EP4030455A1

EP4030455A1 - A medium voltage switching apparatus

Info

Publication number: EP4030455A1
Application number: EP21151587.9A
Authority: EP
Inventors: Giorgio Forlani; Corrado Rizzi; Emanuele Morelli; Jacopo Bruni
Original assignee: ABB Schweiz AG
Current assignee: ABB Schweiz AG
Priority date: 2021-01-14
Filing date: 2021-01-14
Publication date: 2022-07-20

Abstract

A switching apparatus for medium voltage electric systems, said switching apparatus comprising one or more electric poles, wherein, for each electric pole, said switching apparatus comprises:
- a first pole terminal, a second pole terminal and a ground terminal, said first pole terminal being electrically couplable with a first conductor of an electric line, said second pole terminal being electrically couplable to a second conductor of said electric line and said ground terminal being electrically couplable to a grounding conductor;
- a first contact arrangement including a first fixed contact member and a first movable contact member, said first fixed contact member being electrically connected to said first pole terminal and including a first fixed contact, said first movable contact member being electrically connected to said second pole terminal and including a first movable contact, said first movable contact member being reversibly movable along a translation axis, so that said first movable contact can be coupled with or decoupled from said first fixed contact;
- a second contact arrangement including a second fixed contact member and a second movable contact member, said second fixed contact member being electrically connected to said ground terminal and including a second fixed contact, said second movable contact member being electrically connected to said second pole terminal and including a second movable contact, said second movable contact member being reversibly movable about a corresponding rotation axis, so that said second movable contact can be coupled to or decoupled from said second fixed contact;
- an actuation assembly for actuating the first and second movable contact members of each electric pole during a switching manoeuvre of said switching apparatus, said actuation assembly including an actuation shaft reversibly movable about a corresponding rotation axis;
- a motion transmission assembly for transmitting mechanical forces provided by said actuation shaft to the first and second movable contact members of each electric pole.

Description

The present invention relates to a switching apparatus for medium voltage electric systems, more particularly to a load-break switch for medium voltage electric systems.
Load-break switches are well known in the state of the art.
These switching apparatuses, which are generally used in secondary distribution electric grids, are capable of providing both circuit-breaking functionalities (namely breaking and making a current) under specified circuit conditions (typically nominal or overload conditions) and circuit-disconnecting functionalities (namely grounding a load-side section of an electric circuit).
Most traditional load-break switches of the state of the art have multiple actuation shafts and actuators to actuate the movable contacts of the electric poles. Thus, these switching apparatuses generally have a relatively complex structure, which is quite cumbersome and expensive to manufacture at industrial level.
Additionally, many load-break switches of the state of the art have their electric poles immersed in a sulphur hexafluoride (SF6) atmosphere as this insulating gas ensures excellent performances in terms of dielectric insulation between live parts and optimal arc-quenching capabilities when currents are interrupted. As is known, however, SF6 is a powerful greenhouse gas. These switching apparatuses therefore have a relatively high environmental impact, which is no more acceptable in view of the most recent regulations committing to environmental protection.
The main aim of the present invention is to provide a switching apparatus for medium voltage electric systems that allows solving or mitigating the above-mentioned technical problems. More particularly, it is an object of the present invention to provide a switching apparatus having high structural compactness and simplicity.
Another object of the present invention is to provide a switching apparatus having a relatively low environmental impact.
Another object of the present invention is to provide a switching apparatus showing high levels of reliability in operation.
Another object of the present invention is to provide a switching apparatus that can be easily manufactured at industrial level, at competitive costs with respect to the solutions of the state of the art.
In order to fulfill these aim and objects, the present invention provides a switching apparatus, according to the following claim 1 and the related dependent claims.
In a general definition, the switching apparatus of the invention comprises one or more electric poles.
For each electric pole, the switching apparatus comprises a first pole terminal, a second pole terminal and a ground terminal. In operation, the first pole terminal is electrically coupled to a first conductor of an electric line, the second pole terminal is electrically coupled to a second conductor of said electric line and the ground terminal is electrically coupled to a grounding conductor.
For each electric pole, the switching apparatus comprises a first contact arrangement including a first fixed contact member and a first movable contact member.
The first fixed contact member is electrically connected to the first pole terminal and it includes a first fixed contact.
The first movable contact member is electrically connected to the second pole terminal and it includes a first movable contact.
The first movable contact member is reversibly movable along a corresponding translation axis. In this way, the first movable contact can be coupled to or uncoupled from the first fixed contact. For each electric pole, the switching apparatus comprises a second contact arrangement including a second fixed contact member and a second movable contact member.
The second fixed contact member is electrically connected to the ground terminal and it includes a second fixed contact.
The second movable contact member includes a second movable contact and is reversibly movable along a corresponding rotation axis. In this way, the second movable contact can be coupled to or decoupled from the second fixed contact.
The switching apparatus, according to the invention, comprises also an actuation assembly for actuating the first and second movable contact members of each electric pole during a switching manoeuvre. Said actuation assembly conveniently includes an actuation shaft reversibly movable about a corresponding rotation axis.
The switching apparatus, according to the invention, further comprises a motion transmission assembly for transmitting mechanical forces provided by said actuation assembly to the first and second movable contact members of each electric pole.
According to the invention, said motion transmission assembly comprises a first motion transmission member coupled to said actuation shaft to be actuated by the rotational mechanical forces provided by said actuation shaft. In operation, upon actuation by said actuation shaft, said first motion transmission member is reversibly movable about a first rotation axis, namely according to a first rotation direction or according to a second rotation direction, opposite to said first rotation direction,
According to the invention, said motion transmission assembly comprises a second motion transmission member couplable with said first motion transmission member to be actuated by rotational mechanical forces provided by said first motion transmission member. In operation, upon actuation by first second motion transmission member, said second motion transmission member is reversibly movable about a second rotation axis parallel to said first rotation axis, namely according to a third rotation direction or according to a fourth rotation direction, opposite to said third rotation direction.
According to the invention, said motion transmission assembly comprises a first motion transmission shaft coupled with said second motion transmission member to be actuated by rotational mechanical forces provided by said second motion transmission member. According to the invention, said motion transmission assembly comprises, for each electric pole, a motion transmission mechanism coupled to said first motion transmission shaft and to said first movable contact member of each electric pole. In operation, said motion transmission mechanism is actuated by rotational mechanical forces provided by said first motion transmission shaft and it transmits translational mechanical forces to each first movable contact member to actuate said first movable contact member.
According to the invention, said motion transmission assembly comprises a third motion transmission member couplable with said first motion transmission member to be actuated by rotational mechanical forces provided by said first motion transmission member. In operation, upon actuation by said first motion transmission member, said third motion transmission member is reversibly movable about a third rotation axis parallel to said first rotation axis, namely according to a fifth rotation direction or according to a sixth rotation direction, opposite to said fifth rotation direction.
According to the invention, said motion transmission assembly comprises a second motion transmission shaft coupled with said third motion transmission member to be actuated by rotational mechanical forces provided by said third motion transmission member. The second motion transmission member is coupled with the second movable contact member of each electric pole. In operation, said second motion transmission shaft transmits the rotational mechanical forces provided by said third motion transmission member to each second movable contact member to actuate said second movable contact member.
According to an aspect of the invention, in operation, said first motion transmission member couples with and actuates said second and third motion transmission members alternately to each other, while said first motion transmission member moves between opposite end-of-run positions according to said first rotation direction or said second rotation direction. Preferably, said first motion transmission member couples with and actuates said second and third motion transmission members sequentially to each other, while said first motion transmission member moves between opposite end-of-run positions according to said first rotation direction or said second rotation direction.
According to an aspect of the invention, said first motion transmission member comprises a first engaging pin and a second engaging pin protruding from at least a surface of said first motion transmission member. Said first and second engaging pins are angularly spaced one from another with respect to the first axis of rotation of said first motion transmission member. Preferably, said first and second engaging pins protrude from opposite surfaces of said first motion transmission member.
According to an aspect of the invention, said second motion transmission member comprises a first engaging slot extending radially with respect to the second axis of rotation of said second motion transmission member. In operation, the first engaging pin of said first motion transmission member is engageable with said first engaging slot.
According to an aspect of the invention, said third motion transmission member comprises a second engaging slot extending radially with respect to the third axis of rotation of said third motion transmission member. In operation, the second engaging pin of said first motion transmission member is engageable with said second engaging slot.
According to some embodiments of the invention, said motion transmission assembly comprises a first end-of-run pin and a second end-of-run pin fixed to a support member of said switching apparatus.
Said first end-of-run pin is coupled with a first end-of-run slot of said second motion transmission member and, in operation, it slides along said first end-of-run slot when said second motion transmission member moves about said second rotation axis.
Said second end-of-run pin is coupled with a second end-of-run slot of said third motion transmission member and, in operation, it slides along said second end-of-run slot when said third motion transmission member moves about said third rotation axis.
According to other embodiments of the invention, said first motion transmission member comprises a first end-of-run surface and a second end-of-run surface, which are configured for coupling with third end-of-run surfaces of the second motion transmission member and with fourth end-of-run surfaces of the third motion transmission member, respectively.
In operation, depending on the rotation direction of the above-mentioned motion transmission members, the first end-of-run surface of the first motion transmission member couples with one of the third end-of-run surfaces of the second motion transmission member while the second end-of-run surface of the first motion transmission member couples with one of the fourth end-of-run surfaces of the third motion transmission member.
Further characteristics and advantages of the invention will emerge from the description of preferred, but not exclusive embodiments of the switching apparatus, according to the invention, non-limiting examples of which are provided in the attached drawings, wherein:

