Disc cam gearing for compensating for the compression force in vacuum interrupters

Abstract

The present invention relates to circuit breakers for selectively providing an electrically conductive connection, in particular circuit breakers having vacuum interrupters, wherein preferably non-linear load profiles at components of a kinematic chain are prevented. A circuit breaker (10) for selectively providing an electrically conductive connection is accordingly proposed, comprising at least one interrupter unit (12) which comprises an enclosure (14) with a movable contact element (16) arranged therein, wherein each movable contact element (16) is prestressed by a prestress element which is arranged on an end region of the enclosure (14) which is opposite the contact surface of the contact element, a switch housing (21), wherein the at least one interrupter unit (12) is housed in the switch housing (21) and each prestress element is subject to the pressure in the switch housing (21), and an actuator which is arranged outside of the switch housing (21) and is set up to selectively activate the respective movable contact element (16). According to the invention, the circuit breaker (10) further comprises a limiting element, preferably outside of the switch housing (21), which is set up to limit a movement of the respective movable contact element (16), wherein the respective movable contact element (16) and the actuator are coupled in terms of force and / or coupled in terms of torque via the limiting element.

Description

[0001] Description

[0002] Cam disc gear for compensating the pressure force in vacuum interrupters

[0003] The present invention relates to circuit breakers for selectively providing an electrically conductive connection, in particular circuit breakers with vacuum interrupters, wherein non-linear load profiles on components of a kinematic chain are preferably avoided.

[0004] Circuit breakers are used in medium-voltage and high-voltage systems, for example with voltages up to around 40 kV or up to around 150 kV or even up to around 1200 kV for power generation and transmission, to enable network separation in the event of deviations from normal operating currents, for example in the event of continuous overload currents and / or high short-circuit currents. In this way, systems can be protected from damage even when such high currents occur. To enable switching or separation, the circuit breakers contain one or more interrupter units which can interrupt an electrically conductive connection when switched accordingly. This usually involves separating a movable contact element from a fixed contact element so that the corresponding contact surfaces no longer touch and are spaced apart from one another.

[0005] In order to prevent a developing arc from posing a danger to the immediate vicinity in the event of such an interruption, non-flammable gases were previously introduced into the interrupter unit to bind free electrons and prevent the spread of flammable, ionic gases. A frequently used gas for such applications is sulphur hexafluoride (SF6). However, because sulphur hexafluoride acts as a strong greenhouse gas in the atmosphere, solutions were sought that enable climate-neutral implementation of switching devices and switchgear. One such climate-neutral solution is the use of vacuum interrupters, where a vacuum is provided in the interrupter unit instead of an insulation medium, so that even in the event of an arc occurring, no spreading ionization occurs.Due to the pressure difference between the vacuum interrupter and the surrounding switch housing, an approximately constant pressure force acts in the direction of the ON position from the OFF position of the circuit breaker until the galvanic contact of the contact surfaces of the contact elements.

[0006] It has been shown that the compressive force exerted on the bellows located in the vacuum tube has a significant influence on the kinematic chain used to switch the circuit breaker. To at least partially reduce this adverse effect, a second bellows was previously provided between the breaker housing and the surrounding area. The relevant diameter can be dimensioned such that the forces from the breaker bellows to the bellows almost cancel each other out.

[0007] One problem, however, is that the switch and tubular bellows do not both act throughout the entire switching movement. This is because while the compressive force on the switch bellows acts throughout the entire switching movement, the compressive force on the tubular bellows only acts on the kinematic chain between the OFF position and the position of the first galvanic contact, so that at the end of the closing movement only the switch bellows acts on the kinematic chain. The resulting force is opposite to the direction of movement of the closing movement, meaning that the switch drive must counteract this additional force during closing. This can, for example, require greater closing spring energies.

[0008] Furthermore, the bellows can cause a non-linear load distribution on components of a kinematic chain, for example, with different kinematic chains, especially with different transmission ratios, such as on reversing levers. The switch bellows cannot adequately compensate for such non-linear loads.

