Expandable central locking device of explosion-proof shell of multi-cavity lifting door

Abstract

The invention relates to the field of mining explosion-proof shells, in particular to an expandable central locking device of a multi-cavity lifting door explosion-proof shell, and aims to solve the problems that an existing locking mechanism is poor in expansibility, complex in structure, invisible in built-in and prone to clamping stagnation. The key points of the technical scheme are as follows: all stop button rods corresponding to the quick-opening doors are linked through an external modular mechanism which drives a locking plate chain by a linkage rod; at the locking position, the linkage rod locks the disconnecting switch handle and drives the locking plate chain to prevent the quick-opening door from being opened; and at the unlocking position, locking is released, door opening is allowed, and any door opening action can back lock the locking plate chain through the stop button rod, so that the power-off state is forcibly maintained. The interlocking device is mainly used for ensuring that all the quick-opening doors on the multi-cavity explosion-proof shell and the power isolation switch are reliably interlocked.

Description

Technical Field

[0001] This invention relates to the technical field of explosion-proof enclosures for mining applications, and in particular to a central locking device for an expandable multi-cavity lifting door explosion-proof enclosure. Background Technology

[0002] For equipment operating in the explosive environment of coal mines, interlocking devices must be installed between all quick-opening doors and power disconnect switches to ensure the safety of operators and meet the relevant safety regulations.

[0003] Currently, the number of combined power supply equipment in mines is increasing, and the number of quick-opening doors is no longer limited to one or two or three. According to safety standards, each quick-opening door of a mine explosion-proof enclosure must have a reliable interlocking function with the power supply isolating switch.

[0004] As the integration of downhole equipment continues to increase, explosion-proof enclosures need to be equipped with multiple quick-opening doors (such as power supply chambers, control chambers, wiring chambers, etc.). However, existing mechanical interlocking mechanisms are mostly designed for single or double doors, making it difficult to expand to three-door or higher structures. For example, traditional linkage mechanisms can typically only interlock two doors. When the number of doors increases or the layout changes, the entire interlocking system often needs to be redesigned, resulting in poor versatility and high maintenance costs. Furthermore, multi-stage gear, rack, or cam transmission mechanisms used to achieve multi-door interlocking are prone to jamming due to wear or deformation after long-term operation, affecting the reliability of unlocking and locking.

[0005] In general, existing interlocking structures are suitable for explosion-proof enclosures with a single door or a small number of quick-opening doors. For explosion-proof enclosures with multiple quick-opening doors, current technology struggles to ensure that each door effectively interlocks with the isolating switch. Currently, interlocking structures that support flexible expansion of the number of quick-opening doors often suffer from structural complexity and manufacturing difficulties. Furthermore, many built-in interlocking structures are prone to jamming or damage because their movement is not visible, and these faults are difficult to detect in a timely manner, ultimately preventing the quick-opening doors from opening properly.

[0006] Therefore, it is necessary to provide a new expandable central locking device for the explosion-proof housing of a lifting door to solve the above-mentioned technical problems. Summary of the Invention

[0007] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0008] To address this, the present invention proposes a central locking device for an expandable multi-cavity lifting door explosion-proof shell, which can effectively solve the problems of poor expandability, complex structure, difficult maintenance, and easy jamming and damage due to being built-in and invisible in the prior art.

[0009] A central locking device for an expandable multi-cavity lifting door explosion-proof shell according to an embodiment of the present invention includes: A central locking mechanism includes a laterally movable linkage and a locking plate chain consisting of multiple locking plates hinged sequentially via locking links, wherein the first locking plate is fixedly connected to the linkage. A disconnector operating mechanism, comprising a lockable disconnector handle; At least two quick-opening door modules, each quick-opening door module including a lifting quick-opening door and a stop button lever linked to the quick-opening door; wherein, each of the locking plates is in transmission engagement with the stop button lever of the corresponding quick-opening door module; The linkage has a locked position and an unlocked position; When the linkage rod is in the locked position, it locks the disconnect switch handle, preventing the disconnect switch from closing, and at the same time drives the locking plate chain to lock each locking plate in the pressed state of the corresponding stop button rod, thereby preventing all quick-opening doors from opening. When the linkage rod is in the unlocked position, it releases the lock on the isolating switch handle and drives the locking plate chain to release the corresponding stop button rod of each locking plate, allowing each quick-opening door to be opened; and when any quick-opening door is opened, its corresponding stop button rod pops out and locks the locking plate that cooperates with it, thereby locking the entire locking plate chain and linkage rod in the unlocked position.

