DE102019117804B4 - Switching device with an electrical contact system - Google Patents

Abstract

Switching device (1) with an electrical contact system (2), comprising at least one contact pair (3) consisting of a fixed contact piece (4) which is attached to a first busbar (6) which is fixed to a housing of the switching device (1), and a contact piece (5) which can be moved relative to the fixed contact piece (4) for a switching function, the contact pieces (4, 5) of the at least one contact pair (3) being positioned relative to one another in such a way that the movable contact piece (5) by means of a contact force (26 ) can be pressed onto the fixed contact piece (4), - a flat contact piece carrier (7) for the at least one movable contact piece (5), which in its longitudinal section along its longitudinal axis from a first end (11) to a second end (12) in It is essentially straight and is attached at the first end (11) to a second busbar (13) which is fixed to the one housing of the switching device (1) and, together with this, a V-shape in longitudinal section b The at least one movable contact piece (5) is arranged and fastened in a region of the second end (12) of the contact piece carrier (7), - a spring element (18) with no or lower electrical conductivity and / or with an electrically insulating coating , wherein the spring element (18) is attached to the second busbar (13) and has at least one spring arm (20) with a first spring arm section (22) and a second spring arm section (23), and wherein the first spring arm section (22) has a fastening section (19) extends up to a position with at least one pressure point (24) and the second spring arm section (23) extends from this position to a free end (21) of the spring arm (20), and wherein the at least one pressure point (24) is positioned such that a direct or indirect non-positive connection (25) between the pressure point (24) and the movable Ko ntaktstück (5) can be generated and thus a contact force (26) can be generated.

Description

The invention relates to a switching device with an electrical contact system, the switching devices for which the invention is applicable include relays, switches, contactors and circuit breakers.

• ➢ einen geringen elektrischen Widerstand zwischen den Anschlussklemmen, wodurch eine hohe Wirtschaftlichkeit aufgrund einer geringen Verlustleistung sowie Sicherheit des Gerätes im Betrieb, insbesondere hinsichtlich Erwärmung und Brandschutz, erreicht wird,
• ➢ eine möglichst große Lebensdauer, das heißt, eine möglichst große Anzahl an Schaltungen unter Last,
• ➢ Sicherheit gegen ein Kontaktkleben in Folge großen Kurzschlussstromes, beispielsweise im elektrischen Fehlerfall.

Switching devices such as relays, switches, contactors and circuit breakers should have the following properties:

• ➢ a low electrical resistance between the connection terminals, which results in a high level of economy due to a low power loss and safety of the device in operation, in particular with regard to heating and fire protection,
• ➢ the longest possible service life, i.e. the largest possible number of switching operations under load,
• ➢ Security against contact sticking as a result of large short-circuit currents, for example in the event of an electrical fault.

In conventional switching devices, spring elements ensure a quick lifting of the movable contact piece from the fixed contact piece during the release of the contact, which reduces the wear of the contact pieces.

In relays in particular, such spring elements are typically elements made of steel that are riveted to the movable contact piece. The disadvantages of these steel elements riveted to the movable contact consist in a high load and a low mobility, which in turn only allows a low tolerance compensation.

Also known are spring elements made of steel which are attached to a magnetic actuator of the switching device or a mechanical coupling element, referred to below as a slide. The magnetic actuator generates and the slide transmits the force to open or close the contacts. A spring can be used to release two or more contacts at the same time. However, the fastening of the spring elements on the actuator or on the slide has the disadvantage that a device constructed in this way is hardly suitable for a time-delayed opening or closing of at least two pairs of contacts. Such a time-delayed opening or closing of the contacts is also referred to as lead-lag switching behavior.

Another variant known from the prior art consists in integrating the spring element into a current path of the contact piece carrier for the movable contact piece. However, this would lead to an even higher mechanical load than the above-mentioned direct attachment of the spring element to the movable contact piece. In addition, there is the disadvantage that the spring heats up, which can lead to a deformation of the slide and thus to a shortening of the service life of the contact system. In addition, rolling movements of the contacts are restricted by the contact piece carrier deformed during the short circuit due to the conditions mentioned below. In the event that the spring element is fastened, for example riveted, to the movable contact piece, a high degree of rigidity leads to a lower flexibility of the spring element and thus to a restriction of the rolling movements of the contacts. If the spring is integrated into the contact piece carrier of the movable contact piece, the restriction of the rolling movements arises from a reduced flexibility of the current path of the contact piece carrier of the movable contact piece.

