Magnetic conversion flexible temporary fastener

Abstract

The application relates to a magnetic conversion type flexible temporary fastener which comprises a shell, a switch assembly, a magnetic control assembly and a clamping assembly; the magnetic conversion type flexible temporary fastener introduces a magnetic control assembly, the relative movement of a magnet and a shielding frame changes the spatial magnetic field generated by the magnet, so that the magnetic control assembly generates magnetic attraction to an abutting table, and then a top rod can be firmly inserted into a pawl to maintain the fastening effect on an aircraft panel wall, which is favorable for simplifying the assembly process and improving the stability and safety of aircraft assembly; the magnetic focusing effect of a magnetic conductive cover can further change the distribution of the spatial magnetic field, so as to accurately control the magnetic attraction of the magnetic control assembly to the abutting table; the temporary fastener has a clever structure design, stable clamping state and simple assembly.

Description

Technical Field

[0001] This invention relates to the technical field of aerospace assembly, and in particular to a magnetic conversion type flexible temporary fastener. Background Technology

[0002] With the rapid development of the aerospace industry, the aerospace fastener industry has ushered in an unprecedented new era. Aerospace fasteners are widely used in the production and maintenance of commercial and military aircraft, ballistic missiles, and rockets. During aircraft assembly, whether it's component assembly or modular assembly, temporary fastening devices are needed to temporarily connect two thin-walled parts or components. Before the final assembly of thin-plate components, temporary fasteners are usually inserted into pre-drilled holes for temporary assembly, and then removed after assembly. Aircraft panels are mainly assembled from skin and stringers. The general process of assembling aircraft panels, from component to part, is as follows: part or component positioning → initial hole drilling → temporary fastener pre-connection → drilling numerous final holes → selecting some final hole connections → removing temporary fasteners → enlarging initial holes to final holes → disassembly and gluing → resetting and final connection. Because aircraft panels vary in thickness, the length of fastener connections and installation time are inconsistent. Therefore, a large number of temporary fasteners are required during aircraft assembly, and they must be highly accurate in positioning, simple in assembly, quick in assembly and disassembly, and adaptable to pre-connection of aircraft panels of different thicknesses.

[0003] Traditional fastening methods mostly employ through-hole clamps or ordinary bolts for temporary fixation. Current technology, using manual tightening of ordinary bolts for these temporary connections, suffers from drawbacks such as complex operation, excessive or insufficient clamping force, high overall cost, and difficulty in integrating with automated assembly systems. Furthermore, both of these connection methods require simultaneous operation on both sides of the panel, complicating the assembly process, making precise positioning difficult, and the clamping force, relying on manual judgment, cannot be precisely controlled, resulting in inconsistent and fluctuating clamping force. The inability to automate assembly significantly impacts product assembly quality and efficiency. Therefore, it is necessary to introduce new structures during the installation and removal of temporary fasteners to improve assembly quality and efficiency.

[0004] Please see Figure 1This is a cross-sectional view along the central axis of a temporary fastener in the related art. The temporary fastener includes a housing 2, a clamping assembly, and a switch 32. The clamping assembly includes an expansion sleeve 6, a push rod 5, a first compression spring 8, and a second compression spring 7. The expansion sleeve 6 includes a claw 62 and an abutment platform 61. The end of the claw 62 protrudes from the housing 2, and the abutment platform 61 is located in the inner cavity of the housing 2 and fixed to the top of the claw 62. The claw 62 includes a sleeve 621 and a locking platform 622 disposed at the end of the sleeve 621. The end of the sleeve 621 can be opened and closed by external force, and the outer diameter of the locking platform 622 can be changed. The abutment platform 61 includes a first abutment portion 611 and a second abutment portion 622 with different heights, and the first abutment portion 611 is located inside the second abutment portion 612; a first compression spring 8 is disposed between the second abutment portion 612 and the bottom surface of the housing 2, and a second compression spring 7 is disposed between the first abutment portion 612 and the switch 32. The top end of the push rod 5 is fixed to the switch 32, and its end passes through the second compression spring 7 and the abutment platform 61 in sequence and is inserted into the sleeve 621. It moves along the axial direction of the sleeve 621, causing the end of the sleeve 621 to open and close, thereby changing the outer diameter of the locking platform 622.

[0005] The temporary fastener is placed on the upper panel 11 of the aircraft, and the claw 62 exposed on the housing 2 is inserted into the pre-drilled hole 13. Pressing switch 32 pushes the push rod 5 towards the bottom surface of the housing 2, causing the second clamping spring 7, expansion sleeve 6, and first clamping spring 8 to also move towards the bottom surface of the housing 2. Simultaneously, the push rod 5 inserts into the sleeve 621, increasing the inner diameter of the end of the sleeve 621 until the outer diameter of the locking platform 622 is greater than the inner diameter of the pre-drilled hole 13. Partially releasing switch 32 causes the expansion sleeve 6 and push rod 5 to partially rebound towards switch 32 under the elastic force of the second clamping spring 7 and the first clamping spring 8, until the locking platform 622 hooks onto the lower panel 12, preventing the first clamping spring 8 from further pushing the expansion sleeve 6. During this process, switch 32 needs to be continuously pressed to compress the first and second clamping springs, and the rebound force generated by the two clamping springs maintains the clamping force of the temporary fastener on the aircraft panel. If switch 32 is fully released, the first clamping spring 8 and the second clamping spring 7 will return to their original positions, and the push rod 5 will completely disengage from the sleeve 621. The end of the sleeve 621 will close, and the outer diameter of the locking platform 622 will decrease, preventing it from hooking onto the lower panel 12 of the aircraft. At this time, the temporary fastener cannot perform its intended temporary fastening function, and its clamping state is not stable enough, increasing the difficulty and complexity of fastener installation and removal, making it unsuitable for aircraft assembly with high safety and stability requirements. Summary of the Invention

