Circuit breaker with thermal bimetal tripping linkage mechanism and control method

Abstract

The invention provides a circuit breaker with a thermal bimetal tripping linkage mechanism and a control method. Comprising a shell, a contact system, an operating mechanism, a locking mechanism, a thermal bimetallic strip overload protection mechanism, an electronic protection module, a mechanical linkage device and a state indicating device, the mechanical linkage device comprises an L-shaped driving lever capable of rotating around a rotating shaft, and the L-shaped driving lever is provided with a first driving arm and a second driving arm; the output end of the thermal bimetallic strip overload protection mechanism is operationally coupled with the first driving arm and is used for driving the first driving arm to enable the L-shaped shifting rod to rotate around the rotating shaft in a first direction during overload; the electronic protection module comprises an electromagnetic tripper, a movable ejector pin of the electromagnetic tripper is operatively coupled with the second driving arm, and the electromagnetic tripper is used for driving the second driving arm to enable the L-shaped shifting rod to rotate around the rotating shaft in a second direction opposite to the first direction during short circuit or electronic protection action; and the indicating piece displays different protection action type identifiers according to different rotation directions of the L-shaped driving lever.

Description

Technical Field

[0001] This invention relates to the field of circuit safety protection technology for precision electromechanical components, and more specifically, to a circuit breaker and control method having a thermal bimetallic trip linkage mechanism. Background Technology

[0002] As a basic circuit protection device, the core function of a circuit breaker is to promptly and reliably interrupt the current when abnormal operating conditions occur in the protected circuit, preventing electrical fires and equipment damage. Abnormal operating conditions include overload, short circuit, or ground fault. Based on its protection principle and execution method, it has mainly undergone the following technological evolution: 1. Pure thermal-magnetic circuit breaker: Its overload protection relies on a thermal bimetallic strip connected in series in the main circuit. When the overload current continues, the bimetallic strip bends due to the different thermal expansion coefficients of the different metal layers, and finally triggers the tripping mechanism through mechanical transmission. Its short-circuit protection relies on an electromagnet (or electromagnetic trip unit). When a large short-circuit current flows through the coil, it generates a sufficiently large electromagnetic force to directly attract or push the armature to trigger the tripping. Its advantages are that it works completely passively, requires no external power supply, has extremely strong anti-interference ability, simple principle, and low cost. Its disadvantages are obvious: thermal protection is greatly affected by ambient temperature, and the action curve has high dispersion; the action value (instantaneous current) of magnetic protection is fixed and the adjustment range is limited, resulting in low accuracy; it cannot achieve complex protection characteristics (including inverse time adjustable, area selective interlocking, etc.); the two mechanisms are usually set up independently, resulting in a dispersed structure. 2. Electronic / Intelligent Circuit Breakers: Emerging with the development of microelectronics technology, these circuit breakers use current transformers (CTs) or Rogowski coils to sample current signals. After analog-to-digital conversion and microprocessor (MCU) processing, they achieve precise current-time (It) characteristic protection. When a fault is detected, the MCU drives a high-performance electromagnetic trip unit or electric operating mechanism to perform the tripping action. Advantages include high protection accuracy and flexible programmable characteristics (including long-delay, short-delay, and instantaneous protection), and the ability to integrate advanced functions such as communication, measurement, and fault recording. Disadvantages include high dependence on a stable power supply and the reliability of electronic components; the risk of electronic module failure in harsh industrial environments such as strong electromagnetic interference (EMI), high temperature, high humidity, and vibration; and the potential complete loss of protection function if the auxiliary power supply is lost. 3. Hybrid protection schemes combining thermomagnetic and electronic methods, commonly implemented in the following forms: Parallel Redundancy Type: The thermomagnetic protection mechanism and the electronic protection module are electrically connected in parallel and mechanically largely independent; both can be triggered to trip independently; although this design provides backup, it may lead to a bulky structure, and in extremely rare cases, the two mechanisms may compete or interfere with each other due to a small time difference or transmission gap, affecting the breaking speed. Electronic main control, thermomagnetic backup type: The electronic module serves as the main protection and control unit, while the thermomagnetic bimetallic strip only acts as the "last line of defense" after the electronic module completely fails. The two may be coordinated through simple mechanical interlocking or electrical interlocking. However, this design often puts thermal protection in a secondary position, and its triggering path may not be direct and reliable enough. Furthermore, the long-term small deformation of the thermomagnetic bimetallic strip during normal operation of the electronic module may pose a safety hazard to the mechanism. These problems still need to be improved and solved. Therefore, it is necessary to propose a circuit breaker and control method with a thermomagnetic bimetallic tripping linkage mechanism to at least partially solve the problems existing in the prior art. Summary of the Invention

