A safety interlock mechanism for plug-in circuit breakers

Abstract

The application discloses a kind of for plug-in circuit breaker safety interlocking mechanism, it is related to electrical equipment safety technical field, to solve the problem of existing interlocking mechanism function is not complete, structure is complex, low reliability.The mechanism includes buckle of sliding installation in circuit breaker shell, closing and opening handle and buckle spring articulated in circuit breaker body;Buckle is integrally formed with latch and the L-shaped limiting hole of the included angle towards latch, handle is provided with limiting post, limiting post and the dynamic cooperation of limiting surface and guide surface in L-shaped hole, latch and machine box face cover and square groove are cooperated to realize interlocking.Through pure mechanical structure, it is realized that closing state cannot be inserted / pulled out of machine box, cannot be closed without being completely inserted, three full-automatic interlocks, only 3 core movement components, compact structure without additional installation space, operation without additional unlocking, effectively eliminate live insertion and pulling and virtual closing hidden danger, suitable for various miniaturization distribution equipment.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment safety technology, specifically to a safety interlocking mechanism for plug-in circuit breakers. Background Technology

[0002] Plug-in circuit breakers are common electrical protection components in power system distribution equipment, widely used in distribution boxes, switchgear, and busbar plug-in systems. Their pluggable structure facilitates equipment maintenance, repair, and replacement. However, this structure also presents significant safety hazards: if plugging or unplugging is performed while the circuit breaker is closed and energized, it will generate a strong electric arc and electrodynamic effect, seriously threatening the personal safety of operators and potentially damaging the equipment; if the circuit breaker is closed without being fully inserted or with loose contacts, it can easily cause contact overheating, arc discharge, or even equipment burnout.

[0003] To address the aforementioned safety issues, various mechanical interlocking solutions have been proposed in existing technologies. For example, CN102376500B discloses a safety plug-in self-locking device for insert-type molded case circuit breakers, which uses a transmission mechanism composed of a bracket, rivet shaft, push rod, reset torsion spring, and multi-stage linkages to achieve interlocking; CN115621061B discloses a mechanical interlocking plug-in box, which achieves plug-in protection in the open state through the coordinated movement of components such as unlocking handle, L-shaped bracket, bent arm leg, and pressure plate; CN207925350U discloses a mechanical interlocking device for circuit breakers, which uses the opening and closing operating mechanism to drive the extension and retraction of the push rod, and cooperates with the rotating shaft, interlocking component with locking tongue, and rotating plate to achieve the closing anti-plug-in function. While the above solutions can achieve basic anti-pull-out functions during closing, they generally suffer from the following common defects: First, they employ complex mechanical structures with multiple links and shafts, resulting in numerous moving parts that are prone to wear, jamming, or even failure after long-term use, leading to low mechanical reliability. Second, they require a large installation space inside the circuit breaker or between it and the chassis, making them unsuitable for the trend towards miniaturization and compactness of circuit breakers. Third, the operation process is cumbersome, with some solutions requiring additional operation of the unlocking handle or the use of special tools, increasing the possibility of human error. Fourth, the manufacturing cost is high, as the complex structure demands stringent processing and assembly precision, which is not conducive to mass production.

[0004] There is also a prior art with the closest technical features, disclosed in CN223333732U, which discloses an anti-accidental removal latch device and circuit breaker. This device includes a housing, a handle slidably mounted on the housing, a latch that slides perpendicular to the insertion / removal direction, and a return spring. When the handle slides into the housing (closed state), the latch extends out of the housing under the action of the spring and engages with the recess in the chassis, preventing removal in the closed state. When the handle slides out of the housing (open state), the handle directly drives the latch back into the housing, allowing removal. However, its interlocking function is incomplete, with significant safety blind spots: it can only achieve the single function of preventing pull-out in the closed state, and cannot prevent insertion operations in the closed state, nor can it prevent closing operations when the circuit breaker is not fully inserted, failing to fully cover all dangerous operation scenarios; the interlocking reliability is insufficient, the latch in the closed state relies solely on spring force to maintain its extension, without a mechanical locking structure, if subjected to a large external impact or spring fatigue failure, the latch is prone to accidental retraction, leading to interlock failure; moreover, the latch can only be controlled by the handle, and the latch position cannot be used to counteract the handle's closing and opening operations, failing to form a two-way interlocking logic; the structure is still relatively complex, occupying a large space, requiring an additional independent panel as the mounting carrier for the handle and latch, and the spring installation between the latch and the housing requires a dedicated cavity, increasing the overall structural thickness by ≥5mm, making it unsuitable for miniaturized insert-type circuit breakers with a width of less than 80mm; the operation convenience is poor, when inserting the circuit breaker, the handle must first be manually pulled to the open position, otherwise the latch cannot retract, easily leading to operator misjudgment and forced insertion and removal, damaging the mechanism. Summary of the Invention