From the US 7 659 800 B2 an electromechanical relay is known which comprises a housing and a magnet system having a coil, a coil core and an armature. Furthermore, the relay comprises two toggle switches, each with two fixed contacts and a contact spring, each contact spring having a stationary end and a segment which carries a contact element that is movable between the two fixed contacts. In addition, the relay includes an actuator that couples the movable segments of the contact springs with the armature and the coil. The fixed contacts of the toggle switches, the stationary ends of the contact springs and the coil are each connected to different connecting elements.

The object of the invention on which the invention is based is to provide a switching device with a space-saving, inexpensive to manufacture electrical contact system, which is powerful, has a long service life and allows safe absorption and transmission of the short-circuit forces.

The object of the invention is achieved by a switching device with an electrical contact system having the features of claim 1. Further developments are given in the dependent claims.

• - mindestens ein Kontaktpaar, das aus einem Festkontaktstück, welches an einer ersten zu einem Gehäuse der Schalteinrichtung ortsfesten Stromschiene befestigt ist, und einem zu dem Festkontaktstück für eine Schaltfunktion relativ bewegbaren Kontaktstück besteht, wobei die Kontaktstücke des mindestens einen Kontaktpaares derart zueinander positioniert sind, dass das bewegbare Kontaktstück mittels einer Kontaktkraft auf das Festkontaktstück pressbar ist,
• - einen flächigen Kontaktstückträger für das mindestens eine bewegbare Kontaktstück, der in seinem Längsschnitt entlang seiner Längsachse von einem ersten Ende bis zu einem zweiten Ende im Wesentlichen gerade ausgebildet und am ersten Ende an einer zweiten zu dem einen Gehäuse der Schalteinrichtung ortsfesten Stromschiene befestigt ist und zusammen mit dieser im Längsschnitt eine V-Form bildet, wobei in einem Bereich des zweiten, freien Endes des Kontaktstückträgers das mindestens eine bewegbare Kontaktstück angeordnet und befestigt ist,
• - ein Federelement ohne oder mit niedriger elektrischer Leitfähigkeit und/oder mit einer elektrisch isolierenden Beschichtung, zum Beispiel einem Isolationslack, wobei das Federelement an der zweiten Stromschiene befestigt ist und mindestens einen Federarm mit einem ersten Federarmabschnitt und einem zweiten Federarmabschnitt aufweist, und wobei der erste Federarmabschnitt von einem Befestigungsabschnitt bis zu einer Position mit mindestens einer Druckstelle verläuft und der zweite Federarmabschnitt sich von dieser Position bis zu einem freien Ende des Federarms erstreckt.

A switching device designed according to the invention, such as a relay, comprises an electrical contact system, which in turn comprises the following:

• - At least one contact pair, which consists of a fixed contact piece, which is attached to a first busbar, which is fixed to a housing of the switching device, and one to the fixed contact piece for a switching function consists of a relatively movable contact piece, the contact pieces of the at least one contact pair being positioned relative to one another in such a way that the movable contact piece can be pressed onto the fixed contact piece by means of a contact force,
• - A flat contact piece carrier for the at least one movable contact piece, which is essentially straight in its longitudinal section along its longitudinal axis from a first end to a second end and is fastened at the first end to a second busbar fixed to the one housing of the switching device and together forms a V-shape with this in longitudinal section, the at least one movable contact piece being arranged and fastened in a region of the second, free end of the contact piece carrier,
• - A spring element with no or low electrical conductivity and / or with an electrically insulating coating, for example an insulating varnish, wherein the spring element is attached to the second busbar and has at least one spring arm with a first spring arm section and a second spring arm section, and the first The spring arm section extends from a fastening section to a position with at least one pressure point and the second spring arm section extends from this position to a free end of the spring arm.

