CN216624083U

CN216624083U - Isolating switch

Info

Publication number: CN216624083U
Application number: CN202122517468.6U
Authority: CN
Inventors: 司莺歌; 朱俊
Original assignee: Zhejiang Chint Electrics Co Ltd
Current assignee: Zhejiang Chint Electrics Co Ltd
Priority date: 2021-10-19
Filing date: 2021-10-19
Publication date: 2022-05-27
Anticipated expiration: 2031-10-19

Abstract

The utility model provides an isolating switch, including the shell and set up moving contact subassembly and static contact subassembly in the shell be equipped with the isolation chamber with outside intercommunication in the shell the lateral wall of isolating the chamber is equipped with the arc chute piece, the moving contact subassembly of rotation assembly in isolating the intracavity includes link and moving contact, the first end of link forms the upset with the shell normal running fit and is connected, the internal one side of link is connected with the moving contact and around the moving contact protrusion be equipped with arc chute piece complex arc baffle, at the combined floodgate in-process, the link lid closes the isolation chamber and makes moving contact and static contact subassembly cooperation, at the separating brake in-process, the link outwards overturns and makes moving contact and static contact subassembly separation, after the moving contact gets into the isolation chamber, extinguish electric arc by arc baffle and arc chute piece cooperation separation. In the process of opening the brake, the moving contact enters the isolation cavity, and the electric arc is extinguished under the common cooperation of the arc baffle and the arc extinguishing grid plate, so that the current with the load is favorably cut off.

Description

Isolating switch

Technical Field

The utility model relates to the field of switches, in particular to an isolating switch.

Background

An isolating switch is an important switching device and is mainly used for isolating a power supply and connecting and disconnecting a low-current circuit. Because isolator does not have special arc extinguishing device, can't realize taking the load operation, consequently, when operating isolator, must make the circuit breaker of rear end break off the load earlier, just then can break off isolator and carry out isolation protection, like this, can not take the load operation to reduce isolator's application convenience, influence the application and popularization in market.

Disclosure of Invention

The utility model aims to overcome the defects of the prior art and provides a disconnecting switch with an arc extinguishing device.

In order to realize the purpose, the utility model adopts the following technical scheme:

the utility model provides an isolating switch, includes the shell and sets up the contact mechanism in the shell, contact mechanism includes movable contact subassembly and the static contact subassembly of mutually supporting be equipped with the isolation chamber with outside intercommunication in the shell the lateral wall of isolating the chamber is equipped with the arc chute piece, and the moving contact subassembly of rotating assembly in isolating the intracavity includes linkage and moving contact, and the first end and the shell normal running fit of linkage form the upset and be connected, and the internal one side of linkage is connected with the moving contact and is equipped with around the moving contact protrusion with arc chute piece complex arc baffle, and at the combined floodgate in-process, the linkage lid closes the isolation chamber and makes movable contact and static contact subassembly cooperation, and at the separating brake in-process, the linkage outwards overturns and makes movable contact and static contact subassembly separation.

Furthermore, one side of the isolation cavity is provided with at least one connecting shaft, the first end of the linkage piece is rotatably connected with the connecting shaft, the other side of the isolation cavity is provided with two groups of arc-extinguishing grid pieces, each group of arc-extinguishing grid pieces are opposite to the positive side and the negative side of the second end of the linkage piece respectively, and the moving contact enters the isolation cavity and is positioned between the two groups of arc-extinguishing grid pieces.

Furthermore, two arc blocking plates are arranged at the edge of the second end of the linkage part, the two arc blocking plates are respectively arranged on the front side and the back side of the linkage part in a protruding mode, and the second end of the movable contact is located between the two arc blocking plates.

And furthermore, a pull ring is arranged on one outer side of the linkage part, and the moving contact assembly is driven by the pull ring to turn outwards to perform brake opening.

Furthermore, one side of the shell is provided with a limiting part, the limiting part is provided with a clamping groove, and the clamping groove is matched with the pull ring to enable the movable contact assembly to be kept at the opening position.

Furthermore, the shell is provided with a window opposite to the moving contact component, the window is sealed by a visual clapboard, and the opening and closing conditions of the moving contact component can be observed through the visual clapboard.

Furthermore, the window is positioned on the side wall of the isolation cavity, and a limit groove for limiting and installing the visual partition plate is arranged on the inner side wall of the isolation cavity adjacent to the window.

