ELECTRIC SWITCHING DEVICE WITH IMPROVED ACTUATION MECHANISM

Some embodiments relate to an electric switching device, which comprises a switching contact, an actuation mechanism coupled to the switching contact and a motor coupled to the actuation mechanism. The actuation mechanism comprises a first spring, a first actuation plate coupled with the switching contact and a second actuation plate coupled with the motor. The actuation mechanism also comprises a first blocking element, which blocks the first actuation plate in a rotational blocking position and releases the first actuation plate in a rotational release position. The first spring is loaded by a movement of the motor. At some point in time, the second actuation plate or an actuating element connected thereto turns the first blocking element and thus releases the first actuation plate. As a consequence, the first actuation plate starts to move and finally actuates the switching contact.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure claims the priority to Great Britain patent application with the filing number 2303834.2 filed on Mar. 16, 2023 with the UK Intellectual Property Office, the contents of which are incorporated herein by reference in entirety.

TECHNICAL FIELD

The presently disclosed subject matter relates to an electric switching device, which comprises a switching contact (or more switching contacts), an actuation mechanism coupled to the switching contact and a motor coupled to the actuation mechanism.

BACKGROUND ART

An electric switching device of the above kind is generally known in prior art. To move the movable contact of a switching device, an actuation mechanism coupled with a motor can be used. To prevent or at least reduce arcing in case of switching (on or off), the movable contact shall move with a sufficient speed. However, that requires high drive powers and without special measures a high power motor. To obviate the need for high power motors, a motor in such an application is often coupled with an actuation mechanism, which converts a comparably slow movement of the motor into a high speed movement of the switching contact. Often, springs are used for this reason, which are loaded by the motor and at a particular point in time release and more or less instantaneously move the movable contact of the switch. In other words, energy loaded into the springs is released within a short time what means high mechanical power. A number of actuation mechanisms have been proposed, which however often are bulky.

DETAILED DESCRIPTION

Accordingly, the aspect of the presently disclosed subject matter is the provision of an improved electric switching device, and in particular the provision of an improved actuation mechanism. In particular, a slim actuation mechanism for an electric switching device shall be provided. More particularly, such an actuation mechanism shall be suitable for retrofitting of manually operated switching contacts.

The aspect of the presently disclosed subject matter is solved by an electric switching device of the type disclosed in the opening paragraph, which comprisesa first spring,a first actuation plate connected to or contacting the first spring and coupled with the switching contact,a second actuation plate connected to or contacting the first spring and coupled with the motor, wherein the second actuation plate is spaced from the first actuation plate with at least a part of the first spring in-between, anda first blocking element, which comprises a rotatable first flattened shaft (also called as “D-shaft”) and a first lever connected to the first flattened shaft and which is designed to block the first actuation plate in a rotational blocking position and to release the first actuation plate in a rotational release position,wherein the second actuation plate is movable in a first direction by the motor,wherein the first spring or said part thereof upon movement of the second actuation plate in the first direction is loaded,wherein the second actuation plate or an actuating element connected thereto upon further movement of the second actuation plate in the first direction contacts the first lever,wherein the second actuation plate or the actuating element upon further movement of the second actuation plate in the first direction turns the rotatable first flattened shaft from its rotational blocking position in its rotational release position andwherein the first flattened shaft upon reaching its release position releases the first actuation plate, which in turn is moved in the first direction by a release of the loaded first spring or said loaded part of the first spring and as a consequence transfers the switching contact into a first switching state (e.g. into the open state).

A first actuation plate coupled with the switch is held in position by a first blocking element. To initiate a switching operation, the motor moves a second actuation plate thereby loading (e.g. by compressing or tensioning) a first spring arranged between the two actuation plates. At some point in time, the second actuation plate or an actuating element connected thereto turns the first blocking element from a blocking position into a release position and thus releases the first actuation plate. In turn, the first actuation plate forcefully accelerates into a first direction driven by the first spring and as a consequence quickly changes the switching state of the switching contact.

