Molded case circuit breaker

Abstract

The utility model discloses a molded case circuit breaker. The molded case circuit breaker comprises a base, a middle cover and a top cover, at least one pole of mounting groove is formed in the base, an arc extinguish chamber mounting section is arranged on the mounting groove, and an arc extinguish chamber is arranged in the arc extinguish chamber mounting section; wherein the middle cover is fixed above the base, the middle cover is provided with first air leakage hole groups which are in one-to-one correspondence with the arc extinguish chambers, and the first air leakage hole groups are positioned right above the corresponding arc extinguish chambers; the top cover is fixed above the middle cover, the top cover is provided with buffer spaces in one-to-one correspondence with the first air leakage hole groups and second air leakage hole groups, and the corresponding first air leakage hole groups, buffer spaces and second air leakage hole groups are communicated with one another, so that air from the direction of the arc extinguish chamber is discharged after passing through the first air leakage hole groups, buffer spaces and second air leakage hole groups in sequence; the forming direction of the first air leakage hole set is perpendicular to the forming direction of the second air leakage hole set. The exhaust structure has the characteristic of novel exhaust structure.

Description

TECHNICAL FIELD

[0001] The application relates to the field of low-voltage electrical apparatuses, in particular to a molded case circuit breaker. BACKGROUND

[0002] The high-breakage measuring switch disclosed in CN218274342U is a molded case circuit breaker. In order to ensure that the gas in the circuit breaker can be discharged in time, an arc-extinguishing insulating mesh plate is arranged at the rear part of the base in the arc-extinguishing chamber, and a flexible insulating plate is arranged at the rear part of the arc-extinguishing insulating mesh plate. During breaking, the arc gas passes through the arc-extinguishing chamber, and then blows the flexible insulating plate to bend through the mesh holes of the arc-extinguishing insulating mesh plate, so that the arc gas can be discharged through the mesh holes of the arc-extinguishing insulating mesh plate.

[0003] This exhaust structure has been applied for decades, and how to design a new exhaust structure is undoubtedly a test for those skilled in the art. SUMMARY

[0004] Therefore, the application aims to overcome the deficiencies in the prior art and provides a molded case circuit breaker.

[0005] The application provides a molded case circuit breaker, which comprises a base, a middle cover and a top cover; at least one mounting slot is arranged on the base, the mounting slot is provided with an arc-extinguishing chamber mounting section, and an arc-extinguishing chamber is arranged in the arc-extinguishing chamber mounting section; the middle cover is fixed above the base, the middle cover is provided with a first gas discharge hole group corresponding to the arc-extinguishing chambers one by one, and the first gas discharge hole group is located directly above the corresponding arc-extinguishing chamber; the top cover is fixed above the middle cover, the top cover is provided with a buffer space corresponding to the first gas discharge hole group and a second gas discharge hole group, and the corresponding first gas discharge hole group, buffer space and second gas discharge hole group are in communication with each other, so that the gas from the arc-extinguishing chamber direction is discharged in sequence through the first gas discharge hole group, buffer space and second gas discharge hole group; the first gas discharge hole group is arranged vertically to the second gas discharge hole group.

[0006] In some embodiments of the application, at least two mounting slots are arranged adjacent to each other on the base, and at least two buffer spaces and a partition wall are arranged adjacent to each other on the top cover, and the partition wall separates the two adjacent buffer spaces.

[0007] In some embodiments of the application, the second gas discharge hole group is arranged parallel to the length direction of the mounting slot.

[0008] In some embodiments of the application, the second gas discharge hole group is arranged parallel to the width direction of the mounting slot.

[0009] In some embodiments of the present application, a third group of air release holes is formed on the top cover, and the direction in which the third group of air release holes is formed is perpendicular to the direction in which the second group of air release holes is formed and the direction in which the first group of air release holes is formed.

