Title of Invention	ARC-EXTINGUISHING DEVICE FOR AN ELECTRICAL SWITCH
Abstract	The invention relates to an arc-extinguishing device (2) for an electrical switch (1) having a plurality of arc-extinguishing plates (23; 123; 223) which have a cutout (38) open on one side and extending in a direction of flow (37), the arc-extinguishing plates (23; 123; 223) being partially coated on at least one side with a gas-emitting material, and on the partially coated sides of the arc-extinguishing plates (23; 123; 223) in each case at least one partial surface of the respective arc-extinguishing plate adjacent to the cutout (38) and extending in the direction of flow (37) being uncoated. To stabilize the arc, it is provided that the uncoated partial surface (39; 139; 239) extends to the end (40) of the respective arc-extinguishing plate (23; 123; 223) in the direction of flow (37).

Title of Invention

ARC-EXTINGUISHING DEVICE FOR AN ELECTRICAL SWITCH

Abstract

The invention relates to an arc-extinguishing device (2) for an electrical switch (1) having a plurality of arc-extinguishing plates (23; 123; 223) which have a cutout (38) open on one side and extending in a direction of flow (37), the arc-extinguishing plates (23; 123; 223) being partially coated on at least one side with a gas-emitting material, and on the partially coated sides of the arc-extinguishing plates (23; 123; 223) in each case at least one partial surface of the respective arc-extinguishing plate adjacent to the cutout (38) and extending in the direction of flow (37) being uncoated. To stabilize the arc, it is provided that the uncoated partial surface (39; 139; 239) extends to the end (40) of the respective arc-extinguishing plate (23; 123; 223) in the direction of flow (37).