According to the invention, the at least one pressure point is positioned such that a direct or indirect non-positive connection between the pressure point and the movable contact piece can be generated by pretensioning the spring element and thus a force can be generated on the contact pair.

The concept according to the invention consists in the use of a spring element with low conductivity and with sole attachment to the same busbar on which the contact piece carrier for the movable contact piece is also attached. Such a spring element connects various advantageous mechanisms of action with one another.

The spring element can consist of a paramagnetic or alternatively of a diamagnetic material. The spring element preferably consists of a material with paramagnetic properties. Particularly preferred materials are stainless steel or stainless steel alloys. In any case, the material of the spring element must be less conductive in relation to the material of the stationary busbar and the contact piece carrier, so that as little current as possible flows through the spring element. The difference in conductivity between steel and copper is a factor in the range between 6 - 7.If the stationary busbar and the contact carrier are made of aluminum instead of copper, for example, and the spring is still made of steel, the factor between the conductivities is around 4, which is is also still sufficient. A sufficiently low conductivity for the spring element is given for all materials that are not more conductive than steel.

An advantageous effect is based on the generation of a force on the contact pairs which is brought about by a pretensioning of the spring element and which fits the contact pieces together. This creates the contact points, so-called A spots, at the interface between the contact pieces, these contact points enabling the flow of current. The higher the contact force, the larger the area of the contact point that is available for the flow of current, and the lower the electrical resistance in the contact point.

According to a preferred embodiment of the invention, in which the contact system comprises a plurality of contact pairs, a further improvement over the prior art is achieved by generating the contact force separately for each of the separable contact pairs. Several pairs of contacts can be connected in parallel in order to keep the electrical resistance consistently low over the service life even if one pair of contacts is consumed. A plurality of movable contact pieces can be arranged on the contact piece carrier transversely to its longitudinal axis or one behind the other in the direction of the longitudinal axis or transversely to the longitudinal axis, but offset in the direction of the longitudinal axis. As already mentioned above, a contact pair that experiences the burn changes its geometric shape, for example through the burn itself or, especially in the case of bi-metal contact rivets, through delamination. The change in shape causes a change in the important spring preload and thus also in the contact force. So that contact pairs without erosion experience no change due to such contact pairs with erosion, the force is generated separately for each contact pair. This is implemented by the advantageous design of the spring element as a leaf spring with separate spring arms for each contact pair. This results in a low electrical resistance even when using several pairs of contacts, one of which burns off.

Another aspect of the invention relates, for example, as a switching device to a relay which comprises the electrical contact system. A corresponding switching device further comprises an excitation coil, a lifting magnet referred to as an armature and one with the armature in one Operationally connected mechanical coupling element, such as a slide. A force can be generated by the excitation coil due to the magnetic field generated by it, which force can be transmitted to the contact system by means of the armature and the mechanical coupling element, so that the contact system can be switched by the excitation coil.

Another advantageous mechanism of action of the spring element is based on the generation of a force on the armature / lifting magnet, which supports it during the opening process, so that the contact or contacts can be opened at the highest possible speed. The greater the pretensioning force by the spring element, the higher the opening speed of the contacts and the lower the contact erosion as a result of the opening arc when the electrical load is disconnected. The lower the contact erosion, the more switching operations can be performed, which increases the service life of the corresponding switching device.

The low spring constant of the spring element is particularly advantageous. The spring constant generally indicates the ratio of the force acting on the spring to the deflection of the spring caused thereby. After the contacts have opened, a large part of the spring force on the lifting magnet is lost due to the system. Only a fraction of the contact force acts, which results from the pretensioning of the spring element (leaf spring) between the movable contact piece and the busbar connected to the movable contact piece carrier. This force component counteracts the opening movement and increases with increasing contact opening, since the spring section is increasingly pretensioned with the opening movement. The low spring constant means that the increasing preload path only leads to a minimal increase in force, so that the lifting magnet is only slightly braked in the opening movement. This results in a faster opening movement of the contacts and thus a longer service life of the device.

Another advantage is based on the high heat resistance of the spring material. The contact system heats up during the switching process. The spring material has a corresponding heat resistance, which ensures the mechanical properties at elevated temperatures.