[0010] In some embodiments of the present application, the number of first air release holes in the first group of air release holes is at least 3, and the number of second air release holes in the second group of air release holes is at least 2; and the number of first air release holes in the corresponding first group of air release holes is more than the number of second air release holes in the second group of air release holes.

[0011] In some embodiments of the present application, the cross-sectional shape of the first air release hole is circular or semicircular or elliptical or semi-elliptical or waist-shaped or half-waist-shaped or polygonal, and the cross-sectional shape of the second air release hole is circular or semicircular or elliptical or semi-elliptical or waist-shaped or half-waist-shaped or polygonal.

[0012] In some embodiments of the present application, a static contact is further arranged in the arc-extinguishing chamber mounting section, and the arc-extinguishing chamber is arranged above the static contact; the arc-extinguishing chamber comprises two side plates and at least two arc-extinguishing grid pieces, and a part of at least one of the arc-extinguishing grid pieces is bent towards the static contact to form an arc striking part.

[0013] In some embodiments of the present application, a static contact and a gas generating cover are further arranged in the arc-extinguishing chamber mounting section; the gas generating cover is of an integrated structure and comprises a static cover part and two side blocking parts; the static contact comprises a wiring section, a connecting section and a contact section, the static cover part completely covers the connecting section, and the contact section is exposed from the static cover part; the arc-extinguishing chamber comprises at least two arc-extinguishing grid pieces, each of which has two grid piece feet, the two side blocking parts correspond to the two grid piece feet respectively, and the side blocking parts extend to the sides of the corresponding grid piece feet.

[0014] In some embodiments of the present application, a first magnetic guide piece is further included, and the first magnetic guide piece is arranged below the contact section.

[0015] In some embodiments of the present application, a second magnetic guide piece is further included, and there are two second magnetic guide pieces respectively, the two side blocking parts have hollow parts inside, and the two second magnetic guide pieces are arranged in the two hollow parts respectively.

[0016] In some embodiments of the present application, an arc-extinguishing chamber cover is further included, and the arc-extinguishing chamber cover is provided with a clearance groove for avoiding the moving contact; the arc-extinguishing chamber further comprises two side plates, and the arc-extinguishing grid pieces are clamped on the two side plates; the arc-extinguishing chamber cover is fixed on the upper end of the arc-extinguishing chamber by being clamped with the side plates.

[0017] The present application has the following beneficial effects compared with the prior art:

[0018] The new exhaust structure is adopted, the gas from the arc extinguishing chamber can be discharged through the first exhaust hole group on the middle cover, the buffer space on the top cover, the second exhaust hole group on the top cover, which is different from the exhaust structure in the prior art, and enriches the exhaust scheme of the molded case circuit breaker. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows, and it should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation to the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0020] Figure 1 An exploded view of the molded case circuit breaker of the embodiment of the present application is shown;

[0021] Figure 2 A schematic view of the air flow exhaust of the molded case circuit breaker of the embodiment of the present application is shown;

[0022] Figure 3 A schematic view of the base in the embodiment of the present application is shown;

[0023] Figure 4 A structural schematic view of the middle cover in the embodiment of the present application is shown;

[0024] Figure 5 A structural schematic view of the top cover in the embodiment of the present application is shown;

[0025] Figure 6 A schematic view of the arc extinguishing chamber, the gas generating cover and the arc extinguishing chamber cover in the embodiment of the present application is shown;

[0026] Figure 7 A partial schematic view of the arc extinguishing chamber and the static contact in the embodiment of the present application is shown;

[0027] Figure 8 A structural schematic view of the gas generating cover and the static contact in the embodiment of the present application is shown;

[0028] Figure 9 A partial sectional view of the gas generating cover and the second magnetic conducting sheet in the embodiment of the present application is shown;

[0029] Figure 10 A schematic view of the arc extinguishing chamber cover and the arc extinguishing chamber in the embodiment of the present application is shown. DETAILED DESCRIPTION

[0030] Embodiments of the present application are described below in the description, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout the drawings. The embodiments described below by referring to the drawings are exemplary only, for the purpose of explaining the present application, and are not to be understood as limiting the present application.

