Bistable switching device

Abstract

The present invention relates to a bistable switching device (10, 10') for switching an electric circuit between a first position, in which a movable contact arrangement (100, 1100) and a mating contact arrangement (200, 1200) are in a first stable state, and a second position, in which the movable contact arrangement (100, 1100) and the mating contact arrangement (200, 1212, 1214, 1222, 1224) are in a second stable state. The switching device (10) comprising: a drive unit (300) with a motor (310), wherein the drive unit (300) generates a contact normal force in order to press the movable contact arrangement (100, 1100) against the mating contact arrangement (200, 1212, 1214, 1222, 1224) in at least one of the first position and the second position; a transmission unit (400, 1400) arranged between the drive unit (300) and the movable contact arrangement (100, 1100) for moving the movable contact arrangement (100, 1100) between the first position and the second position; wherein the movable contact arrangement (100, 1100) comprises a plurality of contact points (132_1, 132_2), the plurality of contact points (132_1, 132_2) reducing a current density in each of the contact points (132_1, 132_2); and the transmission unit (400) further comprising a mechanical linkage mechanism (410, 420, 430, 1410, 1420, 1430), wherein the mechanical linkage mechanism (410, 420, 430, 1410, 1420, 1430) increases the contact normal force for the sum of the contact points of the plurality of contact points (132_1, 132_2) in at least one of the first position and the second position.

Description

[0001] The invention relates to a bistable switching device, i.e. a switching device which, in contrast to a monostable switching device, has two stable states independent of an external supply.

[0002] A switching device is an electrical component that is used to electric switch circuits on and off. A switching device can be, for example, a disconnecting element, a contactor, a relay or a circuit breaker. In a bistable switching device, a movable contact arrangement and a mating contact arrangement of a first circuit are separated in a first stable position, in this case an open position, and in a second stable position, in this case a closed position, the movable contact arrangement and the mating contact arrangement of the first circuit are electrically conductively connected.

[0003] Additionally, it is possible that the same switching device can be used to switch a second circuit. For example, the movable contact arrangement and a mating contact arrangement of a second circuit are separated in the second stable position, in this case an open position, and in a first stable position, in this case a closed position, the movable contact arrangement and the mating contact arrangement of the second circuit are electrically conductively connected.

[0004] In particular, switching devices can be used for switching high currents and / or high voltages, e.g. several tens of kA or kV. Typically, switching devices with solenoid coil, lifting armature and contact plate are used to switch and interrupt electric circuits in the area of high currents and / or high voltages. They offer very high switching speeds and can interrupt loads of up to several 100 A, but are generally not bistable.

[0005] Switching devices with low contact resistance are advantageous for switching high currents and / or voltages. This is particularly necessary for high short-circuit currents of up to 27 kA and a pulse duration of up to 5 ms. In this case, the high power at the contact point, which generally has the highest contact resistance, leads to damage such as vaporization. In addition, the high short-circuit currents can lead to separation of the contacts, as the effect of magnetic levitation is intensified. As is well known, the current flowing towards the contact point is antiparallel to the current flowing away from the contact point, which leads to repulsion at the contact point. If such an undesirable separation occurs, unwanted arcing can also occur.

[0006] In view of the above, an object of the present invention is creating a bistable switching device that prevents vaporization and the formation of arcs in the event of a short circuit. Further objects are inherited from the special application, namely there may be requirements for the installation space and weight of the switching device.

[0007] The above objects are solved by the subject matter of the independent patent claim. Advantageous further embodiments are the subject of the dependent patent claims.

[0008] A general aspect relates to a bistable switching device for switching an electric circuit between a first position (e.g. an open position of a first circuit and a closed position of a second circuit), in which a movable contact arrangement and a mating contact arrangement are in a first stable state (e.g. separated or electrically conductively connected), and a second position (e.g. an closed position of the first circuit and an open position of the second circuit), in which the movable contact arrangement and the mating contact arrangement are in a second stable state (e.g. separated or electrically conductively connected). The switching device comprises a drive unit with a motor, the drive unit generating a contact normal force to press the movable contact arrangement against the mating contact arrangement in at least one of the first position and the second position, e.g. the closed position of the first circuit or the closed position of the second circuit. The switching device further comprises a transmission unit arranged between the drive unit and the movable contact arrangement to move the movable contact arrangement between the first position and the second position. The movable contact arrangement comprises a plurality of contact points, the plurality of contact points for contacting the mating contact arrangement in the closed position. The plurality of contact points reducing a current density in each of the contact points. The transmission unit further comprises a mechanical linkage mechanism, e.g. a cam mechanism or a lever mechanism, wherein the mechanical linkage mechanism increases the contact normal force for the sum of the contact points of the plurality of contact points in at least one of the first position and the second position, e.g. the closed position of the first circuit or the closed position of the second circuit.

[0009] The contact resistance is reduced by providing the multiple contact points. The mechanical linkage mechanism, e.g. the cam mechanism or the lever mechanism, facilitates to increase the contact normal force to such an extent that the bistable switching device is kept stable, particularly in the closed position of the first or second circuit, and effects such as magnetic levitation in the event of a short circuit or mechanical vibrations, which can promote the separation of the movable contact arrangement from the mating contact arrangement in the closed position of the first or second circuit, are compensated for. At the same time, the mechanical linkage mechanism, e.g. the cam mechanism or the lever mechanism, can meet the requirements for installation space and weight.

[0010] For a better understanding of the present invention, it is explained in more detail with reference to the examples shown in the following figures. The same parts are provided with the same reference signs and the same component designations. In addition, individual features or combinations of features of the various examples shown and described can also represent independent, inventive solutions or solutions according to the invention.

[0011] The present invention will now be described with the aid of the figures.

[0012] It shows: Fig. 1 Sectional view of a switching device according to a first variant in the open position; Fig. 2 Sectional view of the switching device according to the first variant in the closed position; Fig. 3 Schematic view of a part of the drive unit of the switching device according to the first variant; Fig. 4 Schematic view of a circuit for driving the motor of the switching device according to the first variant; Fig. 5 Further schematic view of a part of the drive unit of the switching device according to the first variant; Fig. 6 Schematic view of a part of the transmission unit of the switching device according to the first variant; Fig. 7 Schematic view of a part of Fig. 6; Fig. 8 Schematic view of a contact plate of the switching device according to the first variant; Fig. 9 Schematic view of a mating contact arrangement of the switching device according to the first variant; Fig. 10 Schematic view of a spacer of the switching device according to the first variant; Fig. 11 Schematic detailed view of the inside of the switching device according to the first variant; Fig. 12 Schematic view of the exterior of the switching device according to the first variant; Fig. 13 Further schematic detail view of the interior of the switching device according to the first variant; Fig. 14 Schematic view of a housing of the switching device according to the first variant; Fig. 15 Schematic detailed view of the inside of a switching system using a switching device according to the first variant; Fig. 16 Further schematic detail view of the interior of a switching system using a switching device according to the first variant; Fig. 17 Schematic detailed view of the interior of the switching system according to the first variant; Fig. 18 and 19 Perspective and partly sectional views of a switching device according to a second variant in a position for serial connection; Fig. 20 and 21 Views of the switching device according Figs. 18 and 19 in a position for parallel connection; Fig. 22 to 24 Further views of the switching device according to Fig. 18; Fig. 25 View of a transmission unit of the switching device according the second variant; Fig. 26 and 27 Views of the electrically conducting parts of the switching device according the second variant in a first and second position; and Figs. 28 and 29 Schematic view of a contact plate of the switching device according to the second variant.