[0009] Description of the invention

[0010] According to the invention, it was recognized that current switch bellows-based solutions can provide a certain compensation force in the area between an OFF position and a first galvanic contact in a circuit breaker. This compensation force for the compressive force acting on the bellows can be selected depending on the dimensioning of the switch bellows or the switch bellows force. However, in order to provide an almost complete compensation force, the force counteracting the closing action is the greatest. Conversely, a closing force can be reduced, for example, if the switch bellows is smaller. However, with such a design, no sufficient compensation effect could be determined.

[0011] Based on the known prior art, it is therefore an object of the present invention to provide an improved circuit breaker. In particular, one object can be seen in providing improved compensation for a force emanating from an interrupter unit, which does not cause additional stress on a kinematic chain of the circuit breaker.

[0012] The problem is solved by a circuit breaker having the features of claim 1. Advantageous further developments emerge from the subclaims, the description, and the figures.

[0013] Accordingly, a circuit breaker for selectively providing an electrically conductive connection is proposed, comprising at least one interrupter unit which comprises a casing with a movable contact element arranged therein, wherein each movable contact element is prestressed by a biasing element which is arranged at an end region of the casing opposite the contact surface of the contact element. The circuit breaker further comprises a switch housing, wherein the at least one interrupter unit is accommodated in the switch housing and each biasing element is exposed to the pressure in the switch housing, and an actuator which is arranged outside the switch housing and is configured to selectively actuate the respective movable contact element.According to the invention, the circuit breaker further comprises a limiting element which is designed to limit a movement of the respective movable contact element, wherein the respective movable contact element and the actuator are force-coupled and / or torque-coupled via the limiting element.

[0014] The limiting element makes it possible to compensate for a force acting on the respective pre-tensioning element, thus preventing any undesired movement of the corresponding movable contact element toward an ON position or a galvanic contact of the circuit breaker. In other words, the limiting element ensures that the respective movable contact element can be securely held in its position, particularly in the OFF position.

[0015] The pressure in the switch housing is preferably greater than in the casing of the respective interrupter unit. This positive pressure difference emanating from the interior of the switch housing allows the respective prestressing element to extend or expand, whereby a contact surface of the movable contact element can be moved toward a contact surface of a contact element that is also fixedly arranged in the interrupter unit. However, such movement is effectively prevented by the limiting element.

[0016] Furthermore, due to the force coupling and / or torque coupling provided by the limiting element, it is possible for the force acting on the actuator to be reduced to essentially zero. This is because the compressive force acting on the respective preload element is more or less balanced or compensated for by the limiting element, so that neither additional loading nor force adjustment of the actuator is necessary. The force coupling or, in particular, the torque coupling also enables non-linear compensation, whereby a force acting on the limiting element from the movable contact element, in the event of a non-linear increase, is more or less automatically compensated by a corresponding increase in a counteracting force or counteracting torque provided by the limiting element.

[0017] The limiting element can be arranged in the switch housing, for example, to enable a particularly compact arrangement. Preferably, the limiting element is arranged outside the switch housing. In this way, the limiting element can be provided, for example, for retrofitting and / or more easily integrated or implemented in a component of the actuator. Furthermore, such an arrangement can significantly facilitate any subsequent adaptation of the limiting element.

[0018] Preferably, the respective prestressing element is designed in the shape of a tubular bellows and / or the switch housing is free of a switch bellows. A tubular bellows can, for example, be provided at an end region of the shell and provide a connection between the shell and the movable contact element, the tubular bellows shape enabling bilateral movement of the contact element, i.e. both in the direction of the fixed contact element and also a movement whereby the corresponding contact surfaces are separated from one another. The tubular bellows shape can, for example, typically be provided in an interrupter unit and in this way provide a certain stability for the movable contact element. The compressive force acting on the prestressing element can thus bring about prestressing in the direction of the ON position. However, according to the invention this is effectively prevented by the limiting element.

