WO2012059418A1

WO2012059418A1 - Contact arrangement for a relay with two load current tracks and relay with contact arrangement

Info

Publication number: WO2012059418A1
Application number: PCT/EP2011/068952
Authority: WO
Inventors: Udo Gabel; Matthias Kroeker; Thomas Haehnel
Original assignee: Tyco Electronics Amp Gmbh
Priority date: 2010-11-03
Filing date: 2011-10-28
Publication date: 2012-05-10
Also published as: DE102010043352A1

Abstract

The invention relates to a contact arrangement (1) for a relay (28) and to a relay (28) with a contact arrangement (1) for switching a high load current. In order to minimise switching forces caused by the load current, it is provided according to the invention, that the contact arrangement (1) has at least two load current tracks (14, 15), which are electrically separated from one another, the relay (28) comprising one pair of counter-contacts (33, 33' and 34, 34') per load current track (14, 15).

Description

CONTACT ARRANGEMENT FOR A RELAY WITH TWO LOAD CURRENT

TRACKS AND RELAY WITH CONTACT ARRANGEMENT

The invention relates to a contact arrangement for a relay for switching a high load current, with an armature and a switching member connected to the armature in a movement-transmitting manner to conduct the load current. Furthermore, the invention relates to a relay for switching a high load current, with an actuator for producing switching forces acting on an armature and with counter-contacts to be bridged during a switching process.

Contact arrangements for a relay and relays for switching a high load current are widespread. To switch the load current, counter-contacts of load current connections of the relay are bridged by the contact arrangement. These relays are used, for example, to switch drive energy of an electrically operable car.

Because of the current displacement at the contact point of the contact pieces (high- current density), repulsive forces act on the contact pieces. Likewise, the Lorentz force acts on the movable current-carrying parts by means of the self-field of the current supplies. All these forces are proportional to the square of the impressed current. The linear connection between the force and the square of the current is in the order of magnitude of the magnetic field constant μθ, i.e. from a current flow of 1000 A, a separating force of several Newton's acts on the contact system. Owing to the quadratic dependency of the current, in the case of large excess currents, the repulsive force can cancel the closing force provided. The contact is pressed open by the current flow. The unloading of the contact by large currents leads to a rapid increase in the contact resistance and therefore to an inadmissible increase in the power conversion at the contact point. This is either the cause of an immediate welding of the switching pieces or leads to a complete destruction of the switching apparatus. At the moment of disengaging, the contact material abruptly evaporates under the action of an arc, the current flow collapses, the contacts close again and the process is repeated. It is therefore the object of the present invention to provide a contact arrangement for a relay, and a relay in which the forces caused by the high currents only occur in an attenuated form. The object is achieved according to the invention for the contact arrangement mentioned at the outset in that the switching member has at least two load current tracks, which are electrically separated from one another and preferably insulated, for the load current. For the relay according to the invention, the object is achieved in that the relay is configured with a contact arrangement according to the invention, the relay having one pair of counter-contacts per current path.

The current flow through individual current paths and the counter-contacts associated with them is reduced by the use of a plurality of current paths and the association of counter-contact pairs with a current path. If, for example, two load current tracks are used, half of the load current can in each case flow through one of the load current tracks. With the same high load current to be carried, the necessary force to keep the switching connection to a contact arrangement according to the invention and a relay according to the invention closed is halved. The solution according to the invention can be further improved by various configurations, which can be combined with one another as desired and are advantageous per se. These embodiments and the advantages connected with them will be dealt with below. The current paths may be arranged in a parallel connection in a closed switching state of the relay. This ensures that only a part of the high load current flows through one of the load current tracks in each case.

In order to be able to bridge counter-contacts of the relay, which are arranged spaced apart from one another, with the switching member, each of the load current tracks can have a contact bridge of the switching member. The contact bridge may, for example, be cylindrical and, in particular, beam-like, it being possible to arrange switching contacts provided on the contact bridge on one side of the contact bridge. The switching contacts may, for example, be arranged spaced as far as possible apart from one another on the contact bridge and pointing away from the armature and consist of a material which withstands the switching sparks or switching arcs well. Consequently, the switching contacts wear less as a result of many switching processes than, for example, switching contacts made of copper.

In order to prevent the switching process, in particular a process for closing the relay, from being impaired by so-called bouncing of the switching contacts of the switching member and the counter-contacts of the relays, the contact bridges can be resiliently mounted. In particular, the contact bridges can be elastically deflectable from their rest position relative to the armature.

