Memory metal pin puller

Abstract

The invention relates to a memory metal pin puller, which belongs to the technical field of spacecraft on-orbit unlocking and comprises an insulating bush, a driving shaft, a driving spring, a return spring, a PCB (printed circuit board), a sliding sleeve, a cylindrical roller and a memory metal wire. The driving shaft is in sliding connection with the insulating bush; the driving spring and the return spring are respectively sleeved on the driving shaft; the PCB is arranged close to the first end of the driving shaft; the second end of the driving shaft is far away from the first end; the sliding sleeve is slidably connected with the second end of the driving shaft; the sliding sleeve is provided with a limiting groove, and the cylindrical roller is arranged between the driving shaft and the sliding sleeve; a wire penetrating groove is formed in the outer side of the insulating bush, and the memory metal wire penetrates through the wire penetrating groove and is connected with the PCB. The two-stage unlocking mode is adopted, the pin pulling stroke and bearing capacity are improved, and the pin pulling device is particularly suitable for the large-stroke and large-load working conditions. And during resetting, resetting can be driven by a return spring. In addition, the memory metal wire can be pre-tightened through the return spring, the performance of the device is improved, and the service life of the device is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of on-orbit unlocking of spacecraft, and particularly relates to a shape memory alloy pin puller. Background Art

[0002] In the design and manufacturing process of spacecraft, connection and release mechanisms are crucial components. Some locking mechanisms are responsible for on-orbit unlocking tasks to meet specific functional requirements of the spacecraft. Therefore, these locking mechanisms need to ensure safe and reliable connection or separation of the spacecraft during various stages such as launch, operation, and recovery. Traditional unlocking devices mostly rely on pyrotechnics for unlocking. As an efficient and reliable connection and release device, pyrotechnic unlocking devices also have certain limitations, such as large volume, high unlocking impact, high cost, and strict transportation restrictions. With the development of commercial space technology, non-pyrotechnic pin pullers with low cost, small impact, simplicity, efficiency, and reusability have become ideal supplementary products, and among them, shape memory alloy pin pullers are the key development direction.

[0003] The existing solutions for shape memory alloy pin pullers mainly include two types: primary unlocking and secondary unlocking. In the primary unlocking solution, the pin is directly pulled by the contraction of a shape memory alloy wire (SMA) to achieve unlocking. In the secondary unlocking solution, after the primary pin (such as a pin, roller, ball, etc.) is pulled by the shape memory alloy wire to achieve primary unlocking, the secondary pin is then driven by a spring to achieve secondary unlocking. For example, in the patent "CN109623726A, a shape memory alloy pin puller", a primary pin pulling scheme is adopted, and the pin is directly pulled to unlock by the electrified contraction of the shape memory alloy wire. Further, for application scenarios requiring a large stroke, in the patent "CN217861082U, a pin puller with a large stroke", a secondary pin part is designed, and the secondary pin is separately placed outside the primary pin. After the primary pin is unlocked, the secondary pin is unlocked under the action of a spring. Another example is the patent "CN118143611A, a shape memory alloy pin device", which also adopts a secondary unlocking method. The primary pin is a cylindrical pin vertically inserted into the secondary cylindrical pin. The shape memory alloy wire is bound to the primary pin, and after being electrified, the shape memory alloy wire contracts to unlock the primary pin, and the secondary pin is unlocked under the action of a spring.

[0004] In the existing primary unlocking solutions, the structures of the pin extractors are relatively simple. The pin extractors are fast, have little impact, and are structurally compact. However, due to the small contraction displacement of the shape memory wire, the stroke of the pin extractor is also small, and at the same time, the bearing capacity is small, and self-locking cannot be achieved, making it difficult to be applied in large-load mechanisms. The secondary unlocking solution adopts a two-stage drive. The advantage is that it increases the pin extraction stroke of the pin extractor and can also achieve self-locking; however, the disadvantages are also obvious. Some solutions adopt two sets of unlocking structures, resulting in a large overall volume and inconvenient installation. In addition, with multiple power-on uses, the length of the shape memory wire increases, making the originally tightened shape memory wire become loose and difficult to maintain the tension state. The pin extraction stroke of the shape memory wire in the loose state is insufficient, resulting in incomplete unlocking of the primary pin, and then causing the secondary pin to be stuck. Therefore, the number of uses of such pin extractors is severely restricted by the number of power-on times of the shape memory wire. Especially for working conditions with large strokes and loads, a new structure of the shape memory pin extractor needs to be designed. Summary of the Invention