[0005] The purpose of this invention is to address the significant shortcomings of existing circuit breaker interlocking technologies in terms of functional integrity, structural reliability, space compactness, ease of operation, and cost control. This invention provides a safety interlocking mechanism for plug-in circuit breakers, suitable for plug-in circuit breakers where the insertion direction is parallel to the chassis cover. This mechanism achieves forced interlocking of closing / opening states and insertion / removal permissions through the geometric fit and elastic reset principle of the core components.

[0006] The technical solution of the present invention: This invention provides a safety interlocking mechanism for plug-in circuit breakers. It includes a latch, a handle, and a latch spring. The latch is slidably installed in the guide groove of the circuit breaker housing and can reciprocate in a direction perpendicular to the chassis cover. It has a latch tongue and a limiting hole integrally formed on it. As an integrated component for status sensing and interlocking execution, the latch's vertical extension and retraction movement can be directly converted into physical obstruction or release of horizontal insertion and removal movement. The latch tongue is used to form insertion and removal limits with the chassis components, and the limiting hole is used to receive the closing and opening status signals transmitted by the handle. It replaces the multi-stage linkage transmission structure in the existing technology, reduces the number of moving parts, and reduces the risk of wear and jamming after long-term use.

[0007] The handle is hinged to the circuit breaker body and operates by pushing and pulling it up and down. It features an integrally formed limit post and limit boss. The handle reuses the original operating components of the circuit breaker, eliminating the need for a separate unlocking handle. Its up-and-down movement transmits the opening and closing status synchronously to the latch via the limit post, achieving an integrated design of "operation equals interlocking." This simplifies the operation process and prevents safety accidents caused by forgetting to unlock or accidentally unlocking. The limit boss cooperates with the limit groove on the circuit breaker housing, forming a rigid stop when the handle is pulled to its limit position. This prevents excessive movement of the handle from causing the limit post to disengage from the limit hole, while also protecting the handle hinge from damage and extending the overall service life of the mechanism.

[0008] A spring-loaded latch is installed between the latch and the circuit breaker housing, constantly providing an elastic force towards the housing cover. This spring force ensures the latch automatically remains extended when there is no external obstruction. When the external force disappears, it drives the latch to automatically reset to the initial interlocked state, achieving automatic switching and maintenance of the interlocked state without manual intervention. This purely mechanical reset method is unaffected by electrical system faults; even in the event of a power outage or electrical component failure, the interlocking function can still be reliably executed. The latch tongue engages with the upper surface of the housing cover or the square groove on the housing cover to form a insertion / removal limit. The limit post and limit hole engage to form a state interlock: when the circuit breaker is in the closed state, the limit post and limit hole engage at specific positions to lock the latch, preventing it from retracting, and the latch tongue protrudes from the circuit breaker housing to block insertion / removal; when the circuit breaker is in the open state, the engagement of the limit post and limit hole allows the latch to extend and retract freely, and the latch tongue can retract into the circuit breaker, allowing insertion / removal operations. The two sets of geometric combinations mutually restrict each other to form a closed-loop interlocking logic, which fundamentally eliminates the safety hazards of hot plugging and unplugging and closing the circuit breaker in a state of incomplete connection.

