Self-releasing lock

Abstract

This utility model relates to the field of lock technology and discloses a self-spring lock, including a lock box, a latch assembly, a square latch assembly, and a trigger assembly. The latch assembly includes a latch, a fixing block, a first spring, and a slider, with the fixing block fixed between the latch and the slider. The square latch assembly includes a square latch, a second spring, and a square latch plate slidably disposed within the lock box, with a locking groove formed on the side of the square latch plate. The trigger assembly includes a first lever, a locking plate, and a third spring. The locking plate is rotatably disposed within the lock box, with a locking pin formed on one side that can be embedded in the locking groove, and the first lever rotatably disposed on the other side. The first lever has a lever portion formed on the side near the latch assembly, and the other side is connected to the third spring, which is connected to the first lever so that the side of the lever portion abuts against the fixing block. When the front end of the lever portion is between the slider and the fixing block, the front end extends into the path of the slider sliding outward. This self-spring lock has a simple structure, few parts, is less prone to failure, and has a low manufacturing cost.

Description

Technical Field

[0001] This utility model relates to the field of lock technology, specifically to a self-springing lock. Background Technology

[0002] The main characteristic of a self-locking lock is that it locks upon closing the door. The lock body is equipped with a bolt assembly, a latch assembly, and a trigger assembly. During the locking process, as the bolt retracts into the lock housing and then pops out into the latch box, the trigger assembly is activated to release the latch assembly, allowing the latch to extend and lock the door. Furthermore, after unlocking, the lock needs to remain in the unlocked state, meaning only the bolt is allowed to extend from the lock housing, while the latch remains locked. However, in existing technologies, self-locking locks that achieve these functions have complex structures, numerous parts, and high production costs. Utility Model Content

[0003] This invention was made to solve the above-mentioned technical problems, and its purpose is to provide a self-locking mechanism with a relatively simple structure and low production cost.

[0004] According to one embodiment of the present invention, a self-locking lock is provided, including a lock housing and a latch assembly, a square latch assembly, and a trigger assembly therein; the latch assembly includes a latch, a fixing block, a first spring, and a slider slidably disposed within the lock housing connected to the latch; the fixing block is fixed between the latch and the slider; the first spring applies an outward force to the latch; the square latch assembly includes a square latch, a second spring, and a square latch plate slidably disposed within the lock housing; the side of the square latch plate has a locking groove; the second spring applies an outward force to the square latch plate; the trigger assembly includes... A first paddle, a locking plate, and a third spring are provided. The locking plate is rotatably disposed within the lock housing. One side of the locking plate has a locking post that can be embedded in the locking groove, and the other side has the first paddle rotatably disposed thereon. The first paddle has a toggle part on the side near the latch assembly, and the other side is connected to the third spring. The third spring applies a force to the first paddle, causing the side of the toggle part to abut against the fixing block and causing the locking post to be embedded in the locking groove. When the front end of the toggle part is between the slider and the fixing block, the front end extends into the path on which the slider slides outward.

[0005] In one embodiment, a second lever is rotatably provided inside the lock box. The outer periphery of the second lever extends outward to form a clearance protrusion and a lever head. The distance between one side of the clearance protrusion and the rotation center of the second lever is less than the distance between the other side of the clearance protrusion and the rotation center. The lever head abuts against the outer side of the slider. A clearance plate is formed on the other side of the first lever, abutting against the outer periphery of the second lever. When the second lever rotates and retracts the oblique tongue, the clearance plate moves from one side of the clearance protrusion to the other side, the first lever rotates, and the front end of the lever moves outward from the path of the slider.

[0006] In one embodiment, a third lever is rotatably provided inside the lock box, and a first sliding groove and a first lever are formed on the third lever; a second connecting rod is hinged to the second lever, and a second sliding groove is formed on the second connecting rod, and the first lever is slidably disposed in the second sliding groove; a second lever is formed on the square tongue plate and is slidably disposed in the first sliding groove.

[0007] In one embodiment, a third lever is formed on the third lever; the second spring is a torsion spring, one end of which is fixed inside the lock box, and the other end of which abuts against the third lever.

