Residual-current circuit breaker

Abstract

The utility model discloses a residual-current circuit breaker which comprises a circuit breaker shell, and an operating mechanism, a circuit board and a test button are arranged in the circuit breaker shell. The circuit board comprises an electricity taking circuit and a test circuit, and the electricity taking circuit and the test circuit share one static contact piece; one end of the test spring is electrically connected with the circuit board, the other end of the test spring is located between the test button and the static contact piece and is normally open with the static contact piece, and the test spring is connected with the static contact piece under the driving of the test button; the electricity taking circuit further comprises a movable contact spring, one end of the movable contact spring is electrically connected with the movable contact, and the other end of the movable contact spring corresponds to the static contact piece. The moving contact spring is fixed on the moving contact and / or the contact support and synchronously moves along with the contact support; when the moving contact is in a closed state, the moving contact is in contact with the static contact piece to realize connection of the power taking circuit; when the moving contact is in an on-off state, the moving contact is completely separated from the static contact piece, thereby realizing disconnection of the power taking circuit. The power distribution box has the characteristics of reverse wire inlet function and more compact structure.

Description

Technical Field

[0001] This application relates to the field of circuit breakers, specifically a residual current circuit breaker. Background Technology

[0002] In the field of miniature residual current circuit breakers (RCCBs), a residual current tripping system is often formed using components such as circuit boards and residual current trip units. In a typical RCCB, the circuit board draws power directly from the main circuit where the circuit breaker is located.

[0003] If the user installs the miniature residual current circuit breaker according to the standard wiring method, the circuit board will not be continuously powered when the main contacts open, and the residual current trip unit will not burn out due to being in a energized state for a long time.

[0004] Some users mistakenly connect miniature residual current circuit breakers (RCCBs) in reverse, a practice commonly known as reverse wiring. In this case, even if the main contacts are disconnected, the circuit board will continue to receive power, causing the RCCB to remain energized for an extended period, ultimately leading to its burnout.

[0005] Therefore, to avoid this situation, a circuit breaker with a reverse-current function has been designed in this field. This involves making the power supply structure of the circuit board a mechanical switch. When the moving contact of the circuit breaker contacts the stationary contact, this mechanical switch is activated; when the moving contact separates from the stationary contact, the mechanical switch is deactivated. This achieves the reverse-current function and protects the residual current device (RCD).

[0006] For example, CN202120384452.X discloses the above structure, but the connection between the test button and this reverse-current function in the above patent is not close, which is not conducive to its application in some specific circuit breakers, such as RCBO circuit breakers. For RCBO circuit breakers (a type of residual current circuit breaker), since all components such as the test mechanism, circuit board, zero-sequence current transformer, circuit breaker operating mechanism, instantaneous system, and bimetallic system are concentrated in one circuit breaker, the internal space utilization requirements are relatively high.

[0007] Therefore, how to design a more reasonable circuit breaker with reverse feed function is a question worth considering. Summary of the Invention

[0008] In view of this, the purpose of this application is to overcome the shortcomings of the prior art and to provide a residual current circuit breaker.

[0009] This application provides: a residual current circuit breaker, which includes a circuit breaker housing, and an operating mechanism, a circuit board and a test button are disposed inside the circuit breaker housing;

[0010] The operating mechanism includes a contact support that is rotatably disposed with respect to the circuit breaker housing and a moving contact disposed on the contact support. The moving contact includes a closed state that is in contact with the stationary contact and an open state that is completely separated from the stationary contact.

[0011] The circuit board includes a power supply circuit and a test circuit, and the power supply circuit and the test circuit share a single stationary contact.

[0012] The test circuit also includes a test spring. One end of the test spring is electrically connected to the circuit board, and the other end is located between the test button and the stationary contact and is normally open with the stationary contact. When the test button is actuated, the test spring and the stationary contact are connected.

[0013] The power supply circuit also includes a moving contact spring. One end of the moving contact spring is electrically connected to the moving contact, and the other end of the moving contact spring corresponds to the stationary contact piece. The moving contact spring is fixed on the moving contact and / or the contact support and moves synchronously with the contact support. When the moving contact is in the closed state, it contacts the stationary contact piece to realize the connection of the power supply circuit. When the moving contact is in the open state, it is completely separated from the stationary contact piece to realize the disconnection of the power supply circuit.

