EP1302960A2 - Contact arrangement for current limiting circuit breaker - Google Patents

Abstract

The contact device has a switch shaft (6) rotating about an axis (z) perpendicular to the centre plane (xy) of the switch pole within the insulating housing of the protection switch, a rotary contact bridge (10) fitting in a recess (12) of the switch shaft and extending along the centre plane, with contact pieces (14) at its diametrically opposing ends cooperating with stationary contacts (16). The contact force is provided by pairs of tension springs (18) positioned symmetrically on both sides of the centre plane and symmetrical to the rotation axis of the contact bridge, with coupling pieces (20) between the ends of each pair cooperating with extensions (28) at the opposite ends of the other pair for preventing rebound.

Description

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

From the document EP 0314540 B1 is such a contact arrangement for a Low-voltage multipole circuit breaker with insulating material known, the a means incorporated in the housing slide bearing about a fixed transverse axis having rotatable switching shaft, wherein the axis perpendicular to the longitudinal Middle plane of each pole is. Each pole comprises two connection bars fixed contacts, a rotary contact bridge extending along the median plane extends in a playful recording of the shift shaft and opposing one another Having contact pieces, which in closed position with the fixed Interacting contacts, and two mounted inside the shift shaft tension springs, which act on the contact bridge and so a specified contact pressure ensure the contact pieces on the fixed contacts, with one of the ends each tension spring cooperates with a driver element of the switching shaft. The both springs are mounted in the receptacle for the contact bridge, with the other End of each spring is attached to a fastener of the contact bridge. The two fasteners or driver elements of the two springs are with respect to an imaginary axis of rotation of the contact bridge or the fixed Transverse axis of the shift shaft diametrically opposite. This arrangement ensures the springs a free displacement of the imaginary axis of rotation of the contact bridge in Reference to the fixed transverse axis of the shift shaft and allows at the same time Moment of force for uniform distribution of the contact pressure and an elastic Positioning of the contact bridge with two translational degrees of freedom, wherein the Contact bridge due to the self-centering effect of the springs on the mid-plane is held in an equilibrium position. The connecting rails with the fixed ones Contacts are looped so that when they come from one Short-circuit current to be flowed through, a contact bridge against the Force effect of the tension springs in the direction of a repelling position repulsive, electrodynamic Generate forces. In such a contact arrangement is the Danger of being thrown up by electrodynamic forces in the event of a short circuit movable contact bridge will damage their stop or fall back too fast to unwanted re-ignitions of arcing and / or contact welding can lead.

From the publication EP 0560697B1 is a low-voltage circuit breaker with a contact arrangement per pole known on both sides of the contact bridge, the extends in the median plane of the pole, with two symmetrically arranged Pair of tension springs is equipped. The springs are symmetrical on both Arranged sides of the axis of rotation of the contact bridge and have each one on the contact bridge stored end on. For braking and, if necessary, holding the electrodynamically repelled from the fixed contacts contact bridge is an opposite end of said springs on the ends respectively arranged slidably in a notch in the shift shaft, mounted as a transverse axis rod and has the contact bridge symmetrical to its axis of rotation on a pair of cams, which are designed so that they in the end portion of the repulsion stroke of the contact bridge with one of the rods cooperate to decelerate the movement of the contact bridge. The bars are limited slidably mounted in the notches, wherein the diametrically opposite Notches approximately along the line of action of the associated springs run. The springs ensure elastic positioning of the contact bridge in the recess of the switching shaft and thereby define a fictitious axis of rotation the contact bridge with respect to the switching shaft. The profile of the opposite the moving Contact pieces arranged control cams causes a shift of Rods in the notch and one of the pivoting movement of the contact bridge in Direction of the repulsion position corresponding continuous tension of the springs with a storage of energy in the springs. The profile of the cams can so be interpreted that the contact bridge locked in the repelling position; the rotatably mounted switching shaft by an actuating mechanism of the circuit breaker is actuated and the opening stroke of the contact bridge is limited so that the rotation of the switching shaft during the opening movement lifting the rods caused by the cams. During the pivoting movement of the contact bridge in the direction of the repulsion position, the line of action of each spring shifts and shortens doing the lever arm, whereby the force exerted by the springs on the contact bridge Resetting force moment is reduced. A disadvantage of this contact arrangement are the additional requirement of the rods to be stored and the inadequate Braking effect at high repulsive forces due to the low friction surfaces and Friction coefficient between the steel bars and the contact bridge Copper.