[0010] According to one embodiment of the present invention, the disconnecting switch operating mechanism further includes a stop button and a limiting disc fixed to the disconnecting switch shaft, wherein a limiting notch is provided on the limiting disc; pressing the stop button can cause the circuit breaker to open and cause the limiting notch of the limiting disc to rotate to the unlocking position, at which time the disconnecting switch shaft can be rotated to realize the opening or closing operation.

[0011] According to one embodiment of the present invention, the disconnect switch handle is provided with a handle notch. When the linkage rod is in the locked position, a locking pin fixed on the linkage rod is inserted into the handle notch to prevent the disconnect switch from closing.

[0012] According to one embodiment of the present invention, a return spring is provided at the tail of the stop button lever; a stop button top plate is provided on the inner side of the quick-opening door; when the corresponding quick-opening door is closed, the stop button top plate presses down the stop button lever; when the quick-opening door is opened, the stop button lever pops out under the action of the return spring.

[0013] According to one embodiment of the present invention, the stop button lever is provided with a lever pin; when any of the stop button levers is popped out, its lever pin will be inserted into the locking hole of the locking plate corresponding to the stop button lever, thereby locking the locking plate chain and the linkage rod in the unlocked position.

[0014] According to one embodiment of the present invention, when the door is closed, the limit switch is triggered to generate an electrical signal indicating that the door is closed; when the stop button lever is popped out, the limit switch is opened to generate an electrical signal indicating that the door is open.

[0015] According to one embodiment of the present invention, when adding a quick-opening door module, a locking plate corresponding to the new module is added, and the new locking plate is hinged to the original locking plate chain using a locking linkage. At the same time, the new stop button rod is driven to cooperate with the new locking plate, thereby realizing functional expansion.

[0016] According to one embodiment of the present invention, the entire central locking device is disposed outside the explosion-proof enclosure, and its linkage rod, locking plate, locking link, stop button rod and each connection point are all exposed or visible structures, which facilitates direct observation of its operating status.

[0017] The beneficial effects of this invention are: I. Modular Design, Flexible Expansion: This invention adopts a standardized series structure of locking plates and connecting rods to form a modular central locking mechanism. This design can flexibly adapt to three or more quick-opening doors. When it is necessary to add or remove doors, there is no need to redesign the entire system; only the corresponding modules need to be added or removed. This significantly improves the product's versatility and reduces design, production, and maintenance costs.

[0018] II. External Visual Accessibility and Convenient Operation and Maintenance: The central locking structure of this invention is an external locking type, with all key linkage components located outside the explosion-proof enclosure. This simplifies installation and operation, allowing users to directly observe the real-time movement status of key components such as the locking rod and locking plate, enabling timely detection of any abnormalities or jamming. The external structure also greatly facilitates debugging, inspection, and maintenance.

[0019] III. Simplified Structure and High Reliability: Compared to the complex mechanisms of traditional multi-stage gear and cam transmissions, this invention uses direct linkage between connecting rods and plate chains, resulting in fewer transmission links and a simpler structure. This not only reduces processing difficulty and cost but also fundamentally reduces the risk of jamming due to wear and deformation during long-term operation. It also makes the locking mechanism itself less prone to jamming, thereby greatly improving the long-term reliability of locking and unlocking actions.