Full Text	Description Arc-extinguishing device for an electrical switch The invention relates to an arc-extinguishing device for an electrical switch having a plurality of arc-extinguishing plates which have a cutout open on one side and extending in a direction of flow, the arc-extinguishing plates being partially coated on at least one side with a gas-emitting material, and on the partially coated sides of the arc-extinguishing plates in each case at least one partial surface of the respective arc-extinguishing plate adjacent to the cutout and extending in the direction of flow being uncoated. Furthermore, the invention relates to methods for manufacturing an arc-extinguishing device of this kind and to an electrical switch having an arc-extinguishing device of this kind. The use of gas-emitting materials, particularly in the form of gassing plastics, in arc-extinguishing devices is known in itself. These gassing plastics are distinguished by the fact that, when interacting with a switching arc, gaseous decomposition products are released from the surface of the plastics. These gaseous decomposition products, which are also known under the name of "hard gas", lead to an excess pressure at the point where the arc is extinguished and thus force the arc to extinguish more quickly. Publication DE 3247681 Al shows arc-extinguishing devices of the generic type, in which however each of the arc-extinguishing plates is coated with a gas-emitting material in the rear section viewed in the direction of flow in order to prevent a short-circuiting of individual sub-arcs behind the arc-extinguishing plates and to stabilize the arc in the arc-extinguishing device. Furthermore, in the introductory part of the description, publication DE 102 42 310 Al discloses an arc-extinguishing device of the generic type. This publication also shows a circuit breaker in which, in addition to the arc-extinguishing plates or instead of the arc-extinguishing plates, the arc-extinguishing device has a plate preferably made of Ultramid® A3SK. These plates also serve to stabilize the arc. Starting from an arc-extinguishing device with the characteristics of the pre-characterizing clause of patent claim 1 (DE 3247681 Al), the invention is based on the object of keeping the arc away from critical outer areas and at the same time optimizing the reinforcement of the gas flow in such a way that damaging ions, which may cause reignition of the arc, are reliably removed from the area of the switching contacts. According to the invention, this object is achieved in chat the uncoated partial surface extends to the end of the respective arc-extinguishing plate in the direction of flow. As a rear section of the arc-extinguishing plates - viewed in the direction of flow - remains uncoated in the area above the cutout, no gas flows are produced in this area which could be directed against the direction of flow and therefore toward the switching contacts. Preferably, only the corners of the arc-extinguishing plates formed on both sides of the cutout, or only two strip-shaped lateral end sections of the arc-extinguishing plates adjacent to the two side edges of the arc-extinguishing plates running in the direction of flow, or also only two mutually convex lateral end sections of the arc-extinguishing plates adjacent to the two side edges of the arc-extinguishing plates running in the direction of flow are coated on at least one side with the gas-emitting material. The arc-extinguishing plates of the new arc-extinguishing device can preferably be coated by means of an immersion method. The gas-emitting material can however also be sprayed on. In an advantageous manner, it is also foreseen that a granulate of gas-emitting material be applied and subsequently fused. All these methods have the advantage that they can be automated. An exemplary embodiment of the new arc-extinguishing device is shown in Figures 1 to 7. In the drawing: Figure 1 shows a schematic representation of an electrical switch with an arc-extinguishing device, Figure 2 shows a switching contact system of the electrical switch, which has an arc-extinguishing device according to the invention associated with it, Figure 3 shows the arc-extinguishing device according to Figure 2 in an exploded view, Figures 4 and 5 show the arc-extinguishing device according to Figure 2 in two perspective representations, and Figures 6 to 8 show three embodiments of arc-extinguishing plates of the arc-extinguishing device according to the invention. Figure 1 shows an electrical switch 1 in the form of a low-voltage circuit breaker, which has a switching contact system, an arc-extinguishing device 2 associated with the switching contact system, and a switch pole housing formed from two housing shells 3 and 4. At the same time, the switch pole housing forms an integrated switching chamber 5 for accommodating the switching contact system, and an integrated extinguishing chamber 6 open to the switching chamber 5 and for accommodating the arc-extinguishing device 2. The switching contact system consists of a fixed switching contact arrangement 7 and a moving switching contact arrangement 8. At the same time, the moving switching contact arrangement 8 has a swiveling contact carrier 11 and a plurality of moving switching contacts 12 in the form of contact levers. The moving switching contacts 12 can be swiveled parallel to one another and are spring-supported under pre-tension against the contact carrier 11 by means of two contact force springs 13 in each case. The moving switching contact arrangement 7 is coupled in the usual way to a switching shaft 15 by means of a lever arrangement 14, which is only indicated schematically in Figure 1. At the same time, the switching shaft 15 serves to drive further switching contact systems, which are arranged parallel to the shown switching contact system and are not shown in more detail, each of which has a further arc-extinguishing device associated with it, which is likewise not shown. The switching shaft 15 is to be transferred from an off position, in which the switching contact systems are open, into an on position, in which the switching contact systems are closed, by means of a drive device 16. When the switching shaft 15 is transferred into its on position, the contact force springs 13 are further tensioned. The drive device 16 has a drive 18 fitted with a storage spring 17, a drive train 19 coupling the drive 18 to the switching shaft 15, and a latching mechanism 20. As shown in Figures 2 to 5, each of the arc-extinguishing devices 2 consists of two insulating walls 22 made from fiber or fire-resistant plastic, as well as arc-extinguishing plates 23 and arc guide plates 24, 25 made from sheet steel. The arc-extinguishing plates 23 and the arc guide plates 24, 25 are provided with tabs 26, which are fed into holes 27 of the insulating walls 22 and fixed in place (riveted). This produces a pack of extinguishing plates, which is placed in the extinguishing chamber 6. The arc-extinguishing device 2 furthermore has a lockable cover 28, which is provided with blow-out slots 29, lateral molded projections 30 and a through opening 31. The lateral molded projections 30 engage in slots 33 of the insulating walls 22 in order to fix the cover 2 8 to the pack of extinguishing plates. A fixing screw 21, which passes through the through opening 31 and engages in a threaded hole associated with it in one of the two housing shells 3 of the switch pole housing, is used to fix the arc-extinguishing device 2 in the extinguishing chamber 6. As shown in Figure 2, the flat arc guide plate 24, which forms an outer side of the pack of extinguishing plates running perpendicular to the insulating plates, is associated with the fixed switching contact arrangement 7. The arc guide plate 25, which likewise forms an outer side of the pack of extinguishing plates running perpendicular to the insulating plates, is associated with the moving switching contact arrangement 8. It has a first part 34 running parallel to the arc-extinguishing plates 23, and a bend 35, which