[0019] The limiting element can indeed be provided in addition to a switch bellows, for example to facilitate retrofitting or to at least partially compensate for an occurring linear force using the switch bellows. The function of such a switch bellows acting outwards or towards the environment is preferably replaced by the limiting element, so that a force acting on the movable contact element from the pressure inside the switch housing is preferably counteracted exclusively by the limiting element. This means that no additional components are required and the complexity of the circuit breaker can be reduced. For example, sealing the interior of the switch housing from the environment can be simplified. Furthermore, the compensating force or the compensating torque provided by the limiting element can be directly adapted to the force emanating from the respective pretensioning element.

[0020] Preferably, the respective interrupter unit is designed as a vacuum interrupter and / or the pressure in the switch housing is greater than ambient pressure, in particular greater than 1 bar. The design as a vacuum interrupter has the advantage that an insulating medium in the enclosure is unnecessary, while still effectively preventing the spread of any arc that may occur in the interrupter unit. In this respect, an overpressure in the switch housing can provide advantageous dielectric insulation.

[0021] In a configuration as a vacuum interrupter, the interior of the enclosure is preferably fluidically sealed from the interior of the switch housing via the respective prestressing element. The respective movable contact element is preferably firmly connected to a longitudinal end of the prestressing element and thus fluidically sealed. Thus, the movable contact element can be connected to a longitudinal end region of a bellows arranged inside the enclosure, wherein an opposite end region of the bellows is arranged at the corresponding end region of the enclosure and provides a fluid seal between the enclosure and the interior of the switch housing.

[0022] In order to provide an improved compensation force and in particular an improved non-linear compensation force, the limiting element can advantageously be designed as a cam mechanism, wherein a cam member of the cam mechanism is connected to the movable contact element and the actuator and coupled to an energy store.

[0023] Both the respective movable contact element and the actuator or actuating element or drive element can be connected to the cam element by means of a connection via a respective deflection lever. In this way, a drive force provided by the actuator for switching the circuit breaker can be passed on to the movable contact element via the cam mechanism. At the same time, however, the mechanical coupling with the energy store enables a force emanating from the pretensioning element and acting on the limiting element to be compensated. In other words, the energy store preferably exerts a counterpressure on the cam element in such a way that a torque generated by the pretensioning element on the cam element is canceled out by a torque provided by the energy store on the cam element.In this way, loads on the actuator can be avoided as far as possible, both in the switched or disconnected state and during a movement of the movable contact element in the direction of the fixed contact element, without this requiring an adjustment of the switching force.

[0024] Although the energy storage device can be mechanically coupled directly to the cam member, it is preferably provided that the cam member is coupled to the energy storage device via an engagement member of the cam mechanism. The engagement member preferably comprises a lever, wherein the lever is coupled to the cam member by means of a roller arranged at its longitudinal end region and is coupled to the energy storage device at its opposite end region. The energy storage device is preferably a spring.

[0025] The roller at one end of the lever and the energy storage device at the other end allow for a more controlled impression on the cam element, providing improved coordination of the counterforce with the force emitted by the preload element. Furthermore, non-linear loads caused by the lever and the indirect coupling of the energy storage device to the cam element can be better accounted for and absorbed. The design of the energy storage device as a spring enables simplified implementation and fine adjustment of the spring force to be provided.

[0026] The cam member is preferably designed as a cam disk mounted on a shaft. The cam disk can be configured in particular such that a torque acting on the cam disk is predetermined by the contour of the cam disk in such a way that a movement of the cam disk causes a non-linear loading of the engagement member.

[0027] For example, the cam disc can have different radii in the circumferential direction and / or a discontinuous radial extent. Accordingly, the engagement member can be actuated differently upon corresponding contact with the cam disc, or an impression on the cam disc can be non-linear, for example due to a different leverage force provided by the energy storage device and deflection of the lever. The cam disc can be designed symmetrically with regard to its longitudinal axis, but can also be designed asymmetrically, for example to provide a predetermined torque for a certain position range of the movable contact element between an OFF position and the galvanic contact.