[0005] To solve the above problems existing in the prior art, the present invention provides a shape memory pin extractor. The technical problems to be solved by the present invention are achieved through the following technical solutions: The present invention provides a shape memory pin extractor, including: an insulating bushing, a drive shaft, a drive spring, a return spring, a PCB board, a sliding sleeve, cylindrical rollers, and a shape memory wire; the drive shaft is slidably connected to the insulating bushing, and the drive spring and the return spring are respectively sleeved on the drive shaft; the PCB board is disposed near the first end of the drive shaft; the second end of the drive shaft is disposed away from its first end; the sliding sleeve is slidably connected to the second end of the drive shaft; the sliding sleeve is provided with a limiting groove, and the cylindrical rollers are disposed between the drive shaft and the sliding sleeve; a wire-passing groove is provided on the outer side of the insulating bushing, and the shape memory wire passes through the wire-passing groove and is connected to the PCB board; wherein, during unlocking, the shape memory wire is electrified to drive the sliding sleeve to move, so that the cylindrical rollers are disengaged from the restraint of the sliding sleeve, and the cylindrical rollers cooperate with the limiting groove; the drive spring drives the drive shaft to move and compresses the return spring; during resetting, the return spring pushes the sliding sleeve to move, so that the cylindrical rollers are disengaged from the cooperation with the limiting groove.

[0006] In an embodiment of the present invention, at least two roller grooves are provided on the drive shaft, and one of the cylindrical rollers is disposed in each roller groove, and all the cylindrical rollers are symmetrically arranged.

[0007] In an embodiment of the present invention, a drive shaft sleeve is disposed inside the insulating bushing. The drive shaft sleeve is coaxially sleeved outside the drive shaft and divides the insulating bushing into a first cavity and a second cavity. Among them, the drive spring is disposed in the first cavity, and the return spring is disposed in the second cavity.

[0008] In an embodiment of the present invention, a vibration isolation pad is disposed on one side of the drive shaft sleeve close to the first cavity, and a limiting step is disposed in the middle of the drive shaft; when unlocking, the limiting step contacts the vibration isolation pad.

[0009] In an embodiment of the present invention, an insulating outer sleeve is disposed outside the insulating bushing, and the shape memory wire is located between the insulating bushing and the insulating outer sleeve.

[0010] In an embodiment of the present invention, a housing is disposed outside the insulating outer sleeve. The housing includes: a flange, a rear sleeve, and a rear cover that are connected in sequence, and the rear cover is located on one side close to the second end of the drive shaft.

[0011] In an embodiment of the present invention, a slider is slidably connected in the second cavity of the insulating bushing, and the sliding sleeve is detachably connected to the slider; among them, several groups of first steel column pins are disposed inside the slider, and the shape memory wire bypasses several groups of the first steel column pins and the surface of the slider and then passes through the wire threading groove.

[0012] In an embodiment of the present invention, an insulating gasket is disposed between the rear cover and the slider.

[0013] In an embodiment of the present invention, several groups of second steel column pins are disposed on one side of the insulating bushing close to the first end of the drive shaft. The shape memory wire bypasses several groups of the first steel column pins and the surface of the slider, and after passing through the wire threading groove, it is wound around several groups of the second steel column pins.

[0014] In an embodiment of the present invention, a pin head is disposed at the first end of the drive shaft, and threaded holes are disposed at both the pin head and the second end of the drive shaft; a through hole is disposed in the middle of the rear cover, and the through hole is coaxially disposed with the threaded hole.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The memory metal pin puller of the present invention adopts a two-stage unlocking method. First, the memory metal wire is energized and contracted to drive the cylindrical roller to achieve the first-stage unlocking. Then, the driving spring drives the driving shaft to move to achieve the second-stage unlocking. The pin pulling stroke and the bearing capacity are improved, and it is particularly suitable for working conditions with large strokes and large loads. When resetting, it can also be driven to reset by a return spring. Through the cooperation of the driving spring and the return spring, the action is smooth, and self-locking and resetting can be achieved, thereby improving the operating efficiency. In addition, the memory metal wire can also be pre-tightened by the return spring, thereby avoiding the problem that the memory metal wire becomes loose after multiple energizations, resulting in insufficient pin pulling stroke, thereby increasing the number of times the pin puller is used, and improving the performance and service life of the device.