is inclined in opposition to the opening direction 32 of the moving switching contacts 12. The free end of these bends 41 is a short distance from the movement paths of the free ends of the moving switching contacts 12, which free ends are designed as arc horns 36. This guarantees an optimum transition of the arc base from the arc horns 36 to the arc guide plate 25. As shown in Figures 5 to 8, all embodiments of the plurality of arc-extinguishing plates 23; 123; 223, which are arranged parallel to one another, have a cutout 38 open on one side toward the switching contact system and running in the direction of flow 37 of the switching gases. At the same time, the arc-extinguishing plates 23; 123; 223 are in each case only partially coated on both sides with a gas-emitting material in the form of a plastic so that a partial surface 39; 139; 239 adjacent to the narrowest point of the cutout 38 and extending in the direction of flow as far as the rear end 40 of the arc-extinguishing plate 23; 123; 223 - viewed in the direction of flow 37 - remains uncoated. The first embodiment of the arc-extinguishing plates 23 already shown in Figure 5 is shown again in Figure 6. With this first embodiment, only the corners 41, 42 of the arc-extinguishing plate 23 formed on both sides of the cutout 38 are each coated on both sides with the gas-emitting material so that the partial surface 39, which extends to the rear end 40 of the arc-extinguishing plate 23, therefore remains uncoated. Figure 6 shows a second embodiment of arc-extinguishing plates 123 in which only two strip-shaped lateral end sections 45, 46 of the arc-extinguishing plates 123 adjacent to the two side edges 43, 44 of the arc-extinguishing plates 123 running in the direction of flow 37 are coated on both sides with the gas-emitting material. Here too, the partial surface 139, which extends to the rear end 40 of the arc-extinguishing plate 123 -viewed in the direction of flow 37 -, remains uncoated. Furthermore, Figure 8 shows a third embodiment of arc-extinguishing plates 223 in which only two mutually convex lateral end sections 47, 48 of the arc-extinguishing plates 223 adjacent to the two side edges 43, 44 of the arc-extinguishing plates 223 running in the direction of flow 37 are coated on both sides with the gas-emitting material. In doing so, the coated corners 41, 42 or lateral end sections 45, 46; 47, 4 8 form less than one third of the total arc-extinguishing plates 23; 123 and 223 respectively. All three embodiments shown of the arc-extinguishing plates 23; 123; 223 are distinguished by an objective arrangement of the gas-emitting coated partial surfaces (areas) and therefore also by an objective arrangement of the uncoated partial surfaces (areas) on the arc-extinguishing plates, which along with a forced cooling on the one hand drives the arc into the middle uncoated area of the arc-extinguishing plates and thereby keeps it away from critical lateral outer areas, and which on the other, by reinforcing the gas flow in the whole area above the cutout, also quickly removes ions from the contact area of the switching contact system in order to reliably prevent reignition of the arc in the contact area of the switching contact system. Further embodiments of arc-extinguishing plates can of course be used. In particular, each of the extinguishing plates can be provided with a coating on only one side. Here, preferably, r.he same side is to be coated in each case so that, in spite of this, a layer of gas-emitting material is situated between adjacent extinguishing plates in each case. The arc-extinguishing plates can be partially coated with a plastic, which forms gas under the effect of the arc, by means of an immersion method. The gas-emitting material can however also be sprayed on or applied in the form of a granulate of gas-emitting material and subsequently fused. The new arc-extinguishing device is distinguished by a considerably improved extinguishing behavior and therefore by an improved ratio between switching chamber volume and switching power. Therefore, either the switching chamber volume can be reduced for the same switching power or the switching power can be increased for the same switching chamber volume. Other solutions for stabilizing the arc within the pack of extinguishing plates, which are more elaborate with regard to assembly, - for example in the form of arc guiding elements made of copper, such as are disclosed in DE 102 50 950 34 - can be dispensed with. This reliably eliminates risk to personnel (for example due to failures to extinguish in the event of a short circuit), so that no further protective measures, in particular no additional protective covers for the insulating walls, are required. Patent claims 1. An arc-extinguishing device (2) for an electrical switch (1) - having a plurality of arc-extinguishing plates (23; 123; 223) which have a cutout (38) open on one side and extending in a direction of flow (37), - the arc-extinguishing plates (23; 123; 223) being partially coated on at least one side with a gas-emitting material, and - on the partially coated sides of the arc-extinguishing plates (23; 123; 223) in each case at least one partial surface of the respective arc-extinguishing plate adjacent to the cutout (38) and extending in the direction of flow (37) being uncoated, characterized in that the uncoated partial surface (39; 139; 239) extends to the end (40) of the respective arc-extinguishing plate (23; 123; 223) in the direction of flow (37) . 2. The arc-extinguishing device (2) as claimed in claim 1, characterized in that only the corners (41, 42) of the arc- extinguishing plates (23) formed on both sides of the cutout (38) have a layer of the gas-emitting material on at least one side. 3. The arc-extinguishing device (2) as claimed in claim 1, characterized in that only two strip-shaped lateral end sections (45, 46) of the arc-extinguishing plates (123) adjacent to the two side edges (43, 44) of the arc-extinguishing plates (123) running in the direction of flow have a layer of the gas-emitting material on at least one side. 4. The arc-extinguishing device (2) as claimed in claim 3, characterized in that only two mutually convex lateral end sections (47, 48) of the arc-extinguishing plates (223) adjacent to the two side edges of the arc-extinguishing plates (223) running in the direction of flow have a layer of the gas-emitting material on at least one side. 5. The arc-extinguishing device (2) as claimed in one of claims 1 to 4, characterized in that the gas-emitting material is a plastic. 6. A method for manufacturing the arc-extinguishing device (2) as claimed in one of claims 1 to 5, characterized in that the gas-emitting material is applied by means of an immersion method. 7. A method for manufacturing the arc-extinguishing device (2) as claimed in one of claims 1 to 5, characterized in that the gas-emitting material is sprayed on. 8. A method for manufacturing the arc-extinguishing device (2) as claimed in one of claims 1 to 5, characterized in that a granulate of gas-emitting material is applied and subsequently fused. 9. An electrical switch (1) having an arc-extinguishing device (2), characterized in that the arc-extinguishing device (2) is designed as claimed in one of claims 1 to 5. The invention relates to an arc-extinguishing device (2) for an electrical switch (1) having a plurality of arc-extinguishing plates (23; 123; 223) which have a cutout (38) open on one side and extending in a direction of flow (37), the arc-extinguishing plates (23; 123; 223) being partially coated on at least one side with a gas-emitting material, and on the partially coated sides of the arc-extinguishing plates (23; 123; 223) in each case at least one partial surface of the respective arc-extinguishing plate adjacent to the cutout (38) and extending in the direction of flow (37) being uncoated. To stabilize the arc, it is provided that the uncoated partial surface (39; 139; 239) extends to the end (40) of the respective arc-extinguishing plate (23; 123; 223) in the direction of flow (37).