Another advantageous effect is based on the fact that the spring material has little or no electrical conductivity and, for example, in the case of using stainless steel, a paramagnetic behavior. The relationship between low conductivity or paramagnetic properties of the spring element and the advantageous effect, namely the prevention of contact welding, is explained in more detail below.

In order to prevent contact welding in the event of a short circuit, two effects are decisive. One of these effects is a relative movement between the switching contact pieces while the current flows through the contact pieces. Another effect is the application of an increased contact force to enlarge the contact area, which on the one hand reduces the current density at the point of contact between the contact pieces and on the other hand compensates for the narrow Holm force caused by the current flow between the contacts. Holm's narrow force always acts in the contact opening direction and, without a corresponding counterforce, would lead to the contacts opening in the event of a short-circuit fault. The forces required to implement these effects are generated by magnetic fields. The magnetic fields in turn result from the short-circuit current itself. These effects should not be influenced by the spring element. On the one hand, the low electrical conductivity prevents a large short-circuit current from flowing through the spring element, so that no relevant magnetic field is formed around the spring element. On the other hand, the development of reluctance forces on the spring or surrounding components as a result of the magnetic fields around the current path can be prevented by paramagnetic properties of the spring element. Thus, a contribution is made to the security against contact gluing in that the actual operating principle, namely the relative movement between the switching contact pieces, is not influenced by the spring element.

Another advantageous mechanism of action is achieved by generating an orthogonal force effect on the contact point by means of the spring element. There is a non-positive connection between the switching electrical contact and the spring element as a result of the spring preload. The force effect does not contain any torque component. The spring element rests with its pressure point or its pressure points on the rear side of the movable contact piece or on the areas of the contact piece carrier adjoining the movable contact piece and is not attached to it. Thus, a compressive force, also referred to below as normal force, can only be transmitted orthogonally from the spring element to the contact. The transmission of a torque or significant transverse force is not possible or is prevented as a result. As a result, in the event of a short circuit, the described relative movement transverse to the contact surface is not hindered. This results in increased security against contact gluing, since the applied operating principles are not influenced.

In a particularly preferred embodiment of the invention, the at least one movable contact piece extends with a projection formed on its rear side, also referred to as a rivet neck, through a corresponding receiving hole in the contact piece carrier. This makes it possible for the spring arm of the spring element to lie directly on the projection of the contact piece, the rivet neck, with a pressure point and press. Preferably, however, the at least one spring arm in the area of the pressure points has an annular section widened transversely to the longitudinal axis of the contact piece carrier with a central recess, which is placed in such a way that it rests on the contact piece carrier in the pretensioned state and the projection formed on the rear side of the movable contact piece enclosing it in a ring. In this embodiment, the at least one spring arm preferably has two pressure points at opposite positions of the widened annular section.

It is also possible to use contact pieces without a rivet neck. These can be soldered or welded onto the contact piece carrier so that no receiving hole is necessary. In this case, the spring arm of the spring element could rest or press with only one pressure point directly on the contact piece carrier on the rear side of the fastening point of the movable contact piece.

Further details, features and advantages of embodiments of the invention emerge from the following description of exemplary embodiments with reference to the associated drawings.

• 1: eine Schnittdarstellung eines elektrischen Kontaktsystems mit einem Federelement in einem Relais als Schalteinrichtung,
• 2: eine Seitenansicht eines Teils des elektrischen Kontaktsystems,
• 3: ein Federelement mit zwei Federarmen,
• 4: eine perspektivische Ansicht eines elektrischen Kontaktsystems mit zwei Kontakten und
• 5: eine Vorderansicht eines Teils eines elektrischen Kontaktsystems mit zwei Kontakten unterschiedlicher Größe.

