EP2680293B1 - Release mechanism - Google Patents

Description

The invention relates to a trigger mechanism for a protective switching device, which has a lockable by means of a switching mechanism moving contact, a plunger and a release lever. Furthermore, the invention relates to an electro-mechanical protection device with such a trigger mechanism.

Circuit-breakers, such as circuit breakers or circuit breakers are used in particular as switching and safety elements in electrical energy supply networks. Circuit breakers are specially designed for high currents. A circuit breaker is an overcurrent protection device in the electrical installation and is used in particular in the field of low-voltage networks. Circuit breakers and miniature circuit breakers guarantee a safe shutdown in the event of a short circuit and protect the protected consumers and systems from overload. They protect lines, for example, from damage caused by overheating as a result of too high an electrical current and are designed to switch off the circuit to be monitored automatically in the event of a short circuit or overload, thus disconnecting it from the mains.

Such protective switching devices generally have a switching contact with a fixed contact element - the so-called fixed contact - and a relatively movable contact element - the so-called moving contact - on. To pass an electric current, the moving contact makes contact with the fixed contact. To separate the current flow of the moving contact is moved away from the fixed contact. The interruption of the current flow leads at least briefly to each protective switching device to a voltage flashover between the fixed and the movable contact element, since the Distance during the separation process of the contact elements for isolation is not sufficient. If there is a gas between the two switching contacts, this is ionized by the flashover with a correspondingly high voltage difference between the contact elements, an arc being formed due to the gas discharge.

From the patent DE 10 2004 040 288 B4 a circuit breaker is known, which has a first triggering device for detecting and switching off a short circuit and a second triggering device for detecting and switching off an overload condition. Furthermore, the circuit breaker has a switching contact with a fixed contact and a movable movable contact relative thereto and a release lever which is coupled to the first triggering device and the second triggering device such that actuated when triggering the first triggering device and / or the second triggering device of the trigger lever and the switching contact is opened.

Circuit breakers or circuit breakers are therefore designed so that the arcing occurring when opening the switch contacts deleted and thus the flow of current is interrupted. For this purpose, these protective switching devices have a magnetic trip system with a coil and a relatively movable armature plunger unit, through which the current, or even a portion of the current flowing to the switch contacts, is passed. With a rapid increase of the current, for example in the case of a short circuit, the coil attracts the armature, whereby the plunger meets a release lever, whereby a switching mechanism of the protective device is released. As a result, the protective switching device is triggered and interrupted the flow of current through the switching contact pair. Magnetic releases or magnetic trip units are used in protective switching devices, for example, to prevent the fusion of current-carrying contact surfaces at higher currents To ensure a safe shutdown if a resulting arc could damage the switching device. For this purpose, short tripping times are advantageous - in particular because the range of application of the protective switching device can be limited by a too long tripping time.

In order to achieve a quick contact opening when a short circuit occurs, the dynamic forces of the short-circuit current are used on the one hand. By a suitable, substantially parallel current conduction in the region of the switching contact, a Lorenz force is generated due to the guided in parallel, in the set direction by the short-circuit current conductor, which is directed such that the parallel adjacent conductors are pressed apart. In a protective switching device, this Lorenz force causes that from a certain short-circuit current limit, the moving contact is moved away from the fixed contact. This effect is referred to as dynamic contact opening and contributes to a shortening of the response of the protective device in the event of a short circuit at.

Furthermore, in the case of a short circuit, opening of the switching contact is also effected by means of the magnetic triggering system. The coil of the magnetic release system is energized with the short-circuit current, whereby the armature is pulled into the coil. The plunger connected to the anchor is thereby moved from a rest position to a release position. To open the switching contact, the plunger strikes the release lever, which is thereby also moved. The movement of the release lever, the switching mechanism of the protective device is released, causing the coupled with the switching mechanism moving contact is moved away from the fixed contact. This means that in the case of a short circuit, the movement of the plunger is first transmitted to the release lever, which consequently triggers the switching mechanism, whereby the moving contact is moved away from the fixed contact. In this way, thus a trigger chain, consisting realized from plunger, release lever and moving contact. A trigger mechanism with such a trigger chain is for example from the DE 10 2004 040288 B4 known.