[0013] Aspects are described first, with the figures mentioned as examples.

[0014] A first aspect relates to a bistable switching device for switching an electric circuit between a first position (e.g. an open position of a first circuit and a closed position of a second circuit), in which a movable contact arrangement and a mating contact arrangement are in a first stable state (e.g. separated or electrically conductively connected), and a second position (e.g. an closed position of the first circuit and an open position of the second circuit), in which the movable contact arrangement and the mating contact arrangement are in a second stable state (e.g. separated or electrically conductively connected). The switching device comprises a drive unit with a motor, and in particular a reduction transmission. The drive unit generating a contact normal force to press the movable contact arrangement against the mating contact arrangement in at least one of the first position and the second position, e.g. the closed position of the first circuit or closed position of the second circuit. Furthermore, the switching device comprises a transmission unit which is arranged between the drive unit and the movable contact arrangement in order to move the movable contact arrangement between the first position and the second position. The movable contact arrangement comprises a plurality of contact points, the plurality of contact points for contacting the mating contact arrangement. In other words, the plurality of contact points can reduce a current density in each of the contact points. The transmission unit further comprising a mechanical linkage mechanism, e.g. a cam mechanism or a lever mechanism, wherein the mechanical linkage mechanism increases the contact normal force. In particular, the contact normal force is increased for the sum of the contact points of the plurality of contact points in at least one of the first position and the second position, e.g. the closed position of the first circuit or the closed position of the second circuit.

[0015] In this context, bistable means a system that has two stable equilibrium states. Here, the first position and the second position are the two bistable states of the switching device. Figures 1 and 2 show sectional views of the switching device 10 according to a first variant. Fig. 1 shows the switching device in the first position, here the open position. Fig. 2 shows the switching device in the second position, here the closed position. Figs. 18 to 21 show perspective and partly sectional views of the switching device 10' according to a second variant. Figs 18 and 19 show the switch device in a stable position for serial connection, referred to in Fig. 27 and the following as second position. Figs 20 and 21 show the switch device 10' in a stable position for parallel connection, referred to in Fig. 26 and the following as the first position. Notably, the stable position for serial connection can be alternatively referred to as first position and the stable position for parallel connection can be referred to as second position.

[0016] In this context, a drive unit is understood to be a system that has at least one motor. An example of parts of the drive unit is shown in Figures 3 to 5 and in particular in Fig. 24 of the second variant. As shown in particular in Figs. 5 and 24, the drive unit can have a reduction transmission. As shown, the motor can drive a rotating shaft. For example, the motor may be an electric motor such as a DC motor or an AC motor, wherein the motor, in particular the electric motor, usually comprises a rotor driven by a stator. The motor enables the change of states, bi-stability can be generated by the drive unit, e.g. by a suitable motor or other parts of the drive unit or a mechanical self-locking of the transmission unit, for example, a thread with a slider. This makes it possible to maintain each of the two states, in particular the closed state of the parallel connection and / or the closed state of the serial connection, even in the event of a supply interruption, as no holding voltage needs to be provided, such as for a contactor that is operated with a magnetically operated lifting armature. The optional reduction transmission enables the use of smaller motors for the drive unit, which can usually only deliver a low torque. In particular, the reduction transmission increases the torque to such an extent that the contact arrangement can be pressed against the mating contact arrangement with the required clamping force.

[0017] The transmission unit is a unit for transmitting the force supplied by the drive unit, e.g. the torque, to the movable contact arrangement. In particular, the transmission unit can be referred to as a force transmission unit. An example of parts of the transmission unit is shown in Figures 6 to 7 and 23.

[0018] The transmission unit comprises a mechanical linkage. A mechanical linkage transmits and modifies motion and force, converting input into a desired type of output. The mechanical linkage includes in particular cam mechanisms as shown in Figs. 18 to 25 and a lever mechanisms as shown in Figs. 6 and 7.

[0019] Contact resistance is generally understood here as the electrical resistance between the contacts, in particular between the movable contact arrangement and the mating contact arrangement, of the electrical switching device. The contact resistance includes in particular the external layer resistance and the constriction resistance, whereby the external layer resistance is influenced by the contact area. The constriction resistance depends on the effective contact area, which generally restricts the current flow. The constriction resistance depends on the specific resistance of the material used, on surface unevenness (e.g. due to burn-off) and on the number of effective contact areas. The size of the contact points results from the contact normal force and the hardness or firmness of the surface material. A layer resistance results from the specific resistance of the surface and the external layer resistance. The effective contact area results from hardness, roughness and normal force. The constriction resistance results from the effective contact area and the current density.

[0020] The contact resistance is reduced here by increasing the number of effective contact areas by providing the movable contact arrangement with a plurality of n contact points for contacting the mating contact arrangement, where n is an integer greater than or equal to two.

[0021] An example of a movable contact arrangement with a plurality of n contact points is shown in particular in Figs. 8 and 28. Advantageously, n is greater than or equal to 10. Under the approximation that the contact resistance at each contact point is the same, the current density at each contact point is then reduced to 1 / n. This means that in the event of a short circuit, the current density at each contact point is reduced to such an extent that no vaporization occurs. Advantageously, n is less than or equal to 50, as saturation can occur if each contact point has a contact spring. A normal force is determined by the spring deflection. However, the possible spring force becomes smaller and weaker as the number of contact points increases. However, contact springs with a weaker spring force then lead to a limitation of the total resistance. An upper limit on the number of contact springs can therefore be useful.

[0022] In addition, the spring travel leads to a relative movement of the contact point on the mating contact area, which leads to a reduction in the external layer resistance. This desired effect is also known as contact fritting.

[0023] The transmission unit is equipped with a mechanical linkage such as a cam mechanism as in particular shown in Figs 18 to 25 or a lever mechanism as in particular shown in Figs. 1 and. Acam mechanism is a mechanical system that converts rotary motion into linear motion. It typically comprises three main components. A first component is a cam 1420, which is a rotating or sliding part that has an irregular shape. As it turns or moves, it makes contact with and pushes against another a second component, here a cam follower 1122 shown in Fig. 25, transmitting motion. The cam follower 1122 makes direct contact with the cam 1420 and follows its contour. The movement of the follower 1122 can be translational (linear), in particular between as here between the first position and the second position. A third component is a camshaft 1420, on which the cam 1410 is mounted, providing the rotational movement needed for the cam's 1410 operation. A lever mechanism is a basic mechanical device used to transmit and amplify a force via a lever arm. Notably, a cam mechanism can function similarly to a lever mechanism in the way it transmits and amplifies force to move the follower 1122. Herein, the mechanical linkage, e.g. the cam mechanism and / or the lever mechanism, increases the contact normal force for each of the multiple contact points in at least one of the first and second position, e.g. the closed position of a first circuit and / or the closed position of a second circuit. For example, if a spring contact is used, each contact spring can be deflected by greater than or equal to 0.2 mm and / or less than or equal to 0.4 mm, in particular 0.3 mm. The spring constant results in a normal force of 3-5N per spring. The spring travel can be limited by a lateral protective structure, which is described later as an end stop. This limits the normal force for all spring contacts, regardless of how much force the mechanical linkage, e.g. the cam mechanism and / or the lever mechanism applies. For example, the mechanical linkage, e.g. the cam mechanism and / or the lever mechanism, only needs to exceed the minimum dimension n x 3-5N. This transmission and amplification is achieved mechanically by the linkage mechanism and can be described by using the lever law. A large lever force (also referred to as output force) is provided at the movable contact arrangement, which makes it possible that even at high short-circuit currents the effects of magnetic levitation do not lead to separation. The levitation depends on the number of contact points. In the constriction resistance there are opposing Lorenz forces that lead to repulsion of the contact points and thus levitation. The Lorenz forces increase with the square of the current density. By reducing the current density in each of the contact points, the effect of levitation is reduced. A small leverage force (also referred to as input force) is transmitted to the drive unit, which allows the minimum amount of force transmission, for example n x 3-5 N, to be reduced. This enables the switching device to be manufactured with a smaller and lighter weight. In other words, the input force is smaller than the output force.

