Mechanical telescopic supporting rod for aero-engine fan cover

Abstract

The invention relates to the technical field of aviation auxiliary equipment, and particularly discloses a mechanical telescopic supporting rod for an aero-engine fan cover, the mechanical telescopic supporting rod comprises an outer pipe, a limiting mechanism, an inner pipe and a lock catch, one end of the outer pipe is hinged to the inner wall of the fan cover through a hinge support, and the inner pipe is slidably arranged in the outer pipe and limited through the limiting mechanism; and a lock catch is arranged at one end of the inner pipe. The supporting rod can be automatically locked / unlocked, the rotating sleeve is rotated clockwise, the pressing block is driven to move along the guide groove, the elastic stop pin is extruded, automatic unlocking is achieved, and then the supporting rod stretches / retracts. When the rotating sleeve is rotated anticlockwise, the elastic stop pin loses extrusion force, the elastic stop pin is popped out, and when the rotating sleeve moves to a specific position, the elastic stop pin is clamped into the guide groove, so that the stay bar is locked at an extension position or a contraction position. According to the lock catch, unlocking or locking is achieved through reciprocating motion of the movable hook along the fixed hook, the structure is firmer and more reliable, meanwhile, automatic reset of the movable hook can be achieved, the unlocking efficiency is higher, and use is convenient.

Description

Technical Field

[0001] This invention relates to the field of aviation auxiliary equipment technology, and more specifically to a mechanical telescopic strut for an aircraft engine fan shroud. Background Technology

[0002] Aircraft engine fan shroud struts are used to support and secure the fan shroud in its deployed position, facilitating engine inspection, maintenance, and replacement. The struts must be entirely integrated within the engine fan shroud. This necessitates that the struts possess high reliability, high unlocking / extension efficiency, and small size.

[0003] Utility model patent application number 202222405702.0 discloses a mechanical telescopic strut for aircraft engine cowlings. Due to space and cost limitations, the strut extension distance is short, and the locking structure has poor reliability, making it somewhat difficult to use in applications with high fixation requirements, such as engine fan cowlings. Furthermore, the struts used in some aircraft models still require manual locking with pins, resulting in slow unlocking / locking and low efficiency.

[0004] Therefore, there is an urgent need for a longer, more reliable, and easier-to-use mechanical telescopic strut for aircraft engine fan housings. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a mechanical telescopic strut for aircraft engine fan shroud that is longer, more reliable and easier to use.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A mechanical telescopic strut for an aircraft engine fan shroud includes an outer tube, a limiting mechanism, an inner tube, and a latch. One end of the outer tube is hinged to the inner wall of the fan shroud via a hinge support. The inner tube is slidably disposed inside the outer tube and limited by the limiting mechanism. One end of the inner tube is provided with a latch. When the inner tube slides out of the outer tube, the latch can be locked to a locking pin on the fan shroud wall panel. The limiting mechanism can fix the inner tube and the outer tube.

[0007] As a further improvement to the above technical solution: The limiting mechanism includes a rotating sleeve sleeved on the outer tube and capable of rotating relative to the outer tube, a guide groove disposed on the outer tube, and an elastic stop pin elastically disposed on the inner tube radially. The inner wall of the rotating sleeve is fixedly provided with a pressure block, which is slidably installed in the guide groove. The rotation of the rotating sleeve can drive the pressure block to slide along the guide groove. The elastic stop pin can be elastically engaged in the guide groove; When the pressure block is slid along the guide groove to the position of the elastic stop pin by the rotating sleeve, the pressure block can push the elastic stop pin out of the guide groove; At least one set of the elastic retaining pins is provided at each end of the inner tube.

[0008] As a further improvement to the above technical solution: The guide groove is elongated and its length is set along the circumference of the outer tube.

[0009] As a further improvement to the above technical solution: The part of the elastic stop pin that contacts the pressure block has a dome surface, and the part of the pressure block that contacts the elastic stop pin has a slope surface that matches the dome surface. The end opening of the outer tube is a trumpet-shaped opening that matches the dome surface.

[0010] As a further improvement to the above technical solution: The pressure blocks are evenly distributed in multiple sets along the circumference of the inner wall of the rotating sleeve, and the multiple sets of pressure blocks are spaced apart along the axial direction of the rotating sleeve. The guide groove and the elastic stop pin are each set in a one-to-one correspondence with the pressure block.