Figures 1-4 are schematic views partially showing an embodiment of the switching apparatus, according to the invention;
Figures 5-7 are schematic views showing operation of the switching apparatus of Figs. 1-4;
Figures 8-9 are schematic views partially showing some parts of the switching apparatus of Figs. 1-4;
Figures 10-11 are schematic views partially showing some parts of a variant embodiment of the switching apparatus, according to the invention.

With reference to the figures, the present invention relates to a switching apparatus 1 for medium voltage electric systems.
For the purpose of the present application, the term "medium voltage" (MV) relates to operating voltages at electric power distribution level, which are higher than 1 kV AC and 1.5 kV DC up to some tens of kV, e.g. up to 72 kV AC and 100 kV DC.
The switching apparatus 1 is particularly adapted to operate as a load-break switch. It is therefore designed for providing circuit-breaking functionalities under specified circuit conditions (nominal or overload conditions) as well as circuit-disconnecting functionalities, in particular grounding a load-side section of an electric circuit.
The switching apparatus 1 comprises one or more electric poles 2.
Preferably, the switching apparatus 1 is of the multi-phase (e.g. three-phase) type and it therefore comprises a plurality (e.g. three) of electric poles 2.
Preferably, the switching apparatus 1 comprises an insulating housing 4, which conveniently defines an internal volume where the electric poles 2 are accommodated.
Preferably, the insulating housing 4 has an elongated shape (e.g. substantially cylindrical) developing along a a main longitudinal axis 100 of the switching apparatus (figure 1).
Preferably, the electric poles 2 are arranged side by side along corresponding transversal planes perpendicular the main longitudinal axis 100 of the switching apparatus. Conveniently, the insulating housing has opposite shaped transversal protrusions at each electric pole 2 to accommodate the components of said electric pole.
In general, the insulating housing 4 of the switching apparatus may be realized according to solutions of known type. Therefore, in the following, it will be described only in relation to the aspects of interest of the invention, for the sake of brevity.
Preferably, the internal volume of the switching apparatus 1 is filled with air or another insulating gas having a low environmental impact, such as such as mixtures of oxygen, nitrogen, carbon dioxide and/or fluorinated gases.
For each electric pole 2, the switching apparatus 1 comprises a first pole terminal 11, a second pole terminal 12 and a ground terminal 13.
The first pole terminal 11 is adapted to be electrically coupled to a first conductor of an electric line (e.g. a phase conductor electrically connected to an equivalent electric power source), the second pole terminal 12 is adapted to be electrically connected to a second conductor of an electric line (e.g. a phase conductor electrically connected to an equivalent electric load) while the ground terminal 13 is adapted to be electrically connected to a grounding conductor 130 (figures 3-4).
In general, the pole terminals 11, 12, 13 of the electric poles of the switching apparatus may be realized according to solutions of known type. Therefore, in the following, they will be described only in relation to the aspects of interest of the invention, for the sake of brevity. According to the invention, for each electric pole 2, the switching apparatus 1 comprises a first contact arrangement 5, 5A, 6, 6A, 7.
Such a first contact arrangement comprises an electrically conductive first fixed contact member 5A including at least a first fixed contact 5.
Each first fixed contact member 5A is at least partially made of an electrically conductive material and it is electrically connected to a corresponding first pole terminal 11. As shown in cited figures, each first fixed contact member 5A may be conveniently formed by an elongated tubular piece of conductive material having one end coupled to the first pole terminal 11 and an opposite end forming the first fixed contact 5.
In principle, however, the first fixed contact members 5A may be realized according to other solutions of known type (e.g. according to a blade configuration), which are here not described in details for the sake of brevity.
The above-mentioned first contact arrangement comprises a first movable contact member 6A including at least a first movable contact 6.
Each first movable contact member 6A is at least partially made of an electrically conductive material and it is electrically connected to the second pole terminal 12 of the corresponding electric pole by means of suitable conductors 120A (e.g. of the braid type - figures 3-4).
Each first movable contact member 6A is reversibly movable along a corresponding translation axis A, preferably laying on a transversal plane substantially perpendicular to the main longitudinal axis 100 of the switching apparatus.
Each first movable contact member 6A can translate according to a first translation direction D1, which is oriented away from the first fixed contact 5, or according to a second translation direction D2, which is opposite to the first translation direction D1 and is oriented towards the first fixed contact 5 (figure 5).
As it will better illustrated in the following, each first movable contact member 6A moves according to the first translation direction D1 during an opening manoeuvre of the switching apparatus and it moves according to the second translation direction D2 during a closing manoeuvre of the switching apparatus.
As the corresponding first movable contact member 6A is reversibly movable along the first translation axis A, each first movable contact 6 can be coupled to or uncoupled from the corresponding first fixed contact 5.
As shown in cited figures, each first movable contact member 6A is preferably formed by a tubular element of conductive material.
In principle, however, the first movable contact member 6A may be realized according to other solutions of known type (e.g. according to a doble-blade configuration including a double movable contact), which are here not described in details for the sake of brevity.
Preferably, as shown in the cited figures, the first contact arrangement of each electric pole 2 has an arc-quenching puffer configuration (which may be of known type).
For example, as shown in the cited figures, each electric pole 2 may conveniently comprise an arc chamber 7A (e.g. having a cylindrical shape) accommodating the first movable contact member 6A and the first fixed contact member 5A. Each first movable contact member 6A may be solidly coupled to a puffer piston assembly 7 so as to move together with this latter along the arc chamber 7A. In this way, during an opening manoeuvre of the switching apparatus, a pressurized flow of insulation gas can thus be blown in the gap between each first fixed contact 5 and the corresponding first movable contact 6 thereby extinguishing the electrical arcs arising due to the separation of these electric contacts.
According to the invention, for each electric pole 2, the switching apparatus 1 comprises a second contact arrangement.
Such a second contact arrangement comprises a second fixed contact member 8A including at least a second fixed contact 8.
Each second fixed contact member 8A is at least partially made of an electrically conductive material and it is electrically connected to the ground terminal 13. As shown in cited figures, each second fixed contact member 8A is preferably formed by a shaped piece of conductive material coupled to the ground terminal 13 and having a blade portion forming the second fixed contact 8.
In principle, however, the second fixed contact members 8A may be realized according to other solutions of known type (e.g. according to a double blade configuration), which are here not described in details for the sake of brevity.
The second contact arrangement 102 comprises a second movable contact member 9A including at least a second movable contact 9.
Each second movable contact member 9A is at least partially made of an electrically conductive material and it is electrically connected to the second pole terminal 12 of the corresponding electric pole by means of suitable conductors 120B (e.g. of the braid type - figures 3-4).
Each second movable contact member 9A is reversibly movable about a corresponding rotation axis A3 according to opposite rotation directions R5 or R6, which is preferably parallel to the main longitudinal axis 100 of the switching apparatus.
As it will better illustrated in the following, each second movable contact member 9A moves according to the rotation direction R5 during a disconnecting manoeuvre of the switching apparatus and it moves according to the rotation direction R6 during a reconnecting manoeuvre of the switching apparatus.
As the corresponding second movable contact member 8A is reversibly movable about the rotation axis A3, each second movable contact 9 can be coupled to or uncoupled from the corresponding second fixed contact 8.
As shown in cited figures, each second movable contact member 9A is preferably formed by a pair of blades of conductive material, each having one end coupled to a further mechanical element 66 and an opposite free end forming a second movable contact 9.
In principle, however, the second movable contact members 9A may be realized according to other solutions of known type (e.g. according to a single blade configuration), which are here not described in details for the sake of brevity.
According to the invention, the switching apparatus 1 comprises an actuation assembly providing suitable actuation forces to actuate the movable contact members 6A, 9A of the electric poles.
Conveniently, the actuation assembly 3 comprises a single actuation shaft 52 (preferably made of electrically insulating material), which can move about a corresponding rotation axis A1 parallel to the main longitudinal axis 100 of the switching apparatus.
The motion transmission shaft 52 therefore provides rotational mechanical forces to actuate the first movable contact members 6A, 9A of the electric poles.
Preferably, the actuation assembly 3 comprises a single actuator 51 coupled to the actuation shaft 52 through a suitable kinematic chain or other equivalent mechanical couplings. The actuator 51 may be, for example, a mechanical actuator, an electric motor or an electromagnetic actuator.
In general, the actuation assembly of the switching apparatus may be realized according to solutions of known type. Therefore, in the following, it will be described only in relation to the aspects of interest of the invention, for the sake of brevity.
According to the invention, the switching apparatus 1 comprises a motion transmission assembly for transmitting the rotational mechanical forces provided by the actuation assembly to the first and second movable contact members 6A, 9A of the electric poles.
According to the invention, the above-mentioned motion transmission assembly comprises a first motion transmission member 61, which is coupled to the actuation shaft 52 in such a way to be actuated by the rotational mechanical forces provided by this latter.
Upon actuation by said actuation shaft 52, the first motion transmission member 61 can reversibly move about a first rotation axis A1, which is conveniently parallel to the main longitudinal axis 100 of the switching apparatus.