[0006] Based on this, the purpose of the present invention is to provide a magnetic conversion flexible temporary fastener with a more stable clamping state.

[0007] This invention is achieved through the following technical solution:

[0008] A magnetic conversion type flexible temporary fastener includes a housing, a switching assembly, a magnetic control assembly, and a clamping assembly;

[0009] The switch assembly is disposed on the housing, and the switch assembly and the housing together form a receiving cavity;

[0010] The magnetic control assembly is disposed within the housing, located between the switch assembly and the clamping assembly. The magnetic control assembly includes a magnet, an antiferromagnetic shielding frame, and two magnetically conductive covers. The shielding frame is U-shaped, comprising two strip-shaped sidewalls and a strip-shaped bottom wall. The two strip-shaped sidewalls are parallel to each other, and the two ends of the strip-shaped bottom wall are respectively connected to the bottom ends of the two strip-shaped sidewalls. The two magnetically conductive covers are respectively disposed on both sides of the shielding frame, and together with the shielding frame, form a protective outer shell enclosing the bottom and sides of the magnet. The protective outer shell is engaged with the inner wall of the housing and can slide axially within the housing. The magnet is disposed within the protective outer shell and can rotate axially, with its two magnetic poles pointing radially.

[0011] The clamping assembly includes an expansion sleeve, a push rod, a first clamping spring, and a second clamping spring; the expansion sleeve includes a claw and a magnetically conductive abutment; wherein, the claw includes a sleeve and a clamping platform disposed at the end of the sleeve, the abutment platform being fixed to the top end of the sleeve; one end of the push rod is fixedly connected to the magnetic control assembly, and the other end of the push rod passes through the abutment platform and is inserted into the sleeve, and its axial movement along the sleeve causes the outer diameter of the clamping platform to change; the first clamping spring is located between the clamping platform and the abutment platform and is sleeved on the outer periphery of the sleeve; the second clamping spring is located between the abutment platform and the strip-shaped bottom wall and is sleeved on the outer periphery of the push rod;

[0012] The switch assembly includes a switch; the surface of the switch facing the magnet has a locking part, which locks into the top surface of the magnet; the switch is used to drive the magnet to perform axial displacement or rotation.

[0013] The magnetic conversion flexible temporary fastener of this invention introduces a magnetic control component, which changes the spatial magnetic field generated by the magnet by driving the relative movement of the magnet and the shielding frame. The magnetic binding effect of the two magnetic shields can further change the distribution of the spatial magnetic field. When the magnet is rotated by the switch so that the two magnetic poles of the magnet are respectively facing the two strip-shaped sidewalls of the shielding frame, the spatial magnetic field generated by the magnet is located only on the side of the magnet due to the magnetic binding effect of the two magnetic shields, and there is no spatial magnetic field below the magnet. Therefore, the magnetic control component does not have a magnetic attraction to the abutment platform. When the two magnetic poles of the magnet are both far away from the two strip-shaped sidewalls of the shielding frame, the spatial magnetic field generated by the magnet is interrupted by the antiferromagnetic shielding frame, which interrupts the "magnetic field lines" generated by the two magnetic poles of the magnet on the side of the magnet. The spatial magnetic field generated below the magnet allows the magnetic control component and the abutment platform to be firmly connected by magnetic attraction. Because the magnetic control assembly has a magnetic attraction effect on the contact platform, the push rod can remain inserted in the sleeve of the claw even without continuous external force, causing the contact platform to hook onto the lower panel of the aircraft. This clamps the upper and lower panels of the aircraft between the contact platform and the first clamping spring, improving the stability of the clamping state and reducing the complexity of loading and unloading, thus simplifying the aircraft assembly process. Furthermore, the rebound force generated when the first clamping spring is compressed provides a certain clamping force to the temporary fastener, and any matched first clamping spring, when providing appropriate clamping force, can adapt to changes in the thickness of the aircraft panel, exhibiting a certain degree of universality.

[0014] Furthermore, the two magnetic shields are each provided with a magnetic platform on their bottom surfaces facing the contact platform. The magnetic platform can further confine the magnetic field lines, enhance the spatial magnetic field below the magnet, and thus increase the magnetic attraction force of the magnetic control component on the contact platform.

[0015] Furthermore, the stiffness coefficient of the second compression spring is greater than that of the first compression spring. In the tightened state, the second compression spring further compresses the first compression spring, thereby increasing the clamping force of the temporary fastener; during disassembly, the second compression spring overcomes part of the rebound force of the first compression spring, causing the push rod to disengage from the sleeve and separating the push rod from the sleeve. By selecting appropriate stiffness for the first and second compression springs, it is possible to adapt to aircraft panels of different thicknesses, thereby improving the quality and efficiency of aircraft assembly.

