EP1513178A2 - Contact arrangement for current limiting circuit breaker - Google Patents

Abstract

In the mid-plane of each pole, a rotary contact bridge (16) having diametrically opposing contact pieces (24) which cooperate with fixed contacts (26), extends in shaft (6,8) mounted in an insulating housing (2). Two locking cams (44) are mounted in the housing on the other side to the rotary axis.

Description

The invention relates to a contact arrangement for current-limiting circuit breaker in Low-voltage range according to the preamble of claim 1, in particular for current-limiting circuit breakers.

From DE 101 50 550 C1 is a contact arrangement for current-limiting circuit breakers known in which a double interrupting rotary contact bridge over four contact pressure tension springs arranged in pairs symmetrically on both sides of the contact bridge is connected to a switching shaft. To delay the delay act from fixed contacts electrodynamically repelled contact bridge Connecting pieces between the first ends of each one Zugfederpaares against extensions at the second ends of the other pair of tension springs. To achieve a changing force curve, the extensions are step-like formed, resulting in a latching connection at the end of the repulsion movement between leads the connectors and the extensions, causing the spin-on Contact bridge is held on reaching their repulsion position until they at the final opening of the contact arrangement by triggering protective organs This detent position is solved. The one-piece pairs of tension springs store with their connecting pieces in notches of the contact bridge and with the extensions equipped ends via steel pins in notches of the shift shaft. To guarantee safe movements of the contact bridge this is provided with a slot, by the one in the transverse axis of the shift shaft extending fixed bearing axis is guided. Due to the polweise composition of the switching shafts Polweise associated switching shaft segments is the contact arrangement for modular Compatible circuit breaker suitable. The disadvantage is the complicated trained and thus expensive as well as expensive to mount tension spring pairs.

From DE 100 61 394 A1 is considered to be the closest prior art further contact arrangement for a current-limiting circuit breaker known, in which a rotary contact bridge in a switching shaft via two contact pressure springs is floating. The contact springs are as double torsion springs formed, the pair-symmetrically arranged on both sides of the contact bridge are, with their turns loosely around one formed at the contact bridge, Bear in the rotational symmetry axis extending bearing pin, with parallel to the Bearing extending, connecting the torsion spring halves connecting pieces act on the front side of the contact bridge and with their outer ends on the Support selector shaft. In this contact arrangement are neither means for release delay still for keeping open at short circuit currents from the fixed ones Contacts provided electrodynamically repelled contact bridge.

The object of the invention therefore consists in a technologically improved current-limiting Contact arrangement with retained electro-dynamic contact opening.

Based on a contact arrangement of the type mentioned above, the task according to the invention by the characterizing features of the independent claim solved, while the dependent claims advantageous developments can be found in the invention.

The individual, supporting a bearing pin winding contact pressure torsion springs each between a spring-loaded locking cams and a Arm of the rotary contact bridge. On the one hand, this makes the required contact pressure generated. On the other hand, the occurrence of a short-circuit current of the acting on the rotary contact bridge electrodynamic opening force by appropriate Head-shaped shaping of the locking cam a variable torque opposed. This by the combination of torsion springs and spring-loaded Cams generated torque causes on the one hand an initial Delay of the repulsion movement and on the other hand, the transition of the rotary contact bridge in a latching repulsion position. By usual measures for material selection and / or surface structuring of the contacting surfaces of the second spring ends and the locking cam can their frictional resistance and thus the delay of the repulsion movement of the contact bridge varies within a wide range become.

In an advantageous embodiment, the locking cams are mounted longitudinally displaceable and provided with convex top surfaces. In an electrodynamic repulsion of Rotary contact bridge, the second spring ends of the torsion springs slide over the convex Head surfaces and move the locking cams against their cam springs. Of the Electrodynamically acted contact bridge is initially an increasing Spring force opposite. If the second spring ends, however, the Can overcome the apex line or apex of the convex head surfaces the locking cams come back through the action of their cam springs in the direction of their Move back starting position. The decreasing counterforce causes the Contact bridge in a stable repulsion position passes, from which they only at the final Opening the contact arrangement is released as a result of triggering protective organs. For at the convex top surfaces of the spring-loaded locking cams adjacent second spring ends of the torsion springs exist on both sides of the Vertex line or crest surface stable positions, on the one hand the closed position and on the other hand correspond to the repelling position of the contact bridge. Conveniently, are the convex top surfaces as two merging bevels formed, wherein in the stable positions, the second spring ends on one of the slopes issue.

Round curved second spring ends and provided for this in the locking cams Sliding grooves are advantageous for safe operation of the contact arrangement. In the insulating housing recessed damping elements - for example, made of elastic Material - serve to capture the kinetic energy of the electrodynamically accelerated Contact bridge.

