CIRCUIT INTERRUPTER, CONDUCTOR THEREFOR AND METHOD OF MAKING SAME

Abstract

The aim of the invention is to produce a conductor (14) for a circuit breaker (11), said conductor having a printed circuit board (14c) to be separated between two conductor ends and additionally having a conductor encapsulation (15) that has a cavity (20) in which the printed circuit board (14c) is located. This is achieved in that a plastic melt is injected, via at least one gate (21), into an injection mold, in which the conductor (14) is located. According to the invention, the gating process (21) is carried out from out of the cavity (20), through which the conductor passes, wherein the plastic melt flows from the gate (21) to the actual conductor encapsulation (15) through a runner (22; 24a-24d; 26a, 26b). In the process, the gate (21) can remain in the completed circuit breaker (11).

Claims

1. A method of making a conductor for a circuit interrupter having a circuit board to be severed between two conductor ends, the conductor having a conductor overmolding forming a cavity holding the circuit board, molten plastic being injected through a sprue of an injection mold holding the conductor, wherein the sprue extends from the cavity holding the conductor, the molten plastic flowing from the sprue through a sprue manifold to the conductor overmolding.

2. The method according to claim 1, wherein the sprue together with the sprue manifold are separated from the conductor overmolding before they are installed in the housing of the current interrupter.

3. The method according to claim 2, wherein the sprue is severed the conductor overmolding.

4. The method according to claim 3, wherein the sprue is separated or punched out by at least one ejector.

5. The method according to claim 2, wherein the sprue together with the sprue manifold are removed by twisting the sprue.

6. The method according to claim 2, wherein the conductor has a hole and the sprue is separated by a punch that is passed through this hole.

7. A conductor with conductor overmolding, manufactured according to claim 1, wherein the conductor overmolding has a cavity, in which a printed circuit board is located, and a sprue, and the sprue together with the sprue manifold are in the cavity of the conductor overmolding.

8. The conductor according to claim 7, wherein the sprue manifold is at least partially umbrella-shaped.

9. The conductor according to claim 7, wherein between the sprue and the sprue manifold there is filling-space plastic that extends further in the direction of the wall of the cavity than the sprue.

10. The conductor according to claim 7, wherein the circuit board has a hole and at least a part of the sprue extends through this hole and preferably has a larger cross-section past the hole than the cross-section of the hole.

11. The conductor according to claim 7, wherein the sprue manifold is formed by a plurality of passages whose connection to the conductor overmolding takes place in the lateral edge region of the conductor.

12. The conductor according to claim 11, wherein the connection of the passages to the conductor overmolding extends to predetermined fracture lines of the conductor.

13. The conductor according to claim 11, characterized wherein the passages are located opposite one another in pairs relative to the axis of the cavity of the conductor overmolding.

14. The conductor according to claim 7, wherein the connection of the sprue manifold to the conductor overmolding is in a plane spaced from the conductor, preferably by a distance of at least 1 mm, particularly preferably by at least 2 mm.

15. The conductor according to claim 14, wherein the sprue manifold has two manifold passages that are perpendicular to a longitudinal axis of the conductor.

16. The conductor according to claim 7, wherein the conductor has a reduction in cross-section in the region where it enters the conductor overmolding.

17. The conductor according to claim 16, wherein the cross-sectional reduction is formed by laterally open notches on the conductor.

18. A circuit interrupter having a housing, a pyrotechnic detonator and a separating piston for separating a circuit board from a conductor, wherein the conductor is formed with conductor overmolding according to claim 7.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0024] The present invention is described in more detail with reference to the accompanying drawings. Therein:

[0025] FIG. 1A shows a pyrotechnic circuit interrupter with a lower housing part, an upper housing part and a conductor overmolding, with a sprue and a shield-shaped sprue manifold;

[0026] FIG. 1B shows the conductor overmolding from below;

[0027] FIG. 1C is a plan view of the conductor;

[0028] FIG. 1D a section along the line 1d-1d of FIG. 1B;

[0029] FIG. 1E a section along the line Ie-Ie of FIG. 1B;

[0030] FIG. 2A shows another embodiment of a conductor overmolding from below, with four diagonal manifold passages;

[0031] FIG. 2B is a section along line IIb-IIb of FIG. 2A;

[0032] FIGS. 3A and 3B are views similar to FIGS. 2A and 2B, but with a filling space between the sprue and manifold passages;

[0033] FIGS. 4A and 4B are views similar to FIGS. 3A and 3B, but with a conductor with a central hole;

[0034] FIG. 5A shows another embodiment of a conductor overmolding from below, with two manifold passages extending normal to the longitudinal axis;

[0035] FIG. 5B is a section along the line Vb-Vb of FIG. 5A;

[0036] FIG. 5C is a section along the line Vc-Vc of FIG. 5A; and

[0037] FIGS. 6A to 6C are views similar to FIGS. 5A to 5C, but with gates below the conductor plane and with a conductor with a central hole.

WAY(S) TO CARRY OUT THE INVENTION

[0038] FIG. 1A shows a pyrotechnic circuit interrupter 11 having a housing comprised of a lower housing part 12, an upper housing part 13 and therebetween a conductor 14 set in an intermediate injection-molded part 15. The parts are held together by four screws 16.