Full Text

Description
Arc-extinguishing device for an electrical switch
The invention relates to an arc-extinguishing device for an electrical switch having a plurality of arc-extinguishing plates which have a cutout open on one side and extending in a direction of flow, the arc-extinguishing plates being partially coated on at least one side with a gas-emitting material, and on the partially coated sides of the arc-extinguishing plates in each case at least one partial surface of the respective arc-extinguishing plate adjacent to the cutout and extending in the direction of flow being uncoated.
Furthermore, the invention relates to methods for manufacturing an arc-extinguishing device of this kind and to an electrical switch having an arc-extinguishing device of this kind.
The use of gas-emitting materials, particularly in the form of gassing plastics, in arc-extinguishing devices is known in itself. These gassing plastics are distinguished by the fact that, when interacting with a switching arc, gaseous decomposition products are released from the surface of the plastics. These gaseous decomposition products, which are also known under the name of "hard gas", lead to an excess pressure at the point where the arc is extinguished and thus force the arc to extinguish more quickly.
Publication DE 3247681 Al shows arc-extinguishing devices of the generic type, in which however each of the arc-extinguishing plates is coated with a gas-emitting material in the rear section viewed in the direction of flow in order to prevent a short-circuiting of individual sub-arcs behind the arc-extinguishing plates and to stabilize the arc in the arc-extinguishing device.