[0031] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and is not to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0032] In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0033] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0034] In the present application, unless otherwise explicitly specified and limited, the first feature "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature. Embodiments

[0035] As Figures 1-10As shown, the embodiment of the present application is a molded case circuit breaker, which comprises a base 100, a middle cover 110 and a top cover 120.

[0036] In the present embodiment, the molded case circuit breaker is of a 3-pole structure, and therefore, the base 100 thereof has three pole mounting slots 101 arranged in sequence in the width direction D.

[0037] The mounting slots 101 here are used for mounting components such as main circuit conductors and arc extinguishing chambers 200. Therefore, the pole mounting slots 101 are divided in sequence (from left to right) in the length direction L according to the different mounting components into a left terminal segment (for placing left wiring terminals), an arc extinguishing chamber mounting segment 1010 (for placing stationary contacts 300 and arc extinguishing chambers 200), a rotating shaft mounting segment (for mounting rotating shafts, and this segment of the middle pole is also used for mounting operating mechanisms), a protection assembly mounting segment (for mounting trip devices, such as thermal-magnetic molded case circuit breakers for mounting thermal-magnetic trip devices, and electronic molded case circuit breakers for mounting transformers, controllers, etc.), and a right terminal segment (for placing right wiring terminals). Figure 3 The middle cover 110 is fixed above the base 100, and the fixing manner between the middle cover 110 and the base 100 here is bolt fastening. Here, the middle cover 110 has a set of first gas venting holes S1 above each arc extinguishing chamber 200, and the first gas venting holes S1 are arranged directly above the corresponding arc extinguishing chamber 200, that is, the gas from the direction of the arc extinguishing chamber 200 can be discharged upward through the first gas venting holes S1.

[0038] The top cover 120 is fixed above the middle cover 110, and the top cover 120 can cover all the first gas venting holes S1. The fixing manner between the top cover 120 and the middle cover 110 here is also bolt fastening.

[0039] Corresponding to each first gas venting hole S1 on the top cover 120, it has a buffer space S2 and a second gas venting hole S3. In the present embodiment, the buffer space S2 here is a groove, so that the corresponding first gas venting hole S1 can communicate with the second gas venting hole S3 through the buffer space S2, so that the gas from the direction of the arc extinguishing chamber 200 is discharged in sequence through the first gas venting hole S1, the buffer space S2 and the second gas venting hole S3.

[0040] Here, the arrangement direction of the first gas venting hole S1 is perpendicular to the arrangement direction of the second gas venting hole S3. That is, if the arrangement direction of the first gas venting hole S1 is the height direction H, then the arrangement direction of the second gas venting hole S3 is a direction perpendicular to the height direction H.

[0041]

[0042] ​The first vent hole group S1, the buffer space S2 and the second vent hole group S3 form a novel exhaust structure, which enriches the choices of the person skilled in the art. Meanwhile, the exhaust mode has good effects in some special cases, for example, when the wiring frame type terminal is used for the circuit breaker, if the traditional exhaust structure is still used, the wiring frame is easy to be directly ablated by the gas, which does not meet the relevant specifications; and the wiring frame is not easy to be ablated by using the exhaust mode, because most of the gas is exhausted from the top cover.

[0043] Taking a single-pole circuit breaker as an example, the first vent hole group S1 is opened in the height direction H, and the second vent hole group S3 can be opened in the length direction L (or parallel to the length direction L, the same below) or in the width direction H (or parallel to the width direction L, the same below).

[0044] Taking a 2-pole circuit breaker as an example, the first vent hole group S1 is opened in the height direction H, and the second vent hole group S3 can be opened in the length direction L or in the width direction H.