In addition, the describes DE 18 40 006 U a short-circuit release for a circuit breaker with an acting both on the locking of the switching element and on the switching element itself to its acceleration magnet system. In this case, the magnet system on two anchors, one of which acts on the latch or the knee joint to release the switching element and the second armature to the switching element to its acceleration.

Furthermore, in the DE 10 2006 037 225 A1 a switching unit with an actuatable impact anchor and a movably mounted Entklinkungs-pin which bears against the impact anchor, known. By a suitable choice of the mass of the Entklinkungs-pin and by a suitable choice of the spring force of a compression spring through which the Entklinkungs-pin can be accelerated, resulting for the Entklinkungsweg the Entklinkungs-pin a predetermined period by which the unlatching delayed with respect to the Opening the contact point takes place.

Furthermore, the describes DE 11 28 007 B a circuit breaker with short-circuit release, consisting of a trip coil and a magnetic armature acting on a Verklinkungseinrichtung formed as a bridge switching member which is connected to a coil. In this case, the coil is provided with a lug, which acts on the Verklinkungseinrichtung of the switching element.

Finally, that describes DE 10 2006 055 936 A1 a power circuit breaker, in which when a first current limit value is exceeded, initially only the movable contact element of the switching contact of the immovable contact element the switching contact is moved away but not the switch lock is actuated.

It is an object of the invention to provide a triggering mechanism and a protective switching device, which are characterized by a short trip time and ensure optimum application of force.

This object is achieved by the triggering mechanism and the protective switching device according to the independent claims. Advantageous embodiments are the subject of the dependent claims.

The triggering mechanism according to the invention for a protective switching device has a movable contact which can be locked by means of a switching mechanism, a plunger and a triggering lever. The plunger is provided both for actuating the release lever of the moving contact provided release lever as well as for actuating the moving contact itself. For this purpose, the plunger on a first active surface, which acts in a first phase of its actuation movement for unlatching the switching mechanism to a control contour of the release lever. Furthermore, the plunger has a second active surface, which acts directly on the moving contact in a second phase of its actuating movement. In this case, the moving contact between the plunger and the control contour of the release lever is arranged.

In addition, the first active surface and the second active surface of the plunger are formed in the direction of its actuating movement at different, mutually offset positions of the plunger. Due to the staggered arrangement of the two active surfaces, a time-shifted action of the plunger on the release lever or the moving contact is realized by simple means.

Plunger and release lever are components of a magnetic release system, which in case of a short circuit a Switching contact of the protective switching device, which is formed by the fixed contact and the moving contact, opens by the moving contact is moved away from the fixed contact. Due to the mechanical arrangement of the moving contact between the plunger and the control contour of the release lever, it is possible to move moving contact and fixed contact closer together, whereby a higher Lorentz force between the two, substantially parallel sections of the moving contact and the fixed contact is achieved. In this way, the effect of dynamic contact opening is significantly improved. Further, since the dynamic contact opening takes place in time before the relatively sluggish magnetic trip system, a significant reduction in the residence time of the arc occurring when opening the switch contact at the contact points can be realized. In this way, the contact erosion is reduced to fixed contact and moving contact, whereby the switching capacity, but above all the service life of the protective device are significantly improved.

Furthermore, the trigger mechanism according to the invention has no chain of action plunger trigger lever moving contact in the conventional sense. Rather, the plunger is intended to act on the one hand on its first effective area directly on the release lever. On the other hand, the plunger via its second effective area but also acts directly on the moving contact itself. In this case, it must be ensured that the plunger first strikes the release lever to effect unlatching of the switching mechanism and thus release of the locking of the moving contact, before the plunger acts on the moving contact itself to effect a direct opening of the switching contact.