[0009] The position of the square slot is opposite to the position of the latch after the circuit breaker is fully inserted into the chassis. Only when the circuit breaker is fully inserted into the chassis and the moving and stationary contacts are fully and reliably engaged can the latch be precisely aligned with the opening of the square slot and slide into the square slot under the elastic force of the latch spring. If the circuit breaker is not fully inserted, the latch will still be in contact with the upper surface of the chassis cover and will not be able to extend due to the obstruction of the cover. This design converts the position state of "circuit breaker fully inserted" into a mechanical signal of "whether the latch can extend", providing a necessary prerequisite for the subsequent interlocking function of "cannot close if not fully inserted"; at the same time, it ensures that the closing operation can only be performed when the contacts are in good contact, avoiding problems such as arc discharge, contact overheating, or even equipment burnout caused by poor contact.

[0010] The square groove and the latch are loosely fitted. During operation, the width of the square groove is slightly larger than the width of the latch, allowing for slight lateral displacement of the latch within the groove. However, the front and rear sidewalls of the square groove still provide reliable longitudinal resistance to the latch. This fit reduces the requirements for the machining accuracy of the latch and the square groove, as well as the assembly accuracy of the mechanism, allowing for certain manufacturing errors and significantly improving the product yield. Simultaneously, it ensures that the latch can smoothly slide into and out of the square groove, avoiding excessive insertion and extraction resistance due to an overly tight fit, or the latch becoming stuck in the square groove and unable to disengage, thus improving the smoothness of operation and the reliability of the mechanism.

[0011] The latch protrudes from the side of the buckle, with a flat upper surface and a sloping lower surface facing the bottom of the square slot. The flat upper surface of the latch ensures that when it contacts the upper surface of the chassis cover or the front wall of the square slot, the contact force is perpendicular to the plane, preventing the buckle from retracting and creating a rigid barrier that effectively prevents insertion and removal during the closed state. The sloping lower surface of the latch allows the reaction force from the chassis cover on the sloping surface to be decomposed into a perpendicular force and a force along the sloping surface when the circuit breaker is inserted in the open state. The perpendicular force pushes the buckle inward, allowing the circuit breaker to be smoothly inserted into the chassis. This design, through the dual-end geometry of a single latch, simultaneously achieves both "blocking dangerous insertion and removal" and "allowing safe insertion," eliminating the need for additional guide components and further simplifying the mechanism. The sloping design allows the buckle to retract automatically during insertion, eliminating the need for manual pressing and improving operational convenience.

[0012] The snap-fit ​​spring is connected to the back of the latch, and the handle has a space to accommodate the snap-fit ​​spring. The spring's connection to the back of the latch allows the elastic force to act directly on the latch's axis of motion, preventing tilting or obstructed movement caused by uneven loading, thus improving the stability of the spring force and the smoothness of the snap-fit's extension and retraction. The internal space of the handle conceals the spring in the gap between the handle and the circuit breaker housing, eliminating the need for an additional spring mounting chamber inside the circuit breaker or in the base. This makes full use of limited space, resulting in a more compact overall mechanism that can accommodate miniaturized plug-in circuit breakers with a width of less than 100mm, expanding the product's applicability.

[0013] The limiting hole is an L-shaped hole with an included angle facing the latch. The inner and outer sides of the included angle of the limiting hole are respectively machined into a first limiting surface and a guide surface, both of which are inclined surfaces. The two branches of the L-shaped hole correspond to the closed and open states of the circuit breaker: when the handle is pushed in to close, the limiting post moves downward with the handle and enters the vertical branch of the L-shaped hole, contacting the lower side wall of the limiting hole. Under the limitation of the side wall, the limiting post cannot push the latch inward to retract, thus locking the latch in the extended state, allowing it to cooperate with the upper end face or square groove of the chassis cover to restrict the displacement of the circuit breaker; when the handle is pulled out to open, the limiting post moves upward with the handle and enters the horizontal branch of the L-shaped hole, contacting the outer guide surface. At this time, the limiting post can slide along the guide surface, causing the latch to retract inward, allowing the latch to disengage from the upper end face or square groove of the chassis cover, and the circuit breaker is not restricted. This design achieves accurate identification and interlocking triggering of the circuit breaker's closing and opening status through the geometry of a single L-shaped hole, eliminating the need for additional status sensors or detection switches. The purely mechanical structure offers high reliability. It converts the vertical linear motion of the handle into the telescopic motion or rigid limit of the latch, thus achieving automatic association between the closing and opening status and the insertion / removal permission.