Further, the both ends of shell are equipped with first binding post and second binding post respectively, the static contact subassembly includes stationary contact and clamp, the one end and the second binding post of stationary contact are connected, and the other end of stationary contact extends to the direction that deviates from second binding post, the clamp is connected in the one end that the stationary contact deviates from second binding post, and the opening of clamp is kept apart the chamber and is supplied the moving contact to peg graft towards.

Further, the linkage piece includes integrated into one piece's apron and connecting portion, the external one side of one side face as the linkage piece of apron is equipped with the connection boss be provided with the pull ring on the connection boss, the opposite side face of apron is connected with one side of connecting portion, and the opposite side of connecting portion is equipped with the holding tank as internal one side the moving contact is assembled in the holding tank the first end of connecting portion is equipped with a pair of rotating part, and a pair of rotating part is protruding respectively and is set up the positive and negative both sides of connecting portion and be used for with shell normal running fit, is equipped with a pair of arc board at the second end of connecting portion, and a pair of arc board sets up along the positive and negative both sides edge protrusion of connecting portion second end respectively, and the one end and the apron of every arc board link up, and the other end extends to the both sides of moving contact to the direction that is close to connecting portion second end.

Furthermore, a first terminal groove and a second terminal groove are respectively arranged at two ends of the shell, the shell between the first terminal groove and the second terminal groove protrudes outwards to form a convex part, so that the whole shell is in a convex shape with two lower ends and a higher middle part, the side wall of one side of the convex part is opened, two groups of arc-extinguishing grid sheets are arranged at one side of the convex part close to the second terminal groove to form an isolation cavity in the convex part, the two groups of arc-extinguishing grid sheets are respectively arranged on the side walls of the two opposite isolation cavities, two connecting shafts which are in running fit with the linkage part are arranged at one side of the isolation cavity close to the first terminal groove, a window is arranged at the side wall of the isolation cavity far away from the first terminal groove, the window is covered by a visual clapboard, a limiting groove for limiting the visual clapboard is arranged at one side of each group of arc-extinguishing grid sheets close to the window, a mounting groove for assembling a static contact component is arranged at the middle part of the shell close to the second terminal groove, the mounting groove is opposite to one side of the isolation cavity, which is provided with the arc extinguishing grid piece, the side wall of one side, which is close to the first terminal groove, of the isolation cavity protrudes outwards to form a limiting part, and a clamping groove is formed in the limiting part towards one side of the first terminal groove.

According to the isolating switch, the arc extinguishing grid pieces are arranged on the side wall of the isolating cavity, the arc baffle plates are arranged on the assembly, and the moving contact enters the isolating cavity in the opening process, so that electric arcs are blocked and extinguished through the cooperation of the arc baffle plates and the arc extinguishing grid pieces, the isolating switch is favorable for cutting off current with loads, and the operation convenience of the isolating switch is improved.

In addition, the shell is provided with the window and is covered by the visible partition plate, so that whether the moving contact assembly is in a switching-on/off state or not can be observed from the outside, and the operation safety and convenience of the isolating switch are improved.

In addition, the outer part of the shell is provided with a limiting part, and the movable contact assembly in turnover motion can be kept at a brake separating position through the matching of the pull ring and the clamping groove of the limiting part.

Drawings

FIG. 1 is a schematic structural diagram of an isolating switch in a closing state according to the present invention;

FIG. 2 is a schematic structural diagram of an isolating switch according to the present invention in an open state;

fig. 3 is a schematic structural diagram of a moving contact assembly in the isolating switch of the utility model;

figure 4 is a schematic view of the linkage of the disconnector of the utility model;

FIG. 5 is a schematic structural diagram of an upper cover of a disconnecting switch according to the present invention;

fig. 6 is a schematic structural view of a base in the disconnecting switch of the present invention;

fig. 7 is a schematic structural view of a visual partition in the disconnecting switch of the present invention.

Detailed Description

The following describes a specific embodiment of a disconnector according to the present invention with reference to the embodiments shown in fig. 1 to 7. A disconnector of the utility model is not limited to the description of the following embodiments.