[0014] In some embodiments of this application, the test button is located on one side of the contact support; the test spring is a torsion spring, which includes a coil, a first extension, and a second extension; the second extension is soldered to the circuit board to achieve an electrical connection between the test spring and the circuit board; the first extension is bent toward the direction of the test button and abuts against the test button, and the first extension and the stationary contact are normally open, so that the first extension contacts the stationary contact when the test button is activated.

[0015] In some embodiments of this application, the circuit breaker housing includes a first chamber and a second chamber, which are arranged sequentially along the length of the circuit breaker housing; the operating mechanism and test button are arranged in the first chamber, and the circuit board is arranged in the second chamber; the circuit breaker housing has a partition protrusion arranged between the first chamber and the second chamber, and a first groove is provided on the partition protrusion; a ring portion and a first extension portion are arranged in the first chamber, and the second extension portion passes through the partition protrusion through the first groove and is welded to the circuit board, and the size of the first groove is slightly larger than the diameter of the second extension portion.

[0016] In some embodiments of this application, the second extension is formed into a protrusion by continuous bending. In the width direction of the circuit breaker housing, the protrusion is closer to the opening of the first groove than the welding point between the second extension and the circuit board.

[0017] In some embodiments of this application, in the length direction of the circuit breaker housing, the first extension and the second extension are on both sides of the ring portion, and the first extension extends as a whole in the width and height directions of the circuit breaker housing.

[0018] In some embodiments of this application, the stationary contact piece includes a first contact portion, a connecting portion, a second contact portion, and a welding portion that are bent and connected in sequence; the first contact portion is used to cooperate with the moving contact spring, the second contact portion is used to cooperate with the test spring, and the welding portion is used to weld to the circuit board to form an electrical connection; in the height direction of the circuit breaker housing, the first contact portion is higher than the second contact portion; in the width direction of the circuit breaker housing, the first contact portion and the second contact portion are misaligned.

[0019] In some embodiments of this application, one end of the moving contact spring is a fixed end and the other end is a movable end; the moving contact and the contact support are fixed by riveting, the fixed end is connected to the riveting position, and the movable end is used to cooperate with the stationary contact piece.

[0020] In some embodiments of this application, the fixed end is a ring-shaped structure, which is sleeved at the riveting position and forms a fastener during the riveting process.

[0021] In some embodiments of this application, the contact support includes a mounting groove, the movable contact is located in the mounting groove, and a portion of the movable contact spring extends along the groove wall of the mounting groove, which is adjacent to the fixed end.

[0022] In some embodiments of this application, the operating mechanism further includes a latch and a pull rod; a residual current device (RCD) and a bimetallic strip are also provided inside the circuit breaker housing; one end of the pull rod is connected to the latch, and the other end is connected to the actuation rod of the RCD; the middle part of the pull rod is bent to form a driving part, which is located on the deformation trajectory of the bimetallic strip; when the RCD is actuated, it drives the pull rod to unlock the latch; when the bimetallic strip bends, it impacts the driving part, driving the pull rod to unlock the latch.

[0023] The advantages of this application compared to the prior art are:

[0024] By using a single stationary contact for both the power supply circuit and the test circuit, compared to existing technologies (which require separate stationary contacts), this structure saves on the number of parts. It also allows for a closer integration between the test structure and the structure that enables the reverse-feed function, resulting in a more compact internal structure that is better suited for RCBO circuit breakers.