[0016] Furthermore, the abutment platform includes a first abutment portion and a second abutment portion of different heights, with the first abutment portion located inside the second abutment portion; the first compression spring is located between the second abutment portion and the snap-fit ​​platform and is sleeved on the outer periphery of the first abutment portion and the sleeve; the push rod passes through the first abutment portion; the second compression spring is located between the first abutment portion and the shielding frame. The first abutment portion and the second abutment portion can limit the first compression spring and the second compression spring, so that the temporary fastener is subjected to uniform force internally.

[0017] Furthermore, the switch assembly also includes a switch cover, which is a hollow cover-shaped structure with two symmetrically distributed limiting walls on its inner sidewall. The limiting walls include a first limiting wall and a second limiting wall that are staggered and connected to each other. The switch is disposed on the inner side of the switch cover, and its outer periphery is provided with symmetrically distributed limiting protrusions.

[0018] Furthermore, the switch assembly also includes a magnetically conductive skin fixed to the top surface of the switch. This skin is controlled by an external magnetic field to drive the axial movement and rotation of the switch.

[0019] Furthermore, the sleeve is a tubular structure formed by multiple spring pieces; the snap-fit ​​platform is disposed on the outer wall of each spring piece and extends outward to form a hook-shaped structure.

[0020] Furthermore, the magnet has a rotationally symmetric structure in which the axis of rotation coincides with the axis of the push rod; the two magnetic poles of the magnet are perpendicular to the axis of the push rod and can rotate around the axis of the push rod.

[0021] Furthermore, the shielding frame is fixedly connected to the two magnetic shields to form a cylindrical outer shell that encloses the magnet; the thickness of the sidewalls of the two magnetic shields is greater than the thickness of the two strip sidewalls of the shielding frame, and a groove is formed at the strip sidewall of the shielding frame, and the inner wall of the shell is provided with a boss corresponding to the groove.

[0022] Furthermore, the housing is a hollow cylindrical structure, including an open end and a closed end; the switch assembly is disposed at the open end of the housing, forming an accommodating cavity with the housing; a central hole is provided at the center of the closed end, the end of the sleeve passes through the central hole, and the snap-fit ​​platform is exposed outside the housing.

[0023] Compared with existing technologies, the present invention provides a magnetic conversion flexible temporary fastener that introduces a magnetic control component. The relative movement of the magnet and the shielding frame alters the spatial magnetic field generated by the magnet, thereby causing the magnetic control component to magnetically attract the contact platform. This allows the push rod to be firmly inserted into the claw to maintain the fastening effect on the aircraft panel, simplifying the assembly process and improving the stability and safety of aircraft assembly. The magnetic concentrating effect of the magnetic guide shield further alters the distribution of the spatial magnetic field, thereby precisely controlling the magnetic attraction force of the magnetic control component on the contact platform. Furthermore, the magnetic guide platform can converge magnetic field lines, enhancing the spatial magnetic field below the magnet, thus increasing the magnetic attraction force of the magnetic control component on the contact platform. In addition, the use of compression springs with different stiffness coefficients facilitates adaptation to aircraft panels of varying thicknesses, further simplifying the assembly process. This temporary fastener has a simple overall structure, ingenious design, and stable clamping state, significantly improving the quality and efficiency of aircraft assembly.

[0024] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view along the central axis of a temporary fastener in the related art;

[0026] Figure 2 A front view of a magnetic conversion type flexible temporary fastener provided by the present invention;

[0027] Figure 3 A cross-sectional view along section AA of a magnetic conversion flexible temporary fastener provided by the present invention;

[0028] Figure 4 A three-dimensional structural diagram of the expansion sleeve provided by the present invention;

[0029] Figure 5 A front view of the expansion sleeve provided by the present invention;

[0030] Figure 6 A three-dimensional structural diagram of the permanent magnet provided by the present invention;

[0031] Figure 7 A three-dimensional structural diagram of the shielding frame provided by the present invention;

[0032] Figure 8 A three-dimensional structural diagram of the magnetic shield provided by the present invention;

[0033] Figure 9 A front view of the magnetic shield provided by the present invention;

[0034] Figure 10 A three-dimensional structural diagram of the switch assembly provided by the present invention;

[0035] Figure 11A magnetic field line distribution diagram of the magnetic control component provided by the present invention in a first state;

[0036] Figure 12 The magnetic field line distribution diagram of the magnetic control component provided by the present invention in the second state.