[0020] IV. Comprehensive Interlocking, Fully Guaranteed Safety: This invention strictly ensures a mandatory mechanical interlock between the disconnecting switch and the drive unit, as well as between the disconnecting switch and the quick-opening doors of each chamber, thoroughly implementing the ironclad safety rule that power can only be supplied when the power is off and the door is closed. Simultaneously, the device incorporates both mechanical and electrical interlocking: when the quick-closing door is closed, the top plate of the quick-opening door stop button presses against the stop button lever. Behind the stop button lever is a limit switch, which provides an electrical signal, thus forming a dual safety guarantee of mechanical and electrical interlocking, greatly enhancing overall safety.

[0021] V. Strong applicability and clear fulfillment of specific needs: This invention is particularly applicable to explosion-proof cavity structures with lifting-type multi-quick-opening doors, and can meet the complex safety requirements of interlocking between the isolating switch and the drive unit module, and between the isolating switch and each cavity quick-opening door. It provides a reliable and efficient safety interlocking solution for modern and integrated mining combined equipment.

[0022] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a diagram showing the usage state of the present invention; Figure 2 yes Figure 1 A partial structural diagram; Figure 3 This is a schematic diagram of the structure of the present invention; Figure 4 This is a schematic diagram of the operating mechanism of the disconnect switch.

[0026] The labels in the diagram are as follows: 1. Linkage rod; 1-1. Locking pin; 2. Locking plate; 2-1. Locking hole; 3. Locking linkage rod; 4. Isolating switch handle; 4-1. Handle notch; 5. Quick-opening door; 5-1. Stop button top plate; 6. Stop button rod; 6-1. Rod pin; 7. Stop button; 8. Limit plate; 8-1. Limit notch. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be understood that the terms "one side", "the other side", "both sides", "between", "middle", "upper end", "lower end", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention 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 invention.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] The following describes in detail, with reference to the accompanying drawings, a central locking device for an expandable multi-cavity lifting door explosion-proof shell according to an embodiment of the present invention.

[0031] See Figure 1 This embodiment provides a central locking device for an expandable multi-cavity lifting door explosion-proof enclosure. The entire device is located outside the explosion-proof enclosure and uses an external locking mechanism. All linkage components are exposed, and their operating status is clearly visible, allowing users to directly observe them. This effectively avoids jamming malfunctions that may occur due to the lack of visibility of the internal structure, and also simplifies installation, debugging, and maintenance. The device adopts a modular, expandable, and universal interlocking mechanism design, aiming to improve locking performance, reliability, and versatility by reducing the number of transmission links and parts.

[0032] See Figures 1 to 4This embodiment uses an explosion-proof enclosure containing eight quick-opening doors 5 as an example for illustration. These eight quick-opening doors 5 are arranged in a matrix (e.g., 2 rows × 4 columns). The design of this central locking device strictly follows the operational constraints between the drive module, the isolating switch, and the quick-opening doors. Its core innovation lies in its efficient and compact linkage topology, which mainly includes three parts: the central locking mechanism, the isolating switch operating mechanism, and the quick-opening door module group.

[0033] The central locking mechanism is the control core of the entire device; it consists of a transverse locking mechanism (such as...). Figure 1 The interlocking mechanism consists of a linkage rod 1 that moves in the left-right direction and a locking plate chain. This locking plate chain is formed by four independent locking plates 2 connected in series via three locking links 3. The first locking plate 2, located on the far right (closest to the isolating switch), is fixedly connected to the left end of the linkage rod 1, forming a rigid unit. Therefore, moving the linkage rod 1 left or right synchronously drives the entire locking plate chain to move laterally. This modular design allows the interlocking mechanism to be flexibly expanded to accommodate more quick-opening doors according to actual needs.

