wire, the driving module, the locking module and the resetting module. The shape memory effect of SMA is fully utilized, structure simplification and performance improvement are achieved, and a new design thought is provided for an aircraft latch system.

Description

Technical Field

[0001] The present invention relates to the fields of aircraft structures and latch structures, and in particular to a position-limiting latch device driven by a shape memory effect. Background Art

[0002] Shape memory alloys (SMAs) are smart materials with unique shape memory effects and superelasticity. When heated, SMAs undergo a phase transition, generating deformation and force, making them useful as actuators. NiTi-based alloys are among the most commonly used SMA materials, and their phase transition temperature and properties can be controlled by adjusting their composition and heat treatment processes.

[0003] Currently, SMA actuators are being used in the aerospace field, primarily for vibration reduction and large deformation recovery. Some research institutions have developed SMA-based vibration isolators and dampers. Furthermore, SMAs are being used to design adaptive structures, leveraging their ability to fully recover from large deformations.

[0004] Traditional aircraft folding wingtip latches typically use hydraulic or electric actuators, which present complex structures, heavy weight, and low reliability. SMA actuators, on the other hand, offer advantages such as simple structure, light weight, and a high power-to-weight ratio, but they have not yet been used in aircraft latch systems. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a shape memory effect driven position limiting latch device, which is particularly suitable for aircraft latch systems.

[0006] The present invention adopts the following technical solutions:

[0007] A shape memory effect driven position limiting latch device includes a first SMA wire, a driving module, a locking module, a resetting module, a fixing module and a pin;

[0008] The first SMA wire contracts when electrically heated, thereby driving the driving module to move;

[0009] The driving module pushes the pin shaft from the initial position to the full stroke position through mechanical transmission;

[0010] The locking module is used to lock the position of the pin shaft when the pin shaft extends to the full stroke position;

[0011] The reset module is used to release the locking state of the locking module and drive the pin shaft to return to the initial position from the full stroke position;

[0012] The fixing module is used to carry the pin, the first SMA wire, the driving module, the locking module and the resetting module.

[0013] According to any of the possible implementations described above, an implementation is further provided, wherein the first SMA wire is formed into several strands through a pulley group, the pulley group includes a movable pulley and a fixed pulley; the fixed pulley is arranged at the end of the fixed module, and the movable pulley is arranged on the driving module; both ends of the first SMA wire are fixed to the end of the fixed module; when the first SMA wire is electrically heated and contracts, it drives the movable pulley, and then drives the driving module to move toward the end of the fixed module.

[0014] As for any possible implementation described above, an implementation is further provided, wherein the pulley assembly includes 1 fixed pulley and 2 movable pulleys, or 2 fixed pulleys and 3 movable pulleys, or 3 fixed pulleys and 4 movable pulleys.

[0015] The pulley assembly configuration is selected based on load requirements, space constraints, and specific technical requirements for drive displacement and motion accuracy. Two optimized configurations are possible: one is to connect multiple drive modules in series, effectively increasing the pin's reach to meet longer travel requirements; the other is to connect multiple drive modules in parallel, significantly increasing the overall driving force to meet the driving force requirements under higher load conditions. This flexible combination ensures that the device can adapt to the complex requirements of wingtips of different sizes, ensuring versatility and practicality.

[0016] According to any of the possible implementations described above, there is further provided an implementation, wherein the pin includes a pin end portion and a flat plate portion adjacent to the pin tail end portion, and the flat plate portion at the pin tail end portion is provided with two cross-structured sliding grooves perpendicular to the direction of movement of the pin;

[0017] The driving module includes a sliding portion and a cross structure;

[0018] The sliding part is slidably connected to the fixed module and slides along the extension and contraction direction of the pin shaft; the movable pulley is arranged on the sliding part;

[0019] The cross structure includes two sheet-like parts or rod-like parts, one end of each of the two sheet-like parts or rod-like parts is respectively arranged on the sliding part, and the other end is respectively arranged in the two sliding grooves of the cross structure;

[0020] When the first SMA wire is energized and heated to shrink, the driving module slides toward the end of the fixing module, driving the two sheet-like parts or rod-like parts of the cross-shaped structure to slide in the sliding groove of the cross-shaped structure, thereby driving the pin shaft to move in the extending direction, and the extending direction of the pin shaft is opposite to the sliding direction of the driving module.