[0016] The present invention optimizes the winding method of the memory metal wire, and the PCB board is built-in, with a compact overall structure. The memory metal wire is passed around a slider from the outside, passes through a wire threading groove arranged on an insulating bushing, and is finally connected to the PCB board. The wire winding is convenient, simple and easy to operate, and easy to maintain. The memory metal wire can be directly sleeved on the outside of the insulating sleeve for assembly, which reduces the process difficulty, improves the assembly efficiency, and solves the problems of complex wire winding methods and inconvenient wire winding operations in existing pin pullers.

[0017] The present invention also pre-buries steel column needles in the insulating bushing and the slider respectively. The memory metal wire contacts the steel column needles during the wire winding process, which reduces the problem of contact and friction between the memory metal wire and the edge of the part, increases the service life of the memory metal wire, and reduces the risk of friction breakage of the memory metal wire.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a memory metal pin puller provided by an embodiment of the present invention; Figure 2 It is a structural cross-sectional view of a memory metal pin puller provided by an embodiment of the present invention (locked state); Figure 3 is a structural cross-sectional view of a memory metal pin puller provided by an embodiment of the present invention (unlocked state); Figure 4 is a schematic structural diagram of a drive shaft provided by an embodiment of the present invention; Figure 5 is a schematic diagram of winding the memory metal wire provided by an embodiment of the present invention (first end); Figure 6It is a schematic winding diagram of the shape memory wire (second end) provided by an embodiment of the present invention.

[0020] Icon: 1 - Insulating bushing; 101 - Wire threading groove; 102 - Second steel pin; 2 - Driving shaft; 201 - Pin head; 202 - Roller groove; 203 - Limiting step; 3 - Driving spring; 4 - Return spring; 5 - PCB board; 501 - Solder joint; 6 - Sliding sleeve; 601 - Limiting groove; 7 - Cylindrical roller; 8 - Shape memory wire; 9 - Driving shaft sleeve; 10 - Vibration isolation pad; 11 - Insulating outer sleeve; 12 - Outer housing; 121 - Flange; 122 - Rear sleeve; 123 - Rear cover; 13 - Slide block; 131 - First steel pin; 14 - Insulating gasket; 15 - Limiting screw; 16 - Coil. Detailed implementation manners

[0021] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following provides a detailed description of a shape memory pin puller according to the present invention in combination with the accompanying drawings and specific implementation manners.

[0022] The foregoing and other technical contents, features, and effects of the present invention can be clearly presented in the following detailed description in conjunction with the accompanying drawings. Through the description of the specific implementation manners, a more in-depth and specific understanding of the technical means and effects adopted by the present invention to achieve the intended purpose can be obtained. However, the accompanying drawings are only for reference and illustration, and are not used to limit the technical solution of the present invention.

[0023] Embodiment 1 As Figure 1 , Figure 2 , Figure 3 , Figure 5 and Figure 6 shown, Figure 1 is a schematic structural diagram of a shape memory pin puller provided by an embodiment of the present invention; Figure 2 is a structural sectional view of the shape memory pin puller provided by an embodiment of the present invention (locking state); Figure 3 is a structural sectional view of the shape memory pin puller provided by an embodiment of the present invention (unlocking state); Figure 5 is a schematic winding diagram of the shape memory wire (first end) provided by an embodiment of the present invention; Figure 6 is a schematic winding diagram of the shape memory wire (second end) provided by an embodiment of the present invention.

[0024] This embodiment provides a shape memory alloy pin puller, comprising: an insulating bushing 1, a drive shaft 2, a drive spring 3, a return spring 4, a PCB board 5 (Printed Circuit Board), a sliding sleeve 6, a cylindrical roller 7, and a shape memory alloy wire 8; wherein, the drive shaft 2 is slidably connected to the insulating bushing 1, and the drive spring 3 and the return spring 4 are respectively sleeved on the drive shaft 2; the PCB board 5 is disposed at the first end close to the drive shaft 2; the second end of the drive shaft 2 is disposed away from its first end; the sliding sleeve 6 is slidably connected to the second end of the drive shaft 2; the sliding sleeve 6 is provided with a limiting groove 601, and the cylindrical roller 7 is disposed between the drive shaft 2 and the sliding sleeve 6; a wire passing groove 101 is provided on the outer side of the insulating bushing 1, and the shape memory alloy wire 8 passes through the wire passing groove 101 and is connected to the PCB board 5.

