PYROTECHNIC CIRCUIT BREAKER

Abstract

The invention relates to a pyrotechnic current breaker (1) for severing a bus bar (2), comprising a first detonator (7) for passive tripping and a second detonator (14) for active tripping. Both act on a severing piston (9), which severs the bus bar (2) at at least one severing point (5a, 5b) in the event of tripping. The first detonator (7) is connected, by means of two conductors (8a, 8b), to the two sides of a fuse, through which the current through the bus bar (2) flows, while the second detonator (14) has contacts (15a, 15b) for the connecting of an external tripping device. According to the invention, one of the Iwo detonators, preferably the first detonator (7), is disposed in the severing piston (9). The fuse is preferably formed integrally with the bus bar (2), the fuse being formed either by the severing point(s) (5a, 5b) or by a weakened region between two severing points (5a, 5b). It can easily be provided that, in the event of tripping, at least one conductor (8a, 8b) is interrupted in order to prevent an arc in the first detonator (7), e.g. by virtue of the fact that at least one conductor (8a, 8b) is disposed in the path of motion of the severing piston (9).

Claims

1. A pyrotechnic current breaker with passive and active triggering for severing a busbar through which electric current flows, the breaker comprising: a housing through which passes the busbar that is formed with at least one break point and an adjacent fuse part; a separating punch shiftable in the housing past the busbar to cut same; a first igniter for passive triggering and moving the punch past the busbar; and a second igniter for active triggering and moving the punch past the busbar, both of the igniters acting on the separating punch such that, when triggered, the separating punch cuts the busbar at the break point, the first igniter having two conductors connected to two sides of the fuse part and the second igniter having contacts connectable to an external trigger, one of the igniters being in the separating punch.

2. The current breaker according to claim 1, wherein the first igniter is in the separating punch.

3. The current breaker according to claim 1, wherein for electrically insulating the two igniters, the current breaker comprises: a drive piston between the separating punch and the other second igniter.

4. The current breaker according to claim 3, further comprising: an extinguishing agent.

5. The current breaker according to claim 4, wherein the extinguishing agent is in a groove on an outer surface of the separating punch.

6. The current breaker according to claim 4, wherein the extinguishing agent is in a groove on an outer surface of the drive piston.

7. The current breaker according to claim 4, wherein the extinguishing agent is between the drive piston and the separating punch.

8. The current breaker according to claim 1, wherein the fuse part is formed in one piece with the busbar.

9. The current breaker according to claim 8, wherein the fuse part is formed by the break points.

10. The current breaker according to claim 8, wherein the busbar has two break points, the fuse part is formed by a weakened region between the two break points, and the conductors are connected to the busbar between the break points on both sides of the fuse part.

11. The current breaker according to claim 8, wherein the busbar is of substantially uniform cross-section outside the break point.

12. The current breaker according to claim 1, wherein at least one of the conductors has a cross section of at most 0.1 mm.sup.2.

13. The current breaker according to claim 1, wherein at least one of the conductors is mechanically cut when the current breaker is triggered.

14. The current breaker according to claim 13, wherein at least one conductor is in a movement path of the separating punch.

15. The current breaker according to claim 14, wherein the at least one conductor is in the form of a loop.

16. The current breaker according to claim 13, wherein at least one conductor extends through the separating punch.

17. The current breaker according to claim 3, wherein at least one conductor extends through the drive piston and is mechanically cut when the current breaker is triggered.

18. The current breaker according claim 7, wherein at least one conductor extends through the extinguishing agent and is cut when the circuit breaker is triggered.

19. The current breaker according to claim 4, wherein the extinguishing agent is at least partially a silicon oil or grease.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be explained in more detail with reference to the accompanying drawings, in which:

[0021] FIG. 1 is a longitudinal section of a current breaker according to the invention taken along the line B-B of FIG. 2, and

[0022] FIG. 2 shows the same in a view from below when the lower housing part is removed.

BEST MODE FOR CARRYING OUT THE INVENTION

[0023] A current breaker 1 according to the invention has a upper housing part 20 and a lower housing part 24 between which extends a busbar 2 with bores 3a and 3b and a weakened region 4 delimited by two rows of openings forming two break points 5a and 5b. Contact pins 6a and 6b of a first igniter 7 are connected to conductors 8a and 8b, so that the igniter is electrically connected in parallel with the weakened region 4. The igniter 7 is in a separating punch 9 carrying an O-ring 11 in a groove 10 and an extinguishing agent 13 in a further groove 12. Furthermore, the separating punch 9 has an upwardly open central bore 9′, so that the pressure created by the igniter 7 can be used to move the separating punch 9.