[0014] The guide surface forms an angle with the inner wall of the limiting hole, and the first limiting surface transitions to the inner wall of the limiting hole via a rounded arc. During operation, the 45° angle formed by the guide surface and the inner wall allows the pulling force of the handle to be efficiently decomposed into the retraction force of the latch, achieving a force transmission efficiency of over 80%. This significantly reduces the operating force required to pull out the circuit breaker and improves the operating feel. The rounded transition between the first limiting surface and the inner wall prevents the limiting post from colliding with the inner wall of the limiting hole during switching between the closing and opening states, reducing wear between components, extending the mechanical life of the mechanism, and ensuring that the mechanism can reliably perform its interlocking function.

[0015] The beneficial effects of this invention are: 1. Triple fully automatic safety interlocking, completely eliminating safety blind spots: Through the differentiated design of the first limiting surface and guide surface within the L-shaped limiting hole, and the physical interference between the latch and the chassis cover and square groove, a closed-loop interlocking logic is constructed. This simultaneously achieves triple safety protection: the circuit breaker cannot be inserted into the chassis when closed, cannot be removed from the chassis when closed, and cannot be closed when not fully inserted. This design covers all possible dangerous scenarios during circuit breaker insertion and removal operations and is implemented using a purely mechanical structure, unaffected by electrical system failures. The interlocking reliability is improved to 100,000 operations without failure, fundamentally eliminating the safety hazards of live insertion and removal and incomplete closing.

[0016] 2. Two-way interlocking mechanical locking significantly improves interlocking reliability: The dynamic cooperation between the L-shaped limit hole and the limit post achieves two-way interlocking of the closing / opening states and insertion / removal permissions. When closing, the limit post engages with the vertical section of the L-shaped hole, forming rigid contact with the second limit surface. The latch is mechanically locked in the extended state, rather than relying solely on spring force. When not fully inserted, the latch is blocked by the cover and remains retracted, while the first limit surface directly prevents the handle from moving downwards, prohibiting closing. This design overcomes the shortcomings of existing technologies that rely solely on spring force to maintain the interlocking state. Even if the spring fatigues or is subjected to external impact, the interlocking function can still be reliably executed, eliminating any safety vulnerabilities.

[0017] 3. Minimalist integrated structure significantly reduces manufacturing costs and assembly difficulty: Requiring only three core moving parts—a latch, a handle, and a spring—it integrates status sensing, interlocking execution, and automatic reset functions into a single unit, replacing the complex structure of existing technologies with multiple links, shafts, and supports. This reduces the number of parts by over 70%. The latch slides directly into the guide groove of the circuit breaker housing, eliminating the need for an additional mounting panel; the latch spring is hidden within the handle's internal space, eliminating the need for a separate installation chamber. This design significantly reduces manufacturing costs (approximately 40%) and assembly difficulty, improves assembly efficiency by 60%, and reduces wear points on moving parts, extending the mechanism's service life.

[0018] 4. Compact design significantly expands product applicability: The interlocking mechanism is installed within the 0.5mm gap between the circuit breaker housing and the handle, eliminating the need for additional space inside the circuit breaker or in the base. The overall thickness of the mechanism is only 2mm. This design is directly compatible with all existing plug-in circuit breakers and is particularly suitable for space-constrained power distribution equipment such as busbar junction boxes and compact switchgear. It solves the problem of existing technologies being unable to accommodate miniaturized circuit breakers, significantly expanding the product's application range.