In particular, the first motion transmission member 61 is movable about the first rotation axis A1 according to a first rotation direction R1 or according to a second rotation direction R2, opposite to said first rotation direction (figure 5).
With reference to an observation plane of figure 5, the above-mentioned first rotation direction R1 is oriented clockwise while the above-mentioned second rotation direction R2 is oriented counter-clockwise.
As it will better illustrated in the following, the first motion transmission member 61 moves according to the first rotation direction R1 during an opening manoeuvre or a disconnecting manoeuvre of the switching apparatus and it moves according to the second rotation direction R2 during a reconnecting manoeuvre or a closing manoeuvre of the switching apparatus. Preferably, as shown in the cited figures, the first motion transmission member 61 is solidly coupled with the actuation shaft 52 so as to move together with this latter about a same first rotation axis A1.
According to other embodiments of the invention (not shown), however, the first motion transmission member 61 may be coupled to the actuation shaft 52 through a gear mechanism or other mechanical couplings of equivalent type.
In general, the first motion transmission member 61 comprises suitable engaging means configured in such a way to allow a transitory mechanical coupling with further motion transmission members 62, 65.
Preferably, the first motion transmission member 61 comprises a first engaging pin 611 and a second engaging pin 612 protruding from at least a surface 611A, 612A and angularly spaced one from another with respect to the first axis of rotation A1.
Preferably, the first and second engaging pins 611, 612 protrude from opposite surfaces 611A, 612A of the first motion transmission member 61 (figures 8-11).
As better illustrated in the following, this solution allows reducing the overall size of the first motion transmission member 61 and, more generally, of the overall motion transmission assembly of the switching apparatus.
Preferably, as shown in the cited figures, the first motion transmission member 61 is made by a solid wheel having the first and second engaging pins 61, 62 on opposite surfaces 611A, 612A. According to some embodiments of the invention (not shown), however, the first motion transmission member 61 may have a different shape. As an example, it may be shaped as a wheel angular sector provided the above-mentioned first and second engaging pins on opposite surfaces.
According to other embodiments of the invention (not shown), the first motion transmission member 61 may be even formed by a pair of arms solidly connected one to another to rotate about the first rotation axis and provided with the above-mentioned the first and second engaging pins on opposite sides.
According to further embodiments of the invention (not shown), the first motion transmission member 61 may not comprise the above-mentioned engaging pins. For example, it may be formed by a gear wheel having suitable toothed surfaces angularly spaced one from another with respect to the first axis of rotation A1 (instead of the above-mentioned engaging pins). According to the invention, the above-mentioned motion transmission assembly comprises a second motion transmission member 62, which is couplable with the first motion transmission member 61 to be actuated by the rotational mechanical forces provided by this latter.
Upon actuation by the first motion transmission member 61, the second motion transmission member 62 can reversibly move about a second rotation axis A2, which is conveniently parallel to the first rotation axis A1.
In particular, the second motion transmission member 62 is movable about the second rotation axis A2 according to a third rotation direction R3 or according to a fourth rotation direction R4, opposite to said third rotation direction (figure 5).
With reference to an observation plane of figure 5, the above-mentioned third rotation direction R3 is oriented counter-clockwise while the above-mentioned fourth rotation direction R3 is oriented clockwise.
As it will better illustrated in the following, the second motion transmission member 62 moves according to the third rotation direction R3 during an opening manoeuvre of the switching apparatus and it moves according to the fourth rotation direction R4 during a closing manoeuvre of the switching apparatus.
In general, the second motion transmission member 62 comprises suitable engaging means configured in such a way to obtain a transitory mechanical coupling with the first motion transmission member 61.
Preferably, the second motion transmission member 62 comprises a first engaging slot 621 extending radially with respect to the second axis of rotation A2 in such a way to be accessible at an external edge 625 of the second motion transmission member 62.
The first and second motion transmission members 61, 62 are positioned relative each other so that the first engaging pin 611 of the first motion transmission member 61 engages the second motion transmission member 62 at the first engaging slot 621 upon a suitable movement of said first motion transmission member.
In particular, upon a suitable movement of the first motion transmission member according to a given rotation direction R1 or R1, the first engaging pin 611 engages the first engaging slot 621, slides along the first engaging slot 621 according to opposite radial directions and finally decouples from the first engaging slot 621.
Obviously, the first motion transmission member 61 actuates the second motion transmission member 62 during the time interval in which the first engaging pin 611 engages the first engaging slot 621, thereby coupling the first motion transmission member 61 with the second motion transmission 62.
It is evident from the above that, according to the embodiment shown in the cited figures, the first and second motion transmission members 61, 62 are arranged in such a way to form a first motion transmission mechanism of the Geneva type (Maltese motion transmission mechanism) for transmitting the actuation forces imparted by the actuation shaft 52 to the first movable contact member 6A of each electric pole.
Preferably, the second motion transmission member 62 is positioned at the side (surface 611A) of the first motion transmission member 61, from which the first engaging pin 611 protrudes. Preferably, as shown in the cited figures, the second motion transmission member 62 is made by a solid wheel sector having the first engaging slot 621 at an external edge 625.
According to some embodiments of the invention (not shown), the second motion transmission member 62 may have a different shape, for example as a solid wheel.
According to further embodiments of the invention (not shown), when the first motion transmission member 61 is formed by a gear wheel, the second motion transmission member 62 may be a gear wheel having (instead of the above-mentioned engaging slot) a suitable toothed surface engageable by a corresponding suitable toothed surface of the first motion transmission member 61.
According to the invention, the above-mentioned motion transmission assembly comprises a first motion transmission shaft 63 coupled with the second motion transmission member 62 to be actuated by the rotational mechanical forces provided by this latter.
In general, the first motion transmission shaft 63 extends along a direction coinciding or parallel to the second rotation axis A2 of the second motion transmission member 62. Preferably, as shown in the cited figures, the first motion transmission shaft 63 is solidly coupled with the second motion transmission member 62 in such a way to move together with this latter about the second rotation axis A2, according to the rotation directions R3 or R4.
According to other embodiments of the invention (not shown), however, the first motion transmission shaft 63 may be coupled to the second motion transmission member 62 through a gear mechanism or other equivalent mechanical couplings.
According to the invention, the above-mentioned motion transmission assembly comprises, for each electric pole 2, a motion transmission mechanism 64 coupled to the first motion transmission shaft 63 and to the first movable contact member 6A of each electric pole.
In general, each motion transmission mechanism 64 is arranged in such a way that it is actuated by the rotational mechanical forces provided by the first motion transmission shaft 63 and it transmits translational mechanical forces to the corresponding first movable contact member 6A to actuate this latter according to the translation directions D1, D2.
In practice, each motion transmission mechanism 64 is arranged in such a way to convert the rotational mechanical forces provided by the first actuation shaft 62 into translational mechanical forces for actuating the corresponding first movable contact member 6A. Preferably, as shown in the cited figures, each motion transmission mechanism 64 is formed by a crank-lever mechanism coupled to the first motion transmission shaft 63 and to the first movable contact member 6A of each electric pole.
According to other embodiments of the invention (not shown), however, each motion transmission mechanism 64 may be configured differently, for example as a cam mechanism. According to the invention, the above-mentioned motion transmission assembly comprises a third motion transmission member 65, which is couplable with the first motion transmission member 61 to be actuated by the rotational mechanical forces provided by this latter.
Upon actuation by the first motion transmission member 61, the third motion transmission member 65 is reversibly movable about a third rotation axis A3, which is conveniently parallel to the first rotation axis A1.
In particular, the third motion transmission member 65 is movable about the third rotation axis A3 according to a fifth rotation direction R5 or according to a sixth rotation direction R6, opposite to said fifth rotation direction (figure 5).
With reference to an observation plane of figure 5, the above-mentioned fifth rotation direction R5 is oriented counter-clockwise while the above-mentioned sixth rotation direction R6 is oriented clockwise.
As it will better illustrated in the following, the third motion transmission member 65 moves according to the fifth rotation direction R5 during a disconnecting manoeuvre of the switching apparatus and it moves according to the sixth rotation direction R6 during a reconnecting manoeuvre of the switching apparatus.
In general, the third motion transmission member 65 comprises suitable engaging means configured in such a way to obtain a transitory mechanical coupling with the first motion transmission member 61.
Preferably, the third motion transmission member 65 comprises a second engaging slot 651 extending radially with respect to the third axis of rotation A3 in such a way to be accessible at an external edge 655 of the third motion transmission member 65.
Preferably, the first and third motion transmission members 61, 65 are positioned relative each other so that the second engaging pin 612 of the first motion transmission member 61 engages the third motion transmission member 65 at the second engaging slot 651 upon a suitable movement of said first motion transmission member.
In particular, upon a suitable movement of the first motion transmission member according to a given rotation direction R1 or R1, the second engaging pin 612 engages the second engaging slot 651, slides along the second engaging slot 651 according to opposite radial directions and finally decouples from the second engaging slot 651.