[0028] The shaft of the cam disc can also be formed as part of the actuator. In this way, the shaft can be provided, for example, as part of a kinematic chain for the limiting element, so that the limiting element can be easily integrated or implemented in a kinematic chain and the complexity of the circuit breaker can be reduced.

[0029] In order to support a torque coupling, the engagement member and / or the cam member can be designed for a rotational movement and / or a translational movement. The cam member and the engagement member can therefore preferably be arranged such that the cam member is designed for a rotational movement and the engagement member is designed for a translational movement relative to the cam member. Alternatively, it can also be provided that the cam member is also designed for a translational movement. For this purpose, for example, a slotted guide for the cam member can be provided, with the engagement element being mounted accordingly in order to absorb transverse forces occurring during guidance. Furthermore, it can be provided that both the engagement member and the cam member are designed for a rotational movement.In particular, a rotation can also cause a translational force or translation of the respective movable contact element, so that different loads occurring during a movement of the movable contact element can be compensated due to the torque coupling and the actuator is relieved accordingly.

[0030] Preferably, an instantaneous radius or a numerical curve of the cam element and / or a force range of the energy storage device are dimensioned to compensate for a force emanating from the respective prestressing element and acting on the limiting element in the non-electrically conductive state of the circuit breaker. Such compensation is preferably provided both in the OFF state of the circuit breaker and in every position between the OFF state and a position in which a galvanic contact is provided. In this way, the actuator or the drive of the circuit breaker can be completely relieved of the loads provided by the respective prestressing element, in particular a bellows.For example, an instantaneous radius can be larger at an outer angular range of the cam element, so that a counteracting torque provided by the limiting element is not increased linearly upon corresponding rotation of the cam element or cam disc. Furthermore, it can be provided that the instantaneous radius or the force range are also dimensioned to compensate for a force of a possibly present switch bellows on the switch housing, wherein the compensation is provided both in the electrically conductive and in the electrically non-conductive state.

[0031] To provide an advantageous drive for the circuit breaker, the actuator is preferably designed as a kinematic chain. The actuator can comprise a spring-loaded actuator. The kinematic chain can provide or facilitate switching of the circuit breaker, while still ensuring the required drive force and largely compensating for loads on the kinematic chain.

[0032] The circuit breaker can, for example, be designed as a single-break circuit breaker and comprise a single interrupter unit. The corresponding movable contact element can be mechanically coupled or connected to the limiting element by means of a connection, preferably outside the switch housing. Accordingly, the limiting element provides a torque or force that counteracts a torque or force on the limiting element provided by only one movable contact element or its prestressing element.

[0033] However, the circuit breaker can also be designed as a double-breaking circuit breaker and accordingly comprise two interrupter units, wherein the movable contact elements of the interrupter units are connected to the limiting element via a single connection. Accordingly, the limiting element provides a torque or a force which counteracts a torque or a force on the limiting element which is greater than that of a single-breaking circuit breaker. In the case of a double-breaking circuit breaker, the voltage to be controlled can be divided accordingly between two interrupter units, wherein the non-linear loads can be more pronounced due to the plurality of movable contact elements.To take this into account, a cam mechanism or a cam disk and an energy storage device can be dimensioned accordingly as part of an advantageous embodiment of the limiting element. Alternatively, it can also be provided that an individual limiting element is provided for each interrupter unit or each movable contact element.

[0034] Preferred further embodiments of the invention are explained in more detail by the following description of the figures. In the figures:

[0035] Figure 1 is a schematic representation of a single-break circuit breaker according to the prior art;

[0036] Figure 2 is a schematic representation of a double-breaking circuit breaker according to the prior art;

[0037] Figure 3 is a graphical representation of the forces acting on the switch bellows for various designs of a switch bellows according to the prior art; Figure 4 is a schematic representation of a circuit breaker according to the invention in a preferred embodiment;

[0038] Figure 5 is a schematic detailed view of the cam mechanism according to Figure 4; and

[0039] Figure 6 is a graphical representation of the torques on the cam mechanism according to Figure 4.