[0003] The summary of the invention introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary of the invention does not mean that it attempts to limit the key features and essential technical features of the claimed technical solution, nor does it mean that it attempts to determine the scope of protection of the claimed technical solution. To at least partially solve the above problems, the present invention provides a circuit breaker with a thermal bimetallic trip linkage mechanism, comprising: The housing, contact system, operating mechanism, locking mechanism, bimetallic strip overload protection mechanism and electronic protection module also include mechanical linkage device and status indication device; The mechanical linkage device includes an L-shaped lever that can rotate around a pivot, and the L-shaped lever has a first drive arm and a second drive arm; The output end of the thermal bimetallic strip overload protection mechanism is operably coupled to the first drive arm, and is used to drive the first drive arm to rotate the L-shaped lever around the rotating shaft in the first direction when overloaded. The electronic protection module includes an electromagnetic trip unit, the movable pin of which is operably coupled to the second drive arm, for driving the second drive arm to rotate the L-shaped lever around the pivot in a second direction opposite to the first direction when a short circuit or electronic protection is activated. The L-shaped lever is provided with an output section, which is configured to push the release component of the locking mechanism during rotation in either the first or second direction, causing the locking mechanism to release and driving the contact system to disconnect. The status indicator includes an indicator that is mechanically linked to the L-shaped lever, and an observation window on the housing. The indicator displays different protection action type indicators depending on the rotation direction of the L-shaped lever. The "dual-input-single-output" mechanical fusion tripping linkage mechanism's core idea is to design a single-degree-of-freedom core transmission element (L-shaped lever) that orthogonally couples the slow, large-displacement input from the thermocoupled double metal deformation and the high-speed, small-displacement input from the electromagnetic trip unit to the same rotational motion. This rotational motion directly drives the standard locking mechanism without intermediate links. This design physically ensures absolute non-interference between the two protection paths while ensuring that any action can be effectively transmitted to the execution end. Furthermore, by cleverly utilizing the difference in the motion trajectory of this core transmission element, a simple and reliable mechanical status indicator is driven, achieving "power-off visibility" of the protection action type. This invention is not a simple functional stacking but rather achieves system-level reliability improvement and structural simplification through ingenious mechanical topology optimization. This invention can seamlessly and without interference integrate thermal overload protection and electronic short circuit (and programmable overload) protection, ensuring that in the event of failure of any single protection path, the other path can still independently and completely complete the trip protection function; Another important objective of this invention is to simplify the internal mechanical structure, reduce the number of parts, lower assembly complexity and production costs, and improve product consistency and reliability while achieving the aforementioned dual protection fusion. It also integrates a purely mechanical protection action type indicator device into the circuit breaker, independent of electronic circuits and external power supplies. This device can intuitively and stably display whether the circuit breaker tripped due to "thermal overload protection" or "electronic protection," providing crucial information for on-site fault diagnosis and equipment maintenance. A further objective of this invention is to provide a modular design approach, allowing the electronic protection module to be plugged in, replaced, or upgraded as an independent unit without affecting the integrity of the mechanical thermal protection function, thereby improving product maintainability and lifecycle value. Ultimately, this invention aims to provide a circuit breaker solution that is particularly suitable for harsh industrial environments (including those with strong electromagnetic interference, wide temperature range, high humidity, high dust, and continuous vibration), meeting the extreme reliability requirements of modern industrial control systems for underlying protection devices.