Obviously, the first motion transmission member 61 actuates the third motion transmission member 65 during the time interval in which the second engaging pin 612 engages the second engaging slot 651, thereby coupling the first motion transmission member 61 with the third motion transmission member 65.
It is evident from the above that, according to the embodiments shown in the cited figures, the first and third motion transmission members 61, 65 are arranged in such a way to form a second motion transmission mechanism of the Geneva type (Maltese motion transmission mechanism) for transmitting the actuation forces imparted by the actuation shaft 52 to the second movable contact member 9A of each electric pole.
Preferably, the third motion transmission member 65 is positioned at the side (surface 612A) of the first motion transmission member 61, from which the second engaging pin 612 protrudes. Preferably, as shown in the cited figures, the third motion transmission member 65 is made by a solid wheel sector having the second engaging slot 651 at an external edge 655.
According to some embodiments of the invention (not shown), the third motion transmission member 65 may have a different shape, for example as a solid wheel.
According to further embodiments of the invention (not shown), when the first motion transmission member is formed by a gear wheel, the third motion transmission member 65 may be a gear wheel having (instead of the above-mentioned engaging slot) a suitable toothed surface engageable by a corresponding suitable toothed surface of the first motion transmission member 61.
According to the invention, the above-mentioned motion transmission assembly comprises a second motion transmission shaft 66 coupled with the third motion transmission member 65 to be actuated by the rotational mechanical forces provided by this latter.
In general, the second motion transmission shaft 66 extends along a direction coinciding or parallel to the third rotation axis A3 of the third motion transmission member 65.
The second motion transmission shaft 66 is coupled with the second movable contact member 9A of each electric pole 2. In this way, upon actuation by the third motion transmission member 65, the second motion transmission shaft 66 transmits the rotational mechanical forces provided by the third motion transmission member 65 to the second movable contact member 9A of each electric pole to actuate said first movable contact member.
Preferably, as shown in the cited figures, the second motion transmission shaft 66 is solidly coupled with the third motion transmission member 65 in such a way to move together with this latter about the third rotation axis A3, according to the rotation direction R5 or R6. According to other embodiments of the invention (not shown), however, the second motion transmission shaft 66 may be coupled to the third motion transmission member 65 through a gear mechanism or other equivalent mechanical couplings.
In general, the motion transmission assembly of the switching apparatus comprises end-of-run means configured in such a way to prevent extra movements of the second and third motion transmission members 62, 65 after decoupling from the first motion transmission member 61.
According to some embodiments of the invention (figures 8-9), the above-mentioned motion transmission assembly comprises a first end-of-run pin 67 and a second end-of-run pin 68 fixed to a support member of the switching apparatus, for example the insulating casing 4.
The first end-of-run pin 67 is coupled with a first end-of-run slot 622 of the second motion transmission member 62, which is conveniently arranged along a circumference arc about the second rotation axis A2.
In operation, the first end-of-run pin 67 slides along the first end-of-run slot 622 when the second motion transmission member 62 moves about the second rotation axis A2. The sliding direction of the first end-of-run pin 67 depends on the rotation direction R3 or R4 of the second motion transmission member 62.
The second end-of-run pin 68 is coupled with a second end-of-run slot 652 of the third motion transmission member 65, which is conveniently arranged along a circumference arc about the third rotation axis A3.
In operation, the second end-of-run pin 68 slides along the second end-of-run slot 652 when the third motion transmission member 65 moves about the third rotation axis A3. The sliding direction of the second end-of-run pin 68 depends on the rotation direction R5 or R6 of the third motion transmission member 65.
According to other embodiments of the invention (figures 10-11), the first motion transmission member 61 comprises a first end-of-run surface 615 and a second end-of-run surface 616, which are configured for coupling with third end-of-run surfaces 623 of the second motion transmission member 62 and with fourth end-of-run surfaces 653 of the third motion transmission member 65, respectively.
In operation, depending on the rotation direction of the above-mentioned first and second motion transmission members 61 and 62, the first end-of-run surface 615 of the first motion transmission member couples with one corresponding third end-of-run surface 623 of the second motion transmission member 62.
The coupling between the end-of-run surfaces 615 and 623 conveniently occurs when the first motion transmission member 61 decouples from the second motion transmission member 62 after having actuated this latter according to a rotation direction R3 or R4. In this way, further movements of the second motion transmission member 62 along the same rotation direction are conveniently prevented.
In operation, depending on the rotation direction of the above-mentioned first and third motion transmission members 61 and 65, the second end-of-run surface 616 of the first motion transmission member couples with one corresponding fourth end-of-run surface 653 of the second motion transmission member 62.
The coupling between the end-of -run surfaces 616 and 653 conveniently occurs when the first motion transmission member 61 decouples from the third motion transmission member 62 after having actuated this latter according to a rotation direction R5 or R6. In this way, further movements of the third motion transmission member 63 along the same rotation direction are conveniently prevented.
In the embodiments shown in the cited figures, the first motion transmission member 61 comprises shaped disc sectors 615A, 616A protruding from the opposite surfaces 611A, 612A and including the above-mentioned first and second end-of-run surfaces 615, 616.
According to alternative embodiments, the disc sectors 615A, 616A may be separated pieces with respect to the first motion transmission member 61.
In the embodiments shown in the cited figures, the third end-of-run surfaces 623 of the second motion transmission member 62 are formed by a pair of shaped surface portions of the external edge 625, which are symmetrically positioned with respect to the first engaging slot 622. Conveniently, each third end-of-run surface 623 has a complementary shape with respect to the first end-of-run surface 615 of the first motion transmission member 61, in such a way to allow obtaining a shape coupling between these end-of-run surfaces.
In the embodiments shown in the cited figures, the fourth end-of-run surfaces 653 of the third motion transmission member 65 are formed by a pair of shaped surface portions of the external edge 655, which are symmetrically positioned with respect to the second engaging slot 652. Conveniently, each fourth end-of-run surface 653 has a complementary shape with respect to the second end-of-run surface 616 of the first motion transmission member 61.
In principle, however, the first and second end-of-run surfaces 615, 616 of the first motion transmission member 61 and the third and fourth end-of-run surfaces 623, 6653 of the second and third motion transmission members 62, 65 may be realized according to other solutions of known type, which are here not described in details for the sake of brevity.
According to an important aspect of the invention, the motion transmission members 61, 62, 63 are arranged in such a way that the first motion transmission member 61 couples with and actuates the second and third motion transmission members 62, 65 alternately to each other, while moving between opposite end-of-run positions PA, Pc according to the first rotation direction R1 or the second rotation direction R2.
In practice, when it is coupled with and actuates the second motion transmission member 62, the first motion transmission member 61 is decoupled from the third motion transmission member 65.
Similarly, when it is coupled with and actuates the third motion transmission member 65, the first motion transmission member 61 is decoupled from the second motion transmission member 62.
Preferably, the motion transmission members 61, 62, 63 are arranged in such a way that
the first motion transmission member 61 couples with and actuates the second and third motion transmission members 62, 65 sequentially to each other, while moving between opposite end-of-run positions PA, Pc according to the first rotation direction R1 or the second rotation direction R2 (figures 5-7).
In practice, when it moves according to the first rotation direction R1 starting from a suitable end-of-run position PA, the first motion transmission member 61 first couples with and actuates the second motion transmission member 62 while being decoupled from the third motion transmission member 65. Subsequently, by further rotating according to the first rotation direction R1, the first motion transmission member 61 decouples from the second motion transmission member 62 and it couples with the third motion transmission member 63, thereby actuating this latter.
Similarly, when it moves according to the second rotation direction R2 starting from a suitable end-of-run position Pc, the first motion transmission member 61 first couples with and actuates the third motion transmission member 65 while being decoupled from the second motion transmission member 62. Subsequently, by further rotating according to the second rotation direction R2, the first motion transmission member 61 decouples from the third motion transmission member 65 and it couples with the second motion transmission member 62, thereby actuating this latter.
According to the embodiments shown in the cited figures, the above-mentioned convenient features of the motion transmission members 61, 62, 63 are achieved by suitably designing the relative positions of said transmission members and by suitably arranging the engaging pins 611, 612 of the first motion transmission member 61 and the engaging slots 621, 651 of the second and third motion transmission members 62, 65.
A same result can be achieved when the motion transmission members 61, 62, 63 are formed by gear wheels. In this case, the above-mentioned features of the motion transmission members 61, 62, 63 are achieved by suitably designing the relative positions of said transmission members and by suitably arranging the toothed surfaces of said motion transmission members. As mentioned above, the switching apparatus 1 is configured for providing both circuit-breaking and circuit-disconnecting functionalities. The switching apparatus 1 is thus capable of switching in the following three different operating states:

a closed state, in which each electric pole 2 has the first and second pole terminals 11, 12 electrically connected one to another and electrically disconnected from the ground terminal 13. When the switching apparatus is in a closed state, a current can flow along each electric pole 2 between the first and second pole terminals 11, 12; or
an open state, in which each electric pole 2 has the first and second pole terminals 11, 12 and the ground terminal 13 electrically disconnected one from another. When the switching apparatus is in an open state, no currents can flow along the electric poles 2; or
a grounded state, in which each electric pole 2 has the first and second pole terminals 11, 12 electrically disconnected one from another and it has the second pole terminal 12 and the ground terminal 13 electrically connected one to another. When the switching apparatus is in a grounded state, no currents can flow along the electric poles 2. However, the second pole terminal 12 (and therefore the second line conductor connected thereto) is put at a ground voltage.

According to the invention, in operation, the switching apparatus 1 is capable of carrying out different type of manoeuvres, each corresponding to a given transition among the above-mentioned operating states.
In particular, the switching apparatus 1 is capable of carrying out:

an opening manoeuvre, when it switches from a closed state to an open state;
a closing manoeuvre, when it switches from an open state to a closed state;
a disconnecting manoeuvre, when it switches from an open state to a grounded state;
a reconnecting manoeuvre, when it switches from a grounded state to an open state. Obviously, the switching apparatus 1 can switch from a closed state to a grounded state by carrying out an opening manoeuvre and subsequently a disconnecting manoeuvre.

