SWITCHING DEVICE WITH ARC EXTINGUISHING DEVICE AND ARC GUIDE

Abstract

The present invention relates to a switching device comprising at least one contact point, an arc extinguishing chamber assigned to the contact point, and an arc blow device assigned to the contact point. The arc extinguishing chamber comprises an exit opening through which plasma, which is generated inside the switching device by a switch arc developing when the contact point opens, can exit out of the switching device, the exit opening having a clearance dimension and defining an exit plane. The arc blow device is provided for generating a magnetic blow field by which the switch arc developing when the contact point opens is blown away from the contact point towards the exit opening. Furthermore, the switching device comprises at least one first arc guide plate which extends from the contact point to the exit opening and by which the switch arc is guided and stretched on the way from the contact point to the exit opening, wherein the first arc guide plate comprises a first portion and a second portion within the arc extinguishing chamber between the contact point and the exit plane, the first portion of the first arc guide plate being arranged proximal to the contact point, and the second portion of the first arc guide plate being arranged distal to the contact point. According to the invention it is provided that the second portion of the first arc guide plate extends beyond the exit opening in a direction parallel to the exit plane so that the switch arc is stretched by the second portion of the first arc guide plate at least at one end of the switch arc beyond the clearance dimension of the exit opening, wherein an arc guide pin projecting from the second portion of the first arc guide plate is arranged in front of the exit opening, by which arc guide pin the switch arc is again shortened in front of the exit opening.

Claims

1. Switching device (1) comprising at least one contact point (2), an arc extinguishing chamber assigned to the contact point and having an exit opening (3) through which plasma, which is generated inside the switching device by a switch arc (4, 4, 4) developing when the contact point opens, can exit out of the switching device, the exit opening having a clearance dimension (5) and defining an exit plane (6), and an arc blow device assigned to the contact point (2) for generating a magnetic blow field by which the switch arc (4, 4, 4) developing when the contact point opens is blown away from the contact point (2) towards the exit opening (3), the switching device (1) comprising at least one first arc guide plate (8) which extends from the contact point (2) to the exit opening (3) and by which the switch arc (4, 4, 4) is guided and stretched on the way from the contact point to the exit opening, the first arc guide plate (8) comprising a first portion (9) and a second portion (10) within the arc extinguishing chamber between the contact point (2) and the exit plane (6), the first portion (9) of the first arc guide plate being arranged proximal to the contact point, and the second portion (10) of the first arc guide plate being arranged distal to the contact point, characterized in that the second portion (10) of the first arc guide plate (8) extends beyond the exit opening (3) in a direction parallel to the exit plane (6) so that the switch arc (4, 4, 4) is stretched by the second portion (10) of the first arc guide plate (8) at least at one end of the switch arc beyond the clearance dimension (5) of the exit opening (3), wherein an arc guide pin (12) projecting from the second portion (10) of the first arc guide plate (8) is arranged in front of the exit opening (3), by which arc guide pin the switch arc is again shortened in front of the exit opening.

2. Switching device (1) according to claim 1, characterized in that the arc guide pin (12) projects perpendicularly from the second portion (10) of the first arc guide plate (8).

3. Switching device (1) according to claim 1, characterized in that the arc guide pin (12) ends in a direction which runs parallel to the exit plane (6), approximately at the level of the exit opening (3), so that the switch arc (4, 4, 4) is shortened by the arc guide pin (12) to the clearance dimension (5) of the exit opening (3).

4. Switching device (1) according to claim 1, characterized in that the arc guide pin (12) comprises a guide plate-side end with a threaded portion (14), wherein the threaded portion (14) is screwed to a corresponding internal thread of a bore (15) in the first arc guide plate (8).

5. Switching device (1) according to claim 1, characterized in that the arc guide pin (12) has a chamfer (16) at its end facing away from the first arc guide plate (8).

6. Switching device (1) according to claim 1, characterized in that the arc extinguishing chamber comprises a plurality of extinguishing elements (13) which are each arranged spaced apart from one another in the exit opening (3), wherein the plasma which is generated by the switch arc (4, 4, 4) inside the switching device (1) is able to exit out of the exit opening (3) between and through the extinguishing elements (13).