By use of the above measures, a slim, durable and reliably actuation mechanism is presented, which provides a good conversion of a movement of a slow moving motor into a high speed movement of a movable switching contact. Accordingly, arcing can be prevented or at least reduced in case of switch on or switch off without having the need of high power motors. For example, such electric switching devices can be used for low voltage, medium voltage and high voltage, in particular in combination with vacuum interrupters, and can also be embodied as (hard-) gas based switching devices. The coupling between the actuation mechanism and the switching contact or between the actuation mechanism and the motor may comprise but is not limited to linearly movable rods and rotatable levers and other rotating elements.

Further advantageous embodiments are disclosed in the claims and in the description as well as in the figures.

Advantageously, the electric switching device comprises a second blocking element, which comprises a rotatable second flattened shaft and a second lever connected to the second flattened shaft and which is designed to block the first actuation plate in a rotational blocking position and to release the first actuation plate in a rotational release position,wherein the second actuation plate is movable in a second direction opposite to the first direction by the motor,wherein the first spring upon movement of the second actuation plate in the second direction is loaded,wherein the second actuation plate or an actuating element connected thereto upon further movement of the second actuation plate in the second direction contacts the second lever,wherein the second actuation plate or the actuating element upon further movement of the second actuation plate in the second direction turns the rotatable second flattened shaft from its blocking position in its release position andwherein the second flattened shaft upon reaching its release position releases the first actuation plate which in turn is moved in the second direction by a release of the loaded first spring and as a consequence transfers the switching contact into a second switching state (e.g. into a closed state).

In this embodiment, a second blocking element hinders a movement of the first actuation plate in a second direction opposite to the first direction. At some point in time, the second actuation plate or an actuating element connected thereto turns the second blocking element from a blocking position into a release position and thus releases the first actuation plate. In turn, the first actuation plate forcefully accelerates into the second direction driven by the first spring and as a consequence quickly changes the switching state of the switching contact. The second blocking element may provide more design freedom when designing the actuation mechanism.

In yet another advantageous embodiment, the electric switching device comprisesa second spring,a third actuation plate connected to or contacting the second spring and coupled with the motor, wherein the third actuation plate is spaced from the first actuation plate with the second spring in-between, andwherein the third actuation plate is movable in a second direction opposite to the first direction by the motor,wherein the second spring upon movement of the third actuation plate in the second direction is loaded and

Wherein in a Case a)

the third actuation plate or an actuating element connected thereto upon further movement of the third actuation plate in the second direction contacts the first lever,the third actuation plate or the actuating element upon further movement of the third actuation plate in the second direction turns the rotatable first flattened shaft from its blocking position in its release position andthe first flattened shaft upon reaching its release position releases the first actuation plate which in turn is moved in the second direction by a release of the loaded second spring and as a consequence transfers the switching contact into a second switching state (e.g. closed state) or

Wherein in a Case b)

the electric switching device comprises a second blocking element, which comprises a rotatable second flattened shaft and a second lever connected to the second flattened shaft and which is designed to block the first actuation plate in a rotational blocking position and to release the first actuation plate in a rotational release position,the third actuation plate or an actuating element connected thereto upon further movement of the third actuation plate in the second direction contacts the second lever,the third actuation plate or the actuating element upon further movement of the third actuation plate in the second direction turns the rotatable second flattened shaft from its blocking position in its release position andthe second flattened shaft upon reaching its release position releases the first actuation plate which in turn is moved in the second direction by a release of the loaded second spring and as a consequence transfers the switching contact into a second switching state (e.g. closed state).

In this embodiment, two springs and two actuation plates coupled with the motor are used for the actuation mechanism. In case a) there is just one blocking element, whereas in case b) there are two blocking elements.