The switching member may be formed with a bearing element, which is rigidly connected to the armature with respect to movement and on which the contact bridges are resiliently mounted. For example, the bearing element may be elongate and the contact bridges may be connected by spring elements to ends of the bearing element. The spring elements may, in this case, at at least two bearing portions that are spaced apart from one another of one of the respective contact bridges, connect the latter in a resilient manner to the bearing element. Each of the spring elements may be fastened both to one of the contact bridges and to the bearing element.

Owing to this arrangement of the spring elements, the switching elements of each contact bridge are elastically deflectable substantially independently of one another. If the geometry of one of the switching contacts should have changed more strongly by wear, for example by burn-off, than the geometry of the other switching contact of the contact bridge, the switching contacts of the contact bridge can nevertheless be brought into electrical contact with the counter-contacts. In order to not conduct the required separating force to open the switching connection via the spring elements, the switching member may have a driver rigidly connected to the armature with respect to movement to open the closed switching connection. On opening the relay, the driver can forcibly remove the contact bridges from the counter-contacts without the required switching forces being applied by the spring elements and the latter possibly becoming overloaded. The overloading of the spring elements can be prevented as even large separating forces are absorbed by the driver. These large separating forces can occur, for example, when the switching contacts are welded to the counter-contacts as a result of a switching process. A uniform opening of the relay is thereby also ensured, even if different forces are necessary to separate individual switching contacts from the respective counter-contacts. The contact arrangement is therefore optimally adapted both to the closing process and also to the process for separating the switching connection owing to the combination of the spring-elastic mounting of the contact bridges when closing the relay and the forced movement of the contact bridges produced by the driver when opening the switching connection.

In their rest position, the contact bridges can rest with their side remote from the armature on the driver and be resiliently pressed against the driver. Despite the movable mounting of the contact bridges by means of the spring elements, their position relative to the counter-contacts is well defined. Furthermore, the driver can have guide portions, by means of which a tilting of the contact bridges can be prevented. The guide portions may, for example, be configured by bent-over ends of the driver.

The contact bridges may be pressed against the driver in such a way that the spring elements are pre-stressed. With a large pre-stressing, the change of the contact force, with which the switching contacts are pressed against the counter-contacts, is even relatively small when the switching contacts or the counter-switching contacts are worn to different extents by burn-off In order to be able to arrange the switching contacts and the counter- contacts in the relay in such a way that the spacing of the respective contacts from one another is sufficient for air insulation, the contact bridges may be elongate and arranged spaced apart from one another transverse to their longitudinal axes. To transfer the switching member into a rest switching position, the contact arrangement may be configured with an armature spring which presses the armature into the rest switching position when the contact arrangement is assembled in the relay. For example, the rest switching position may be the opened switching position of the relay. A relay of this type is also called a closer relay as the actuator has to produce forces to close the relay in this case.

In order to be able to check whether the contact arrangement reaches its rest position when the actuator is inactive, the contact arrangement may comprise a locator. The locator can be immovably formed relative to the driver and, for example, be fastened to the armature. If the locator reaches the rest switching position, it can interact with a detector arranged in the relay. The detector can emit a signal during operation when the armature has reached its rest switching position or is arranged therein. It can thus be checked whether the armature spring has really transferred the switching member into the rest switching position or whether, for example, switching contacts and counter-contacts welded to one another are preventing an opening of the switching connection and consequently a return of the switching member into the rest switching position.

For example, the detector may be configured as a Hall sensor and the locator as a magnet interacting with the Hall sensor during operation. Alternatively, optical, capacitive or resistive locators and detectors can also be used. In order to minimise wear of the switching contacts and the counter-contacts during switching processes, wear caused by burn-off is to be avoided as far as possible, in particular. When switching high load currents and, in particular when separating the closed switching connection, switching arcs may occur, in which temperatures of several thousand kelvin can prevail. In particular, owing to the thermal energy produced in the arcs, the switching contacts and counter-switching contacts can melt and even evaporate. The material removal can lead to a deformation of the contacts and a failure of the relay. Consequently, it is desirable to keep the introduction of thermal energy into the contacts as small as possible. A shortening of the burning period of the arcs, which can be influenced by magnetic fields, can contribute to this, in particular. To produce the magnetic fields, the contacts, in each case, can be adjacent to at least one magnet and, in particular, flanked by two magnets. A pair of magnets may, for example, flank a switching pair composed of a switching contact and a counter-contact. The magnets may, for example, be configured as permanent magnets in the form of neodymium magnets.