[0025] Secondly, by using a moving contact spring and a stationary contact piece, the reverse line function can be realized, which effectively improves the life of the circuit board and the leakage current trip unit. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A perspective view of a residual current circuit breaker according to an embodiment of this application is shown;

[0028] Figure 2 An internal schematic diagram of a residual current circuit breaker according to an embodiment of this application is shown;

[0029] Figure 3 A schematic diagram of a portion of the circuit breaker housing in an embodiment of this application is shown;

[0030] Figure 4 A schematic diagram of the mechanical switch of the test circuit in an embodiment of this application is shown;

[0031] Figure 5 A schematic diagram of the test spring in an embodiment of this application is shown;

[0032] Figure 6 This application shows a schematic diagram and a partial enlarged view of the test spring after installation in an embodiment of the present application;

[0033] Figure 7 A schematic diagram of the stationary contact piece in an embodiment of this application is shown;

[0034] Figure 8 A schematic diagram of the moving contact spring, contact support, and moving contact in an embodiment of this application is shown;

[0035] Figure 9 This illustration shows a schematic diagram of the moving contact spring and the stationary contact piece after complete separation in an embodiment of this application.

[0036] Figure 10 This illustration shows a schematic diagram of the moving contact spring and the stationary contact piece in an embodiment of this application.

[0037] Figure 11 A diagram showing the connection relationship between the pull rod, bimetallic strip, leakage trip device, and latch in an embodiment of this application is provided. Detailed Implementation

[0038] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0039] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application 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 application.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0041] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0042] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature. Example

[0043] like Figure 1-11 As shown, a residual current circuit breaker, specifically an RCBO circuit breaker, is disclosed. The circuit breaker includes a circuit breaker housing 100, and inside the housing 100 are an operating mechanism, a circuit board 200, a residual current trip unit 300, a bimetallic strip 400, an electromagnetic trip unit, an arc-extinguishing chamber, a test button 710, etc.

[0044] The circuit breaker housing 100 is composed of left and right halves, which form a space inside each other. The left and right halves are fastened by riveting and snap-fitting.

[0045] The circuit breaker housing 100 is divided into a first chamber 110 and a second chamber 120. The first chamber 110 houses the operating mechanism, bimetallic strip 400, electromagnetic trip unit, arc-extinguishing chamber, test button 710, and other components. The second chamber 120 houses the circuit board 200 and residual current device 300. This two-chamber arrangement allows for maximum separation between the two chambers, reducing the impact of high-voltage components (moving and stationary contacts) on low-voltage components (circuit board 200, etc.). The test button 710, test spring 700, and stationary contact are arranged within a portion of the first chamber 110, separated from the rest of the first chamber by insulating ribs.

[0046] The operating mechanism employs a four-bar linkage, a well-known fact in the field, and will not be elaborated upon here. The operating mechanism includes a contact support 500 and a moving contact 600. The contact support 500 is rotatably connected to the circuit breaker housing 100 via a pin. The moving contact 600 is mounted on the contact support 500 and, as the contact support 500 moves, achieves contact and separation with the stationary contact. Here, the moving contact 600 is fixed to the contact support 500 by riveting. The moving contact 600 includes a closed state in contact with the stationary contact and an open state completely separated from the stationary contact.

[0047] The circuit board 200 includes a power supply circuit and a test circuit. Both the power supply circuit and the test circuit use conventional electrical components (e.g., the test circuit includes a test resistor, and the power supply circuit includes rectification, filtering, etc.). This application only improves the mechanical switches of the two circuits (taking the power supply circuit as an example, it involves adding a mechanical switch to the existing power supply circuit), therefore, the composition of the mechanical switches of the two circuits is described in detail below.

[0048] For the two circuits, their mechanical switches share a single stationary contact 750, which is electrically connected to the circuit board 200 (because it is itself a component of both circuits).

[0049] The test circuit also includes a test spring 700, one end of which is electrically connected to the circuit board 200 (e.g., soldered), and the other end is normally open with the stationary contact 750 (remaining in the open state when not in operation). Since the other end of the test spring 700 is located between the test button 710 and the stationary contact 750, when the test button 710 is actuated, the test spring 700 can connect with the stationary contact 750, thereby connecting the test circuit.