[0045] Taking a 2-pole or more circuit breaker as an example, the first vent hole group S1 is opened in the height direction H, the second vent hole group S3 located in the middle (corresponding to the middle installation groove 101) is opened in the length direction L, and the second vent hole group S3 located at both sides (corresponding to the installation groove 101 at both edges) can be opened in the length direction L or in the width direction H.

[0046] For a 2-pole or more circuit breaker, the top cover 120 has a partition wall 121 between every two adjacent buffer spaces S2, the two adjacent buffer spaces S2 are separated by the partition wall 121, so that the mutual gas leakage is prevented, the flow direction of the gas is ensured, and the exhaust effect is improved.

[0047] Similarly, the partition wall 121 can have some arc surfaces formed on the surface, which is more conducive to the flow of the gas and reduces the kinetic energy loss of the gas.

[0048] Of course, the third vent hole group S4 is opened on the top cover 120, and the opening direction of the third vent hole group S4 is perpendicular to the opening direction of the second vent hole group S3 and the opening direction of the first vent hole group S1. Here, according to different pole numbers of the circuit breaker, the number of the third vent hole group S4 is different.

[0049] Taking a single-pole circuit breaker as an example, when the second vent hole group S3 is opened along the length direction L, the third vent hole group S4 is opened along the width direction H.

[0050] Similarly, for the 2-pole circuit breaker, when the second venting hole group S3 is opened along the length direction L, the third venting hole group S4 is opened along the width direction H.

[0051] For the circuit breaker with more than 2 poles, only two third venting hole groups S4 can be opened in the top cover 120, and the two third venting hole groups S4 are respectively corresponding to the two edge mounting grooves 101. In this case, when the second venting hole group S3 is opened along the length direction L, the third venting hole group S4 is opened along the width direction H.

[0052] In any case, when the third venting hole group S4 is opened, the corresponding arc-extinguishing chamber 200 gas can be discharged through the second venting hole group S3 or the third venting hole group S4 after entering the buffer space S2 through the first venting hole group S1, further improving the exhaust effect.

[0053] The first venting hole group S1 is opened in the height direction H, and the second venting hole group S3 can be opened in the length direction L or the width direction H.

[0054] Taking the 2-pole circuit breaker as an example, the first venting hole group S1 is opened in the height direction H, and the second venting hole group S3 can be opened in the length direction L or the width direction H.

[0055] Taking the 3-pole circuit breaker as an example, the first venting hole group S1 is opened in the height direction H, and the second venting hole group S3 corresponding to the middle pole is opened in the length direction L. The second venting hole group S3 corresponding to the two side poles can be opened in the length direction L or the width direction H.

[0056] In any case, the number of the first venting holes 10 in the first venting hole group S1 is more than the number of the second venting holes 30 in the second venting hole group S3. For example, the number of the first venting holes 10 in the first venting hole group S1 is 8, and the number of the second venting holes 30 in the second venting hole group S3 is 4. Of course, the number is not limited to this, as long as the number of the first venting holes 10 in the first venting hole group S1 is at least 3, the number of the second venting holes 30 in the second venting hole group S3 is at least 2, and the number of the first venting holes 10 in the first venting hole group S1 is more than the number of the second venting holes 30 in the second venting hole group S3.

[0057] Such a number requirement will make the exhaust effect better, so that the gas in the arc-extinguishing chamber 200 quickly enters the buffer space S2.

[0058] The cross-sectional shape of the first air vent 10 is selected from a variety of shapes, and in the present embodiment is circular. Of course, other than this, it can also be semicircular, elliptical, semi-elliptical, waist-shaped, semi-waist-shaped, polygonal (a shape formed by three sides or more).

[0059] The cross-sectional shape of the second air vent 30 is selected from a variety of shapes, and in the present embodiment is semi-waist-shaped. Of course, other than this, it can also be circular, semicircular, elliptical, semi-elliptical, waist-shaped, polygonal (a shape formed by three sides or more).