[0034] The operating mechanism of the disconnecting switch mainly includes a disconnecting switch handle 4, a stop button 7, and a limit switch plate 8. The limit switch plate 8 is fixed on the rotating shaft of the disconnecting switch and has a limit notch 8-1. The disconnecting switch handle 4 has a limit port (i.e., handle notch 4-1). A locking pin 1-1 is fixed to the right end of the linkage rod 1. The stop button 7 is located on the upper part of the handle. When the stop button is pressed, the circuit breaker trips. The button is self-resetting. When the button is pressed, the notch (8-1) of the limit switch plate 8 disengages from the blocking position, allowing the disconnecting switch shaft to rotate.

[0035] Quick-opening door module group: In this embodiment, the eight quick-opening doors 5 are divided into four groups, with two quick-opening doors 5 in each group spatially (e.g., vertically adjacent) connected to the same locking plate 2. Each group includes two lifting quick-opening doors 5 and two stop button levers 6. A stop button top plate 5-1 is fixed to the inside of each quick-opening door 5. Each stop button lever 6 is vertically installed, with a return spring (not labeled in the figure) at its tail and a lever pin 6-1 at its top. The two stop button levers 6 in the same group are driven and engaged with the same locking plate 2. That is, one locking plate 2 is responsible for monitoring and locking the status of the two quick-opening doors 5 associated with it. For multi-cavity quick-opening door explosion-proof shells, only one set of locking plate, connecting rod, and stop button lever mechanism needs to be added, which demonstrates excellent scalability.

[0036] The disconnector switch operating mechanism features an internal interlock: the limit switch plate 8 rotates synchronously with the disconnector switch shaft. When the stop button 7 is not pressed, the disconnector switch is in a fixed closed or open position. The solid portion of the limit switch plate 8 blocks the external mechanism, preventing its shaft from rotating freely. When it is necessary to operate the disconnector switch, the stop button 7 must be pressed first. This action, on the one hand, opens the circuit breaker, and on the other hand, rotates the limit switch plate 8 through the internal linkage mechanism until its limit notch 8-1 aligns with the external stop. Only then can the disconnector switch shaft and the disconnector switch handle 4 be rotated; this is the first safety procedure.

[0037] Interlocking between the central locking mechanism and the disconnecting switch: Linkage rod 1 can switch between the "locked position" and the "unlocked position". The locking mechanism is interlocked with each quick-opening door. When the locking mechanism is in the unlocked position, the quick-opening door can be opened; when it is in the locked position, the quick-opening door cannot be opened. When linkage rod 1 is in the locked position, its right-end locking pin 1-1 is inserted into the handle notch 4-1 of the disconnecting switch handle 4. At this time, the disconnecting switch is locked, the locking pin is inserted into the disconnecting handle, and the disconnecting switch cannot be closed. When linkage rod 1 is pulled to the unlocked position, the locking pin 1-1 is disengaged, releasing the lock on the disconnecting switch handle 4. At this time, linkage rod 1 of the locking mechanism (or its connected components) will be inserted into the handle notch 4-1, the disconnecting switch handle cannot be turned, and the disconnecting switch cannot be operated. Only if the stop button 7 has been pressed at this time can the disconnecting switch be opened (but it still cannot be closed). This ensures that safety requirements are met under any operating conditions and prevents misoperation.

[0038] Interlocking between the central locking mechanism and the quick-opening doors (based on group control): The movement of the linkage 1 synchronously controls the locking state of all quick-opening doors 5 through the locking plate chain, realizing synchronous locking and unlocking among multiple quick-opening doors. The key is that each locking plate 2 controls a group (two) of doors. Door locking in the locked position: When the linkage 1 is in the locked position, the entire locking plate chain is in the corresponding position. At this time, a specific structure on each locking plate 2 simultaneously covers or blocks the ejection path of the two associated stop button levers 6. As long as any quick-opening door 5 in the group is closed (its stop button lever 6 is pressed), the locking plate 2 prevents it from popping up; if both doors in the group are closed, the locking plate 2 simultaneously locks both stop button levers 6. This ensures that in the locked position, all quick-opening doors 5 cannot be opened. Door release in the unlocked position: When the linkage 1 is pulled to the unlocked position, the locking plate chain moves synchronously, and each locking plate 2 moves away, releasing the obstruction of the two associated stop button levers 6. At this time, each quick-opening door 5 is in an independently openable state.