[0025] Exemplarily, a pin head 201 is provided at the first end of the drive shaft 2, and the pin head 201 can extend or retract. Specifically, in the locked state, the pin head 201 extends and remains in the locked state; when unlocking, the pin head 201 retracts. Further, threaded holes are provided at both the end of the pin head 201 of the drive shaft 2 and its second end for connecting a reset tooling through the threaded holes to achieve reset. Taking the reset of one end of the pin head 201 of the drive shaft 2 as an example, during reset, the threaded end of the reset tooling is screwed into the threaded hole at one end of the pin head 201 to pull out the pin head 201, thereby pulling the drive shaft 2. At the same time, the return spring 4 releases elastic energy to push the sliding sleeve 6 to move to achieve reset.

[0026] In the locked state, the drive spring 3 is compressed, and under the combined action of the sliding sleeve 6 and the return spring 4, the cylindrical roller 7 maintains balance between the drive shaft 2 and the sliding sleeve 6, that is, the cylindrical roller 7 is constrained between the drive shaft 2 and the sliding sleeve 6, so that the cylindrical roller 7 is constrained in both the radial direction and the axial direction without being subjected to external forces. Herein, the axial direction is defined as the direction from the first end of the drive shaft 2 pointing to its second end, and the radial direction is defined as the diameter direction of the drive shaft 2. The pin head 201 of the drive shaft 2 extends and remains in the locked state.

[0027] When unlocking, the shape memory alloy wire 8 is energized. Since the shape memory alloy wire 8 contracts after being heated to drive the sliding sleeve 6 to move, the cylindrical roller 7 is disengaged from the constraint of the sliding sleeve 6. Under the push of the drive shaft 2, the cylindrical roller 7 rolls into the limiting groove 601 of the sliding sleeve 6 and cooperates with the limiting groove 601. That is, at this time, the cylindrical roller 7 is disengaged from the constraint in the radial direction. At the same time, the constraint in the axial direction of the drive shaft 2 is also released, and the elastic energy of the drive spring 3 is released. The drive spring 3 drives the drive shaft 2 to move, compressing the return spring 4, and completing the unlocking of the pin head 201.

[0028] During reset, the pin head 201 can be pulled out by a reset tooling, the elastic energy of the return spring 4 is released, and the sliding sleeve 6 is pushed by the return spring 4. At this time, the cylindrical roller 7 disengages from the cooperation with the limit groove 601, and the cylindrical roller 7 also falls back into the roller groove 202 of the drive shaft 2, and the shape memory wire 8 is pre-tightened again. The shape memory pin puller of this embodiment returns to the locked state again.

[0029] It can be understood that the structure of the reset tooling is not limited in this embodiment. For example, it can also be connected to the threaded hole of the drive shaft 2 through bolts or screws, so as to realize the effect of pulling or pushing the drive shaft 2 to achieve reset.

[0030] It should be noted that the shape memory pin puller of this embodiment restricts the first-stage unlocking through the cylindrical roller 7, drives the first-stage unlocking through the shape memory wire 8, and then realizes the second-stage unlocking through the driving spring 3, which increases the pin pulling stroke and driving force, and can also realize the self-locking of the pin head 201 after pin pulling. It also has the advantages of fast pin pulling speed, high reliability, and many repeated times, and is suitable for working conditions with large stroke and large load. In addition, the shape memory wire 8 is pre-tightened by the return spring 4, so that the shape memory wire 8 can be kept in a tensioned state in real time. The number of usage times is not limited by multiple power-on, and the shape memory wire 8 does not need to be trained multiple times before use, which reduces the usage requirements and solves the problem that the pin pulling stroke is insufficient due to the slack state, and further the problem that the secondary pin is stuck due to the incomplete unlocking of the primary pin. Specifically, after pre-tightening and secondary unlocking, the pin pulling stroke of the shape memory pin puller of this embodiment can reach 5 mm, and the bearing capacity range can reach 400 N to 600 N. In addition, the bearing capacity of the pin puller can be improved by replacing the driving spring 3 with a larger bearing capacity, which can meet the requirements of stroke and load.