[0021] As for any possible implementation described above, an implementation is further provided, wherein the locking module is a limit block, and the pin shaft is provided with a buckle adapted to the shape of the limit block. When the pin shaft reaches the full stroke, the limit block cooperates with the buckle to achieve limit locking of the pin shaft.

[0022] According to any possible implementation described above, there is further provided an implementation, wherein the reset module includes a second SMA wire, a rocker arm, a reset spring, and a spring positioning column;

[0023] The second SMA wire is electrically heated and contracted, and the rocker arm is driven to rotate through mechanical transmission, so that the limit block is disengaged from the buckle, and the pin shaft is released from the limit locking state;

[0024] One end of the spring positioning column is fixed to the end of the fixing module, and the other end is a free end; the reset spring is sleeved on the spring positioning column, one end of the reset spring is against the end of the fixing module, and the other end is against the driving module to provide a reset force for the driving module.

[0025] According to any possible implementation described above, there is further provided an implementation, wherein the reset module includes a second SMA wire, a rocker arm, and a third SMA wire;

[0026] The second SMA wire is electrically heated and contracted, and the rocker arm is driven to rotate through mechanical transmission, so that the limit block is disengaged from the buckle, and the pin shaft is released from the limit locking state;

[0027] The third SMA wire contracts when it is energized and heated, and drives the driving module to reset through mechanical transmission.

[0028] In any of the possible implementations described above, a further implementation is provided, wherein the first SMA wire is a nickel-iron-based shape memory alloy wire having a Ni mass fraction in the range of 50%-60%, and is trained to achieve an austenite transition temperature of 80°C-130°C. This is suitable for the operating environment and requirements of the device. To reduce complexity, the SMA wires in the device are selected to have the same composition and specifications (outer diameter), but different compositions (phase transition temperatures) and wire outer diameters (driving loads) may also be selected based on actual needs.

[0029] According to any of the possible implementations described above, an implementation is further provided, wherein the first SMA wire is a nickel-iron-based memory alloy wire having a Ni mass fraction of 54.8% and an austenite phase transition temperature of 100° C.-107° C.

[0030] As for any possible implementation manner described above, there is further provided an implementation manner, wherein the first SMA wire is replaced by a shape memory polymer SMP wire.

[0031] The beneficial effects of the present invention are as follows: existing aircraft latch systems usually rely on complex mechanical devices or hydraulic systems, and have problems such as large size, heavy weight, and low energy efficiency. The device of the present invention uses SMA wire or SMP wire as the driving force of the drive module, and converts it into the telescopic movement of the pin through clever mechanical transmission, thereby simplifying the device structure, reducing weight, and improving performance; the latch device is simple, lightweight, and efficient; the stroke of this device can be increased by 38%, and the weight can be reduced by 33.2%, which greatly improves performance; and it is suitable for aircraft wing folding. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 FIG2 is a schematic diagram showing the structural arrangement of a position limiting latch device driven by a shape memory effect according to an embodiment of the present invention.

[0033] Figure 2 FIG. 1 shows a first SMA wire arrangement diagram in an embodiment.

[0034] Figure 3 The figure shows a schematic diagram of the matching structure of the driving module and the pin shaft in the embodiment.

[0035] Figure 4 Shown is a schematic diagram of the pin structure in the embodiment.

[0036] Figure 5 FIG. 1 is a schematic diagram of a reset module in an embodiment.

[0037] Figure 6 Shown is a schematic diagram of the fixed module structure in the embodiment.

[0038] In the figure: 1-first SMA wire; 2-pin; 3-cross structure; 4-cross structure sliding groove; 5-movable pulley; 6-fixed pulley; 7-sliding part; 8-limiting block; 9-spring positioning column; 10-fixing module; 101-end of the fixing module; 21-pin end; 22-flat portion at the tail end of the pin. DETAILED DESCRIPTION

[0039] The following will describe in detail specific embodiments of the present invention with reference to the accompanying drawings. It should be noted that the technical features or combinations of technical features described in the following embodiments should not be considered isolated, and they can be combined with each other to achieve better technical effects.