7. Switching device (1) according to claim 1, characterized in that the first arc guide plate (8) comprises a third portion (11) which adjoins the second portion (10) and is guided out of a housing (20) of the switching device (1) and simultaneously forms a first terminal contact (11) of the switching device (1).

8. Switching device (1) according to claim 7, characterized in that a connecting bolt (17) of the first terminal contact (11) is arranged between the first arc guide plate (8) and the exit opening (3).

9. Switching device (1) according to claim 1, characterized in that a fixed contact (18) of the contact point (2) is part of the first arc guide plate (8), wherein the first portion (9) of the first arc guide plate (8) directly adjoins the fixed contact (18) and is angled relative to the fixed contact (18), so that the switch arc (4, 4, 4) is stretched by the first portion (9), wherein at least a part (10.2) of the second portion (10) of the first arc guide plate (8) is again angled relative to the first portion (9) and extends substantially in parallel with the fixed contact (18).

10. Switching device (1) according to claim 1, characterized in that the switching device (1) further comprises a second arc guide plate (19), wherein first and second arc guide plates (8, 19) diverge starting from the contact point (2) in such a way that the switch arc (4. 4, 4, 4) is first stretched to a length which lies above the clearance dimension (5) of the exit opening (3), wherein the switch arc (4, 4, 4) is shortened again in front of the exit opening (3) as a result of the arc guide pin (12).

11. Switching device (1) according to claim 1, characterized in that the arc guide pin (12) is a bracket that extends transversely to the first arc guide plate (8), and the free ends of which are attached to the first arc guide plate (8).

Description

[0019] Embodiments of the present invention shall be explained in more detail hereinafter with reference to the drawings.

[0020] FIG. 1 shows a schematic oblique view of a switching device according to the invention according to a first embodiment with a housing shown in the opened state for reasons of illustration,

[0021] FIG. 2 shows the switching device according to the invention of FIG. 1 in a side view,

[0022] FIG. 3 shows a detail view of the first arc guide plate of the switching device according to the invention of FIGS. 1 and 2 with unscrewed arc guide pin,

[0023] FIG. 4 shows a modification of the switching device according to the invention of FIGS. 1 to 3 in a side view, and

[0024] FIG. 5 shows the detail view of FIG. 3 with an alternative arc guide pin.

[0025] FIG. 1 shows a switching device 1 according to the invention according to a first embodiment of the present invention in an oblique view. The side of the housing 20 of the switching device 1 facing the viewer is not shown to allow a view of the inner workings of the switching device 1.

[0026] A contact point 2 of the switching device 1 is arranged inside the housing 20. The contact point 2 comprises a fixed contact 18 and a movable contact 21 which is located on a contact bridge and which can be brought into contact with the fixed contact 18 by means of a drive (not shown) of the switching device according to the invention. Of the drive of the switching device, only the anchor rod 22 connected to the contact bridge is shown in the representation.

[0027] The contact point 2 is associated with an arc extinguishing chamber which on the left housing side comprises an exit opening 3 through which plasma, which is generated within the switching device by a switch arc developing when the contact point opens, can exit out of the switching device. In FIG. 2, which shows a side view of the switching device according to the invention, it can be seen that the exit opening has a clearance dimension 5 and defines an exit plane 6. The arc extinguishing chamber comprises a plurality of extinguishing elements 13, each of which is arranged spaced apart from one another in the exit opening in such a way that the plasma generated by the switch arc inside the switching device can exit between and through the extinguishing elements 13 out of the exit opening 3. As shown in FIGS. 1 and 2, the extinguishing chamber may comprise a further exit opening on the upper side of the switching device 1 according to the invention, in which further exit opening corresponding extinguishing elements 13 are also arranged. In the illustrated embodiment, the exit opening on the upper side of the housing is associated with both the contact point 2 shown and a second contact point not shown on the right-hand side of the contact bridge.

[0028] The contact point 2 is further associated with an arc blow device for generating a magnetic blow field by which the switch arc developing when the contact point opens is blown away from the contact point 2 towards the exit opening 3. The arc blow device comprises the blow magnet 7 shown in FIGS. 1 and 2 and two pole plates arranged parallel to each other and parallel to the image plane of FIG. 2.