[0031] In addition, the shape memory pin puller of this embodiment combines the low energy consumption characteristics of the shape memory wire 8 and the precise control through the PCB board 5, and has the advantages of strong adaptability and simple maintenance, and has significant practical value and economic benefits.

[0032] As Figure 4 shown, Figure 4 is a schematic structural diagram of the drive shaft provided by the embodiment of the present invention.

[0033] In an optional embodiment, at least two roller grooves 202 are provided on the drive shaft 2, and a cylindrical roller 7 is provided in each roller groove 202, and all the cylindrical rollers 7 are symmetrically arranged.

[0034] Exemplarily, taking the case where two roller grooves 202 are provided as an example, the two roller grooves 202 are symmetrically arranged, and the two cylindrical rollers 7 are also symmetrically arranged in the two roller grooves 202, so that the bearing capacity received on the drive shaft 2 is evenly distributed.

[0035] Exemplarily, the cylindrical roller 7 of this embodiment can be replaced with round balls.

[0036] Please refer again to Figure 2 and Figure 3 , in an alternative embodiment, a drive shaft sleeve 9 is provided inside the insulating bushing 1. The drive shaft sleeve 9 is coaxially sleeved outside the drive shaft 2 and divides the insulating bushing 1 into a first cavity and a second cavity.

[0037] Exemplarily, the cavity near the first end of the drive shaft 2 is the first cavity, and the drive spring 3 is arranged in the first cavity; the cavity near the second end of the drive shaft 2 is the second cavity, and the return spring 4 is arranged in the second cavity.

[0038] Exemplarily, the drive shaft sleeve 9 and the drive shaft 2 can adopt an interference fit to achieve sealing and prevent foreign objects from entering the cavity.

[0039] As Figures 2 to 4 shown, where Figure 4 is a schematic structural view of the drive shaft provided by an embodiment of the present invention.

[0040] Furthermore, a limiting step 203 is provided in the middle of the drive shaft 2, and a vibration isolation pad 10 is provided on the side of the drive shaft sleeve 9 close to the first cavity; when unlocking, the limiting step 203 contacts the vibration isolation pad 10.

[0041] Exemplarily, when unlocking, the drive shaft 2 is driven to move by the drive spring 3, and the limiting step 203 impacts on the vibration isolation pad 10 to reduce the impact force during unlocking.

[0042] Furthermore, the vibration isolation pad 10 can adopt rubber or silicone buffer materials.

[0043] In an alternative embodiment, an insulating outer sleeve 11 is provided outside the insulating bushing 1, and the shape memory wire 8 is located between the insulating bushing 1 and the insulating outer sleeve 11.

[0044] Exemplarily, the insulating bushing 1, the insulating outer sleeve 11 and the slider 13 can all adopt non-metallic materials. For example, polyimide can be used. As an engineering plastic, polyimide has the characteristics of high temperature resistance and high strength. Or the insulating bushing 1 and the slider 13 can also adopt metal parts. To ensure insulation, an insulating coating treatment can be performed on the outer surfaces of the insulating bushing 1 and the slider 13.

[0045] It should be noted that both the insulating bushing 1 and the insulating outer sleeve 11 are made of insulating materials. Additionally, insulation can also be achieved through an insulating plating process or an insulating coating process. Among them, the insulating plating process can form an insulating coating on the material surface through chemical treatment, and the insulating coating process can use polyurethane insulating paint or ceramic insulating paint to achieve the insulating effect. Since the shape memory alloy wire 8 needs to be in direct contact with the insulating bushing 1 and the insulating outer sleeve 11, good external insulation can be achieved by using insulating materials or insulating processes, improving the working safety and stability of the shape memory alloy wire 8. In other words, the use of the insulating bushing 1 and the insulating outer sleeve 11 effectively isolates the electrical and mechanical components, enhancing safety.

[0046] In an alternative embodiment, an outer housing 12 is provided outside the insulating outer sleeve 11. The outer housing 12 includes a flange 121, a rear sleeve 122, and a rear cover 123 that are connected in sequence. The rear cover 123 is located on one side close to the second end of the drive shaft 2.

[0047] In an alternative embodiment, a slider 13 is slidably connected in the second cavity of the insulating bushing 1, and the sliding sleeve 6 is detachably connected to the slider 13.