[0060] For the stationary contact 300, it is installed in each arc-extinguishing chamber mounting section 1010, and the stationary contact 300 as a whole is located below the arc-extinguishing chamber 200.

[0061] The arc-extinguishing chamber 200 has two side plates 201 and seven arc-extinguishing vanes 202, all of which are clamped between the two side plates 201. The arc-extinguishing vanes 202 are arranged in order along the movement trajectory of the moving contact, and the lowermost arc-extinguishing vane 202 is partially bent towards the stationary contact 300 to form an arc striking portion 202a, so that the broken arc is more easily introduced into the arc-extinguishing chamber 200. Of course, the arc-extinguishing vanes 202 here are not limited to seven, and can be more or fewer, for example, of course, at least two arc-extinguishing vanes 202 are guaranteed.

[0062] Each stationary contact 300 includes a wiring section 301, a connecting section 302, and a contact section 303, the wiring section 301 extends into the left terminal section, and the connecting section 302 and the contact section 303 are located in the arc-extinguishing chamber mounting section 1010. The contact section 303 here forms a bent connection with the connecting section 302, and the contact section 303 is closer to the arc-extinguishing chamber 200 than the connecting section 302. The gas production cover 400 is installed above the stationary contact 300, and the gas production cover 400 is a one-piece structure including a stationary cover portion 401 and two side blocking portions 402. The stationary cover portion 401 here completely shields the connecting section 302, and only the contact section 303 is exposed from the stationary cover portion 401 (so that the moving contact can contact). The two side blocking portions 402 are arranged in a spaced manner and extend into the arc-extinguishing chamber 200, and the two side blocking portions 402 here correspond to the two vane feet of the arc-extinguishing vanes 202, and the side plates 201 extend to the side of the corresponding vane feet. The structure of the gas production cover 400 can protect the stationary contact 300 through the stationary cover portion 401, prevent the connecting section 302 of the stationary contact 300 from being excessively ablated, and the side blocking portions 402 can also have a certain protective effect on the vane feet to prevent the vane feet from being ablated.

[0063] Below the contact section 303, a first magnetic conductive element 500 is placed. This first magnetic conductive element 500 can generate a magnetic field under the influence of electric induction, which helps to elongate the broken arc and allow it to enter the arc-extinguishing chamber 200. The first magnetic conductive element 500 can be a single piece or formed by riveting together several sheet-like structures.

[0064] Each side baffle 402 has a hollow portion 4020 inside, and a second magnetic conductive sheet 600 is disposed in the hollow portion 4020. The opening of the hollow portion 4020 is formed on the stationary cover portion 401, and the second magnetic conductive sheet 600 can be inserted into the hollow portion 4020 through the opening. In this way, the second magnetic conductive sheet 600 will be closer to the arc extinguishing grid 202. During the breaking process, the arc will be further elongated by the magnetic force of the second magnetic conductive sheet 600, which is more conducive to arc extinguishing.

[0065] An arc-extinguishing chamber cover 700 is fixed to each arc-extinguishing chamber 200. The function of the arc-extinguishing chamber cover 700 is to allow the arc to be extinguished more concentratedly within the arc-extinguishing chamber 200. The arc-extinguishing chamber cover 700 is provided with a relief groove 701 to prevent interference with the moving contact. The specific shape of the arc-extinguishing chamber cover 700 is to fit the upper end shape of the arc-extinguishing chamber 200, specifically the upper end shape of the side plate 201. The arc-extinguishing chamber cover 700 has a retaining groove 702, and the side plate 201 has a protrusion that can be inserted into the retaining groove 702 to form a snap-fit ​​fixation.

[0066] The height direction H, length direction L, and width direction H mentioned above refer to the height direction H, length direction L, and width direction H of the mounting groove 101. Of course, they can also be understood as the height direction H, length direction L, and width direction H of the circuit breaker, which are essentially the same.

[0067] 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.