In a contact arrangement according to document EP-0978858-A2 grab four for the Contact pressure responsible tension springs between notches of the rotary contact bridge and on the switching shafts hinged tabs that can pivot in the way that the electrodynamically spin-coated contact bridge does not become independent again can fall back into the closed position. In a contact arrangement according to WO-9962092-A1 uses four tension springs responsible for the contact pressure between four bars. Two of the rods are stored in recordings of the selector shaft and directly engage the rotary contact bridge. The other two rods are slidably guided in slots of the shift shaft and engage in articulated with the Contact bridge connected tabs, which also cause the electrodynamic spun contact bridge not again independently in the closed Position can fall behind. The disadvantage of these two solutions is that on the one hand Costly and production-consuming with the switching shaft to be connected tabs required and that on the other hand by the forced detention of the contact bridge in the spin-on position, equipped with such contact arrangements Circuit breaker is not suitable for selective switch arrangements.

The object of the invention is therefore in a simplified contact arrangement with improved delay behavior of the electrodynamically spin-coated rotary contact bridge.

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.

Due to the non-positive operative connection between a connecting piece to the first ends of the respective one, designed as a U-shaped double tension spring tension spring pair and extensions of resilient elements is the electrodynamically repelled Contact bridge slowed or inhibited in its movement. By braking the accelerated contact bridge will overall delay in the Way achieves that a relapse of the contact bridge in the closed position in time before the final opening of the contact arrangement by triggering protective organs is prevented. The inhibition function is due to structural design and / or Dimensioning of the extensions and / or connecting elements in the sense influenced, that it affects the falling back into the on position more than that Transition into the repulsion position. When falling back the electrodynamically repelled Contact bridge in the direction of closed position acts as described above non-positive connection between the connectors and the extensions inhibiting on the pushed back from the end stop and by the spring force accelerated contact bridge. The proposed contact arrangement required for Effect of said braking or inhibiting effect no technologically complex to be produced and fastened parts. Equipped with such contact arrangements Circuit breakers are suitable for use with current-limiting circuit breakers, the occurrence of an excessively high current, in particular a Short circuit current, in conjunction with triggering protective organs either themselves switch off or within a switch assembly in terms of their short-circuit current carrying capacity selectively staggered circuit breakers by another Circuit breaker to be disconnected from the short-circuit current.

An advantageous inhibition behavior for the contact bridge is obtained when using constructive design and / or dimensioning of the extensions and / or the connecting pieces one between closed position and repelling position or in reverse Direction to be overcome maximum force is present. One to achieve An alternating development of force advantageous development consists in the step-like Training the extensions. The step-like design can be a snap connection at the end of the repulsion movement between the connectors and the extensions are further developed, whereby the spin-on contact bridge is arrested after reaching their repulsion position until they reach the final Opening the contact arrangement by triggering protective devices of the circuit breaker is released from this detent position.

Advantageously, the tension springs are stored with the connecting pieces in at the contact bridge trained first notches.

An advantageous development of the invention is that the tension spring pairs equipped at their second, free ends with the extensions and preferably are supported by a steel pin in the shift shaft.

An alternative development of the invention is that the extensions are formed on additional springs, which preferably together in a U-shaped configuration with the second ends of the Zugfederpaare about ösenartige training are supported by steel pins in the shift shaft.

The extension pieces preferably engage under the transverse axis the connectors, however, the reverse arrangement is possible.

To ensure safe movement of the contact bridge this is with a Long hole provided by the one extending in the transverse axis of the shift shaft fixed bearing axis is guided. Due to the polweise composition of Switching shafts from polweise associated switching shaft segments is the contact arrangement suitable for modular circuit breakers.