As the high load current to be switched only flows proportionately through the respective contact bridges, these can be formed with a reduced cross-section in comparison to a contact bridge, which has to conduct the entire high load current. Owing to the smaller cross-section of the contact bridges, the magnets can therefore be arranged closer to the contacts, so the magnetic field is stronger in the region of the contacts and the possibly occurring arcs. The burning duration of the arcs can be reduced by this to 0.1 second or less.

The invention will be described by way of example below with the aid of embodiments with reference to the drawings. The different features of the embodiments may be combined here independently of one another, as has already been shown in the individual advantageous configurations.

In the drawings:

Fig. 1 shows a schematic view of a first embodiment of the contact arrangement according to the invention in a perspective view;

Fig. 2 shows a schematic sectional view of a first embodiment of the relay according to the invention;

Fig. 3 shows a schematic exploded view of a part of the relay according to the invention of Fig. 2; Fig. 4 shows a schematic perspective view of counter-contacts of the relay of the embodiment of Fig. 2.

The structure and function of a contact arrangement 1 according to the invention are firstly described with reference to the embodiment of Fig. 1. The contact arrangement 1 for a relay for switching a high load current is schematically shown here with an armature 2 and a switching member 3, the armature 2 and the switching member 3 being able to be rigidly connected to one another by means of an actuating rod 4. Furthermore, the contact arrangement 1 can also comprise an armature spring 5, which is configured as a helical spring in the embodiment shown. The actuating rod 4 can be guided by the helical armature spring 5 and projects together with the armature spring 5 from the armature 2 in the direction of the switching member 3.

The switching member 3 is shown by way of example with two contact bridges 6, 7. The contact bridges 6, 7 can, in each case, have two switching contacts 8, 8', 9, 9' and be arranged electrically insulated from one another in the switching member 3. The contact bridges 6, 7 are formed, by way of example, to be elongate and, for example, beam-like in the embodiment shown, the switching contacts 8, 8', 9, 9' being able to be arranged on sides 10, 11 pointing away from the armature 2 in the region of ends 12, 12', 13, 13 ' located in the longitudinal direction LI, L2. It is possible for there to be arranged between the switching contacts 8, 8' and 9, 9' of each of the contact bridges 6, 7, a load current track 14, 15, in each case, the course of which through the contact bridges 6, 7 is shown in Fig. 1 by a dash-dot line. The contact bridges 6, 7 can be arranged parallel to one another and held transversely to their longitudinal directions LI, L2 spaced apart from one another in the switching member 3. To at least minimise a so-called bouncing during closing of the relay, the contact bridges 6, 7 can be resiliently mounted in the switching member 3. Owing to the resilient mounting of the contact bridges 6, 7, these can be resiliently deflectable relative to the armature 2 parallel to a closing direction D, in particular toward the latter or away from it. The closing direction D points here from the armature 2 to the switching member 3. To position the contact bridges 6, 7 at spacing A transverse to the longitudinal directions LI, L2 thereof with respect to one another, the switching member 3 can have a bearing element 16, on which the contact bridges 6, 7 are resiliently mounted. The bearing element 16 can be rigidly connected to the armature 2 here with respect to movement and, for example, be fixed to the actuating rod 4 extending in the closing direction D. The bearing element 16 may be plate-like and extend substantially perpendicular to the actuating rod 4, the actuating rod 4 being able to project through a central region of the bearing element 16. Ends 17, 18 of the bearing element 16 pointing away from the actuating rod 4 can be oriented parallel to the actuating rod 4 and pointing away from the armature 2. The ends 17, 18 can be formed as guide portions here and prevent a displacement of the contact bridges 6, 7 away from one another, at least when the contact bridges 6, 7 are elastically deflected from their rest position R shown in Fig. 1 in the direction of the bearing element 16.

The contact bridges 6, 7 can be mounted by at least one spring element 19 on the bearing element 16. For example, the spring elements 19, 19' may have substantially S-shaped ends, which are arranged mirror-symmetrically with respect to one another and the bends of which pointing to one another can be connected to one another in one piece. The free bends pointing away from one another can be fastened to one of the contact bridges 6, 7.