[0040] like Figures 1-4 As shown, an embodiment of the present invention provides a shape memory effect driven position limiting latch device, comprising a first SMA wire 1, a driving module, a locking module, a resetting module, a fixing module and a pin 2;

[0041] The first SMA wire 1 contracts when heated by electricity, driving the driving module to move;

[0042] The driving module pushes the pin 2 from the initial position to the full stroke position through mechanical transmission;

[0043] The locking module is used to lock the position of the pin shaft 2 when the pin shaft 2 extends to the full stroke position;

[0044] The reset module is used to unlock the locking module and drive the pin 2 to return to the initial position from the full stroke position;

[0045] The fixing module is used to carry the pin 2, the first SMA wire 1, the driving module, the locking module and the resetting module.

[0046] In a specific embodiment, the device of the present invention can adopt a layered modular design, such as Figure 1 As shown, the second layer is arranged with the driving module and the pin shaft, the third layer is arranged with the fixing module, and the first layer can be reserved for expansion functions, or the first layer can be cancelled to achieve a more flexible space layout.

[0047] In a specific embodiment, the first SMA wire 1 is formed into several strands through a pulley group, and the pulley group includes a movable pulley 5 and a fixed pulley 6; the fixed pulley 6 is arranged at the end 101 of the fixing module 10, and the movable pulley 5 is arranged on the driving module; both ends of the first SMA wire 1 are fixed to the end of the fixing module 10; when the first SMA wire 1 is electrically heated and contracts, it drives the movable pulley 5, and then drives the driving module to move toward the end 101 of the fixing module.

[0048] In a specific embodiment, the pulley assembly includes one fixed pulley 6 and two movable pulleys 5. Figure 2 or 2 fixed pulleys 6 and 3 movable pulleys 5, or 3 fixed pulleys 6 and 4 movable pulleys 5.

[0049] The pulley assembly configuration is selected based on load requirements, space constraints, and the required drive displacement and accuracy. Depending on the stroke and load requirements, two or more drive modules can be connected in series to increase reach, while parallel drive modules can be used to increase drive force, achieving design requirements that cannot be met by a single drive module.

[0050] In a specific embodiment, Figure 4 As shown, the pin 2 includes a pin end 21 and a pin tail flat portion 22 adjacent thereto, and the pin tail flat portion 22 is provided with two cross-structure sliding grooves 4 perpendicular to the movement direction of the pin 2;

[0051] The driving module includes a sliding portion 7 and a cross structure 3, such as Figure 3 As shown;

[0052] The sliding portion 7 is slidably connected to the fixing module 10 and slides along the extension direction of the pin 2; the movable pulley 5 is provided on the sliding portion 7;

[0053] The cross structure 3 includes two sheet-like parts or rod-like parts, one end of each of the two sheet-like parts or rod-like parts is respectively arranged on the sliding part 7, and the other end is respectively arranged in the two cross structure sliding grooves 4;

[0054] When the first SMA wire 1 is energized, heated, and contracted, the driving module slides toward the end direction 101 of the fixing module, driving the two sheet-like portions or rod-like portions of the cross structure 3 to slide in the cross structure sliding groove 4, thereby driving the pin shaft 2 to move in the extending direction. The extending direction of the pin shaft 2 is opposite to the sliding direction of the driving module.

[0055] In a specific embodiment, Figure 5 As shown, the locking module is a limit block 8, and the pin shaft 2 is provided with a buckle adapted to the shape of the limit block 8. When the pin shaft 2 reaches the full stroke, the limit block 8 cooperates with the buckle to achieve the limit locking of the pin shaft 2.

[0056] The reset module can be implemented in various forms, for example:

[0057] In a specific embodiment, the reset module includes a second SMA wire, a rocker arm, a reset spring and a spring positioning column 9;

[0058] The second SMA wire is electrically heated and contracted, and the rocker arm is driven to rotate through mechanical transmission, so that the limit block 8 is disengaged from the buckle, and the pin shaft 2 is released from the limit locking state;

[0059] like Figure 5 As shown, one end of the spring positioning column 8 is fixed to the end 101 of the fixing module, and the other end is a free end; the reset spring is sleeved on the spring positioning column 8, and one end of the reset spring is against the end 101 of the fixing module, and the other end is against the driving module to provide a reset force for the driving module.