[0011] As a further improvement to the above technical solution: The inner wall of the outer tube is provided with a sliding groove along the length of the outer tube. The sliding groove matches the elastic stop pin and is used to guide the inner tube.

[0012] As a further improvement to the above technical solution: The inner tube is provided with a stepped through hole for installing an elastic stop pin. The elastic stop pin is a stepped shaft pin and is elastically set in the stepped through hole by a spring.

[0013] As a further improvement to the above technical solution: The latch includes a fixed hook, a sliding sleeve, and a movable hook; The sliding sleeve is fitted outside the fixed hook and the movable hook, and can drive the movable hook to slide back and forth relative to the fixed hook; One end of the fixed hook is provided with a hook-shaped part that can hook onto the fan cover plate locking pin, and one end of the movable hook is provided with a strip-shaped part. When the strip-shaped part slides close to the hook-shaped part with the movable hook, the strip-shaped part can close with the hook-shaped part to lock the fan cover plate locking pin; when the strip-shaped part slides away from the hook-shaped part with the movable hook, the strip-shaped part can separate from the hook-shaped part to release the fan cover plate locking pin.

[0014] As a further improvement to the above technical solution: The fixed hook is provided with an elongated through hole, and the movable hook is provided with a sliding pin, which is slidably disposed in the elongated through hole.

[0015] As a further improvement to the above technical solution: The fixing hook is also provided with a guide post, and a compression spring is sleeved on the guide post; The movable hook is provided with a blind hole that matches the guide post; When the strip-shaped portion moves away from the hook-shaped portion, the guide post can be inserted into the blind hole, and the compression spring can compress and hold the fixed hook and movable hook at both ends.

[0016] Compared with the prior art, the advantages of the present invention are as follows: (1) A mechanical telescopic strut for an aircraft engine fan shroud, comprising an outer tube, a limiting mechanism, an inner tube, and a latch. One end of the outer tube is hinged to the inner wall of the fan shroud via a hinge support. The inner tube is slidably disposed within the outer tube and limited by the limiting mechanism. One end of the inner tube is provided with a latch. When the inner tube slides out of the outer tube, the latch can be locked to a locking pin on the fan shroud wall panel. The limiting mechanism includes a rotating sleeve sleeved on the outer tube and rotatable relative to the outer tube, a guide groove disposed on the outer tube, and an elastic stop pin radially disposed on the inner tube. A pressure block is fixedly disposed on the inner wall of the rotating sleeve. The pressure block is slidably installed in the guide groove. The rotation of the rotating sleeve can drive the pressure block to slide along the guide groove. The elastic stop pin can elastically engage with the guide groove. When the pressure block is slid along the guide groove to the position of the elastic stop pin by the rotating sleeve, the pressure block can push the elastic stop pin out of the guide groove. The support rod of this invention can be automatically locked / unlocked. Rotating the rotating sleeve clockwise causes the pressure block to move along the guide groove, squeezing the elastic stop pin and automatically unlocking it from the pressure block guide sleeve, thus extending / retracting the support rod. When the rotating sleeve is rotated counterclockwise, the elastic stop pin loses its compressive force and extends outward under the action of the built-in spring. When it reaches a specific position, it engages with the guide groove, thus locking the support rod in either the extended or retracted position.

[0017] (2) The locking mechanism of this support rod includes a sliding sleeve, a fixed hook, and a movable hook. The movable hook moves back and forth along the fixed hook to unlock or lock, making the structure more robust and reliable. At the same time, the movable hook can be automatically reset, making the unlocking efficiency higher and the use more convenient. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a mechanical telescopic strut for an aircraft engine fan shroud according to an embodiment of the present invention; Figure 2 for Figure 1 A cross-sectional view of a mechanical telescopic strut; Figure 3 for Figure 1 A partial sectional view of the outer tube of the mechanical telescopic strut; Figure 4 This is a sectional view of the limiting mechanism; Figure 5 for Figure 4Axial view of the middle limit mechanism without the rotating sleeve; Figure 6 This is a schematic diagram of the lock being exploded; Figure 7 This is a cross-sectional view of the latch.