The spring element 19 may comprise one or more springs, which, for example, can be leaf spring-like. A central region of a leaf spring element 20 of this type can be fixed to the bearing element 16, the ends of which arch away from the bearing element 16 and from the armature 2 and can be fixed to one of the contact bridges 6, 7. In particular, free ends 21 of the leaf spring element 20 can be fixed to bearing portions B, B', arranged spaced apart from one another, of each contact bridge 6, 7. The bearing portions B, B' can be configured on sides 22 of the contact bridges 6, 7 pointing away from the switching contacts 8, 8', 9, 9' and be configured for non-detachable connection to the spring elements 19, 19' . The ends 12, 12', 13, 13' can be resiliently mounted substantially independently of one another by means of an arrangement of this type of the spring element 19. The switching member 3 can be configured with a driver 23, by means of which the contact bridges 6, 7 can be moved away from counter-contact elements. The driver 23 can be configured similarly to the bearing element 16 and be arranged mirror-symmetrically with respect thereto, the contact bridges 6, 7 being able to be arranged between the driver 23 and the bearing element 16. In their rest position R, the contact bridges 6, 7 can rest with their sides 10, 11 pointing away from the armature 2 on the driver 23 and be pressed if possible by the pre-stressed spring elements 19, 19' against the driver 23. Owing to the pre-stressing of the spring elements 19, 19', it can be ensured that the switching contacts 8, 8', 9, 9', when the relay is in the closed switching state, always rest with a substantially identical force on counter-contacts, even if the shape of the switching contacts 8, 8', 9, 9' should have changed, for example, by burn-off

Sides 24, 25 of the contact bridges 6, 7 pointing away from the respective other contact bridge 6, 7 can rest on ends 26, 27 of the driver 23. The ends 26, 27 can be configured as guide portions for the contact bridges and be arranged running parallel to the actuating rod 4 and guide the contact bridges 6, 7 in a resilient deflection process in such a way that they cannot be tilted away from one another. The bearing element 16 and the driver 23 can be fixed at a constant spacing with respect to one another on the actuating rod 4.

Fig. 2 shows a first embodiment of a relay 28 according to the invention with the contact arrangement 1 of the embodiment of Fig. 1. For elements which correspond to the elements of the embodiment of Fig. 1 with the respective function and/or structure, the same reference numerals are used. For the sake of brevity, only the differences from the embodiment of Fig. 1 will be dealt with.

The relay 28 is shown in an open switching position, which corresponds to a rest switching position S of the contact arrangement 1 in the relay 28. In the rest switching position S, the armature 2 is pressed away from counter-switching contacts of the relay 28 by the armature spring 5. The relay 28 is thus formed as a closer, which does not conduct the load current in the unswitched state. Obviously, the relay 28 can also be configured as an opener or with a changeover contact.

The substantially cylindrical and, for example, circular-cylindrical armature 2 has, at its end pointing to the switching member 3, a collar 30 projecting away from a central opening 29. A cylindrical portion 31 extending from the collar and pointing away from the switching member 3 is configured with a smaller diameter than the collar 30 and arranged in a guide sleeve 32 of the relay 28. The armature spring 5 presses the armature of this relay 28 configured as an opener away from the counter-contacts of the relay 28, only two counter-contacts 33, 34 being shown here. However, the relay can have one counter-contact 33, 34 for each switching contact 8, 8', 9, 9' . The counter-contacts 33, 34 may be electrically conductively connected to one another and to a load current connection 35 of the relay 28. The load current can be supplied to the relay 28 or removed therefrom via the load current connection 35, when the contact arrangement 1 is arranged offset in the closing direction D from the rest switching position S shown. For example, a control signal can be supplied to the relay 28 via a control connection 36. With the aid of the control signal, the actuator 37 arranged in the relay 28 and configured, for example, as a coil, can produce a magnetic field exerting a force on the armature 2, said magnetic field displacing the armature 2 and therefore also the switching member 3 in the closing direction D toward the counter-contacts 33, 34.

The central opening 29 of the armature 2 may be cup-like, in particular, so that at least the armature spring 5 or else the actuating rod 4 can be arranged, at least in portions, in the opening 29. Both the actuating rod 4 and the armature spring 5 may be fixed on the base of the opening 29 on the armature 2. In the embodiment shown, the base of the opening 19 is open and, for example, configured as a hole, to which the actuating rod 4 can be screwed or otherwise rigidly connected.