[0060] In another specific embodiment, the reset module includes a second SMA wire, a rocker arm, and a third SMA wire;

[0061] The second SMA wire is electrically heated and contracted, and the rocker arm is driven to rotate through mechanical transmission, so that the limit block 8 is disengaged from the buckle, and the pin shaft 2 is released from the limit locking state;

[0062] The third SMA wire contracts when it is energized and heated, and drives the driving module to reset through mechanical transmission.

[0063] In a specific embodiment, the first SMA wire 1 is a nickel-iron-based memory alloy wire with a Ni mass fraction content of 50%-60%, and an austenite phase transition temperature of 80° C.-130° C. is achieved through training.

[0064] In a specific embodiment, the fixing unit is as follows Figure 6 As shown, it is used to carry the pin 2, the first SMA wire 1, the driving module, the locking module and the reset module.

[0065] Preferably, in a specific embodiment, a nickel-iron-based memory alloy wire with a Ni mass fraction of 54.8% is selected, which has an excellent phase change temperature range (100° C.-107° C.) and is particularly suitable for the working environment and requirements of the device.

[0066] In order to reduce complexity, the SMA wires in the device are selected to have the same composition and the same specifications (outer diameter), but different compositions (phase change temperatures) and wire outer diameters (driving loads) can also be selected according to actual needs.

[0067] In a specific embodiment, the first SMA wire 1 can be replaced by a shape memory polymer SMP wire.

[0068] The second SMA wire and the third SMA wire can be selected and processed in the same manner as the first SMA wire 1 .

[0069] The working principles of the components of the above embodiment of the present invention are as follows:

[0070] The first SMA wire 1 is the main driving element of the device of the present invention and is responsible for providing the driving force to push the pin 2 out. When the first SMA wire 1 is energized, it heats up and undergoes a phase transformation from martensite to austenite, causing its length to shrink. This contraction force is transmitted to the drive module through the mechanical transmission structure.

[0071] Pulley block: The first SMA wire 1 is formed into several strands through the pulley block to provide stronger power for the drive module; the fixed pulley 6 is set at the end 101 of the fixed module, and the movable pulley 5 is set on the drive module; both ends of the first SMA wire 1 are fixed to the end 101 of the fixed module; the effect of this unique design is that when the first SMA wire 1 contracts, it drives the movable pulley 5 and simultaneously drives the drive module closer to the end 101 of the fixed module.

[0072] Driving module: One end of the two sheet-like parts or rod-like parts of the cross-cross structure 3 is respectively arranged on the sliding part 7 of the driving module, and the other end is respectively arranged in the two cross-cross structure sliding grooves 4 of the flat plate part 22 at the tail end of the pin shaft; the effect of this design is: when the driving module approaches the end 101 of the fixed module, the sheet-like part or rod-like part slides toward the far end in the sliding groove 4 (perpendicular to the direction of movement of the pin shaft and away from the center line), and through the transmission of the cross-cross structure 3, the pin shaft 2 moves in the extending direction (opposite to the direction of movement of the driving module).

[0073] The use of the cross structure 3 solves the problem of small shrinkage deformation of the first SMA wire 1, amplifies the extension displacement of the pin 2, and meets various practical application requirements.

[0074] Locking module: When the pin 2 extends to its full stroke, the limit block 8 engages the buckle and the pin 2 is locked. At this time, the first SMA wire 1 is powered off and the pin 2 remains in the full stroke position.

[0075] Reset module: When the pin shaft 2 needs to be reset, the second SMA wire is electrically heated and phase-changed to shrink, and the rocker arm is rotated through the mechanical transmission, so that the limit block 8 is disengaged from the buckle, and the pin shaft 2 is released from the limit locking state; the reset spring provides a reset force to restore the drive module to its initial position.

[0076] The return spring may also be replaced by a third SMA wire, so that the third SMA wire directly provides the restoring force of the driving module.

[0077] The pin 2 extends or retracts to realize the limiting function of the folding wingtip.

[0078] In practical applications, the pin 2 has two states:

[0079] Extended State: When pin 2 needs to be extended, power is applied to heat the first SMA wire 1, causing it to undergo a martensite-to-austenite phase transformation. This shortens the wire and generates a contraction force. This force pushes pin 2 out (the specific transmission process is: wire shortens - drive module moves toward fixed module end 101 - pin 2 moves in the extension direction), ultimately locking pin 2 via stopper 8. After power is removed from the first SMA wire 1, due to the properties of shape memory alloy, pin 2 remains in the extended state, and stopper 8 locks pin 2.