Fig. 1:

eine perspektivisch dargestellte Ausführungsform der erfindungsgemäßen Kontaktanordnung in Einschaltstellung;

Fig. 2 bis 3:

die beweglichen Teile der Kontaktanordnung gemäß Fig. 1 in Einschaltstellung, und zwar Fig. 2 von vorn, demgegenüber Fig. 3 von links und Fig. 4 im Schnitt A-A;

Fig. 5 bis 7:

die beweglichen Teile der Kontaktanordnung gemäß Fig. 1 im Verlauf der elektrodynamischen Abstoßung, und zwar Fig. 5 von vorn, demgegenüber Fig. 6 von links und Fig. 7 im Schnitt B-B;

Fig. 8 bis 10:

die beweglichen Teile der Kontaktanordnung gemäß Fig. 1 am Ende der elektrodynamischen Abstoßung, und zwar Fig. 8 von vorn, demgegenüber Fig. 9 von links und Fig. 10 im Schnitt C-C;

Fig. 11 bis 14:

verschiedene Ausführungen von Zugfederpaaren in unterschiedlichen Darstellungen;

Fig. 15, 16:

eine Ausführungsform einer Zusatzfeder in unterschiedlichen Darstellungen.

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

Fig. 1:

a perspective illustrated embodiment of the contact arrangement according to the invention in closed position;

2 to 3:

1 in closed position, namely Fig. 2 from the front, in contrast, Fig. 3 from the left and Fig. 4 in section AA;

5 to 7:

in the course of the electrodynamic repulsion, namely FIG. 5 from the front, in contrast FIG. 6 from the left and FIG. 7 in section BB;

8 to 10:

1 at the end of the electrodynamic repulsion, namely FIG. 8 from the front, in contrast FIG. 9 from the left and FIG. 10 in section CC;

11 to 14:

various designs of tension spring pairs in different representations;

Fig. 15, 16:

an embodiment of an additional spring in different representations.

The contact arrangement 2 according to the invention according to FIG. 1 is not for one pole further provided multi-pole circuit breaker provided. The circuit breaker conventionally comprises an insulating material housing, actuatable by a drive Switch lock, feeding and outgoing connection elements as well as tripping devices for overload and short circuit. In the case is a fixed one Transverse axis z a shift shaft 6 rotatably mounted, wherein the transverse axis z is perpendicular runs to the median plane xy of the pole. The switching shaft 6 is assigned from polweise Schaltwellensegmenten assembled. A rotary contact bridge 10 extends along the median plane xy in a play-like receptacle 12 of the Switching shaft 6 and has opposing contact pieces 14 which in Switching position with fixed contacts 16 cooperate. The contact bridge 10 has a slot 11 (see, for example, Fig. 4) with which it is fixed on a fixed, in the transverse axis z of the switching shaft 6 extending bearing axis 7 is mounted. In the receptacle 12 are on both sides of the contact bridge 10 and the median plane xy arranged two tension springs 18, which has the required contact force between the Apply contact pieces 14 and the fixed contacts 16.

The tension springs 18 have a mounted on the contact bridge 10 first end 19 and a mounted on the shift shaft 6 second end 21. On each side of the contact bridge10 are the first ends 19 with respect to the axis of rotation of the contact bridge 10 and the second ends 21 of the respective tension springs 18 with respect to Transverse axis z of the shift shaft 6 diametrically opposite. The tension springs 18 are symmetrical arranged in relation to the median plane xy. Two each on opposite Side of the median plane xy located first ends 19 are integrally across transverse Connectors 20 connected, and two each on opposite Side of the median plane xy located second ends 21 are in transverse steel pins 23 hooked. The connecting pieces 20 form with the associated pairs the tension springs 18 U-shaped double tension springs and are non-positively in first notches 25 of the contact bridge 10. The steel pins 23 are in corresponding second notches 27 of the shift shaft 6. With each of the two fixed contacts 16, a loop-shaped connecting rail 24 is connected. This loop shape causes the flow of a short-circuit current, the contact bridge 10 through electrodynamic forces against the force of the tension springs 18 from the closed position 1 to 4 in the direction of a repelling position shown in FIG. 8 to 10 is pushed back.