A locator 38, which interacts with a detector 39 in the rest switching position S, can be arranged on an end of the armature 2 pointing away from the switching member 3. For example, the locator 38 and the detector 39 can be arranged closer together in the rest switching position S than in other switching positions. In particular, the locator 38 can be formed as a permanent magnet and the detector 39 as a Hall sensor. The locator 38 can be fastened by a fastening element 40 to the armature 2 or, for example, to the actuating rod 4. By means of this fastening, the locator 38 can be rigidly provided with respect to movement, in particular with respect to the driver 23 in the relay 28. As the driver 23 forcibly guides the contact bridges 6, 7 during the change of a closed switching state into the open switching or rest state S shown, it is ensured that the switching position of the relay is always open when the locator 38 is arranged close to the detector 39.

The contacts 8' and 33 and 9' and 34 oppose one another pair-wise. Both the contact pair 8', 33 and the pair 9', 34 are arranged between two permanent magnets 42. The magnetic field of the permanent magnets 42 disturbs the formation and/or maintenance of switching arcs, which can occur when the closed connection of the switching contact 8', 9' and counter-contact 33, 34 is opened. As a result, switching arcs burn more briefly than without permanent magnets 41, so less thermal energy is introduced into the contacts 8', 9', 33, 34 involved and these wear less as a result of burn-off.

Both the load current connection 35 and the permanent magnets 41 are shown floating freely within a switching chamber 42 of the relay 28 in Fig. 2. To fix at least the load current connection 35 and the permanent magnets 41, the relay can at least have one fixing member, which is shown in the following figures.

The switching chamber 42 can be separated by an assembly plate 43 from a control chamber 44, in which the actuator 37 and the armature 2 are arranged. The actuating rod 4 can project from the control chamber 44 into the switching chamber 42 through the assembly plate 43.

The relay 28 can be configured with a housing 45, which encloses the switching chamber 42 and the control chamber 44 and can form a continuous receiving volume for the remaining components of the relay 28 without the assembly plate 43. At least the switching chamber 42 can be accessible from the outside through an assembly opening 46 provided in the housing 45. In the embodiment shown, the assembly opening 46 is closed by a lid 47. The housing 45 itself and components of the relay 28 arranged in the housing 45 can be connected to one another in such a way that moisture cannot penetrate into the housing 45 or from a part region of the housing 45 into another part region. Thus, the use of the relay 28 can be ensured even in moist environments, for example in the engine compartment of a car.

Fig. 3 shows parts of the relay 28 of the embodiment of Fig. 2 without the housing 45 in an exploded view.

In Fig. 3, the actuator 37 is shown assembled in a holding bracket 48, the holding bracket 48 being open toward the assembly plate 43 and being fastened by this open end to the assembly plate 43. The assembly plate 43 closes the open end 48 of the holding bracket.

The switching member 3 is arranged on the side of the assembly plate 43 remote from the actuator 37. Each of the switching contacts 8, 8', 9, 9' is flanked, transverse to the closing direction D, by two permanent magnets 41, which extend substantially in the closing direction D and along contact bridges 6, 7. Two magnets 41 are shown arranged on the inside faces of two sides of a holding clamp 49, which is substantially U-shaped. The holding clamp 49 may, for example, be formed from a magnetically conductive material. In addition to the load current connection 35, a second load current connection 50 is shown here, which can be configured similarly to the load current connection 35. The load connections 35, 50 are arranged behind the switching member 3 in the closing direction D. When the relay 28 is assembled, the counter-contacts 33, 34 of the load current connection 35 and the counter-contacts of the load current connection 50 project into the intermediate spaces of two magnets 41, which are fixed on a holding clamp 49. The contacts of the pairs of switching contacts 8, 8', 9, 9' and counter-contacts 33, 34 can be arranged opposing one another in the closing direction D.

To fix the magnets 41 and the load current connections 35, 50, the relay 28 can have a fixing member 51, with which the magnets 41 and the load current connections 35, 50 can, for example, be positively connected to one another. The fixing member 51 can be secured by a holding connector 52 in the relay 28 against slipping, at least transverse to the closing direction D, the holding connector 52 being able to be fixed in a peripheral groove of the assembly plate 43.

Fig. 4 shows the fixing member 51 with magnets 41 and load current connections 35, 50.