Show it:

• 1 : a sectional view of an electrical contact system with a spring element in a relay as a switching device,
• 2 : a side view of part of the electrical contact system,
• 3 : a spring element with two spring arms,
• 4th : a perspective view of an electrical contact system with two contacts and
• 5 : a front view of part of an electrical contact system with two contacts of different sizes.

the 1 shows a schematic sectional view of a relay 1 as an example of a switching device 1 , in which an electrical contact system 2 with the features of the present invention is used. The electrical contact system 2 includes at least one contact 3 by a pair of contact pieces 4th , 5 is formed. The at least one contact consists of a fixed contact piece 4th on a first busbar fixed to a housing of the switching device 6th is attached, and one to the fixed contact piece 4th for the switching function relatively movable contact piece 5 , wherein the contact pieces of the at least one contact are positioned relative to one another in such a way that the movable contact piece 5 by means of a contact force on the fixed contact piece 4th is compressible.

It also includes the electrical contact system 2 a flat contact piece carrier 7th for at least one movable contact piece 5 . This contact piece carrier 7th can have spring properties and is therefore often referred to as a contact spring.

The flat contact piece carrier 7th is as shown in 1 from two superimposed current paths 8th , 9 constructed and in its longitudinal section along its longitudinal axis from a first end 11 until a second end 12th essentially straight. With the first ending 11 is the contact piece carrier 7th on a second busbar fixed to the one housing of the switching device 13th attached, preferably riveted, and together with this forms a V-shape in longitudinal section. In the area of the second, free end of the contact piece carrier 7th is the at least one movable contact piece 5 attached. In the embodiment shown, there is the contact piece carrier 7th from a first, straight current path 8th and a second current path 9 , the second current path 9 with the exception of an arched section protruding outward from its plane 10 , which extends transversely to the longitudinal axis over the entire width of the contact piece carrier, is also straight. The arch section 10 is also called a bead 10 designated. The bead 10 is near the first end 11 of the contact piece carrier 7th with which the contact piece carrier 7th on the second busbar 13th is attached.

The relay 1 also has a magnetic drive to deflect the contact piece carrier 7th in the respective relay position. The magnetic drive has a magnetic coil, a permanent magnet and an armature 14th on, which is held pivotably on the solenoid between two switching positions. The anchor 14th is with a mechanical coupling element 15th in the form of a slide 15th connected in such a way that by the pivoting movement of the armature 14th the slide 15th can be raised and lowered. Hence the anchor 14th can also be referred to as a lifting magnet. The anchor 14th is in the direction of movement of the slide's lifting and lowering movement 15th through the slider 15th at its lower end area 16 both undermined and undermined. The top end 17th of the slide 15th lies in the area of the free end 12th of the contact piece carrier 7th at the bottom. Thus, by means of the slide 15th that with an anchor 14th connected, one due to the action of an excitation coil in a relay 1 generated magnetic field caused force on the contact piece carrier 7th with the at least one movable contact piece attached thereto 5 be transmitted so that the contact between the fixed contact piece 4th and the movable contact piece 5 can be opened or switched by the excitation coil.

The contact system 2 comprises a spring element as an essential feature of the invention 18th with low conductivity, which is preferably made of stainless steel or a stainless steel alloy. This spring element 18th is on the second busbar 13th attached to which the contact piece carrier 7th for the movable contact piece 4th is appropriate. The spring element 18th includes an attachment portion 19th with which the spring element 18th on the second busbar 13th attached, preferably riveted. The spring element 18th has, starting from the fastening portion 19th at least one spring arm 20th on that of the mounting portion 19th to a free end 21 of the spring element 18th runs. The at least one spring arm 20th can be divided into two different spring arm sections 22nd , 23 subdivide. A first spring arm section 22nd runs from the fastening section 19th up to a pressure point 24 with which the spring element 18th on the back of the movable contact piece 5 or on the back of the movable contact piece 5 adjacent area of the contact piece carrier 7th only rests, but not on the contact piece 5 or on the contact piece carrier 7th is attached. Starting from the pressure point 24 extends the second spring arm section 23 to the free end 21 of the spring arm 20th . This increases, starting from the pressure point 24 , on which the spring element is still on the movable contact piece 5 or the contact piece carrier 7th rests, in the course to the end 21 of the spring arm 20th , the distance between the contact piece carrier 7th and the second spring arm section 23 . That means that the two different spring arm sections 22nd , 23 together form a V shape.