In yet further advantageous embodiment, the electric switching device comprisesa second spring,a third actuation plate connected to or contacting the second spring and coupled with the motor,a fourth actuation plate connected to or contacting the second spring and coupled with the switching contact, wherein the third actuation plate is spaced from the fourth actuation plate with the second spring in-between, andwherein the third actuation plate is movable in a second direction opposite to the first direction by the motor,wherein the second spring upon movement of the third actuation plate in the second direction is loaded,

Wherein in a Case a)

the third actuation plate or an actuating element connected thereto upon further movement of the third actuation plate in the second direction contacts the first lever,the third actuation plate or the actuating element upon further movement of the third actuation plate in the second direction turns the rotatable first flattened shaft from its blocking position in its release position andthe first flattened shaft upon reaching its release position releases the fourth actuation plate which in turn is moved in the second direction by a release of the loaded second spring and as a consequence transfers the switching contact into a second switching state (e.g. closed state) or

Wherein in a Case b)

the electric switching device comprises a second blocking element, which comprises a rotatable second flattened shaft and a second lever connected to the second flattened shaft and which is designed to block the fourth actuation plate in a rotational blocking position and to release the fourth actuation plate in a rotational release position,wherein the third actuation plate or an actuating element connected thereto upon further movement of the third actuation plate contacts the second lever,wherein the third actuation plate or the actuating element upon further movement of the third actuation plate in the second direction turns the rotatable second flattened shaft from its blocking position in its release position andwherein the second flattened shaft upon reaching its release position releases the fourth actuation plate which in turn is moved in the second direction by a release of the loaded second spring and as a consequence transfers the switching contact into a second switching state (e.g. closed state).

In this embodiment, two springs and two separate actuation plates driving the switching contact are used. In particular, the actuation plates can be provided for transmitting a movement to the switching contact by a pure push function (but not with a pull function).

Beneficially the first spring and the second spring can be formed by a first part and a second part of a common spring. In this way, just a single spring is needed, wherein the first actuation plate (and eventually the fourth actuation plate) is arranged between said first and second part.

Generally, the first spring and the second spring or the first part and the second part may differ in their length and/or in their spring constant to handle opening and closing of the switching contact differently. For example, the spring, which is provided for opening the switching contact can be made stronger so as to provide a very fast opening movement. In several cases, depending on the contact type, the closing spring can be made stronger in order to create sufficient contact pressure (e.g. for butt contacts).

Advantageously, the actuating element can be embodied as an elastic actuating element and in particular can comprise an actuating element base, an actuating element spring connected to the actuating element base and an actuating element pusher. When the first actuation plate passes the first blocking element or second blocking element or when the fourth actuation plate passes the second blocking element, there may be a time period, in which a movement of the blocking elements is hindered by the actuation plates. To allow a continuous movement of the motor during this pass by or transition, the elastic actuating element is provided.

In another advantageous embodiment, the electric switching device comprises a micro switch, which is designed to interrupt a movement of the motor when the first actuation plate passes the first blocking element or when the fourth actuation plate passes the second blocking element. As stated above, a movement of the blocking elements can be hindered by an actuation plate when the first actuation plate passes the first blocking element or second blocking element or when the fourth actuation plate passes the second blocking element. in this embodiment, the motor does not continue to move but is temporarily switched off by the micro switch. For example, an actuation bump, which is coupled to the first or fourth actuation plate, can act on the micro switch. In principle, the micro switch can be embodied as opener and can be arranged between motor and a power unit. However, the micro switch can also be connected to a motor line, which leads to a control for the motor and switches off the same in this way. Once the first actuation plate has passed the first blocking element, the motor is switched on again and continues to move until its end position.

In one embodiment, the first spring and/or the second spring can be embodied as a longitudinal spring, in particular as a helical spring. Beneficially, these springs can store energy when they are linearly loaded.

In another embodiment, the first spring and/or the second spring can be embodied as a compression spring, tension spring or combined compression and tension spring. In particular, if the first spring and/or the second spring is embodied as a combined compression and tension spring, it can be used for both the first and second direction and hence for switching the switching contact into two different switching states.

In one further embodiment, the motor can be embodied as a linear motor. For example, the motor can be embodied as a pneumatic, hydraulic cylinder or a spindle motor.

DETAILED DESCRIPTION

Generally, same parts or similar parts are denoted with the same/similar names and reference signs. The features disclosed in the description apply to parts with the same/similar names respectively same/similar reference signs. Indicating the orientation and relative position is related to the associated figure, and indication of the orientation and/or relative position has to be amended in different figures accordingly as the case may be.