[0024] A second aspect relates to the switching device according to aspect 1, wherein the stable contact arrangement comprises, as for example shown in Figs. 26 and 27, a first pair of contact terminals 1212 and 1214 of a first power-and-load-element and a second pair of contact terminals 1222 and 1224 of a second power-and-load-element, wherein, the mechanical linkage mechanism connects the two power-and-load-elements in parallel in the first position, as shown in Fig. 26, and connects the two power-and-load-elements in series in the second position, as shown in Fig. 27.

[0025] For example, as used herein, the power-and-load-element is a power source such as battery or a battery package comprising a plurality of cells. Alternatively or additionally, the power-and-load-element is a power load such as a motor. Sometimes, the motor may act as a power source, in other words operating as generator, and the battery may act in such a situation as a load, e.g. when charging. The power-and-load-element are connected to a power distribution system for example by bus bars comprising the contact terminals 1212, 1214, 1222, and 1224.

[0026] For simplicity, in the following the battery is assumed to be operated as power source. In particular, the battery can comprise a plurality of sub units, for example a first DC power source that has the contact terminals 1212 and 1214 and a second DC power source that has the contact terminals 1222 and 1224. Each power source is connected by the power distribution system with terminals. For example, two terminals are at a high potential, e.g. positive terminals at +400 V, e.g. terminals 1212 and 1214 and the contact terminals 1214 and 1224 are terminals at a low potential, e.g. negative or ground terminals at 0 V. By the switching device, the power distribution system can be switched between serial connection and the parallel connection. Thus, the switching device facilitates for example to double the output voltage, e.g. being 800 V, in serial connection and to double the current output in the parallel connection. This switching system can therefore be used, for example in a vehicle, to enable a voltage of 400 V for charging a battery and a voltage of 800 V for driving the vehicle.

[0027] The switching device according to the second variant further facilitates, compared to the switching device according to the first variant shown in Figs. 15 to 17 and to be described later, that one single drive unit and one single transmission unit can be used to switch between serial and parallel connection. Further, this configuration reduces the number of bridge contacts from 4 to 3 and bus bars from 5 to 4 compared to the solution shown in Figs. 15 to 17. Further, the number of contact areas is reduced from 8 to 6. Further, in the serial path, the resistance can be reduced in view of the reduced number of switching contacts.

[0028] A third aspect relates to the switching device according to any one of the preceding aspects, wherein the stable contact arrangement comprises a plurality of terminals, wherein at least one of the terminals comprises a first contact area for contacting the movable contact arrangement in the first position and the at least one terminal comprises a second contact area opposing the first contact area for contacting the movable contact arrangement in the second position.

[0029] As shown in Figs. 26 and 27, the terminals 1214 and 1222 are formed as a metallic stripes or bars used for conducting electricity within a power distribution system. In other words, the terminals are a part of a bus bar. For example, the terminal 1214 has contact area 1214_1 for parallel connection and at an opposing side a contact area 1214:2 for serial connection. Thus, the two opposing contact areas facilitate switching by the movable contact arrangement comprising bridges 1110_1, 1110_2, and 1110_3 the power distribution system in the first position in parallel connection and in the second position for serial connection. A fourth aspect relates to the switching device according to any one of the proceeding aspects, wherein the motor, in particular a DC motor, comprises a rotor for driving a drive shaft extending in the axial direction, and the drive unit comprises a reduction transmission and an output shaft extending in the axial direction, which is driven by the reduction transmission, wherein the output shaft and the rotor of the motor are arranged side by side.

[0030] Side by side here means arranged at a distance in a radial direction perpendicular to the axial direction. In other words, arranged side by side here means independent of a circumferential direction. The drive shaft is therefore located above or below the output shaft, for example. This enables a compact arrangement.

[0031] In addition or as an alternative to the arrangement of the output shaft next to the drive shaft, the switching device can have a circuit board with a circuit for driving the motor, which is arranged at an axial end of the motor. This also contributes to the compact arrangement.

[0032] In addition or as an alternative to the arrangement of the output shaft next to the drive shaft, the drive unit can have a limiting device. In particular, this can detect when the first or second position is reached and the motor can be controlled accordingly, e.g. switched off. For example, the limiting device can comprise a position element for limiting the movement of the transmission unit. Additionally or alternatively, the limiting device can control the motor on the basis of the power consumed by the motor. When the power consumed by the motor is greater than a limit power, a control unit may determine that a limiting device has been reached. Additionally or alternatively, a limit switch may be provided to inform a control unit that a limiting device has been reached. Additionally or alternatively, the control unit may be provided with predetermined values to stop the drive unit that a limit has been reached. Thus, the cam mechanism may be restricted to rotate the cam by only 180°, so that the device is hold in any of the stable positions. It should be understood that the value of 180° may be provided with some tolerances, for example 180°+- 15°.

[0033] A fifth aspect relates to the switching device according to one of the previous aspects, wherein the drive unit has a reduction transmission with a gear transmission, wherein the gear transmission is arranged between a drive shaft of the motor and an output shaft of the drive unit. This arrangement enables a space-saving and stable solution. Alternative solutions would be chain or planetary gears.

[0034] A sixth aspect relates to the switching device according to any one of the preceding aspects, wherein the mechanical linkage mechanism comprises a cam mechanism comprising a cam shaft rotated by an output shaft of the drive unit and a cam for converting the rotational movement of the cam shaft for reciprocating movement between the first position and the second position. This solution is particular shown in Fig. 24. The cam shaft 1410 comprises the cam 1420. Notably, to reduce integration space, the output shaft 340 and the cam shaft 1410 can be arranged next to one another.

[0035] A seventh aspect relates to the switching device according to aspect 6, wherein the cam mechanism comprises a driving wheel rotated by the drive unit and wherein the driving wheel and the cam form a reduction transmission for increasing the contact normal force. The driving wheel 1430 is in particularly shown in Fig. 24 and has a larger outer diameter than the diameter of a circle enclosing the movement of the irregular shaped cam 1420.

[0036] Advantageously, as shown in Fig. 24, the cam mechanism further comprises a gear transmission, wherein the gear transmission is arranged between the output shaft 340 of the drive unit and the drive wheel 1430 of the cam mechanism. In particular, the drive wheel 1430 is a gear and the output shaft 340 comprises a gear, in particular is formed as a gear.

[0037] An eighth aspect relates to the switching device according to any one of the preceding aspects, wherein the mechanical linkage mechanism comprises a contact bridge holder for moving at least one contact bridge between the first position and the second position. In particular, a contact bridge holder 1120 is shown in Fig. 25. This contact bride holder 1120 can move in particular a plurality of for example three contact bridges 1110_1, 1110_2, and 1110_3. The contact bridge holder 1120 can be made of an isolating material, for example plastic. Further, the contact bridge holder 1120 can be assembled from two parts, namely a first contact bridge holder 1120_1 for holding a first bridge 1110_1 and a second contact bridge holder 1120_2 for holding second bridges 1110_2 and 1110_3.