[0048] Exemplarily, the sliding sleeve 6 and the slider 13 can be connected into one body by fastening screws.

[0049] Exemplarily, an insulating gasket 14 is provided between the rear cover 123 and the slider 13, further achieving insulation at the contact position with the shape memory alloy wire 8.

[0050] Exemplarily, a through hole is provided in the middle of the rear cover 123. The through hole is coaxially arranged with the threaded hole of the drive shaft 2. During reset, the threaded end of the reset tooling is passed through the through hole in the middle of the rear cover 123 and threadedly connected to the threaded hole of the drive shaft 2, thereby pushing the drive shaft 2 to move for reset. With this end reset, there is no need to remove the pin head 201, and the reset is convenient and the operation is simple.

[0051] Please refer to Figures 2 to 4 , in an alternative embodiment, the shape memory alloy pin extractor of this embodiment is further provided with a limit screw 15. After passing through the rear sleeve 122 and the insulating outer sleeve 11, the limit screw 15 is connected to the insulating bushing 1 to limit the insulating bushing 1 in the axial direction.

[0052] In an alternative embodiment, the shape memory alloy pin extractor of this embodiment is further provided with a coil 16. The coil 16 is arranged on the rear sleeve 122 and is located on the opposite side of the limit screw 15. The PCB board 5 is connected to an external circuit line through the coil 16 for controlling the energization of the shape memory alloy wire 8.

[0053] Existing memory metal pin extractors generally still have the problems of complex wire winding methods and inconvenient wire winding operations. In addition, there is a certain friction between the memory metal wire and the contact position, and after working a certain number of times, there is also a risk of friction fracture of the memory metal wire.

[0054] In view of this, in this embodiment, the wire winding method of the memory metal wire 8 is optimized, which not only reduces the process difficulty but also improves the service life of the memory metal wire 8.

[0055] Please refer to Figure 5 and Figure 6 , in this embodiment, several groups of first steel column pins 131 are arranged in the slider 13. After the memory metal wire 8 bypasses several groups of first steel column pins 131 and the surface of the slider 13, it passes through the wire threading groove 101; on one side of the first end of the insulating bushing 1 close to the driving shaft 2, several groups of second steel column pins 102 are arranged. The memory metal wire 8 bypasses several groups of first steel column pins 131 and the surface of the slider 13, and after passing through the wire threading groove 101, it is wound around several groups of second steel column pins 102.

[0056] Exemplarily, wire threading grooves 101 are symmetrically arranged on both sides of the insulating bushing 1. Among them, two wire threading grooves 101 are arranged at intervals on each side, and at least one memory metal wire 8 can pass through each wire threading groove 101.

[0057] Exemplarily, the memory metal wire 8 adopts a ferrule method in the wire winding method. Two second steel column pins 102 are arranged at intervals in the axial direction, and four first steel column pins 131 are evenly arranged at the turning positions of the memory metal wire 8, so that the memory metal wire 8 does not directly contact the edge of the part, reducing the risk of fracture of the memory metal wire 8 due to friction.

[0058] Exemplarily, the four first steel column pins 131 are arranged parallel to each other, the axis direction thereof is perpendicular to the extending direction of the wire threading groove 101, and at the same time the axis direction is also parallel to the surface of the slider 13.

[0059] Further, the memory metal wire 8 is wound around two second steel column pins 102 and passes through the wire threading groove 101. The memory metal wire 8 extends along the wire threading groove 101, winds around the first steel column pin 131 at the turning position, then continues to wind around another group of first steel column pins 131 after bypassing the surface of the slider 13. After bypassing the first steel column pin 131, the memory metal wire 8 continues to extend along the wire threading groove 101 on the other side of the insulating bushing 1, and finally the two ends of the memory metal wire 8 are respectively welded to two solder joints 501 of the PCB board 5.

[0060] It is worth noting that the memory metal pin puller of the present embodiment optimizes the winding method of the memory metal wire 8, and the PCB board 5 is built-in. The overall structure is compact. The memory metal wire 8 passes around the slider 13 from the outside, passes through the wire threading groove 101 set on the insulating bushing 1, and is finally connected to the PCB board 5. The wire winding is convenient, simple and easy to operate, and easy to maintain. The memory metal wire 8 can be directly put on the outside of the insulating bushing 1 for assembly, which reduces the process difficulty, improves the assembly efficiency, and solves the problems of complex wire winding method and inconvenient wire winding operation in the existing pin puller.