FIG.1shows a first example of an electric switching device1a, which comprises a switching contact2, an actuation mechanism3acoupled to the switching contact2via a switch link4and a motor5coupled to the actuation mechanism3avia a motor link6. The switching contact2, the switch link4, the motor5and the motor link6are just symbolically depicted inFIG.1and may be embodied in different variants. It should also be noted that althoughFIG.1just shows one switching contact2, the actuation mechanism3acan also move more than one switching contact2simultaneously.

For example, the motor5can be embodied as a linear motor (e.g. as a pneumatic cylinder, hydraulic cylinder or as a spindle motor) or also as a rotational motor (e.g. with a crank or a lever mounted to the motor shaft). InFIG.1, the motor5comprises a piston7movably arranged in a cylinder8. In this context it should also be noted that a spindle motor can also be seen as a rotational motor. The motor link6can be embodied as a simple rod but also can comprise a more sophisticated mechanism with rotational and/or translatory moving parts. Similarly, the switching contact2is just drawn as an electric symbol but may comprise a sophisticated mechanism and also a vacuum chamber for example. The switching contact2may be designed for low voltage, medium voltage or high voltage. Just like the motor link6, the switch link4can be embodied as a simple rod but also comprise a more sophisticated mechanism.

The actuation mechanism1comprises a first spring9, a first actuation plate10, which is connected to or contacts the first spring9and which is coupled with the switching contact2, here by means of a switch push rod11and the switch link4. Furthermore, the actuation mechanism1comprises a second actuation plate12, which is connected to or contacts the first spring9and which is coupled with the motor5, here by means of a motor push rod13and the motor link6. The second actuation plate12is spaced from the first actuation plate10with the first spring9in-between and has an optional first actuating element14a. Moreover, the actuation mechanism1comprises a first blocking element15, which comprises a rotatable first flattened shaft16(also called as “D-shaft”) and a first lever17connected to the first flattened shaft16. The first blocking element15is designed to block the first actuation plate10in a rotational blocking position and to release the first actuation plate10in a rotational release position. InFIG.1, the first blocking element15is shown in its blocking position. There may also be an optional first return spring (not shown inFIG.1but refer toFIG.7), which forces the first blocking element15into its blocking position as illustrated by means of an arrow inFIG.1.

In addition, the actuation mechanism1comprises an optional second spring18and a third actuation plate19, which is connected to or which contacts the second spring18and which is coupled with the motor5, again by means of the motor push rod13and the motor link6. The third actuation plate19is spaced from the first actuation plate10with the second spring in-between 17 and has an optional second actuating element14b. In fact, the third actuation plate19is arranged vis-à-vis of the second actuation plate12in view of the first actuation plate10. Moreover, the actuation mechanism1comprises an optional second blocking element20, which comprises a rotatable second flattened shaft21and a second lever22connected to the second flattened shaft21. The second blocking element20is designed to block the first actuation plate10in a rotational blocking position and to release the first actuation plate10in a rotational release position. InFIG.1, the second blocking element20is shown in its blocking position, too. There may also be an optional second return spring (not shown inFIG.1but refer toFIG.7), which forces the second blocking element20into its blocking position as illustrated by means of a further arrow inFIG.1.

In this embodiment, both the first spring9and the second spring19are embodied as longitudinal springs, in particular as a helical springs. However, other springs can be used as well.

FIGS.2ato2fillustrate the function of the actuation mechanism3a′, which is very similar to the actuation mechanism3aofFIG.1and which comprises an optional first stop23and an optional second stop24. Instead of two separate actuating elements14a,14b, the embodiment shown inFIGS.2ato2fcomprises a single actuating element14, however, with the same function.FIG.2ashows the electric switching device1ain an idle state as illustrated by the pause symbol.