[0038] A ninth aspect relates to the switching device according to aspects 6 or 7 and aspect 8, wherein the contact bridge holder comprises at least one cam follower for following the reciprocate movement of the cam. In particular, the contact bridge holder 1120 shown in Fig. 25 comprises the elongated recesses 1122 that form cam followers.

[0039] A tenth aspect relates to the switching device according to any one of aspects 8 to 9, wherein the switching device comprises a linear guide for guiding a slider of the contact bridge holder. In particular, the contact bridge holder 1120 shown in Fig. 25 comprises a protrusion at reference numeral 1120_2 forming a slider and a not showing housing of the switching device can comprise a receiving guide.

[0040] An eleventh aspect relates to the switching device according to any one of the preceding aspects, wherein the mechanical linkage mechanism comprises: at least one first contact bridge for parallel connection of two power-and-load-elements in the first position; and a second contact bridge for serial connecting of the two power-and-load elements in the second position. As discussed with Figs. 26 and 27, the contact bridges 1110_2 and 1110_3 facilitate parallel connection of the two power-and-load-elements and the contact bridge 1110_1 facilitates a seral connection of the two power-and-load-elements.

[0041] A twelfth aspect relates to the switching device according to any of aspects 8 to 10 and aspect 11, as shown in Fig. 25, the first contact bridges 1110_2 and 1110_3 and the second contact bridge 1110_1 are hold by the contact bridge holder 1120.

[0042] A thirteenth aspect relates to the switching device according to any of aspects 11 to 12, wherein at least one contact bridge is formed from a one-side coated metal bar. The coating can in particular comprise silver.

[0043] As used herein, a one-sided coated metal bar or band for an electrical bridge contact can be manufactured using different methods, especially when aiming to increase the conductivity of the coated side while using an economic base material such as aluminum. For example, roll coating or continuous line coating is an efficient method, where the bar or band passes through a system that applies a conductive coating to only the desired side. This is more economic than a selective process for selecting one side. This one-sided coating approach offers numerous advantages for electrical bridge contacts, particularly when the coated side is designed to enhance conductivity. The use of aluminum as the base material enables a lightweight and cost-effective solution, while the applied conductive coating on one side enables to improve the electrical performance of the component. This allows current to flow more efficiently through the coated side, making it ideal for applications that require reliable electrical connections. The selective application of the conductive coating reduces material usage and production costs compared to fully coating both sides. The uncoated side retains its properties for structural or non-conductive functions, providing design flexibility without altering the overall function of the band. This setup also facilitates to enhance the durability and lifespan of the metal band, especially in demanding conditions where the coated side requires higher conductivity and protection. The result is a tailored solution that facilitates to combine the benefits of for example aluminum's lightweight properties with an enhanced conductive surface, making it suitable for applications where both high performance and cost-efficiency are desired.

[0044] A fourteenth aspect relates to the switching device according to any of the preceding aspects, further comprising a contact plate, wherein each of the contact points of the plurality of contact points is formed by a spring element of the contact plate. An example of such a contact plate is shown in Figs. 8 and 28. The contact plate is preferably arranged on the stable contact arrangement as shown in Figs. 26, 27, and 28. This is particular advantageous in case the mechanical linkage mechanism comprises the cam mechanism. Additionally or alternatively, the contact plate is arranged on the movable contact arrangement, for example in case the mechanical linkage mechanism comprises the lever mechanism. Notably, the contact plate can also be formed additionally or alternatively on the mating contact arrangement. A spring element enables a reliable and repeatable connection between the two contact points due to its elastic properties. In particular, spring elements are moved by the mechanical actuation of the switching device, in this case the movable contact arrangement. When the switching device is actuated, the movable contact arrangement presses on each of the spring elements, compressing them and making contact. The elastic properties of the spring elements allow them to return to their original position after actuation. This ensures that contact is only made when the switching device is actuated and is released again when actuation ceases. As explained above, a contact normal force of 3-5N per spring, for example, can act on the tensioned spring. In the open position, the contact springs do not make contact with the mating contact arrangement. Each spring element exerts a certain force to maintain contact. This force must be strong enough to ensure reliable electrical contact, but not too strong to avoid excessive wear or breakage of the contact areas. In particular, the contact plate can include at least one end stop to prevent overstretching of the spring element. To increase the conductive, the contact plate can be coated with a coating comprising at least one of silver and tin.

[0045] A fifteenth aspect relates to the switching device according to any one of aspects 2 and 3 and aspect 14, wherein at least one of the terminals comprises the contact plate. According to this solution, which is for example shown in Fig. 29, the contact terminal 1110, which is part of the power distribution system connected to the power-and-load-element, comprises the contact plate. In other words, the contact terminals 1110 can be seen as terminals of bus bars. The thermal heat is predominantly created in the contact plate 130. This heat is efficiently transferred by thermal conduction via the terminal 1110 to the not shown bus bar. This not shown bus bar is connected to the external of the switching device, as for example shown in Fig. 22. Thus, this arrangement facilitates to efficiently transfer heat generated in the device away from the device by using the bus bars of the power supply system and connecting the contact plates 130 to the power distribution system and not to bridges in the switch.

[0046] A sixteenth aspect relates to the switching device according to any of the previous aspects, wherein the transmission unit further comprises a linear guide comprising a guide element and a slider, wherein the slider is guided by the guide element to move the transmission unit between the open position and the closed position. Advantageously, the guide element has a limiting device to stop the movement of the slider. As shown in Figures 1 and 2, the guide element can be formed by the drive unit, in this case the output shaft. Alternatively, the guide element can be provided on the movable contact arrangement according to an embodiment not shown. A linear guide enables a space-saving conversion of a rotary movement of the motor into a linear movement.

[0047] A seventeenth aspect relates to the switching device in particular according to aspect 16, wherein a linear guide comprises a screw spindle as a guide element to move the slider in an axial direction along the screw spindle. A screw spindle is a type of spindle used to convert rotational movements into linear movements with high accuracy. In addition, the limiting device described above can be realized with a screw spindle of defined length. The self-locking of the spindle can contribute to the bi-stability of the arrangement. This can be additionally supported by exceeding the dead center of the lever arrangement, whereby the dead center is reached when all hinge rods are in line. The dead center can therefore represent a further stable position in which the normal forces are at a maximum and the restoring forces on the spindle are at a minimum. Finally, the force applied can be adjusted via the pitch of the spindle.

[0048] An eighteenth aspect relates to the switching device in particular according to aspect 17, wherein the linear guide comprises two screw spindles and two sliders, wherein both screw spindles are arranged on an output shaft of the drive unit, in particular wherein the screw spindles have different pitch directions in order to move the sliders in opposite directions in the axial direction. Two spindles distribute the power transmission to the output shaft. Different pitch directions lead to symmetrical forces in the axial direction, which reduce the material stress on the output shaft. In other words, the forces are in equilibrium within the spindle, which means that no bending moments or displacement forces are transmitted to the bearings.

[0049] A nineteenth aspect relates to the switching device according to one of the preceding aspects, wherein the movable contact arrangement comprises a contact bridge with two contact fields for double contacting, in particular interrupting, the electric circuit, wherein each of the contact fields comprises at least one contact point of the plurality of contact points. Advantageously, each of the contact fields has a plurality of contact points. In particular, the double interruption results in improved dielectric strength. A contact bridge enables a particularly stable solution, as two connections can be attached to the mating contact arrangement. In this case, it is not absolutely necessary to arrange a connection on the movable contact arrangement, but it is possible.