[0004] Invention design scheme: 1. Shell and overall layout: The circuit breaker housing is injection molded from high-insulation, high-strength engineering plastics (including nylon PA66 and polycarbonate PC) or thermosetting materials (including DMC). The interior of the housing is divided into multiple functional chambers: the upper part is the operating mechanism chamber and the arc-extinguishing chamber, the middle part is the contact system and the locking mechanism chamber, and the lower part is the protection mechanism chamber. The mechanical linkage device, as an independent modular component, is installed in the center of the protection mechanism chamber, playing a key role in connecting the upper and lower parts and linking the left and right sides. 2. Specific components of the mechanical linkage device: Core transmission component – ​​L-shaped lever: This part is the core of the invention's functionality; it is typically made of high-strength, wear-resistant engineering plastics (including POM) or metals (including stamped stainless steel); the lever is rotatably supported on a fixed bracket of the housing via a precision shaft; the main body of the lever is approximately "L"-shaped and has two main drive arms: First drive arm (thermal drive arm): This arm is relatively long and has a low-friction structure at the end, such as an embedded miniature roller, a raised arc surface, or a groove coated with lubricating material; this arm maintains constant contact or slight pre-pressure contact with the output end of the thermal bimetallic strip drive assembly. Second drive arm (magnetic drive arm): This arm is shorter and stronger, and its side or end is provided with a force-bearing impact surface; the impact surface is directly opposite to the axial movement trajectory of the electromagnetic trip pin of the electronic protection module; the design of the second drive arm needs to take into account the strength and rigidity to withstand high-speed impacts. Output section: At the corner or a specific position of the L-shaped lever, there is a toggle protrusion or fork; this output section directly acts on the release lever of the locking mechanism; Reset mechanism: A torsion spring mounting post can be installed on the lever, and a torsion spring provides a restoring torque so that the lever remains in a stable intermediate (or initial) position when it is not in operation; Thermo-bimetallic drive assembly: A hot bimetallic strip is connected in series in the main circuit, with its fixed end fixed by a conductive connecting plate; its free end is connected to a transmission plate; the transmission plate converts the bending deformation of the bimetallic strip into linear or arc displacement; the contact method between the transmission plate and the end of the first drive arm of the L-shaped lever is preferably rolling contact or sliding contact with a low friction coefficient material, so as to minimize the resistance to the deformation of the hot bimetallic strip and ensure the accuracy of overload protection. Optionally, a force amplification lever or displacement amplification mechanism can be added to the transmission path to improve the sensitivity to small overload currents. Electromagnetic drive interface of electronic protection module: The electronic protection module is an independent unit that includes a current sensor, signal processing circuit, microcontroller, trip drive circuit, and electromagnetic trip unit; the electromagnetic trip unit is essentially a high-speed solenoid. Its movable part—the ejector pin—is usually made of magnetic material, with an impact head at the front end. The ejector pin is in the retracted position under the action of the spring. When a trip signal is received, the coil is instantly energized, generating a strong electromagnetic force that ejects the ejector pin at high speed. The cooperation between the ejector pin and the second drive arm of the L-shaped lever is a key technical point; there is a small air gap (e.g., 0.5-2mm) between the two when they are static; this air gap ensures that the electromagnetic trip device does not affect the degree of freedom of the lever when it is not activated, and also ensures that the ejector pin can obtain sufficient acceleration distance to generate sufficient impact momentum when activated; non-metallic buffer pads can be set on the ejector pin or lever to absorb impact noise and prevent damage to parts; 3. Detailed design of the status indication device: Indicator transmission mechanism: The present invention utilizes the characteristic that the motion trajectories on both sides of the rotation center of the L-shaped lever are different when it rotates; a preferred embodiment is: an indicator gear or non-circular cam is coaxially mounted on the rotating shaft of the L-shaped lever; a driven rack or swing rod is provided, one end of which meshes or contacts the gear / cam, and the other end is connected to the indicator slider or indicator color wheel; Indicator display unit: An indicator window is opened on the surface of the housing, with a transparent or semi-transparent protective cover embedded in the window; behind the window is the movement channel of the indicator slider; the slider has two different colored blocks (including red and blue), or is directly marked with "THERMAL" and "ELECTRONIC"; the initial position of the indicator slider (when the circuit breaker is normally closed) may be displayed as white or "READY". Action locking mechanism: To ensure that the indicated state remains stable after action and is not affected by vibration or reset operation, the indicating mechanism can be integrated with a simple ratchet-pawl locking mechanism; when the indicating slider moves to the "thermal protection" or "electronic protection" position, the pawl falls into the tooth groove of the ratchet and locks it; reset requires manual release of the lock through a dedicated reset button or reset lever (which can be operated from the outside), so that the indicating mechanism and the L-shaped lever reset synchronously; 4. Locking mechanism and linkage relationship: The locking mechanism adopts a mature four-bar or five-bar linkage trip-lock structure; its trip lever is a sensitive element in the mechanism; the output part (toggle protrusion) of the L-shaped lever is directly opposite the force arm of the trip lever; whether the first drive arm is slowly pushed or the second drive arm is impacted at high speed, the L-shaped lever will rotate around the pivot; this rotational motion causes the toggle protrusion to push the trip lever in almost the same way and along the same trajectory; the rotation of the trip lever releases the constraint on the trip lever, and under the action of the opening spring, the operating mechanism moves quickly, causing the moving contact to separate from the stationary contact, thus completing the opening; 5. Modular design of electronic protection module: To ensure maintainability, the electronic protection module can be designed as a pluggable type; the module housing has standard electrical connectors (for current signal input, auxiliary power supply, trip signal output, etc.) and a mechanical docking guide structure; when the module is inserted into the circuit breaker body, the pin of its electromagnetic trip unit can automatically and accurately align with the impact surface of the second drive arm of the L-shaped lever; the module can also be equipped with a light-transmitting hole for status indicator lights, which is placed alongside the indicator window of the circuit breaker to display the operating status of the electronic module itself (including normal power supply, normal communication, etc.).