InFIG.2b, the motor5starts to move as illustrated by the play symbol. Accordingly, the second actuation plate12and the third actuation plate19are moved in a first upward direction. As a consequence, the first spring9and the second spring18are loaded upon movement of the second actuation plate12and the third actuation plate19in the upward first direction D1. In detail, the first spring9is compressed and the second spring18is tensioned. The first actuation plate10is still blocked by the first blocking element15so that the switch push rod11does not move as it is illustrated by the stop symbol. As can be seen, the actuating element14has reached the first blocking element15inFIG.2bbut it has not yet turned it. In more detail, the actuating element14contacts the first lever17of the first blocking element15(seeFIG.1for details of the first blocking element15).

InFIG.2c, the first spring9and the second spring18have been loaded to their maximum upon further movement of the motor5. As can be seen inFIG.2c, the switch push rod11still does not move as it is illustrated by the stop symbol. However, the actuating element14has already turned the rotatable first flattened shaft16or the first blocking element15respectively from its rotational blocking position in its rotational release position. When the first flattened shaft16reaches its release position, it releases the first actuation plate10which is the case inFIG.2c. As a consequence, the first actuation plate10starts to move in the upward, first direction D1driven by a release of the loaded first spring9and the second spring18.

In the state depicted inFIG.2d, the first actuation plate10is going to pass the first flattened shaft16and continues to move as is illustrated by an arrow next to the switch push rod11. Additionally, the motor push rod13is still moved by the motor5.

InFIG.2e, the second actuation plate12and the third actuation plate19have reached their end positions after the actuating element14has reached the first stop23. The motor5is switched off in this position, for example by means of a first end switch or by detecting an overload caused by the hindered movement. Accordingly, the movement of the motor push rod13stops as is illustrated by the stop symbol. The first actuation plate10still moves and is going to pass the second flattened shaft21after it has pushed the second flattened shaft21out of its moving path. Strictly speaking, the second blocking element20is turned into its release position by the moving first actuation plate10.

InFIG.2fthe first actuation plate10has reached its end position as it is illustrated by means of the stop symbol. By the upward movement, the switch push rod11via the switch link4transfers the switching contact2into a first switching state, which in this example is the open state. The second blocking element20has moved back to its blocking position driven by the second return spring (not shown). One should note that inFIG.1and inFIGS.2ato2f(and the followingFIGS.3ato6f), the first (open) switching state and the second (closed) switching state are inversely associated to the position of the switch push rod11. That means that inFIG.1the upper position of the switch push rod11is associated with the second (closed) switching state, whereas inFIGS.2ato2fand the followingFIGS.3ato6fthe upper position of the switch push rod11is associated with first (open) switching state and vice versa.

FIG.2falso shows a second idle state, in which the position of the parts of the actuation mechanism3a′ are basically mirror inverted in view of the state depicted inFIG.2a. However, one should note for the sake of better understanding,FIG.2astrictly speaking shows a state in which the motor push rod13has already been moved upwards a bit and has already left said mirror inverted position. Because of this symmetry, switching on the switching contact2just happens like illustrated byFIGS.2ato2fbut with changed roles of the parts and inverted moving directions.

In more detail, the second actuation plate12and third actuation plate19then move in a downward, second direction D2opposite to the first direction D1by the motor5, wherein the first spring9and the second spring18upon movement of the second actuation plate12and the third actuation plate19in the second direction D2are loaded. In detail, the first spring9is tensioned and the second spring18is compressed now. Upon further movement of the second actuation plate12and the third actuation plate19, the actuating element14contacts the second lever22and upon further movement turns the rotatable second flattened shaft21. When the second flattened shaft21has turned from the blocking position into its release position, the first actuation plate10is released and in turn is moved by a release of the loaded first spring9and second spring18. As a consequence the switching contact is transferred into a second switching state, which in this example is the closed state.

By use of the first spring9and the second spring18, switching takes place very fast.

FIGS.3ato3fnow illustrate an embodiment of an actuation mechanism3b, which is similar to the actuation mechanisms3a,3a′ ofFIGS.1and2ato2f.FIG.3arelates toFIG.2a,FIG.3btoFIG.3band so forth. As can be seen, the actuation mechanism3bcomprises just a first spring9and no third actuation plate19. Nevertheless, the function of the actuation mechanism3bis very similar to that of actuation mechanisms3a,3a′ and almost equals the function of the actuation mechanisms3a,3a′. Basically, the only difference is the missing effect of the non-existing second spring18and the missing effect of the non-existing third actuation plate19.