An isolating switch comprises a shell and a contact mechanism arranged in the shell, wherein the contact mechanism comprises a movable contact component and a fixed contact component which are mutually matched, an isolation cavity communicated with the outside is arranged in the shell, arc extinguishing grid sheets 14 are arranged on the side walls of the isolation cavity, a moving contact component rotatably assembled in the isolation cavity comprises a linkage part 21 and a moving contact 22, the first end of the linkage part 21 is rotatably matched with the shell to form turnover connection, one inner side of the linkage part 21 is connected with the moving contact 22 and is convexly provided with an arc baffle plate 215 matched with the arc extinguishing grid sheets 14 around the moving contact 22, in the closing process, the linkage piece 21 covers the isolation cavity to enable the movable contact 22 to be matched with the static contact component, during the switching-off process, the linkage piece 21 is turned outwards to separate the moving contact 22 from the static contact component, after the movable contact 22 enters the isolated cavity, the arc-extinguishing barrier 215 cooperates with the arc-extinguishing grid 14 to block the extinguished arc.

According to the isolating switch, the arc extinguishing grid piece 14 is arranged on the side wall of the isolating cavity, the arc baffle plate 215 is arranged on the movable contact assembly, and in the opening process, the movable contact 22 enters the isolating cavity, so that electric arcs are blocked and extinguished through the cooperation of the arc baffle plate 215 and the arc extinguishing grid piece 14, the isolating switch is favorable for cutting off current with loads, and the operation convenience of the isolating switch is improved.

An embodiment of a disconnecting switch is provided with reference to fig. 1 to 7, where the disconnecting switch includes a housing, a first connection terminal 51 and a second connection terminal 52 are respectively disposed at two ends of the housing, a contact mechanism is disposed between the first connection terminal 51 and the second connection terminal 52, the contact mechanism includes a stationary contact component and a movable contact component that are matched with each other, the stationary contact component is electrically connected to the second connection terminal 52, preferably, a mounting groove is disposed on a side wall of the housing near the second connection terminal 52, the stationary contact component is mounted in the mounting groove, and the movable contact component is electrically connected to the first connection terminal 51 through a conducting wire 53.

The isolating switch is a pull ring type isolating switch, a communicating cavity communicated with the outside is arranged in the shell, the static contact component is opposite to the communicating cavity, a pull ring 4 is arranged on one side of the moving contact component, one end of the moving contact component is in turning connection through being matched with the shell in a rotating mode, when the isolating switch is switched on, the moving contact component covers the communicating cavity and penetrates through the communicating cavity to be matched with the static contact component, and the moving contact component covering the communicating cavity is turned outwards to be separated from the static contact component to achieve switching-off through operation of the pull ring 4.

In this embodiment, at least one set of arc extinguishing grids is disposed on the side wall of the communicating cavity, so that the communicating cavity forms an isolation cavity, and the arc blocking plate 215 disposed on the movable contact assembly cooperates with the arc extinguishing grids 14 to block an arc generated when the contact extinguishing mechanism is disconnected. The moving contact component comprises a linkage part 21 and a moving contact 22, the first end of the linkage part 21 is in turning connection with the shell in a rotating fit manner, a pull ring 4 is arranged on one outward side of the linkage part 21, one inward side of the linkage part 21 is connected with the moving contact 22, an arc baffle 215 is convexly arranged around the moving contact 22, the arc baffle 215 corresponds to the arc extinguishing grid 14, the moving contact 22 is driven by the linkage 21 to perform the opening and closing action, in the switching-on process, the linkage piece 21 covers the isolation cavity, so that the movable contact 22 passes through the isolation cavity to be matched with the static contact component, during the switching-off process, the movable contact assembly is turned outwards to separate the movable contact 22 from the fixed contact assembly, after the moving contact 22 enters the isolated cavity, the arc barrier 215 cooperates with the arc extinguishing grid 14 to block and extinguish the arc, wherein the arc baffle 215 prevents the arc from being ejected from the isolated chamber, and the arc is elongated by the arc chute 14 when isolated to accelerate the extinguishing of the arc. Preferably, a limiting part 15 is arranged outside the housing, a clamping groove 151 is arranged on the limiting part 15, and the movable contact assembly can be kept in the opening state through the matching of the clamping groove 151 and the pull ring 4.