In an advantageous development of the release mechanism, the moving contact has an opening through which the plunger partially engages in order to act on the control contour of the release lever. By out in the moving contact formed opening, the plunger can reach through the moving contact to act with the first effective area on the arranged behind the opening control contour of the release lever. In this way, an extremely compact design of the trigger mechanism can be realized, which is particularly advantageous for small devices, for example in low-voltage modular devices.

In a further advantageous embodiment of the trigger mechanism of the plunger is electromagnetically movable by means of a coil. With the help of the coil can be provided with appropriate design an optimal operating force for both active operations - on the release lever on the one hand and the moving contact on the other.

In a further advantageous embodiment of the trigger mechanism, the release lever is connected to release a mechanically coupled to the moving contact pawl. The use of a pawl, which is supported when closing the switch contact on the release lever, via the mechanical coupling with the moving contact allows the realization of a sufficiently high contact force between moving contact and fixed contact.

In a further advantageous development of the triggering mechanism, the moving contact with a fixed contact of the protective switching device forms a switching contact, wherein the moving contact in the case of a dynamic contact opening of the switching contact acts on the trigger lever, thereby causing a unlatching of the switching mechanism is effected. In this way, a direct unlatching of the switching mechanism is effected even in the dynamic contact opening by the movement of the Bewegkontakts due to the caused by the short-circuit current Lorentz force, ie it must not only the movement of the inertial plunger of the magnetic release system for unlatching the switching mechanism to be awaited. The switching capacity of the protective switching device is thereby further improved.

The protective switching device according to the invention has a triggering mechanism according to the invention of the type described above. With regard to the advantages of the protective switching device according to the invention, reference is made to the advantages of the triggering mechanism according to the invention.

Further advantageous embodiments and preferred developments of the invention are given in the description of the figures and in the dependent claims.

Figuren 1A und 1B

schematische Darstellungen eines Auslösemechanismus sowie eines Schutzschaltgerätes nach dem Stand der Technik;

Figuren 2A und 2B

schematische Darstellungen des erfindungsgemäßen Auslösemechanismus sowie des erfindungsgemäßen Schutzschaltgerätes.

Embodiments of the triggering mechanism and the protective switching device will be explained in more detail below with reference to the attached figures. In the figures are:

Figures 1A and 1B

schematic representations of a trigger mechanism and a protective switching device according to the prior art;

FIGS. 2A and 2B

schematic representations of the trigger mechanism according to the invention and of the protective switching device according to the invention.

In the various figures of the drawing, like parts are always provided with the same reference numerals. The description applies to all drawing figures in which the corresponding part can also be recognized.

In the Figures 1A and 1B are a tripping mechanism known in the art ( 1B ) and a corresponding protective switching device 1 ( 1A ) shown schematically. The protective switching device 1 has an electrical switching contact, consisting of a fixed contact 4 and a movable relative to moving contact 5, on. By a rotational movement of the rotatably mounted moving contact 5, this is moved away from the fixed contact 4 in the counterclockwise direction, so that the switching contact is opened. The protective switching device 1 has an actuating element 3, which is mechanically coupled via a bracket 21 with a switching mechanism of the protective switching device 1. In the presentation of the Figure 1A the actuator 3 is shown in its ON position - the switch contact is closed. Also, the moving contact 5 is mechanically coupled to the switching mechanism, so that by means of the actuating element 3, a manually initiated opening and closing of the switching contact by a corresponding movement of the moving contact 5 can be realized. About two terminals 2, the protection device 1 with an electrical line to be monitored (not shown) can be contacted electrically.