[0050] An twentieth aspect relates to the switching device according to one of the preceding aspects, wherein the movable contact arrangement comprises two opposing contact areas for double contacting, in particular connecting, the electric circuit, each of the contact areas comprising at least one contact point of the plurality of contact points. Advantageously, each of the contact areas has a plurality of contact points. Opposite contact fields enable a symmetrical arrangement. This allows the lever forces to be transmitted symmetrically to the radial direction to the drive unit, in particular the output shaft.

[0051] A twenty-first aspect relates to the switching device according to one of the preceding aspects, wherein the lever mechanism further comprises an articulated rod. The rod is connected to the drive unit via a drive unit joint and to the movable contact arrangement via a contact arrangement joint. The rod is a rigid element that forms the lever. The two joints are the pivot points of the lever mechanism. The input force exerted on the lever to move the lever is applied to the joint of the drive unit. The output force is transmitted to the movable contact arrangement at the joint of the contact arrangement. The solution with joints is a particularly space-saving solution.

[0052] Attached here means that the joint is attached to a second element, in this case the movable contact arrangement or the drive unit. In particular, the drive unit joint is attached to the drive unit via a slider and a guide element of the transmission unit in particular according to one of aspects 16 to 18. In other words, the drive unit joint is attached to the drive unit so as to be movable in the axial direction. Furthermore, the contact arrangement joint is arranged in particular immovably on the movable contact arrangement. This allows a small input force to be applied to the slider over a large path length in the axial direction to produce a large output force over a small path length at the contact arrangement joint.

[0053] A twenty-second aspect relates to the switching device in particular according to aspect 21, wherein the lever mechanism further comprises a second articulated rod, the second articulated rod being connected to the drive unit via a second drive unit joint and to the movable contact arrangement via a second contact arrangement joint. For the description of the second articulated rod, it is referred to the above description of the first articulated rod. Two rods make it possible to transmit forces symmetrically to the drive unit, in particular the output shaft, i.e. symmetrically in the axial direction or in the radial direction, in particular in order to transmit two opposing amounts of force.

[0054] For example, the first drive unit joint and the second drive unit joint are connected to the drive unit via a slider and a guide element of the transmission unit in particular according to one of aspects 16 to 17. This enables the transmission of forces of opposite magnitude in the radial direction to the drive unit, in particular to the output shaft. Such an arrangement is similar to a knee joint, whereby the lever arms of the knee joint are of equal length. This solution in particular makes it easy to create a bistable switching device.

[0055] Alternatively, the first drive unit joint is connected to the drive unit via a first slider and the second drive unit joint is connected to the drive unit via a second slider and a guide element of the transmission unit in particular according to aspect 18 is connected to the drive unit. This enables the transmission of forces of opposite magnitude in the axial direction to the drive unit, in particular to the output shaft.

[0056] Advantageously, the movable contact arrangement has a contact bridge in particular according to aspect 19 and the first contact arrangement joint is connected to the first contact field and the second contact arrangement joint is connected to the second contact field of the movable contact arrangement. This makes it possible to transmit a double output force in the radial direction to the movable contact arrangement while compensating for the axial forces acting on the drive unit.

[0057] Alternatively, the movable contact arrangement has two opposing contact areas in particular according to aspect 20 and the first contact arrangement joint is connected to the first contact area and the second contact arrangement joint is connected to the second contact area of the movable contact arrangement. This makes it possible to transmit a double output force in the radial direction to the movable contact arrangement while supporting the radial forces acting on the drive unit.

[0058] An twenty-third aspect relates to the switching device in particular according to aspect 22, wherein the lever mechanism further comprises a third articulated rod, wherein the third articulated rod is connected to the drive unit via a third drive unit joint and to the movable contact arrangement via a third contact arrangement joint. For the description of the third articulated rod, it is referred to the above description of the first and second articulated rods. Three rods enable the symmetrical transmission of forces to the drive unit, in particular the output shaft. This means that force can be transmitted symmetrically in the axial direction and / or in the radial direction.

[0059] A twenty-fourth aspect relates to the switching device in particular according to aspects 18, 19, 20 and 23, wherein the lever mechanism further comprises a fourth articulated rod, wherein the fourth articulated rod is connected to the drive unit via a fourth drive unit joint and to the movable contact arrangement via a fourth contact arrangement joint. For the description of the fourth articulated rod, it is referred to the above description of the first to third articulated rods. Four rods enable the symmetrical transmission of forces to the drive unit in the axial and radial directions.

[0060] The first drive unit joint and the second drive unit joint of the twenty-fourth aspect are connected to the drive unit via the first slider and the first screw spindle. This makes it possible to balance radial forces on the output shaft.

[0061] The third drive unit joint and the fourth drive unit joint of the twenty-fourth aspect are connected to the drive unit via the second slider and the second screw spindle. This enables axial forces on the output shaft to be balanced.

[0062] The movable contact arrangement of the twenty-fourth aspect has two opposing contact areas in particular according to aspect 20, wherein each of the contact areas forms a contact bridge in particular according to aspect 19. Furthermore, the first and third contact arrangement joints are connected to the first contact bridge and the second and fourth contact arrangement joints are connected to the second contact bridge. In particular, this solution makes it possible to reinforce the advantages described above.

[0063] A twenty-fifth aspect relates to the switching device according to one of the preceding aspects, wherein the mating contact arrangement comprises at least one arcuate clamping contact element with two opposing mating contact areas electrically connected in the open position for double connection of the electric circuit. In particular, the mating contact arrangement can have two arcuate clamping contact elements that are separated in the open position. An example of such a clamping contact element is shown in Fig. 9. In other words, the mating contact arrangement comprises a bridge part and two legs, which are arranged in a U-shape. A connection can be provided on a bridge part in order to connect the switching device to the electric circuit to be switched. The legs are opposite each other and can exert a counterforce on the movable contact arrangement.

[0064] A twenty-sixth aspect relates to a switching system comprising at least one switching device according to any one of aspects 1 to 25 and for mechanically switching a second electric circuit between an open position, in which a second movable contact arrangement and the mating contact arrangement are disconnected, and a closed position, in which the second movable contact arrangement and the mating contact arrangement are electrically conductively connected. The switching system comprises a second transmission unit which is arranged between the drive unit and the movable second contact arrangement in order to move the second movable contact arrangement between the open position and the closed position. The second movable contact arrangement has a second plurality of contact points for contacting the mating contact arrangement, the second plurality of contact points reducing a current density in each of the contact points of the second plurality; and the second transmission unit further has a second lever mechanism, the lever mechanism increasing the clamping force for each of the contact points of the plurality of second contact points in the closed position. An example of such an arrangement is shown in Fig. 17. A second movable contact arrangement enables the first and second electric circuits to be connected in parallel or in series. In particular, it is possible to connect two electric circuits in parallel and one electric circuit in series. This switching system can therefore be used, for example in a vehicle, to enable a voltage of 400 V for charging a battery and a voltage of 800 V for driving the vehicle.

[0065] For the description of the second movable contact arrangement, reference is made to the above description of the first movable contact arrangement. For the description of the second transmission unit, reference is made to the above description of the first transmission unit. For the description of the second plurality of contact points, reference is made to the above description of the first plurality of contact points. For the description of the second lever mechanism, reference is made to the above description of the first lever mechanism.