Further, at least one connecting shaft 13 and at least two groups of arc extinguishing bars 14 are further arranged in the isolation cavity, the connecting shaft 13 and the arc extinguishing bars 14 respectively correspond to two ends of the moving contact component, wherein the connecting shaft 13 is rotatably connected with a first end of a linkage member 21, so that the linkage member 21 drives the moving contact 22 to perform switching on and off rotation, and the connecting shaft 13 can be only arranged on one side wall of the isolation cavity or can be symmetrically arranged on two opposite side walls of the isolation cavity. At least two sets of arc extinguishing bars 14 are arranged on one side of the isolation cavity, each set of arc extinguishing bars 14 comprises a plurality of arc extinguishing bars 14 arranged at intervals, fig. 5 and 6 show that each set of arc extinguishing bars 14 is arranged along the action direction perpendicular to the movable contact 22, namely, the arc extinguishing bars are transversely arranged in the drawing, wherein at least one set of arc extinguishing bars 14 are respectively arranged on the side wall of the isolation cavity opposite to the front side and the back side of the second end of the linkage 21, so that the movable contact 22 is at least positioned between the two sets of arc extinguishing bars 14 after entering the isolation cavity, and the side wall of the isolation cavity opposite to the second end of the linkage 21 can be provided with no arc extinguishing bars 14 or provided with one or more sets of arc extinguishing bars 14. Of course, the arc extinguishing effect can also be realized by arranging one or more groups of arc extinguishing grid pieces 14 on the side wall of each side of the isolation cavity, but the structure easily causes the volume of the isolation cavity to be too large, and the cost is higher.

Further, two arc baffles 215 are arranged at the edge of the second end of the linkage member 21, the two arc baffles 215 are convexly arranged on the front side and the back side of the linkage member 21, so that the second end of the movable contact 22 is positioned between the two arc baffles 215 to prevent the arc from being sprayed out.

Furthermore, the shell is provided with a window, preferably the window is positioned on the side wall of the shell opposite to the movable contact component, the window is closed by a visual clapboard 16, wherein the visual clapboard 16 is made of transparent materials, so that the opening and closing states of the movable contact component can be observed through the visual clapboard 16. The fixing mode of the visual clapboard 16 and the shell can adopt screw fixation, bonding or splicing fit.

The specific structure of this embodiment is provided by combining fig. 1-7, a first terminal groove and a second terminal groove are respectively provided at two ends of the housing, a protruding portion is formed by the housing between the first terminal groove and the second terminal groove protruding outward, so that the housing is in a "convex" shape with two lower ends and a higher middle part as a whole, a side wall of one side of the protruding portion is opened as a whole, two sets of opposite arc-extinguishing grid plates 14 are provided at one side of the protruding portion close to the second terminal groove, thereby an isolated cavity is formed inside the protruding portion, two connecting shafts 13 are provided at one side of the isolated cavity close to the first terminal groove, a window is provided at the side wall of the isolated cavity far away from the first terminal groove, i.e. the window is provided on the side wall of the isolated cavity close to the two sets of arc-extinguishing grid plates, the window is covered by a visible partition plate 16, a limiting groove 17 for limiting the visible partition plate 16 is provided at one side of each set of arc-extinguishing grid plate 14 close to the window, as shown in fig. 1, 2 and 7, the visual separating plate 16 of the present embodiment is in an insertion fit with the housing, the visual separating plate 16 is a rectangular plate-shaped structure, and the two side edges of the visual separating plate 16 are thinner to form insertion portions 161 for insertion fit with the limiting grooves 17. Be equipped with the mounting groove that is used for assembling the stationary contact subassembly in the middle part of the shell that is close to the second terminal groove, the mounting groove is relative with one side that the isolation chamber is equipped with arc extinguishing bars piece 14, is close to a lateral wall outside protrusion in first terminal groove by the isolation chamber and forms spacing portion 15 is equipped with draw-in groove 151 towards one side in first terminal groove.

As shown in fig. 5 and 6, the housing includes an upper cover 11 and a base 12 which are covered with each other, a first groove is formed at one end of each of the upper cover 11 and the base 12, a first terminal groove is formed by splicing the two first grooves, a second groove is formed at the other end of each of the upper cover 11 and the base 12, a second terminal groove is formed by splicing the two second grooves, a protruding portion is formed by protruding the upper cover 11 and the base 12 between the first groove and the second groove to the same side, which protrudes upward in the figure, and opens the upper side of the protruding portion as a whole, a window is provided on the left sidewall of the protruding portion, a limit groove 17 is provided on the inner sidewalls of the upper cover 11 and the base 12 adjacent to the window, a set of arc extinguishing grids 14 are provided on the inner sidewalls of the upper cover 11 and the base 12 near the limit groove 17, thereby forming an isolation chamber inside of the protruding portion, a pair of connecting shafts 13 is provided on the side of the protruding portion far from the window, two connecting shafts 13 are oppositely arranged on the inner side walls of the upper cover 11 and the base 12.