FIGS.4ato4fillustrate an embodiment of an actuation mechanism3c, which is similar to the actuation mechanisms3a,3a′ ofFIGS.1and2ato2f, too.FIG.4arelates toFIG.2a,FIG.4btoFIG.2band so forth. As can be seen, the switch push rod11is not fixedly be mounted to the first actuation plate10, but in principle it may freely move between the first actuation plate10fixed to the first spring9and a fourth actuation plate25fixed to the second spring18. Nevertheless, the function of the actuation mechanism3cis very similar to that of actuation mechanisms3a,3a′ and almost equals the function of the actuation mechanisms3a,3a′. Basically, the only difference is that the first actuation plate10and the fourth actuation plate25can only push the switch push rod11(and not pull it like the first actuation plate10of actuation mechanisms3a,3a′ does) and that accordingly there is no tension of the first spring9and second spring18. Moreover, the position of the switch push rod11is not linked to the position of the first actuation plate10(like this is the case in the actuation mechanisms3a,3a′) but linked to the position first actuation plate10or to the fourth actuation plate25.

FIGS.5ato5fillustrate an embodiment of an actuation mechanism3d, which is similar to the actuation mechanisms3a,3a′ ofFIGS.1and2ato2fagain.FIG.5arelates toFIG.2a,FIG.5btoFIG.2band so forth. As can be seen, the actuation mechanism3ddoes not comprise a second blocking element20but just a first blocking element15. Moreover, the actuating elements14a,14bare different. In detail, the actuation mechanism3dhas a first actuating element14a′, which comprises a first actuating element base26a, a first actuating element spring27aconnected to the first actuating element base26aand a first actuating element pusher28aconnected to the first actuating element spring27a. Similarly, the actuation mechanism3dhas a second actuating element14b′, which comprises a second actuating element base26b, a second actuating element spring27bconnected to the second actuating element base26band a second actuating element pusher28bconnected to the second actuating element spring27b. However, the function of the actuation mechanism3dagain is similar to that of actuation mechanisms3a,3a′. In contrast, the first blocking element15blocks the movement of the first actuation plate10both in the upward first direction D1and in the downward second direction D2until it is turned by the first actuating element14a′ or second actuating element14b′. One further difference is that the movement of the motor push rod13is not stopped when the first actuating element14areaches the first stop23or when the second actuating element14breaches the second stop24but when the first actuating element14a′ (strictly speaking its first actuating element base26a) or the second actuating element14b′ (strictly speaking its second actuating element base26b) reaches the first flattened shaft16of the first blocking element15. In these positions, the motor5is switched off, for example by means of end switches or by detecting an overload caused by the hindered movement.

The reason for the provision of the elastic first actuating element14a′ and the elastic second actuating element14b′ is explained by useFIGS.5bto5f. It should be noted that the first actuating element spring27aand the second actuating element spring27b(or other equivalent elastic elements) are designed in a way that the first blocking element15can be turned without considerable compression of the first actuating element spring27aand the second actuating element spring27b. Accordingly, the first blocking element15starts to rotate inFIG.5band continues to rotate until the position depicted inFIG.5c. Because the first blocking element15releases the first actuation plate10, the first actuation plate10starts to move upwards and hinders a further rotation of the first blocking element15until the first actuation plate10has passed the same. This blocking situation is depicted inFIG.5d. However, to (better) allow a continuous movement of the motor5during this pass by or transition, the elastic first actuating element14a′ and the elastic second actuating element14b′ are provided. As can be seen inFIG.5d, the first actuating element spring27ahas been compressed, or in other words the first actuating element base26ahas been moved by the motor5, whereas the first actuating element pusher28ahas not moved. After the first actuation plate10has passed the first blocking element15, the first actuating element spring27arelaxes again. This situation is depicted inFIG.5e. InFIG.5f, the motor push rod13has reached its end position. When the motor5moves the motor push rod13downward in the second direction D2, things are just the other way around.