For detecting and switching off a short-circuit current, the protective switching device 1 has a magnetic release mechanism 10, which in turn has a coil 11 and a relatively movable plunger 12. The fixed contact 4 is connected via a magnetic yoke 16 to the coil 11 electrically conductive. The plunger 12 forms with an armature 13, a so-called armature plunger assembly, which is movably mounted within the bobbin 11 and when energizing the coil 11 due to the force acting on the armature 13 electromagnetic forces in a longitudinal direction L of the coil 11 is movable , In the case of a short circuit, the armature 13 is pulled in the longitudinal direction L in the bobbin 11. In this case, the plunger 12 connected to the armature 13 strikes the rotationally mounted release lever 6, which is thereby rotated about its axis of rotation D in the counterclockwise direction. As a result, on the one hand realized by means of a pawl latching of the switching mechanism over which the moving contact 5 was locked solved. Due to the movement of the release lever 6, the pawl can not support, the switching mechanism falls, driven by springs, together. By a mechanical coupling of this movement on the moving contact 5, the switching contact is torn open. Further, the actuator 2 is moved via the bracket 21 in its OFF position. Furthermore, the release lever 6, triggered by the plunger 12, also hits directly on the moving contact 5, so that it is moved away from the fixed contact 4. Since the actuation of the moving contact 5 via the magnetic triggering system and the switching mechanism, ie on the chain of action plunger trigger lever switching mechanism reacts relatively sluggish, the direct action of the plunger 12 on the moving contact 5 takes place before the action via the switching mechanism.

FIG. 1B shows a detailed section (DD in 1A ) of the magnetic release mechanism 10. In the cylindrical bobbin 11, the plunger 12, which forms an anchor-plunger assembly together with the armature 13, slidably disposed in the longitudinal direction L. To amplify the magnetic effect of the coil, a magnetic core 15 is fixedly arranged in the bobbin 11. If the coil 11 is energized, the armature plunger assembly is linearly moved in the longitudinal direction L. In this case, the plunger 12 strikes a control contour 7 of the release lever 6. This is thereby also moved in the longitudinal direction L and strikes the moving contact 5, which thereby also in the longitudinal direction L - and thus away from the fixed contact 4 - is moved. To reset the armature plunger assembly to its initial position ie opposite to the longitudinal direction L, an armature spring 14 is provided, which is supported stationary and the armature 13 and thus the armature plunger assembly urges back to the starting position. Based on the presentation of the FIG. 1B it is clear that the plunger 12 first meets the trigger lever 6, which in turn actuates the moving contact 5. This results in a tolerance chain, which among other things is responsible for the sluggish reaction of this chain of action. A dynamic one Unlatching is not feasible in this arrangement, since the release lever 6 is not controlled by the moving contact 5.

The FIGS. 2A and 2B show schematically the triggering mechanism according to the invention ( 2B ) as well as the protective switching device 1 according to the invention ( 2A ). The protective switching device 1 in turn has two connection terminals 2, which can be electrically contacted by means of which it is to be monitored with an electrical line (not shown). The current from the terminal 2 shown on the left is guided via the coil 11 of the magnetic release mechanism 10 and the magnetic yoke 16 to the fixed contact 4. When the switch contact is closed, the current continues to flow via the moving contact 5 and a bimetal element 22, which is part of an overload release, to the terminal 2 shown on the right.

FIG. 2B provides a detailed section (CC in 2A It is clear that the control contour 7 of the release lever 6 is no longer arranged as in the prior art between fixed contact 4 and moving contact 5, but in the longitudinal direction L behind the moving contact 5. This arrangement allows a spatially closer arrangement of fixed contact 4 and moving contact 5, so that in the stromdurchlfossenen state, a higher Lorentz force between the two, substantially parallel sections of the moving contact and the fixed contact is achieved. Due to the substantially parallel current flow in the region of the switching contact, a Lorenz force is generated due to the guided in parallel, in the set direction by the short-circuit current conductor, which is directed such that the parallel adjacent conductors are pressed apart. In the case of a short circuit, ie from a predefined short-circuit current limit, the moving contact 5 is pushed away from the fixed contact 4 due to the Lorentz force acting between the line sections. This one as dynamic Contact opening designated effect is significantly improved by the narrow current flow in the region of the switch contact, ie by the inventive, directly adjacent arrangement of fixed contact 4 and moving contact 5 - without the release lever 6 arranged therebetween. In this way, an improved response of the protection device 1 can be realized.