[0050] For the power-drawing circuit, it also includes a moving contact spring 800. One end of the moving contact spring 800 is electrically connected to the moving contact 600, and the other end corresponds to the stationary contact 750. The moving contact spring 800 is fixed to the moving contact 600, so its position changes as the position of the contact support 500 changes. Here, when the moving contact 600 is in the closed state, it contacts the stationary contact 750, thus connecting the power-drawing circuit. When the moving contact 600 is in the open state, it completely separates from the stationary contact 750, thus disconnecting the power-drawing circuit. That is to say, the other end of the moving contact spring 800 can only contact the stationary contact 750 during the process of the moving contact 600 changing towards the closed state. Of course, the moving contact spring 800 can also be fixed to the contact support 500, as long as it can form an electrical connection with one end of the moving contact 600.

[0051] In this way, the reverse-feed function can be achieved through the separable moving contact spring 800 and stationary contact piece 750, effectively improving the lifespan of the circuit board 200 and the leakage current trip unit 300. Even if the load end and the power supply end are connected incorrectly, as long as the circuit breaker is tripped, the mechanical switch of the power supply circuit is also in the disengaged state because the moving contact 600 is in the open state, and power cannot be drawn.

[0052] Meanwhile, by using a single stationary contact 750 for both the power supply circuit and the test circuit, compared to existing technologies (which require separate stationary contact 750s), this structure can save on the number of parts and make the test structure and the structure that implements the reverse-feed function more compact, resulting in a more compact internal structure that is better suited to RCBO circuit breakers.

[0053] Here, the test button 710 is located on one side of the contact support 500. Specifically, taking the length L of the circuit breaker housing 100 as an example, the test button 710 is located on the right side of the contact support 500. Here, the test spring 700 is a torsion spring, which includes a coil portion 701, a first extension portion 702, and a second extension portion 703. The first extension portion 702 and the second extension portion 703 are respectively disposed on both sides of the coil portion 701 (on both sides in the length L of the circuit breaker housing 100). The second extension portion 703 is welded to the circuit board 200 to realize the electrical connection between the test spring 700 and the circuit board 200. The first extension portion 702 is bent toward the direction of the test button 710 and abuts against the test button 710. The first extension portion 702 and the stationary contact piece 750 are normally open, that is, the first extension portion 702 contacts the stationary contact piece 750 when the test button 710 is driven.

[0054] This more compact structural arrangement allows the test structure to be more closely integrated with the contact support 500, which is beneficial for the design of the stationary contact 750 structure.

[0055] Here, the circuit breaker housing 100 has a partition protrusion 130, which is arranged between the first chamber 110 and the second chamber 120. A first groove 140 is formed on the partition protrusion 130. The ring portion 701 and the first extension portion 702 are arranged in the first chamber 110. The second extension portion 703 passes through the partition protrusion 130 via the first groove 140 and is welded to the circuit board 200. The size of the first groove 140 is slightly larger than the diameter of the second extension portion 703.

[0056] This design of the first groove 140 and the separating protrusion 130 ensures both the electrical insulation performance at the mounting point of the test spring 700 and the assembly of the test spring 700. Here, the size of the first groove 140 is slightly larger than the diameter of the second extension 703. "Slightly larger" means that the second extension 703 can be inserted into the first groove 140, completing the engagement of the second extension 703. The specific dimensions are determined based on actual usage; in this embodiment, for example, the diameter of the second extension 703 is 0.55 mm, and the groove is 0.6 mm.

[0057] Here, the second extension 703 is a continuously bent component that forms a protrusion 703a. In the width direction D of the circuit breaker housing 100, the protrusion 703a is closer to the opening of the first groove 140 than the welding point between the second extension 703 and the circuit board 200.

[0058] The protrusion 703a is designed to facilitate the disassembly of the second extension 703. At the same time, compared with a straight rod structure, the contact area between the bent structure and the first groove 140 is larger, which is more conducive to improving the installation stability of the second extension 703.

[0059] As for the second extension 703, its general extension direction is along the length direction L of the circuit breaker housing 100 (partial bends extend towards the width direction D of the circuit breaker housing 100, but generally it extends along the length direction L of the circuit breaker housing 100).

[0060] The first extension 702 extends integrally in both the width direction D and the height direction H of the circuit breaker housing 100. That is, the first end of the first extension 702 is connected to the coil 701, and from the first end to the second end of the first extension 702, it extends in a composite direction formed by the width direction D and the height direction H of the circuit breaker housing 100.