[0039] Feedback and deadbolt mechanism of the quick-opening door state to the central locking mechanism (group deadbolt logic): This is the core logic to ensure safety. Closing process: When a quick-opening door 5 is closed, the stop button top plate 5-1 on its inner side presses down the corresponding stop button lever 6, and the lever pin 6-1 at the top of the stop button lever 6 exits from the locking hole 2-1 of the locking plate 2. Opening and deadbolt process: When any quick-opening door is opened, the quick-opening door stop button lever automatically pops out under the action of the spring force, and the pin of the stop button lever inserts into the hole of the interlocking plate (i.e., the locking plate). At this time, the interlocking plate (i.e., the locking plate) cannot move left or right. Specifically, when any quick-opening door 5 is lifted, its corresponding stop button lever 6 pops out under the action of the spring, and its lever pin 6-1 immediately inserts into the locking hole 2-1 of the associated locking plate 2. Key locking function: Since each locking plate 2 is associated with two quick-opening doors 5, if one of the two quick-opening doors 5 associated with that locking plate 2 is opened, that locking plate 2 will be locked by its corresponding stop button lever 6. Furthermore, because all locking plates 2 are connected in series via locking linkage 3, if one locking plate 2 is locked, the entire locking plate chain cannot move, thus forcibly locking the linkage rod 1, which is fixed to the chain head, in the "unlocked position." This design ensures that if any of the eight quick-opening doors 5 is in the open state, the linkage rod 1 cannot return to the locked position, and the isolating switch handle 4 cannot be locked by the locking pin 1-1, thereby fundamentally eliminating the possibility of opening the door while it is energized, and ensuring a reliable interlock between each door and the isolating switch.

[0040] Electrical interlocking integration: Limit switches can be installed behind the stop button levers to provide electrical interlocking signals for the opening and closing of quick-opening doors. A limit switch (not shown in the figure) can be installed at the end of each stop button lever 6. When the stop button lever 6 is pressed down (door closed), the limit switch is triggered; when the stop button lever 6 is released (door open), the switch resets. The closing signals of these eight quick-opening doors 5 can be connected to the equipment control system to implement the logic and judgment for all door closing, forming a dual mechanical and electrical interlock, effectively improving safety and operational reliability.

[0041] The modular concept of this invention is reflected not only in the increased number of quick-opening doors 5, but also in the flexibility of the grouping method. The aforementioned locking plate 2 corresponding to two quick-opening doors 5 is a preferred compact embodiment. In actual expansion, depending on the shell layout: door groups can be added by adding locking plates 2 and locking linkages 3 to extend the locking plate chain. Grouping can be adjusted: each newly added locking plate 2 can be associated with one, two, or more (depending on mechanical design feasibility) stop button levers 6, thereby adapting to different door layout matrices. This flexibility demonstrates the strong scalability and versatility of this invention. Simultaneously, the interlocking mechanism must adapt to the equipment's working environment, possess sufficient mechanical strength and service life, and have a simple structure for easy installation, debugging, and maintenance.

[0042] Working principle: Power supply procedure: Ensure all quick-opening doors 5 are closed (all stop button levers 6 are pressed down), push the linkage lever 1 to the "locked position", and operate the stop button 7 and the isolating switch handle 4 to supply power.

[0043] Power outage maintenance procedure: Press the stop button 7 to trip the circuit breaker, pull the linkage rod 1 to the "unlocked position" to open any quick-opening door 5 that needs maintenance. Opening any door will trigger a mechanical deadbolt to prevent accidental power restoration.