For the technical realization of this arrangement, the moving contact 5 has an opening 8, through which the plunger 12 is guided with its end facing away from the armature 13 in the event of a short-circuit release. On a front side of this armature 13 facing away from the end of the plunger 12, a first active surface 17 is formed, which cooperates in the case of short-circuit release with the control contour 7 of the trigger lever 6 to effect a release of the switching mechanism of the protection device 1 by operating the trigger lever 6. Slightly offset from the first active surface 17, the plunger has a second active surface 18 in the form of a shoulder. About this second active surface 18 of the plunger 12 acts in the case of short-circuit release directly on the moving contact 5 a. In this case, the paragraph 18 proposes directly on the moving contact 5, in order to prevent welding of fixed contact 4 and moving contact 5 in the event of a short circuit. Both due to this transmitted by the plunger 12 of the magnetic release mechanism 10 on the moving contact 5 pulse, as well as acting due to the dynamic contact opening Lorentz force of the moving contact 5 is set in the longitudinal direction L in motion. He strikes the trigger lever 6 arranged behind it, whereby a unlatching of the switching mechanism of the protective device is also initiated. That is, in the case of the dynamic contact opening, a release of the switching mechanism is already initiated by the dynamic lifting of the moving contact 5 from the fixed contact 4, without requiring a corresponding movement of the inertial plunger 12 of the magnetic release mechanism 10 is required. The switching capacity is significantly improved.

LIST OF REFERENCE NUMBERS

1

Protection device

2

terminal

3

actuator

4

fixed contact

5

moving contact

6

sear

7

control contour

8th

opening

9

pawl

10

trigger mechanism

11

Kitchen sink

12

tappet

13

anchor

14

armature spring

15

core

16

yoke

17

first effective area

18

second effective area

21

hanger

22

bimetallic

D

axis of rotation

L

Longitudinal extension

Claims (6)

1. Tripping mechanism (10) for a protective switching device (1),

   - having a moving contact (5) which can be locked by means of a switching mechanism, having a plunger (12) and having a tripping lever (6),

   - in which the plunger (12) is provided both for operating the tripping lever (6), which is provided for unlocking the moving contact (5), and also for operating the moving contact (5) itself,

   - in which the plunger (12) has a first action area (17) which, in a first phase of the operating movement of the said plunger, acts on a drive contour (7) of the tripping lever (6) in order to unlatch the switching mechanism,

   - in which the plunger (12) has a second action area (18) which, in a second phase of the operating movement of the said plunger, acts directly on the moving contact (5), and

   - in which the moving contact (5) is arranged between the plunger (12) and the drive contour (7) of the tripping lever (6),

   characterized in that

   - the first action area (17) and the second action area (18) of the plunger (12) are formed at different points of the plunger (12), which points are offset in relation to one another, in the direction of the operating movement of the said plunger.
2. Tripping mechanism (10) according to Claim 1, in which the moving contact (5) has an opening (8) through which the plunger (12) partially extends in order to act on the drive contour (7) of the tripping lever (6).
3. Tripping mechanism (10) according to one of the preceding claims, in which the plunger (12) can be electromagnetically moved with the aid of a coil (11).
4. Tripping mechanism (10) according to one of the preceding claims, in which the tripping lever (6) is connected for releasing a latch (9) which is mechanically coupled to the moving contact (5).
5. Tripping mechanism (10) according to one of the preceding claims, in which the moving contact (5) forms a switching contact with a fixed contact (4) of the protective switching device (1), wherein the moving contact (5), in the event of dynamic contact opening of the switching contact, acts on the tripping lever (6) in such a way that the switching mechanism is unlatched as a result.
6. Electromechanical protective switching device (1) which has a tripping mechanism (10) according to one of Claims 1 to 5.

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