[0008] In one embodiment, a limiting post is fixedly provided inside the lock box; the side of the locking piece extends outward to form a first limiting part and a second limiting part respectively disposed on both sides of the limiting post.

[0009] In one embodiment, the second paddle has an arc-shaped third groove fitted onto the limiting post.

[0010] In one embodiment, the third spring is a tension spring, with one end connected to the limiting post and the other end connected to the relief plate.

[0011] In one embodiment, a limiting post is formed on the locking piece; an arc-shaped fourth sliding groove is formed in the lock box for the limiting post to slide in, or a first limiting part and a second limiting part are formed in the lock box on both sides of the limiting post.

[0012] In one embodiment, one side of the square tongue plate is an inclined guide surface, which is located on the side of the locking groove away from the square tongue. When the square tongue extends out of the lock box, the guide surface is opposite to the locking post.

[0013] Based on the above description and practice, when the self-spring lock of this utility model is applied to a door lock, it utilizes a first spring and a second spring to automatically eject and lock the latch and square bolt respectively under specific conditions. Through a trigger component located inside the lock housing, when the self-spring lock is in the open state, the latch is pressed into the lock housing by the pressure of the door frame when the door is closed. Simultaneously, the slider moves inward, and the front end of the actuating part is positioned between the fixed block and the slider. At this time, the front end of the actuating part extends to the path of the slider's outward sliding under the action of the third spring. When the door is closed, the latch moves outward under the force of the first spring, and the slider moves outward simultaneously. The outer side abuts against the front end of the actuating part, overcoming the force of the third spring, and pushes the actuating part outward, causing the locking plate to rotate. The locking pin on the locking plate moves out of the locking groove, releasing the limiting position of the square bolt plate. Under the action of the second spring, the square bolt plate moves outward, achieving locking. When closing the door, only the door leaf needs to be moved; no additional operation of the self-spring lock is required to achieve automatic locking. Furthermore, the self-locking mechanism has a relatively simple structure, fewer parts, is less prone to malfunctions during use, and has a low production cost. Attached Figure Description

[0014] Figures 1 to 5 This is a schematic diagram of the internal structure of the self-locking lock in one embodiment of the present invention when it is automatically locked, wherein the second lever and the second linkage are omitted.

[0015] Figures 6 to 8 This is a schematic diagram of the internal structure of the self-locking lock in one embodiment of the present invention when it is unlocked by the second lever.

[0016] The attached figures are labeled as follows:

[0017] 1. Lock box; 11. Limiting post; 21. Slanted tongue; 22. First connecting rod; 23. Fixing block; 24. First spring; 25. Sliding block; 31. Square tongue; 32. Second spring; 33. Square tongue plate; 34. Locking groove; 35. Second lever; 36. Guide surface; 41. First lever; 42. Locking piece; 43. Third spring; 44. Locking post; 45. Actuating part; 46. Relief plate; 47. First limiting part; 48. Second limiting part; 51. Second lever; 52. Relief protrusion; 53. Lever; 54. Third slide groove; 61. Third lever; 62. First slide groove; 63. First lever; 64. Second connecting rod; 65. Second slide groove; 66. Third lever. Detailed Implementation

[0018] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0019] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. It should be noted that in this disclosure, the terms "comprising," "configured with," and "set in" are used to indicate an open-ended inclusion, meaning that additional elements / components / etc. may exist besides those listed; the terms "first," "second," etc., are used only as labels and are not intended to limit the number or order of objects; the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0020] Unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] According to one embodiment of the present invention, a self-locking mechanism is provided, which is described below in conjunction with... Figures 1 to 8 The self-locking mechanism is explained using its application on doors as an example.