[0040] Detailed description of preferred embodiments

[0041] Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements in the various figures are provided with identical reference symbols, and a repeated description of these elements is partially omitted to avoid redundancies.

[0042] Figure 1 schematically illustrates a prior art single-break circuit breaker 10. It can be seen that the circuit breaker 10 comprises a single interrupter unit 12 having a casing 14 in which a movable contact element 16 is at least partially accommodated. The movable contact element 16 can be switched accordingly to provide an electrically conductive connection to a fixed contact element 18 or to be separated therefrom in the event of sustained overvoltages.

[0043] The interrupter unit 12 is arranged in the housing interior 22 of a switch housing 21, wherein the interrupter unit 12 is designed in this case as a vacuum interrupter or vacuum tube. Accordingly, a pressure of 0 (zero) bar is present within the casing 14. In contrast, in the housing interior 22 of the switch housing 21, there is a pressure which is greater than the ambient pressure and preferably greater than 1 bar, in particular between 5 bar and 10 bar or higher than 10 bar. In this way, a switching arc which may arise when the movable contact element 16 is separated from the fixed contact element 18 can be virtually shielded due to the vacuum or the switching arc can be prevented from extending beyond the interrupter unit 12.

[0044] The movable contact element 16 is connected to the casing 14 via a pretensioning unit, which in this case is designed as a bellows 20. In this way, the movable contact element 16 can be held securely, while still allowing movement in the event of a corresponding switching of the circuit breaker 10. However, due to the higher pressure in the housing interior 22 compared to the vacuum within the casing 14, there is a compressive force on the bellows 20, as indicated by the corresponding arrows. Accordingly, the movable contact element 16 can move in the direction of the fixed contact element 18 even in an OFF position and without a corresponding switching of the circuit breaker 10.

[0045] To prevent this, a switch bellows 23 is provided on the switch housing 21, which is also connected to the movable contact element 16. The switch bellows 23 is dimensioned such that a counterforce is provided which is directed opposite to the force acting on the tubular bellows 20 and thus prevents or at least reduces unintentional movement of the movable contact element 16. The switch bellows 23 is indirectly connected to a spring-loaded drive 24 via a reversing lever 25, which is part of a kinematic chain 26.

[0046] A corresponding design of a double-break circuit breaker according to the prior art is shown schematically in Figure 2. Accordingly, two interrupter units 12 are provided in the housing interior 22 of the switch housing 21, with the respective movable contact elements being connected to the switch bellows 23 via a connection. With a double-break circuit breaker, the voltage to be controlled can be divided accordingly between two interrupter units. With appropriate switching by means of the spring-loaded drive 24, the current can be switched or interrupted.

[0047] A disadvantage of using a switch bellows 23 is that a sufficient counterforce or switch bellows force must be provided for a reduced movement of the movable contact element(s). However, this switch bellows force must be taken into account when designing the spring-loaded drive 24 or the kinematic chain 26. Furthermore, the switch bellows 23 only allows linear compensation, so that non-linear loads cannot be adequately compensated or oversizing of the switch bellows 23 is necessary. This relationship is shown graphically in Figure 3 for various designs of the switch bellows 23.

[0048] Accordingly, it can be seen that the various compensation forces B1-B3 of the switch bellows 23 achieve a reduction in the resulting force at the outer end of the switch bellows 23 facing the environment compared to an uncompensated force A, whereby with the greatest compensation force B3 it can be achieved that the effect of the tubular bellows in the position range between the OFF position and the galvanic contact (GAL) is almost completely compensated. However, this means that for switching on (ON) a larger switch bellows force C3 has to be provided in order to enable switching on. The corresponding switch bellows force C1, C2 is lower for the compensated forces B1 and B2. However, with these compensated forces B1 and B2 the compensation effect is also considerably lower.