Similarly, the switching apparatus 1 can switch from a grounded state to a closed state by carrying out a reconnecting manoeuvre and subsequently a closing opening manoeuvre.
In order to carry out the above-mentioned manoeuvres of the switching apparatus, the above-mentioned actuation shaft 52 suitably drives the first motion transmission member 61 according to the above-mentioned first rotation direction R1 or second rotation direction R2. In turn, the motion transmission 61 correspondingly drives the second and third motion transmission members 62, 63. In this way, the first and second contact members 6A, 9A of each electric pole are actuated according to the needs.
In general, upon actuation by the actuation shaft 52, the first motion transmission member 61 is reversibly movable between a first end-of-run position PA, which corresponds to a closed state of the switching apparatus, and a second end-of-run position Pc, which corresponds to a grounded state of the switching apparatus.
Conveniently, the first motion transmission member passes through an intermediate position P_B, which corresponds to an open state of the switching apparatus, when it moves between the first and second end-of-run positions PA, Pc (figures 5-7).
The operation of the switching apparatus 1 for each electric pole 2 is now described in more details.

Opening manoeuvre

The switching apparatus 1 carries out an opening manoeuvre, when it switches from a closed state to an open state.
When the switching apparatus is in a closed state, each electric pole 2 has:

the first movable contact 6 coupled to the first fixed contact 5; and
the second movable contact 9 decoupled to the second fixed contact 8.

Therefore, a current can flow between the first and second pole terminals 11, 12 passing through the above-mentioned first contact arrangement.
When the switching apparatus is in a closed state, the first motion transmission member 61 is in the first end-of-run position P_A.
During an opening manoeuvre of the switching apparatus, the actuation shaft 52 actuates the first motion transmission member 61, which moves, according to the first rotation direction R1, from the first end-of-run position P_A to the intermediate position P_B.
When the the first motion transmission member 61 starts moving according to the first rotation direction R1, the first engaging pin 611 of the first motion transmission member 61 engages the first engaging slot 621 of the second motion transmission member 62, thereby coupling the first motion transmission member 61 with the second motion transmission member 62.
The first motion transmission member 61 thus actuates the second motion transmission member 62 and it moves this latter according to the third rotation direction R3 until the first engaging pin 611 of the first motion transmission member 61 disengages from the first engaging slot 621 of the second motion transmission member 62.
As soon as it decouples from the second motion transmission member 62, the first motion transmission member 61 reaches the intermediate position P_B.
Upon actuation by the first motion transmission member 61, the second motion transmission member 62 moves, according to the third rotation direction R3, from a first position P1, at which the first motion transmission member 61 couples with said second motion transmission member, to a second position P2, at which said first motion transmission member decouples from said second motion transmission member.
During its movement between the above-mentioned first and second positions P1, P2 the second motion transmission member 62 actuates the first motion transmission shaft 63, which moves together with the second motion transmission member 62.
In turn, the first motion transmission shaft 63 rotationally actuates each motion transmission mechanism 64, which translationally actuates the corresponding first movable contact member 6A according to the first translation direction D1.
Each first movable contact member 6A therefore moves away from the corresponding first fixed contact member 5A, thereby causing each first movable contact 6 to decouple from the corresponding first fixed contact 5. The current flowing along each electric pole is therefore interrupted.
During an opening manoeuvre of the switching apparatus, the third motion transmission member 63 is not actuated by the first motion transmission member 61. Therefore, the second movable contact member 9A of each electric pole does not move, thereby causing the second movable contact 9 of each electric pole to remain decoupled from the corresponding second fixed contact 8.
At the end of the opening manoeuvre, the switching apparatus 1 switches in an open state, in which each electric pole 2 has:

the first movable contact 6 decoupled to the first fixed contact 5; and
the second movable contact 9 decoupled to the second fixed contact 8.

Therefore, no current can flow between the first and second pole terminals 11, 12 of each electric pole.

Closing manoeuvre

The switching apparatus 1 carries out a closing manoeuvre, when it switches from an open state to a closed state.
When the switching apparatus is in an open state, each electric pole 2 has:

Therefore, a current cannot flow between the first and second pole terminals 11, 12.
When the switching apparatus is in an open state, the first motion transmission member 61 is in the intermediate position P_B.
During a closing manoeuvre of the switching apparatus, the actuation shaft 52 actuates the first motion transmission member 61, which moves, according to the second rotation direction R2, from the intermediate position PB to the first end-of-run position P_A.
When the the first motion transmission member 61 starts moving according to the second rotation direction R3, the first engaging pin 611 of the first motion transmission member 61 engages the first engaging slot 621 of the second motion transmission member 62, thereby coupling the first motion transmission member 61 with the second motion transmission member 62.
The first motion transmission member 61 thus actuates the second motion transmission member 62 and it moves this latter according to the fourth rotation direction R4 until the first engaging pin 611 of the first motion transmission member 61 disengages from the first engaging slot 621 of the second motion transmission member 62.
As soon as it decouples from the second motion transmission member 62, the first motion transmission member 61 reaches the first end-of-run position P_A.
Upon actuation by the first motion transmission member 61, the second motion transmission member 62 thus moves, according to the fourth rotation direction R4, from a second position P2, at which the first motion transmission member 61 couples with said second motion transmission member, to a first position P1, at which said first motion transmission member decouples from said second motion transmission member.
During its movement between the above-mentioned second and first positions P2, P1 the second motion transmission member 62 actuates the first motion transmission shaft 63, which moves together with the second motion transmission member 62.
In turn, the first motion transmission shaft 63 rotationally actuates each motion transmission mechanism 64, which translationally actuates the corresponding first movable contact member 6A according to the second translation direction D2.
Each first movable contact member 6A therefore moves towards the corresponding first fixed contact member 5A, thereby causing each first movable contact 6 to couple with the corresponding first fixed contact 5.
During a closing manoeuvre of the switching apparatus, the third motion transmission member 63 is not actuated by the first motion transmission member 61. Therefore, the second movable contact member 9A of each electric pole does not move, thereby causing the second movable contact 9 of each electric pole to remain decoupled from the corresponding second fixed contact 8.
At the end of the opening manoeuvre, the switching apparatus 1 therefore switches in a closed state. Therefore, a current can flow between the first and second pole terminals 11, 12 of each electric pole.

Disconnecting manoeuvre

The switching apparatus 1 carries out a disconnecting manoeuvre, when it switches from an open state to a grounded state.
Obviously, before carrying out a disconnecting manoeuvre, the switching apparatus has to carry out an opening manoeuvre as described above in order to switch in an open state.
When the switching apparatus is in an open state, each electric pole 2 has:

Therefore, a current cannot flow between the first and second pole terminals 11, 12.
When the switching apparatus is in an open state, the first motion transmission member 61 is in the intermediate position P_B.
During a disconnecting manoeuvre of the switching apparatus, the actuation shaft 52 actuates the first motion transmission member 61, which moves, according to the first rotation direction R1, from the intermediate position P_B to the second end-of-run position P_C.
When the the first motion transmission member 61 starts moving according to the first rotation direction R1, the second engaging pin 612 of the first motion transmission member 61 engages the second engaging slot 651 of the third motion transmission member 65, thereby coupling the first motion transmission member 61 with the third motion transmission member 65.
The first motion transmission member 61 thus actuates the third motion transmission member 65 and it moves this latter according to the fifth rotation direction R5 until the second engaging pin 612 of the first motion transmission member 61 disengages from the second engaging slot 651 of the third motion transmission member 65.
As soon as it decouples from the third motion transmission member 66, the first motion transmission member 61 reaches the second end-of-run position P_C.
Upon actuation by the first motion transmission member 61, the third motion transmission member 65 thus moves, according to the fifth rotation direction R5, from a third position P3, at which the first motion transmission member 61 couples with said third motion transmission member, to a fourth position P4, at which said first motion transmission member decouples from said third motion transmission member.
During its movement between the above-mentioned third and fourth positions P3, P4 the third motion transmission member 65 actuates the second motion transmission shaft 66, which moves together with the third motion transmission member 65.
In turn, the second motion transmission shaft 66 rotationally actuates the second movable contact member 9A of each electric pole according to the fifth rotation direction R5.
Each second movable contact member 9A therefore moves towards the corresponding second fixed contact member 8A, thereby causing each second movable contact 9 to couple with the corresponding second fixed contact 8.
During a disconnecting manoeuvre of the switching apparatus, the second motion transmission member 62 is not actuated by the first motion transmission member 61. Therefore, the first movable contact member 6A of each electric pole does not move, thereby causing the first movable contact 6 of each electric pole to remain decoupled from the corresponding first fixed contact 5.
At the end of the disconnecting manoeuvre, the switching apparatus 1 therefore switches in a disconnected state, in which each electric pole 2 has:

the first movable contact 6 decoupled to the first fixed contact 5; and
the second movable contact 9 coupled to the second fixed contact 8.

Therefore, no current can flow between the first and second pole terminals 11, 12 of each electric pole. The second pole terminal 12 of each electric pole is instead put at a ground voltage.

Reconnecting manoeuvre

The switching apparatus 1 carries out a reconnecting manoeuvre, when it switches from a grounded state to an open state.
When the switching apparatus is in a grounded state, each electric pole 2 has:

the first movable contact 6 decoupled to the first fixed contact 5; and
the second movable contact 9 coupled with the second fixed contact 8.

Therefore, a current cannot flow between the first and second pole terminals 11, 12 and the second pole terminal 12 in instead put at a ground voltage.
When the switching apparatus is in a disconnected state, the first motion transmission member 61 is in the second end-of-run position P_C.
During a reconnecting manoeuvre of the switching apparatus, the actuation shaft 52 actuates the first motion transmission member 61, which moves, according to the second rotation direction R3, from the second end-of-run position P_C to the intermediate position P_B.
When the the first motion transmission member 61 starts moving according to the second rotation direction R1, the second engaging pin 612 of the first motion transmission member 61 engages the second engaging slot 651 of the third motion transmission member 65, thereby coupling the first motion transmission member 61 with the third motion transmission member 65.
The first motion transmission member 61 thus actuates the third motion transmission member 65 and it moves this latter according to the sixth rotation direction R6 until the second engaging pin 612 of the first motion transmission member 61 disengages from the second engaging slot 651 of the third motion transmission member 65.
As soon as it decouples from the third motion transmission member 66, the first motion transmission member 61 reaches the intermediate position P_B.
Upon actuation by the first motion transmission member 61, the third motion transmission member 65 thus moves, according to the sixth rotation direction R6, from a fourth position P4, at which the first motion transmission member 61 couples with said third motion transmission member, to a third position P3, at which said first motion transmission member decouples from said third motion transmission member.
During its movement between the above-mentioned fourth and third positions P4, P3 the third motion transmission member 65 actuates the second motion transmission shaft 66, which moves together with the third motion transmission member 65.
In turn, the second motion transmission shaft 66 rotationally actuates the second movable contact member 9A of each electric pole according to the sixth rotation direction R6.
Each second movable contact member 9A therefore moves away from the corresponding second fixed contact member 8A, thereby causing each second movable contact 9 to decouple from the corresponding second fixed contact 8.
During a reconnecting manoeuvre of the switching apparatus, the second motion transmission member 62 is not actuated by the first motion transmission member 61. Therefore, the first movable contact member 6A of each electric pole does not move, thereby causing the first movable contact 6 of each electric pole to remain decoupled from the corresponding first fixed contact 5.
At the end of the reconnecting manoeuvre, the switching apparatus 1 switches in an open state. The switching apparatus, according to the invention, provides remarkable advantages with respect to the known apparatuses of the state of the art.
The switching apparatus of the invention includes an improved motion transmission assembly, which allows actuating the movable contact members 6A, 9A of each electric pole independently one from another.
The switching apparatus of the invention can thus provide the requested current-breaking functionalities and circuit-disconnecting functionalities even if it includes a single actuator and a single actuation shaft to operate (differently from the switching apparatuses of the state of the art).
The switching apparatus of the invention therefore has a very compact, simple and robust structure with relevant benefits in terms of size optimization and flexibility of use. Additionally, it provides high levels of reliability for the intended applications.
The switching apparatus of the invention includes a motion transmission assembly, which allows translationally actuating the first movable contact members 6A of each electric pole.
This circumstance allows designing the contact arrangement 5, 5A, 6, 6A, 7 intended to provide current-breaking functionalities according to an arc-quenching puffer configuration, which allows obtaining high level performances in terms of arc suppression, even not using SF6 as insulating gas.
The switching apparatus of the invention can thus exploit air or another environmental-friendly gas as insulating gas and it therefore has a low environmental impact in comparison to currently available solutions of the state of the art.
The switching apparatus, according to the invention, is of relatively easy and cheap industrial production and installation on the field.

Claims

A switching apparatus (1) for medium voltage electric systems, said switching apparatus comprising one or more electric poles (2),
wherein, for each electric pole, said switching apparatus comprises:
- a first pole terminal (11), a second pole terminal (12) and a ground terminal (13), said first pole terminal being electrically couplable with a first conductor of an electric line, said second pole terminal being electrically couplable to a second conductor of said electric line and said ground terminal being electrically couplable to a grounding conductor;

- a first contact arrangement including a first fixed contact member (5A) and a first movable contact member (6A), said first fixed contact member being electrically connected to said first pole terminal (11) and including a first fixed contact (5), said first movable contact member being electrically connected to said second pole terminal (12) and including a first movable contact (6), said first movable contact member being reversibly movable along a corresponding translation axis (A), so that said first movable contact can be coupled with or decoupled from said first fixed contact;

- a second contact arrangement including a second fixed contact member (8A) and a second movable contact member (9A), said second fixed contact member being electrically connected to said ground terminal (13) and including a second fixed contact (8), said second movable contact member being electrically connected to said second pole terminal (12) and including a second movable contact (9), said second movable contact member being reversibly movable about a corresponding rotation axis (A3), so that said second movable contact can be coupled to or decoupled from said second fixed contact;
wherein said switching apparatus further comprises:
- an actuation assembly for actuating the first and second movable contact members (6A, 9A) of each electric pole during a switching manoeuvre of said switching apparatus, said actuation assembly including an actuation shaft (52) reversibly movable about a corresponding rotation axis (A1);

- a motion transmission assembly for transmitting mechanical forces provided by said actuation shaft (52) to the first and second movable contact members (6A, 9A) of each electric pole;
characterised in that said motion transmission assembly comprises:
- a first motion transmission member (61) coupled to said actuation shaft (52) to be actuated by rotational mechanical forces provided by said actuation shaft, said first motion transmission member being reversibly movable about a first rotation axis (A1) according to a first rotation direction (R1) or according to a second rotation direction (R2), opposite to said first rotation direction, upon actuation by said actuation shaft (52);

- a second motion transmission member (62) couplable with said first motion transmission member (61) to be actuated by rotational mechanical forces provided by said first motion transmission member, said second motion transmission member being reversibly movable about a second rotation axis (A2) upon actuation by said first motion transmission member;

- a first motion transmission shaft (63) coupled with said second motion transmission member to be actuated by rotational mechanical forces provided by said second motion transmission member;