Furthermore, in the introductory part of the description, publication DE 102 42 310 Al discloses an arc-extinguishing device of the generic type. This publication also shows a circuit breaker in which, in addition to the arc-extinguishing plates or instead of the arc-extinguishing plates, the arc-extinguishing device has a plate preferably made of Ultramid® A3SK. These plates also serve to stabilize the arc.
Starting from an arc-extinguishing device with the characteristics of the pre-characterizing clause of patent claim 1 (DE 3247681 Al), the invention is based on the object of keeping the arc away from critical outer areas and at the same time optimizing the reinforcement of the gas flow in such a way that damaging ions, which may cause reignition of the arc, are reliably removed from the area of the switching contacts.
According to the invention, this object is achieved in chat the uncoated partial surface extends to the end of the respective arc-extinguishing plate in the direction of flow. As a rear section of the arc-extinguishing plates - viewed in the direction of flow - remains uncoated in the area above the cutout, no gas flows are produced in this area which could be directed against the direction of flow and therefore toward the switching contacts.
Preferably, only the corners of the arc-extinguishing plates formed on both sides of the cutout, or only two strip-shaped lateral end sections of the arc-extinguishing plates adjacent to the two side edges of the arc-extinguishing plates running in the direction of flow, or also only two mutually convex lateral end sections of the arc-extinguishing plates adjacent to the two side edges of the arc-extinguishing plates running in the direction of flow are coated on at least one side with the gas-emitting material.

The arc-extinguishing plates of the new arc-extinguishing device can preferably be coated by means of an immersion method. The gas-emitting material can however also be sprayed on. In an advantageous manner, it is also foreseen that a granulate of gas-emitting material be applied and subsequently fused. All these methods have the advantage that they can be automated.
An exemplary embodiment of the new arc-extinguishing device is shown in Figures 1 to 7.
In the drawing:
Figure 1 shows a schematic representation of an electrical
switch with an arc-extinguishing device,
Figure 2 shows a switching contact system of the electrical
switch, which has an arc-extinguishing device according to the
invention associated with it,
Figure 3 shows the arc-extinguishing device according to Figure
2 in an exploded view,
Figures 4 and 5 show the arc-extinguishing device according to
Figure 2 in two perspective representations, and
Figures 6 to 8 show three embodiments of arc-extinguishing
plates of the arc-extinguishing device according to the
invention.
Figure 1 shows an electrical switch 1 in the form of a low-voltage circuit breaker, which has a switching contact system, an arc-extinguishing device 2 associated with the switching contact system, and a switch pole housing formed from two housing shells 3 and 4. At the same time, the switch pole housing forms an integrated switching chamber 5 for accommodating the switching contact system, and an integrated extinguishing chamber 6 open to the switching chamber 5 and for accommodating the arc-extinguishing device 2. The switching contact system consists of a fixed switching contact arrangement 7 and a moving switching contact arrangement 8. At the same time, the moving switching contact arrangement 8 has a

swiveling contact carrier 11 and a plurality of moving switching contacts 12 in the form of contact levers. The moving switching contacts 12 can be swiveled parallel to one another and are spring-supported under pre-tension against the contact carrier 11 by means of two contact force springs 13 in each case. The moving switching contact arrangement 7 is coupled in the usual way to a switching shaft 15 by means of a lever arrangement 14, which is only indicated schematically in Figure 1. At the same time, the switching shaft 15 serves to drive further switching contact systems, which are arranged parallel to the shown switching contact system and are not shown in more detail, each of which has a further arc-extinguishing device associated with it, which is likewise not shown. The switching shaft 15 is to be transferred from an off position, in which the switching contact systems are open, into an on position, in which the switching contact systems are closed, by means of a drive device 16. When the switching shaft 15 is transferred into its on position, the contact force springs 13 are further tensioned. The drive device 16 has a drive 18 fitted with a storage spring 17, a drive train 19 coupling the drive 18 to the switching shaft 15, and a latching mechanism 20.
As shown in Figures 2 to 5, each of the arc-extinguishing devices 2 consists of two insulating walls 22 made from fiber or fire-resistant plastic, as well as arc-extinguishing plates 23 and arc guide plates 24, 25 made from sheet steel. The arc-extinguishing plates 23 and the arc guide plates 24, 25 are provided with tabs 26, which are fed into holes 27 of the insulating walls 22 and fixed in place (riveted). This produces a pack of extinguishing plates, which is placed in the extinguishing chamber 6. The arc-extinguishing device 2 furthermore has a lockable cover 28, which is provided with blow-out slots 29, lateral molded projections 30 and a through opening 31. The lateral molded projections 30 engage in slots 33 of the insulating walls 22 in order to fix the cover 2 8 to the pack of extinguishing plates. A fixing screw 21, which passes through the through opening 31 and engages in a threaded