[0049] According to the invention, a circuit breaker 10 was developed which solves the above problems. A preferred embodiment is shown schematically in Figure 4.

[0050] The circuit breaker 10 is designed as a two-circuit

[0051] Circuit breaker 10 is formed, wherein the switch housing 21 and the components arranged therein substantially correspond to the design according to Figure 2. In contrast to Figure 2, however, in the illustrated, preferred embodiment the switch housing 21 does not comprise a switch bellows 23, but rather a limiting element in the form of a cam gear 27 is provided, as indicated by the dashed area. Accordingly, the movable contact elements 16 are connected to the cam gear 27 by means of a connection and the cam gear 27 is connected at its opposite end to a spring-loaded drive 24 by means of a corresponding connection.

[0052] In this case, a torque coupling is provided by the cam mechanism 27, wherein a torque caused by the movable contact element 16 or the tubular bellows on the cam mechanism is canceled out or compensated for by a counteracting torque provided by the cam mechanism 27. This is indicated by the corresponding arrows. In this way, unfavorable preload forces on the respective interrupter units 12 can be advantageously compensated for. At the same time, unfavorable loads on the actuator or the spring-loaded drive 24 are avoided. The torque compensation also makes it possible to provide compensation during a movement or when switching the circuit breaker, wherein the design also means that non-linear loads can be (almost) completely compensated for.

[0053] This is because the cam mechanism 27, as shown in more detail in Figure 5, can advantageously have a cam disk which is mounted on a shaft 30. The contour of the cam disk 28 is not continuous. In other words, the radius of the cam disk 28 is not continuous in the circumferential direction. When coupled to an engagement member 32, a non-linear counterforce can therefore advantageously be provided. In the present example, the engagement member 32 is designed as a lever 34, which has a roller 36 on one longitudinal end region which engages with the cam member or the cam disk 28. At the opposite end region of the lever 34, the lever 34 is coupled to an energy store, which in this case is designed as a spring 38.With a corresponding change in the torque and a concomitant rotation of the cam disc 28, a corresponding counterforce is exerted on the cam disc 28 by the spring 38 due to the contour of the cam disc 28 and the engagement of the roller 36, which counterforce provides a counteracting torque and enables effective torque compensation.

[0054] Such torque compensation is shown graphically in Figure 6. It can be seen that a torque of the bellows D provided at the cam gear 27 does not run linearly with a corresponding rotation at the deflection gear and during a movement from the OFF position in the direction of the galvanic contact (GAL). At the same time, however, a torque E emanating from the cam gear 27 is provided at the cam gear 27 due to the impression of the roller 36 on the cam disk 28 and the coupling with the spring 38 via the lever 34. The resulting torque is a compensated torque F, which advantageously enables sufficient compensation for almost the entire angle of the deflection gear or for almost the entire path from the OFF position in the direction of the galvanic contact.Accordingly, loads which are caused by the tubular bellows according to the state of the art, and in particular non-linear loads on a kinematic chain, can be completely prevented without this requiring an adjustment of the kinematic chain and / or the spring-loaded drive.

[0055] Where applicable, all individual features shown in the embodiments may be combined and / or interchanged without departing from the scope of the invention. List of reference symbols