[0066] In particular, the switching system may further comprise a second drive unit with a second motor and a second reduction transmission, wherein the second drive unit generates a clamping force to press the second movable contact arrangement against the mating contact arrangement in the closed position. An example of such an arrangement is shown in figures 15 and 16. For the description of the second drive unit, reference is made to the above description of the first drive unit.

[0067] The figures have only been described as examples so far and are described in detail below to show further detailed aspects. The switch 10 according to the first variant is described in particular with reference to Figs. 1 to 17. The switch 10' according to the second variant is described in particular with reference to Figs. 18 to 29. Some of the parts are only described with reference to one of the switches 10, 10' but may be equally used for the other variant.

[0068] Figure 1 shows a bistable switching device according to the first variant for switching an electric circuit not shown, the switching device being in an open position in which a movable contact arrangement 100 and a mating contact arrangement 200 are separated. Figure 2 shows the bistable switching device 10 in a closed position, in which the movable contact arrangement 100 and the mating contact arrangement 200 are electrically conductively connected.

[0069] Figs 18 and 19 similarly show a bistable switching device 10' according to the second variant for switching terminals of a not shown electric circuit, e.g. a power distribution system, the switching device being in a first position in which a movable contact arrangement and a mating contact arrangement switch power-and-load-elements connected to the electric circuit to be connected in series. Figs. 20 and 21 show the bistable switching device 10' according to the second variant in a second position, in which the movable contact arrangement and the mating contact arrangement switch power-and-load-elements connected to the electric circuit to be connected parallel.

[0070] The switching devices 10, 10' comprise a drive unit 300, which is shown in particular in Figures 3 to 5 and for example Fig. 23. The drive unit comprises a motor 310. The drive unit generates a contact normal force to push the movable contact arrangement 100, e.g. the bridges 110 and / or 1110, against the mating contact arrangement 200, e.g. clamping contact element 210_a, 210_b or terminals 1212, 1214, 1222, 1224, in the closed position of parallel and(or serial connection. The 310 motor can be a direct current motor, which has a rotor in a housing for driving a drive shaft 320 extending in axial direction A.

[0071] The drive unit 300 can also have a reduction transmission 330. The reduction transmission 330 drives an output shaft 340 extending in axial direction A, as can be clearly seen in Figs. 1 and 23, for example. As shown in particular in Figs. 5 and 23, the drive unit 300 has a reduction transmission 330 with a gear transmission, wherein the gear transmission is arranged between a drive shaft 320 of the motor 310 and an output shaft 340 of the drive unit 300. Here, the gear transmission has a first gear 332 and a second gear 334. In particular, the output shaft 340 and the rotor of the motor are arranged next to each other.

[0072] The drive unit 300 may further comprise a printed circuit board 350 shown in Figs. 4 and 23 having a circuit for driving the motor 310. As shown in Fig. 3, a bottom housing portion 22 of the switching device 100 may provide a receptacle to hold the drive unit 300. Similarly, the switching device according to the second variant in Figs 18 to 24 may comprises a not shown bottom housing portion. Thus, the circuit board 350 may be disposed at one axial end of the motor 310. At an opposite axial end of the motor 310, a reduction transmission guide 24 (not shown in Figs 18 to 24) may be provided to hold the reduction transmission 330. This arrangement enables the gearwheel 334 to be mounted on the bottom housing portion 22 in a particularly stable and space-saving manner.

[0073] The switching devices 10, 10' further comprise a transmission unit. A transmission unit 400 according to the first variant is shown in particular in Figures 6 to 8. A transmission unit 1400 according to the second variant is shown in particular in Figs. 23 to 27. The transmission unit 400 and / or 1400, which is arranged between the drive unit 300 and the movable contact arrangement 100, 1100, makes it possible to move the movable contact arrangement 100, 1100 between the first position and the second position.

[0074] The transmission unit further comprises mechanical linkage mechanism, e.g. a cam mechanism or a lever mechanism, wherein the mechanical linkage mechanism increases the contact normal force for each of the plurality of contact points in the closed position.

[0075] A first variant of a mechanical linkage mechanism is shown in particular in Fig. 1. The mechanical linkage mechanism comprises the lever mechanism. The lever mechanism comprises four articulated rods 410_1 to 410_4, four drive unit joints 420_1 to 420_4 and four contact arrangement joints 430_1 to 430_4. Each of the rods 410 is connected to the drive unit 300, in this case the output shaft 340, via a drive unit joint 420 and to the movable contact arrangement 100 via a contact arrangement joint 430. For simplicity, the first variant of the mechanical linkage mechanism is described in connection with the first switching device and the second variant of the mechanical linkage mechanism is described in connection with the second switching device. Even if not shown, the first variant of the mechanical linkage mechanism can be implemented in the second switching device and the second variant of the mechanical linkage mechanism can be implemented in the first switching device.

[0076] Further, the transmission unit 400 of the first variant has a linear guide 440 with a guide element 442 and two sliders 444_1, 444_2, wherein the sliders 444_1, 444_2 are guided by the guide element 442 to move the transmission unit 400 between the open position and the closed position.

[0077] As shown in Fig. 1, the linear guide 440 has two screw spindles 443_1, 443_2 as guide element 442 in order to move the sliders 444_1, 444_2 in the axial direction A along the screw spindles 443_1, 443_2. The screw spindles can have different pitch directions in order to move the sliders 444_1, 444_2 in opposite directions in the axial direction A, as shown in Fig. 2, for example.

[0078] As shown in Fig. 1, the first drive unit joint 420_1 and the second drive unit joint 420_1 are connected to the drive unit 300 via the first slider 444_1 and the first screw spindle 443_1. Furthermore, the third drive unit joint 420_3 and the fourth drive unit joint 420_4 are connected to the drive unit 300 via the second slider 444_2 and the second screw spindle 443_2.

[0079] The second variant of the mechanical linkage mechanism, as shown in particular in Fig. 23, comprises the cam mechanism. The cam mechanism comprises a cam shaft 1410, a cam 1420, a drive wheel 1430 and a cam follower 11222 formed at a contact bridge holder 1120. Further, the contact bridge holder 1120 comprises a slider 1120_2 for being guided in a liner guide formed for example at a housing part of the switching device.

[0080] In more detail, the drive wheel 1430 is attached to the cam shaft 1410. The drive wheel 1430 is rotated by the output shaft 340 of the drive unit 300. In particular, as shown in Fig. 24, the output shaft 340 forms a first gear and the drive wheel 1430 forms a second gear, and thus, the both form a gear transmission with increasing torque.

[0081] Further, to facilitate equal load distribution, two cams 1420 are attached to the cam 1410. Each cam 1420 is received by a cam follower 1122 as shown in Fig. 24. As in particular shown in Fig. 25, each of the cam followers 1122 is formed as a recess in the contact bridge holder 1120. Further, to guide the reciprocate movement of the contact bridge holder 1120, sliders 1120_2 are formed on the contact bridge holder 1120, the sliders being guided by not shown linear guides of the switching device. The movable contact arrangement 100, 1100 has a plurality of contact points for contacting the mating contact arrangement 200, the plurality of contact points reducing a current density in each of the contact points.

[0082] A first variant of the movable contact arrangement 100is shown in particular in Fig. 6. This movable contact arrangement 100 has two contact bridges 110_1, 110_2, wherein each of the contact bridges 110 has two contact fields 120_1a, 120_1b, 120_2a, 120_2b. Each of the contact fields 120_1a, 120_1b, 120_2a, 120_2b has at least one contact point of the plurality of contact points.