Connecting regions 53, 54 of the load current connections 35, 50 project from the fixing member 51. The fixing member 51 is shown in the closing direction D, so the counter- contacts 33, 34 of the load current connection 35 and the counter-contacts 33', 34' of the load current connection 50 project out of the plane of the drawing.

When the relay 28 is in the electrically conductive state, the counter-contacts 33, 33 ' are electrically bridged by the contact bridge 6 and the counter-contacts 34, 34' by means of the contact bridge 7. The contact bridges 6, 7 are indicated here by dashed lines. The current path 55 resulting for the load current is inter alia composed of the load current tracks 14, 15 shown by dash-dot lines and arranged in a parallel connection P here. Half the load current flowing via the load current connections 35, 50 in the embodiment shown, in each case, flows through one of the load current tracks 14, 15.

The fixing member 52 can preferably be configured, at least in portions, complementary to the contact bridges 6, 7 and the driver 23. In particular, the fixing member 52 can have a substantially H-shaped receiving region 56, in which the contact bridges 6, 7 and the driver 23 can be at least partially arranged, when the relay 28 is closed. In this case, a transverse connection of the H-shaped receiving region 56 can be configured as a receiving trough 57 for the receiver 23. The receiving trough 57 can be configured so deep in the closing direction D that the contact bridges 6, 7 no longer rest on the driver 23 when the relay 28 is closed, but are arranged elastically deflected and spaced apart from the driver 23. This may even be the case if at least one of the switching contacts 8, 8', 9, 9' or the counter-contacts 33, 33', 34, 34' is worn by burn-off.

Claims

1. Contact arrangement (1) for a relay (28) for switching a high load current, with an armature (2) and a switching member (3) connected in a movement transmitting manner to the armature (2) to conduct the load current, characterised in that the switching member (3) has at least two load current tracks (14, 15), which are electrically separated from one another, for the load current.

2. Contact arrangement (1) according to claim 1, characterised in that each of the load current tracks (14, 15) has a contact bridge (6, 7) of the switching member (3).

3. Contact arrangement (1) according to claim 2, characterised in that the contact bridges (6, 7) are resiliently mounted.

4. Contact arrangement (1) according to claim 2 or 3, characterised in that the contact bridges (6, 7) can be elastically deflected relative to the armature (2) from their rest position (R).

5. Contact arrangement (1) according to any one of claims 2 to 4, characterised in that the switching member (3) has a driver (23), which is rigidly connected to the armature (2) with respect to movement, to open a closed switching connection of the contact bridges (6, 7) to counter-contacts (33, 33 ', 34, 34') of the relay (28).

6. Contact arrangement (1) according to claim 5, characterised in that in the rest position (R), the contact bridges (6, 7) rest with their side (10, 11) remote from the armature (2) on the driver (23) and are resiliently pressed against the driver (23).

7. Contact arrangement (1) according to any one of claims 2 to 6, characterised in that the contact bridges (6, 7) are elongate and are arranged spaced apart from one another transverse to their longitudinal axes (LI, L2).

8. Contact arrangement (1) according to any one of claims 2 to 7, characterised in that each of the contact bridges (6, 7) has at least two bearing portions (B, B'), by means of which the contact bridge (6, 7) is resiliently mounted.

9. Contact arrangement (1) according to any one of claims 5 to 7, characterised by a locator (38) immovably formed relative to the driver (23).

10. Relay (28) for switching a high load current, with an actuator (37) for producing switching forces acting on an armature (2) and with counter-contacts (33, 33', 34, 34') to be bridged during a switching process, characterised by a contact arrangement (1) according to any one of claims 1 to 8, the relay (28) having one pair of counter-contacts (33, 33', 34, 34') per load current track (14, 15).

11. Relay (28) according to claim 10, characterised in that when the relay (28) is in a closed switching state, the load current tracks (14, 15) are arranged in a parallel connection (P).

12. Relay (28) according to claim 10 or 11, characterised in that the contact bridges (6, 7), upon a movement of the driver (23) in an opening direction pointing counter to the closing direction (D) and away from the counter-contacts (33, 33', 34, 34'), are forcibly moved by the driver (23).

13. Relay (28) according to any one of claims 10 to 12, characterised in that the relay (28) is provided with a detector (39), which emits a signal during operation when the armature (2) is arranged in its rest switching position (S).