hole associated with it in one of the two housing shells 3 of the switch pole housing, is used to fix the arc-extinguishing device 2 in the extinguishing chamber 6.
As shown in Figure 2, the flat arc guide plate 24, which forms an outer side of the pack of extinguishing plates running perpendicular to the insulating plates, is associated with the fixed switching contact arrangement 7. The arc guide plate 25, which likewise forms an outer side of the pack of extinguishing plates running perpendicular to the insulating plates, is associated with the moving switching contact arrangement 8. It has a first part 34 running parallel to the arc-extinguishing plates 23, and a bend 35, which is inclined in opposition to the opening direction 32 of the moving switching contacts 12. The free end of these bends 41 is a short distance from the movement paths of the free ends of the moving switching contacts 12, which free ends are designed as arc horns 36. This guarantees an optimum transition of the arc base from the arc horns 36 to the arc guide plate 25.
As shown in Figures 5 to 8, all embodiments of the plurality of arc-extinguishing plates 23; 123; 223, which are arranged parallel to one another, have a cutout 38 open on one side toward the switching contact system and running in the direction of flow 37 of the switching gases. At the same time, the arc-extinguishing plates 23; 123; 223 are in each case only partially coated on both sides with a gas-emitting material in the form of a plastic so that a partial surface 39; 139; 239 adjacent to the narrowest point of the cutout 38 and extending in the direction of flow as far as the rear end 40 of the arc-extinguishing plate 23; 123; 223 - viewed in the direction of flow 37 - remains uncoated.
The first embodiment of the arc-extinguishing plates 23 already shown in Figure 5 is shown again in Figure 6. With this first embodiment, only the corners 41, 42 of the arc-extinguishing plate 23 formed on both sides of the cutout 38 are each coated

on both sides with the gas-emitting material so that the partial surface 39, which extends to the rear end 40 of the arc-extinguishing plate 23, therefore remains uncoated.
Figure 6 shows a second embodiment of arc-extinguishing plates 123 in which only two strip-shaped lateral end sections 45, 46 of the arc-extinguishing plates 123 adjacent to the two side edges 43, 44 of the arc-extinguishing plates 123 running in the direction of flow 37 are coated on both sides with the gas-emitting material. Here too, the partial surface 139, which extends to the rear end 40 of the arc-extinguishing plate 123 -viewed in the direction of flow 37 -, remains uncoated.
Furthermore, Figure 8 shows a third embodiment of arc-extinguishing plates 223 in which only two mutually convex lateral end sections 47, 48 of the arc-extinguishing plates 223 adjacent to the two side edges 43, 44 of the arc-extinguishing plates 223 running in the direction of flow 37 are coated on both sides with the gas-emitting material.
In doing so, the coated corners 41, 42 or lateral end sections 45, 46; 47, 4 8 form less than one third of the total arc-extinguishing plates 23; 123 and 223 respectively.
All three embodiments shown of the arc-extinguishing plates 23; 123; 223 are distinguished by an objective arrangement of the gas-emitting coated partial surfaces (areas) and therefore also by an objective arrangement of the uncoated partial surfaces (areas) on the arc-extinguishing plates, which along with a forced cooling on the one hand drives the arc into the middle uncoated area of the arc-extinguishing plates and thereby keeps it away from critical lateral outer areas, and which on the other, by reinforcing the gas flow in the whole area above the cutout, also quickly removes ions from the contact area of the switching contact system in order to reliably prevent reignition of the arc in the contact area of the switching contact system.