[0083] As further shown in Fig. 6, the pair of contact fields 120_1a and 120_2a and the pair of contact fields 120_1b and 120_2b each form two opposing contact areas for double contacting, in particular connecting, the electric circuit.

[0084] A second variant of the movable contact arrangement 1100 is shown in particular in Figs. 25 to 28. This movable contact arrangement 100 comprises a first contact bridge 1110_1 and two second contact bridges 1110_2 and 110_3, wherein each of the contact bridges comprises two contact fields. Each of the contact fields comprises a plurality of contact points when contacting with the stable contact arrangement.

[0085] According to the first variant of the movable contact arrangement 100, each of the contact fields 120_1a, 120_1b, 120_2a, 120_2b has a plurality of contact points. In particular, each of the contact fields 120_1a, 120_1b, 120_2a, 120_2b can be provided with a contact plate 130.

[0086] According to the second variant of the movable contact arrangement 1100, each of contact fields of the stable contact arrangement comprises a plurality of contact points. In particular, each of the contact fields can be provided with a contact plate 130.

[0087] Fig. 8 shows a contact bridge 110 with two contact plates 130. Figs 26, 27 and 29 shows a terminal 1110 of the stable contact arrangement with the contact plate 130. For example, at each of terminals 1214 and 1222 two contact plates 130 are arranged and at each of terminals 1212 and 1224 one contact plate is arranged. Fig 29 shows in detail the arrangement of a contact plate 130 on the terminal 1110.

[0088] In particular, the contact plate 130, as shown in Figs. 8 and 28, has a plurality of more than ten contact points, which are formed by spring elements 132_1, 132_2 of the contact plate 130. For example, the contact plate 130 can be formed as a stamped and bent part. Furthermore, the contact plate 130 can comprise end stops 134_1, 134_2 to prevent overstretching of spring elements 132_1, 132_2. In particular, the end stops are provided at corners of the contact plate.

[0089] According to the first variant, as shown in particular in Fig. 1 and Fig. 7, the first and third contact arrangement joints 430_1, 430_3 are connected to the first contact bridge 110_1 and the second and fourth contact arrangement joints 430_2, 430_4 are connected to the second contact bridge 110_2. This symmetric arrangement of two bridges moving in opposing directions between the open and closed position facilitates symmetrical load distribution and doubling the contact points.

[0090] Alternatively, as discussed in the second variant, it is possible to move only one of the contact bridges to connect two terminals.

[0091] The mating contact arrangement according to the first variant is shown in particular in Figures 9 to 11. The mating contact arrangement 200 can comprise two arcuate clamping contact elements 210_a, 210_b. Each of the clamping contact elements 210_a, 210_b comprises two opposing mating contact areas 220_1a, 220_2a and 220_1b, 220_2b, which are electrically connected in the open position, for double connection of the electric circuit. Furthermore, each of the clamping contact elements 210_a, 210_b comprises a terminal 230_a, 230_b. This arrangement therefore makes it possible to interrupt an electric circuit. The arcuate clamping contact is chosen in view of two bridges moving in opposing directions between the open and closed position. Alternatively, as shown in the second variant, when moving a contact bridge only in one direction, the terminals may be provided as not bended bus bars. Bending a bus bar comes at the expense of costs and considering tolerances. The second variant, which does not require bending contacts, thus may facilitate to increase precision and may reduce manufacturing costs.

[0092] A contact element guide element 240 according to the first variant is shown in Fig. 10. This guide element 240 is mounted receiving a part of the output shaft 340 of the drive unit 300 and guides the movable contact elements 100 in linear movement. The perpendicular arrangement to the axis of rotation of the drive unit 300 and to the mating contact arrangement 200 enables that the movable contact arrangement 100 is positioned parallel to the mating contact arrangement 200.

[0093] A slider 1122 according to the second variant is shown in Fig. 25. This slider 1122 is formed at the contact bridge holder 1100 and is received by a not shown linear guide of the switching device and guides the movable contact elements 1100 in linear movement.

[0094] The switching device according to the first variant with mating contact arrangement 200 and movable contact arrangement 100 is shown in Fig. 11. In particular, the switching device can have a cover housing portion 30 in addition to the bottom housing portion 22, as shown in Fig. 14. In the assembled state, which is shown in particular in Fig. 12, the cover housing portion 30 with the bottom housing portion protect the electrical and movable components of the switching device from external influences.

[0095] Even not shown in the Figures, the switching device according to the second variant may comprise a similar housing part as shown in with regard to the first variant. Further details of the switching device according to the first variant are shown in Fig. 13, in particular the arrangement of the separating element 240, which is partially received in a recess in the movable contact arrangement in order to guide it in.

[0096] Furthermore, Figures 15 to 17 show a switching system according to a first variant with at least parts of the switching device 10 according to the first variant described above. In particular, the switching system enables mechanical switching of a second electric circuit between an open position and a closed position. Here, the switching system has four terminals 232_a, 232_b, 232_c and 232_d. The terminals 232_a and 232_b can be connected by a first movable contact arrangement 100. In contrast to the mating contact arrangement 200 described above, opposite mating contact areas are not connected here. The terminals 232_a and 232_c can be connected via an additional connecting conductor 250 by means of a second movable contact arrangement 100'. Like the switching device 10 of the first variant described above, the switching system according to the first variant has a movable contact arrangement 100. In addition, the switching system according to the first variant has the second movable contact arrangement 100'. For a description of the first and second movable contact arrangement 100 and 100', reference is made to the above description. In particular, as shown for example in Fig. 17, the switching system comprises a second transmission unit arranged between the drive unit and the movable second contact arrangement to move the second movable contact arrangement between the open position and the closed position. Like the first movable contact arrangement, the second movable contact arrangement has a second plurality of contact points for contacting the mating contact arrangement, wherein the second plurality of contact points reduces a current density in each of the contact points of the second plurality of contact points. Further, like the first transmission unit, the second transmission unit has a lever mechanism, wherein the lever mechanism of the second transmission unit increases the clamping force for each of the plurality of second contact points in the closed position.

[0097] In the solutions in Figures 15 to 17, the switching system according to the first variant further comprises a second drive unit with a second motor and preferably a second reduction transmission, wherein the second drive unit generates a clamping force to press the second movable contact arrangement against the mating contact arrangement in the closed position.

[0098] Alternatively, the switching device according to the second variant switches between a first position and a second position. In particular, movable contact arrangement 1100 moves a plurality of contact bridges in the same direction and the plurality of contact bridges are spaced apart in the direction of movement. This facilitates, as shown in Figs. 26 and 27, that at least one of the terminals can be arranged between the at least two contact bridges. This facilitates that the terminal can be contacted in the first position with one of the bridges at a first side and the same at least one terminal can be contacted in the second position with another one of the bridges at a second side.

[0099] Compared to the switching system according to the first variant the number of bus bars is reduced from five to four terminals and the number of bridges is reduced from four to three. Further, the need of bending the bus bars is overcome by arranging at least one of the terminals between two moving contact bridges, i.e. providing at least one of the terminals to having two opposing contact areas 1214_1 and 1214_2. Further, the number of contact plates is reduced from eight to six and the number of motors is reduced from two to one. Finally, the resistance in the serial path is only half compared to system of the first variant. The resistance is lower compared to using three discrete contactors.