[0022] exist Figures 1 to 5 In order to demonstrate the structure and principle of the triggering component, the second paddle 51 and the second linkage 64 are omitted. Figure 1 When the self-locking lock shown is in the open state, the oblique tongue 21 extends out of the lock box 1, and the square tongue 31 is located inside the lock box 1. At this time, the front end of the toggle part 45 is located to the right of the slider 25. Figure 2The self-spring lock shown is in the state where the latch 21 is pressed into the lock box 1 by the door frame when the door is closed. At this time, under the action of the third spring 43, the front end of the toggle part 45 is between the slider 25 and the fixed block 23, and the front end of the toggle part 45 extends to the path of the slider 25 sliding to the left. Figure 3 In the self-spring lock shown, under the action of the first spring 24, the slider 25 and the tongue 21 slide outward (i.e. slide to the left in the figure), and the side of the slider 25 begins to push the front end of the actuating part 45 to move to the left, thereby causing the locking piece 42 to start to rotate counterclockwise. Figure 4 In the self-spring lock shown, the slanted tongue 21 moves to the outside of the lock box 1, the locking pin 44 moves out of the locking groove 34, and releases the limiting position of the opposite tongue plate 33. As the fixed block 23 pushes and the locking piece 42 rotates, the front end of the toggle part 45 also gradually moves to the outside of the slider 25 (lower side in the figure). Figure 5 In the self-locking mechanism, the square latch 31 and square latch plate 33 move outside the lock box 1 under the action of the second spring 32, completing the locking. The front end of the actuating part 45 also moves to the inside of the slider 25 (right side in the figure) due to the push of the fixing block 23 and the rotation of the locking piece 42, thus returning to its original position. Figure 1 The state of the central toggle unit 45.

[0023] The self-locking mechanism in this embodiment mainly includes a lock box 1 and its internal bolt assembly, square bolt assembly, and trigger assembly. The lock box 1 has a bolt hole on its side for the bolt 21 and square bolt 31 to extend out.

[0024] The latch assembly includes a latch 21, a fixing block 23, a first spring 24, and a slider 25. The fixing block 23 is fixed inside the lock housing 1 and located between the latch 21 and the slider 25. The latch 21 and the slider 25 are connected together. The slider 25 is slidably disposed inside the lock housing 1, and the first spring 24 applies an outward force to the latch 21. When no external force is applied, the latch 21 is pushed outside the lock housing 1 by the first spring 24.

[0025] In this embodiment, to improve the stability of the tongue assembly, the tongue 21 and the slider 25 are connected together via the first connecting rod 22. In other embodiments, the lengths of the tongue 21 and / or the slider 25 may be increased so that they are directly connected together.

[0026] Furthermore, in this embodiment, the first connecting rod 22 passes through the fixed block 23. When the latch 21 extends or retracts, the first connecting rod 22 slides back and forth in the fixed block 23, which can further improve the stability of the latch assembly. Further, in this embodiment, the first spring 24 is a compression spring, which is sleeved on the first connecting rod 22, with its two ends abutting against the fixed block 23 and the latch 21 respectively. When the latch 21 is pressed and moves into the lock box 1, or when the user actively operates the latch 21 to move into the lock box 1, the compression force of the first spring 24 increases. After the latch assembly loses external force, the latch 21 is ejected out of the lock box 1 by the first spring 24.

[0027] The latch assembly includes a latch 31, a second spring 32, and a latch plate 33 slidably disposed within the lock housing 1. The latch 31 and the latch plate 33 are connected together. A locking groove 34 is formed on the side of the latch plate 33. The second spring 32 applies an outward force to the latch plate 33. When the latch 31 and the latch plate 33 are not subjected to external force, the second spring 32 can push them outward to achieve locking.

[0028] The triggering assembly includes a first lever 41, a locking plate 42, and a third spring 43. The locking plate 42 is rotatably disposed within the lock housing 1. One side of the locking plate 42 has a locking pin 44 that can be embedded in the locking groove 34, and the other side has the first lever 41 rotatably disposed thereon. The rotation path of the locking pin 44 is fixed. When the square tongue 31 retracts into the lock housing 1, the locking groove 34 on the square tongue plate 33 is located on the rotation path of the locking pin 44.

[0029] The middle part of the first lever 41 is rotatably connected to the upper side of the locking plate 42. The side of the first lever 41 near the latch assembly has a lever part 45, and the other side is connected to the third spring 43. The third spring 43 applies a force to the first lever 41, forming a counterclockwise torque on the lever part 45, so that the lever part 45 can rotate counterclockwise in the figure. Then, when the lever part 45 is not subjected to external force, the side of the lever part 45 abuts against the fixing block 23. The force of the third spring 43 also forms a clockwise torque on the locking plate 42. If the square latch 31 is in the lock box 1 at this time, the locking pin 44 will be embedded in the locking groove 34, realizing the limiting and locking of the square latch assembly.