[0061] This first extension 702 design is more suitable for the location of the test button 710, avoiding interference with other components in the length direction L of the circuit breaker housing 100.

[0062] The stationary contact 750 comprises a first contact portion 750a, a connecting portion 750b, a second contact portion 750c, and a welding portion 750d. These components are not only connected sequentially but are also bent. Specifically, there is an angle between the first contact portion 750a and the connecting portion 750b, approximately 90° (not limited to 90°, as long as it is between 80-100°); an angle between the connecting portion 750b and the second contact portion 750c, approximately 90° (not limited to 90°, as long as it is between 80-100°); and an angle between the second contact portion 750c and the welding portion 750d, approximately 90° (not limited to 90°, as long as it is between 80-100°).

[0063] Here, the first contact portion 750a is used to cooperate with the moving contact spring 800, the second contact portion 750c is used to cooperate with the test spring 700, and the welding portion 750d is used to weld to the circuit board 200 to form an electrical connection.

[0064] In the height direction H of the circuit breaker housing 100, the first contact portion 750a is higher than the second contact portion 750c. In the width direction D of the circuit breaker housing 100, the first contact portion 750a and the second contact portion 750c are misaligned.

[0065] The structure of the stationary contact 750 allows it to be used with both the moving contact spring 800 and the test spring 700. The structure is very simple and easy to mold.

[0066] For the moving contact spring 800, one end is the fixed end 800a, and the other end is the movable end. The fixed end 800a is fixed at the riveting position M1 between the moving contact 600 and the contact support 500, and the movable end is used to cooperate with the stationary contact piece 750.

[0067] This structural design of the moving contact spring 800 allows the moving contact 600, the moving contact spring 800, and the contact support 500 to be fastened in sequence through a riveting process, which helps to save processing steps and improve production efficiency.

[0068] For the fixed end 800a, there are many shapes. As a preferred option, a ring-shaped structure is adopted. This ring-shaped structure is advantageous for fitting at the riveting position M1, making it easier to fasten the moving contact 600, the moving contact spring 800, and the contact support 500 in one go through riveting.

[0069] The contact support 500 includes a mounting groove 510, within which the moving contact 600 is arranged. The moving contact spring 800 extends along the groove wall 510a of the mounting groove 510, and this portion is adjacent to the fixed end 800a. This structure, where the moving contact spring 800 is adjacent to the fixed end 800a and extends along the groove wall 510a of the mounting groove 510, makes the installation of the moving contact spring 800 more stable and its contact with the stationary contact piece 750 more stable.

[0070] For leakage current tripping, it is achieved by actuating the leakage current trip unit 300. For overload protection, it is achieved by bending the bimetallic strip 400. Both are achieved by the same pull rod 900 driving the latch 550 to rotate.

[0071] Here, the latch 550 has a through hole, one end of the pull rod 900 is hooked into the through hole of the latch 550, and the other end of the pull rod 900 is hooked into the actuating rod of the residual current device 300. Thus, when a leakage occurs, the residual current device 300 is actuated, pulling the pull rod 900 through the actuating rod, causing the latch 550 to rotate and unlock, thereby tripping the circuit breaker. (This unlocking and tripping mechanism is a function of the operating mechanism and is common knowledge in the field, so it will not be elaborated here.)

[0072] The middle portion between the first and second ends of the pull rod 900 has a partial bend, forming a drive section 900a, which is located precisely on the deformation trajectory of the bimetallic strip 400. Thus, when an overload occurs, the bimetallic strip 400 bends and pulls the drive section 900a, causing the latch 550 to rotate and unlock, thereby tripping the circuit breaker. (This unlocking and tripping mechanism is a function of the operating mechanism and is common knowledge in the field, so it will not be elaborated further here.)