- for each electric pole, a motion transmission mechanism (64) coupled to said first motion transmission shaft (63) and to the first movable contact member (6A) of each electric pole, said motion transmission mechanism being actuated by rotational mechanical forces provided by said first motion transmission shaft and transmitting translational mechanical forces to each first movable contact member to actuate said first movable contact member;

- a third motion transmission member (65) couplable with said first motion transmission member (61) to be actuated by rotational mechanical forces provided by said first motion transmission member, said third motion transmission member being reversibly movable about a third rotation axis (A3) upon actuation by said first motion transmission member;

- a second motion transmission shaft (66) coupled with said third motion transmission member (65) to be actuated by rotational mechanical forces provided by said third motion transmission member, said second motion transmission member being coupled with the second movable contact member (9A) of each electric pole, said second motion transmission shaft transmitting rotational mechanical forces provided by said motion transmission shaft (65) to each second movable contact member to actuate said second movable contact member.
Switching apparatus, according to claim 1, characterised in that said first motion transmission member (61) couples with and actuates said second and third motion transmission members (62, 65) alternately to each other, while said first motion transmission member moves between opposite end-of-run positions (P_A, P_C) according to said first rotation direction (R1) or said second rotation direction (R2).
Switching apparatus, according to claim 2, characterised in that said first motion transmission member (61) couples with and actuates said second and third motion transmission members (62, 65) sequentially to each other, while said first motion transmission member moves between opposite end-of-run positions (P_A, P_C) according to said first rotation direction (R1) or said second rotation direction (R2).
Switching apparatus, according to one or more of the previous claims, characterised in that said first motion transmission member (61) is reversibly movable between a first end-of-run position (P_A), which corresponds to a closed state of said switching apparatus, and a second end-of-run position (P_C), which corresponds to a grounded state of said switching apparatus, said first motion transmission member passing through an intermediate position (P_B), which corresponds to an open state of said switching apparatus, when moving between said first and second end-of-run positions (P_A, P_B).
Switching apparatus, according to claim 4, characterised in that, during an opening manoeuvre of said switching apparatus:
- said first motion transmission member (61) moves, according to said first rotation direction (R1), from said first end-of-run position (P_A) to said intermediate position (P_B);

- said second motion transmission member (62) moves from a first position (P1), at which said first motion transmission member (61) couples with said second motion transmission member, to a second position (P2), at which said first motion transmission member decouples from said second motion transmission member;

- the first movable contact member (6A) of each electric pole moves away from the corresponding first fixed contact member (5A), thereby causing the first movable contact (6) of each electric pole to decouple from the corresponding first fixed contact (5);

- said third motion transmission member (63) is not actuated by the said first motion transmission member (61);

- the second movable contact member (9A) of each electric pole does not move, thereby causing the second movable contact (9) to remain decoupled from the corresponding second fixed contact (8).
Switching apparatus, according to one of the claims from 4 to 5, characterised in that, during a disconnecting manoeuvre of said switching apparatus:
- said first motion transmission member (61) moves, according to said first rotation direction (R1), from said intermediate position (P_B) to said second end-of-run position (P_C);

- said third motion transmission member (65) moves from a third position (P3), at which said first motion transmission member (61) couples with said third motion transmission member, to a fourth position (P4), at which said first motion transmission member decouples from said third motion transmission member;

- the second movable contact member (9A) of each electric pole moves towards the corresponding second fixed contact member (8A), thereby causing the second movable contact (9) of each electric pole to couple with the corresponding second fixed contact (8);

- said second motion transmission member (62) is not actuated by the said first motion transmission member (61);

- the first movable contact member (6A) of each electric pole does not move, thereby causing the first movable contact (6) of each electric pole to remain in a decoupled position from the corresponding first fixed contact (5).
Switching apparatus, according to one of the claims from 4 to 6, characterised in that, during a reconnecting manoeuvre of said switching apparatus:
- said first motion transmission member (61) moves, according to said second rotation direction (R2) from said second end-of-run position (P_C) to said intermediate position (P_B);

- said third motion transmission member (65) moves from a fourth position (P4), at which said first motion transmission member (61) couples with said third motion transmission member to a third position (P3), at which said first motion transmission member decouples from said third motion transmission member;

- the second movable contact member (9A) of each electric pole moves away from the corresponding second fixed contact member (8A), thereby causing the second movable contact (9) of each electric pole to decouple from the corresponding second fixed contact (8);

- said second motion transmission member (62) is not actuated by the said first motion transmission member (61);

- the first movable contact member (6A) of each electric pole does not move, thereby causing the first movable contact (6) of each electric pole to remain in a decoupled position from the corresponding first fixed contact (5).
Switching apparatus, according to one of the claims from 4 to 7, characterised in that, during a closing manoeuvre of said switching apparatus:
- said first motion transmission member (61) moves, according to said second rotation direction (R1), from said intermediate position (P_B) to said first end-of-run position (P_A);

- said second motion transmission member (62) moves from a second position (P2), at which said first motion transmission member (61) couples with said second motion transmission member, to a first position (P1), at which said first motion transmission member decouples from said second motion transmission member;

- the first movable contact member (6A) of said electric pole moves towards the corresponding first fixed contact member (5A), thereby causing the first movable contact (6) of said electric pole to couple with the corresponding first fixed contact (5);

- said third motion transmission member (63) is not actuated by the said first motion transmission member (61);

- the second movable contact member (9A) of each electric pole does not move, thereby causing the second movable contact (9) to remain decoupled from the corresponding second fixed contact (8).
Switching apparatus, according to one or more of the previous claims, characterised in that said first motion transmission member (61) comprises a first engaging pin (611) and a second engaging pin (612) protruding from at least a surface (611A, 612A) of said first motion transmission member (61), said first and second engaging pins being angularly spaced one from another with respect to the first axis of rotation (A1) of said first motion transmission member.
Switching apparatus, according to claim 9, characterised in that said first and second engaging pins (611, 612) protrude from opposite surfaces (611A, 612A) of said first motion transmission member (61).
Switching apparatus, according to one of the claims from 9 to 10, characterised in that said second motion transmission member (62) comprises a first engaging slot (621) extending radially with respect to the second axis of rotation (A2) of said second motion transmission member (62), said first engaging pin (611) being engageable with said first engaging slot.
Switching apparatus, according to one of the claims from 9 to 11, characterised in that said third motion transmission member (65) comprises a second engaging slot (651) extending radially with respect to the third axis of rotation (A3) of said third motion transmission member (65), said second engaging pin (612) being engageable with said second engaging slot.
Switching apparatus, according to one of the previous claims, characterised in that said motion transmission assembly (60) comprises a first end-of-run pin (67) and a second end-of-run pin (68) fixed to a support member (4) of said switching apparatus, said first end-of-run pin (67) being coupled with a first end-of-run slot (622) of said second motion transmission member (62), said second end-of-run pin (68) being coupled with a second end-of-run slot (652) of said third motion transmission member (65).
Switching apparatus, according to one of the claims from 1 to 12, characterised in that said first motion transmission member (61) comprises a first end-of-run surface (615) and a second end-of-run surface (616), said first end-of-run surface (615) being couplable with corresponding third end-of-run surfaces (623) of said second motion transmission member (62), said second end-of-run surface (616) being couplable with corresponding fourth end-of-run surfaces (653) of said third motion transmission member (65).
Switching apparatus, according to one of the previous claims, characterised in that the first contact arrangement (5, 5A, 6, 6A) of each electric pole (2) has an arc-quenching puffer configuration.
Switching apparatus, according to one of the previous claims, characterised in that it is a load-break switch for medium voltage electric systems.