Miniature circuit breaker

Abstract

The utility model relates to a small circuit breaker, including base, middle lid, upper cover and operating mechanism, operating mechanism and middle lid set up between upper cover and base, the middle lid top forms a gap, operating mechanism sets up in the gap of middle lid top, the middle lid and base form N pole cavity, the middle lid and upper cover form L pole cavity, the middle lid includes integrative terminal portion, arc extinguishing part, thermal protection part, both sides of terminal portion all are provided with binding post, both sides of arc extinguishing part all are provided with arc extinguishing cover and static contact, thermal protection part sets up bimetallic strip in L pole cavity, both sides of terminal portion and arc extinguishing part are mutually symmetrical, thermal protection part sets up in the one side of N pole cavity deflection, operating mechanism is provided with arc baffle, and the arc baffle extends to the L pole cavity side of thermal protection part, the middle lid adopts asymmetric design in thermal protection part, makes the space of L pole cavity greater than the space of N pole cavity, and it is convenient for installing bimetallic strip and so on thermal protection element in L pole.

Description

Technical Field

[0001] This utility model relates to a miniature circuit breaker. Background Technology

[0002] A 1P+N miniature circuit breaker is a small circuit breaker that uses a single operating mechanism to simultaneously control the opening and closing of both the L and N poles. Existing 1P+N miniature circuit breakers typically consist of one L pole circuit breaker and one N pole circuit breaker. Their width is generally two modules (i.e., 36mm), making them relatively large and requiring a significant amount of installation space. Summary of the Invention

[0003] To address the aforementioned shortcomings, this utility model provides a miniature circuit breaker that integrates the L and N poles within an 18mm housing.

[0004] To achieve the above objectives, this utility model employs a miniature circuit breaker, comprising a base, a middle cover, a top cover, and an operating mechanism. The operating mechanism and the middle cover are disposed between the top cover and the base. A notch is formed above the middle cover, and the operating mechanism is disposed within the notch above the middle cover. An N-pole cavity is formed between the middle cover and the base, and an L-pole cavity is formed between the middle cover and the top cover. The middle cover includes an integrally formed terminal portion, an arc-extinguishing portion, and a thermal protection portion. Wiring terminals are provided on both sides of the terminal portion. Arc-extinguishing covers and stationary contacts are provided on both sides of the arc-extinguishing portion. A bimetallic strip is disposed within the L-pole cavity of the thermal protection portion. The two sides of the terminal portion and the arc-extinguishing portion are symmetrical to each other. The thermal protection portion is disposed on the side biased towards the N-pole cavity. An arc-blocking plate is disposed on the operating mechanism, extending to one side of the thermal protection portion. The arc-blocking plate overlaps with the thermal protection portion on the L-pole cavity side.

[0005] The beneficial effect of this utility model is that the middle cover adopts an asymmetrical design in the thermal protection section, making the space of the L pole cavity larger than that of the N pole cavity. This facilitates the installation of thermal protection elements such as bimetallic strips on the L pole. At the same time, the rest of the parts remain symmetrical, allowing for assembly using identical components and saving mold costs. During the opening moment, the moving and stationary contacts of the circuit breaker generate a large amount of electric arc and high-temperature gas. This high-temperature gas impacts the surrounding area. Because the operating mechanism of the circuit breaker needs to allow for rotational space, this area cannot be shielded, causing some of the arc gas to impact the operating mechanism, resulting in a short circuit and breakdown between the L and N poles. An arc-blocking plate is added to the bracket, allowing the moving contact to rotate during opening and closing, directly overlapping with the arc-blocking plate to achieve connection shielding during the opening and closing process of the moving contact, ensuring the shielding effect against the arc gas.

[0006] Specifically, the operating mechanism of this utility model includes a handle, a connecting rod, a latch, a contact bracket, and a moving contact. The latch is hinged to the contact bracket, and a latch position is formed at the upper end of the contact bracket. A latch groove is formed on the latch, and the latch groove is bent upward at the corresponding latch position to form a jump latch part. One end of the connecting rod is inserted into the latch groove, and the other end of the connecting rod is connected to the handle. There are two moving contacts, which are connected to the lower end of the contact bracket. The lower end of the moving contact extends to both sides of the arc-extinguishing part of the middle cover. An arc-blocking plate is set on the lower side of the contact bracket and between the two moving contacts.