A spring element designed in this way 18th combines various beneficial mechanisms of action with one another. Thus, a bias of the spring element 18th , shown schematically by the representation of the second spring arm section 23 as a continuous line, a non-positive connection 25th between the pressure point 24 and the movable contact piece 5 and consequently a force on the contact 3 that generates the contact pieces 4th , 5 squeezes and through the arrow 26th is shown. By the force 26th on the contact 3 the contact points, so-called A-spots, arise at the interface between the contact pieces 4th , 5 , these contact points allowing the flow of current. The higher the contact force, the larger the area of the contact point for the current flow, indicated by the arrows 27 , is available and the lower the electrical resistance in the contact point.

Another advantageous mechanism of action of the spring element 18th is based on the generation of a force on the anchor 14th or lifting magnets 14th , where this force that is in 1 by the arrow 28 is represented, the anchor 14th supported during the opening process. This force also ensures that the contact or contacts 3 can be opened as fast as possible. The greater the preload force from the spring element 18th the higher the opening speed of the contacts 3 .

After opening the contacts 3 Due to the system, a large part of the spring force on the armature is eliminated 14th or lifting magnets 14th . Although the spring arm section is 23 biased at all times, but when the electrical contacts open, there is mechanical contact between the second end 12th the contact piece carrier and the slide 15th produced. This shifts the flow of force. The preload force of the spring element 18th is completely in the slide 15th intercepted and no longer over the anchor 14th derived. The resulting force from the spring preload 28 on the anchor 14th becomes zero when the contacts are opened. This state is in 1 schematically in the form of the second spring arm section drawn as a dashed line 23 ' shown. Only a fraction of the previously applied contact force acts, which is the result of the pretensioning of the first spring arm section, which acts like a leaf spring 22nd between the movable contact piece 5 and the one with the movable contact piece carrier 7th connected busbar 13th results. This force component acts on the opening movement of the movable contact piece 5 counteracts and increases with increasing contact opening, since the spring arm section 22nd is increasingly biased with the opening movement. The low spring constant means that the increasing preload path only leads to a minimal increase in force, so that the lifting magnet 14th is only slightly braked in the opening movement. This results in a faster opening movement of the contacts 3 and thus a longer service life of the device.

In addition, there is an advantageous effect through the generation of an orthogonal force effect on the contact point by means of the spring element 18th achieved. Between the switching electrical contact 3 and the spring element 18th there is a force-fit connection as a result of the spring preload. The force effect does not contain any torque component. The spring element 18th lies with its pressure point 24 on the back of the movable contact piece 5 or on the back of the movable contact piece 5 adjacent area of the contact piece carrier 7th only on and is not attached to it. Thus, a compressive force can only be applied orthogonally from the spring element 18th on the contact 3 be transmitted. The transmission of a torque or significant transverse force is not possible or is prevented as a result. As a result, in the event of a short circuit, a relative movement transverse to the contact surface or the rolling movement is not hindered. This results in increased security against contact gluing.

the 2 shows a side view of part of the electrical contact system 2 . This part of the electrical contact system 2 includes the flat contact piece carrier 7th for at least one movable contact piece 5 . It is as shown in 2 from two superimposed current paths 8th , 9 constructed and in its longitudinal section along its longitudinal axis from a first end 11 until a second end 12th essentially straight. With the first ending 11 is the contact piece carrier 7th on the second busbar 13th attached by means of a rivet connection and forms together with the busbar 13th V-shape in longitudinal section. In the area of the second, free end 12th of the contact piece carrier 7th is the at least one movable contact piece 5 attached. The contact piece carrier 7th consists of a first, straight current path 8th and a second current path 9 , the second current path 9 with the exception of an arched section protruding outward from its plane 10 who is in to the first end 11 adjacent area extends transversely to the longitudinal axis over the entire width of the contact piece carrier, is also straight. On the second busbar 13th is apart from the contact piece carrier 7th the spring element 18th attached. The spring element 18th includes an attachment portion 19th with which the spring element 18th on the second busbar 13th is preferably attached by means of a rivet connection. The spring element 18th has, starting from the fastening portion 19th the spring arm 20th on that of the mounting portion 19th to the free end 21 of the spring element 18th runs. The spring arm 20th can be divided into two different spring arm sections 22nd , 23 subdivide. A first spring arm section 22nd runs from the fastening section 19th up to the pressure point 24 with which the spring element 18th on the back of the movable contact piece 5 or on the back of the movable contact piece 5 adjacent area of the contact piece carrier 7th only rests, but not on the contact piece 5 or on the contact piece carrier 7th is attached. Starting from the pressure point 24 extends the second spring arm section 23 to the free end 21 of the spring arm 20th . The two spring arm sections 22nd , 23 together form a V-shape.