[0061] In addition, the memory metal pin puller of the present embodiment also pre-buries steel column needles in the insulating bushing 1 and the slider 13, namely, the second steel column needle 102 and the first steel column needle 131. The memory metal wire 8 contacts the steel column needles during the wire winding process, which reduces the contact friction between the memory metal wire 8 and the edge of the part, avoids the problem of high-temperature melting of the memory metal wire 8 when power is turned on after the memory metal wire 8 contacts the non-metallic parts, improves the service life of the memory metal wire 8, and reduces the risk of friction breakage of the memory metal wire 8.

[0062] Generally speaking, the memory metal pin puller of the present embodiment improves the winding method of the memory metal wire 8, improves the assembly efficiency of the pin puller and reduces the defect rate. Compared with the existing wire winding method, the PCB board 5 and the memory metal wire 8 are directly sleeved on the outside of the insulating bushing 1 after welding, which gets rid of the coupling problem between the memory metal wire 8 and the insulating bushing 1 during wire winding, simplifies the assembly process, and achieves the effect of mutual coordination and assembly of the insulating bushing 1, the PCB board 5 and the memory metal wire 8. At the same time, the PCB board 5 is placed inside the pin puller, and is connected to electricity after being led out through a wire, so that the product appearance is more concise, and improper operation can be avoided to cause a short circuit or damage to the PCB board 5.

[0063] For easier understanding, please refer to Figure 2 and Figure 3 As shown in the figure, the left direction and the right direction are represented, wherein the left direction to the right direction is from the first end of the drive shaft 2 to the second end thereof, that is, along the axial direction. When the pin puller is unlocked, the drive shaft 2 moves to the right end, the PCB board 5 is placed on the left side, and the movement of the sliding sleeve 6 is not affected.

[0064] The working principle of the memory metal pin puller of this embodiment is that the memory metal wire 8 passes through the slider 13 and the insulating bushing 1 and is connected to the PCB board 5. After the memory metal wire 8 is energized, it shrinks, pulling the slider 13 and the sleeve 6 to move to the left together, the radial constraint of the cylindrical roller 7 is released, and the driving spring 3 in the compressed state pushes the driving shaft 2 to move to the right. Under the pressure of the driving shaft 2, the cylindrical roller 7 rolls into the groove of the sleeve 6, the driving shaft 2 moves to the right smoothly, the energy of the driving spring 3 is released, and the return spring 4 is compressed. After the driving shaft 2 moves to the right to the bottom, it hits the vibration isolation pad 10, reducing the impact force when unlocking.

[0065] After unlocking, the drive shaft 2 is locked. The drive spring 3 continuously pushes the drive shaft 2 to the right, and the pin head 201 achieves self-locking. When resetting, just screw the screw into the threaded hole, pull the drive shaft 2 to the left, and the return spring 4 pushes the sliding sleeve 6 to the right to move, and the cylindrical roller 7 falls back into the roller groove 202 of the drive shaft 2 to achieve reset. It can also be connected through the central through hole of the rear cover 123 and the threaded hole at the rear end of the drive shaft 2, and push the drive shaft 2 to move to the left to achieve reset.

[0066] The memory metal pin extractor of the present invention adopts a two-stage unlocking method. First, the memory metal wire is energized and shrunk to drive the cylindrical roller to achieve the first-stage unlocking, and then the drive spring drives the drive shaft to move to achieve the second-stage unlocking. Both the pin extraction stroke and the bearing capacity are improved, especially suitable for working conditions with large stroke and large load. When resetting, it can also be driven to reset by the return spring. Through the cooperation of the drive spring and the return spring, the action is ensured to be stable, self-locking and reset can be achieved, and the operation efficiency is improved. In addition, the return spring can also pre-tighten the memory metal wire, avoiding the problem that the memory metal wire becomes loose after multiple energizations, resulting in insufficient pin extraction stroke, increasing the number of uses of the pin extractor, and improving the performance and service life of the device.

[0067] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant are intended to cover non-exclusive inclusion, so that an article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the article or device including the said element. Terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The orientation or positional relationship indicated by "up", "down", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention.