In an advantageous embodiment, the half-wave polweise consists of two halves, store in the insulating housing and between those of the bearing pin with the on it playful - usually via a slot - overlapping rotary contact bridge is held.

For stability reasons are a metallic bearing pin and reasons of dielectric strength pushed on insulating bushings for the spring coils of advantage.

Figur 1:

eine erfindungsgemäße Kontaktanordnung für einen Schaltpol bei geöffnetem Isoliergehäuse;

Figur 2:

ähnlich Fig. 1, allerdings mit teilweise entfernten oder weggebrochenen Einzelteilen;

Figur 3:

Einzelheiten der Kontaktanordnung in verschiedenen Ansichten;

Figur 4:

die Kontaktanordnung in verschieden Schaltstellungen;

Figur 5:

Einzelheiten aus Fig. 2.

Further details and advantages of the invention will become apparent from the following, explained with reference to figures embodiment. Show it

FIG. 1:

a contact arrangement according to the invention for a switching pole with the insulating housing open;

FIG. 2:

similar to Figure 1, but with parts partially removed or broken away.

FIG. 3:

Details of the contact arrangement in different views;

FIG. 4:

the contact arrangement in different switching positions;

FIG. 5:

Details of Fig. 2.

The contact arrangement is made of an insulating housing consisting of two half-shells 2, from which in Fig. 1, 2 and 4, the front half-shell is removed. In circular recesses 4 of the insulating housing 2 are two, forming a switching shaft Shift shaft halves 6 and 8 are mounted, of which in Figs. 2 and 4, the front Shift shaft half 6 and in Fig. 3 both switching shaft halves are removed. The shift shaft 6, 8 has outwardly facing driving pins 10, in which to an actuating mechanism leading actuating levers 12 engage. By the switching shaft 6, 8 a metallic bearing pin 14 is held. A rotationally symmetrical rotary contact bridge 16 with two contact arms 18 stored on a central slot 20 loosely the bearing pin 14. The contact bridge 16 extends in the median plane of the Schaltpols, which coincides with the parting plane of the insulating housing 2. The rotation axis 22 of the contact assembly falls into the bearing pin 14. At the ends of the contact arms 18 are diametrically opposed contacts 24 fixed, which in the in Fig. 1, 2, 3 and 4a shown switching position of the contact arrangement with the outside guided fixed contacts 26 are connected. Between the half-shells of Insulating housing 2 arc quenching plates 28 are fixed.

To the necessary contact pressure between the contact pieces 24 and the fixed contacts 26 is to provide the contact arrangement with two contact pressure torsion springs 30 and 32 equipped. On both sides of the contact bridge 16 are above the bearing pin 14 insulating bushes 34 on which the spring coils 36 of the torsion springs 30th and store 32 loosely. In Fig. 1, the insulating bushes 34 through the switching shaft halves 6 hidden and omitted in Fig. 3. The torsion spring 30 or 32 is connected to a first Spring end 38 mounted in each case one of the contact arms 18 and supports itself with a second spring end 40 against the top surface 42 of a hat-shaped latching cam 44 and 46, respectively. The locking cams 44 and 46 shown individually in FIG. 5 are mounted longitudinally displaceable in the insulating housing 2. Cam springs designed as compression springs 48 are supported on the one hand by the inside of the top surfaces 42 and on the other against inserted in the insulating housing 2 abutment 50 from. At the foot of the Locking cams 44 and 46 are formed outwardly bulges 52, with the in Insulated housing 2 trained stops 54 cooperate by the locking cams 44 and 46 by the force of the cam springs 48 in the figures 1 to Assume 4 starting position.

In Fig. 3 are as essential details of the contact arrangement according to the invention again the contact bridge 16, the torsion springs 30 and 32 and the locking cams 44 and 46 are shown. Referring to FIG. 2, FIG. 3a is a front view, FIG. 3b shows a representation from the left and FIG. 3c shows a representation from the rear. The second spring ends 40 are bent around, wherein the bending axis parallel to the axis of rotation 22nd runs. The arcuate second spring ends 40 are in a sliding groove 62 of the Head surfaces 42 out (Fig. 5). The top surfaces 42 have two in a blunt Angle merging bevels 58 and 60, which are parallel to the axis of rotation 22 extend.

In the closed position of the contact arrangement shown in FIG. 4a, the second take Spring ends 40 enter a first stable position by referring to those indicated in Fig. 3a Oblique 58 of the latching cam located in its initial position 44 and 46 create. The torsion springs 30 and 32 cause their first spring ends 38 the required contact pressure, with their second spring ends 40 against support the slopes 58. The angle of attack of the bevels 58 and the ratio of Spring forces between the torsion springs 38, 40 and the cam springs 48 is through customary dimensioning set so that the locking cams 44, 46 in the closed position not be displaced from their starting position.