the 3 shows a spring element 18th , which is designed according to an advantageous embodiment of the invention. This embodiment relates to multiple contact systems in which at least two movable contact pieces are arranged and fastened transversely to the longitudinal axis of the contact piece carrier in the region of the second, free end of the contact piece carrier. This means that several pairs of contacts can be connected in parallel. In this case, the spring element 18th as a leaf spring with a fastening area 19th and with from this fastening area 19th outgoing separate spring arms 20a , 20b be trained. In the area of the pressure points 24a ; 24b point the spring arms 20a ; 20b each a widened section 29a ; 29b on, which is also referred to below as a spring tongue 29a ; 29b referred to as. Every spring tongue 29a ; 29b is due to a central recess 30a ; 30b essentially ring-shaped. Every spring arm 20a ; 20b has two pressure points 24a ; 24b at opposite positions of the annular spring tongue 29a ; 29b on.

the 4th shows a perspective view of an electrical contact system 2 with two contact pairs 3a , 3b in which the in 3 illustrated spring element 18th is used. A two-contact system is formed in which in the area of the second, free end 12th of the contact piece carrier 7th two movable contact pieces 5a , 5b are arranged and fastened transversely to the longitudinal axis of the contact piece carrier, each with a corresponding fixed contact piece 4a ; 4b a pair of contacts 3a ; 3b form. In the embodiment shown, the contact piece is carrier 7th at least in the end area carrying the contact pieces into two parallel legs 31a , 31b divided up. The recesses 30a , 30b ensure that the pressure points 24a , 24b the spring tongues 29a , 29b not directly on the back of the movable contact piece 5a ; 5b , but on the adjacent area of the contact piece carrier 7th rest because the through the backs of the movable contact pieces 5a , 5b formed protrusions 32a ; 32b through corresponding holes in the contact piece carrier 7th through the contact piece carrier 7th extend therethrough and out of the contact piece carrier 7th protrude within the recesses 30a , 30b condition.

the 5 Figure 11 shows a front view of part of an electrical contact system 2 with two contacts of different sizes. The different sizes of the movable contact pieces require 5a , 5b and their projections formed on the rear side 32a , 32b also different sized spring tongues 29a , 29b and different sized recesses 30a , 30b in the spring arms 20a , 20b .

List of reference symbols

1

Relay, switchgear

2

electrical contact system

3

Contact, contact pair

3a

Contact, contact pair

3b

Contact, contact pair

4th

Contact piece, fixed contact piece

4a

Contact piece, fixed contact piece

4b

Contact piece, fixed contact piece

5

Contact piece, movable contact piece

5a

Contact piece, movable contact piece

5b

Contact piece, movable contact piece

6th

first busbar

7th

Contact piece carrier of the movable contact piece

8th

Current path of the contact piece carrier of the movable contact piece

9

Current path of the contact piece carrier of the movable contact piece

10

Arch section, bead

11

first end of the contact piece carrier of the movable contact piece

12th

second end of the contact piece carrier

13th

second busbar

14th

Armature, lifting magnet

15th

mechanical coupling element, slide

16

lower end of the slide

17th

upper end of the slide

18th

Spring element

19th

Fastening section of the spring element

20th

Spring arm

20a

first spring arm (with two-contact system)

20b

first spring arm (with two-contact system)