As shown in fig. 1 to 4, the movable contact assembly includes a moving contact 22 and a moving contact 21, the moving contact 21 includes a cover 211 and a connecting portion 212, the cover 211 is preferably sized to match the open side of the isolation cavity, a plate surface of one side of the cover 211 is provided with a connecting boss 216 as an outer side of the moving contact 21, the connecting boss 216 is located at a second end of the moving contact 21, a pull ring 4 is provided on the connecting boss 216, a plate surface of the other side of the cover 211 is connected to one side of the connecting portion 212, another side of the connecting portion 212 is provided with an accommodating slot 213 as an inner side, in fig. 3 and 4, two open ends of the accommodating slot 213 are provided, the moving contact 22 is assembled in the accommodating slot 213, the moving contact 22 is in a plate-shaped structure as a whole in fig. 1 to 3, the moving contact 22 is riveted and fixed in the accommodating slot 213, wherein a first end of the moving contact 22 passes through an opening of the accommodating slot 213 and is connected to the first connection terminal 51 through a wire 53, the second end of the movable contact 22 is bent and extended along the direction far away from the receiving groove 213, the first end of the connecting portion 212 is provided with a pair of rotating portions 214, the pair of rotating portions 214 are respectively protruded on the front side and the back side of the connecting portion 212 for being in rotation fit with the housing, fig. 3 and 4, the end faces of the two connecting portions 212 are provided with grooves, the two grooves are respectively in rotation fit with the base 12 and the connecting shaft 13 of the upper cover 11, the inner side of the second end of the connecting portion 212 is provided with a pair of arc blocking plates 215, the pair of arc blocking plates 215 are respectively protruded on the edges of the front side and the back side of the second end of the connecting portion 212, in the figure, the second end of the connecting portion 212 is a right angle, each arc blocking plate 215 is integrally L-shaped, one end of each arc blocking plate 215 is connected with the cover plate 211, and the other end extends to the two sides of the movable contact 22 in the direction close to the second end of the connecting portion 212.

As shown in fig. 1, 2, 5 and 6, a mounting groove for mounting the fixed contact assembly is formed in the inner side wall of the housing, the mounting groove is located at a side close to the second connection terminal 52, in this embodiment, the mounting groove is formed by surrounding mounting portions 18 respectively arranged on the inner side walls of the base 12 and the upper cover 11, each mounting portion 18 includes two support plates perpendicular to each other, the fixed contact assembly includes a fixed contact plate 32 and a clamp 31, one end of the fixed contact plate 32 is connected to the second connection terminal 52, the other end of the fixed contact plate 32 extends in a direction away from the second connection terminal 52 and is attached to one of the support plates, the clamp 31 is connected to an end of the fixed contact plate 32 away from the second connection terminal 52, the clamp 31 is arranged in a right-angle area formed by the fixed contact plate 32 and the other support plate in fig. 1 and 2, wherein an opening of the clamp 31 faces an isolation cavity, the movable contact 22 is electrically connected with the stationary contact plate 32 after being inserted and matched with the clamp 31.

The foregoing is a more detailed description of the utility model in connection with specific preferred embodiments and it is not intended that the utility model be limited to these specific details. For those skilled in the art to which the utility model pertains, several simple deductions or substitutions can be made without departing from the spirit of the utility model, and all shall be considered as belonging to the protection scope of the utility model.

Claims

1. A disconnecting switch comprises a shell and a contact mechanism arranged in the shell, wherein the contact mechanism comprises a movable contact component and a fixed contact component which are matched with each other, and is characterized in that: the switching-on device is characterized in that an isolation cavity communicated with the outside is arranged in the shell, arc extinguishing grid pieces (14) are arranged on the side wall of the isolation cavity, a moving contact component rotatably assembled in the isolation cavity comprises a linkage piece (21) and a moving contact (22), the first end of the linkage piece (21) is in turn connection with the shell in a rotating fit mode, one inner side of the linkage piece (21) is connected with the moving contact (22) and provided with an arc baffle plate (215) matched with the arc extinguishing grid pieces (14) in a protruding mode around the moving contact (22), in the switching-off process, the linkage piece (21) covers the isolation cavity to enable the moving contact (22) to be matched with the static contact component, and in the switching-off process, the linkage piece (21) turns outwards to enable the moving contact (22) to be separated from the static contact component.

2. A disconnector according to claim 1, characterized in that: one side of the isolation cavity is provided with at least one connecting shaft (13), the first end of the linkage piece (21) is rotatably connected with the connecting shaft (13), the other side of the isolation cavity is provided with two groups of arc-extinguishing grid pieces (14), each group of arc-extinguishing grid pieces (14) are respectively opposite to the positive side and the negative side of the second end of the linkage piece (21), and the movable contact (22) enters the isolation cavity and is positioned between the two groups of arc-extinguishing grid pieces (14).