[0005] Preferably, the output end of the thermal bimetallic strip overload protection mechanism contacts the end of the first drive arm through a transmission plate, and the contact method is rolling contact or sliding contact of a low-friction coefficient material.

[0006] Preferably, the second drive arm is provided with a buffer pad, and the movable pin of the electromagnetic release device impacts the buffer pad when it is activated.

[0007] Preferably, the status indicator further includes a locking mechanism for mechanically locking its position after the indicator displays the protection action type identifier, preventing it from changing due to vibration or reset operation. The locking mechanism can be released by a dedicated manual operation or a reset operation linked to the operating mechanism.

[0008] Preferably, the status indicator device includes a gear fixed coaxially with the rotating shaft and a rack and pinion slider meshing with the gear, the slider having at least two different colored or patterned marking areas; the locking mechanism includes ratchet teeth on the slider and pawls elastically connected to the housing.

[0009] Preferably, the electronic protection module is a pluggable module, and its housing is provided with a guide mechanism and an electrical connector. When the module is inserted into the circuit breaker body, the movable pin of the electromagnetic trip unit can automatically align with the second drive arm.

[0010] Preferably, the output portion of the L-shaped lever is a toggle protrusion or fork whose movement trajectory intersects with the force arm of the release lever of the locking mechanism, so as to push the release lever when rotating.

[0011] Preferably, the mechanical linkage device further includes a reset elastic element, which applies a torque to the L-shaped lever to bring it toward an intermediate equilibrium position.

[0012] Preferably, the length of the first drive arm is greater than the length of the second drive arm.

[0013] The present invention provides a circuit breaker control method with a thermal bimetallic trip linkage mechanism, comprising: S10, when a current that meets the thermal overload protection characteristics is detected, the deformation of the thermal bimetallic strip drives the L-shaped lever to rotate in the first direction through the first drive arm, triggering the trip, and the status indicator device indicates that the thermal protection action has been activated. S20, when a current that meets the electronic protection characteristics is detected, the electronic protection module triggers the electromagnetic trip unit, whose pin impacts the second drive arm, driving the L-shaped lever to rotate in the second direction, triggering the trip, and the status indicator device indicates that the electronic protection action has been activated. S30, the physical paths of the two protection actions converge at the L-shaped lever, and finally act on the same tripping component through the same output part.

[0014] Compared with the prior art, the present invention has at least the following beneficial effects: This invention discloses a circuit breaker and control method with a thermal bimetallic trip linkage mechanism: two protection signals ultimately converge on an L-shaped lever, a "mechanical OR gate," and drive the same trip point uniformly and unambiguously through its single-degree-of-freedom rotational motion; fundamentally eliminating the possible action competition, timing disorder, or force transmission loss that may occur in the independent transmission of dual systems; Physical isolation and independence: Thermal drive and magnetic drive are physically isolated at the input end; the bending of the thermal bimetal is not affected by the electromagnetic system, and the impact of the electromagnet is not dependent on the position of the thermal system; any fault in one path (including electronic module damage, electromagnet jamming; or thermal bimetal aging, transmission rod jamming) will not block the working path of the other path; realizing the "fail-safe" design concept. Wide adaptability: Thermal protection is completely unaffected by power supply and EMC, while electronic protection provides high precision and speed; the combination of the two covers the entire time range of protection from millisecond-level short circuits to hour-level overloads, and there is always a mechanism to rely on under various environmental disturbances. Visual power failure: The indication is generated and maintained entirely by mechanical movement, without relying on any electronic components or power supply; it can still provide valuable first-hand information about the fault even after a fire or when electronic modules are destroyed; Anti-interference: The mechanical locking mechanism ensures that the indicated status will not change erroneously under strong vibration and impact, avoiding the drawbacks of traditional stickers or simple labels being easily worn and detached; greatly improving the efficiency of troubleshooting. Component integration: The L-shaped lever replaces multiple connecting rods, hinge points, and intermediate transmission parts that may be required in traditional solutions; the core linkage device can be pre-assembled into a module and installed as a whole into the housing, reducing the complexity and time of assembly line assembly; the compact layout frees up internal space in the housing, which can be used to enhance arc extinguishing capability, add auxiliary contacts, or accommodate larger capacity conductive components, which is conducive to product miniaturization or performance improvement. The combination of "mechanical backup and mechanical indication" constitutes a unique product highlight, easily conveying the value proposition of high reliability to users, which is particularly in line with the purchasing preferences of customers in key sectors such as industry and energy; higher reliability reduces unplanned downtime and replacement frequency; intuitive indication reduces maintenance and diagnostic costs; this mechanical linkage platform is compatible with different specifications of thermal bimetallic modules and electronic modules with different performance characteristics; it is a significant innovation.