The contact arrangement 2 according to the invention continues to be resilient in the switching shaft 6 attached elements provided in the embodiment of FIGS. 1 to 10 are identical to the second ends 21 of the tension springs 18 and each with a simple Winding and a subsequent free-running extension 28 are equipped. By the two loop-shaped ends 21 each two with respect the median plane xy opposite tension springs 18 each one of the Steel pins 23. The two extensions 28 each of a double tension spring extend to to the connector 20 of the other double tension spring and reach under the respective connector 20. In electrodynamically effected repulsion of the contact bridge 10 as shown in FIGS. 5 to 10 rub the connecting pieces 20 and the extensions 29 with increasing repulsion on each other. This friction annihilates only in part the kinetic energy of the electrodynamic repulsion high accelerated contact bridge 10 so that their transition from that shown in Fig. 1 to 4 Switching on the transition position shown in Fig. 5 to 7 to the 8 to 10 end position with a slight delay takes place. After a short stay of the contact bridge 10 in the end position, this falls with only noticeable delay back. The increasingly acting on the contact bridge 10 Return force with progressive repulsion movement is essentially due to the Rotation of the spring body of the tension springs 18 determines the bearing axis 7 and limited at the same time the rotation of the spring body. The repulsion movement of the contact bridge 10th causes an increase in the distance between the spring ends 19 and 21. Nach the impact on the insulating housing of the circuit breaker and a reverse Acceleration in the direction switch position, the contact bridge 10 due the frictional interaction of the extension pieces 28 with the Connectors 20 braked again and falls with considerable delay back. The bearing axis 7 limits the rotation and also prevents a flat Collision of the spring body of the tension springs 18 and allows a relatively soft Force increase with a high energy storage to hit the contact bridge 10th

In Figs. 11 and 12, the pair is symmetrical about both sides of the median plane xy located tension springs 18 shown in FIG. 1 to 10 in detail. The two springs 18 are U-shaped at their first ends 19 via the connecting piece 20 merged to the double tension spring and point to its loop-shaped wound second ends 21, the extensions 28. The extensions 28 are provided opposite the longitudinal axis of the tension springs 18 with a bending angle, which is dimensioned in such a way that with increasing electrodynamic repulsion the contact bridge 10 the power requirement from the electrodynamic acceleration and the relapse acceleration to overcome the force between the connector 20 of a pair of tension springs and the extensions 28 of the other tension spring pair increases.

In Fig. 13 and 14, a slightly different designed pair of tension springs 18 is shown. This also formed as a U-shaped double tension spring tension spring distinguishes from the above-described tension spring pair essentially by with a gradation 33 provided embodiment of their extensions 29 and through the arcuate formation of their second ends 22. The parallel to the median plane xy extending gradations 33 of the step-like extensions 29 of a tension spring pair can in the interaction of the connector 20 of the other Zugfederpaares with in the course of electrodynamic repulsion of the contact bridge 10 cause two things: First, by the design of the turn angle and the gradation 33 the initially increasing counterforce at the end of the repulsion movement markedly attenuated by the gradation 33, so that by the Decreasing braking effect a slightly extended residence time in the end of the Repulsion occurs. On the other hand, as in the case shown in Fig. 13, the gradation 33 are dimensioned such that in the end position of the ejected Contact bridge 10, the connecting piece 20 of each one spring pair with the Extensions 29 of the other spring pair in the region of their gradation 33rd a latching connection is received, which is only a conscious return of the contact bridge 10 allowed from this end position. Each pair of tension springs is stored under the influence the tensile force of the tension springs 18 with the second ends 22 arcuate to one each the steel pins 23 shown in Fig. 1.

FIGS. 15 and 16 show that, as an alternative to those described above Embodiments each two extensions 28 part of another element as. Each designed as a U-shaped torsion spring auxiliary spring 30 is with her tortuous outer thighs on one of the steel pins 23 between the second To store ends 21 of the tension springs 18 of each one Zugfederpaares. To the outer legs are each equipped with an extension 28. At this Of course, the extensions of the tension springs 18 are omitted extended middle part 31 of the auxiliary spring 30 is supported in the switching shaft 6 in the Assume that the extensions 28 spring force against the connector 20 of the other tension spring pair is present.

The present invention is not limited to the above-described embodiments but also includes all the same in the context of the invention Embodiments. The invention may be carried out, for example, in the manner be that the extensions 28 or 29 with a directed to the transverse axis z Component of the spring force on the associated connectors 20 engage. Also, the tension springs 18 in the context of the inventive concept by Replace compression springs or torsion springs, suitably between the contact bridge 10 and the shift shaft 6 are arranged.