[0068] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, several simple deductions or substitutions can be made, and all should be regarded as belonging to the protection scope of the present invention.

Claims

1. A shape memory alloy pin puller, characterized in that, Comprising: An insulating bushing (1), a drive shaft (2), a drive spring (3), a return spring (4), a PCB board (5), a sliding sleeve (6), cylindrical rollers (7) and a shape memory wire (8); The drive shaft (2) is slidably connected to the insulating bushing (1), and the drive spring (3) and the return spring (4) are respectively sleeved on the drive shaft (2); the PCB board (5) is arranged near the first end of the drive shaft (2); The second end of the drive shaft (2) is arranged away from its first end; the sliding sleeve (6) is slidably connected to the second end of the drive shaft (2); a limiting groove (601) is arranged on the sliding sleeve (6), and the cylindrical rollers (7) are arranged between the drive shaft (2) and the sliding sleeve (6); A wire threading groove (101) is arranged on the outer side of the insulating bushing (1), and the shape memory wire (8) passes through the wire threading groove (101) and is connected to the PCB board (5); Wherein, when unlocking, the shape memory wire (8) is electrified to drive the sliding sleeve (6) to move, so that the cylindrical rollers (7) are disengaged from the constraint of the sliding sleeve (6), the cylindrical rollers (7) cooperate with the limiting groove (601), the drive spring (3) drives the drive shaft (2) to move, and compresses the return spring (4); when resetting, the return spring (4) pushes the sliding sleeve (6) to move, so that the cylindrical rollers (7) are disengaged from the cooperation with the limiting groove (601).

2. The shape memory alloy pin puller according to claim 1, characterized in that, At least two roller grooves (202) are arranged on the drive shaft (2), and one of the cylindrical rollers (7) is arranged in each roller groove (202), and all the cylindrical rollers (7) are symmetrically arranged.

3. The shape memory alloy pin puller according to claim 1, characterized in that, A drive shaft sleeve (9) is arranged in the insulating bushing (1), the drive shaft sleeve (9) is coaxially sleeved outside the drive shaft (2), and divides the insulating bushing (1) into a first cavity and a second cavity, wherein, the drive spring (3) is arranged in the first cavity, and the return spring (4) is arranged in the second cavity.

4. The shape memory alloy pin puller according to claim 3, wherein, A vibration isolation pad (10) is arranged on one side of the drive shaft sleeve (9) close to the first cavity, and a limiting step (203) is arranged in the middle of the drive shaft (2); When unlocking, the limiting step (203) contacts the vibration isolation pad (10).

5. The shape memory alloy pin puller according to claim 1, characterized in that An insulating outer sleeve (11) is arranged outside the insulating bushing (1), and the shape memory wire (8) is located between the insulating bushing (1) and the insulating outer sleeve (11).

6. The shape memory alloy pin puller according to claim 5, wherein An outer housing (12) is arranged outside the insulating outer sleeve (11), and the outer housing (12) comprises: a flange (121), a rear sleeve (122) and a rear cover (123) which are connected in sequence, and the rear cover (123) is located on one side close to the second end of the drive shaft (2).

7. The shape memory alloy pin puller according to claim 6, wherein A slider (13) is slidably connected in the second cavity of the insulating bushing (1), and the sliding sleeve (6) is detachably connected to the slider (13); Among them, several groups of first steel column pins (131) are arranged inside the slider (13), and the shape memory wire (8) bypasses several groups of the first steel column pins (131) and the surface of the slider (13) and then passes through the wire threading groove (101).

8. The shape memory alloy pin puller according to claim 7, wherein An insulating gasket (14) is arranged between the rear cover (123) and the slider (13).

9. The shape memory alloy pin puller according to claim 8, characterized in that, On one side of the first end of the insulating bushing (1) close to the drive shaft (2), several groups of second steel column pins (102) are arranged. The shape memory wire (8) bypasses several groups of the first steel column pins (131) and the surface of the slider (13), passes through the wire threading groove (101), and then winds around several groups of the second steel column pins (102).

10. The shape memory alloy pin puller according to claim 6, wherein A pin head (201) is arranged at the first end of the drive shaft (2), and threaded holes are arranged at both the pin head (201) and the second end of the drive shaft (2); a through hole is arranged in the middle of the rear cover (123), and the through hole is coaxially arranged with the threaded hole.

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