Protective cover for alarm

Abstract

The utility model relates to a protective cover for an alarm. The protective cover comprises a cover body base, a turning cover, a hinging structure and an unlocking structure, the cover body base comprises an annular base body used for being arranged on the peripheral side of the emergency alarm in a surrounding mode. The flip cover comprises a main cover plate used for covering the emergency alarm. The hinge structure comprises a hinge groove, a hinge seat correspondingly arranged in the hinge groove, a hinge shaft rotationally arranged on the hinge seat in a penetrating mode and an elastic piece arranged on the hinge shaft. The unlocking structure comprises a connecting groove which is formed in the connecting convex block and is clamped and matched with the connecting convex block, and a connecting pin which movably penetrates through the connecting groove and the connecting convex block; a clamping groove is formed in the side face of the connecting protruding block, a spring plunger is arranged on the side wall of the connecting groove, and the spring plunger is elastically clamped in the clamping groove. The button protection cover can solve the problems that a turning cover of a traditional button protection cover is easy to shake, a plug pin is easy to bend, and the protection cover is difficult to open and disassemble.

Description

Technical Field

[0001] This utility model relates to the field of rail transit technology, and in particular to a protective cover for an alarm device on a rail transit vehicle. Background Technology

[0002] With the rapid development of modern rail transit technology, emergency alarms inside rail transit vehicles have become crucial devices for ensuring passenger safety. However, the design of existing emergency alarm button covers has many problems that urgently need to be addressed. These problems not only affect the normal use of the covers but may also threaten passenger safety in emergencies. Currently, emergency alarm button covers mainly use pins and torsion springs to lock the base and flip cover together, and then lock them in place with pins. While this design can prevent accidental activation to some extent, it has revealed many problems in actual use:

[0003] 1. The flip cover is prone to shaking: Due to the large gap between the base and the flip cover, the flip cover is prone to shaking during use. This not only affects the stability of the protective cover, but may also hinder operation in an emergency.

[0004] 2. The pin is prone to bending: During frequent use, the pin is prone to bending, causing it to get stuck and unable to be pulled out. This not only affects the normal use of the protective cover, but may also delay rescue time in an emergency.

[0005] 3. The protective cover is difficult to open: Due to a design flaw, the protective cover is difficult to open in a short time, which may pose a threat to passenger safety in an emergency.

[0006] 4. Difficult to disassemble and assemble: The process of disassembling and assembling the protective cover is relatively complicated, with high damping and poor spring return. This not only increases the difficulty of maintenance, but may also affect the service life of the protective cover. Utility Model Content

[0007] This utility model provides a protective cover for an alarm, which can solve the technical problems of traditional button protective covers, such as easy shaking of the flip cover, easy bending of the pin, difficulty in opening the protective cover, and difficulty in disassembly and assembly.

[0008] To solve the above-mentioned technical problems, this utility model provides a protective cover for an alarm, comprising:

[0009] The cover base includes an annular base body for detachably mounted on the carriage wall of a rail transit vehicle, the annular base body being used to surround the periphery of an emergency alarm.

[0010] The flip cover includes a main cover plate for covering the top of the emergency alarm; when the main cover plate is placed on the annular base body, the bottom surface of the main cover plate abuts against the top surface of the annular base body.

[0011] The hinge structure includes a hinge groove located on one side of the top surface of the annular base body and the bottom surface of the main cover plate, a hinge seat correspondingly located on the other side and situated within the hinge groove, a hinge shaft rotatably passing through the hinge seat, and an elastic element disposed on the hinge shaft. The two ends of the elastic element are respectively connected to the top surface of the annular base body and the bottom surface of the main cover plate. The hinge shaft movably passes through the two side walls of the hinge groove.

[0012] The unlocking structure includes a connecting protrusion located on one side of the top surface of the annular base body and the bottom surface of the main cover plate, a connecting groove correspondingly located on the other side and engaging with the connecting protrusion, and a connecting pin that moves through the connecting groove and the connecting protrusion; the side of the connecting protrusion is provided with a snap-fit ​​groove, and the side wall of the connecting groove is provided with a spring plunger, which is elastically snapped into the snap-fit ​​groove.