Claims (14)

Contact arrangement for at least single-pole, current-limiting circuit breaker in the low-voltage range with an insulating housing, comprising a switching shaft (6) rotatably mounted in the insulating housing about a fixed transverse axis (z), the transverse axis (z) being perpendicular to the median plane (xy) of the pole, a rotary contact bridge (10) which extends along the median plane (xy) in a play-loaded receptacle (12) of the switching shaft (6) and diametrically opposed contact pieces (14) which cooperate in the closed position with fixed contacts (16), in the interior of the switching shaft (6) arranged contact force-tension springs (18) each having a on the contact bridge (10) arranged first end (19) and one on the switching shaft (6) arranged second end (21, 22), wherein the first ends (19) are diametrically opposed with respect to the axis of rotation of the contact bridge (10) and the second ends (21; 22) are diametrically opposed with respect to the transverse axis (z), and two with one of the fixed contacts (16) connected to connecting rails (24), the flow of very high currents in cooperation with the contact bridge (10) against the force of the tension springs (18) the contact bridge (10) in the direction of a repelling repelling, electrodynamic Generate forces, characterized, in that the tension springs (18) are in each case arranged symmetrically in pairs symmetrically with respect to both sides of the median plane (xy) and said pairs of tension springs (18) with respect to the axis of rotation of the contact bridge (10), that the first ends (19) of each of said pairs of tension springs (18) are integrally connected to each other via transverse connecting pieces (20) and in that elements (18; 30) resiliently arranged in the switching shaft (6) are provided with extensions (28; 29) which extend to the connecting pieces (20) and are constructed and arranged such that between them and the connecting pieces (20; ) occur in the transition of the contact bridge (10) of the closed position in the repelling position and in the opposite direction in addition to overcoming forces. Contact arrangement according to one of the preceding claims, characterized in that between power-on position and repelling position or vice versa, a maximum force is to be overcome by the contact bridge (10). Contact arrangement according to the preceding claim, characterized in that the extensions (29) are step-like. Contact arrangement according to the preceding claim, characterized in that after reaching the repelling position, the connecting pieces (20) with the associated extensions (29) enter into a force-dependent, detachable latching connection. Contact arrangement according to one of the preceding claims, characterized in that the connecting pieces (20) in formed on the contact bridge (10) first notches (25) store. Contact arrangement according to one of Claims 1 to 5, characterized in that the extensions (28; 29) adjoin the second ends (21; 22) of the said pairs of tension springs (18) and extend up to the connecting piece (20) of the each other pairs of tension springs (18) extend. Contact arrangement according to Claim 6, characterized in that the second ends (21) of said pairs of tension springs (18) are looped around a respective steel pin (23) which in turn bears in second notches (27) of the control shaft (6). Contact arrangement according to Claim 6, characterized in that the second ends (22) bear in an arc-shaped manner on a respective steel pin (23), which in turn supports in second notches (27) of the switching shaft (6). Contact arrangement according to one of claims 1 to 5, characterized in that the extensions (28) are formed on additional springs (30). Contact arrangement according to the preceding claim, characterized in that the second ends (21; 22) of said pairs of tension springs (18) are wound around one or bent on a respective steel pin (23), which in turn is inserted in second notches (27) of the control shaft (6) stores, and that around the steel pins (23) each formed as a U-shaped torsion springs Zugsatzfedern (30) with its outer legs looped wound, the outer legs are each equipped with an extension (28) and also extended Central part (31) of the additional springs (30) in the switching shaft (6) is supported. Contact arrangement according to one of Claims 1 to 10, characterized in that the extensions (28; 29) engage under the connecting pieces (20) with a spring force component directed away from the transverse axis (z). Contact arrangement according to one of claims 1 to 10, characterized in that the extensions (28; 29) engage with a spring force component directed towards the transverse axis (z) via the connecting pieces (20) Contact arrangement according to one of the preceding claims, characterized in that the contact bridge (10) with a slot (11) on a fixed, in the transverse axis (z) of the switching shaft (6) extending bearing axis (7) is mounted. Contact arrangement according to one of the preceding claims, characterized in that the switching shaft (6) consists of polweise associated switching shaft segments.

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