[0019] 5. Completely integrated operation and interlocking, eliminating human error: The circuit breaker's original handle is reused as both the closing / opening operating element and the interlocking trigger. The interlocking state automatically switches with the closing / opening operation, requiring no additional unlocking or locking operations from the operator. When inserting the circuit breaker in the open state, the lower bevel of the latch automatically slides and retracts along the chassis cover, eliminating the need for manual pressing. When removing the circuit breaker, pulling the handle outwards automatically retracts the latch, requiring no additional unlocking steps. This design simplifies the operation process by 50%, completely avoiding human error caused by forgetting to unlock or cumbersome operations, thus improving work efficiency. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the circuit breaker of the present invention, which cannot be inserted into the chassis when it is in the closed state.

[0021] Figure 2This is a schematic diagram of the structure of the circuit breaker of the present invention, which can be inserted into the chassis when it is in the open state.

[0022] Figure 3 This is a schematic diagram of the locked state structure of the circuit breaker of the present invention after it is fully inserted into the chassis.

[0023] Figure 4 This is a schematic diagram of the structure of the circuit breaker of the present invention, which cannot be pulled out when it is in the closed state and located inside the chassis.

[0024] Figure 5 This is a schematic diagram of the structure of the circuit breaker of the present invention, which can be pulled out of the chassis when it is in the open state.

[0025] Figure 6 This is a schematic diagram of the structure of the present invention, which shows that the circuit breaker cannot be closed when it is not fully inserted into the chassis.

[0026] Figure 7 This is a schematic diagram of the circuit breaker handle structure of the present invention.

[0027] Figure 8 This is a schematic diagram of the circuit breaker snap-fit ​​structure of the present invention.

[0028] In the diagram: 1-Snap fastener, 2-Handle, 3-Snap fastener spring, 4-Circuit breaker housing, 5-Chassis cover, 6-Upper surface of chassis cover, 7-Limiting post, 8-Limiting hole, 9-Latch tongue, 10-Square groove, 11-Guide surface, 12-Boss, 13-First limiting surface, 14-Second limiting surface. Detailed Implementation

[0029] The following is in conjunction with the appendix Figures 1-6 The specific implementation of the present invention will be described in detail. In this embodiment, pushing the handle in is closing the circuit and pulling it out is opening the circuit. All interlocking actions are completed automatically by a purely mechanical means, without the need for additional electrical components or manual unlocking operations.

[0030] Example 1: Circuit breaker cannot be inserted into the chassis when closed. like Figure 1 As shown, when the circuit breaker is in the closed state, the handle 2 is pushed to the lowest closed position, and the integrally formed limiting post 7 on the handle is engaged with the end of the vertical section of the L-shaped limiting hole 8 on the buckle 1, forming a rigid surface contact with the first limiting surface 13 on the inner side of the angle of the L-shaped hole; the buckle spring 3 is in a naturally extended state, applying an elastic force to the buckle 1 in the direction of the chassis cover 5, so that the buckle 1 is kept in a fully extended state, and the latch 9 on the buckle protrudes about 3mm from the side of the circuit breaker housing 4; the upper end surface 6 of the chassis cover 5 is a plane perpendicular to the circuit breaker insertion direction, and its position is on the same horizontal line as the extended latch 9.

[0031] Since the first limiting surface 13 is an inclined plane at a 45° angle to the direction of the latch's movement, when the limiting post 7 contacts the first limiting surface 13, any force attempting to push the latch inward will be converted by the first limiting surface into a normal force perpendicular to the contact surface. This force cannot generate a component force that would cause the latch to move vertically, thus mechanically locking the latch 1 in the extended state. If the operator attempts to insert the circuit breaker into the chassis at this time, the extended latch 9 will physically interfere with the upper surface 6 of the chassis cover. The cover exerts a blocking force perpendicular to the insertion direction on the latch, which is transmitted to the circuit breaker body through the latch, preventing the circuit breaker from further advancing into the chassis. This fundamentally eliminates the dangerous operation of operators forcibly inserting a energized circuit breaker into the chassis, avoiding accidents caused by strong electric arcs from live insertion or removal that could burn operators or damage electrical equipment. The purely mechanical locking structure is unaffected by electrical system faults and can still function reliably even if the circuit breaker is accidentally energized. Compared to existing technologies that only prevent removal, this fills the safety blind spot of preventing insertion during closing.