[0013] Optionally, the main body of the annular base is configured as a circular ring structure, and the main cover plate is configured as a circular structure;

[0014] The main cover plate includes a circular top cover and an annular cover plate protrusion located on the peripheral edge of the bottom surface of the circular top cover; the hinge groove or the hinge seat is located on one side of the annular cover plate protrusion, and the connecting protrusion or the connecting groove is located on the other side of the annular cover plate protrusion.

[0015] Optionally, the hinge groove and the connecting groove are respectively radially through both sides of the annular cover plate protrusion, and the radial center line of the hinge groove and the radial center line of the connecting groove are both located on the same straight line.

[0016] The hinge seat and the connecting protrusion are respectively radially protruding on both sides of the annular base body, and the radial center line of the hinge seat and the radial center line of the connecting protrusion are both located on the same straight line.

[0017] Optionally, the connecting groove includes a limiting groove on the bottom surface of the annular cover plate protrusion and an outer groove communicating with the outside of the limiting groove. The two sides of the outer groove penetrate the annular cover plate protrusion. One side of the limiting groove communicates with the cover plate cavity surrounded by the annular cover plate protrusion, and the other side is closed.

[0018] When the main cover plate is placed on the annular base body, the top of the connecting protrusion is limited to the limiting groove.

[0019] Optionally, a spring plunger is provided on each of the two opposite sidewalls of the connecting groove, and a circular snap-fit ​​groove is provided on each side of the connecting protrusion, with the positioning ball heads of the two spring plungers elastically snapped into the two circular snap-fit ​​grooves in a one-to-one correspondence.

[0020] Optionally, a notch is provided on each side of the connecting groove protruding from the annular cover plate, and the spring plunger is provided on the sidewall of the adjacent connecting groove and the notch.

[0021] The two groove sidewalls are provided with corresponding first positioning holes, and the connecting protrusion is provided with corresponding second positioning holes. The diameter of the second positioning hole is larger than the diameter of the first positioning hole, and the connecting pin passes through the first positioning hole and the second positioning hole and protrudes out of the notch groove.

[0022] Optionally, the connecting groove is a rectangular groove, and the connecting protrusion is a rectangular block.

[0023] Optionally, the top surface of the annular base body is uniformly provided with multiple connecting holes, and multiple connecting screws are correspondingly provided in the multiple connecting holes for detachable connection to the car wall of the rail transit vehicle.

[0024] Optionally, the elastic element includes a torsion spring passing through the hinge shaft, with one end of the torsion spring connected to the circular top cover and the other end connected to the annular base body.

[0025] Optionally, a third positioning hole is provided through the circular top cover, and a fourth positioning hole is provided through the annular base body;

[0026] One end of the torsion spring passes through the third positioning hole, and the other end passes through the fourth positioning hole.

[0027] The beneficial effects of the technical solution provided by this utility model include:

[0028] By elastically hinged one side of the flip cover to one side of the cover base, and locking the other side of the flip cover to the other side of the cover base via a spring plunger, and then using a connecting pin to lock the flip cover and cover base together from the locking side of the spring plunger, both sides of the flip cover are connected to the cover base. This reduces the gap between the cover base and the flip cover, making the flip cover connection stable, reliable, and less prone to shaking. Furthermore, locking the flip cover and cover base together with the spring plunger, and then using the connecting pin for positioning, reduces the force on the connecting pin, preventing it from bending and becoming stuck during frequent use. Furthermore, the flip cover and the cover base are locked by a connecting pin and a spring plunger, making unlocking convenient. Simply pull out the connecting pin and flip the flip cover to overcome the elastic force of the spring plunger to open it. During the opening process, the elastic element on the hinge side can also assist in opening the flip cover, making it easy and simple to open. Moreover, by detachably mounting the cover base on the wall of the rail transit vehicle, the entire structure can be easily installed and disassembled. In addition, the flip cover and the cover base are movably hinged by a hinge shaft and an elastic element, which makes it relatively easy to disassemble and install the hinge shaft and the elastic element, thus facilitating the disassembly and maintenance of the flip cover. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a three-dimensional structural diagram of the protective cover for the alarm device described in an embodiment of the present invention. Figure 1 ;