[0056] 10 circuit breakers

[0057] 12 Breaker unit

[0058] 14 Cover

[0059] 16 Movable contact element

[0060] 18 Fixed contact element

[0061] 20 bellows

[0062] 21 switch housing

[0063] 22 Housing interior

[0064] 23 Switch bellows

[0065] 24 spring-loaded drive

[0066] 25 bell cranks

[0067] 26 Kinematic chain

[0068] 27 cam gears

[0069] 28 cam disc

[0070] 30 wave

[0071] 32 intervention member

[0072] 34 levers

[0073] 36 roll

[0074] 38 spring

[0075] A Uncompensated force

[0076] B1-B3 Compensated force

[0077] C1-C3 Switch bellows force D Torque bellows

[0078] E torque cam gear

[0079] F Compensated torque

Claims

Patent claims 1. A circuit breaker (10) for selectively providing an electrically conductive connection, comprising at least one interrupter unit (12) comprising a casing (14) with a movable contact element (16) arranged therein, each movable contact element (16) being prestressed by a biasing element arranged at an end region of the casing (14) opposite the contact surface of the contact element, a switch housing (21), the at least one interrupter unit (12) being accommodated in the switch housing (21) and each biasing element being subjected to the pressure in the switch housing (21), and an actuator arranged outside the switch housing (21) and configured to selectively actuate the respective movable contact element (16), characterized by a limiting element configured to limit a movement of the respective movable contact element (16),wherein the respective movable contact element (16) and the actuator are force-coupled and / or torque-coupled via the limiting element., 2. Circuit breaker (10) according to claim 1, wherein the limiting element is arranged outside the switch housing (21).

3. Circuit breaker (10) according to claim 1 or 2, wherein the respective prestressing element is designed in the shape of a tubular bellows (20) and / or wherein the switch housing (21) is free of a switch bellows (23).

4. Circuit breaker (10) according to one of the preceding claims, wherein the respective interrupter unit (12) is designed as a vacuum interrupter and / or wherein the pressure in the switch housing (21) is greater than an ambient pressure, in particular greater than 1 bar.

5. Circuit breaker (10) according to one of the preceding claims, wherein the limiting element is designed as a cam mechanism (27), wherein a cam member of the cam mechanism (27) is connected to the movable contact element (16) and the actuator and coupled to an energy store.

6. Circuit breaker (10) according to claim 5, wherein the cam member is coupled to the energy storage device via an engagement member (32) of the cam mechanism (27).

7. Circuit breaker (10) according to claim 6, wherein the engagement member (32) comprises a lever (34), wherein the lever (34) is coupled to the cam member by means of a roller (36) arranged at its longitudinal end region and is coupled to the energy store at its opposite end region, preferably with a spring (38).

8. Circuit breaker (10) according to claim 6 or 7, wherein the cam member is designed as a cam disc (28) which is mounted by a shaft (30).

9. Circuit breaker (10) according to claim 8, wherein a torque acting on the cam disc (28) is predetermined by the contour of the cam disc (28) such that a movement of the cam disc (28) causes a non-linear loading of the engagement member (32).

10. Circuit breaker (10) according to claim 8 or 9, wherein the shaft (30) is formed as part of the actuator.

11. Circuit breaker (10) according to one of claims 5 to 10, wherein the engagement member (32) and / or the short-circuit venglied are designed for a rotational movement and / or a translational movement.

12. Circuit breaker (10) according to claim 11, wherein the engagement member (32) is designed for a translational movement relative to the cam member and wherein the cam member is designed for a rotational movement, or wherein the cam member is designed for a translational movement and comprises a slotted guide, wherein the engagement element is mounted to absorb transverse forces.

13. Circuit breaker (10) according to one of claims 5 to 12, wherein an instantaneous radius of the cam member and / or a force range of the energy storage device are dimensioned to compensate for a force emanating from the respective prestressing element and acting on the limiting element in the non-electrically conductive state of the circuit breaker (10).

14. Circuit breaker (10) according to one of the preceding claims, wherein the actuator is designed as a kinematic chain (26).

15. Circuit breaker (10) according to claim 14, wherein the actuator comprises a spring-loaded actuator (24).

16. Circuit breaker (10) according to one of the preceding claims, which is designed as a single-break circuit breaker (10) and comprises a single interrupter unit (12).

17. Circuit breaker (10) according to one of claims 1 to 15, which is designed as a double-break circuit breaker (10) and comprises two interrupter units (12), wherein the movable contact elements (16) of the interrupter units (12) are connected via a single connection connection are connected to the limiting element or wherein each breaker unit is connected to an individual limiting element.

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