[0024] The current breaker 1 has a second igniter 14 with contacts 15a and 15b accessible from the outside and held in a so-called 11 mm interface 16 by a retainer. The 11 mm interface 16 and retainer securely contact the second igniter 14 from the outside.

[0025] A drive piston 17 with a groove 18 holding an O-ring 19 is provided below the second igniter 14 toward the weakened region 4. The igniter 14, the drive piston 17 and the separating punch 9 are in the upper housing part 20 that is reinforced on the outside with a metallic reinforcement casing 21.

[0026] A brake element 22 is provided below the weakened region 4 in a bore 23 of the lower housing part 24. Like the upper housing part 20, the lower housing part 24 also has a metallic reinforcement casing 25. The upper housing part 20 and the lower housing part 24 are held together by the reinforcements 21 and 25 and four screws 26a-26d.

[0027] FIG. 2 shows the upper housing part 20 with busbar 2 and the holes that form both a melting region in the case of overcurrent and the mechanical break points 5a and 5b.

[0028] The illustrated current breaker has the following functionalities:

[0029] a) Active Triggering

[0030] When an ignition pulse is applied to the contacts (pins) 15a and 15b of the second igniter 14, it is triggered and drives the drive piston 17 down. Force is transmitted to the separating punch 9 to first separate the conductors 8a and 8b from the first igniter 7 and then the busbar 2 at the break points 5a and 5b formed by the holes. At the interruption points of the busbar 2, depending on the applied current intensity, electric arcs can form that are cut by movement of the separating punch 9 away from the igniter 14 and finally are extinguished by contact with the extinguishing agent 13. During movement of the separating punch 9, the brake element 22 is compressed (not shown here) so it can insulate the weakened region of the busbar 2 in order to avoid current flow through the brake element. In the case of this so-called “commanded triggering,” first the connection to the first igniter 7 is interrupted and only subsequently is the busbar 2 cut. As a result, flow of the current to the circuit of the first igniter 7 is reliably prevented.

[0031] b) Passive Triggering:

[0032] When current flows through the busbar 2, the weakened region 4 and the two break points 5a and 5b weakened by the holes are heated. If the heating becomes too large, the busbar 2 melts like a fuse part in the weakened region. Current then is fed into the first igniter 7 and fires it, creating upward pressure in the bore 9′ toward the drive piston 17. The resulting pressure is confined in a chamber formed by the drive piston 17, the separating punch 9 and the inner wall of the upper housing part 20, and drives the separating punch 9 to first separate the conductors 8a and 8b that connect the contact pins 6a and 6b of the first igniter 7 to the busbar 2 to both sides of the weakened region 4, as a result of which it is irrelevant whether or not the igniter has a certain conductivity after the triggering. Subsequently, the separating punch 9 moves farther down (away from the second igniter 14) and pushes the residues of the weakened region 4 of the busbar 2 downward. The weak arc that is at best produced is extinguished by contact with the extinguishing agent 13 in a manner analogous to the commanded triggering.

[0033] In principle, two variants are possible for passive triggering. The break point or points in the busbar 2 can coincide with the so-called “active site”, i.e. the region that melts and burns analogously to a fuse part, as illustrated in FIG. 2, or spaced therefrom.

[0034] The embodiment in FIG. 1 shows an embodiment with two break points 5a and 5b that are cut through during commanded triggering. However, the principle can be adapted for systems with only one break point. Clearly, tapping the voltage for the passive triggering takes place at the two sides of the “active site” for the passive triggering that can coincide with the mechanical break point, but does not have to. The separation of the conductors 8a and 8b for the passive triggering, can also be effected by passing the conductors 8a and 8b through one of the pistons or through the intermediate space between the two pistons in order to prevent a current path through the first igniter 7 during the commanded triggering.

[0035] Common to all concepts is that the separation of the conductors 8a and 8b for the passive triggering with commanded triggering can also be realized in a particularly advantageous manner by separating a loop through the separating punch 9.