[0031] Figure 2 This is a three-dimensional structural diagram of the protective cover for the alarm device described in an embodiment of the present invention. Figure 2 ;

[0032] Figure 3 This is a three-dimensional structural diagram of the base of the protective cover for the alarm as described in an embodiment of the present invention. Figure 1 ;

[0033] Figure 4 This is a three-dimensional structural diagram of the base of the protective cover for the alarm as described in an embodiment of the present invention. Figure 2 ;

[0034] Figure 5 This is a three-dimensional structural diagram of the flip-top protective cover for an alarm device according to an embodiment of the present invention. Figure 1 ;

[0035] Figure 6 This is a three-dimensional structural diagram of the flip-top protective cover for an alarm device according to an embodiment of the present invention. Figure 2 .

[0036] In the diagram: 10. Protective cover for the alarm; 100. Cover base; 110. Annular base body; 112. Connecting screw; 114. Connecting hole; 120. Hinge seat; 130. Hinge shaft; 140. Elastic element; 150. Connecting protrusion; 152. Snap-fit ​​groove; 154. Second positioning hole; 200. Flip cover; 210. Main cover plate; 212. Circular top cover; 214. Annular cover plate protrusion; 220. Hinge groove; 230. Connecting groove; 232. Limiting groove; 234. Outer groove; 236. First positioning hole; 240. Spring plunger; 250. Notch groove. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0038] like Figures 1 to 2 As shown, this utility model proposes a protective cover 10 for an alarm, including a cover base 100 and a flip cover 200, a hinge structure that hinges the cover base 100 and the flip cover 200 from one side, and an unlocking structure that locks the cover base 100 and the flip cover 200 from the other side. The protective cover composed of the cover base 100 and the flip cover 200 can cover and protect the emergency alarm on rail transit vehicles. Furthermore, the hinge structure allows the cover base 100 and the flip cover 200 to be hinged from one side, and the unlocking structure allows them to be locked and unlocked from the other side. When the flip cover 200 is locked to the cover base 100 using the unlocking structure, the emergency alarm is protected; when the emergency alarm needs to be activated, the unlocking structure can be used to release the lock on the flip cover 200 and the cover base 100, allowing the flip cover 200 to be flipped open to expose the emergency alarm.

[0039] Specifically, such as Figures 1 to 4As shown, the cover base 100 may include an annular base body 110 for detachably mounted on the wall of a rail transit vehicle, the annular base body 110 being used to surround the periphery of the emergency alarm. Furthermore, the flip cover 200 may include a main cover plate 210 for covering the emergency alarm, with the bottom surface of the main cover plate 210 abutting against the top surface of the annular base body 110 when the main cover plate 210 is placed on top of the annular base body 110. By abutting the bottom surface of the main cover plate 210 against the top surface of the annular base body 110, the two fit tightly without gaps.

[0040] Furthermore, the hinge structure may include a hinge groove 220 located on one side of the top surface of the annular base body 110 and the bottom surface of the main cover plate 210, a hinge seat 120 located on the other side of the annular base body 110 and in the hinge groove 220, a hinge shaft 130 rotatably passing through the hinge seat 120, and an elastic member 140 provided on the hinge shaft 130. The two ends of the elastic member 140 are respectively connected to the top surface of the annular base body 110 and the bottom surface of the main cover plate 210, and the hinge shaft 130 is movably passing through the two side walls of the hinge groove 220. Furthermore, the unlocking structure may include a connecting protrusion 150 located on the other side of one of the top surface of the annular base body 110 and the bottom surface of the main cover plate 210, a connecting groove 230 correspondingly located on the other side and engaging with the connecting protrusion 150, and a connecting pin that moves through the connecting groove 230 and the connecting protrusion 150; the side of the connecting protrusion 150 is provided with a snap-fit ​​groove 152, and the side wall of the connecting groove 230 is provided with a spring plunger 240, which is elastically snapped into the snap-fit ​​groove 152.