Further embodiments of arc-extinguishing plates can of course be used. In particular, each of the extinguishing plates can be provided with a coating on only one side. Here, preferably, r.he same side is to be coated in each case so that, in spite of this, a layer of gas-emitting material is situated between adjacent extinguishing plates in each case.
The arc-extinguishing plates can be partially coated with a plastic, which forms gas under the effect of the arc, by means of an immersion method. The gas-emitting material can however also be sprayed on or applied in the form of a granulate of gas-emitting material and subsequently fused.
The new arc-extinguishing device is distinguished by a considerably improved extinguishing behavior and therefore by an improved ratio between switching chamber volume and switching power. Therefore, either the switching chamber volume can be reduced for the same switching power or the switching power can be increased for the same switching chamber volume.
Other solutions for stabilizing the arc within the pack of extinguishing plates, which are more elaborate with regard to assembly, - for example in the form of arc guiding elements made of copper, such as are disclosed in DE 102 50 950 34 - can be dispensed with. This reliably eliminates risk to personnel (for example due to failures to extinguish in the event of a short circuit), so that no further protective measures, in particular no additional protective covers for the insulating walls, are required.

Patent claims
1. An arc-extinguishing device (2) for an electrical
switch (1)
- having a plurality of arc-extinguishing plates (23; 123; 223) which have a cutout (38) open on one side and extending in a direction of flow (37),
- the arc-extinguishing plates (23; 123; 223) being partially coated on at least one side with a gas-emitting material, and
- on the partially coated sides of the arc-extinguishing plates (23; 123; 223) in each case at least one partial surface of the respective arc-extinguishing plate adjacent to the cutout (38) and extending in the direction of flow (37) being uncoated, characterized in that the uncoated partial surface (39; 139; 239) extends to the end (40) of the respective arc-extinguishing plate (23; 123; 223) in the direction of flow
(37) .
2. The arc-extinguishing device (2) as claimed in claim 1,
characterized in that only the corners (41, 42) of the arc-
extinguishing plates (23) formed on both sides of the cutout
(38) have a layer of the gas-emitting material on at least one
side.
3. The arc-extinguishing device (2) as claimed in claim 1, characterized in that only two strip-shaped lateral end sections (45, 46) of the arc-extinguishing plates (123) adjacent to the two side edges (43, 44) of the arc-extinguishing plates (123) running in the direction of flow have a layer of the gas-emitting material on at least one side.
4. The arc-extinguishing device (2) as claimed in claim 3, characterized in that only two mutually convex lateral end sections (47, 48) of the arc-extinguishing plates (223) adjacent to the two side edges of the arc-extinguishing plates (223) running in the direction of flow have a layer of the gas-emitting material on at least one side.

5. The arc-extinguishing device (2) as claimed in one of claims 1 to 4, characterized in that the gas-emitting material is a plastic.
6. A method for manufacturing the arc-extinguishing device (2) as claimed in one of claims 1 to 5, characterized in that the gas-emitting material is applied by means of an immersion method.
7. A method for manufacturing the arc-extinguishing device (2) as claimed in one of claims 1 to 5, characterized in that the gas-emitting material is sprayed on.
8. A method for manufacturing the arc-extinguishing device (2) as claimed in one of claims 1 to 5, characterized in that a granulate of gas-emitting material is applied and subsequently fused.
9. An electrical switch (1) having an arc-extinguishing device (2), characterized in that the arc-extinguishing device (2) is designed as claimed in one of claims 1 to 5.

The invention relates to an arc-extinguishing device (2) for an electrical switch (1) having a plurality of arc-extinguishing plates (23; 123; 223) which have a cutout (38) open on one side and extending in a direction of flow (37), the arc-extinguishing plates (23; 123; 223) being partially coated on at least one side with a gas-emitting material, and on the partially coated sides of the arc-extinguishing plates (23; 123; 223) in each case at least one partial surface of the respective arc-extinguishing plate adjacent to the cutout (38) and extending in the direction of flow (37) being uncoated.
To stabilize the arc, it is provided that the uncoated partial surface (39; 139; 239) extends to the end (40) of the respective arc-extinguishing plate (23; 123; 223) in the direction of flow (37).

ARC-EXTINGUISHING DEVICE FOR AN ELECTRICAL SWITCH

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