[0015] The circuit breaker and control method with a thermal bimetallic trip linkage mechanism described in this invention will have other advantages, objectives and features that will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention, but do not constitute a limitation thereof; in the drawings: Figure 1 This is a diagram of an embodiment of a circuit breaker with a thermal bimetallic tripping linkage mechanism according to the present invention.

[0017] Figure 2 This is a diagram of an embodiment of the circuit breaker control method with a thermal bimetallic tripping linkage mechanism according to the present invention. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, so that those skilled in the art can implement it based on the description; for example Figure 1 As shown, the present invention provides a circuit breaker with a thermal bimetallic tripping linkage mechanism, comprising: The housing 11, contact system 12, operating mechanism 13, locking mechanism 14, hot bimetallic strip overload protection mechanism 15, and electronic protection module 16, also include mechanical linkage device 17 and status indication device 18; The mechanical linkage device includes an L-shaped lever that can rotate around a pivot, and the L-shaped lever has a first drive arm and a second drive arm; The output end of the thermal bimetallic strip overload protection mechanism is operably coupled to the first drive arm, and is used to drive the first drive arm to rotate the L-shaped lever around the rotating shaft in the first direction when overloaded. The electronic protection module includes an electromagnetic trip unit, the movable pin of which is operably coupled to the second drive arm, for driving the second drive arm to rotate the L-shaped lever around the pivot in a second direction opposite to the first direction when a short circuit or electronic protection is activated. The L-shaped lever is provided with an output section, which is configured to push the release component of the locking mechanism during rotation in either the first or second direction, causing the locking mechanism to release and driving the contact system to disconnect. The status indicator includes an indicator that is mechanically linked to the L-shaped lever, and an observation window on the housing. The indicator displays different protection action type indicators depending on the rotation direction of the L-shaped lever.