[0041] By elastically hinged one side of the flip cover 200 to one side of the cover base 100, and locking the other side of the flip cover 200 to the other side of the cover base 100 via a spring plunger 240, and then locking the flip cover 200 and the cover base 100 together with a connecting pin from the locking side of the spring plunger 240, both sides of the flip cover 200 are connected to the cover base 100. This reduces the gap between the cover base 100 and the flip cover 200, making the connection of the flip cover 200 stable, reliable, and less prone to shaking. Furthermore, locking the flip cover 200 and the cover base 100 together with the spring plunger 240, and then using the connecting pin for connection and positioning, reduces the force on the connecting pin, preventing it from bending and becoming stuck during frequent use. Furthermore, the flip cover 200 and the cover base 100 are locked by the connecting pin and the spring plunger 240, and unlocking is convenient. Simply pull out the connecting pin and flip the flip cover 200 to overcome the elastic force of the spring plunger 240 to open the flip cover 200. Moreover, the elastic element 140 on the hinge side can also help open the flip cover 200 during the opening process, making the opening of the flip cover 200 convenient and simple. In addition, by detachably installing the cover base 100 on the car wall of the rail transit vehicle, the entire structure can be easily installed and disassembled. Furthermore, the flip cover 200 and the cover base 100 are movably hinged by the hinge shaft 130 and the elastic element 140, and the hinge shaft 130 and the elastic element 140 can be easily disassembled and assembled, thereby facilitating the disassembly and maintenance of the flip cover 200.

[0042] In addition, such as Figures 3 to 4 As shown, the top surface of the annular base body 110 of the cover base 100 is evenly provided with a plurality of connecting holes 114, and a plurality of connecting screws 112 are correspondingly provided in the plurality of connecting holes 114 for detachable connection to the car wall of the rail transit vehicle. By providing a plurality of connecting holes 114 through the thickness direction of the annular base body 110, the annular base body 110 can be detachably connected to the car wall of the rail transit vehicle by means of connecting screws 112, which facilitates the installation and removal of the annular base body 110 and the protective cover 10 for the alarm. Moreover, all of the plurality of connecting holes 114 can be threaded holes. Furthermore, the top and bottom surfaces of the annular base body 110 are both flat, which allows the bottom surface of the annular base body 110 to better fit against the flat car wall of the rail transit vehicle.

[0043] Furthermore, the annular base body 110 of the cover base 100 can be designed as a circular structure, and the main cover plate 210 of the flip cover 200 can be designed as a circular structure. This not only allows the flip cover 200 to better fit with the cover base 100, but also allows the annular base body 110 to better surround the emergency alarm on the car wall of the rail transit vehicle. Its outer side has no sharp edges and is not likely to cause accidental bumps or injuries to external objects or people.

[0044] In addition, such as Figures 1 to 2 ,as well as Figures 5 to 6 As shown, the main cover plate 210 of the flip cover 200 may include a circular top cover 212 and an annular cover plate protrusion 214 located on the peripheral edge of the bottom surface of the circular top cover 212. A closing cavity can be formed by the circular top cover 212 and the annular cover plate protrusion 214 to accommodate and seal the emergency alarm on the carriage wall from the top. Furthermore, a hinge slot 220 or hinge seat 120 may be provided on one side of the annular cover plate protrusion 214, and a connecting protrusion 150 or connecting groove 230 may be provided on the other side of the annular cover plate protrusion 214, thereby enabling hinged connection between the cover base 100 and the flip cover 200 from one side, and locking or unlocking of the cover base 100 and the flip cover 200 from the other side.

[0045] In some embodiments, the hinge groove 220 and the connecting groove 230 can be radially disposed on both sides of the annular cover plate protrusion 214, and the radial center lines of the hinge groove 220 and the connecting groove 230 are both located on the same straight line. This allows both the hinge groove 220 and the connecting groove 230 to be disposed on the bottom surface of the annular cover plate protrusion 214 of the flip cover 200, and both to penetrate the annular cover plate protrusion 214, facilitating manufacturing. Furthermore, by aligning the radial center lines of the hinge groove 220 and the connecting groove 230 on the same straight line, not only is it easier to manufacture the hinge groove 220 and the connecting groove 230, but it also ensures that the hinge position and the locking / unlocking position of the flip cover 200 are on the same straight line, resulting in balanced, stable, and reliable force distribution during unlocking and locking.