[0007] In the above technical solution, the operating mechanism does not have a jump lock, but is directly connected to the lock by a connecting rod, which facilitates the assembly of the operating mechanism.

[0008] Specifically, the latch of this invention features a bimetallic pull rod integrally formed at one end near the bimetallic strip, with the outer end of the pull rod positioned on the outer side of the bimetallic strip. The position of the bimetallic pull rod does not need to bypass the moving contact, thus reducing the width of the operating mechanism.

[0009] In particular, the arc-extinguishing part of the middle cover of this utility model is provided with an arc-venting channel, which is connected to the rear of the arc-extinguishing cover.

[0010] Specifically, the wiring terminals inside the L-pole cavity of this invention are positioned higher than the wiring terminals inside the N-pole cavity. This different height design facilitates the identification of the L and N poles and makes installation easier.

[0011] In particular, the arc-extinguishing part of this utility model has arc-inducing plates on both sides in front of the arc-extinguishing cover, a lower arc-inducing plate is provided below the moving contact, the lower arc-inducing plate extends to the bottom of the arc-extinguishing cover, and an upper arc-inducing plate is connected to the stationary contact, the upper arc-inducing plate extends to the top of the arc-extinguishing cover.

[0012] The arc-inducing plates and upper and lower arc-inducing plates on both sides of the arc-extinguishing chamber form an arc channel, which enhances the electromagnetic induction intensity and increases the electrodynamic force of the arc, allowing the arc to enter the arc-extinguishing chamber quickly. The arc-dissipating channel and air outlet at the rear end of the arc-extinguishing chamber prevent the airflow from affecting each other inside the arc-extinguishing chamber, effectively reducing the residence time of the arc inside the circuit breaker. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a specific embodiment of the present utility model.

[0014] Figure 2 This is an exploded view of a specific embodiment of this utility model.

[0015] Figure 3 This is a cross-sectional view of a specific embodiment of the present utility model.

[0016] Figure 4 This is a front view of a specific embodiment of the present invention without the top cover and base.

[0017] Figure 5 This is a schematic diagram of the middle cover in a specific embodiment of this utility model.

[0018] Figure 6 This is a front view of the operating mechanism in a specific embodiment of this utility model.

[0019] Figure 7 This is a schematic diagram of the operating mechanism in a specific embodiment of this utility model. Detailed Implementation

[0020] like Figures 1 to 7 As shown, a specific embodiment of this utility model is a miniature circuit breaker, including a base 4, a middle cover 1, an upper cover 3, and an operating mechanism 2. The operating mechanism 2 and the middle cover 1 are disposed between the upper cover 3 and the base 4. A notch 10 is formed above the middle cover 1, and the operating mechanism 2 is disposed in the notch 10 above the middle cover 1. An N-pole cavity 41 is formed between the middle cover 1 and the base 4, and an L-pole cavity 31 is formed between the middle cover 1 and the upper cover 3. The middle cover 1 includes an integrally formed terminal part 11, an arc-extinguishing part 12, and a thermal protection part 13. Wiring terminals 5 are provided on both sides of the terminal part 11. The wiring terminals 5 in the L-pole cavity 31 are positioned higher than the wiring terminals 5 in the N-pole cavity 41. An arc-extinguishing cover 6 and a stationary contact 7 are provided on both sides of the arc-extinguishing part 12. A bimetallic strip 8 is provided in the L-pole cavity 31. The two sides of the terminal part 11 and the arc-extinguishing part 12 are symmetrical to each other. The thermal protection part 13 is disposed on the side biased towards the N-pole cavity 41, so that the space of the L-pole cavity 31 is larger than the space of the N-pole cavity 41.

[0021] The operating mechanism 2 includes a handle 21, a connecting rod 22, a latch 23, a contact bracket 24, and a moving contact 25. The latch 23 is hinged to the contact bracket 24. A latch position 241 is formed at the upper end of the contact bracket 24. A latch groove 231 is formed on the latch 23. The latch groove 231 is bent upward at the corresponding latch position 241 to form a jump latch. One end of the connecting rod 22 is inserted into the latch groove 231, and the other end of the connecting rod 22 is connected to the handle 21. There are two moving contacts 25. The moving contacts 25 are connected to both sides of the lower end of the contact bracket 24. The lower end of the moving contacts 25 extends to both sides of the arc extinguishing part 12 of the middle cover 1. An arc baffle 26 is provided on the lower side of the contact bracket 24. The arc baffle 26 is located between the two moving contacts 25. The arc baffle 26 extends towards the middle cover 1. The front end of the arc baffle 26 extends to one side of the L pole cavity 31 of the thermal protection part 13. The arc baffle 26 overlaps with the thermal protection part 13.