[0080] Retracted: When pin 2 needs to be retracted, power is applied to heat the second SMA wire, causing it to undergo a phase change and shorten. This drives the rocker arm to rotate, releasing the latch. Pin 2 returns to its original position under the action of the return spring. After power is removed from the second SMA wire, pin 2 remains in the retracted position until the next operation.

[0081] In the above embodiment, the first SMA wire 1 , the second SMA wire, and the third SMA wire are all driven by direct current.

[0082] The first SMA wire 1 , the second SMA wire, and the third SMA wire in the embodiment of the present invention can all be replaced by shape memory polymer (SMP) wires, which may have a slower response speed but can still achieve the basic locking function.

[0083] In actual use, low voltage driving can be used to reduce heat generation.

[0084] The present invention fully utilizes the shape memory effect of SMA, achieves structural simplification and performance improvement, and provides a new design idea for aircraft latch systems.

[0085] This invention aims to address the complex structure, heavy weight, low reliability, and high power supply voltage issues currently associated with aircraft folding wingtip locking devices. It proposes a novel position-limiting latch device based on the shape memory alloy (SMA) effect. This device features a compact structure, lightweight, high reliability, and suitability for low-voltage environments. It is particularly well-suited for applications where wingtip space is limited and weight-sensitive, helping to improve overall aircraft performance. Compared to existing technologies, the present invention demonstrates significant innovation and advancement in the following aspects:

[0086] (1) An innovative mechanical transmission mechanism is proposed, namely a driving design composed of a pulley set, a cross structure 3 and a sliding guide groove 4, which overcomes the problem that the original SMA driver has insufficient output displacement and cannot meet the actual engineering requirements of the wingtip latch. The present invention effectively achieves the amplification of the output displacement of the SMA wire. Experimental results show that the actual stroke of the device reaches 9.66mm, and the driving force reaches 50N. In addition, compared with the traditional electromagnetic drive latch, the overall mass of the device of the present invention is greatly reduced by 33%, and the actual weight of the device after manufacturing is only 470 grams. The above improvements effectively solve the displacement and weight problems of the wingtip latch in actual use, and improve its engineering applicability.

[0087] (2) The present invention uses a specially modulated nickel-titanium-based shape memory alloy wire, and in the best embodiment, the mass fraction of the nickel element is precisely controlled to be 54.8%. Through strict shape memory processing and training technology, the phase change temperature of the wire is successfully controlled between 100°C and 107°C, ensuring the stable operation of the material within the special service temperature range of the aircraft wingtip. In addition, the 0.3mm diameter driving wire used has been rigorously tested and exhibits excellent mechanical properties. Its maximum tensile strength reaches 1732MPa and its elongation at break is 9.57%. Under a working stress environment of 300MPa, the wire can stably achieve a strain output of 3% for a long time. This material property effectively guarantees the high performance stability of the device during long-term service.

[0088] (3) Conventional wingtip locking devices are usually driven by motors or hydraulic systems. Such systems require an operating voltage of up to 115V, which places high demands on the aircraft power configuration and increases the system complexity and maintenance difficulty. The present invention only requires a DC voltage of 28V to operate normally. This significant voltage reduction not only reduces the complexity and cost of the power supply system, but also facilitates the reasonable arrangement of the device in locations with limited space and power supply capacity, such as wingtips. In addition, since nickel-titanium-based SMA wire has a low phase transition temperature (about 100°C) and excellent deformation recovery ability (maximum strain can reach 7%), it further enhances the technical advantages and application scope of low-voltage drive.

[0089] The present invention successfully achieves structural simplification, significant weight reduction, effective improvement in reliability, and optimization of spatial layout of the aircraft wingtip latch device, providing important technical support for the requirements of lightweight, high reliability, and low maintenance of the aircraft folding wingtip structure.

[0090] Although several embodiments of the present invention have been described herein, those skilled in the art will appreciate that modifications may be made to the embodiments herein without departing from the spirit of the present invention. The above embodiments are merely exemplary and should not be used as limitations on the scope of the present invention.