[0046] Furthermore, the connecting groove 230 may include a limiting groove 232 on the bottom surface of the annular cover plate protrusion 214, and an outer groove 234 communicating with the outer side of the limiting groove 232. The outer groove 234 extends through the annular cover plate protrusion 214 on both sides. One side of the limiting groove 232 communicates with the cover plate cavity enclosed by the annular cover plate protrusion 214, while the other side is closed. When the main cover plate 210 is placed on the annular base body 110, the top of the connecting protrusion 150 is limited in the limiting groove 232. The limiting groove 232 on the inner side of the connecting groove 230 may correspond to the top of the connecting protrusion 150, and can cover and limit it from all sides of the top of the connecting protrusion 150. Moreover, the outer groove 234 on the outer side of the connecting groove 230 can also limit the connecting protrusion from both sides, and the flip cover 200 can be flipped from the outer opening of the outer groove 234.

[0047] Furthermore, a spring plunger 240 is provided on each of the two opposite sidewalls of the connecting groove 230, and a circular locking groove 152 is provided on each side of the connecting protrusion 150. The positioning ball heads of the two spring plungers 240 are elastically engaged in the two circular locking grooves 152. By providing a spring plunger 240 on each side of the limiting groove 232, the connecting groove 230 and the connecting protrusion 150 can be elastically locked or unlocked from both sides, which is stable and reliable. When locked, the positioning ball head at the end of the spring plunger 240 on the sidewall of the connecting groove 230 elastically abuts against the circular locking groove 152 on the side of the connecting protrusion 150; when the flip cover 200 is flipped by external force, the external force overcomes the elastic force of the spring plunger 240 on the connecting protrusion 150, causing the spring plunger 240 to separate from the connecting protrusion 150.

[0048] Furthermore, each side of the connecting groove 230 of the annular cover protrusion 214 is provided with a notch 250, and the spring plunger 240 is provided on the side wall of the adjacent connecting groove 230 and notch 250. By providing two notches 250 on each side of the connecting groove 230, it is not only convenient to set the spring plunger 240 on the side of the connecting groove 230, but also convenient to set the connecting pin on both sides of the connecting groove 230 to lock or unlock the connecting protrusion 150, and also convenient to flip the cover 200 from the notches 250 on both sides.

[0049] Furthermore, corresponding first positioning holes 236 can be provided on the two groove sidewalls, and corresponding second positioning holes 154 can be provided on the connecting protrusion 150. The diameter of the second positioning hole 154 is larger than the diameter of the first positioning hole 236, and the connecting pin passes through the first positioning hole 236 and the second positioning hole 154 and protrudes into the notch groove 250. By passing the connecting pin through the first positioning holes 236 on both sides of the groove sidewall of the connecting groove 230 and through the second positioning hole 154 on the connecting protrusion 150, the connecting groove 230 and the connecting protrusion 150 can be locked. Moreover, by making the diameter of the second positioning hole 154 larger than the diameter of the first positioning hole 236, the force exerted on the connecting pin by the connecting protrusion 150 during locking can be reduced, preventing the connecting pin from deforming and becoming impossible to disassemble.

[0050] Furthermore, the connecting groove 230 can be designed as a rectangular groove, and the connecting protrusion 150 can be designed as a corresponding rectangular block. The structure is simple, easy to manufacture, and also easy to lock and unlock.

[0051] In addition, such as Figures 1 to 4As shown, the hinge seat 120 and the connecting protrusion 150 can respectively protrude radially from both sides of the annular base body 110, and the radial center lines of the hinge seat 120 and the connecting protrusion 150 are both on the same straight line. In this way, the hinge seat 120 and the hinge groove 220 are perfectly matched and correspond, and the connecting protrusion 150 and the connecting groove 230 are perfectly matched and correspond. Moreover, the hinge seat 120 can be designed as a U-shaped block structure, which facilitates the hinge shaft 130 to be rotatably mounted on the two protruding ends of the U-shaped block structure, and also facilitates the elastic element 140 to be limited and positioned in the middle groove of the U-shaped block structure.