[0037] Figure labels: Upper wall plate 11, Lower wall plate 12, Pre-drilled hole 13, Housing 2, Switch cover 31, Limiting wall 311, First limiting wall 311a, Second limiting wall 311b, Switch 32, Limiting boss 321, Engraving part 322, Skin 33, Magnet 41, Shielding frame 42, Strip bottom wall 421, Strip side wall 422, Magnetic guide cover 43, Magnetic guide platform 431, Top rod 5, Expansion sleeve 6, Abutment platform 61, First abutment part 611, Second abutment part 612, Claw 62, Sleeve 621, Engraving platform 622, Second compression spring 7, First compression spring 8. Detailed Implementation

[0038] Existing temporary fasteners used for unidirectional loading and unloading rely solely on compression springs to provide clamping force on aircraft panels, posing significant safety hazards during aircraft assembly. This is because such temporary fasteners have poor clamping force and unstable clamping states, failing to achieve high safety and stability. Therefore, this invention introduces a magnetic control component into the temporary fastener. By changing the direction of the magnetic field lines emitted by the magnetic control component, magnetic attraction can be generated or not generated between the component and the contact platform. This enhances the clamping force of the clamping component on the aircraft panel, improves the stability of the clamping state, and facilitates automated unidirectional loading and unloading of the temporary fastener. Furthermore, changing the spring constant helps the temporary fastener adapt to aircraft panels of varying thicknesses, thereby reducing loading and unloading complexity.

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the present invention will be further described in detail below through a specific embodiment.

[0040] Please also refer to Figures 2-3 ,in, Figure 2 This is a front view of a magnetic conversion type flexible temporary fastener provided by the present invention. Figure 3 for Figure 2 The diagram shows a cross-sectional view of a magnetic conversion flexible temporary fastener along section AA. This magnetic conversion flexible temporary fastener includes a housing 2, a clamping assembly, a magnetic control assembly, and a switching assembly. The housing 2 and the switching assembly enclose a cavity that houses the clamping assembly and the magnetic control assembly. The clamping assembly provides clamping force to clamp the upper panel 11 and the lower panel 12 of the aircraft together. The switching assembly controls the clamping force of the clamping assembly through the magnetic control assembly.

[0041] The housing 2 is a hollow cylindrical structure, including an open end and a closed end; the switch assembly is located at the open end of the housing, and the magnet, the shield, the two magnetic shields, the top rod and the expansion sleeve are located inside the housing; the closed end has a connecting hole at its center, through which the clamping claws pass and protrude outside the housing; the inner wall of the housing has a boss for restricting the axial rotation of the shield and the magnetic shield.

[0042] Specifically, the magnetic control assembly is disposed inside the housing 2, located between the switch assembly and the clamping assembly; the magnetic control assembly includes a magnet 41, a shielding frame 42 and two magnetic shields 43.

[0043] Please see Figure 7 This is a three-dimensional structural diagram of the shielding frame 42 provided by the present invention. The shielding frame 42 is U-shaped and includes two strip-shaped sidewalls 422 and a strip-shaped bottom wall 421; the two strip-shaped sidewalls 422 are parallel to each other, and the two ends of the strip-shaped bottom wall 421 are respectively connected to the bottom ends of the two strip-shaped sidewalls 422. The shielding frame 42 is made of an antiferromagnetic material, such as copper, aluminum, silicon oxide, graphite, etc., to shield the magnetic field lines emitted by the magnet 41.

[0044] Please also refer to Figures 8-9 ,in, Figure 8 This is a three-dimensional structural diagram of the magnetic shield provided by the present invention. Figure 9 for Figure 8 The diagram shows a front view of the magnetic shield. Two magnetic shields 43 are respectively disposed on both sides of the shielding frame 42, and together with the shielding frame 42, form a protective shell that encloses the bottom and sides of the magnet 41. Two magnetic platforms 431 are provided on the bottom surface of the magnetic shield 43 near the contact platform 61. The magnetic shield 43 is made of soft magnetic material, such as iron, iron-based alloys, or soft magnetic ferrite, to confine the magnetic field lines emitted by the magnet 41, causing a redistribution of the spatial magnetic field. The magnetic platforms 431 at its bottom further concentrate the magnetic field lines, enhancing the spatial magnetic field below the magnet 41.

[0045] Please see Figure 6This is a three-dimensional structural diagram of the magnet 41 provided by the present invention. The magnet 41 is disposed within the outer casing and is capable of rotating about its axial direction. The two magnetic poles of the magnet 41 are respectively oriented radially. Preferably, the magnet 41 has a rotationally symmetric structure; in one embodiment, the magnet 41 is a cylinder, and the outer casing has a cylindrical cavity. In other embodiments, the magnet 41 can also be a rotationally symmetric structure such as a sphere, frustum, cone, or strip, and the outer casing has a matching cavity. The magnet 41 is made of a material capable of generating a magnetic field. Preferably, the magnet 41 is a permanent magnet that is not easily demagnetized, such as a neodymium iron boron permanent magnet, a samarium cobalt permanent magnet, an alnico permanent magnet, or a ferrite permanent magnet. In some embodiments, the magnet 41 can also be an electromagnet, which generates a magnetic field through an external power supply.