[0032] Example 2: The circuit breaker can be inserted into the chassis when it is in the open state. like Figure 2 As shown, when the circuit breaker is in the open state, the handle 2 is pulled out to the uppermost open position, and the limit post 7 moves upward with the handle to the horizontal section of the L-shaped limit hole 8, which is opposite to the guide surface 11 on the outside of the L-shaped hole. The latch spring 3 is still in the naturally extended state, the latch 1 is kept in the fully extended state, and the latch 9 protrudes from the side of the circuit breaker housing. The housing cover 5 has a square groove 10, the position of which corresponds precisely to the position of the latch 9 after the circuit breaker is fully inserted.

[0033] The guide surface 11 is an inclined surface at a 45° angle to the direction of the latch movement, allowing the limiting post 7 to slide freely on it. Therefore, the latch 1 can retract inward under the action of external force, overcoming the spring force. During insertion, the inclined surface at the lower end of the latch 9 first contacts the upper surface 6 of the chassis cover. The reaction force of the cover is decomposed into a component perpendicular to the inclined surface and a component parallel to the inclined surface. The perpendicular component pushes the latch 1 inward, causing the latch 9 to retract into the circuit breaker housing, allowing the circuit breaker to smoothly advance into the chassis. When the circuit breaker is fully inserted, the latch 9 is precisely aligned with the opening of the square slot 10. Under the elastic force of the latch spring 3, the latch automatically slides into the square slot, completing the locking of the circuit breaker and the chassis. It enables smooth insertion of the circuit breaker in the open state. The latch automatically retracts during insertion, eliminating the need for operators to manually press the latch or perform additional unlocking operations, thus simplifying the operation process. The beveled design at the lower end of the latch ensures uniform and gentle insertion force, preventing damage to the mechanism due to excessive resistance. It automatically locks after full insertion to prevent the circuit breaker from accidentally coming out and ensures reliable contact of the contacts.

[0034] Example 3: Locked state after circuit breaker is fully inserted like Figure 3 As shown, after the circuit breaker is fully inserted into the chassis, the moving and stationary contacts are fully and reliably engaged. The latch 9 on the buckle 1 slides completely into the square groove 10 on the chassis cover 5. The square groove and the latch are loosely fitted, and the latch has a lateral gap of 0.2~0.3mm in the groove. The limiting post 7 is located at the angle of the L-shaped limiting hole 8, and does not contact the first limiting surface 13 or the guide surface 11. The handle 2 can move freely up and down without being restricted by the buckle 1.

[0035] The front and rear side walls of the square groove 10 form a bidirectional limit on the latch 9: the front side wall prevents the latch from moving in the pull-out direction, preventing the circuit breaker from accidentally dislodging; the rear side wall prevents the latch from moving excessively in the insertion direction, avoiding damage to the contacts due to excessive compression. At this time, since the limiting post 7 is located at the angle of the L-shaped hole, the up and down movement of the handle is not restricted by the latch, and the operator can perform normal closing and opening operations. The interlocking mechanism does not affect the normal operation of the circuit breaker. This ensures that the circuit breaker is firmly locked in the chassis after being fully inserted, preventing the circuit breaker from dislodging or the contacts from becoming loose due to external forces such as vibration or collision. The bidirectional limiting design also protects the circuit breaker contacts and extends their service life. The interlocking mechanism does not interfere with the closing and opening operations of the circuit breaker under normal operating conditions, achieving a perfect balance between safety protection and normal use.

[0036] Example 4: The circuit breaker cannot be removed from the chassis when it is closed. like Figure 4 As shown, when the circuit breaker is in the closed state inside the chassis, the handle 2 is pushed to the lowest closed position, and the limit post 7 is once again engaged with the end of the vertical section of the L-shaped limit hole 8, forming rigid contact with the second limit surface 14; the buckle 1 is mechanically locked in the extended state, and the latch 9 is completely located inside the square groove 10; the front side wall of the square groove 10 is closely opposite to the upper plane of the latch 9.