[0052] Furthermore, the elastic element 140 may include a torsion spring passing through the hinge shaft 130, with one end of the torsion spring connected to the circular top cover 212 and the other end connected to the annular base body 110. The torsion spring provides an elastic connection and limitation between the flip cover 200 and the cover base 100, facilitating the opening of the flip cover 200. The main body of the torsion spring may be located in the central groove of the U-shaped block structure and pass through the hinge shaft 130. Moreover, a third positioning hole may be provided through the circular top cover 212, and a fourth positioning hole may be provided through the annular base body 110; one end of the torsion spring can be movably inserted into the third positioning hole, and the other end can be movably inserted into the fourth positioning hole. In this way, the torsion spring can be stably installed between the circular top cover 212 of the flip cover 200 and the annular base body 110 of the cover base 100, preventing it from easily falling off.

[0053] The working process of the protective cover 10 for the alarm proposed in this utility model is as follows:

[0054] In its initial state (when no alarm is triggered), the flip cover 200 is closed on the cover base 100 and securely locked by the spring plunger 240. The spring plunger 240 is installed on the side wall of the connecting groove 230 inside the flip cover 200. Its own elasticity presses the flip cover 200 firmly against the cover base 100, thus effectively locking the flip cover 200. Simultaneously, a connecting pin passes through the connecting groove 230 of the flip cover 200 and the connecting protrusion 150 of the cover base 100. In this way, the flip cover 200 is firmly locked in the closed position, and the emergency alarm is fully protected within the flip cover 200 and the cover base 100, free from external interference.

[0055] When an alarm (emergency) needs to be triggered, an external force must first be applied to the flip cover 200. This force can be a pulling or pushing force in a specific direction. This force must be sufficient to overcome the torque generated by the torsion spring and the pressure applied by the spring plunger 240 so that the flip cover 200 will begin to move. As the flip cover 200 continues to move, when it reaches a certain point, the spring plunger 240 will be guided by the guide groove provided on the side wall of the connecting groove 230 and smoothly disengage from the locking hole (i.e., the snap-fit ​​groove 152). At this time, the flip cover 200 will begin to rotate around the connecting shaft under the drive of the remaining torque of the torsion spring, thereby opening the flip cover 200 and exposing the emergency alarm for alarm operation.

[0056] When it is necessary to restore the normal state (after an alarm), the flip cover 200 can be rotated back to the closed position. During rotation, the spring plunger 240 moves along the guide groove on the side wall of the connecting groove 230 until it reaches the position corresponding to the locking hole (i.e., the snap-fit ​​groove 152) on the connecting protrusion 150. When the flip cover 200 is fully closed, the connecting pin can be precisely inserted into the positioning hole of the connecting groove 230 and the connecting protrusion 150, thereby locking the flip cover 200 back to the closed state. At this point, the protective cover reset operation is completed.

[0057] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0058] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the present invention.

Claims

1. A protective cover (10) for an alarm, characterized in that include: The cover base (100) includes an annular base body (110) for detachably mounted on the wall of a rail transit vehicle, the annular base body (110) being used to surround the periphery of the emergency alarm. The flip cover (200) includes a main cover plate (210) for covering the top of the emergency alarm; when the main cover plate (210) is placed on the annular base body (110), the bottom surface of the main cover plate (210) abuts against the top surface of the annular base body (110); The hinge structure includes a hinge groove (220) located on one side of the top surface of the annular base body (110) and the bottom surface of the main cover plate (210); a hinge seat (120) correspondingly located on the other side and situated within the hinge groove (220); a hinge shaft (130) rotatably passing through the hinge seat (120); and an elastic element (140) located on the hinge shaft (130). The two ends of the elastic element (140) are respectively connected to the top surface of the annular base body (110) and the bottom surface of the main cover plate (210). The hinge shaft (130) movably passes through the two side walls of the hinge groove (220). The unlocking structure includes a connecting protrusion (150) located on the other side of one of the top surface of the annular base body (110) and the bottom surface of the main cover plate (210), a connecting groove (230) correspondingly located on the other side and engaging with the connecting protrusion (150), and a connecting pin that moves through the connecting groove (230) and the connecting protrusion (150); the side of the connecting protrusion (150) is provided with a snap-fit ​​groove (152), and the side wall of the connecting groove (230) is provided with a spring plunger (240), which is elastically snapped into the snap-fit ​​groove (152).