[0046] The outer casing engages with the inner wall of the housing 1, allowing it to slide axially within the housing 1. The outer casing formed by the shielding frame 42 and the magnetic shield 43 engages with and is fixed to the housing 2 to restrict rotation, while still allowing it to slide axially within the housing 1. This ensures that the outer casing can only move axially along the housing 2 and cannot rotate synchronously with the magnet 41. In other words, when the magnet 41 rotates, its two magnetic poles face towards or away from the two strip-shaped sidewalls 422 of the shielding frame 42, redistributing the spatial magnetic field generated by the magnet 41. In one embodiment, the shielding frame 42 and the magnetic shield 43 are fixedly connected by bolts to form a cylindrical outer casing enclosing the magnet 41. The thickness of the sidewall of the magnetic shield 43 is greater than the thickness of the two strip-shaped sidewalls 422 of the shielding frame 42, forming a groove at the strip-shaped sidewalls 422 of the shielding frame 42, while the inner wall of the housing 2 has a corresponding boss. In other embodiments, the shielding frame 42 and the magnetic shield 43 can also be fixed together by welding, bonding, or tenon joints.

[0047] Specifically, please refer to Figures 3-5 The clamping assembly includes an expansion sleeve 6, a first compression spring 8, a second compression spring 7, and a push rod 5.

[0048] Please also refer to Figures 4-5 ,in, Figure 4 This is a three-dimensional structural diagram of the expansion sleeve provided by the present invention. Figure 5 for Figure 4 The diagram shows a front view of the expansion sleeve 6. The expansion sleeve 6 includes a claw 62 and an abutment platform 61. The end of the claw 62 protrudes from the housing 2, and the abutment platform 61 is located in the inner cavity of the housing 2 and fixed to the top of the claw 62.

[0049] Specifically, the pawl 62 includes a sleeve 621 and a locking platform 622 disposed at the end of the sleeve 621; the sleeve 621 is a tubular structure formed by multiple spring pieces, the top end of which is fixed to the locking platform 61, and the end end can be opened and closed by external force; the locking platform 622 is disposed on the outer wall of each spring piece and extends outward to form a hook-shaped structure, and the outer diameter of the locking platform 622 varies with the inner diameter of the end of the sleeve 621. When the end of the tubular structure is closed, the outer diameter of the locking platform 622 is smaller than the inner diameter of the pre-drilled hole 13. At this time, the sleeve 621 and the locking platform 622 on it can freely pass through the pre-drilled hole 13 on the aircraft wall panel (upper wall panel 11 and lower wall panel 12). When the end of the tubular structure is open, the outer diameter of the locking platform 622 is larger than the inner diameter of the pre-drilled hole 13. At this time, the locking platform 622 can hook onto the lower wall panel 12 of the aircraft, so that the upper wall panel 11 and the lower wall panel 12 of the aircraft are clamped between the locking platform 622 and the bottom surface of the shell 2.

[0050] An abutment platform 61 is disposed between the bottom surface of the housing 2 and the magnetic control assembly. It is made of a soft magnetic material, such as iron, iron-based alloys, or soft magnetic ferrite, and moves closer to or further away from the magnetic control assembly under the influence of a magnetic field. In one embodiment, the abutment platform 61 includes a first abutment portion 611 and a second abutment portion 612 with different heights, and the first abutment portion 611 is located inside the second abutment portion 612. A first compression spring 8 is disposed between the second abutment portion 612 and the bottom surface of the housing 2 and is sleeved on the outer periphery of the first abutment portion 611 and the sleeve 621. Its two ends abut against the second abutment portion 612 and the bottom surface of the housing 2, respectively. The rebound force generated when compressed provides a certain clamping force to the bottom surface of the housing 2. In the tightened state, any matched first compression spring 8 can adapt to changes in the thickness of the aircraft panel while providing a suitable clamping force, thus having a certain degree of universality. The second clamping spring 7 is disposed between the first abutment portion 612 and the magnetic control assembly and sleeved on the outer periphery of the push rod 5. Its two ends abut against the first abutment portion 612 and the magnetic control assembly, respectively, and its stiffness coefficient is greater than that of the first clamping spring 8. In the tightened state, the second clamping spring 7 further compresses the first clamping spring 8, thereby enhancing the clamping force on the bottom surface of the housing 2. During disassembly, the second clamping spring 7 can overcome part of the rebound force of the first clamping spring 8, allowing the push rod 5 to gradually disengage from the sleeve 621 and separating the push rod 5 from the sleeve 621. Furthermore, the first abutment portion 611 and the second abutment portion 612 facilitate the limiting of the first clamping spring 8 and the second clamping spring 7, ensuring uniform force distribution within the temporary fastener.

[0051] The top end of the push rod 5 is fixedly connected to the magnetic control assembly, specifically to the middle of the bottom surface of the strip-shaped bottom wall 421. Its end passes through the second compression spring 7 and the abutment platform 61 in sequence. Its axial displacement along the sleeve 621 causes the end of the sleeve 621 to open and close, thereby changing the outer diameter of the locking platform 622. When the claw 62 passes through the pre-drilled hole 13, the push rod 5 moves towards the end of the sleeve 621, and the inner diameter of the end of the tubular structure gradually increases until the outer diameter of the locking platform 622 is greater than the inner diameter of the pre-drilled hole 13. At this time, the locking platform 622 can hook onto the lower wall plate 12. The push rod 5 moves towards the top end of the sleeve 621, and the inner diameter of the end of the tubular structure gradually decreases until the outer diameter of the locking platform 622 is less than the inner diameter of the pre-drilled hole 13. At this time, the claw 62 can move freely within the pre-drilled hole 13.