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A central locking device for an expandable multi-cavity lifting door explosion-proof shell, characterized in that, include: A central locking mechanism includes a laterally movable linkage rod (1) and a locking plate chain consisting of multiple locking plates (2) sequentially hinged together by locking linkage rods (3), wherein the first locking plate (2) is fixedly connected to the linkage rod (1). A disconnector operating mechanism, comprising a lockable disconnector handle (4); At least two quick-opening door modules, each quick-opening door module includes a lifting quick-opening door (5) and a stop button lever (6) linked with the quick-opening door (5); wherein, each of the locking plates (2) is in transmission cooperation with the stop button lever (6) of the corresponding quick-opening door module; The linkage (1) has a locked position and an unlocked position; When the linkage rod (1) is in the locked position, it locks the isolating switch handle (4) to prevent the isolating switch from closing, and at the same time drives the locking plate chain to lock each locking plate (2) to the pressed state of the corresponding stop button rod (6), thereby preventing all quick-opening doors (5) from opening. When the linkage rod (1) is in the unlocked position, it releases the lock on the isolating switch handle (4) and drives the locking plate chain to release the corresponding stop button rod (6) of each locking plate (2), allowing each quick-opening door (5) to be opened; and when any quick-opening door (5) is opened, its corresponding stop button rod (6) pops out and locks the locking plate (2) that it cooperates with, thereby locking the entire locking plate chain and linkage rod (1) in the unlocked position.

2. The central locking device for an expandable multi-cavity lifting door explosion-proof shell as described in claim 1, characterized in that, The disconnector operating mechanism also includes a stop button (7) and a limit plate (8) fixed to the disconnector shaft. The limit plate (8) has a limit notch (8-1). Pressing the stop button (7) will cause the circuit breaker to open and the limit notch (8-1) of the limit plate (8) to rotate to the unlocking position. At this time, the disconnector shaft can be rotated to realize the opening or closing operation.

3. The central locking device for an expandable multi-cavity lifting door explosion-proof shell as described in claim 2, characterized in that, The disconnect switch handle (4) is provided with a handle notch (4-1). When the linkage rod (1) is in the locked position, a locking pin (1-1) fixed on the linkage rod (1) is inserted into the handle notch (4-1) to prevent the disconnect switch from closing.

4. The central locking device for an expandable multi-cavity lifting door explosion-proof shell as described in claim 1, characterized in that, The tail of the stop button lever (6) is provided with a return spring; the inner side of the quick-opening door (5) is provided with a stop button top plate (5-1); when the corresponding quick-opening door (5) is closed, the stop button top plate (5-1) presses down the stop button lever (6); when the quick-opening door (5) is opened, the stop button lever (6) pops out under the action of the return spring.

5. The central locking device for an expandable multi-cavity lifting door explosion-proof shell as described in claim 4, characterized in that, The stop button lever (6) is provided with a lever pin (6-1); when any of the stop button levers (6) pops out, its lever pin (6-1) will be inserted into the locking hole (2-1) of the locking plate (2) corresponding to the stop button lever (6), thereby locking the locking plate chain and linkage rod (1) in the unlocked position.

6. The central locking device for an expandable multi-cavity lifting door explosion-proof shell as described in claim 4 or 5, characterized in that, A limit switch is also provided at the end of the stop button lever (6); when the stop button lever (6) is pressed down, the limit switch is triggered to generate an electrical signal indicating that the door is closed; when the stop button lever (6) is popped out, the limit switch is opened to generate an electrical signal indicating that the door is open.

7. The central locking device for an expandable multi-cavity lifting door explosion-proof shell as described in claim 1, characterized in that, When adding a quick-opening door module, a locking plate (2) corresponding to the new module is added, and the new locking plate (2) is hinged to the original locking plate chain using the locking linkage (3). At the same time, the new stop button rod (6) is driven to cooperate with the new locking plate (2), thus realizing the functional expansion.

8. The central locking device for an expandable multi-cavity lifting door explosion-proof shell as described in claim 1, characterized in that, The entire central locking device is located outside the explosion-proof enclosure. Its linkage rod (1), locking plate (2), locking connecting rod (3), stop button rod (6) and each connection point are all exposed or visible structures, making it easy to directly observe its operating status.

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