[0019] Legend: 1. Outer tube, 1.1. Slide groove, 1.2. Trumpet-shaped opening, 1.3. Slide groove, 1.4. Cover; 2. Limiting mechanism, 2.1. Rotating sleeve, 2.2. Guide groove, 2.3. Elastic stop pin, 2.4. Pressure block, 2.5. Pressure block guide sleeve; 3. Inner tube; 4. Hinge support; 5. Lock, 5.1. Slide sleeve, 5.2. Movable hook, 5.3. Fixed hook, 5.4. Long strip through hole, 5.5. Sliding pin, 5.6. Guide post, 5.7. Compression spring, 5.8. Blind hole. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figures 1 to 7 As shown, this embodiment provides a mechanical telescopic strut for an aircraft engine fan shroud, including an outer tube 1, a limiting mechanism 2, an inner tube 3, and a locking buckle 5. The strut is normally in a retracted state and stored inside the fan shroud. (Referring to...) Figure 1 The left end of the outer tube 1 is hinged to the inner wall of the engine fan shroud via a hinge support. The inner tube 3 is slidably disposed inside the outer tube 1 and is limited by a limiting mechanism 2. One end of the inner tube 3 is provided with a latch 5. When the inner tube 3 slides out of the outer tube 1, the latch 5 can be locked to the locking pin of the fan shroud wall plate. The limiting mechanism 2 includes a rotating sleeve 2.1 sleeved on the outer tube 1 and rotatable relative to the outer tube 1, a guide groove 2.2 disposed on the outer tube 1, and a guide groove 2.2 elastically disposed radially along the inner tube 3 on the inner tube 3. The rotating sleeve 2.1 has an elastic stop pin 2.3; a pressure block 2.4 is fixedly provided on the inner wall of the rotating sleeve 2.1. The pressure block 2.4 is slidably installed in the guide groove 2.2. The rotating sleeve 2.1 can rotate the pressure block 2.4 to slide along the guide groove 2.2; the elastic stop pin 2.3 can elastically engage with the guide groove 2.2; when the rotating sleeve 2.1 drives the pressure block 2.4 to slide along the guide groove 2.2 to the position of the elastic stop pin 2.3, the elastic stop pin 2.3 can be pushed out of the guide groove 2.2.

[0022] See Figure 4 As a preferred option, for ease of processing and replacement, the guide groove 2.2 is provided by a pressure block guide sleeve 2.5 connected to the right end of the outer tube 1 shown in the figure. The pressure block guide sleeve 2.5 can be fixedly connected to the outer tube 1 as one unit. The rotating sleeve 2.1 is sleeved on the outside of the pressure block guide sleeve 2.5. The right end of the pressure block guide sleeve 2.5 and the rotating sleeve 2.1 shown in the figure is also provided with a cover 1.4.

[0023] In this embodiment, multiple sets of elastic stop pins 2.3 are provided at both ends of the inner tube 3. When the inner tube 3 is retracted into the outer tube 1, the elastic stop pin 2.3 at the right end of the diagram engages with the guide groove 2.2 located at the rightmost end of the outer tube 1, as shown in the diagram. Figure 2 As shown, when extended, the elastic stop pin 2.3 at the leftmost end of the inner tube 3 engages with the guide groove 2.2 at the rightmost end of the outer tube 1, thus limiting the extension and retraction of the inner tube 3. The guide groove 2.2 is elongated, and its length is along the circumference of the outer tube 1. Multiple sets of pressure blocks 2.4 are evenly distributed along the inner wall of the rotating sleeve 2.1, and these sets of pressure blocks 2.4 are spaced apart along the axial direction of the rotating sleeve 2.1; the guide groove 2.2 and the elastic stop pin 2.3 are each corresponding to one of the pressure blocks 2.4.

[0024] In this embodiment, the inner wall of the outer tube 1 is provided with a groove 1.3 along the length of the outer tube 1. Specifically, the groove 1.3 is a long tubular guide rail arranged axially along the outer tube 1. The guide rail is fixed inside the outer tube 1 by pins. The inner wall of the guide rail contains four straight grooves 1.3 along the axial direction (corresponding to the elastic stop pins 2.3). Figure 3 As shown, the chute 1.3 extends from the left end of the outer tube 1 to the rightmost end of the diagram, i.e., the cap 1.4, and connects to the outside. This guides the elastic stop pin 2.3 when the inner tube 3 extends or retracts. A flared opening is also provided, together forming a longitudinal limiting guide rail. Figure 4 As shown, the elastic stop pin 2.3 can be gradually and smoothly compressed and retracted by the flared opening when the inner tube 3 is retracted into the outer tube 1. When it slides into the guide groove 2.2, it can automatically limit its movement by being elastically locked into the guide groove 2.2.