Claims

1. A shape memory effect driven limit latch device, characterized in that: The position-limiting latch device includes a first SMA wire, a driving module, a locking module, a resetting module, a fixing module and a pin; The first SMA wire contracts when electrically heated, thereby driving the driving module to move; The driving module pushes the pin shaft from the initial position to the full stroke position through mechanical transmission; The locking module is used to lock the position of the pin shaft when the pin shaft extends to the full stroke position; The reset module is used to release the locking state of the locking module and drive the pin shaft to return to the initial position from the full stroke position; The fixing module is used to carry the pin, the first SMA wire, the driving module, the locking module and the resetting module.

2. The shape memory effect driven position limiting latch device according to claim 1, wherein: The first SMA wire is formed into several strands through a pulley group, and the pulley group includes a movable pulley and a fixed pulley; the fixed pulley is arranged at the end of the fixed module, and the movable pulley is arranged on the driving module; both ends of the first SMA wire are fixed to the end of the fixed module; when the first SMA wire is heated and contracted by power, it drives the movable pulley, and then drives the driving module to move toward the end of the fixed module.

3. The shape memory effect driven position limiting latch device according to claim 2, wherein: The pulley block includes one fixed pulley and two movable pulleys, or two fixed pulleys and three movable pulleys, or three fixed pulleys and four movable pulleys.

4. The shape memory effect driven position limiting latch device according to claim 2 or 3, characterized in that: The pin includes a pin end and a flat plate portion adjacent to the pin tail end, and the flat plate portion at the pin tail end is provided with two cross-structure sliding grooves perpendicular to the direction of movement of the pin; The driving module includes a sliding portion and a cross structure; The sliding part is slidably connected to the fixed module and slides along the extension and contraction direction of the pin shaft; the movable pulley is arranged on the sliding part; The cross structure includes two sheet-like parts or rod-like parts, one end of each of the two sheet-like parts or rod-like parts is respectively arranged on the sliding part, and the other end is respectively arranged in the two sliding grooves of the cross structure; When the first SMA wire is energized and heated to shrink, the driving module slides toward the end of the fixing module, driving the two sheet-like parts or rod-like parts of the cross-shaped structure to slide in the sliding groove of the cross-shaped structure, thereby driving the pin shaft to move in the extending direction, and the extending direction of the pin shaft is opposite to the sliding direction of the driving module.

5. The shape memory effect driven position limiting latch device according to claim 1, wherein: The locking module is a limit block, and the pin shaft is provided with a buckle adapted to the shape of the limit block. When the pin shaft reaches the full stroke, the limit block cooperates with the buckle to achieve the limit locking of the pin shaft.

6. The shape memory effect driven position limiting latch device according to claim 5, wherein: The reset module includes a second SMA wire, a rocker arm, a reset spring and a spring positioning column; The second SMA wire is electrically heated and contracted, and the rocker arm is driven to rotate through mechanical transmission, so that the limit block is disengaged from the buckle, and the pin shaft is released from the limit locking state; One end of the spring positioning column is fixed to the end of the fixing module, and the other end is a free end; the reset spring is sleeved on the spring positioning column, one end of the reset spring is against the end of the fixing module, and the other end is against the driving module to provide a reset force for the driving module.

7. The shape memory effect driven position limiting latch device according to claim 5, wherein: The reset module includes a second SMA wire, a rocker arm and a third SMA wire; The second SMA wire is electrically heated and contracted, and the rocker arm is driven to rotate through mechanical transmission, so that the limit block is disengaged from the buckle, and the pin shaft is released from the limit locking state; The third SMA wire contracts when it is energized and heated, and drives the driving module to reset through mechanical transmission.

8. The shape memory effect driven position limiting latch device according to claim 1, wherein: The first SMA wire is a nickel-iron based memory alloy wire with a Ni mass fraction of 50% to 60%, and an austenite phase transition temperature of 80° C. to 130° C. is achieved through training.

9. The shape memory effect driven position limiting latch device according to claim 1, wherein: The first SMA wire is a nickel-iron-based memory alloy wire with a Ni content of 54.8% and an austenite phase transition temperature of 100°C. -107℃。 10. The shape memory effect driven position limiting latch device according to claim 1, wherein: The first SMA wire is replaced with a shape memory polymer SMP wire.

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