[0019] The present invention provides a circuit breaker control method with a thermal bimetallic trip linkage mechanism, comprising: S10, when a current that meets the thermal overload protection characteristics is detected, the deformation of the thermal bimetallic strip drives the L-shaped lever to rotate in the first direction through the first drive arm, triggering the trip, and the status indicator device indicates that the thermal protection action has been activated. Working principle and process 1. Normal working status: The circuit current is within the rated range, the bimetallic strip shows no significant deformation, and the transmission plate exerts no force on the first drive arm of the L-shaped lever; the electronic protection module monitors the current as normal, and the electromagnetic trip unit does not operate; the L-shaped lever is in the predetermined intermediate equilibrium position under the action of the reset torsion spring; the locking mechanism is securely locked, and the circuit breaker is in the "closed" state; the indicator window displays "normal" (including green or white). S20, when a current that meets the electronic protection characteristics is detected, the electronic protection module triggers the electromagnetic trip unit, whose pin impacts the second drive arm, driving the L-shaped lever to rotate in the second direction, triggering the trip, and the status indicator device indicates that the electronic protection action has been activated. 2. Overload protection operation process: When the circuit is overloaded (including 1.2-10 times the rated current) and this overload continues for a period of time, the hot bimetallic strip will slowly bend due to Joule heating. Displacement transmission: The bending of the bimetallic strip pushes the transmission plate, which applies a continuously increasing force to the first drive arm of the L-shaped lever in a rolling / sliding manner; Rotation of the lever: The torque generated by this force overcomes the torque of the return torsion spring, driving the L-shaped lever to rotate about the axis in a first direction (e.g., clockwise); Triggering trip: As the lever rotates, the actuating protrusion on it contacts and pushes the trip lever; when the torque reaches the release threshold of the locking mechanism, the trip lever rotates, the trip is released, and the operating mechanism quickly opens the circuit under the drive of the energy storage spring; Status indicator linkage: While the lever rotates, the rack-slider mechanism moves through the coaxial indicator gear; due to the rotation caused by the action of the thermally driven arm, the slider moves to a specific position, pushing the red "overload" color block to the bottom of the indicator window and locking it by the pawl mechanism; Result: The circuit was cut off, and the window displayed red, clearly indicating that the trip was caused by thermal overload protection. S30, the physical paths of the two protection actions converge at the L-shaped lever, and finally act on the same tripping component through the same output part; 3. Short circuit (or electronic protection) operation process: When a short circuit occurs in the line or the instantaneous protection threshold set by the electronic module is reached, the electronic protection module completes the judgment within milliseconds. Signal trigger: The microcontroller sends a trip command, and the drive circuit applies a large current pulse to the electromagnetic trip coil; High-speed impact: The electromagnetic trip pin accelerates to high speed within milliseconds, crosses the reserved air gap, and violently impacts the impact surface of the second drive arm of the L-shaped lever; Lever rotation: The enormous impact force generates an instantaneous strong torque, causing the L-shaped lever to rotate at high speed around the axis in a second direction opposite to the first direction (e.g., counterclockwise); this process is extremely fast, much faster than the inherent response time of the mechanical mechanism; Triggering the trip: The rapid rotation of the lever also causes the protrusion to violently impact the trip lever, forcing the locking mechanism to release instantly and achieving high-speed disconnection (the total disconnection time can be as low as less than 20ms). Status indicator linkage: The counterclockwise rotation of the lever drives the indicator slider to move in the other direction through the indicator mechanism (gear rack and pinion or cam lever), pushing the blue "short circuit / electronic" block to the bottom of the indicator window and locking it; Result: The circuit was cut off at high speed, and the window displayed blue, clearly indicating that the trip was triggered by the electronic protection function; 4. Reset process: After troubleshooting, the operator moves the handle to the "open" position and then performs the "close" operation. During the "opening" process, the movement of the operating mechanism usually drives a reset lever, which can first release the pawl lock of the status indicator mechanism; Subsequently, when the mechanism moves to a specific position, the reset lever or another protrusion will push the L-shaped lever back to the middle position; at this time, the hot bimetallic strip has cooled and reset, and the pressure on the first drive arm has disappeared; the electromagnetic trip pin has also retracted under the action of its own spring. The lever resets, causing the indicator slider to return to its initial "normal" display position; At this point, the circuit breaker has been fully reset and can be closed again.