[0030] When the door is open, the internal structure of the self-locking mechanism is as follows: Figure 1As shown. During the closing process, the latch 21 is gradually moved into the lock box 1 by the pressure of the door frame, and the slider 25 moves inward at the same time. The front end of the actuating part 45 gradually moves from the right side of the slider 25 to between the fixed block 23 and the slider 25. At this time, the front end of the actuating part 45 extends into the path of the slider 25 sliding outward under the action of the third spring 43. When the door is closed, the latch 21 moves outward under the action of the first spring 24, and the slider 25 moves outward at the same time. The outer side of the slider 25 abuts against the front end of the actuating part 45, and after overcoming the action of the third spring 43, pushes the actuating part 45 to move outward at the same time, causing the locking plate 42 to rotate counterclockwise. The locking pin 44 on it moves out of the locking groove 34, releasing the limit of the square latch plate 33. The square latch plate 33 drives the square latch 31 to move outward under the action of the second spring 32, realizing the locking. During the entire closing process, the user only needs to move the door leaf and does not need to operate the self-locking mechanism to achieve automatic locking. Furthermore, the self-locking mechanism has a relatively simple structure, fewer parts, is less prone to malfunctions during use, and has a low production cost.

[0031] It should be noted that in other embodiments, the fixing block 23 may not be connected to the first connecting rod 22, but may be fixedly disposed between the tongue 21 and the slider 25, with the side of the actuating part 45 abutting against the fixing block 23, which can also achieve the above-mentioned automatic locking function.

[0032] In one embodiment, a second lever 51 is rotatably provided inside the lock box 1. A clearance protrusion 52 and a lever head 53 extend outward from the outer periphery of the second lever 51. The distance between one side of the clearance protrusion 52 and the rotation center of the second lever 51 is less than the distance between the other side of the clearance protrusion 52 and the rotation center. The lever head 53 abuts against the outer surface of the slider 25. A clearance plate 46 abuts against the outer periphery of the second lever 51 is formed on the other side (lower side in the figure). When the second lever 51 rotates and retracts the tongue 21, the clearance plate 46 moves from one side of the clearance protrusion 52 to the other side, the first lever 41 rotates, and the front end of the actuating part 45 moves outward from the path along which the slider 25 slides.

[0033] Specifically, the second lever 51 is usually linked to the handle on the lock (not shown in the figure), and the user can manually turn the second lever 51 when turning the handle. Figures 6 to 8 The internal structure of the self-spring lock changes when unlocked by the second lever 51. Figure 6 The structure shown is the initial state; Figure 7 The second lever 51 rotates clockwise to retract the latch 21 into the lock box 1, corresponding to the unlocking operation; Figure 8The second lever 51 rotates counterclockwise to return to its initial state, corresponding to the release of the handle after unlocking. When the second lever 51 rotates clockwise, its lever head 53 moves to the right in the diagram, causing the slider 25 and the latch 21 to move to the right, thus releasing the latch 21 from its lock. Simultaneously, the clearance protrusion 52 on the second lever 51 rotates, and the clearance plate 46 moves relative to the outer circumference of the second lever 51, from the upper side to the lower side of the clearance protrusion 52. Figures 6 to 7 The state shown is as follows. Because the distance between the upper side of the clearance protrusion 52 and the rotation center of the second lever 51 is less than the distance between the lower side of the clearance protrusion 52 and the rotation center of the second lever 51, during this process, the second lever 51 can drive the first lever 41 to rotate clockwise. Correspondingly, the front end of the actuating part 45 will also move downwards and will not be on the path of the slider 25 sliding outwards. Subsequently, after releasing the handle, the second lever 51 returns to its original position. Figure 6 In the indicated state, the oblique tongue 21 and the slider 25 slide outward synchronously, without causing the actuating part 45 to slide outward, and the locking pin 44 will not move out of the locking groove 34, so there is no situation where the opposite tongue plate 33 is limited.