[0100] Even if not explicitly discussed so far, the drive unit 300 can have a limiting device to stop the rotor. In particular, the limiting device may comprise a position element for limiting the movement of the transmission unit. For example, this may be formed by the reduction transmission guide 24. Additionally or alternatively, the limiting device may be formed by the circuit of the circuit board 350 by reducing the supply power of the motor, for example based on a power consumed by the motor. Additionally or alternatively, the guide element 442 or the slider 1120_2 or the corresponding linear guide may include a limiting device to stop the movement of the guide element 442 or the slider. For example, the limiting device may be provided at and / or formed by the end of the screw spindles 443_1, 443_2.

[0101] It should be understood that with reference to the figures, a lever mechanism with four articulated rods is shown. Alternatively, only a single articulated rod can be provided or a lever mechanism with a rotatably mounted lever can transmit a lever force.

[0102] It should be understood that, with reference to the figures, a movable contact arrangement with four contact areas has been shown. Alternatively, a movable contact arrangement with only a single contact area with a plurality of contact points can also realize a switching device.List of reference symbols:

[0103] Reference number Description 10, 10'Switching device22Bottom housing portion24Reduction transmission guide30Cover housing portion100Movable contact arrangement110, 110_1, 110_2Contact bridges120_1a, 120_1b, 120_2a, 120_2bContact fields130Contact plate132_1, 132_2Spring elements134_1, 134_2End stops200Mating contact arrangement210_a, 210_bClamping contact element220_1a, 220_2a, 220_1b, 220_2bMating contact areas230_a, 230_bTerminal232_a, 232_b, 232_c, 232_dTerminal240Contact element guide element250Connecting conductor300Drive unit310Motor320Drive shaft330Reduction transmission332, 334Gear wheel340Output shaft350Circuit board400, 1400Transmission unit410, 410_1 - 410_4articulated rod420, 420_1 - 420_4Drive unit joint430, 430_1 - 430_4Contact arrangement joint440Linear guide442Guide element443_1, 443_2Screw spindle444_1, 444_2SliderAAxial directionrRadial direction1110_1 - 1110_3contact bridges1120contact bridge holder1122Cam follower1212, 1214, 1222, 1224contact terminals1410Cam shaft1420Cam1430Driving wheel

Claims

1. A bistable switching device (10, 10') for switching an electric circuit between a first position, in which a movable contact arrangement (100, 1100) and a mating contact arrangement (200, 1200) are in a first stable state, and a second position, in which the movable contact arrangement (100, 1100) and the mating contact arrangement (200, 1212, 1214, 1222, 1224) are in a second stable state, the switching device (10) comprising: a drive unit (300) with a motor (310), wherein the drive unit (300) generates a contact normal force in order to press the movable contact arrangement (100, 1100) against the mating contact arrangement (200, 1212, 1214, 1222, 1224) in at least one of the first position and the second position; a transmission unit (400, 1400) arranged between the drive unit (300) and the movable contact arrangement (100, 1100) for moving the movable contact arrangement (100, 1100) between the first position and the second position; wherein the movable contact arrangement (100, 1100) comprises a plurality of contact points (132_1, 132_2), the plurality of contact points (132_1, 132_2) reducing a current density in each of the contact points (132_1, 132_2); and the transmission unit (400) further comprising a mechanical linkage mechanism (410, 420, 430, 1410, 1420, 1430), wherein the mechanical linkage mechanism (410, 420, 430, 1410, 1420, 1430) increases the contact normal force for the sum of the contact points of the plurality of contact points (132_1, 132_2) in at least one of the first position and the second position.

2. The switching device (10') according to claim 1, wherein the stable contact arrangement comprises a first pair of contact terminals (1212, 1222) of a first power-and-load-element and a second pair of contact terminals (1214, 1224) of a second power-and-load-element, wherein, the mechanical linkage mechanism (1410, 1420, 1430) connects the two power-and-load-elements in parallel in the first position and connects the two power-and-load-elements in series in the second position.

3. The switching device (10') according to any one of the preceding claims, wherein the stable contact arrangement comprises a plurality of terminals (1212, 1214, 1222, 1224), wherein at least one of the terminals (1212, 1214, 1222, 1224) comprises a first contact area (1214_1) for contacting the movable contact arrangement in the first position and the at least one terminal (1214) comprises a second contact area (1214_1) opposing the first contact area (1214_2) for contacting the movable contact arrangement in the second position.

4. The switching device (10, 10') according any one of the preceding claims, wherein the motor (310), in particular a DC motor, has a rotor for driving a drive shaft (320) extending in an axial direction (A), and the drive unit (300) comprises a reduction transmission (330) and an output shaft (340) extending in the axial direction (A), wherein the output shaft (340) is driven by the reduction transmission (330), the output shaft (340) and the rotor of the motor (310) being arranged next to one another, optionally, wherein the drive unit (300) has a limiting device to stop the rotor, in particular wherein the limiting device comprises a position element for limiting the movement of the transmission unit and / or wherein the limiting device reduces the supply power of the motor (310) based on a power absorbed by the motor (310).

5. The switching device (10, 10') according to any one of the preceding claims, wherein the drive unit (300) comprises a reduction transmission (330) with a gear transmission (332, 334), wherein the gear transmission (332, 334) is arranged between a drive shaft (320) of the motor (310) and an output shaft (340) of the drive unit (300).

6. The switching device (10') according to any one of the preceding claims, wherein the mechanical linkage mechanism (1410, 1420, 1430) comprises: a cam mechanism comprising a cam shaft (1410) for being rotated by an output shaft (340) of the drive unit (300) and a cam (1420) for converting the rotational movement of the cam shaft (1410) for reciprocating movement of the movable contact arrangement between the first position and the second position.

7. The switching device (10') according to claim 6, wherein the cam mechanism comprises a driving wheel (1430) rotated by the drive unit (300) and wherein the driving wheel (1430) and the cam (1420) form a reduction transmission for increasing the contact normal force, optionally the cam mechanism further comprising a gear transmission, wherein the gear transmission is arranged between the output shaft (340) of the drive unit (300) and the drive wheel (1430) of the cam mechanism.

8. The switching device (10') according to any one of the preceding claims, wherein the mechanical linkage mechanism (1410, 1420, 1430) further comprises: a contact bridge holder (1120) for moving at least one contact bridge (1110_1, 1110_2, 1110_3) between the first position and the second position.

9. The switching device (10') according to claims 6 or 7 and claim 8, wherein the contact bridge holder (1120) comprises at least one cam follower (1122) for following the reciprocate movement of the at least one cam (1420).

10. The switching device (10') according to any one of claims 8 to 9, wherein the switching device comprises a linear guide for guiding a slider (1120_2) of the contact bridge holder (1120).

11. The switching device (10') according to any one of the preceding claims, wherein the mechanical linkage mechanism comprises: at least one first contact bridge (1110_2, 1110_3) for parallel connection of two power-and-load-elements in the first position; and a second contact bridge (1110_1) for serial connection of the two power-and-load elements in the second position.

12. The switching device (10') according to any of claims 8 to 10 and claim 11, wherein the first contact bridge (1110_1, 1110_2) and the second contact bridge (1110_3) are hold by the contact bridge holder (1120).

13. The switching device (10') according to any of claims 11 to 12, wherein at least one contact bridge (1110_1, 1110_2, 1110_3) is formed from a one-side coated metal bar.

14. The switching device (10, 10') according to any one of the preceding claims, further comprising a contact plate (130), wherein each of the contact points of the plurality of contact points (132) is formed by a spring element (132) of the contact plate (130), in particular wherein the contact plate (130) comprises at least one end stop (134) to prevent overstretching of the spring element (132).

15. The switching device (10') according to any one of claims 2 and 3 and claim 14, wherein at least one of the terminals (1110) comprises the contact plate (130).

Images