3. A disconnector according to claim 1, characterized in that: two arc baffles (215) are arranged on the edge of the second end of the linkage piece (21), the two arc baffles (215) are respectively arranged on the front side and the back side of the linkage piece (21) in a protruding mode, and the second end of the movable contact (22) is located between the two arc baffles (215).

4. A disconnector according to claim 1, characterized in that: and a pull ring (4) is arranged on the outer side of the linkage piece (21), and the movable contact assembly is driven to turn outwards by the pull ring (4) to be switched off.

5. A disconnector according to claim 4, characterized in that: one side of the shell is provided with a limiting part (15), the limiting part (15) is provided with a clamping groove (151), and the clamping groove (151) is matched with the pull ring (4) to enable the movable contact assembly to be kept at a brake separating position.

6. A disconnector according to claim 1, characterized in that: the shell is provided with a window opposite to the moving contact component, the window is sealed by a visual clapboard (16), and the opening and closing conditions of the moving contact component can be observed through the visual clapboard (16).

7. A disconnector according to claim 6, characterized in that: the window is positioned on the side wall of the isolation cavity, and a limiting groove (17) for limiting and mounting a visual clapboard (16) is arranged on the inner side wall of the isolation cavity adjacent to the window.

8. A disconnector according to claim 1, characterized in that: the both ends of shell are equipped with first binding post (51) and second binding post (52) respectively, the stationary contact subassembly includes stationary contact board (32) and clamp (31), the one end and the second binding post (52) of stationary contact board (32) are connected, and the other end of stationary contact board (32) extends to the direction that deviates from second binding post (52), clamp (31) are connected in the one end that deviates from second binding post (52) in stationary contact board (32), and the opening of clamp (31) is towards keeping apart the chamber and supplying moving contact (22) to peg graft.

9. A disconnector according to claim 1, characterized in that: the linkage piece (21) comprises a cover plate (211) and a connecting part (212) which are integrally formed, wherein a connecting boss (216) is arranged on one side of the cover plate (211) which is used as the outer side of the linkage piece (21), a pull ring (4) is arranged on the connecting boss (216), the other side of the cover plate (211) is connected with one side of the connecting part (212), an accommodating groove (213) is arranged on the other side of the connecting part (212) which is used as the inner side, a moving contact (22) is assembled in the accommodating groove (213), a pair of rotating parts (214) are arranged at the first end of the connecting part (212), the pair of rotating parts (214) are respectively arranged on the front side and the back side of the connecting part (212) in a protruding mode and are used for being in rotating fit with the shell, a pair of arc blocking plates (215) are arranged at the second end of the connecting part (212), and the pair of arc blocking plates (215) are respectively arranged along the edges of the front side and the back side of the second end of the connecting part (212) in a protruding mode, one end of each arc baffle plate (215) is connected with the cover plate (211), and the other end extends to the two sides of the movable contact (22) in the direction close to the second end of the connecting part (212).

10. A disconnector according to claim 1, characterized in that: the two ends of the shell are respectively provided with a first terminal groove and a second terminal groove, the shell between the first terminal groove and the second terminal groove protrudes outwards to form a convex part, so that the whole shell is in a convex shape with two low ends and a high middle part, one side wall of the convex part is opened, one side of the convex part close to the second terminal groove is provided with two groups of arc-extinguishing grid sheets (14) to form an isolation cavity in the convex part, the two groups of arc-extinguishing grid sheets (14) are respectively arranged on two opposite isolation cavity side walls, one side of the isolation cavity close to the first terminal groove is provided with two connecting shafts (13) which are rotationally matched with a linkage piece (21), the side wall of the isolation cavity far away from the first terminal groove is provided with a window, the window is covered by a visual clapboard (16), one side of each group of arc-extinguishing grid sheets (14) close to the window is provided with a limiting groove (17) for limiting the visual clapboard (16), be equipped with the mounting groove that is used for assembling the stationary contact subassembly in the middle part of the shell that is close to the second terminal groove, the mounting groove is relative with one side that keeps apart the chamber and be equipped with arc extinguishing bars piece (14), and outside protrusion forms spacing portion (15) by a lateral wall that keeps apart the chamber and is close to first terminal groove spacing portion (15) are equipped with draw-in groove (151) towards one side in first terminal groove.