[0034] In other words, in this embodiment, the self-locking latch can automatically release the limit of the opposite tongue plate 33 only when the latch 21 is compressed back into the lock box 1 and then extends out again during the closing process, thereby realizing the automatic locking of the square tongue 31; during the user's active unlocking process, although the latch 21 also retracts into the lock box 1 and then extends out again, it will not release the limit of the opposite tongue plate 33, and the square tongue 31 can remain locked in the lock box.

[0035] Furthermore, in this embodiment, a third lever 61 is rotatably provided inside the lock box 1, and a first sliding groove 62 and a first lever 63 are formed on the third lever 61; a second connecting rod 64 is hinged to the second lever 51, and a second sliding groove 65 is formed on the second connecting rod 64, and the first lever 63 is slidably disposed in the second sliding groove 65; a second lever 35 is formed on the square tongue plate 33 and is slidably disposed in the first sliding groove 62.

[0036] like Figures 6 to 8 As shown, the pivot of the third lever 61 is fixed in the lock housing 1, and the square tongue plate 33 is slidably connected to the pivot. When the second lever 51 rotates clockwise, the second connecting rod 64 moves upward, and the second sliding groove 65 drives the first lever 63 to move upward. Correspondingly, when the third lever 61 rotates clockwise, the first sliding groove 62 pushes the second lever 35 to move to the right, thereby retracting the square tongue plate 31 into the lock housing 1, thus completing the unlocking. At this time, the locking groove 34 is on the rotation path of the locking pin 44, and the locking pin 44 is embedded in the locking groove 34 under the force of the third spring 43, thereby locking and limiting the square tongue plate 33.

[0037] In this embodiment, a third lever 66 is formed on the third lever 61; the second spring 32 is a torsion spring, one end of which is fixed inside the lock box 1, and the other end rests against the third lever 66. Figure 8 As shown, after the square tongue 31 retracts into the lock box 1, the second spring 32 is under compression, and the force it exerts on the third lever 66 forms a counterclockwise torque. When the square tongue plate 33 is not restricted, the third lever 61 rotates counterclockwise, which can push the square tongue 31 to move outward, thus completing the locking.

[0038] In other embodiments, the second spring 32 can also act directly on the square tongue 31 or the square tongue plate 33, and can also complete the locking action when the square tongue plate 33 is not restricted.

[0039] In one embodiment, a limiting post 11 is fixedly provided inside the lock box 1; the side of the locking piece 42 extends outward to form a first limiting part 47 and a second limiting part 48 respectively disposed on both sides of the limiting post 11. Figure 4 and Figure 5 As shown, when the locking piece 42 rotates in both directions, the first limiting part 47 and the second limiting part 48 respectively abut against the two sides of the limiting post 11, which can limit the rotation amplitude of the locking piece 42 in both directions and prevent the triggering component from failing due to the large rotation of the locking piece 42.

[0040] Furthermore, in this embodiment, the second lever 51 has an arc-shaped third groove 54 that fits onto the limiting post 11. For example... Figures 6 to 8 As shown, when the second paddle 51 rotates, the limiting post 11 slides relative to it in the third slide groove 54. On the one hand, this can limit the forward and reverse rotation amplitude of the second paddle 51, and on the other hand, it can also improve the stability of the second paddle 51 when it operates in the lock box 1.

[0041] Furthermore, in this embodiment, the third spring 43 is a tension spring, such as... Figure 5 As shown, one end of the third spring 43 is connected to the limiting post 11, and the other end is connected to the relief plate 46. When the third spring 43 is stretched, if there is no external force, it can drive the actuating part 45 to rotate counterclockwise, and drive the locking piece 42 to rotate clockwise.

[0042] In other embodiments, the first spring 24, the second spring 32, and the third spring 43 can be selected from compression springs, tension springs, and torsion springs. By simply adjusting their positions, they can also perform the corresponding functions of the aforementioned springs.

[0043] In another embodiment, a limiting post is formed on the locking piece 42, and an arc-shaped fourth sliding groove is formed in the lock box 1 for the limiting post to slide in. Alternatively, a first limiting part and a second limiting part located on both sides of the limiting post are formed in the lock box 1, which can also achieve the function of controlling the rotation amplitude of the locking piece 42.