[0025] The part of the elastic stop pin 2.3 that contacts the pressure block 2.4 has a domed surface, and the part of the pressure block 2.4 that contacts the elastic stop pin 2.3 has a ramp surface that matches the domed surface. The pressure block 2.4 is fixedly connected to the rotating sleeve 2.1 by a pin and has a clearance fit with the guide groove 2.2. The rotation of the rotating sleeve 2.1 can drive it to move circumferentially around the inner tube 3. The inner tube 3 has a stepped through hole for installing the elastic stop pin 2.3, with a smooth hole at the small end and a threaded hole at the large end. The elastic stop pin 2.3 is a stepped shaft pin and is elastically set in the stepped through hole by a spring. The large end of the shaft pin has a clearance fit with the threaded end and the small end of the stepped through hole, thus realizing the linear reciprocating motion of the elastic stop pin 2.3 along the radial direction of the inner tube 3. The elastic stop pin 2.3 is inserted from the threaded end and extends out from the light hole. When the extension reaches the designed stroke, it will be stuck by the step, forming a mechanical limit. Then a spring is placed and passed through the internal hexagonal pan head screw. At this time, the spring will be slightly pre-compressed, so that the spring has a certain compressive potential energy.

[0026] The latch 5 includes a fixed hook 5.3, a sliding sleeve 5.1, and a movable hook 5.2. The sliding sleeve 5.1 is fitted over the fixed hook 5.3 and the movable hook 5.2, and can drive the movable hook 5.2 to slide back and forth relative to the fixed hook 5.3. One end of the fixed hook 5.3 has a hook-shaped part that can hook onto the fan shroud panel locking pin, and one end of the movable hook 5.2 has a strip-shaped part. When the strip-shaped part slides close to the hook-shaped part with the movable hook 5.2, the strip-shaped part can close with the hook-shaped part to lock the fan shroud panel locking pin. When the strip-shaped part slides away from the hook-shaped part with the movable hook 5.2, the strip-shaped part can separate from the hook-shaped part to release the fan shroud panel locking pin. The fixed hook 5.3 has an elongated through hole 5.4, and the movable hook 5.2 has a sliding pin 5.5, which is slidably disposed within the elongated through hole 5.4.

[0027] Reference Figure 6 As shown, the left end opening of the sliding sleeve 5.1 is circular, and the right end opening is flat. The fixing hook 5.3 is located inside the sliding sleeve 5.1 and is arranged axially. Its hook-shaped part extends out through the strip-shaped opening end of the sliding sleeve 5.1, wherein the strip-shaped opening of the sliding sleeve 5.1 plays a guiding role, allowing it to make linear reciprocating motion along the fixing hook 5.3 rather than rotating.

[0028] The movable hook 5.2 is built into the fixed hook 5.3, and the movable hook 5.2 is fixedly connected to the sliding sleeve 5.1 by the sliding pin 5.5, that is, the sliding sleeve 5.1 and the movable hook 5.2 can be linked. The fixed hook 5.3 is also provided with a guide post 5.6, and a compression spring 5.7 is sleeved on the guide post 5.6; the movable hook 5.2 is provided with a blind hole 5.8 that matches the guide post 5.6; when the strip-shaped part is away from the hook-shaped part, the guide post 5.6 can be inserted into the blind hole 5.8, and the compression spring 5.7 can compress and hold the fixed hook 5.3 and the movable hook 5.2 at both ends.

[0029] The guide post 5.6 is horizontally embedded in the fixed hook 5.3, and its cylindrical part can be inserted into the blind hole 5.8 of the movable hook 5.2. Two compression springs 5.7 are sleeved on the two cylinders, one end abutting against the fixed hook 5.3 and the other end abutting against the movable hook 5.2, realizing the automatic reset of the movable hook 5.2. The guide post 5.6 is fastened to the fixed hook 5.3 by slotted pan head screws.