[0068] 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 molded case circuit breaker, comprising a base, a middle cover and a top cover; at least one pole mounting slot is arranged on the base, the mounting slot is provided with an arc-extinguishing chamber mounting section, and an arc-extinguishing chamber is arranged in the arc-extinguishing chamber mounting section; characterized in that: The middle cover is fixed above the base, and the middle cover is provided with a first gas vent group corresponding to the arc-extinguishing chamber one by one, and the first gas vent group is located directly above the corresponding arc-extinguishing chamber. The top cover is fixed above the middle cover, and the top cover is provided with a buffer space corresponding to the first gas vent group one by one and a second gas vent group, and the corresponding first gas vent group, buffer space and second gas vent group are communicated with each other, so that the gas from the arc-extinguishing chamber direction is discharged in sequence through the first gas vent group, buffer space and second gas vent group; the opening direction of the first gas vent group is perpendicular to the opening direction of the second gas vent group.

2. A molded case circuit breaker according to claim 1, wherein: The base is provided with at least two installation grooves arranged adjacent to each other, and the top cover is provided with at least two buffer spaces arranged adjacent to each other and a partition wall, and the partition wall separates the two buffer spaces arranged adjacent to each other.

3. A molded case circuit breaker according to claim 1 or 2, characterized in that: The opening direction of the second gas vent group is parallel to the length direction of the installation groove; or the opening direction of the second gas vent group is parallel to the width direction of the installation groove.

4. A molded case circuit breaker according to claim 1 or 2, wherein: The top cover is provided with a third gas vent group, and the opening direction of the third gas vent group is perpendicular to the opening direction of the second gas vent group and the opening direction of the first gas vent group.

5. A molded case circuit breaker according to claim 1, wherein: The number of the first gas vents in the first gas vent group is at least three, and the number of the second gas vents in the second gas vent group is at least two; the number of the first gas vents in the corresponding first gas vent group is more than the number of the second gas vents in the second gas vent group.

6. A molded case circuit breaker according to claim 5 wherein: The cross-sectional shape of the first gas vent is circular or semicircular or elliptical or semi-elliptical or waist-shaped or half-waist-shaped or polygonal, and the cross-sectional shape of the second gas vent is circular or semicircular or elliptical or semi-elliptical or waist-shaped or half-waist-shaped or polygonal.

7. A molded case circuit breaker according to claim 1, wherein: The static contact is further arranged in the arc-extinguishing chamber mounting section, and the arc-extinguishing chamber is arranged above the static contact; the arc-extinguishing chamber comprises two side plates and at least two arc-extinguishing grid plates, and a part of at least one arc-extinguishing grid plate is bent towards the static contact to form an arc striking part.

8. The molded case circuit breaker of claim 1, wherein: The static contact and the gas generation cover are further arranged in the arc-extinguishing chamber mounting section; The gas generation cover is of an integrated structure, comprising a static cover part and two side blocking parts; the static contact comprises a wiring section, a connecting section and a contact section, the static cover part completely covers the connecting section, and the contact section is exposed from the static cover part; the arc-extinguishing chamber comprises at least two arc-extinguishing grid plates, each arc-extinguishing grid plate has two grid plate feet, the two side blocking parts correspond to the two grid plate feet respectively, and the side blocking parts extend to the sides of the corresponding grid plate feet.

9. A molded case circuit breaker according to claim 8 wherein: Further comprising a first magnetic guide, which is arranged below the contact section; and / or further comprising two second magnetic guides, the two side blocking parts have hollow parts inside, and the two second magnetic guides are arranged in the two hollow parts respectively.

10. The molded case circuit breaker of claim 8, wherein: Further comprising an arc-extinguishing chamber cover, which is provided with a avoiding slot for avoiding the moving contact; the arc-extinguishing chamber further comprises two side plates, and the arc-extinguishing chamber cover is fixed at the upper end of the arc-extinguishing chamber by clamping the side plates.

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