[0044] As one implementation, in this embodiment, one side of the square tongue plate 33 is an inclined guide surface 36, such as... Figure 5 As shown, the guide surface 36 is located on the side of the locking groove 34 away from the square tongue 31. When the square tongue 31 extends out of the lock box 1, the guide surface 36 is opposite to the locking post 44. During the subsequent movement of the square tongue plate 33 into the lock box 1, the guide surface 36 abuts against the locking post 44, which can guide the locking piece 42 to rotate counterclockwise, thereby causing the locking post 44 to move into the locking groove 34, thus completing the limiting of the square tongue plate 33.

[0045] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A self-latching lock characterized in that, This includes the lock box and its internal latch assembly, square latch assembly, and trigger assembly; The latch assembly includes a latch, a fixing block, a first spring, and a slider connected to the latch and slidably disposed in the lock box. The fixing block is fixed between the latch and the slider, and the first spring applies an outward force to the latch. The square tongue assembly includes a square tongue, a second spring, and a square tongue plate slidably disposed within the lock box. A locking groove is formed on the side of the square tongue plate, and the second spring applies an outward force to the square tongue plate. The triggering assembly includes a first paddle, a locking plate, and a third spring. The locking plate is rotatably disposed within the lock box. One side of the locking plate has a locking post that can be embedded in the locking groove, and the other side has the first paddle rotatably disposed thereon. The side of the first paddle near the tongue assembly has a paddle part, and the other side is connected to the third spring. The third spring applies a force to the first paddle, causing the side of the paddle part to abut against the fixing block and causing the locking post to be embedded in the locking groove. When the front end of the actuating part is located between the slider and the fixed block, the front end extends to the path on which the slider slides outward.

2. The self-locking mechanism as described in claim 1, characterized in that, The lock box is provided with a second lever that rotates inside. The outer periphery of the second lever extends outward to form a clearance protrusion and a lever head. The distance between one side of the clearance protrusion and the rotation center of the second lever is less than the distance between the other side of the clearance protrusion and the rotation center. The lever head abuts against the outer side of the slider. A relief plate is formed on the other side of the first paddle that abuts against the outer peripheral surface of the second paddle; When the second paddle rotates and retracts the oblique tongue, the yielding plate moves from one side of the yielding protrusion to the other side, the first paddle rotates, and the front end of the paddle moves out of the path on which the slider slides outward.

3. The self-locking mechanism as described in claim 2, characterized in that, The lock box is rotatably provided with a third lever, on which a first sliding groove and a first lever are formed; The second lever is hinged to a second connecting rod, and a second sliding groove is formed on the second connecting rod. The first lever is slidably disposed in the second sliding groove. A second lever is formed on the square tongue plate and is slidably disposed in the first groove.

4. The self-locking mechanism as described in claim 3, characterized in that, A third lever is formed on the third lever; The second spring is a torsion spring, with one end of its torsion arm fixed inside the lock box and the other end abutting against the third lever.

5. The self-locking mechanism as described in claim 2, characterized in that, A limiting post is fixedly installed inside the lock box; The locking piece extends outward from its side to form a first limiting part and a second limiting part respectively disposed on both sides of the limiting post.

6. The self-locking mechanism as described in claim 5, characterized in that, The second lever has an arc-shaped third groove that fits onto the limiting post.

7. The self-locking mechanism as described in claim 5, characterized in that, The third spring is a tension spring, with one end connected to the limiting post and the other end connected to the relief plate.

8. The self-locking mechanism as described in claim 2, characterized in that, Limiting posts are formed on the locking piece; The lock box has an arc-shaped fourth sliding groove for the sliding of the limiting post, or the lock box has a first limiting part and a second limiting part located on both sides of the limiting post.

9. The self-locking mechanism as described in any one of claims 1 to 8, characterized in that, One side of the square tongue plate is an inclined guide surface, which is located on the side of the locking groove away from the square tongue. When the square tongue extends out of the lock box, the guide surface is opposite to the locking post.

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