[0052] Preferably, the magnet 41 has a rotationally symmetrical structure with its rotation axis coinciding with the axis of the top rod 5; the two magnetic poles of the magnet 41 are perpendicular to the axis of the top rod 5 and can rotate around the axis of the top rod 5. The shielding frame 42 is disposed between the magnet 41 and the top rod 5. Two side walls 422 are respectively disposed on both sides of the magnet 41 and parallel to the top rod 5. The bottom wall 421 is connected to the bottom ends of the two side walls 422 and is fixed perpendicularly to the top rod 5. The shielding frame 42 is in close contact with the bottom and side surfaces of the magnet 41, dividing the magnet 41 into two equal parts.

[0053] In a preferred embodiment, the housing 2 is a hollow cylindrical structure, including an open end and a closed end; the switch assembly is disposed at the open end of the housing 2, forming a cavity with the housing 2; a central hole is provided at the center of the closed end (i.e. the bottom surface of the housing 2), the end of the sleeve 621 passes through the central hole, and the snap-fit ​​platform 622 is exposed outside the housing 2.

[0054] Please see Figure 10 This is a three-dimensional structural diagram of the switch assembly provided by the present invention. The switch assembly includes a switch cover 31, a switch 32, and a skin 33. The switch cover 31 is a hollow cover-shaped structure, which is fixed to the top of the housing 2 by bolts 31a, and forms a cavity with the housing 2 to accommodate the clamping assembly and the magnetic control assembly; in other embodiments, the switch cover 31 can also be fixed to the top of the housing 2 by welding, gluing, or tenon joint connection, or the switch cover 31 and the housing 2 can be integrally formed.

[0055] The inner wall of the switch cover 31 is provided with two symmetrically distributed limiting walls 311. The limiting walls 311 include a first limiting wall 311a and a second limiting wall 311b that are staggered and connected to each other. The switch 32 is disposed inside the switch cover 31, and its outer periphery is provided with symmetrically distributed limiting protrusions 321. The switch 32 can be moved and rotated along the axial direction of the housing 2 by external force, so that the limiting protrusions 321 on it abut against the first limiting wall 311a or the second limiting wall 311b.

[0056] The switch 32 is fixed to the magnet 41 to drive the magnet 41 to rotate axially along the housing 2 and to drive the magnetic control assembly to move axially along the housing 2. Specifically, the switch 32 has a locking part 322 on its surface facing the magnet 41, which locks into the top surface of the magnet 41. In one embodiment, the locking part 322 is a boss, and the top surface of the magnet 41 has a groove corresponding to the boss. In other embodiments, the locking part is a groove, and the top surface of the magnet 41 has a boss corresponding to the groove. In addition, the switch 32 can also be fixed to the magnet 41 by bolting, welding, or gluing, as long as the function of driving the magnet 41 to perform axial displacement or rotation using the switch 32 can be achieved.

[0057] The skin 33, fixed to the top surface of the switch 32, is made of soft magnetic material and is used to control the axial movement and rotation of the switch 32 along the housing 2 via an external magnetic field. Preferably, both the switch cover 31 and the switch 32 are made of antiferromagnetic material to prevent magnetic field lines emitted by the magnet 41 from radiating above the magnet 41, which helps to enhance the spatial magnetic field on the side or below the magnet 41. In some embodiments, the switch assembly does not have a skin 33, but a handle is provided on the top surface of the switch 32 for controlling the axial displacement or rotation of the switch 32 by external force such as mechanical force. However, in practical applications, the load-bearing capacity required for temporary fasteners used in aircraft assembly is often large, and the drive method via the handle is only suitable for light-load situations, such as daily fastening needs for decoration and renovation.

[0058] Please also refer to Figure 11 and Figure 12 ,in, Figure 11 This is a magnetic field line distribution diagram of the magnetic control component provided in this embodiment in the first state. Figure 12 This is a diagram showing the magnetic field line distribution of the magnetic control component in the second state provided in this embodiment.

[0059] In the first state, the two magnetic poles of magnet 41 face the two side walls 422 of shielding frame 42 respectively. The magnetic field lines emitted by magnet 41 are conducted through the side wall of magnetic shield 43. That is, the magnetic field lines start from the north pole of magnet 41, pass through the side of magnetic shield 43 and return directly to the south pole of magnet 41. Due to the binding effect of magnetic shield 43 on the magnetic field lines, the spatial magnetic field generated by magnet 41 is only located on the side of magnet 41. There is no spatial magnetic field below magnet 41, so the magnetic control component has no magnetic attraction to the contact platform 61.

[0060] In the second state, both magnetic poles of magnet 41 are far from the two side walls 422 of shielding frame 42. At this time, the magnetic field lines of magnet 41 cannot be directly conducted through the side walls of magnetic shield 43. The magnetic field lines can only originate from the north pole of magnet 41, converge through the side walls of magnetic shield 43 to one of the magnetic platforms 431, and then sequentially pass through the other magnetic platform 431 and the other side wall of magnetic shield 43, returning to the south pole of permanent magnet 41. In other words, the spatial magnetic field generated by magnet 41 is located on the side and below magnet 41. Furthermore, because all magnetic field lines converge between the two magnetic platforms 431, a stronger spatial magnetic field exists below magnet 41, causing the magnetic control component to be firmly bonded to the contact platform 61 through magnetic attraction.