When opening the contact assembly by the actuating mechanism over the Actuating lever 12, the breaking forces on the shift shaft 6, 8 on the Contact bridge 16, from the contact arms 18 on the first spring ends 38 of Torsion springs 30, 32 and of these on the second spring ends 40 on the slopes 58 of the locking cam 44, 46 transmitted. The force exerted by the second spring ends 40 Forces are so great in this case that by displacement of the locking cam 44th and 46 against the spring forces of their cam springs 48, the second spring ends 40th slide over the slopes 58 and then by overcoming the in Fig. 5th illustrated apex lines 56 in engagement with the adjacent slopes 60th arrive while the locking cams 44 and 46 through the cam springs 48 in their To return to the starting position. In the off position, take the contact arrangement the second spring ends 40, the position shown in Fig. 4b. By customary established Rated conditions between angle of attack of the slopes 60 and spring forces the torsion springs 30, 32 and cam springs 48 is also prevented here, that the forces exerted by the second spring ends 40 on the slopes 60 forces no longer be able to bring the locking cams 44, 46 from their original position. In the off position of the contact arrangement shown in Fig. 4b are located Accordingly, the second spring ends 40 in their second stable position.

When a short-circuit current occurs between the contact bridge 16 and the Fixed contacts 26 occur electrodynamic forces, which the contact connection disconnect and drive the contact bridge 16 in a repulsion position analogous to Fig. 4b. The exerted on the contact bridge 16 and transmitted by the torsion springs 30, 32 Repelling forces also cause the transition of the second spring ends 40 of the in Fig. 4a shown first stable position in the second stable shown in Fig. 4b Location. By the interaction of the second spring ends 40 with the slopes 60th can the contact bridge 16 does not fall back into the closed position, but is in the open position held.

In the insulating housing 2, two cylindrical damping elements 64 are further provided, to those in the event of a short circuit to restrict movement and absorb movement of kinetic energy the contact bridge 16 whose contact arms 18 strike. In order to the risk of rebound of the contact bridge 16 in the closed position as a result of very high kinetic energy when strong short-circuit currents occur avoided. When closing the contact arrangement by means of the actuating mechanism via the actuating lever 12 and the switching shaft 6, 8, the contact bridge 16 again transferred to the closed position shown in FIG. 4a, wherein the second spring ends 40 slide from the slopes 60 on the crest lines 56 and again come to rest on the slopes 58.

Claims (7)

Contact arrangement for at least single-pole current-limiting circuit breakers with the features : in the middle plane of each pole, in a control shaft (6, 8) mounted in an insulating housing (2), a rotary contact bridge (16) with diametrically opposed contact pieces (24) which cooperate in the closed position with fixed contacts (26) extends playfully on both sides of the rotary contact bridge (16) support two contact pressure torsion springs (30; 32) with their spring coils (36) loosely about a in the axis of rotation (22) of the switching shaft (6, 8) projecting bearing pin (14), wherein in each case a contact arm ( 18) of the rotary contact bridge (16) is acted upon by a first spring end (38) of one of the torsion springs (30; on opposite sides to the axis of rotation (22) are in the insulating housing (2) two spring-loaded locking cams (44; 46) mounted, take due to the spring force to the axis of rotation (22) approached starting position and with a curved head surface (42) are formed on the a second spring end (40) in each case slidably supports one of the torsion springs (30; 32) and in each case assumes a stable position in the closed position on the one hand and in the switched-off position and in the electrodynamically effected repulsion position on the other hand. Contact arrangement according to the preceding claim, characterized in that the locking cams (44, 46) are longitudinally displaceable against cam springs (48) designed as compression springs and have a convex head surface (42). Contact arrangement according to the preceding claim, characterized in that the top surfaces (42) each have two parallel to the axis of rotation (22) extending and at an obtuse angle to each other extending bevels (58; 60). Contact arrangement according to one of the preceding claims, characterized in that the second spring ends (40) are bent around perpendicular to the rotation axis (22) and guided in a sliding groove (62) of the top surfaces (42). Contact arrangement according to one of the preceding claims, characterized in that a damping element (64) is provided on the insulating housing (2) for each contact arm (18). Contact arrangement according to one of the preceding claims, characterized in that the switching shaft (6, 8) for each pole of two in the insulating housing (2) overlapping switching shaft halves (6; 8), between which the bearing pin (14) on which the rotary contact bridge ( 16) is stored with play, is inserted. Contact arrangement according to one of the preceding claims, characterized in that the spring coils (36) to above the metallic bearing pin (14) pushed Isolierbuchsen (34) store.

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