[0022] A double metal pull rod 232 is integrally formed on the latch 23 near the end of the bimetallic strip 8, and the outer end of the double metal pull rod 232 is located on the outer side of the bimetallic strip 8.

[0023] An arc-extinguishing channel 14 is provided inside the arc-extinguishing part 12 of the middle cover 1. The arc-extinguishing channel 14 is connected to the rear part of the arc-extinguishing cover 6, and an air outlet is provided at the end of the arc-extinguishing channel 14.

[0024] Arc-extinguishing section 12 has arc-initiating plates 9 on both sides in front of arc-extinguishing cover 6. A lower arc-initiating plate 251 is located below the moving contact 25, extending to the bottom of arc-extinguishing cover 6. An upper arc-initiating plate 71 is connected to the stationary contact 7, extending to the top of arc-extinguishing cover 6. The arc-initiating plates 9 and the upper and lower arc-initiating plates (71, 251) on both sides of arc-extinguishing cover 6 form an arc channel, enhancing electromagnetic induction intensity and increasing the electrodynamic force of the arc, allowing the arc to quickly enter arc-extinguishing cover 6. The arc-dissipating channel 14 and air outlet at the rear end of arc-extinguishing cover 6 prevent airflow from interfering with each other within arc-extinguishing cover 6, effectively reducing the residence time of the arc inside the circuit breaker.

[0025] The preferred embodiments of the present invention described above, as well as other obvious variations, are also within the scope of protection of the claims.

Claims

1. A miniature circuit breaker, comprising a base, a middle cover, a top cover, and an operating mechanism, wherein the operating mechanism and the middle cover are disposed between the top cover and the base, a notch is formed above the middle cover, the operating mechanism is disposed within the notch above the middle cover, an N-pole cavity is formed between the middle cover and the base, and an L-pole cavity is formed between the middle cover and the top cover, the middle cover comprising an integrally formed terminal portion, an arc-extinguishing portion, and a thermal protection portion, wherein wiring terminals are provided on both sides of the terminal portion, an arc-extinguishing cover and a stationary contact are provided on both sides of the arc-extinguishing portion, and a bimetallic strip is disposed within the L-pole cavity of the thermal protection portion, characterized in that: The terminal portion and the arc-extinguishing portion are symmetrical on both sides. The thermal protection portion is located on the side biased towards the N-pole cavity. The operating mechanism is provided with an arc-blocking plate that extends to one side of the thermal protection portion. The arc-blocking plate overlaps with the thermal protection portion on the L-pole cavity side.

2. The miniature circuit breaker according to claim 1, characterized in that: The operating mechanism includes a handle, a connecting rod, a latch, a contact bracket, and moving contacts. The latch is hinged to the contact bracket, and a latch position is formed at the upper end of the contact bracket. A latch groove is formed on the latch, and the latch groove bends upward at the corresponding latch position to form a snap-lock part. One end of the connecting rod is inserted into the latch groove, and the other end of the connecting rod is connected to the handle. There are two moving contacts, which are connected to the lower end of the contact bracket. The lower end of the moving contacts extends to both sides of the arc-extinguishing part of the middle cover. An arc-blocking plate is disposed on the lower side of the contact bracket and between the two moving contacts.

3. The miniature circuit breaker according to claim 2, characterized in that: The latch has a double metal pull rod integrally formed on one end near the bimetallic strip, and the outer end of the double metal pull rod is located on the outside of the bimetallic strip.

4. The miniature circuit breaker according to claim 2 or 3, characterized in that: An arc-venting channel is provided inside the arc-extinguishing part of the middle cover, and the arc-venting channel is connected to the rear of the arc-extinguishing cover.

5. The miniature circuit breaker according to claim 1, 2, or 3, characterized in that: The terminal block in the L-pole cavity is positioned higher than the terminal block in the N-pole cavity.

6. The miniature circuit breaker according to claim 4, characterized in that: Arc-extinguishing section has arc-inducing plates on both sides in front of the arc-extinguishing cover. A lower arc-inducing plate is provided below the moving contact, extending to the bottom of the arc-extinguishing cover. An upper arc-inducing plate is connected to the stationary contact, extending to the top of the arc-extinguishing cover.

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