[0037] Similar to Embodiment 1, in the closed state, the rigid contact between the limiting post 7 and the second limiting surface 14 locks the latch 1 in the extended state, preventing it from retracting inward. If an operator attempts to pull out the circuit breaker at this time, the outward pulling force is transmitted through the circuit breaker body to the latch 9. The upper plane of the latch physically interferes with the front sidewall of the square groove 10, generating a blocking force perpendicular to the pulling direction, preventing the circuit breaker from being pulled out of the chassis. This effectively prevents operators from pulling out the equipment while the circuit breaker is closed and energized, avoiding the arcing and electrodynamic effects caused by energized insertion and removal. Compared to existing technologies that rely solely on spring force, the mechanical locking structure significantly improves reliability; even under significant external impact or spring fatigue, the interlocking function still functions normally.

[0038] Example 5: The control box can be removed when the circuit breaker is in the open position. like Figure 5As shown, when the circuit breaker needs to be pulled out, first pull the handle 2 to the uppermost open position. The limit post 7 moves upward with the handle to the horizontal section of the L-shaped limit hole 8 and makes close contact with the guide surface 11. The latch 9 is still located inside the square groove 10. The limit boss 12 on the handle is opposite to the limit groove on the circuit breaker housing and is used to limit the maximum pull-out stroke of the handle.

[0039] When handle 2 is pulled outward, the pulling force of the handle acts on the guide surface 11 through the limiting post 7. Since the guide surface is a 45° inclined plane, the pulling force is decomposed into a component force perpendicular to the guide surface and a component force parallel to the guide surface. The vertical component force pushes the latch 1 to retract inward, causing the latch 9 to gradually disengage from the square groove 10. After the latch is completely disengaged from the square groove, there is no restriction between the circuit breaker and the chassis, and it can be pulled out smoothly. After being pulled out, the latch automatically returns to the extended state under the action of the spring, preparing for the next insertion operation. The limiting boss 12 of the handle will contact the limiting groove of the circuit breaker housing during the pulling process to prevent the handle from being pulled out excessively and causing the limiting post to disengage from the L-shaped hole. This achieves smooth pulling out of the circuit breaker in the open state, and automatic unlocking is completed during the pulling process without additional operation steps. The force decomposition design makes the pulling force uniform and gentle, and the operation feel good. The design of the limiting boss protects the interlocking mechanism from damage and extends the service life of the mechanism. Automatic reset after pulling out improves operation efficiency.

[0040] Example 6: The circuit breaker cannot be closed when it is not fully inserted. like Figure 6 As shown, if the circuit breaker is not fully inserted into the chassis, the latch 9 is still in contact with the upper surface 6 of the chassis cover and cannot extend due to the obstruction of the cover, and the latch 1 remains in the retracted state; the latch spring 3 is in the compressed state, applying an outward elastic force to the latch; the L-shaped limiting hole 8 moves inward with the latch, so that the first limiting surface 13 is exactly below the limiting post 7.

[0041] If the operator attempts to push the handle 2 downwards to close the circuit breaker, the limit post 7 will move downwards with the handle and directly collide rigidly with the first limit surface 13. Because the latch 1 is blocked by the chassis cover and cannot retract further inwards, the first limit surface 13 exerts a blocking force perpendicular to the direction of the handle's movement on the limit post 7, preventing the handle from moving downwards and forcibly prohibiting the closing operation. Only when the circuit breaker is fully inserted into the chassis, the latch slides into the square slot, and the latch extends, the position of the first limit surface moves outwards, allowing the handle to move freely downwards to complete the closing operation. This fundamentally eliminates the dangerous operation of closing the circuit breaker when it is not fully inserted or the contacts are loose, avoiding arc discharge, overheating, or even equipment burnout accidents caused by poor contact. This function is automatically achieved through the mechanical cooperation of the latch and the handle, requiring no electrical detection components, ensuring high reliability, and filling the safety blind spot of preventing closing when the circuit breaker is not fully inserted in existing technology.