[0030] The specific method of using the strut in this embodiment is as follows: Unlocking procedure: The operator holds the sliding sleeve 5.1 and slides it axially backward. At this time, the sliding sleeve 5.1, through the sliding pin 5.5, drives the movable hook 5.2 to move backward together, compressing the compression spring 5.7 and unlocking the latch 5. The strut latch 5 can then be unlocked from the fan shroud panel locking pin. Releasing the sliding sleeve 5.1 causes the compression spring 5.7 to automatically extend and reset according to its elastic force, pushing the movable hook 5.2, the sliding sleeve 5.1, and the sliding pin 5.5 to automatically reset together.

[0031] Locking and unlocking are simply the reverse operations.

[0032] Elongation operation: Before elongation, the inner tube 3 retracts into the outer tube 1, and the elastic stop pin 2.3 at the far right end of the inner tube 3 diagram is stuck in the guide groove 2.2.

[0033] At this point, the operator holds the rotating sleeve 2.1 and rotates it clockwise, causing the four pressure blocks 2.4 to rotate clockwise. After rotating to a certain angle, the four pressure blocks 2.4, which are arranged in a four-way staggered manner, begin to simultaneously contact and press the four elastic stop pins 2.3 at the right end of the diagram, causing the four compression springs 5.7 behind them to begin to be compressed. Continue rotating until the pressure blocks 2.4 completely press the elastic stop pins 2.3 into the pressure block guide sleeve 2.5, and the compression springs 5.7 behind them reach their maximum compression. At the same time, the pressure blocks 2.4 also move to the end of the stroke of the guide groove 2.2 of the pressure block guide sleeve 2.5, where they are stuck and cannot continue to rotate clockwise.

[0034] Then, the inner tube 3 is manually dragged outward. At the instant the elastic stop pin 2.3 misaligns with the four slots of the pressure block guide sleeve 2.5, the compression spring 5.7 releases its compression. Simultaneously, the elastic stop pin 2.3 located inside the outer tube 1, i.e., the leftmost elastic stop pin 2.3 in the diagram of the inner tube 3, elastically contacts the sliding groove 1.3 on the inner wall of the outer tube 1, restricting the rotation of the inner tube 3. The support rod can only extend axially and cannot rotate. As the support rod continues to extend until the rightmost elastic stop pin 2.3 in the diagram disengages from the flared opening of the cap 1.4, the elastic stop pins 2.3 at both ends simultaneously guide and limit the rotation of the inner tube 3, maintaining its stability. When the four elastic stop pins 2.3 at the rightmost end in the diagram are fully extended, the compression spring 5.7 releases most of its compression. At this point, the rotation of the inner tube 3 is restricted only by the cooperation of the four elastic stop pins 2.3 at the leftmost end in the diagram and the sliding groove 1.3.

[0035] When the strut extends to the designed length, that is, when the four elastic stop pins 2.3 at the far left end of the diagram and the four guide grooves 2.2 of the pressure block guide sleeve 2.5 are at the same horizontal position, the four compression springs 5.7 simultaneously release their compressive potential energy, pushing the corresponding elastic stop pins 2.3 to extend along the guide grooves 2.2, directly pressing and pushing the pressure block 2.4 to rotate counterclockwise, and then locking into the guide grooves 2.2 of the pressure block guide sleeve 2.5, thus achieving automatic locking after the strut extends to the designed length.

[0036] When contracting, simply reverse the operation compared to stretching.

[0037] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the inventive concept should also be considered within the scope of protection of the present invention.

Claims

1. A mechanical telescopic strut for an aircraft engine fan shroud, characterized in that, Includes an outer tube (1), a limiting mechanism (2), an inner tube (3), and a latch (5). One end of the outer tube (1) is hinged to the inner wall of the fan cover via a hinge support (4). The inner tube (3) is slidably disposed inside the outer tube (1) and limited by the limiting mechanism (2). One end of the inner tube (3) is provided with a latch (5). When the inner tube (3) slides out of the outer tube (1), the latch (5) can be locked to the locking pin of the fan cover wall panel. The limiting mechanism (2) can fix the inner tube (3) and the outer tube (1).