[0073] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0074] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A residual current circuit breaker, comprising a circuit breaker housing, wherein an operating mechanism, a circuit board, and a test button are disposed inside the circuit breaker housing; characterized in that: The operating mechanism includes a contact support that is rotatably disposed with respect to the circuit breaker housing and a moving contact disposed on the contact support. The moving contact includes a closed state that is in contact with the stationary contact and an open state that is completely separated from the stationary contact. The circuit board includes a power supply circuit and a test circuit, and the power supply circuit and the test circuit share a single stationary contact. The test circuit also includes a test spring. One end of the test spring is electrically connected to the circuit board, and the other end is located between the test button and the stationary contact and is normally open with the stationary contact. When the test button is actuated, the test spring and the stationary contact are connected. The power supply circuit also includes a moving contact spring. One end of the moving contact spring is electrically connected to the moving contact, and the other end of the moving contact spring corresponds to the stationary contact piece. The moving contact spring is fixed on the moving contact and / or the contact support and moves synchronously with the contact support. When the moving contact is in the closed state, it contacts the stationary contact piece to realize the connection of the power supply circuit. When the moving contact is in the open state, it is completely separated from the stationary contact piece to realize the disconnection of the power supply circuit.

2. A residual current circuit breaker according to claim 1, characterized in that: The test button is located on one side of the contact support; the test spring is a torsion spring, which includes a coil, a first extension, and a second extension; the second extension is soldered to the circuit board to achieve electrical connection between the test spring and the circuit board; the first extension is bent toward the test button and abuts against the test button, and the first extension and the stationary contact are normally open, so that the first extension contacts the stationary contact when the test button is activated.

3. A residual current circuit breaker according to claim 2, characterized in that: The circuit breaker housing includes a first chamber and a second chamber, which are arranged sequentially along the length of the circuit breaker housing. The operating mechanism and test button are arranged in the first chamber, and the circuit board is arranged in the second chamber. The circuit breaker housing has a partition protrusion, which is arranged between the first chamber and the second chamber, and a first groove is provided on the partition protrusion. A ring portion and a first extension portion are arranged in the first chamber, and the second extension portion passes through the partition protrusion through the first groove and is welded to the circuit board. The size of the first groove is slightly larger than the diameter of the second extension portion.

4. A residual current circuit breaker according to claim 3, characterized in that: The second extension is formed by continuous bending to form a protrusion. In the width direction of the circuit breaker housing, the protrusion is closer to the opening of the first groove than the welding point between the second extension and the circuit board.

5. A residual current circuit breaker according to claim 3, characterized in that: Along the length of the circuit breaker housing, the first extension and the second extension are on both sides of the ring portion, and the first extension extends as a whole along the width and height directions of the circuit breaker housing.

6. A residual current circuit breaker according to claim 2, characterized in that: The stationary contact piece includes a first contact portion, a connecting portion, a second contact portion, and a welding portion that are bent and connected in sequence; the first contact portion is used to cooperate with the moving contact spring, the second contact portion is used to cooperate with the test spring, and the welding portion is used to weld to the circuit board to form an electrical connection; in the height direction of the circuit breaker housing, the first contact portion is higher than the second contact portion; in the width direction of the circuit breaker housing, the first contact portion and the second contact portion are misaligned.

7. A residual current circuit breaker according to claim 1, characterized in that: One end of the moving contact spring is a fixed end, and the other end is a movable end; the moving contact and the contact support are fixed by riveting, the fixed end is connected to the riveting position, and the movable end is used to cooperate with the stationary contact piece.

8. A residual current circuit breaker according to claim 7, characterized in that: The fixed end is a ring-shaped structure that is fitted onto the riveting position and forms a tight bond during the riveting process.

9. A residual current circuit breaker according to claim 7, characterized in that: The contact support includes a mounting groove, in which the moving contact is located. A portion of the moving contact spring extends along the groove wall and is adjacent to the fixed end.

10. A residual current circuit breaker according to claim 1, characterized in that: The operating mechanism also includes a latch and a pull rod; a residual current device (RCD) and a bimetallic strip are also installed inside the circuit breaker housing; one end of the pull rod is connected to the latch, and the other end is connected to the actuation rod of the RCD; the middle part of the pull rod is bent to form a driving part, which is located on the deformation trajectory of the bimetallic strip; when the RCD is actuated, it drives the pull rod to unlock the latch; when the bimetallic strip bends, it strikes the driving part and drives the pull rod to unlock the latch.

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