2. A protective cover (10) for an alarm according to claim 1, characterized in that The annular base body (110) is designed as a circular structure, and the main cover plate (210) is designed as a circular structure; The main cover plate (210) includes a circular top cover (212) and an annular cover plate protrusion (214) located on the peripheral edge of the bottom surface of the circular top cover (212); the hinge groove (220) or the hinge seat (120) is located on one side of the annular cover plate protrusion (214), and the connecting protrusion (150) or the connecting groove (230) is located on the other side of the annular cover plate protrusion (214).

3. A protective cover (10) for an alarm according to claim 2, characterized in that The hinge groove (220) and the connecting groove (230) are respectively radially provided on both sides of the annular cover plate protrusion (214), and the radial center line of the hinge groove (220) and the radial center line of the connecting groove (230) are both located on the same straight line. The hinge seat (120) and the connecting protrusion (150) are respectively radially protruding on both sides of the annular base body (110), and the radial center line of the hinge seat (120) and the radial center line of the connecting protrusion (150) are both located on the same straight line.

4. The protective cover (10) for an alarm according to claim 3, characterized in that The connecting groove (230) comprises a limiting groove (232) arranged on the bottom surface of the annular cover plate protrusion (214), and an outer groove (234) communicated with the outer side of the limiting groove (232), the two sides of the outer groove (234) penetrating the annular cover plate protrusion (214), one side of the limiting groove (232) being communicated with the cover plate cavity surrounded by the annular cover plate protrusion (214) and the other side being closed. When the main cover plate (210) is arranged on the annular base body (110), the top of the connecting protrusion (150) is limited in the limiting groove (232).

5. The protective cover (10) for an alarm according to claim 3, characterized in that, The opposite two groove side walls of the connecting groove (230) are respectively provided with one spring plunger (240), and the two sides of the connecting protrusion (150) are respectively provided with one circular clamping groove (152) correspondingly, and the positioning balls of the two spring plungers (240) are elastically clamped in the two circular clamping grooves (152) correspondingly.

6. A protective cover (10) for an alarm according to claim 5, characterized in that The two sides of the connecting groove (230) of the annular cover plate protrusion (214) are respectively provided with one notch groove (250), and the spring plunger (240) is arranged on the groove side wall of the adjacent connecting groove (230) and notch groove (250); The two groove side walls are provided with corresponding first positioning holes (236), and the connecting protrusion (150) is provided with corresponding second positioning holes (154), the hole diameter of the second positioning hole (154) is larger than the hole diameter of the first positioning hole (236), and the connecting pin penetrates the first positioning hole (236) and the second positioning hole (154) and protrudes in the notch groove (250).

7. The protective cover (10) for an alarm according to claim 3, characterized in that, The connecting groove (230) is arranged as a rectangular groove, and the connecting protrusion (150) is arranged as a rectangular block.

8. A protective cover (10) for an alarm according to claim 3, characterized in that The top surface of the annular base body (110) is uniformly provided with a plurality of connecting holes (114), and a plurality of connecting screws (112) are correspondingly arranged in the plurality of connecting holes (114) for detachably connecting the car wall of the rail transit vehicle.

9. The protective cover (10) for an alarm according to claim 3, characterized in that, The elastic member (140) comprises a torsion spring penetrating the hinge shaft (130), one end of the torsion spring being connected to the circular top cover (212) and the other end being connected to the annular base body (110).

10. A protective cover (10) for an alarm according to claim 9, characterized in that The circular top cover (212) is provided with a third positioning hole penetrating the annular base body (110), and the annular base body (110) is provided with a fourth positioning hole penetrating the annular base body (110). One end of the torsion spring penetrates the third positioning hole, and the other end penetrates the fourth positioning hole.

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