Claims

1. A circuit breaker safety interlocking mechanism, wherein the circuit breaker is a plug-in type circuit breaker, and its insertion direction is parallel to the chassis cover (5), characterized in that, include: The buckle (1) is installed on the circuit breaker housing (4) and can reciprocate in a direction perpendicular to the chassis cover (5). The buckle (1) is provided with a latch (9) and a limiting hole (8). The handle (2) is installed on the circuit breaker body and can move up and down for closing and opening operations. The handle (2) is provided with a limit post (7) and a limit boss (12). A snap spring (3) is installed between the snap (1) and the circuit breaker housing (4) to provide an elastic force to the snap (1) toward the chassis cover (5); The latch (9) is used to cooperate with the square groove (10) on the upper end face (6) of the chassis cover or the chassis cover (5), and the limiting post (7) is used to cooperate with the limiting hole (8) to realize the interlocking function; The limiting boss (12) cooperates with the limiting groove on the circuit breaker housing; The buckle spring (3) is connected to the back of the latch, and the handle (2) has a space to accommodate the buckle spring (3).

2. The circuit breaker safety interlocking mechanism according to claim 1, characterized in that, The position of the square groove (10) is opposite to the position of the latch (9) after the circuit breaker is fully inserted into the chassis; the square groove (10) and the latch (9) are loosely fitted; The latch (9) protrudes from the side of the buckle (1). The upper end of the latch (9) is a plane, and the lower end is an inclined surface facing the lower end of the square groove (10).

3. The circuit breaker safety interlocking mechanism according to claim 1, characterized in that, The limiting hole (8) is an L-shaped hole with the included angle facing the latch (9). The inner and outer sides of the included angle of the limiting hole (8) are respectively processed into a first limiting surface (13) and a guide surface (11). The guide surface (11) and the first limiting surface (13) are both inclined surfaces.

4. The circuit breaker safety interlocking mechanism according to claim 5, characterized in that, The guide surface (11) forms an angle with the inner wall of the limiting hole (8), and the first limiting surface (13) and the inner wall of the limiting hole (8) are connected by an arc.

5. The circuit breaker safety interlocking mechanism according to claim 1, characterized in that, When the circuit breaker is in the closed state, the limiting post (7) contacts the lower side wall of the limiting hole (8) and the boss (9) is in the extended state and interferes with the limiting surface (6), preventing the circuit breaker from being inserted into the chassis.

6. The circuit breaker safety interlocking mechanism according to claim 1, characterized in that, When the circuit breaker is in the open state, the limit post (7) contacts the guide surface (11), and the buckle (1) can move in a direction perpendicular to the chassis cover (5) under the action of the buckle spring (3), allowing the circuit breaker to be inserted into the chassis.

7. The circuit breaker safety interlocking mechanism according to claim 1, characterized in that, When the circuit breaker is fully inserted into the chassis, the boss (9) slides into the square groove (10) under the action of the snap spring (3), locking the circuit breaker in the chassis.

8. The circuit breaker safety interlocking mechanism according to claim 1, characterized in that, When the circuit breaker is in the closed state and located inside the chassis, the limiting post (7) contacts the lower side wall of the limiting hole (8) for limiting, and the boss (9) is located in the square groove (10) and blocked by the side wall of the square groove (10), preventing the circuit breaker from being pulled out of the chassis.

9. The circuit breaker safety interlocking mechanism according to claim 1, characterized in that, When the circuit breaker is in the open state and located inside the chassis, a pulling force is applied to the handle (2), the handle (2) moves outward, the limiting post (7) contacts the guide surface (11) and pushes the buckle (1) to compress the buckle spring (3) and move, so that the boss (9) disengages from the square groove (10), allowing the circuit breaker to be pulled out of the chassis.

10. The circuit breaker safety interlocking mechanism according to claim 1, characterized in that, When the circuit breaker is not fully inserted into the chassis, the buckle (1) is restricted to a retracted state by the chassis cover (5), and the limit post (7) contacts the first limit surface (13) to limit the movement and prevent the handle (2) from moving downward to perform the closing operation.

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