21

free end of the spring element

22nd

first spring arm section

23

second spring arm section when the spring element is pretensioned

23 '

second spring arm section when the spring element is not pretensioned

24

Pressure point

24a

Pressure point

24b

Pressure point

25th

frictional connection

26th

Force of the spring element on contact, contact force

27

Current flow

28

Force of the spring element on the armature

29a

first spring tongue, widened section (with two-contact system)

29b

second spring tongue, widened section (with two-contact system)

30a

Recess in the first spring tongue

30b

Recess in the second spring tongue

31a

first leg of the contact piece carrier (with two-contact system)

31b

second leg of the contact piece carrier (with two-contact system)

32a

Protrusion on the back of a first movable contact

32b

Protrusion on the back of a second movable contact

Claims (8)

Switching device (1) with an electrical contact system (2), comprising - at least one contact pair (3) consisting of a fixed contact piece (4) which is attached to a first busbar (6) which is fixed to a housing of the switching device (1), and a contact piece (5) which can be moved relative to the fixed contact piece (4) for a switching function, the contact pieces (4, 5) of the at least one contact pair (3) being positioned relative to one another in such a way that the movable contact piece (5) by means of a contact force (26 ) can be pressed onto the fixed contact piece (4), - a flat contact piece carrier (7) for the at least one movable contact piece (5), which in its longitudinal section along its longitudinal axis from a first end (11) to a second end (12) in It is essentially straight and is attached at the first end (11) to a second busbar (13) which is fixed to the one housing of the switching device (1) and, together with this, a V-shape in longitudinal section forms, wherein the at least one movable contact piece (5) is arranged and fastened in a region of the second end (12) of the contact piece carrier (7), - a spring element (18) without or with lower electrical conductivity and / or with an electrically insulating coating , wherein the spring element (18) is attached to the second busbar (13) and at least one spring arm (20) with a first spring arm section (22) and a second Having spring arm section (23), and wherein the first spring arm section (22) extends from a fastening section (19) to a position with at least one pressure point (24) and the second spring arm section (23) extends from this position to a free end (21 ) of the spring arm (20), and wherein the at least one pressure point (24) is positioned in such a way that a direct or indirect non-positive connection (25) between the pressure point (24) and the movable contact piece ( 5) can be generated and thus a contact force (26) can be generated. Switching device (1) according to Claim 1 , characterized in that the spring element (18) consists of a paramagnetic or optionally a diamagnetic material. Switching device (1) according to Claim 2 , characterized in that the spring element (18) consists of stainless steel or a stainless steel alloy. Switching device (1) according to one of the Claims 1 until 3 , characterized in that the contact system (2) comprises several pairs of contacts (3a, 3b), with several movable contact pieces (5a, 5b) on the contact piece carrier (7) transversely to its longitudinal axis or one behind the other in the direction of the longitudinal axis or transversely to the longitudinal axis, but are arranged offset in the direction of the longitudinal axis. Switching device (1) according to Claim 4 , characterized in that the spring element (18) is designed as a leaf spring with separate spring arms (20a, 20b) for each contact pair (3a, 3b). Switching device (1) according to one of the Claims 1 until 5 , characterized in that the at least one movable contact piece (5a; 5b) extends with a projection formed on its rear side through a corresponding receiving hole in the contact piece carrier (7), and that the at least one spring arm (20a; 20b) in the area of the pressure points ( 24a; 24b) has an annular section (29a; 29b) widened transversely to the longitudinal axis of the contact piece carrier (7) with a central recess (30a; 30b) which is placed in such a way that it rests on the contact piece carrier (7) in the prestressed state and the projection (32a; 32b) formed on the rear side of the movable contact piece (7) is located within the recess (30a; 30b). Switching device (1) according to Claim 6 , characterized in that the at least one spring arm (20a; 20b) has two pressure points (24a; 24b) at opposite positions of the widened annular section (29a; 29b). Switching device (1) according to one of the Claims 1 until 7th , further comprising an excitation coil, an armature (14) and a mechanical coupling element (15) in operative connection with the armature (14), the excitation coil being able to generate a force due to the magnetic field generated by it, which force is generated by means of the armature (14 ) and the mechanical coupling element (15) can be transferred to the contact system (2), so that the contact system (2) can be switched by the excitation coil.

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