[0061] (1) The working principle of this magnetic conversion flexible temporary fastener during installation is as follows:

[0062] The upper panel 11 and lower panel 12 of the aircraft are stacked one on top of the other, and the pre-drilled holes 13 on the two panels are aligned. The magnetic conversion flexible temporary fastener is placed on the upper panel 11 of the aircraft, and the claw 62 is inserted into the pre-drilled hole 13. At this time, the magnetic control assembly is in the first state, and the limiting boss 321 of the switch 32 abuts against the first limiting wall 311a of the switch cover 31.

[0063] Pressing switch 32 causes the magnetic control assembly to move towards the bottom surface of housing 2, compressing the second clamping spring 7 until the magnetic guide platform 431 contacts the second abutment part 612, thereby compressing the first clamping spring 8. Since the stiffness coefficient of the second clamping spring 7 is greater than that of the first clamping spring 8, the first clamping spring 8 is further compressed, generating a greater rebound force. Simultaneously, driven by the magnetic control assembly, the push rod 5 is inserted into the sleeve 621, gradually increasing the inner diameter of the end of the sleeve 621 until the outer diameter of the locking platform 622 exceeds the inner diameter of the pre-drilled hole 13. At this point, the bottom surface of housing 2 is subjected to the rebound force of the first clamping spring 8, thereby providing a downward clamping force.

[0064] Rotate switch 32 until the limiting boss 321 of switch 32 abuts against the second limiting wall 311b of switch cover 31, and drive magnet 41 to rotate axially, so that the two magnetic poles of magnet 41 move away from the two side walls 422 of shield frame 42, that is, the magnetic control component switches from the first state to the second state, and the magnetic control component and the abutment platform 61 are firmly connected by magnetic attraction.

[0065] When switch 32 is released, under the elastic force of the first compression spring 8, the magnetic control assembly, push rod 5, expansion sleeve 6, and second compression spring 7 move as a whole towards switch cover 31 until the locking platform 622 at the end of sleeve 621 hooks onto the lower wall plate 12. Because there is still magnetic attraction between the magnetic control assembly and the locking platform 61, the second compression spring 7 remains compressed, preventing the push rod 5 from disengaging from the sleeve 621. This results in the outer diameter of the locking platform 622 being smaller than the inner diameter of the pre-drilled hole 13, thus preventing it from hooking onto the lower wall plate 12. At this time, due to the limiting effect of the limiting wall 311 of switch cover 31 and the elastic force of the second compression spring 7, the first compression spring 8 is still partially compressed. The resulting rebound force causes a downward pressing force on the bottom surface of housing 2 and an upward pressing force on the locking platform 622, thereby clamping the upper wall plate 11 and lower wall plate 12 between the bottom surface of housing 2 and the locking platform 622, achieving a temporary fastening effect.

[0066] (2) The working principle of this magnetic conversion flexible temporary fastener during disassembly is as follows:

[0067] Press switch 32 again to drive the magnetic control assembly, top rod 5, expansion sleeve 6, and second clamping spring 7 to move toward the bottom of housing 2. Then rotate switch 32 in the opposite direction so that the two magnetic poles of magnet 41 are respectively facing the two side walls 422 of shielding frame 42. At this time, the magnetic control assembly returns to the first state and the magnetic attraction between it and the abutment platform 61 disappears.

[0068] Releasing switch 32 causes the expansion sleeve 6 to spring back towards the switch cover 31 under the force of the first compression spring 8. Unlike the installation process, since there is no magnetic attraction between the magnetic control component and the abutment platform 61, the magnetic control component will also move towards the switch cover 31 under the force of the second compression spring 7, and drive the push rod 5 away from the expansion sleeve 6. Because the stiffness coefficient of the second compression spring 7 is greater than that of the first compression spring, the speed at which the push rod 5 moves towards the switch cover 31 is greater than the speed at which the expansion sleeve 6 moves towards the switch cover 31. Therefore, the push rod 5 can be gradually pulled out from inside the sleeve 621, and the inner diameter of the end of the sleeve 621 gradually decreases. When the forces acting on the second compression spring 7 and the first compression spring 8 are balanced, the push rod 5 is completely pulled out from the inside of the sleeve 621, the end of the sleeve 621 is in a closed state, the outer diameter of the locking platform 622 is smaller than the inner diameter of the pre-made hole 13, so the locking platform 622 cannot hook the lower wall plate 12, and the claw 62 can be moved out of the pre-made hole 13.

[0069] Compared with existing technologies, the present invention provides a magnetic conversion flexible temporary fastener that introduces a magnetic control component. The relative movement of the magnet and the shielding frame alters the spatial magnetic field generated by the magnet, thereby causing the magnetic control component to magnetically attract the abutment platform. This allows the push rod to be firmly inserted into the claw to maintain the fastening effect on the aircraft panel, simplifying the assembly process and improving the stability and safety of aircraft assembly. The magnetic concentrating effect of the magnetic guide cover further alters the distribution of the spatial magnetic field, thereby precisely controlling the magnetic attraction force of the magnetic control component on the abutment platform. Furthermore, the magnetic guide platform can converge magnetic field lines, enhancing the spatial magnetic field below the magnet, thus increasing the magnetic attraction force of the magnetic control component on the abutment platform. In addition, the use of compression springs with different stiffness coefficients facilitates adaptation to aircraft panels of varying thicknesses, further simplifying the assembly process. This temporary fastener has a simple overall structure, ingenious design, and stable clamping state, significantly improving the quality and efficiency of aircraft assembly.