[0039] The conductor overmolding 15 is formed by placing the conductor 14 in an injection mold and then injection molding the conductor overmolding 15 around it. This has the advantage that there can be no gap between the conductor overmolding 15 and the conductor 14 due to the manufacturing process; instead the conductor overmolding 15 lies tightly against the conductor 14 even without any additional seals. To seal the housing, it is therefore sufficient to seal the lower housing part 12 and the upper housing part 13 against the conductor overmolding 15 that is relatively easy to do because injection-molded parts do not have any sharp edges, unlike the conductor 14 produced by stamping. For example, a groove 12a can be provided into which a O-ring is inserted.

[0040] The conductor overmolding 15 has a central cavity 20. A separating piston 19 is in it between the conductor 14 and the upper housing part 13. A pyrotechnic igniter 17 is in the upper housing part 13. It can be connected to an electronic circuit by a plug 18. When the electronic circuit generates an ignition signal, the igniter 17 abruptly generates a superatmospheric pressure that presses the separating piston 19 against the conductor 14 and thus breaks out a middle section of the conductor 14, referred to below as a circuit board 14c.

[0041] In order to facilitate this, the conductor 14 (see also FIG. 1C) has on both sides of the circuit board 14c predetermined fracture lines 14b that are in the form of grooves. In addition, recesses or notches 14d are provided at the end of these grooves so that not only the thickness of the conductor 14 is reduced in the area of the predetermined fracture lines 14b, but also its width. In this way, the board 14c can be easily punched out by the separating piston 19 (see FIG. 1a). The conductor 14 (see also FIG. 1C) has holes 14a at its ends so that a cable can be screwed onto each end. As long as the conductor 14 is intact, the two screwed-on cables are electrically connected to each other. As soon as the circuit board 14c is punched out, they are electrically disconnected from each other. In this way, very high voltages (e.g. 500 V) can be disconnected, even if very high currents (e.g. 2000 A) are flowing.

[0042] For the simplest possible manufacture of the conductor overmolding 15, a central sprue 21 (see also FIGS. 1B, 1D and 1E) is provided, formed by the liquid plastic fed into the injection mold. It flares to the outside via an umbrella-shaped manifold formation 22, where it forms the actual conductor overmolding 15. The transition between the sprue manifold formation 22 and the actual conductor overmolding 15 is referred to below as a gate 23. The sprue 21 together with the sprue manifold 22 can be severed at the gate 23 as will be explained below.

[0043] According to a preferred embodiment of the invention, the sprue 21 remains in the circuit interrupter 11. If a corresponding recess 31 is provided in the lower housing part 12 (see FIG. 1A), the combination of sprue 21 and recess 31 acts as a guide for the board 14c when it is moved down by the separating piston 19, and with appropriately selected diameters a relatively gentle braking of the board 14c can also be achieved as a result.

[0044] As can be seen in particular from FIG. 1D, the plastic of the conductor overmolding 15 fills the grooves of the predetermined fracture lines 14b on the side facing the sprue 21, thereby stabilizing the conductor 14.

[0045] The embodiment shown in FIGS. 2A and 2B differs from the embodiment described above in that four distribution passages 24a to 24d are provided instead of the shield-shaped sprue manifold 22. These distribution passages 24a to 24d each form an angle of around 45 with the longitudinal axis of the conductor 14, so that they fill the recesses 14d (see FIG. 1C) of the conductor 14. In this way, the gates 23 (see FIG. 2B) can be level with the conductor or circuit board 14c.

[0046] The embodiment according to FIGS. 3A and 3B differs from the embodiment according to FIGS. 2A and 2B only in that there is a filling space between the sprue 21 and the distribution passages 24a-d during injection molding, which is helpful for the uniform distribution of the plastic into the four distribution passages 24a-d. The plastic remaining there is referred to as filling-space plastic 25. It improves the connection between the sprue 21 and the board 14c.

[0047] This connection can also be stabilized by the fact that a central hole 14e (see FIG. 4B) is provided in the board 14c (see FIG. 4b) through which the plastic passes during injection molding and forms a widened head 27 on it. In this way, a form-fit connection is created between the sprue 21 and the board 14c, so that the diameter of the filling-space plastic 25 can be smaller than in the above-described embodiment according to FIGS. 3A and 3B.

[0048] FIGS. 5A to 5c show an embodiment in which two distribution passages 26a, 26b are provided. These two distribution passages 26a, 26b extend perpendicular to the longitudinal axis of the conductor 14. Since the width of the conductor 14 is smaller than the diameter of the cavity 20, the gates 23 can be located at the height of the conductor 14 or the circuit board 14c. The area 28 between the conductor 14 and the conductor overmolding 15 can be free, but it can also be filled with plastic.

[0049] However, the gates 23 can also be located below this, as shown in FIGS. 6A to 6C. This embodiment also differs from the embodiment just described in that the board 14c has a central hole 14e, as is the case in the embodiment according to FIG. 4B. Here, however, the plastic does not emerge into the area above the board 14c, so that the sprue 21 together with the filling-space plastic 25 and the distribution passages 26a, 26b can be easily severed at the gates 23 by pressing on the hole 14e from above with the piston.