[0020] One example: Standard molded case circuit breaker

[0021] This embodiment uses a three-pole molded case circuit breaker with a rated current of 100A as an example; 1. Overall structure: The circuit breaker housing consists of a base and a top cover; the three-phase contact system and arc-extinguishing chamber are arranged in parallel; the operating mechanism is a spring-energy-storage quick-acting mechanism; the locking mechanism is located at the center of the mechanism; 2. Detailed description of the mechanical linkage device: L-shaped lever: Made of SUS304 stainless steel sheet, stamped and formed with a thickness of 2mm; the whole is in the shape of a 90° right angle L; the long arm (first drive arm) is about 25mm long, and a hemispherical protrusion is stamped at the end as the contact point with the transmission plate; the short arm (second drive arm) is about 12mm long, and a small polyurethane buffer block is welded on its side as the impact surface; a trapezoidal toggle protrusion is stamped on the inside of the corner; Shaft and bracket: The lever is mounted on an integrated nylon bracket via a 3mm diameter hardened steel shaft; the bracket is fixed to the housing base with screws. Returning torsion spring: A torsion spring is sleeved on the rotating shaft, with one end locked on the bracket and the other end locked in the spring hanging hole of the lever, providing a restoring torque of about 0.05 N·m to stabilize the lever in the middle position; 3. Thermal protection components: Each bimetallic strip is connected in series in the main circuit of the phase via a conductive plate; the free ends of the three bimetallic strips are connected together to a three-phase balanced transmission plate; the transmission plate then gathers the force into a total transmission plate; a ceramic ball is embedded at the end of the total transmission plate, which forms point contact rolling friction with the hemispherical protrusion of the first drive arm of the L-shaped lever; this design greatly reduces hysteresis and improves the consistency of thermal protection. 4. Electronic protection module: It is a standalone black plastic module that is inserted into the side of the housing via a guide rail. The module integrates a three-phase current transformer, an ARM Cortex-M0 core MCU, a supercapacitor backup power supply, and a high-impact electromagnetic trip unit. The trip unit's pin is a 4mm diameter steel cylinder with a pop-out stroke of about 5mm and a static air gap of 1.5mm. The front panel of the module has LED indicator lights and a test button. 5. Status indication device: At one end of the L-shaped lever shaft that extends out of the bracket, a miniature plastic indicator gear with one tooth is press-fitted. An indicator rack and slider is horizontally mounted in a guide groove, with the rack meshing with a gear; The slider has three colored stripes from left to right: green, red, and blue. There is a rectangular indicator window at the corresponding position on the housing. Under normal conditions, the window shows a green band. After thermal activation, the gear rotates clockwise, causing the rack to move to the right, revealing a red band. After electrical activation, the gear rotates counterclockwise, causing the rack to move to the left, revealing a blue band. The rack has serrations on the back, which are engaged by a miniature phosphor bronze pawl to achieve one-way locking; reset is achieved by a reset rod linked to the operating handle, which first disengages the pawl during the opening process; 6. Workflow: Hot action: In case of overload, the three-phase bimetallic strip bends, pushing the main transmission plate; the transmission plate pushes the lever arm, and the lever rotates clockwise against the torsion spring; the lever protrusion pushes the end of the trip lever upward, causing the trip lever to release and the mechanism to open; at the same time, the gear rotates clockwise, the rack moves to the right, the red indicator is exposed and locked; Electrical action: In the event of a short circuit, the electromagnetic trip unit pin strikes the buffer block at extremely high speed, and the lever arm rotates counterclockwise due to the impact. Similarly, the protrusion pushes the trip lever to achieve rapid tripping; the gear rotates counterclockwise, the rack moves to the left, and the blue indicator is exposed and locked.

[0022] One example: Modular programmable circuit breaker

[0023] This embodiment, based on Embodiment 1, focuses on enhancing the intelligence and maintainability of the electronic protection module: 1. Electronic protection module upgrade: The module adopts a fully enclosed metal shell to enhance EMC performance; it provides RS-485 or Ethernet communication interfaces and supports protocols such as Modbus and Profinet; users can accurately set the protection current value, time constant, alarm parameters, etc. of each segment through the host computer software; the module has a fault event recording function, which can store the current waveform, action type (determined by the module itself) and timestamp of the last 10 trips; 2. Synergy between mechanical indication and electronic recording: The module's panel has a small LCD screen that can display current, setting parameters, etc. in real time. When a trip occurs, the LCD screen will light up and display detailed fault information. At the same time, the mechanical indication window 94 will still display red or blue according to the aforementioned principle. This design provides double redundancy for fault information: the electronic record is detailed and accurate, and the mechanical indication is not lost and is clear at a glance. Maintenance personnel can first quickly determine the major category based on the window color, and then read the detailed record through communication for in-depth analysis. 3. On-site fine-tuning of thermal protection parameters: An initial position adjustment screw for the first drive arm is set on the fixed bracket; by rotating the screw, the initial position of the contact point between the transmission plate and the lever arm can be finely adjusted, thereby performing a small-range on-site calibration of the thermal protection action characteristics to compensate for the slight characteristic drift of the bimetallic strip after long-term use or to meet special load requirements. 4. Improved plug-in interface: The interface between the module and the main body adopts a blind plug design with clear color markings and alignment keys to prevent mis-plugging; during plugging and unplugging, there is a protective cover linkage mechanism to ensure that when the module is pulled out, the internal ejector pins and the mechanical parts of the main body are automatically covered, which meets safety standards.

[0024] An example: Specialized design for DC applications

[0025] The principle of this invention also applies to DC circuit breakers; this embodiment is specifically designed for 750V DC systems. Arc extinguishing system: enhanced magnetic blowout and grid arc extinguishing capabilities; thermal bimetallic strip: selected material with more linear DC heating characteristics; electronic protection module: current sensor adopts Hall sensor or shunt, algorithm optimized for DC short circuit (rise rate may be slightly slower); electromagnetic trip coil design adapts to DC power supply; Mechanical linkage device: Considering the potential metal vapor contamination from DC arc, the L-shaped lever material is selected from ceramic-coated metal or special engineering plastics (such as PEEK) that are resistant to arc burning. Indicator colors: can be changed to orange (heat) and yellow (electric) to distinguish it from AC systems.