[0029] The switch arc developing when the contact point opens is shown in FIG. 2 and marked there with reference sign 4. In order to guide and stretch the switch arc on the way from the contact point 2 to the exit opening 3, the switching device comprises a first arc guide plate 8 and a second arc guide plate 19. The two arc guide plates 8 and 19 diverge starting from the contact point in order to bring about the stretching of the switch arc. The first arc guide plate 8 is made in one piece with the fixed contact 18 and connects it to a terminal contact of the switching device 1. It comprises a first portion 9 directly adjoining the fixed contact 18, a second portion 10 directly adjoining the first portion and a third portion 11 directly adjoining the second portion. The portion 11 is led out of the housing 20 of the switching device according to the invention and at the same time forms a terminal contact of the switching device. It comprises an upwardly projecting connecting bolt which is located directly under the exit opening 3 or under the extinguishing elements 13 arranged in the exit opening 3. The connecting bolt 17 points upwards because, below the third portion 11 of the first arc guide plate 8, space must be provided due to the construction for corresponding attachments of the switching device 1 according to the invention. The exit opening 3 therefore does not extend downwards to the third portion of the first arc guide plate 8 but ends with some distance just above the connecting bolt 17.

[0030] FIG. 2 shows that the first portion 9 of the first arc guide plate 8 is angled with respect to the fixed contact 18 so that the switch arc 4 can be stretched on the way from the contact point to the exit opening. A first part 10.1 of the second portion 10 of the first arc guide plate 8 forms, so to speak, a pure extension of the first portion 9. The switch arc is stretched downwards by the first part 10.1 of the second portion beyond the clearance dimension 8 of the exit opening.

[0031] This stretched state of the switch arc is marked in FIG. 2 with reference sign 4. A second part 10.2 of the second portion 10 of the first arc guide plate 8 is angled with respect to the first part 10.1 or with respect to the first portion 9 and extends at a right angle to the exit plane 6. The second part 10.2 of the second portion 10 thus extends parallel to the fixed contact 18. The lower base point of the switch arc is guided on the second part 10.2 of the second portion 10 of the arc guide plate 8 to shortly before the exit opening. Shortly before the exit opening there is arranged an arc guide pin 12 projecting from the second part 10.2, which shortens the switch arc again before the exit opening. The lower base point of the switch arc travels onto the tip of the arc guide pin 12 and stops there when the switch arc is driven into the extinguishing elements 13. The position of the switch arc directly in front of the extinguishing elements 13 is marked in FIG. 2 with reference sign 4. As the illustrations show, the arc guide pin 12 ends in a direction parallel to the exit plane 6, approximately at the level of the lower exit opening limit, so that the switch arc in the lower region is shortened by the arc guide pin to the clearance dimension of the exit opening.

[0032] The arc guide pin 12 is configured as a simple cylindrical bolt. FIG. 3 shows that the arc guide pin 12 has a guide plate-side end with a threaded portion 14, which can be screwed into the first arc guide plate 8 with a corresponding internal thread of a bore 15. The arc guide pin 12 can therefore be easily screwed to the guide plate 8. At its upper end facing away from the first arc guide plate 8, the arc guide pin 12 comprises a chamfer 16 to prevent a melting loss of the upper end of the arc guide pin 12 caused by the switch arc.

[0033] FIG. 4 shows a modification of the switching device 1 according to the invention of FIGS. 1 to 3 in a side view corresponding to FIG. 2. In this embodiment, the upper exit opening is not provided. The first arc guide plate 8 and the second arc guide plate 19 enclose the lateral exit opening like clamps, wherein the first arc guide plate is spaced from the lower end of the exit opening, as in the embodiment of FIGS. 1 and 2, and the second arc guide plate 19 runs directly towards the upper end of the exit opening. Here, too, the switch arc stretched inside the switching device is shortened to the clearance dimension 5 of the exit opening shortly before entry into the extinguishing elements.

[0034] FIG. 5 shows an alternative embodiment of the arc guide pin 12. The alternative embodiment of the arc guide pin can be used with both previously described embodiments of the invention. The alternative arc guide pin 12 of FIG. 5 is a U-shaped bracket that extends transversely to the first arc guide plate 8 and the free ends of which are attached to the first arc guide plate. Both free ends of the bracket at the guide plate-side end of the arc guide pin 12 can for example be screwed to the first arc guide plate. The bracket extends preferably transversely to the first arc guide plate over at least 50% of the width of the first arc guide plate.