[0070] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A magnetic conversion type flexible temporary fastener, characterized in that: Includes housing, switch assembly, magnetic control assembly, and clamping assembly; The switch assembly is disposed on the housing, and the switch assembly and the housing together form a receiving cavity; The magnetic control assembly is disposed within the housing, located between the switch assembly and the clamping assembly. The magnetic control assembly includes a magnet, an antiferromagnetic shielding frame, and two magnetically conductive covers. The shielding frame is U-shaped, comprising two strip-shaped sidewalls and a strip-shaped bottom wall. The two strip-shaped sidewalls are parallel to each other, and the two ends of the strip-shaped bottom wall are respectively connected to the bottom ends of the two strip-shaped sidewalls. The two magnetically conductive covers are respectively disposed on both sides of the shielding frame, and together with the shielding frame, form a protective outer shell enclosing the bottom and sides of the magnet. The protective outer shell is engaged with the inner wall of the housing and can slide axially within the housing. The magnet is disposed within the protective outer shell and can rotate axially, with its two magnetic poles pointing radially. The clamping assembly includes an expansion sleeve, a push rod, a first clamping spring, and a second clamping spring; the expansion sleeve includes a claw and a magnetically conductive abutment; wherein, the claw includes a sleeve and a clamping platform disposed at the end of the sleeve, the abutment platform being fixed to the top end of the sleeve; one end of the push rod is fixedly connected to the magnetic control assembly, and the other end of the push rod passes through the abutment platform and is inserted into the sleeve, and its axial movement along the sleeve causes the outer diameter of the clamping platform to change; the first clamping spring is located between the clamping platform and the abutment platform and is sleeved on the outer periphery of the sleeve; the second clamping spring is located between the abutment platform and the strip-shaped bottom wall and is sleeved on the outer periphery of the push rod; The switch assembly includes a switch; the surface of the switch facing the magnet has a locking part, which locks into the top surface of the magnet; the switch is used to drive the magnet to perform axial displacement or rotation.

2. The magnetic conversion flexible temporary fastener according to claim 1, characterized in that: The two magnetic shields are respectively provided with magnetic platforms on their bottom surfaces facing the contact platform.

3. The magnetic conversion flexible temporary fastener according to claim 1 or 2, characterized in that: The stiffness coefficient of the second compression spring is greater than that of the first compression spring.

4. The magnetic conversion flexible temporary fastener according to claim 3, characterized in that: The abutment platform includes a first abutment portion and a second abutment portion of different heights, with the first abutment portion located inside the second abutment portion; the first compression spring is located between the second abutment portion and the locking platform and is sleeved on the outer periphery of the first abutment portion and the sleeve; the push rod passes through the first abutment portion; the second compression spring is located between the first abutment portion and the strip-shaped bottom wall and is sleeved on the outer periphery of the push rod.

5. The magnetic conversion flexible temporary fastener according to claim 4, characterized in that: The switch assembly also includes a switch cover, which is a hollow cover-shaped structure. Its inner sidewall has two symmetrically distributed limiting walls. The limiting walls include a first limiting wall and a second limiting wall that are staggered and connected to each other. The switch is disposed on the inner side of the switch cover, and its outer periphery has symmetrically distributed limiting protrusions.

6. The magnetic conversion flexible temporary fastener according to claim 5, characterized in that: The switch assembly also includes a magnetically conductive skin, which is fixed to the top surface of the switch.

7. The magnetic conversion flexible temporary fastener according to claim 6, characterized in that: The sleeve is a tubular structure formed by multiple spring pieces; the snap-fit ​​platform is disposed on the outer wall of each spring piece and extends outward to form a hook-shaped structure.

8. The magnetic conversion flexible temporary fastener according to claim 7, characterized in that: The magnet is a rotationally symmetric structure with its rotation axis coinciding with the axis of the push rod; the two magnetic poles of the magnet are perpendicular to the axis of the push rod and can rotate around the axis of the push rod.

9. The magnetic conversion flexible temporary fastener according to claim 8, characterized in that: The shielding frame is fixedly connected to the two magnetic shields to form a cylindrical outer shell that encloses the magnet; the thickness of the sidewalls of the two magnetic shields is greater than the thickness of the two strip sidewalls of the shielding frame, and a groove is formed at the strip sidewall of the shielding frame, and the inner wall of the shell is provided with a boss corresponding to the groove.

10. The magnetic conversion flexible temporary fastener according to claim 9, characterized in that: The housing is a hollow cylindrical structure, including an open end and a closed end; the switch assembly is disposed at the open end of the housing, forming a cavity with the housing; a central hole is provided at the center of the closed end, the end of the sleeve passes through the central hole, and the snap-fit ​​platform is exposed outside the housing.

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