2. A mechanical telescopic strut for an aircraft engine fan shroud according to claim 1, characterized in that, The limiting mechanism (2) includes a rotating sleeve (2.1) sleeved on the outer tube (1) and capable of rotating relative to the outer tube (1), a guide groove (2.2) provided on the outer tube (1), and an elastic stop pin (2.3) elastically provided on the inner tube (3) radially. The inner wall of the rotating sleeve (2.1) is fixedly provided with a pressure block (2.4), which is slidably installed in the guide groove (2.2). The rotation of the rotating sleeve (2.1) can drive the pressure block (2.4) to slide along the guide groove (2.2). The elastic stop pin (2.3) can be elastically engaged in the guide groove (2.2); When the rotating sleeve (2.1) drives the pressure block (2.4) to slide along the guide groove (2.2) to the position of the elastic stop pin (2.3), the pressure block (2.4) can push the elastic stop pin (2.3) out of the guide groove (2.2). The elastic stop pins (2.3) are provided at least once at each end of the inner tube (3).

3. A mechanical telescopic strut for an aircraft engine fan shroud according to claim 2, characterized in that, The guide groove (2.2) is elongated and its length is set along the circumference of the outer tube (1).

4. A mechanical telescopic strut for an aircraft engine fan shroud according to claim 3, characterized in that, The part of the elastic stop pin (2.3) that contacts the pressure block (2.4) has a dome surface, and the part of the pressure block (2.4) that contacts the elastic stop pin (2.3) has a slope surface that matches the dome surface; The end opening of the outer tube (1) is a trumpet-shaped opening (1.2) that matches the dome surface.

5. A mechanical telescopic strut for an aircraft engine fan shroud according to claim 4, characterized in that, Multiple sets of pressure blocks (2.4) are evenly distributed along the inner wall of the rotating sleeve (2.1), and the multiple sets of pressure blocks (2.4) are spaced apart along the axial direction of the rotating sleeve (2.1); The guide groove (2.2) and the elastic stop pin (2.3) are each set in a one-to-one correspondence with the pressure block (2.4).

6. A mechanical telescopic strut for an aircraft engine fan shroud according to claim 5, characterized in that, The inner wall of the outer tube (1) is provided with a groove (1.3) along the length of the outer tube (1). The groove (1.3) matches the elastic stop pin (2.3) and is used to guide the inner tube (3).

7. A mechanical telescopic strut for an aircraft engine fan shroud according to claim 2, characterized in that, The inner tube (3) is provided with a stepped through hole for installing an elastic stop pin (2.3). The elastic stop pin (2.3) is a stepped shaft pin and is elastically set in the stepped through hole by a spring.

8. A mechanical telescopic strut for an aircraft engine fan shroud according to any one of claims 2-7, characterized in that, The latch (5) includes a fixed hook (5.3), a sliding sleeve (5.1), and a movable hook (5.2); The sliding sleeve (5.1) is fitted over the fixed hook (5.3) and the movable hook (5.2), and can drive the movable hook (5.2) to slide back and forth relative to the fixed hook (5.3); One end of the fixed hook (5.3) is provided with a hook-shaped part that can hook the fan cover wall panel locking pin, and one end of the movable hook (5.2) is provided with a strip-shaped part. When the strip-shaped part slides close to the hook-shaped part with the movable hook (5.2), the strip-shaped part can close with the hook-shaped part to lock the fan cover wall panel locking pin; when the strip-shaped part slides away from the hook-shaped part with the movable hook (5.2), the strip-shaped part can separate from the hook-shaped part to release the fan cover wall panel locking pin.

9. A mechanical telescopic strut for an aircraft engine fan shroud according to claim 8, characterized in that, The fixed hook (5.3) is provided with an elongated through hole (5.4), and the movable hook (5.2) is provided with a sliding pin (5.5). The sliding pin (5.5) is slidably disposed in the elongated through hole (5.4).

10. A mechanical telescopic strut for an aircraft engine fan shroud according to claim 9, characterized in that, The fixing hook (5.3) is also provided with a guide post (5.6), and a compression spring (5.7) is sleeved on the guide post (5.6). The movable hook (5.2) is provided with a blind hole (5.8) that matches the guide post (5.6); When the strip-shaped portion moves away from the hook-shaped portion, the guide post (5.6) can be inserted into the blind hole (5.8), and the compression spring (5.7) can compress and hold the fixed hook (5.3) and movable hook (5.2) at both ends.

Images