[0026] Although embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. Other modifications can be easily made by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A circuit breaker with a thermal bimetallic tripping linkage mechanism, characterized in that, include: The housing, contact system, operating mechanism, locking mechanism, bimetallic strip overload protection mechanism and electronic protection module also include mechanical linkage device and status indication device; The mechanical linkage device includes an L-shaped lever that can rotate around a pivot, and the L-shaped lever has a first drive arm and a second drive arm; The output end of the thermal bimetallic strip overload protection mechanism is operably coupled to the first drive arm, and is used to drive the first drive arm to rotate the L-shaped lever around the rotating shaft in the first direction when overloaded. The electronic protection module includes an electromagnetic trip unit, the movable pin of which is operably coupled to the second drive arm, for driving the second drive arm to rotate the L-shaped lever around the pivot in a second direction opposite to the first direction when a short circuit or electronic protection is activated. The L-shaped lever is provided with an output section, which is configured to push the release component of the locking mechanism during rotation in either the first or second direction, causing the locking mechanism to release and driving the contact system to disconnect. The status indicator includes an indicator that is mechanically linked to the L-shaped lever, and an observation window on the housing. The indicator displays different protection action type indicators depending on the rotation direction of the L-shaped lever.

2. A circuit breaker with a thermal bimetallic tripping linkage mechanism according to claim 1, characterized in that, The output end of the bimetallic strip overload protection mechanism contacts the end of the first drive arm through a transmission plate. The contact method is rolling contact or sliding contact of a low-friction coefficient material.

3. The circuit breaker according to claim 1 or 2, characterized in that, The second drive arm is equipped with a buffer pad, and the movable pin of the electromagnetic trip unit impacts the buffer pad when it is activated.

4. A circuit breaker with a thermal bimetallic tripping linkage mechanism according to claim 1, characterized in that, The status indicator device also includes a locking mechanism for mechanically locking its position after the indicator displays the protection action type identifier, preventing it from changing due to vibration or reset operation. The locking mechanism can be released by a dedicated manual operation or a reset operation linked to the operating mechanism.

5. A circuit breaker with a thermal bimetallic tripping linkage mechanism according to claim 4, characterized in that, The status indicator device includes a gear fixed coaxially with the rotating shaft and a rack and pinion slider meshing with the gear. The slider has at least two different colored or patterned marking areas. The locking mechanism includes ratchet teeth on the slider and pawls elastically connected to the housing.

6. A circuit breaker with a thermal bimetallic tripping linkage mechanism according to claim 1, characterized in that, The electronic protection module is a pluggable module, and its housing is equipped with a guide mechanism and an electrical connector. When the module is inserted into the circuit breaker body, the movable pin of the electromagnetic trip unit can automatically align with the second drive arm.

7. A circuit breaker with a thermal bimetallic tripping linkage mechanism according to claim 1, characterized in that, The output portion of the L-shaped lever is a toggle protrusion or fork whose movement trajectory intersects with the force arm of the release lever of the locking mechanism, so as to push the release lever when rotated.

8. A circuit breaker with a thermal bimetallic tripping linkage mechanism according to claim 1, characterized in that, The mechanical linkage device also includes a reset elastic element, which applies a torque to the L-shaped lever to bring it toward an intermediate equilibrium position.

9. A circuit breaker with a thermal bimetallic tripping linkage mechanism according to claim 1, characterized in that, The length of the first drive arm is greater than the length of the second drive arm.

10. A circuit breaker control method with a thermal bimetallic trip linkage mechanism, characterized in that, The circuit breaker control method according to any one of claims 1-9 includes: S10, when a current that meets the thermal overload protection characteristics is detected, the deformation of the thermal bimetallic strip drives the L-shaped lever to rotate in the first direction through the first drive arm, triggering the trip, and the status indicator device indicates that the thermal protection action has been activated. S20, when a current that meets the electronic protection characteristics is detected, the electronic protection module triggers the electromagnetic trip unit, whose pin impacts the second drive arm, driving the L-shaped lever to rotate in the second direction, triggering the trip, and the status indicator device indicates that the electronic protection action has been activated. S30, the physical paths of the two protection actions converge at the L-shaped lever, and finally act on the same tripping component through the same output part.

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