FIGS.6ato6fillustrate an embodiment of an actuation mechanism3e, which is similar to the actuation mechanisms3dofFIGS.5ato5f.FIG.6arelates toFIG.5a,FIG.6btoFIG.5band so forth. In contrast, the actuation mechanism3ehas rigid actuating elements14a,14bagain like the actuation mechanism3aofFIG.1has. A further difference is that actuation mechanism3ecomprises a micro switch29, a motor line30leading to the motor5and an actuation bump31. Like inFIG.5d, a blocking situation inFIG.6dis taken into consideration, where the first blocking element15cannot be turned further by the motor5. However, in this embodiment, the motor5does not continue to move but is temporarily switched off by the micro switch29. As can be seen inFIG.6d, the actuation bump31acts on the micro switch29in this state. In principle, the micro switch29can be embodied as opener and can be arranged between the motor5and a power unit for the motor5. However, the motor line30can also be a control line leading to a control for the motor5. Once the first actuation plate10has passed the first blocking element15, the motor5is switched on again as depicted inFIG.6eand continues to move until its end position depicted inFIG.6f.

It should be noted that the elastic actuating elements14a′,14b′ ofFIGS.5ato5fand/or the micro switch29ofFIGS.6ato6fcan be applied to the actuation mechanisms3a. . .3cofFIGS.1to4fin an equivalent way because similarly said blocking situation can be taken into consideration there. It should also be noted that the first blocking element15may simply be denoted as “blocking element15” in the embodiments ofFIGS.5ato5fand6ato6fbecause there is just one in these embodiments.

Furthermore, one should note that the embodiments ofFIG.1,FIG.2a. . .2fandFIG.4a. . .6fare symmetric with respect to the springs9and18. However, this is no necessary condition and the springs9and18may be embodied differently, in particular in view of their length and/or spring constant. Accordingly, switching on and off can take place differently in alternative embodiments.

FIG.7now shows a more detailed example of an electric switching device1b, which comprises an actuating mechanism3fof the type shown inFIG.1andFIG.2a. . .2f, however with a differently shaped push rod11b. The push rod11bis coupled to a pivoted lever32, which is pivotally mounted in a frame (not shown inFIG.7) by use of a bearing33in this embodiment. A switching frame34is connected to the lever32, too. The switching frame34is also connected to a number of switching caps35, which can be moved on a switch base36simultaneously (here in horizontal direction). The switching caps35and the switch bases36are parts of a number of switches37, which are mounted to a common frame38.FIG.7also shows terminals39for connecting the electric switching device1bto a grid.

In each switch base36there is a fixed contact, and in each switching cap35there is a movable contact. When the push rod11bis moved upwards in the first direction D1, the switching frame34together with the switching caps35is moved from the right to the left thus closing the switching contacts2. When the push rod11bis moved downwards in the second direction D2, the switching frame34together with the switching caps35is moved from the left to the right thus opening the switching contacts2. For example, the electric switching device1bcan be embodied as three-phase switching device.

In the lower left corner,FIG.7in addition shows a detailed view of the trigger mechanism comprising the first blocking element15and the second blocking element20. In addition to the parts already known fromFIG.1,FIG.7explicitly depicts a first return spring40, which forces the first blocking element15into its rotational blocking position, and a second return spring41, which forces the second blocking element20into its rotational blocking position.

As can be realized fromFIG.7the actuation mechanism3fis very slim. That is why it is particularly suitable for retrofitting switch arrangements, which are manually operated originally and where space is limited. In a real application of the electric switching device1bofFIG.7, a door of a switch gear (not shown) may be arranged just right of the switching frame34. By use of the pivoted lever32, the actuation mechanism3fcan be arranged right below the switch arrangement, where often space is left in real applications.

In reality, the electric switching device1a,1band the actuation mechanisms3a. . .3fmay have more or less parts than shown in the figures. Moreover, the description may comprise subject matter of further independent embodiments.

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